GB2115373A - Improvements in or relating to skip-handling vehicles - Google Patents

Abstract

This invention relates to skip- handling vehicles, and it is an object of the invention to provide a vehicle in which a skip can be lifted clear of the rear of the vehicle with shorter lifting arms than would be required in known skip-handling vehicles. In accordance with the invention, each lifting arm comprises a triangular frame consisting of a base member (14), an upstanding member (15) perpendicular to the base member (14), and an inclined member (16). Transverse shafts (24 and 25) join the base members of the two lifting arms, and the ends of these shafts are guided in arcuate slots (26 and 27) in guide plates (7) secured to the chassis of the vehicle. The arrangement is such that, when the skip is on the vehicle, the two lifting arms can be pivotted about the shaft (25) to raise the skip. This pivotting movement continues until the member (15) is vertical. Continuing movement to unload the skip is produced by pivotting of the two lifting arms about the axis of the shaft (24). Jack legs (3 and 4) are provided to prevent tipping of the vehicle about the axis of the rear wheels when the skip is outboard of the vehicle. <IMAGE>

Description

SPECIFICATION Improvements in or relating to skip-handling vehicles This invention relates to skip-handling vehicles, the term being used herein to include not only a power-driven vehicle, but also a road vehicle adapted to be drawn by a power-driven vehicle.

Skip-handling vehicles are known in which a skip is loaded on to and off the vehicle by means of a pair of lifting arms pivotable about a transverse axis fixed in the vehicle. The arms are hydraulically controlled by means of a pair of hydraulic cylinders, one on each side of the vehicle. Normally, in addition, a pair of hydraulically operated stabilising jacks are provided to prevent the vehicle from tipping when a heavy skip is being lifted.

From one aspect the present invention consists in a skip-handling vehicle including a pair of lifting arms pivotable about two parallel transverse axes spaced apart in the direction of the fore-and-aft axis of the vehicle, and hydraulic means for causing pivotal movement of said arms, a first part of said pivotal movement taking place about one of said two axes, and a second part of said pivotal movement taking place about the other of said two axes.

From another aspect the invention consists in a skip-handling vehicle including a pair of lifting arms pivotable about two parallel transverse axes spaced apart in the direction of the fore-and-aft axis of the vehicle, and hydraulic means for controlling said arms, the arrangement being such that, as the distal ends ofthe arms are moved from a forward to a rearward position under the control of said hydraulic means, the pivotting of the arms is transferred from the more forward of said two transverse axes to the more rearward of said axes and vice-versa.

It is to be understood that the provision of the two pivot axes enables a skip to be lifted clear of the rear of the vehicle with shorter lifting arms than would be required if the arms were pivotted in the conventional manner about a single pivot axis.

Preferably each of the lifting arms is in the form of a triangular frame. The frame comprises a base member; a first upstanding member substantially perpendicular to said base member; and an inclined member joining the distal end of the upstanding member to the end of the base member remote from the upstanding member. Preferably the upstanding member is forward of the inclined member with respect to the fore-and-aft axis of the vehicle.

Preferably, so far as each of the lifting arms is concerned, the more forward of the two transverse axes is located substantially at the junction between the upstanding member of the frame and the base member, while the more rearward of the two transverse axes is located at the juction between the inclined member and the base member of the frame.

Preferably the two arms are controlled by respective hydraulic cylinders, the cylinder in each case being pivotally connected to the upstanding member of the respective frame.

It is to be understood that the two transverse axes are fixed in the lifting arms. Accordingly, when pivotting of the arms takes place about the more rearward of said axes, that axis is also fixed relative to the vehicle. Similarly, when pivotting of the arms takes place about the more forward axis, that axis is fixed in the vehicle as well as in the arms. It will also be understood that, while the arms are pivotting about the more rearward axis, the more forward axis follows an arcuate path relative to the vehicle.

Similarly, while the arms are pivotting about the more forward axis, the more rearward axis follows an arcuate path relative to the vehicle. These requirements may be fulfilled by providing means to lock the more forward axis to the vehicle when pivotting is taking place about that axis, and to lock the more rearward axis to the vehicle when pivotting is taking place about that axis. However, in a preferred embodiment of the invention, the required action is brought about by guiding both axes to follow the required arcuate paths. The geometry ofthe arrangement is such that, while the more forward axis is moving along its defined arcuate path, the more rearward axis is unable to move from the lowermost end of its arcuate path.Similarly, while the rearward axis is moving along its defined arcuate path, the more forward axis is unable to leave the lowermost end of its arcuate path.

