Abstract: The present invention is directed to a gladhand connector having multiple ports and an integrated filter. The connector has a base that includes an air hose connector clamp on a first surface, and a first access port extending from the first surface toward a second surface, and a second access port on a bottom surface. The access ports are in fluid communication with an intermediate conduit configured to direct air received from an air hose through the housing. The connector also comprises a receptacle adjacent the first access port and in fluid communication with one of the access ports. The receptacle is configured to receive a pressure sensitive, removable and replaceable filter assembly that is configured to filter debris. The filter assembly is displaceable by air pressure of received air. The connector further comprises a mounting bracket configured to be attached to a vehicle.

Abstract: A valve comprising an inlet port, an outlet port, an exhaust port and a diaphragm disposed between the inlet and exhaust ports which is moveable, in response to air pressure within the valve, between a first position in which it seals the exhaust port and a second position in which the exhaust port is open, there being one or more projections associated with the exhaust port on which the diaphragm is able to rest in its first position.

Abstract: Derailment control system for railway vehicles that, in addition to detecting and issuing a warning of said derailment, provides control over the brake of the derailed vehicle or vehicles and provides additional emergency braking and/or a warning to the driver's cab, said system having a main unit (1) to which are joined: an inertia sensor or detector (8) designed to detect derailments, an indicator (9) or device responsible for indicating that the derailment control system has been triggered and for keeping the system activated, a stopcock (10) that deactivates the derailment control, and a bottom connection point (11) for testing that makes it possible to simulate a triggering of the system via a threaded eyebolt, facilitating verification of proper operation both during bench testing and when the system is installed on the vehicle (7), and a device (39) situated at the exhaust outlet through which the automatic brake pipe (ABP)(5) is vented when said derailment is detected.

Abstract: A valve for use in a pneumatic system of a truck-trailer having a source of air under pressure, a reservoir, at least one spring brake unit and a brake service line is provided. The valve comprises a housing, a pressure protection valve portion, a spring brake actuation valve portion and an anti-compounding valve portion. The housing has a supply passage in communication with the source of air under pressure. The pressure protection valve portion is operably disposed within a first chamber of the housing. The first chamber has an inlet in communication with the supply passage and an outlet in communication with the reservoir. The pressure protection valve portion is configured to selectively block the flow of pressurized air from the supply passage to the reservoir through the first chamber until a predetermined pressure is reached. The spring brake actuation valve portion is operably disposed within a second chamber of the housing.

Abstract: A valve comprising an inlet port, an outlet port, an exhaust port and a diaphragm disposed between the inlet and exhaust ports which is moveable, in response to air pressure within the valve, between a first position in which it seals the exhaust port and a second position in which the exhaust port is open, there being one or more projections associated with the exhaust port on which the diaphragm is able to rest in its first position.

Abstract: A valve for use in a pneumatic fluid system, such as an air brake system, is disclosed. The valve provides for fast release of pneumatic fluid from the delivery cavity through the exhaust port upon cessation of flow from the pneumatic fluid reservoir through the supply cavity. The valve includes a flow diverter that restricts fluid flow from the delivery cavity to the supply cavity when pneumatic fluid pressure in the supply cavity is less than that in the delivery cavity with minimal restriction of flow from the supply cavity to the delivery cavity when pressure in the supply cavity is greater than in the delivery cavity.

Abstract: A combination valve assembly provides dual functionality within a single valve housing. In one example, the valve operates as a combination inversion valve and quick release valve. In another example, the combination valve operates as an inversion valve and a relay valve. The valve is particularly useful for controlling the operation of a spring applied, air release brake actuator in a heavy vehicle braking arrangement. A valve designed according to this invention preferably also provides anti-compounding features.

Abstract: A self-cleaning feature is provided for a trailer ABS modulator. Direct exhaust is provided through the piston or diaphragm to establish control line and control volume drain capabilities. This provides for moisture removal from the control line or control volume. Quick exhaust during normal service braking is also improved and, likewise, exhaust during the ABS mode is improved.

