The invention provides a sewing cuff assembly for mounting to the body of a heart valve prosthesis. The sewing cuff assembly comprises a resiliently deformed spring for exerting a force directed toward the orifice structure. When a torque is applied to the valve, the force results in a rotation-resisting torque sufficient to resist rotation during normal operation of the valve after implantation but low enough to permit assisted rotation, as during surgery.

Artificial heart valves, which may be implanted in the human heart to replace natural valves, are essentially check valves which permit the flow of blood through the valves in a downstream direction, but block regurgitation of blood in a reverse or upstream direction. Heart valve prostheses typically fall into one of two categories--mechanical valves and tissue valves. The present invention finds its principal application in the field of mechanical valves, although it is not limited to this application as it may be used, for example, for tissue valves. Such mechanical valves generally include an annular valve housing or body having a central orifice which provides a passageway for blood. A valving mechanism, typically including occluders, is mounted in the orifice and opens and closes to regulate the passage of blood. One such valve which has enjoyed considerable success is disclosed in commonly assigned U.S. Pat. No. 4,276,658.
The outer circumferential surface of the valve body disclosed in the '658 patent includes a groove, which has facilitated the coupling of a suturing ring or sewing cuff to the valve body. The sewing cuffs for heart valve prostheses are generally a soft, flexible torus-like element through which sutures may pass to secure the sewing cuff, and consequently the heart valve, to the heart tissue.
Another method of coupling the sewing cuff to the valve body is shown in U.S. Pat. No. 5,071,431 to Sauter et al. Sauter et al. discloses a heart valve where a sewing cuff which is attached to a stiffening ring, with the stiffening ring being coupled to the valve body by a locking ring which rides in grooves in the outer periphery of the valve body and the inner periphery of the stiffening ring.
After a damaged or diseased natural valve structure is removed from the patient, the prosthesis is typically seated in the proper orientation and the sewing cuff is sewn to the peripheral heart tissue. Depending on the particular valve structure, care must be taken to ultimately orient the valve occluders to ensure that the valving mechanism is in the most favorable anatomical position to provide proper blood flow and to ensure that the valve operates without interference from surrounding heart tissue. This must either be done as the sewing cuff of the valve is sutured into place, or if the sewing cuff is rotatable relative to the valve, this can be done after the sewing cuff is secured to the heart tissue. While this latter arrangement is convenient and can obviate the need to remove and resuture a valve to effect a rotation, a rotatable valve must meet several criteria.
For example, the torsional force required to rotate the valve must be low enough so that the surgeon is able to rotationally position the valve with ease and without damage to the surrounding tissue. Once implanted, however, the valve body must maintain the desired position during the remainder of the surgery, and thereafter. Consequently, the torque required to initiate rotation must be great enough to prevent spontaneous in vivo rotation. Thus, the torsional force required to rotate the valve body within the sewing cuff should be predictable and fall within a narrow predetermined range such that it may be easily adjusted by the surgeon, yet be resistant to undesirable in vivo rotation once implanted. Moreover, the desired torque characteristics should be repeatable from valve to valve without significant variation.
The torsional force required to rotate the valve body relative to the sewing cuff will be determined by the manner in which the sewing cuff is retained on the valve body. Various methods have been proposed to rotatably secure the sewing cuffs of heart valve prostheses to the valve bodies. For example, U.S. Pat. No. 4,197,593 to Kaster et al. discloses a heart valve where a sewing cuff is sutured to a polymeric slip ring that slides along the surface of the valve body. U.S. Pat. No. 4,535,483 to Klawitter et al. discloses a heart valve where the sewing cuff is carried by deformable metal retainer rings which engage a stiffening ring disposed in and secured to a peripheral groove in the valve body. U.S. Pat. No. 5,104,406 to Curicio et al. discloses a heart valve where the fabric of the sewing cuff is stitched to a core, which directly abuts and rides the groove in the valve body; the core and the valve additionally sandwich the fabric along the annular space where the fabric is stitched to the core. U.S. Pat. No. 5,178,633 to Peters discloses a heart valve where the sewing cuff is coupled to the valve body by continuous fastener bands. The frictional engagement between the fabric tube and the valve body or "orifice ring" is controlled by the internal diameter of the fastener bands, which may be manufactured with precision. A need exists for an improved rotatable heart valve prosthesis.

Rotatable cuff assembly for a heart valve prosthesis


A porous carrier containing an immobilized biologically active material is prepared in which a relatively large amount of an enzyme or an antibody has been immobilized in a manner that produces a low diffusion resistance toward reagents and products. The porous carrier is produced by fixing enzymes or antibodies within internal micropores of the carrier and mechanically compressing the carrier to a final thickness which is in the range of about 0.20 to 0.80 times the uncompressed carrier thickness. The compressed carrier may have a density about 1.25 to about 5.0 times the density of the carrier before compressing. Surprisingly, the compressed carrier exhibits less diffusion resistance to specific reagents and products than would an uncompressed carrier. A preferred porous carrier is a semi-permeable membrane made from synthetic polymers, such as polyvinylidine difluoride.

Biologically active materials, such as proteins, are important catalysts for industrial and analytical chemistry because they are highly specific to particular reagents and because they exhibit high catalytic activity and speed of reaction. Enzymes, antibodies, and enzyme-antibody conjugates are sub-classes of proteins. However, biologically active proteins are often difficult to isolate and expensive to make and use. It is usually desirable to utilize proteins in an immobilized form in which biologically active proteins are attached to a solid carrier which confines the active proteins and permits their reuse. Several means of immobilizing biologically active proteins on solid carriers are known, such as adsorption, ionic bonding, entrapment, and covalent bonding.
Proteins, of which enzymes and antibodies are sub-classes, are relatively large molecules that contain positively charged, negatively charged, and uncharged non-ionic portions. Ionicly bound proteins are produced when a charged portion of the protein comes in close contact to an oppositely charged portion of a solid carrier surface. Under many conditions this attachment is irreversible. Adsorptively bound proteins are produced when the uncharged portion of the protein comes in close contact to an uncharged, non-ionic portion of a solid carrier surface. Several ionic and adsorptive attachments may be necessary to irreversibly bind a single protein.
Covalent bonds that immobilize proteins are formed by linking amino or carboxyl groups, which are present in every enzyme, with polar functional groups attached to the carrier. The functional groups can be derived from components normally present in the material that forms a carrier substrate or the functional groups can be added to the carrier. Suitable functional groups include carboxyl groups, amino groups, sulphonic acid groups, imino groups, thio groups, hydroxyl groups, azo groups, epoxy groups, aldehyde groups, acid chloride groups, activated carbonyl groups, pyridyl groups, and phosphoryl groups. The functional groups may be further activated by chemical treatment to enhance their ability to join with the amino or carboxyl groups present in the protein molecules.
Known techniques for covalently immobilizing proteins on porous carriers have significant limitations. For example, large amounts of biologically active material can be immobilized inside a bulk carrier, such as a block of porous material or thick porous membrane, but the depth and physical properties of the protein layers so immobilized are difficult to control. Also, diffusion into and out of blocks and relatively thick membranes is slow.
By another technique, biologically active material, such as enzymes, antibodies, or enzyme-antibody conjugates can be immobilized in small amounts as a thin layer inside thin membranes or as a thin layer on the surface carrier membranes, but the limited amount of biologically active material which can be deposited into the thin layers is often insufficient to carry out a desired chemical reaction. Further, biological materials tend to deactivate over time and a carrier with only a small amount of active material may not function over a period of time long enough to be practical.

Preparation of a compressed membrane containing immobilized biologically acting material


A control apparatus of a transmission includes a hydraulic pressure circuit, an abnormality detector, and a controller. The transmission performs shifting operation of the transmission. The controller controls the shifting operation by controlling, as a first control operation, a control pressure adjusting value to allow a line pressure and a control pressure to have a correlation with each other and by using, as a value of the line pressure, a value calculated on a basis of a detected value of the control pressure. The controller controls the shifting operation by controlling, as a second control operation, the control pressure adjusting valve to allow the line pressure and the control pressure to have a correlation with each other and by using, as a value of the control pressure, a value calculated on a basis of a detected value of the line pressure.

The technology relates to a transmission to be mounted in a power feeding system of a structure such as a vehicle, a control apparatus of the transmission, and a method of controlling the transmission.
In a transmission to be mounted in a structure such as a vehicle, a control unit of the vehicle calculates a target shifting ratio on the basis of factors including a throttle position and a vehicle traveling speed. In the transmission, shifting operation of the vehicle is so performed by means of, for example, a hydraulic pressure as to cause a shifting ratio of the vehicle to come close to the target shifting ratio. For example, reference is made to Japanese Unexamined Patent Application Publication No. 2007-71272.

Transmission, control apparatus of transmission, and method of controlling transmission


Techniques for performing a “null-aware” anti-join operation are described. Unnesting using anti-join of NOT IN/ALL subquery uses null-aware anti-join operation, resulting in a rewritten query that, when computed, produces results consistent with the NULL semantics of NOT IN/ALL subquery. The semantics of the “null-aware” anti-join operation allow the query having the NOT IN/ALL subquery to be rewritten even though a no-NULL restriction requirement, for the operands of the anti-join condition in the query, may not be met.

