GB2431197A

GB2431197A - Lock with casing and blocking member that prevents access to a connector

Info

Publication number: GB2431197A
Application number: GB0619024A
Authority: GB
Inventors: Christopher John Fryer
Original assignee: ALBERT JAGGER Ltd
Current assignee: ALBERT JAGGER Ltd
Priority date: 2005-10-12
Filing date: 2006-09-27
Publication date: 2007-04-18
Anticipated expiration: 2026-09-27
Also published as: GB2431197B; GB0520681D0; GB0619024D0

Abstract

A lock for preventing access to a connection part of a member (10) comprising a casing for placing over at least part of the member (10) and an element, such as a rod (21, 22) including a recess (25, 26). The element (21, 22) is biased to a first position in which said recess is at least partly out of alignment with a blocking member, which may be a ball-bearing (32), and being movable to a second position in which said recess is aligned with the blocking member (32). Locking means are provided at least partly within the casing for preventing movement of the element from its first to its second position. In use, with the element in its second position, the lock can be engaged with said member, which is thereby keyed to the casing by said element moving to its first position. The lock is released by actuation of the locking means effecting removal of said keying. The lock may prevent unauthorised access to a nozzle (10) forming part of an airbrake coupling on a commercial vehicle trailer.

Description

This invention relates to a lock, particularly, but not exclusively, for

preventing unauthorised access to a nozzle forming part of an airbrake coupling on a commercial vehicle trailer.

As is well known, conimercial vehicle trailers are designed so that they can be hitched to any type of suitable tractor unit' as required by means of a relatively simple connection. In particular the airbrake system of the tractor unit' is engaged, during the hitching process, with a nozzle disposed at the front of the trailer. Until this engagement takes place, the brakes of the trailer are held on, so that the trailer is immobile.

Many such trailers are parked overnight in compounds, by the side of the road, in lay-bys and in lorry parks all around the country. Although some king-pin type locking devices are known, these are generally unsatisfactory, and thus at present, in practice, it is possible for anyone to drive up to a trailer with a tractor unit and hitch up the trailer thereto. This is of a particular concern at airports and fuel depots where the trailers may be for fuel tankers, and where accordingly it is important to prevent them being stolen by terrorists.

An object of the invention is to provide a lock, principally for a connector of a commercial vehicle trailer, in an efficient and convenient form.

According to the present invention there is provided a lock for preventing access to at least a connection part of a member, the lock comprising a casing for placing over at least part of the member, in use, thereby to prevent access to at least said connection part thereof, there being within the casing an element with a recess in part thereof, the element being biased to a first position in which said recess is at least partly out of alignment with a blocking member and being movable between said first position and a second position in which said recess is aligned with the blocking member, there being locking means at least partly within the casing for preventing movement of the element from its first to its second position, the arrangement being such that, in use, with the element in its second position the lock can be engaged with said member which is thereby keyed to said casing by said element moving to its first position, release of the lock from the member thereafter being by actuation of the locking means effecting removal of said keying.

Preferably the element is a linearly slidable rod. More preferably two elements are provided at diametrically opposite positions in the casing.

Conveniently the locking means is a key operated lock device at one closed end of the casing. Desirably the lock device includes an angularly movable cam which is engaged by the or each element. The cam is also movable axially of the casing and is preferably biased in opposition to the or each element. The cam has at least one ramped cam surface.

Preferably when the member is keyed to the casing, in use, part of the or each blocking member is received into an exterior circumferential groove of the member.

The member is, in one embodiment, in the form of a nozzle.

Advantageously the blocking member is a ball-bearing. In one embodiment the casing comprises an outer metal sleeve, preferably of steel, and an inner element of aluminium. The locking means may be secured to the outer sleeve against relative rotation thereto by at least one radial plug or pin.

The invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is an exploded perspective view of a lock of the invention, with a nozzle of a vehicle trailer airbrake coupling shown in position for engagement therewith, Figure 2 is an enlarged perspective view of a cam member of the lock, Figure 3 is a side view of the lock of Figure 1 engaged with the nozzle, Figure 4 is a cross-sectional view on the line 4-4 of Figure 3, Figure 5 is a side view of the lock of Figure 1 with a key engaged therein and with the lock released from the nozzle, Figure 6 is a cross-sectional view on the [me 66 of Figure 5, and Figure 7 is a view like Figure 1, for an alternative embodiment of the invention, and Figure 8 is an enlarged perspective view of a cam member of the lock of Figure 7.

