Patent GB-814816-A (GB)
Title: Improvements in or relating to locking mechanism for a safe
IPC: E05B65/00
Filed: 1956-04-04
Abstract: 814,816. Safes; multiple fastenings; sliding bolts: SPERRY RAND CORPORATION. April 4, 1956 [Nov. 7, 1955], No. 10311/56. Class 44 A locking mechanism mountable on a safe door includes a bolt engageable in a corresponding recess in the safe casing and means for advancing the bolt into and retracting it from the recess, the mechanism also including blocking means adapted in the locked position of the safe door and upon application of force to the outer end of the bolt tending to retract it, to prevent retraction of the bolt, the blocking means not forming part of the means for advancing the bolt. The safe has outer and inner walls 10, 11, Fig. 1, with intervening fire-proof cement 12 and recesses 13 to receive sliding bolts 31 connected by links to the ends of crossed-arms 43, 48 pivoted at 45 on a support plate 18, welded to the inner face 17 of the safe door. The arm 43 is connected to a slide 27 having a slot 28 engaging a pin 29 on the plate 18. The slide 27 is pivoted at 26 to an arm 25 fixed on a shaft 24 passing through the plate 18 and the door and carrying at its outer end a handle 23. A combination lock 19, mounted on the plate 18 and operable by a shaft 22 having a knob 21, has a bolt 20 adapted to engage behind a flange 30 on the slide to retain it in the shot position. The upper and lower bolts 31 are connected by links 49 and 50 to the arm 48 and are each provided with a chamber 64 in which is slidable a plate 67 having a stem 68 tapered at its end and passing through an aperture 65 to engage. the inner tapered ends of a pair of plugs 69 slidable in a transverse bore in the bolt. If an attempt is made to force the bolt by drilling through the safe wall and applying force to the bolt end by a tool, the plate 67 is slid into the bolt 31 to move the plugs 69 outwardly to engage the edge of the bolt aperture 14 in the wall 11 and thus lock the bolt against further retraction. The right hand bolt 31 is pinned at 33 to an extension plate 32 pivoted at 62 to a link 47 pivoted at 46 to the cross-arm 43. The pivot 62 is disposed below the centre line of the bolt 31 and if an attempt is made to force the bolt the plate 32 and link 47 pivot relatively to each other so that the inner end of the plate 32 engages a blocking flange 63 in the plate 18 and locks the bolt against further retraction. The left hand bolt 31 also has an extension plate 32 provided with a pair of pins 34, 35. The pin 34 engages between the forked end of a link 36 pivoted at 37 to the slide 27 whilst the pin 35 engages a slot 39 in the link 36. Moreover a pin 40 engages an open-ended slot 41 in the slide 27 and the link 36 is pivoted at 42 to the cross-arm 43. The upper thin arm 38 of the fork engages a flange 53 extending from a latch plate 54 slidable on the plate 18 and having a toe 55 engaging in a notch 56 in a sliding plate 57 slidable in a cover plate 57' welded to the plate 18. If the bolt 31 is forced inwardly the pin 34 causes the thin arm 38 to move upwardly to lift the flange 53 and thus the latch plate 54 to release the plate 57 which is then moved to the right by a spring 59 to obstruct the movement of the link 50 and thus prevent retraction of all of the bolts.