GB542299A - Improvements relating to door and like fastenings - Google Patents

Abstract

542,299. Door fastenings. LINES, A. Dec. 18, 1940, No. 17810. [Class 44] A lock particularly for the inner doors of houses has a key on each face of the door, the keys being permanently retained in the lock to prevent loss, and the lock mechanism arranged so that when the bolt is shot by either key, the other key is rendered inoperative. As shown, the bolt lath 1 has a lever 2 pivoted thereto at 3 and is cut away at 4 to allow upward movement of the lever. The lever is normally depressed by spring 6 against a fixed pin 5, is shaped to provide a pair of opposed shoulders 10, 13 and has a depending projection 7 adapted to engage the right or left side of pin 5 to lock the bolt. The two keys have their stems 8 in alignment and their bits normally in the position 16. The lever is wide enough to co-operate with both bits, and the bolt carries a projection 12 of similar width. In Fig. 2 the near bit 9 has been rotated anti-clockwise to shoot the bolt by co-operation with shoulder 10 after lifting the lever to move projection 7 clear of pin 5, and the lever has dropped to engage projection 7 to the left of pin 5 to lock the bolt in shot position. Rotation of the bit 9 is also arrested by pin 5. With the bolt thus shot, anticlockwise rotation of the other bit is arrested by projection 12, whilst pin 5 arrests clockwise rotation. A similar action occurs when the bolt is shot by bit 11, bit 9 being rendered inoperative. The bolt can therefore be retracted only by the key which shot it, its bit first lifting the lever to release projection 7 and then engaging shoulder 13. With a mortise lock as shown, the keys may be retained by forming the lock with keyholes 14 having horizontal extensions 15 to accommodate the key stems 8, the hole 14 being out of register with the position 16 of the keyhole in the door style. The lock is pushed into place till slots 14 register with 16, the keys are inserted, and the look pushed home to the final out of register position, the stems 8 passing along slot 15. To steady the motion of the key a plate 17 having a tubular bearing 18 for stem 8 is applied to the key before the bow 19 is secured to the stem. When the keys are in place, plates 17 are secured to the door by screws. With a rim lock, the casing may have circular holes through which the key-stems are passed from inside, the key bows being afterwards secured on the stems. Specification 502,369 is referred to.