GB1375714A - - Google Patents

Abstract

1375714 Locks G R PIEDDELOUP 19 Nov 1971 [26 Nov 1970] 53853/71 Heading E2A A locking mechanism comprises a plurality of toothed wheels 17 each of which is engaged by a pawl 21 each wheel having a plurality of angular positions in each of which a respective pawl will retain the wheel and in one of which the pawl releases a locking member 25 for displacement, the wheels being rotatable senatim by a multi position selector dial 1 to their release positions upon dialling a preset sequence of numerals or letters. The dial 1 is connected by a shaft 3 to a disc 8 which is retained by a pawl 9 swivelling on a spindle 11 which also supports the pawls 21 for the toothed wheels 17 freely pivoting on the shaft 3. The first toothed wheel is set by dialling the first numeral or letter of the code thereby turning the disc 8 together with a shaft 12 connected thereto and which engages in a recess in a slider 15 slidable longitudinally relatively to the shaft 3 and depressed by a stop 13 spring urged to engage an abutment on the slider, the slider being connected to the wheel 17 by a rod 20 which turns the wheel. The wheel is retained in the set position by the pawl 21 engaging in a shallower tooth of the wheel. Setting the wheel causes the rod 20 to disengage a recess in the next one of a series of the stops 13 which stop pivots anti clockwise under the pressure of a spring 13b, and depresses the next slider 15 against the pressure of a spring 15B so that the shaft 12 then engages in the recess of the slider when the next numeral or letter of the code is dialled. The abutment projecting from the first slider 15 disengages the first stop 13 which held the first slider 15 depressed, the rod 20 remains in driving position in the slot in the slider 15 under the action of a restoring spring 19 acting on a member 18 connected to the wheel 17 by the rod 20 until the wheel is set when spring 15B raises the slider 15 so that the recess therein is out of engagement with the shaft 12. When the second wheel is set the third slider 15 is depressed to engage the shaft 12 when the third numeral or letter of the code is dialled. By dialling the remaining numerals or letters of the code all the wheels 17 are set so that all the pawls engage in a shallower tooth of the respective wheels and the member 25 is in a releasing position in the L-shaped slots in the pawls. To restore the wheels to their original positions the member 25 is displaced in the slots in the pawls to pivot the pawls to release the wheels which return to their original positions under the action of the springs 19. The stops 13 reengage the rods 20 and are raised to inoperative position, the first stop remains depressed under spring action. The sliders 15 are restored to their original position. The code is changed by turning each wheel 17 a predetermined single relatively to the respective member 18 fixed to the shaft 3 and by inserting the rod 20 in the new aperture in the wheel.