GB2141170A - Bicycle lock - Google Patents

Abstract

A bicycle lock of the type comprising a shackle 1 and a cross bar 3, in which a locking device eg a barrel lock 4 housed in the cross bar operates bolts 10 therein to lockingly engage both ends of the shackle. <IMAGE>

Description

SPECIFICATION Bicycle lock The present invention relates to bicycle locks of the type comprising a 'U'-shaped shackle lockable into a cross bar, and will be described as such, although it will be clear that the lock is not iimited in application to securing bicycles.

Bicycle locks of the type being discussed have been available for some time but have suffered from a number of disadvantages which the present invention seeks to overcome. Thus, for example, the shackles and cross bars have been made of natural state steels and could readily be cut; the lock elements have commonly been of simple design and readily pickable. Other locks, suchas that in U.S. patent 4,155,231, can be forced apart by placing a jack between the two limbs of the shackle; the weakness of locks of this type arises from the geometries of the shackle end which is not retained by the lock element and the associated aperture in the cross bar.

A principal feature of the present invention is that a high integrity barrel lock is positioned centrally in the cross bar and operates latches within the cross bar which lockingly engage both ends of the 'U' shackle.

A number of embodiments of the present invention will now be described with reference to the accompanying drawings in which: Figure 1 is a sectional side elevation Figure la is a plan view of Fig. 1 Figure 2 is an enlarged detail of Fig. 1 Figure 2a is a view of Fig. 2 in direction of arrow A.

Figure 3 is a sectional side elevation of a further embodiment.

Figure 4 is a sectional side elevation of a further embodiment.

Figures 5, Sa show two views of details of a further embodiment.

Referring to Fig. 1, shackle 1 is preferably of circular cross section tubular steel, and is heat treated to resist normal cutting tools such as hacksaws. The legs are preferably parallel, at least at their ends. Other cross sections could be used, and the shackle could be of solid section.

An aperture 2 is formed in the inside surface of the end portion of each leg of the shackle 1, and their purpose is to lockingly receive the ends of latches 10 housed in a cross bar 3. The precise design of apertures 2 will depend upon the sections used for the shackle 1 and cross bar 3, and the shape of the engaging portion of the latches.

The cross bar 3 is preferably a square cross section steel tube, suitably heat treated to be resistant to cutting, for example by a hacksaw. It may alternatively be of any convenient hollow cross section. Two mutually parallel holes are formed, one towards each end portion of the cross bar, to receive the end portions of the shackle 1, and are of a shape corresponding to the shackle end portion cross section.

A locking device 4, such as a key operated barrel lock, is located in the cross bar 3, preferably in the centre thereof, and preferably such that access thereto is on the opposite side of the cross bar 3 to the side in which the shackle receiving apertures are formed.

The important features of the locking device are that it shall have a high integrity unlocking function, be readily securable into the cross bar, and have a mechanical drive output suitable for operating latches or the like. One such device, and the one described in relation to Fig. 1, is commonly known as a barrel lock. When a correct key is inserted in the lock and rotated, corresponding rotation is effected of an output drive shaft of noncircular cross section.

Assembly of the barrel lock 4 to the cross bar will now be described with reference to Figs. 2, 2a. A tube 5 is welded (as at 16) into a hole in the side of cross bar 3, and acts as a housing for the barrel lock 4. The outer portion of the barrel lock 4 is non rotatably retained in the lock housing tube 5 by means of a pin 6 which passes diametrically through the lock housing tube 5 and terminates in the outer non rotating portion of the barrel lock 4.

Note that, with reference to Fig. 2a, because the lock housing tube 5 is enclosed within cross member 3, it is necessary to first drill though the face of cross bar 3; for convenience, the pin is made long enough to fulfil its function of pinning items 4 and 5 to each other and also, through machining it off, to flush fill the access hole formed in the cross bar 3. As an alternative, an epoxy type adhesive, or soldering could be used to secure the barrel lock in the housing tube 5, although it should be noted that if the means of fixing the barrel lock into the housing tube fails before a false key or the lock itself fails, then the resultant ability to rotate the entire lock would release the shackle.

Referring again to Fig. 2, the output shaft 7 from the barrel lock 4 is of non-circular cross section and engages a corresponding hole in a latch actuator 8 rotatably housed in the end of lock housing tube 5. Peg-like protruberances preferably integral with latch actuator 8 engage apertures in the ends 9 of the latches 1 0. Thus, rotation of a matching key in barrel lock 4 will engage and disengage latches 10 in apertures 2 in the shackle 1, by causing longitudinal movement of the latches.

