Patent GB-194721-A (GB)
Title: Safety lock
IPC: E05B67/24
Filed: 1923-03-12
Abstract: 194,721. Spruth, H. March 13, 1922, [Convention date]. Locks, revolving-barrel; padlocks; keys; lacking sliding latches; locks, preventing drilling of. -Circular locking members each having a stud projecting from a central aperture for travelling along a groove in a key inserted into the aperture, are freely rotatable, allowing the insertion of the key to rotate them by varying amounts to align notches in their peripheries so that a partial rotation of the key after insertion brings the aligned notches below a locking member, which is thus released. Figs. 2 and 6 show the invention applied to a padlock. Locking rings 5, of the form shown in Fig. 5, are housed in a cylinder 4 which has a part cut away to house one leg 10 of the removable shackle, the other leg passing into the space between the cylinder 4 and external cover. The rings are held in the cylinder by end plates 1, 2, holes 8, 9, in the plate 1 allowing of insertion of the shackle legs, and a hole in the plate 2 allowing of insertion of the key. Collars 12 limit the insertion of the shackle legs. Fig. 6 shows the shackle in the locked position, the shackle having been moved bodily to engage notches 11 in its legs with the coverplate 1, and a notch 14 with a tongue 13 stamped from the cylinder 13. To release the shackle. the key is inserted, the pointed end 18 guiding the pins 6 of the rings into the groove 38 in which they travel, causing rotation of each ring until their notches 7 are aligned. The key is then turned to a mark on the casing to bring the aligned notches under the leg 10 of the shackle, which can drop bodily out of engagement with the plate 1 and projection 13, and be completely removed from the casing. Figs. 9 and 10 show the invention applied to a door lock. The rings 5 are housed in a cylinder 21 in a slit in which is carried the locking bar 27, urged inwards by a spring 29. The fixed external casing comprises three parts 23, 24, 25, the parts 23, 25 both having keyholes. Between the parts 24 and 25 is a toothed segment 30, fixed to the cylinder 21, co-operating with teeth on a plate 31 which rides on the spring bolt 32. On insertion of the key into the keyhole of the plates 23, or 25, the notches of the discs 5 are brought into alignment, the groove 38 of the key being symmetrical about its middle point to effect this from either side. The key is then turned until a projection 39 on it can engage a notch 40 in the cylinder 21, when the aligned notches 7 are under the bar 27 which is pressed out of engagement with a notch in the fixed casing 23, 24, 25. If the key is now turned, the sector 30 on the cylinder 21 moves the plate 31 until it contacts with the head 35 of the bolt, to block it, when withdrawal of the key will rotate the rings 5 to force the locking- bar 27 into the notch 41 in the fixed casing. If the key had been further turned, the plate 31 would have thrust out the head 35 of the latch bolt still further, and withdrawal of the key would have caused the bar 27 to have been locked in the groove 42. The locking-bar 27 may be formed of several parts not in axial alignment, to avoid its being drilled out.