Technical Field of the Invention

The present invention relates to a high security cylinder lock having an alarm circuitry for indicating attempts of lock snapping. The proposed cylinder lock is able to generate at least an audible alarm signal in result of a lock snapping attempt and also is able to withstand the lock snapping attempt.

Background of the Invention

Lock snapping is a frequently used technique for breaking in a locked place. Typically a burglar obtains a device for snapping the outer end of a double cylinder lock and then applies a torque, usually in the vertical direction if not in combination to both vertical and horizontal directions. The weakest point in a double cylinder lock is the hole usually in the middle of the two cylinder halves, said hole drilled right below the plug for securing the cylinder lock to the door. Once the burglar applies torque to the snap device, the cylinder lock breaks apart and the two broken cylinder halves separate from each other. The cylinder half on the outer side of the door remains on the snap device whereas the cylinder part on the inner side is pushed by the burglar to fall towards the inside of the door. The burglar then inserts a new cylinder lock into the hole and easily opens the lock with his own key. An alternative is to force the deadbolts be received in the body of the lock through use of an L-shaped tool.

EP 2 208 839 relates to a high security lock cylinder with a pre-determined breaking line intended for breaking during a lock snapping attempt. Said line is mechanically weakened to be ruptured in response to a breaking force applied by a snapping tool. When the cylinder lock is broken as a result of an attack, the bridge between the two cylinder halves remains intact and malicious removal of the lock cylinder is prevented. The remaining part of the attacked cylinder is still able to receive the key thus allowing the original key holder still able to lock and unlock the cylinder lock.

DE 10 325 731 relates to an alarm trigger for lock cylinders against unauthorized break-in attempts. The cylinder lock has non-conductive means between two electrically conductive means in a casing which only produces trigger contact when broken or deformed. When the lock cylinder is broken at the bridging part in between the two cylinder halves or it is removed from its dedicated location, the conductive means of the assembly instantly get in contact and thus an alarm signal is triggered. Said assembly does still not prevent the unauthorized person from entering the building, nor does it allow the subsequent use of the original key of the authorized person in order to unlock and lock the door even after the lock snapping attack. Hence, it is a must that the cylinder lock shall be replaced by a new cylinder lock after each and every lock snapping attack. A further disadvantage is the fact that the unauthorized person may enter the building after lock snapping attack and then destroy, deactivate or de-energize the alarm arrangement. Additionally, this device requires an uninterrupted power supply and montage of conductive cables and specifically trained montage personnel. More important than all, the functionality of this assembly seriously relies on a metal part which is subject to metal fatigue in time.

DE 3 913 204 relates to a cylinder lock core protection device which has an outer drilling protection shield for detection of an unauthorized attempt. The unauthorized person may still enter the building after a lock snapping attack, and may then deactivate or destroy the alarm arrangement.

DE 83 08 613 relates to a lock with electrical tapping-alarm signaling device, its housing and a bolt member. The assembly comprises a cover for the alarm triggering mechanism, which is naturally bigger than the lock cylinder itself. Thus said assembly requires an off-size montage space in the door body.

WO 2009/093 090 relates to a signaling device for burglary prevention system with electrical body lock sensors placed on the cylinder lock insert joining an alarm system through wires. This assembly requires an uninterrupted power supply and montage of conductive cables and is not suitable for use in existing doors.

DE 4 104 042 relates to a core protector for a cylinder lock, incorporating a blade directed towards cylinder core for cutting a conducting foil in order to trigger an alarm mechanism. Attempted entry drilling forces push the rosette backwards along bars and the blade cuts the foil, thereby triggering an alarm.

Objects of the Invention

An object of the present invention is to provide a cylinder lock which comprises an alarm circuitry located inside the cylinder body for facilitating installation to existing doors. Another object of the present invention is to provide an alarm incorporated cylinder lock which triggers during a lock snapping attempt.

Another object of the present invention is to provide an alarm incorporated cylinder- lock which is operational even after a successful lock snapping attempt.

Summary of the Invention

A cylinder lock having a first cylinder half, which in use, is mounted on the indoor side and a second cylinder half, which in use, is mounted on the outdoor side of a door, is disclosed. The cylinder lock further comprises a notch cut out on the outdoor end of the second cylinder half for forming a breakable tip portion on said second cylinder half. A rod extends along the second cylinder half and enters, partly at its first end, in the first cylinder half. The rod is secured, at its second end, to the tip portion of the second cylinder half. The cylinder lock further comprises a volume formed on said first cylinder half for accommodating an alarm circuitry including at least an electronic circuit board, a magnetic switch and a magnet. The first end of the rod is interposed between the magnetic switch and the magnet of the alarm circuitry such that when the tip portion of the second cylinder half breaks apart, the rod slides out of the first cylinder half for detection of a break-in attempt.

