GB2405443A

GB2405443A - Locking bolt

Info

Publication number: GB2405443A
Application number: GB0320354A
Authority: GB
Inventors: Christopher Jones; Malcolm Sworder
Original assignee: STRONGHOLD SECURITY PRODUCTS L
Current assignee: STRONGHOLD SECURITY PRODUCTS L
Priority date: 2003-09-01
Filing date: 2003-09-01
Publication date: 2005-03-02
Anticipated expiration: 2023-09-01
Also published as: GB2405443C; GB2405443B; GB0320354D0

Abstract

A locking bolt comprises a first end part 12 and a second end part 14 with a central section 24 therebetween. Each end part has an enlarged portion. The first and second end parts are securable together by way of a key-operated lock 16 carried by the first part, the first part 12 being separable from the central section. The locking bolt can be used to secure articles such as a trailer hitch lock with the locking bolt spanning the distance between two side walls of the hitch lock and acting to secure the side walls together.

Description

LOCKING BOLT

FIELD OF THE INVENTION

This invention relates to a locking bolt, sometimes referred to as a locking pin.

BACKGROUND TO THE INVENTION

Locking bolts are used to secure certain articles, one article for which a locking bolt is suitable being a trailer hitch lock. In such an application, the hitch lock has an open bottom and is lowered around the hitch of the trailer in known manner. The side walls of the hitch lock have a pair of aligned openings which can receive the locking bolt, the locking bolt passing underneath the hitch and bridging the gap between the aligned openings. When the locking bolt is fitted, the hitch lock and locking bolt together surround a part of the hitch, with the fitted locking bolt preventing the hitch lock from being lifted from the trailer hitch.

The locking the bolt is designed to be difficult and time- consuming to cut through, even with speclialised tools, so .

that unless the locking bolt is unlocked and removed by use of the correct key, it is substantially immovable and so effectively secures the hitch lock to the trailer hitch.

The locking bolt of the present invention, which is shown in the accompanying drawing, shares many features with prior art locking bolts. In particular, the locking bolt is in the form of an elongated bar having a central section and two enlarged ends. One of the enlarged ends is removable so allow the central section to be passed through two aligned openings 2 formed in walls 4 (shown in dotted outline), the locking bar being designed to bridge the gap between the walls 4. When re-fitted, the removable enlarged end may be secured to the remainder of the locking bolt by a key- operated lock. The enlarged ends are designed to be too - 2 large to pass through the aligned openings 2, so that when assembled and locked the locking bolt can either secure the two plates 4 together, or can securely bridge the gap therebetween.

DESCRIPTION OF THE PRIOR ART

One known locking bolt is sold under the trade nature "Bulldog", and has the general structure set out above. The central section of this locking bolt is integral with the first enlarged end, which end is defined herein as the end carrying the key-operated lock. The second enlarged end is removable from the central section, and has a recess which accommodates a part of the central section in the assembled condition. The second enlarged end is securable to the central section by way of two ball bearings which arc carried by the central section and which can project into a" undercut groove formed in the recess of the second enlarged end.

To communicate the locking action from the lock in the first . enlarged end to the ball bearings at the opposed end of the A; central section, the central section is hollow and carries a. :.

locking member. Rotation of the key in the lock causes the locking member to rotate inside the central section. The locking member engages the ball bearings and as it rotates towards its locking condition it forces the ball bearings to move outwardly so as to project beyond the periphery of the central section and into the undercut groove of the recess of the fsecond enlarged end.

To unlock this locking bar the key is rotated towards the unlocking condition, causing the locking member to rotate within the central section and allow the ball bearings to move inwardly until they no longer project into the undercut groove and the second enlarged end can be removed. - 3 -

One disadvantage of the ''Bulldog" locking bolt is the requirement for the locking member to communicate the locking/unlocking action between the lock at one end of the locking bolt and the ball bearings at the other end of the locking bolt. This effectively limits the overall length of the locking bolt and does not allow it to be used in applications requiring a very long locking bolt such as a gateway or the like where such a locking bolt may be desirable.

Another, related, disadvantage is that the central section is necessarily hollow to accommodate the locking member.

Whilst the locking member can be arranged substantially to fill the central section it will nevertheless be easier to cut through the central section of this locking bolt than would be the case if the central section was solid.

A further disadvantage is that the lock body is accessible from the keyway in the first enlarged end of the locking bolt, and is liable to removal through that keyway. Thus, since the lock body is assembled into the first enlarged end through a surface which is subsequently exposed in use, the lock body is vulnerable to attack from that surface, for example by a slide hammer or the like. Thus, means can be utilised to force the lock body out of the first enlarged end of the locking bolt, after which the locking bar is accessible and can be rotated to release the second enlarged end.

STATEMENT OF THE INVENTION

The object of the present invention is to provide a locking bolt which avoids or reduces the above-stated disadvantages.

