Abstract: A brake actuator having a stone shield located within the brake actuator housing and surrounding the brake actuator piston which dampens the impact of the brake actuator piston against the end wall surrounding the end wall opening. The damping stone shield includes an annular body portion having a diameter less than the brake actuator end wall opening and opening which receives the reciprocal piston of the brake actuator and an integral radial flange which overlies the inner surface of the brake actuator end wall opening. The annular body portion of the stone shield includes a first end portion extending at least partially through the brake actuator end wall opening having an annular groove surrounding the piston and damping the impact of the piston against the end wall surrounding the end wall opening. In the preferred embodiment, the annular groove extends through the first end portion of the stone shield and is bell-shaped or tapered in cross-section having a rounded end surface.

Abstract: An improved diaphragm-type pneumatic brake actuator wherein the diaphragm is releasably secured to the piston as the diaphragm is inverted during actuation of the braking system of a vehicle thereby reducing wear of the flexible diaphragm and improving the performance of the brake actuator. In the disclosed embodiment, a rib or lip is formed on the surface of the diaphragm which receives the periphery of the piston as the diaphragm is inverted forming a mechanical interlock between the diaphragm and the piston thereby preventing spacing of the contact surface of the piston and the central portion of the diaphragm and frictional wear between the peripheral edge of the piston and the diaphragm.

Abstract: An improved brake actuator, particularly an improved sealed service chamber, having a flexible tubular seal affixed at one end in the central pushrod opening in sealed relation and surrounding the pushrod in sealed relation in the service chamber housing. The improved seal is generally hourglass-shaped including a midportion which closely circumscribes the pushrod in sealed relation and a free end portion which closely circumscribes the pushrod. A relatively inflexible generally diamond-shaped washer surrounds the midportion of the seal which improves sealing, assures concentricity of the tubular seal, prevents the seal from being pushed through the pushrod opening and provides for easy assembly of the seal and washer assembly in the service chamber around the pushrod. The improved end wall of the service chamber housing includes an offset recessed central portion surrounding the mounting bolts and relatively thin preferably V-shaped contact surfaces which generally circumscribe the recessed portion.

Abstract: A vehicle brake actuator including an improved piston assembly having a piston plate including an upstanding annular rim portion and a piston rod including a shank portion having a generally cylindrical head portion and an annular rim portion on a free end of the piston rod head portion which is deformed radially into a cylindrical internal surface of the piston plate upstanding rim portion, permanently attaching the piston plate and rod. The method includes piercing and extruding the upstanding rim portion of the piston plate and forming radially projecting teeth on an external surface of the head portion of the piston rod, driving the head portion of the piston rod into the upstanding rim portion of the piston plate, preventing relative rotation of the piston rod and head. The improved piston assembly of this invention eliminates welding, permitting finishing of the piston rod and plate prior to assembly and reduces cost.

Abstract: The brake actuator assembly of this invention significantly reduces accumulation of road debris, reduces the weight of the push rod and yoke assembly and friction between the mating parts. The brake actuator includes a housing defining a chamber having an opening through the end wall, a push rod and yoke assembly reciprocally mounted within the housing chamber and a shield located within the housing closely receiving the exterior surface of the push rod and yoke assembly which has a smooth substantially continuous external surface. In the preferred embodiment, the yoke is secured to the push rod within the housing chamber, surrounding the push rod having an elliptical exterior surface which sheds accumulation of road debris.

Abstract: A brake actuator having an improved push rod and end plate assembly which eliminates the requirement for thread adhesive and avoids deformation of the exterior surface of the push rod. The push rod includes an axial internally threaded bore through one end and the shank portion of the mounting screw includes an unthreaded intermediate portion adjacent the threaded end portion having a plurality of radial lobes which are turned into the internally threaded bore of the push rod securely retaining the end plate to the push rod under vibration loading and extreme temperature conditions. The radial lobes on the intermediate portion of the mounting screw each include an arcuate spiral lead surface and a flat generally radial following surface which requires only a relatively small torque to secure the end plate to the push rod, but a significantly larger torque to unthread the mounting screw from the push rod.

Abstract: An improved brake actuator and method of assembling a cup-shaped housing on a housing member of a brake actuator, wherein the housing member has an open end, an annular radially projecting rib adjacent to and surrounding the open end and a plurality of spaced channel-shaped transverse depressions in the radial rib extending toward the open end of the flange case, a cup-shaped metal cover including a tubular open end having an inside diameter initially less than the outside diameter of the annular radial rib of the housing member, wherein the tubular end portion of the cover is pressed telescopically over the radial rib of the housing member, thereby simultaneously deforming the tubular end portion of the cover into the channel-shaped depressions in the rib of the housing member and stretched over the radial rib, thereby preventing rotation of the cover relative to the housing member.

Abstract: An improved spring brake actuator includes an improved valve housing which incorporates pressure test points into the air supply, and further incorporates an anti-compounding valve. By incorporating the anti-compounding valve and test points directly into the valve manifold, the inventive spring brake actuator reduces the number of separate parts. The anti-compounding valve is operable to insure that there will be no compounding of the braking force.

Abstract: The present invention provides a brake actuator assembly including a housing having a generally radial annular flange portion and a cover having a generally radial annular flange portion generally co-axially aligned with the generally radial annular flange portion of the housing. A cup-shaped flexible diaphragm having an outer radial annular rim portion is disposed between the generally radial annular flange portions of the housing and the cover. A retaining element generally surrounds and compresses the generally radial annular flange portions of the housing and the cover against the rim portion of the flexible diaphragm. The rim portion of the diaphragm includes a wedge-shaped edge portion and co-axially aligned flats on opposite sides of the rim portion adjacent to the wedge-shaped edge portion aligning the flange portions of the housing and the cover. In another embodiment, a flexible brake diaphragm includes a cup-shaped flexible diaphragm having an outer radial annular rim portion.

