Patent GB-954074-A (GB)
Title: Improvements in vehicle door latches
Inventor: MOSS NORMAN SIDNEY
IPC: E05B65/32
Filed: 1961-03-27
Abstract: 954,074. Latch fastenings. WILMOT BREEDEN Ltd. March 16, 1962 [March 27, 1961], No. 11103/61. Heading E2A. A vehicle door latch has means 10 operable externally of the vehicle to release the latch for opening of the door and means 32 operable internally of the vehicle either to lock the latch against operation by the externally operable releasing means or to release the latch for opening of the door and has blocking means 30 which is accessible only at the free edge of the door when the door is open, for manual movement between a position in which it is movable by the internally operable locking and releasing means into blocking relation with the externally operable releasing means to prevent operation thereof and a position in which it blocks the operation of the internally operable locking and releasing means while leaving the externally operable releasing means free for operation. In the construction shown a bolt 11, which is of the zero torque type, is mounted on a shaft 16 which is rotatable in a bearing in one end wall of a housing. On the other side of the housing wall the shaft carries a radial operating arm 21 which is fixed to the shaft and an operating lever 22 which is free to rotate on the shaft and has three radial arms 23, 24, 25; the arm 23 is engageable by the externally operable releasing means, which as shown is a push button, and this pivots the lever and causes a lug 27 to bear on the arm 21 and so turn the bolt to release it from the striker. The internally operable locking and releasing means is in the form of a quadrant which is pivoted to a wall 31 of the housing so that it is at right angles to the arm 21 and lever 22 and a lug 37 of the quadrant is engageable with a lug 28 of the lever 22 and hence when the quadrant is turned by an inside handle, which is connected to it by linkage, the bolt is also moved to releasing position. The blocking member 30 is a cranked lever, the pivot 41 of which can both pivot and slide in a slot 42 in the end wall of the housing the lever having a tongue 45 which, if the lever is raised about its pivot, is brought into the path of the third arm 25 of the operating lever 22 to prevent unlatching rotation of the arm. The free end portion 50 of the blocking lever overlies a projection 40 of the quadrant so that as the quadrant is rotated in the locking sense from the neutral position, which rotation is opposite to its latching rotation, the projection 40 raises the blocking lever into its blocking relation with the arm 25 of the operating lever and so prevents release of the bolt by the push button 10. This raising of the blocking lever can only take place when the pivot is at the end of its slot 42 in the housing adjacent the outside of the door; when the pivot is moved to the other end of the slot the free end 50 of the blocking lever enters a hole 51 in the rear wall 31 of the housing and this prevents the lever being raised; this is the child safety position and prevents the child locking itself inside the car and also prevents the child from opening the door since the blocking lever has a projecting tongue 52 which lies underneath the third projection 40 of the quadrant and this in conjunction with the end 50 prevents the quadrant being rotated. The bolt and the blocking lever are both provided with biasing springs.