The relationship between the latch ends and the shackle will now be described with reference to Figs. 1 and 1a. In this embodiment, the tubular cross bar is of square cross section and slidingly houses two latches 10 fabricated from square section steel tube. Outer ends 11 of latches 10 are cut off at an angle as illustrated, thus forming a lip 12 which, in the locked position, engages in a slot 1 3 cut in the end portion of shackle 1. Slot 1 3 corresponds of course to the general references earlier to the aperture 2.

The importance of correctly angling end 11 of the latches should be noted in relation to security. A common theft mode is to apply force in directions of arrows B by means of a jack; on many known locks, deformation of the shackle in this way will separate shackle from cross bar. However, referring to Fig. 1, the shackle would clearly use point 1 4 as a fulcrum; provided the cutaway at 11 is of sufficient angle, the bottom of the shackle, following path of arrow C, will pass freely inside tubular latch 10 and place no strain on any portion of the locking mechanism.

The latch ends 9 which engage the protruberances on the latch actuator 8 are preferably formed by machining away appropriate parts of the square tube section of the latches 10, as illustrated at 15, Fig. 1.

In a modification, illustrated in Fig. 3, shackle ends 20 pass right through cross bar 3, the full section of square tube latch 10 forms the engaging lip 12, and the aperture 2 in the shackle 1 is of size corresponding to the square tube latch.

Note that, in the embodiments of Figs. 1 and 3, it is not possible to force the latches by hammering a drift through the open ends of cross bar 3 because the apertures 2 are blind; however, to prevent ingress of water and dirt to the locking mechanism, end plugs 21 may be fitted in the ends of the cross bar.

Fig. 4 illustrates a further embodiment of the present invention. In this alternative, latches 10 are in the form of round pins supported in bushes 31, and engage in blind circular holes 2 in the shackle 1. Operation of the barrel lock rotates a cam 32; latches 10 are withdrawn, on unlocking, by means of springs 30.

Other modifications to the embodiments described will be apparent; thus, for example, instead of using springs 30 to withdraw the pin type latches, the pins could be linked to a latch actuator to provide positive drive of the latches in both directions.

The modification illustrated with reference to Figs. 5, 5a differs essentially from that described with reference to Fig. 1 in that only one latch is used, although both ends of the shackle are engaged. The lock as a whole is similar and so only the major differences will be explained.

The pair of apertures 2 formed one in the end portion of each shackle leg are asymmetric, one being in the outer surface and the other in the inner surface. The two latches 10 are replaced by a single latch 40, having a rectangular hole 41 in each end portion thereof. Relative sizes next to be explained ignore working clearances and tolerances. The width of the hole corresponds to the diameter of the shackle, and the length of the hole corresponds to the diameter of the shackle plus the depth of the aperture 2. As illustrated in Figs. 5 and 5a, the locked portion is achieved by having moved the latch 40 to the right inside the cross bar (not shown) by means of the barrel lock 4 and the latch actuator 8. Thus, end walls 42 of apertures 41 engage lockingly with apertures 2. Opposite rotation of the barrel lock 4 will drive the latch 40 to the left as illustrated, thus disengaging end walls 42 from apertures 2 and allowing exit of the shackle ends from holes 41 in the latch 40.

In considering the more general aspects of the present invention, it will be apparent that, without departing from the invention, by choosing appropriate sizes of shackle and cross bar, locks in accordance with the invention could be used for securing, for example, motorcycles, motor vehicles by passing the cross bar through a wheel, and so on.

Claims (10)

1. A lock of the type comprising a shackle and a cross bar, the cross bar having apertures therein adapted to lockably receive end portions of the shackle, and a lock element situated in the cross bar, characterized in that actuation of the lock element causes both ends of the shackle to be lockingly retained in the cross bar.

2. A lock as claimed in claim 1, in which the cross bar houses two latches actuated by the lock element, the two latches each engaging one end of the shackle.

3. A lock as claimed in claim 1, in which the cross bar houses a single latch actuated by the lock element, the latch having end portions adapted to engage the end portions of the shackle.

4. A lock as claimed in any preceding claim, in which the lock element is housed in the central portion of the cross bar.

5. A lock as claimed in any preceding claim, in which the lock element is a barrel lock of the type having a non circular output shaft adaptable to translate key rotation into longitudinal latch movement.

6. A lock as claimed in claim 5, in which the barrel lock is secured in a correspondingly shaped housing tube welded into the cross bar.

7. A lock as claimed in claim 6, in which the barrel lock is secured in its' housing by means of a pin.

8. A shackle adapted to be used in association with a cross bar, to form a lock in accordance with any preceding claim.

9. A cross bar adapted to be used in association with a shackle, to form a lock in accordance with any of claims 1 to 7.

10. A lock substantially as described in the accompanying specification.