An acetabular instrument has a handle portion having one or more solid nonflexible drive shaft elements therethrough. The shaft elements are connected by a U-joint at one of both ends to form a flexible curved drive shaft. One end of a solid shaft element is connected to a knob so that rotation of the knob drives the flexible shaft. The flexible shaft is housed within a hollow curved body preferably made of stainless steel. One end of the curved body it is connected to the handle portion and at the other end to an acetabular cup or acetabular reamer holder. The reamer holder is rotatably driven by the flexible drive shaft. The knob may be made so that it may receive blows from a mallet allowing the instrument to be used as an impactor. The drive shaft may be used to actuate a locking mechanism within the cup or reamer holder which connects the reamer cup to the instrument.

Over time the surgical technique for total hip replacements has evolved. Incision length has been reduced over time as surgeons become more comfortable operating with limited visibility. The location of the incision has also been changing as surgeons have developed and implemented different approaches to the joint. These two factors have increased the challenges of implanting acetabular implants in the correct orientation as the acetabular tools impinge on bone or soft tissue around the perimeter of the incision.
Acetabular implants normally consist of a shell or cup and a modular insert that fits within the shell and acts as a bearing surface for the femoral head. While modular shells and inserts are preferred for a number of reasons, there is an application where shells and inserts are combined preoperatively in a monoblock construction. Such shells and inserts are shown in U.S. Pat. No. 6,475,243, the disclosure of which is incorporated herein by reference.
Acetabular instruments normally consist of a series of reamers, a reamer handle, a shell positioner/impactor and an insert positioner/impactor. In addition, alignment guides are often attached to the reamer handle and shell positioner/impactor in order to facilitate alignment. A typical reamer is shown in U.S. Pat. Nos. 4,023,572 and 5,658,290.
Shells are implanted into an acetabulum after the acetabulum has been prepared to receive the shell through the use of a series of reamers increasing in size. The shells are aligned in the acetabulum according to two angles: abduction and anteversion. The combination of these two angles creates the axis that the shell should be aligned and impacted on.
Traditionally acetabular reamer handles and shell and insert positioner/impactors had straight shafts. In some surgeries the size or location of the incision results in the shaft of these instruments impinging on the side of the incision before the preferred abduction/anteversion axis is achieved. In these cases the surgeon has to force the soft tissue or bone out of the way, increase the length of the incision, or accept the abduction/anteversion angle that can be achieved. None of these options are preferred.
One method for avoiding impingement between these acetabular instruments and the incision is to create inline or offset curved acetabular instruments. "Inline" refers to an acetabular instrument that has a curved section between the two ends of the instrument that lie on the same axis. Typically, the first end includes a hex drive for connection to a rotary power service (drill) and a second end which has a holder for an acetabular instrument such as a reamer or the acetabular shell itself. "Offset" refers to an acetabular instrument that has a curved section between the two ends of the instrument that lie on different axis. The curved section should begin as quickly as possible after the attachment to the reamer, shell or insert in order to minimize the impingement.
An inline curved or offset acetabular instrument is preferred for a number of reasons. Typically, the surgeon is used to operating with inline straight instruments. By maintaining the inline aspect of the design, the ergonomics of the instrument remain the same and the surgeon learning curved is reduced. In addition an inline instrument allows for all forces to be projected in line or parallel to the correct axis. Finally, an inline instrument allows for alignment guides to be indexed around the axis of the instrument without changing its position in relation to the implant. In-line or offset reamers/impactors are shown in U.S. patent publications 2003/0050645, 2003/0229356, 2004/0153063, 2004/0087958, 2005/0038443 and 2005/0216022.
The introduction of a curve into acetabular instrument introduces various challenges to designing a reamer handle. Reamer handles are used to transmit torque and axial load from a power source, such as a rotary power source to the reamer. This is accomplished through the use of a straight shaft with a fitting that mates with the power source on one end and a locking mechanism that connects to the reamer on the other end. The torque is transmitted from the power source to the fitting to the shaft to the locking mechanism and finally to the reamer. The axial force is transmitted from the surgeon to the power source to the shaft to the locking mechanism to the reamer.
The same holds true for the shell positioner/impactors. Shells are typically connected to positioner/impactors by threading the two together with torque. This is accomplished through the use of a straight shaft with a handle that the surgeon grips on one end and a threaded fitting that connects to the shell on the other end. The torque is transmitted from the surgeon to the handle to the shaft to the threaded fitting to the shell. The axial force is transmitted from the surgeon to the mallet to the handle to the shaft to the threaded fitting to the shell.
With an inline or offset curved acetabular instrument the torque and axial load needs to be transmitted around a curve. In addition, the curved body that transmits the axial load cannot also transmit the torque. This is because the curved body would impinge on the incision if one tried to rotate it through a full rotation. To solve this problem, a handle having a hollow curved body with a drive train housed internally is provided. The drive train needs to be able to transmit torque through the curved body. This is accomplished through the use of U-joints and/or flexible shafts.
In the case of an offset curved instrument, two u-joints allow the transmission of torque between the two ends of the instrument. In the case of an inline curved instrument a series of U-joints (5-6) or a combination of U-joints (2) and a flexible shaft allows the transmission of torque between the two ends of the instrument. There are many other combinations and permutations of U-joints and flexible shafts that would meet the requirements.
The curved body is preferably machined from a solid block referred to as a monoblock, to produce the curved body rather than using a bent tube. The use of a machined body allows for increased precision of the instrument and drive train. The internal drive-train can easily be removed without the use of tools once a moveable lid is opened. This is because the multiple U-joint drive shaft is flexible and is held at position at the ends within fixed U-joints mounted to the curved body only by mating hex couplings. These couplings may be easily slid apart to disassemble the drive-train from the handle. The monoblock also serves to mount modular navigation and alignment guides such as a typical mechanical guide or a well-known optical navigation tractor. Obviously if no guide is necessary, the mounting position on the monoblock curved body can be left empty.
The modular alignment system can be attached to the body of the instrument preferably adjacent the handle. This alignment system is indexible. This allows the mechanical or optical tracker system to be positioned properly with respect to the typical acetabular cup or shell which has a plurality of screw holes therethrough. The indexible alignment system also allows for left and right positions for the impactor/reamer and allows proper positioning of the curve and minimization of impingement with adjacent soft tissue.
In one possible embodiment a modular cup or reamer holder includes an actuatable release mechanism which can be connected the curved impactor/reamer by a push button mechanism described below. The cup or reamer holder can then be attached and/or disconnected such as by threading a threaded projection on the leading end of the modular holder into a threaded bore in the cup. This can be accomplished by turning a knob at the end of the handle which turns the drive-train which in turn rotates the threaded tip. Disconnection is accomplished by turning the knob at the end of the handle in the opposite direction. The design can be reversed with the actuatable release mechanism being located on the end of the handle. This simplifies the design of the modular cup or reamer holder and reduces cost since only one release mechanism is necessary when multiple holders are used.
If a modular holder is utilized, the cup initially could be threaded onto the holder or tip while disconnected from the curved positioner or impactor. The holder cup combination can then be inserted into the hip joint, perhaps sideways as for a smaller incision, and then reconnected to the curved positioner. The modular holder can be removed from the cup and incision if the curved impactor fails during impaction. The user can disconnect the modular cup holder and utilize a new impactor by reconnecting the impactor end to the modular cup holder or tip.
This modularity also allows a user to have multiple holders designed both for preassembled metal shells and polyethylene or ceramic bearings. Thus one holder can be designed to engage the polyethylene bearing of a preassembled acetabular cup and a second modular holder designed to engage a cup design having an outer shell and a ceramic bearing. Obviously, one-piece prosthetic cups made of polyethylene or ceramic could also be gripped. These modular holders can be supplied as part of a kit which has one positioner/impactor and several holders designed to couple to different implants rather than having multiple positioner/impactors.
The preferred embodiment of the shell positioner/impactor of the present invention uses a series of U-joints. Two U-joints are fixed in the corners (one at each end) of the curved body and a chain composing of preferably four U-joints is assembled between the two end U-joints. The preferred U-joint chain is assembled by connecting two male hex fittings to female counterparts of the two corner U-joints. The U-joint chain is preferred because it transfers torque rigidly and is easy to clean.
