WO2008129447A1

WO2008129447A1 - A fork lift

Info

Publication number: WO2008129447A1
Application number: PCT/IB2008/051410
Authority: WO
Inventors: Frederick Christiaan Aggenbacht
Original assignee: Individual
Current assignee: Individual
Priority date: 2007-04-18
Filing date: 2008-04-14
Publication date: 2008-10-30
Anticipated expiration: 2009-10-18
Also published as: WO2008129447A8

Abstract

The invention relates to a fork lift (10, 200) and to a vehicle (102). The fork lift (10, 200) includes a chassis (12), a plurality of wheels (14, 16, 207, 208) which are rotatably mounted to the chassis (12), and an upwardly extending or extendable lifting column (18) which is engaged with, and slidingly displaceable relatively to, the chassis (12). The fork lift (10, 200) further includes a lifting formation (20) which includes an abutment bracket (22), which is displaceably engaged with the column (18), and which includes a pair of elongate bars or tines (24) which project from the abutment bracket (22).

Description

A FORK LIFT

BACKGROUND OF THE INVENTION

The invention relates to a fork lift for use in the stacking of products and the unloading of vehicles.

The Inventor is aware that some transport vehicles have fork lifts mounted thereto for use at a loading or unloading site. For stability, known fork lifts have counter weights or ballasts to compensate for the load carried by the fork lift. This causes the fork lift to be heavy, makes storage and transport of the fork lift difficult and reduces the carrying capacity of the transport vehicle. The Inventor seeks an alternative fork lift which might alleviate some of the aforementioned problems.

SUMMARY OF THE INVENTION

Accordingly, the invention provides a fork lift which includes: a chassis; a plurality of wheels which are rotatably mounted to the chassis; an upwardly extending or extendable lifting column which is engaged with, and slidingly displaceable relatively to, the chassis; and a lifting formation which includes an abutment bracket, which is displaceably engaged with the column, and which includes a pair of elongate bars or tines which project from the abutment bracket.

The chassis may include a pair of spaced apart chassis tracks with which the column is displaceably engaged.

The wheels may include at least one caster wheel which is swivelably mounted to the chassis.

The column may include a plurality of column rollers which are engaged or engageable with the chassis. The column may include a pair of spaced apart primary pillars. Each primary pillar may include a pillar track with which the lifting formation is displaceably engaged.

The column may include at least one primary lifting arrangement.

The primary lifting arrangement may include: a flexible, elongate tie member which extends between a first end which is fixed to the primary pillar and a second end which is fixed to the lifting formation; a primary pulley over which the tie member runs; and a primary hydraulic cylinder which is connected to the primary pulley and which is operable to displace the pulley, thereby to displace the lifting formation relative to the primary pillars.

The column may include a secondary pillar. The column in such case may include a secondary lifting arrangement. The secondary lifting arrangement may include a plurality of rollers which are displaceably engaged with the column.

Each of the bars may be displaceable relative to its associated abutment bracket. Each of the bars may include a free end and a runner formation which is pivotally attached at or towards the free end. Each bar may include an actuator which is connected to the runner formation and which is configured to displace the runner between a retracted position and an extended position. The actuator may include a pivot cylinder which acts between the bar and the runner formation.

The fork lift may include a primary drive unit and the wheels may include at least one drive wheel coupled to the primary drive unit. The primary drive unit may include a motor. The primary drive unit may include a hydraulics motor and a battery pack.

The fork lift may include a secondary drive unit which acts directly on the drive wheel. The secondary drive unit may include a servo motor and a reduction gear box. The fork lift may include a column drive unit which acts between the chassis and the column.

The column drive unit may include: a pinion which is rotateably mounted to the column; and a toothed rack which is fixed to the chassis and with which, in use, the pinion meshes.

The column drive unit may include a drive motor which is fixed relative to the column and which drives the pinion.

The fork lift may include a seat which is attached to the column and controls which are attached to the column.

Instead, the fork lift may include a tiller head projecting from the chassis for steering the fork lift.