Abstract: A valve assembly for selectively controlling application of a spring brake in a truck brake system having primary and secondary circuits is provided. A spring brake valve is modified to incorporate a balance piston having an integral quick release valve. This reduces the number of components, complexity, and service problems while maintaining all of the advantages associated with monitoring the function of the primary circuit.

Abstract: A pilot mechanism for improving operation of various functions of the pneumatic brake of a train. The mechanism includes solenoid valves, controllable by either a radio/battery mode of operation or a train wire system mode of operation. The solenoid valves can be interposed in various passages in fluid communication with passages of a conventional ABD control valve, as modified to enable operation of the invention, to permit substantially immediate venting of air in those passages to atmosphere.

Abstract: Apparatus for indicating the condition of hand brakes on railway cars and for applying and releasing railway car parking or hand brakes automatically in response to predetermined conditions including movement of a train, wayside conditioning apparatus, wayside operating mechanism, a signal controlled by an operator and performance of predetermined railway operating procedures, such as completion of an air brake test procedure. The apparatus may respond to mechanical, electrical and electronic signals and may operate on pneumatic or electric power provided from the service air brake system of a train or from a source of power outside of such air brake system.

Abstract: A system is disclosed to selectively initiate braking at a rear section of a railway train upon initiation of a selected front braking condition at the front section of the railway vehicle. The system utilizes an air sensor preferably constructed in the form of an insect excluder device to detect release of brake pipe air from an exhaust port upon initiation of braking at the front section of the vehicle. An appropriate signal is produced by the air sensor, thus permitting detector circuitry to detect that front braking has been initiated. A transmitter, typically located in the cab of the locomotive, is electrically connected to the detector circuitry. When the detector circuitry indicates that the selected front braking condition has been initiated, the transmitter transmits a brake initiation signal to a receiver located at the rear of the vehicle. The receiver then actuates pneumatic braking equipment at the rear to initiate rear braking.

Abstract: A full function brake valve for a semi-trailer is contained within a single housing and provides ports for receiving supply air and control air, and for delivering and receiving air from reservoirs, service brakes and spring brakes, and delivering air to an exhaust. The internal valves include a reservoir check valve and a relay valve to respectively pressurize a reservoir and to deliver supply air to service brakes. A secondary reservoir is supplied via a secondary reservoir check valve and a secondary reservoir outlet in the full function valve, or in a secondary relay valve, and is controlled by a secondary relay valve module to provide a redundant braking system for additional safety.

Abstract: A simplified and less-costly quick-release valve with controlled hysteresis for a vehicle spring-set air-release parking brake system lengthens the operating life of the valve, reduces energy consumption, extends compressor life and alleviates noise problems. The valve comprises a valve body and a plurality of internal passageways each of which is selectively connectable to at least another of the passageways. The selective connection is controlled by an integrally-formed flexural spring-brake-control release diaphragm within the valve body and disposed to either isolate or selectively connect the passageways depending on the relative pressure conditions within the passageways and respective areas of the diaphragm exposed to the pressures. The components are designed so that the normal variations or cycling of the supply or intake pressurized air does not cause cycling of the pressure in the spring-brake chambers.

Abstract: A pilot mechanism for improving operation of various functions of the pneumatic brake of a train. The mechanism includes solenoid valves, controllable by either a radio/battery mode of operation or a train wire system mode of operation. The solenoid valves can be interposed in various passages in fluid communication with passages of a conventional ABD control valve, as modified to enable operation of the invention, to permit substantially immediate venting of air in those passages to atmosphere.

Abstract: A brake system (20) comprising: a master cylinder (26) and a pump (12) for selectively pressurizing an associated brake cylinder or cylinders; a motor (14) for powering the pump; a control circuit (16,90) for modulating motor speed in response to a signal indicative of desired braking effort and actual braking effort; and a control valve (30) responsive to master cylinder pressure for controlling pump flow and for permitting the decay of pressure in the brake cylinders.

