WO2010008326A1

WO2010008326A1 - Fork pallet truck

Info

Publication number: WO2010008326A1
Application number: PCT/SE2008/000455
Authority: WO
Inventors: Johnny Carlsson
Original assignee: Akromet Ab
Priority date: 2008-07-18
Filing date: 2008-07-18
Publication date: 2010-01-21

Abstract

A fork pallet truck for moving palletized goods across a supporting surface, said fork pallet truck comprising forks adapted to be inserted under the palletized goods, said forks each having a lower fork portion (6a, 6b), facing the supporting surface, and an upper fork portion (22a, 22b), which is liftable and lowerable relative to the lower fork portion, for lifting and putting down the palletized goods. According to the invention, each lower fork portion has an endless belt (17a, 17b), which is in contact with the supporting surface to support the palletized goods during its movement.

Description

Fork pallet truck

The present invention relates to a fork pallet truck for moving palletized goods across a supporting surface, said fork pallet truck comprising forks adapted to be inserted under the palletized goods, said forks each comprising a lower fork portion, facing the supporting surface, and an upper fork portion, which is liftable and lowerable relative to the lower fork portion, for lifting and putting down the palletized goods.

As used herein, fork pallet truck refers to the type of forked load handling equipment which is not based on the counterweight principle, and which sometimes also goes under the name pallet puller and pallet lift.

During the transport and delivery of palletized goods, i.e. goods loaded on pallets, a fork pallet truck is usually used to transport the palletized goods shorter distances, for example when loading and unloading.

During the distribution of goods, a fork pallet truck is usually carried in the goods transporting vehicle in order to make the loading and unloading independent of a forklift truck being available at the loading and unloading site.

Many sites where freight companies are loading and unloading palletized goods, however, lack a compacted and flat loading and unloading surface. This is a problem, since a conventional fork pallet truck runs on rollers arranged under the forks of the fork pallet truck, which rollers need to have a small diameter to allow the insertion of the forks under the pallet. On a soft, strongly sloping, uneven, gravelled or snow or grass covered supporting surface, heavy palletized goods is therefore difficult or impossible to move with a conventional fork pallet truck. In loading or unloading sites with such a supporting surface, the operator of the goods transporting vehicle is thus- dependent upon a forklift truck being available. It may happen that trucks delivering palletized goods to premises where neither a forklift truck nor a hard and flat loading and unloading surface are available are forced to carry a so-called truck-mounted forklift to ensure that the unloading can be performed. A truck-mounted forklift is a small forklift truck which can be transported hanging at the rear of the truck. A disadvantage with carrying a truck-mounted forklift, however, is that the carrying capacity of the goods vehicle decreases by the weight of the truck-mounted forklift. Furthermore, a truck-mounted forklift is an expensive and, from a technical point of view, relatively complicated vehicle, which represents a substantially more expensive investment than a fork pallet truck.

The object of the present invention is to solve the above-mentioned problems when loading and unloading palletized goods on a soft, non-compacted, uneven or sloping supporting surface, and to provide a fork pallet truck which can be used on such a supporting surface .

The fork pallet truck according to the invention is characterized in that each lower fork portion comprises an endless belt, said belts being adapted to be in contact with the supporting surface to support the palletized goods during its movement.

In the following, the invention will be described more closely with reference to the drawings, in which Figure 1 schematically shows a fork pallet truck according to the invention with the forks in a lowered position.

Figure 2 shows the fork pallet truck according to Figure 1 with the forks in a lifted position.

Figure 3 shows the fork pallet truck according to Figure 1 from below.

Figure 4 shows frame parts of the fork pallet truck according to Figure 1.

Figure 5 shows an exploded view of a lower fork portion of the fork pallet truck according to Figure 1.

Figure 6 shows the fork portion according to Figure 5 in an assembled condition.

