LOCKING DEVICE FOR A BICYCLE

Abstract: The invention provides a locking device for a bicycle for mounting in a frame tube (20), comprising a cylindrical lock housing (2) which accommodates a locking block (4) and key-operated means (3, 4a, 5, 7) for moving at least one locking pawl (1, 13) in the housing (2) between a retracted position and an extended position, in which the locking pawl (1, 13) protrudes from at least one of the ends in the cylindrical housing (2) and engages an opening or recess in one or more of the parts (21, 22) rotatably mounted on a bicycle frame, said cylindrical lock housing (2) having an outside diameter essentially corresponding to the inside diameter of a frame tube, preferably the lower tuber (20), so that the entire locking device may be mounted concealed inside the tube (20) on the bicycle frame in a position so that just the keyhole is accessible from the outside through a recess in the frame tube. Such a locking device provides an extremely effective lock to prevent theft of a bicycle, as all the locking parts are placed inside the frame tube, and it is therefore practically impossible to force the lock without simultaneously destroying the bicycle.

Description: A locking device for a bicycle The present invention relates to a locking device for a bicycle and comprising an elongated cylindrical lock housing which comprises a locking block with a keyhole and means for moving at least one locking pawl in the housing between a retracted position and an extended position, in which the locking pawl protrudes from at least one of the ends in the cylindrical housing and engages an opening or recess in one or more of the parts rotatably mounted on a bicycle frame. The invention also relates to a frame for a bicycle in which a locking device is incorporated. For the purpose of locking bicycles as a safeguard against theft, locking devices arranged in the frame are known today, which is an attractive solution since such a type of locking device takes up very little space. EP-A-0 156 416 discloses a locking device of this type, in which the lock housing is formed as a termination on the lower tube so that the lock housing is an integrated part of the tube, said lock housing having the same di- ameter as the tube. At one end the lock housing is fixedly mounted on the end of the lower tube, and at the other end it is fixed to the adjoining frame tube, i.e. the crank or the head tube. The locking pawls extend inside the tube and can lock the pedals and the front fork of the bicycle. This locking device requires a special structure of the bicycle frame and has the drawback that the rigidity and the strength of the bicycle frame are weakened in order to accommodate the locking device. The patent specifications DE-A-35 41 169 and US-A-2 055 149 disclose a corresponding type of locking devices. This type, like the above-mentioned locking device, is adapted to lock the front fork as well as the pedals, but in contrast to the above-mentioned device the lock housing is here introduced into the lower tube of the frame, and may then be secured from the outside to the frame in connection with the actual locking part into which the key is inserted for operation. Hereby a protruding lock- ing part will occur on the frame, said locking part being either provided in the frame or in the form of a bushing which is screwed into the lock housing from the outside. This protruding operating part of the lock, however, is very exposed and is therefore very likely to be damaged. Furthermore, this locking device is difficult to mount, just as it is relatively easily accessible because of the external mounting parts, so that potential cyclists who want to use a thus locked bicycle in an unauthorized manner but do not have an authorized key to deactivate the bicycle lock, can easily force the lock. Moreover, the British Patent Specification No. 814 034 discloses a locking device which uses a number combination lock consisting of a plurality of rings which are mounted on one of the tubes of the frame. This structure is partly complicated to mount and partly vulnerable to intentional or unintentional external impacts. Further, WO93/01964 discloses a locking system in which the crank, the handlebars and the braking function of the rear wheel can be locked. This structure is extremely difficult to mount in a bicycle frame, as the locking system comprises many individual parts, which moreover have to be adjusted with respect to each other in connec- tion with the mounting in order to avoid malfunction of the lock. It is thus a costly locking system where the reliability of the locking function depends on the precision of the fine adjustment. Accordingly, the object of the invention is to provide a locking device for a bicycle frame to prevent theft of a bicycle, which obviates the drawbacks of the above-mentioned known locking devices of this type. The invention comprises a locking device of the type men- tioned in the opening paragraph in which the cylindrical lock housing has an outside diameter essentially corresponding to the inside diameter of a frame tube, preferably the lower tube, so that the entire locking device may be mounted concealed inside the