Abstract: In a braking unit of the SAHR type comprising a braking pack with disks and counter-disks, a resilient system for compressing the pack with a braking load sufficient for parking braking, a first hydraulic system for exerting on the resilient system a contrary load sufficient to cancel out its effect, a second hydraulic system acting on the pack to compress it with a braking load sufficient for service braking, both hydraulic systems share a single piston acting on one side on the pack and on the other side on the resilient system.

Abstract: If cylinder bores formed in a caliper parallel to each other are communicated together through a pipe casted in the caliper, the pipe tends to come out of the caliper into a cylinder bore. A separate short pipe is provided to communicate the cylinder bores. The pipe has an engaging portion so as to extend in a diametric direction of the short pipe to prevent longitudinal shift of the short pipe. The engaging portions can be provided easily by forming a recess or a protrusion on the outer periphery of the pipe and casting the pipe in the caliper.

Abstract: The present invention relates generally to a hydraulic braking system for use in equipment such as cranes that rotate about a fixed base. The braking system described herein utilizes a twin piston hydraulically activated system wherein separate service and parking brake pistons are applied to opposite sides of a common brake pack. The two braking pistons may be independently actuated. The brake pack consists of interleaved rotor disks (friction disks) which are splined to a central rotating shaft and stationary (stator) disks which are secured against movement by interlocking them with the casing of the device. The brake pack is movable axially such that in operation an active parking brake piston presses against the brake pack which moves until it is supported on its reverse face by a passive service brake piston. Similarly, when the service brake is applied the brake pack moves and is supported on its opposite face by a passive parking brake piston.

Abstract: In a braking axle driven by a wheel of a trailer vehicle, wherein an axle-driven pumping mechnism is used to pressurize a volume of hydraulic fluid in response to a braking command, the fluid pressure activates a turbine which in turn drives a cooling fan aimed at a radiator used to dissipate the heat accumulating into the hydraulic fluid. The coaxially circular arrangement of the pumps, control valves and other components of the system yields a simple, efficient and sturdy mechanical structure that can withstand very high internal fluid pressure with a limited and controllable leakage rate.

Abstract: A method of cooling a brake fluid using a brake operating unit which comprises a first and a second flow channels connected to a cylinder of a brake element at one ends thereof comprises a step of setting the absolute value of a difference between the amount of brake fluid supplied to and that discharged from the cylinders in the first flow channel to apply and release brakes respectively equal to the absolute value of a difference between the amount of the brake fluid supplied to and that discharged from the cylinder in the second flow channel to apply and release the brakes respectively, so as to circulate the brake fluid in the cylinder using both of the first and second flow channels by repetition of applying and releasing the brakes.

Abstract: The present invention provides a hydraulic fluid tank assembly for a vehicle having a hydraulic brake cooling circuit and a hydraulic steering circuit. The hydraulic tank assembly includes a hydraulic tank that has a brake cooling section fluidically coupled to the hydraulic brake cooling circuit of a vehicle and a steering section fluidically coupled to the hydraulic steering circuit of a vehicle. The steering section further is fluidically coupled to the brake cooling section such that hydraulic fluid may flow between the brake cooling section and the steering section of the hydraulic tank. A barrier plate disposed in the tank separates the brake cooling section from the steering section. The barrier plate has a through hole that fluidically couples the brake cooling section with the steering section; and a hydraulic fluid strainer is disposed in the through hole of the barrier plate in order to strain hydraulic fluid that flows between the brake cooling section and the steering section.

Abstract: A device for cooling brake fluid in a brake operating unit which comprises first and second flow channels having respective one ends connected to a cylinder of a brake element. The brake fluid circulates in the cylinder using both of the first and second flow channels by repetition of applying and releasing the brakes. As a result, it is possible to provide a device for cooling a brake fluid, wherein vapor-lock can be presented with certainty, the brake element that is a drum brake or a disc brake is improved in safety and reliability, friction materials such as brake shoes or pads are restrained from rising in temperature and a fade phenomenon is also reduced so that a stable braking operation can be obtained.

Abstract: A drive unit for vehicles with an engine and a gearbox, and with a hydrodynamic retarder. The retarder is in constant drive connection with the engine. The unit includes a coolant circuit whose coolant is at the same time the working medium of the retarder, and the retarder can be utilized as a coolant pump. The retarder is arranged before the gearbox, and the retarder can be united with an engine brake to an overall brake unit (OBU). The overall brake unit is configured such that the retarder can in a braking operation engage sooner than the engine brake.

