There are quite a few patents/patent applications in the technical field of the present invention. One of those is EP 1 091 058 B1. According to the disclosure provided therein, two cylindrical half-housings comprise reinforcing members, a part of which is within a flange extending on one side of the cylinder lock and another part is in the region of said bridge-like portion so as to surround said lock fixing hole. The most apparent drawback of this arrangement is that it further weakens the bridge-like portion by necessarily enlarging the screw hole so as to comprise the reinforcing elements therein. In this respect, it eases a rupture in the region at which said reinforcing elements surround the fixing hole.

As is explained in EP 1 091 058 B1 , the reinforcing elements are not for preventing a flexural rupture of the lock body at the bridge-like portion. Rather, this rupture is considered as inevitable and the device is arranged so that once the lock body has been broken at the bridge-like portion, the two half-housings in which it is divided cannot be separated from each other. Said reinforcing elements might indeed prove difficult to be separated from each other. This, however, does not signify that said elements can not be separated from the cylindrical half-housing on the lateral surface of which they are embedded. Indeed this can be easily done by applying a lateral force, as experience has shown, by a levier rod or a charging bar. When one of the two parts of the lock is bent, then said elements are likely to disengage and the two parts of the lock come apart once the weakest line is broken. Needless to mention, the worst case is that the two lock not only breaks into two pieces but said two pieces on the inner and outer side of the door fall respectively inside and outside of the door and the burglar has the chance to freely rotate the locking pawl with a simple tool.

Additionally, in case one of the reinforcing elements is detached from the half- housing it is embedded in, said cylindrical half-housing may then be easily removed out of its base and although the other half-housing and both of the reinforcing elements are still in place and are still attached to each other, the slot in which the pawl resides to operate the door lock may easily be accessible by means of any sharp tool, such as a screwdriver or a strong wire for instance, to completely release

the lock.

The reinforcing system, which consists of two reinforcing members according to the present invention, is advantageous in that said members can be removed neither from the half-housings to which they are fixedly attached nor from each other due to a high tensile strength element in between. In case a rupture takes place in said bridge-like screw hole portion, connection structure between two reinforcing members on separate half-housings serves to the purpose of substantially retarding separation of the two members due to the elastic and energy dissipating structure of said connection.

Objects of the Invention

In view of the problems with regard to the prior art disclosed above, one of the objects of the present invention is to prevent separation of the two half-housings of the cylinder assembly without causing further weakening of the already fragile bridge-like screw hole portion so as to the same as least as possible.

Another object of the present invention is to provide a cylinder assembly comprising a reinforcing system with two reinforcing members which can not be separated from the half-housings.

Further an object of the present invention is to provide a cylinder assembly comprising a reinforcing system with two reinforcing members which can not be separated from each other.

Summary of the Invention

The objects of the invention are achieved through use of a reinforcing system comprising two reinforcing members in the form to incorporate pins embedded in the bottom surface of the lock assembly. Said reinforcing members, located at opposite sides of the bridge-like screw hole portion, are connected to each other by means of a non-extensible and hollow fixing device, fixedly attached to the pin heads and extending in the form of two arms around each pin. Additionally, an extensible element is laid in the form of a high tensile strength structure in between the two pin heads and within the empty surface encircled by said non-extensible hollow fixing device. The positions at which the two pins are located fall outside the space defined by the projection lines of the vertical borders of the notch within which the pawl is situated.

Brief Description of the Figures

Accompanying drawings are given solely for the purpose of exemplifying a cylinder assembly whose advantages over prior art were outlined above and will be explained in detail hereinafter:

Fig. 1 demonstrates a perspective side view of the lock cylinder assembly in which the reinforcing system with the two pin heads, the non-extensible hollow fixing device and the high tensile strength connection structure are shown.

Fig. 2 demonstrates the same view in Fig. 1 with the pins being shown in the body of the lock.

Fig. 3 is a side view of the lock assembly.

Fig. 4 is a top view of the lock assembly.

Fig. 5 demonstrates the reinforcement elements in the form apart from the lock assembly.

