GB2071197A

GB2071197A - Anti-theft lock

Info

Publication number: GB2071197A
Application number: GB8104059A
Authority: GB
Original assignee: Sodex Magister Societe dExploitation des Brevets Neiman SA
Current assignee: Sodex Magister Societe dExploitation des Brevets Neiman SA
Priority date: 1980-03-07
Filing date: 1981-02-10
Publication date: 1981-09-16
Also published as: AR225658A1; ES256932U; BR8101286A; ES256932Y; PL230017A1; DE8104059U1; FR2477619B1; JPS56139370A; DE3105390A1; PL128623B1; FR2477619A1; IT8120174A0; DD156727A5; GB2071197B

Abstract

A lock cylinder (1) is fast in rotation with a mild steel disc (6) which can slide axially in relation to the cylinder (1), and the lock body (3) carries an electric coil (8) concentric with the cylinder (1) and capable of being supplied by a current source in such manner as to attract the said disc (6) against the action of a return spring (9) which returns the disc (6) towards a position in which a locking member (12) of the disc (6) cooperates with a complementary member (11) fast with the body (3), in the locking angular position of the cylinder (1). <IMAGE>

Description

SPECIFICATION Anti-theft lock The invention relates to a cylinder lock of the type comprising a cylinder pivoting in a bore of a body by means of a controlling key.

The use of such locks are greatly various but it can be useful if their actuation is tied not only to the presence of the key in the lock but also to another external condition In this case it has been proposed to block the lock cylinder by the action of an electro-magnet blade which comes to engage in a notch in the cylinder. The cylinder is liberated when the blade is in the opposite position. These known devices possess the drawback of not permitting unlocking of the lock if the electro-magnet or its supply should be defective. Moreover they are bulky and costly, limiting their utilisation.

The present invention aims at reducing the drawbacks of the known devices for blocking the cylinder of a lock.

According to the invention there is provided a cylinder lock of the type comprising a housing body, a cylinder rotatable in a bore in said housing body by means of a controlling key, a mild steel disc attached to the cylinder which can slide axially in relation to the cylinder, a locking member on said disc, a member complementary to said locking member and fast with the housing body for co-operation with said locking member to lock said cylinder against rotation, a return spring in engagement with said disc to urge the latter in a direction to effect engagement of the locking member and complementary member, and an electric coil mounted within said housing body concentric with the cylinder and capable of being supplied by a current source in such a manner as to attract the said disc against the action of said return spring.

The invention will be clearly understood on reading of the following description given with reference to the accompanying drawing, wherein: FIGURE 1 is a diagrammatic axial sectional view, partly in elevation, of a lock according to one example of embodiment of the invention, in the position where the cylinder and the disc are locked; FIGURE 2 is analogous with Figure 1, the key being introduced into the cylinder and the disc being in the unlocked position; FIGURE 3 is analogous with Figure 1 , an incorrect key being introduced into the cylinder, and FIGURE 4 is analogous with Figure 2, but in an unblocking position in the case of non-function of the blade-coil system.

In the example as represented the lock is of the "piston" or "pin" type, but the invention is applicable in the same manner to locks called "blade"-type. The lock comprises a cylinder 1 rotatable in a bore 2 of a body 3 by means of a key 4. The head of the cylinder 1 comprises a noncircular zone 5, for example of square section, on which there can slide, parallel with the axis of the lock, a mild steel disc 6 provided with a central cut-out 7 of form matching that of the zone 5, so that the disc 6 remains fast in rotation with the cylinder 1.

In the body 3 of the lock there is housed an electric coil 8 concentric with the cylinder 1 and mounted opposite to the disc 6. The coil 8 can be supplied by an exterior source (not shown) so as to attract the disc 6 against the action of a return spring 9. When the coil 8 is not supplied the disc 6 is thrust back by its spring 9 towards a wall 10 fast with the body 3. The wall 10 carries a stud 11 which penetrates into a notch 12 of the disc 6 when the cylinder 1 is in the locking angular position as represented in the various Figures.

