TILTING TRAILERS FOR VEHICLES

Abstract: The trailer body (11) is carried on two wheels (12) and is tiltable about the wheel axle to place the edge (19) on the ground. Drawbar (16) is pivotally attached to the body (11) at (17) and is coupled to the body by a bottle screw (22) operable by a handle (23) through a ratchet (24) to effect tilting. A tension spring (34) prevents rattle and facilitates one-handed operation of the ratchet. It also aids lifting of loads placed on the rear wall (18) of the body (11).

Description: TILTING TRAILERS FOR VEHICLES This invention relates to vehicle trailers. For many purposes it is useful to be able to tip a trailer, either for off- or on-loading. This can be simply done with a two wheeled, centrally balanced trailer by detaching it from the towing vehicle and tilting the body about the wheel axle. For larger trailers, sometimes with four or more wheels, there is the altern¬ ative of pivoting the load-carrying member, such as a platform or an open-topped container with a hinged or removable tailgate, about a transverse axis at the rear. The raising of the front of the load- carrying member is generally done hydraulically. With this arrange¬ ment the trailer can remain attached to the towing vehicle, but the power required is considerable, it is sometimes a disadvantage to discharge the load from a height, and it requires an intermediate ramp for on-loading a body by sliding or rolling from the ground. There have been proposed trailers in which the draw-bar is pivotaliy connected to the chassis or load-carrying container forward of the only or rearmost wheel axle. In the towing position the container and draw-bar are locked together in a generally level attitude, but for loading, while the draw-bar remains attached to the towing vehicle the container can be tilted on the only or rear¬ most wheels, the draw-bar pivoting relative to it as well. There are various ways of securing the draw-bar and container in the towing position, effectively locking them rigidly together. In order to have some control over the tilting, one proposal has been to use a bottle-screw which can be lengthened to tilt the container and which is self-locking. However, when using commercially available bottle.-screws and fabricating the connecticns for them, it is impract¬ ical to try to achieve extremely close tolerances. It could be done, but at considerable expense and trouble. Therefore, the tendency is for there to be some looseness in the connections, and for the trailer to rattle and vibrate, thus hastening wear and widening the tolerances even further. Another problem has been in the load which can conveniently be handled. When the container is fully tilted so that its rear en is resting on the ground, a heavy load is manoeuvred to sit on the rear extremity of the container, which when level is a shallow sloping wall and which when tilted is an even shallower ramp almost level with the ground and sloping in the opposite direction. As the bottle-screw is operated to raise the container to the level position, the load can be eased forward to balance the trailer. ' But at the initial point of lift very considerable force is require to raise it. This can make the bottle-screw difficult to operate. A further difficulty lies in the operation of the bottle- screw, . A ratchet handle has been developed which can be worked to and fro to extend or reduce its length, but it still requires th operator's other hand to hold another part of the screw to achieve proper functioning. It is desirable for the ratchet to be one- handed, leaving the operator's other hand free, perhaps to guide the load. In accordance with the present invention there is provided a trailer having a draw-bar pivotaliy connected to the load-carryin structure forward of the only or rearmost wheel axle, jack means connected between the drawbar and the load-carrying structure to tilt the said structure about the said wheel axle while the draw-ba remains attached to the towing vehicle, and spring means interconne ing the draw-bar and the load-carrying structure to urge the latter towards a level attitude. Such a spring has been found to eliminate the rattles, and considerably increase the load which can be raised at the rear end of the container. Although the tilting from the level position has to be done against the action of the spring, this is quite easily achieved with a bottle screw or with a hydraulic jack. VThen a scre jack is used in conjunction with a ratchet, the spring facilitates one-handed operation of the ratchet. All trailers must carry a number plate and light assembly, and generally this will be fitted below the sloping rear end of the container. As the latter tilts, there is a danger of the number C • - ' ■ X ' plate assembly hitting the ground. A further feature described below is to link this assembly to the draw-bar so that as the con¬ tainer is tilted, ..the number plate assembly is automatically retracted. The invention will be described in more detail with the aid of an example illustrated in the accompanying drawings, in which Fig. 1 is a side elevation