GB2194761A - Running gear for a trailer vehicle - Google Patents

Abstract

A low height running gear of integral unit construction with independently sprung wheels, or pairs of wheels, is suitable for trailer vehicles such as low loaders and maximum volume vans. A beam 2 has upwardly-directed aligned first brackets 3, 35 adjacent its ends for transversely attaching the beam to a trailer vehicle, aligned second brackets 4 and at least one intermediate third bracket 5 are all upstanding from the beam. The second brackets 4 may be inside, or inboard of, the respective first brackets 3, 35. Arms 8 are pivoted at forward ends respectively to a second bracket and to the, or a, third bracket 5 and carry at rearward ends stub axles 13 supporting brakes and wheel mountings. A rearwardly-extending member rigid with each arm and stub axle assembly has a platform 29 for an air spring 30. Brake actuators 26 are mounted for operating rotation of brake camshafts 21 in the forward rotational direction of the wheels 19. <IMAGE>

Description

SPECIFICATiON Running gear for a trailer vehicle It has been proposed in our British patent application no. 8425288, specification no.

2165195, to provide running gear of integral unit construction for trailer vehicles in which the wheels, or pairs of wheels, are independently sprung.

That running gear comprises an elongate beam with upwardly directed and aligned first brackets each end adapted for attachment to a vehicle. Aligned second brackets depend from the beam adjacent each end and third bracket or brackets depend from the beam intermediate the second brackets and aligned with them. First and second arms are pivotally carried at their front ends between a second bracket and a or the third bracket. Each arm has a stub axle extending transversely outwardly from the rear end of the arm to form an assembly and each stub axle carried brake means and wheel mounting means. A member extends rearwardly from each assembly and has a platform on which an air spring is mounted. Such a running gear is of relatively light and simple construction and is eminently suitable for trailer vehicles of normal standard chassis height.

It is now proposed by the present invention to provide a running gear of integral unit construction with independent springing for the wheels or pairs of wheels which is of low height and particularly suitable for the classes of trailer vehicles known as low loaders and maximum volume vans.

According to the present invention a trailer running gear comprises an elongate beam having upwardly directed and aligned first brackets rigid with said beam adjacent each end thereof, said first brackets being adapted for attachment to a vehicle so that the beam depends from and extends transversely thereof, aligned second brackets rigid with the beam adjacent each end thereof, third bracket means rigid with the beam intermediate and aligned with the second brackets, first and second arms each having a front end and a rear end and each being pivotally carried at said front end by one of said second brackets and by said third bracket means, a stub axle carried by and extending transversely outwardly from said rear end of each said arm, each said arm and said respective stub axle thereby forming an assembly, brake means and wheel mounting means on each said stub axle, and a member rigid with and extending rearwardly from each said assembly and having a platform adapted to mount an air spring thereon, wherein the said second brackets and, third bracket means extend upwardly from said beam whereby a reduced height running gear is provided.

The reduction in the height of the running gear which the present invention achieves al iows the deck of a trailer vehicle to which the running gear is fitted to be supported at a lower level and consequently the volume carrying capacity of the vehicle can be increased whilst remaining within the height restrictions imposed by legislation.

Mounting means for brake actuating means may be provided on each stub axle whereby actuating rods of said brake actuating means extend below the stub axles to brake operating mechanisms for the respective brake means.

In the prior construction of our specification no. 2165195 brake actuators are mounted on brackets secured to the stub axles adjacent their inner ends. The brackets are secured to the upper rear part of the stub axles and the brake actuator rods extend downwardly and rearwardly for operative connection to the brake camshafts. Extension of the brake actuator rods to operate the brakes results in brake camshaft rotation counter to the rotation of the wheels when the trailer to which the running gear is fitted travels forwardly.

This can be a cause of braking instability.

Having the second brackets and third bracket means extending upwardly from the beam, in accordance with the present invention, results in space being made available below the arms in which the brake actuators can be located.

This enable the brake camshafts to be rotated on brake application in the same direction as the wheels rotate when the vehicle is travelling forwards, improving braking stability.

Each first bracket may have two sides spaced from one another lengthwise of the beam.

Each second bracket may be located on the beam between the sides of a first bracket.

Alternatively, the second brackets may be located on the beam between the first brackets.

The air spring may have a lower end mounted on the platform and an upper end provided with attachment means adapted for securing to a vehicle.

Shock absorber means may be provided to act between each stub axle and its associated air spring attachment means.