Preferably the arrangement is such that the more forward axis is effectively locked to the vehicle when the upstanding member of the frame is inclined forwardly with respect to the vehicle chassis, whereas the more rearward of the transverse axes is effectively locked to the chassis when the upstanding member is inclined rearwardly with respect to the vehicle chassis. When the upstanding member is upright, both of the transverse axes are located at the lowermost ends of their respective arcuate paths.

Preferably a pair of jacks are mounted on the vehicle chassis in the vicinity of the rear of the chassis. These jacks are linked to the lifting arms so that they are raised when the upstanding members are inclined forwardly and lowered when the upstanding members are inclined rearwardly.

One method of performing the invention will now be described with reference to the accompanying diagrammatic drawings, in which Figure 1 is a side view of a vehicle in accordance with the invention with the skip loaded on the vehicle; Figure 2 is a rear view, partly in section, of the vehicle as illustrated in Figure 1; Figure 3 is a side view of the vehicle illustrated in Figure 1 with the skip raised to an intermediate position for loading or unloading; and Figure 4 is a side view of the vehicle illustrated in Figures 1 and 3 with the skip on the ground.

The embodiment illustrated includes a vehicle chassis 10 supported on four wheels -two of which are shown at 11 and 12. Mounted on the chassis are two lifting arm assemblies, each of which includes a base member 14, an upstanding member 15, and an inclined member 16. Fitted on each of the upstanding members 15 is a trunnion 17 to which is pivotally attached the piston of a hydraulic cylinder 19. The remote end of each cylinder 19 is pivotally attached to the vehicle chassis 10 by means of a trunnion 20.

The distal ends of the members 15 and 16 are interconnected and a transverse shaft 18 extends between the two interconnected ends. Chains 21 extend from the shaft 18 to support a skip 23 being attached to spigots 22 provided on the skip.

A shaft 24 extends across the width of the vehicle between the junctions of the inclined members 16 and the base members 14 of the two lifting arm assemblies. A further shaft 25 also extends across the vehicle between the junctions of the upstanding members 15 and the base members 14. A guide plate 7 is fixed to the chassis on each side of the vehicle, and is provided with two arcuate slots 26 and 27. The shaft 25 is constrained to travel in the slots 26 and the shaft 24 is constrained to travel in the slots 27. Each end of each of the shafts is enlarged as shown, for example, at 5 and 6 in Figure 2 in the case of the shaft 24. These enlarged ends prevent lateral movement of the shafts relative to the vehicle chassis.

As can be seen from Figure 1, when the skip 23 is located on the vehicle, the upstanding members 15 of the two lifting arms are inclined forwardly with respect to the vehicle. The shaft 25 is located at the lowermost ends of the slots 26, while the shaft 24 is located at the uppermost ends of the slots 27. If the pistons of the cylinders 19 are extended, the lifting arms will be caused to rotate in a clockwise direction as seen in Figure 1 about the axis of the shaft 25.

Under these conditions, the shaft 24 is constrained to travel down the arcuate slots 27 and the geometry is such that the shaft 25 cannot travel up the arcuate slots 26 until the shaft 24 has reached the lowermost ends of the slots 27.

Figure 3 of the drawings shows the intermediate position when the upstanding members 15 are perpendicular to the vehicle chassis. At this stage, the shaft 25 is at the bottom of the slots 26, while the shaft 24 has reached the bottom of the slots 27. At this point, pivotal movement is transferred from the axis of the shaft 25 to the axis of the shaft 24. Further extension of the piston 18 of the cylinder 19 causes the lifting arms to reach the eventual position illustrated in Figure 4. During the transition from the position shown in Figure 3 to the position shown in Figure 4, the shaft 25 has travelled along the slots 26, while the shaft 24 has remained at the bottom of the slots 27.

It is to be understood that, while the lifting arms are in any position between that shown in Figure 1 and that shown in Figure 3, the shaft 24 will apply radially outward forces to the rearward edges of the slots 27. Accordingly, to prevent wear on the material of the guide plates 7 and on the parts of the shaft 24 engaging the guide plates, it is preferable to provide arcuate bearing members along the rearward edges of the slots 27 engaging the respective enlarged ends of the shaft 24. Similarly, when the lifting arms are in any position between that illustrated in Figure 3 and that illustrated in Figure 4, the shaft 25 will apply radially outward forces to the forward edges of the slots 26. Accordingly, similar bearing members will be provided along the forward edges of the slots 26 to engage the enlarged ends of the shaft 25.

