Abstract: An anchor 100 is provided for anchoring a reaction plate 62 to an actuator rod 60 in a spring brake actuator 10 having a tubular actuator rod 60. The anchor 100 comprises an expandable plug 102 received within an interior space of the actuator rod 60, a bolt 110 extending from the reaction plate 62 through the plug 102 and a washer 108 having a threaded central aperture 81 threaded onto the bolt 110 whereby the plug 102 is compressed between the washer 108 and the reaction plate 62 to expand into engagement with an interior wall 120 of the actuator rod 60. Preferably, the plug 102 is formed of an elastomeric material.

Abstract: A diaphragm for spring brake actuators includes an aperture that receives a threaded securement member such that the diaphragm is directly fixed to a push rod. In this way, misalignment between the push rod and the diaphragm is eliminated. To overcome any leakage through the aperture the diaphragm is formed with sealing beads compressed by the securement member to achieve a seal. Preferably, diaphragm plates are received on each side of the diaphragm, and the sealing beads are compressed by the securement member to achieve a seal between the securement member and the diaphragm plates. An adequate seal is thus achieved, while still allowing the direct connection of the diaphragm to the push rod by a threaded connecting member. The diaphragm plate on the power spring side of the diaphragm extends upwardly into a recess in the power spring plate, and is in facial contact in an axial direction with a surface of the power spring plate when the spring is actuated.

Abstract: Electronic stroke indicators have sensor structures which are incorporated into a stone shield for a brake actuator. The incorporation of the sensor into the stone shield protects the sensor and its associated wires and contacts from damage by the other components in the brake actuator. In particular, the spring is typically maintained out of contact with any of the electric portions of the electronic stroke indicator, thus prolonging the life of the electronic stroke indicator. In further features of this invention, a magnetic sensor may monitor the position of magnetic portions on a piston rod. Alternatively, a pair of electric contact switches may be serially contacted by a structure on the piston rod as the brake moves further out of stroke. The two electric contacts provided different signals to an operator in a vehicle cab such that signals of the level of out-of-stroke conditions are provided to the operator.

Abstract: The present invention provides a tamper-resistant fluid-operated brake actuator having a power spring housed within a head or cap which is attached to a flange case having one or more diaphragms or pistons responsive to changes of fluid pressure within the brake actuator chambers. In one embodiment, the head is attached to the flange case by a substantially continuous curvilinear annular metal retaining member which must be inelastically deformed or destroyed in order to remove the head from the flange case, thus rendering tampering more difficult. In another embodiment, the annular metal retaining member of the present invention is integral with the actuator head and which is metal-spun or the like onto the flange case.

Abstract: A shield for a brake actuator has a bore closely surrounding a piston rod which is welded to a yoke. The shield is formed with a plurality of slits that allow portions of the shield between the slits to bend radially outwardly and allow the yoke to move through the bore. Thus, the invention allows the use of a yoke which is welded to a piston rod, and also allows the use of a shield which closely surrounds the piston rod.

Abstract: A fluid-operated spring brake actuator has a funnel-shaped pressure plate which reduces the volume of fluid necessary to compress the spring and release the brake thereby providing a faster response time upon actuation of the brake.

Abstract: An improved hydraulic log splitter which includes a hydraulic reservoir formed integrally with a frame of the log splitter. Hydraulic fluid from the reservoir is supplied by a pump to a control valve. A fluid passage is open through the control valve to a hydraulic intensifier which includes a cylinder and a piston extendable from the cylinder. The piston pushes a log against a stationary splitting wedge. The piston is urged toward a retracted position by a return spring internal to the cylinder. When the control valve is in other than an "extend" position, hydraulic fluid supplied to the control valve is allowed to flow into a return conduit back to the reservoir. In this condition, the pressure the hydraulic fluid develops insufficient force to overcome the force exerted by the return spring, and the ram remains retracted.