An embodiment of the invention will now be described by way of example only with reference to the accompanying drawings in which: Figure 1 is a side elevation on one end of a running gear according to this invention, Figure 2 is a plan view from above of the running gear of Fig. 1 showing one half therefor, the other half being a mirror image, figure 3 is a front elevation of the half running gear shown in Fig. 2, Figure 4 is a rear elevation of the half running gear shown in Fig. 2, Figure 5 is a side elevation showing brake actuating means on a stub axle, the latter being shown in section, Figure 6 is a scrap plan view similar to Fig.

2 showing alternative arrangement of brackets of the running gear to a vehicle, and Figure 7 is a side elevation of the part of the running gear shown in Fig. 6.

In this embodiment the running gear 1 is shown with a pair of wheels for each stub axle, Fig. 2. It has a hexagonal section tubular beam 2 which has upwardly directed first brackets 3 secured to it adjacent its ends.

The beam 2 comprises similar front and rear half pressings which are welded together along their longitudinal edges. Each first bracket 3 may also comprise two similar half pressings, which are welded together at abutting front vertical edges to form the generally channel shaped bracket and then welded in place on the beam 2. The first brackets 3 have cut-outs of generally inverted troughshape in their sides so as to fit on and embrace the upper sides of the beam 2, as best seen in Fig. 1. It will also be seen that the sides of the first brackets 3 extend upwardly and forwardly from their connection to the beam so that the tops of the brackets are wider than the beam 2, Figs. 1 and 2. The brackets 3 have outwardly directed rear flanges 3A, 3B, opposed sides 3' and an angled closed front 3".

Upwardly extending second brackets 4 are secured to the beam 2 adjacent its ends.

These second brackets 4 may be located within the first brackets 3 (Fig. 2) or they may be secured inboard of the first brackets 35 (Fig. 6). They comprise generally channelshaped pressings which are welded to the beam 2. As seen in Fig. 1, the sides of the pressings have cut-outs of generally trough shape so as to fit on and embrace the upper sides of the beam 2 and have rear outwardly directed flanges 4A, 4B.

Referring to Figs. 2 and 3, an upwardly extending third bracket 5 is secured to the beam 2 towards the centre thereof. This third bracket 5 comprises a pressing similar to the pressings of the second brackets 4. Its sides have cut-outs, not shown, of generally trough shaped so as to fit on and embrace the upper sides of the beam 2, and have rear outwardly directed flanges 5A, 5B.

The brackets 3, 4, 5 are in alignment on the beam 2 and have aligned holes to receive bolts 6, 7 which retain first and second arms 8 and provide a pivotal axis for them.

Each arm 8 comprises upper and lower half pressings which are secured together, as by welding, and include side wall, a curved closing plate 9 and two bosses 11, 12. The bosses 11, 12 are bored to receive bearing bushes, not shown, and are entered into the respective brackets 4, 5 with thrust washers, not shown, and are secured therein for pivotal movement by the bolts 6, 7 and nuts 6A, 7A, respectively screwed on the bolts. The brackets 4, 5 have reinforcing plates welded to them in the region of the bolt holes.

Aligned outwardly directed stub axles 13 are secured, as by welding, to the respective arms 8. At their outer ends the stub axles carry brake assemblies represented here by brake drums 14, hubs 15 mounted on bearings, not shown, on spindle ends of the stub axle, and hub caps 16. Bolts 17 and nuts 18 are provided for securing the wheels, shown in broken lines at 19, on each hub 15. A conventional S-camshaft 21 for operating each brake is supported in a bearing 22 carried by a bracket 23 welded to and extending rearwardly from the respective stub axle 13. The camshaft 21 is splined at its inner end which is connected to an operating arm, in this example an automatic slack adjuster 24, which is pivotally connected to the operating rod 25 of a pressure air operated actuator 26.Actuator 26 is mounted on a bracket 27 which is welded to the stub axle 13 and extends downwardly and forwardly therefrom, in consequence of which the operating rod extends rearwardly below the stub axle 13. When the actuator is operated to cause application of the brake the operating rod is extended. As will be seen this results in rotation of the camshaft 21 in the same direction as the wheels rotate when the vehicle travels forwardly. This assists stable functioning of the brake. It will also be observed that the actuator 26 is so located in rear of the beam 2 as to be afforded protection from possible damage during forward travel of a trailer.

A member 28 extends rearwardly and downwardly from each stub axle, to which it is secured as by welding. Each member 28 terminates in a platform 29 to which the lower end of a known air spring 30 is secured. The upper end of the air spring 30 is secured to a plate 31 by a bolt 30A and an inflation connection 30B. The plate 31 is welded to a bracket 31A which is provided for securing the top of the air spring to the chassis or other suitable structure of the trailer vehicle.

