GB2262969A - Braking apparatus for towed vehicles - Google Patents

Abstract

The brakes of a towed vehicle 24 are actuated together with the brakes of the towing vehicle 26 by means of a pneumatic piston and cylinder arrangement 18 mounted in the cab of the towed vehicle 24 and operable to depress the brake pedal 14 of the towed vehicle. The piston and cylinder 18 may be actuated by the control air of the towing vehicle 26, which also serves to control operation of the brakes of the towing vehicle 26, the control air being progressively supplied to the piston and cylinder 18 in response to movement of the brake pedal 15 of the towing vehicle. The piston and cylinder 18 may be clamped, by means of an adjustable mounting bracket (22, Figs 1 and 3), to the steering column or to an extensible pillar (20). <IMAGE>

Description

BRAKING APPARATUS FOR TOWED VEHICLES This invention relates to braking apparatus for towed vehicles, and in particular to brake operating apparatus for activating the brakes of a casualty vehicle being towed by another vehicle.

In most circumstances, the braking for a vehicle train comprising a broken down casualty vehicle and a towing vehicle is provided solely by the towing vehicle.

When the casualty vehicle is a heavy truck or lorry, this may result in dangerous overloading of the braking system of the towing vehicle. Various means have been adopted in an effort to provide greater braking capability for such vehicle trains. One such method is to have an operator sit in the cab of the casualty vehicle and apply the brakes of the casualty vehicle when the brake lights of the towing vehicle are illuminated due to the operator of the towing vehicle applying the brakes. This is of course only suitable where the casualty vehicle is being flat-towed from the front and the brake lights are visible to a person in the cab of the casualty vehicle.Further, the reaction time of the casualty vehicle operator may lead to a significant lag between the application of the brakes of the casualty vehicle and the towing vehicle, and it is very difficult to provide equal braking force for both the vehicles in such circumstances, making control of the vehicle train more difficult.

In some circumstances operators have also been known to connect the brake system control air of the pneumatic braking system of the towing vehicle to the control air of the casualty vehicle. In the majority of heavy trucks, a control air system is used to control a stored air supply; the stored air provides the braking force while the control air controls the level of braking. Many vehicles are provided with an external coupling for the stored air system, but are not provided with such a coupling for the control air system, such that to access the control air system the creation of a separate coupling is required.

In many jurisdictions such interference with the control air system is illegal and is in any event a relatively difficult procedure and may interfere with the proper operation of the vehicle braking system.

It is an object of the present invention to obviate or mitigate these disadvantages by providing apparatus which links the braking system of the towing vehicle with an actuator that acts directly on the brake pedal of the casualty vehicle.

According to one aspect of the present invention there is provided brake operating apparatus for activating the brakes of a casualty vehicle being towed by another vehicle, the apparatus comprising a brake pedal actuator for mounting in the cab of the casualty vehicle and actuating means for operating the brake pedal actuator to depress the brake pedal of the casualty vehicle and apply the brakes thereof in response to the brakes of the towing vehicle being applied.

Conveniently, the actuator is operated by means of the control air of the towing vehicle, which also serves to control operation of the brakes of the towing vehicle, the control air being progressively supplied to the brake pedal actuator in response to movement of the brake pedal of the towing vehicle.

The brake pedal actuator may be in the form of a pneumatic piston and cylinder arrangement. The actuator may be clamped to the steering column of the casualty vehicle or may be provided with other mounting means where such mounting is not possible or convenient.

Braking a casualty vehicle utilising the apparatus will normally provide a level of braking force sufficient to safely slow or stop the vehicle train and provides significantly greater braking capability than is available using only the braking system of the towing vehicle, Operating the braking system of the casualty vehicle via the brake pedal allows the apparatus to be easily installed without interference with the existing braking system, and the braking obtained benefits from the controls and safety features of the existing braking system.

This and other aspects of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a side view of brake operating apparatus, in accordance with a preferred embodiment of the present invention, fitted in the cab of a casualty vehicle; Figure 2 is a schematic diagram of a towing vehicle and a casualty vehicle incorporating the brake operating apparatus of Figure 1; and Figure 3 is a perspective view of a mounting bracket of the brake operating apparatus of Figure 1.