The fork pallet truck comprises a structural frame 1. The frame 1 comprises a vertical plate 2 (see Figure 2), extending transversely to the fork pallet truck, and two vertical U-beams 3, 4, facing outward toward the sides of the fork pallet truck. At its rear long side, the left hand U-beam 3 is attached to the plate 2, at the left hand vertical side of the plate 2. In the same way, the right hand U-beam 4 is attached to the plate 2 at the right hand vertical side of the plate 2. The frame 1 also comprises a horizontal plate 5, which is attached to the lower side of the vertical plate 2 and which projects backward from the same. Like the vertical plate 2, the horizontal plate 5 extends transversely to the fork pallet truck. The frame 1 further comprises two identical, elongated and parallel, lower fork portions βa and βb, with which the above-described plate and U-beam assembly forms a rigid joint.

In the following, the lower fork portions 6a, βb will be described more closely, with reference to Figures 5 and 6. Each lower fork portion comprises a cut-out plate 8, which is bent into a U-shape such that it exhibits a horizontal top portion 9 and two parallel walls 10 and 11 pointing downwards. The plate 8 is cut such that the lower fork portion lacks a top portion at its ends, and such that the walls 10, 11 have a height at the rear end of the lower fork portion which is greater than the height of the walls 10, 11 at the front end of the lower fork portion. Each lower fork portion comprises a front inner pulley 12 and a front outer pulley 13, which are rotatably arranged between the walls 10 and 11 at the front end of the lower fork portion. Each lower fork portion also comprises a rear inner pulley 14 and a rear outer pulley 15, which are rotatably arranged between the walls 10 and 11 at the rear end of the lower fork portion. Each lower fork portion further comprises four support rollers 16, which are rotatably arranged between the walls 10 and 11. The support rollers 16 are disposed at equal mutual distances in line with the inner pulleys 12 and 14. The inner pulleys 12, 14 and the support rollers 16 are arranged such that their lower portions project about 2 cm below the lower edges of the walls 10 and 11.

Each lower fork portion comprises an endless belt 17 of rubber. The belt 17 runs in a loop around the inner pulleys 12, 14. Accordingly, in the length and cross direction, the belt 17 has an extension which, on the whole, corresponds to the extension of the lower fork portion. The front outer pulley 13 is arranged outside the loop of the belt 17, immediately behind the front inner pulley 12. The pulley 13 is arranged in contact with the belt 17 and causes the belt 17 to encircle the pulley 12 approx. 220°, i.e. more than 180°. In the same way, the rear outer pulley 15 is arranged outside the loop of the belt 17 immediately in front of the rear inner pulley 14, but in contact with the belt 17, and causes the belt 17 to encircle the pulley 14 approx. 240°, i.e. more than 180°. The support rollers 16 are arranged inside the loop of the belt 17. The lower portions of the support rollers 16 are in contact with the belt 17 and support the belt 17 in its straight course between the lower portions of the inner pulleys 12 and 14. Preferably, at least one of the positions of the outer pulleys 13 and 15 is adjustable to enable tensioning or loosening of the belt 17.

As is evident from Figures 1, 2 and 4, the U-beams 3, 4 are attached to the outwardly facing walls 10a and lib, and the horizontal plate 5 is attached to the rear ends of the lower fork portions 6a and 6b. In other words, the plate 5 is arranged above the rear inner pulleys 14a and 14b. Two electric motors 18a, 18b are mounted on the upper side of the plate 5. The left hand electric motor 18a is arranged to drive the rear inner pulley 14a of the left hand lower fork portion 6a, and in the same way, the right hand electric motor 18b is arranged to drive the rear inner pulley 14b of the right hand lower fork portion 6b. The driving takes place by means of drive belts 19a, 19b, which run between the axles of the respective pair of electric motor/pulley through openings in the plate 5. The fork pallet truck also comprises a portion 20 which is liftable and lowerable relative to the frame 1. The portion 20 comprises a cover 21, which covers the above-mentioned plates 2 and 5 and the U-beams 3, 4. The portion 20 also comprises two identical, elongated and parallel, upper fork portions 22a and 22b, which project above the lower fork portions βa, 6b. The cover 21 is rigidly attached to the upper fork portions 22a, 22b. The fork pallet truck comprises a lifting device in the form of a hydraulic piston 23, which is arranged between the frame 1 and the portion 20, for lifting and lowering the upper fork portions 22a, 22b relative to the lower fork portions βa, βb. For each U-beam 3, 4, the portion 20 comprises two wheels 24, which are arranged to travel in the U-beam during the lifting and lowering movement, to only allow the portion 20 freedom of movement in a vertical direction.