As the lifting arms are moved from the position illustrated in Figure 3 to the position illustrated in Figure 4, the weight of the skip will apply forces to the vehicle tending to raise the front end of the vehicle off the ground. Accordingly, jack legs 3 and 4 are provided to support the rear of the chassis under these conditions. Each of the jack legs is pivotally mounted on the chassis by means of a pair of trunnions 31 and 32. The position of the legs is controlled by respective pairs of links 33 and 34.

Each of these pairs of links is pivotally connected at one end to the respective jack leg and, at the other end, to the transverse shaft 24.

Thus when the skip is on the vehicle as shown in Figure 1, the shaft 24 is at the uppermost end of the slots 27 and raises the two jack legs 3 and 4 clear of the ground. On the other hand, when the lifting arms reach the position shown in Figure 3, the shaft 24 is at the bottom end of the slots 27 and, accordingly, the legs 3 and 4 are lowered. The drawings illustrate the conditions prevailing when there is no load in the slip and, accordingly, the legs 3 and 4 are shown in Figures 3 and 4 as being clear of the ground.

However, it is to be understood that, with a load in the skip, the springs of the vehicle would be deflected so that, as the skip was moved from the position illustrated in Figure 3 to that illustrated in Figure 4, the shoes on the lower ends of the jack legs 3 and 4 would engage the ground.

While the invention has been described with reference to a four-wheeled vehicle it is, of course, to be understood that it may be applied to any trailer or power-driven vehicle irrespective of the number of wheels.

It is further to be understood that in some circumstances the transverse shaft 18 may be omitted. The shafts 24 and 25 provide sufficient support for the lifting arm assemblies and omission of the shaft 18 permits the use of skips higher than that shown in the drawings.

Claims (14)

1. A skip-handling vehicle including a pair of lifting arms pivotable about two parallel transverse axes spaced apart in the direction of the fore-and-aft axis of the vehicle, and hydraulic means for causing pivotal movement of said arms, a first part of said pivotal movement taking place about one of said two axes, and a second part of said pivotal movement taking place about the other of said two axes.

2. A skip-handling vehicle including a pair of lifting arms pivotable about two parallel transverse axes spaced apart in the direction of the fore-and-aft axis of the vehicle, and hydraulic means for controliing said arms, the arrangement being such that, as the distal ends of the arms are moved from a forward to a rearward position under the control of said hydraulic means, the pivotting of the arms is transferred from the more forward of said two transverse axes to the more rearward of said axes and vice-versa.

3. A vehicle as claimed in Claim 1 or Claim 2, wherein each of the lifting arms is in the form of a triangular frame comprising a base member, a first member upstanding from said base member, and a second member joining the distal end of the first member to the end of the base member remote from the first member.

4. A vehicle as claimed in Claim 3, wherein each of the first members is substantially perpendicular to the respective base member.

5. A vehicle as claimed in Claim 4, wherein each of the first members is forward of the second member with respect to the fore-and-aft axis of the vehicle.

6. A vehicle as claimed in any of Claims 3 to 5, wherein said transverse axes are fixed in the lifting arms, one being located substantially at the junction between the base member and the first member and the other being located at the junction between the second member and the base member.

7. A vehicle as claimed in any of the preceding Claims, wherein the two lifting arms are controlled by respective hydraulic cylinders pivotally connected to the vehicle chassis and the respective lifting arm.

8. A vehicle as claimed in any of the preceding Claims, including means for guiding each of said axes to follow an arcuate path fixed in the vehicle when pivotal movement is taking place about the other of said axes.

9. Avehicle as claimed in Claim 8, wherein the geometry of the arrangement is such that, while each axis is moving along its defined arcuate path, the other axis is unable to move from the lowermost end of its arcuate path.

10. A vehicle as claimed in Claim 5, wherein the arrangement is such that the more forward axis is effectively locked to the vehicle when the first member of each frame is inclined forwardly with respect to the vehicle chassis, whereas the more rearward of the transverse axes is effectively locked to the chassis when the first member is inclined rearwardly with respect to the chassis.

11. Avehicle as claimed in Claim 8 and Claim 10, wherein, when each of the first members is upright, both of the transverse axes are located at the lowermost ends of their respective arcuate paths.

12. A vehicle as claimed in any of the preceding Claims, wherein a pair of jacks are mounted on the vehicle chassis in the vicinity of the rear of the chassis, these jacks being linked to the lifting arms so that they are raised when the arms are inclined forwardly and lowered when the arms are inclined rearwardly.

13. A skip-handling vehicle substantially as hereinbefore described with reference to, and as illustrated in, the accompanying diagrammatic drawings.

14. Any features of novelty, taken singly or in combination, of the skip-handling vehicle as hereinbefore described with reference to the accom panying diagrammatic drawings.