Relational and object-relational database management systems store information in tables of rows in a database. To retrieve data, queries that request data are submitted to a database server, which computes the queries and returns the data requested.
Queries submitted to the database server must conform to the syntactical rules of a particular query language. One popular query language, known as the Structured Query Language (SQL), provides users a variety of ways to specify information to be retrieved.
A query submitted to a database server is evaluated by a query optimizer. Based on the evaluation, the query optimizer generates an execution plan that defines operations for executing the query. Typically, the query optimizer generates an execution plan optimized for efficient execution. The optimized execution plan may be based on a rewrite of the query.
A common type of query that is optimized is a query that contains a subquery whose join condition involves the NOT IN/ALL operator (NOT IN is equivalent to !=ALL). In data-warehouses with reporting applications, such queries and subqueries are usually evaluated on very large sets of data. Thus, it is critical to make such queries scale in any SQL execution engine. When such queries are not optimized using anti-join, the subquery is executing an operation that is effectively a Cartesian product, which is quite inefficient.
One common technique for optimizing these kinds of queries is anti-join unnesting. In anti-join unnesting, a subquery operand of an NOT IN/ALL operator is either merged with the containing "outer query" or an inline view is created for the subquery and the columns in the join condition of the NOT IN/ALL operator are used to form a join condition of an anti-join. To illustrate anti-join unnesting, the following query Q1 is transformed into Q2. Note that in this example both the columns T1.x and T2.y contain only non-null values.
Q1:SELECT T1.cFROM T1WHERE T1.x NOT IN (SELECT T2.y        FROM T2        WHERE T2.z > 10);Q2:SELECT T1.cFROM T1, T2WHERE T1.x A= T2.y and T2.z > 10;
Query Q1 is rewritten by merging the subquery operand of the NOT IN operator of Q1 into Q1's outer query to produce query Q2. Query Q2 contains the anti-join operator T1.x A=T2.y, which is based on the join columns (i.e. T1.x, T2.y) of the NOT IN operator in query Q1. The anti-join operator specifies the join condition T1.x A=T2.y. A condition that compares columns between tables, is hereafter referred to as a join condition. A joining column is a column being compared, by an operator in a join condition, to a column of another table. Query Q2 may be executed far more efficiently than query Q1. Note that the anti-join operator A= is non-standard SQL and is used here for the purpose of illustration only.
The anti-join is an asymmetric join, where a row of the "left table" is returned only if it does not match (i.e. does not satisfy the connecting condition) with any row in the "right table". The term "left" is used to designate the table whose rows are returned by an anti-join operation, and not to designate the table's position within an expression. Similarly, the term "right" is used to designate the table whose rows are to be matched (or not) to a left table by an anti-join operation, and not to designate the table's position within an expression. Nevertheless, the notation T1.x A=T2.y is used to represent an anti-join, where T1 is the table on the left of the anti-join and T2 is the table on the right of the anti-join.
The term table refers generally to any set of rows or tuples stored in a database table or computed for an expression, such as a query or subquery. For example, the rows returned by the NOT IN/ALL subquery of Q1 can be referred to as a table.
In Q2, under the semantics of an anti-join, for each row of T1, the join condition T1.x=T2.y is evaluated, and if no match is found with any row of T2, then that row of T1 is returned. The semantics of evaluating the NOT IN/ALL subquery in Q1 is identical to the semantics of the anti-join summarized below.                1. If T2 contains no rows after the application of the filter predicate, then return all the rows of T1 and terminate.        2. For each row of T1, return the row, if T1.x has no match with any row of T2.
The anti-join unnesting transformation of Q1 to Q2 is an example of one form anti-join unnesting in which a subquery is merged into the outer query. In another form, a subquery is converted into an inline view of the outer query. The transformation of Q3 to Q4 illustrates this latter form. Again in this example, both the columns T1.x and T2.y contain only non-null values.
Q3:SELECT T1.cFROM T1WHERE T1.x NOT IN (SELECT T2.y        FROM T2, T3        WHERE T2.z = T3.w          and T2.k > 10);Q4:SELECT T1.cFROM T1,  (SELECT T2.y AS Y   FROM T2, T3   WHERE T2.z = T3.w    and T2.k > 10) VWHERE T1.x A= V.y;
Query Q4 is rewritten by converting the subquery operand of the NOT IN operator of Q3 into inline view V of Q4. Query Q4 contains the anti-join operator T1.x A=T2.y, which is based on the join columns (i.e. T1.x, T2.y) of the NOT IN operator in query Q3. The anti-join operator specifies the join condition T1.x A=T2.y.
Unfortunately, anti-join unnesting for NOT IN/ALL subqueries may only be performed when a certain restriction, referred to herein as the no-NULL restriction, is met. The no-NULL restriction requires that both operands of the anti-join condition are free of NULL values for every row in the left and right tables. For example, query Q1 satisfies the no-NULL restriction only when column T1.x does not contain any NULL values, and no row in T2 that satisfies the predicate filter condition T2.z contains a NULL value in column T2.y.
The no-NULL restriction bars anti-join unnesting for a large proportion of NOT IN/ALL subqueries; therefore the optimizer is forced to choose a sub-optimal plan. Clearly, there is a need for techniques and mechanisms for performing anti-join unnesting when the no-NULL restriction is not satisfied.
The approaches described in this section are approaches that could be pursued, but not necessarily approaches that have been previously conceived or pursued. Therefore, unless otherwise indicated, it should not be assumed that any of the approaches described in this section qualify as prior art merely by virtue of their inclusion in this section.


The present invention includes an approach to index tree structure changes which provides high concurrency while being usable with many recovery schemes and with many varieties of index trees. The present invention permits multiple concurrent structure changes. In addition, all update activity and structure change activity above the data level executes in short independent atomic actions which do not impede normal database activity. Only data node splitting executes in the context of a database transaction. This feature makes the approach usable with diverse recovery mechanisms, while only impacting concurrency in a modest way. Even this impact can be avoided by re-packaging the atomic actions, at the cost of requiring more from the recovery system.

The higher a node is in an index tree, the more likely it is to be accessed. This is because data associated with lower nodes are typically accessed through at least one upper node. Thus, the manner in which the nodes, and their associated data, are linked and arranged is critical with respect to the speed and accuracy of the data access.
As illustrated in FIG. 1, a common type of indexing arrangement permits multiple (virtual) processors 10 concurrent access to an index tree in memory 20. The subject of concurrency in indexing arrangements has a long history, with many aspects of indexing discussed at length. For example, concurrency in B.sup.+ -trees has been addressed in Bayer, R., Schkolnick, M., Concurrency of operations on B-trees, Acta Informatica Vol. 9 (1977) pp 1-21; Lehman, P., Yao, S. B., Efficient Locking For Concurrent Operations On B-Trees, ACM Trans on Database Systems, Vol. 6, No. 4 (December 1981) pp. 650-670; Sagiv, Y., Concurrent Operations On B* Trees With Overtaking, Journal of Computer and System Sciences, Vol. 33, No. 2, (1986) pp. 275-296; Salzberg., B., Restructuring The Lehman-Yao Tree, Northeastern University Technical Report TR BS-85-21 (1985), Boston, Mass.; Shasha, D., Goodman, N., Concurrent Search Structure Algorithms ACM Trans. on Database Systems, Vol. 13, No. 1 (March 1988) pp. 53-90. Unfortunately, except for the last listed paper, none of these papers addresses the problem of system crashes during structure changes.
The occurrence of a system crash during a structure change can severely impede the normal use of the system. In a multiple access system, a structure change to a set of nodes in an index tree typically requires an access lock on the data associated with those nodes. This permits the system to rearrange the data and the associated linking information without losing the identity of the data, its node and/or its relation to other nodes in the index. In structures such as the B.sup.+ -tree, where all data is stored in the leaves, upper level index nodes are only written when the shape of the tree changes. It is important then that these structure changes hold only short-term locks on index nodes, i.e., prohibit reads on data for the associated node(s), to facilitate concurrent access to the leaves via the index.
If a system crash occurs while the tree is being restructured, access to the leaves that are linked to, and/or emanate from, the index nodes may be blocked. While the likelihood of this blockage problem is dependent on the point at which the crash occurred during the restructuring process, because the inaccessibility of the blocked data may be permanent, any possibility of such an occurrence is an unacceptable possibility.
In Mohan, C. and Levine, F., ARIES/IM, An Efficient And High Concurrency Index Management Method Using Write-Ahead Logging, IBM Research Report RJ 6846, (August 1989) IBM Almaden Research Center, San Jose, Calif., a solution to this crash problem is suggested. The solution employs a nodal linking technique that anticipates a system crash by logging the next steps that must be executed in the event that a system crash occurs. In this manner, the system has a record of what it is about to do next (after a crash occurs).
This technique, unfortunately, is burdensome in terms of its applicability and flexibility for various types of index trees and recovery methods.
Accordingly, there is a need for method of concurrency in an indexing arrangement that is capable of managing concurrency and recovery for a wide class of index tree structures.

Concurrency and recovery for index trees with nodal updates using multiple atomic actions by which the trees integrity is preserved during undesired system interruptions


A metallic storage holster and cable for locking a handgun in place and preventing access to the handgun by unauthorized persons. The cable is welded onto a one side of the storage holster. The non-welded cable end is formed into a loop. The loop is then secured over a "U" latch welded onto the other side of the storage holster. The latch is large enough to allow a lock to be inserted through the eye of the latch once the looped cable end has been fitted. Once the lock is in place, access to the handgun is restricted to the individual able to open the lock. A metallic plate is welded onto one side of the storage holster and holes are cut through both sides of the storage holster to allow lag bolts to be inserted and countersunk though the side with the plate attached thereto. The lag bolts, once in place, are used to mount the storage holster. Once a handgun is locked in place access to the lag bolts from the other side of the storage holster is blocked.

