Patent GB-1112158-A (GB)
Title: Door latches for motor vehicles
Inventor: GREENLAND RALPH
IPC: E05B65/34
Filed: 1965-11-25
Abstract: 1,112,158. Latch fastenings. GENERAL MOTORS Ltd. 19 Oct., 1966 [25 Nov., 1965], No. 50094/65. Heading E2A. A motor vehicle door latch comprises a rotatable bolt 3 a detent lever 7 to prevent rotation of the bolt and carrying a movable thrust element 17 against which when in operative position thrust is applicable to rotate the detent in bolt freeing direction and an actuator lever 18 which is pivotally movable in one direction to shift the thrust element out of its operative position and pivotally movable in the other direction to rotate the detent lever in bolt freeing direction. In the construction shown, the bolt 3 is in the form of a toothed gearwheel which is mounted to rotate freely by means of a spindle 4 passing through a jam plate 1, the gear wheel being fixed to the spindle 4 on the outside of the plate 1 and, on the inside of the plate 1 and fixed to the spindle, there is a toothed ratchet wheel 6 which is engaged by the detent lever 7 which is biassed by means of a spring 30. The detent lever has three arms 9, 10, 11 the arm 9 carrying a detent toothed 12 for engagement with the ratchet wheel 6; the arm 10 is connected to one end of the spring 30 the other end of which is hooked to a tab 31 on the plate 1: the arm 11 extends upwardly and is of right angled section so that it has a tab 13 which faces a plate 2 of the latch frame which is at right angles to the plate 1 of the frame; the tab 13 has a cut away portion 14 opposite to a slightly larger cut away portion 15 in the plate 2 and these cut away portions are aligned with the axis and inward part of thrust of a push button not illustrated fixed on the outside of the door. The push button is connected to a rod 16 and when thrust is applied to the push button, the rod 16 engages the thrust element 17 which is pivoted by means of a stud to the tab 13 and which is engaged the rod when it lies across the cut away portion 14 in the detent lever; the thrust element 17 is pressed about its pivot into the operative position by a spring 22. The actuator lever 18 is pivoted to the outside of the plate 2 by a stud 19 and is normally positioned in a central unlocking position in which the door can be latched and unlatched on the outside. From this normal position the lever can be moved about its stud 19 anticlockwise in Fig. 3 to effect locking of the door the movement engaging the lever with a tab 21 on the thrust element 17 and pivoting the thrust element into an inoperative position in which the first element is completely clear of the path of the push button rod 16 so that movement of the push button rod is idle. The actuator lever has a cut away portion 25 to allow free passage of the push button rod. When the actuator lever is moved in the other direction into the unlatching position, a projection 28 of the actuator lever lying below the arm 10 of the detent lever lifts the detent lever and moves it in the bolt freeing direction. The actuator lever also has a projection 27 which lies above the arm 10 of the detent lever and whose function is to rotate the actuator lever if it is put in the locking position while the door is open; during closing movement of the door the rotation of the latch bolt causes the detent lever to pivot so that its arm 10 contacts the projection 27 to shift the actuator lever back to the unlatching position. The actuator lever is biassed by an over centre spring 29 so that it is retained in either its normal latching position or its locking position. The actuator lever is intended for operation by an inside handle which is connected to the lever by means of a rod engaging a hole 34 at the top of the lever 18. In the construction shown the bolt is partly enclosed by a casing 5 and the spring 30 is encased in a flexible cover to prevent rattle; the actuator lever 18 carries a blade spring 32 which bears against the face plate 2 and steadies the actuator lever against wobble the detent lever 7 is steadied against wobble by contact of its upper part with arcuate pressed in portion 33 of the face plate 2. A key operable barrel lock (not shown) is used to lock the door from the outside, the lock cylinder having a upwardly projecting arm 36 having at its top end a pin 37 which projects through a window 35 in the actuator lever. When the key is turned in locking direction the pin 37 contacts the left hand edge of the window 35 and turns the actuator lever into locking position, the size of the window 35 and the position of the pin allow lost motion so that the pin does not interfere with locking of the door by operation of the inside handle. In a modification of the latching mechanism the ratchet wheel 6 is omitted and the bolt wheel 3 is directly engaged by the tooth 12 on the detent lever which is bent to project to an aperture in the plate 1.