GB2244041A

GB2244041A - Load handling apparatus

Info

Publication number: GB2244041A
Application number: GB9110849A
Authority: GB
Inventors: Noel Robert James Kelly
Original assignee: K D TRUCKS Ltd
Current assignee: K D TRUCKS Ltd
Priority date: 1990-05-18
Filing date: 1991-05-20
Publication date: 1991-11-20
Anticipated expiration: 2011-05-20
Also published as: GB2244041B; GB9110849D0

Abstract

A load handling apparatus for mounting on a structure comprises first and second pivotally connected booms (10, 12). The first boom (10) is for pivotal mounting on the structure and the second boom (12) mounts an attachment carrier (18). Means for controlling movement of the booms (10, 12) comprises a first hydraulic ram and cylinder (20) connected between the structure and first boom (10), second and third hydraulic ram and cylinders (26, 28) connected between the two booms (10, 12), a fourth hydraulic ram and cylinder (34) connected near to the pivotal connection (14) of the two booms (10, 12) and a fifth hydraulic ram and cylinder (40) connected between the second boom (12) and the carrier (18). A sixth hydraulic ram and cylinder (50) is provided between the first boom (10) and the structure. A swing plate (54) is mounted on the first boom (10) adjacent to the pivotal connection (14). The arrangement maintains the attitude of the carrier (18). <IMAGE>

Description

LOAD HANDLING APPARATUS.

This invention relates to a load handling apparatus particularly, but not necessarily, for mounting on a wheeled vehicle. Load handling apparatus of the type with which this invention is primarily concerned has been proposed heretofore comprising a telescopic boom arrangement with the outer end mounting an attachment carrier.

A disadvantage of such apparatus is that there is no automatic self-leveling arrangement of the carrier, and hence of an attachment carried thereon as the boom is telescoped forwardly at all lift heights. With a telescopic boom arrangement, to lift and place an attachment carrier and any load thereon, an operator has to manipulate simultaneously two or more levers governing operation of a forward reach and a lift hydraulic ram and cylinder arrangements. This is a highly skilled task for an operator and is prone to mishaps.

An object of the present invention is to obviate or mitigate the aforesaid disadvantage.

Accordingly, the present invention is a load handling apparatus for mounting on a structure comprising first and second booms pivotally connected together at or near to adjacent ends, the first boom being for pivotal mounting on the structure and the distal end of the second boom mounting an attachment carrier, and means for controlling movement of the booms comprising a first hydraulic ram and cylinder arrangement being for connection between the structure and the first boom, second and third hydraulic ram and cylinder arrangements connected between the two booms, a fourth hydraulic ram and cylinder arrangement connected near to the pivotal connection between the two booms and a fifth hydraulic ram and cylinder arrangement connected between the second boom and the carrier, the ram and cylinder arrangements being in communication with a hydraulic fluid supply.

Preferably, a sixth hydraulic ram and cylinder arrangement is provided between the first boom and the structure. The first ram and cylinder arrangement is desirably pivotally mounted rearwardly of the first boom and the sixth hydraulic ram and cylinder arrangement is preferably pivotally mounted forwardly of the first boom. The fourth, fifth and sixth ram and cylinder arrangements are preferably in a first fluid communication circuit with a first valve bank. The first and third ram and cylinder arrangements are preferably in a second fluid communication circuit with a second valve bank.

A swing plate is desirably pivotaly mounted on the first boom on or adjacent to the pivotal connection between the first and second booms, the swing plate carrying one end of the fourth ram and cylinder arrangement and one end of each of the second and third ram and cylinder arrangements. The pivotal mountings on the swing plate of the second and third ram and cylinder arrangements may be at the same position or at closely spaced separate positions.

Alternatively, the cylinders of the second and third ram and cylinder arrangements are secured back-toback, with the ram of the second ram and cylinder arrangement pivotally connected to the second boom and the ram of the third hydraulic ram and cylinder arrangement pivotally connected to the first boom. The fourth and fifth hydraulic ram and cylinder arrangements preferably are in one fluid communication circuit with a first valve bank. The third and first hydraulic ram and cylinder arrangements are desirably in another fluid communication circuit with a second valve bank.

Preferably also, the second boom is cranked downwardly and forwardlyat its outer end.

Embodiments of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which: Fig. 1 shows a schematic side elevational view of a load handling apparatus according to a first embodiment of the present invention, the apparatus being mounted on a vehicle (shown in broken line) and with pipe lines being shown between components; and Fig. 2 shows a schematic side elevational view of a load handling apparatus according to a second embodiment, the apparatus being mounted on a vehicle (only a wheel and wheel arch being shown) and with pipe lines being shown between components.

