Patent GB-656312-A (GB)
Title: Improved door lock for motor road vehicle
IPC: E05B65/32
Filed: 1948-12-23
Abstract: 656,312. Door latches. GENERAL MOTORS CORPORATION. Dec. 23, 1948, No 33125. [Class 44] In a door latch for a road vehicle, a pivoted latch member is retained in the latching position by a detent co-operating with a bell-crank lever having a short arm connected with the latch bolt and a longer arm engaging the detent, so that any force tending to move the bolt from the locked position (e.g. due to the compression of a sealing strip inside the door) is substantially reduced when transmitted to the detent. The latch carries a roller 16, Fig. 2, adapted on closing the door to pass along an inclined dog-leg slot 7, 8, in a keeper 3 secured to the door jamb. The roller is carried on a pivoted arm 11, Fig. 5, carrying a stud 23 engaged in a slot 22 in the short arm of the bell-crank lever 20 pivoted at 21. Teeth 24. 25 on the longer arm are engaged by the detent 26 carried on a lever 27 pivoted at 28. The engaging surfaces of the detent 26 and teeth 25, .24 are arcuate about the pivot 28 so that the initial displacement of the detent causes no movement of the bolt. The detent is urged to the engaging position and the latch bolt is urged to the release position by a spring, 29. A plate 86 carried on the upper arm on the detent lever 27 is engaged by a shoulder 71 on a slidable member 68 for release from the outside and by a flange 92 on a slidable lever 90 for release from the inside. An outside handle 45, Fig. 3. is formed with a bore 46 at one end to receive a push-button 47 spring-loaded to the outer position and connected to a push-rod 53. The push-rod, which is of square section passes through a hub 66 with a corresponding opening and abuts one arm of a lever 61. the other arm of which abuts an upstanding flange 75 on the end of the slider 68 so that when the button is pressed in the slider is projected to engage the shoulder 71 with the arm of the detent lever which is thereby rotated to release the latch bolt. The slider 68 is mounted in a carrier 56, pivoted at 58 and is thereby allowed a small pivotal movement sufficient to place the shoulder 71 beneath the plate 86 on the detent lever so that when the outside button is pressed the slider moves idly. The slider is moved to this locked position by an inside finger piece connected by a link 82, Fig. 5, to a lever 77 having flanges 78 embracing an extension 76 on the slider. An overcentre spring 81 retains the parts m the locked or unlocked positions. A barrel lock 49, Fig. 3, in the outside push-button is adapted to rotate the spindle 53 and the hub 66. Arms 64, 64a on the hub engage either side of a projection 67 on the carrier 56 and by rotation of the key 54 displaces the slider into or out of the locked position. An inside pushbutton is connected through a link 96 to a spring-loaded lever 93 connected to an arm of the sliding lever 90 so that when this button is operated the lever 90 is displaced to engage the plate 86 and release the detent. The tooth 24 corresponds to a part latched or safety position of the latch bolt. If the slider is in the locked position when the door is shut the upper surface of the detent rises to engage the shoulder 70 on the slider and returns it to the unlocked position unless the outside push-button is held pressed in during the operation. In the latter case the door is locked and can only be released by using the outside key. In another form, Fig. 19, the latch lever carries a pin 111 engaged in a slot 112 in the bell crank lever 110. A tooth 113 is adapted to engage a detent 117 on the lever 115 in the part latched position and in the fully latched position a detent 121 on an auxiliary catch 118 pivoted at 119 to the main lever 115. A flange 126 on the catch 118 engages the rear edge of the main lever 115 so that both detents move to the releasing position together when the lever 115 is rotated in an anticlockwise direction. A slider 133 mounted in a guide 132 at one end and on a pin 135 at the other carries a lever 136 pivoted at 137, the free end 144 being embraced by flanges 145 on a lever 146 controlled by an inside finger piece through a link 82. The slider 133 is displaced by the outside push-button as before and this normally causes a shoulder 141 on the lever 136 to engage a projection 142 on the lever to release the detents. The lever 136 may be displaced to move the shoulder out of the path of the projection 142 by manipulation of the lever 146 from the inside or by an arm 139 controlled by the outside key lock as before. If the lever 136 is in the locked position when the door is closed, a pin 150 engages the cam faces 152, 153 to return the lever to the unlocking position by contact with a lug 156 with the shoulder 157. An inside push-button causes movement of a link 96 connected to a slotted lever 123 engaging a pin 125 on the detent lever to release the latch.