tube on the bicycle frame in a position so that just the keyhole is accessible from the outside through a recess in the frame tube, and that the means for moving the locking pawls comprise a locking plug which is transverse to the lock housing and is rotatable in the locking block by key operation to activate the lock, and that the locking plug is firmly connected with a preferably centrally positioned gear wheel which is in engagement with the rack provided in the inner end of a locking pawl. A locking device according to the invention provides an extremely effective lock to prevent theft of a bicycle, as all the locking parts are positioned within the frame tube, and therefore it is practically impossible to force the lock without simultaneously destroying the bicycle. The locking device according to the invention moreover has the advantage that the strength of the frame structure is not weakened because of the mounting of this locking device, just as the locking device according to the invention does not require unnecessarily many adjust- ments to adapt the locking device to the frame and ensure the locking function. Furthermore, a slender lock housing is obtained with this locking device, suitable for mounting inside a frame tube. Further, the locking pawls may hereby be arranged centrally in the tube in which the locking device is mounted. In the preferred embodiment of the locking device according to the invention the lock housing accommodates two locking pawls which are simultaneously extensible at their respective ends of the housing to lock both the handlebars and the crank on a bicycle. It is moreover preferred in a locking device according to the invention that at least one of the locking pawls, preferably the one for locking the crank, is provided with a spring element for spring activation of it. This facilitates the actual activation of the lock, as the lock may be activated, whereby the spring element of the locking pawl is compressed, following which the rotating parts to be locked, such as e.g. the crank, rotate until it is in a lockable position in which the spring element can expand so that the spring-loaded locking pawl jumps out of the recess in e.g. the crank and locks it. A similar device may of course be arranged in connection with the locking of the front fork in the frame. In a further development of the locking device according to the invention, one end of the lock housing is provided with a wire lock bushing having a T-shaped groove with a reception opening for insertion and locking of the end of a wire introduced through a hole provided in the frame. The locking device may hereby be extended to lock the bicycle to a wire, which may in turn be secured to a bicycle stand or the like. In a preferred embodiment of the invention, the locking housing comprises two synchronously slidable wire lock housings for receiving the first end and the second end, respectively, of a locking wire. This provides a particularly advantageous solution, as both ends of the locking wire may be locked to the frame tube, both when the wire is used in connection with locking and when it is not in use. A particular embodiment of the locking wire in that connection is a spiral-shaped structure. A further aspect of the invention provides a frame for a bicycle for mounting of a locking device according to the first aspect of the invention, wherein the tube of the bicycle, preferably the lower tube, which is to accommodate the locking device, is formed with a keyhole through which a key may be inserted for operating the lock. If the bicycle frame is moreover to be used for the wire locking, the frame may moreover be provided with one or more separate holes for receiving the wire end in the frame. The invention will be described more fully below with reference to the accompanying drawing, in which fig. 1 shows a section of a bicycle frame with a lock- ing device according to a first embodiment of the invention, fig. 2 shows a longitudinal section through the locking device, fig. 2a shows a variant of a part of fig. 2 for wire locking, fig. 3 shows a lateral view of the lock housing, fig. 4 shows an end view of the same, fig. 5 shows a top view of the same, fig. 6 shows a view of the gear wheel in the lock housing, fig. 7 shows a section of a bicycle frame with a locking device according to a second embodiment of the invention, and fig. 8 shows a sectional view of a frame tube Fig. 1 shows a section of a bicycle frame where a locking device according to the invention is mounted in the lower tube 20 in such a manner that a locking pawl 1 protrudes from the lower tube 20 and into the head tube and locks the front fork 21, the other locking pawl 13 being in locking engagement with the crank 22. The extension of the two locking rods 1, 23 for locking the front fork 21 and the crank 22, respectively, takes place through activation of the lock housing whose locking mechanism L is shown more fully in fig. 2. As will appear from fig. 1, the front fork 21 and the crank 22 are formed with recesses for receiving the locking pawls 1, 13. The lock housing 2, as shown in fig. 2, is composed of a locking mechanism L mounted therein. The lock housing 2 is divided into two