Patent GB-972596-A (GB)
Title: Automobile door latch
IPC: E05B85/28
Filed: 1963-06-27
Abstract: 972,596. Latch fastenings. GENERAL MOTORS CORPORATION. June 27, 1963 [July 9, 1962], No. 25586/63. Heading E2A. An automobile door latch comprises a rotatable latch bolt, a detent lever 84 movable between bolt-holding and bolt-releasing positions and two separate inside operating members 114, 130 one of which 130 is at all times coupled to the detent lever to move it to bolt-releasing position and the other of which can be selectively coupled to the detent lever to move it to bolt-releasing position. In the construction shown the bolt (not shown) is in the form of a gear wheel which is fixed to one end of a shaft 80 which is rotatably mounted on a main frame 22, the other end of the shaft 80 having a ratchet wheel 78 fixed to it. The detent lever 84 is pivotally mounted on a stud 86 fixed to the frame 22 and it engages the ratchet wheel 78 by means of a tooth 88 to prevent counter-clockwise movement of the ratchet wheel. The detent lever is biased into engagement with the ratchet wheel by a tension spring 94. One leg 122 of the detent lever is engaged by one leg of a bell crank lever 120 which is pivotally mounted on a flange 24 which extends from the frame 22. The other leg of the detent lever 120 is coupled by a rod 126 to the inside operating member 130 which is arranged nearer the hinge end of the door 12 on which it is mounted in use, than the other inside operating member 114. The inside operating member 114 is coupled by a rod 110 to a leg of second bell crank lever 106 which is arranged coaxially with the bell crank lever 120; the other leg of the bell crank lever 106 engages one leg of a lever 102 which is mounted on the stud 86 coaxially with the detent lever 84. The other leg of the lever 102 is held in engagement with a lateral tab of a link 40 by a tension spring 104 hooked between the lever 102 and another tab of the link 40. The link 40 at its upper end has a bent tab 42 which is received in an aperture 44 of an outside operating lever 28 to pivotally and slidably couple the link to the lever 28 and a coiled torsion spring 46 mounted on a stud 30 on the frame 22 has one end engaging a tab 48 of the frame and the other end engaging a notched tab 50 of the link 40 so as to bias the link 40 downwardly and the operating lever 28 counter clockwise into engagement with a tab 52 of the frame. The outside operating lever 28 has a lateral flange 32 which is engageable by a push rod 34 of a push button assembly 36 which is incorporated in an outside door handle 38. Depression of the push button swings the operating lever clockwise as shown and shifts the link 40 upwardly and this swings the detent lever 84 clockwise to release the ratchet wheel 78 since a tab 98 on the link 40 underlies a shoulder 100 of the detent lever provided the link 40 is in its unlocking position as described below. Operation of the inside operating member 114 will pivot the bell crank lever 106 and this in turn raises the link 40 via the lever 102 and the tab on the link and the movement of the link 40, provided it is in its unlocking position, then raises the detent lever 84 to release the ratchet wheel. The other end of the link 40 has an elongated slot 60 and a T-shaped tab 58 of a locking lever 54 is received in the slot to slidably and pivotally couple the locking lever to the link 40. The locking lever is pivoted to the frame 22 and an over centre torsion spring 62 biases it either to its unlocking position or to its locking position, the movement of the lever to either position being limited by engagement of ears 64 and 68 with a tab 66 of the frame 22. The locking lever can be moved both by a lock cylinder 76 accessible from the outside of the door and which is coupled to the lever by a rod 72 and by a button 140 which projects through the garnish moulding of the door and which is connected to the locking lever 54 by a rod 138 and a lever 134. When the locking lever 54 is in its unlocking position the link 40 is so positioned that the tab 98 unlerlies the shoulder 100 so that movement of the link, as previously described, releases the bolt; when the lever 54 is in the locking position the link 40 is positioned so that the tab 98 is located to the left of the shoulder 100 so that movement of the link is ineffective. If the locking lever 54 is in the locking position when the door is open, closing the door causes pivoting of the detent lever 84 and an arm 142 of the detent lever engages a tab 144 of the link 40 which engages the link and moves the locking lever to its unlocking position. If however the push button 36 is held depressed while the door is shut with the locking lever in its locking position, the arm 142 moves past the tab 144 so that the door becomes locked.