GB2360561A

GB2360561A - Vehicle tractor and trailer having a coupling disk brake

Info

Publication number: GB2360561A
Application number: GB0107292A
Authority: GB
Inventors: Martin John Scarr
Original assignee: Individual
Current assignee: Individual
Priority date: 2000-03-23
Filing date: 2001-03-23
Publication date: 2001-09-26
Anticipated expiration: 2021-03-23
Also published as: GB0007047D0; GB0107292D0; GB2360561B

Abstract

To stabilise a vehicle comprising a tractor and trailer, a brake disc hub 10 is mounted via a horizontal pivot 6 in a location between suitably strengthened chassis members 4 of the tractor in close proximity to a coupling point. The disc is acted upon by a brake caliper 17, an electromagnet or the like. A locking bar 26 has a cam lobe 28 which acts on a spring-loaded bolt 30. Flexibility is provided by a sprung damped parallelogram arrangement 32 or pivot assembly. The device may be controlled by a microprocessor based on relative motion between the sensing steering and coupling, and also control cadence or ABS braking of the wheels. The disc may be ovoid shape.

Description

k 2360561,VEHICLE STABILISING DE V7CE This invention relates to a

stabilising device, and more particularly to such a device for use in connection with or on an articulated heavy goods vehicle.

An articulated heavy goods vehicle is inherently unstable, particularly but not exclusively in heavy and/or emergency braking situations, and in the execution of some difficult manouevres. Hazardous situations still arise, despite recent technical and engineering advances, where the lighter trailer may swing out at a dangerous angle, the coupling point acting as the fulcrum. Or, the heavier trailer may push the lead vehicle or tractor unit to such an angle that driver control is lost, and in this case the front wheels of the lead vehicle or tractor unit act as the fulcrum with the coupling point exerting the leverage. In each instance, the trailer is travelling faster and has a greater momentum than the lead vehicle or tractor unit.

Smooth controlled braking calls for sensitivity and a tremendous variation in technique. The driver has to be aware of the weather and the road surface conditions. The basic requirement of any braking system is that it should slow or stop the vehicle smoothly and under control. This means two things: firstly that the vehicle itself should have a system capable of doing this, and secondly the driver should have the skill to make best use of the system. Good, safe braking takes sensitive use of the controls as well as observing the changing road scene and anticipation of a potential need to brake.

Usually, the more braking force applied, the quicker the vehicle will stop, but a heavier vehicle takes more stopping in accordance with Newton's Second Law of Motion - deceleration f/g equals the braking force (F) applied divided by the weight M of the vehicle.

f = F g M The limit of adhesion depends upon the constant factor known as the coefficient of static friction. This indicates that a much greater force is needed to start a slide than to maintain it. A tyre begins to skid when F/M equals its coefficient of ffiction The present invention seeks to provide a device which will obviate the above and other disadvantages.

According to the present invention there is provided a vehicle stabilising device including a flexible mounted braking means located between chassis members of a lead vehicle or tractor unit, said brake means being located on or in close proximity to the vertical axis of the coupling point of said lead vehicle or tractor unit.

Preferably, said brake means will be a disc adapted to be acted upon by a suitably mounted brake, said brake being a ffiction caliper, electromagnet, or the like.

The device will preferably be controlled by an active micro-processor.

In order that the invention may be more readily understood, an embodiment thereof will now be described, by way of example only, reference being made to the accompanying drawings, wherein: Figure 1 is a cross-sectional plan view of part of a lead vehicle or tractor unit; Figure 2 is a side elevation on Figure 1; and Figure 3 is a cross- sectional rear elevation of part of a chassis of a trailer for use with the lead vehicle or tractor unit of Figures 1 and 2.

Referring to the drawings, and firstly to Figures 1 and 2, part of a lead vehicle or tractor unit - indicated generally by reference numeral 2 includes a chassis 4 which is suitably strengthened in the area of the mounting pivot 6 of the coupling brake discs, not shown. This is achieved by increas Mig the thickness of the chassis in this area, as indicated by reference numeral 8.

The pivot 6 locates through a disc hub 10 in a horizontal plane and perpendicular to the lead vehicle or tractor unit 2, thus providing sufficient clearance 12 with a caliper assembly 17 at even the most turning angles. This is necessary in order to accommodate variations of the road surface.

The disc itself may be circular if mounted on the same vertical axis as the pivot 6, or it may need to be a geometrically calculated ovoid shape if mounted on a different vertical axis.

The recesses to accommodate the locking bar - to be referred to later are indicated at 14. the recesses holding the locking bar Mi position during hitching and unhitching of the trailer, and when the device is not in use.

A splash guard 16 is provided to prevent contamination of the friction material of the device.

