| 摘要 |
<p>477,549. Door-operating appliances. KERSHAW, A. G., LEECH, K. H., and WESTINGHOUSE BRAKE & SIGNAL CO., Ltd. July 3, 1936, No. 18517. [Class 65 (i)] A fluid-pressure door engine is controlled by an electromagnetically-operated valve with mechanical means for setting the valve into a neutral position to allow operation of the door by hand. In the form shown, the engine 1 comprises two cylinders with pistons connected by a rack bar 6 engaging a sector on the door-operating lever 9. The outer ends of the cylinders are connected by passages 12, 13 to a slide valve 17 by which they are alternately connected to the atmosphere and to a pipe 19 leading from a vacuum (or pressure) reservoir. The valve 17 is operated to either extreme position by electromagnets 21, 22 under the control of driver's switches 26 and a conductor's switch 38, and mechanical means are provided at 41 whereby passengers can move the valve 17 to a central position, thus opening both cylinders to the atmosphere so that the door is balanced and can be moved by hand. A number of doors in a vehicle or train may be controlled from the same switches.</p> |