The fork lift may be collapsible. The lifting column may is pivotable relative to the chassis between an operative condition in which the lifting column projects upwardly from the chassis and a storage condition in which the lifting column is recumbent relative to the chassis. The fork lift may include a pivot cylinder between the lifting column and the chassis, the pivot cylinder being operable to displace the lifting column between its operative condition and its storage condition.

The invention extends to a vehicle which includes a chassis which defines a cavity therein or therebeneath shaped and dimensioned to accommodate therein a collapsed fork as defined above.

The vehicle may accordingly include the collapsed fork lift dismountably accommodated within the cavity.

The invention extends further to a vehicle which includes a fork lift as defined above, dismountably mounted thereto. BRIEF DESCRIPTION OF THE DRAWINGS

The invention is further described, by way of an example, with reference to the accompanying drawings.

In the drawings:

Figure 1 is a three-dimensional view of a fork lift in accordance with the invention; Figures 2 and 3 are side views of the fork lift of Figure 1 in use; Figure 4 is a view from above of the fork lift of Figure 1 in use; Figure 5 is a view from above of the fork lift of Figure 1 with certain components removed for illustration;

Figure 6 is a sectional side view of a lifting column of the fork lift of Figure 1 ; Figure 7 is a different sectioned side view of the lifting column and of a secondary pillar of the fork lift of Figure 1 ; Figure 8 is a three-dimensional view of another embodiment of a fork lift in accordance with the invention;

Figure 9 is a view from above of the fork lift of Figure 8 in a storage condition; Figure 10 is a side view of the fork lift of Figure 8 in a storage condition; Figure 1 1 is a three-dimensional view of the fork lift of Figure 8 in a storage condition;

Figure 12 is a side view of part of a vehicle and the fork lift of Figure 8 in a storage condition mounted to the vehicle; and

Figure 13 is a side view of the full vehicle of Figure 12.

DESCRIPTION OF PREFERRED EMBODIMENTS

Figures 1 to 5 illustrate a fork lift 10 which has a U-shaped, operatively horizontally extending chassis 12, a set of drive wheels 14 which are rotatably mounted to the chassis 10, and a free riding caster wheel 16 which is swivelably mounted to the chassis 12. The fork lift 10 has an operatively upwardly extending lifting column 18 which is engaged with, and slidingly displaceable relative to, the chassis 12. The fork lift 10 further has a lifting formation or bracket 20 which has an abutment bracket 22 which is displaceably engaged with the column 18 and a pair of elongate bars or tines 24 which project from the abutment bracket 22. The chassis 12, column 18 and lifting bracket 20 are made from appropriate metal materials.

The chassis 12 has a pair of spaced apart and opposing chassis tracks or channels 26 with which the column 18 is displaceably engaged. Each of the chassis channels 26 are made from U-shaped channel iron.

A power pack 28 is fitted to the chassis 12. The power pack 28 has a primary drive unit which can be in the form of any appropriate petrol, diesel or electrical motor. The power pack 28 can additionally have a battery pack and/or a hydraulic generator to provide hydraulic fluid supply.

The drive wheels 14 and caster wheel 16 are known. At least one or each of the drive wheels 14 is connected to an appropriate servo motor 30. Power to the servo motors 30 is supplied from the power pack 28 and, if desired, a reduction gearbox 32 can be fitted between each servo motor 30 and drive wheel 14. The servo motors 30 and gearboxes 32 are known.

The column 18 has two opposing base plates 34 and a pair of spaced apart and upwardly projecting primary pillars 36, each of which extends from a base plate 34. The column has a central secondary pillar 38 which projects upwardly between the primary pillars 36 and which is attached to each of the primary pillars 36 by way of cross bracing 40.

