GB2126172A - Tipping vehicle - Google Patents

Abstract

A body (1) can be elevated relative to a wheeled chassis (2) by one or more actuators (4), pairs of links (10, 11) on each side of the vehicle connecting the body (1) to the chassis (2) rearwardly of the actuator(s) (4) are arranged so that, as the body is tipped it is moved forwardly and upwardly relative to the chassis, to counter the tendency to jacknife. <IMAGE>

Description

SPECIFICATION Tipping vehicle This invention reiates to tipping vehicles generally and is particularly, but not exclusively applicable to agricultural trailers having tipping bodies.

A risk associated with the operation of tipping trailers, particularly high-sided agricultural trailers, is that of jacknifing. This occurs when the trailer body is tipped rearwardly to dump its load: if the centre of gravity of the load trailer moves rearwardly beyond the rear wheel axle of the trailer the resulting turning moment about the wheel axle can be sufficiently large, particularly when the trailer is heavily loaded, to lift the front end of the trailer and the rear end of the tractor coupled to the trailer. This jacknifed condition of the tractor and trailer is potentially very hazardous, and various arrangements have been proposed for countering the tendency of a tractor-trailer combination to jacknife in this way.

Among earlier anti-jacknifing arrangements proposed for tipping trailers is one of which, upon tipping of the trailer, the rear wheel axle of the trailer is displaced towards the rear, by a suitable linkage or actuator so that the centre of gravity of the loaded trailer body does not pass over the wheel axis as the body is tipped. In this connection reference is made to the applicant's published European Patent Application No. 0001020.

The present inventionseeks to provide a tipping trailer or other vehicle in which upon tipping of the vehicle body, the centre of gravity of the body is displaced forwardly, so that the tendency of overbalance orjacknife is effectively countered by ensuring that as the body is tipped its centre of gravity moves rearwardly by a sufficiently small amount to prevent jacknifing.

According to the present invention there is provided a trailer or other vehicle comprising a wheeled chassis supporting a tippable body which is elevated and lowered relative to the chassis by operation of one or more actuators, the body being connected to the chassis at its rear end by links pivotally connected to the vehicle body and to the chassis, on each side of the latter, in which the links are disposed rearwardly of the actuator or actuators and are so arranged that, upon extension of the actuator or actuators, the front end of the body is elevated to tip the body relative to the chassis while the centre of gravity of the body is simultaneously displaced forwardly relative to the chassis.

Preferably the links on each side of the vehicle are pivotally connected to the body and to the chassis about pivot axes located rearwardly of the pivotal connections of the actuator or actuators to the body and to the chassis. In a preferred embodiment the body is connected to the chassis by a pair of links on each side of the vehicle, each pivotally connected to the body and to the chassis, each pair of links forming a quadrilateral linkage.

By suitable selection of the lengths of the links forming each pair, and of the location of the pivotal connection of these links to the body and the chassis, it is arranged that as the body is elevated relative to the chassis the links swing forwardly about their pivotal connections to the chassis, elevating the rear end of the vehicle body while at the same time dispiacing the body forwardly. In consequence, the rearward travel of the centre of the gravity of the body upon tipping of the latter is significantly less than that which would occur in a body having a fixed pivotal connection to the chassis, and the tendency of the tipping body to overbalance orjacknife is substantially reduced.Moreover, the links ensure that as the body is elevated upon tipping the distance of the rear end of the body from the ground is increased, assisting the tipping or dumping action.

In a preferred embodiment of the invention the pivotal connections of each pair of links to the body are closer together than the pivotal connections of the said links to the chassis.

According to one embodiment of the invention, the two links of each respective pair of links are pivotally connected to the chassis through pivotal connections to a respective mounting plate fixed to a rear wheel axle of the chassis.

In a preferred embodiment, however, the upper link of each pair of links has a pivotal connection directly to the vehicle chassis and the lower link of said pair has an indirect pivotal connection to the chassis, being pivotally connected to a mounting plate fixed to a rear wheel axles of the chassis.

