Patent GB-681236-A (GB)
Title: Improvements in lock or latch mechanisms
IPC: E05B35/00
Filed: 1950-11-17
Abstract: 681,236. Locks. NILSSON, F. Nov. 17, 1950 [April 1, 1950], No. 28209/50. Class 44 A lock comprises a pair of adjacent sliding members connected by axially movable locking pin tumblers and a strip-like key which when inserted into the lock causes the slides to move towards the key so that the tumblers may enter to a predetermined depth corresponding perforations in the key and are thereby displaced so as to allow relative movement between the slides for opening the lock. Figs 1 and 6 show the lock in longitudinal and transverse sections. The lock mechanism is mounted between a pair of plates 11 connected by a bridge 12 at the rear end and at the other end by a cylindrical face plate 15 forming a key-hole escutcheon. The main slide 32 has transverse pins 33 engaging in oblique slots 34 in the plates 11, the projecting ends of the pins 33 being attached to over-centre springs 35 mounted on fixed pins 36. Slidably mounted in a trough cut in the underside of the main slide 32 is an auxiliary slide 38 retained by transverse pins 39 engaging in slots 40 in the walls of the trough. At the bottom of the casing are three parallel sliders 47, 48, 49 of which the central one 47 is adapted to block the passage of a spring-loaded pawl 52, Fig. 6, which retains the lock bolt 30 in the projected position against the action of a spring 53. A driving pin 54 mounted on the slider 47 engages a bore 56 in the auxiliary slide 38. Tumblers 58, 59 and 60, 61 are loaded by blade-springs 62, 63, so as normally to lock the slides 32, 38 together. A pin 42 connected to a spring blade 41 also engages aligned bores in the two slides. When the key 44, Fig. 4, is inserted into the lock it engages a slot in the driving pin 54 and displaces the slider 47. The engagement of the pin 54 in the bore 56 causes similar longitudinal displacement of the slides 32, 38 and, by virtue of the engagement of the pins 33 in the oblique slots 34 movement of the slides towards the key. This latter movement first causes a pin 68 on the slide 38 to pass through an opening 69 in the key, then the shaped ends of the tumbler parts to engage in shaped holes 66, 67 in the key and the displacement of the tumblers in the slides so that when the oblique movement is complete (Fig. 7) the line of separation of the tumbler parts coincides with the line between the slides 32, 38 which are then locked together only by the pin 42. Further inward movement of the key causes horizontal movement of the slides by virtue of horizontal extensions to the slots 34. A projecting part of the spring arm 41, moving into engagement with a sloping surface 72 on the bridge 12 lifts the pin 42 out of engagement with the slide 38 and further movement of the slide 32 is prevented by abutment with the bridge 12. During insertion of the key, the over-centre springs 35 first oppose the movement of the slides and then assist it and retain the slide 32 in the end position against the bridge 12. The slide 38 is now free to move relative to the slide 32, further insertion of the key causing the slider 47 to move out of the path of the pawl 52 (so that the bolt returns to the retracted position) as shown in Fig.8. The ends of the tumbler parts 59, 61 may be of rectangular, triangular or conical shape and to mislead persons attempting to form a key from a blank coated with wax, the tips may carry out of centre cylindrical extensions 82, Fig. 10, so that when a hole 86 is drilled with this point as centre, a part 87 is removed which should form a limiting stop for a shoulder on the tumbler. For the same purpose pins 88, 89 are mounted on the slide 38 so that a wax coated key blank would be marked thereby. If holes are then drilled to receive these pins the pin 88 will allow the tumbler part 58 to enter the bore in the slide 38 during insertion of the key, thus locking the slides together again and the pin 89 will project through to engage a fixed abutment 90, so preventing further movement of the slides. The lock may be freed by an inside handle 73 connected to a rotatable bush 75 formed with a helical slot 76 engaging a pin 77 on a bridge connecting together the sliders 48, 49 which when the handle 73 is turned are displaced so that their sloping surfaces 79 bear down on the pawl 52 which is thereby released from the slider 47.