The primary pillars 36 and the secondary pillar 38 are pivotally attached to the base plates 34 such that the column 18 can be pivotally displaced relative to the chassis 12 thereby to collapse the fork lift. More particularly, the fork lift 10 is displaceable between an operative condition in which the column 18 projects transversely from the chassis 12 and a storage condition in which the column 18 is recumbent relative to the chassis 12 (see further below). A hydraulic, pivot cylinder 41 acts between each base plate 34 and each primary pillar 36 and is used to pivot the primary pillars 36 and the secondary pillar 38 relatively to the base plates 34 and chassis 12. Two column rollers 42 are attached to each base plate 34 and each set of column rollers 42 runs in one of the chassis channels 26. In this manner the column 18 is horizontally movable relatively to the chassis 12. A column drive unit 44 acts between the column 18 and the chassis 12 at each base plate 34. Each of the column drive units 44 has a second servo motor 46 which drives a pinion 48. The second servo motor 46 is fixed to the base plate 34 and to the column 18 and the pinion 48 is rotatably connected to the column 18 through the second servo motor 46. The pinion

48 is meshed with an elongate, toothed rack 49 which is fixed to a respective chassis channel 26 and the chassis 12.

Each of the primary pillars 36 has a vertically extending pillar channel 52 with which the lifting bracket 20 is displaceably engaged. Adjacent each of the primary pillars 36 is a primary lifting arrangement 54 which acts between the primary pillar 36 of the column 18 and the lifting bracket 20.

As is illustrated in Figure 6, each of the primary lifting arrangements 54 has a flexible, elongate tie member 56 which extends from a first end 58 which is fixed to the primary pillar 36 to a second end 60 which is fixed to the lifting bracket 20. In this example, the tie member 56 is in the form of a cable but could alternatively be in the form of a rope or chain. The tie member 56 runs over a primary pulley 62. The primary pulley 62 is attached to a piston 64 which extends from a hydraulic sleeve 66 and is movable relatively to the primary pillar 36. The piston 64 and sleeve 66 form part of a primary hydraulic cylinder 67. The sleeve 66 is fixed to the column 18. Although two primary lifting arrangements 54 are shown in this example a single primary lifting arrangement may be sufficient in certain applications.

A secondary lifting arrangement 68 is positioned in the secondary pillar 38. As is shown in Figure 7, the secondary lifting arrangement 68 has a tie member 70 (which is similar to the tie member 56) and a plurality of secondary pulleys 72 over which the tie member 70 runs. A first secondary pulley 72A is fixed to an upper side 74 of the secondary pillar 38, a second secondary pulley 72B is fixed to a lower side 76 of the secondary pillar 38 and a third secondary pulley 72C is attached to a piston 78 which extends from a hydraulic sleeve 80. The piston 78 and sleeve 80 form part of a secondary hydraulic cylinder 81 . The hydraulic sleeve 80 is fixed to the secondary pillar 38 and the third secondary pulley 72C is movable relatively to the secondary pillar 38. A first end 82 of the tie member 70 is attached to the secondary pillar 38 and the opposite, second end 84 of the tie member 70 is fixed to the lifting bracket 20. From the first end 82 the tie member 70 passes under the third secondary pulley 72C, over the first secondary pulley 72A, under the second secondary pulley 72B and to the second end 84.

The abutment bracket 22 has two sets of opposing bracket rollers 86 which are trapped and run inside the opposing pillar channels 52 of the primary pillars 36.

In this example, the tines 24 are fixed to the abutment bracket 22. It is however possible to attach each of the tines 24 to the abutment bracket 22 in a manner to allow sideways movement of each of the tines 24 relative to the abutment bracket 22 in order to adjust the spacing between the tines 24.

Each of the tines 24 has a free end 90 which is tapered. At the free end 90, each of the tines 24 has a roller or runner 92 which is pivotally attached to the tine 24. The runner 92 is connected to an actuator in the form of a hydraulic, roller cylinder 94 which is positioned in and fixed to the tine 24. The roller cylinder 94 causes pivotal movement of the runner 92 relatively to the tine 24 and causes the runner 92 to be displaced between a retracted and an extended position (i.e. towards or away from the tine 24).

