TECHNICAL FIELD

The invention relates to a cylinder lock, which can find application in the field of light industry, especially in the field of the locking devices with high security for residential houses, public and other buildings, cabinets, safes, and others where is required high burglary resistance. BACKGROUND ART

The typical double cylinder lock comprises a housing with inner and outer cylinder cores mounted therein, said housing is suitable to be mounted transversely through the lock box, as between both cylinder cores in the housing there is freely mounted rotating cam to drive the elements of the lock. The said cam represents a solid ring ;

with a tooth, as the ring rotates with the rotation of the inner or the outer cylinder core by means of a switch that transmits the rotary motion from the inner or the outer cylinder core to the ring, depending on the side of the cylinder lock where the right key is inserted, as a result of which the tooth rotates coming out radially from the cylinder lock and drives the lock's elements. It is known that in use such cylinder locks can be put under attack in an attempt to manipulate the lock mechanism. Such attacks may cause forced removal of the external cylinder core from the housing, thus providing an access to cam rotation. Alternatively, an attempt can be tried to break the housing in the central part connecting its two halves. This part of the housing is usually the thinnest and therefore the weakest, because it is suited to accommodate the rotation of the said cam. If this part of the housing can be broken, then the entire outer half of the cylinder lock can be removed, unless there were taken specific measures in the construction of the cylinder lock to resist this threat.

Cylinder lock is known from EP 0759492, where both cylinder cores are protected against withdrawal by special cam construction, consisting of two parts fixed each other and covering the inner edges of both cylinder cores, which makes pulling of both cylinder cores impossible when applying axial force. In the area of the ring both cam parts have engaging grooves which are longitudinally situated to the cylinder lock, as the groove in the first part is formed on the outer cylindrical surface of the ring, and in the second part - on the inner cylindrical surface. The groove in the cam's first part is inversely realized, so that the cam's second part passing over the first part couples therein forming closed ring, which by its protruded inwards periphery covers the inner edges of both cylinder cores through respective ring channels formed therein. At the same time in the tooth area the cam is cross divided into two parts, so that by their fixing each other by means of a spring pin passing through the longitudinal holes in the tooth, they form an entire cam. The inner cylindrical surface of the second engaging part of the cam in the tooth area is extended outwards in order to facilitate the assembly.

Said cylinder lock has a disadvantage - shaping of both composite parts of the cam requires additional milling, lathe and other operations, which increases the cost and complicate the assembly procedure.

SUMMARY OF THE INVENTION

The present invention seeks to provide a cylinder lock, resistant to the above mentioned attacks by providing an axial connection of both cylinder cores of the cylinder lock by means of a composite cam with simple and effective technological design that ensures easy installation and lower costs for the cam production.

There is thus provided cylinder lock with a composite cam consisting of two parts, which in assembled state represents a ring with a tooth as the said parts are fixed each other, at first in the ring area, so that form the closed ring which by its protruded inwards periphery covers the inner edges of the cylinder cores of the cylinder lock through respective ring channels and second - in the area of the tooth, where the said parts are connected each other by spring pin passing through the longitudinal holes formed therein, so that complimenting each other the parts form an entire cam rotated through a switch transmitting to the cam the rotary motion of respective cylinder core by the right key inserted therein.

In accordance with the invention the said parts of the cam are identical while assembling they are mirror symmetrical to the cam axis, whereby in the area of the ring both parts are interlocked around a transmitting plate by means of two identical locking teeth formed thereon, that engage in respective radial holes formed in the parts of the cam whereby after the parts interlocking both locking teeth are arranged symmetrically to the axis of the cam. Furthermore, in accordance with this invention the locking tooth has front radial surface for fixing upon the radial hole and back surface which passes smoothly towards the outer surface of the transmitting plate, in order to facilitate the installation. Moreover, according to the invention there is formed a profile hole in the transmitting plate to engage with the switch, through which there is transmitted rotary motion from the respective cylinder core to the cam. In accordance with the invention, on the inner cylindrical surface of the respective part of the cam there is engraved a channel covering the transmitting plate by interlocking of both parts of the cam. Furthermore, the radial hole and the said channel are realized in the respective part of the cam symmetrically to the central plane passing through the cam axis.

The advantage of the cylinder lock with a composite cam in accordance with the invention consists in that the said cam providing axial ly connection of both cylinder cores is an assembly of two identical parts which reduces its production cost.

Moreover, the both parts' interlocking proposed in the construction facilitates the assembly of the cam at first, and second - makes the construction technological effective, as the transmitting plate which realize the interlocking serves at the same time also for transmission of the rotary motion from the cylinder core to the cam.

DESCRIPTION OF THE FIGURES IN THE DRAWINGS

The present invention is explained in details using the following enclosed drawings: Fig. 1 represents a partial view of cylinder lock with a composite cam in the area of its coupling to both cylinder cores in the housing of the cylinder lock

Fig. 2 represents a frontal view of the assembled cam with partial section in the one cam parts' fixing area.

Fig. 3 represents a side view of the assembled cam.

Fig. 4 represents a frontal view of the cam disassembly.

Fig. 5 represents a side view of the cam's part 4. DETAILED DESCRIPTION OF THE EMBODIMENTS

In accordance with the invention, a preferred embodiment of cylinder lock with a composite cam is shown in Figs.1 , 2, 3, 4 and 5, whereat the composite cam 1 of the cylinder lock consists of two parts 4, as in assembled state the cam 1 represents a ring 2 with a tooth 3. The said parts 4 are fixed each other, at first in the ring area, so that form the closed ring 2, which by its protruded inwards periphery covers the inner edges of both cylinder cores 15 and 16 of the cylinder lock, through respective ring channels 18.

Second - in the area of the tooth 3 the said parts 4 are connected each other by spring pin 13 passing through longitudinal holes 14 formed therein, so that complimenting each other the parts 4 form an entire cam 1 rotated through a switch 17 transmitting to the cam 1 the rotary motion of the cylinder core 15 or 16 by the right key inserted therein. In accordance with the invention the said parts 4 of the cam 1 are identical while assembling they are mirror symmetrical to the axis 12 of the cam I which can be seen in the enclosed figures. In the area of the ring both parts 4 are interlocked around a transmitting plate 5 by means of two identical locking teeth 6 formed thereon, that engage in respective radial holes 10 formed in the parts 4, whereby after the parts 4 interlocking both locking teeth 6 are arranged symmetrically to the axis 12 of the cam 1. To simplify the assembly, the locking teeth 6 of the transmitting plate 5 have front radial shaped surface 7 for fixing upon the radial holes 10, and a back surface 8 shaped to pass smoothly to the outer surface of the transmitting plate 5. In the transmitting plate 5 there is formed also a profile hole 9 to engage with the switch 17 through which there is transmitted rotary motion from the respective cylinder core 1 or 16 to the cam 1 . On the inner cylindrical surface of the respective part 4 of the cam 1 there is engraved a channel 11 covering the transmitting plate 5 by interlocking of both parts 4. The said channel 1 1 and the radial hole 10 are realized in the respective part 4 of the cam 1 symmetrically to the central plane passing through the axis 12 of the cam 1.

The invention can be used for protection against burglary attacks both in double cylinder locks and half cylinder locks, as well as in knob cylinder locks, cylinder locks with special functions which implementations are equally included within the scope of the invention, with no size limitations and with any kind of the reversible mechanisms mounted in the cylinder lock for key decoding.