To provide a sliding apparatus which may depress a micro slip phenomenon without fail and realize the system with a simple structure and which is less expensive to save a cost and superior in practical use. In a sliding apparatus in which a sliding member (2) is slid relative to a shaft (1), a loading path (3) is provided between the shaft (1) and the sliding member (2), a plurality of rolling member (4) are arranged in the loading path (3) and the rolling members (4) are adapted to roll and move along the loading path (3), a convex portion (5a) and/or a concave portion are provided to at least one rolling member (5) out of rolling members (4) arranged in the loading path (3), a convex portion and/or a concave portion (3a) engaged with the convex portion (5a) and/or the concave portion of the rolling member (5) are provided to the loading path (3), the rolling member (5) is arranged in the loading path (3) in concave and convex engagement with the loading path (3) and a rolling member retainer (6) for retaining the rolling members (4, 5) is provided in the loading path (3).

As shown in FIGS. 1 and 2, a general sliding apparatus is provided in which a sliding member 22 having a substantially inverted U-shaped cross section and having arm portions 22c on the right and left sides of a base portion 22b is fitted on a shaft 21 provided on a base member 29, the sliding member 22 is adapted to be slidable reciprocatingly relative to the shaft 21, a loading path 23 composed of first loading grooves 21a provided on both sides of the shaft 21 and second loading grooves 22a provided, respectively, on inner surfaces of right and left arm portions 22c of the sliding member 22 and confronted with the first loading grooves 21a is provided between the shaft 21 and the sliding member 22, and a plurality of rolling members 24 are arranged at a predetermined interval in the loading path 23 so that the rolling members 24 may be rolled and moved in accordance with the sliding movement of the sliding member 22. Incidentally, in the drawings, reference numeral 26 denotes first loading portion forming member provided on the shaft 21 and reference numeral 27 denotes second loading portion forming member provided on the sliding member 22.
By the way, as described above, the sliding member 22 is slidingly moved relative to the shaft 21 together with the rolling movement of the rolling members 24. However, since when the rolling members 24 collide against each other upon rolling movement, this causes the hindrance of the smooth sliding movement of the sliding member 22 or the generation of noises, rolling member retainers 25 in which rolling member aligning windows 25a are formed in a plate member are arranged in the above-described loading path 23 and the rolling members 24 are arranged in the rolling member aligning windows 25a of the rolling member retainers 25 as shown in FIG. 2, whereby the interval between the adjacent rolling members 24 may be kept constant and the collision of the adjacent rolling members 24 may be prevented.
On the other hand, it is known that, in the conventional sliding apparatus, a phenomenon that a relative position among the shaft 21, the sliding member 22 and the rolling member retainers 25 is gradually displaced in accordance with the reciprocating sliding movement of the sliding member 22, i.e., a so-called "micro slip" phenomenon would occur.
The displacement of the rolling member retainers 25 due to the micro slip phenomenon causes the friction between the rolling member retainers 25 and the rolling members 24. This friction prevents the smooth movement of the sliding members 22 or causes the noises. Furthermore, when the displacement becomes remarkable, the rolling member retainers 25 would be broken to cause a serious damage to the instrument into which the sliding apparatus is incorporated.
Therefore, in order to prevent the above-described micro slip phenomenon, for example, as in Japanese Patent Application Laid-Open No. Hei 11-315831 (hereinafter referred to as Patent Publication 1) as shown in FIGS. 3 and 4 and as in Japanese Patent Application Laid-Open No. Hei 11-315832 (hereinafter referred to as Patent Publication 2) as shown in FIGS. 5 and 6, a disc member 32 having a plurality of convex portions 30 is coupled with a rolling member retainer 25, a plurality of concave portions 31 in concave and convex engagement with the convex portions 30 of the disc member 32 are provided in a loading path 23, the convex and concave engagement mechanism composed of the convex portions 30 and the concave portions 31 is caused to work so that the rolling member retainer 25 is moved along the loading path 23, whereby the above-described displacement of the rolling member retainer 25 may be prevented. However, this is complicated in structure and inferior in durability and worse in maintenance property and it is inevitable to increase the cost.
More specifically, Patent Publications 1 and 2 are directed to the structure where the disc member 32 which is discrete from the rolling members 24 to be coupled with the rolling member retainer 25 is provided in a central portion of the rolling member retainer 25. Since this disc member 32 is not subjected to any load from the loading path 23, the convex and concave engagement relationship of the convex and concave engagement mechanism is loose (that is, the convex and concave engagement is not firmly attained). Thus, it is impossible to completely prevent the micro slip phenomenon.
Also, since the disc member 32 is large in size relative to the rolling members 24, an effective stroke length of the sliding member is short. If this effective stroke length is to be elongated, it is necessary to shorten the length of the rolling member retainer 25 correspondingly, so that the rolling members 24 retained by the rolling member retainer 25 are reduced to cause a problem that the loading capacity is reduced.
Furthermore, since the disc member 32 is adapted to be coupled with the rolling member retainer 25, it is necessary to provide a shaft 33 for pivotally retaining the disc member 32. Since this is usually made of resin, the machining thereof is troublesome in precision and rigidity.
Patent Publication 1: Japanese Patent Application Laid-Open No. Hei 11-315831
Patent Publication 2: Japanese Patent Application Laid-Open No. Hei 11-315832


A discomfort index, S, is calculated with an equation, S=0.3135×(Loudness value)+3.4824×(Tonality value)−3.1460. This equation uses a loudness value and a tonality value, both psychoacoustic parameters obtained from a sound from the image forming apparatus at a location 1.00 m±0.03 m apart from an end of the image forming apparatus. A sound caused at the time of charging an image carrier is improved so that the discomfort index S satisfies S<−0.5.

In recent years, the viewpoint of friendliness to the environment raises concerns on noise problems higher and increases needs to solving the noise problem even for OA machines in offices. Accordingly, sound reduction of OA machines has been intended and actually such the sound reduction has been advanced more than before.
There are several technologies disclosed to solve such the noise problems. For example, JP 9-193506A publication discloses a technology using a noise-masking device which reduces discomfort of noises from a laser beam printer or a copier. The noise-masking device comprises a sound generator which generates a masking sound to mask noises from a drive mechanism that serves on operation as a noise source. The device also comprises a masking sound controller unit which controls and allows the sound generator to generate the masking sound having frequencies within a range that contains major component frequencies of the noises.
However, the technology disclosed in the JP 9-193506A publication has a disadvantage because it adds the masking sound to noisy sounds caused functionally from the body without reducing the noisy sounds, resulting in an elevated noise level. Therefore, some persons may feel rather noisy and more uncomfortable. In addition, the technology requires the use of the sound generator which generates the masking sound and the controller which controls the masking sound to be generated for a limited time period, during which the sounds to be masked are caused. Therefore, the technology also has a disadvantage because it requires, on layout of the machine, an extra space and greatly elevated cost.
Technologies relating to apparatus and methods of evaluating sound quality are also disclosed as described below. For example, JP 10-232163A publication discloses a technology for facilitating of determination on a relation between a noise and the corresponding psychological noisiness. This technology is employed, in an apparatus and method of evaluating sound quality, for evaluating only a "roaring sound" among noises consisting of sounds with many tones from image forming apparatus. The roaring sound is a heavy noise with low-frequency random noises caused from an air flow system, such as an exhausting sound.
JP 10-253440A publication discloses a technology, in an apparatus and method of evaluating sound quality, for evaluating only a "screeching sound" extracted from noises consisting of sounds with many tones from image forming apparatus. The screeching sound is a continuous pure sound caused from a scanner motor or a charger and is recognized noisy.
JP 10-253442A publication discloses a technology, in an apparatus and method of evaluating sound quality, for evaluating only a "friction sound" extracted from noises consisting of sounds with many tones from image forming apparatus. The friction sound is composed of high-frequency random noises caused from slipping of a recording paper.
JP 10-267742A publication discloses a technology, in an apparatus and method of evaluating sound quality, for evaluating only a "whir" extracted from noises consisting of sounds with many tones from image forming apparatus. The whir is composed of pure sounds that have peaks at a plurality of frequencies proximate to a humming from a drive system.
JP 10-267743A publication discloses a technology, in an apparatus and method of evaluating sound quality, for evaluating "smoothness" of a sound extracted from noises consisting of sounds of many tones from image forming apparatus. When there is no pure sound and humming, that is, no projected component is present in a frequency waveform, a person can feel such the sound as a smooth sound. Therefore, it is possible to totally call noisiness felt by a person as "smoothness".
The above conventional technologies in terms of the apparatus and method of evaluating sound quality, however, failed to propose any apparatus and method of improving sound quality on actual products though they propose the methods of evaluating sound quality.
Currently, an acoustic power level (ISO 7779) is generally employed in OA machines as an approach which evaluates a noise. The acoustic power level is a value of acoustic energy produced from an office machine such as a copier and a printer. Accordingly, there may be often no well correlation between the acoustic power level and a human subjective discomfort against the noise. For example, when sounds with the same acoustic power level are heard and compared with each other, a difference in discomfort between them may be found. In addition, even if a sound has a low acoustic power level, a person may feel the sound extremely uncomfortable.
Accordingly, a further improvement on the office environment requires reduction of the acoustic power level of an OA machine as well as progression in improvement on its sound quality. The improvement on the sound quality requires a quantitative measurement of the sound quality to grasp the current situation and a measurement of an improved degree after the improvement. However, the sound quality is not a physical quantity and accordingly can not be measured quantitatively. Namely, when sounds are listened to through ears to compare their qualities with each other, a difference may occur in evaluations according to persons. In addition, an expression can be performed only qualitatively such that "the sound quality was improved a little" or "considerably improved". Unless a quality of a sound can be expressed quantitatively with a physical quantity, even if measures are implemented for improvement on the sound quality, it is impossible to evaluate the effect objectively.
Psychoacoustic parameters are physical quantities employed for evaluating sound quality. Typically, the psychoacoustic parameters include the following (see, for example, The Japan Society of Mechanical Engineering, The 7th Design and Systems Conference, "Direct to innovative leaps in design and systems towards the 21st century!", Nov. 10 to 11, 1997, "Sounds/vibrations and design, colors and design (1)" division, 089B. Characters in brackets denote a unit).                Loudness (sone), Magnitude of audibility        Sharpness (acum), Relatively distributed quantity of high-frequency components        Tonality (tu), Contents of pure components        Roughness (asper), Roughness of sound        Fluctuation strength (vacil), Humming
In addition to the above, such machines are launched that can measure the following psychoacoustic parameters.                Impulsiveness (iu), Impulsive property        Relative approach, Fluctuation feeling
The above psychoacoustic parameters have a trend to indicate an increase in discomfort as either of them increases a quality. Among those, only the loudness is standardized in ISO 532B. As for other psychoacoustic parameters, the same fundamental concept can be applied, however, programs and computations are different from one another due to a unique research according to each measurement instrument maker. Therefore, measured values are slightly different from one another according to maker sin common. It is possible to improve the sound quality through an effort for reducing all of these psychoacoustic parameters.
However, it requires a great effort to prepare measures for all psychoacoustic parameters. Noises caused from OA machines such as copiers and printers are composed of many toned noises due to complexity of their mechanisms. For example, low-frequency heavy sounds, high-frequency screeching sounds and impulsive sounds are caused variably with time from a plurality of sound sources such as motors, recording papers and solenoids.
A person judges these sounds totally and decides whether he/she feels uncomfortable or not. In this case, the person can be considered to weight on a particular part that relates to the discomfort before the decision. In a word, there are psychoacoustic parameters that are greatly effect on the discomfort and psychoacoustic parameters that are less effect on the discomfort, which differ due to tones from machines. For example, in a printer that causes impulsive sounds many times at a high speed, the impulsive sounds are felt the most uncomfortable. On the contrary, in a desktop printer that causes relatively silent sounds at a low speed, as impulsive sounds are caused less, a charging sound caused on AC-charging is felt the most uncomfortable. Thus, uncomfortable parts differ case by case. Accordingly, the low-speed machine and the high-speed machine may have different parts that require improvements on the sound quality. From such the ground, by searching psychoacoustic parameters that have great improvement effects on discomfort and improving the psychoacoustic parameters to improve sound quality efficiently, the above effort can be reduced.
Accordingly, by combining psychoacoustic parameters that have great improvement effects on discomfort, then weighting the psychoacoustic parameters to derive a sound quality evaluative equation, and computing a subjective evaluation value against the discomfort using the sound quality evaluative equation, it is possible to evaluate the sound quality objectively and improve the sound quality. Further, by deciding, for a subjective evaluation value against discomfort, a degree that can eliminate the discomfort, and providing an image forming apparatus that has sound quality improved below the degree, it is possible to solve the noise-related problems in offices.

