FIELD OF THE INVENTION

The present invention relates to locking apparatus generally and more particularly to an anti-snap cylinder lock assembly with a pre-formed break region that breaks upon an attempted unauthorized forced entry.

BACKGROUND OF THE INVENTION

Vandals have attempted to break cylinder locks installed in doors by grabbing a portion of the cylinder lock, which protrudes outwards from the outside face of the door, with a tool such as locking pliers. By applying sufficient and violent shearing force on the lock, the vandal can break off (shear off, or as termed in the industry, snap off) a portion of the cylinder lock. The result is the cylinder lock is either destroyed or easily removed, and the vandal can open the door, or at least gain access to the inner workings of the lock to open the door.

Attempts have been made to defeat such unauthorized intrusions. One example is called an anti-snap cylinder lock, wherein the cylinder lock is purposely pre-formed with a notch that weakens the body of the cylinder lock and ensures the cylinder lock will break along this notch, which is strategically positioned to allow breaking that does not harm the operation of the cylinder lock. The expected result is the cylinder lock is not destroyed; the vandal cannot gain entry and the cylinder lock perhaps remains operable. Examples of such locks are described in Italian patent document ΓΓΒΟ2000-00425 to Corbin and Bulgarian Patent BG62182.

However, it has been found that even after breaking along this notch, which is parallel to the face of the cylinder lock plug, there is sufficient material left on the cylinder lock which can still be grabbed by a tool (e.g., lock pliers) and the vandal can further break the cylinder lock and gain entry.

SUMMARY OF THE INVENTION

The present invention seeks to provide a novel anti-snap cylinder lock assembly with a pre-formed break region that breaks upon an attempted unauthorized forced entry, which solves the problem of the prior art, as is described more in detail hereinbelow.

There is thus provided in accordance with an embodiment of the present invention an anti-snap cylinder lock assembly including a plug having a keyway and arranged for movement in a bore formed in a cylinder lock body, wherein the cylinder lock body is formed with pre-formed breaking structure, which when broken, forms a broken surface which is not perpendicular to a longitudinal axis of the cylinder lock body or of the plug. Non-limiting embodiments of the invention include one or more of the following features.

The pre-formed breaking structure may include at least one notch. The at least one notch may be positioned with respect to the longitudinal axis such that the broken surface tapers to a narrower width than the cylinder lock body in a direction towards an outer face of the cylinder lock body. The at least one notch may include a pair of notches angled at a non-zero angle with respect to the longitudinal axis. The notches may meet at an apex.

The at least one notch may include notches which are contiguous with another. The at least one notch may include notches which are axially spaced from one another and wherein an outer notch extends over more of a periphery of the cylinder lock body than an inner notch. The broken surface may be non-perpendicular to the longitudinal axis at more than one plane. The at least one notch may be curved (e.g., convex or concave) with respect to the longitudinal axis.

The plug may include locking elements that are operable even after the preformed breaking structure breaks.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be understood and appreciated more fully from the following detailed description, taken in conjunction with the drawings in which:

Figs. 1A-1C are simplified side-view, top-view and perspective illustrations, respectively, of an anti-snap cylinder lock assembly, constructed and operative in accordance with an embodiment of the present invention;

Figs. 2A and 2B are top-view and perspective illustrations, respectively, of the anti-snap cylinder lock assembly after breaking ("snapping") along pre-formed breaking structure to form a broken surface;

Figs. 3 A and 3B are simplified top-view and perspective illustrations, respectively, of an anti-snap cylinder lock assembly, constructed and operative in accordance with another embodiment of the present invention;

Figs. 4A and 4B are simplified top-view and perspective illustrations, respectively, of an anti-snap cylinder lock assembly, constructed and operative in accordance with yet another embodiment of the present invention;

Figs. 5A and 5B are simplified perspective and side-view illustrations, respectively, of an anti-snap cylinder lock assembly, constructed and operative in accordance with still another embodiment of the present invention; and Fig. 6 is a simplified perspective illustration of an anti-snap cylinder lock assembly, constructed and operative in accordance with another embodiment of the present invention.