As mentioned in the introduction to the specification, the main application for a lock of the invention is with a commercial vehicle trailer, and in particular the prevention of unauthorised access to a nozzle forming part of an airbrake coupling of the trailer. Such a nozzle, which is identified by the numeral 10 in Figures 1 and 3 to 6, has an externally frustoconical front portion 11 and a hexagonal external rear portion 12. The end of the rear portion 12 is generally connected to a line of an airbrake system which actuates the respective brakes of the wheels of the trailer, and as this is of standard form, no further reference would be made thereto. It is however to be noted that when the nozzle 10 is uncoupled from a tractor unit for use with the trailer, the brakes of the trailer are held on, so that the trailer is immobile.

As can be seen from the Figures, between the hexagonal portion 12 and the frustoconical portion 11 the external surface 13 of the nozzle lOis cylindrical, with a generally semi-circular section annular groove or recess 14 formed therein at its junction with the frustoconical portion 11. Finally it will be noted that there is an annular radially extending step surface between the cylindrical surface 13 and the hexagonal portion 12.

The lock itself is, in this embodiment, formed with a casing comprising an outer hollow cylindrical sleeve 15 preferably of stainless steel.

Extending within the sleeve 15 from one end thereof, shown as the left hand end in the Figures, is a hollow generally cylindrical inner casing part 16 which may be of aluminium, which alternatively could be of stainless steel.

The central circular section bore 17 through the part 16 is stepped down just short of its longitudinal mid-point to form an inwardly extending frustoconical stop surface 18.

This stepping down of the bore is effected by increasing the inwards radial extent of the inner casing part 16 as shown best in Figures 4 and 6, and in this increased radial extent part, at diametrically opposite positions, two circular-section bores 19, 20 respectively are provided, the central axis of each bore lying parallel to the central axis through the sleeve 15. Each bore extends from a position just beyond the stop surface 18 to the end of the radially inwardly extended portion of this part 16.

Received as close sliding fits in said bores 19, 20 respectively, are respective elongated circular-section rods 21, 22. Each rod is longer than its associated bore 19, 20 respectively so that the respective ends of the rods extend out of said bores and thus out of the inner casing part 16 as shown best in Figures 4 and 6. Respective coiled compression springs 23, 24 are received in the bores 19, 20, so as to bias the rods 21, 22 in a direction out of their associated bores 19, 20.

As shown best in Figures 4 and 6, the rods are formed with respective circumferential grooves 25, 26, each groove being spaced axially a short distance from the end of the rod at which the end of the compression spring 23 or 24 is received. Each groove is of generally semi-circular section, but has a lead-in surface for a purpose to be described hereinafter, these lead-in surfaces being shown by the numerals 27, 28 respectively for the rods 21, 22.

At the axial position opposite the groove 14 of the nozzle 10 when it is inserted into the lock as shown in Figure 4, the radially inwardly extended portion of the inner casing part 16 is provided with two diametrically opposed circular section through bores 29, 30 respectively, each bore extending from the inner surface of the casing part 16 to the bore 19 or 20 formed therein. Respective ball bearings 31, 32 are received in the bores 29, with respective parts thereof being receivable into the groove 14 or being clear thereof as will be described hereinafter to lock the nozzle 10 to the lock casing or to release it therefrom. It will be noted that in the fully extended position of the rods 21, 22 shown in Figure 4, the ball bearings are partly received in their associated bores 29, 30 and partly in the groove 14 given that the circumferential grooves 25, 26 of the rods 21, 22 are out of axial alignment with the bores 29, 30. However as will be described, when the grooves 25, 26 are aligned with the bores 29, 30 respectively upon movement of the rods 21, 22 against their respective biasing springs, the ball bearings can move radially outwardly so as to be partly received in their associated grooves 25, 26, and partly in their respective bores 29, 30, so that the ball bearings are clear of the nozzle groove 14, so as to allow the lock to be separated therefrom.

Instead of two detents, i.e. the ball bearings 31, 32, only one detent, or more than two detents, of the same or a different form, could be used.

The outer cylindrical sleeve 15 of the lock is closed at its one end, its right hand end shown in Figures 1 and 4 to 6, by locking means. A first part of the locking means in the form of a cylindrical end plug 33 which is arranged to be flush with the end of the sleeve and is held against relative rotational and axial movement by a suitable number of equiangularly spaced radial pins, one of which 34 is shown in Figure 1, each pin being in a bore in the plug and having its outer end extending into a recess (not shown) in the interior surface of the sleeve 15. At the central axis of the plug 33, there is disposed a rotational lock plug 36 which is formed at its outer accessible end with formations which are engageable by the correct key associated with the locking means, so that when the correct key 36a is engaged with the lock plug 36, the lock plug can be turned. An inner end of the lock plug is non- rotatably engaged, by way of a flat sided projection, with a cam member 37 against respective cam surfaces of which the respective free ends of the rods 21, 22 engage. Finally, the cam member 37 is biased by a compression spring 38 in a direction away from the lock plug 36, the spring 38 being weaker than the springs 23, 24.

