Abstract: A sander includes a roller rotatably secured to a support, a bracket rotatably supported on the support at a pivot pin, another roller rotatably secured to the bracket, a sander belt engaged around the rollers. One of the rollers is rotated about the support for twisting the sander belt and for removing some of the dust from the sander belt. An actuator includes a rod engaged with the bracket for rotating the bracket about the support. A valve is coupled to the actuator for selectively supplying the air to the actuator via a rotatable spindle and a lever.

Abstract: A device for locking a vehicle and for preventing the vehicle from moving down a hill includes a housing secured to the vehicle and a beam rotatably secured in the housing. A casing is secured on top of the beam and a ball is received in the casing and has a tendency to move downward to the bottom of the casing for allowing the ball to maintaining the beam at a position perpendicular to the supporting ground. A ratchet mechanism may stop the wheels of the vehicle when the beam is tilted relative to the housing and when the housing is tilted relative to the supporting ground.