Image forming apparatus and method of evaluating sound quality on image forming apparatus


Apparatus and method are provided for obtaining improved measurement and control of the temperature of a semiconductor wafer (W) during processing. The apparatus includes a chuck for holding a wafer during processing, a coolant gas supply (16), and a temperature sensing arrangement for measuring and controlling the temperature of the wafer during processing. A top face of the chuck (22) over which the wafer is positioned, is configured with a plurality of holes (34) into which the coolant gas, such as helium, is admitted at controlled rate and pressure. The coolant gas passes through a narrow space (36) between the top face of the chuck and the underside of the wafer and is evacuated via an exhaust line (30) after being heated to (or nearly to) the temperature of the wafer. Temperature of the now-heated coolant gas is continuously measured by a temperature sensor arrangement which generates a signal controlling the pressure and flow of coolant gas to the wafer. Close control of the temperature of the wafer is thereby maintained continuously at a desired value during processing.

The steps in processing semiconductor wafers into individual integrated circuits (ICs) are well known in the art. In one widely used manufacturing method a semiconductor wafer (typically six or eight inches in diameter) is chemically and photographically processed through a number of steps to produce a multitude of very closely spaced and precisely detailed ICs on the wafer. In such processing, a wafer may be exposed within a reactor to a highly active plasma of special gas or gases in order to etch, by means of reactive ions of the gases, very fine details (lines, zones, etc.) into a top surface of a wafer being processed. The wafer is subsequently cut into individual ICs. This general technology is well known in the art and need not be described further.
A typical IC processing apparatus comprises a reactor in which there is a chamber through which reactive gas or gases are flowed, a support such as a chuck or pedestal for holding one or more wafers in proper position in the chamber to expose a top surface of the wafer to the reactive gas.
By way of example, during etching in a typical plasma etching operation, the reactive ions of the plasma gas chemically react with portions of material on a face of the semiconductor wafer. This process is exothermic and causes some degree of heating of the wafer. The chemical reaction between gas (ions and radicals) and wafer material, on the other hand, is accelerated to some degree by the temperature rise of the wafer. Wafer temperature and the rate of chemical reaction are related to an extent that harmful over-etching (or under-etching) of material over a face of the wafer can easily result if the temperature of the wafer varies too much from a desired value. It is highly desirable therefore that wafer temperature be accurately controlled with respect to a given process [e.g., reactive ion etching (RIE)] since otherwise the IC's being fabricated on the wafer will have electronic characteristics which deviate from their design center more than is desirable.
The problem of temperature rise of a wafer during IC processing is well known. One effective way to control wafer temperature to a desired value is to flow coolant gas (such as helium) at a suitable pressure and flow rate within and through a thin space between the bottom of the wafer and the top of the chuck or pedestal which holds the wafer. However, there are certain difficulties in measuring the temperature of the wafer during processing. To put a temperature probe, such as a thermocouple, in actual contact with the wafer can cause distortion in the temperature distribution over the wafer itself and this in turn affects measurement accuracy as well as the processing of the wafer. On the other hand, remote sensing of the temperature of the wafer by infrared (IR) scanner is complicated by the fact that the wafer, being a thin piece of essentially pure silicon, is transparent to certain wavelengths of infrared light (much as an ordinary glass window is transparent to visible light). An IR sensor therefore "sees" not only the wafer temperature but that of the chuck on which it is mounted and also possibly background temperature of the walls of the reaction chamber within which the wafer is being processed. This makes it necessary to carefully calibrate the IR sensor with respect to the heat emissivity of a wafer being processed as well as that of the chuck and possibly also the inside walls of the reaction chamber.
From the above discussion, it is desirable to provide easy and accurate measurement and control of the temperature of a wafer during processing.

Semiconductor wafer temperature measurement and control thereof using gas temperature measurement


A suspension system is provided comprising at least one ride height valve, when engaged, that allows an air flow to engage a hydraulic control valve such that it initiates either extension or retraction of a hydraulic piston from a cylinder. Extension or retraction of the hydraulic piston causes a booster frame to be bias downwardly or upwardly, respectively. The ride height valve is engaged when a booster axle is at a predetermined distance from the frame.

Canadian Patent No. 2,636,513 to Aspen Custom Trailers, herein incorporated by reference in its entirety, discloses a suspension system for towed vehicles that automatically adjusts for different payloads and road conditions without the need for manual shims used in prior art suspensions. An electronic sensor, in combination with a controller, is employed that measures the ride height and causes the hydraulic cylinder to retract or extend according to the bias needed to maintain the suspension in the preferred ride height range. The controller includes a microprocessor in electrical communication with the sensor and with the hydraulic load biasing mechanism through a control line. However, the reliability of an electronic system is low given the harsh environment these units typically operate in.
United States Patent Application Publication No. 2018/0236839A1 to Superior Synchronized Systems LLC, herein incorporated by reference in its entirety, discloses a system that auto adjusts the shim by utilizing pressure transducers on the trailer and booster air suspension. The system continually monitors and compares the pressure in the load carrying trailer airbag system at a first transducer, and in the add-on-axle trailer airbag system at second transducer. A processor adjusts the shim based on the comparison.


A magnetic gap is provided between a permanent magnet of a rotor and an auxiliary magnet pole portion which is arranged adjacent to the permanent magnet in a peripheral direction. A gradual change in a magnetic flux density distribution of a surface of the rotor is obtained and a cogging torque and a torque pulsation are restrained. By obtaining a reluctance torque according to the auxiliary magnetic pole, a permanent magnet electric rotating machine in which the cogging torque and the torque pulsation are restrained can be obtained and further an electromotive vehicle having the permanent magnet electric rotating machine can be provided.

