| 摘要 |
528,242. Pneumatic single-stroke apparatus. YALE & TOWNE MANUFACTURING CO. Feb. 3, 1939, No. 3698. Convention date, Feb. 3, 1938. [Class 8 (ii)] [Also in Group XXV] A door closer of the kind comprising a spring 22 and a fluid chock 23 is adapted for opening the door against the resistance of the spring by admitting pressure fluid to the piston head 23 through a nipple 51 and piston valve 49 slidable in a ported sleeve 43, the fluid being exhausted through passages 57, 36 when the door is to be closed. The pressure fluid is supplied from a tank 62 through pipe 70, slide valve 71 and pipe 52, while the exhaust returns by pipe 39 to tank 41, from which it is forced by a pump 61 to tank 62 while at the same time air is forced into tank 62 by a cam-driven pump 66, 67. The motor 63 driving the pumps is energized by a mercury switch 63a controlled by a float 74, and the air pressure in tank 62 is controlled by a bellows device 77, 78. The valve 71 is controlled by an electromagnet 82 energized when a person approaching the door interrupts a light beam falling on a photo electric cell 88. In another form the cell 88 controls the energization of a motor driving a pump to supply the fluid to 23. In another form, the pressure fluid is supplied by a piston operated by the water pressure of an ordinary tap controlled by a rotatable valve, operated by the relay 82. |
