Antitheft device for lorry trailer with fifth wheel has key engaging cylinder lock which presses on brake application button which drains air out of pressure reservoir and allows spring to apply brake

摘要

The key (1) operates a cylinder lock (11) with a bolt (10) which may engage in a bore (9) in a lock housing. A steel housing (12) surrounds the lock and is riveted (7) to a web of the trailer frame (3). The lock can hold down a button (8) which releases air from the brake air reservoir. The button actuates a valve (5) on the other side of the frame web from the lock. The valve has two air connections (4,6). When the air pressure is released, a spring applies the brake. A further lock may prevent retraction of the prop used when the trailer is detached from the tractor vehicle.