GB2528613A

GB2528613A - Trailer protection system

Info

Publication number: GB2528613A
Application number: GB1519769.2A
Authority: GB
Inventors: Matthew John Timmis
Original assignee: Individual
Current assignee: Individual
Priority date: 2011-06-09
Filing date: 2011-07-01
Publication date: 2016-01-27
Anticipated expiration: 2031-07-01
Also published as: GB201111273D0; GB2493495A; GB201519769D0; GB2528613B; GB201109612D0

Abstract

The purpose of this invention is to protect a trailer by preventing accidental damage to articulated lorry trailers caused by the tractor unit pulling away when the trailer landing legs are not lowered as they should be when the trailer is to be parked. The invention provides an interlock system, the system comprising: a means that indicates the operational state of a trailer landing leg and whereby the system, responsive to the state of the trailer landing leg, constrains the release of the hitch coupling between the tractor unit and trailer, thereby preventing inadvertent release of the trailer if the trailer landing leg is not extended to its operative state. Extension may involve a lower leg 2 telescopically moving relative to an upper leg (1 see fig 1), revealing an aperture 3 and a key (7a see fig 3) for unlocking a padlock (10 see fig 7) for the coupling. A latch (6 see fig 3) for allowing leg retraction can only be operated when the key (7a) is inserted.

Description

Trailer Protection System

Field of the Invention

The present invention concerns a novel device for protecting trailers, primarily articulated lorry trailers / Heavy Goods Vehicle (HGV) trailers, against accidental dropping and associated damage as arises from inadvertent decoupling at the trailer's tow coupling /hitch when the trailer landing legs (front support legs) are not in place.

Background of the Invention

Of the myriad difficulties faced by lorry drivers, and especially novice drivers, of articulated lorries / trailer type HGVs one major problem is ensuring proper, safe deployment of the front support legs of the trailer of the articulated lorry I HGV at all times whenever the trailer is uncoupled from the cab (tractor unit).

Whereas when the trailer is parked and uncoupled from the tractor unit it needs to be supported at the front (hitching end) of the trailer by telescopic or articulated extended front support legs on the trailer, those legs need to be retracted when the trailer is to be driven away. All too often inexperienced HGV drivers can mistakenly think they have properly deployed the support legs when parking the trailer, unhitch and drive away only to find the trailer front end crashing to the ground behind them. The drop can cause considerable damage to the trailer and to goods held in the trailer. For refrigerated container trailers the damage can run into tens of thousands of pounds and for trailers containing fragile goods such as, for example, crate-loads of wine and spirit bottles the damage can be considerably more expensive still.

In the commonest HGV trailer hitching arrangement when the trailer is properly coupled to the tractor unit, the tractor unit normally supports the weight of the trailer on a horizontal support plate! horse shoe-shaped coupling device on the bed of the tractor unit that is known as the fifth wheel'. When the trailer is correctly hitched to the tractor unit a pin, known as the king pin, on the trailer locates in a socket at the centre of the fifth wheel and is positively located and locked in place by a latch that closes behind the pin securing the trailer to the tractor unit. A safety clip is manually applied as an auxiliary pad of the locking mechanism constricting the release handle to prevent accidental release of the hitch and confirm proper hitching coupling. It passes through a safety clip aperture of the fifth wheels locking mechanism that is only open! usable when the king pin from the trailer is properly inserted and engaged in the hitch coupling socket of the fifth wheel on the tractor unit. This standard locking mechanism! safety clip arrangement generally ensures correct coupling but is, however, unable to prevent a novice (or tired) driver from encountering the problem scenario described above.

Although many systems exist for double locking trailer hitches or locking trailer jacks or support legs (eg of caravans), these are all basically just anti-theft systems. US3780546 uses a lock on a trailer hitch to prevent use of the hitch without a key. US7584677, GB9722096 and US2003233858 all concern a lockable clutch or ratchet for a trailer jack preventing trailer theft by preventing unauthorized persons without a key from raising! retracting the jack of the parked trailer. Similarly GB042341 1 concerns use of a padlock on a caravan corner support leg to prevent a thief from raising the leg to prevent theft of the caravan. These do not address the trailer dropping problem described above and do nothing to stop such problems from occurring. The driver with such a key is able to lock the trailer legs down after lowering them but that is not automatic and does not save the driver from the risk of forgetting to lower the trailer landing legs and the trailer subsequently dropping as discussed above.

There remains a need for a simple, effective solution to the problem scenarios described above, substantially removing the risk of accidental trailer dropping. It is an objective of the present invention to provide such a solution.