An alternate embodiment uses a wound wire flexible shaft between the two corner U-joints. The wire flexible shaft is assembled to the two corner U-joints with the hex fittings. While the wire flexible shaft has a lower cost, it is less preferred due to spring-like torque transfer (i.e. the shaft twists before torque is transmitted) and typical flexible shafts have cleanability problems.
While the drive train can be mounted externally on the curved body or internally in the curved body, it is preferred to mount the drive train internally for a number of reasons. The drive train rotates at high speeds in the reamer handle and there would be a risk to the surgeon if it were mounted externally. Additionally, it is possible for the drive train to catch on soft tissue if it is mounted externally. Also, external mounting increases the amount of instrument components in the surgeon's field of view, and consequently decreases the surgeon's view of the incision.
The drive train can be mounted permanently or it can be removable. The preferred embodiment is to have a removable drive train mounted internally. This allows for the drive train to be replaced as it wears out or becomes obsolete without replacing the entire instrument. In addition it allows the drive train to be removed for cleaning.
The drive train is captured inside the curved body through the use of the curved lid. The curved lid can be assembled and disassembled from the curved body so that the drive train can be removed for cleaning or replacement. The monoblock curved body and lid construction is preferred over a curved tube design. A solid curved tube with an internal drive train without a lid for access cannot easily be cleaned while a tube with a curved lid can be easily disassembled from the curved body so that the internal components like the U-joints and drive train can be easily cleaned. The curved lid adds strength to the curved body. The curved body and curved lid assembly can handle more axial load than an open curved body alone.
Modular holder/tips have been developed that mate with shell implants, polyethylene inserts and ceramic inserts. In the preferred embodiment, the modular tips all connect to the shell positioner/impactor in the same fashion. A spring-loaded button in the modular tip or holder deflects an internal ring to an aligned position and released after assembly to and then engages a groove on the shell positioner/impactor providing an axial capture. There are many different methods for achieving this type of connection between the modular holder and the shell positioner/impactor. A socket feature, such as in the modular tip engages a mating feature on the shell positioner/impactor providing a radial anti-rotation constraint. This allows torque to be transmitted between the curved body of the shell positioner/impactor and the modular tip body. In the preferred embody a hexagon or octagon is formed within the modular tip end. Obvious any shape which prevents radial and rotational movement can be used. Additionally in a preferred embodiment, an internal hex fitting in the modular tip engages a mating socket in the shell positioner/impactor. This allows for torque to be transmitted between the drive-train of the shell positioner/impactor to the hex fitting on the modular tip holder. Obviously the inverse of this design could also be used with the socket on the modular tip or holder.
In the preferred embodiment applying contrasting torque forces through the knob and handle of the shell positioner/impactor actuates and deactuates each modular holder/tip. A clockwise rotation of the knob results in a lock and counterclockwise rotation of the knob is used to unlock. The surgeon transmits torque internally through the instrument by turning the knob which then transmits torque to the drive-train to the hex fitting to the locking mechanism while external torque is transmitted from the surgeon to the handle to the curved body to the tip socket. These two contrasting forces allow for the actuation of the locking mechanisms from a distance. To transmit axial force the surgeon impacts the knob with a mallet which transfers force to the handle and the curved body then to the tip and finally to the implant.
In some incisions it would be preferred to introduce the shell and bearing insert without an instrument attached in order to reduce the overall cross-section of the assembly. This is challenging with a straight impactor for instance, because it is difficult to thread the straight impactor and shell together within the incision. Furthermore a straight impactor impinges on tissue making it even more difficult to align. The modular holder tip facilitates the coupling of the impactor/positioner with a cup by allowing the user to lock the holder/tip onto the implant prior to insertion, disconnect it from a shell positioner/impactor, insert the implant holder/tip assembly into the incision and reconnecting in vivo. This is because of the larger bore in the holder and the use of a quick connect feature. This method is particularly useful with the shell that can have a roughened surface that can catch on soft tissue upon insertion.
When the cup holder is designed to mate with shells with threaded drive holes a threaded stud is captured within the body of the cup holder/tip. The threaded stud can be rotated clockwise or counter-clockwise to thread onto or off of shell implants. A cup holder/tip could be designed to mate with other shell designs. Specifically, the cup tip could be modified to have an expanding collect that could engage a smooth bore feature in a shell. These cup tips would be similar to those discussed below for holding shell inserts.
Some shells have a cluster of screw holes that need to be positioned in a specific location in reference to the curved shell positioner/impactor. There are several methods for orienting the screw holes with a curved shell positioner/impactor. One method is to thread the shell on to the cup holder/tip and positioner/impactor assembly, disassemble the shell/cup holder combination from the shell positioner/impactor preferably by pressing a button, reorienting the shell with the screw holes in the correct orientation, and reconnecting the shell/cup holder to the shell positioner/impactor. Another method for orienting the screw holes requires the surgeon to thread the shell partially on to the cup tip. By holding the shell in the correct orientation in reference to the shell positioner/impactor, the surgeon can then lock the shell and cup holder together by rotating a knob.
Polyethylene insert holders are designed to mate with the bearing surface of a polyethylene bearing insert. In one typical design, a silicone ring is captured between four components: a hex fitting, a spherical head, a compression ring and a body. When the internal hex fitting is rotated clockwise the silicone ring is squeezed between the spherical head and the compression ring causing it to protrude and create a friction lock with the polyethylene insert. The friction lock allows the user to turn, push and pull the insert which facilitates the assembly of the polyethylene insert into the shell.
Ceramic insert holders are designed to mate with a titanium outer sleeve in which a ceramic bearing insert is typically mounted. A holder is provided in which a collet is captured between two components: a hex fitting and a body. When the internal hex fitting is rotated clockwise the collet is expanded and creates a friction lock with the titanium sleeve of the ceramic insert. The friction lock allows the user to turn, push and pull the ceramic insert that facilitates the assembly of the ceramic insert into the shell.
Modular alignment guides have been developed that mate with the reamer handle and shell positioner/impactor. The modular alignment guides have a mechanism that allows the user to easily connect/disconnect the alignment guides from the acetabular instrument and to index the alignment guide around the axis of the instrument into the preferred position. It is preferred to be able to switch between a mechanical and navigation-based alignment guide. A navigation guide typically has a tracker with light emitting diodes that can be tracked via an optical system in the operating room. This allows the user to determine which method of alignment will be used and assemble the necessary guide. This in turn decreases the number of instruments in surgery.
In the preferred alignment guide embodiment, the mechanism is actuated by pressing a button that forces the translation of a locking pin perpendicular to the translation of the button. With the button pressed, the user can assemble the alignment guide to the guide fixture over the machined flats of the guide fixture. After passing the flats, the alignment guide can be rotated around the guide fixture to the preferred location. Once the preferred location is reached, the button is released and a lock pin engages the mating feature such as a bore in the guide fixture. The lock pin is spring-loaded into that position. In order to remove the alignment guide the operations are reversed.
Currently alignment guides designed for curved acetabular instruments are positioned in the same plane as the curve of the curved body. It is preferred to be able to position alignment guide independent of the curved body. The curved body should first be positioned to minimize impingement and then the alignment guides can be positioned to optimize their functionality. For a mechanical alignment guide this would involve positioning it so that it is perpendicular to the floor or patient. For a navigation-based alignment guide the user would position it to maximize visibility to the navigation cameras and to optimize the weight distribution of the navigation tracker.
While in the preferred system a separate reamer handle and a positioner/impactor is provided, it may be desirable to combine the two instruments into one instrument. This might be preferred because it would reduce the number of instruments in surgery and reduce the cost and weight of instruments. This may be accomplished through the use of modular attachments on either end of a curved body. A modular reamer locking mechanism is provided that attaches to the curved body in similar fashion to the modular holders. The main difference is that the modular reamer holder would not have a contrasting torque force supplied by the curved body. The modular reamer holder rotates freely around the curved body when torque is applied internally through the drive train. A modular impact handle can also be provided that connects with the same fitting that the power reamer attaches. The locking mechanism could be similar to those used in the modular holders. This modular impact handle would apply torque internally from a knob to the drive fitting then to the drive train of the curved instrument and would apply torque externally from the handle itself to the curved body. Axial forces would be translated from the knob to the handle to the curved body.