DETAILED DESCRIPTION OF EMBODIMENTS

Reference is now made to Figs. 1A-1C, which illustrate an anti-snap cylinder lock assembly 10, constructed and operative in accordance with a non-limiting embodiment of the present invention.

In the illustrated embodiment, lock assembly 10 includes a plug 12 having a keyway 14 for inserting therein a key (not shown). Plug 12 is arranged for movement in a bore 18 formed in a cylinder lock body 20. In Figs. 1A-1C, cylinder lock body 20 is a European profile double cylinder lock with two bodies 20 for actuating a common cam 21, but the invention is not limited to this.

The plug 12 and/or cylinder lock body 20 is formed with pre-formed breaking structure 22, which when broken, forms a broken surface 23 (Figs. 2A and 2B) which is not perpendicular to a longitudinal axis 24 of cylinder lock body 20 or of plug 12. In the illustrated embodiment, longitudinal axis 24 is common to both cylinder lock body 20 and plug 12, but the invention can be carried out wherein cylinder lock body 20 and plug 12 have different longitudinal axes and the broken surface 23 is not perpendicular to either or both of these longitudinal axes.

In accordance with an embodiment of the present invention, the pre-formed breaking structure 22 is formed on both cylinder bodies 20 of the double cylinder lock. Alternatively, the pre-formed breaking structure 22 is formed on only one of the cylinder bodies 20 of the double cylinder lock.

The pre-formed breaking structure 22 may include at least one notch 26. The term "notch" encompasses a groove, ridge, recess, cutout and the like, which may be cut all the way through the thickness of the cylinder lock body 20 at select portions thereof and partially through the thickness at other portions thereof, or just partially through the thickness at all points. The at least one notch 26 may be positioned with respect to the longitudinal axis 24 such that the broken surface tapers to a narrower width than the cylinder lock body 20 in a direction towards an outer face of the cylinder lock body 20, as seen clearly in Figs. IB, 1C, 2A and 2B. The at least one notch 26 may include a pair of notches 26 angled at a non-zero angle (acute, right or obtuse angle) with respect to longitudinal axis 24. The notches 26 may meet at an apex 28, and may be contiguous with another. The broken surface 23 (in all embodiments of the invention) is very difficult, if not impossible, to grasp with a tool, such as locking pliers, and therefore is significantly more difficult to defeat by vandals than prior art anti- snapping cylinder locks.

Reference is now made to Figs. 3A-3B. The one or more notches may include notches 30, 32 and 34 which are axially spaced from one another. The outer notch 30 extends over more of a periphery of the cylinder lock body 20 than middle inner notch 32, which extends over more of a periphery of the cylinder lock body 20 than innermost notch 34.

Reference is now made to Figs. 4A-4B. In this embodiment, similar to that of Figs. 3A-3B, the one or more notches may include fully cut-out regions (notches) 40, 42 and 44 which are axially spaced from one another. The outer notch 40 extends over more of a periphery of the cylinder lock body 20 than middle inner notch 42, which extends over more of a periphery of the cylinder lock body 20 than innermost notch 44.

Reference is now made to Figs. 5A-5B. The pre-formed breaking structure 22 and the broken surface 23 can be non-perpendicular to the longitudinal axis 24 at more than one plane, which may increase the difficulty of grasping with a vandalizing tool.

Reference is now made to Fig. 6. The at least one notch 26 may be curved (e.g., convex or concave) with respect to the longitudinal axis 24. The plug 12 (in all embodiments of the invention) may include locking elements 60 (e.g., plug pins) that are operable even after the pre-formed breaking structure breaks.

The scope of the present invention includes both combinations and subcombinations of the features described hereinabove as well as modifications and variations thereof which would occur to a person of skill in the art upon reading the foregoing description and which are not in the prior art.