Abstract: A short travel pneumatic cylinder device for transmitting a high force, comprising a cylinder housing having a cylindrical bore for guiding of the piston and of the piston rod, two pistons which upon generation of an overatmospheric pressure between the pistons will move in opposite direction, and further comprising a mechanical lever system with a housing cover. The first of the pistons is connected with the piston rod, and the second of the two pistons is arranged coaxially relative to the first piston, is hollow, and is movable coaxially relative to the piston rod. The first of the two pistons is connected to the lever system at the side of the interior of the cylinder opposite to the second of the two pistons. The pressure force exerted by the second piston is transmitted to the piston rod via the lever system in a direction opposite to the direction of movement of the second piston.

Abstract: An air-operated combination diaphragm spring brake has a tamper-resistant seal provided between a head (46) and a spring side of a flange case (18) which together form a spring chamber (16) housing a power spring (72). The head (46) has an annular rim (70), and the flange case has an annular flange (74) with a diaphragm (48) sandwiched therebetween. An annular lip (76) on annular rim (70) extends over the annular flange (74). A snap ring (82) is engaged by opposing annular grooves (80), (78) on the outside of the annular flange (74) and inside of the annular lip (76), respectively, to form the tamper-resistant seal.

Abstract: A spring brake actuator, formed by a housing having an elastomeric diaphragm dividing the interior into two chambers, comprises a pressure plate adjacent the diaphragm in one of the chambers with a large force compression spring between the pressure plate and the housing. A hollow actuator rod is mounted within the chamber for reciprocal movement with the diaphragm and the pressure plate and receives a permanently installed caging tool extending through a housing aperture, a pressure plate aperture and into the hollow actuator rod. The pressure plate includes a bearing in the pressure plate aperture to facilitate reciprocal movement of the pressure plate over the caging tool.

Abstract: A dust guard is provided for a brake actuating mechanism comprising a housing having first and second end walls, an elastomeric diaphragm suspended within the housing, a brake actuating rod disposed within the housing for reciprocating movement relative to the housing and having a first end and a second end, the second end being directed towards the second end wall of the housing, and a spring disposed within the second chamber between the second end wall and the diaphragm. The dust guard comprises a resilient tubular barrier, attached at one to the second end wall, and extending inwardly axially to engage the actuating rod, or structure connected to the actuating rod, to isolate the second end of the actuating rod from the interior of the housing.

Abstract: An air-operated combination diaphragm spring brake has a tamper-resistant connection between a head (46) and a spring side of a flange case (18) which together form a spring chamber (16) housing a power spring (66). The head (46) has an annular rim (70), and the flange case has an annular flange (78) with a diaphragm (48) sandwiched therebetween. A plurality of tabs (102) on one flange rotate into L-shaped channels (94) to lock the head to the flange case with a bayonet style engagement. An alternative embodiment employs threads (112, 114) on the head and adapter flanges to seal the spring chamber. A further embodiment seals the head to a cast flange case using a threaded hoop 116 fitted over the flange case to engage the threads on the head flange.

Abstract: The present invention provides a tamper-resistant fluid-operated brake actuator having a power spring housed within a head or cap which is attached to a flange case having one or more diaphragms or pistons responsive to changes of fluid pressure within the brake actuator chambers. In one embodiment, the head is attached to the flange case by a substantially continuous curvilinear annular metal retaining member which must be inelastically deformed or destroyed in order to remove the head from the flange case, thus rendering tampering more difficult. In another embodiment, the annular metal retaining member of the present invention is integral with the actuator head and which is metal-spun or the like onto the flange case.

Abstract: Disclosed is an improved spring brake assembly, and a method for making same, which is particularly resistant to unauthorized disassembly and its consequent hazards. A diaphragm is locked between two opposing portions of a housing. The two opposing portions of the housing are both made of steel and are welded rather than clamped to one another. The weld is performed in such a way that the diaphragm is not burnt or otherwise damaged by the welding process. The opposing portions are configured as a cylindrical coupling between a male member having an inwardly extending lip, and a female member preferably having an inner circumferential ledge, which cooperate to trap the periphery of the diaphragm at an end of the coupling remote from the weld.