According to the invention there is provided a locking bolt comprising a first part and a second part, the first and second parts being securable together by way of a key - 4 - operated lock carried by the first part, the first part having a first end portion, the second part having a second end portion, the locking bolt having a central section between the first and second end portions, the first and second end portions being of larger cross-sectional dimension than the central section, the first part being separable from the central section.

Accordingly, the second part and the central section can be integral. Also, since the coupling of the central section to the first part can occur adjacent the first part the central section can be of any desired length, and can be solid throughout substantially its full length.

Preferably, all or most of the lock body of the key-operated lock is located within the first part, the first part having an opening through which the key may be inserted into the ë lock body. Preferably also, the opening is of smallest: cross-sectional dimension that the lock body. Accordingly' . since the lock body cannot pass through the key opening, it is not possible to remove the lock body from the locking bolt by way of a slide hammer for example. .... ë ë

Preferably also, the first part has an opening through which the lock body may be inserted into the first part, the opening being adjacent the central section in the assembled locking bolt. Accordingly, the lock body is assembled into the first part by way of an opening which is obscured in use. Also, it can be arranged that a part of the central section abuts the lock body when the locking bolt is assembled; such abutment can prevent the lock body being forced out of the first part towards the central section.

Desirably, the key-operated lock has a latch which projects radially relative to the longitudinal axis of the lock body, rotation of the key in the lock body causing the latch to be withdrawn into the lock body. Preferably, the latch projects from the lock body substantially at all times, and - 5 - rotation of the key varies the distance by which the latch projects. Desirably, the first part has an opening through which the latch can project; preferably the lock body is retained in the first part by engagement of the latch within the opening.

Preferably, the central section of the second part includes a recess which can accommodate a portion of the first part (and also some or all of of the lock body) in the assembled locking bolt; preferably also the recess has an undercut groove to accommodate the latch of the lock.

DESCRIPTION OF THE DRAWING

The invention will now be described, with reference to the accompanying drawing, which shows the locking bolt according to the invention in partsectional view. . The locking bolt 10 comprises a first part 12 and a second part 14, the first and second parts being separable why desired, but also being securable together by way of a key....

Operated lock 16. ..... :.

The first part 12 has an enlarged end portion 20, and the second part 14 has an enlarged end portion 22. The second part 14 also has a central section 24 which is integral with the enlarged end portion 22, and is of smaller cross- sectional dimension than the end portions 20, 22. In this embodiment the first and second parts 12, 14 are of circular cross-section, so that reference to "dimension" can be interpreted as "diameter".

The first part 12 has a recess 26 which accommodates the lock body 16. The recess 26 continues to the distal end 30 of the first part 12, so that when the first part is assembled the lock body is inserted from the distal end 30.

To allow the key (not shown) to be introduced into the lock - 6 body 16 an opening 32 is provided in the proximal end 34 of the first part 12, the opening being large enough (but preferably only just large enough) to accommodate the key.

Though not shown in this drawing, if desired the security of the locking bolt can be increased by the addition of an anti-drill disc adjacent the opening 32, i.e. a disc which can rotate when engaged by a rotating drill and so prevent the drill cutting into the disc and the lock body 16.

Importantly, the cross-sectional dimension of the opening 32 is smaller than the cross-sectional dimension of the lock body 16, so that the lock body 16 cannot be forcibly removed from the proximal end 34 of the first part 12. This preferred embodiment of the present invention therefore differs from the prior art locking bolts in which the lock body is assembled into the first part from the proximal end ..

and is secured in the first part by a threaded collar or tact: like, it being possible to forcibly remove the lock body.

from the proximal end by way of a slide hammer for example.. -e

The wall 36 which surrounds the recess is a close fit around..

the lock body 16, and acts to reduce or substantially avoided ..

any unwanted relative movement of the lock body 16 within the first part 12. The wall 36 has an opening 40 therethrough, which opening accommodates the latch 42 of the lock The end 44 of the second part 14 has a recess 46 which can accommodate the distal end 30 of the first part 12. The recess 46 has an undercut groove 50 formed therearound, which groove 50 accommodates the latch 42.

The latch 42 is chamferred, and is spring-biassed towards its extended position as shown. The chamfer 52 allows the first part 12 to be assembled to the second part 14 without insertion or rotation of the key. Thus, when the first part 12 is separated from the second part 14, and the key is not 7 - present, the latch 42 assumes the position shown in the drawing; as the distal end 30 of the first part 12 is pushed into the recess 46 of the second part 14 the chamfer 52 engages the edge of the recess and causes the latch to be partially pressed back into the lock body 16. The latch 42 then slides along the inside of the recess until the first part 12 and second part 14 are in their assembled positions as shown, whereupon the latch 42 snaps out to engage the undercut groove 50. It will be understood that insertion (and preferably also rotation) of the correct key (not shown) into the lock body 16 is required to release the latch 42 from the undercut groove 50 and allow separation of the first part 12 from the second part 14.

