Removable core lock device

[0001] The present invention relates generally to lock arrangements and more specifically to a lock arrangement that comprises a key-activated construction with a removable core.

[0002] A cylinder lock comprises a central core and an outer casing or housing in which the core rotates. The housing is mounted in a suitable housing securing construction. A number of examples of prior art technology describe devices that are adapted to provide a removable or exchangeable cylinder lock core that provide the benefit of enabling such locks to be quickly re-keyed by relatively unskilled persons. Such re-keying may be required as a result of a possible deficiency in security or as the result of a lost key or the failure to return a key.

[0003] Patent publication U.S. Pat. No. 6,076,386 (Etchells et al) describes a lock which includes a removable core wherein a retaining element in the form of a ball is disposed in a concentrical groove formed on a core housing. One drawback with this solution resides in the deficiency of a code-related blocking mechanism for removal of the core.

[0004] A car lock that includes a removable core is described in U.S. Pat. No. 2,036,764, where the connection between the core and an adaptor that actuates the lock operating device has the form of a bayonet fitting which can be removed without requiring the use of a tool to this end. In order to use the lock, it is necessary to insert a long user key into engagement with a groove in the adaptor in order to be able to rotate not only the core but also the adaptor. Removal of the core from the adaptor is achieved with a short key with which the core is rotated in a specific direction through 90° relative to the adaptor.

[0005] Although this latter solution provides a simple construction, it has several drawbacks. Firstly, it relies on the strength mechanics of the key tip for rotation of the adaptor, which results in an unreliable operation. Secondly, this lock can be manipulated relatively easily.

[0006] An object of the present invention is to provide a lock which includes a removable core and with which the drawbacks of known lock devices are eliminated or at least reduced.

[0007] The invention is based on the understanding that it is possible to design a cam adapter such that a part of the adapter will grip around one or more code pin tumblers disposed in the cylinder core, wherein the position of the code pin tumblers determines whether or not the cylinder core can be moved axially relative to the cylinder housing.

[0008] According to the present invention there is provided a key and lock device that includes a removable core as defined in claim 1, and a service key as defined in claim 8.

[0009] The inventive device eliminates or at least reduces the drawbacks associated with known technology as mentioned above. The lock device according to the present invention as defined in the accompanying claims has a simple design which, nevertheless, provides a high degree of security with regard to enabling the replacement of the cylinder core.

[0010] Further preferred features of the invention will be evident from the dependent claims.

[0018] There will now be described in more detail a preferred embodiment of the present invention. FIG. 1 is an exploded view of the components of a lock device constructed in accordance with the invention. A cylinder housing 10 includes a generally circular aperture or opening 10a which is intended to accommodate a generally circular cylindrical core 20. The core includes a key slot 20a which receives a key 30 in a typical fashion. Two side bars (lacking in FIG. 1) are provided in a respective longitudinally extending groove 20b in the core, of which one can be seen in FIG. 1. Pressure pins and springs (not shown) are provided for biasing the side bars radially outwards and into engagement with a respective longitudinally extending groove 10b in the inner surface of the opening 10a, in which one groove can be seen from FIG. 1. A side bar arrangement of the aforesaid type is described for instance in the International Patent Publication WO93/12314 (Häggström), which is included herein by reference.

[0019] A cam adapter 40 is rotatably disposed in the inner part of the opening 10a in the cylinder housing. The cam adapter includes a circular body 40a from which there extends a tail piece 40b. The tail piece is adapted to be operatively coupled to a stop washer 41, a cam 42, a locking washer 43 and a nut 44. The cam 42 is held in place on the driver by means of the nut 44. The cam adapter is thus rotatably mounted in the inner part of the opening 10a in the cylinder housing 10 and its removal is prevented by the nut 44.

[0020] Turning to FIGS. 2a-c, it will be seen that the cam adapter also includes two claw-like legs adapted for engagement with a respective code pin tumbler 22 disposed in the inner end portion of the cylinder core 20. The function of these legs will be explained below.

[0021] The code pin tumblers 22 have a lower circular body portion 22a which terminates in a circular lip 22b of larger diameter at its bottom end. The code pins also include an upper circular body portion 22c which has a narrower waist portion or circumferential groove 22d. When inserting a key into the key slot 20a, the pins are forcibly guided in a vertical direction by virtue of the lip portion 22b engaging in the code groove 30a in the side surfaces of the key bit. This feature is known to the art, for instance from the patent publication WO93/12314 mentioned above.