A seat 96 is fixed to the column 18. Alternatively, the seat 96 can be attached to the chassis 12. Controls 98 are positioned in front of the seat 96 and are connected to the power pack 28, first servo motors 30, drive units 44, pivot cylinders 40, roller cylinders 94, primary hydraulic cylinders 67 and the secondary hydraulic cylinder 81 . An operator (not shown) sits on the seat 96 and controls the operation of the fork lift 10 by way of the controls 98.

Although the fork lift 10 is described with reference to servo motors and hydraulic cylinders it is important to understand that the servo motors can be replaced with appropriate hydraulic or pneumatic drive motors and the hydraulic cylinders with appropriate drives on each of the ties 56, 70.

In use, and as is shown in Figures 2, 3 and 4, the tines 24 are inserted into a pallet 100 on a transport vehicle 102. The pallet 100 carries a load 104 of any appropriate kind. By actuating the roller cylinders 94 the runners 92 are pivoted away from the tines 24. As the runners 92 contact a load bed 106 of the vehicle 102 the pallet 100 is lifted from the load bed 106 by the tines 24. The weight of the load 104 is carried by the runners 92 and the wheels 14, chassis 12, column 18 and lifting bracket 20 of the fork lift 10. Importantly there is no counter ballast for the load 104 on the fork lift 10.

In order to remove the pallet 100 and load 104 from the load bed 106 the drive units 44 are activated to cause relative movement between the column 18 and the chassis 12 as the column rollers 42 run in the chassis channels 26. The column 18 moves towards a rear 108 of the chassis 12 until a centre of gravity of the fork lift 10 is rearward of the foremost support formation of the fork lift (i.e. the drive wheels 14). As the column 18 moves towards the rear 108 of the chassis 12, the pallet 100 and load 104 are pulled from the load bed 106 while the runners 92 run on the load bed 106. Once the centre of gravity of the fork lift 10 has passed behind the drive wheels 14, the pallet 100 and load 104 can be completely removed from the vehicle 102.

Depending on requirements, the column 18 can be pivoted relatively to the chassis 12 by way of the pivot cylinders 47. The lifting bracket 20 is raised or lowered by actuating the primary cylinders 67. As the pistons 64 are drawn into the sleeves 66, the lifting bracket 20 is lowered and as the pistons 64 are extended from the sleeves 66 the lifting bracket 20 is raised. As the ties 56 are each looped over the first pulley 62, small movements of the pistons 64 are amplified in the lifting bracket 20. The bracket rollers 86 ensure smooth up and down movement of the lifting bracket 20 relatively to the primary pillars 36. Movement of the fork lift 10 is controlled by the simultaneous or independent activation of the drive wheels 14 to cause forward, reverse and turning motions of the fork lift 10. In order to release the pallet 100 and load 104, the fork lift 10 is brought adjacent the required loading surface and the runners 92 are brought into contact with the loading surface. While the runners 92 remain in contact with the loading surface, the column 18 is moved forward on the chassis 12 away from the rear 108 until the pallet 100 and load 104 are clear of the chassis 12. In this position, the runners 92 are retracted by way of the roller cylinders 94 and the tines 24 are withdrawn either by moving the fork lift 10 away from the pallet 100 and load 104 or by moving the column 18 towards the rear 108 of the chassis 12.

It is important to understand that the fork lift 10 can load and unload the pallet

100 and load 104 without the requirement of a counter ballast. This allows for a light weight construction of the fork lift 10 and reduces power requirements. The omission of the ballast is as a result of the relative movement of the column 18 on the chassis 12 and the action of the runners 92.

During normal use of the fork lift 10, the secondary lifting arrangement 68 is passive and free movement of the piston 78 relatively to the sleeve 80 is allowed. For transport purposes, the fork lift 10 can hoist itself onto the back of the vehicle 102. In order to do this, the tines 24 are inserted into appropriate slots on the vehicle 102, the primary lifting arrangements 54 are disabled and the secondary lifting arrangement 68 is activated. As the piston 78 is pulled into the sleeve 80, relative movement between the lifting bracket 20, column 18 and chassis 12 is caused. As the tines 24 are trapped on the vehicle 102 the column 18 and chassis 12 are lifted from the ground until the chassis 12 is at an appropriate height above a surface 1 10. In this position the lifting bracket 20 is locked to the column 18 and chassis 12 in any appropriate manner and the fork lift 20 is ready for transport.