The cylinder lock according to the invention may further comprise, within the second cylinder half, a spring loaded block pin for blocking the gap of said rod once the rod slides out of said second cylinder half such that re-insertion of said rod is eliminated. If the gap of the rod remains vacant, it may be possible that the alarm may be de- activated by inserting a thin metal object, or back inserting the rod itself, into the gap and filling the volume in between the magnet and the magnetic switch.

Brief Description of the Figures

Accompanying drawings are given solely for the purpose of exemplifying a cylinder- lock whose advantages over prior art will be explained in detail hereinafter:

Fig. 1 demonstrates a side view (a) and cross-section A-A (b) of an embodiment of the cylinder lock according to the present invention.

Fig. 2 demonstrates a rear perspective view (a) and front view (b) of the first embodiment of the cylinder lock according to the present invention. Fig. 3 demonstrates a bottom view (a), a side view (b) and cross-section A-A (c) of the first embodiment of the cylinder lock according to the present invention.

Fig. 4 demonstrates a rear perspective view (a) and front view (b) of a second embodiment of the cylinder lock according to the present invention.

Fig. 5 demonstrates a bottom view (a), a side view (b) and cross-section A-A (c) of the second embodiment of the cylinder lock according to the present invention.

Fig. 6 demonstrates a rear perspective view of a variation of the second embodiment of the cylinder lock according to the present invention.

Fig. 7 demonstrates a bottom view (a), a side view (b) and cross-section A-A (c) of the variation of the second embodiment of the cylinder lock according to the present invention.

Fig. 8 demonstrates a rear perspective view (a) and a front view (b) of a third embodiment of the cylinder lock according to the present invention.

Fig. 9 demonstrates a bottom view (a), a side view (b) and cross-section A-A (c) of the third embodiment of the cylinder lock according to the present invention.

Fig. 10a and 10b demonstrates respectively, the bottom and side views of a cylinder lock according to the present invention.

Fig. 10 c demonstrates the A-A cross section view of the cylinder lock of Fig. 10a. Detailed Description of the Invention The present invention overcomes the above-mentioned shortcomings of the prior art by way of incorporating an alarm circuitry inside the body of a cylinder lock where said cylinder lock has a pre-determined breaking line for installation on the outer part of a door. The present invention therefore provides an alarm triggering cylinder lock which remains operational even after a successful lock snapping attack. The core idea underlying the present invention is to provide a cylinder lock;

- which will withstand a lock snapping attack,

- which will scare the unauthorized person during and after said attack and thereby force him to cease the attack, and

- which will remain intact and operational even if the attack turns out to be successful and part of the cylinder is broken apart.

The cylinder lock according to the present invention therefore eliminates the need for an additional locksmith work after a lock snapping attack. A new cylinder lock may be installed easily by way of unscrewing the securing bolt, replacing a new cylinder lock and then screwing the securing bolt back in place.

The present invention additionally provides an alarm signaling device which can be installed inside the body of a cylinder lock, thus preventing necessities of extra space to be opened or drilled in the door body and of additional alarm indication means, such as an audio source, a buzzer etc.. The present invention may further provide a cylinder lock which is suitable for communicating with other alarm systems which may suitably be found in place. Even though the well-known motion detectors or magnetic contact sensors of existing alarm systems may not alert during a lock snapping attack, the cylinder lock of the present invention allows, in real time, dissemination of attack information with the surrounding alarm systems.

The following reference numerals have used in the appended drawings;

(1) cylinder lock body

(2) rod

(3) magnetic switch

(4) battery

(5) electronic circuit board

(6) buzzer

(7) anchor pin

(8) tip portion

(9) cover

(10) notch

(11) sonic outlet channel

(12) echo surface

(13) magnet

(14) connector

(15) cable

(16) external connection apparatus

(17) external buzzer box

(18) bridge

(21) first cylinder half

(22) second cylinder half

(23) block pin

In a first embodiment shown in Figures 1, 2 and 3; the cylinder lock body (1) comprises an alarm circuitry located in the first cylinder half half. The cylinder lock body (1) comprises two plugs connected by a cam. The cylinder lock body (1) has a first cylinder half (21) for mounting on the indoor part of a door and a second cylinder half (22) for mounting on the outdoor part of a door. In all drawings attached to this specification, the first cylinder half intended for indoor part has alarm circuitry and no tumbler pins whereas the second cylinder half intended for outdoor side has a plurality of tumbler pins. The cylinder (1) in the appended drawings is a Euro profile whereas the invention may be applied to other types of cylinders as well.

The second cylinder half (22) according to the present invention has a notch (10) in the form of a partial cut out which is intended to break during a snapping attempt. The purpose for cutting a notch (10) is to prevent breaking of the bridge (18) and to prevent breaking apart of the first and second cylinder halves. Once the cylinder is snapped from the second part, the snapping tool would snap the tip portion (8) of the second cylinder half (22) and break it apart without jeopardizing the bridging portion in between the first and second cylinder halves.