Abstract: A security lock apparatus for engagement with and locking on a break line coupler of the type having a housing with a central seal, a tongue projecting laterally in one direction and a crown mounted on the opposite side thereof and formed with a turned back cap defining a downwardly opening groove. A lock body is formed with an under surface defining a seat for overlying the seal and having a downwardly depending flange formed on one side thereof with a turned back rim defining an opened ended track for receipt of such tongue. Projecting from the opposite side of such body is a rail formed with an upturned arcuate rib for sliding receipt in the groove.

Abstract: A brake control system having a vent valve device in which a control piston is effective to unseat a normally closed vent valve to provide rapid exhaust of brake pipe pressure to either propagate an emergency brake application in response to brake pipe pressure on one side of the piston being reduced at an emergency rate or to initiate an emergency brake application when pressure on the opposite side of the piston is increased by an auxiliary pilot valve connected to a second main reservoir at a higher pressure.

Abstract: This invention relates to release/relief valves, trailer brake release valve, and apparatus for equalizing pressure and absorbing shock, as they pertain to pneumatic brake systems for buses, trucks, and trucks/semi-trailers, singular and in multiple combinations in automotive air brake installations; and more particularly to a differential pressure regulator quick release valve that employs a dilivery channel for directing and centralizing fluid pressure differentials to its base housing and the same delivery channel directing the exhaust of fluid pressure to its quick release ports.

Abstract: A slip control mechanism of a car has a hydraulic booster for driving a master cylinder for providing hydraulic pressure to a first brake provided for each driven wheel, a second brake provided for each driving wheel, a slip detection device for detecting the slip of driving wheels, a slip control device for operating the second brake, based on signals from the slip detecting device, by using the operating oil of the hydraulic booster as operating oil of the second brake so as to reduce the slip of the driving wheels, the control device comprising a pressure control valve for controlling hydraulic pressure of the operating oil of the second brake, including a pressure reducing valve for reducing the hydraulic pressure of the operating oil of the second brake, detection device for detecting completion of the slip control by the operation of the second brake, and a release device for opening the pressure reducing valve for a predetermined time so as to release the operating oil of the second brake on the occasi

Abstract: A pressurized fluid control module is provided for a tractor-trailer brake system to effect the appropriate braking function.

Abstract: A pressure piloted release valve (80) is disposed within an adaptive braking system (10) having shuttle valves (34, 44, 54, 64). The release valve (80) provides for a quick release of fluid pressure buildup within the adaptive braking system (10) so that an associated shuttle valve (34, 44, 54, 64) will return to a normal braking position and cease restricting fluid flow with an associated wheel brake (30, 40, 50, 60). The release valve (80) includes a differential area release valve (100) received with a valve body (83) having a stepped bore (90). The valve body (83) includes a frustoconical-shaped body chamber (120) with a radial passage (124) such that displacement of the release valve (100) results in a second end (105) of the release valve (100) engaging sealingly a sloped end wall (102) of the body chamber (120) to prevent fluid flow through a longitudinal through passage (101) of the release valve (100) to a receptacle chamber (85) via the radial passage (124).

Abstract: A valve has a direct flow passage extending therethrough. A flexible diaphragm (170) is positioned between a main valve seat (156) and an exhaust seat (172). Flow of pressurized air into the valve (110) through the inlet port (142) deflects the diaphragm (170) away from the main seat (156) and seals it against the exhaust seat (172). Higher pressure at the delivery port (144) than the inlet port (142) move the diaphragm (170) away from the exhaust seat (172) and against the main seat (156). A shunt passageway communicates portions of the flow passage on opposite sides of the diaphragm (170) to prevent maintenance of residual positive pressure on the delivery side of the diaphragm (170). The shunt passageway includes a groove (161) along the frustoconical main seat (156) and peripheral cutouts (171) on the diaphragm (170). In one embodiment (210) of the valve, a push member (272,276) moves against the diaphragm (270) to help unseat it from the exhaust seat (272).

