GB2174160A

GB2174160A - Articulated vehicle braking system

Info

Publication number: GB2174160A
Application number: GB08605192A
Authority: GB
Inventors: John Smith
Original assignee: Individual
Current assignee: Individual
Priority date: 1985-03-02
Filing date: 1986-03-03
Publication date: 1986-10-29

Abstract

The system reduces the tendency of the articulated vehicle to jacknife upon wheel braking and comprises at least two brake portions, one on the trailer unit and one on the tractor unit, brought into contact when wheel braking is effected. As shown, a coupling comprises plates 18,20 attached to tractor and trailer units respectively-upper plate 20 is bolted to chassis of trailer unit and has brake lining material attached to it while plate 18 is hinged and is operable by hydraulic jacks 22 connected by pipelines 24 and connected to the wheel braking system. When that is operated, plate 18 contacts the lining to restrain pivoting about a vertical axis. Steel plates 18 or 20 may be replaced by a ring-lower plate or ring may be split into portions each operated by independent jack-lining material may be on lower plate. Air operated rams may be used with pneumatic brakes. <IMAGE>

Description

SPECIFICATION An anti-jacknifing device for articulated vehicles Articulated vehicles usually comprise a tractor unit and a trailer hinged together about a pivot point so that relative rotation can take place between the tractor and trailer when the vehicle is cornering or turning.

A common problem with such vehicles is that, under certain road conditions such as wet or slippery road surfaces, when the vehicle is braked excessive rotation or movement takes place between tractor and trailer.

This condition is known as jacknifing and has been the cause of numerous accidents many of them fatal.

The present invention seeks to provide a means of preventing this excessive and uncontrolled relative rotational movement between the tractor and trailer units of an articil- lated vehicle.

Accordingly the present invention provides an articulated vehicle braking system, the vehicle having a tractor unit and a trailer unit, the braking system including at least two brake portions, one of said portions being mounted on the tractor and the other one of said portions being mounted on the trailer, and brake operating means to move at least one of the brake portions into contact with the other brake portion to restrain relative rotational movement between the tractor and trailer, the said brake operating means being actuated upon operation of the vehide wheel braking system.

The tractor and trailer units are usually hitched together by a coupling arrangement which joins the units together but allows relative turning or rotation between the two units.

The vertical loading imposed by the trailer on the tractor is usually distributed by two substantially circular flat plates, one plate being on each unit. In one arrangement according to the invention at least part of the plate on the tractor unit is hinged and is provided with one or more jacks or rams which are either hydraulically or pneumatically operated depending upon the nature of the vehicle wheel braking system. The jacks or rams are all connected to the vehicle wheel braking system by a single T/Y junction connection or by a separate junction connection to each jack or ram.

The hinged portion of the plate on the tractor unit or the plate on the trailer unit is provided with a brake lining material and acts as a brake pad like the brake shoes or pads in conventional drum type or disc type vehicle brakes.

The hinged plate portion of the brake may be approximately semi-circular or could be made in a number of separate segments, each operated by an independednt jack or ram if required.

The brake lining material can for example be either a part annulus or horseshoe shaped in plan.

The present invention will now be more particularly described with reference to the accompanying drawings in which Figure 1 is a side elevation of an articulated vehicle showing the tractor unit and part of the trailer unit, Figure 2 is a plan view of the articulated vehicle shown in Fig. 1, Figure 3 is an enlarged view of part of the articulated vehicle shown in Fig. 1, and Figure 4 is an enlarged plan view of part of the articulated vehicle shown in Fig. 2.

Referring to the drawings, an articulated vehicle 10 comprises a tractor unit 12 and a trailer unit 14. The tractor and trailer units are hitched together by a coupling 16 which comprises two generally circular plates 18 and 20 attached to the tractor unit and trailer unit respectively. As shown in Figs. 2 and 4 the lower plate 18 has a portion cut away to receive a pivot (not shown) on the trailer unit.

The plate 20 is bolted to the chassis of the trailer unit and has brake lining material attached to it slightly below the top level of the tractor coupling in order to maintain a gap between the upper surface of the lining and underside of the trailer plate coupling.

The lower plate 18 is hinged about the centre line of the tractor coupling and is operated by three hydraulic jacks 22. The hydraulic jacks are all connected by pipelines 24 to a fourway junction 26 which itself is connected by a further pipeline 28 and a Y junction 30 to the vehicle braking system 32.

When the vehicle wheels are braked, whether the vehicle is cornering or travelling in a straight line, the hinged plate on the tractor unit contacts the brake lining on the plate on the trailer, so that pivoting about a verticle axis between the tractor and trailer units is constrained. Such constraint will reduce the tendency of an articulated vehicle to jacknife.

In further arrangements,-the steel plates 18 and 20 can be replaced in either case by a ring, brake lining material can be provided on the lower plate or ring as opposed to the plate on the trailer unit, or the lower plate or ring can be split into two or more portions each portion being operated by an independent jack.

In the case where a vehicle is provided with pneumatic brakes, the hydraulic jacks for the sake of convenience can be replaced by air operated rams.

A cover can be provided for the plate of the tractor unit so that the hinged plate or ring or portions of the plate or ring and the corresponding operated mechanisms can be protected from the weather.