A rod (2) made of a metallic material is fixed by an anchor pin (7) in the tip portion (8) of the second cylinder half (22) in order to obtain a firm attachment between the rod (2) and tip portion (8). The metallic rod (2) extends along the body of the second cylinder half (22) and enters partly in the first cylinder half (21) where the alarm circuitry is located. It is important however that the metallic rod is secured to the tip portion (8) of the second cylinder half (22) since it has to slide out of the cylinder body if or when the tip portion breaks apart in result of a snapping attempt. Part of the rod (2) which extends inside the first cylinder half (21) remains in between a magnetic switch (3) and a magnet (13) located in said first part. Under normal operating conditions, part of said rod (2) is always interposed between the magnet (13) and the magnetic switch (3) such that the magnetic switch (3) cannot sense the magnet (13) located opposite said magnetic switch (3). The existence of the rod (2) between the magnet (13) and the magnetic switch (3) ensures that the alarm is not triggered.

The first cylinder half (21) has a volume for containing various components of the alarm circuitry. These include at least an electronic circuit board (5), a buzzer (6), a battery (4), a magnetic switch (3) and a magnet (13). This volume is depicted like a rectangular prism in the appended drawings. Conveniently, the volume is closed by a cover (9) in order to protect the electronic circuitry contained therein.

The magnetic switch (3) may be a reed switch located suitably for sensing the motion of the metallic rod (2) during a lock snapping attack. As the metallic rod (2) is secured to the tip portion (8) of the second cylinder half (22), the rod slides initially out of the first cylinder half (21) when the tip portion (8) breaks apart. As the position of the rod (2) between the switch (3) and magnet (13) changes and eventually the rod completely slides out of the interspace, this is sensed by the switch and an alarm is triggered. An audible signal is then released by a buzzer (6).

In order to increase the intensity of the sound generated by the buzzer (6), an echo surface (12) is formed on the cover (9). The echo surface is concave arc form such that the sound generated by the buzzer (6) is directed towards to the second cylinder half (22) whose tip portion (8) is detached. Additionally, a sonic outlet channel (11) is formed on the second cylinder half (22) for conveying the sound waves from the buzzer to the outlet of the second cylinder half. The person making the lock snapping attack hears the sound more intensely since the sound waves are localized in the sonic outlet channel (11).

A second embodiment shown in Figures 4 and 5 varies from the first embodiment by the fact that the first cylinder half (21) is equipped with a connector (14) for transmitting data from the electronic circuit board (5) to the periphery, such as an alarm system found in the building or the flat. In this case, the cylinder need not to have a buzzer (6) and/or a battery (4), as these two components may conveniently be placed outside the cylinder, e.g. on the inner surface of the door. The connector (14) may be used to transmit not only data but also energy.

A third embodiment further comprises an external connection apparatus (16) for mounting to the inner face of the door. As is shown in Figs. 6 and 7 the external connection apparatus (16) connects through a cable (15) to the connector (14). Data from the electronic circuit board (5) can be transferred to the external elements via cables or wireless means; so that the alarm incorporated cylinder lock can be used in communication with various other peripheral devices such as loudspeakers, fire alarms and closed circuit camera systems etc. Once the alarm is triggered, this data may be conveyed to external peripherals e.g. for the purpose of notifying the police or the house keeper of the lock snapping attempt. This data may be conveyed in many ways through use of wired or wireless communication devices. The connector (14) may additionally be used for establishing connection with an external buzzer who may generate a much higher level of audible noise for alerting the neighborhood. The energy consumed by the external connection apparatus (16) may be supplied either by an external battery or by the mains line. The alarm incorporated cylinder lock may be equipped with an external buzzer box (17) as shown in Figures 8 and 9. The buzzer box (17) may also contain additional battery for energizing a second buzzer or, precautionary, also the electronic circuit board (5) contained in the first cylinder half. The cylinder lock according to the invention may further comprise, within the second cylinder half (22), a spring loaded block pin (23) for blocking the gap of said rod (2) once the rod (2) slides out of said second cylinder half (22) such that re-insertion of said rod is eliminated. If the gap of the rod remains vacant, it may be possible that the alarm may be de-activated by inserting a thin metal object, or back inserting the same rod (2) itself, into the gap and by filling the gap in between the magnet (13) and the magnetic switch (3). If an object is inserted in between the magnet (13) and the magnetic switch (3), the alarm circuitry may cease to indicate the break-in attempt as the alarm circuitry may be deceived by the inserted object pretending as part of the rod interposed in between the magnet (13) and the magnetic switch (3). Therefore, a spring loaded block pin (23) may conveniently be used for blocking the gap of the rod (2) within the second cylinder half (22) and thereby preventing insertion of an object in between the magnet (13) and the magnetic switch (3). The block pin (23) may be employed in any of the embodiments outlined so far in this text.