The invention will be further described, by way of example only, with reference to the accompanying purely diagrammatic drawings, in which: Figure 1 is a schematic side elevation of a tipping trailer having a fixed tipping axis, exemplifying a typical known arrangement for such a vehicle; Figure 2 is a schematic side elevation, corresponding to Figure 1 and illustrating the tipping operation of a trailer in accordance with the invention; Figure 3 is a diagrammatic side elevation showing essential elements of a tipping trailer according to one embodiment of the invention, and Figure 4 is a side elevational view, partsectioned on an enlarged scale compared witb Figure 3, showing a practical arrangement of the component parts of a tipping trailer for a single axle trailer vehicle in accordance with another embodiment of the invention.

The same reference numerals are used throughout the drawings to designate the same or equivalent components in different embodiments of the invention.

Figure 1 illustrates a know type of tipping trailer in which a trailer body 1 is supported on a wheel chassis 2 for tipping movement about a rear horizontal axis 3, tipping movement being effected hydraulically by actuators (not shown). In the case of a trailer having a high-sided body 1, such as, for example, an agricultural trailer, the centre of gravity of the loaded trailer, G, will be approximately in the position shown, normally forwardly of the vertical plane P containing the trailer wheel axle, or the axle of the rearmost wheels of the trailer, in the case of a multiaxle trailer.

When the trailer body 1 is tipped it pivots about the rear axis 3 to an elevated position shown in broken outline in Figure 1, in which the centre of gravity G is displaced upwardly and rearwardly to a position G' which is to the rear of the plane P.

The weight of the loaded trailer body 1 acting at the displaced centre of gravity G' produces a tipping moment about the line of contact of the plane P with the ground, this tipping moment being anticlockwise as depicted in Figure 1, and tending to lift the front of the trailer and the rear of the tractor (not shown) connected to the trailer off the ground. This is the dangerous overbalancing of jacknifing condition which the present invention seeks to avoid.

Referring to Figure 2, where the same reference numerals are used to designate parts corresponding to the trailer illustrated in Figure 1 the present invention provides a trailer having a tipping body 1 which, upon being tipped relative to a supporting wheeled chassis 2 is elevated and displaced by a linkage, in a manner to be described, so that the body 1 as it is tipped, is displaced upwardly and forwardly. As a result, the centre of gravity G of the trailer body 1 is displaced to a position G" which is only slightly to the rear of the vertical plan P containing the rear axle of the trailer. In consequence, the turning moment exerted by the weight of the loaded trailer body 1 in its elevated position is insufficient to cause overbalancing orjacknifing of the trailer.

Moreover, the upward displacement of the trailer body 1 upon tipping assists the dumping of the load from the trailer body onto the ground since the rear of the tipped trailer body is less likely to foul the dumped load than is the case when the trailer body 1 tips about a fixed axis 3, as in Figure 1.

The mechanism for effecting the upward and forward displacement of the trailer body 1 upon tipping is illustrated in Figures 3 and 4 as applied to a trailer having a single rear wheel axle.

Elevation of the vehicle body 1 relative to the chassis 2 is effected by means of an hydraulic actuator 4 having a pivotal connection 5 at its lower end to a mounting plate 6 fixed to the rear wheel axle 7 inwardly of the wheels 8. At its upper end the piston rod of the actuator 4 has a pivotal connection 9 to a suitably positioned lug on the elevating body 1.

In place of a fixed hinge connection between the chassis 2 and the body 1 the trailer of the present invention is provided with an elevating linkage consisting of two pairs of links, one pair of links 10, 11 being shown in Figures 3 and 4. The two links 10, 11 have respective pivotal connections 12, 1 3 to the chassis 2 and respective pivotal connections 14, 1 5 to a lug 1 6 on the vehicle body 1, to the rear of the axle 7. The two links 10, 11 are of substantially equal length, and are each constructed from rigid box section.

The two pivotal connections 14, 1 5 on the body 1 are closer together than the pivotal connections 12, 13 on the chassis 2.

