Abstract: In a brake system of a vehicle adapted to be operated automatically, the brake system includes a forecasting mechanism for forecasting a need of automatic braking, and a pump to provide a source of a pressurized working fluid for the automatic braking is started when a need of an automatic braking is forecast. By such a need forecast starting of the pump, the brake system can automatically apply an effective braking to a vehicle wheel or wheels, with no accumulator for storing the pressurized working fluid. The pump need forecasting may depend upon an estimation of a turn behavior of the vehicle and/or a detection of an obstacle in front of the vehicle.

Abstract: A hydraulic brake slack adjuster disposed between a brake valve and an actuator of a brake mechanism has a first piston exposed to pressurized brake fluid from the valve and a second larger piston connected to the first piston for outputting brake fluid to the brake actuator with the fluid output to the actuator being greater than the volume of input fluid from the valve. This permits a smaller pump to be used while maintaining sufficient brake operation speed.

Abstract: A cutoff valve for pistons of hydraulic self-adjusting devices, comprising an essentially cylindrical through element (18), attached axially to the internal end of the rod (3) of the device (1), and a cutoff element (19), also essentially cylindrical, arranged coaxially with the rod (3) on which it slides with a tight fit. The through element (18) has through holes (23) through which the liquid fluid (F) contained within the main body (2) of the device (1) can flow. The cutoff element (19) has a cutoff joint (29), which can block the holes (23) of the through element (18), and a peripheral thickening (30) provided with a sealing joint or ring (33) and a number of channels (31) through which the liquid fluid (F) can flow freely. The cutoff valve can be used in the car industry.

Abstract: A brake system for use with a rotatable mechanical load. The brake system includes a brake apparatus operative to selectively apply a braking torque to the load. The braking mechanism within the brake apparatus preferably includes a plurality of brake plates interleaved to form a brake plate assembly. The braking mechanism may be biased to normally engage the brake plates so that a predetermined braking torque is applied. In this case, braking torque is varied by controllably releasing engagement of the brake plates. The braking mechanism is preferably designed to apply full braking torque if wear of the brake plates exceeds a predetermined threshold. Heat generated during operation of the braking mechanism is preferably removed by coolant fluid. The coolant fluid may be supplied by a coolant pump driven by operative rotation of a pump drive shaft. A properly-sized flywheel is preferably coupled between the pump drive shaft and the device driving the pump drive shaft.

Abstract: The present invention provides a hydraulic brake piston adjuster assembly (10) that includes a first or outer piston (30) housing and a second inner piston (40). The first piston (30) has a first piston end (31) received within a housing bore (16) and the end (31) extends axially to include an inlet (32) having a relief valve mechanism (34). The second piston (40)includes an axially inner second piston end (42) received within the bore (36) of the first piston (30) and extends axially to encompass the inlet (32) of the first piston (30) and so that the piston ends (31, 42) define therebetween an inner piston chamber (50). A first piston second end abuts a running clearance adjustment mechanism (59) comprising an axially displaceable collar member (60).

Abstract: A clutch or brake unit is described with an automatic wear adjustment mechanism.Clutches and brakes operate by the engagement of friction members (4,6) which experience wear in use requiring a larger stroke of the unit to effect engagement. This results in delayed clutch or brake operation which can be a serious disadvantage where prompt action is required. Conventionally this wear has been compensated by replacement of the worn friction members or by manual adjustment of them resulting in temporary disablement of the unit and requiring service personnel time.In the inventive unit, friction members (4,6) are mounted between pressure members (10,2) and an actuator (12) operates against a backing member (15) to effect clutch or brake actuation and de-activation by movement of the friction members towards and away from each other, and the position of at least one of the pressure members is adjusted automatically in response to wear of the friction members.

Abstract: A self-adjusting actuator is disclosed that utilizes a hydraulic system for adding necessary brake fluid to move brake actuating pistons sufficiently to bring brake linings into contact with a brake drum, regardless of how much wear has taken place on the linings. The self-adjusting actuator also incorporates a threaded plunger sleeve, interposed between an actuating piston and the brake shoes, to limit the retaction of the shoes away from the brake drum so as to maintain the proper running clearance after adjustment. The system incorporates a compensator piston having one face acting on incompressible brake fluid filling the chamber between the compensator piston, the actuating piston and a surrounding housing. An opposite face of the compensator is acted upon by pressurized brake fluid when the operator of the vehicle depresses the brake pedal.

Abstract: A hydraulic power unit for a hydropneumatic brake actuator having a power piston comprising a force piston formed with a bore therein and a take-up piston operative in the force piston bore for movement relative thereto during a brake application. This relative movement is controlled by a check valve device carried with the force piston to establish or interrupt fluid pressure communication between the respective pistons and establishes a positive clearance between a brake shoe and wheel tread, for example, during a subsequent brake release.

