Patent GB-770144-A (GB)
Title: Improvements relating to door locks
Inventor: JOB REGINALD
IPC: E05B65/22
Filed: 1955-06-22
Abstract: 770,144. Door latches. MORRIS MOTORS, Ltd. June 22, 1955, No. 18022/55. Addition to 612,984. Class 44. A looking - mechanism of the sliding latch bolt type for motor vehicles has a bolt-actuating member 9 which is pivotally mounted on a sliding bolt 3 or on a member rigid therewith and which is normally engageable by an outside handle 13 but is coupled to an inside handle (not shown) by a pin- and-slot connection 15, 16 which is so arranged that during retraction of the sliding bolt, the boltactuating member is constrained to pivot until it becomes latched by a detent lever 27 which then retains it in a position in which it is not engageable by the outside handle, the detent lever being releasable by a key-operated lock (not shown) to permit the bolt actuating member to return pivotally to the setting in which it is engageable by the outside handle. With this arrangement the closing of the door causes it to become locked automatically and is a modification of the invention disclosed in the parent Specification in which the mechanism was locked by the inside handle. As shown, the latch bolt 3 is attached to a plate 2 which is slidably mounted on a back-plate 1. The bolt 3 and plate 2 are retractable against the action of a spring 4 which surrounds a rod 5 which is attached to the plate 2 and which is slidable in a block 6 fixed to the back-plate 1, the travel of the plate 2 being limited by a slot 7 which engages a pin 8 fixed to the back-plate 1. The bolt-actuating member 9 is pivotally mounted on the plate 2 by a pivot 10 and is urged in a clockwise direction by a spring 24. The bolt is retracted by the outside handle 13 through an arm 12 which engages a nose 11 on the boltactuating member 9. The tail of the boltactuating member is connected by the pin-andslot connection 15, 16 to a link 17 which at its other end is pivotally attached to a lever 18 operable by the inside door handle and the lever 18 is located in the position shown in Fig. 1 by a pin 19 which is slidable in a slot 20 formed in a mounting-plate 21, the pin being urged upwardly by a spring 22 into engagement with a cam-like notch 23 in the lever 18. When the door is open the locking mechanism is normally in the condition shown in Fig. 1 and upon closing the door the sliding bolt 3 is retracted when it encounters the striker and the boltactuating member 9 moves back together with the plate 2 and the member 9 is caused to turn about its pivot 10 against the action of its spring 24 since the link 17 prevents movement of the pin 15 on the member 9. The pivotal movement of the member 9 causes a claw 26 on the detent lever 27 to latch the member 9 so that it cannot return to its original position when the plate 2 moves back after the latch bolt has cleared the striker. This movement of the member 9 raises its nose 11 above the path of movement of the arm 12 of the outside door handle 13 which consequently is no longer effective to unlock the door. In this condition the latch bolt 3 can be moved from the inside to open the door through the link 17 and the lever 18 but to open the door from the outside the detent lever 27 is disengaged from the member 9 by means of the key-actuated lock, which is of the barrel type, through a lever 34 and link 35. The spring 24 then returns the lever 9 to the position in which its nose 11 can be engaged by the arm 12 on the outside handle 13.