Patent GB-763597-A (GB)
Title: Improvements in or relating to combination locks
IPC: E05B37/08
Filed: 1953-05-02
Abstract: 763,597. Combination locks. MILLER, H. C. May 2, 1953, No. 12213/53. Class 44. In a combination lock of the type comprising a plurality of gated tumblers, a gated driver wheel which operates the tumblers, a fence mounted on a fence lever pivoted for movement towards and away from the tumblers and driver wheel and adapted to drop into the gates of the tumblers when these are aligned and the driver wheel manipulated to position its gate to receive a depending boss on the fence lever, means are provided to support the driver wheel for axial movement and means are also provided to normally engage the fence lever and support the boss and fence out of engagement with the driver wheel gate and tumblers during adjustment of the latter, and movable, by axial shifting of the driver wheel, following operation of the tumblers to permit interdigitating of the lever boss in the driver wheel gate and the fence in the aligned tumbler gates. As shown in Fig. 1, tumblers 16, 17, 18, of known two-part construction facilitating the changing of the combination, are freely mounted on a hollow boss 11a integral with the lock casing 11 and are drivable in known manner from the driver wheel 22 secured to a spindle 21 passing through the boss 11a and a door 13 and rotatable by a dial 23 co-operating with an indexed escutcheon plate 19. The dial, shaft and wheel 22 can be moved axially inwardly of the casing 11 against the action of a spring 53, as will later be described. A known anti-tampering device in the form of a lever 41 pivoted at 43 in the casing, is also provided, which can effect the release of a spring-loaded pin 44, Fig. 2, to engage in a recess in the bolt 33 and positively lock it. The fence-lever 34, Fig. 2, is pivoted at 36 to the bolt 33 and is under the urge of a spring 40. The fence 37 extends from lever 34 and cooperates with gates 16a, 17a, 18a in the tumblers when aligned. A shaped boss 38 on the lever 34 co-operates with the complementary shaped gate 22a of the wheel 22. The lever 34 is normally held in a raised position so that the fence 37 and boss 38 are out of contact with the tumblers and wheel 22, by the curved end 52, of a leaf-spring 50, engaging under the boss, the spring 50 being secured to the casing 11 at 51. When raised the fence 37 has a clearance above the tumblers which is less than the clearance between the boss 38 and wheel 22 so that if the fence should drop before the gates 16a, 17a, 18a are aligned the boss will not contact the wheel 22. In operation the tumbler gates are aligned by rotating the wheel 22, first clockwise, then counterclockwise, and then again clockwise, from the dial 23 in known manner according to the particular combination. The dial 23 is then rotated counterclockwise to a preselected index on the plate 19. A T-shaped stud 55, Figs. 1 and 2, projecting from the wheel 22, is then aligned with a complementary slot 56a in the casing cover 11b, which slot is at the end of an arcuate slot 56 in the cover 11b, of a width corresponding to the neck of the T-shaped stud. Referring to Fig. 3, if the shaft 21 and wheel 22 are now moved axially the stud 65 will pass through the slot 56a and allow the wheel 22 to engage the spring-end 52 to release the lever 34. The fence will then commence to enter the aligned tumbler slots and the boss 38 can then engage the periphery of the wheel 22. On rotating the wheel the neck of the stud 55 passes along the slot 56, the wheel 22 then being locked against axial movement and the drive between it and the tumbler 18 is disconnected. Within the limits of this slot the boss 37 drops into the gate 22a to cause, in the last movement of the wheel 22, the bolt 33 to be retracted. The peripheries of the tumblers and the bottom of the fence are serrated as at 60, 61, Fig. 2, respectively, so that the parts will lock, if the fence should drop before the tumbler gates are aligned, with the boss 38 out of contact with the wheel 22. It is, therefore, impossible under these conditions to vibrate or walk the tumblers in an attempt to open the lock. In a modification a vertically disposed spring has its turned end normally engaging under a projecting leg of the fence-lever and the leg is released on axial movement of the driver wheel. In a further modification the fence lever is normally held raised by engaging one arm of a spring- urged bell-crank pivoted to the casing cover, the other arm engaging the face of the driver wheel. A cylindrical stud projects from the face of the driver wheel in lieu of the previously mentioned T-head and this cylindrical stud can engage in a cut-away portion in an annular boss on the inside of the casing cover. The embodiment of Figs. 8 and 9 differs from the previous embodiments in that, the fence-lever 79 has two arms 80, 81 and is pivoted on a pin 79<SP>1</SP> secured to the casing 11; the bolt 75 has an integral plate extension 76 slotted at 76<SP>1</SP> to bear on a fixed sleeve 77, so as to be slidable rectilinearly, and a spring 86 urges the dial 23 towards the escutcheon plate. The arm 81 is under the influence of a spring-urged pin 82 carried in the bolt 75 whilst the main portion of the arm 80 comprises the fence engageable with the tumbler gates. The arm 80 has an end lip 80<SP>1</SP> which can cooperate with a gate 85a in a driver wheel 85 and a lateral projection 80<SP>11</SP> which engages the means for normally holding the lever 79 away from the tumblers and driving wheel. An L-shaped slot 88, 881, of which the portion 88 is arcuate, is provided in the wheel 85 and can co-operate with an L-shaped lug 87 fixed to the casing. The lever holding means comprises a pin 93 slidably mounted in the casing and urged by a spring 94 towards a cylindrical member 90 secured to the spindle 21. The outer end of the pin abuts the projection 80<SP>11</SP>. A chamfer 90<SP>1</SP> is provided on the member 90 so that when the dial 23 and shaft 21 are pulled outwardly against the spring 86, the pin 93 can move inwardly to release the lever 79. During such axial movement of the wheel 85 the head of the stud 87 must be aligned with the portion 881 of the driver wheel slot. After the tumbler gates have been aligned in known manner and the slot and lug subsequently aligned, the wheel 85 is pushed back so that the pin 93 releases the lever 79 and the fence can commence to enter the tumbler slots. During later movement of the wheel within the limits of the slot the lip 801 engages the gate 85a and continued turning of the wheel causes the arm 81 to abut a lug 83 on the bolt extension plate 76 and thus retract the bolt. Specification 651,187 is referred to.