GB931308A - Improvements in or relating to releasable fastening devices - Google Patents

Abstract

931,308. Latches. WILMOT-BREEDEN Ltd. May 9. 1962 [May 17, 1961], No. 17931/61. Class 44. A latch mechanism comprises a latch cam 2, and a cam plate 6 mounted on a spindle 3 on opposed sides of a back plate 4, cam plate 6 bearing arms 7, 8, 9, arm 9 of which is attached to one end of a spring 5 to bias the latch into the operative position. The external release mechanism comprises slotted levers 12, 13 pivoted at 14 to the back plate 4, lever 12 bearing a flange 12a for engagement by a push-button, and an arm 15 which is connected to the other end of the spring 5. A spring-loaded locking lever 17 is pivoted at 18 to the back plate 4, one end 19 projecting through a slot 20 in a flange portion 46, to engage a link 22 which is connected to a sill button. Link 25 is connected to the end 26 of the locking lever 17 by a pin and slot means, and bears a pin 27 which extends through slots 28, 29 of the levers 12, 13 to connect them together to act as one lever. To lock the mechanism from the inside the link 25 is moved through lever 17 to a position where the pin 27 is adjacent the part 29b of the slot 29 whereupon, on depression of the push-button the pin 27 is moved along the slot 29b and the two levers are disconnected and the push button rendered ineffective to operate the latch mechanism. A " self-cancelling " arrangement to prevent the door being locked inadvertently when members 17, 22, 25 are in the locked position is arranged so that on slamming the door initial rotation of the latch cam 2 on engagement with the keeper, causes the limb 30 of the sill control link 22 to be engaged by a peg 33 of arm 8 so that the link 25 is moved into the position in Fig. 3 through sympathetic movement of lever 17. " Keyless " locking is effected by moving the sill control 22 to the locked position, and depressing the push-button before closure of the door to move the pin 27 along the slot 29b so that the link 25 is restrained against return to the normal position. The internal release mechanism comprises a pivoted bell-crank lever 32 bearing an arm 40 which engages the pin 33 of the arm 8. A keeper for the latch, Fig. 2 (not shown), comprises an upper guide member which engages in the closed position a yoke 47 of the cam 2, and a spring-loaded wedge which engages the guide plate 43. .