Abstract: A continual type quick service valve adapted to be independently mounted on a railway car to provide local, supplemental venting of the car brake pipe pressure, as long as the brake pipe pressure continues to be reduced externally. This quick service venting of the brake pipe pressure is achieved utilizing a single piston actuated exhaust valve that is either cyclically-operated between open and closed states or is held open continuously depending upon the degree of brake application in effect. By selective tuning, the open duration of the exhaust valve can be made to exceed the duration the exhaust valve is closed during each cycle of operation or to remain open for the duration of the external brake pipe pressure reduction to achieve high operating efficiency.

Abstract: An electrically-controlled motor vehicle brake system, which responds to fluid pressure supplied from a common source. The system includes an electronic control system to process information and issue brake commands. A brake cylinder, to apply and release brake pressure on each respective wheel brake, receives pressure from at least one solenoid valve, connected to receive pressure from the source. The pressure is communicated to the brake cylinder of each respective wheel brake upon receipt of a control signal from the control system. A brake power selector includes both a pedal-operated brake valve, connected on an input side to receive pressure from the source, and connected on an output side to a ventilation portion of the solenoid valve for modulating the brake pressure, and an electrical frequency selector is connected to provide an input signal to the electronic control system upon actuation by an operator of such vehicle during a brake application.

Abstract: A double solenoid valve especially for anti-lock braking (ABS) applications has a normally open conduit for connection to a first port fluidically in series with a normally closed conduit between second and third ports. A slow two-way path continuously connects the second port. The double valve when used in ABS can handle incipient locking, actual locking, quick releasing to normal after emergency anti-lock action, and purge modes.

Abstract: An automatic air brake system for accelerating the exhaustion of the pressure in the brake line of a train for more rapidly applying the brakes on all the railway vehicles. A flow rate detector connected to the brake line of the locomotive to detect the flow of air in the brake line. A pilot chamber of a relay valve is supplemented when a flow signal from the flow rate detector exceeds a predetermined value and the supplementation is stopped when the flow rate drops below a predetermined value. The pilot chamber is exhausted in response to a brake application command and is pressurized in response to a brake release command. The relay valve includes an output chamber which is connected to the brake line of the locomotive, and the brake line pressurizes and exhausts the output chamber in response to the pressurization and exhaustion of the pilot chamber.

Abstract: An automatic air braking system for a railway train having a flow detector for sensing the flow of pressurized air in the brake line during a brake release command time. A pilot chamber located in a relay valve which is pressurized when a signal from the flow detector exceeds a first predetermined pressure value and which stops the pressurization when the flow signal drops below a second predetermined pressure value. The brake line runs from the lead unit or locomotive of the train and through the railway vehicle or freight cars connected to and pulled by the lead unit or locomotive. The relay valve which is an automatic-lapping-type is located in the lead unit or locomotive in which the pilot chamber is exhausted in response to the reception of a brake release command. An output chamber, which is located in the relay valve, is connected to the brake line of the lead unit or locomotive.

Abstract: The acceleration apparatus for connection with a pilot operated compressed-air brake comprises a tap-off valve which vents the main air line or conduit at the beginning of the braking procedure. This tap-off valve is opened by an actuator or actuating mechanism via a disengageable intermediary member. By employing a rotationally symmetrical plunger or push rod which is pivoted into the operative position thereof by a spring and deflected by an interrupter piston, the construction of the disengageable intermediary member can be substantially simplified. The plunger or push rod possesses at the one end thereof a cam or pin and a substantially conical surface.

Abstract: An improved freight brake emergency valve providing improved stability against undesired emergency brake applications without degradation of emergency sensitiveity by increasing the "breathing" range of travel of the emergency piston to allow a momentary random brake pipe pressure fluctuation to dissipate, and by providing a volumetric chamber between the quick action chamber "breather" port connection at the slide valve/seat interface and the "breather" choke in order to obtain a momentary fast reduction of quick action chamber pressure to counteract a brake pipe pressure fluctuation during pressure equalization between the quick action chamber and the added volumetric chamber.