Curved acetabular positioner, impactor and reamer handle


The invention is a piece of firefighting equipment called a piercing nozzle. The piercing nozzle comprises a hollow tube connected to a hose and adapted for conveying water or other fire suppressant fluid near a pointed head adapted to penetrate a barrier and to release the water or fire suppressant fluid in an adjoining room. The pointed head contains a plurality of holes angled in various directions so as to spray the fire suppressant fluid over a wide area in the adjoining room so as to protect firefighters from flames or superheated air when they enter the adjoining room. The pointed head may be shaped like a cone attached to which is a plurality of sharp blades designed to facilitate penetration of the barrier. Attached to the hollow tube is a sliding weight with handles used for pounding the pointed head through the barrier.

The invention is a firefighting device, which enables firefighters who need to penetrate a wall or door in the process of firefighting to inject water or other fire suppressing fluid into a room beyond the wall or door in order to extinguish a fire or reduce the temperature of superheated air, which may exist beyond the door or wall. After use of the firefighting device, the firefighters may safely break down the door or wall without the risk that flames or superheated air will escape through the opening created by breaking down the door or wall, thus injuring the firefighters. The invention also has electrical insulation on its critical parts including the handles held by the firefighter to reduce the risk of electric shock to the firefighter in case the piercing nozzle contacts an electric wire inside the door or wall in the process of penetrating it.
Firefighting equipment includes hoses and nozzles of various kinds designed to pour water or fire suppressant fluid on an open area visible to the firefighters.
Firefighting equipment also includes hatchets, axes and other tools designed to break down doors or walls. However, when hatchets or other similar devices are used to break down the wall, fire or superheated air may escape from the adjoining room and burn the firefighters before they can use a hose or nozzle to reduce or extinguish the fire on the other side of the wall. Additional products that are available include a ram apparatus that is forced into a closed room or space by way of hitting it rear portion with a sledgehammer, similar to a hammer hitting a nail.
The ram approach has numerous disadvantages including that the use of a sledgehammer is itself dangerous. Swinging a 20-pound sledge in wet, dangerous and chaotic surroundings is likely to injure the person using the hammer or the person holding the ram. Also the procedure requires that the sledge (a separate tool) be carried with the ram. Further the ram method requires at least two people for its operation.
The invention is novel because it addresses the shortcoming of the prior methods, and gives a safe means of piercing a wall or door, to then suppress the potential life threatening circumstances that may await the firemen on the other side. All of this is done in a self-contained apparatus that can be operated by one individual. The piercing nozzle allows the introduction of the suppression fluid without subjecting the firemen to the superheated air and toxic smoke.
The invention comprises a hollow tube, a sharp pointed head on one end of the tube, and a sliding weight, which moves back and forth along the tube, so that the impact of the sliding weight against stops on the tube drives the pointed head and tube through a wall or door. Also the weight has the ability to be used to remove the tube if it gets stuck during its use. The pointed head, or the end of the tube, has holes, which spray water, introduced into the tube at the rear end of the tube, or other firefighting fluid into the area beyond the door or wall.
The objects of the present invention are:
1. To help firefighters gain access to an adjoining room behind a door or wall safely without the risk of fire or superheated air burning them when they create an opening in the door or wall.
2. To efficiently extinguish or suppress fire which may exist behind a door or wall with almost no danger to the firefighters.
3. To make a small initial opening in a door or wall for the purpose of injecting water or fire suppressing fluid into an adjoining room.
4. To provide a light-weight, small, portable device for penetrating a door or wall capable of operation by one person and adapted for connection to a water hose or similar source of firefighting fluid.
5. To provide protection from electric shock to the firefighter operating the device in case the device contacts an electrical wire in the process of penetrating the door or wall.
6. To provide a very sharp device for easily penetrating a door wall without undue hand pressure from the operator.
7. To provide a nozzle, which will spray water or fire suppressant fluid in many different directions once it has penetrated a wall or door.
8. To provide a wall or door penetrating device which does not require electric or other power, but can be operated easily by hand by a single firefighter.
9. To provide a single apparatus, with all of its essential elements, so that the piercing operation may be accomplished, without the worry of losing essential operating components.
10. To provide an apparatus to anticipate the needs of firefighters, in the midst of trying to put out a fire, that is both simple to use and with options to address the foreseeable hazards such as having the apparatus get wedged in a location and being able to use the same weight used to drive the apparatus into the door or wall as an efficient tool to remove the apparatus
Still further objects and advantages will become evident from the detailed description of the invention, and the drawings.


A retreaded tire comprised of a tread and carcass with an intervening rubber layer, conventionally referred to as a cushion, wherein the tread has an oil rich rubber-based adhesive on its inner surface at the interface between said tread and cushion. Said oil rich rubber based adhesive is free, or substantially free, of volatile organic compounds, particularly volatile organic solvents. Alternately, the oil-rich rubber-based adhesive may contain oil and volatile organic solvent wherein oil is the major component insofar as the oil and solvent is concerned.