Summary of the Invention

According to a first aspect of the present invention there is provided an interlock system for trailers, primarily articulated lorry trailers! HGV trailers, where the trailer hitches by a hitch coupling to a tractor unit that tows the trailer and the trailer has at least one landing leg to support the trailer front end when parked and uncoupled from the tractor unit, the system protecting against inadvertent dropping of the trailer, the system comprising a signaling means that indicates the operational state of the trailer landing leg and whereby the system, responsive to the state of the trailer landing leg, constrains the release of the hitch coupling between the tractor unit and trailer preventing inadvertent release of the trailer if the trailer landing leg is not extended to its operative state.

Preferably the signaling means is mounted in or on the landing leg.

In one preferred embodiment the signaling means comprises a key-holder holding a release key to release a lock on the hitch coupling, the key-holder being configured for the key to be substantially only accessible when the trailer landing leg is extended to its operative state. In this embodiment the key operated lock for the hitch coupling forms part of the system. Preferably the key operated lock is used in place of the confirmatory safety clip of existing hitch couplings and has a member that extends through the safety clip aperture. The lock maybe a padlock and where the lock member is the hoop of the padlock.

Preferably the key operated lock is of a type that has key retention so that when the lock is closed the key can be removed but is retained when the lock is open. Since the key can only be removed from the lock and transferred to the landing leg to raise the landing leg when the lock is closed and the lock can only be closed in the place of the safety clip when the hitch coupling is properly engaged, the proper engagement of the hitch coupling before retracting the landing legs is substantially ensured.

Preferably the key-holder is mounted within a chamber in a part of the trailer leg.

Advantageously the key-holder may also function as a latch that prevents the operational extended leg from being raised! retracted until the key is correctly stored in the key-holder.

In a further aspect the present invention provides an interlock procedure for trailers, primarily articulated lorry trailers! HGV trailers, where the trailer hitches by a hitch coupling to a tractor unit that tows the trailer and the trailer has at least one landing leg to support the trailer front end when parked and decoupled from the tractor unit, the method protecting against inadvertent dropping of the trailer, the method comprising housing a signaling means (eg a key or switch) at the trailer that is only accessible or activated when the leg is extended so that it may only then operate! be used to indicate for or directly deactivate/unlock the hitch coupling release constraint means on the tractor unit/trailer release mechanism.

In a preferred embodiment of the system and method, movement of the trailer leg to the operative extended state may cause a device to control the movement of the trailer safety release mechanism -moving the hitch coupling release constraint means to a released state. The device to control the movement of the trailer safety release mechanism may comprise a piston that operates a latch of the hitch coupling release constraint means or a Bowden cable, a chain linkage or a system of links and levers which actuates a latch of the hitch coupling release constraint means.

In an alternative embodiment the signalling means may comprise a proximity switch, load sensor, micro switch or other electrical switch at the leg configured to sense if the leg is extended or load bearing and to accordingly complete a circuit that: a) activates a visual or audible indicator showing that it is safe to open!deactivate the hitch coupling release constraint means; and/ or b) directly operates a solenoid operated latch to open/deactivate the hitch coupling release constraint means, to allow release of the trailer. Suitably the system comprises an electrical circuit between the tractor unit and the trailer and which may be part of or run parallel to the electrical wiring that runs between the tractor unit and trailer for operating lights or other electrical devices of the trailer. In particular the multi-pin electrical coupling between the two may be used to transmit the electrical signal from the signalling means to the warning device in the tractor unit cab or directly to the hitch coupling release constraint means on the tractor unit.

In one aspect the signalling means comprises an electrical switch that comprises a load sensor and the system is configured so that when the cab reconnects to the trailer and the load is taken by the tractor unit the load sensor on the trailer will detect that the leg is no longer load bearing and cause the hitch coupling release constraint means to close! activate to prevent release of the trailer.

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In another aspect the signalling means comprises a sensor at the leg and a light or other visual or audible indicator mounted on the trailer or tractor unit so that when the leg is extended or load bearing an indication is given that shows it is safe to release the cab/trailer coupling locking mechanism.

The system can also be applied to other types of trailer equipped with retracting parking legs and in which the tow coupling is secured with a lock mechanism.