1. Technical Field
The present invention relates to a permanent magnet electric rotating machine and an electromotive vehicle using a permanent magnet electric rotating machine and in particularly to a permanent magnet electric rotating machine in which permanent magnets are used as a magnetic flux generating means and an electromotive vehicle such as an electric vehicle which uses the permanent magnet electric rotating machine.
2. Prior Art
Up to now as one kind of an electric rotating machine, a permanent magnet electric rotating machine has been used, in which permanent magnets of the permanent magnet electric rotating machine are used as a magnetic field generating means for a rotor.
As a conventional permanent magnet electric rotating machine, there is a known surface magnet structure permanent magnet electric rotating machine, wherein plural permanent magnets of the permanent magnet electric rotating machine are arranged in parallel and fixed on a surface of a rotor and further adjacent permanent magnets are arranged to have a reversed polarity at a peripheral direction.
However, in the above stated surface magnet structure permanent magnet electric rotating machine, during a high speed rotation there is a possibility of the permanent magnet peeling off due to centrifugal force.
A permanent magnet rotor having a permanent magnet embedding structure permanent magnet electric rotating machine is disclosed in Japanese patent laid-open publication No. Hei 5-76,146. Namely, in the above stated permanent magnet rotor, permanent magnets are inserted in and fixed to holes, such holes extend into an interior portion of the rotor in an axial direction.
Further, so as to aim to simplify a structure for a case in which the rotor having the permanent magnet embedding structure of the permanent magnet electric rotating machine is performed to carry out a skew structure, such a permanent magnet structure of the permanent magnet electric rotating machine is disclosed in Japanese patent laid-open publication No. Hei 5-236,687. Namely, in this permanent magnet structure permanent magnet electric rotating machine, a space is formed from an end face of each of the permanent magnets which are installed in an interior portion of a rotor to an outer periphery of the rotor.
However, in the above stated prior art, there is a problem in which an obtaining of a reluctant (reluctance) torque by auxiliary magnetic poles and a reduction in a cogging torque or a torque pulsation are not incompatible. Hereinafter, in this specification, the torque pulsation indicates one combining both the reluctant torque and the cogging torque.
In the permanent magnet embedding structure permanent magnet electric rotating machine, utilizing the rotor member provided between the adjacent permanent magnets as the auxiliary magnetic pole, a composite vector of an armature magnetomotive force of a stator is controlled to direct toward a side of a rotation direction but not to direct toward a central position direction of the auxiliary magnetic pole, as a result, the reluctant torque can be obtained.
This reluctant torque is added to a main torque generated by the permanent magnets and the entire torque of the permanent magnet electric rotating machine can be increased. Therefore, the efficiency of the permanent magnet embedding structure permanent magnet electric rotating machine can be increased.
On the other hand, in the conventional permanent magnet electric rotating machine, since the permanent magnets always generate a magnetic flux regardless of the existence of an electric power supply, the rotor can always receive a force. The force is one which corresponds to a positional relationship between the permanent magnet and a stator's salient pole portion and during the rotation time the above stated force changes in a pulsed manner. This pulsating force appears as the torque pulsation.
This torque pulsation obstructs a smooth rotation of the rotor, thus causing a problem in which a stable operation of the permanent magnet electric rotating machine cannot be obtained.
In the permanent magnet rotor of the permanent magnet electric rotating machine shown in Japanese patent laid-open publication No. Hei 5-76,146, since the rotor has the auxiliary magnetic poles, it is possible to obtain the reluctant torque. However, since a distance formed between the permanent magnet and the auxiliary magnetic pole is minute in the periphery direction, an abrupt change in a magnet flux density distribution appears in the minute distance portion, accordingly the torque pulsation arises.
On the other hand, in the permanent magnet electric rotating machine shown in Japanese patent laid-open publication No. Hei 5-236,687, the space is formed between the adjacent permanent magnets. In this space, an adherence property fill-up member comprised of a non-magnetic body is located.
Accordingly, the magnet flux density distribution between the adjacent permanent magnets is muted, such that it hardly generates the cogging torque or the torque pulsation. However, the above stated space or the fill-up member does not work as the auxiliary magnetic pole, therefore the reluctant torque can not be obtained.

This patent is subject to a terminal disclaimer.

Permanent magnet electric rotating machine and electromotive vehicle using permanent magnet electric rotating machine


An X-ray diagnostic apparatus includes a floor rotating arm which is installed at one end on a floor surface so as to be rotatable around a first rotation axis, a C-arm which is mounted on the other end of the floor rotating arm so as to be rotatable around a second rotation axis, an X-ray tube which is mounted on one end of the C-arm, an X-ray detector which is mounted on the other end of the C-arm, and a bed which has a table top provided to be movable along a longitudinal axis. The bed is placed such that the longitudinal axis is spaced apart from the first rotation axis by a predetermined distance.

1. Field of the Invention
The present invention relates to a C-arm holding apparatus and an X-ray diagnostic apparatus and, more particularly, to a floor type C-arm holding apparatus which holds an X-ray generating unit and an X-ray detecting unit so as to make them face each other, and an X-ray diagnostic apparatus having the C-arm holding apparatus.
2. Description of the Related Art
Medical imaging diagnostic techniques using X-ray diagnostic apparatuses, MRI apparatuses, and X-ray CT apparatuses have rapidly advanced with improvements in computer technology, and have become indispensable to current medical practice.
Recently, X-ray diagnosis has advanced mainly in the field of circulatory organs with improvements in catheter techniques. An X-ray diagnostic apparatus for the diagnosis of circulatory organs generally comprises an X-ray generating unit, an X-ray detecting unit, a holding apparatus which holds the X-ray generating unit and the X-ray detecting unit, a table top, a signal processing unit, a display unit, and the like. The holding apparatus allows X-ray imaging at an optimal position or in an optimal direction by pivoting, rotating, or moving a C-arm or Ceiling-traveling C or Ceiling-mounted arm around a patient (to be referred to as a subject hereinafter).
As a detector used for the X-ray detecting unit of an X-ray diagnostic apparatus, an X-ray film or an I.I. (Image Intensifier) has been used. In an X-ray imaging method using this I.I., X-ray projection data (to be referred to as projection data hereinafter) obtained when X-rays generated by the X-ray generating unit are transmitted through a subject is converted into an optical image by the I.I., and this optical image is displayed on a monitor after being converted into an electrical signal by an X-ray TV camera and digitized. Therefore, the X-ray imaging method using the I.I. allows real-time imaging which is impossible in the film system, and can acquire projection data in the form of digital signals. This makes it possible to perform various kinds of image processing. As a substitute for the above I.I., a flat panel detector comprising a two-dimensional array of detection elements has recently attracted attention. Some of such detectors have already been put into practical use.
FIG. 8 shows a C-arm holding apparatus used for a conventional circulatory organ X-ray diagnostic apparatus. An X-ray generating unit 101 is mounted on one end (lower end) of a C-arm 103 of a C-arm holding apparatus 105, and an X-ray detecting unit 102 comprising, for example, a flat panel detector is mounted on the other end (upper end) of the C-arm 103 so as to face the X-ray generating unit 101. A one-dot dashed line 108 in FIG. 8 represents an imaging central axis (isocenter) which connects the focal point of an X-ray tube in the X-ray generating unit 101 to the center of the flat panel detector of the X-ray detecting unit 102.
The C-arm 103 is held on a stand 105, fixed on a floor surface 106, through an arm holder 104. The C-arm 103 is mounted on an end portion of the arm holder 104 so as to be slidable in the direction indicated by an arrow a. The arm holder 104 is mounted on the upper portion of the stand 105 so as to be pivotal or rotatable in the direction indicated by an arrow b. The stand 105 comprises a stand fixed portion 105a fixed on the floor surface 106 and a stand movable portion 105b which can pivot about the column axis in the direction indicated by an arrow c.
The X-ray generating unit 101 and X-ray detecting unit 102 (to be collectively referred to as an imaging system hereinafter) are set at an optimal position in an optimal direction with respect to a subject (not shown) placed on a table top 107 by sliding the C-arm 103 in the direction a and pivoting the arm holder 104 in the direction b. In addition, the imaging system and the C-arm 103 can be retracted from the subject by pivoting the stand movable portion 105b in the direction c. Retracting the imaging system and the C-arm 103 makes it possible to ensure a working space around the head of the subject for a doctor or an examiner (to be referred to as an operator hereinafter) and facilitate replacement or repositioning of the subject on the table top 107 before or after examination, placement of anesthesia equipment, and the like.
Note that as the arm holder 104 described above, an L-shaped offset arm is generally used as shown in FIG. 8. Making the arm holder 104 have an L shape allows the C-arm 103 to be placed on a side of the table top 107. This makes it possible to move an end portion of the table top 107 in the longitudinal direction to near the stand 105 in the direction indicated by an arrow d. That is, using the L-shaped arm holder 104 makes it possible to enlarge the moving range of the table top 107 and expand the imaging range with respect to the subject. In addition, the L shape of the arm holder 104 have an advantage of being able to ensure a working space around the head of a subject for an operator.
However, the ensurance of a working space or the enlargement of the imaging range by pivoting the stand movable portion 105b or using the L-shaped arm holder 104 has its own limit because the stand 105 is fixed on the floor surface 106, and hence is not necessarily sufficient for the operator.
In order to solve such problems, a method has been proposed in which a ceiling-mounted C-arm holding apparatus having an arm whose one end is pivotally mounted on the ceiling and an arm holder mounted on the other end of the arm is used, and an imaging region of a subject can be arbitrarily set by aligning the position of the pivot axis of the arm with the central line of a table top in the longitudinal direction (see Jpn. Pat. Appln. KOKAI Publication No. 2000-70248).
According to the method disclosed in the above reference, since the arm holder is held on the ceiling through the arm, this holding apparatus has no stand fixed on the floor surface, unlike the conventional floor type C-arm holding apparatus shown in FIG. 8. Therefore, there is no obstacle to the movement of the table top, and the imaging system can be set at an optimal position with respect to any imaging target region of a subject.
However, the C-arm holding apparatus of a circulatory organ X-ray diagnostic apparatus is basically a floor type apparatus. It is therefore necessary for this floor type C-arm holding apparatus to ensure a sufficient work space and allow easy X-ray imaging at an arbitrary position without any limitation on the imaging range. In a dual plane system having an imaging system for cardiac angio, which is used for X-ray imaging with a relatively narrow field of view, and an imaging system for general angio, which is used for X-ray imaging with a wide field of view, e.g., imaging of the head or the lower limbs, two C-arm holding apparatuses, i.e., a floor type apparatus and a ceiling-traveling type apparatus, must be selectively used. When, in particular, the ceiling-traveling C-arm holding apparatus is to be used, it is desired that the floor type C-arm holding apparatus be retracted to an optimal area.