Referring to the drawings, in general to both embodiments, the load handling apparatus for mounting on a structure, for example a rough terrain truck as shown in broken line, comprises a first or rear boom 10 and a second or main boom 12. The booms 10, 12 are pivotally connected together at 14 (or near to adjacent ends). The first boom 10 is for pivotal mounting on the structure at 16 and the distal end of the second boom 12 mounts an attachment carrier 18. The second boom is cranked downwardly and forwardly at 11 at its forward end.

Means for controlling movement of the booms comprises a first hydraulic ram and cylinder arrangement 20 being for connection between the structure at 22 and the first boom 10 at 24. Second, or main lift, and third hydraulic ram and cylinder arrangements 26, 28 are connected between the two booms 10, 12 at points 30, 32 respectively. A fourth hydraulic ram and cylinder arrangement 34 is connected near to the pivotal connection 14 between the two booms 10, 12 at points 36, 38 respectively. A fifth hydraulic ram and cylinder arrangement 40 is connected between the second boom 12 and the carrier 18 at points 42, 44 respectively. The ram and cylinder arrangements 20, 26, 28, 34, 40 and 50 (to be described hereinafter) are in communication with a hydraulic fluid supply (not shown).

Fig. 1 shows a preferred embodiment of the load handling apparatus in which a sixth hydraulic ram and cylinder arrangement 50 is provided between the first boom 10 and the structure at 52. The first ram and cylinder arrangement 20 is pivotally mounted rearwardly of the first boom 10 and the sixth hydraulic ram and cylinder arrangement 50 is pivotally mounted forwardly of the first boom 10. The fourth, fifth and sixth ram and cylinder arrangements 34, 40 and 50 are in a first fluid communication circuit with a first valve bank 46.

The first and third ram and cylinder arrangements 20, 28 are in a second fluid communication circuit with a second valve bank 48. The two valve banks 46 and 48 are provided in communication with the fluid supply.

A triangular swing plate 54 is pivotally mounted on the first boom 10 adjacent to the pivotal connection 14 between. the first and second booms 10, 12. The swing plate 54 carries the cylinder end of the fourth ram and cylinder arrangement 34 and the cylinder end of the second ram and cylinder arrangement 26 and the piston end of the third ram and cylinder arrangement 28. The pivotal mountings on the swing plate 54 of the second and third ram and cylinder arrangements 26, 28 are shown at closely spaced separate positions but may be at the same position.

Referring to Fig. 2 of the drawings, in which like parts are denoted by like numerals, a second embodiment of the load handling apparatus is for mounting on a structure, for example the rough terrain truck of which a wheel 8 and a wheel arch 6 only being shown.

The means for controlling movement of the booms 10, 12 comprises a first hydraulic ram and cylinder arrangement 20 being for connection between the structure at 22 and the first boom 10 at 24. Second, or main lift, and third hydraulic ram and cylinder arrangements 26, 28 are connected together in alignment between the two booms 10, 12 at points 30, 32 respectively. The cylinders of the second and third ram and cylinder arrangements 26, 28 are secured, by welding, back-to-back, with the ram of the second ram and cylinder arrangement 26 pivotally connected to the second boom 12 and the ram of the third hydraulic ram and cylinder arrangement 28 pivotally connected to the first boom 10. The piston area of both rams of arrangements 20, 28 are identical. A fourth hydraulic ram and cylinder arrangement 34 is connected between the two booms 10, 12 at points 36, 38 respectively. A fifth hydraulic ram and cylinder arrangement 40 is connected between the second boom 12 and the carrier 18 at points 42, 44 respectively. The ram and cylinder arrangements 20, 26, 28, 34, and 40 are in communication with the hydraulic fluid supply.

The two valve banks 46 and 48 are provided in communication with the fluid supply.

In both embodiments, a control panel (not shown) with levers to actuate the valve banks 46, 48 is provided. Pipe line marked Y is connected to a safe load indicator (not shown). The second ram and cylinder arrangement is in a fluid communication circuit of its own the pipe lines from the two ports C and D being connected to a third valve (not shown).

In operation of the first embodiment, when a respective lever is actuated to raise the second boom, fluid is fed from port G on fourth arrangement 34 and into port K on fifth arrangement 40. Also, fluid is fed out of port L of fifth arrangement 40 and into port H of fourth arrangement 34 to keep the carrier 18 in a level position relative to the ground throughout the lift arc movement of the second boom 12. When a valve lever is moved on valve bank 46, fluid is fed out of the port Q and into port L of fifth arrangement 40 thus altering the attitude of the attachment carrier 18. Reverse movement in the attitude of the carrier is obtainable using a reverse sequence whereby fluid is fed from port P to port K.