This invention relates to storage means for handguns, and in particular to a holster for the storage of a handgun and for the prevention of the handgun being removed by an unauthorized person.
The present invention discloses a means for the easy and economical storage of personal handguns and the like. In addition, the invention is used for the prevention of the armament from being used by unauthorized persons such as children and burglars.
With the increase in burglaries and other crimes effecting the home, many home owners have chosen to arm themselves. In order to be effective a firearm must be readily available. However, given the dangerous nature of having a loaded firearm about for use by unauthorized persons, additional safety measures need to be taken with the firearm's storage.
The prior art discloses complicated apparatuses for use in securing and controlling access to firearms. U.S. Pat. No. 5,108,019, issued to Woodward et al., discloses a holster including a flexible strap fitting behind the trigger of a handgun to secure the handgun in a holster. The Woodward et al. apparatus also includes an alarm system that is activated when said strap is unfastened. This apparatus is fundamentally distinguished from the present invention in that the primary function of the Woodward et al. apparatus is to warn the household of the handguns removal and potentially scare children or other unauthorized users away from tampering with the handgun. The instant apparatus is designed to prevent a firearms removal rather than warn of its removal.
U.S. Pat. No. 4,858,799, issued to Young, discloses a holster with a locking mechanism specially designed to fit snugly about a specific part of a handgun. The apparatus includes a radially moveable arm that is locked into place by means of a locking screw. Once in place the arm blocks the removal of the handgun. This apparatus is distinguished from the instant invention in several respects. The Young apparatus is shown as being warn on a belt about the waste. The instant apparatus is made of steel and is intended to be mounted on a wall. The Young invention requires the arm to fit about a specific part of the handgun thus making the apparatus handgun specific. The instant invention may be used with any firearm that can be made to securely fit within the instant holster. The Young invention's locking means includes a locking screw that can be easily accessed and undone by anyone. The instant invention specifically calls for a locking means that is not accessible nor undone by anyone except the intended owner of the firearm. The last of these distinctions is a fundamental difference between the Young and instant apparatus.
Although other known prior art teaches of storing a firearm in a mounted lock box, none disclose use of a holster. A holster, used as in the instant invention, allows for the storage of a variety of firearms, as oppose to being firearm specific like the prior art. The present invention also permits a gun collector or a gun store to display a firearm, especially a handgun, in a safe and secure environment.


A combination turbojet-ramjet engine for powering a hypersonic aircraft is disclosed wherein the intake duct for the ramjet portion of the engine is centrally located within the turbojet portion of the engine in order to improve the access from outside the engine to the turbojet engine portion, as well as to maximize the use of common components and to simplify the control systems for changing from turbojet operation to ramjet operation and vice versa. The ramjet intake duct extends generally parallel to the longitudinal axis of the hypersonic aircraft engine and is located radially inwardly of the compressor, the combustion chamber and the turbine wheel of the turbojet engine portion. Flow control devices are located on the turbojet engine air intake, as well as the ramjet intake duct to control the supply of air to the respective engine portions.

The present invention relates to a hypersonic aircraft engine, more particularly such an engine capable of being operated in either a turbojet or a ramjet mode.
It is known in the art to use air-breathing turbojet engines to power aircraft to speeds approaching Mach 4 and to use ramjets to power the aircraft up to speed of Mach 7 or 8. It is also generally known to combine these engines into a single power plant to power hypersonic aircraft.
Such combined power plants have typically utilized a central air inlet duct to supply air to the turbojet engine and have utilized an annular duct enclosing the turbojet engine and/or the turbojet engine inlet duct in order to supply air to the ramjet portion of the power plant. Such designs are disclosed in U.S. Pat. Nos. 3,540,221 and 4,909,031, and have been discussed in Publication No. IAF-90-256 of the 41st Congress of the International Astronautical Federation in Dresden, Germany on Oct. 6-12, 1990.
While such power plants have proven theoretically feasible, they have suffered practical drawbacks due to their inherent complexity and the difficulties in accessing the turbojet engine for repair and/or maintenance.

Turbojet-ramjet hypersonic aircraft engine

Societe Nationale d'Etude et de Construction de Moteurs d'Aviation ("S.N.E.C.M.A.")


A circuit to mitigate arc failures in an electrical power distribution system can include a solid state distribution system connected to a source of power and to a load, a solid state power controller (SSPC) having a set of field effect transistors (FETs) responsive to command signals from the SSPC wherein an arc in a wire bond of a failed FET can trigger a predetermined sequence to quench the arc and isolate remaining wire bond material in the failed FET from contaminating a creepage path.

Commercial aircraft typically include an electrical power distribution system which can distribute electricity to loads on the aircraft and protect wires and loads from hazards. Solid state distribution units within the electrical power distribution system contain many semiconductors to efficiently distribute high voltage direct current and/or alternating current. An arc failure of a single semiconductor at high voltages needs to be managed.

Arc mitigation in electrical power distribution system


An angled wireless charging pocket of a luggage article may include a first cradle arranged to receive and secure at least portions of a power supply, and a second cradle arranged to receive and secure at least portions of a mobile device, the first and second cradles of the pocket aligned at a lower corner and arranged such that the power supply and the mobile device are held and engaged in overlying alignment at the lower corner.

Many mobile devices (e.g., smartphones, tablets, etc.) now have the function of charging wirelessly through various charging docks, pads, and battery packs. Wireless charging functionality has made its way into use in consumer products, such as luggage articles. In the case of luggage articles, many solutions are costly and require in-depth engineering to create a system that can charge many types of mobile devices. Some solutions cannot adapt to various sizes of mobile devices and wireless power supplies. In addition, some solutions do not hold mobile devices and wireless power supplies in a way that engages the mobile device with the wireless power supply while being carried. For example, some solutions allow frequent disengagement of the mobile device from the wireless power supply, reducing the effectiveness of charging a mobile device while being carried.
It is therefore desirable to provide an improved luggage case, and more specifically an improved pocket that addresses one or all of the above-described problems and/or which more generally offers improvements or an alternative to existing arrangements.
Documents that may be related to the present disclosure include U.S. Pat. No. 9,362,777B2, U.S. Pat. No. 9,461,499B2, U.S. Pat. No. 9,729,003B1, U.S. Ser. No. 10/063,086B2, US20150326044A1, US20160190817A1, US20160322851A1, US20170117742A1, and US20170302099A1.


A technique is provided for utilizing an optical fiber in a variety of sensing applications and environments by beneficially routing the optical fiber. A continuous optical fiber is created to provide optical continuity between two ends of the optical fiber. The optical continuity is created with the assistance of an optical turnaround constructed in a simple, dependable form able to control the bend of the optical fiber as it extends through the optical turnaround.

Optical fibers are used in a variety of sensing and other applications. For example, optical fiber has been used as a distributed temperature sensor in oilfield applications where the temperature profile can be applied in, for example, detection of water breakthrough, detection of leaks, and gas lift monitoring and optimization. The optical fiber is utilized by injecting light into the fiber, measuring the backscattered light, and then processing the results to determine temperature along the length of the fiber.
Research has shown that distributed temperature sensor measurements are more accurate when performed in a double-ended configuration such that optical continuity exists between two optical fiber ends connected to a distributed temperature sensor control system. By preparing this double-ended configuration, light can be sent through the complete length of optical fiber from both directions and measurement correction is facilitated. However, the double-ended configuration requires that a continuous optical fiber extend down into a wellbore for the desired interval to be sensed, turnaround, and return to the surface.
Attempts have been made to create turnarounds that route the optical fiber back to the surface. In one example, the turnaround has been formed with a metal tube doubled back on itself with both ends connected to additional tubing. The optical fiber is then routed through the tubing. This technique, however, requires many tubing connections that reduce system reliability while increasing deployment time. Many applications also are subject to space constraints which can create problems in properly controlling the bend of the optical fiber when routed through a turnaround. Exceeding the minimum bend radius of an optical fiber increases optical attenuation and can ultimately result in fiber breakage.


A method of forming a ring gear from a ring blank includes providing a mandrel having a central axis and an outer annular forming surface. The outer annular forming surface defines a plurality of forming elements having a forming element axis offset from the central axis of the mandrel. The ring blank has a ring axis and is placed over the mandrel generally aligning the central axis of the mandrel with the ring axis of the ring blank. A roll is provided having a roll axis that is generally parallel with the element axis. The roll is forced radially inwardly while circumscribing the central axis. The roll pivots around the roll axis deforming the ring blank radially inwardly forming teeth on an inner surface of the ring blank that coaxial with the element axis and offset from the mandrel axis.

This invention relates generally to methods of forming a ring gear. More specifically, this invention relates to methods of forming a ring gear having internal teeth without the use of machining operations.
Gears are widely used in the mechanical arts to transfer motive force between mechanical components. The gear typically includes gear teeth that engage teeth formed on a cooperable gear or mechanical device to transfer motive force between the two elements. Because the mechanical forces are substantial upon each of the gear teeth, a precise dimensional configuration or profile is required to provide a uniform engagement. This is particularly necessary for gears used in automotive transmissions. To achieve precise dimensional configuration, milling, broaching, and machining operations are generally performed on a gear blank to achieve necessary gear teeth profiles. Generally, teeth formations may be formed in the gear blank and then a subsequent machining operation is performed to provide precise dimensional characteristics necessary to withstand the high loads required of complex motive operations used, for example, in automotive transmissions.
Attempts have been made to cold work or flow form gear teeth profiles in simple gears starting from a blank without the use of additional machining operations. While flow forming and cold working have shown promise in eliminating the necessary machining operations, forming defects are prevalent, have heretofore reduced the ability to use gears having teeth formed only by cold working or flow forming in transmission operations. For example, a gear having angular or slightly helical teeth not parallel to a ring axis that have been formed by cold working or flow forming is known to have inconsistencies resulting from not fully filling mandrel formation elements used to form the gear teeth. Inconsistent forming of the gear teeth in a cold working or flow forming process results in mechanical failures in devices in which the gears are used. Thus, it has been necessary to machine gear teeth used in high speed high torque operations.
Therefore, it would be desirable to provide a method of forming defect-free gear teeth on a gear blank that does not require a secondary machining operation, yet enables the resultant gear to be used in a high speed high torque mechanical device.