Abstract: An improved self-compensating device for a drum brake of the type including a first member and a second member which together define a hydraulic chamber in a wheel cylinder, said first and second members being slidably but non-rotatably arranged relative to one another so that brake shoes are actuated by displacement of the members away from one another which is initiated by hydraulic pressure introduced into the hydraulic chamber.

Abstract: The brake motor comprises an inserted piston (26) slideably mounted in a passage (24) formed in the front wall (4) of the brake piston (1) which has, near the other end (31) of the inserted piston (26), a counter-bearing surface (34) facing inward, thus enabling the engagement of an actuating tool (0) to exert, via the inserted piston (26), an axial thrust on the rotating member (16) of the automatic adjustment device of the brake motor and, at the same tine, an axial load in the opposite direction on the brake piston (1) enabling the friction clutch (18, 19) to release between the brake piston (1) and the rotating member (16), after which an axial translation (F) of the assembly enables the resetting of the automatic adjustment device of the brake motor.

Abstract: The compensator comprises at least an element coupled to a clutch mechanism and an element coupled to a declutching control lever. According to the invention, one of the elements is formed by a cylindrical body (17) filled with a hydraulic fluid, in which is axially slidable a sleeve (20), and the other of the elements is constituted by a piston (21) axially slidable inside the sleeve (20).

Abstract: The present invention provides a brake actuation and adjuster system comprising means for applying brake actuation pressure both to a brake actuator member and to a pump. The pump is arranged to pump pressure fluid to an adjuster control valve and an adjuster actuator, and the brake actuator member is arranged to be moved by said brake actuation pressure to then open the adjuster control valve against the pressure of the pressure fluid after the brake actuator has moved to a predetermined release position. Thus, in one embodiment, brake actuation pressure primes the pump causing the pump to force pressure fluid to the adjuster actuator. If adjustment is necessary, it is effected until the adjuster control valve is opened to release the pressure fluid. Thus a simple, independent adjuster arrangement is provided which does not affect available brake performance.

Abstract: Spring-loaded cylinder with a tension piston (7) which can be pressurized by a pressure medium. Between the tension piston (7) and a piston rod (3) movable thereby, a cylinder-piston arrangement (19, 20, 21) is installed, whose cylinder chamber (21) can be pressurized from the pressurization chamber (10) of the tension piston (7) via a sealing ring (18), constituting a reflux valve. A first axial friction coupling (17, 18) is provided between the tension piston (7) and the piston rod (3) and a second friction coupling (13, 14) between a housing section (1) and the piston rod (3). The second friction coupling (13, 14) has a buffer clearance A, corresponding to the nominal application stroke. The friction force of the first friction coupling (17, 16) is greater than the expansion force of the cylinder-piston arrangement (19, 20, 21), and the friction force of the second friction coupling (13, 14) is greater than the friction force of the first friction coupling (17, 16) reduced by the expansion force.

Abstract: A disk brake actuator having a hydraulic slack-adjusting arrangement for maintaining a positive clearance between a brake shoe and a brake disk, includes a cylinder housing having disposed therein a brake-applying spring section, a hydraulic-operated release section, and an actuator piston spindle arrangement operably-connected to the spring section by way of a clutch arrangement. A flange, formed on the actuator piston, acts as a plunger during a brake application and draws a first amount of hydraulic fluid into a first storage area, such first amount corresponding in volumn to the clearance between the brake disk and brake shoe when a nonworn brake shoe is first used. Upon release of the brake, the actuator piston forces the hydraulic fluid back into a second storage area wherein is included a shuttle member movable with a shuttle chamber. Additional hydraulic fluid is drawn from a reservoir when actuator piston movement, beyond the original clearance value, occurs as a result of brake shoe wear.

Abstract: A fluid pressure actuated piston (78) is slidably carried in a fluid pressure actuated cylinder (50) which, in turn, is slidably carried in a fixed carrier or casing (21). Movement of the cylinder (50) is resisted by a breakable or displaceable coupler (90, 94, 184, 185) which engages the cylinder (50). Fluid pressure acting upon the cylinder (50) and piston (78) causes the coupler (90, 94, 184, 185) to break or be displaced and release the cylinder (50) for axial movement in the direction of movement of the pressure responsive piston (78).

Abstract: A combination air brake cylinder and hydraulic slack adjuster for a railroad car brake system includes an air operated piston positioned within a housing. There is an air port in the housing in communication with the air piston and there is a return spring in the housing operable upon the air piston. The housing includes a fluid outlet port and a fluid piston and valve arrangement within the housing connected to the air piston and responsive to brake application movement thereof to supply a brake shoe application fluid pressure at said outlet. A fluid reservoir is associated wtih the fluid piston and valve arrangement and has check valve controlled connecting passages thereto for adjusting slack in the brake rigging during brake application functions.