As shown best in Figure 2, the cam surfaces provided on the inner face of the cylindrical cam member 37 each extend for 900, each surface comprising a short flat part 37a leading to a Continuous ramp surface 37b.

Accordingly it will be understood that as the cam member is angularly moved in one direction by the plug 36 and key 36a, the respective ends of the rods 21, 22 which engage the cam surfaces are moved linearly against their associated springs, the axial position of the cam member remaining constant.

Before the lock is engaged on the nozzle 10, it is in an unlocked state, in which the key is not engaged with the locking means. In this state the rods 21, 22 are retracted against their respective springs 19, 20 by the inward bias on the cam member, so that the respective grooves 25, 26, are axially aligned with the bores 29, 30. Thus although the ball-bearings 31, 32 are sized to prevent them moving out of their associated bores 29, 30 into the bore 17, these ball-bearings are free to move between the Figure 4 position, without the nozzle 10 in place, and the position where no part of the ball-bearing protrudes into the bore 17. Thus the ball bearings are loose'. In this unlocked position of the lock, the spring loaded cam member 37 would be at its innermost position, i.e. with its inner end adjacent the inner end of the radially inwardly extended portion of the part 16.

When the lock is engaged on the nozzle 10, it is pushed over it until the position shown in Figure 4 is reached, where, as shown, the rear end of the nozzle 33is spaced slightly axially inwards of the open end of the casing of the lock. On pushing the lock onto the nozzle to this position, the forward tapered end of the nozzle engages the cam member 37 and forces the cam member 37 rearwardly against its spring towards the plug 33. This releases the retracted rods 21, 22 which thus then automatically extend under the biasing forces of their respective springs 23, 24. This extension of the rods moves the grooves 25, 26 out of axial alignment with the bores 29, 30 respectively and as a result the ball bearings are engaged by the lead-in surfaces 27, 28 respectively as the rods extend, so as to force the ball bearings to the position shown in Figure 4, where parts of the ball bearings respectively are received in the groove 14 in the exterior surface of the nozzle thereby keying the nozzle and the lock together. In this position, shown in Figure 4, it is only possible to remove the lock from the nozzle by means of the correct key operating the locking means and thus a secure and effective means of preventing a trailer being hitched up to a tractor unit by coupling the airbrake system of the tractor unit to the nozzle 10 of the trailer.

If the correct key is now inserted into the lock plug 36, and rotated, the corresponding rotation of the cam member 37 connected to the plug 36 causes the free ends of the respective rods 21, 22 to move along the cam surface 37b, which results in the two rods being retracted to the left as shown in Figure 4, i.e. against the bias of their respective springs 23, 24. As the rods retract, the grooves 25, 26 respectively of the rods 21, 22 move into axial alignment with the respective ball bearings 31, 32. As this occurs the spring force on the cam member 37 is acting thereon to move it to the left as shown in Figure 4, and as a result the force on the nozzle 10 by the cam results in the ball-bearings being forced radially outwardly of the groove 14, with the result that the lock springs' out of engagement with the nozzle and disengages therefrom, the lock thus moving to the right as shown in Figure 4 relative to the fixed nozzle 10. This released' position is shown in Figure 6, the lock now being removable from the nozzle.

Once the lock has disengaged from the nozzle, the force of the springs 23, 24 cause the rods to move to their extended positions against the bias acting on the cam member 37, with the result that with the key still in its inserted and turned position the ball-bearings are again forced to the positions respectively shown in Figure 4, but with no nozzle now inserted in the lock.

In this locked' state of the lock, it is not possible to place it over a nozzle 10. Firstly the key must be turned back to its position of insertion, this - 10 - turning of the key and thus of the cam member 37 with its cam surfaces 37b retracting the rods so that when the key is extracted from the lock plug 36 in the unlocked' state of the lock, the ball-bearings would again be loose' between the groove 14 and the respective grooves 25, 26 of the inner casing part 16. In this state the lock is thus again ready to be engaged on a nozzle and the process repeated as set out above.

With regard to the keys, these would normally be of the high security type, and the lock could be keyed in sets so that authorised drivers of the tractor units alone would be able to undo locked' trailers where the locking is by means of a lock of the present invention. There could also be a master key holder as required.