Brief Description of the Drawings

A first preferred embodiment of the invention will now be more particularly described, solely by way of example, with reference to the accompanying drawings in which: Figure 1 is a perspective view of a telescopic support leg of a trailer that has been modified in accordance with the first preferred embodiment of the present invention, the lower section of the leg being in raised! retracted state as it is for travel; Figure 2 is a corresponding view of the telescopic support leg with the lower section of the leg being in its lowered/ extended state as during use for support of the parked trailer and showing an exposed opening of a key-holding chamber; Figure 3 is an exploded assembly view of the key-holder that sits pivotally mounted in the chamber of the lower leg section; Figure 4 is a view of the key-holder assembled, with key in place, and in its stowed upright state; Figure 5 is a view of the lower leg section opening of the key-holding chamber showing the key-holder stowed; Figure 6 is a corresponding view of the lower leg section opening showing the key-holder projecting out from the opening for access to the key and at the same time providing an end stop shoulder to prevent the extended leg from being retracted until the key is correctly placed back into it subsequently.

Figure 7 is a view of the male and female members of the hitch coupling engaged together and with the padlock mounted in place behind the male member in the aperture of the hitch coupling that would normally receive a safety clip as confirmatory release constraint; Figure 8 is a view of the prior art arrangement of male and female members of the hitch coupling engaged together and showing the conventional use of the safety clip as confirmatory release constraint; Figure 9 is a view of the bed of a tractor unit showing the fifth wheel I where the release handle / constraint means of the hitch coupling is generally located; and Figure 10 is a perspective view of a telescopic support leg of a trailer that has been modified in accordance with a variant of the first preferred embodiment of the present invention in which the key-holder is housed in an external attachment to the telescopic support leg rather than within the leg.

Description of the Preferred Embodiment

Referring to the Figures, the first preferred embodiment of the system is an effective but low cost system that comprises a modified telescopic landing leg of a trailer where the landing leg is adapted to house a key 7a. The key 7a is for a key operated padlock 10 that is used as the hitch coupling release constraint on the tractor unit. This padlock ba (see Figure 7) is fitted to the tractor unit's hitching point at an existing safety clip aperture of the hitch coupling in the place of the safety clip 100 (see Figure 8) that conventionally serves as the hitch coupling release constraint.

Referring to Figure 7, the hoop locking member ba of the padlock 10 replaces the conventional safety clip 100. It extends through the aperture 11 that the safety clip would normally extend through on the truck unit's hitch coupling structure to secondarily! confirmatorily constrain the engaged kingpin of the trailer in the socket of the fifth wheel 110 on the truck unit. It does so by constraining the coupling release handle liSa, bin the locked state holding the kingpin in place. The release handle 115a, b comprises a handle ring 115b to be pulled by the driver and a handle bar/lever 11 5a extending from the handle ring 11 5b into a side opening 13 of the body of the fifth wheel 110 and at its inner end constraining release of the kingpin from the socket of the hitch coupling.

The key operated lock 10 is particularly preferably of a type that has key retention so that when the lock 10 is closed the key can be removed but is retained when the lock is open.

The modified telescopic landing leg shown in Figures 1 and 2 comprises an upper leg section 1 and lower leg section 2 where extending the lower leg out from within the upper leg section 1 reveals an aperture 3.

A key-holder! latch mechanism is installed within the lower leg section 2 adjacent to the aperture 3. The mechanism comprises a housing cartridge 4 holding within it a pivotal latch 6 which is pivotally mounted to the housing cartridge 4 by pivot pin 6.

The latch 6 functions both as a latch and as a key holder. It has a socket into 7b into which the key 7a is inserted and the latch 6 also has a clip 8 that the stem of the key 7a engages with when the latch 6 is closed.

When the latch 6 is closed! retracted, the latch 6 is aligned with the axis of the leg 1, 2 and the latch 6 containing the key 7a is thus wholly within the space envelope of the lower leg section 2. When the leg 1, 2 is lowered to its extended operative load-bearing state, the aperture 3 is revealed and the latch 6 tips or may be pulled outwardly from the chamber! housing cartridge 4 to project from the aperture 3 and thus becomes accessible. This reveals the key 7a so that the key 7a can be withdrawn by the driver to open the padlock 10 on the hitch coupling of the tractor unit to then be able to uncouple the trailer from the tractor unit to be able to drive away leaving the parked trailer behind.

When the trailer needs to be towed, the leg 1, 2 needs to be retracted and the latch 6 prevents this because it will not enter the upper leg section 2 while it is exposed! extended through the aperture 3. The key 7a needs to be fully inserted in its socket 7b in the latch 6 and the latch 6 pushed back in so that the clip 8 engages with the

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key 7a stem, thereby holding the latch 6 retracted and the leg 1, 2 can then be raised. The key holding latch 6 thus prevents a driver from lifting the landing leg 1, 2 to tow the trailer away until he has properly re-inserted the key ready for next time the trailer is parked up.

