GB2153339A

GB2153339A - Fork lift agricultural trailer

Info

Publication number: GB2153339A
Application number: GB08502028A
Authority: GB
Inventors: Thomas Davis
Original assignee: Individual
Current assignee: Individual
Priority date: 1984-01-28
Filing date: 1985-01-28
Publication date: 1985-08-21
Also published as: IE831782L; GB8502028D0

Abstract

Trailer 1 has an elongate frame made up of longitudinal channels 2 and 3 and transverse members 6 and 6a. A fork-lift mast assembly 8 has a base portion including lateral members 10 carrying rollers 30 accommodated within the channels 2 and 3 so that the mast assembly may be displaced longitudinally along the length of the trailer between an extended position and a retracted position. In the extended condition, the forks 9 are located rearwardly of the frame so that they may be lowered to the ground, while in the retracted condition they are located inboard on the trailer frame, so that a load may be carried in a stable manner with its centre of gravity located between the wheels 5 and the coupling 7a. Hydraulic rams 24 and 23 control longitudinal displacement of the assembly and the raising and lowering movement of the forks 9 respectively. The upwardly-extending part of the mast may also be tilted relative to the base portion by further hydraulic rams 24. <IMAGE>

Description

SPECIFICATION Fork-lift agricultural trailers This invention relates to agricultural trailers and in particular, to an agricultural trailer including fork-lift means.

In order to handle palletised materials on farms, such as for example, bagged fertiliser, it is known to mount a detachable fork-lift unit on the standard three-point linkage at the back of a tractor. There are a number of disadvantages associated with this arrangement, among them the fact that mounting of the fork unit on the tractor is relatively timeconsuming. In addition, if it is desired to handle the two-ton loaded pallets which are standard in the distribution of fertiliser, a relatively powerful tractor must be used, and it may be necessary to equip it with a counterbalance. Further disadvantages may arise if the fertiliser is to be unloaded at a location where the pallet cannot readily be set down.

The tractor will be tied up until such time as the pallet is unloaded.

It is an object of the present invention to provide an agricultural trailer suitable for the handling of materials such as palletised fertiliser, which will minimise or eliminate at least some of the disadvantages of the tractormounted fork-lift arrangement described above.

According to the invention, there is provided a trailer for agricultural use comprising an elongate frame having wheels in the region of one longitudinal or elongate end of the frame and means for coupling the frame to a tractor unit in the region of the other longitudinal or elongate end of the frame, and a forklift mast assembly displaceably mounted on the frame for movement relative to the frame in the longitudinal or elongate direction of the frame between an extended position in which the forks of the mast assembly are disposed substantially rearwardly of the frame and a retracted position in which the forks are disposed substantially inboard of the trailer.

In a preferred construction, the fork-lift mast assembly has a base portion mounted on the frame by support means and said elongate frame has guide means for guiding said support means during said relative displacement of the mast assembly and frame. The frame may include two inwardly opening channel members defining said guide means and the base portion of the fork-lift mast assembly may then be mounted on the frame by rollers defining said support means and disposed within said channel members for displacement relative to the channel members in the longitudinal or elongate direction of the frame.

Displacement of the mast assembly along the frame is most suitably achieved by a hydraulic ram, the piston of which is preferably attached at its outboard end to a transverse member of the base portion of the mast assembly, the cylinder of the ram then being connected to a transverse member of the frame.

The fork-lift mast assembly may include an upwardly-extending portion consisting of a first section associated with said base portion of the mast assembly and a second section displaceable relative to said first section. Said first section of the upwardly-extending portion of the fork-lift mast assembly preferably has guide means for guiding said displaceable second section of the upwardly-extending portion of the mast assembly during said relative displacement of said first and second sections.

Said first section of the upwardly-extending portion of the mast assembly may suitably include inwardly opening channel members defining said means for guiding said second section and the displaceable second section may then be slideable in a substantially vertical direction within these channel members.

As in the case of the other motions of the trailer mast assembly, this substantially vertical displacement may be brought about by a hydraulic ram, the piston of which is attached or coupled at its outboard end to a transverse member of one of the mast assembly sections and the cylinder of which is attached to a transverse member of the other of the sections.

The upwardly-extending portion of the mast assembly is in a particularly preferred construction pivotably associated with the base portion of the mast assembly. One or more hydraulic rams then suitably extend between and are pivotably connected to the upwardlyextending portion of the mast assembly and the base portion of the mast assembly for tilting the upwardly extending portion relative to the base portion.