At least one reinforcing rubber layer is provided in the part of each of two side wall portions which is on the outer side of a carcass layer. The outer circumferential end portions of the reinforcing rubber layers extend to positions in which they are disposed between the end portions of the innermost belt layer and the corresponding portions of the carcass layer, while the inner circumferential end portions of these rubber layers extend inward in the radial direction of the tire so as to overlap the bead fillers in positions on the outer sides of the end portions of the carcass layer in the widthwise direction of the tire. A 100% modulus at 100.degree. C. of the rubber constituting the reinforcing rubber layers is not higher than that of the rubber of the belt layers, and a dynamic elastic modulus at 20.degree. C. of the former rubber in the range of 10-40 MPa. The thickness of the portions of the reinforcing rubber layers which are between the edges of the innermost belt layer and the outer circumferential ends of the bead fillers is set securely to not less than 1.00 mm, and the thickness of the parts of the side wall portions which are on the tire outer sides of the reinforcing rubber layers also not less than 1.00 mm.

This invention relates to a pneumatic tire, and more particularly to a pneumatic tire for, especially, a passenger car, which tire is capable of improving the steering stability thereof while maintaining the durability of belt layers at a level equal to that of the durability of a belt layer in a conventional pneumatic tire, without causing an increase in the weight of the tire.
Conventional pneumatic tires for a passenger car include, for example, a tire shown in FIG. 3. In this pneumatic tire, belt edge cushion rubber layers 14 are disposed between both end portions of an innermost belt layer 12a out of a plurality of belt layers 12 buried in a tread portion 11 and a carcass layer 13. Second fillers 19 are provided the parts of side wall portions 18 which are on the outer sides of both end portions 13a of the carcass layer 13 which extend into the radially outer portions of the tire. The end portions 13a are folded from the inner side of the tire to the outer side thereof around bead cores 16 buried in left and right bead portions 15, in such a manner that the folded parts of the carcass sandwich bead fillers 17 joined to outer circumferences of the bead cores 16. The second fillers 19 are provided so that inner circumferential portions of the second fillers 19 overlap the bead fillers 17 in the widthwise direction of the tire.
The belt edge cushion rubber layers 14 are provided to lessen the stress in the edges of the belt layers and improve the durability of the belt edge portions. The second fillers 19 are provided to heighten the rigidity (especially, the rigidity thereof in the circumferential direction of the tire) of the side wall portions 18 and improve steering stability. The belt edge cushion rubber layers 14 and second fillers 19 are generally formed of different kinds of rubber due to their different purposes.
Since it has become necessary in recent years that a vehicle has a higher performance and secures a sufficiently high safety, a pneumatic tire of the above-described construction must have a higher steering stability. Moreover, in order to follow the tendency in recent years for a vehicle to have decreased weight, it has been strongly demanded that the steering stability of a tire be improved with the durability of a belt layers being maintained at a level equal to that of the durability thereof in a conventional tire, without causing an increase of the weight of the tire.

Pneumatic tire with sidewall reinforcing rubber layer


Systems and methods having front end filters for data links for improved tracking of moving objects are disclosed. In one embodiment, a method includes sensing at least one characteristic of a moveable object using a sensor of an acquisition system, and sensing at least one characteristic of the moveable object using an auxiliary sensor. A data link update is transmitted from the auxiliary sensor to the acquisition system, and the data link update is conditioned to provide composite likelihood. The conditioning includes differencing the data link update and at least one predicted characteristic of the moveable object to produce at least one residual (e.g. using a plurality of Kalman filters). A viewing direction of the sensor may be adjusted based at least in part on the composite likelihood. In another embodiment, residuals are projected along sensor line of sight to form a multi-modal non-Gaussian composite likelihood.

In some applications, sensors or cameras positioned on unmanned aerial vehicles (UAVs) or other airborne platforms may be used to track objects moving on the ground. Such systems may be used in civil applications, such as tracking vehicles by law enforcement and other governmental authorities, or in military applications, such as tracking mobile missiles or armored vehicles by military and intelligence organizations. Examples of prior art UAV-based systems include those systems disclosed, for example, in U.S. Pat. No. 6,712,312 B1 issued to Kucik, U.S. Pat. No. 5,575,438 issued to McGonigle et al., and U.S. Pat. No. 3,778,007 issued to Kearney et al.
In general, as an object moves along the ground, a tracking sensor on the UAV or other airborne platform (e.g. missile) may be steered to prevent the moving object from disappearing from the sensor's field of view. Updates on the position (and velocity) of the moving object may be transmitted to the UAV by a third party observer (or support system) to enable an on-board system to issue pointing commands to steer the tracking sensor to continue tracking the moving object. These updates are generally referred to as "data link updates." Examples of third party observers include an Intelligent Surveillance and Reconnaissance (ISR) platform and a ground observer with a portable target designation system.
The data link updates of existing third party observer systems usually have large measurement uncertainties. Unless special arrangements are made to improve the accuracy of these data link updates, direct use of existing data link data without any filtering may cause the on-board sensor to abruptly transition from one look angle to another when a data link update occurs. Since a sensor tracker is designed to track a moving object within a relatively stable scene, the sensor may lose track of a moving object when the scene changes abruptly.
Some on-board systems feed the data link updates to a Kalman filter to estimate and predict the path the moving objects are taking, and thus provide a smoother pointing command. A Kalman filter is typically characterized by statistical models of data link updates and process noise. The Kalman filtering process involves an iterative algorithm that requires several data link updates for its output to converge if the selected uncertainty models match the true statistics. If the statistical information about the data link update error and process noise model does not match the true statistics, the Kalman filter will either oscillate or diverge, resulting in the on-board system being unable to properly steer the sensor to track the moving object. Existing methods of filtering (e.g. adaptive Kalman filtering, or mode switching Kalman filtering) undesirably require a relatively large number of data link updates for the iterative process to converge and thus provide smooth sensor pointing commands to adequately prevent oscillation or divergence of the on-board tracking system. Therefore, novel systems and methods which provide stable sensor pointing commands using fewer, more sporadic data link updates, and using data link updates having relatively large statistical variability, such as those generated by a ground operator with a portable target designation system and existing legacy surveillance systems, would have utility.

Methods and systems for data link front end filters for sporadic updates


A well system and method including applying suction to a wellhead housing outlet (8) to divert the flow of subterranean gas from flowing through a gas conduit through the wellhead housing (4). An operation can then safely be performed on a component (e.g. removing a hanger) of the wellhead apparatus. Well gas can be diverted to a flare system (200). Suction can be applied by a venturi system including eductors (104, 106). The method may include opening the gas conduit outlet once a pressure sensed at the conduit outlet is negative. Suction may also be applied to an upper outlet (14).

Operations on oil and gas wells need to be performed at regular intervals. Such well operations may include operations at or adjacent a wellhead, in which it may be necessary to remove or replace components of the wellhead (such as a hanger), equipment mounted relative to the wellhead such as the blowout preventer (BOP), or to complete the well. In many of these well operations, it is necessary to open the conduit between the well bore and the atmosphere. To safely open this conduit the flow of gas out of the well must be controlled (especially for gas wells), otherwise maintenance operations would be performed in the presence of a flammable gas which would be extremely dangerous. To the inventor's knowledge the only previous viable method for controlling the gas flowing out of an open well is to kill the well.
Typically, oil and gas wells are killed by filling the well with fluid (especially water). In this process, the hydrostatic pressure of the fluid in the well counteracts the downhole pressure of the gas or oil, which prevents flammable gas from escaping from the well bore to the atmosphere. After the well operation is complete, the fluid is pumped out of the well and the well is ready for re-use. However, this process has many disadvantages.
First, it takes time to fill a well with fluid, and time to pump the fluid out of the well after the well operation is complete. Financially, it is best for a well to be non-operational for the shortest possible time.
Secondly, rock surrounding the well bore may be porous to water (i.e. an aquifer) or non-porous to water (i.e. an aquitard). If aquifers are present, then after the well bore is filled with fluid, the fluid may drain through the aquifers. Consequently, it is necessary to monitor the fluid levels in the killed well, and to top up the fluid in the well when necessary. In some cases, fluid may drain through aquifers to the extent that the well cannot be killed. In general, a well becomes harder to kill over time.
Thirdly, fluids such as water may interact with subsurface earth and rocks and affect the structure of the well formation. For example, some clays will swell in the presence of water which can alter the structure of the formation. Water can also dissolve rocks/soils in the formation, possibly resulting in collapse of some structures within the formation or other adverse effects.
Fourthly, when an operator seeks to pump fluid out of the well it may not be possible to pump all fluid out of the well. The fluid left down the well after the well operation is complete may block or impede the flow of gases (for example) from the well when the well is again in use.
Fifthly, it can be necessary to pump large volumes of fluid into a well to kill the well. After this fluid is pumped out, it generally must be treated before disposal. This treatment step incurs costs.
Sixthly, the introduction of fluid into a well can stimulate microbial growth, contributing to biofouling within the well.