halves (not shown) in the preferred embodiment. The front locking pawl 1 may be extended out of the lock housing 2 by activation of the mechanism L with simultaneous extension of the rear locking pawl 13 for locking the front fork 21 and the crank 22, respectively. The locking mechanism L comprises a locking block 4 in which a locking drum 4a is arranged. In connection with the locking drum 4a, a key may be inserted for activating the lock by rotation, thereby causing a gear wheel 5 connected with the locking drum 4a (see figs. 3-5) to rotate. This gear wheel 5 is in connection with two racks 3, 7 which are positioned on their respective sides of the locking block 4, and which are firmly connected with the locking pawls 1, 13. Rotation of the gear wheel 5 thus causes the locking pawls 1, 13 to slide forwards or rearwards in the locking device. The locking pawls 1, 13, which are preferably made of steel, are guided in the lock housing 2, which is preferably of a synthetic mate ¬ rial, such as nylon or a similar suitable material. The rear locking pawl 13 is connected with a locking rod 11 which, in connection with the attachment to its associated rack 7, is slidably secured with respect to the rack 7. At the end, the locking rod 11 is provided with a locking ring 6 ensuring that the locking rod 11 is not displaced out through the opening in the rack 7 through which it extends. The locking rod 11 is moreover provided with a compression spring 8 which engages the rack 7 at one end and engages another locking ring 9 at the other end. The locking mechanism L may hereby be activated also if the recess in the crank 22 is not positioned in align- ment with the locking pawl 13, as in this case the locking pawl 13 is compressed around the compression spring 8. The crank 22 may then be rotated until its recess is properly positioned and the locking pawl 13 is moved out into the recess by means of the compression spring 8 and locks the crank 22. In the preferred embodiment of the locking device according to the invention, this is constructed such that the locking mechanism may be arranged in the upper part of the lower tube 20 so that the lock is easier to operate. To support the locking rod 11, which is of a considerable length in this embodiment, the lock housing is extended with an adapter tube 10 in a direction toward the crank end. The adapter tube 10 is preferably of a plastics material or other synthetic material, such as nylon. The end of the adapter tube 10 is provided with a bushing 14 to guide the locking pawl 13, which is secured to the end of the locking rod 11 protruding from the adapter tube 10. In the preferred embodiment the locking pawl 13 is screwed onto threads on the end of the locking rod 11, which is moreover provided with a lock nut 12. The bushing 14 is preferably of nylon or a similar synthetic material . Fig. 2a shows a variant of the embodiment of the crank end of the locking device according to the invention where a wire lock housing 16 is inserted in connection with the attachment of the locking pawl 13 to the locking rod 11. The bushing 14 is here formed with an opening so that the end of a wire 15 may be inserted through this opening and into the wire lock housing 16. The end of the wire is formed with a T-shape or a ring-shaped recess in the end member which corresponds to the groove of the wire lock housing. The wire lock housing 16 and the opening in the bushing 14 are so positioned that the wire 15 may be inserted when the locking device is deactivated, following which the wire lock housing 16 is displaced outwards together with the locking pawl 13 by activation of the lock, thereby locking the wire. The groove in the wire lock housing 16 is shaped so that the wire 15 cannot be removed as long as the locking device is activated. Figs. 3 to 6 show the locking block 4 with the gear wheel 5, seen from different sides. The locking drum 4a is arranged in the locking block 4 so that it can rotate by operation with a key 17. The gear wheel 5 is firmly mounted centrally on the locking drum 4a so that it ro- tates with the drum 4a when this rotates. The gear wheel 5 is provided in two halves which, when assembled, are kept in position in the locking block 4. The gear wheel 5, when assembled has a recess 5a in the centre which corresponds to a similar configuration on the locking drum 4a (shown in broken line in fig. 5) . The locking device of the invention described above may be incorporated in a bicycle frame in that the frame is formed with a hole for mounting in the tube of the crank 22 in alignment with the lower tube 20. The rod-shaped locking device of the invention may be inserted through this hole and into the lower tube 20. The lower tube 20 of the frame is formed with a hole in alignment with which the keyhole in the locking drum 4a may be arranged, and through which the key may be inserted for operation of the lock. If the locking device is moreover provided with a wire lock housing, the frame may moreover be provided with one or more holes which correspond to the po- sition of the wire lock housing. Figure 7 shows a second embodiment in which the locking device is provided with two wire lock housings 16. As shown in fig. 