Patent GB-761432-A (GB)
Title: Improvements in or relating to locks
IPC: E05B37/08
Filed: 1952-06-06
Abstract: 761,432. Permutation locks. MILNERS SAFE CO., Ltd., and WHITEHEAD, F. May 28, 1953 [June 6, 1952], No. 14289/52. Class 44. A permutation lock including rotatable tumblers 16, Fig. 1, a driver wheel 29 for adjusting the tumblers and actuating the bolt 17, and a lever 19 pivoted to the bolt at 20 and having a fence 23 co-operating with gates 24 in the tumblers and a projection 22 co-operating with a driver wheel gate 31, is characterized by the provision of a guard element adapted to hold the lever 19 in a position in which the fence and projection are out of contact with the tumblers and driver-wheel respectively, but which is movable in a given direction to release the lever and when so moved to lock the drive wheel against rotation. The lock has a base 10 and cover-plate 11, the base having attached thereto, a hollow boss 15 carrying the tumblers 16, and through which passes a hollow driving-shaft 14 secured at its inner end to the drive wheel 29 and at its outer end to a knob 13 and dial 12 which co-operates with an escutcheon (not shown). The driver wheel has a lug 52 for driving the tumblers through a member 53 in known manner and the combination of the lock may be altered in known manner from a keyhole 56 in the cover 11 and members 55 in the tumblers. The guard element includes a disc 33 slightly larger in diameter than the wheel 29 and having a gate 36 corresponding substantially with the shape of the gate 31. This disc is non-rotatable relative to the driver wheel but can slide axially by means of pins 37 in the driver wheel engaging holes 38 in the disc 33. Fixed to the disc 33 is another disc 39 of the guard element provided with holes 40 to slidably engage the pins 37. Mounted for transverse sliding movement on the disc 39 is a closure member 44 provided with a pin engaging in a slot 46 in the disc 39. This closure member normally fits in the gate 36 so as to complete the circular periphery of the disc 33, and is urged. to this position by a spring 47 mounted on the disc 39. A space 48, Fig. 2, formed in the disc 33 between the inner end of the member 44 and the inner end of the gate 36 is adapted, as will be described later, to receive a pin 51 on the projection 22. The disc 33 is secured to a rod 32 passing through the driving- shaft 14 (see also Fig. 4) which rod at its outer end carries a push-button 34 and is urged outwardly of the knob 13 by a spring 34a. In the operative condition of the lock the disc 33 abuts the driver wheel 29 as shown in Fig. 4, and the pin 51 rides on the periphery of the disc 33 and the closure member 44 to hold the fence and projection 22 above the associated gates. To open the lock the tumblers are operated from the knob 13 in known manner to align the gates 24 below the fence 23. The knob is then rotated to align the gate 31 below the projection 22. At this instant a pin 49 on the disc 39 is aligned with an aperture 50 in the cover 11. If now the push-button 34 is depressed the discs 33, 39 will move to the position shown in Fig. 5, the pin 49 engaging in the aperture 50. The pin 51 is thus released from the peripheral surface of the closure member 44 and the projection 22 can drop into the gate 31. However, the driver wheel is now locked against rotation through the pins 37, discs 33, 39, pin 49 and aperture 50. In order to allow rotation of the driver wheel to operate the bolt, the pushbutton must be released, whereafter the disc 33 again abuts the driver wheel and the pin 51 is now enclosed in the recess 48, as shown in Fig. 2. When the knob 13 is now turned the bolt is retracted. At this stage the lever 19 coacts with a fixed stop 25 on the base 10 so that with the lock opened the fence 23 and projection 22 cannot be lifted out of their associated gates. On rotating the driver wheel clockwise , as seen in Fig. 2, the pin 51 contacts one end of the member 44 and since the lever at this stage cannot be raised owing to the stop 25, the lever 19 is moved to the right and the bolt to the locking position. Further rotation causes the member 44 to be displaced against its spring 47 and the lever 19 to be raised by the projection 22 moving along a face 54, Fig. 1, of the gate 31, Finally, the closure will snap back into the gate 36 and the pin 51 will again rest on the periphery of the closure member.