It will be understood that locking members other than ball-bearings could be used to key the nozzle to the lock casing and it will also be understood that a lock of the invention has applicability to the locking' of members other than nozzles. Indeed a lock of the invention can be used to prevent access to a member in general, and particularly to a connection part of said member.

Although a single nozzle on the trailer has been described in the introduction, it is known to provide two nozzles, one for the main airbrake line and one for an auxiliary airline. The lock of the invention could be used with either nozzle. It will be understood that a single rod, or more than two rods, or one or more suitable alternative elements, could be used.

- 11 - Figure 7 shows an alternative embodiment of a lock of the invention.

Principally it differs from the embodiment of Figures 1 to 6 in that instead of there being two rods 21, 22, this alternative embodiment utilises three rods 39, 40, 41 received in respective equi-angularly spaced bores in the inner casing part 16a. Correspondingly, three blocking members, in the form of ball bearings, are provided, whilst instead of the cam member 37 with its two cam surfaces, the cam member 42 of this alternative embodiment is provided with three equi-angularly spaced cam surfaces, each comprising a flat part 43 and a ramp surface 44, as shown best in Figure 8. Finally, the sleeve 15a of the lock is provided with three equi- angularly spaced indents, two of which are illustrated at 45 in Figure 7. The provision of these indents improves security, for example by preventing the breaking open of the lock by the use of an industrial pipe cutter.

Despite the changes made to the lock design to incorporate three rods instead of two, the lock of Figure 7 operates in the same manner as for the two rod version.

An 0' ring 46 shown in Figure 7 to prevent ingress of water to the casing part of the lock could also similarly be provided in the Figures 1 to 6 embodiment.

Claims

- 12 - Claims 1. A lock for preventing access to at least a connection

part of a member, the lock comprising a casing for placing over at least part of the member, in use, thereby to prevent access to at least said connection part thereof, there being within the casing an element with a recess in a part thereof, the element being biased to a first position in which said recess is at least partly out of alignment with a blocking member and being movable between said first position and a second position in which said recess is aligned with the blocking member, there being locking means at least partly within the casing for preventing movement of the element from its first to its second position, the arrangement being such that, in use, with the element in its second position the lock can be engaged with said member which is thereby keyed to said casing by said element moving to its first position, release of the lock from the member thereafter being by actuation of the locking means effecting removal of said keying.
2. A lock as claimed in Claim I, wherein the element is a linearly slidable rod.
3. A lock as claimed in Claim 1, wherein two elements are provided at diametrically opposite positions in the casing.
4. A lock as claimed in Claim 3, wherein each of the elements is a linearly slidable rod.

- 13 -
5. A lock as claimed in any one of the preceding claims, wherein the locking means is a key operated lock device at one closed end of the casing.
6. A lock as claimed in Claim 5, wherein the lock device includes an angularly movable cam which is engaged by the or each element.
7. A lock as claimed in Claim 6, wherein the cam is also movable axially of the casing.
8. A lock as claimed in Claim 7, wherein the cam is biased in opposition to the or each element.
9. A lock as claimed in any one of Claims 6 to 8, wherein the cam has at least one ramped cam surface.
10. A lock as claimed in any one of the preceding claims, wherein the blocking member in or out of alignment with the recess in the or each element is a ball-bearing.
11. A lock as claimed in any one of the preceding claims, wherein the casing comprises an outer metal sleeve.
12. A lock as claimed in Claim 11, wherein the sleeve is of steel.
13. A lock as claimed in Claim 11 or Claim 12, wherein the casing comprises an inner element.

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14 - 14. A lock as claimed in Claim 13, wherein the inner element is of aluminium.
15. A lock as claimed in any one of Claims 11 to 14, wherein the locking means are secured to the outer sleeve against relative rotation thereto.
16. A lock as claimed in Claim 15, wherein the locking means are secured to the outer sleeve by at least one radial plug or pin.
17. A lock as claimed in Claim 2, wherein three elements are provided at equi-angularly spaced positions in the casing.
18. A lock as claimed in Claim 17, wherein the lock device includes an angularly movable cam which has three equally-angularly spaced ramped surfaces engaged in said second position by said rods respectively.
19. A lock as claimed in any one of the preceding claims, wherein when the member is keyed to the casing, in use, part of the or each blocking member is received into an exterior circumferential groove of said member.
20. A lock as claimed in any one of the preceding claims, wherein said member is in the form of a nozzle.
21. A lock as claimed in any one of the preceding claims, when engaged with said member.
22. A lock for preventing access to at least a connection part of a member, substantially as hereinbefore described, with reference to, and as shown in the accompanying drawings.