GB472446A - Improvements in locks - Google Patents

Abstract

472,446. Latches. MOFFITT AUTOMATIC LOCK CO., Ltd. Sept. 1, 1936, No. 23968. Convention date, Oct. 21, 1935. [Class 44] A spring-shot door latch which is retained in withdrawn position when door is opened, and is released when door is closed by means of a slidable release rod projecting through the hinged edge of the door to co-operate with the fixed door post, comprises a sliding rod 1 with conical bolt head 2 co-operating with a conical keeper socket 3 to prevent rattle, a compression spring 5 urging the bolt to shot position, a handle spindle 11 with arm 10 normally held in the position shown by a tension spring 20, the arm carrying a pawl 18 engaging a shoulder 19 on rod 1 so that the bolt is retracted by clockwise rotation of spindle 11, and a retaining pawl 21 co-operating with shoulder 24 on rod 1 to hold the bolt retracted when the door is opened. Pawl 21 is pivoted to the casing at 22 and is pivotally connected to a rod 23 loosely guided in a fixed member 17 so as to be capable of sliding and slight rocking in a vertical plane to allow for pivotal movement of pawl 21. A compression spring 34 normally urges rod 23 to the right and pawl 21 to anticlockwise rotation to engaging position. A release rod 25 is urged by spring 27 to project its end from the hinged side 26 of the door, but is held in the position shown, with spring 27 compressed, by co-operation of the end of rod 25 with a fixed stop 33 in the door post 32. Rod 25 has a pivoted extension 30 held in alignment by a flat spring 31 so that its free end abuts against the end of rod 23 and holds pawl 21 in the retracted position shown with spring 34 in compression. When spindle 11 is operated to open the door, a cranked lever 37, pivoted at 38, is rocked clockwise by link connection 41 with arm 10 so that a pin 40 on the lever knocks up the free end of member 30 and allows spring 34 to move pawl 21 into engaging position, to hold 'bolt retracted. When the door is opened spring 27 projects rod 25 through the edge of the door and spring 31 restores member 30 to alignment behind rod 23. Closing the door restores the parts to the position shown. The Specification as open to inspection under Sect. 91 comprises also a modification in which members 30, 34, 37, 41 are omitted, rod 25 being pivotally connected to rod 23. This subject-matter does not appear in the Specification as accepted.