C-arm holding apparatus and X-ray diagnostic apparatus


Disclosed herein is a device that includes a plurality of first word lines each extending from an associated one of the first terminals in a second direction toward to the second terminals and terminating between the first and second terminals, the second direction being substantially perpendicular to the first direction, and a plurality of second word lines each extending from an associated one of the second terminals in a third direction toward to the first terminals and terminating near to an end of an associated one of the first word lines, the third direction being opposite to the second direction, each of the second word lines being substantially aligned with an associated one of the first word lines.

In the last years the memory market has been characterized by an increasing interest in high density devices and technology scaling has become more and more aggressive, both for memory core and circuitry, especially for the flash memory devices. While the technology is continuously improving to reduce the memory size, new solutions are studied to reduce the area of the related analog circuitry, which is not exclusively dependent on technology, but mainly on the specifically adopted layouts and architectures.
Redundancy and configuration information is extremely important for the correct working of a flash memory device. Both redundancy and configuration information are stored into the memory device during the test process of the flash memory device, prior to selling the device to an end user. Redundancy information does not need to be updated after it is stored at the end of the manufacturing process of the flash memory device, while configuration information needs to be updated into new data.
More in particular, redundancy information is used by the circuitry of the device to repair internal array defectiveness. For example, redundancy information is essentially composed by the addresses of the failed strings which are to be substituted by other strings that have been added to the matrix for this purpose.
Configuration information is used by the circuitry to define the value of important parameters used for the correct working of the circuitry itself. For example, configuration information relates to all circuit portions, both the analog portion and the digital portion, the current and voltage references, the power-on circuitry, all the regulators, the output values from the pumps, the clock frequencies of the oscillator, the inner algorithms, the output buffers and additional branches that can be connected or not to the configurations. Generally, during the design phase, it is usual to configure the circuits assuming it can happen that the silicon would function in a different way with respect to the behavior having been simulated by using reference models.
Next, a conventional way to store such information in flash memory devices is to use particular structures called "fuses". The information is written into the fuses by means of high currents that destroy the structure of the fuses themselves. A destroyed fuse conventionally corresponds to a logical "1", while a non-destroyed fuse conventionally corresponds to a logical "0". The fuse structures may store both the redundancy and configuration information.
However, in the convention way, the disadvantage in using fuses is that fuses are big structures and so a huge area is concerned. Moreover, the fuse needs to be destroyed when information is written therein, and the destroyed fuses cannot be repaired, therefore, once the information is stored in the fuse, it cannot be changed anymore.
Another conventional way to store redundancy and configuration information is to use memory cells in the array of the flash memory device. The cells share the sensing circuit with the other cells of the array. This way is more efficient in terms of area occupation than the above-mentioned convention way, and allows also changing the stored information by means of an erase operation.
However, in another conventional way, provided that the redundancy information is stored in the array of the flash memory device, until the array is accessed for read, such a redundancy information is thus not available. As a consequence, the reading of the redundancy information is obviously performed without knowing the redundancy information or adopting redundant technique. Therefore, such a read operation is difficult or could not be performed without an error. In this case, complex error correction algorithms have to be used, which made the read operation more complicated.
Another problem of this conventional way is that after the read operation the information has to be stored in an array of latches. This is because the redundancy and configuration information has to be ready for all the subsequent operations, and also because the sensing circuitry, that is shared with the memory array, should be kept free to read data from the memory array.
Still another problem of this conventional way, redundancy and configuration information has a different characteristic, that is, the redundancy information is not erased but only read, once after written in the flash memory, while the configuration information may be changed. Provided that the redundancy and configuration information are stored in a common erasing area such as block or sector of the flash memory device, the redundancy information is erased unnecessarily when the configuration information is erased.
With regard to reading correctly information such as redundant and configuration without an error, since the redundancy and configuration information need to be ready at the end of the power on phase of the flash memory device, the read operations for the redundancy and configuration information need to be performed before the end of the power-on phase. In this power-on phase of the device, if the voltage supply is not well controlled, the information is not correctly read out from the array. In general, since voltage supply to be used during the power-on phase in the device is ramping up, the read operation during this phase is difficult to be controlled well, therefore information is difficult to be read correctly without an error during this phase. Furthermore, the voltage ramp during the power-on phase depends on the device in which the flash memory device is used. For example, the device could be a USB portable storage device, a cellular phone, an electronic board, and the like. In each of such devices, the speed sloping, the presence or absence of glitches, the final value, the presence or not of intermediate plateau, and the like are different. This also makes the difficulty to control the voltage ramp well and to read information correctly without an error during the phase.

Memory device in particular extra array configured therein for configuration and redundancy information


A method, computer program product, and computer system for receiving, by a computing device, a plurality of file segments of a file, the plurality of file segments being received individually by the computing device. A first file segment of the file may be scanned to identify the presence of malware within the file segment. The first file segment of the file may be encrypted to create an encrypted file segment in response to identification by the scan of the first file segment that malware is absent from the first file segment. The encrypted file segment of the file may be sent to another computing device before a second file segment of the file is received by the computing device.

Typically, accessing a shared file over an environment such as a cloud computing environment may involve multiple steps. These steps often times involve the file being uploaded to the cloud computing environment service. Once uploaded, the file may be scanned to detect potential security issues. If no security flag is raised as a result of the scan, then a download of the file to the recipient computing device may be triggered.

System and method for improved accessing of a shared object


An engine is housed in an engine case and a propulsion unit driven by the engine is provided outside the engine case. By a swivel bracket installed in a predetermined part of the engine case, the propulsion unit is pivotally supported around a steering shaft, and centers of a drive shaft driving the propulsion unit and of the steering shaft are matched.

1. Field of the Invention
The present invention relates particularly to a steering device in an outboard motor.
2. Description of the Related Art
As a mainstream propulsion engine or a propulsion system of a craft or a boat, there are outboard motor, an inboard-outdrive motor, an inboard motor, and so on. The outboard motor among these is called an outboard drive or the like, and is integrally constituted with an engine, an auxiliary machine or the like thereof, a gear or a shaft of a driving system, a screw, and so on, and in general, is mounted on a transom board at a stern of a hull. The outboard system is typically mounted on a small-sized boat or the like, and has a steering function and a tilting function.
Further, the inboard-outdrive motor is called an inboard engine outboard drive or the like, as an installation method of a propulsion engine of a small-sized craft or the like, and an engine is mounted on an inboard stern portion and a drive unit made by integrating a reduction gear, a forward/backward clutch, a propeller, and so on is disposed in the exterior.
When such a boat actually travels on sea or on water, steerage is quite important, and various measures are taken in a steering device for steering. For example, a conventional outboard motor is fixed to a hull with a pair of clamp bracket portions, and a swivel bracket is supported between the clamp brackets via a through tube (tilt shaft). An outboard motor main body steers centering on a steering shaft on the swivel bracket. At a time of steering, a lift force (steering force) occurs in a lateral direction, and this force is transmitted to the hull via the clamp bracket.
Further, in a conventional small-sized outboard motor, a driving shaft and a steering shaft are matched. Therefore, a large steering angle can be set as a steering angle and is able to be steered, and in some cases steering of 360 degree is possible.
Further, in a conventional inboard-outdrive motor, a tilt shaft and a steering shaft are placed in a center of a universal joint of a drive shaft.
Further, a conventional method called sea drive is known and can achieve a large steering angle by mounting an outboard motor of large output on a swivel bracket in a manner to match a steering shaft and a drive shaft.
Further, a conventional form called POD is know, in which a drive shaft and a steering shaft match, and thus a large steering angle can be achieved, usually enabling a steering angle of about 360 degrees.
However, in the conventional outboard motor, the clamp brackets are fixed to the hull in a cantilever manner. Thus, at a time of trim movement (tilt), since a lift force (steering force) center comes away from the hull to the rear, the clamp brackets becomes open in a shape of separated "V". There has been a problem that an outboard motor cannot generate a large lift force (steering force) for the above reason. Further, there has been a problem that a trim (tilt) angle cannot be made large in a state of thrust. Further, there has been a problem that steering does not work well for a similar reason, leading to a poor performance of turning in a small radius.
Further, in the conventional small-sized outboard motor, an engine is mounted on a steering shaft receiving portion, and more concretely, a mount gum thereof is in an outer side of the steering shaft receiving portion. Thus, there has been a problem that engine vibration is easy to be transmitted to a hull. Further, since a span of a steering shaft receiver is short, the outboard motor can withstand a small propulsion force but cannot be applied to a large propulsion force as in a case of a large-sized outboard motor or the like.
Further, in the conventional inboard-outdrive motor, since a bending angle of the universal joint is limited, a tilt angle and a steering angle are smaller than those of an outboard motor. Therefore, there has been a problem that steering does not work well, leading to a poor performance on turning in a small radius.
Further, in the conventional method called sea drive, since an outboard motor engine part is positioned low in relation to a water surface, there is a problem that the engine is easy to be wetted, making it hard to keep reliability and corrosive resistance. Further, since the tilt shaft is positioned apart from a gravity center of the outboard motor, a large tilt device is necessary or an inertial mass is large, and thus there has been a problem that a large impact force occurs at a time of collision with a driftwood or the like.
Further, the above-noted conventional method is exclusive to a large-sized craft for which shallows are not taken into consideration, and there has been a problem that if the method is to be applied to a boat, the boat is largely damaged at a time of collision against an obstacle (including a seafloor) since there is no impact absorbing mechanism.
Further, in an outboard motor or the like of this kind, since a drive shaft and a steering shaft are matched, a large steering angle can be obtained, but because of the fact that a lift force (steering force) is supported by a gimbal surface (a mounting surface to a transom board) apart from the steering shaft, a large steering force cannot be given, resulting in a problem that high-speed turning in a small radius is not possible.
Further, since the steering shaft and the drive shaft match, the large steering angle can be given, but since the steering shaft (drive shaft) is not orthogonal to a traveling direction of a boat, a lateral direction component of the steering force is small and high-speed turning is not possible.
Further, since the engine is disposed at a high position and thus is advantageous in view of being wet, and in some cases mounting thereof on the hull is as simple as mounting of an outboard motor, but since the drive shaft is universally joined, there is a problem that neither a steering angle nor a tilting angle can be taken large.