The upper fork portions 22a, 22b are liftable and lowerable between a lower end position, shown in Figure 1, and an upper end position, shown in Figure 2. In the lower end position, the upper fork portions 22a, 22b rest upon the lower fork portions 6a, βb. As is evident from Figure 3, the upper fork portions 22a, 22b extend slightly further to the front that the lower fork portions 6a, 6b, and are bevelled at the front in order to facilitate the insertion of the forks under a pallet. On their bottom side, the upper fork portions 22a, 22b exhibit a recess, which enables the upper fork portions 22, 22b to substantially enclose the lower fork portions 6a, 6b in the lower end position. Accordingly, the lower fork portions 6a, 6b and the upper fork portions 22a, 22b together constitute the forks of the fork pallet truck. In the lower end position, each fork has a height allowing the insertion of the forks under a pallet. In the upper end position, the height of the forks is sufficient to lift the pallet from the supporting surface so that the palletized goods is supported completely by the belts 17a and 17b.

The fork pallet truck comprises a control handle 25, by means of which an operator controls the fork pallet truck from a position at the side of, or behind, the fork pallet truck. By means of the control handle 25, the operator can bring the upper fork portions 22a, 22b from the lower end position to the upper end position by moving the control handle 25 up and down in a pumping movement, in a conventional way, wherein hydraulic oil is caused to flow to the hydraulic piston 23 in order to lift the portion 20 with associated upper fork portions 22a, 22b. To lower the upper fork portions 22a, 22b, the operator releases a latch (not shown) , in a known way, wherein hydraulic oil is allowed to flow out of the hydraulic cylinder in order to lower the portion 20 with associated fork portions 22a, 22b. Alternatively, the lifting and lowering movement can be driven.

The control handle 25 also comprises controls (not shown) by means of which the operator can control the electric motors 18a, 18a, and thereby the operation of the belts

17a, 17b. By means of the controls, the operator can thus individually control the rotational direction and rotational speed of the belts 17a, 17b. The operator can control the electric motors 18a, 18b independently of each other, whereby the operator can turn the fork pallet truck by making the belts 17a, 17b move at different speeds. The operator can also turn the fork pallet truck on the spot by making the belts 17a, 17b rotate in different directions, one belt forwards and the other belt backwards. To steer the fork pallet truck during movement, the operator moves the control handle 25 in a lateral direction. The deflection of the control handle 25 in the lateral direction is registered by a sensor (not shown) , which sends signals to the electric motors 18a, 18b to cause the belts 17a, 17b to move at different speeds, whereby the fork pallet truck is caused to follow the direction of the control handle 25 through the agency of the belts 17a, 17b. Accordingly, the fork pallet truck is steered according to the same principle as in a caterpillar drive, i.e. by causing the belts 17a, 17b to move at different speeds in a controlled way.

To facilitate the manoeuvring of the fork pallet truck in cramped spaces, e.g. on a platform body of a truck when the fork pallet truck is to be stowed away before transport, the fork pallet truck comprises a folding, and freely pivotable, auxiliary wheel 26. The auxiliary wheel 26 is placed between the belts 17a, 17b at the rear end of the truck, and can be folded down from an upper position above the level of the belts 17a, 17b to a lower position below the level of the belts 17a, 17b by means of a hydraulic piston 27. The control of the hydraulic piston 27 takes place by means of a foot actuated hydraulic pump (not shown) , by means of which the operator can lift up the rear end of the fork pallet truck so that the belts 17a, 17b at the rear end of the fork pallet truck clear the supporting surface. When the auxiliary wheel 26 is in the lower position, it is only the auxiliary wheel 26 and the belts 17a, 17b at the front inner pulleys 12a, 12b which are in contact with the supporting surface. Since the auxiliary wheel is freely pivotable, the operator can easily push the rear end of the fork pallet truck in a lateral direction, i.e. transversely to the length direction of the belts 17a, 17b, for example in order to park the fork pallet truck next to a wall. It is appreciated that the auxiliary wheel 26 is only intended to be used on a flat and hard supporting surface, for example on a platform body of a truck, and only when the fork pallet truck has no load.