Method and system for controlling gas flow

Well Equipment Solutions Holdings Pty Ltd


System and apparatus for automatically stacking trays involve receiving trays on a receiving platform, detecting the arrival of the tray on the platform, and synchronously displacing the tray to a moveable tray cart located in a tray stacking area of a stacking tower. An automated tray sliding mechanism displaces the tray to the stacking area upon detection of the tray at the receiving platform. Trays displaced in the stacking area of a lower section of a stacking tower form a tray stack. A stack elevator of the tower engages and elevates the tray stack providing a space beneath the stack allowing the next incoming tray to be displaced into the stacking area and assume the provided space beneath the tray stack, the incoming tray thereby assuming the lowermost position in the tray stack. Trays are added to the lowermost position in the stack until the stack height reaches a predetermined height and is removed from the stacking area.

Automated machinery and robotics have come to play an integral role in industry, allowing production lines to proceed more quickly, efficiently, and with increasing safety to laborers within the plant. Production line automation often results in machines assuming those steps that are either dangerous or too demanding for human workers, or that require repetitious routines.
Some automated plants utilize carriers to aid in transporting the plants products from one point in the production line to another. Trays, bowls, and boxes have been employed, carrying goods. The carriers have also doubled as packaging for manufactured goods passed into the marketplace. Food processing plants have also made use of such carriers, with such products as baked, frozen, and canned goods.
Some plants stack product carriers (or collectively "trays") at points within the production and delivery process. Automated stacking machinery exists that allows trays to be stacked from conveyor assembly to build a stack built from the top down—that is, new trays are added to the top of the stack, until the stack reaches a height nearing that of the conveyor. As the stack grows, conventional stacking machinery requires the conveyors and other stacking assemblies to be elevated off the ground to allow for the stack to be built in its downwardly, progressing orientation, beneath the assemblies. These elevated assemblies often make monitoring and maintenance of the stacking machinery difficult and expensive. Additionally, faults and breakdowns with conventional stacking machinery can result in stoppages to the entire assembly line, resulting in costly production delays, lost profit, and man-hours.


Methods, systems, and apparatus include computer programs encoded on a computer-readable storage medium, and include a method for managing and processing receipt information including identifying a user associated with a transaction; receiving a receipt for the transaction from a merchant system or a payment source used to fund the transaction; logging the receipt in a database associated with the user; providing an acknowledgement to an entity associated with the transaction and providing a notification of the transaction to a device associated with the user.

This specification relates to electronic transactions.
Customers can use point-of-sale (POS), online ecommerce, or other systems to initiate transactions, e.g., at brick-and-mortar locations or other locations. A transaction can occur, for example, when a user makes a purchase of goods (e.g., products) or services (e.g., rentals). Each transaction can involve multiple parties, including at least the seller and the buyer. Transactions can also include or be associated with documents such as receipts, acknowledgements, notifications, bills, reports and any other artifacts of commerce. Electronic documents can be produced automatically, such as at a first system, and provided to other systems over the Internet. Some documents can be meant for storage, e.g., to provide historical information and/or for reporting. Other documents may be viewed, stored and/or printed by the user using a mobile or non-mobile device.

Automatic receipt logging and notifications for transactions


An image of a preselected subject is photographed by a camera and is recorded on a reversal film, and a film image thus recorded is read by a scanner and is stored in a storing medium. Data of a photographic processing control image prepared by computer graphics is stored in the storing medium, and a composite image of the image of the subject and the control image is prepared. The image data of a subject portion of the composite image and the image data of a control image portion of the composite image are independently corrected, then the composite image with the corrected image data is recorded on the reversal film, and then the composite image recorded on the reversal film is printed with a negative film interposed therebetween. These operations are repeated until respective subject images of the print obtained by the composite image and of a print obtained by photographing the subject have substantially the same quality and the density and color balance of the control image portion become proper. By using the composite image recorded on the reversal film when these subject images have substantially the same quality and the density and color balance become proper, a photographic processing control tool is prepared.

1. Field of the Invention
The present invention relates to a method for preparing a photographic processing control tool, and particularly to a method for preparing a photographic processing control tool which is suitable for use in setting of an exposure condition and in checking the development properties of an automatic printer or a printer processor having the function of automatically controlling an exposure amount and printing an image of a photographic film, which is a silver salt photographic recording medium, onto a photographic printing paper which is a silver salt photographic recording medium.
2. Description of the Related Art
Generally, in an automatic printer (or a printer processor having a function of development processing) in which an image recorded on a color negative film is printed onto a color photographic printing paper so that a positive image is obtained, the amount of exposure of light for printing is controlled on the basis of the following formula (1): EQU log Fi=Ki+Di (1)
where Fi is an amount of exposure of light for printing, Ki is a constant determined from combination of the automatic printer with a photographic printing paper, Di is the light accumulated transmission density (LATD) of a negative image, and i is any of R(red), G(green) and B(blue) light.
In order to constantly obtain a color print of good quality by using the automatic printer, it is necessary to effect development processing properly and to set an exposure condition of the automatic printer correctly. The automatic printer has a function (i.e., slope control function) of correcting its processing operations so that density and color balance of a finished print become identical with each other irrespective of the density of a negative film (under-exposure, normal-exposure, and over-exposure negatives). In order to adjust the slope control function to set the exposure condition, a so-called Bull's-eye which is a kind of control negative is generally used. The Bull's-eye is prepared in such a manner that a portion corresponding to a negative with a gray-colored subject photographed thereon and a portion corresponding to a negative with a yellowish green-colored subject photographed thereon around the portion corresponding to the negative of the gray-colored subject photographed are exposed.
In the Bull's-eye, a portion corresponding to a circular gray-colored subject is simply formed in a central portion thereof. As a result, there is a problem in that the relationship between that subject and subjects to be printed is not clear.
In order to solve this problem, there is disclosed, in JP-A-5-506733, a method for preparing a control tool of a second-generation camera original using a digitally-prepared transparency photograph which shows an actual scene. In this method, a preselected scene and a first image including a subject are photographed on a first photographic recording medium and a second image indicating photographic processing control information is photographed on a second photographic recording medium. Next, the first image is converted into a first numerical image and the second image is converted into a second numerical image. These numerical images are recorded on a primary digital image data metric in a digital image data base. Subsequently, composite digital image data is prepared by digitally inserting the second numerical image in the first numerical image and at least one parameter of the composite image is selectively adjusted. Further, the composite image is recorded on the photographic recording medium digitally by using a digital output recording medium, the composite image recorded on the photographic recording medium is photographed, the composite image photograph thus obtained is subjected to development processing, and a control tool is thereby obtained.
However, in the above-described prior art method, after the second image representing photographic processing control information has been photographed by a camera, it is photo-numerically converted into a numerical image. Accordingly, two processes for photographing and numeric representation are needed and the time and process involved in preparation of the tool is thereby increased.
Further, since the automatic printer or printer processor has a function of photometrically measuring the negative image to automatically control an amount of exposure, different subjects have different amounts of exposure. Accordingly, the density of photographic processing control information of the prepared print varies in accordance with a change of the subject. However, in the prior art, at least one parameter of the composite image is selectively adjusted and the image of the subject and the photographic processing control information are adjusted at the same time. As a result, when adjustment is made depending on the subject, adjustment of the subject image affects the photographic processing control information on the print, and when adjustment is made depending on the photographic processing control information, adjustment of the photographic processing control information affects the subject image on the print. Accordingly, there exists a problem in that concurrent adjustment of the subject and the photographic processing control information by the parameter leads to much time and process involved in preparation of the tool.
The present invention has been devised to overcome the above-described problems and it is an object of the present invention to provide a method for preparing a photographic processing control tool which allows preparation of a photographic processing control tool by using a simple structure without requiring any time and trouble.

Method and apparatus for preparing photographic processing control tool


A nacelle-mountable lift system for mounting and dismounting a rotor blade of a wind turbine involves a jib crane mountable on the nacelle and a blade sheath. The blade sheath is connectable to the hook of the jib crane by lines attachable to the top end of the sheath. The holder is raiseable and lowerable by a winch mounted on the crane to raise and lower the sheath with the rotor blade retained therein when the rotor blade is disconnected from the hub or to raise and lower the sheath to retain the rotor blade in or release the rotor blade from the sheath when the rotor blade is connected to the hub.

Wind turbines require periodic maintenance to remain operable. Due to the extreme height at which many wind turbines operate, maintaining and/or replacing turbine parts becomes problematic. For reasons of safety and practicality, turbine parts are generally lowered to ground level for maintenance and/or replacement. Typically, a crane is used to lower (and then re-raise) the parts to be maintained or replaced. However, existing nacelle-mounted cranes are insufficient for lifting and lowering very heavy parts of the wind turbine, such as rotor, blades and other very heavy parts of the wind turbine.
When erecting and de-erecting a rotor blade on a hub of a wind turbine, current state-of-the-art procedure involves using a sheave system mounted on the hub together with a ground-based tailing crane for raising and lowering the rotor blade. Such systems require the sheave system to be installed on-site, which is time-consuming and hazardous. Further, the sheave system must be uninstalled and re-installed if multiple rotor blades are to be erected and/or de-erected from the hub.
There have been nacelle-mounted cranes developed in the prior art specifically adapted for maintenance of various nacelle components. However, prior art nacelle-mounted cranes generally suffer from a lack of sufficient lifting capacity and are improperly positioned to erect and de-erect rotor blades. Accordingly, rotor blades are erected and de-erected by the aforementioned state-of-the-art procedure.
There remains a need for a nacelle-mounted crane that is capable of lifting and lowering a rotor blade and other very heavy parts of a wind turbine, such as a generator.

