Patent GB-496934-A (GB)
Title: Improvements in and relating to door fastenings particularly for motor vehicles
IPC: E05B65/32
Filed: 1937-03-03
Abstract: 496,934. Latches. MAY, C. H. March 3, 1937, Nos. 6376 and 19980. [Class 44] A door latch has a pivotally mounted latch. member moved out of the latched position by the release of energy stored, during the closing of the door; by the movement of a pivoted loading member. The latch member 22, Fig. 2, mounted on a pivot pin 25 and loaded by a. spring 29, has a tail 37 which bears on an arm, 33 connected by a spring, 34, to the loading member 23. The spring 34 is stronger than the spring 29, but is prevented from overcoming it by a pin 35 which co-operates with an abutment 36 on the lever 31. If the lever 31 is moved downwards by the rod 17, the abutment 36 moves clear of the pin 35 and allows the spring 34 to rotate the arm 33 ; this in turn causes the member 22 to rotate clockwise about the pivot 25, and clear the notch 28 in the striking plate 27 so that the door can be pushed open. During the door-opening movement, the latching and loading members are forced towards each other by the spring 29 and the tracks 38 of the striking plate 27 and when they are clear of the striking plate both springs 29, 34 are substantially unstressed. If the door is now pushed to, the members 22, 23 will ride along the tracks 38 and retension the springs 29, 34, but as the pin 35 is behind the abutment 36 of the lever 31, the initial latched position will be resumed. The latching and loading members 22, 23 may have sleeves 39, 39a at their ends to reduce wear. A mechanism for operating the rod 17 is shown in Fig. 6. In the position shown, downward movement of either button 15 or button 15a causes downward movement of the rod 17 ; but if the button is raised to the position shown in dotted lines, the links 18 will be drawn clear of the shank of the pressbutton 15a so that operation of the latter will not operate the rod 17. A modification, in which the latching member 62 is on a common axis 64 with the loading member 63 and connecting member 65, is shown in Fig. 7A. Lugs 68, 69 on the connecting member 65 co-operate with projections 66, 67 on the latching and loading members. When the door is closed the latching member 62 enters the striking plate, but since there is no recess for the loading member, the spring 71, which is gripped between the loading member and the upturned edge 73 of the connecting member 65, is placed in tension. To open the door, the detent plate 74 is moved to allow the member 65 to rotate and to take with it by means of the lugs 66, 68 the latching member 62. This stresses the spring 70 and when the door is fully opened, the member 62 is forced outwards carrying with it the connecting member 65 so that the detent plate 74 can return to its initial position. The detent plate 74 may be operated directly by the inside push-button and by the outside push-button through a hook-like member 79 which actuates the plate through an extension 77a. By raising the plate 74 by means of the inside push-button, it is placed in a position in which the hook is not able to abut against the top edge of the extension 77a. A further modification which has a latching member 80 and a loading member 81 is shown in Fig. 13. The striking plate 82 in this case has an additional pair of notches 84, 85. The latch is operated by a press-button through a pivoted lever 86 which actuates an abutment lever 87 pivoted on the same pin 88 and attached thereto by a lug 89 which passes through a hole 90. A short lever 91, bent over at 93 so as to abut in certain positions of the mechanism against a stop 94 of the abutment lever 87, has a tail 95 between which and the tail 96 of the loading member 81 is a compression spring 97. A compression spring 99 acting between the arm 98 of the latching member and the lever 86 tends to turn the latter in a clockwise direction. When the press-button is depressed, the lever 86 turns the lever 87 counterclockwise so that the stop 94 clears the end of the lever 91. This allows the spring 97 to rotate the member 80 so that it clears the latching notch 83. This permits the door to be pushed open, the latching member turning clockwise as it passes along the track 100 until it is about to enter the safety catch notch 84. If pressure is still maintained on the push-button, the latching member will rise under the action of the spring 97 and the door may be pushed fully open. As the door is closed, the latching member is forced down by the surface 102 of the striking plate so that the arm 98 presses the lever 91 beyond the stop 94 on the abutment lever 87 which the spring 99 returns to its initial position. The latching and loading members then move apart along the surfaces 103 until the springs 97 and 99 bring them into the safety notches 84, 85. On further inward movement of the door the members ride up the surfaces 104 into the initial position shown in Fig. 13. If the push-button is pressed, but the pressure is not maintained, the mechanism will take up the position shown in Figs. 19, 19A in which the latching and loading members lie in the safety notches 84, 85 and the abutment lever 87 has returned to the normal position. To open the door, the lever 86 has to be de-. pressed and if pressure is maintained, the latching and loading members are moved apart by the action of the hump 120 on the abutment lever on the hump 121 of the loading member. A fairly heavy pressure is necessary as the loading member 81 has to be moved against the action of the spring 97. The door may then be opened as before, but if the pressure is released when the latching and loading members leave the safety notches, they will take up the position shown dotted in Fig. 19A. In this position, they move along the surfaces 103, 104 of the striking plate against the action of the springs 97, 99 into the initial position shown in Fig. 13. The lever 86 may be connected to the inside push-button whilst the outside push-button may be connected to another lever also pivoted on the pin 88. In the normal position of the lever 86, an abutment on the second lever may co-operate with the lug 106 on the lever 86 to operate the latch but if the inside push-button is lifted, the lever 86 pivots about the pin 89 to cause the pin 88 to move to the other end of the slot 108 and cause the lug 106 to be clear of the path of the abutment on the second lever. In this condition, the latch cannot be operated by the outside push-button. A modification in which the lever 86 may be operated by a tumbler lock is described. The later Provisional Specification describes modified spring arrangements and a modified form of connection between the levers 86, 87.