Patent GB-1419831-A (GB)
Title: Door latches
IPC: E05B41/00
Filed: 1973-03-12
Abstract: 1419831 Door fastenings DAEMPA A/S 12 March 1973 [20 March 1972] 11741/73 Heading E2A A door latch comprises a bolt 12 that is spring loaded into its striker engaging position for fastening the door and at least one handle grip including an elongated housing 5 to be secured to the door in a substantially vertical position and carrying a press-button 6 that is operatively connected to the bolt so as to retract the bolt from its door fastening position to a door releasing position by a downwardly directed displacement of the press-button from its normal position of rest in relation to the housing. There is a second bolt operating means provided to prevent retraction of the bolt from its striker engaging position by the press-button and at the same time to displace the press-button out of its normal position relative to the housing to provide a visual indication of the inoperativeness of the press-button. As shown, a follower 9 has an inclined slot 10 so that when the cross-bar 8 is displaced vertically through guide slots 11 in the bolt casing 3 the follower is retracted against the pressure of a spring 13. The follower or bolt is further displaced forwardly by a pawl 15 acting on the follower and mounted on a lock shaft 14 turned by a separate key-operated hand grip; the push-button 6 becomes hidden inside the housing 5. In modifications, (a) the cross-bar 8 is horizontally displaceable by a pivoted lever 17, Fig. 5, a stop 20 being movable downwardly from the path of the lever whereby the lever is moved by a spring 19 so that the top of the lever passes the edge 23 of the push-button after which the latter moves downwardly to a position inside the tube; unlocking of the door is effected by upward movement of the stop whereby the lever, due to abutment with the face 22 of the push-button, forces the latter upwardly to its normal position, (b) the cross-bar 8 is rotated to operate a crank mechanism, Figs. 6 to 9 (not shown) the connecting rod of which moves past a horizontal dead centre position to place the bolt in a locked position, (c) the bolt casing 3 consists of two parts 3', 3" Fig. 10, connected by a pin 30. the part 3" being rotatable about its axis with respect to the stationary part 3' whereby the lock may be used for right and left-hand doors; the bolt 12 has a socket for a ball head 31 on the connecting rod 29, (d) the lower end of the push button plate 7 is provided with cam surfaces which operate respectively on the crank mechanism of the cross-bar 8 to withdraw the bolt and to maintain the bolt in a locked position, a stop (34), Fig. 16, (not shown) being fitted in the bolt casing to prevent backward displacement of the bolt from its locked position, (e) the cross-bar 8, Fig. 17, forms a crankshaft having crank throws 25, 26 connected by rods 35, to pressbuttons 6 and a crank throw 28 connected by a rod 29 to the bolt, rotation of a knob 36 secured to the cross-bar causing the bolt to be moved from its normal fastening position and to a locking position wherein the cranks 25, 26 assume a vertical position and the push-buttons are disolaced upwardly to disclose an indicator 37 to show that the door is locked.