Nacelle-mounted lift system for wind turbine


A portable radio apparatus has a housing containing electronic circuits, a pair of antennas which are each retractable, and a gear mechanism which links the antennas through a predetermined number of gear wheels so that an extending and retracting action of one antenna is transmitted to the other antenna. The gear mechanism includes a pair of racks provided on the antennas, respectively, and a gear assembly including the predetermined number of gear wheels which are meshed in series, both end gear wheels of the gear assembly engaging with the racks, respectively.

1. Field of the Invention
The present invention generally relates to a portable radio apparatus having multiple antennas and, in particular, to the antenna extending and retracting mechanism of a portable radio apparatus.
2. Description of the Related Art
In a portable radio apparatus, spatial diversity can be implemented using multiple antennas. Some radio apparatus are provided with a pair of antennas and others with a retractable antenna and a built-in antenna incorporated in the housing thereof. In the case of the radio apparatus having a pair of antennas, it is preferable that these two antennas are mechanically linked so as to be simultaneously extended and retracted. Such an antenna extending and retracting mechanism has been disclosed in Japanese Patent Unexamined Publication No. 4-330830, as shown in FIG. 1.
Referring to FIG. 1, two retractable antennas 11 and 12 providing spatial diversity are implemented in the body 10 of a radio telephone apparatus. These two antennas 11 and 12 are mechanically linked through two cords 15 riding on two pulleys 13 and 14, respectively, so that they are simultaneously extended and retracted in opposite directions.
However, such a cord-and-pulley arrangement is complicated and needs rather large mounting space within the housing, resulting in the reduced space for implementing electronic devices. Therefore, according to the conventional mechanism, it is difficult to reduce the size and weight of the portable radio apparatus.


An audio processor, apparatus, and method use physical speakers to emulate one or more additional speakers. The physical speakers produce sounds that, from a listener's perspective, appear to come from at least one direction where a physical speaker is not present. Any number of additional speakers can be virtualized, such as three or five speakers that allow two speakers to emulate a 5.1 audio system.

Multi-channel sound systems have become increasingly popular in recent years. While older sound systems often included two speakers placed in front of a listener, multi-channel systems typically use more than two speakers. As an example, in a 5.1 audio system, five speakers and a subwoofer are placed around the listener. In this type of audio system, one speaker is typically placed directly in front of the listener, two speakers in front and to the sides of the listener, and two speakers to the sides and possibly behind the listener. These multi-channel systems typically produce more realistic sound effects, such as more realistic surround sound playback during a movie.
Despite the popularity of these multi-channel systems, many people continue to use conventional two-speaker systems. The use of two speakers in an audio system typically limits or prevents the audio system from producing more realistic sounds using the speakers.

Apparatus and method for rendering audio information to virtualize speakers in an audio system

STMicroelectronics Asia Pacific PTE, Ltd.


Laser displacement meter for measuring a displacement of an object such as a moving distance, a moving angle, and a moving speed. The meter has a generator circuit for generating a displacement signal; another generator circuit for generating a first signal which corresponds to R sin.theta. value of the displacement signal, and a second signal which corresponds to R cos.theta. value of the displacement signal (R represents an amplitude, .theta. represents a phase of the displacement signal); a memory for storing a displacement value being defined by the first signal and the second signal where .theta. is between 0 and 2.pi.; a circuit for transferring a position signal corresponding to the displacement value from the memory according to the first signal and the second signal; a counter for counting a number, being defined as dividing .theta. by 2.pi., corresponding to the displacement signal and for determining the displacement of the object according to the counted number and the position signal.