Abstract: The present invention provides a tamper-resistant fluid-operated brake actuator having a power spring housed within a head or cap which is attached to a flange case having one or more diaphragms or pistons responsive to changes of fluid pressure within the brake actuator chambers. In one embodiment, the head is attached to the flange case by a substantially continuous curvilinear annular metal retaining member which must be inelastically deformed or destroyed in order to remove the head from the flange case, thus rendering tampering more difficult. In another embodiment, the annular metal retaining member of the present invention is integral with the actuator head and which is metal-spun or the like onto the flange case.

Abstract: The present invention provides a tamper-resistant fluid-operated brake actuator having a power spring housed within a head or cap which is attached to a flange case having one or more diaphragms or pistons responsive to changes of fluid pressure within the brake actuator chambers. In one embodiment, the head is attached to the flange case by a substantially continuous curvilinear annular metal retaining member which must be inelastically deformed or destroyed in order to remove the head from the flange case, thus rendering tampering more difficult. In another embodiment, the annular metal retaining member of the present invention is integral with the actuator head and which is metal-spun or the like onto the flange case.

Abstract: An air-operated combination diaphragm spring brake has a tamper-resistant clamp provided between a head (46) and a spring side of a flange case (18) which together form a spring chamber (16) housing a power spring (72). The head (46) has an annular rim (70), and the flange case has an annular flange (74) with a diaphragm (48) sandwiched therebetween in an interface (76). An annular retaining member (78) has a lip (86) which tightly captures a step (80) on the annular rim as the annular retaining member (78) is drawn over the interface (76) to form the tamper-resistant clamp.

Abstract: A dual master cylinder (10) for the braking system of a motor vehicle comprising a bore (18), a primary portion and a secondary portion (14), in which the secondary piston (44) of the secondary portion comprises an outer piston (65) slidable in the bore, and a central piston (78), the central piston including a main body (86) slidable in the bore and a secondary body (92) slidable in a piston bore (64) in the outer piston, the piston bore having a shoulder (72) engageable with a first abutment face (98) on the central piston to define a check valve (62), the piston bore providing a fluid passage (96,68) between the high pressure chamber (56) and the low pressure chamber (48) of the secondary portion, the check valve allowing hydraulic fluid to flow through the fluid passage during a rest mode or a release mode of the dual master cylinder, but preventing such flow during an apply mode.

Abstract: A brake actuating mechanism comprises a housing formed of facing shells with an elastomeric diaphragm suspended between them. A centrally disposed opening in the housing permits an actuating rod disposed within the housing to reciprocate through the opening. The diaphragm also has a centrally disposed opening. A pressure plate having a tubular section engages one side of the diaphragm. A spring is disposed between the pressure plate and the housing. The actuating rod extends through the opening in the diaphragm and is press-fit into the tubular section thereby simultaneously compressing the edge of the opening against the tubular section to form an airtight seal.

Abstract: The present invention provides a tamper-resistant fluid-operated brake actuator having a power spring housed within a head or cap which is attached to a flange case having one or more diaphragms or pistons responsive to changes of fluid pressure within the brake actuator chambers. In one embodiment, the head is attached to the flange case by a substantially continuous curvilinear annular metal retaining member which must be inelastically deformed or destroyed in order to remove the head from the flange case, thus rendering tampering more difficult. In another embodiment, the annular metal retaining member of the present invention is integral with the actuator head and which is metal-spun or the like onto the flange case.

Abstract: An air-operated diaphragm spring brake (10) is provided with a mounting means (16) which permits adjustment of the position of the pneumatic ports (30, 32) on the brake with respect to the vehicle. The mounting means (16) comprises a plate (84) mounted to an end section (88) of a housing (82) overlying a central aperture (90). A pair of threaded mounting studs (96) are fixedly secured to the plate (84) for mounting the plate to the vehicle.

