Patent GB-1107972-A (GB)
Title: Latch mechanism for hinged doors
IPC: E05B85/24
Filed: 1965-07-28
Abstract: 1,107,972. Latch fastenings. J. H. ROETHEL. 28 July, 1965 [14 Sept., 1964], No. 32178/65. Heading E2A. A latch mechanism for a hinged door comprises a support member 11, a pair of latch device means pivotally mounted on said support member for pivotal movement between latching and unlatching positions, a pair of detent means 21, 25 pivotally mounted on said support member and engageable respectively with said latch device means to hold the same in the latching positions, said detent means being coupled to each other for movement in unison to and from latch device means engagement, and displacing means 41, 45 engageable with one of said detent means for displacing same and thereby the other detent means from engagement with said latch device means. As shown each latch device means comprises a jaw element 13 and a control plate 15 rigidly coupled together by a pivot shaft 14; the shafts 14 extend through bearings in the support 11 so that the jaw elements 13 are on one side of the support and the control plates 15 on the other side. Each jaw element has an arcuate recess adapted to engage a cylindrical keeper pin (not shown). Each control plate 15 is provided with two peripherally spaced ratchet teeth 18 and 19 so that when the detent means are engaged with the ratchet teeth 18 a safety latching condition is obtained and when the detent means are engaged with the ratchet teeth 19 full latching condition is obtained. The detent means 21 has three arms 23, 32 and 38 the arm 23 engaging the control plate 15, the arm 32 being engaged by the displacing means 45 and the arm 38 being engaged by the displacing means 41. The detent means 25 has two arms 27 and 28, the arm 28 engaging the control plate 15 and the arm 27 being connected by a link 31 to the arm 32 of the detent means 21. A spring 35 extends between the arm 32 and the support 11 to bias the detent means into engagement with the control plates and a spring 56 extends between the control plates to bias the jaw elements 13 to the unlatching positions. The displacing means 41 is the stem of a push button which in use is mounted in a door handle assembly fastened to the exterior surface of the outer door panel. The displacing means 45 is a bell crank, one arm 44 of which engages the arm 32 and the other arm 47 of which is connected to remote control mechanism mounted on the inner panel of the door. To lock the latch mechanism to prevent disengagement of the detent means from the control plates a locking lever 48 is provided. This is pivotally mounted on the support 11 and is biased by a spring 55 to unlocking position. The locking lever has two arms 49, 51 the arm 49 being engageable underneath the arm 32 of the detent means 21 in locking position to prevent its movement to unlatching position. The other arm 51 of the locking lever is in the path of the arm 44 of the bell crank 45 and movement of the bell crank in the opposite direction to that which moves the detent means to unlatching positions causes the arm 44 to engage the arm 51 to move the locking lever to locking position. When the jaw elements are in unlatching positions the detent means 21 is held in a position in which the arm 42 prevents the arm 49 of the locking lever moving to locking position.