GB815654A - Improvements in and relating to permutation locks - Google Patents

Abstract

815,654. Permutation locks. CHUBB & SON'S LOCK & SAFE CO. Ltd. Feb. 11, 1957 [May 4, 1956], No. 13910/56. Class 44 In a permutation lock comprising a driver 8 adapted to be engaged by a fence lever 4 so as to withdraw a bolt 3, snapaction strip spring means are provided which move between a position in which the fence lever is restrained from engaging the driver, and a position in which the fence lever is free to engage the driver. As described, the strip spring means (see Figs 5 and 6), is E-shaped, the centre limb 13 being longer than the outer limbs 14 and having a T piece 15 which engages a recess 17 in a substantially L-shaped plate 12. The centre limb lies in a slot 16 extending from the recess, and the extremities of the limbs 14 engage grooves in the plate edge on either side of the slot 16, the relative length of the limbs being such that the outer limbs 14 are bowed, as in Fig. 6. Stops 18, 19 limit the movement of the spring means which normally lie adjacent the stop 18, as in Fig. 6, with an abutment 20 formed on the bridge of the E-shape engaging a chamfered edge 22 on the fence lever 4 which is thus held out of engagement with the driver 8. Axial movement of the shaft 7 causes an abutment 23 formed on the rear face of the driver 8 to engage the limb 13 of the strip spring which is thereby snapped into engagement with the stop 19 permitting the lever 4 to drop into engagement with the notch 9 of the driver. Axial movement of the shaft 7 to its original position disengages the abutment 23 from the limb 13 thus enabling the strip spring to snap back into a position where the nose of the abutment 20 engages the side of the lever 4. Rotation of the operating knob to disengage the lever 4 from the driver 8 brings the chamfered part 22 adjacent the projection 20 which thus causes the lever to move wholly out of engagement with the driver. The correct angular position of the driver to bring the abutment 23 adjacent the limb 13 is indicated by a reference mark on the lock face. A semi-circular ridge on the rear plate of the lock in conjunction with abutments 25 on the driver prevents axial displacement of the shaft unless the driver is correctly positioned, and prevents rotation of the shaft when so displaced. An anti-picking device comprises a stud on the rear plate which passes through a hole 28 in the plate 12 and holds a spring-urged dog out of engagement with the bolt. Removal of the rear plate releases the dog which then engages the bolt to hold it in the locked position. Specifications 705,729, 735,148, 748,360, 761,432 and 763,597 are referred to.