GB2029367A

GB2029367A - Improvements in and Relating to Materials Handling Vehicle

Info

Publication number: GB2029367A
Application number: GB7930459A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1978-09-01
Filing date: 1979-09-03
Publication date: 1980-03-19
Also published as: GB2029367B

Abstract

A loading device (2) for a trailer (1) in which there is a grab (10) such as formed from a pair of grab jaws (11) mounted at spaced apart positions on a frame (12). The frame (12) can be pivoted from a position with the grab (10) beneath the frame (12) and above a load, lying on the ground beside the trailer (1), to a position with the frame (12) on the trailer with the grab (10) and load uppermost in a balanced transporting position. <IMAGE>

Description

SPECIFICATION Improvements in and relating to Materials Handling The present invention relates to improvements in and relating to material handling devices and in particular to loading devices for trailers.

Removing felled timber from forests has always proved difficult and in particular the removal of first and second thinnings. Forests are normally planted with the trees in rows and columns, each tree being four to five feet away from its nearest neighbouring trees. The first time the forest is thinned every third row of trees is removed to provide the first thinnings. This thinning operation leaves a path of seven to nine feet, allowing for foliage, between each set of two rows of standing trees for the passage of vehicles.

Therefore any trailer or tractor used to clear the first thinnings must be narrow.

Second thinnings are removed during the second thinning operation when each alternate tree in the rows and columns is removed. Again to clear second thinnings the original path cleared during first thinning operation is used.

It is necessary to have a considerable ground clearance between any vehicle and the ground as after the first thinning operation there is a row of stumps which are relatively high. The subsequent thinning operations merely aggravate the problem. Further, it is essential that when carrying a load over such terrain that any load be centrally loaded with respect to the axles of the vehicle and that further it have a low centre of gravity. All these problems have heretofore meant that generally felled timber is removed from forests by dragging behind a tractor.

Thus, to clear these felled trees from forests the felled trees are gathered into bundles with their branches removed. Grabs are then used to draw these bundles of tree trunks out of the forests. This is a most unsatisfactory way of ciearing the felled trees.

The present invention is directed towards providing an improved materials handling device and in particular an improved loading device for use with vehicles where the terrain is generally rough.

The term "grab"in this specification includes any arrangement of loading device such as jaws, hooks and slings which may be used to grip and hold a load. The term "balanced" in relation to a trailer implies that the weight of the trailer and load is substantially evenly spread over the wheels of the trailer. In the case of a two wheeled trailer it implies that the weight of the trailer and load is substantially evenly spread over the two wheels and also evenly balanced about the trailer axle. Similarly, the term "trailer" includes any type of wheeled vehicle whether incorporating its' own power unit or not.

According to the invention there is provided a loading device for a trailer including a grab mounted on a frame said frame being mounted on the trailer for pivotal movement with the grab positioned above a load, beside the trailer, to a balanced transporting position on the trailer with the load uppermost.

The invention will be more clearly understood from the following description of some embodiments thereof, given by way of example only, with reference to the accompanying drawings, in which: Fig. 1 is a partly diagrammatic, typical sectional side elevational view of the trailer incorporating a loading device according to the invention, Fig. 2 is a partly diagrammatic, typical sectional side elevational view of the trailer incorporating a loading device of Fig. 1 showing the loading device in an alternative position, Fig. 3 is a plan view of the trailer incorporating the loading device of Fig. 1, Fig. 4 is a perspective view of the trailer of Fig.

1, Fig. 5 is a further perspective view of the trailer of Fig. 1, Fig. 6 is an end view of the loading device of the trailer of Fig. 1, Fig. 7 is a perspective view similar to Fig. 4 of an alternative embodiment of the invention, Fig. 8 is a further perspective view of the trailer of Fig. 7, Fig. 9 is an end view similar to Fig. 6 of this alternative construction of loading device, Fig. 10 is a side diagrammatic view of a means for pivoting the loading device, and Fig. 11 is a side diagrammatic view of an alternative construction of means for pivoting the loading device.

Referring to the drawings and initially to Figs. 1 to 6 thereof there is provided a trailer incorporating a loading device for transporting trse trunks indicated by the reference numerals 1 and 2 respectively. The trailer 1 is connected to a tractor 3.

