Patent GB-805952-A (GB)
Title: Improvements relating to automobile door latches
IPC: E05B65/32
Filed: 1956-08-16
Abstract: 805,952. Automobile door latches. GENERAL MOTORS CORPORATION. Aug. 16, 1956 [Sept. 13, 1955], No. 25070/56. Class 44 An automobile door latch comprises a frame having two plates at an angle to each other, one plate 24, Fig. 3, having a pivoted latch bolt 28 and a pivoted detent 36 engageable with ratchet teeth 30 to prevent unlatching of the bolt; and the second plate 26 having a guide stud 44 on which is slidably mounted a slotted link 46 engageable with the detent to move it out of engagement with the teeth 30, the stud 44 being carried on a locking lever 40 by which the link 46 may be pivoted to a locking position. General. The invention is described with reference to a front car door latch 18, Fig. 1, which can be (a) opened from inside the car by handle 94, (b) locked from the inside by button 70, (c) opened from the outside by button 62, (d) locked from the outside by a cylindrical lock 81. Modifications of the latch 18 are described by which a rear door latch 20 can be (e) opened from the inside by handle 112, (f) locked from the inside by push button 70, (g) opened from the outside by push button 114. Opening latch 18 from inside by handle 94, Figs. 1 and 3. Operation of handle 94 pulls rod 92 to turn lever 88, about 90, thus turning plate 80 about 82 against the action of spring 84; a notch 80c in plate 80 engages an arm 36a of the detent 36 to swing the detent out of engagement with the cam 30 and so release the latch bolt 28. Opening latch 18 from outside by button 62, Figs. 1 and 3. Depression of button 62 pulls rod 60 which turns a lever 52, pivoted at 54 to plate 24, clockwise so that a tongue 56 of plate 52, engaged in a slot 56 of link 46, slides the link 46 on stud 44 so that its shoulder 50 engages the detent arm 36a to move the detent 36 from engagement with the cam 30. Locking latch 18 from inside. Depression of button 70 and rod 68, Fig. 1, causes lever 65, Fig. 3, to pivot clockwise about 65a so that lever 40, connected to lever 65 by a pivot 64, turns about pivot 42 and swings the link 46 about the tongue 56 from engagement with the detent arm 36a; the shoulder 50 then by-passes the arm 36a upon sliding of the link 46. Hence operation of button 62 moves the link 46 idly without releasing the latch bolt. The lever 65 is held in either the lock position or unlocked position by an overcentre spring 72. Locking from outside by a cylindrical lock 81. A key pushes rod 78 downwards to rotate a plate 74, Figs. 1 and 3, counterclockwise about pivot 76 so that an extension 18 pushes a plate 66 which is connected to lever 40 by pivot 64, and thus swings link 46 out of engagement with the detent 36. Prevention of unintentional locking of latch 18. If link 46 is in the locking position when the door is shut, rotation of the bolt 28 causes the detent 36 to ride over the cam teeth 46 and so move plate 80, through the arm 36a, about 82 so that its tongue 80f engages a tongue 96 of link 46 to move it to the unlocked position. To obtain a "keyless" locking the link 46 is moved to the locking position by button 70 and by maintained pressure on the button 62, during door closing, the link 46 is moved so that the tongue 80f by-passes the tongue 96 and so will not unlock the latch. In a modification to latch 18 in Fig. 4, the lever 88<SP>1</SP> is of different shape to lever 88 and a lever 100 is pivoted on the same pivot 90 as lever 88', the lever 100 having two meeting slots 102 and 104 while lever 88<SP>1</SP> has a slot, not shown, in line with slot 102. A spring rod 106 has its lower end bent and passing through the aligned slots in levers 100 and 88<SP>1</SP> so that when its other end is held in one position in slot 108 in lever 65 by spring 110, movement of lever 100 also moves lever 88', whereas in another position, the lower end is aligned with slot 104 and the lever 100 can move idly without moving lever 88'. The rod 106 being moved to the selected position in slot 108 by a tool inserted through a small aperture in the door. To open latch 20 from inside by handle 112, Figs. 1 and 4. Operation of handle 112 moves rod 92<SP>1</SP> to rotate lever 100 about 90; if the upper end of rod 106 is in one arm of slot. 108 and the lower end is in slot 102 then levers 100 and 88' are connected and move in unison to swing the detent 36, whether or not the door is locked; if the upper end of rod 106 is in the other arm of slot 108 and the lower end is in slot 104, then the lever 100 moves idly without moving lever 88<SP>1</SP>. The locking of latch 20 by button 70 is similar to that in latch 18. To open the latch 20 from outside. The push button 114 acts through a short rod 120 to pivot a bell-crank 116, pivoted at 37 to plate 24, and so move the link 46 through link 122 and lever 52 to move the detent 36. A modification for operating latch 20 by a remote external push button in Figs. 5 and 6 (not shown), has a support bracket fixed to plate 26 carrying a lever, one end of which is connected to a rod similar to rod 60 in Fig. 1 and the other end carrying a tongue for engagement with the slot 58 in lever 46.