Abstract: A conveyor comprises an endless loop of linked wheeled chassis members running in a guide track. The chassis members are T-shaped with the wheels of each member being attached to the ends of the cross-member of the T. A carrier is releasably attached to each of the chassis members and electrical power is generated by a hub-mounted generator attached to at least one of the wheels of each chassis member. The carriers are preferably in the form of cross-belt units driven by a.c. motors on the carriers whereby items placed on the units can be discharged transversely of the direction of movement of the conveyor.

Abstract: An air gun for releasing compressed air into the environment. Two opposing shuttle valves selectively open ports to release compressed air more quickly from the air gun. A centering mechanism returns the first and second shuttle valves to the initial position. The centering mechanism can comprise a pressure compensation system or mechanical stop for positioning the first and second shuttles at the selected position.