Patent GB-822406-A (GB)
Title: Improved latch for vehicle doors
IPC: E05B65/32
Filed: 1957-01-25
Abstract: 822,406. Latches. MAGLUM S. A. Jan. 25, 1957 [Jan. 27, 1956; April 18, 1956], No. 2758/57. Class 44 Relates to door latches of the type comprising a keeper 7, rotary latch bolt 15 mounted in a case 1 and spring-urged to the latching position to co-operate with notches 8, 9 in the keeper 7, the bolt being retractable by a push-button 43 on the outside of the door or by a handle on the inside of the door. According to the invention, the latch comprises a thrust member 38 connected to the push-button for axial movement therewith and adapted for rotation about the axis thereof by a key into an "active" position, in which during the axial movement of the thrust member, it abuts against a tab 19 on the latch bolt 15 and causes rotation of the latter towards its retracted position, or into a "passive" position wherein the thrust member is removed from the tab of the latch bolt and renders the push-button 43 inoperative. As shown, the case 1 comprises a plate 2 having a flange 2a and a cover 3 which is shaped to provide a recess 6 and to receive the keeper 7. The latch bolt 15 is pivoted about a pin 16 and is formed with a nose 17 for engaging the notches 8, 9 of the keeper, a lug 21 for a return spring 22, a tab 20 and the tab 19. An actuating lever 28 and a locking lever 29 are mounted on a common pivot 27 between a pair of upstanding plates 25, 26 on the cover 3 and are connected respectively to an inside door handle (not shown) and an internal push-button. A tube 31 is rotatably mounted in the plates 25, 26 and on a support 30 and houses a slidably mounted and spring-loaded thrust member 38 which projects through a slot 35 in the tube and co-operates with a rod 42 associated with the push-button 43. The rod is rotatable by the key of a barrel lock 45 disposed in the push-button. A cam 46 is fixed to the inner end of the tube 31 and recesses 49 and 50 on the cam cocperate with a spring-loaded sliding member 52. An aperture 53 engages with a finger 54 on an extension of the lever 29 by which the thrust member 38 is moved by the lever between its operative and latch locking positions. In operation actuation of the press-button 43, Fig. 4, engages the thrust member 38 with the tab 19 on the latch bolt to disengage the ncse 17 of the bolt from the keeper 7 and allows the door to be pulled to open position. The latch may be operated by the inside door handle, which pivots lever 28 in the direction of arrow f2, Fig. 3, so that a projection 57 engages the tab 20 on the bolt. The latch may be locked by the interior push-button which rotates the thrust member 38, through the lever 29 and cam 46, to the position shown in Fig. 8 in which the push-button 43 becomes inoperative. If the door is slammed closed with the latch in locked condition, the keeper 7 rotates the latch bolt 15 so that the tab 20 thereon rotates the lever 29 and hence the cam 46 and thrust member 38 to the unlocked position of Fig. 3. The arrangement of the levers 28 and 29 is such that if the lever 28 is moved in the opposite direction to the arrow f2, the lever 28 engages an abutment 56 on lever 29 to move the latter and hence the cam 46 and the thrust member to the locked position. In a modification, Figs. 11-13 (not shown), the arm of the lever 29 and the interior push-button are dispensed with, the modified lever being actuated indirectly through a modified form of the lever 28 by a push-button connected directly to an extension of the cam 46. The arrangement of the levers is such that to open the latch it is necessary to bring the cam to its unlocked position by means of the push-button, or by rotating the tube 31 by means of the key. In another modification, Fig. 14 (not shown), the thrust member 38 is mounted for limited rotational movement relative to the tube 31 and the tubular part of the thrust member is cylindrical in cross section. In a further modification, Fig. 15 (not shown), the latch cover is provided with a flange adjacent the tab 19 to prevent the thrust member from being inadvertently placed to the rear of the tab. In all arrangements, those parts of the latch case to be applied against the wall of the door or its frame are provided with small projections or spikes formed by knurling the metal. Specification 822,405 is referred to.