The loading device 2 includes a grab 10 with a pair of grab jaws 11 pivotally mounted on a frame 12. Each grab jaw 11 in this embodiment is formed from a pair of elongated arcuately shaped grab jaws joined at their extremities by a crossmember. The frame 12 includes corner brackets 1 3 which support axles 14 on bearings, not shown. The axles 14 are rigidly connected to the grab jaws 1 Attached to the frame 12 are base bars 15, side bars 16 and end bars 17 for retaining the tree trunks. A plate 30 is mounted on the outer side of the end bars 1 7. Hydraulic rams 18, mounted between the plate 30 and levers 1 9 on the end of the axles 14, operate the grab jaws 11 independently.A shaft 20 with stub axles 21 and semi-circular pullies 22 mounted thereon is rigidly fitted to the frame 1 2 by reinforcing discs 23. The grab 10 is pivotally connected to the trailer 1 by a pair of lifting arms 24 forming portion of a sub-frame, which support the shaft 20 by the stub axles 21 in bearing (not shown The lifting arms 24 are pivotally connected to the trailer 1 as will be described below. The grab 10 is pivoted from a lifting position to a transporting position by a drive chain 25 which drives the pullies 22, as will also be described in more detail below.

The trailer 1 includes a chassis 40 formed by two side members 41 and a front cross-member 42. The chassis 40 is mounted on an axle 43 and two wheels 44. The two lifting arms 24 are pivotally connected to the chassis 40 at 46, and are rigidly joined by cross members 47 and 49 to form the sub frame. A pair of hydraulic lifting rams 48 connected between the cross member 47 and the axle 43 pivot the sub-frame from a position adjacent the trailer 1 to a raised position above the trailer 1.

The drive chains 25 pass around the pullies 22 and idler pullies 53 mounted on the front cross member 49. A drive bar 53 connects the drive chains 25. The drive bar 53 is driven by a pair of hydraulic rams 54 connected between the cross member 47 and the drive bar 53. Movement of the drive chains 25 in the direction of arrow C will cause the grab 10 to move in the direction of the arrow A from the lifting position to the loading position, see Fig. 2 and vice-versa movement of the drive chains 25 in the direction of the arrow D will cause the grab 10 to move in the direction of the arrow B, see Figs. 1 and 2.

A pair of sub-chassis members 60 are mounted below the chassis 40 and project forwardly. The trailer 1 is attached to the tractor 3 to form an integral unit by a hitch plate 61 mounted on the sub-chassis members 60 and connected by a pivot pin 62 to a receiving bracket 63 mounted on the rear of the tractor 3. The tractor-trailer uint is steered by a steering mechanism. The steering mechanism includes a pair of independently operated hydraulic steering rams 64 and 55 mounted between a plate 66 mounted on the axle 43 and steering brackets 67 mounted on the rear of the tractor 3. To steer the tractor-trailer unit to the left in the direction sf the arrow E see Fig. 3 the hydraulic ram 64 is shortened and the hydraulic ram 65 is extended.

The operation of the rams 64 and 65 is reversed to steer the tractor-trailer unit to the right.

The wheels 44 of the trailer 1 are driven by the power take off ground speed shaft (not shown) of the tractor 3 through a drive shaft 70 universal joints 71 and a differential gear box 72.

The hydraulic rams are supplied from a hydraulic pump (not shown) mounted on the tractor 3 through hydraulic hoses and hydraulic control valves (not shown). The control valves are mounted in the cab of the tractor 3.

In operation, the trailer 1 is driven rearwardly towards a load of tree trunks which have been gathered into a bundle.

The shaft 20 is raised by pivoting the lifting arms 24 upwardly to the raised position by the hydraulic lifting rams 48.

Simultaneously, the grab jaws 11 are opened by the hydraulic rams 18 as shown in Fig 4 and the grab 10 is pivoted from the transporting position as shown in Fig. 1 in the direction of the arrow B to the loading position shown in Fig. 2 so that the tree trunks are below the grab 10 and lying longitudinally with the grab 10. By pivoting the lifting arms 24 downwardly the grab 10 is lowered so that the tree trunks are within the grab 10. The grab jaws 11 are closed to embrace the tree trunks and the grab 10 is raised through 900 to stand in the vertical position. The grab jaws 11 are slightly opened to allow unevenly stacked tree trunks to fall into position so that the end of all the tree trunks rest on the end bars 1 7 and the grab jaws 11 are again closed.The grab 10 is then pivoted to the transporting position and the lifting arms 24 are pivoted downwardly through the remaining arc to lie adjacent the chassis 40.

