Patent GB-189815729-A (GB)
Title: Improvements in Locking Devices for Doors and the like.
Inventor: KUNZELMANN CARL
Filed: 1898-07-18
Granted: 1898-10-01
Abstract: 15,729. Kunzelmann, C. July 18. Locks, key; latches; escutcheons, keyhole.-A latch-lock for doors &c. has a locking-bolt R controlled by levers z (shown dotted). A crank lever, one arm a of which is shown, is pivoted on the back of a fixed plate p and normally engages recesses in the levers to pre. vent them from being moved by a key. The key, Fig. 17, has two spring pins m<1>, n<1>, which can be pressed forward by a knob m and sliding ring n<x> respectively after the key has been inserted. In the locked position shown, a tumbler r', pivoted at r<2> on the bolt, is held in the position shown by a leaf spring q<4>, projecting through a recess in the bolt. By placing the key on a hollow key-pin b<1> and projecting the pin m<1> through a hole r<5> in the bolt, the spring q<4> is disengaged, and the tumbler falls to allow the bolt to be retracted, after disengaging the arm a, by the key-bit engaging the face r<4> of the tumbler. The disengagement of the arm a is effected by projecting the pin m<1> through a slot p<3> in the plate p and turning it in the direction of the arrow to raise the second arm of the crank lever, which is then held by a leaf spring on the back of the plate p. The crank lever is set free to lock the levers after an operation of the bolt by pressing back the leaf spring by projecting the pin m' through the slot p<3>. The tumbler r<1> is set after again shooting the bolt by a further turning of the key, the bit engaging a lug r<3> as indicated. A device for locking the bolt in either position consists of a spring plate b on the case, with pins b<3>, b<4>, one or other of which engages an aperture r<0> in the bolt at either end of its travel. To disengage the pins, the pin n<1> of the key is projected through the hollow key-pin b<1> to push back the plate b, the ring n<x> being held while the key is manipulated. The keyhole is covered by a plate c, Fig. 12, pivoted inside the case C. This plate has a keyhole slot c', and an aperture c<4> in which engages a pin i<4> projecting inwards through a slot c<0> in the case from a disc, revolubly mounted in a boss on the outside. Keyhole slots in the disc and boss are normally in alignment, and a special key is inserted till its bit rests in the disc, allowing the latter to be turned in the direction of the arrow till the slot c' in the plate c is in alignment with the slot C' in the boss. The plate is there held by a lug c<3> engaging a pin l<3> on the plate b. The disc is then turned back till all three slots are in alignment, when the special key can be withdrawn and the lock key inserted. The movement of the plate b at each operation of the bolt disengages the pin l<3>, and allows the plate c to be returned by a spring c<2> when the lock key has been withdrawn. In the shot position the latch bolt F is held by an arm f<3> pivoted on the locking-bolt, a lug f on the arm resting against the lower side of the bolt, but, when the latter is retracted, the latch bolt may also be retracted by a second operation of the key, the bit engaging the lug f<5>. The latch bolt may be held in the retracted position by a lever operated by a knob and engaging a recess in the bolt.