The forks of the mast assembly are typically associated with the displaceable section of the upwardly-extending portion of the mast assembly and the mast assembly then suitably includes guide means for guiding the forks during raising and lowering of the forks. The forks of the mast assembly are preferably substantially fixedly associated, at least for lifting and lowering movements, with the substantially vertically displaceable section of the mast assembly and are guided during such raising or lowering by suitable guide means.

which may be the channels of the fixed or pivotable section of the mast assembly, i.e.

the first section. The forks may however be removable from the trailer so that the unit can be interchangeably equipped with forks of different dimensions, e.g. varying in length and/or width, as required. The lateral spacing of the forks may also be adjustable. However during use of the trailer, the movement of the forks is governed by the movements of the mast assembly.

The leading end of the trailer is preferably equipped with a standard trailer hitch, so that it can be coupled to the rear of a normal agricultural tractor. The hydraulic supply for the various rams of the trailer may be taken from the tractor hydraulic system. Preferably the trailer is equipped with a counter-weight near its leading end to ensure that excessive vertical loads are not applied to the tractortrailer coupling. The leading end of the trailer may also be provided with means for supporting it above ground level when uncoupled from a tractor.

The trailer according to the invention provides a convenient means for handling and moving large pallets of material such as fertiliser about a farm. By providing it with a suitable type of wheel, it can readily be used both in fields and on rough ground and also on more level surfaces such as farm roadways and paved yards.

The invention also provides a trailer for agricultural use comprising an elongate frame having wheels at one end and means for coupling the frame to a tractor unit at the opposite elongate end of the frame, and a fork-lift mast assembly displaceably mounted on the frame, the mast assembly being displaceable along the frame in the elongate direction of the frame between an extended position in which the forks of the mast assembly are disposed rearwardly of the rearmost portion of the frame and a retracted position in which the forks are disposed inboard of the trailer.

An embodiment of the invention will now be described having regard to the accompanying drawings, in which: Figure 1 shows a pictorial view of a trailer according to the invention, Figure 2 is a side view of the trailer of Fig.

1 in a loading or unloading configuration with certain details omitted and part of one side channel cut away at the rear end, Figure 3 is a rear view of the trailer of Fig.

1. and Figure 4 is a side view of the trailer of Fig.

1 in a transport configuration, with the forks in a raised postion and the mast assembly part retracted.

As shown in Fig. 1, the trailer 1 according to the invention has an elongate frame including channel members 2 and 3 extending in the elongate direction of the trailer. A fixed axle or transverse member 4 spans the width of the trailer at its rear end and wheels 5 are rotatably mounted at the outer ends of the axle 4. The channel members 2 and 3 extend somewhat to the rear of the transverse axle 4.

At its leading end, the trailer has transverse members 6 and 6a, which may be of channel or box configuration, affixed to the lower sides of the leading ends of the channel members 2 and 3. A substantially straight towbar 7 is provided at the leading end of the trailer and is connected to both the front transverse member 6 and the secondary transverse mem ber 6a. The coupling arrangement is a stan dard trailer hitch, indicated schematically only at 7a.

A fork-lift mast assembly 8 is mounted on the frame of the trailer 1 for displacement along the length of the trailer between an extended position in which the forks 9 of the mast assembly are disposed rearwardly of the transverse fixed axle 4 and a retracted position in which the forks are forward of that member. The mast assembly is shown in a part retracted condition in Figs. 1 and 4 of the drawings and in its extended position in Fig. 2. The mast assembly consists of a base portion and an upwardly-extending portion.

The base portion has lateral base members 10 disposed in part within the channels of the members 2 and 3 and extending in the longitudinal direction of the channels. The mem bers 10 are mounted on rollers 30 also ac commodated within the channels, so that the mast assembly can travel along the length of the trailer frame, the rollers bearing on the inner surfaces of the lower flanges of the channel and being guided by the channels The base portion also has front and rear transverse members 11 and 11 a respectively bridging the space between the lateral base portion members 1 0.

The lower section of the upwardly-extending portion of the mast assembly is defined by lateral channel members 1 2 and 1 3, which are spanned at their bottom ends by transverse member 14 and at their upper ends by a further transverse member 1 5.

These members together define a section of the upwardly-extending mast assembly portion which is fixed or non-displaceable in the vertical direction. However this lower section is pivotably mounted on the base members 10 by means of lugs 1 6 mounting pivot pins indicated at 1 6a in Figs. 2, 3 and 4, so that the upwardly-extending mast assembly portion can be tilted in a forward and rearward direction within predetermined limits, thereby altering the angle of the forks 9 relative to the horizontal or ground level.

