Means for lengthening or shortening an element such as a table leg

摘要

569,723. Door stops. DEAL SLIDE-LOCK DEVICES, Inc. April 9, 1943, No. 5741. Convention date, March 18, 1942. [Class 65 (i)] [Also in Groups XIV, XXX, and XXXII] Shortening or lengthening a support &c., or an equivalent adjustment as described in Specification 452,626 can be applied to a table leg, a door bolt, transom, window, chair, emergency brake for a car, &c., a microphone stand, photography screen, lamp tripod, car jack, &c., in which a pair of co-operating wedges 7, 8 slidable in a guide 2 is fixed on the table leg, the wedge 8 can be pulled out to form an extension of the table leg, the top wedge following it down by the pull of a spring connection 12 so that when weight is applied to the table the wedges in forcing themselves apart bind frictionally against the flanges 6 of the guide 2 and so prevent movement, the sloping faces of the wedges being prevented from binding frictionially by the interposition of a flexible strip wire or cable 11. To shorten the effective length of the table leg the upper wedge 7 requires to be moved up first, with 8 following it, this operation being more conveniently carried out by a knob 19 on a sliding plate 18 with a top and bottom slot 20 holding a screw 21 fitting into each wedge, so that up or down movement of the knob first forces the top or bottom wedge respectively from the other and then moves both wedges up or down together. Fig 8 is a bolt or latch for a door.