Reference is first made to Figure 1 of the drawings which illustrates brake operating apparatus in accordance with a preferred embodiment of the present invention, for use in activating the brakes of a casualty vehicle. The Figure shows a cab of a casualty vehicle with steering wheel 10, steering column 12, brake pedal 14 and driver's seat 16. The brake operating apparatus includes a brake pedal actuator in the form of a pneumatic piston and cylinder arrangement 18 which acts on the brake pedal 14.

The piston 18 is provided with a quick release valve 19 (Figure 2), as known the art, and a retracting spring (not shown). As will be described the piston 18 may be mounted to the steering column 12 where appropriate, or may be mounted, as shown in Figure 1, to a fitted mounting pillar 20 via an adjustable mounting bracket 22.

Before describing the elements of the apparatus in detail, reference is made to Figure 2 of the drawings which shows a schematic illustration of a casualty vehicle 24 and a towing vehicle 26 and includes an illustration of the braking systems of both vehicles. In this example both vehicles have brakes operated using similar pneumatic systems, each comprising a stored air system and a separate, control air system. In both vehicles the stored air system is represented by chain dotted lines and includes respective stored air reservoirs 28, 30 and lines 32, 34 leading through control valves 36, 38 to the brakes of the vehicles. Though not described herein, in addition to providing the braking power for the vehicle the stored air may also be used to operate many of the vehicle accessories. The supply of the stored air to operate the brakes is achieved by means of the control air supply, illustrated in the drawings by solid lines 40, 42. The control air lines are linked to the brake pedals 14, 15 of each vehicle and also to the respective control valves 36, 38. In normal operation, operation of the brake pedal of a vehicle results in control air adjusting the control valves 36, 38 to allow stored air to activate the vehicle brakes. Those skilled in the art will realise that this is of course a substantially simplified description of what are normally very sophisticated systems, and the drawing does not include details of any compressors, control valves and the like, the provision of which will be obvious to those of skill in the art.

The towing vehicle 26 is provided with coupling points 50, 52 for attaching flexible lines 54, 56. One of these lines 54 may be connected directly to the stored air reservoir 28 of the casualty vehicle. The control air line 56 is connected to the piston 18, as will now be described in more detail.

Reference is now also made to Figures 1 and 3 of the drawings, Figure 1 showing the piston 18 mounted on a pillar 20 fixed in the cab of the casualty vehicle 24.

The pillar 20 provides a secure mounting for the piston 18 at a suitable location relative to the brake pedal 14 to allow the piston 18 to depress the pedal 14 when extended. The piston 18 is fixed to the pillar 20 using a mounting bracket 22 which is shown in greater detail in Figure 3. The bracket 22 comprises a rectangular mounting plate 60 on one side of which is mounted a piston mounting plate 62 and on the other side of which are mounted two spaced semi-circular plates 64, 66 to provide mountings for radius arms 68, 70 (only one shown in Figure 3) used to secure the bracket 22 to the pillar 20. The piston mounting plate 62 is apertured at 72 to receive fastening devices to secure the piston 18 to the plate 62 and has a tubular rod 74 welded to one edge.U-clamps 76, 78 pass around the rod 74 through respective apertures in the plate 62 and may be tightened to the mounting plate 60 to fix the plate 62 and piston 18 in a desired angular rotation relative to the mounting plate 60. The plate 62 is generally disposed at right angles to the mounting plate 60, but may be adjusted around 200 above or below the horizontal plane if necessary.

The semi-circular plates 64, 66 are fixed to the mounting plate and extend perpendicularly therefrom. Each plate 64, 66 is provided with a slot 80 which receives the shank of a set screw 82 which passes through an inner end of the radius arm 68 and engages a nut welded on the other side of the arm. The screw 82 may be tightened to clamp the arm 68 at the desired position on the plate 64. The free end of the arms provided with a U-bolt 84 for extending around the pillar 20, and a saddle 86 is provided to secure the U-bolt 84 to the pillar 20.

The mounting bracket 22 may be used to mount the piston 18 on the steering column of the vehicle, though in many cases access to the column will be obstructed, requiring the use of the pillar 20. As may be seen in Figure 1, the pillar extends between the cab floor 88 and the steering wheel 10 and is length adjustable; a lower tubular portion 90 receives an upper threaded portion 92 which engages a knurled nut 94 mounted bearing against the upper end of the tubular portion 90. A pinned foot 96 is fitted to the lower end of the tubular portion 90 and the upper end of the threaded portion 92 is provided with a saddle 98. Thus, by adjusting the nut 94 an operator may tightly engage the pillar between the cab floor 88 and the steering wheel 10.The pillar 20 is additionally held in place by means of a strap 100 which extends from a ratchet winder 102 mounted on one side of the tubular portion 90, though slots on each side of the saddle 86 and down the other side of the tubular portion 90 to an eyelet 104, with the free end of the strap 100 being provided with a hook for securing to the mounting frame of the drivers seat 16. The strap 100 is passed over the steering wheel to hold a portion of the steering wheel firmly within the saddle 98 and is tightened using the ratchet winder 102.

