Improvements in Means for Opening and Closing, or Manipulating, Ventilators, Sashes, Doors, Shutters, or the like, which are in places not readily accessible

摘要

14,956. Walker, J. G. July 20. Plug and check valves. -In pneumatic window-operating apparatus, a hand-operated pump P is provided with a valve-box T having four passages which are governed by a plug cock V having therein two passages R, R'. Passages V1, V2 are controlled by valves F, F1 formed by cutting curved slits in a disk of indiarubber or the like. Specification No. 8852, A.D. 1896, [Abridgment Class Buildings &c.], is referred to.