Abstract: A two-stage, hydro-pneumatic actuator suitable for use as a railway vehicle brake. The hydraulic cylinder comprises a large diameter bore in which a low- and a high-pressure piston operate jointly during a first stage of operation to effect a high volumetric displacement of hydraulic fluid via a small diameter bore in order to take up the clearance between the brake shoes and wheel. As the brake shoes contact the wheel, the high-pressure piston enters the small bore to interrupt further displacement of hydraulic fluid from the large bore. The force of the high-pressure piston alone during this second stage of operation produces the required brake forces with a high multiplication factor. Make-up fluid is drawn into a chamber on the backside of the low-pressure piston during a brake application stroke an amount corresponding to the over-travel of the high-pressure piston and is subsequently discharged into the hydraulic cylinder during retraction of the brakes to compensate for brake shoe wear.

Abstract: In brakes in which a friction member is urged into engagement with a rotatable braking member by a fluid-pressure operated actuator, for example internal shoe-drum brakes, the actuator and an adjuster for adjusting brake clearances are located between different pairs of shoe-ends.If the adjuster is automatic, it is difficult to transfer signals at the actuator that adjustment is required to the adjuster with sufficient energy to operate it, without affecting the operation of the actuator. Thus the adjuster is operated by a supply of pressure fluid controlled by a valve assembly which is operative to supply fluid to the adjuster when relative movement between parts of the actuator exceeds a predetermined value. The adjuster is operated by a slave unit.The valve assembly may comprise a valve operated by rotation of a shaft for applying the brake, or two valves embodied in the actuator itself.

Abstract: A hydro-pneumatic brake actuator having a friction element positionable by the power piston during the brake application stroke through a lost-motion connection therewith to establish a stop to limit movement of the power piston during a brake release and thereby provide a predetermined brake shoe clearance. In an alternate embodiment, a leaf spring is carried by the friction element to provide a cushioned stop for the power piston to prevent inadvertent displacement of the friction element, by reason of wheel out-of-roundness imparting a "kick-back" force on the power piston.

Abstract: A hydro-pneumatic brake actuator arranged with a slack adjuster piston and one-way check valve device in the hydraulic path between a hydro-pneumatic actuator and a power piston, to which a friction brake element is connected for engagement with a vehicle wheel tread or brake disc during a brake application. During a brake release, the one-way check valve closes a passage through the slack adjuster piston to cause the piston to shift from its one extreme position to the other extreme position with the fluid flow, as the hydro-pneumatic actuator is moved from its application position to its release position. This in turn draws hydraulic fluid from the power piston chamber into a clearance volume created by shifting of the slack adjuster piston, and accordingly forces the power piston to retract a predetermined distance corresponding to the capacity of the clearance volume and the effective area of the power piston, thereby maintaining a constant brake shoe clearance during brake release.

Abstract: A disc brake assembly includes a caliper movable relative to a rotor for the purpose of urging a pair of friction elements into engagement with the rotor. A housing of the caliper defines a stepped bore for receiving a piston which cooperates with the housing to form a pressure chamber within the stepped bore. A plate within the pressure chamber separate the pressure chamber into a pair of cavities and a valve assembly controls communication of fluid pressure to one of the pair of cavities and to the other cavity. During initial fluid pressure build-up in the caliper, the valve assembly remains in a first position to communicate fluid pressure to one of the cavities so that the plate and piston advance to a braking position at a first rate of speed.

Abstract: In a hydraulic brake system the fluid slack is maintained at a predetermined volume by a flow control valve that is positioned between a fluid reservoir and a slack adjusting cylinder. The flow control valve closes the fluid path to the reservoir after a chamber in the cylinder fills with a predetermined amount of slack fluid. The flow control valve can be held open with a detent mechanism to permit servicing of the brake system. The detent is automatically released when the brakes are applied.

Abstract: In an automotive clutch having a clutch disc clamped between the flywheel and a movable pressure plate held by strong springs anchored on the rotating cover and lifted by action of a throw out bearing movable concentrically of the transmission input shaft to engage the release fingers which lift the pressure plate, and a clutch pedal in the operator's compartment of the vehicle, a linkage for moving the throw out bearing against the release fingers, the linkage including a length adjustable hydraulic fluid filled link and a valve thereon to bleed off a small quantity of the hydraulic fluid when the release fingers bear firmly against the throw out bearing while the linkage is in rest position to relieve pressure on the hydraulic fluid and allow the throw out bearing to move away from the release fingers.