A retreaded tire comprised of a tread and carcass with an intervening rubber layer, conventionally referred to as a cushion, wherein the tread has an oil rich rubber-based adhesive on its inner surface at the interface between said tread and cushion. Said oil rich rubber based adhesive is free, or substantially free, of volatile organic compounds, particularly volatile organic solvents. Alternately, the oil-rich rubber-based adhesive may contain oil and volatile organic solvent wherein oil is the major component insofar as the oil and solvent is concerned.
Historically, a rubber tire is retreaded by first abrading away its tread and buffing a surface of the remaining rubber carcass.
A strip of sulfur vulcanizable, unvulcanized rubber composition is then applied onto and circumferentially around the periphery of the buffed, cured rubber tire carcass.
Such rubber composition strip is conventionally referred as a xe2x80x9ccushionxe2x80x9d.
Over the cushion may then be applied a pre-cured, shaped rubber tread, to which a vulcanizable or unvulcanizable, and preferably a sulfur vulcanizable, unvulcanized rubber-based adhesive has been applied to the inner surface of the tread to enhance the interfacial adhesion between the tread and aforesaid cushion.
The resulting tire assembly is then conventionally encased in a cured butyl rubber envelope, a vacuum drawn on the envelope, and the enveloped tire assembly inserted in an autoclave and the assembly vulcanized therein at a temperature of, for example, about 130xc2x0 C. to produce the retreaded tire.
Such method of tire retreading with a pre-cured tread and vulcanizable cushion over an abraded tire carcass is well known to those having skill in such art.
Historically the aforesaid rubber-based adhesive may be applied to the tread stock as a volatile organic solvent solution of the adhesive and then allowed to dry prior to application of the tread to the aforesaid cushion.
However, it is sometimes desired to provide such adhesive, and the accompanying application of the adhesive to a pre-cured tire tread, in a retreading operation without volatile organic compounds, or at least substantially free of volatile organic compounds, which may sometimes be referred to as xe2x80x9cVOC""sxe2x80x9d.
In the description of this invention, the term xe2x80x9cphrxe2x80x9d as used herein, and according to conventional practice, refers to xe2x80x9cparts of a respective material per 100 parts by weight of rubber elastomerxe2x80x9d. In the description of this invention, the terms xe2x80x9crubberxe2x80x9d and xe2x80x9celastomerxe2x80x9d can be used interchangeably, unless otherwise distinguished.
The terms xe2x80x9crubber compositionxe2x80x9d, xe2x80x9ccompounded rubberxe2x80x9d and xe2x80x9crubber compoundxe2x80x9d can be used interchangeably to refer to xe2x80x9crubber which has been blended or mixed with various ingredients and materialsxe2x80x9d and the terms xe2x80x9ccurexe2x80x9d and xe2x80x9cvulcanizexe2x80x9d may also be used interchangeably herein, unless otherwise noted and such terms are well known to those having skill in the rubber mixing or rubber compounding art.
In a pneumatic tire retreading operation where a tire carcass is obtained, preferably an abraded vulcanized rubber tire carcass prepared by abrading away its tread and buffing the peripheral surface of the remaining cured tire carcass, to which a strip of a sulfur vulcanizable, unvulcanized rubber composition, or cushion, is circumferentially applied to the abraded peripheral surface of said tire carcass, and to which a pre-cured rubber tread strip, which has a vulcanizable or unvulcanizable, but preferably a sulfur vulcanizable, unvulcanized rubber based adhesive on its inner surface, is applied to said cushion, wherein said rubber based adhesive is located at the interface between said cushion and said tread stock, and wherein the resulting assembly is vulcanized at an elevated temperature to form a retreaded tire; an improvement wherein said adhesive is comprised of an oil rich rubber composition
(i) which contains from about 150 to about 1400, alternately about 400 to about 1000, phr of rubber processing oil and is exclusive of volatile organic compounds; or
(ii) which contains from about 150 to about 1400, alternatively about 400 to about 1000, phr combination of rubber processing oil and volatile organic solvent wherein the weight ratio of said oil to said solvent is in a range of about 1/0.05 to about 1/0.66, preferably about 1/0.05 to about 1/0.33; wherein said solvent is evaporated from said adhesive layer prior to application of said pre-cured tread strip to said cushion layer.
Accordingly, in one aspect of this invention, a retreaded tire is provided as a concentric circular laminate comprised of:
(a) a cured rubber tire casing, or carcass, having an abraded, or buffed, circumferential peripheral surface;
(b) a concentric, circular, unvulcanized rubber cushion layer having an inner surface and outer surface, wherein the inner surface of said cushion layer is positioned on said outer peripheral surface of said tire casing; and
(c) a pre-cured rubber tire tread strip having an inner surface and an outer surface, wherein said inner tread surface contains an unvulcanized oil-rich rubber-based adhesive layer thereon and wherein said pre-cured tread strip is circumferentially positioned on the outer surface of said positioned cushion layer with said adhesive layer therebetween to create a tire assembly, wherein said adhesive layer is comprised of an oil-rich rubber-based composition:
(i) which contains from about 150 to about 1400, alternately about 400 to about 1000, phr of rubber processing oil and is exclusive of volatile organic compounds; or
(ii) which contains from about 150 to about 1400, alternatively about 400 to about 1000, phr combination of rubber processing oil and volatile organic solvent wherein the weight ratio of said oil to said solvent is in a range of about 1/0.05 to about 1/0.66, preferably about 1/0.05 to about 1/0.33; wherein said solvent is evaporated from said adhesive layer prior to application of said pre-cured tread strip to said cushion layer.
A retreaded tire is then provided by heating the said tire assembly to an elevated temperature to vulcanized said adhesive cushion layers.
Usually an elevated temperature in a range of about 100xc2x0 C. to about 150xc2x0 C. is used for such vulcanization.
The oil-rich, rubber-based, adhesive layer is the oil-rich adhesive provided by this invention.
A significant aspect of the invention is the use of a substantial amount of oil which, in the adhesive, is a rubber processing oil and is therefore compatible with the elastomer composition of the cured elastomer of the tread and unvulcanized elastomer composition of the cushion and with the cured elastomer composition of the tire carcass casing to which the tire tread is applied.
This aspect of the invention relies upon the high level of oil content to provide for solubilizing the rubber of the adhesive to permit application of the adhesive to the inner surface of the pre-cure tread and, after sufficient migration of the oil into the cured tread strip, to also provide protection from premature oxidation of the inner tread surface from the atmosphere and impart a tacky surface to the associated surface tread prior to the actual application of the tread to the cushion.