Abstract: A freight brake control valve device having an improved quick service function provided by suppressing premature cut off operation of the quick service limiting valve. In one embodiment of the invention, this is accomplished by connecting the quick service volume pressure to the underside of the quick service limiting valve piston during preliminary quick service to counteract the pressure pulse on the opposite side of the piston that occurs during the transition between the preliminary and secondary stages of quick service. In a second embodiment, pressure is created at the underside of the quick service limiting valve piston by dashpot action of the piston itself.

Abstract: A housing has a triple valve coaxially adjoining a proportioning piston valve end-to-end, the triple valve having supply, lap and exhaust positions for governing pressure in a brake cylinder; and the proportioning piston valve being operable to sense an emergency signal in a brake pipe for delivering fluid from an emergency reservoir to the brake cylinder after the brake cylinder has been charged to substantially service pressure from an auxiliary reservoir. The triple valve and the proportioning valve piston are biased in opposite directions by the same biasing spring.

Abstract: A hydraulic control device for an anti-skid brake system for a vehicle, including a solenoid-operated directional control valve for communication of a pressure chamber in a hydraulic actuator, selectively with a hydraulic power source and a reservoir, and a solenoid-operated flow control valve disposed between the directional control valve and one of the pressure chamber, hydraulic power source and reservoir, the hydraulic control device being operated to effect rapid and slow rise and fall of a pressure in the hydraulic actuator, in response to a slip ratio of a wheel of the vehicle. The flow control valve comprises a flow restrictor which permits a restricted flow of a fluid through the valve even when its valving member is seated on a valve seat in which a valve hole is open. The flow restrictor is provided in one of various forms except an ordinary orifice with a small diameter.

Abstract: A quick release valve for a vehicle fluid pressure braking system includes a housing having inlet, exhaust and delivery ports. A bead circumscribes the inlet port to provide a valve seating area for a flexible diaphragm within the valve housing, and the exhaust port includes a projecting portion which preloads the flexible diaphragm into engagement with the bead circumscribing the inlet port. Accordingly, pressure variations between the ports cannot force the flexible diaphragm to vibrate to create an undesirable honking noise. Furthermore, the circumferentially extending bead assures a pressure-tight seal with the flexible diaphragm, and also establishes a predetermined sealing area for the diaphragm, thereby reducing valve hysteresis by preventing sealing of the diaphragm at varying areas on the housing.

Abstract: A pulsating brake accelerating device for an indirectly operating air brake for rail vehicles has a pulsator (12), which is attached to the brake pipe (BP) via a jet (23). The pulsator (12) forms a mixed pressure from two pressures. One of the pressures is formed by the pressure of the brake pipe (BP) via a jet (23) and the other pressure is formed by pressure from a control chamber (QAC) via another jet. At every braking level the pulsator (12) drains mixed pressure pulses off into the atmosphere, while at the same time the brake pipe pressure and the control chamber pressure is lowered via the mixed pressure pulsator (12). The mixed pressure can consist of two valves (14, 15). The control element (4) of the brake accelerator unit can be the emergency brake piston, which monitors several valves, one of which is the pulsator-excitation valve (8).

Abstract: Brake control valve system for rail vehicle air brake, comprising an emergency brake piston (7) having a first piston chamber (9) loaded by the quick action chamber with a much greater volume than its second piston chamber (8) loaded by the brake line. The effective pressure surfaces of the service brake piston and emergency brake piston are substantially identical. The emergency brake piston controls a first quick action exhaust valve (15) for venting smaller amounts of quick action air per unit of time, as well as a valve device (14) containing a second quick action exhaust for venting larger amounts of quick action air. Valve device (14) is pneumatically connected to the control piston (19) of a high pressure/emergency exhaust valve system (16) which operates only upon emergency braking. Piston (19) contains a nozzle (22) through which pressure remaining in the quick action chamber (10) during emergency braking is evacuated in a predetermined time.