Abstract: A brake condition monitoring system includes a central control receiving signals from each of the several brake actuators mounted on a vehicle. The control receives all of the signals, and sends a single signal to a display in the cab of the vehicle indicative of which of the brake actuators may be evidencing a malfunction. The signals from each brake actuators are unique such that the control can determine which brake actuator each signal is from. The control is also capable of monitoring conditions other than movement of a push rod.

Abstract: An improved mounting bolt for attaching brake actuators to the frame of a vehicle includes a head having outermost portions which contact the service chamber housing, and inner portions which are spaced from the housing. The bolt spreads the force from carrying the brake actuator over a greater area on the service chamber housing and away from the bolt hole. The bolt preferably has a generally rectangular head.

Abstract: A brake actuator includes an inelastically deformed separate clamp band holding the brake actuator housing portions together. The actuator is formed by cutting the clamp band from a roll of thin stainless steel. The cut portions are formed to have an L shaped section. The short L end is then placed on one of the flanges of the brake actuator housing members. The other end of the clamp band is then deformed inwardly to secure the brake actuator housings together. The invention results in a relatively low cost clamp band. The clamp band has particular application on the service side of the spring brake actuator, although it would also be useful on the emergency side.

Abstract: Brake actuators are provided with self-centering diaphragms. In one embodiment, the diaphragm is provided with a centering bead radially outwardly of a sealing bead. The centering bead ensures the diaphragm is properly centered prior to the brake actuator housings being secured together. In a second embodiment, the self-centering structure includes structure fit into mating structure in one of the brake actuator housings to ensure the diaphragm is properly centered. The self-centering structure ensures the brake actuator diaphragms are properly centered before connection of the two brake actuator housings. This invention is particularly useful in the type of brake actuator housings having deformed housing portions.

Abstract: An improved brake actuator is fully sealed against ingress of liquid or other contaminants. Separate breather tubes selectively communicate each of the pressure ports to the non-pressurized sides of the service and spring chambers. The separate breather tubes provide clean air into the non-pressurized chambers. Relief valves are positioned in each of the breather tubes. The pressurized ports may be reconfigured into two configurations such that the source of pressurized air may be connected to either of two orientations. In addition, a seal closely receives the push rod such that the non-pressurized chamber of the service side is fully sealed against ingress of liquids.

Abstract: In a method of forming tamper-resistant brake actuators, the ports for connecting air pressure sources to apertures within the central housing of the brake actuator are bolted to the central housing after the brake housing members have been inelastically deformed together. In this way, the deformation tools utilized to deform the housing members will not contact the air pressure ports. In the past, brake actuators have required spacing the deformation tools from the ports to avoid damaging the ports. This has required that the central housing be undesirably long. With the inventive method, the deformation is performed prior to attachment of the ports. Thus, the axial length of the central housing may be greatly reduced over the prior art. Once the deformation is completed, the ports are then bolted to the central housing. In this way, the length of the central housing and the amount of material required by the central housing are greatly reduced.

Abstract: A brake release tool incorporates a two-part structure wherein a portion accessible from outside the brake actuator does not move axially away from the brake actuator during caging. In this way, less room is necessary outwardly of the brake actuator housing than has been required in the prior art. An operator turns an outer bolt, which turns a threaded inner nut. The threaded inner nut moves axially to contact a piston, and moves the piston to cage the power spring. The bolt need not move axially outwardly, although in one embodiment it may move slightly axially inwardly as the spring is caged to provide a visual indication that the spring is not uncaged.

Abstract: A unique indicator system is incorporated into a release tool for a spring brake actuator. The indicator provides an indication of when the release tool has is fully released. The release tool is preferably of the type wherein a threaded member does not extend outwardly of the actuator during caging of the power spring. The inventive indicator is biased outwardly of the actuator when the release bolt has even partially caged the power spring. It is only when release bolt is fully released that the indicator is pulled inwardly. Thus, an observer has a visual indication of when the power spring caging mechanism has been fully released.

Abstract: A spring brake actuator includes a unique release bolt having two distinct threaded portions. A first-threaded portion is received in a threaded insert in the brake actuator outer housing. The second-threaded portion has its threads extending in an opposed direction to the first-threaded portion and is threadably received within a nut caging member. The nut is received in a bore in the push rod and constrained against rotation relative to the push rod. The nut moves axially within the push rod. The second-threaded portion rotates with the entire release bolt. When the release bolt is rotated, the first-threaded portion moves outwardly of the threaded insert, and the nut moves with the release bolt. At the same time, the second-threaded portion is rotating within the nut, and the nut moves axially relative to the second-threaded portion. The nut is moving axially due to two actions of the release bolt.

Abstract: An improved spring brake actuator includes a dome extending into the service chamber from the center housing. The spring chamber push rod is formed with a plate having a cross-section corresponding to the dome. The service chamber diaphragm as well as the service chamber piston are also formed with surfaces that correspond to the shape of the dome. The surfaces "stack up" to ensure alignment between the spring chamber push rod and the service chamber push rod. The use of the dome also provides additional stroke to the spring chamber push rod without requiring additional axial length for the overall brake actuator.

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