Suitable oils for this adhesive composition are typical rubber processing oils of viscosities (ASTM D 2161, at 99xc2x0 C.) ranging from about 30 to about 70 SUS and preferably 30 to 45 SUS; of clay bed analyses (ASTM D 2007) ranging from about 10 to about 90 wt % aromatics, preferably 20 to 50 wt % aromatics; and saturates ranging from about 90 to about 10 wt % saturates, preferably 80% to 50% saturates; aniline point (ASTM D 611) ranging from about 11 to about 121xc2x0 C. and preferably 15 to 82xc2x0 C.
Where a volatile organic solvent is used in the oil rich adhesive of this invention, representative solvents are, for example, hexane, heptane and mixtures of liquid hydrocarbons containing from 6 to and including 7 carbon atoms. Preferably, such solvents have a boiling point at atmospheric pressure in a range of about 30xc2x0 C. to about 130xc2x0 C.
The adhesive rubber composition may be comprised of various rubbers such as, for example, diene-based rubbers as polymers and copolymers of conjugated diene monomers having from 4 to 10 carbon atoms (e.g. 1,3-butadiene and isoprene), rubbers as copolymers of conjugated diene monomer(s) having from 4 to 10 carbon atoms copolymerized with a vinyl substituted aromatic monomer(s) having from 8 to 12 carbon atoms (e.g., styrene and alpha methylstyrene), and the like, as well as blends thereof. Such rubbers generally contain various antioxidants, fillers such as carbon black, oils, sulfur, accelerators, tackifying resins, antioxidants, stearic acid, antiozonants and the like in conventional amounts.
Representative of such rubbers are, for example, cis 1,4-polyisoprene (natural or synthetic), cis 1,4-polybutadiene and styrene/butadiene copolymer rubber.
Preferably, such rubber is, or is at least primarily comprised of cis 1,4-polyisoprene rubber, preferably natural rubber. For example, such rubber may be natural cis 1,4-polyisoprene rubber or a blend of natural cis 1,4-polyisoprene rubber and at least one of said diene-based rubbers so long as at least 51 weight percent of the rubbers is the natural rubber.
Various rubber reinforcing carbon blacks may be used for the adhesive composition such as, for example, ASTM D 3849 grades N550 and N650 and the like.
The adhesive compositions of this invention can optionally, but preferably, include one or more compatible tackifying agents which are utilized in an effective amount to promote good tack (e.g., pressure sensitive tack) with vulcanized elastomeric substrates, such as the tread or even a buffed carcass surface, if desired, and also with uncured, vulcanizable elastomeric substrates (i.e. non-vulcanized or at least substantially non-vulcanized) such as the said cushion layer. The tackifying resins which can be utilized are generally well known to the art and to the literature and generally include rosin and its derivatives and various hydrocarbon resins. The rosin group comprises rosins, modified rosins and their various derivatives such as esters. The hydrocarbon resin group comprises polyterpines, synthetic hydrocarbon resins, and various modified or special resins which are primarily phenolics. Tackifier resins are described in more detail in the Handbook of Pressure-Sensitive Adhesive Technology, edited by Donatas Satas, Van Nostrand Reinhold Company, 1982, Chapter 16, pages 353-369, which is hereby fully incorporated by reference.
Another and preferred type of tackifier for the adhesive are the various phenol-formaldehyde resins. Such resins generally have a number average molecular weight of 2,000 or less. Typically, alkyl phenols are used rather than phenol itself since the alkyl group improves the miscibility of the resin with the rubber. The existence of phenol-formaldehyde tackifiers are well known to the art and to the literature, e.g., xe2x80x9cResins Used in Rubbersxe2x80x9d by Paul 0. Powers, Rubber Chemistry and Technology, Vol. 36, pages 1542-1562, (1963), and xe2x80x9cRole of Phenolic Tackifiers in Polyisoprene Rubber,xe2x80x9d by F. L. Mangus and G. R. Hamed, Rubber Chemistry and Technology, vol. 64, pages 65-73 (1991).
The present invention relates to a vulcanizable or unvulcanizable system, but the preferable vulcanizable system relates to sulfur cure systems and include one or more cure accelerators in the adhesive composition for this invention. Suitable amounts of sulfur and/or sulfur donor-type compounds generally range from about 1 to about 10 and preferably from about 2 to about 5 phr. The amounts of sulfur vulcanization accelerator generally range from about 0.2 to about 4 and preferably from about 0.5 to about 2.0 phr. Various sulfur accelerators can be used such as aldehyde-amine accelerators, e.g., the reaction product of butyraldehyde and aniline, amines such as hexamethylene tetramine, guanidines such as diphenyl guanidine, thioureas, sulfenamides, thiazoles, and the like. Activators such as zinc oxide, stearic acid, litharge, magnesia and amines can also be used in conventional amounts to attain good crosslinking efficiency.
The oil rich adhesive compositions of the invention can also include conventional amounts of various known rubber compounding ingredients such as processing aids, stabilizers, antidegradants, and the like. Suitable antioxidants include alkylated hindered phenols, alkylated or arylalkylated diphenylamines, aminophenols, dialkyl- diaryl- or mixed alkyl-aryl-p-phenylenediamines, and aniline plus ketone or aldehyde condensation products.
The uncured elastomeric adhesive composition of the present invention can be vulcanized by heat or radiation according to any conventional vulcanization process. Typically, the vulcanization is conducted at a temperature ranging from about 100xc2x0 C. to about 250xc2x0 C. or preferably from about 120xc2x0 C. to about 170xc2x0 C. for a time period ranging from about 1 to about 300 minutes.
The present invention can be utilized to form a retreaded tire, as a laminate of tread, cushion and carcass, for various types of vehicle tires such as passenger car tires, light and medium truck tires, off the road tires, and preferably is utilized in forming retreaded laminates for aircraft and medium truck tires.
To prepare the highly oil rich adhesive compositions, a conventional masterbatch may be first prepared by conventional mixing techniques including, e.g., kneading, roller milling, extruder mixing, internal mixing (such as with a Banbury(copyright) mixer), etc. Such masterbatches may contain conventional amounts of rubber processing oil (0 to about 100 phr oil). The sequence of mixing and temperatures employed are well known to skilled rubber compounders, the objective being the dispersion of fillers, activators, curatives in the polymer without excessive heat buildup.
Additional rubber processing oil may then be incorporated into the masterbatch in mixers designed for lower viscosity materials such as paints or caulks. Such mixers include those with high speed dispersion blades such as a churn.
Curatives may be incorporated into the conventional masterbatch, or during the subsequent addition of the extra oil.