Abstract: The present invention includes a three position actuator which is used to position the gear range control lever on a two speed transfer case. Three positions are required to achieve HIGH, LOW and NEUTRAL. Two individual air chambers may be selectively charged with compressed air to move two pistons along a common actuator rod to achieve linear translation of the control lever to selectively position the transfer case in HIGH, NEUTRAL or LOW range. The transfer case is shifted from LOW to NEUTRAL to HIGH by releasing the charge of compressed air thereby permitting the return spring to shift the control lever to HIGH gear range. Thus, in the event of failure of the system supplying the compressed air, the actuator will return the transfer case to HIGH gear range which provides an appropriate gear range selection for limp home mode.

Abstract: A linear actuator with a pair of in-line piston-cylinder combinations, separated by a partition. The combinations are supplied from a common source of fluid under pressure through a single inlet port. A guide pin prevents the uppermost piston from cooking, and serves as an upper limit stop. The pistons are biased into abutment with one another.

Abstract: An improvement in a conventional air-operated diaphragm spring brake is provided by a guide (100) being disposed in registry with an aperture (26) in a service brake housing (16). A push-rod (10) extends from a diaphragm (58) within the housing (12) through the bushing (102) to pivotably connect to a slack adjuster (6). The bushing (102) serves to maintain the push-rod (10) at a preselected angle relative to the slack adjuster (6) when the push-rod is in the inoperative position.

Abstract: A dual function brake and manual drive actuating system for selectively holding a rotatable member of a drive train and manually driving the drive train. A support structure is provided, with a brake operatively associated between the support structure and the rotatable member for holding the member against rotation. A common release member is operatively associated with the brake. A fluid retracting mechanism operates against the common release member to selectively hold the brake in disengaged condition. A manual retracting mechanism also operates against the common release member to selectively hold the brake in disengaged condition. A manual drive is incorporated in the manual retracting mechanism for manually rotating the rotatable member when in the disengaged condtion.

Abstract: The present invention provides a tamper-resistant fluid-operated brake actuator having a power spring housed within a head or cap which is attached to a flange case having one or more diaphragms or pistons responsive to changes of fluid pressure within the brake actuator chambers. In one embodiment, the head is attached to the flange case by a substantially continuous curvilinear annular metal retaining member which must be inelastically deformed or destroyed in order to remove the head from the flange case, thus rendering tampering more difficult. In another embodiment, the annular metal retaining member of the present invention is integral with the actuator head and which is metal-spun or the like onto the flange case.

Abstract: A first visual indicium (44) and a second visual indicium (50) are provided on a push rod (10) in an air operated diaphragm spring brake. The push rod (10) is mounted for reciprocal movement between an operative position and an inoperative position through an opening (26) in a service brake housing (16). The first indicium (44) comprises a discontinuity (45) in the surface of the push rod (10) having a leading edge (46) and grooves (48). The first indicium is positioned on the push rod such that the leading edge (46) will be exterior to the service chamber (12) only when the push rod is in the operative position and the brakes are substantially out of adjustment. The second visual indicium (50) comprises a second discontinuity formed of at least a leading edge (52) and a trailing edge (54). The second visual indicium (50) is positioned on the push rod whereby the trailing edge (54) will normally be exterior of the service chamber 12 adjacent the opening (26) when the push rod is in the inoperative position.

Abstract: A spring force actuator comprising a housing, an output member axially moveable in the housing, a spring captive between the member and the end wall of the housing. The actuator further comprises an axially located screw-threaded wind-off element operable to apply an opposing force to the spring between the output member and the end wall. The wind-off element is threadedly cooperable with a nut which is non-rotationally captive in an externally accessible recess of the end wall.

Abstract: Service/emergency brake actuator mechanism for use with the air brake system of a wheeled vehicle. A plurality of breather holes or openings are provided in the housing section of the emergency brake actuator chamber that houses the emergency actuator spring to maintain the chamber at atmospheric pressure. The openings are arranged such that regardless of the orientation of the brake actuator mounted in the wheeled vehicle, one of those openings will be located in the upper hemisphere of the chamber housing and another opening will be located in the lower hemisphere of the chamber housing. A flow resistant plug member, adapted to fit into any of the openings, is provided to seal whichever opening is oriented in the upper hemisphere of the chamber housing. This arrangement minimizes the amount of dust and dirt particles that enter the chamber and, thus, keeps the chamber free of contamination that could hinder actuator performance.