In use, the operator of the towing vehicle 26 mounts the piston 18 in the casualty vehicle 24 with the end of the piston 18 resting lightly on the brake pedal 14 of the casualty vehicle 24. The piston 18 is then connected to the control air coupling 52 of the towing vehicle, and the stored air system of the casualty vehicle connected to the stored air system of the towing vehicle 26. The casualty vehicle 24 may then be suitably secured to the towing vehicle 26 and transported from the breakdown location.

When the operator of the towing vehicle applies the brakes the control air system of the towing vehicle operates the brakes of the towing vehicle while simultaneously extending the piston 18 to apply the brakes of the casualty vehicle 24. When the brakes of the towing vehicle are released, the quick release valve on the piston 18 exhausts air from the piston, allowing the brakes of the casualty vehicle to be released immediately.

This arrangement allows both sets of brakes to be applied almost simultaneously and takes full advantage of the control and safety systems of the braking system of the casualty vehicle such as anti-locking sensors, load sensors and the like. Also, the apparatus can be relatively quickly and easily fitted to the casualty vehicle and does not require any modification to the braking system of the casualty vehicle.

It will be clear to those of skill in the art that the above described example is merely exemplary of the present invention. The description relates to both a towing vehicle and casualty vehicle provided with pneumatic braking systems, though the system could equally operate using braking systems actuated using different fluids, a combination of fluids, or even using electrical controls.

Claims (15)

1. Brake operating apparatus for activating the brakes of a casualty vehicle being towed by another vehicle, the apparatus comprising a brake pedal actuator for mounting in the cab of the casualty vehicle and operable to depress the brake pedal of the casualty vehicle and apply the brakes thereof in response a signal indicative of the brakes of the towing vehicle being applied.

2. The apparatus of claim 1 in which the actuator is operated by the control air of the towing vehicle, which also serves to control operation of the brakes of the towing vehicle, the control air being progressively supplied to the brake pedal actuator in response to movement of the brake pedal of the towing vehicle.

3. The apparatus of claim 1 or 2 in which the brake pedal actuator is in the form of a fluid actuated piston and cylinder arrangement.

4. The apparatus of claim 3 in which the piston and cylinder arrangement is provided with a quick release valve to exhaust fluid from the piston on the brakes of the towing vehicle being released.

5. The apparatus of claim 3 or 4 in which the piston and cylinder arrangement is provided with a retracting spring.

6. The apparatus of any one of claims 1 to 5 in which the actuator is clamped to the steering column of the casualty vehicle.

7. The apparatus of any one of claims 1 to 5 further comprising a mounting member for location in the cab of the casualty vehicle and for providing a mounting for the brake pedal actuator.

8. The actuator of claim 7 in which the mounting member is in the form of an adjustable length mounting pillar adapted to be located between the steering wheel and the cab floor of the casualty vehicle.

9. The actuator of claim 8 in which the mounting member is provided with a floor-engaging pinned foot at a lower end thereof and steering wheel engaging saddle at an upper end thereof.

10. The actuator of claim 9 further comprising a strap for extending over the saddle to hold a portion of the steering wheel in the saddle and the free end of the strap being attachable to the frame of a seat in the cab of the casualty vehicle.

11. The actuator of claim 10 in which a ratchet winder is mounted on the mounting pillar for tightening the strap.

12. The actuator of any one of claims 6 to 11 further comprising an adjustable mounting bracket for mounting the brake pedal actuator on the steering column or mounting member.

13. The apparatus of claim 2 or any one of claims 3 to 12 when dependent on claim 2 in combination with a towing vehicle provided with a controlled air coupling point for attachment of a fluid line for connection to the brake pedal actuator.

14. The apparatus and towing vehicle of claim 13 in which the towing vehicle is provided with a stored air coupling point for attachment of 9 fluid line for connection to the stored air reservoir of the casualty vehicle.

15. Brake operating apparatus substantially as described herein and as illustrated in the accompanying drawings.