7, the wire lock housing may be placed in the lower tube 20 or in the saddle tube 23 of the bicycle frame. The position in the saddle tube 23 is particularly suitable for subsequent mounting. The bicycle frame is provided with two mounting holes 24, 25 whose positions correspond to the positions of the wire lock housings 16. The two mounting holes 24, 25 are so positioned with respect to each other that a spiral- shaped locking wire 15 may easily be locked to the frame. The two mounting holes 24, 25 are both axially and radi- ally offset with respect to each other, as shown in fig. 7 and fig. 8, respectively. When the locking wire 15 according to this embodiment is not in use, it is thus also mounted in the frame tube 20, 23, but owing to its spiral shape it will naturally as- sume an unobstructing position along the frame tube. A spiral-shaped locking wire 15 and the associated position of the mounting holes 24, 25 on the frame are thus particularly advantageous, since with this shape it can easily be arranged on the bicycle in such a manner^ that it does not interfere with the normal use of the bicycle. List of references : 1 Locking pawl at front fork 2 lock housing 3 rack 4 locking block 4a locking drum 5 gear wheel 5a recess in gear wheel 6 locking ring 7 rack 8 compression spring 9 locking ring 10 adapter tube 11 locking rod 12 lock nut 13 locking pawl at the crank 14 bushing 15 wire 16 wire lock housing 17 key 20 lower tube 21 front fork 22 crank 23 saddle tube 24 mounting hole 25 mounting hole locking mechanism

Claims: PATENT CLAIMS: 1. A locking device for a bicycle for mounting in a frame tube (20), comprising a cylindrical lock housing (2) which accommodates a locking block (4) and key-operated means (3, 4a, 5, 7) for moving at least one locking pawl (1, 13) in the housing (2) between a retracted position and an extended position, in which the locking pawl (1, 13) protrudes from at least one of the ends in the cylindrical housing (2) and engages an opening or recess in one or more of the parts (21, 22) rotatably mounted on a bicycle frame, c h a r a c t e r i z e d in that the cylindrical lock housing (2) at least sectionally has an outside diameter essentially corresponding to the inside diameter of a frame tube, preferably the lower tube (20), so that the entire locking device may be mounted concealed inside the tube (20) on the bicycle frame in a position so that just the keyhole is accessible from the outside through a recess in the frame tube, and that the means for moving the locking pawls (1, 13) comprise a locking plug (4a) which is transverse to the lock housing (2) and is rotatable, by key activation, in the locking block (4) for activating the lock, and that the locking cylinder (4a) is firmly connected with a preferably cen- trally positioned gear wheel (5) which is in engagement with the rack (3, 7) provided in the inner end of a locking pawl (1, 13) . 2. A locking device according to claim 1, c h a r a c - t e r i z e d in that the lock housing (2) accommodates two locking pawls (1, 13) which are simultaneously extensible at their respective ends of the housing (2) for locking the handlebars (21) and the crank (22) of a bicycle. 3. A locking device according to claim 1 or 2, c h a r a c t e r i z e d in that at least one of the locking pawls (1, 13), preferably the one for locking the crank, is connected via a spring element (8) for locking by spring activation. 4. A locking device according to any one of the preceding claims, c h a r a c t e r i z e d in that one end of the lock housing (2) is provided with a wire lock housing (16) slidable by operation of the lock and having a T- shaped groove with a reception opening for insertion and locking of the end of a wire (15) inserted through a hole provided in the frame. 5. A locking device according to claim 4, c h a r a c - t e r i z e d in that the lock housing (2) comprises two synchronously slidable wire lock housings (16) for receiving the first end and the second end, respectively, of a locking wire (15) . 6. A frame for a bicycle for mounting of a locking device according to any one of the preceding claims, c h a r a c t e r i z e d in that the tube of the bicycle, preferably the lower tube (20) which is to accommodate the locking device, is formed with a keyhole through which a key (17) may be inserted for operating the lock. 7. A frame for a bicycle for mounting a locking device according to claim 4 or 5, c h a r a c t e r i z e d in that the tube of the bicycle, preferably the lower tube (20) , which is to accommodate the locking device, is formed with a keyhole through which a key (17) may be inserted for operating the lock and at least one, preferably two mounting holes for mounting the end or ends of a locking wire (15) in the wire lock housing or housings (16) in the locking device. 8. A frame for a bicycle according to claim 7, c h a r a c t e r i z e d in that two mounting holes are provided and are axially and radially offset with respect to each other in the frame tube.

Inventors: LARSEN MARTIN VILHELM, LARSEN, MARTIN, VILHELM
Applicants: LARSEN MARTIN VILHELM, LARSEN, MARTIN, VILHELM
Application year: 1998
Main classification: B62H5
IPC codes: B62H5, B62K19