Abstract: The present invention teaches a brake cylinder which is formed by a cylindrical housing and a cylinder base. The cylindrical housing and cylinder base are joined together by a bayonet connection and form a pressure chamber. The bayonet connection is designed pressure-tight, and it is located on the pressurized-side of a circular sealing element which seals off the cylinder base from the cylinder housing. The bayonet connection is thereby protected from the entry of detrimental environmental influences, especially dirt and moisture, and it can still be easily disassembled at all times.

Abstract: An air-operated spring brake of the type wherein a spring-operated brake actuator is in tandem with an air-operated service brake actuator has a spring diaphragm which separates a spring housing into a fluid pressure chamber and a spring chamber. A spring in the spring chamber bears against a pressure plate to bias the diaphragm longitudinally in the spring housing in a brake-applying direction upon a decrease in pressure in the fluid pressure chamber. The diaphragm is movable generally longitudinally in the other direction to compress the spring in the presence of pressure in the fluid chamber to allow operation of the service brake actuator independently of the spring-operated actuator. A push plate, mounted to a push member, moves reciprocally with the diaphragm in the fluid pressure chamber in abutting relationship to the spring diaphragm.

Abstract: An improved spring brake construction is formed by a pair of concave metal housng portions having peripheral lips. Once the internal components of the spring brake are assembled within the housing portions, the lip of one housing portion is spun over the lip of the other housing portion to capture and grip it, thereby permanently sealing the housing portions together. The push rod and coil spring within the spring brake are maintained in axial alignment by a central indentation in one of the housing portions that extends coaxially within the coil spring, and by the construction of the spring diaphragm with a central axial protrusion which extends into a central opening in a spring plate on the side of the diaphragm facing the coil spring. On the opposite side of the diaphragm a push rod seat is laterally restrained from movement relative to the diaphragm.

Abstract: An integrated manual brake device on a brake actuation unit, particularly for rail vehicles, and it includes a hydraulic or pneumatic cylinder. The brake actuation unit contains a linkage setter including two parts displaceable relative to each other in a telescopic fashion. One of the parts is formed as a threaded spindle and the other tubular part is firmly connected with a nut which is screwed on the spindle with a nonselflocking thread. A stop is provided on the tubular part fixed in an axial direction but easily turnable. An actuating spring is clamped between the piston and the output part.

Abstract: A sensing means is provided to indicate an operating condition of a spring brake cylinder assembly in which such operating condition may be one of a brake applied and a brake release position. The sensing means engages a clutch control mechanism which includes means to engage the sensing means at different locations to make a determination of such operating condition.

Abstract: A gas cylinder valve for high pressure gas cylinders includes a pneumatic actuator with tandem pistons which are operated by normal industry "house" pneumatic pressures to overcome the large closing bias force generated by a set of disc springs so that the valve opening spring can lift the valve stem from its seat. A floating pressure plate which seats against an annular internal shoulder in the actuator housing prevents pneumatic pressure applied to the upper piston from acting on the back of the lower piston. Pneumatic pressure from a common source is applied to both pistons through an axial hole in a piston rod integral with one piston and bearing against the other piston. The actuator is easily assembled by merely inserting the lower piston, the pressure plate, the upper piston and the disc springs into the open end of a cup-shaped housing, and securing them in place with a preload on the springs by screwing on a housing cover.

Abstract: A spring brake actuator for a rail vehicle brake unit, comprising a cylinder and a rod shaped member. The actuator includes a cylinder-shaped housing, a piston with a piston rod and a spring intended to act in a brake applying direction.In order to obtain a truly modular system the actuator, as an integrated and self-contained unit, is arranged on the rod-shaped member of the brake unit. Its housing is attached to the brake unit cylinder. The actuator piston rod is tubular and slidable on the rod-shaped member.