Furthermore, when the driver returns to tow the trailer away he can be substantially assured of proper engagement of the hitch coupling. Since the key 7a can only be removed from the key-retentive padlock 10 on the hitch coupling and transferred to the landing leg 1, 2 to raise the landing leg when the padlock 10 is closed and the padlock 10 can only be closed in the safety clip aperture 11 when the hitch coupling is properly engaged, the proper engagement of the hitch coupling before retracting the landing legs is substantially ensured.

In a variant of the first preferred embodiment that is illustrated in Figure 10, the housing for the key 7a on the landing leg 1, 2 may be provided not within the leg 1, 2 but as an external housing attachment 14, 15 that is fixed, e.g. welded or bolted, onto the landing leg 1, 2. This external housing attachment 14, 15 comprises an upper housing section 14 that telescopes relative to a lower housing section 15 with the upper housing section 14 fixed to the upper landing leg section 1 and the lower housing section 15 fixed to the lower landing leg section 2. Thus the external housing attachment upper and lower sections 14, 15 telescopically move relative to each other with the telescopic movement of the landing leg sections 1, 2. The external housing attachment 14, 15 performs in exactly the same way as the original variant of Figures 1 to 6, with the key 7a being received in a compartment in the external housing attachment 14, 15. The key-holder! latch mechanism is installed through an aperture in the housing attachment lower section 15 in a housing cartridge 4 there rather than in the lower section 2 of the landing leg. A primary reason for adopting this external housing variant rather than the internal variant of Figures 1 to 6 is to be able to retro-fit the apparatus to a trailer's landing leg 1, 2 without any compromise at all to the structural integrity of the landing leg 1, 2. This variant is simply an add-on feature and does not require any aperture to be made in the landing leg itself.

This first preferred embodiment of the system including the variant described above can be carried out as a retrofit to existing trailers at low cost and provides a simple, effective and low cost system that addresses the major problem of inadvertent trailer dropping and ensures that the key is re-housed in the leg for re-use later.

In a more refined embodiment of the interlock system the system may be configured so that movement of the trailer leg to the operative extended state causes a device to control the movement of the trailer safety release mechanism -moving the hitch coupling release constraint means (the hitch coupling release constraint means being either the main latch of the hitch coupling that couples the tractor unit and trailer or a confirmatory! auxiliary latch or pin like the confirmatory safety clip) to a release state to allow release of the trailer. This may be effected by a piston that via a pneumatic or hydraulic circuit operates a latch of the hitch coupling release constraint means. Alternatively this may be effected by a Bowden cable, a chain linkage or other system of links! levers which actuate the latch of the hitch coupling release constraint means.

In a yet further alternative embodiment the interlock system may use an electrical circuit between the tractor unit and the trailer. This may involve a signalling arrangement which may, for example, comprise a proximity switch, load sensor, micro switch or other electrical switch at the leg configured to sense if the leg is extended or load bearing and to accordingly complete a circuit that: a) activates a visual or audible indicator showing that it is safe to open/deactivate the hitch coupling release constraint means; and! or b) directly operates a solenoid operated latch to open/deactivate the hitch coupling release constraint means, to allow release of the trailer. For example, where the electrical switch comprises a load sensor the system is configured so that when the cab reconnects to the trailer and the load is taken by the tractor unit the load sensor on the trailer will detect that the leg is no longer load bearing and the solenoid latch will cause the hitch coupling release constraint means to close! activate to prevent release of the trailer.

In a more passive arrangement of the system the signalling device may comprise a sensor at the leg and a light or other visual or audible indicator mounted on the trailer or tractor unit so that when the leg is extended (or load bearing) an indication is given that shows it is safe for the driver to manually release the cab/trailer coupling locking mechanism. Additionally the system can be arranged to warn the driver that it is unsafe to drive off if the driver thinks he has coupled the unsupported trailer when he has not done so, by incorporating in the system a sensor configured to alert if the hitch coupling is not fully engaged or the hitch coupling release constraint is not properly in place when the landing leg is retracted.