Abstract: Apparatus for automatically compensating or adjusting for the slack or added travel as frictional material on brake pads wears during repetitive brake applications. A stack of snap rings each having a gap in its periphery is collapsed or compressed and assembled onto the inside diameter of a wall of a hydraulic pressure applied cylinder portion. The wall inside diameter has a shoulder with a first diameter that holds the snap rings in their compressed condition. Contiguous to that section is a second wall section having a diameter larger than the first section such that as the cylinder is extended further during a braking action because of wearing of the brake pads, one of the snap rings is forced into the larger diameter area thus expanding it and preventing the wall portion of the cylinder from returning to its original position, thus maintaining the gap constant.

Abstract: A method and apparatus for estimating internal brake energy in a fluid cooled brake of the type used in large work machines from easily sensed machine operating parameters. The temperature of the coolant is sensed before and after it passes through the brake. The coolant flow rate through the brake is determined from one or more additional sensed parameters, for example engine speed. The sensed parameters are used in a thermodynamic model of the brake which generates estimates of internal brake temperature (TEIB) and the amount of power absorbed by the brake (BRKP). Signals representing TEIB and optionally BRKP are generated to provide indications of brake operation and/or health. The model is executed on a digital computer either on-board the vehicle or at a remote location.

Abstract: A brake assembly, for causing brake pads to brake a rotor having opposite sides, comprises first and second caliper sections, and piston chambers associated with the sections. Pistons are movable in the chambers to cause the pads to frictionally engage the opposite sides of the rotor. Structure interconnects the caliper sections; and there is porting in the structure to transmit fluid pressure to the chambers to cause the pistons to displace the pads to frictionally grip the rotor, for braking same.

Abstract: A brake assembly, having a plurality of co-operating rotating and non-rotating brake discs, includes a dump valve mechanism, including a spool valve. The spool valve is adapted to move between first and second positions to close and open fluid communications between a fluid supply passage and a fluid dump passage. Excess cooling fluid supplied to a brake assembly when the brakes are inactive causes "brake drag" which wastes power and decreases machine efficiency. By dumping the cooling fluid to a fluid dump passage when the brakes are inactive, the "brake drag" is reduced.

Abstract: In present day construction equipment, it is common practice to provide braking capability for each driven axle. The conduits that deliver the pressurized actuating fluid to the brake assemblies are normally mounted in close proximity to existing framework to protect them from contact with debris and other structure common to the environment in which a construction vehicle operates. In some of the more severe environments, this type of mounting does not afford the conduits adequate protection, and they have been known to suffer damage. The area most prone to damage in this situation is the area around the axle assembly where the conduits split to communicate the pressurized fluid to each brake assembly associated with each end of the axle. In the present invention, a fluid conduit assembly is provided that is mounted entirely within the internal cavity defined by the axle housing.

Abstract: A brake cooling system for applying a pre-cooling bath to the brake packs of a vehicle through a brake coolant valve having an actuating piston chamber. The brake cooling system is responsive not only to the application of operating pressure to the brake pedal but also to release of the throttle. To operate the brake cooling system in response to the throttle setting, the brake cooling system utilizes a cut-off valve having a transfer chamber. A signal feed conduit communicates between the transfer chamber and the actuating piston chamber in the brake coolant valve. A computerized control member provides pressurized control fluid to the actuating chamber of a modulator control valve. The pressure of the control fluid is established in response to the throttle setting. A hydraulic timer is provided to interrupt the entry of the signal pressure into the transfer chamber after a predetermined period of time.

Abstract: In a self-energizing disc brake of the spreading type the actuator mechanism incorporates a restrictor in the form of a circumferentially extending discontinuous oil-seal which co-operates with radial faces on the two pressure plates. A secondary, or elevated, reservoir for liquid is therefore defined between said pressure plates by said oil-seal. Liquid can escape from this reservoir in order to enhance the cooling of the braking surfaces, defined by engagement of rotatable friction discs with end faces of a housing, pressure plates and a planar non-rotatable disc. In the brake shown in FIG. 6 two annular members act as seals on the ends of the outermost friction discs.

