Patent GB-1229659-A (GB)
IPC: E05B55/00
Filed: 1968-06-13
Abstract: 1,229,659. Locks. L. F. VAN DER WALT. 13 June, 1968 [14 June, 1967], No. 28081/68. Heading E2A. A door lock comprises a housing 10, a bolt member is slidable within the housing and having a head 12a and a tail portion and which is linearly displaceable between positions with the head protruding from and retracted into the housing, a spring 14 resiliently biassing the bolt member to the position with the head protruding from the housing, an intermediate member 16 mounted within the housing and adapted to execute a first action in which it engages with the bolt member to displace it so that the head is disposed in the retracted position, and a second action in which it locks the bolt member with the head in the protruding position, a spring device adapted to restrain execution of the second action of the intermediate member, an actuating member 26 mounted within the housing and adapted to engage with the intermediate member to impart the first action to it, a locking member 32 mounted within the housing and adapted to engage with the intermediate member to impart the second action to it, an operating handle not shown exteriorly of the housing and connected by a shaft to the actuating member, and an operating element (not shown) to control the operation of the locking member and having a portion penetrating the housing to engage the locking member and a portion exteriorly of the housing on which an operating action is applied. In the construction shown in Fig. 1 when the actuating member is rotated in the direction of the arrow C a projecting element 28 of the member 26 engages a part 30 of the intermediate member 16 to rotate it in the direction of the arrow A which causes an element 18 of the intermediate member to engage a stop element 20 of the bolt member to withdraw the head of the bolt member into the housing. Two locking members 32 are provided one of which is operable from one side of the housing and the other from the opposite side and they are separated by a barrier plate 34; the operating element for each is either by a key or alternatively a fixed lever on the outside of the housing and rotation of either locking member in the direction of the arrow D causes an engagement element 36 of the locking member to engage a projecting portion 38 of the intermediate member to rotate the intermediate member in the direction of the arrow B so that a projecting element 22 of the intermediate member engages a shoulder formation 24 of the bolt member to lock the bolt member with its head in the protruding position. In the locking position of the intermediate member the actuating member 26 is free to rotate in the direction of the arrow C so that the operating member is freely rotatable. The intermediate member, the actuating member and the locking members are all biased by springs 49, 27, 50 to their normal positions. Operation of either of the locking members 32 can be prevented by stop means comprising a pair of shoes 40 which are connected via links 42 to a disc 44; a portion of the disc protrudes beyond the housing and by rotating the disc one of the shoes is moved until it engages with a corner formation 48 of the corresponding locking member 32 to prevent its rotational displacement. A modified construction is described in which each locking member instead of being directly moved by a key or an outside lever is moved indirectly by a follower and this construction has a modified stop means comprising a pivotally mounted lever which is engageable with either of the locking members from a central position in which it engages neither. Fig. 4 shows a construction in which instead of a pair of locking levers 32 a slide plate 60 is provided which has a dog's head formation 62 which is engageable with the intermediate member 16 to move it to the position in which it locks the bolt with the head protruding. Movement of the slide plate 60 is controlled by one or more lever tumblers 70 which must be raised by a key so that a stub 68 can pass through a gate in the or each tumbler in a modification of this construction the slide 60 is extended so that its end portion projects through a wall of the housing to form a bolt head. The construction shown in Fig. 4 can be modified by providing a lever locking member in addition to the locking slide plate 60, this is operable independently of the locking slide plate 60 from both sides of the housing by means of a removable key or a lever fixed to the locking member. The construction shown in Fig. 4 can also be modified by substituting a cylinder locking mechanism for the slide plate 60 and the lever tumbler or tumblers; the cylinder locking mechanism operates a locking lever corresponding to the lever 32 via another lever.