Retreaded tire having tread with oil rich rubber-based adhesive


A flexible light pipe consisting of a light-transmitting core, a cladding, and a sheathing is described which, by suitable choice of cladding and sheathing materials, exhibits a combination of good flexibility for bending and shaping whilst retaining good resistance to kinking or other interruptions which can adversely affect transmission of light.

This invention relates to an improved composition for cladding and sheathing a flexible potentially light-conducting core to form a flexible light pipe ("FLP"), and the improved FLP composition which results. The invention also relates to a FLP having a core diameter of a least 3 millimeters, useful for conveying visible light and which remains highly flexible and transparent under a wide range of use conditions, yet is resistant to kinking and to deformation which would alter cross-sectional dimensions of the FLP and adversely affect the transmission of the supplied light.
Most plastic light pipes or light guides known to the art are based on single or bundled fibers of optically clear rigid polymers like poly(methyl methacrylate), although a few composites are known based on cores of flexible, optically clear polymers of lower glass temperature, such as poly(alkyl acrylates). Several patents exist to very soft light pipe, which is so low in modulus as to be deformable under use conditions where it is not protected in a solid enclosure.
U.S. Pat. Nos. 5,406,641 and 5,485,541, both herein incorporated by reference, teach a process for preparing such a flexible light pipe, preferably from a crosslinked poly(alkyl acrylate) core, which core is enclosed in a polymeric cladding and further protected by a polymeric sheathing. These applications teach a variety of cladding materials with refractive indices lower than the polyacrylate core, preferring fluorinated polymers and exemplifying terpolymers of perfluoroalkyl vinyl ether/tetrafluoroethylene/hexafluoropropylene (FEP) and of vinylidene fluoride/tetrafluoroethylene/hexafluoropropylene (THV). These cited applications further teach a number of polymers useful as sheathing, such as polyethylene, linear low density polyethylene, polypropylene, and polystyrene.
As the development of FLP has continued, certain specific uses, such as supplying illumination through a tortuous path with many bends or curves, or where the FLP must conform to the motion of a flexible support frame or body, have been identified, which uses require a combination of flexibility and resistance to deformation beyond those taught or suggested by the existing art. In particular, there has been identified a need for combination of cladding and sheathing which will give the highest combination of flexibility and deformation resistance, two properties difficult to find in a cladding/sheathing combination, to the clad and sheathed light pipe whilst maintaining resistance to kinking and further protecting the surfaces of the core, and still retaining the optical properties of the core/cladding system i.e., conduction of light through the desired distance without excessive loss. Improved flexibility alone, such as may be exhibited by a low modulus FLP in a low modulus cladding/sheathing combination, is not sufficient for achievement of resistance to kinking or resistance to deformation under low load, also necessary for the envisioned uses for this special grade of FLP.
I have found a combination of cladding and sheathing which is effective for this purpose and superior to those taught in the prior art. Specifically, I have discovered a flexible light pipe having a visible light transmission loss of less than 2 decibels/meter, comprising;
a) a crosslinked core polymer of diameter at least 3 mm; PA1 b) a fluoropolymer cladding whose refractive index is lower than that of the core; PA1 c) a sheathing for the core/cladding combination which in combination with the core and cladding will (a) withstand (as measured by the D.sub.f value described below) a 180 degree bend at 20.degree. C. at a bend radius equal to or less 2 times the core mixture diameter; (b) exhibit a drape test arc width (as measured by the DW value described below) less than 15 times the diameter of the drape rod. PA1 a) from about 95 to about 99.9 weight percent, based on the crosslinkable core mixture weight, of an uncrosslinked copolymer having weight average molecular weight from about 2,000 to about 250,000 daltons, the uncrosslinked copolymer comprising: PA1 b) from about 0.1 to about 5 weight percent, based on the crosslinkable core mixture weight, of a reactive additive comprising water and a dialkyltin dicarboxylate. PA1 a) the bulk monomer is ethyl acrylate; PA1 b) the reactive monomer is 3-methacryloxypropyltrimethoxysilane; and PA1 c) the dialkyltin dicarboxylate is dibutyltin diacetate.
A preferred embodiment is wherein the fluoropolymer cladding is vinylidene fluoride/tetrafluoroethylene/hexafluoropropylene terpolymer; an especially preferred embodiment is wherein the terpolymer cladding contains 50-55 weight percent vinylidene fluoride, 28-32 weight percent tetrafluoroethylene and 16-20 weight percent hexafluoropropylene.
Another preferred embodiment is wherein the sheathing contains a thermoplastic elastomer, more preferably a styrene/hydrogenated butadiene block copolymer or a styrene/hydrogenated butadiene/styrene block copolymer. Another preferred embodiment is wherein the sheathing further contains a polyolefin, more preferably linear low density polyethylene. An especially preferred embodiment is wherein the sheathing is a blend of a styrene/hydrogenated butadiene block copolymer and linear low density polyethylene in the weight ratio 1:1 to 6:1; an even more especially preferred ratio is 1:1 to 4.1.
The flexible light pipe itself must be capable of being bent and shaped, often repeatedly, without fracture or distortion, as well as retaining its ability to be conductive of light. Several chemical approaches to formation of the light-conducting core, such as polymerization of acrylate esters, of certain silicone polymers, certain polyesters, and the like, may be employed. The method to crosslink may be varied, such as the use of functionalized monomers, or of ionizing radiation, and the like. The FLPs of the invention have useful optical properties and a visible light transmission loss of less than about 2 decibels ("dB") per meter (i.e. 2000 dB per kilometer), preferably less than about 1.0 dB/m (ca. 93% transmittance per foot), more preferably less than about 0.70 dB/m, even more preferably less than about 0.65 dB/m, and most preferably less than or about 0.50 dB/m.
However, to obtain a cured composite which is a FLP having core diameter >3 mm and having flexibility at or below ambient temperatures, the copolymer core should have a T.sub.g (glass temperature) equal to or less than about 0.degree. C., preferably less than about minus 10.degree. C.
"Flexibility" of a light pipe or FLP is defined at a given use temperature. For the FLP of the Bigley et al. invention, flexibility at room temperature (about 20.degree. C.) meant the ability of the FLP to withstand a 180 degree bend without cured core mixture fracture at a bend radius equal to or less than five times ("5d") the core mixture diameter ("1d") of the FLP. Such a fracture results in light transmission loss, rendering the FLP ineffective. The radius can be determined, for example, by use of a mandrel. However, there are many uses, such as those taught below, for which the degree of flexibility taught by Bigley et al. alone is insufficient. The Bigley test may define adequate resistance to kinking, but it does not relate to the ability of the FLP to take a contoured shape and to maintain that shape.
To define the attributes of the improved FLP, a drape test or the like is required, which relates to the ability of the FLP to drape over a surface without too high a stiffness, which leads to imperfect shaping for the desired use. The drape test measures the ability of the FLP to hang over a specified mandrel with the ends of the FLP being as close together as allowed by the flexibility of the core and cladding components. High distances, relative to the mandrel size, indicate the FLP is too stiff for the specific purposes of a highly flexible, yet kink-resistant, light pipe.