The fork pallet truck is approx. 145 cm long, approx. 55 cm wide, and approx. 55 cm high. The length of the forks is approx. 115 cm, and the height of the forks above the supporting surface is approx. 8.5 cm in the lowermost position and approx. 20 cm in the uppermost position. In each lower fork portion 6a, 6b, the diameter of the front inner pulley 12 is approx. 7 cm, the diameter of the rear inner pulley 14 approx. 15 cm, and the diameter of the support rollers 16 approx. 5 cm. The diameter of the auxiliary wheel is approx. 18 cm.

In the foregoing, the invention has been described starting from a specific embodiment. It is appreciated, however, that other embodiments and variants are possible within the scope of the invention. For instance, instead of two motors (one motor per belt) , the fork pallet truck can be equipped with only one motor, which drives both belts via two separate and individually controllable gear systems. It is also appreciated that the fork pallet truck, as an alternative or complement to the control handle, can comprise a remote control unit, by means of which the operator can send signals to actuators onboard the fork pallet truck for controlling the electric motors 18a, 18b and the hydraulic pistons 23, 27. The communication between the remote control unit and the actuators can take place by wire or wirelessly.

Claims

C L A I M S

1. A fork pallet truck for moving goods loaded on a pallet across a supporting surface, said fork pallet truck comprising forks, each comprising a lower fork portion (6a, 6b), facing the supporting surface, and an upper fork portion (22a, 22b) , which projects above and is liftable and lowerable relative to the lower fork portion (6a, 6b) between a lower end position allowing insertion of the forks under the pallet, and an upper end position being sufficient to lift the pallet from the supporting surface, characterized in that each lower fork portion (6a, 6b) comprises an endless belt (17, 17a, 17b) which has an extension in the transverse direction of the fork pallet truck which, on the whole, corresponds to the extension of the lower fork portion (6a, 6b), said belts (17, 17a, 17b) being arranged to be in contact with the supporting surface to support the palletized goods during its movement.

2. The fork pallet truck according to claim 1, characterized in that the belt (17, 17a, 17b) of each lower fork portion (6a, 6b) runs between a front pulley (12, 12a, 12b), which is arranged in the front end of the lower fork portion (6a, 6b), and a rear pulley (14, 14a, 14b) , which is arranged in the rear end of the lower fork portion ( 6a, 6b) .

3. The fork pallet truck according to claim 2, characterized in that each lower fork portion (6a, 6b) comprises a plurality of support rollers (16), which are arranged inside the loop of the belt (17, 17a, 17b) between said pulleys (12, 12a, 12b; 14, 14a, 14b) to support the belt (17, 17a, 17b) in its course.

4. The fork pallet truck according to any one of the claims 1-3, characterized in that each belt (17a, 17b) is driven by a motor (18a, 18b) .

5. The fork pallet truck according to any one of the claims 1-3, characterized in that each belt (17a, 17b) is driven by a motor (18a, 18b) of its own.

6. The fork pallet truck according to any one of the claims 4 and 5, characterized in that the driving of the belt (17a, 17b) takes place by means of the motor (18a, 18b) driving the axle of said rear pulley (14a, 14b) .

7. The fork pallet truck according to any one of the claims 1-6, characterized in that the fork pallet truck is steered with a caterpillar drive.

8. The fork pallet truck according to any one of the claims 1-7, characterized in that it comprises an auxiliary wheel (26) , which can be folded down to lift the fork pallet truck so that portions of the belts (17a, 17b) clear the supporting surface.

9. The fork pallet truck according to any one of the claims 1-8, characterized in that the belts (17a, 17b) extend along the major part of the length of the fork pallet truck.

10. The fork pallet truck according to any one of the claims 1-9, characterized in that the belts (17a, 17b) are adapted to support the palletized goods.