of a tilting trailer in accord¬ ance with the invention, Fig. 2 is a partial view of the front end of the trailer, and Fig. 3 is a detail section on the line III-ill in Fig.2. The trailer has a load-carrying container 11 which is mounted on a pair of wheels 12 rotating about a wheel axle 13. The wheel axle is formed by two stub axles each of which is carried on a swing link 14 attached to the base of the container 11 by a torsion spring 15. The trailer is towed by means of a draw-bar 16 connected to the front of the container 11 by a pivot 17 whose axis is parallel to the wheel axle 13. The container 11 is an open box¬ like structure, generally rectangular but with a rear wall 18 which, when the trailer is in the towing position shown, slopes upwardly and rearwardly at a shallow angle. When the container is tilted about the axle 13, the rear edge 19 of this wall 18 will touch the ground, and the wall 18 will slope up from that edge at a very shallow angle. A bracket 20 projects upwardly and forwardly from the centre of the top of the front wall of the container 11. A winch 21 is carried on this bracket, and is manually operable to help draw loads on to the trailer when tilted. Between the bracket 20 and the draw¬ bar 16 there is a bottle-screw 22 operable by a handle 23 through a ratchet device 24, which can be switched either to lengthen or shorten the bottle-screw as the handle is worked to and fro. As the bottle-screw is extended, the container will tilt about the axle 13, while the draw-bar 16 can still remain attached to the towing vehicle. When the trailer is being towed, the container 11 is adjusted to be level, and the bottle-screw 22, although to a_ great extent self- locking, can be further secured by a locking tab 25. Referring to Fig.2 it will be seen that the bottle-screw 22 comprises two couplings 26 and 27 pivotaliy connecting the bottle screw with the draw-bar 16 and the bracket 20, respectively. Two threaded pins 28 and 29 of opposite hand are screwed into the ends of the body 30 of the bottle screw so that upon rotation of the body the pins 28 and 29 are forced apart or pulled together. Rotation of the body 30 is effected by using the handle 23 to swing an arm 31 (Fig.3) which engages a ratchet wheel 32 by way of a reversible pawl 33. The locking tab 25 is threaded on the pin 29 and acts as a lock nut against the end of the body 3θ- There also acts between the bracket 20 and the draw-bar 16 a power ul coiled tension spring 3 . This urges the container 11 towards the level position, and assists in raising loads placed on the rear wall 18, but it can be overcome, for tilting the trailer, by operation of the bottle-screw 22. Below the sloping rear wall 18 there is suspended a number plate and light assembly 35. The assembly 35 is hinged and is provided with a clip 36 engageable with the underside of the wall 18 to hold the assembly 35 in a folded back position when the trailer i being tipped. In an alternative construction the folding back of the number plate assembly is effected automatically as the body 11 tilts by means of a cable coupling the assembly to the draw-bar and pulling against a spring bias. As suggested above, there can be different means for tilting the container, for example a hydraulic jack. This also is self- locking, which is desirable since not all towing points are at the same height and it is useful to be able to set the container level whatever the towing vehicle. If the draw-bar were secured by, say, a locking pin such an infinitely adjustable feature would not be possible. A pneumatic ram would also be possible, and particularly with that type of piston and cylinder actuator the spring could be internal, acting between the piston and one end of the cylinder, and conveniently being in the chamber where it can act as a compression spring. The pump (and reservoir in the case of the hydraulic jack) can be mounted on the draw-bar or on the container. A coil spring is not the only possibility. For example a leaf-type spring might project forwardly from below the container to act on the underside of the draw-bar.

Claims: CLAIMS : 1. A trailer having a draw-bar pivotaliy connected to the load-carrying structure forward of the only or rearmost wheel axle, jack means connected between the drawbar and the load-carryi structure to tilt the said structure about the said wheel axle whi the draw-bar remains attached to the towing vehicle, and spring means interconnectingthe draw-bar and the load-carrying structure to urge the latter towards a level attitude. 2. A trailer as claimed in claim 1 in which the jack means is a screw jack. 3. ' A trailer as claimed in claim 2 in which the screw jack is a bottle screw. 4. A trailer as claimed in claim 3 or 4 in which the jack means .includes a reversible ratchet operable by a swingable arm to lengthen or shorten the jack means. 5. A trailer as claimed in any of the preceding claims in which the spring means comprises a coiled tension spring.

Inventors: SNELL T
Applicants: MASTERNET LTD, SNELL T
Application year: 1981
Main classification: B60P1
IPC codes: B60P1, B62D53, B62D63