Lock with burglar-proof locking bolt, particularly for safes

Abstract: The lock with burglar-proof locking bolt, particularly for safes, comprises a locking bolt (3) slideable between a position in which it engages the selvage (8) in the abutment jamb (9) of the door of the safe and a position in which it engages a seat (7) in the lock stile (1) of the door, the bolt being loosely coupled to a lever (4) which is articulated to a movable element(2) actuated by the lock and which is provided with a tooth (10); mutual contact planes (11,13) are defined in the locking bolt and in the lever and are inclined with respect to the sliding axis of the locking bolt so as to produce, when the locking bolt is forced to retract into the seat, the oscillation of the lever into the position in which the tooth interacts with the edge of the seat.

Description: The present invention relates to a lock, particularly for safes, with burglar-proof locking bolt. As is known, attempts to crack safes, particularly recessed ones, are aimed at making the locking bolt retract into the lock by axial forcing with appropriate safe-cracking tools. The aim of the present invention is therefore to provide a lock equipped with a locking bolt which, if forced, causes the engagement of a locking system which stops all axial movement of said locking bolt for retraction into the lock. This aim is achieved, according to the present invention, with a lock with burglar-proof locking bolt, particularly for safes, comprising a locking bolt slideable between a position in which it may engage a striker in the abutment jamb of a safe door and a position in which it retracts into a seat in the lock stile of a door, the bolt being loosely coupled to a lever which is articulated, at one end, to a movable element actuated by the lock and which is provided with a laterally protruding tooth at the opposite end, mutual contact planes being defined in said locking bolt and in said lever, said planes being inclined with respect to the sliding axis of the locking bolt so as to produce, when the locking bolt is externally forced to retract into said seat, deflection of said lever into a position in which said tooth abuts against the mouth of said seat so as to lock the locking bolt in the striker engagement position. The details of the invention will become apparent from the detailed description of a preferred embodiment of the lock with burglar-proof locking bolt, illustrated only by way of non-limitative example in the accompanying drawings, wherein: figure 1 is a view of the opening side of a safe, with a cutout line which illustrates, in enlarged scale, a locking bolt according to the invention in the position in which it opposes forcing; and figure 2 is a view, similar to that of figure 1, with the locking bolt in the opening position. With reference to the above figures, the reference numeral 1 indicates the lock stile of the door of a safe, proximate to which a known lock, of the key or combination type, is mounted; only the tang 2 of said lock, which actuates one or more locking bolts 3, is shown in the drawing. The locking bolt 3 is constituted by a cylindrical barrel which is coupled to a lever 4 which is articulated to the tang 2 by means of a threaded bolt 5. The reference numeral 6 designates a rod to which any additional locking bolts are connected; said rod is fixed to the tang 2 at right angles to the sliding direction of said tang. The locking bolt 3 is guided in a seat 7 of the lock stile 1 so as to engage, when the safe is in closed position, a selvage 8 defined in the abutment jamb 9 of the door of said safe. The free end of the lever 4 has a tooth 10, which protrudes laterally upward from the upper edge of the lever, and an oblique lower edge 11. The lever 4 is inserted in a slot 12 which partially cuts the locking bolt 3 along a diametrical axial plane, forming an oblique bottom 13 which acts as abutment for the oblique edge 11 of the lever 4. The locking bolt 3 and the lever 4 are mutually connected by means of a pin 14 which is diametrically inserted in the locking bolt 3 at right angles to the plane of the slot 12. The pin 14 passes through a slot 15 of the lever 4 whose dimensions are such as to allow the lever 4 to perform axial strokes with respect to the locking bolt 3 and oscillate by an extent sufficient to allow the tooth 10 to leave the slot 12. When the lock is actuated in closure position, the lever 4, by moving within the seat 7, acts against the bottom 13 of the slot 12 of the locking bolt 3, which is therefore pushed into the position in which it engages the selvage 8. During opening, the locking bolt 3 is returned into the seat 7 after the lever 4 has covered an idle stroke portion defined by the play with which the pin 14 is inserted in the slot 15. If an attempt to force the locking bolt 3 to retract into the seat 7 is performed while the safe is in closed position in order to unlawfully open the safe, the engagement between the inclined planes of the edge 11 and of the bottom 13 causes the lifting of the lever 4, whose tooth 10 arranges itself in abutment against the edge of the seat 7, preventing the further movement of the locking bolt (see figure 1). A substantial advantage of the invention is constituted by the fact that the forcing action applied to the locking bolt is not transmitted to the tang 2 and thus to the lock, which therefore suffer no damage at all and maintain their full efficiency. It should be noted that the locking bolt 3, by virtue of its structure, and the lever 4, by being protected by the locking bolt, also do not suffer appreciable deformations, so that the safe remains accessible even after the forcing attempt. Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly such reference signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference signs.

Claims: Lock with burglar-proof locking bolt, particularly for safes, comprising a locking bolt (3) slideable between a position in which it may engage a striker (8) in the abutment jamb (9) of a door of a safe and a position in which it retracts into a seat (7) in the lock stile (1) of a door, the bolt being loosely coupled to a lever (4) which is articulated, with one of its ends, to a movable element (2) actuated by the lock and which is provided, at the opposite end, with a laterally protruding tooth (10), mutual contact planes (11, 13) being defined in said locking bolt (3) and in said lever (4), said planes being inclined with respect to the sliding axis of the locking bolt (3) so as to produce, when the locking bolt (3) is externally forced to retract into said seat (7), deflection of said lever into a position in which said tooth (10) abuts against the mouth of said seat (7) so as to lock the locking bolt (3) in the position in which it may still engage a striker (8). Lock according to claim 1, characterized in that said lever (4) is inserted in a slot (12) which cuts the locking bolt (3) along a diametrical axial plane, forming an oblique bottom (13), said lever (4) having an oblique edge (11) suitable to abut against said oblique bottom (13) if the locking bolt (3) is externally forced, in order to cause deflection of said lever (4) into the position in which said tooth (10) engages the mouth of said seat (7).

Inventors: ERRANI DEO, ERRANI, DEO
Applicants: IMP IND METALMECC PERUGIA, INDUSTRIE METALMECCANICHE PERUGIA I.M.P. S.P.A.
Application year: 1992
Main classification: E05B65
IPC codes: E05B65