Patent GB-233085-A (GB)
Abstract: 233,085. Hoffman, A. Feb. 28, 1924. Locks requiring complex movement of key; hasp locks; loc, k mechanism, tumbler type; spring tumbler type; twobolt locks; keyhole curtains. - A lock particularly suitable to trunks or doors has a pair of sliding bolts released and operated by complex movement of a kev with pivoted hook between them which can be operated by the final movement of the key or by a knob turned by hand. Fig. 3 shows the lock in the locked condition, fingers 120 on upper and lower sliding plates 96 constituting the sliding locking bolts engaging keepers 17, 19 on the striking plate 22 on the door jamb, and a central hook 77 pivoted at 29 to the casing engaging a central keeper 18. To unlock, the key 118, Fig. 8, is inserted into the upper keyhole in the exterior plate on the door 10 and pushed through a hole in the top plate 23, Figs. 2 and 6 until the bit 119 is clear. It is then turned clockwise until the bit is aligned with the slot 48 in the top plate and pulled upwards, when the bit engages the end of a leaf spring 50 and lifts a pin 49 out of a slot in the foot flange 36 of the upper key socket and also lifts the pin 55 on the spring 50 out of a hole 114 in a dog 104 pivoted at 103 to the upper plate 96. The key is then moved upwards until the bit is clear of the plate 23 and is engaging in the slot in the flange 36 which is now free to be turned against its spring 64. The key is turned clockwise, rotating the flange 36 so that the depression 124 therein comes over the finger 75 of the sliding member 57 which is pulled upwards by the spring 66 to release its shoulder 73 from that 74 of the foot flange 37 of the lower key socket, releasing this for turning against its spring 69. :The key is then withdrawn and inserted into.the lower key socket until its bit is engaging the slot in the lower foot flange 37 and is turned anti-clockwise, moving the flange so that the bevel 46 thereon lifts the plate spring 54 to withdraw a pin 56 thereon from a hole 114 in the lower dog 104. The key is then withdrawn and re-inserted in the upper key-socket beyond the plate 23 and turned anti-clockwise. It engages a tumbler 89 pivoted to the casing at 90 and moves it against its spring to free its notch 94 from the stump 128 in the upper bolt plate 96, Fig. 3. Also the dog 104, having had the pin 55 freed from its slot 114, has been pressed towards the key-pin 116 by a spring so that while rotating the key bit also engages the inclined face 129 thereon and moves the dog, and consequently the plate 96 to which it is pivoted, a small distance in the direction of withdrawal, until the key bit is clear of the face 129. This brings the pawl 108<1> which is pivoted at 109 on the plate 96, within range of the key bit, so that on continuing the rotation of the key in an anticlockwise direction, it engages the pawl 108<1> and effects the complete withdrawal of the plate 96, freeing the finger 120 from the keeper 19. The plate 96 is withdrawn in the same manner, each complete turn of the key lifting the block 79 pivoted to the end 76 of the hook 77 and allowing it to fall again to re-engage the hook. When the lower plate 96 is fully withdrawn so that the finger 102 is clear of the keeper 17, a final turn of the key releases the hook 77 from the keeper 18 and the door can be opened. The hook 77 may be independently operated by an inside handle 86 which can turn a follower 84 to lift the block 79. The follower 84 may be left in the vertical position so that the hook 77 is clear of the keeper 18 until the follower is turned back again. Fig. 9 illustrates a modification wherein the pins 49, 55, 56 on the plate springs 50, 54, Fig. 2, connected by a piece riveted to the side wall of the casing, are replaced by pins 132, 133, 134 on a single plate spring 130 screwed to the plate 23 at 131.