The two pivotal connections 12, 13 on the chassis 2 may be provided on the mounting plate 6 fixed to the axle 7, as shown in Figure 4. This places a considerable strain on the mounting plate 6, however, and an alternative arrangement is illustrated in Figure 3, in which the pivotal connection 13 is carried by the mounting plate 6 while the pivotal connection 12 is spaced further from the connection 13, being provided on an upstanding bracket 1 2A welded to the chassis frame.

A second pair of links corresponding to the links 10, 11 is arranged symmetrically on the opposite side of the longitudinal centre line of the vehicle, and is attached to a corresponding axle mounting plate (not shown) attached to the wheel axle 7, together with a second hydraulic actuator corresponding to the actuator 4. The arrangement of this second pair of links and the actuator is essentially the same as that illustrated in Figures 3 and 4. The links of the second pair are rigidly connected by lateral bracing struts (not shown) to the corresponding links 10, 11 of the first pair, to resist any tendency for lateral twisting of the linkage during raising and lowering of the body 1.

Each pair of links 10, 11 forms with its four points of connection to the chassis and the body a quadrilateral linkage. Upon elevation of the vehicle body 1 by extension of the or each actuator 4 the links 10, 11 swing upwardly and forwardly to the position shown in broken outline in Figures 3 and 4, the pivotal connections 14, 1 5 to the vehicle body moving in respective arcuate paths 17, 18, as shown in Figure 3. The two pairs of links 10, 11 effectively guide the elevation of the body 1 causing it to adopt a tipped position in which it is displaced both forwardly and upwardly from its normal rest position, as shown in broken outline in Figures 3 and 4.

Upon restriction of the actuator or actuators 4 the body 1 is lowered onto the chassis 2, and the links 10, 11 return to their original position, as illustrated in full lines, guiding the rear of the body 1.

It will be appreciated that the invention as described is equally applicable to trailers or other vehicles having multiple axles. For a multiple axle trailer, for example, the mounting plate for each actuator and elevating linkage would be attached to a rigid transverse frame member to which a pivoted yoke or balance beam of the multiple axle unit is also attached.

Claims (9)

1. A trailer or other vehicle comprising a wheeled chassis supporting a tippable body which is elevated and lowered relative to the chassis by operation of one or more actuators, the body being connected to the chassis at its rear end by links pivotally connected to the vehicle body and to the chassis, each side of the latter, in which the links are disposed rearwardly of the actuator or actuators and are so arranged that, upon extension of the actuator or actuators, the front end of the body is elevated to tip the body relative to the chassis while the centre of gravity of the body is simultaneously displaced forwardly relative to the chassis.

2. A trailer or other vehicle according to Claim 1, in which the links on each side of the vehicle are pivotally connected to the body and the chassis about pivot axes located rearwardly of the pivotal connections of the actuator or actuators to the body and to the chassis respectively.

3. A trailer or other vehicle according to Claim 1 or Claim 2, in which the body is connected to the chassis by a pair of links on each side of the vehicle, each pivotally connected to the body and the chassis, each pair of links forming a quadrilateral linkage.

4. A trailer or other vehicle according to Claim 3, in which the pivotal connections of each pair of links to the body are closer together than the pivotal connection of the said links to the chassis.

5. A trailer or other vehicle according to Claim 4, in which the pivotal connections to the chassis of each pair of links is located above a rear wheel axle and the pivotal connection to the chassis of the lower link of said pair is located below the rear wheel axle.

6. A trailer or other vehicle according to Claim 5, in which the pivotal connection to the chassis of the said upper link of each pair is located forwardly of the rear wheel axle and the pivotal connection to the chassis of the lower link of said pair is located rearwardly of said axle.

7. A trailer or other vehicle according to any one of Claims 3 to 6, in which the upper link of each pair of links has a pivotal connection directly to the vehicle chassis and the lower link of said pair has an indirect pivotal connection to the chassis, being pivotally connected to a mounting plate fixed to a rear wheel axle of the chassis.

8. A trailer or other vehicle according to any one of claims 3 to 6, in which the two links of each respective pair of links are pivotally connected to the chassis through pivotal connections to a respective mounting plate fixed to a rear wheel axle of the chassis.

9. A trailer or other vehicle substantially as herein described with reference to and as shown in Figures 2 to 4 of the accompanying drawings.