GB902286A - Improvements relating to locks - Google Patents

Abstract

902,286. Key locks. MORAN & CO. (ENGINEERS) Ltd., F. S. Dec. 1, 1960 [Oct. 8, 1959], No. 34080/59. Class 44. A lock for a manhole cover or other similar heavy closure comprises two latch members 6, 7 which are pivotable independently about a spindle 8 mounted between two flanges 9, 10 depending from the cover 2, and adapted to engage under a lip 13 on the adjacent inner wall of a channel-section, rectangular frame 1 to which the cover is pivoted at the side remote from the latch members 6 and 7. Each latch member 6, 7 has a plate 14, 15 integral therewith, the weight of which urges the corresponding latch into engagement with the rim 13, and each plate comprises a slot 20 or 21 for engagement by vertically-spaced pins 24, 25 extending laterally from the shank 22 of a key which is inserted into the space between the two plates 14, 15. The key-hole opening 17 in the cover comprises a circular aperture and a slot extending radially therefrom, so that after sliding the lowermost pin 25 through the aperture, the key must be given half a turn before it can be fully inserted in the lock, the pins 24, 25 then engaging their respective slots 20, 21. Thus by then raising the key, the latches are swung clear of rim 13 and the cover 2 may be lifted, and on closing the cover and removing the key, the weights of the plates 14, 15 will cause the latches to resume their locking positions. A crossmember 16 secured to the depending flanges 9, 10 limits both the downward movement of the plates 14, 15 and the upward movement of the latches 6, 7. The cover may be opened or closed from the inside without using the key, opening being effected by pushing the plates 14, 15 upwards, and closing being effected by the co-operation of cam surfaces 11A, 12A on the latches with the sloping surface of the lip 13. A hinged cover (not shown) is provided for the key-hole opening.