Abstract: A quick release valve for releasing the locomotive automatic brake independently of the train brakes when an AB/D type freight brake control valve is used on the locomotive. A release valve normally establishes a fluid control passage between the control valve and a relay valve that controls the locomotive brake pressure. When a quick release is made, the release valve is actuated to interrupt this fluid control passage and exhaust the relay valve portion of the passage to release the brakes. At the same time, a dissipation valve is effective to exhaust auxiliary reservoir pressure. If the quick release is made of a service application, the exhaust of auxiliary reservoir pressure will cause the control valve to exhaust the control valve portion of the control line and thereby prevent an automatic reapplication of the automatic brake following termination of the quick release function.

Abstract: A pulsating brake accelerating device for an indirectly operating air brake for rail vehicles has a pulsator (12), which is attached to the brake pipe (BP) via a jet (23). The pulsator (12) forms a mixed pressure from two pressures. One of the pressures is formed by the pressure of the brake pipe (BP) via a jet (23) and the other pressure is formed by pressure from a control chamber (QAC) via another jet. At every braking level the pulsator (12) drains mixed pressure pulses off into the atmosphere, while at the same time the brake pipe pressure and the control chamber pressure is lowered via the mixed pressure pulsator (12). The mixed pressure can consist of two valves (14, 15). The control element (4) of the brake accelerator unit can be the emergency brake piston, which monitors several valves, one of which is the pulsator-excitation valve (8).

Abstract: This invention relates to a valve assembly for a railway braking system, including a brake cylinder pressure-maintaining valve which, during brake application, takes air from the brake pipe and feeds it into the brake cylinder until it reaches minimum brake pressure. To avoid the need for an extra valve, the brake cylinder pressure-maintaining valve is used as a quick service bulb exhaust valve during brake release and member are provided to ensure that the brake cylinder pressure maintaining valve opens immediately on brake release. Once the brakes have been applied, pressure in the brake cylinder is maintained from the quick service bulb 59. Brake cylinder exhaust pressure taken from a point 124 after the brake cylinder exhaust valve 50, but before the brake cylinder exhaust choke 70, is directed to chamber G above the inshot and brake cylinder-maintaining valve diaphragm 131. Since the pressure in port 124 upstream of the brake cylinder exhaust choke 70 attains a pressure well within 10 p.s.i.

Abstract: Release valve apparatus capable of being actuated by the vacuum that can be created in a main air line (1) for indirect air brakes of rail vehicles, comprising a release valve (12) in a connection (pipes 8, 9) from the brake control valve (3) to the brake cylinder (10). The release valve (12) contains a piston controlled two-way valve (24, 27, 28), which unblocks the passage in the off position of the release valve (12). In the actuated position, on the other hand, it blocks passage and vents the connecting segment (pipe 9) on the brake cylinder side. The piston (13) of the release valve (12) is loaded in the off position operating on a smaller piston area by main air line pressure, and by opposing pressure in an admission area (15) which is under atmospheric pressure in the off position and during the switching process to the operating position, and in this position is impacted by pressure in the connecting segment (pipe 8) leading to the brake control valve (3).

Abstract: A quick release valve comprising a main casting (1) and a closure member (5, 27, 45) crimped on after insertion of a rubber valve member (9, 30, 48) and an `O` ring seal (13, 39, 49).

Abstract: A pressure reducer for hydraulic brake systems comprising a valve formed by the head of a spring-loaded piston and by a sealing ring which is urged by a spring against a step of the housing. Arranged between the spring and the sealing ring is an engaging plate which is carried along by the piston after the piston has travelled an amount smaller than the valve stroke. This results in an exactly defined valve stroke and at the same time results in a quick opening of the valve upon decrease of the inlet pressure.

Abstract: A brake control device has a selective release accelerator which responds only to a normal release subsequent to an increase of brake line pressure initiated by the operator's brake valve. A first piston has one side subjected to air line pressure and the other side subjected to pressure in an auxiliary reservoir. The first piston controls an inlet valve to connect the emergency reservoir to the brake line. A second piston has one side subjected to brake line pressure and its other side to pressure in the auxiliary reservoir and monitors the first piston. The side of the first piston subjected to auxiliary reservoir pressure is connected through a throttled connection to the auxiliary reservoir when the brake line pressure is smaller than or equal to the auxiliary reservoir pressure. This throttled connection is interrupted when the brake line pressure reaches a predetermined value higher than the auxiliary reservoir pressure.