[0022] The upper body part 22c of the code pins has a diameter which harmonizes with concave recesses in the legs 40c of the cam adapter. It will also be seen from FIG. 2c that the part of the legs 40c that engage around the code pin 22 have a height which is slightly less than the height of the waist portions 22d of the code pins. This means than when the waist portions of the code pins are precisely level with the legs of the cam adapter, see FIGS. 3a-c, the code pin is able to move past the outer end portions of the legs as the cylinder core is moved in towards or out from the opening 10a of the cylinder housing. On the other hand, if the waist portions of the code pins are at a height other than that at which they register with the legs of the cam adapter, see FIGS. 2a-c, the upper body portion 22c of the code pins will block axial relative movement between the cam adapter and the code pins. Because the cam adapter is mounted in the cylinder housing 10 and the code pins are disposed in the cylinder core 20, removal of the cylinder core from the cylinder housing will be prevented.

[0023] The waist portion 22d can be placed at different heights in the upper body portion 22c of the code pins. This results in different codes. In one preferred embodiment of the invention, the waist can be placed at three mutually different heights, wherewith two code pins will provide nine different combinations.

[0024] The construction can be reinforced by providing one or more balls 20c in recesses disposed in the barrel or mantel surface of the cylinder core so as to extend slightly beyond said barrel surface. These balls are intended to extend in a circumferential groove 10c in the opening 10a and function as means for taking-up axially acting forces in all positions of rotation with the exception of when the balls are co-incidental with recesses 10d, therewith enabling the cylinder core to be inserted to a core insertion position, see FIG. 5c.

[0025] Mounting of the cylinder core 20 will now be described with reference to FIGS. 5a-e. FIG. 5a shows the cylinder core at the beginning of its insertion into the opening 10a of the cylinder housing 10, wherewith a service key 30′ is inserted in the key slot 20a. FIG. 5b illustrates commencement of the engagement of the legs 40c of the cam adapter 40 with the longitudinally extending grooves 20b in the barrel surface of the cylinder core, wherewith the cam adapter rotates with the cylinder core. However, the balls 20c prevent further insertion of the cylinder core. When the cylinder core has been rotated through 45°, see FIG. 5c, the balls 20b will coincide with the recesses 10d in the opening of the cylinder housing. This allows the cylinder core to be moved to a fully inserted position, see FIG. 5d. Finally, the cylinder core is rotated to its original position, see FIG. 5e, and the service key can be removed from the lock. In this state of the lock, the balls 20c block axial movement between the cylinder housing 10 and the cylinder core 20. When mounting of the cylinder core is complete, the lock device can be manoeuvred with a user key.

[0026] The cylinder core is dismantled from the lock by carrying out the above steps in a reverse order.

[0027] Because the cylinder core and the cam adapter are held in a locked axial position in the cylinder housing through the agency of the balls and corresponding grooves in the cylinder housing opening when said core and adapter are in a locked state, it is a simple matter for an on-site fitter to choose whether the lock device shall be adapted for a right-hand or left-hand turn. The turning direction can be changed by taking off the stop-washer 41 and turning it through 180°, whereafter it is mounted once again on the tail piece 40b of the cam adapter, see FIGS. 6a-d.

[0028] The described lock device affords several benefits. Firstly, there is obtained a simple but nevertheless reliable solution. Several codes for the function of the service key can be obtained while simultaneously the number of components required are kept at a minimum.

[0029] Although the inventive lock device has been described with reference to a preferred embodiment, the person of average skill in this art will be aware that variations can be made within the scope of the accompanying claims. Furthermore, although there has been described a lock which includes two longitudinally extending recesses in the cylinder core it will be understood that the inventive concept can also be applied with a different number of recesses. A lock device that includes side bars has been described. Instead of a lock with conventional pins, as described, the lock may comprise upper pins and bottom pins according to the invention.

[0030] Balls have been described as means for fixating the cylinder core axially. It will be understood that other solutions can be applied for axial fixation of the cylinder core, or that the fixation achieved through the medium of the cam adapter and pin is the only fixation required.