The present invention relates to a displacement meter such as a laser length measuring apparatus used for measurement of a length, displacement and velocity, a linear encoder and a rotary encoder, and more particularly, to a displacement meter wherein electric signals varying with R sin.theta. and R cos.theta. (where, R represents an amplitude .theta.=2.pi..alpha./S, S is a predetermined frequency) are obtained from .alpha. that is a distance of movement in one direction of a movable object and these two types of signals give numerical value of .theta..
For example, a laser length measuring apparatus of an interference fringes counting type, as shown in FIG. 10 and as disclosed on pages 107-108 of "Optical and Electro-optical Engineering Contact" Vol. 26, No. 2 (1988), is one of the above-described displacement meter.
In the laser length measuring apparatus mentioned above, a linearly polarized beam with a wavelength of .lambda. from stabilized laser 101 is split by beam splitter 102 into a path of a reference beam having .lambda./8 plate 103 and fixed corner cube 104 and a path of a length measuring beam having movable fixed corner cube 105. When the reference beam split in the path of a reference beam passes through the .lambda./8 plate twice, the reference beam is converted to a circularly polarized beam. The reference beam that is a circularly polarized beam and the length measuring beam that is a linearly polarized beam and is split in the path of a length measuring beam are combined together again by beam splitter 102 and then divided into two. One of the divided two beams is further divided into two by polarized beam splitter 106 so that the length measuring beam may be two divided beams each inclining by 45.degree. against the polarization plane of the length measuring beam, thus three types of divided beams are obtained. These three types of divided beams, when they pass through filter 107 and polarization plate 108 respectively, are converted to three types of interference beams whose phases interfered by the movement in one direction of movable corner cube 105 are deviated by 90.degree. in succession. When each of these three types of interference beams enters detecting unit 109, such as a photodiode, they are converted to three types of electric signals whose phases are deviated by 90.degree. from each other. After the three types of electric signals are amplified by calculation amplifier 110, wherein the amplitude and the center of amplitude of each electric signal are aligned, they are grouped into two groups each having two neighboring electric signals whose phases are deviated by 90.degree.. When these two groups of electric signals enter calculation amplifier 111, wherein calculation of sin (x - y) is made, electric signals which vary with R sin.theta. and R cos.theta. (where, R represents an amplitude, .theta.=2.pi. (Lm-Lr).lambda., Lr is a certain length of a reference beam path, Lm is a length of a measuring beam path changing by 2.alpha. with a movement distance .alpha. in one direction of movable corner cube 105, namely a predetermined frequency S=.lambda./2) and have phases deviated by 90.degree. are obtained. Since these electric signals are obtained from the difference of neighboring signals of three kinds of interference fringes signals, as deviated by 90.degree. successively in terms of a phase, outer disturbance, such as intensity variation of laser beam, is canceled and the center of signal level is constantly fixed. Thus an error of counting interference fringes is reduced and measurement with high accuracy can be realized. By inputting both electric signals mentioned above in signal processing circuit 112, wherein a comparison circuit calculating with a counter by obtaining pulse signals from both electric signals, a differentiating circuit, a waveform shaping circuit, an OR circuit and a counting circuit composed of a pulse counter are employed. Alternatively, in signal processing circuit 112 composed of a digital calculation circuit which includes A/D converter and conducts calculation of ##EQU1## and of a discrimination circuit that obtains logically the direction of .theta. change from both electric signals, .theta., namely .alpha. and the direction of up-counting/down-counting, or Lm is obtained.
FIG. 2 shows the relation between R and .theta., which indicates lissajour's figure of R sin.theta. and R cos.theta. having 90.degree. phase difference.
Even in the displacement meter, such as a magnetic or a optical rotary encoder or linear encoder shown on pages 114-120 of National Technical Report Vol. 36, No. 2, April issued in 1990, as well as in an interference fringes counting laser length measuring apparatus or a heterodyne interferometry length measuring apparatus employing two-frequency laser to be sure, and without limiting to the above-described laser length measuring apparatus, an angle of rotation and an amount of a linear displacement are measured by obtaining output signals of R sin.theta. and R cos.theta. and by obtaining .theta. by processing the above-mentioned signals with signal processing circuit 112 in the same way.
The above-mentioned signal processing circuit 112 employing a counter circuit requires comparison circuits in quantity of m, differentiating circuits in quantity of 2 m and waveform shaping circuit for each of the signals for the purpose of obtaining .theta. in an accuracy of .pi./2 m. Therefore, circuits tend to be complex in structure and thereby high in cost. Further, and it is difficult to practically to obtain .theta. in an accuracy as high as .pi./2 m, which has been a problem. By contrast, the aforesaid signal processing circuit 112 employing a digital calculation circuit can obtain .theta. in a high accuracy. However, in order to calculate equations (1) and (2) at high speed, even when a MC 68020 CPU is driven at 20 MHz, a high speed memory that can follow with non-wait is provided, and a high speed calculation element of MC68882 is used, not less than 10 .mu.sec is required for obtaining the values of .theta. and R, while the total processing speed thereof is compelled to be 0.1 MHz or less by a digital calculation circuit speed, which has been a problem. In addition, in the case of an A/D converter that outputs offset binary, the central value of an amplitude of R sin.theta. and R cos.theta. has an offset value D. Therefore, the calculation is to be conducted not for equations (1) and (2), but for equations (3) and (4) shown below, which means that the calculation speed is compelled to be even slower. ##EQU2##
Under the background mentioned above, an idea occurred to the inventors of the present invention. According to the idea, if the signals of R sin.theta. and R cos.theta. are used, without being subjected to the calculation processing on a real time basis for obtaining .theta., but rather as a reading signal for reading the value of relevant .theta. from a memory wherein various values of .theta. corresponding to various groups of R sin.theta. and R cos.theta. are stored in advance. As such, the value of .theta. in a high accuracy would be obtained at high speed, and the signal processing circuit would be capable of being inexpensive and compact in structure. From the idea, the inventors have devised a displacement meter wherein the signals obtained from R sin.theta. and R cos.theta. through the digital conversion thereof are used as a reading signal for reading the relevant .THETA. value from a .THETA. memory, wherein various .THETA. values (where, .THETA. value is a digital value of .THETA. in 0 .ltoreq..THETA.=.theta.-2n.pi.<2.pi., and n is a counted number described later) corresponding to various groups of both digital signals are stored in advance. The value of n is obtained by counting the frequencies of changes of .THETA. values from increase to decrease or from decrease to increase, thus the value of .theta. can be obtained from .THETA. value and n. With the displacement meter of the invention it is possible to obtain the value of .theta. in a phase resolution of 2.pi./256 easily at the speed of 10 MHz or more.
However, when a conventional counting means wherein zero crossing detection in an analog circuit is conducted on a digital basis for counting is used as a means of up/down discrimination counting of .THETA. for counting the number of n, it is impossible to count unless .THETA. becomes zero each time. Therefore, when .THETA. is not the sampling speed that changes by 1 LSB each time, 0 is sometimes skipped and not counted, and thereby the changing speed of .alpha. is limited to be low, which has been a problem.
As such, the first object of the invention is to provide a displacement meter wherein the above-described problems have been solved and counting is conducted correctly and the accurate n can be obtained even when .THETA. does not become zero each time, and therefore, the value of .theta. in high accuracy can be obtained at high speed despite the high changing speed of .alpha..
Further, a heterodyne interferometry laser length measuring apparatus in FIG. 16 can be used as a movable measuring apparatus wherein .alpha. signals showing the movement distance can be obtained from both electrical signals obtained through photo-electric conversion of measurement interference beams and electrical signals obtained through photo-electric conversion of two-frequency laser source beams.
In the movement measuring apparatus, after a laser beam having frequencies of f.sub.1 and f.sub.2 from two-frequency laser 1, wherein two-frequency laser is obtained by the use of Zeeman effect, the laser beam or an acousto-optical effect is divided by polarization beam splitter 2. The laser beam having the frequency of fl is reflected on movable mirror 3 (frequency of reflected beam is f.sub.1 .+-..DELTA.f.sub.1, where with regard to .+-., "+" is for the leftward direction of movable mirror 3 and "-" is for the rightward direction thereof, and .DELTA.f.sub.1 =2v/.lambda..sub.1 where v represents a speed of movable mirror 3 and .lambda..sub.1 is a wavelength for frequency f.sub.1). The laser beam having the frequency of f.sub.2 is reflected on fixed mirror 4, and both reflected beams are combined by polarization beam splitter 2 to be an interference beam. The interference beam enters receiver 5 employing a photoelectric converting element. The receiver 5 inputs electric signals varying under the condition of sin2.pi. (F.sub.2 -F.sub.1 .+-..DELTA.f.sub.1) t (t represents time) into a signal processor, and from two-frequency laser 1, electric signals varying under the condition of sin2.pi. (f.sub.2 -f.sub.1)t are inputted into the signal processor. An 8-bit phase detector on a measurement board with which the transfer of control signals and processing signals is made between the the signal processor and the control unit through a C/I board and multi-pass converts signals from both the receiver 5 and two-frequency laser 1. Thus, from both signals, information concerning the movement direction of movable mirror 3 and movement distance vt=.lambda..sub.1 .DELTA.f.sub.1 .multidot.t/2=.lambda..sub.1 (2.DELTA.f.sub.1 .multidot.t)/4.pi.=.lambda..sub.1 .alpha./4 .pi. are obtained, and position information and speed information of movable mirror 3 against fixed mirror 4 are outputted through 32 bits to a display means or a drive control means for the movable mirror 3 through an accumulator data register.
The movement measuring apparatus employing a laser beam such as the one stated above is capable of obtaining a movement distance of the movable mirror 3 in a high accuracy of one thousandth of .lambda..sub.1 or higher and can be utilized as a movement control device for a moving subject, as shown in FIGS. 17 and 18.
In the movement control device shown in FIG. 17, there is provided on base 6 the driving rail 7 equipped with a driving means, such as a feeding screw, for moving the moving object 8 and a motor. Fixed on the base 6 is the two-frequency laser 1, the polarization beam splitter 2 and the receiver 5. The movable mirror 3 is fixed on the moving object 8 that is moved by the driving rail 7 and the fixed mirror 4 is fixed on one end of the driving rail 7. Information concerning the position and speed of the movable mirror 3, namely of the moving object 8 against the fixed mirror 4 are obtained in the same way as that explained in FIG. 16. Based on the information thus obtained, the drive of the motor on the driving rail 7 is controlled. FIG. 18 is a top view showing an example of a lathe wherein a movement control device shown in FIG. 17 is used for movement control of both a tool carriage and a spindle. To be concrete, members in FIG. 18 which are the same as those in FIG. 17 are given the same symbols as in FIG. 17, and 1'-5' and 7'-8' represent the same functions as in 1-5 and 7-8. The moving object 8 is equipped with a tool post on which a cutting tool is clamped, and the moving object 8' is equipped with spindle 9 which rotates the work piece clamped thereon.
Since the movement control device in FIG. 17 employs a laser length measuring apparatus of the differential type shown in FIG. 16, with which relatively stabilized length measuring accuracy can be obtained easily, the movement of the movable mirror 3, namely of the moving object 8 against the fixed mirror 4, can be measured and controlled in a high accuracy as stated above. However, what is required in most cases is an accurate control for the movement of moving object 8, not against the fixed mirror 4, but against the base 6. In the movement control device shown in FIG. 17, there is employed a laser length measuring apparatus that can offer measurement information in high accuracy, and based on the measurement information, the movement of the moving object 8 is controlled accurately. In this case, when a temperature change causes the change in dimensions of the base 6 and driving rail 7, accuracy for the control of movement of the moving object 8 against the base 6 tends to be worse than the dimension change of the base 6. That is, the position of the moving object 8 against the base 6 is further deviated by an amount equivalent to the dimension change caused by the temperature change, even when the position of the moving object 8 from the fixed mirror 4 is as accurate as the measurement information. An example of this is shown in the lathe in FIG. 18. Namely, an amount of the movement in the arrowed direction of the moving object 8 provided with a tool post in FIG. 18 against a vertical plane including, for example, the spindle axis of the headstock, needs to be obtained accurately and an amount of the movement in the arrowed direction of the moving object 8' against a vertical plane including, for example, this side in the figure of the moving object 8, needs also to be obtained accurately. However, the best accuracy in which the aforesaid amount is obtained is only the one that is worse than the dimension change of the base 6. To be concrete, the movement of the movable mirror 3, that is, of the moving object 8 equipped with a tool post against the position of the fixed mirror 4, can easily be measured in accuracy as high as less than 0.1 .mu.m. However, even the position of the moving object 8 located with positioning resolution of less than 0.1 .mu.m can move by 2-3.mu.m from the position of the axis of the spindle 9 when the ambient temperature changes by 1.degree. C. This value of displacement corresponds to one hundred times of the positioning resolution.
The measures for solving the above-described problems include: (1) to provide the fixed mirror 4 on the reference position on the base 6, (2) to use materials free from the dimension change caused by the temperature change for the base 6 and the driving rail 7, or, (3) to control temperature so that the ambient temperature may not be changed. However, the method of the above-mentioned item (1) is impossible because it means that the fixed mirror 4 must be positioned at the location on the vertical plane that includes the axis of a spindle in the headstock 9 and thereby the movable mirror 3 hits the fixed mirror 4 when the moving object 8 moves. Further, the method of (2) is impossible because the materials mentioned in the item (2) are not available, and the method of (3) is also impossible because the object can not be attained unless the temperature change is controlled within a range of .+-.0.01.degree. C.
From the viewpoint mentioned above, there may be considered a method wherein dimension change information is obtained from information of measurement of ambient temperature, information of distances of fixed mirror 4 and base 6, each from the reference position, and information of linear expansion coefficient of the base 6, and further wherein the moving object 8 is controlled in terms of its movement based on measurement information by means of a laser length measuring apparatus and the dimension change information. Even this method, however, can not solve the above-described problems because the dimension change information is nothing but an indirect presumed value.
Further, a movement measuring apparatus employing a laser beam such as the one mentioned above is for measuring the linear movement of a moving object and can not measure rotary movement. Though it can give an average speed of movement calculated from measurement time and a moving distance of a moving object within the measurement time, it can not obtain the momentary moving speed that changes moment by moment. Though it can be used directly for controlling programs as in examples of FIGS. 17 and 18, it can not be used directly for program controlling.
The invention has been devised also for solving the problems in a conventional movement measuring apparatus wherein a laser beam is employed. Its second object is to provide a movement measuring apparatus employing a laser beam which can be used for accurate measurement and control of the movement of a moving object against a base, for measurement and control of rotation for a minute angle of a moving object, for measurement of speed change of a moving object, and for programmed movement control of a moving object.

Displacement meter with stared displacement values


A stage platform assembly including a corner extrusion member for engagement in a box channel member, and a corner securing member for engagement about tongues of the corner extrusion member at the four corners of sections of the box channel member. A stage platform, such as plywood, secures in a protected fashion to the box channel member. Posts or other elevational members can engage in the corner extrusion member for securing sections of the stage platform together. Locks can also be utilized to secure the stage platform assemblies together.