The tree trunks are then transported while gripped in the grabs 10.

To unload the tree trunks the reverse procedure is used.

Referring to Figs. 7 to 9 there is illustrated an alternative embodiment of the invention in which parts similar to those described with reference to Figs. 1 to 6 (inclusive) are identified by the same reference numerals.

An independently operable load retaining auxiliary grab indicated generally by the reference numeral 80 comprising a pair of elongated grab jaws 81 of arcuate shape is pivotally mounted on the axle 14. Each auxiliary grab jaw 81 is connected by a link arm 82 to one end of a hydraulic ram 83 which in turn is pivotally mounted on the frame 12. The auxiliary grab jaws 81 are movable independently of or in unison with the main grab jaws 11.

In operation, the auxiliary grab jaws 81 may be arranged to move with the grab jaws 11 thus providing more support for the tree trunks.

Alternatively, when a certain load has been lifted by the greb jaws 11 and auxiliary grab jawa 81 the load may be retained in position by the auxiliary grab jaws 81 and the main grab jaws 11 used to pick up a further stack of timber. It will be readily appreciated that the advantage of using auxiliary grab jaws 81 is that the grab jaws 81 may be used to hold a small stack of timber and while the main grab jaws may be opened again to pick up further stacks of timber without having to unload the timber.

Referring to Fig. 4 there is illustrated a drive mechanism for pivoting the lifting grabs in this embodiment indicated generally by the reference numeral 90. The grabs 90 are pivotally mounted by a rotary actuator 91 on a telescopic sub-frame formed from an inner frame 92 and an outer frame 93. The inner frame 92 is moved relative to the outer frame 93 by a hydraulic ram 94. The outer frame 93 is pivotally mounted at 95 on the trailer 1. A height adjustment ram 96 is provided for the sub-frame. In operation, movement of the rotary actuator 91 causes the grabs 90 to pivot in the direction of the arrow A while the ram 94 can be operated to move the inner frame 92 outwards to the position shown by the interrupted lines in Fig. 5. This facilitates the loading of tree trunks and other similar objects. The rotary actuator 91 reverses the movement to load the trailer.

Referring to Fig. 5 the grabs 90 are in this embodiment pivotally mounted at 97 on a subframe 98 which is in turn pivotally mounted at 99 on the trailer 1. Height adjustment of the subframe 98 is provided by a hydraulic ram 100. A two part linkage is formed from an arm 101 and a bell crank lever 102 interconnected at 103. The bell crank lever 102 is pivotally mounted at 104 on the sub-frame 98 and the arm 101 is pivotally mounted at 105 on the grabs 90. A hydraulic ram 106 is mounted between the sub-frame 98 at 107 and the bell crank lever 102 at 108.

In operation, extension of the ram 1 06 causes the bell crank lever 102 to pivot in the direction of the arrow B which in turn causes the arm 101 to pivot the grabs 90 in the direction of the arrow C into the position shown by the interrupted lines.

In this embodiment of the invention with driven wheels, it is not necessary that the trailer wheels should be driven.

It will also be appreciated that the steering mechanism for the tractor-trailer unit described in the embodiment of the invention above would not be necessary if the trailer was trailed by a four wheeled tractor having two steerable wheels.

It is envisaged that the drive mechanism to pivot the grab from the loading position to the transporting position could include a hydraulic motor.

It will also be appreciated that any suitable type of grab could be used in conjunction with the trailer.

It will further be appreciated that instead of the grab being connected to the trailer by the lifting arms forming the frame the grab could be directly pivotal on the end of the trailer thus forming its own frame.

While In the embodiments of the invention described above the trailer has been used for the transportation of tree trunks it will be appreciated that the trailer could also be used for transporting many other types of loads.