Figures 8 to 13 illustrate another embodiment of a fork lift 200 in accordance with the invention. Those parts in Figures 8 to 13 which are the same or similar to those of Figures 1 to 7 are denoted by the same reference numerals. Unless otherwise indicated, the fork lift 200 also operates in the same or similar fashion as the fork lift 10.

A notable difference of the fork lift 200 compared to the fork lift 10 is the addition of a tiller head 202 in instead of the seat 96 and associated controls 98. The tiller head 202 includes a handle 204 at a free end thereof to be grasped by the fork lift operator. The tiller head 202 may include associated controls (not illustrated) proximate the handle 204.

The tiller head 202 is detachably fastened to a primary drive unit 206 which is swivelably mounted to the chassis 12. The drive unit 206 includes a single drive wheel 207 (refer to Figure 10) for propelling the fork lift 200. The fork lift 200 correspondingly includes two passive front wheels 208 mounted to the chassis 12 to rotate about a generally recumbent axis but not about a generally upright axis (the wheels 208 are thus not castor wheels like those wheels 16 of the fork lift 10). The configuration of the front wheels 208 eliminates any twisting effect on the chassis 12.

The drive wheel 207 is rotatably mounted to the drive unit 206 and, because the drive unit 206 is swivelable by means of the tiller head 202, the drive wheel 207 acts as a castor wheel for steering the fork lift 200. The illustrated fork lift 200 is thus a walk- behind type fork lift steerable by the fork lift operator rudder-fashion.

Figures 9 to 13 illustrate the fork lift 200 collapsed into its storage condition. To achieve this collapsibility, the lifting bracket 20 is arranged to pivot through an angle of 270° about its pivot axis 20.1 . In other words, the lifting bracket 20 is pivotable above and over the lifting column 18 so that the tines 24 lie generally adjacent and parallel therewith. Further, the lifting column 18 is also pivotable about its pivot axis 18.1 by 90° to lie generally parallel with the chassis 12. The pivoting of the lifting formation 20 can be either manual (i.e. by means of the fork lift operator) or by means of a drive unit (not illustrated). The pivoting of the lifting column 18 is achieved by means of the pivot cylinders 41 .

Thus, comparing Figure 8 to Figure 1 1 , the lifting formation 20 and the lifting column 18 can be pivoted about their respective pivot axes 20.1 , 18.1 so that the tines 24 and the lifting column 18 lie generally parallel with the chassis 12. The fork lift 200 in this collapsed, storage condition has a generally flat or low profile. The tiller head 202 can be detached so as not to obstruct storage of the fork lift 200. Referring now to Figures 12 and 13, the fork lift 200 in its storage condition can be accommodated within a cavity 1 12 defined beneath or within a chassis 1 10 of the vehicle 102. The cavity 1 12 can conveniently be defined intermediate ends of the vehicle 102 (e.g. between fore and aft wheel arrangements of the vehicle), and therefore storage and transport of the fork lift 200 need not increase the overall length of the vehicle 102.

Again it is important to note that as the fork lift 10, 200 has no ballast to compensate for the load 104 it is relatively lightweight and can therefore be stored and transported in the manner described.

Claims

CLAIMS:

1 . A fork lift which includes: a chassis; a plurality of wheels which are rotatably mounted to the chassis; an upwardly extending or extendable lifting column which is engaged with, and slidingly displaceable relatively to, the chassis; and a lifting formation which includes an abutment bracket, which is displaceably engaged with the column, and which includes a pair of elongate bars or tines which project from the abutment bracket.

2. A fork lift as claimed in claim 1 , in which the chassis includes a pair of spaced apart chassis tracks with which the column is displaceably engaged.

