Patent ID: 8522666

Claim:
A brake actuator comprising: a first housing part having a centerline, a first generally cylindrical chamber sidewall, a portion of which defines a first cylindrical profile having an inner surface contacted by a working fluid inside said housing part, and a first circular contact surface, wherein said first generally cylindrical chamber sidewall terminates in an annular edge and the first contact surface is devoid of a sharp edge and is located on an entirety of the annular edge of said first sidewall: b) a second housing part having a centerline in axial alignment with the centerline of said first housing part, a second generally cylindrical chamber sidewall, a portion of which defines a second cylindrical profile haying an inner surface contacted by a working fluid inside said housing part, and an annular knuckle provided on said second generally cylindrical sidewall with a second circular contact surface that is devoid of a sharp edge on said knuckle, said second contact surface being in alignment with said first contact surface and extending around said centerline; and c) a flexible diaphragm having a peripheral edge, said diaphragm being axially compressed near said peripheral edge between the first contact surface and the second contact surface: wherein said first and second housing parts form a chamber that encloses a spring assembly, wherein the direction of said axial compression is substantially parallel to said centerline, and wherein the peripheral edge of said diaphragm does not extend radially beyond at least one of said first cylindrical profile and said second cylindrical profile.