Systems and methods for alerting to traffic proximity in the airport environment. Knowledge of the geographic position, speed, rate of change of speed, heading (or track-angle) and/or altitude of own-aircraft (or vehicle) and another, potentially conflicting aircraft (or vehicle) are used to calculate a predicted distance between the two aircraft (or vehicles) at given point of time in the future. If separation distance is predicted to be less than a predetermined acceptable value, then an alert message (aural, visual or both) is issued to the pilot or operator of the vehicle.

Several collision accidents have occurred at airports where an aircraft or vehicle has entered a runway environment which is already occupied by another aircraft that is moving at significant speed. Airborne collision protection and mitigation is provided by Traffic Collision and Avoidance System (TCAS), however the algorithms used in TCAS systems are not well suited to the airport surface operations problem; on airports, near runways, aircraft commonly operate at relatively high speeds in close proximity to other aircraft and vehicles. For example, an aircraft waiting to enter a runway is commonly stopped within a distance of the order of 100 feet from a runway that may be occupied by a landing aircraft traveling at speeds greater than 100 knots, thereby confusing TCAS algorithms. Also, on the ground at normal taxi speeds, an airplane can change its direction of travel much more rapidly than can an airborne aircraft.


A fuel supply device for an engine has a pump module comprising a fuel pump and a fuel filter. The pump module is housed within a sub-tank mounted in a fuel tank. The fuel filter is shaped arcuately in section and fitted around the outer circular periphery of the fuel pump. The sub-tank has a concave space on its outer periphery. The concave space and its above space accommodate therein a part of electrical connector, a fuel level gauge, electrical lead wires for the electrical connector and the fuel level gauge, a jet pump and a connecting pipe for the jet pump and a fuel return port. This arrangement reduces the diameter of the fuel supply device and facilitates mounting work of the fuel supply device in a limited space in the fuel tank.

1. Field of the Invention
The present invention relates to a fuel supply device which houses a fuel pump and a fuel filter in a sub-tank and is mounted within a fuel tank for an internal combustion engine.
2. Related Art
As a fuel supply device, JP-A 3-67058 proposes one type which houses a fuel pump within a sub-tank to maintain fuel in the sub-tank and enable the fuel pump to suck the fuel even when fluid in a main fuel tank decreases.
This type of fuel supply device is required to be as compact in size as possible to meet a recent trend to reduce in size any component parts mounted in a vehicle. Particularly when the main fuel tank is made of resin, the main fuel tank should have a sub-tank mounting hole as small as possible not to lower the rigidity and sealing performance of the fuel tank. Thus, the fuel supply device including the sub-tank and other component parts arranged outside of the sub-tank should be reduced in size as much as possible for facilitating mounting of the same through the sub-tank mounting hole, without reducing a volume of the sub-tank. Further, more component parts should be integrated into a module to facilitate assembling of the fuel supply device.

Fuel supply device housing pump and filter in sub-tank


3,5-Diaminobenzotrifluoride can be produced, in a single step, by reacting 4-chloro-3,5-dinitrobenzotrifluoride, in methanol, with hydrogen gas, in the presence of magnesium oxide, and in the presence of a catalyst comprising palladium on a carbon support.

This invention relates to a process for the preparation of 3,5-diaminobenzotrifluoride by the reduction of 4-chloro-3,5-dinitrobenzotrifluoride using hydrogen as a reducing agent in the presence of palladium on carbon as a catalyst. Since 4-chloro-3,5-diaminobenzotrifluoride is difficult to separate from 3,5-diaminobenzotrifluoride itself, it is a particular object of the present invention to provide a process which produces 3,5-diaminobenzotrifluoride without significant production of 4-chloro-3,5-diaminobenzotrifluoride.
The reduction of aromatic nitro compounds containing halogen on the aromatic ring is unpredictable. Hydrogenation using a palladium on carbon catalyst generally reduces the nitro group to an amine. However, the hydrogenation has been reported to fail in some cases. In addition, the effects of such hydrogenation upon a ring halogen are unpredictable. Occasionally the ring halogen is removed from the ring and replaced by a hydrogen. However, in many cases the hydrogenation leaves the ring halogen intact.
A. Weizmann discloses in J. Am. Chem. Soc., 71, 4154 (1949), that the catalytic hydrogenation of diethyl aminoethyl 4-nitro-2-chlorobenzoate using palladium on barium sulfate as a catalyst was impractical from a preparative point of view. The nitro compound was often incompletely reduced. The chlorine was occasionally removed from the ring while in other reactions it remained on the ring. Similar hydrogenation experiments conducted with 4-nitro-2-chlorobenzoic acid and its ethyl ester, using palladium on barium sulfate as a catalyst, produced variable results depending upon the solvent employed. In ethyl acetate, the reduction proceeded with retention of the chlorine. In this solvent, the acid and the ethyl ester gave quantitative yields of 4-amino-2-chlorobenzoic acid and ethyl 4-amino-2-chlorobenzoate, respectively. In isopropyl alcohol, the 4-nitro-2-chlorobenzoic acid and its ethyl ester were reduced to 4-aminobenzoic acid and its ethyl ester, respectively. In other words, in isopropyl alcohol the chlorine was removed in the reduction process. An aqueous solution of sodium 4-nitro-2-chlorobenzoate yielded, on workup, 4-aminobenzoic acid.
Bouchet et al. disclose in Syn. Commun., 4, 57-9 (1974), as cited in CA 81:25598m, that paranitrochlorobenzene may be reduced to parachloroaniline using hydrogen in the presence of a palladium on carbon catalyst in an aqueous alcohol solvent buffered to pH 7.
Ovchinnikov et al. (in Prikl. Hkim., (62), 37-44 (1969)) disclosed that meta and para chloronitrobenzenes may be hydrogenated to meta and parachloroanilines, respectively, using hydrogen gas and a 2% palladium on carbon catalyst. Approximately 2% dehalogenation was observed. It was also observed that the amount of dehalogenation was related to the type of carbon used as the catalyst carrier and depended upon the height of the catalyst bed.
U.S. Pat. No. 3,666,813 discloses that aromatic haloamines can be prepared by hydrogenating the corresponding chloro-nitro aromatic compound in the presence of a modified palladium on charcoal catalyst. The palladium on carbon catalyst is modified by treating it with a solution of a bismuth, lead, or silver salt.
U.S. Pat. No. 3,073,865 discloses a process for catalytically reducing halogen-substituted aromatic nitro compounds to the corresponding amines. The process is designed to reduce the aromatic nitro compound without removing the ring-halogens. The inventor discloses that magnesium oxide at levels between 0.1 and 1% by weight of nitro compound being reduced tends to prevent dehalogenation. At higher levels of magnesium oxide, magnesium oxide tends to promote dehalogenation. However, the examples provided in the patent show that in cases where the process did not produce the desired retention of the halogen atom, dehalogenation occurred to the extent of approximately 40%. In one case, a dechlorination of 80% occurred.
C. Paal and Christian Muller-Lobeck, Ber. 64b 2142-50 (1931), (as cited in CA 26 pp. 85 and 86) studied the hydrogenation of .alpha. and .beta.-chloro butyric acid, .alpha. and .beta.-chloro proprionic acid, and .alpha. and .beta.-chloro ethyl benzene. In each case, the .alpha.-chloro molecule more readily reacts with hydrogen to remove the chlorine than does the .beta.-chloro isomer. The catalyst employed for the reaction was palladium. The authors also observed that magnesium oxide promoted the reaction by reacting with the HCl released. In the absence of a base to absorb the HCl, the liberated acid prevents further hydrogenation.
European Patent Application EP 88667 (as abstracted in Chem. Abstracts 100:52475m and Derwent accession #C83-089930) discloses that chlorinated or brominated methylenedianilines can be prepared by the nitration and reduction of the corresponding aromatic halides. The reduction is carried out in methanol solvent with hydrogen gas in the presence of 5% palladium on carbon as a catalyst. The aromatic halide is retained during reduction.
Chakrabarti et al. disclose in two papers (J. Med. Chem. 23 pp. 878 and 884 (1980)) a multi-step reduction and cyclization reaction in which the first step is a hydrogenation using 10% palladium on carbon as a catalyst. The solvent was a mixture of ethanol and ethyl acetate. The molecules that are subjected to hydrogenation are substituted nitrobenzenes with a halogen at the 3 position and a substituted amino group at the 6 position. In one paper, the compound studied has fluorine as the halogen and in the other the halogen is chlorine. In each case, the nitro group was reduced to the amine while the halogen was not attacked.
Japanese Patent 63/010739 (as abstracted in Chem. Abstracts 109:92449y) discloses that chloro-fluoro-benzotrifluoride derivatives can be dechlorinated using hydrogen gas and 5% palladium charcoal catalysts in a methanol solvent. The ring chlorines are preferentially removed over the ring fluorines. Apparently no base was used in this process. Comparative Example 9 illustrates that a base is required to reduce the compound of the Applicant's process.
Vergnani et al. disclosed in Helv. Chim. Acta, 68, 1828, (1985), that 5-bromo-2-methyl-8-nitro-1,2,3,4-tetrahydroisoquinoline undergoes simultaneous removal of the aromatic bromine and reduction of the nitro group to an amine when treated with hydrogen gas in the presence of a 10% palladium on charcoal catalyst and triethylamine using methanol as a solvent.
Japanese Patent 58157749 (as abstracted in Chem. Abstracts 100:51247b) discloses that 2,2',4-trichloro-4',5-dinitrodiphenyl ether may be hydrogenated in the presence of 5% palladium on carbon catalyst in methanol to form 3,4'-diaminodiphenyl ether.
The substance that is reduced using the process of this invention, that is, 4-chloro-3,5-dinitrobenzotrifluoride, is a rather reactive molecule and can undergo side reactions during any reduction process. Crampton and Greenhalgh have disclosed in J. Chem. Soc., Perkins Transaction II, p. 187 (1986), that 4-chloro-3,5-dinitrobenzotrifluoride is subject to nucleophyllic attack on the chlorine. Thus, hydroxide ion can displace the chlorine to yield 4-hydroxy-3,5-dinitrobenzotrifluoride.
European Patent 038,465 discloses the reduction of 2-trifluoromethyl-4-chloronitrobenzene to 2-trifluoromethylaniline in a single step using hydrogen gas in a polar medium. The preferred solvent is water and/or a 1-3 carbon alcohol, especially methanol, and the preferred bases are alkali hydroxides, ammonia, or lower aliphatic amines. Attempts were made in our laboratory to reduce 4-chloro-3,5-dinitrobenzotrifluoride using the method set forth in European Patent 038,465. Comparative Example 1 and 2 illustrate that the procedure of this patent does not work in the case of 4-chloro-3,5-dinitrobenzotrifluoride. If the sodium hydroxide is added as part of the initial charge, the level of impurities is extremely high. On the other hand, if the nitro groups are reduced, and then the sodium hydroxide is added, the impurity level is only 6.3%. However, the amount of 4-chloro-3,5-diaminobenzotrifluoride found is approximately 40%.