Abstract: A hydraulic brake actuator including a hydraulic parking brake that can be applied by mechanically locking up either a normal service brake application or a hand pump operated brake application. The lock-up mechanism includes a friction collar that surrounds the piston push rod and a hand pump actuated locking member that surrounds the friction collar. The friction collar and locking member have complementary conical surfaces that are engageable when hydraulic hand pump pressure is applied to a piston face of the locking member to wedge the friction member into pressure engagement with the piston push rod, as a means of locking up the push rod to obtain a parking brake. The locking member also includes a plurality of spring-like fingers that project axially from the periphery of the locking member and are provided with latching tabs adapted to enter a recess in the body to prevent return-movement of the locking member when the hydraulic hand pump operation is terminated.

Abstract: Disclosed is a spring brake cylinder for use on motor vehicles. The cylinder is actuated to a release position in response to fluid pressure. The cylinder includes a spring actuator inserted between the brake cylinder base and a spring brake piston. A tensioning device is provided which mechanically acts upon the spring brake piston and facilitates adjustment of the distance between the spring brake piston and the cylinder base. The spring brake piston and the spring actuator can be assembled into a pretensioned unit outside the spring brake cylinder.

Abstract: A mechanical release arrangement for a fluid-pressure-operated braking cylinder having an emergency brake/parking brake feature includes a cylinder housing having formed therein a brake actuation portion, an emergency portion, an intermediate lever portion, and a coaxially-disposed brake-release arrangement interacting therewith. An actuator piston is movable within one pressure chamber and has a hollow rod portion extending therefrom on which the lever arrangement is secured. An emergency piston is retracted to a release position against the force of a spring arrangement by fluid pressure communicated to an emergency chamber. An extension sleeve extends from the emergency piston and has a first toothed portion formed at one end. A release rod extends through the extension sleeve and has a second toothed portion formed near a reduced diameter end.

Abstract: An anvil for our ultrasonic textile slitting apparatus comprises an elongated, flat, substantially rectangular, housing in which two pistons are disposed for motion relative to one another along the longitudinal axis of the housing. A first piston, responsive to fluid pressure, is urged against the force exerted by springs into motion toward the second piston for causing the second piston, which is provided with a slitting implement, to be urged toward contact with the output surface of an ultrasonic horn. Further, springs are interposed between the first and the second piston for urging the pistons apart, but becoming compressed responsive to such fluid pressure. The combination of fluid pressure and springs causes the slitting implement to be kept in continuous contact with the horn despite the very high acceleration forces manifest at the horn output surface. In addition, the springs provide vibratory isolation from the vibratory energy of the horn.

Abstract: A gas pressure actuator for effecting the reciprocation of the stem of a valve subject to high-pressure loading comprises a tubular housing secured to the valve bonnet and defining a main cylinder chamber connected in axially series relationship with an auxiliary piston chamber which, in turn, communicates with a secondary fluid pressure chamber containing a compressible spring. A rod-like actuator is slidably and sealably mounted within the actuator housing and carries a main piston which cooperates with the main cylinder chamber in sliding and sealable relationship. The auxiliary piston chamber slidably and sealably mounts an auxiliary piston which is movable independently of the main piston. The actuating movement of the main piston produced by the introduction of gas pressure into the main cylinder produces an axial movement of the actuating rod and a compression of the spring. The spring-containing secondary chamber defined by the actuator housing is filled with a virtually non-compressible fluid.

Abstract: A hydraulic servo device with a built-in accumulator, comprising a servo piston fit in a servo cylinder and connected via a stem to a band brake, an accumulator piston having a large diameter outer diameter portion and a small diameter outer diameter portion fit in the servo cylinder at two inner diameter portions thereof having different diameters and an inner diameter portion fit around a small diameter outer diameter portion of the servo piston, and an accumulator piston spring biasing the accumulator piston toward the servo piston.

Abstract: A safety restraint limiting the separation of brake actuator housings containing powerful compression springs. The restraint consists of a sheet metal body having a notch receiving the housing flanges, the notch being of sufficient dimension to permit partial separation of the housing flanges upon release of the flange clamp band, and the flange and restraint include engaging complementary surfaces which produce an inward force on the restraint when the restraint is subjected to axial spring forces thereby retaining the restraint notch in alignment with the housing flanges to limit axial separation thereof.