The inner end of each stub axle 13 conveniently carries a rearwardly extending bracket 32. The inboard end of each bracket 31A includes a mounting 33 which is aligned with the bracket 32, Fig. 2. A telescopic shock absorber 34 is pivotally mounted between the bracket 32 and the mounting 33.

A bracket 2A, Fig. 2, is secured to the beam 2, as by welding, extending rearwardly towards the arm 8. This is provided as a mounting for a suspension levelling valve (not shown) which may be operatively connected between the beam 2 and the arm 8.

Referring now to the alternative constructions shown in Fig. 6 and 7, it is seen that the beam 2 is extended and the first bracket, 35, is now mounted outside the second bracket 4. This arrangement enables the first bracket 35 to be of closed hollow section, see Fig. 6, instead of the open channel shape of the first bracket 3 of the embodiment described. In side view, the first bracket 35 is of much the same shape as the bracket 3 except that it does not have the flanges 3A, 3B but has a closing rear wall 36 instead, and it encompasses less of the beam 2, extending only for the length of the front sloping side and part-way down the rear sloping side of beam 2. Aligned holes are provided in the sides of the bracket 35 in which a tube 37 is secured, as by welding, to provide a passage 37' for access to the heads of the pivot bolts 6. The tubes also stiffen the brackets 35.The broken lines 2B illustrate a further extension of the beam 2 and the broken lines 35A show an alternative position for the bracket 35. The length of the beam 2 and the spacing of the brackets 35 at each end of the beam can be varied to suit a required vehicle installation.

As can be seen from the drawings, the beam 2 is of greater depth (i.e. height) than width, as is the case in our prior construction to which reference has been made.

It will be seen that the running gear of this invention retains the advantages of the running gear described in our specification no.

2165195 whilst providing a more compact unit to allow a lower trailer vehicle platform height for increased volume carrying capacity of the trailer vehicle, and improved stability of brake functioning. If desired this running gear can, of course, be used with single wheels if suitable for the contemplated vehicle use.

Separate third brackets 5 have been described for carrying the inner bosses 12 of the arms 8. If desired a composite third bracket may be used to carry both bosses, for example as described in specification no.

2165195.

Claims (11)

1. A running gear comprising an elongate beam having upwardly directed and aligned first brackets rigid with said beam adjacent each end thereof, said first brackets being adapted for attachment to a vehicle so that the beam depends from and extends transversely thereof, aligned second brackets rigid with the beam adjacent each end thereof, third bracket means rigid with the beam intermediate and aligned with the second brackets, first and second arms each having a front end and a rear end and each being pivotally carried at said front end by one of said second brackets and by said third bracket means, a stub axle carried by and extending transversely outwardly from said rear end of each said arm, each said arm and said respective stub axle thereby forming an assembly, brake means and wheel mounting means on each said stub axle, and a member rigid with and extending rearwardly from each said assembly and having a platform adapted to mount an air spring thereon, wherein the said second brackets and third bracket means extend upwardly from said beam whereby a reduced height running gear is provided.

2. A running gear as claimed in claim 1 wherein a mounting depends from each stub axle, there is a brake actuator on each mounting, an operating rod extends from the actuator and is operatively connected to a brake camshaft such that extension of the actuator to operate the brake means causes rotation of the camshaft in the same direction as the rotation of the related trailer vehicle wheel when in use travelling forwards.

3. A running rear as claimed in claim 1 or claim 2 wherein each first bracket is of generally channel shaped horizontal cross-section having two opposed sidesspaced from one another lengthwise of the beam and a closed front and each second bracket is located on the beam within a respective one of the first brackets between the opposed sides thereof.

4. A running gear as claimed in claim 1 or claim 2 wherein the second brackets are locted on the beam between the first brackets.

5. A running gear as claimed in claim 4 wherein a passage is provided through each first bracket for access to a pivot member connecting an adjacent one of the second brackets and the front end of the associated arm.

6. A running gear assembly comprising a running gear as claimed in any preceding claim and an air spring mounted on each platform and extending upwardly therefrom, attachment means secured to the top of each air spring adapted for securing to a trailer vehicle and shock absorber means operatively connected between each stub axle and'the air spring attachment means associated with that stub axle.

7. A trailer vehicle fitted with at least one running gear as claimed in any one of claims 1 to 5.

8. A trailer vehicle fitted with at least one running gear assembly as claimed in claim 6.

9. A running gear substantially as described herein with reference to the accompanying drawings Figs. 1 to 5.

10. A running gear substantially as described herein with reference to the accompanying drawings Figs. 1 to 5 as modified by the accompanying drawings Figs. 6 and 7.

11. A trailer vehicle fitted with a running gear as claimed in claim 9 or claim 10.