A speed control method and device for a bicycle, aimed at synchronously controlling both front and rear derailleurs to achieve predetermined sequential combinations of front and rear gears of front and rear gear systems, respectively, for a gradual and smooth increase/decrease of speed of the bicycle.

The present invention relates in general to a method and a device for speed control of a bicycle. More particularly, the present invention relates to a method and a device for speed control of a bicycle which employ a synchronous control mechanism for bicycle front and rear derailleurs, which mechanism aimed at synchronously controlling both front and rear derailleurs to achieve predetermined sequential combinations of front and rear gears of front and rear gear systems of the bicycle, respectively, to enable a gradual and smooth increase/decrease of speed of the bicycle.
A Bicycle includes a front gear rotated via pedals by a bicyclist, the rotational movement of the front gear is transmitted via a chain to a rear gear, itself connected to the rear wheel of the bicycle. The number of rotations performed by the rear gear (and thus the rear wheel) per a single rotation of the front gear (i.e., pedals) equals the ratio, m/n, between the number of teeth (or radius) of the front gear, m, and the number of teeth (or radius) of the rear gear, n.
With reference now to FIG. 1. In order to enable more versatile and efficient riding, a speed controlled bicycle has been developed in which numerous discrete m/n ratios can be selected by the bicyclist. Thus, a speed controlled bicycle includes a front 20a and a rear 20b gear systems, at least one of the systems has at least two parallel gears each of a different radius (i.e., a different number of teeth). Typically the front gear system 20a includes two or three front gears 28a-c of different sizes and the rear gear system 20b includes five or six rear gears 22a-f of different sizes (i.e., 10, 12, 15 or 18 different gear combinations). A speed controlled bicycle further includes a front and a rear speed control devices, 24a and 24b, respectively, each includes a front derailleur 26a or a rear derailleur 26b, and derailleur operating means, 19a and 19b, respectively, to select a combination of a selected front gear and a selected rear gear to be engaged by the chain 18, to obtain a suitable and/or desired m/n ratio. Rear derailleur 26b typically includes means such as a tension pulley to maintain the chain at a predetermined range of tension (not shown).
For gear selection, each of the derailleur operating means 19a and 19b typically includes guiding means (known in the art as shifters) 21a and 21b, respectively. Each of guiding means 21a and 21b has segments 23a-c and 25a-f, respectively. Each of segments 23a-c and 25a-f has a predetermined gradually increasing or decreasing line-distance from the front 26a and rear 26b derailleurs, respectively. Thus, by separately guiding members 27a and 27b, to which members 27a and 27b connected are lines (wires, or as recently introduced to the art, hydraulic lines) 29a and 29b, themselves connected to front 26a and rear 26b derailleurs, respectively, along guiding means 21a and 21b, the locations of each of the front 26a and rear 26b derailleurs is separately and mechanically independently determined, to enable a separate selection of a specific front (28a in the example of FIG. 1) and a specific rear (22a in the example of FIG. 1) gears to be engaged by chain 18. It should be noted that prior art derailleurs operating means 24a and 24b are each mechanically independently operated by the bicyclist.
As for the simple bicycle described above, the front gear system of a speed controlled bicycle hereinabove described is forwardly rotated via pedals operated by a bicyclist, which forward rotation is transmitted onto the rear gear system by the chain, resulting in a forward rotation of the rear gear system and of the rear wheel therewith. Similarly to as described, the number of rotations performed by the rear wheel per a single rotation performed by the front gear system equals the ratio m/n, wherein m is the number of teeth (or radius) of a selected front gear engaged by the chain in the front gear system and n is the number of teeth (or radius) of a selected rear gear engaged by the chain in the rear gear system. Speed control is thus achieved by changing the m/n ratio, via mechanically independently selecting combinations of a gear of the front gear system via the front speed control device and a gear of the rear gear system via the rear speed control device.
The number of teeth in front and rear gears of a typical bicycle having three front gears (marked as `f`) in the front gear system and six rear gears (marked as `r`) in the rear gear system, and the m/n ratio for each of the eighteen combinations of front and rear gears, are given in Table 1 below.
TABLE 1 ______________________________________ # of teeth m r28 r24 r21 r18 r16 r14 ______________________________________ f28 1.00 1.17 1.33 1.56 1.75 2.00 f38 1.36 1.58 1.81 2.11 2.37 2.71 f48 1.71 2.00 2.29 2.77 3.00 3.42 ______________________________________
As shown in Table 1, the lowest speed is achieved selecting the smallest front gear, f28, and the largest rear gear, r28, wherein the m/n ratio equals 1.00. In this case, the number of rotations performed by the rear wheel per a single rotation performed by the front gear is 1.00. As further shown in Table 1, the highest speed is achieved selecting the largest front gear, f48, and the smallest rear gear, r14, wherein the m/n ratio equals 3.42. In this case, the number of rotations performed by the rear wheel per a single rotation performed by the front gear is 3.42.
Apparently a bicycle with the parameters described in Table 1, has eighteen (3.times.6) different speeds. For a gradual increase/decrease of speed, the bicyclist should select front and rear gear combinations with gradually increased/decreased m/n ratios, respectively.
Table 2 presents grades (1 through 18) for increasing m/n ratios as are calculated in Table 1, wherein 1 represents the lowest ratio (i.e., 1.00 in the given example) and 18 represents the highest ratio (i.e., 3.42 in the given example).
TABLE 2 ______________________________________ # of teeth m r28 r24 r21 r18 r16 r14 ______________________________________ f28 1 2 3 5 8 11 f38 4 6 9 12 14 15 f48 7 10 13 16 17 18 ______________________________________
Table 3 presents the combined number of teeth (n+m) for each of the eighteen combinations, which combined number being an indication of the tension imposed on the tension pulley, wherein the higher the combined number is, the higher the tension is and vice versa.
TABLE 3 ______________________________________ # of teeth m r28 r24 r21 r18 r16 r14 ______________________________________ f28 56 52 49 46 44 42 f38 66 62 59 56 54 52 f48 76 72 69 66 64 62 ______________________________________
From this description it is apparent that following the eighteen sequentially increasing/decreasing m/n ratios have few drawbacks as follows.
First, as best seen in Tables 1 and 2, gradually increasing/decreasing the m/n ratios involves a non linear, neither smooth increase/decrease of the ratio, wherein few (i.e., two or more) sequential combinations (e.g., from f28/r18 to f38/r24; from f28/r16 to f38/r21) have similar m/n values, some even have identical values (e.g., from f48/r24 to f28/r14), whereas other sequential combinations are characterized by big differences in their m/n ratios (e.g., from f38/r28 to f28/r18; from f38/r16 to f38/r14), resulting in a non smooth operation.
Second, as best seen in table 2, following the 1 through 18 combinations involves, in many instances, shifting a gear in both front and rear gear systems and furthermore, involves gear shifting between non-adjacent gears in the same gear system (i.e., front and/or rear). For example, shifting from combination 10 to combination 11 involves shifting from the smallest rear gear, r14, to the largest, r28, in the rear gear system and from the smallest gear, f28, to the largest gear, f48, in the front gear system. Therefore, this type of operation is impractical for both the average and professional bicyclist.
Third, as best seen in Table 3, following combinations 1 through 18 involves high changes of tension imposed on a spring being part of the tension pulley of the rear derailleur. For example while moving from combination f28/r18 to combination f38/r24, the combined number of teeth changes from 46 to 62.
And finally, since the largest front gear and the largest rear gear are positioned opposite in relation to the frame of the bicycle, typically the largest front gear is away from the frame and the largest rear gear is close to the frame, few combinations characterized by a highly diagonalized position of the chain are not recommended due to the high friction thus formed between the gears and the chain. In the given example these combinations are f48/r28, f38/r28, f28/r14 and f38/r14, underlined in Table 2.
Reviewing the data presented in Table 1 above reveals that by selecting only 10 combinations, A through J, presented in Table 4 below, overcomes all of the above listed limitations.
TABLE 4 ______________________________________ # of teeth m r28 r24 r21 r18 r16 r14 ______________________________________ f28 A B C f38 D E f48 F G H I J ______________________________________
Thus, following the A through J combinations have advantages: (1) it provides a gradual and smooth increase in the m/n ratio; (2) only twice the bicyclist is required to shift gears both at the front and rear gear systems, that is while moving from combination C to combination D and from combination E to combination F; (3) in all gear shifts only adjacent gears are involved; (4) the combined number of teeth ranges from 49 (combination C) to 62 (combination J) thus limiting the tension range imposed on the spring of the tension pulley of the rear derailleur, thereby prolonging its life span, and (5) it avoids chain diagonalization.
However, following the A through J combinations requires (1) calculating this root as was done hereinabove in Tables 1 through 4 (2) memorizing thus calculated root; (3) employing both a front and a rear speed control devices to be in some cases operated mechanically independently, yet as simultaneously as possible, by the bicyclist.
There is thus a widely recognized need for, and it would be highly advantageous to have, a method and a device providing a synchronous control mechanism for bicycle front and rear derailleurs, which mechanism is for synchronously controlling both the front and the rear derailleurs, to achieve predetermined sequential combinations of front and rear gears for obtaining a gradual and smooth increase/decrease of speed of a speed controlled bicycle.