Abstract: A fluid pressure actuated motor assembly comprising a first fluid pressure actuated motor including a first reciprocating piston driven by a pressure differential across the first reciprocating piston, and a second fluid pressure actuated motor in communication with the first fluid pressure actuated motor and including a second reciprocating piston driven by the pressure differential across the first reciprocating piston.

Abstract: A method and apparatus are disclosed for assembling a protective boot in an air brake actuator. A mounting tube extends into the nonpressurized air chamber of the actuator and is formed with a groove in an outer peripheral surface. The end of the boot serves as a sleeve which is slipped over the end of the tube. A retainer ring, preferably carried by the boot, is forced downwardly to compress portions of the boot into the tube groove to thereby secure the boot in place.

Abstract: A pair of axially aligned and nested pistons are mounted in a pressure sealed arrangement within the bore of a pressure housing. A primary piston is moved in response to increasing pressure to provide an actuating output force while a secondary piston simultaneously moves to overcome a reverse bias on it by a tension spring and adds to the actuating force by engaging the primary piston only when the pressure exceeds a specific higher threshold. The primary and secondary pistons thereafter operate in conjunction under the influence of high pressure to provide the output actuating force.

Abstract: A spring-applied, air-released parking/emergency brake is combined with an air-actuated service brake through a friction clutch between the parking/emergency brake piston and a first nut member that is threaded onto a screw rod of the service piston. The screw rod and service piston are connected through another friction clutch. The screw rod is provided with a second nut member that is integral with a thrust rod to which the brake rigging is connected. A friction lock slack adjuster arrangement limits retraction of the thrust rod during brake release in accordance with the desired brake shoe clearance to be maintained. When the thrust rod movement is inhibited by the slack adjuster, the service piston clutch becomes disengaged to permit rotation of the screw rod during the release stroke of the service piston corresponding to overtravel due to shoe wear. Brake shoe clearance is thus maintained constant.

Abstract: The invention pertains to vehicle brake actuators of the expansible motor type wherein the actuator includes a cylinder having a piston and piston rod assembly reciprocal therein, a helical spring biases the piston in a braking direction, and a pressurized medium, such as hydraulic fluid, forces the piston in a spring compressing direction. The unique features include a piston drawn from sheet metal wherein the piston rod is pressed thereinto, and the piston seals are retained in position by a wire ring having an interference fit with the piston. Additionally, novelty resides in the use of a retainer formed of wire or of stamped construction having protuberances defined thereon for retaining the cylinder end cap upon the cylinder in a manner to permit ease and safety of assembly, and uniform force distribution.

Abstract: An air brake includes a service brake chamber which actuates a push rod. A collet brake chamber is partially defined by a collet brake diaphragm. A locking collet is mounted to the collet brake diaphragm and includes a bore through which the push rod passes. A collet brake spring biasas the collet into a tapered collet hole to clamp the collet onto the push rod to prevent the movement of the push rod toward the brake off position. Application of pressure to the collet brake chamber overcomes the force of the collet brake spring and moves the collet away from the tapered collet hole to allow the push rod to move freely. The collet can be moved towards and locked against the collet brake spring to prevent the collet from engaging the push rod. This allows the user to effectively deactuate the collet brake feature when desired, such as to mechanically release the push rod from the collet when the vehicle is stationary.

Abstract: An air brake includes a service brake chamber which actuates a push rod. A collet brake chamber is partially defined by a collet brake diaphragm. A locking collet is mounted to the collet brake diaphragm and includes a bore through which the push rod passes. A collet brake spring biases the collet into a tapered collet hole to clamp the collet onto the push rod to prevent the movement of the push rod toward the brake off position. Application of pressure to the collet brake chamber overcomes the force of the collet brake spring and moves the collet away from the tapered collet hole to allow the push rod to move freely. Excessive force on brake drums, caused by cooling and contracting brake drums while parked, can be reduced by permitting the collet and push rod therewith to deflect when such excessive force occurs.