Claims

Claims 1. An interlock system for trailers, primarily articulated lorry trailers I HGV trailers, where the trailer hitches by a hitch coupling to a tractor unit that tows the trailer and the trailer has at least one landing leg to support the trailer front end when parked and decoupled from the tractor unit, the system protecting against inadvertent dropping of the trailer, the system comprising: a signaling means that indicates the operational state of the trailer landing leg and whereby the system, responsive to the state of the trailer landing leg, constrains the release of the hitch coupling between the tractor unit and trailer preventing inadvertent release of the trailer if the trailer landing leg is not extended to its operative state.
2. An interlock system as claimed in claim 1, in which the signaling means is mounted in or on the landing leg.
3. An interlock system as claimed in claim 1 or 2, in which the signaling means comprises a key-holder holding a release key to release a lock on the hitch coupling, the key-holder being configured for the key to be substantially only accessible when the trailer landing leg is extended to its operative state.
4. An interlock system as claimed in claim 2 and 3, in which the key-holder is mounted within a chamber in a part of the trailer leg.
5. An interlock system as claimed in claim 2 and 3, in which the key-holder is mounted within an external chamber on a part of the trailer leg.
6. An interlock system as claimed in claim 3, 4 or 5, in which the key-holder or a linked component functions as a latch that prevents the operational extended leg from being raised! retracted until the key is correctly stored in the key-holder.
7. An interlock system as claimed in claim 3, 4, 5 or 6, in which the system comprises a key operated lock for locking the engaged hitch coupling in place.
8. An interlock system as claimed in claim 7, in which the key operated lock is used as a constraint for locking the engaged hitch coupling in place.
9. An interlock system as claimed in claim 8, in which the key operated lock is used in place of a safety clip, with a locking member of the key operated lock extending through a safety clip aperture in a hitch coupling structure of the truck unit.
10. An interlock system as claimed in claim 7, 8 or 9, in which the key operated lock is of a type that has key retention so that when the lock is closed the key can be removed but is retained when the lock is open.
11. An interlock procedure for trailers, where the trailer hitches by a hitch coupling to a tractor unit that tows the trailer and the trailer has at least one landing leg to support the trailer front end when parked and decoupled from the tractor unit, the method protecting against inadvertent dropping of the trailer, the method comprising housing a signaling means (eg a key or switch) at the trailer that is only accessible or activated when the leg is extended so that it may only then operate! be used to indicate for or directly deactivate/unlock a hitch coupling or hitch coupling release constraint means on the tractor unit/trailer hitch coupling.
12. An interlock system as claimed in claim 1, in which movement of the trailer leg to the operative extended state causes a device to control the movement of the trailer safety release mechanism to move the hitch coupling release constraint means to a released state.
13. An interlock system as claimed in claim 12, wherein the device to control the movement of the trailer safety release mechanism comprises a piston that operates a latch of the hitch coupling or hitch coupling release constraint means.
14. An interlock system as claimed in claim 12, wherein the device to control the movement of the trailer safety release mechanism comprises a Bowden cable, a chain linkage or a system of links and levers which actuates a latch of the hitch coupling or hitch coupling release constraint means.
15. An interlock system as claimed in claim 1 or 12, wherein the signalling means comprises a proximity switch, load sensor, micro switch or other electrical switch configured to sense if the leg is extended or load bearing and to accordingly complete a circuit that: a) activates a visual or audible indicator showing that it is safe to open/deactivate the hitch coupling release constraint means; and/ or b) directly operates a solenoid operated latch to open/deactivate the hitch coupling or hitch coupling release constraint means, to allow release of the trailer.
16. An interlock system as claimed in claim 15, wherein the system comprises an electrical circuit between the tractor unit and the trailer.
17. An interlock system as claimed in claim 15 or 16, wherein the electrical switch comprises a load sensor and the system is configured so that when the cab reconnects to the trailer and the load is taken by the tractor unit the load sensor on the trailer will detect that the leg is no longer load bearing and the solenoid latch will cause the hitch coupling release constraint means to close/ activate to prevent release of the trailer.
18. An interlock system as claimed in claim 15, wherein the signalling means comprises a sensor at the leg and a light or other visual or audible indicator mounted on the trailer or tractor unit so that when the leg is extended or load bearing an indication is given that shows it is safe to release the cab/trailer coupling locking mechanism.
19. An interlock system as claimed in any of claims 15 to 18, wherein the system comprises a sensor configured to trigger an alert if the hitch coupling release constraint is not properly in place when the signalling means indicates that the landing leg is retracted.
20. An interlock system for trailers, where the trailer hitches by a hitch coupling to a tractor unit that tows the trailer and the trailer has at least one landing leg to support the trailer front end when parked and decoupled from the tractor unit, the system being substantially as hereinbefore described with reference to the accompanying drawings.