"Softness" of the FLP core (cured crosslinkable core mixture) is described in Bigley et al. as a desirable property because it is related to breakage and fabrication techniques. Softness is defined herein by a "level of compressibility" discernible by a modified Shore "A" test described below. A degree of softness, typically a Shore "A" value <90, is desired to enable cutting of a FLP by a hand held instrument, such as a scissors or knife, in the field (i.e. not requiring motorized instruments or factory equipment) and to facilitate the flush fit against other light conduit such as a glass pipe, glass rod, connector, light pipe or an FLP. However, a Shore hardness <90 does not fully define the parameters required to the improved FLP described herein.
Especially preferred compositions and processes for preparing flexible light pipe are disclosed in the Bigley et al. patent and allowed patent, incorporated by reference. Specifically, there is provided a composition for a light pipe crosslinkable core mixture which comprises:
i) from about 80 to about 99.9 weight percent, based on the uncrosslinked copolymer weight, of a bulk monomer selected from methyl acrylate, ethyl acrylate, normal butyl acrylate, or mixtures thereof, PA2 ii) from about 0.1 to about 20 weight percent, based on the uncrosslinked polymer weight, of a functionally reactive monomer selected from 3-methacryloxypropyltrimethoxysilane or vinyltrimethoxysilane; and
Particularly preferred is the composition wherein:
Most preferred is the uncrosslinked copolymer derived from about 94 to about 98 weight percent ethyl acrylate and from about 2 to about 6 weight percent MATS.
To obtain the optics for useful light pipe, a cladding is required with a refractive index lower than that of the core. Further, the cladding needs to be able to contain the core polymer effectively. Depending on the manufacturing process, the cladding may contain the monomers which are polymerized to form the core, the core polymer only partially polymerized, the core polymer polymerized but not crosslinked, and/or the fully crosslinked core polymer. Many cladding materials are known for this purpose, especially fluoropolymers which are of lower refractive index than most of the core polymers known to the art.
For the present purposes, the cladding need also be flexible, to avoid kinking, tearing, stretching or any defect which will alter the light-carrying characteristics of the clad/core light pipe. This property can be approximated by physical properties of the cladding alone, but measurement of the flexibility of the core and cladding in combination is the best judgment of utility. Especially useful for this purpose are non-crystalline terpolymers of vinylidene fluoride/tetrafluoroethylene/hexafluoropropylene, more especially in the compositional range of 50-55 weight percent vinylidene fluoride, 28-32 weight percent tetrafluoroethylene and 16-20 weight percent hexafluoropropylene.
The ability to resist deformation leading to loss of optical transmission is tested at 21.+-.1.degree. C., using an instrument designed for smoothly varying the bend radius and providing a failure criterion of core material fracture. The test apparatus comprises an 8" (20.3 cm.) diameter, six-jaw lathe chuck situated horizontally on a flat surface. Four jaws, positioned to define a 180.degree. bend, are used to approximate an "adjustable diameter mandrel." Each jaw has two azimuthal slots cut in different radial positions to hold a light pipe, which pipe is sheathed. The bend diameter range which can be investigated by the device is from about 2.5 to 20 cm., measurement being made from center to center of the pipe at the 180.degree. bend. Samples are 100 cm. in length. The sample is then placed into appropriate slots in the fixture, which had been preset to the desired test radius. To maintain sample geometry (and the relevance of the measured intensities), the entire test is conducted without unhooking either the light source or the detector from the sample ends. A mold release agent, such as "Mold-Wiz M-57" or other non-destructive lubricant, is sprayed onto those portions of the chuck assembly which contact the FLP samples between measurements of different samples, so that there will not be a problem with adhesion of the FLP to the jaws, which would distort the results.
The first measurement of transmitted light intensity is made at a 20 cm. diameter bend, and at each successive decrease of one centimeter in diameter. When a value of 12 cm. is reached, the design of the particular holder utilized required moving the sample to a second series of azimuthal slots which are closer to the center of the chuck, or the jaws would converge before the failure diameter could be measured for very flexible samples. Failure is designated as the value of the diameter (D.sub.f) for which the transmission dropped to 50% of that recorded at 20 cm. for the same sample. Lower values of D.sub.f thus indicate samples which are more resistant to kinking. A value of D.sub.f which is equal to or less than the core mixture diameter (i.e., a bend radius equal to or less 2 times the core mixture diameter) is an acceptable value of resistance to kinking or other deformation. The very soft sheathings examined do not achieve this tight bending without deformation, as indicated by loss of light transmission.
An alternate test for studying resistance to kinking, but somewhat less discriminatory, is again to test the FLP without unhooking either the light source or the detector from the sample ends, and wrapping around a solid mandrel which distributes force evenly, thus minimizing kinking of the FLP under study. The intensity is monitored prior to wrapping the sample, and then while the sample is wrapped around a 11.2 cm. mandrel. Subsequently, the sample is wrapped around a 7.8 cm. mandrel and re-measured. The % of transmitted light (% T.sub.7.8) at the smaller mandrel (relative to the larger) is recorded. The higher the value, the less distortion or kinking of the sample.
The ability of the core/clad/sheathing composite to form or drape or take the shape desired is measured by a drape width determination. Samples of the same composition as reported above in the mandrel test are cut to lengths of 6 ft. (180 cm.), then fastened to a straight steel pipe and annealed at 90.degree. C. for 12 hours to remove any curvature from processing or storage. The samples are then cooled to the test temperature and maintained there for several hours, removed from the steel support, and are hung by centering on a horizontal 1.5 cm. diameter pipe or rod. The width of the resultant arc (inside edge to inside edge) is measured (DW value) at a distance of 5.5 cm. below the balance point (the top of the supporting horizontal pipe or rod). Samples are run in duplicate. A value of DW of 15 times or less the diameter of the horizontal drape rod indicates adequate flexibility for the uses required.
Light pipes and FLPs are often coupled to high-flux illuminators, such as the GE Light Engine.TM., for conveying bright light to a desired use point (end-lit applications) or illumination or decoration utilizing the length of the light pipe (side-lit, side-emission or "neo-neon" applications). Other useful sources include, but are not limited to, direct solar light, focused solar light, fluorescent lamps, high-, medium- and low-pressure sodium lamps, quartz-halogen, tungsten-halogen and incandescent lamps.
Many envisioned uses of flexible light pipe do not require the combination of flexibility and resistance to deformation taught herein. Applications in the following areas where a combination of flexibility of resistance to deformation is required include: certain automotive and transportation uses, such as in dashboard lights, accent lights, map readers, certain interior lighting of boats, trailers, campers and airplanes, and the like; certain retail lighting uses, such as in point of purchase displays, and the like; architectural lighting, traffic lights, mining lights, such as hard hat lighting; to remote source systems, such as in prison cells, hazardous environments, zoos, aquariums, art museums, and the like; residential lighting, as in novel lighting for showers; specific task lighting, such as auto mechanic lighting, surgeon/dentist lighting, "high tech" manufacturing lighting, endoscopes, photographic uses, and the like; and other specialty lighting. Other possible uses include: ionically conductive multilayer films with flexible cores for electrochromic displays, non-metal resistance heaters, touchpads and artificial muscles; chemiluminescent devices; and the like.
Other embodiments of the invention will be apparent to those skilled in the art from a consideration of this specification or practice of the invention disclosed herein. It is intended that the specification and examples be considered exemplary only, with the true scope and spirit of the invention indicated by the claims, following.


