US Patent 7392887 Bladder actuator for a railroad retarder

The present invention pertains to a low-maintenance bladder actuator for a low-profile railroad retarder. The actuator has an internal guide mechanism and internal limit stops. The guide mechanism has a concentric, telescoping guide rod and guide sleeve that are removably bolted to upper and lower plates. An integral cast head forms the upper plate and a stop sleeve that absorbs the cyclical 20,000 pound loads of the actuator. This enables the guide rod to remain concentricly aligned. The guide mechanism has sufficient stroke length (SL) and includes a long internal bushing with a low wear rate. The stop sleeve engages the lower plate to form the lower limit stop. The stop sleeve includes an inwardly extending flange that engages an outwardly extending flange of the guide sleeve to form an upper limit stop. The stop sleeve and guide sleeve form a cam lock connection for easy assembly.