The upwardly-extending mast assembly portion also has an upper section defined by substantially vertical lateral members 1 7 and 18, an upper transverse connecting member 1 9 and a lower transverse member, this upper section being displaceable in a substantially vertical direction relative to the lower section of the assembly. The upper section is guided in its vertical displacement by the inwardly directed channels of the members 1 2 and 1 3.

The forks 9 and the transverse members 20 and 21 on which they are mounted are supported or suspended from the upper transverse member 1 9 of the upper mast assembly section by means of rods or wire ropes 22. Vertical displacement of the upper mast section relative to the pivotably mounted lower section is accomplished by means of a hydraulic ram 23. The cylinder of the ram is mounted on the transverse member 14 of the lower mast section and the outer end of the piston is attached to the transverse member 1 9 of the upper mast section. Accordingly extension of the ram causes the upper mast section to be displaced in a vertical direction relative to the lower mast section, thereby raising the forks 9.

Tilting of the lower mast section relative to the base portion of the mast assembly is achieved by means of hydraulic rams 24, the piston ends of which are pivotably connected to the vertical channel members 1 2 and 1 3 of the lower mast section and the cylinders of which are pivoted to the transverse base portion member 11. Guiding of the transverse members 20 and 21 on which the forks are mounted, during vertical displacement of the forks, is achieved by means of lugs which project from the faces of those members directed away from the forks and engage within the vertical channels 1 2 and 1 3 of the lower section of the mast.This ensures that the members 20 and 21 always slide along the outer faces of the sides of the channels 1 2 and 1 3 during raising or lowering of the forks, and any tendency of the forks to swing forward away from the mast during tilting of the mast towards the rear of the trailer is prevented by engagement of the lugs in the channels.

The forward and rearward motion of the mast assembly as a whole is brought about by a further hydraulic ram 25. In this case the piston ram passes through member 11 and its outer end is attached to the transverse member 11 a of the mast assembly base portion, while the cylinder of the ram is attached to the drawbar 7 approximately one foot to the rear of the coupling 7a. Activation and control of the various rams and movements of the fork mechanism is achieved by control box 27 which is provided with suitable control valves and control levers 28. Most suitably the supply for the hydraulic equipment on the trailer is taken from the tractor hydraulic take-off, but an independent hydraulic supply for the trailer may be provided if required.However a special power unit is necessary for this or alternatively a mechanical drive to a pressure pump mounted on the trailer. The locations of the hydraulic hoses and other fittings on the trailer are not shown on the drawings. These items may be arranged on the trailer in any convenient manner.

In order to counter-act the weight of any load picked up on the forks of the trailer, especially when the forks are in their extended or outboard position, the trailer is provided with a one ton counter-weight 29, which spans the space between the channel members 2 and 3 near their leading ends.

In use, the trailer according to the invention is operated as follows. It is initially coupled to a tractor unit and the hydraulic supply from the tractor connected to the hydraulic control box 27 of the trailer. The trailer can then be backed into a position adjacent to a palletised load to be lifted. The controls 28 are operated so that ram 25 moves the fork-lift mast assembly as a complete unit to its rearmost position where the forks 9 are outboard of the axle 4 and to the rear of the ends of channel members 2 and 3 of the frame. Ram 23 is then operated to lower the upper section of the mast assembly and thereby bring the forks downwards below the level of the axle 4 and substantially to the level of the ground. The trailer is then reversed further until the forks 9 engage in the appropriate openings of the pallet to be lifted.It will be seen that the lateral spacing of the wheels 5 is such as to enable them to be disposed outwardly of the pallet. However if it is intended to use the trailer in locations where its physical size would be constrained by the existence of narrow gateways and confined yards or the like, it may be preferable to reduce the transverse spacing of the wheels and position them under the frame of the trailer. In this construction, a smaller diameter of wheel may be used. The rams 24 may be operated as required in order to tilt the upwardly extending portion of the mast assembly relative to the base portion and thus angle the forks 9 so that they can enter into the pockets of the pallet.

When it is ascertained that the forks are correctly positioned within the pockets of the pallets, the ram 23 is again operated to cause the mast upper section to be raised and thereby also to raise the forks and with them the pallet. Further tilting of the mast may be undertaken either before, during or after the actual vertical lifting operation, as required by the location and the load. When the bottom of the pallet is above the level of the upper flanges of the channel members 2 and 3, the ram 25 can be operated to retract the complete mast assembly towards the leading end of the trailer and thus bring the load inboard of the wheels. The load is therefore brought into a stable position in which it may safely be transported about the farm.The counterweight 29 prevents excessive vertical loading of the coupling 7 and any tendency to displace the rear of the tractor upwardly during the initial lift of the load, when the load is cantilevered outwardly of the rear of the trailer. During transit the load may also be lowered until at least a proportion of its weight is taken directly by the upper flanges of the channel members 2 and 3.

