Crimped sealed adapter bushing assembly for a double diaphragm spring brake actuator

A bushing assembly permitting a push rod to pass through an aperture in an adapter plate forming an outer wall of a pressure chamber, said bushing assembly comprising:

• a tubular sleeve having an outer surface and a cylindrical interior, the cylindrical interior being oriented about a longitudinal axis extending from a first end of the sleeve to a second end of the sleeve and having an associated interior diameter that is greater than a corresponding diameter of said adapter plate aperture, the first end of the sleeve being rigidly coupled to the adapter plate about a periphery of the aperture such that the cylindrical interior is generally aligned with the aperture and the longitudinal axis is generally perpendicular to the outer wall of the pressure chamber;
• a first circumferential stop rigidly coupled to the tubular sleeve and extending inwardly into said cylindrical interior at said first end of the tubular sleeve;
• a cylindrical bushing having a first end, a second end, an interior wall and an exterior wall, the first end of the bushing being retained within the cylindrical interior of the sleeve by the circumferential stop, the second end of the bushing being retained within the cylindrical interior of the sleeve by substantially inwardly deforming the sleeve adjacent of the second end of the sleeve, the interior wall of the bushing being adapted to directly receive and guide the push rod, the exterior wall of the bushing being in contact relationship with the cylindrical interior of the sleeve;
• a first sealing element disposed between the bushing and the push rod;
• and
• a second sealing element disposed between the adapter plate and the bushing.

A double diaphragm brake actuator, comprising:

• a spring brake actuator comprising a push rod and a first pressure chamber;
• a service brake actuator comprising a second pressure chamber;
• an adapter plate for coupling the spring brake actuator to the service brake actuator, said adapter plate forming a shared wall between the first pressure chamber and the second pressure chamber and defining an aperture for allowing the push rod to pass through from the first pressure chamber to the second pressure chamber;
• and
• a bushing assembly for facilitating passage of the push rod through the aperture in the adapter while maintaining a fluid tight seal between the first pressure chamber and the second pressure chamber, said bushing assembly including
• a tubular sleeve having an outer surface and a cylindrical interior oriented about a longitudinal axis extending from a first end of the sleeve to a second end of the sleeve, the first end of the sleeve being welded to the adapter plate such that the cylindrical interior is generally aligned with the aperture and the longitudinal axis is generally perpendicular to the shared wall;
• a circumferential stop rigidly coupled to the tubular sleeve and extending inwardly into said cylindrical interior at said first end of the tubular sleeve;
• a cylindrical bushing having a first end, a second end, an interior wall and an exterior wall, the first end of the bushing being retained within the cylindrical interior of the sleeve by the circumferential stop, the second end of the bushing being retained within the cylindrical interior of the sleeve by substantially inwardly deforming the sleeve adjacent of the second end of the sleeve, the interior wall of the bushing being adapted to directly receive and guide the push rod, the exterior wall of the bushing being in contact relationship with the cylindrical interior of the sleeve as said push rod cycles back and forth;
• a first sealing element disposed between the bushing and the push rod;
• and
• a second sealing element disposed between the shared wall and the bushing.

A double diaphragm brake actuator, comprising:

• a spring brake actuator comprising a push rod and a first pressure chamber;
• a service brake actuator comprising a second pressure chamber;
• an adapter plate for coupling the spring brake actuator to the service brake actuator, said adapter plate forming a shared wall between the first pressure chamber and the second pressure chamber and defining an aperture for allowing the push rod to pass through from the first pressure chamber to the second pressure chamber;
• and
• a bushing assembly for facilitating passage of the push rod through the aperture in the adapter while maintaining a fluid tight seal between the first pressure chamber and the second pressure chamber, said bushing assembly including
• a tubular sleeve having an outer surface and a cylindrical interior oriented about a longitudinal axis extending from a first end of the sleeve to a second end of the sleeve and having an associated interior diameter that is greater than a corresponding diameter of said adapter plate aperture, the first end of the sleeve being rigidly coupled to the adapter plate about the adapter plate aperture such that the cylindrical interior is generally aligned with the aperture and the longitudinal axis is generally perpendicular to said shared wall;
• a circumferential stop rigidly coupled to the tubular sleeve and extending inwardly into said cylindrical interior at said first end of the tubular sleeve;
• a cylindrical bushing having a first end, a second end, an interior wall and an exterior wall, the first end of the bushing being retained within the cylindrical interior of the sleeve by the circumferential stop, the second end of the bushing being retained within the cylindrical interior of the sleeve by substantially inwardly deforming the sleeve adjacent of the second end of the sleeve, the interior wall of the bushing being adapted to directly receive and guide the push rod, the exterior wall of the bushing being in contact relationship with the cylindrical interior of the sleeve as said push rod cycles back and forth;
• a first sealing element disposed between the bushing and the push rod;
• and
• a second sealing element disposed between the shared wall and the bushing.