3. A fork lift as claimed in any of the preceding claims, in which the wheels include at least one caster wheel which is swivelably mounted to the chassis.

4. A fork lift as claimed in any of the preceding claims, in which the column includes a plurality of column rollers which are engaged or engageable with the chassis.

5. A fork lift as claimed in any of the preceding claims, in which the column includes a pair of spaced apart primary pillars.

6. A fork lift as claimed in claim 5, in which each primary pillar includes a pillar track with which the lifting formation is displaceably engaged.

7. A fork lift as claimed in claim 5 or claim 6, in which the column includes at least one primary lifting arrangement.

8. A fork lift as claimed in claim 7, in which the primary lifting arrangement includes: a flexible, elongate tie member which extends between a first end which is fixed to the primary pillar and a second end which is fixed to the lifting formation; a primary pulley over which the tie member runs; and a primary hydraulic cylinder which is connected to the primary pulley and which is operable to displace the pulley, thereby to displace the lifting formation relative to the primary pillars.

9. A fork lift as claimed in any of claims 5 to 8 inclusive, in which the column includes a secondary pillar.

10. A fork lift as claimed in claim 9, in which the column include a secondary lifting arrangement.

1 1 . A fork lift as claimed in claim 10, in which the secondary lifting arrangement includes a plurality of rollers which are displaceably engaged with the column.

12. A fork lift as claimed in any of the preceding claims, in which each of the bars is displaceable relative to its associated abutment bracket.

13. A fork lift as claimed in any of the preceding claims, in which each of the bars includes a free end and a runner formation which is pivotally attached at or towards the free end.

14. A fork lift as claimed in claim 13, in which each bar includes an actuator which is connected to the runner formation and which is configured to displace the runner between a retracted position and an extended position.

15. A fork lift as claimed in claim 14, in which the actuator includes a pivot cylinder which acts between the bar and the runner formation.

16. A fork lift as claimed in any of the preceding claims, which includes a primary drive unit and in which the wheels include at least one drive wheel coupled to the primary drive unit.

17. A fork lift as claimed in claim 16, in which the primary drive unit includes a motor.

18. A fork lift as claimed in claim 16 or claim 17, in which the primary drive unit includes a hydraulics motor and a battery pack.

19. A fork lift as claimed in any of claims 16 to 18 inclusive, which includes a secondary drive unit which acts directly on the drive wheel.

20. A fork lift as claimed in claim 19, in which the secondary drive unit includes a servo motor and a reduction gear box.

21 . A fork lift as claimed in any of the preceding claims, which includes a column drive unit which acts between the chassis and the column.

22. A fork lift as claimed in claim 21 , in which the column drive unit includes: a pinion which is rotateably mounted to the column; and a toothed rack which is fixed to the chassis and with which, in use, the pinion meshes.

23. A fork lift as claimed in claim 22, in which the column drive unit includes a drive motor which is fixed relative to the column and which drives the pinion.

24. A fork lift as claimed in any of the preceding claims, which includes a seat which is attached to the column and controls which are attached to the column.

25. A fork lift as claimed in any of claims 1 to 23 inclusive, which includes a tiller head projecting from the chassis for steering the fork lift.

26. A fork lift as claimed in any preceding claims, which is collapsible.

27. A fork lift as claimed in claim 26, in which the lifting column is pivotable relative to the chassis between an operative condition in which the lifting column projects upwardly from the chassis and a storage condition in which the lifting column is recumbent relative to the chassis.

28. A fork lift as claimed in claim 27, which includes a pivot cylinder between the lifting column and the chassis, the pivot cylinder being operable to displace the lifting column between its operative condition and its storage condition.

29. A vehicle which includes a chassis which defines a cavity therein or therebeneath shaped and dimensioned to accommodate therein a collapsed fork lift as claimed in any of claims 26 to 28 inclusive.

30. A vehicle as claimed in claim 29, which includes the collapsed fork lift dismountably accommodated within the cavity.

31 . A vehicle which includes a fork lift as claimed in any of the preceding claims, dismountably mounted thereto.