If the second boom 12 is in the raised position and the fifth arrangement 40 is in a fully extended position, then when the boom 12 is being lowered, fluid from port H of the fourth arrangement 34 is bled or "dumped" across the circuit to a fluid tank shown diagrammatically at 56. Also, if the second boom 12 is in the lowered position and the fifth arrangement 40 is in a fully retracted position then when the boom 12 is raised fluid would be "dumped" from port G on fourth arrangement 34 across to the tank 56.

When valve lever is moved on valve bank 48, fluid is fed from port R to port N on the first arrangement 20 thus moving the boom 10 forwardly. To correct the consequential downward movement of the outer end of the boom 12, fluid is displaced from port M of arrangement 20 into port F of the third arrangement 28 which operates the swing plate 54. This action moves the plate 54 and has the effect of keeping the outer end of boom 12 moving in a level plane relative to the truck as the boom 10 moves forward.

When the boom 10 is moving forward by extension of first arrangement 20, the angle of the boom 12 alters as pivot point 14 rises in a forward pivotal arc. This change in angle alters the attitude of the carrier 18 ie. forward in direction X. To correct this movement, fluid from port A of the sixth arrangement 50 is fed to port L of the fifth arrangement 40. This keeps any forks on the carrier 18 level throughout the forward movement. Also, in a reverse action, fluid is fed from port B of the sixth arrangement to port K of fifth arrangement 40. The piston rod diameter and the cylinder bore diameter of arrangements 40, 34, and 50 are the same.

In operation of the second embodiment, when a respective lever is pushed fluid is fed from port A on bank 48 to port B on the arrangement 20. This displaces fluid from opposite port C and this is fed to the arrangement 28 through port D. This in turn displaces fluid from its opposite port E back through port F in the valve bank 48. The effect of this is that as the boom 10 moves forward the boom 12 maintains its level position, thereby enabling at any height the horizontal positioning and placing of a load on an attachment mounted on the carrier 18. Extension or contraction of the ram of arrangement 34 causes consequential contraction or extension of the ram of arrangement 40 thereby to keep the carrier 18 vertical and any attachment thereon horizontal.

The hydraulic circuits above described are all provided with safety valves and relief valves.

Variations and modifications can be made without departing from the scope of the invention described above.

Claims

CLAIMS:

1. A load handling apparatus for mounting on a structure comprising first and second booms pivotally connected together at or near to adjacent ends, the first boom being for pivotal mounting on the structure and the distal end of the second boom mounting an attachment carrier, and means for controlling movement of the booms comprising a first hydraulic ram and cylinder arrangement being for connection between the structure and the first boom, second and third hydraulic ram and cylinder arrangements connected between the two booms, a fourth hydraulic ram and cylinder arrangement connected near to the pivotal connection between the two booms and a fifth hydraulic ram and cylinder arrangement connected between the second boom and the carrier, the ram and cylinder arrangements being in communication with a hydraulic fluid supply.

2. Apparatus as claimed in Claim 1, wherein a sixth hydraulic ram and cylinder arrangement is provided between the first boom and the structure.

3. Apparatus as claimed in Claim 2, wherein the first ram and cylinder arrangement is pivotally mounted rearwardly of the first boom and the sixth hydraulic ram and cylinder arrangement is preferably pivotally mounted forwardly of the first boom.

4. Apparatus as claimed in Claim 1, 2 or 3, the fourth, fifth and sixth ram and cylinder arrangements are in a first fluid communication circuit with a first valve bank.

5. Apparatus as claimed in Claim 1, 2, 3 or 4, wherein the first and third ram and cylinder arrangements are in a second fluid communication circuit with a second valve bank.

6. Apparatus as claimed in any one of Claim 2 to 5, wherein a swing plate is mounted on the first boom adjacent to the pivotal connection between the first and second booms, the swing plate carrying one end of the fourth ram and cylinder arrangement and one end of each of the second and third ram and cylinder arrangements.

7. Apparatus as claimed in Claim 6, wherein the pivotal mountings on the swing plate of the second and third ram and cylinder arrangements are at the same position or are at closely spaced separate positions.

8. Apparatus as claimed in Claim 1, wherein the cylinders of the second and third ram and cylinder arrangements are secured back-to-back, with the ram of the second ram and cylinder arrangement pivotally connected to the second boom and the ram of the third hydraulic ram and cylinder arrangement pivotally connected to the first boom.

9. Apparatus as claimed in Claim 1 or 8, wherein the fourth and fifth hydraulic ram and cylinder arrangements are in one fluid communication circuit with a first valve bank.

10. Apparatus as claimed in Claim 1, 8 or 9, wherein the third and first hydraulic ram and cylinder arrangements are in another fluid communication circuit with a second valve bank.

11. Apparatus as claimed in any one of the preceding Claims, wherein the second boom is cranked downwardly and forwardly.

12. A load handling apparatus substantially as hereinbefore described with reference to Fig. 1 or Fig.

2 of the accompanying drawings.