Abstract: A hydraulically operated disk brake apparatus for a motor vehicle comprises a brake disk, a caliper-like brake housing disposed to straddle over the brake disk and having a pair of arms, and a pair of brake pad assemblies disposed in the brake housing in opposition to each other with the brake disk being interposed therebetween. The brake pad assemblies are movable toward and from the brake disk. A cylinder chamber is formed in one of the caliper arms and accommodates therein a first piston for pressing the adjacent brake pad assembly to the brake disk and a second piston positioned with a distance from the first piston. The second piston is operated by an externally provided actuator member to produce a hydraulic pressure in the cylinder chamber for moving the first piston and the associated brake pad assembly toward the brake disk. A reservoir for hydraulic fluid is formed in the brake housing to supply supplementary fluid into the cylinder chamber.

Abstract: A fluid pressure actuated piston is slidably carried in a fluid pressure actuated cylinder which, in turn, is slidably carried in a fixed carrier. Forward axial movement of the cylinder is restricted by a hydraulic pressure balance condition which is created by reducing the rearward surface area of the cylinder. The cylinder is maintained in a pressure balanced condition during the entire operation of the piston assembly. After the piston moves axially forward a predetermined distance, it engages the cylinder and urges the cyliner axially forward the same distance traveled by the piston. The piston's maximum axial movement is thereby extended by the distance the cylinder travels. The output force of the piston is substantially unaffected by the force imposed on the cylinder. Also, the cylinder does not provide any work force area.

Abstract: The hydraulic activators are provided with a relief valve which serves to permit communication between the disengaging cylinder chamber and the work cylinder chamber. The open position of the relief valve occurs when the release apparatus for the rotatable friction brake member is closed. The closed position of the relief valve occurs after the rotating brake is released. The relief valve can be mounted in the release apparatus of the working piston.

Abstract: A fluid pressure operable brake cylinder device including a self-adjusting portion for automatically compensating for brake pad wear and maintaining a constant clearance between the brake pad and the braking surface of a vehicle wheel in the released disposition of the brakes.

Abstract: A disc brake assembly including a self-contained actuator for urging a brake shoe into frictional engagement with a friction disc; the actuator including an actuated piston movably supported within a cylinder for moving the brake shoe into engagement with the friction disc, an actuating piston movably supported within the cylinder which is separated from the actuated piston by a fluid-filled chamber which defines a fluid link therebetween and a rotatable, threaded shaft member connected to the actuating piston for transmitting rotational motion to axial motion whereby rotation movement of the shaft member causes axial movement of the actuating piston which in turn causes axial movement of the actuated piston through the fluid link. In order to compensate for separation between the actuated and actuating pistons as a result of brake wear, the cylinder includes a fluid reservoir for supplying additional fluid to the fluid-filled chamber upon separation of these two members.

Abstract: An extensible cylinder slidably containing a fluid pressure actuated piston is provided with differential first and second area portions exposed to a piston actuating pressurized fluid and an opposing pressurized fluid which opposing fluid is pressurized by a fluid pressure amplifier or booster responsive to the piston actuating pressurized fluid to maintain a proportional relationship between the pressures of the piston actuating fluid and opposing fluid to thereby generate a force balance on the cylinder. A stop on the cylinder is engaged by the piston upon completion of the piston stroke in the cylinder causing the cylinder to advance with the piston to thereby extend the stroke of the piston. The volumetric requirement of the piston actuating pressurized fluid for a given displacement of the piston is constant regardless of the position of the extensible cylinder.

Abstract: A self-contained brake actuator assembly including a cylinder, an actuated piston within the cylinder, an actuating piston, a rotatable threaded shaft for translating rotational motion to axial motion operatively connected to the actuating piston, a fluid-filled chamber between the actuated and actuating pistons defining a fluid link therebetween whereby axial movement of the actuating piston causes axial movement of the actuated piston, wear take-up and anti-drag structure for permitting substantially free forward movement of the actuated piston in unison with the actuating piston and for limiting retraction of the actuated piston to a predetermined maximum distance, and a fluid supply contained within the cylinder for supplying additional fluid to the chamber in response to retraction of the actuating piston a distance greater than the predetermined maximum for the actuated piston to thereby accommodate the increase in volume of the chamber occasioned by the resultant separation of the pistons.

Abstract: The disclosure concerns a hydraulic slack adjuster useful in the brake circuits of railway as well as road vehicles, and improved brake circuits and apparatus particularly suited to the needs of railway rapid transit service. One type of circuit incorporates the slack adjuster in combination with a simple air-to-hydraulic booster and defines a portion of a service brake, and another type utilizes this apparatus in combination with a hand brake control unit and a double check valve and enables the brake cylinders to perform both service braking and hand braking functions.