Abstract: A liquid-cooled disc brake for use in a vehicle having a rotatable shaft, at least one rotor fitted to the outer peripheral surface of the shaft, in which the rotor is unrotatable but slightly axially movable with respect to the shaft, a caliper secured to the vehicle body, having a first wall, a second wall positioned opposite to the first wall and a third wall. The caliper is substantially U-shaped in section with its inner peripheral side opening to thereby surround the whole perimeter of the rotor. The second wall of the caliper is made hollow so that the cooling liquid circulates freely through the hollow portion of the second wall. The disc brake further includes means for thrusting against the rotor provided at an inner side of the first wall of the caliper. The thrust means is operated at the time when the brake is performed.

Abstract: A combined wheel/brake apparatus employing an electro-rheological fluid. The apparatus includes a wheel rotatably mounted on an axle and a first array of spaced, electrically conductive vanes extending in a first direction with the vanes non-rotatably held by the axle. The apparatus also includes a second array of spaced, electrically and thermally conductive vanes extending in a direction opposite the first direction, with the second and first arrays interdigitated but not contacting. An electro-rheological fluid is in the spaces between the vanes. At least some of the second vanes have a coolant passageway and the apparatus further includes a secondary coolant supply for these passageways. The coolant passageways are isolated from the electro-rheological fluid so that application of an electrical potential across the two array vanes causes an increase in the viscosity of the electro-rheological fluid to develop a braking force, with heat occasioned by the braking being transmitted to the secondary coolant.

Abstract: A hydraulically controlled disk brake of a motor vehicle having at least one hydraulically actuable brake piston that is arranged in a caliper and is guided in at least one cylinder. The brake has a duct which continuously serially connects the cylinders in each half of the caliper, this duct having separate inlet and outlet openings. A check valve for each inlet and outlet opening is respectively arranged in front of the first cylinder after the inlet opening and behind the last cylinder before the outlet opening with respect to flow direction.

Abstract: In a hydraulic dual-circuit brake system for motor vehicles, especially high-powered heavy passenger cars, in which the front wheel brakes combined in a front-axle brake circuit are exposed to higher thermal loads than the rearward brakes, brake fluid is conveyed by means of a feed pump to the outlet-pressure space for cooling the front wheel brakes following a braking phase. Circulated brake fluid flows from the master cylinder outlet pressure space assigned to the front-axle circuit, to the wheel brake cylinders, to an additional functional space of the primary piston in the master cylinder, and back to the supply vessel. The circulating fluid pump is controlled by a timing relay which is tripped by the brake-light switch and remains energized for a predetermined time interval to allow sufficient cooling by fluid circulation.

Abstract: A drum brake assembly is described to comprise a dual drum brake housing mounted to a vehicle wheel or shaft to be rotated therewith. The dual drum brake housing has two axially extending, concentric, radially spaced drum surfaces defining an annular channel between them. A torque member is fixed against rotation with the vehicle wheel and an expandable friction lining assembly is mounted to the torque member. The friction lining assembly is positioned within the annular channel and carries radially outward and radially inward facing friction linings. Upon expansion of the friction lining assembly each of the friction linings is moved into contact with the corresponding drum surface, thereby transferring braking force to the wheel.

Abstract: The present cooling system provides a limited flow rate to the clutches during disengagement and provides additional cooling flow to the clutches during partial engagement and controls the pressure level of the fluid from the source of cooling fluid by operation of a valve mechanism which is responsive to a control mechanism. Upon full engagement, the valve mechanism automatically reduces the volume of cooling fluid to the clutches and simultaneously reduces the pressure level of the cooling flow from the source of cooling fluid. This cooling system provides the needed volume of cooling fluid during partial engagement of the clutches and also reduces the volume of cooling fluid during disengagement to reduce drag forces while further reducing the volume of cooling fluid during full engagement to conserve horsepower.

Abstract: There is disclosed herein a brake unit of the oil shear type which is specifically designed for use in controlling the drawworks of drilling rigs or the like. The drawworks brake unit comprises an input shaft driven by the drawworks which operates to drive a gear pump for circulating high volumes of oil under pressure over interposed brake discs and plates and through adjacent restricted orifices during a first direction of rotation such as during lowering of the pipe stands so as to both cool and lubricate the discs and plates. During an opposite rotation of the input shaft, such as during raising of the pipe stands, an alternate flowpath is provided by-passing the restricted orifices so as to reduce the drag placed on the drawworks during raising of the pipe stands. During the first direction of rotation or lowering, the gear pump also operates to provide self-actuating overspeed safety protection as well.

