Patent GB-1214823-A (GB)
Title: Combination lock
IPC: E05B37/14
Filed: 1967-11-13
Abstract: 1,214,823. Combination locks. J. E. MEAGHER, G. KARADEDIAIN, J. B. PECEL and L. PECEL [trading as KAPP]. 13 Nov., 1967, No. 51606/67. Heading E2A. A combination lock comprises a body 20, an axle 37 mounted within the said body for rotation and axial shift, an actuating knob 27 for rotating and axially shifting said axle relative to said body, a pivotally mounted latch 26 and a plurality of combination tumblers 31 mounted on a carrier plate 30 in angularly spaced relationship around the axis of the axle, the said carrier plate being axially movable relative to the axle and the body for operative association with the said latch, having means (not shown) which normally prevents unlatching movement of the latch and being keyed against angular displacement relative to said body, an axially immovable support plate 33 being rotatably mounted in said body in coaxial relationship with the carrier plate, and a plurality of blocking elements 34 being carried on said support plate in angularly spaced relationship around the axle and being individually shiftable radially of the support plate between inner and outer positions; the said lock further comprising a block-carrying plate 76 coaxially rigidly secured to the axle for rotation and axial shift therewith, a plurality of. ramp blocks 77 rigidly secured to the said last-mentioned plate and projecting towards the support plate for the translation to the radially outer positions. of all those of the said blocking elements that are disposed in radially inner positions upon axial movement of the block carrying plate towards the support plate and actuating means operable by rotation of the knob and axle for sequentially and selectively moving individual blocking elements to the radially inner positions on said support plate after the blocking elements are all in their radially outer positions, whereby to dispose the said blocking elements in positions such that the carrier plate with the combination tumblers can be moved to opposite axial movement of the knob on the axle to release the latch via release means carried by said plate. In the construction shown the lock is a padlock and the latch engages a notch in a short leg 25 of the padlock shackle to fasten the shackle to the body. The latch is pivoted in the body. The tumblers are each mounted on the carrier plate 30 for angular movement between two positions, one position allows movement of the combination means assuming that the other tumblers are in the correct positions when the corresponding blocking element is in the inner position, and the other position allows movement of the combination means when the corresponding blocking element is in the outer position. Each tumbler is formed with a pair of slots 61 spaced on opposite sides of the axis of symmetry of the tumbler and a locking plate 32 is provided which includes a plurality of tabs 62 one for each tumbler each tab being engageable with one or other of the slots of its corresponding tumbler to hold the tumbler in the desired position. The plate 32 is angularly adjustable relative to the carrier plate 30 to enable the tabs to be inserted into or withdrawn from the slots 61. A needle-like instrument is used for moving the plate 32 to withdraw the tabs 62 from their slots and to restore the plate 32 to the fastening position. To enable the instrument to be inserted into the casing an opening 106 is provided which is closed when the shackle is in the locked condition since the end portion of the long leg 24 of the shackle carries a blocking member 110 Fig. 4. When the shackle is unlocked and the leg 24 moved axially, the opening 106 is freed and the instrument is inserted through it to engage a hole that is formed in a tab projecting radially from the plate 32. This frees each of the tumblers for angular movement and by arranging the blocking elements in a desired combination and pressing the knob 27 the tumblers are forced against the blocking elements and moved to an appropriate positions after which release of the knob 27 causes the combination means to move back to its original position and the instrument is then used to rotate the plate 32 to fasten the tumblers in their new positions. In the construction shown the blocking elements are balls and the support plate 33 has eight equally angularly spaced and radially extending slots 80 (Fig. 8) one for each of the blocking balls, to provide a track for the ball. A spring disc 35 is provided which similarly is provided with eight slots, one for each ball, and the balls are trapped between such slots and the slots 80. The ramp elements 77 always project into the slots 80 so that the plate 33 rotates with the plate 76 when the knob is turned. Pulling on the knob causes the plate 77 to move closer to the plate 33 and the ramp elements to move further into the slots 80 and into the slots in the disc 35. Such movement moves any of the balls which are in the inner position to the outer position so that all the balls are positioned in the outer positions by such pulling on the knob. The actuating means for moving any desired ball 34 to the inner position consists of an L-shaped plate 95 Fig. 8 a pawl 96 pivotally connected to the rear face of the plate 95 and a generally S-shaped leaf spring 98, one end portion of which is fastened to the plate 95 and the other end portion of which biasses the pawl into engagement with the periphery of the ball support plate 33. In the position shown in Fig. 8 a shoulder 100 of the pawl is in engagement with an edge of one of the slots 80 in the plate 33 and rotation of the plate 33 counterclockwise by means of the knob moves the plate 95 downwardly and ramp edge 103 of the plate 95 engages the ball in the next slot to move it from the outer position to the inner position; clockwise movement of the plate 33 by the knob then restores the plate 95 to its original position, the strength of the spring 98 being such that the shoulder 100 of the pawl cannot escape from the engaged slot 80 during this movement; further clockwise movement of the plate 33 causes the opposite edge of the slot 80 to that engaged by the shoulder 100, to engage a cam edge 104 of the pawl and to pivot the pawl out of the way against the force of the spring 98 until another slot 80 is halted by a detent spring (not shown) which acts to position the plate 33 into desired angular position; thus by clockwise positioning of the plate 33 the required ball 34 is positioned in engagement with the ramp edge 103; counterclockwise movement of plate 33 moves the ball to the inner position and subsequent clockwise movement selects the next ball to be moved.