Patent GB-606339-A (GB)
Title: Latching mechanism
IPC: E05C3/36
Filed: 1944-09-06
Abstract: 606,339. Latches. ENDTER, W. A. Sept. 6, 1944, No. 17046. Convention date, March 17, 1944. [Class 44] A latch mechanism, particularly of the type having a rotary bolt latch urged in latching direction by one or more spring - pressed cams, comprises a bolt movable into latched engagement with the keeper, a cam movable to urge the bolt against the keeper, and holding means coacting with the cam to hold the latter against retrograde movement in its bolt-holding travel. In the form shown in Figs. 1 and 2, the rotary latch bolt 16 is carried in the lower part of a projecting housing 13, and makes contact with a fixed boss 15 on the door post, while the upper part of the housing comes in contact with a lug 14 on the post. The latch 16, of the type comprising several heads 20, is held against rotation in unlatching direction by the cam and dog assembly 22, Fig. 4, which is slidable vertically between the wall 26 of the housing and a guide 27. Pivoted within the cam 23 is a dog 29 having a rounded nose projecting through a slot in the cam and engaging the wall 26 of the housing, and the cam is urged downwardly by a spring 31 bearing on the dog 29. The latter is movable by a plate 34, Fig. 5, having projections 35, 36 which extend through a slot in the cam above and below the dog. The mechanism may include a safety catch 41 pivoted at the top of the casing and engaging a series of notches 44-46 on the under surface -of the lug 14. Release of the latch is effected by means of a spring-urged plate 50 mounted to rotate on the shaft 21, a lug 51 on plate 50 first engaging the lower edge of plate 34, releasing dog 29 and then lifting cam 23. A part 52 of plate 50 projects through a slot in the case flange 11, and is engaged by an arm 71 of a lever 63, adapted to be operated by a follower 69 on the spindle of an outside handle, or by a link 68 connected to an inside handle. A locking plate 59, when moved downwardly through the intermediary of a bar 72, by a push-rod 79, or by operation of a key-lock, locks the plate 50 against release movement by dogging a lug 57 on the plate. In a modified construction, a pivotally mounted cam, locking dog, and releasing element assembly is used. The bolt 85, Figs. 7 and 8, comprises inner and outer sections 86, 87, separated by a circular flange lying in an opening in the case section 90, and rotates on a pin 91. The casing carries above the bolt a hollow lug 94, the under face of which engages the keeper 96, Fig. 11, on the door post, which is received between the lug and the bolt. The bolt is urged into latching engagement with the keeper by a pivoted cam 97, Figs. 7 and 10, which carries a pivotallymounted locking dog 99 engageable with a stationary curved surface 101 to hold the cam against retrograde movement. Pivoted on the same pivot as the cam is a member 102 having lugs 103, 104 adapted to engage the upper and lower edges respectively of dog 99. A spring bearing on member 102 normally urges dog 99 and cam 97 in bolt-advancing direction, through reaction of the dog on surface 101 and the thrust of the cam on the inner section of the bolt. The lug 94 has mounted within it a safety catch 111, Fig. 8, adapted to engage in notches in the upper surface of keeper 96. A depending arm 117 on the safety catch is engaged by the releasing plate 121, Figs. 7 and 10, to disengage the catch at the same time as the cam 97. Plate 121 is pivoted on the bolt pin 91, and has a lug 122 engaging the member 102 to release the cam, and a lug 123 engaging arm 117; it is rotated to release by downward movement of a link 126, actuated from outside, or by a lever 127, Fig. 8, operated by a link 133 connected to an inside handle. The fully released position is as shown in Fig. 10, but when the operating handle is released, the mechanism is returned to the position of Fig. 7 by action of the spring controlling the member 102. As the door is closed, the bolt is rotated by contact with the keeper, lifting the cam and the member 102 and then allowing them to fall into the position shown in Fig. 9, after which the cam is thrust against the bolt to urge it against the keeper and dog 99 is pressed against surface 101 to lock the cam. The releasing plate 121 can be locked by means of a lever 136, Figs. 7 and 10), operable by a push-rod 140 or by means of a key lock. The outside handle may take the form of a hinged press plate 156, Fig. 7, conforming to the control of the door wall, and connected to the link 126. Specification 617,775 is referred to.