When the pallet load is brought to the place where the pallet is to be again put on the ground, the operations described above are repeated in reverse, the final stage in this case being the withdrawal of the forks from the pockets on the pallet and the raising of the mast upper section again to allow the forks to clear the rear end of the trailer and be brought forward into a safe and convenient transport configuration.

It will be seen that the trailer according to the invention is particularly suitable for handling the types of the palletised load which are now commonplace in farming, in particular two ton loads of bagged fertiliser. When the load has been lifted by the mast assembly and the mast assembly is moved into its retracted position, the load is in a particularly safe and convenient location for travelling, while the convenience of being able to lift the load from ground level and lower it again to ground level is also achieved. It will be seen that the disposition of the load during travelling movement is especially safe, compared with the situation where it is cantilevered out from the rear of a tractor or other unit. This also allows a reduction in the amount of counter-weighting required. In addition the forks may be moved to a retracted configuration also when the unit is running empty, a further advantageous safety feature of the trailer according to the invention.

Claims

1. A trailer for agricultural use comprising an elongate frame having wheels in the region of one longitudinal end of the frame and means for coupling the frame to a tractor unit in the region of the other longitudinal end of the frame, and a fork-lift mast assembly displaceably mounted on the frame for movement relative to the frame in the longitudinal direction of the frame between an extended position in which the forks of the mast assembly are disposed substantially rearwardly of the frame and a retracted position in which the forks are disposed substantially inboard of the trailer.

2. A trailer according to claim 1, wherein the fork-lift mast assembly has a base portion mounted on the frame by support means and said elongate frame has guide means for guiding said support means during said relative displacement of the mast assembly and frame.

3. A trailer according to claim 2, wherein the frame includes two inwardly opening channel members defining said guide means and the guide portion of the fork-lift mast assembly is mounted on the frame by rollers defining said support means and disposed within said channel members for displacement relative to the channel members in the longitudinal direction of the frame.

4. A trailer according to claim 2 or claim 3, comprising a hydraulic ram, the piston of which is coupled at its outboard end to a transverse member of the base portion of the mast assembly, and the cylinder of which is connected to a transverse member of the frame.

5. A trailer according to any of claims 2 to 4, wherein the fork-lift mast assembly has an upwardly-extending portion consisting of a first section associated with said base portion of the mast assembly and a second section displaceable relative to said first section.

6. A trailer according to claim 5, wherein said first section of the upwardly-extending portion of the fork-lift mast assembly has guide means for guiding said displaceable second section of the upwardly-extending portion of the mast assembly during said relative displacement of said first and second sections.

7. A trailer according to claim 6. wherein said first section of the upwardly-extending portion of the mast assembly includes inwardly opening channel members defining said means for guiding said section and the displaceable second section is slideable in a substantially vertical direction within these channel members.

8. A trailer according to any of claims 5 to 7, comprising a hydraulic ram, the piston of which is coupled at its outboard end to a transverse member of one of the sections of the upwardly-extending portion of the mast assembly and the cylinder of which is attached to a transverse member of the other of said sections.

9. A trailer according to any of claims 5 to 8, wherein the upwardly-extending portion of the mast assembly is pivotably associated with the base portion of the mast assembly.

10. A trailer according to claim 9. comprising one or more hydraulic rams extending between and pivotably connected to the upwardly-extending portion of the mast assembly and the base portion of the mast assembly for tilting the upwardly-extending portion relative to the base portion.

11. A trailer according to any of claims 5 to 10, wherein the forks of the mast assembly are associated with the displaceable section of the upwardly-extending portion of the mast assembly and the mast assembly includes guide means for guiding the forks during raising and lowering of the forks.

1 2. A trailer according to claim 11 when dependent on claim 7, wherein said channel members of the first section of the upwardlyextending portion of the mast assembly define said guide means for guiding the forks.

1 3. A trailer according to any preceding claim, wherein the forks are interchangeably mounted on the fork-lift mast assembly.

14. A trailer according to any preceding claim, having a counterweight in said region of the end of the frame in which the coupling means is located.

1 5. A trailer for agricultural use comprising an elongate frame having wheels at one end and means for coupling the frame to a tractor unit at the opposite elongate end of the frame, and a fork-lift mast assembly dis placeably mounted on the frame, the mast assembly being displaceable along the frame in the elongate direction of the frame between an extended position in which the forks of the mast assembly are disposed rearwardly of the rearmost portion of the frame and a retracted position in which the forks are disposed inboard of the trailer.

1 6. A trailer substantially as described herein with reference to or as illustrated in the accompanying drawings.