735,148. Permutation locks. CHUBB & SON'S LOCK & SAFE CO., Ltd. April 26, 1954 [June 19, 1953; Aug. 11, 1953; Sept. 10, 1953; Jan. 6, 1954], Nos. 17003/53, 22132 /53, 25049/53 and 407/54. Class 44. A permutation lock of the kind incorporating a bolt, a driver, a connecting lever pivoted to the bolt and engageable with the driver in order that the bolt may be operated by the driver and settable control means adapted, unless and until preset in a pre-arranged manner to restrain the connecting lever from engagement with the driver, comprises operable snap-action means for controlling movement of the connecting lever from a position of disengagement, towards a position of engagement, with the driver and into engagement therewith if the settable control means are correctly preset for that result. In the arrangement according to Figs. 2 and 6 of the first Provisional Specification, in which a bolt 11 is movable by means of a spring-loaded lever 12 having a hook 13 engageable with a recess in a driver 8 when a projection on the lever engages in aligned slots 10 in a plurality of wheels 9, a lever 16 pivoted on a plate 15 on the lower edge of a lock casing 1 projects at its upper end under a roller 17 secured to the rear face of the lever 12 to hold the latter from engagement with the driver 8, when the lever 16 is thrown about its pivot to the position shown in Fig. 2. The lower part of lever 16 is U-shaped to provide front and rear pivot pins and is loaded by a spring 22 connected between the lever 16 and a plate 19 pivoted to the upper edge of the casing 1 and carrying a pin 20 projecting through a slot 21 on the plate 15. Angular movement of lever 16 is limited by the sides of a recess in the plate 15 in which the lever is located. Cam surfaces 23, 24 on the plate 19 are engageable with pins 25, 26 on the driver 8 whereby rotation of driver 8 counter-clockwise from the position of Fig. 2 engages pin 26 with surface 24 to move the pin 20 and spring 22 to the other end of the slot 21 and swing the lever 16 away from roller 17, thus freeing the lever 12 for engagement with the driver 8. Clockwise rotation of driver 8 engages the pin 25 with surface 23 to swing the lever 16 back to the position shown. A spindle 3, to which the driver 8 is attached is normally spring-urged outwardly of the lock, in which position the pins 25, 26 are not in alignment with plate 19 and the spindle may be freely rotated to set the wheels 9. A pin 28 on the driver 8, which cannot contact plate 19, bears against a plate 30 on a rear coverplate 29 of the casing 1. A slot 31, in the cover 29 and plate 30 is formed with an enlarged end portion which permits entry of the pin 28 and inward movement and limited rotation of the spindle 3 and driver 8, a reduced neck portion of the pin then engaging the narrower portion of the slot 31 and the spindle 3 being held retracted by the head of the pin 28. The edge of the driver is stepped or flanged so that upon limited rotation of the spindle permitted by the slot 31, the hook 13 of the lever 12 rides against the flange, if the lever 16 is displaced to free the lever 12, unless and until the driver is pushed to its rearmost position, and allows the hook 13 to fall in front of the flange. A spring strip, Fig. 8 (not shown) with a bentover T-shaped head upstanding from the bottom of the lock casing engages an abutment on the rear cover thereof. If the cover 29 is removed the spring strip is released whereupon its head engages the lever 16 to maintain the latter beneath the lever 12. In another arrangement, Fig. 1 of the second Provisional Specification, a lever 16 pivoted to a plate 40 at the bottom of the lock casing 1 is controlled by a spring- loaded lever 41 pivoted at 18 and having a pin 20 projecting through the plate 40. Movement of lever 41 is effected by a pin 26 on a driver 8, adapted as the driver is rotated to ride against a cam edge 42 of lever 41. The arrangement is such that the lever 41 operates to return the lever 16 to its uppermost supporting position after the pin 26 has passed the cam edge 42, the lever 16 engaging the roller 17 on lever 12 from above if slots 10 in the wheels 9 have been aligned to permit the lever 12 to fall. If the slots have not been previously aligned, the roller 17 remains above the lever 16 which rides beneath the roller to lift the lever 12 to its uppermost position. In its forward position, the spindle 3 is out of alignment with the cam edge 42, whereby the driver 8 may be rotated to set the wheels 9. Rotation of the driver 8 when the spindle is pushed inwards is limited by a rib on the rear coverplate of the lock aligned with the pin 26 with which it abuts, the inward movement of the spindle being limited to a cut-away section of the rib. A spring strip may be attached to one casing side and arranged to co-operate with an abutment on the cover plate so that upon removal of the latter the spring engages the underside of lever 12 to hold the lever away from the wheels 9 and driver 8. Alternatively or additionally " dogging " means may be employed to prevent withdrawal of the lock bolt if the casing thereof is tampered with. As shown, Figs. 1 and 3 of the fourth Provisional Specification, a plate 102 secured to the lock casing 1, carries a V-shaped bracket 103 forming a pivot for a lever 104, one end of which is provided with a turned back lug 106 extending beneath the lock bolt 11. A pin 107 on the lug 106 aligns with an aperture in the bolt when the latter is in locking position. The other extremity of the lever 104 is formed with a lug 108 which normally abuts a pin 110 on a coverplate 29 to maintain the pin 107 disengaged from the bolt aperture. A spring- loaded cam member 111 is depressed by the lug 106 when the pin 107 is disengaged from the bolt, but removal of the coverplate causes the cam to rock the lever 104 and the pin 107 to dead-lock the bolt. The cam 111 is thrown beyond top dead centre so that it cannot be depressed again by merely rocking the lever 104. The cam 111 and adjacent parts are enclosed by an internal casing wall 114 to prevent unauthorised interference with the cam. A block 115 may be provided on the casing wall to support the pin 110. Specification 705,729 is referred to.