Early Prison Cell Door Mechanism Salesman's Sample or Patent Model. Late 19th?early 20th century. Salesman's sample or patent model demonstrating a remote, two story, double door locking mechanism for jail cells. Contained within a dark wooden housing with brass fittings, lead[?] weights, steel and iron doors, a small glass window, and a leather carrying handle. There are four cabinet doors to view and adjust the internal mechanism. The model works by pressing one or two buttons to release a spring-loaded, weighted pulley system which closes cell doors one at time or in tandem. 16 ? x 10 x 7". One of the mechanisms needs repair (string broken), but the full functionality of the model can still be observed. RARE.