1. Field of the Invention
The present invention pertains to a stage platform assembly, and more particularly, pertains to three extruded members which when joined together, form a stage platform assembly which protectively engages plywood or other suitable material.
2. Description of the Prior Art
Stage platforms in the past have been specially constructed wooden platforms or wooden platforms joined together through an assortment of bolts and nuts or other suitable fastening means. The platform sections have not always been integral and dimensionally accurate with respect to each other. Vertical storage of the two platforms incurred excessive wear and tear along and about the top plywood platform members.
The present invention provides a stage platform assembly which provides rectangles or squares which are rigid and which can be securedly connected with respect to each other. Extruded side members provide for protection of a wood top member.

Stage platform assembly and method of making same


An optical amplifier for amplifying and outputting an input light signal, comprises an optical light amplifier unit (10), a tunable wavelength filter (30), a signal light detection unit, and a control circuit (100). The optical amplifier unit (10) amplifies the input light signal and outputs an amplified light signal. The tunable wavelength filter (30), into which the amplified light signal is inputted and which transmission light wavelength is swept, outputs a filter output signal. The signal light detection unit detects a signal light level of an amplified output component in the amplified light signal in response to said input light signal. The control circuit (100) controls a gain of said optical amplifier unit based on the signal light level. Further, the signal light detection unit of the optical amplifier according to the present invention comprises a peak detection unit (60) and a background light detection unit (70). The peak detection unit (60) detects a peak light level of the filter output signal. The background light detection unit (70) detects a background light level of the filter output signal.

1. Field of the Invention
The present invention relates to an optical amplifier for use in optical communication and optical information processing. Particularly, the present invention relates to an optical amplifier capable of maintaining amplified signal light level to a constant level at high precision.
2. Description of the Related Art
In the long distance optical communication system, it is common to adopt a system for inserting an optical amplifier into an optical fiber transmission system as means for extending a transmission length. In the optical distribution system for distributing a light signal to various locations, an optical amplifier has been widely used for compensating for a distribution loss.
Conventionally, as a light amplifier for directly amplifying a light signal, an optical fiber amplifier using a rare-earth doped optical fiber as an amplifying medium and a semiconductor optical amplifier using stimulated emission phenomenon within a semiconductor device have been well-known. At present, the optical fiber amplifier is commercially well-known.
If such an optical amplifier is used in, for example, an optical transmission equipment, it is required to maintain constant a light signal level in every part of the system for purposes of stabilizing transmission characteristics. Due to this, it is said to be necessary to provide a function of keeping constant the signal light output of the optical amplifier inserted into the transmission path.
Conventionally, as ways to control the signal light output power of the optical amplifier to be constant, there has been proposed a method for monitoring the entire output light power of the optical amplifier and controlling the power to be constant. Generally, however, amplified spontaneous emission as well as an amplified signal light is outputted from the optical amplifier. The ratio of the spontaneous emission to the entire light power varies according to the input light power. The optical amplifier output power monitoring method used in the above-stated control method cannot measure an output signal light level at high precision due to the influence of the spontaneous emission. Accordingly, even if the optical amplifier unit is controlled to make the output light level of the optical amplifier constant, it is difficult to maintain constant the signal light output level. As ways to reduce the influence of spontaneous emission, there has been proposed means for eliminating spontaneous emission using an optical filter. However, the optical filter cannot eliminate a component having the same wavelength as that of the signal light. Due to this, even with such an optical filter, it is impossible to completely avoid the influence of spontaneous emission.
Even in case no signal light is inputted into the optical amplifier unit, spontaneous emission is outputted from the optical amplifier unit and it is impossible to determine whether or not a signal light is present from the result of monitoring the output power of the optical amplifier. Due to this, it is necessary to add means for detecting whether or not a signal light is present to the input of the optical amplifier unit so as to operate the optical amplifier only in case the signal light is inputted. As a result, the number of optical components constituting the optical amplifier increases.

Optical amplifier and optical amplifier gain control method and apparatus


An independent two pump system comprising an implement hydraulic pump and a steering hydraulic pump is described. The system has an inexpensive structure and the capability of preventing a construction machine from engine stalling without impairing fuel economy. When the implement hydraulic pump is actuated with the output of an engine to operate an implement attached to the construction machine, while actuating the steering hydraulic pump with the output of the engine to turn a vehicle body of the machine, the load exerted on the implement is detected and if the detected load is determined to exceed a preset value, the displacement of the steering hydraulic pump is reduced to thereby reduce the load associated with turning of the vehicle body.

In a conventional construction machine such as a bulldozer, the "independent two pump system" is employed to ensure hydraulic power required for carrying out operation of the attached implement such as a blade and ripper and turning of the vehicle body at the same time. In this system, two separate pumps are used, one being an implement hydraulic pump for supplying hydraulic power to the implement, and the other being a steering hydraulic pump for supplying hydraulic power to the steering hydraulic motor.
In this known system, variable displacement hydraulic pumps are used as the implement hydraulic pump and the steering hydraulic pump, for the purpose of preventing possible engine stalling when these pumps are simultaneously operated. By use of such pumps, horse power consumption can be reduced and engine torque rise and the amount of torque required for travelling in the low speed range are set high.
A prior art relating to the present invention is disclosed in Japanese Patent Publication (KOKAI) No. 57-133940 (1982). This publication discloses a construction machine which employs a single motor for operating three hydraulic pumps (two variable displacement pumps and one fixed displacement pump). When this construction machine is not in turning motion, the sum of horse power input to the variable displacement pumps which are not for use in turning operation is set to a value obtained by subtracting a certain amount from the total output horse power of the motor, whereas the discharged fluid of the fixed displacement pump used for turning operation is allowed to join the fluid pressure circuit which is not for turning operation. On the other hand, when the construction machine is in turning motion, the sum of horse power input to the variable displacement pumps not for use in turning operation is first made to be substantially equal to the total output horse power of the motor and is then allowed to decrease as the discharged horse power of the fixed displacement pump for turning operation increases. In this way, the total of horse power input to the three hydraulic pumps is maintained to be substantially constant.
Systems using variable displacement pumps both for the implement hydraulic pump and for the steering hydraulic pump, like the conventional independent two pump system, require an auxiliary machine such as a turbo-charger or after-cooler in order to increase engine torque rise, resulting in poor cost performance and poor fuel economy. Two variable displacement hydraulic pumps complex in structure are essential for the conventional two pump system, and installation of two variable displacement pumps makes the entire system bulky and costly.
The related art disclosed in the publication No. 57-133940 is designed to allow the discharged fluid of the pump for turning operation to join the fluid pressure circuit not for use in turning operation and is therefore inapplicable to construction machines such as described in the invention in which there is a big difference in pressure between the implement hydraulic circuit and the steering hydraulic circuit.
The present invention is directed to overcoming the above problems and the primary object of the invention is therefore to provide a control method and system for a construction machine, which employ the independent two pump system including an implement hydraulic pump and a steering hydraulic pump, the method and system capable of preventing engine stalling with inexpensive system structure and without increasing fuel cost.

Control method and system for construction machine


A panel system for office workstations wherein a display board is removably secured to a hanging bar, The bar has a bracket assembly for selectively and removably hanging it onto a selected surface and has flanges arranged in the bar which may receive the bracket assembly and which removably secure the display board on the hanging bar when the display board is oriented with the flanges in a predetermined position. The display board has a frame defined by top, bottom and side extrusions and corner members joining the extrusions together, utilizing channels arranged in the extrusions, and hangers slideably fixed in the extrusion channels which are adapted to be secured in channels when properly oriented therewith. A tray may also be removably secured in the channels of the display board extrusions in selected removably secured positions.

The panel system embodying the present invention essentially consists of two members, i.e. (1) a display board, such as a writing board, which may comprises a dry erase surface, like melamine, or a bulletin board, which may be a fabric covered surface capable of receiving push pins, or both, and (2) a hanging bar on which multiple or single boards of either or both a writing board and a bulletin board may be removably secured.
Preferably, this hanging bar is sufficiently versatile to be mounted on modular workstation panels or slotted uprights of various standard widths and depths and may be mounted at any height within defined dimensions, as selected by the user. For most installations, only slight variations in the brackets for mounting the bar on a surface need to be made to accommodate the mounting position selected by the user.
Such a bar may also be used for mounting on any wall surface, even one without standard slots, with the use of special brackets, as disclosed herein. The hanging bar embodying the present invention in designed to easily accommodate various kinds of mounting hardware in a stable and effective fashion, with only limited variations in the mounting brackets being necessary to meet the mounting conditions desired.
Such a hanging bar, in association with the hanging hardware on the board, also provides easy means for removably secured mounting of selected boards. Even while providing easy changeover of boards, the hanging bar also provided stable mounting of the boards, in a way that unintended jolting of the board or other related structure will not cause the board to be dislodged unintentionally from the hanging bar. Further, the bar is capable of receiving horizontally arranged insert strips, which may be used for mounting materials suitable for receiving push pins or magnets, or decorative strips to vary the appearance of the hanging bar.
With reference to the display boards, they are constructed to be easily oriented in a selected horizontal or vertical direction, and the orientation may be easily changed. The invention also includes a tray for holding markers, pointers, push pins or similar items; and this tray may be secured to the bottom of the board and easily moved at right angles when the board is reoriented, and the tray has effective means for looking and unlocking it in a selected position. Boards of various colors, textures and configurations are completely interchangeable, without rearranging the hanging bar in any way. In most situations, the hanging bar may be mounted and the boards may be varied in the manner discussed without the use of special tools or training. Slight variations from manufacturer to manufacturer or from one office installation to another installation may be easily made by more manipulation of the parts, without having to substantially rearrange the components responsive to these variations.