Claims

1. A loading device for a trailer including a grab mounted on a frame said frame being mounted on the trailer for pivotal movement with the grab positioned above a load, beside the trailer, to a balanced transporting position on the trailer with the load uppermost.

2. A loading device as claimed in claim 1 in which the frame is pivotally mounted adjacent the rear of the trailer.

3. A loading device as claimed in claim 1 or 2 in which the grab comprises an elongated arcuately shaped grab jaw pivotally mounted on the frame and means for pivoting the jaw relative to the frame.

4. A loading device as claimed in claim 1 or 2 in which the grab comprised a pair of elongated arcuately shaped grab jaws mounted at spaced apart positions on the frame and means for pivoting each jaw relative to the frame.

5. A loading device as claimed in claim 3 or 4 in which the means for pivoting the jaw relative to the frame is a hydraulic ram.

6. A loading device as claimed in claim 4 and 5 in which the hydraulic rams are independently operable.

7. A loading device as claimed in any preceding claim in which there is a pair of grabs namely a main grab and an independently operable load retaining auxiliary grab.

8. A loading device as claimed in claim 7 comprising: a pair of spaced apart parallel axles mounted on the frame member; a main grab formed from a pair of spaced apart grab jaws rigidly mounted on each axle; a main hydraulic ram connected by a link arm to each axle for pivoting of the shaft; an auxiliary grab formed from an auxiliary grab jaw of arcuate shape pivotally mounted on one of the axles; and an auxiliary hydraulic ram mounted on the frame and connected by a link arm to the auxiliary grab jaw for pivoting of it.

9. A loading device as claimed in claim 8 in which the auxiliary grab includes a second auxiliary grab jaw mounted on the other axle and pivoted by a further auxiliary hydraulic ram.

10. A loading device as claimed in any preceding claim in which the frame is pivotally mounted on a sub-frame said sub-frame being pivotally mounted on the trailer for height adjustment relative to the trailer.

11. A loading device as claimed in claim 10 in which the sub-frame is telescopic.

1 2. A loading device as claimed in claim 10 or 11 in which the frame is pivoted relative to the sub-frame by a rotary actuator.

13. A loading device as claimed in claim 10 and 11 in which the frame is pivoted relative to the subframe by a two part linkage formed from a bell crank lever and lcver arm pivotally connected together and between the frame and the sub-frame, the bell crank lever being pivoted by a hydraulic ram.

14. A loading device as claimed in claim 10 and 11 in which the frame is pivoted relative to the sub-frame by a drive chain and pulley mounted on the frame co-axial with its pivot axis relative to the sub-frame.

1 5. A loading device as claimed in claim 14 in which the drive chain is actuated by a hydraulic motor.

16. A loading device as claimed in claim 14 in which the drive chain is actuated by a hydraulic ram.

1 7. A trailer incorporating a loading device as claimed in any of the preceding claims comprising a chassis and pair of ground engaging wheels.

18. A trailer as claimed in claim 12 in which connection means are provided to connect the trailer to a tractor.

19. A trailer as claimed in claims 17 or 18 in which the connecting means is provided by a hitch plate mounted on the trailer adapted to engage a receiving plate mounted on the rear of the tractor.

20. A trailer as claimed in any of claims 1 7 to 19 in which the ground engaging wheels are driven by the power take off ground speed shaft of the tractor through a drive shaft and differential gearbox.

21. A trailer as claimed in claims 17 to 20 in which the trailer and tractor are connected together to form an integral unit with four ground engaging wheels, a steering mechanism being fitted between the trailer and the tractor.

22. A trailer as claimed in claims 17 to 21 in which the steering mechanism is provided by a pair of independently operable and spaced apart hydraulic rams connected between the trailer and the rear of the tractor.

23. A loading device for a trailer substantially as described herein with reference to and as illustrated in Figs. 1 to 6 of the accompanying drawings.

24. A loading device for a trailer substantially as described herein with reference to and as illustrated in Figs. 7 to 9 of the accompanying drawings.

25. A loading device for a trailer substantially as described herein with reference to and as illustrated in Fig. 1 0 of the accompanying drawings.

26. A loading device for a trailer substantially as described herein with reference to and as illustrated in Fig. 11 of the accompanying drawings.