In the assembled condition of the locking bolt 10 as shown, the first part 12 substantially fills the recess 46, and in practice little or no gap would preferably exist between the lock body 16 and the bottom of the recess 46. In they: absence of any substantial gap (a substantial gap being shown in the drawing for clarity), any attempt to force the lock body 16 out of the first part 12 in the direction 0.

the central section 24 will be resisted by engagement of the lock body 16 with the bottom of the recess 46. . :e

It will be understood that since the lock body 16 is located in the first part 12, and the first part 12 is separable from the central section 24, the central section 24 can be solid, which reduces the cost of manufacturing the central section, and also maximises its resistance to being cut through. Also, the central section can be made as long as desired for the application, it merely being necessary to use a solid bar of appropriate length from which to make the second part 14. A common design of first part 12 can if I desired be used with different length second parts (or more particularly second parts with different length central sections), so reducing the complexity of manufacturing locking bars for different applications. - 8 -

In this embodiment the enlarged end 22 of the second part 14 is integral with the central section 24, and whilst that is preferably it is not essential since these parts could be made separately and subsequently (permanently) joined together.

It will therefore be understood that the known methods of seeking to disable the locking bolt are resisted by the present invention. Thus, attempts to force the lock body out of the first part (towards the proximal end 34) is resisted by the opening 32, which by virtue of its small size allows the insertion of only a small tool, and avoids the possibility that the lock body 16 can be forced therethrough. Attempts to force the lock body out of the first end towards the distal end 30 are resisted by the engagement of the lock body 16 with the bottom of the recess 46, in other words with a solid surface provided by the central section 24. Attempts to force the first part 1: away from the second part 14 are resisted directly by the latch 42 engaging the undercut groove 50, and the latch and groove can (and will) be constructed to resist such forcing separation.

The locking bolt 10 is also of extremely simply construction, and can be assembled from only three separate components. This simplicity is achieved by utilising the latch 42 to secure the lock body 16 to the first part 12.

Thus, in the embodiment shown the latch 42 cannot be fully retracted into the lock body 16 by rotation of the key; since the latch will always project into the opening 40 its engagement with the wall of the opening 40 maintains the lock body 16 within the recess 26, and as above indicated the lock body is preferably a substantially tight fit into the recess 26, so any tendency to fall out of the recess is in any event very small or insignificant.

When assembling the lock body 16 into the first part 12 it is however necessary that the latch 42 be fully retracted - 9 - into the lock body 16, and it is arranged that the latch 42 can be pushed back into the lock body against the force of its biassing spring so that it does not project therefrom, allowing the introduction of the lock body 16 into the recess 26. If it is desired subsequently to remove the lock body from the recess 26 a suitable tool can be used to force the latch 42 fully into the lock body 16.

- ace. . ë ace.. e. . -

Claims

CLAIMS I

1. A locking bolt comprising a first part and a second I part, the first and second parts being securable together by way of a key-operated lock carried by the first part, the first part having a first end portion, the second part having a second end portion, the locking bolt having a central section between the first and second end portions, the first and second end portions being of larger cross-sectional dimension than the central section, the first part being separable from the central section.

2. A locking bolt according to claim 1 in which the second part and the central section are integrally formed.

3. A locking bolt according to claim 1 or claim 2 in which all or most of the lock body of the key-operated lock is located within the first part, the first part having a key opening through which the key may be inserted into the lock body.

4. A locking bolt according to claim 3 in which the key opening has a cross-sectional dimension smaller than that of the lock body so that the lock body cannot pass through the key opening.

5. A locking bolt according to any one of claims 1-4 in which the first part has a second end opposed to its first end portion, and has an opening in the second end through which the lock body may be inserted into the first part.

6. A locking bolt according to claim 5 in which a part of the central section lies adjacent to the opening in the second end of the first part when the locking bolt is assembled, and that part of the central section can abut the lock body within the first part.

7. A locking bolt according to any one of claims 1-6 in which the keyoperated lock has a latch which projects radially relative to the longitudinal axis of the lock body, rotation of the key in the lock body causing the latch to be withdrawn into the lock body.

8. A locking bolt according to claim 7 in which the latch projects from the lock body substantially at all times, and rotation of the key varies the distance by which the latch projects.

9. A locking bolt according to claim 8 in which the first part has a latch opening through which the latch can project, and the lock body is retained in the first part by engagement of the latch within the latch opening.

10. A locking bolt according to any one of claims 7-9 in which the latch is resiliently biassed outwardly of the lock body, and in which the latch is chamferred.

11. A locking bolt according to any one of claims 1-10 in which the central section of the second part includes a recess which can accommodate a portion of the first part in the assembled locking bolt.

12. A locking bolt according to claim 11 in which the recess has an undercut groove to accommodate the latch of the lock.

13. A locking bolt according to Claim 12 in which the undercut groove is annular.

14. A locking bolt according to any one of claims 11-13 in which, with the exception of th recess, the central section is solid substantially throughout its full length. - 12

15. A locking bolt constructed and arranged substantially as described in relation to the accompanying drawing.