Abstract: The present invention is an improved secure coupling for vehicle brake actuator units that allows for a stronger and more efficient units having the same or smaller overall profile. The coupling is used between the housing cup of either a service brake actuator or an emergency brake actuator, or both, and a corresponding adaptor where the housing cup(s) and adaptor are made of dissimilar metals. In the coupling, the cylindrical wall of the housing cup is substantially vertical, and the corresponding annular edges of the adaptor cup are provided with a uniquely shaped engagement structure. This structure allows the edges of the elastomeric diaphragm deployed in the actuator to extend away from the coupling at a substantially vertical angle, making available more surface area of the diaphragm to press against a pressure-transmitting plate inside. This allows the brake actuator unit to transmit more force, and/or to employ a stronger emergency brake spring, without increasing the size of the unit.

Abstract: A method and apparatus is disclosed for securely attaching existing central aluminum or steel adaptors for air brake actuators to existing steel service brake housings, existing steel emergency brake housings, or both without major modification to either housing or the adaptor. An annular shoulder is provided in the steel brake housing, and the aluminum adaptor is provided with a small outwardly extending annular lip. A flexible diaphragm is sandwiched between the shoulder of the steel brake and the annular lip of the adaptor. One or more C-shaped retaining pieces are then placed around the sandwiched shoulder, diaphragm and lip. A weld is then applied to connect the C-shaped steel piece to the steel-housing, thereby holding the aluminum or steel adaptor and diaphragm securely in place.

Abstract: A method and apparatus is disclosed for securely attaching existing conventional central adaptors for air brake actuators to service brake housings, emergency brake housings, or both, that are made from a metal that is dissimilar to that of the adaptor without major modification to either the housing or the adaptor. An annular shoulder with an elongated annular flange above it is provided on the steel part, and the aluminum part is provided with a small outwardly extending annular lip. A flexible diaphragm is first placed directly on the shoulder of the selected steel part. The aluminum part is then placed on top of the diaphragm such that the annular lip of the aluminum part fits inside the annular flange of the steel part. A slightly deformable annular steel piece is placed around the aluminum part so that it comes to rest against the annular aluminum lip while also touching the annular steel flange of the steel part.

Abstract: A method and apparatus is disclosed for securely attaching existing central aluminum or steel adaptors for air brake actuators to existing steel service brake housings, existing steel emergency brake housings, or both without major modification to either housing or the adaptor. An annular shoulder with an elongated annular flange above it is provided in the steel brake housing, and the aluminum adaptor is provided with a small outwardly extending annular lip. A flexible diaphragm is first placed directly on the shoulder of the steel brake housing. The aluminum or steel adaptor is then placed on top of the diaphragm such that the annular lip of the adaptor fits inside the annular flange of the housing. A slightly deformable annular steel piece is then placed around the aluminum adaptor so that it comes to rest against the annular lip while also touching the annular steel flange of the housing. One or more breaks may be provided in the annular steel piece to facilitate placing it over the aluminum adaptor.