Method and device for speed control of a bicycle


A data storage system that includes first and second controllers is provided. Data is mirrored from one controller to the other controller according to different steps depending on the amount of data to be mirrored. When the data to be mirrored is less than or equal to a predetermined number of bytes, one less interrupt is generated than when the data to be mirrored is greater than the predetermined number of bits.

A typical data processing system generally includes one or more storage units or devices which are connected to a host computer either directly or through a control unit and a channel. The function of the storage units is to store user data and other information (e.g., program code) which the host computer uses in performing particular data processing tasks.
Various types of storage units are used in current data processing systems. A typical system may include one or more large capacity tape units and/or disk drives connected to the system through respective control units for storing data. However, a problem exists if one of the storage units fails such that information contained in that unit is no longer available to the system. Generally, such a failure will shut down the entire computer system, which can create a problem for systems which require data storage systems to have high availability.
This problem has been overcome to a large extent by the use of Redundant Array of Inexpensive Disks (RAID) systems. RAID systems are widely known, and several different levels of RAID architectures exist, including RAID 1 through RAID 5, which are also widely known. A key feature of a RAID system is redundancy, which is achieved through the storage of a data file over several disk drives and parity information stored on one or more drives. If one disk drive fails, then the RAID system is able to reconstruct the data which was stored on the failed drive from the remaining drives in the array.
High availability is a key concern because in many applications users rely heavily on the user data stored on the RAID system. In these type of applications, unavailability of data stored on the RAID system can result in significant loss of revenue and/or customer satisfaction. Employing a RAID system in such an application enhances availability of the stored user data, since if a single disk drive fails, user data may still be stored and retrieved from the system. In addition to the use of a RAID system, it is common to use redundant RAID controllers to further enhance the availability of such a storage system. In such a situation, two or more controllers are used in a RAID system, where if one of the controllers fails the other remaining controller will assume operations for the failed controller. Such a platform enhances the availability of a RAID system because the system can sustain a failure of a controller and continue to operate. When using multiple controllers, each controller may conduct independent read and write operations simultaneously, known as active-active configuration. It can be advantageous in many applications to use the active-active configuration, as such a RAID system can support higher rates of data transfer between the disks and host. However, employing an active-active configuration requires mirroring of user data and parity between controllers to maintain redundancy, such that if one controller fails, the remaining controller can continue operations of the system without any user data loss.
With reference to FIG. 1, a RAID system 10 having an active-active controller pair is described. The RAID system 10 is connected to a host computer 14 through a host channel 18. The RAID system 10 includes a first active controller 22, a second active controller 26, and a disk array 30. The disk array 30 is connected to the first active controller 22 and the second active controller 26 by a disk channel 34. The disk array 30 contains a number of disk drives 42, 46, 50, 54, 58, that are used for data storage. Within the first active controller 22, there is a processor 62 and a nonvolatile random access memory (NVRAM) 66 which has a first region 70 and a second region 74. Within the second active controller 26 there is a processor 78 and a NVRAM 82 which has a first region 86 and a second region 90. It should be understood that the number of drives shown in FIG. 1 are for the purpose of discussion only, and that a RAID system 10 may contain more or fewer disk drives than shown in FIG. 1. User data is written to the disk array 30 in such a way that if one drive fails, user data can continue to be read from and written to the disk array 30. How this redundancy is accomplished depends upon the level of RAID architecture used, and is well known in the art.
When storing user data, generally, a controller receives the user data and breaks the user data down into chunks which will be stored on the individual disk drives 42, 46, 50, 54, 58. A chunk of data is the portion of the user data that can be stored on an individual disk drive. The chunks of data are then arranged to be stored on the drives 42, 46, 50, 54, 58. In arranging the chunks of data, the controller organizes the chunks into stripes and generates parity for each stripe. The chunks of data are written across several drives, and the parity for that stripe is written to one disk drive.
As mentioned above, when using an active-active controller pair in a RAID system, in order to maintain redundancy, data and parity must be mirrored between the controllers in the active-active system. In such a system, when the host computer 14 sends user data to be written to the disk array 30, the user data is typically sent to either the first active controller 22, or the second active controller 26. Which controller the user data is sent to depends upon a number of factors, including the LUN the user data will be written to. A LUN is a SCSI term referring to a unit containing addressable storage, with each controller typically being assigned to or owning one or more of a number of LUNs. Thus, if the user data is to be written to a LUN that the first active controller 22 owns, the user data is sent to the first active controller 22. Likewise, if the user data is to be written to a LUN that the second active controller 26 owns, the user data is sent to the second active controller 26. In order to maintain redundancy between the two controllers 22, 26, the user data sent to the first active controller 22 must be copied onto the second active controller 26. Likewise, any user data sent to the second active controller 26 is copied onto the first active controller 22. The user data is copied between controllers because, for example, if the first active controller 22 suffers a failure, the second active controller 26 can then use the copy of the user data to complete any data writes which were outstanding on the first active controller 22 when it failed. This process of copying user data, as well as parity, between active controllers is known as mirroring.
Mirroring in such a system is typically necessary because when the host 14 sends user data to be written, the controller that receives the user data, stores the user data in a memory location, and sends a reply to the host 14 that the write is complete. Thus, even though the user data may not have been written to the disk array 30, the host 14 is notified that it has been written. If the controller that received the user data subsequently suffers a failure prior to writing the user data to the disk array 30, the data can be lost. However, if the controller mirrors the user data prior to sending the host 14 a reply that the data has been written, a failure of the controller can still be recovered without loss of the data, using the copy of the user data that was mirrored to the other controller.
In many RAID applications, the controller(s) communicate with the host computer and disks using a Small Computer System Interface (SCSI) bus architecture. SCSI systems are widely available, with a variety of SCSI controllers available. Different components within a SCSI system communicate using either SCSI commands, or SCSI data transfers. SCSI commands are generally 10 byte or 12 byte command blocks, with command blocks of up to 16 bytes (128 bits) available in certain applications. Many SCSI controllers can process SCSI commands of up to 12 bytes without having to treat the command in a special manner. In these types of systems, SCSI commands of greater than 12 bytes are treated differently, often requiring processor attention for each individual byte of command beyond 12 bytes.
SCSI data transfers are used to transfer data between components in a SCSI system. A SCSI data transfer is generally required when a block of data needs to be transferred. When initiating a SCSI data transfer, the SCSI controller receiving the data transfer must be notified that the data is coming, in order to prepare to receive the data. Thus, a data transfer in a SCSI system in generally at least a two step process, a SCSI command is first sent to the receiving SCSI controller, followed by one or more SCSI data transfers.
When mirroring data between controllers 22, 26, several operations are performed by each controller 22, 26. With reference now to FIG. 2, a flow chart representation of a data mirroring operation is described. Initially, indicated by block 200, the host computer 14 sends user data to the first active controller 22, which opens a write operation. Next, as noted by block 204, the first active controller 22 sends a notification mirror message, which causes an interrupt, to the second active controller 26, notifying the second active controller 26 that data is going to be mirrored. An interrupt is a signal sent from a device, in this example the first active controller 22, to a processor, in this example the processor 78 portion of the second active controller 26, which causes the processor 78 to stop what it is doing and service the interrupt. When the second active controller 26 receives the interrupt, it discontinues any processing activity, and processes the notification mirror message. The notification mirror message is a SCSI command, and will be described in more detail below. Next, as indicated by block 208, the first active controller 22 sends a metadata mirror message including metadata, which causes an interrupt, to the second active controller 26. The metadata mirror message is a data transfer between controllers, will be described in more detail below. The second active controller 26 then marks its NVRAM 82 as invalid for the data blocks specified in the metadata, as noted by block 212. Next at block 216, the first active controller 22 sends a data mirror message containing the user data, which causes an interrupt, to the second active controller 26. The data mirror message is a data transfer between controllers, which contains the actual user data. The second active controller 26 receives the user data, stores it in the appropriate NVRAM 82 location, marks the NVRAM 82 as valid for the associated data blocks, as indicated by block 220. At block 224, the second active controller 26 sends a status message to the first active controller 22, indicating that the data was received and stored. The first active controller 22 upon receiving the status message sends the host computer 14 an indication that the write is complete, and terminates the write operation as noted by block 228. The first active controller 22, at block 223, then writes the user data to the disk array 30. As can be seen from this example, the controller receiving the mirrored data receives at least four interrupts. At least two interrupts associated with data transfers between controllers, and two interrupts associated with SCSI commands which indicate mirroring operation are starting or are complete. As will be understood by those of skill in the art, a processor may disconnect during a data transfer. In such a situation, the sending controller will, after a predetermined time, resume sending the data, causing an additional interrupt. Thus, the minimum number of interrupts associated with a data transfer as described will be four interrupts, with additional interrupts possible if there are disconnects between the controllers when data is being transferred.
As described above with reference to block 208, the first active controller 22 sends a notification mirror message, which causes an interrupt, to the second active controller 26. The notification mirror message serves to simply place the second active controller 26 on notice that metadata is going to be mirrored. A separate notification mirror message is required because, as described above, prior to the metadata mirror message, the second active controller 26 needs to be aware a data transfer is coming. The notification mirror message is typically a 10 byte SCSI command, with the first byte containing a predefined hexadecimal number, for example 3C. When the second active controller 26 receives the notification mirror message and interrupt, it discontinues any operations that it was conducting to service the interrupt. The second active controller 26 then processes the notification mirror message and reads the hexadecimal number in the first byte. When the second active controller 26 reads the predefined hexadecimal number, 3C in this example, it recognizes this as a mirror notification command, and disregards the remaining 9 bytes of the notification mirror message. The second active controller 26 then prepares to receive the data transfer of the metadata mirror message from the first active controller 22.
With reference now to FIG. 3, a metadata mirror message 300 is now described. The metadata mirror message 300 is a SCSI data transfer, which contains a first data region 304 and a second data region 308. The first data region 304 in this example is a 512 byte structure which contains several information fields. The information fields of the first data region 304 include a 16-bit message type 312 field, which contains information which indicates that the message contains metadata. The next field is a 16-bit message length 316 field, which contains information on the length of the current message. Following the message length 316 field, is a 32-bit sequence information 320 field, which in one example contains a number which is incremented during each mirror message, and is primarily used for troubleshooting purposes. The next field is a 32-bit starting logical block address (LBA) 324 field, which contains the starting LBA in the disk array 30 where the user data will be written. Following the starting LBA 324 field is a 32-bit number of blocks 328 field, which contains information on the number of blocks of user data to be mirrored. The next field is an 8-byte array serial number 332 field. In many applications, the disk array 30 contains several arrays of disk drives, with each array of disk drives having a unique array serial number. The array serial number field 332 contains the serial number of the array to which the user data is to be written. Following the array serial number field 332 is an 8-bit memory region field 336, which contains information on the region of NVRAM 66 that the data is to be stored in, the first region 86 or the second region 90. Following the memory region 336 field is an 8-bit array number 340 field. In many applications, each array of disk drives within the disk array 30 may contain several RAID arrays. Each RAID array is given an array number, such that if a controller 22, 26 knows the array serial number and array number, it can read and write data to and from the appropriate RAID array. Following the array number field 340, is a portion 344, which may contain data, used to fill out the 512 byte transfer.
The second data region 308 contains a 512 byte scatter/gather list 348. The scatter/gather list 348 is a list of scatter/gather elements 352. In the example of FIG. 3, the scatter/gather list 348 contains 64 scatter/gather elements 352. Each scatter/gather element 352 contains a 32-bit starting address field 356 and a 32-bit byte count field 360. The starting address field 356 contains the 32-bit address within the NVRAM 82 where the associated data will be stored. The byte count field 360 contains information on the number of bytes contained in the associated data. Thus, using the starting address field 356 and the byte count field 360, the portion of NVRAM 82 where the associated data will be stored is uniquely defined. Each scatter/gather element 352 is able to define the storage area for 16 Kbytes of user data. Thus, in the example shown, the metadata mirror message 300 can provide metadata for up to 1 Mbyte of user data. If more than 1 Mbyte of user data is sent to the controller 26 for storage, the controller 26 breaks the user data into separate pieces which are 1 Mbyte or less. The controller 26 uses the information contained in each scatter/gather element 352 to mark the appropriate portions of NVRAM 82 as invalid.
As mentioned above, the processor on the receiving controller is interrupted at least four times for each data write that is mirrored to it. Servicing these interrupts can take a significant portion of the processing resources of a controller. Additionally the metadata mirror message is 1 Kbyte, regardless of the size of the data write. Thus, for example, if 512 bytes of user data are received at the first active controller 22, the metadata mirror message will be 1 Kbyte. As can be seen, for small writes, mirroring a 1 Kbyte metadata message can be inefficient. Furthermore, when mirroring data, the controllers 22, 26 send the data over the disk channel 34, which typically have a maximum bandwidth of 160 Mb/s. When a RAID system is receiving many read and write requests from the host 14, the disk channel 34 can become bandwidth limited, increasing the time required to complete a read or write operation.
The occurrence of small writes is common in many applications, such as financial, reservation and retail systems, where relatively small data records are widely used and are accessed and modified at random. These applications are often very active as well, with many read and write requests sent to the RAID system within relatively short time periods. In these types of applications, it would be especially advantageous to reduce the processor overhead required for servicing interrupts, and to reduce the disk channel bandwidth used for mirroring data.
Thus, it would be advantageous to have a method and apparatus which (1) reduces the number of interrupts the processor of a receiving controller receives during mirroring operations, and (2) consumes less channel bandwidth when mirroring data between controllers of an active-active controller pair.

