Abstract: A two-ply pressure plate (36) for use in an air brake system (10) for a vehicle, such as a bus, truck or the like, is shown. The two-ply pressure plate (36) includes a diaphragm plate (92) which abuts a diaphragm (32) of an air brake system (10) and a support plate (98) which abuts the rear surface of the diaphragm plate (92). A control rod (18) is welded to the support plate (98) and diaphragm plate (92). Some form of mechanical or metallurgical interconnection between the support plate (98) and diaphragm plate (92) is formed in between the mounting point of the rod (18) and the outer perimeter of the smaller of the two plates.

Abstract: An air-operated diaphragm spring brake actuator has a pressure plate formed entirely of plastic. The diaphragm is secured to the pressure plate by ultrasonic welding. The pressure plate also has a central hub which centers the opening and receives the actuator rod in press-fit engagement.

Abstract: A connector for a spring brake actuator comprises a threaded bolt having at least one flat portion on an outer surface thereof, a nut having a threaded central aperture threaded onto the bolt, and an embossment on the nut, extending inwardly of the central aperture to frictionally engage the flat portion of the bolt, so that the embossment prevents rotation of the nut with respect to the bolt. A method for fixedly attaching a nut onto a bolt comprises forming a flat portion on an outer surface of the bolt, threading the nut onto the bolt in alignment with the flat portion, and pressing inwardly of the nut with a punching tool to cause a portion of the material of the nut to extend inwardly of the central aperture forming an embossment in engagement with the flat portion on the bolt to hold the nut rigid with respect to the bolt.

Abstract: A brake actuator (10) for a vehicle comprises a service brake housing (14), a tandem spring brake housing (16) and a diaphragm (52), dividing the interior thereof into a first spring chamber (62) and a second spring chamber (63). In one embodiment, the first spring chamber (62) is completely sealed from the environment, being open only through a hollow actuator rod (56) connected to the diaphragm (52) and extending from the first spring brake chamber (62) into the service brake housing (14). A control valve (300) in the actuator rod (56) controls flow through the actuator rod (56) and is closed when the actuator rod (56) is retracted and also when the actuator rod (56) is extended to apply the brakes. The control valve (300) is open only as the diaphragm (52) and actuator rod (56) are moving.

Abstract: Measuring the force of a spring (28) in a spring brake actuator (10) comprising a housing (14) having an end wall (46), a spring plate (30) within the housing (14), the spring (28) being disposed between the spring plate (30) and the housing end wall (46) and a caging bolt (34) extending from the spring plate (30) through the housing end wall (46) and having a nut (44) thereon with a gauge between the caging bolt nut (44) and the housing (14). The gauge comprises a pressure-responsive element which detects the compressive force between the nut (44) and the housing (14) and generates a signal responsive thereto. An indicator (86) is coupled to the pressure-responsive element and visually displays the force on the spring (28) as a function of the compressive force signal. An embodiment of the gauge (50) comprises a body (52) having a bore (58), a piston (64) received within the bore (58) defining a chamber (74) between the piston (64) and the body (52) and a fluid (72) in the chamber (74).

Abstract: A spring break actuator (10) with a cast aluminum adapter (74) partially defining tandem spring brake and service brake portions has several corrosion fuses on the adapter. Each corrosion fuse is defined by a recessed or thinned area which does not compromise the structural integrity of the adapter.

Abstract: A nut and bolt assembler comprises a threaded bolt (78a) having a proximal end (140) with a knurled outer surface (142). A nut (144) is press fit onto the bolt knurled proximal end (190) to prevent rotation of the nut (144) with respect to the bolt (78a). Preferably, the knurled outer surface preferably comprises axial splines (142). The connection is most useful on the proximal end of a caging bolt (78a) in a spring brake actuator (10) having a hollow actuator rod (60) into which a head (86) at a distal end of the caging bolt (78a) is positioned with the proximal end (140) of the caging bolt (78a) extending out of the brake actuator through a threaded aperture (77) in an end portion of a brake actuator housing (52). A washer (148) can be provided between the nut (144) and the brake actuator housing (52) to prevent foreign material from entering the break actuator housing (52) through the threaded aperture (77).

Abstract: An air-operated combination diaphragm spring brake has a service chamber in tandem with a spring chamber. The service chamber being separated into an upper and lower section by a first elastomeric diaphragm. The spring chamber is separated into upper and lower sections by a second elastomeric diaphragm. A lever type stroke indicator is positioned within either or both the lower sections of the service chamber and the spring chamber.The stroke indicator in the service chamber pivots about a pin when contacted by a plate associated with the service push rod when the brakes are applied, resulting in a portion of the stroke indicator to extend beyond the periphery of the service chamber housing and provide a visual indication of the need to inspect the brake system.

Abstract: A bearing (104) is mounted to the caging bolt head (86) within a hollow actuator rod (60) of a spring brake actuator (14). The bearing (104) is self-lubricated to guide movement of the actuator rod during application and release of the spring brake and to minimize friction.

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 fluid-operated brake actuator having a check valve in the spring chamber to equalize the pressure on opposite sides of an operating movable diaphragm. The brake actuator comprises a service brake housing divided into first and second service chambers by a diaphragm or piston, and a spring brake housing arranged in tandem with and attached to the service brake housing, also divided into a first and second spring chambers by a diaphragm or piston. The check valve connecting the first and second spring chambers blocks flow between the first and second chambers when the second spring brake chamber is pressurized and opens up flow between the two chambers when the second spring chamber is depressurized.

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: A fluid-operated brake actuator having a hollow actuator rod between a spring chamber of a spring brake housing and a spring chamber of a service brake housing incorporates a valve within the actuator rod. The valve isolates the two spring chambers from each other in normal operation and releases a vacuum in the spring brake housing spring chamber when the spring brake is activated. A separate one-way check valve mounted in a well of the spring brake housing permits fluid to exhaust from the spring chamber to atmosphere and prevents contaminants in the atmosphere from entering the spring chamber.

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: 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.