GB2403278A

GB2403278A - Auxiliary trailer braking system

Info

Publication number: GB2403278A
Application number: GB0314640A
Authority: GB
Inventors: Roy Stephen Nash
Original assignee: Individual
Current assignee: Individual
Priority date: 2003-06-24
Filing date: 2003-06-24
Publication date: 2004-12-29
Also published as: GB0314640D0

Abstract

An auxiliary actuator assembly for a trailer overrun braking system, the auxiliary actuator assembly comprising a remotely operable actuator having a link for attachment to a bake mechanism of a trailer overrun braking system, the remotely operable actuator being connectable for operation by a driver in a vehicle towing the trailer to apply braking to the trailer independently of the brakes of the towing vehicle to stabilize sway. The remotely operable actuator and link may comprise electromagnets and/or a winch drum and cable, which could be powered by an electric motor driven by a 12V supply, with connection controls provided for the driver.

Description

TRAILER BRAKING SYSTEM

The invention relates to braking systems for towed assemblies such as trailers, caravans and the like which utilise over-run braking. It particularly concerns prevention or reduction of sway.

Trailers and other towed assemblies, all termed generally herein as "trailers", over 750 kg in weight are required to have a braking system. Heavy trailers, i.e. over 3,500 kg have air brakes, but lighter trailers are provided with over-run braking that operates via a mechanical linkage in response to braking ofthe towing vehicle.

When a trailer is being towed, crosswinds, uneven road surface or camber or steering adjustments may cause the trailer to sway or snake from side to side. Continued or large amplitude sway is potentially dangerous and may even result in jack-knifing.

There are frictional arrangements that can be attached to or near the coupling head which provide some resistance at the coupling to onset of sway, but these have limited effectiveness especially with heavier trailers such as those which are carrying another vehicle.

The present invention is directed towards a system to stop swaying that can be incorporated into an over-run braking system.

According to the invention there is provided an auxiliary actuator assembly for a trailer over-run braking system, the auxiliary actuator assembly comprising a remotely operable actuator having a link for attachment to a brake operating mechanism of a trailer over-run braking system, the remotely operable actuator being connectable for operation by a driver in a vehicle towing the trailer to apply braking to the trailer independently of the brakes of the towing vehicle to stablise sway.

More generally the over-run braking mechanism has a sliding coupling that operates a lever at the onset of braking. An actuator rod is coupled to the lever which in turn operates brake cables. The auxiliary actuator assembly allows the braking mechanism - 2 to be actuated independently of the towing vehicle brakes. Actuation is electrical, either via a motor or electromagnet and moves one of the elements in the mechanism, such as the lever, rod or brake cable.

The invention is now described by way of example with reference to the accompanying drawing which shows a schematic representation of a preferred embodiment ofthe invention.

When a vehicle that is towing a trailer brakes, if there are no brakes on the trailer its momentum causes it to push towards the towing vehicle. In over-run braking the onset of this push is used to activate brakes on the trailer via a mechanical linkage.

Figure 1 shows a typical over-run braking linkage also incorporating an additional anti-sway actuator in accordance with a preferred embodiment of the invention.

Referring now to the drawing, part of a coupling for the trailer is shown in which a coupling head 1 will engage with a tow ball 2 on the towing vehicle. Other couplings, such as a pin, may be used. Rearward of the coupling head is a tow coupling 3 which includes a sliding coupling 4. The details of the sliding coupling are not part of the invention and any suitable form may be used. The sliding coupling provides a degree of longitudinal sliding shown by arrow 5. When the towing vehicle brakes, the trailer pushes on the outer part of the tow coupling 3 which slides over an inner part 6 of the coupling in the leftward direction as viewed. A pivoted over-run lever 7 then impinges on the end of the inner part 6 and moves rightwards as shown by arrow 9, thereby operating an activating rod 10 that applies the trailer brakes, usually via connection to brake cables.

Damping and other smoothing mechanisms may also be included.

The present invention proposes providing an auxiliary mechanism for activating the brakes, in particular so that braking can be applied to the trailer brakes to stablise sway without applying the brakes of the towing vehicle. This additional mechanism links in - 3 to the over-run brake operating mechanism. In the embodiment shown in Figure 1 it has a mechanical link to the activating rod 10 and an independent actuator that moves the actuator rod 10 in the direction to cause braking and releases it to remove braking.

S A suitable form of auxiliary link is shown in the drawing and comprises an electrically powered winch 11 that is mounted on the chassis of the trailer. A flexible winch cable 12 is attached to the activating rod 10 by a clamp 14. Power cables 13 can be connected to a 12 volt supply and power control operated from the driving position of the towing vehicle.

It will be appreciated that forms of actuator other than a winch, such as a piston and cylinder arrangement, or other form of mechanical linkage could be used instead.

The actuator is driven by an electrical motor which, for example, rotates the winch or drives a piston. The arrangement may provide drive to move the actuator to apply brakes and have either reverse drive to remove the brake or some other restoring force or bias to remove the brake.

The arrangement is shown with the cable 12 attached to the activating rod 12.

However, the actuator linkage could be made to the brake cable, in a similar way to the attachment of the rod 12 to the brake cable. Alternatively the actuator could be connected to move the over-run lever 7 (in the direction of arrow 9).

A non-mechanical linkage may be provided, such as using an electromagnetic instead of a motorised mechanical link. This may be particularly convenient for moving the lever 7. - 4

Claims

1. An auxiliary actuator assembly for a trailer over-run braking system, the auxiliary actuator assembly comprising a remotely operable actuator (11) having a link (12) for attachment to a brake operating mechanism of a trailer over-run braking system, the remotely operable actuator being connectable for operation by a driver in a vehicle towing the trailer to apply braking to the trailer independently of the brakes of the towing vehicle to stablise sway.

2 An assembly according to claim 1 in which the list is attached to an activation rod (10) of the over-run braking system.

3. An assembly according to claim 1 in which the link is attached to a pivoted lever (7) in the over-run braking system.

4. An assembly according to claim 1 in which the link is attached to a brake cable.

5. An assembly according to any preceding claim in which the link includes an electromagnet.

6 An assembly according to any of claims 1 to 4 in which the remotely operable actuator and link comprise a winch drum and winch cable.

7. An assembly according to any of claims 1 to 4 or claim 6 in which the remotely operable actuator includes an electrically powered motor.

8. An assembly according to claim 7 in which the motor is driven by a 12volt supply with connection controls for the driver.