Abstract: An automatic purge valve 110 for removing air and/or vapor from a fluid pressure operated brake system. The valve comprises a chamber 120 disposed in a brake assembly that includes a pair of opposed coaxially aligned valve seats 120b, 134b and a valve member 130 disposed in the chamber and engagable with either of the seats. The seat 134b communicates with a brake coolant system 58; the other valve seat 120b communicates with a piston retraction fluid chamber 90. The valve member is biased towards the one valve seat 120b by pressure in the coolant system and is driven toward the other valve seat 134b during brake actuation by fluid pressure in the piston retraction fluid chamber. Air and/or vapor is discharged from the retraction fluid circuit into the coolant circuit as the valve member travels from the seat 120b to the seat 134b each time the brake assembly is actuated.

Abstract: A hose connector has a body having a first portion adapted to receive a flexible hydraulic hose and a second portion adatped for connection to a brake actuator. A bore portion of the second body portion is arranged to provide a space large enough to contain at least a major part of any heated brake fluid returning from the actuator upon brake retraction thereby minimizing the amount of heated fluid reaching the hose.

Abstract: Lubricating oils containing oil soluble hydroxyalkyl alkanoates have been found to reduce brake noise for oil-immersed disc brakes.

Abstract: An improvement for a steering differential for a tracked vehicle comprising a liquid cooled, hydraulically operated disc brake, two of which are normally used upon the differential to brake and steer the vehicle. A number of stationary discs are keyed internally to a brake body, with a number of rotating discs dispersed therebetween and splined to a braking axle of the differential, the rotating and stationary discs being hydraulically compressed together to apply braking torque to the braking axle. Oil or other suitable liquid is pumped through the brake body and radially through grooves on the faces of the discs to prevent excessive heating of the discs and the brake.

Abstract: Hydraulically-operable rotary friction brake comprising a retarding device incorporating hydraulically actuated operating members have a hydraulic circuit including a valve whereby in periods of operation a major portion of the hydraulic flow is directed through the hydraulically actuated operating members and in periods of non-actuation only a minor proportion of the hydraulic flow is directed through the operating members.

Abstract: A continuous brake (retarder) for vehicles, especially for heavy trucks or the like, which utilizes a hydrodynamic circulatory system in the form of a driven hydrodynamic coupling whose operating fluid is conducted into an external circulatory system by way of a cooler or radiator; a separate cooler is coordinated to the hydrodynamic coupling which serves at the same time as feed pump for the operating fluid; additionally, the hydrodynamic coupling is operatively connected with a turbine in the external circulatory system which serves for the drive of a separate fan coordinated to the separate cooler.

Abstract: An annular single piston brake arrangement is disclosed for selective holding engagement of a rotatable member of a drive train. The brake arrangement includes a support structure, an annular brake piston axially reciprocably and nonrotatably mounted within the support structure, a plurality of springs mounted intermediate the support structure and the brake piston for biasing it concentrically toward peripheral brake holding engagement of the rotatable member, a fluid retractor for holding the brake piston in a disengaged condition overcomingly against the action of the springs, and a fluid actuator for biasing the brake piston concentrically towards peripheral brake holding engagement of the rotatable member.

Abstract: A brake system which utilizes a disc movably mounted on a rotating member such as a shaft, wheel hub or an axle, so that the disc may be tilted at an obtuse angle to the rotating member. A caliper forming two or more hydraulic cylinders and holding associated pistons is mounted adjacent the disc with the ends of the pistons being positioned on opposite sides of the disc. Friction pads are secured to the ends of the pistons. A master cylinder communicates with the caliper held cylinders through a fluid circuit. The fluid circuit includes a direct line leading to the master cylinder, a by-pass line leading to the master cylinder and a line leading from the cylinders of one side to the cylinders of the other side. A one way check valve is positioned in the direct line leading to the master cylinder and a shut-off valve is positioned in the by-pass line.

Abstract: A friction brake includes a clutch device operable to connect friction plates to a rotary shaft so that they rotate with the shaft when the brake is to be operated by engaging said friction plates with a set of stator plates interleaved therewith.

Abstract: In a vehicle retarder system having a retarder with discs working in oil which is continuously circulated by a pump, a tapping is taken from the oil circuit upstream of a variable but never wholly closed valve to supply oil to an actuator of the retarder. When retardation is required, the valve is partly closed to increase the pressure in the tapping and so to actuate the retarder, while the flow of cooling oil through the retarder continues.