When the key is withdrawn from the cylinder 1 and the coil 8 is not supplied (Figure 1), the cylinder is subjected simultaneously to blocking by its pistons (or its blades in the case of a blade type lock) and to blocking by the disc 6 held fast in rotation by the stud 11 lodged in the notch 12.

Thus there is a double locking of the cylinder since the disc 6 is fast in rotation with the cylinder 1.

If the appropriate key 4 is introduced into the cylinder 1 and if the coil 8 is supplied (Figure 2), the cylinder 1 is unlocked and can rotate under the action of the key 4. As soon as it has left its locking position it can continue to rotate freely, even if the coil ceases to be supplied, since the notch 1 2 is no longer facing the stud 1 so that the disc 6 comes to abut with its solid peripheral part against the stud 11, without impeding rotation.

In the case where an incorrect key 4' is introduced into the cylinder 1 , the coil 8 not being supplied (Figure 3), the cylinder is still subject to double locking as in the case of Figure 1. If an attempt is made to unblock the cylinder 1 by action upon its pistons by means of tools, for example by the dishonest break-in method known under the name of Hobb's method, the cylinder 1 remains blocked because the disc 6 remains locked by the co-operation of its notch 12 with the stud 11.

In Figure 4 there is represented a possibility of unblocking the cylinder 1 in the case where there is a defect in the system comprising disc 6 and coil 8, in its supply or in the controlling of this supply. The cylinder 1 can slide parallei with its axis against the action of the spring 9 in the presence of the key 4. This possibility of sliding of the cylinder 1 is usable only with a piston lock, since the construction of a blade-type lock would permit sliding of the cylinder even with an incorrect key or even without a key. The cylinder 1 carries a collar 13 pressing upon the face of the disc 6 opposite to the coil 8.

Insertion of the key 4 pushes the cylinder 1 back inwards, the collar 13 pushing the disc 6 until it abuts on the coil 8, so that the notch 12 departs from the stud 11 and the cylinder 1 can be rotated by means of the key 4. As soon as the cylinder has left its locking angular position, the user can release the axial pressure upon the key, the solid part of the periphery of the disc 6 coming to abut against the stud 11, without impeding rotation. In the presence of an incorrect key 4' (Figure 3) or in the absence of a key (Figure 1), the cylinder 1 is blocked axially by its pistons and thus cannot be pushed back axially to try to free the disc 6.

The lock according to the invention is particularly suitable for electric remote control since the double locking of the cylinder 1 increases the security of the lock. It can be applied to a door lock or anti-theft device lock of a vehicle.

Of course the disc 6 could comprise a radial stud and the wall 10 could comprise a notch facing the stud, for the locking angular position of the cylinder.

Claims

1. A cylinder lock of the type comprising: a) a housing body, b) a cylinder rotatable in a bore in said housing body by means of a controlling key, c) a mild steel disc attached to the cylinder which can slide axially in relation to the cylinder, d) a locking member on said disc, e) a member complementary to said locking member and fast with the housing body for co-operation with said locking member to lock said cylinder against rotation, f) a return spring in engagement with said disc to urge the latter in a direction to effect engagement of the locking member and the complementary member, and g) an electric coil mounted within said housing body concentric with the cylinder and capable of being supplied by a current source in such a manner as to attract the said disc against the action of said return spring.

2. A lock as claimed in claim 1, wherein the locking member and complementary member comprise an axial notch on the disc and an axial stud fast with the housing body, said notch and stud being opposite each other in the locked position of the cylinder.

3. A lock as claimed in claim 1, wherein the locking member and complementary member comprise an axial stud on the disc and an axial notch fast with the housing body, said stud and notch being opposite each other in the locked position of the cylinder.

4. A lock as claimed in claim 1, wherein the lock is of the piston type and the cylinder is mounted for inward sliding, the said cylinder carrying a collar pressing upon the disc on its face opposite to the electric coil.

5. A cylinder lock substantially as described herein with reference to the accompanying drawings.