Abstract: This invention relates to a railway vehicle continual quick service valve device that embodies two abutments normally subject on their respective opposite sides of the pressure in a train brake pipe and in a control chamber. Upon a reduction of brake pipe pressure on one side of these abutments, one abutment operates a valve to release fluid under pressure from the brake pipe and the brake pipe side of the other abutment to atmosphere whereupon this other abutment operates a valve that releases fluid under pressure from the control chamber and the control chamber side of both abutments to atmosphere. These abutments then operate their respective valves to cut off venting of fluid under pressure from the brake pipe and the control chamber to atmosphere. If the reduction of brake pipe pressure on the one side of the one abutment continues, the above-described cycle reoccurs so long as fluid under pressure is released from the brake pipe.

Abstract: A brake accelerator has a control chamber connected through a throttle orifice to a brake line. The brake system includes a control valve in which is an emergency brake piston one side of which is subjected to brake line pressure and the other side of which is subjected to pressure in the control chamber. The emergency brake piston, as a function of a pressure drop in the brake line, opens a brake line outlet valve so that air flows from the brake line through an inlet valve. The inlet valve is held by a control piston in its open position at the start of a pressure drop in the brake line and the air is flowed into a chamber to form a control pressure.

Abstract: An upgraded railway freight car brake control valve device comprises a novel emergency valve portion that embodies therein a minimum number of simple and inexpensive poppet valves, one of which is a double seated valve, that replaces yet performs the same functions heretofore performed by more expensive slide type valves which slide valves, and the flat seats upon which they slide as they are shifted from one position to another, in their manufacture require a considerable amount of accurate machining thus increasing the cost of the valve device of which they are an important part.

Abstract: In a proportioning type control valve device in which a piston valve assemblage is actuated to service position in accordance with a differential between brake pipe and control reservoir pressures on opposite sides of an actuating piston abutment forming a part of the piston valve assemblage, there is provided on the control reservoir side of the piston abutment a bellows device that is normally held under compression by the presence of control reservoir fluid pressure so as to be normally disengaged from the piston and engageable therewith only in the absence of control reservoir pressure to serve as the reference against which reductions in brake pipe pressure are measured to establish the actuating force on the piston abutment. When disengaged from the piston abutment under the influence of the control reservoir pressure, the bellows holds a control spring housed within the bellows under compression.

Abstract: A vehicle air brake system includes spring set air released parking brakes to which air is supplied through a pressure holding valve which maintains the air chambers of the parking brakes at a predetermined pressure even though the air brake system may be at operating pressures substantially lower than the predetermined pressure. When the air pressure in the air brake system falls below operational levels, the pressure holding valve responds to release the air from the parking brake chambers.

Abstract: A brake accelerator for drawing off air from the brake line of an air brake system for railway vehicles has a piston one side of which is subjected to air pressure in the brake line and the other side is subjected to a control pressure in an expansion chamber connected to the brake line through a throttle opening. A first valve is in a connection between the brake line and a pressure accumulation chamber connected to the atmosphere through a second throttle opening. The first valve is actuated by the first piston when the control pressure exerted on the first piston is predominant. A second valve opens subsequently to the first valve and is located in a connection leading from the expansion chamber through a throttle opening to the atmosphere. The second valve is actuated by a second piston loaded by the pressure in the pressure accumulation chamber in the direction to open the second valve against the force of a spring urging the second valve into its closed position.

Abstract: A fluid brake control system is disclosed for having an improved brake cylinder release control device for use in association with a brake control pipe, a fluid reservoir, and a service valve. The control device has a housing containing a differential abutment subject to actuation from a normal position by differences in pressure between a release spring in a chamber on one side of the abutment and pressure selectively applied to the abutment in another chamber on the opposite side of the abutment. A plurality of poppet type valves operated by longitudinal push rods connected by a bridge are provided in the chamber on each side of the abutment, the bridge being actuated at a midpoint by the abutment.