6 - Referring now to Figure 3, which shows part of a chassis of a trailer adapted for use with the lead vehicle or tractor unit of Figures 1 and 2, the trailer is indicated generally by reference numeral 18 and the chassis by reference numeral 20. Again, the chassis 20 is suitably strengthened as shown at 22 in the vicinity of the fixing points of a caliper assembly, not shown. A hinge 24 is provided to allow enough clearance to facilitate hitching and unhitching of the trailer to and from vehicle or tractor unit.

A locking bar 26 micorporates a 'push and twist' mechanism utilising a cam type lobe 28 acting on a spring-loaded bolt 30 in order to keep the assembly rigid when in use.

Between the above and the caliper there is provided means to achieve a degree of flexibility. Such means will comprise a sprung dampened parallelogram arrangement 32, and this arrangement, combined with the method of mounting of the discs, will ensure the efficient workig of the system even with the movement between the lead vehicle or tractor unit and the trailer caused by the variation in the road surface. 05 The upper caliper assembly may be moved into or out of its operational position by an electric powered motor, a servo unit or other suitable means, not shown.

In use, and in circumstances where the trailer is coupled to the lead vehicle or tractor unit and is travelling along a road, then when the vehicle brakes are applied, the device in accordance with the invention will be instantaneously armed by a switch assembly of the braking system. This would serve to activate sensors located on the road wheels, the steering column (now suitably calibrated) and the calibrated coupling brake assembly. Simultaneously, the data will be analysed and if necessary acted upon by an on-board microprocessor. Relative motion between the coupling and the steering colunm is detected, and in the event of this exceeding an acceptable value, i.e.

rotational movement of the coupling without corresponding movement of the steering column, this would indicate that the vehicle is becoming unstable. The microprocessor, via a suitable control system, would activate the application of the coupling brake caliper at sufficient force to counteract the rate of increase of rotational/longitudinal instability between the lead vehicle or tractor unit and its trailer, using a method similar to cadence braking or A. B. S.

When this situation develops, the lead vehicle or tractor unit usually may have less momentum than the trailer. This may be caused by one or more road wheels of the trailer skidding. The sensors so fitted would serve to pass this information to the microprocessor which would in turn activate a system to release the locked brakes of the trailer to the point of optimum braking efficiency. The brakes on the lead vehicle or tractor unit may also be released to a pomit probably beyond optimum efficiency. These actions, combined with the controlled release of the coupling brake, a point of equilibrium between the steering column and coupling having been achieved, would have a stretching and straightening effect on the vehicle as a whole, thus increasing the likelihood of the vehicle remaining stable and facilitating driver steering control.

In the event of the instability persisting as detected, then so do the counter-measures described, although obviously at a gradually decreasing magnitude. The manual engagement of the coupling brake this preferably having a degree of anti-rotational capability selected by the driver by means of an appropriate method of activation - would help to keep the lead vehicle or tractor unit and trailer reasonably rigid whilst driving or reversing on wet or slippery gradients or whilst negotiating hazardous road surface conditions.

The device would compliment the vehicle's existing differential lock, if so fitted.

A period of maximum application of the coupling brake would be incorporated into the system with a suitable failsafe option for the 05 driver, the system being self-monitoring for safety purposes.

Finally, an alternative to the parallelogram arrangement 32 may be a simpler pivot assembly, the vertical motion of the disc and caliper being accommodated instead by an allowance of perhaps plus or minus 10 10' rotation about locking bar 26.

Claims

CLAIMS:

1. A vehicle stabilising device including a flexible mounted braking means located between chassis members of a lead vehicle or tractor unit,, said braking means being located on or in close proximity to the vertical axis of a coupling point of said lead vehicle or tractor unit.

2. A vehicle stabilising device according to Claim 1, wherein said braking means is a disc adapted to be acted upon by a suitably mounted brake.

3. A vehicle stabilising device according to Claim 2, wherein the 15 bralde is a ffiction caliper, electromagnet, or the like.

4. A vehicle stabilising device according to any of Claims 1 to J',, wherein the device is controlled by an active microprocessor.

5. A stabilising device according to any of Claims 1 to 4, wherein said braking means is located on a mounting pivot, said mounting pivot locating through a disc hub in a horizontal plane and perpendicular to said lead vehicle or tractor unit.

6. A stabilising device according to Claim 5, wherein said disc hub is circular or of an ovoid shape, said shape depending on the axis on which said disc hub is mounted.

7. A stabilising device according to any of the preceding claims, wherein said stabilising device includes a locking bar mounted on a trailer adapted to be used in conjunction with the lead vehicle or tractor unit, said locking bar incorporating a push and twist mechanism utilising a cam type lobe acting on a spring-loaded bolt.

8. A stabilising device-according to Claim 7, wherein said locking bar is adapted to be located in recesses in the chassis members of said lead vehicle or tractor unit.

9. A stabilising device according to any of Claims 1 to 8, including a sprung dampened parallelogram arrangement so as to impart a degree of flexibility to said device.,

10. A vehicle stabilising device substantially as herein described with reference to and as illustrated in the accompanymig drawings.