1. An articulated vehicle braking system,

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION An anti-jacknifing device for articulated vehicles Articulated vehicles usually comprise a tractor unit and a trailer hinged together about a pivot point so that relative rotation can take place between the tractor and trailer when the vehicle is cornering or turning. A common problem with such vehicles is that, under certain road conditions such as wet or slippery road surfaces, when the vehicle is braked excessive rotation or movement takes place between tractor and trailer. This condition is known as jacknifing and has been the cause of numerous accidents many of them fatal. The present invention seeks to provide a means of preventing this excessive and uncontrolled relative rotational movement between the tractor and trailer units of an articil- lated vehicle. Accordingly the present invention provides an articulated vehicle braking system, the vehicle having a tractor unit and a trailer unit, the braking system including at least two brake portions, one of said portions being mounted on the tractor and the other one of said portions being mounted on the trailer, and brake operating means to move at least one of the brake portions into contact with the other brake portion to restrain relative rotational movement between the tractor and trailer, the said brake operating means being actuated upon operation of the vehide wheel braking system. The tractor and trailer units are usually hitched together by a coupling arrangement which joins the units together but allows relative turning or rotation between the two units. The vertical loading imposed by the trailer on the tractor is usually distributed by two substantially circular flat plates, one plate being on each unit. In one arrangement according to the invention at least part of the plate on the tractor unit is hinged and is provided with one or more jacks or rams which are either hydraulically or pneumatically operated depending upon the nature of the vehicle wheel braking system. The jacks or rams are all connected to the vehicle wheel braking system by a single T/Y junction connection or by a separate junction connection to each jack or ram. The hinged portion of the plate on the tractor unit or the plate on the trailer unit is provided with a brake lining material and acts as a brake pad like the brake shoes or pads in conventional drum type or disc type vehicle brakes. The hinged plate portion of the brake may be approximately semi-circular or could be made in a number of separate segments, each operated by an independednt jack or ram if required. The brake lining material can for example be either a part annulus or horseshoe shaped in plan. The present invention will now be more particularly described with reference to the accompanying drawings in which Figure 1 is a side elevation of an articulated vehicle showing the tractor unit and part of the trailer unit, Figure 2 is a plan view of the articulated vehicle shown in Fig. 1, Figure 3 is an enlarged view of part of the articulated vehicle shown in Fig. 1, and Figure 4 is an enlarged plan view of part of the articulated vehicle shown in Fig. 2. Referring to the drawings, an articulated vehicle 10 comprises a tractor unit 12 and a trailer unit 14. The tractor and trailer units are hitched together by a coupling 16 which comprises two generally circular plates 18 and 20 attached to the tractor unit and trailer unit respectively. As shown in Figs. 2 and 4 the lower plate 18 has a portion cut away to receive a pivot (not shown) on the trailer unit. The plate 20 is bolted to the chassis of the trailer unit and has brake lining material attached to it slightly below the top level of the tractor coupling in order to maintain a gap between the upper surface of the lining and underside of the trailer plate coupling. The lower plate 18 is hinged about the centre line of the tractor coupling and is operated by three hydraulic jacks 22. The hydraulic jacks are all connected by pipelines 24 to a fourway junction 26 which itself is connected by a further pipeline 28 and a Y junction 30 to the vehicle braking system 32. When the vehicle wheels are braked, whether the vehicle is cornering or travelling in a straight line, the hinged plate on the tractor unit contacts the brake lining on the plate on the trailer, so that pivoting about a verticle axis between the tractor and trailer units is constrained. Such constraint will reduce the tendency of an articulated vehicle to jacknife. In further arrangements,-the steel plates 18 and 20 can be replaced in either case by a ring, brake lining material can be provided on the lower plate or ring as opposed to the plate on the trailer unit, or the lower plate or ring can be split into two or more portions each portion being operated by an independent jack. In the case where a vehicle is provided with pneumatic brakes, the hydraulic jacks for the sake of convenience can be replaced by air operated rams. A cover can be provided for the plate of the tractor unit so that the hinged plate or ring or portions of the plate or ring and the corresponding operated mechanisms can be protected from the weather. CLAIMS

1. An articulated vehicle braking system, the vehicle having a tractor unit and a trailer unit, the braking system including at least two brake portions one of said portions being mounted on the tractor unit and the other one of said portions being mounted on the trailer unit, and brake operating means to move at least one of the brake portions into contact with the other brake portion to restrain relative rotational movement between the tractor and trailer units, the said operating system means being actuated upon operation of the vehicle wheel braking system.

2. A braking system according to claim 1 in which the tractor and trailer unit includes a coupling, the coupling comprising a support means attached to each of the tractor and trailer units, at least a portion of the support means on the tractor unit being movable by the brake operating means to bring said movable portion into contact with the other support means, a brake lining material being provided on at least one of the'support means.

3. A vehicle braking system according to claim 2 in which the brake lining material is provided on the support means attached to the trailer unit.

4. A vehicle braking system according to claim 2 or claim 3 in which the support means on the tractor unit is hinged about the centre line of the tractor coupling and is movable upon actuation of at least jacks connected to the vehicle braking system.

5. A vehicle system according to any one of the preceeding claims 2 to 4 in which the support means on the tractor unit is a ring and the support means of the trailer unit is a steel plate.

6. A tractor unit according to any one of the preceeding claims 2 to 5 in which brake lining material is attached to the support means of the trailer unit.

7. A vehicle braking system according to any one of the preceeding claims 2 to 5 in which brake lining material is attached to the support means on the tractor unit.

8. A braking system constructed and arranged for use and operation substantially as herein described and with reference to the accompanying drawings.