Data mirroring between controllers in an active-active controller pair


An intake structure for a motorcycle provides an intake air flow passage in a fuel tank arranged at an upper portion of a vehicle body. Left and right upper tank members are provided at an upper portion of a vehicle body. The upper tank portions are each provided with a recessed portion that is opened upward and inward. A tank wall, having an L-shaped cross section, extends rearward and subsequently downward. An upper opening of the recessed portion is covered with a lid member, and thereby, the recessed portion effectively functions as an air-supply passage leading to an interior portion of an air cleaners.

1. Technical Field of the Invention
The present invention relates to a fuel tank incorporating an intake structure for a motorcycle, and to a motorcycle incorporating such a fuel tank.
2. Background Art
A structure for a motorcycle is known, in which a hollow portion is formed in a main frame, the hollow portion configured as an intake passage extending rearwardly from a head pipe (for example, see JP Patent No. 4291044.
If a lightweight intake passage is arranged on a high place, such arrangement is advantageous in terms of lowering the center of gravity of a vehicle body.
In the conventional structure described above, such structure is advantageous for lowering the center of gravity, however, a shape of the main frame becomes complicated. Also, the degree of freedom in layout of the intake device is reduced.

Fuel tank for motorcycle, and motorcycle including same


A safety switch device for monitoring the position of a protective cover, the cover being pivotable about an axis into and out of a closed position. The safety switch device includes a fixed position switch unit which houses at least a first electrical signal generator which will be switched between states in response to movement of the protective cover from the closed position, the signal generator being operated by an actuator which rotates about an axis. The switch device also includes a fastener element which is adjustably mountable to the protective cover and an articulated mechanical coupling which extends between the fastener element and the signal generator actuator, the coupling element being movable in at least two planes.

(1) Field of the Invention
The present invention relates to enhancements in security devices and, particularly, to the generation of signals commensurate with the state of a mechanical closure member through which access to a secured device or area is obtained. More specifically, this invention is directed to an improved safety switch unit and, especially, to a signal generator for monitoring the position of a protective cover and providing command and/or control signals commensurate with whether that cover is in an open or closed condition. Accordingly, the general objects of the present invention are to provide novel and improved methods and apparatus of such character.
(2) Description of the Prior Art
Devices for monitoring the position of protective covers, and producing command signals which energize a warning device and/or activate a disabling device, are well-known in the art. By way of example, German Patent 1,553,550 discloses a stop device for a damper which opens via a heat-sensitive cut-out. In this prior art device, a holder for a stop bolt is affixed to the inside of the damper, the stop bolt being movably mounted in the holder and being normally blocked by a stop member. When the cut-out is released, the stop member enables the stop bolt to move either under the influence of gravity or in response to a spring bias. However, in this rather primitive early device, there is no provision for monitoring the open and closed positions of the damper.
Another example of the prior art is disclosed in published German Patent Application 40 13 994. This published application is directed to a safety switch, which is associated with a door or the like, the door rotating about a shaft. The safety switch is provided with a disk-shaped actuating cam. This actuating cam also rotates about the shaft, in response to movement of the door, and simultaneously actuates, via tappets, a pair of switches. In the safety switch of the published application, the actuating cam is seated on the shaft about which the door rotates and, accordingly, both assembly of the device and subsequent adjustment for proper operation are difficult. Indeed, such difficulties seriously limit the ability to retrofit existing protective covers with such a prior art safety switch device.