Detailed Description of the Invention

Referring now to the figures outlined above, the lock assembly (11) typically comprises a longitudinally extending cylindrical portion (12) in the form of two divisions or cylindrical half-housings (22), to receive keys from the inside and the outside of the door and a flat portion (13) extending parallel to the upper cylindrical portion with a notch (14) in the middle, through which a pawl is rotatably movable between said divisions, to operate the lock. Said cylindrical portion (12) contains the cylindrical core in which a series of ciphering pins extend in the conventional manner.

A standard lock is conventionally secured to a door assembly by a screw that is fixed at a hole (15) which is located in a bridge-like portion (16) under said notch (14) and which is perpendicular to the key axis of the cylinder lock. This region constitutes both vertically and horizontally the weakest line across the entire length of the lock assembly (11 ) and is potentially to be the first portion to be broken in case a burglar exerts a force e.g. via a lever rod to break the lock into pieces. It is well known in the art that the bodies of these locks are generally made of brass. Separation of the two

half-housings (22) will simply permit a thief to pull one of those out of the lock hole and reach the slot into which the pawl engages to unlock the door. To prevent this, the reinforcing structure according to the present invention takes advantage of an improved design and provides a two-pin reinforcement structure supported by two separate connection components having different material characteristics and connecting the two pin heads in the manner that one of the components resides on the inside of the other to form a multi-function connection.

The pins (18, 19), made out of steel, are vertically embedded in the bottom surface of the lock assembly (11). To avoid further weakening of the weakest line and to effect this region inadvertently as least as possible, the two pins (18, 19), which are at opposite sides of the screw hole (15) portion (16), are placed outside the space defined by the projection lines of the vertical borders of the notch within which the pawl is situated.

The pins (18, 19) are connected to each other by means of a non-extensible fixing device (20) in form of a substantially elliptical, closed and hollow body, fixedly attached to the pin (18, 19) heads and extending in the form of two arms around each pin head so as to cover the surface around the contour of the head portions. Contrary to the rest of the lock assembly (11), the fixing device is made out of steel, which is much stronger than brass. Each of the arms (21) of the elliptical fixing device (20) extends parallel to the longitudinal axis of the bottom surface of said flat portion (13). In case a burglar exerts e.g. laterally using a charging rod, a force sufficient to brake said bridge-like region (16) both in the upper and the lower part of said screw hole (15), then the security of the system will solely rely on the reinforcement elements.

A force sufficient to detach two cylindrical half-housings (22) may cause the two arms (21) of the fixing device (20) to be twisted. Despite probable deformation at the arms (21), depending on the force exerted, it will not be possible to uproot the pins (18, 19) since they are entirely embedded in the brass body with the exception of their head portions.

In other words, any deformation, even including a total rupture of the fixing device (20), will not cause the pins (18, 19) and the region around the pin heads, to get damaged and hence the two half-housing will still be attached to each other since a second connection element remains functional independent from the status of the

fixing device (20).

Said second connection element is an extensible spring element (23), made out of steel and laid in between the two pin heads and within the surface defined by the arms (21) of said non-extensible fixing device (20), in the form of a high tensile strength structure. In case a rupture takes place first in the bridge-like region (16) and second in said fixing device (20) in turn, said extensible element (23), which is fixedly attached to both pin heads still keeps two half-housings joined. To this end, said extensible element (23) absorbs the forces exerted and do not let the housings detach completely, substantially retarding separation of the two reinforcement members due to the elastic and energy dissipating structure of the connection.

The positions at which the two pins are located falls outside the space defined by the projection lines of the vertical borders of the notch (14) within which the pawl is situated. This design is helpful in that it avoids further weakening of the bridge-like portion (16) and keeps the pins (18, 19) outside the notch (14) line and thereby within the fully solid line to ensure a strong design. The uppermost portions of the pin (19, 19) heads, the fixing device (20) and the extensible spring element (23), which lies within the surface defined by the arms (21) of said non-extensible fixing device (20), lie all at the same plane. The steel pins (18, 19) are riveted to the lock body.