A shifting device for a multi-speed hub for a bicycle that, comprises a hub axle, a driver, a hub sleeve and an epicyclical transmission with an annulus, a plant carrier, planet wheels and a sun wheel, a control device for changing the gear ratios between the multi-speed hub and a remote control. The gear change is executed exclusively by the lifting out or engagement of pawls which can be controlled by means of a shift unit. The shift sleeve and bushing have projections and gaps and can slide under a respective foot of the pawl thereby enabling the pawls to be forcibly disengaged. An advantage of the invention is the ability to disengage the respective pawl even under load without the need to employ relatively large control forces by means of the remote control.

The invention relates to a shifting device for a multi-speed hub.
German Patent DE 42 29 023 disclose a multi-speed hub which has a shifting device between two locking-mechanism levels in a multi-speed hub which can be shifted backward and forward even under load. The shifting is achieved by propulsion pawls which are held forcibly in driving engagement, are arranged one above the other and have an angle of tooth engagement chosen such that the propulsion pawls slide out of engagement under load. A control disk can be displaced under the propulsion pawls, thereby alternately holding the pawls fast and locking them in their associated ratchet toothing. The control disk is taken along at the driving speed by means of a driver disk in the pawl carrier and has a rearward rotational idle travel relative to the propulsion pawls which is necessary in order to use the initial angular degrees when braking by backpedaling to lift out the forcibly held propulsion pawls. Such a shift mechanism has the advantage, by virtue of the division of the power transmitted into a driving component and an inward-directed control component, of only requiring the management of the smaller control component, even under load.
The present invention is in a greatly simplified and low-cost shift unit for a multi-speed hud which can likewise disengage the pawls of the pawl-controlled hub under load and maintain them in this disengaged state.
The invention is formed with a shift sleeve, which is arranged around a hub axle, and a shift bushing connected rotatably to it, the sleeve and the bushing having on their respective end faces shift projections which are separated by gaps of sufficient width to slide under the respective pawl to be lifted out. The pawl is enclosed on both sides by projections. Since the shift sleeve and the shift bushing each have a different and, in particular, slower rotational speed than the pawls, a projection which has slid in front of the pawl will slide under the latter due to the propulsive power of the driving torque from the rider and will lift out the pawl. The control force required for the above described shift operation is not particularly great but it must be considered that the profiles do not always approach the respective pawls in the desired manner. If a projection collides with a pawl, the latter cannot be lifted out by the projection if the applied torque is high. Only if the pawl is between two projections can the projection slide under the pawl and disengage the latter from its torque connection. However, the projection can lift the pawl out even when this pawl is not transmitting any significant torque. This advantage in terms of shifting, which is also present to allow shifting through the gear ratios when the transmission is stationary, is provided by additional bevels on the pawl. It is furthermore proposed to enhance the capability for shifting through the gears by arranging conical chamfers on the end faces of the projections and/or the gaps between the projections in addition to the bevels on the pawls, the alignment of the chamfers coinciding approximately with the bevels on the pawls. Finally, the projections of the profile on the shift bushing and on the shift sleeve have bevels which are arranged in the circumferential direction and which can act as a load-limiting means by virtue of the fact that the shift bushing or the shift sleeve is repelled by the pawls when large torques are being transmitted via the pawls. It is advantageous to connect the shift bushing and/or the shift sleeve to a rider-operated remote control by means of storage springs which allows a change in gear ratio only when a certain lift-out torque is reached and which delay the shift operation. It is possible, by means of the configuration of these storage springs, to define the desired lift-out torque, thereby avoiding excessive shifting shocks. The shift sleeve or the shift bushing will thus find another location for engagement under the pawl, which will be lifted out when the torque is reduced.
In a three-speed hub, a first pawl is mounted on the annulus and engages the toothing of the hub sleeve. Since the annulus necessarily rotates more rapidly than the planet carrier when the latter is being driven, it is necessary to couple the shift bushing to a coupling ring rotating at the rotational speed of the planet carrier. On the other hand, the shift bushing must be axially displaceable, something which can only be achieved by means of a shift component, which preferably is a thrust block connected to a remote control. The two movements described above can be imparted to the shift bushing on the one hand by virtue of the rotatable mounting of the shift bushing on the shift sleeve, which is connected in a rotationally rigid manner to the thrust block, and secondly by virtue of the mounting of the shift bushing in a slot in the coupling ring, which rotates more slowly when a fast gear has been selected than the pawl operatively connected to the hub sleeve.
If the connection between the driver and the planet carrier is likewise by way of a pawl, what has been stated above applies in as much as the pawl of the more slowly rotating planet carrier overtakes the profile of the shift sleeve, which is connected in a rotationally rigid manner to the hub axle but is axially displaceable, and provides the same lift-out conditions for the pawl as those described above in connection with the shift sleeve. To ensure operation during backpedaling, the pawls in the region of the foot, should have a contour such as a rounding or chamfer so that the pawls are lifted out and do not jam in the event that they have not yet been lifted out but are still in the region between the projections. Since there is no load on the pawls during backpedaling, the only point of importance is that the rounding should be sufficiently great.
Finally, it is advantageous not to maintain the shift bushing in an axially fixed position on the shift sleeve but to hold it by means of a storage spring since there, as described, brief hindrances to shifting have to be compensated for if it is required to be able to operate the remote control without resistance.
The object of the invention is therefore to provide a shifting device for a multi-speed hub which can perform the gear change while stationary and even under load without a significant increase in the control forces on a remote control.
The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of the disclosure. For a better understanding of the invention, its operating advantages, and specific objects attained by its use, reference should be had to the drawing and descriptive matter in which there are illustrated and described preferred embodiments of the invention.

Shifting device for a multi-speed hub for a bicycle


A first plate material is set on a work stage. The first plate material includes first components commonly connected to a first connection member. A second plate material is subsequently set on the work stage. The second plate material includes second components commonly connected to a second connection member. The second components are superposed on the corresponding first components. The first components as well as the second components can be handled as a one-piece component. It leads to an improved productivity. Heat surfaces of a heat block contact the second components. The connection members are prevented from thermal expansion. The constant intervals are reliably maintained between the adjacent first components and the adjacent second components.

1. Field of the Invention
The present invention relates to a method of heating superposed components, comprising superposing first and second components on a work stage, and allowing a heat block to contact with at least the second component so as to heat the first and second components. In particular, the invention relates to a heating apparatus utilized in the same method.
2. Description of the Prior Art
As conventionally known, a piezoelectric microactuator sometimes includes a pair of sheared piezoelectric elements. The piezoelectric elements in the form of a plate is interposed between a pair of electrode plates in the piezoelectric microactuator of this type. The electrode plates are individually adhered to the front and back surfaces of the piezoelectric element. A stationary microcomponent is adhered to one of the electrode plates, while a movable microcomponent is adhered to the other of the electrode plates. A thermosetting adhesive is in general employed to the adhesion. When a predetermined voltage is applied to the piezoelectric elements through the electrode plates, a relative rotation can be induced between the electrode plates, namely, between the microcomponents based on the shear of the piezoelectric elements.
The piezoelectric microactuator is often employed as a displacement controlling or positioning mechanism of a higher accuracy. A relative displacement or slippage should be avoided between the microcomponent and the electrode plate when both are adhered to each other. The microcomponent must be positioned at a higher accuracy relative to the electrode plate before actually heating the thermosetting adhesive between the microcomponent and the electrode plate. An expensive image recognition technique and an expensive positioning robot are required to achieve the accurate positioning of the microcomponent and the electrode plate. In addition, only a single set of the microcomponent and the electrode plate can be subjected to adhesion at a time.

Method of heating superposed components and heating apparatus therefor


An exemplary embodiment relates to a measuring device for measuring a current flowing in a first cable. The measuring device includes a measuring shunt in the form of a plate connected in series with the first cable and associated with a measuring electronic card connected to a data transmission cable. The measuring shunt further includes a measuring portion of resistive alloy coupled to connection portions on either side of the measuring portion. The connection portions are integrally formed with the measuring portion, and the first cable is secured to at least one of the connection portions of the measuring shunt.

The present disclosure relates to a device for measuring a current flowing in a cable, and more particularly to a power supply cable connected to a battery.
Measuring devices for monitoring the load on a battery are generally known and might include a shunt in the form of a plate connected in series with the cable for powering various pieces of equipment connected to the battery, the measuring shunt being associated with a measuring electronic card connected to a measurement data transmission cable.
Various embodiments of the above-mentioned measurement device are known. In particular, EP 1,238,288 discloses a measuring device integrated in a battery cable terminal in which the measuring shunt comprises a measuring portion of resistive alloy associated with a measuring electronic card, and connected to conductive connection portions along two opposite edges of the measuring portion, the connection portions both being supported by the battery cable terminal. Such a measuring device is complex and difficult to make. Therefore, its cost is high compared to the cost generally accepted for equipment of that type.
Likewise, U.S. Pat. No. 6,304,062 (Batson) discloses a current measuring device comprising a shunt connected between the terminals of two adjacent battery cells. Such battery cells need to have a structure that is specifically adapted to receive the Batson current measuring device, which results in the battery not being freely interchangeable.
An object of the disclosure is to provide a current measuring device that is simple in structure thereby enabling it to be made at low cost.

Device for measuring a current flowing in a cable