GB782743A - Improvements relating to locks - Google Patents

Abstract

782,743. Locks. LOWE & FLETCHER, Ltd. May 13, 1955 [May 13, 1954], No. 13987/54. Class 44 Relates to a look of the kind comprising a bolt movable between locking and unlocking positions, an abutment on or operatively associated with the bolt for corresponding movement therewith and a plurality of displaceable latching elements coacting with the abutment to retain the same in at least a locking position, such elements being displaceable individually by respective formations on a key to a releasing position in which they are freed from the abutment to an extent permitting the bolt to be moved by further movement of the key from its locked to its unlocked position. According to the invention, the latching elements have operatively associtated with them two or more master release elements which are separate from the latching elements and which both or all co-operate with the latching elements to displace the same to the releasing positions through the intermediary of a part which requires that both or all the master release elements shall be displaced by master formations on a master key before the latching elements attain their releasing positions. As shown, in which a bolt 14 is slidably guided by a pin 18 extending into a slot 19 of the bolt tail and in which movement of the bolt is ccntrolled by spring loaded latching elements 28 pivoted about the pin 18 and displaceable to clear an abutment 32 on the bolt by a formation on a key 23 carried by a rotatable key guide 21, additional levers 36 pivoted about the pin 18 are provided at the penultimate positions of the latching elements 28 and are displaceable by a formation 38 on a primary master key 39. A pin 40 extends through the elements 28 and levers 36, such that the elements 28 may be displaced to their releasing positions by a pass key 23, the levers 36 being allowed to remain in their undisplaced positions, or such that levers 36 may be displaced by the key 39 to effect displacement of the elements 28 by means of the pin 40. The levers 36 may be provided with shoulders 43 which co-operate with abutment 32 on the bolt, so that the levers 36 are displaced to free the bolt when the elements are displaced by a pass key. A secondary master key may be provided with formations to displace the levers 36 in all locks of a series, whilst primary master keys may be used only to operate locks of a particular group in the series.