GB2397287A - Working arm for a machine - Google Patents

Abstract

A working arm 10 for a machine includes at least first 12 and second 13 relatively telescopic sections, one of the first 12 and second 13 sections including a mounting 60 by which the arm 10 is connectable to a body of the machine, and the first section 12 having a first internal chamber 18 into which pressurised fluid may be introduced, and the second section 13 including a piston 30 moveable in the first internal chamber 18 in one direction as a result of pressurised fluid being introduced into the internal chamber 18 at a first side of the piston 30 and being moveable in the first internal chamber 18 in a second opposite direction as a result of pressurised fluid being introduced into the first internal chamber 18 at a second opposite side of the piston 30, the internal chamber having a port 20 which is connectable to a fluid system of the machine and the first section 18 including between a chamber wall 48 and an external wall 49 of the first section 12, a passage 17 which extends from a first position 22 at which the passage 17 is connectable to the fluid system of the machine to a second position at or adjacent an end 23 of the first internal chamber 18 remote from the port, where the passage 17 is in fluid communication with the first internal chamber 18 at the second side of the piston 30.

Description

Title: Working Arm for a Machine

Description of Invention s

This invention relates to a working arm for a machine and more particularly but not exclusively to a working arm for a loading machine.

Working arms for loading machines typically include a plurality of sections which are telescoped together and are relatively moveable to extend and retract the working arm, by the operation of linear actuators.

In one arrangement a linear actuator is provided externally of the arm, the actuator having a cylinder part mounted on one of the arm sections and a piston part connected to the other of the sections. By introducing pressurised fluid into the cylinder part at one side of the piston, the arm is extended, and by introducing pressurized fluid into the cylinder part at a second opposite side of the piston, the arm is retracted, in each case fluid being ejected from the respective second and first side of the piston to a lower pressure line, or to tank, as pressurised fluid is introduced into the other side of the cylinder part.

It will be appreciated that with such an arrangement it is a requirement for pressurised fluid to be fed along the arm via a hose, from the machine body, to a distantmost end of the actuator so that pressurised fluid may be fed to, and fluid ejected from the respective sides of the piston during actuator operation.

The provision of the external actuator and necessary hoses can provide a substantial obstacle to the operator's visual field. Even when the actuator is mounted on an upper surface of the arm, this can present a visual obstacle when the arm is operated in a low position, for example when placing a load on the ground.

It has been proposed to mount the actuator internally of the working arm, but there are space restrictions, and in such a position, maintenance of the actuator is awkward. Also as the arm extends and retracts, hose movements have to be accommodated so that there is no risk of a hose being entangled.

According to a first aspect of the invention we provide a working arm for a machine, the arm including at least first and second relatively telescopic sections, one of the first and second sections including a mounting by which the arm is connectable to a body of the machine, and the first section having a first internal chamber into which pressurised fluid may be introduced, and the second section including a piston moveable in the first internal chamber in one direction as a result of pressurized fluid being introduced into the internal chamber at a first side of the piston and being moveable in the first internal chamber in a second opposite direction as a result of pressurised fluid being introduced into the first internal chamber at a second opposite side of the piston, the internal chamber having a port which is connectable to a fluid system of the machine and the first section including between a chamber wall and an external wall of the first section, a passage which extends from a first position at which the passage is connectable to the fluid system to a second position at or adjacent an end of the first internal chamber remote from the port, where the passage is in fluid communication with the first internal chamber at the second side of the piston.

Thus whereas with a conventional arrangement, in which first and second arm sections are telescoped, but a separate actuator is required, along with all the necessary fluid hoses, in a working arm in accordance with the invention, no separate actuator is required to telescope the arm sections, and it is not necessary for a fluid hose to extend along the arm to a distant end of a linear actuator. By omitting the separate actuator and hoses, where previously these have been provided externally of the telescoped sections, the operator's visibility may substantially be improved by the present invention. Where previously a separate actuator and hoses have been provided internally of the working arm, with the present invention particularly access for maintenance is considerably facilitated and potential problems of hose entanglement do not arise.

Where the arm includes more than two telescoped sections, for example three sections, the second section may include an internal second chamber into which pressurised fluid may be introduced, and the third section may include a piston moveable in the second internal chamber in one direction as a result of pressurised fluid being introduced into the second internal chamber at a first side of the piston and being moveable in the second internal chamber in a second opposite direction as a result of pressurised fluid being introduced into the second internal chamber at a second opposite side of the piston.

Desirably, the second internal chamber at the first side of the piston communicates with the first internal chamber of the first section at the first side of the piston through a passage which extends through the piston, so that pressurised fluid to move the piston in the one direction may be introduced into both of the first and second internal chambers at the respective first sides of the piston via the port of the first section. Moreover the second internal chamber at the second side of the piston may communicate with the first internal chamber of the first section at the second side of the piston, for example via a passage which is provided between a chamber wall of the second internal chamber and an external wall of the second section.

The or each piston may include a sealing arrangement to prevent pressurized fluid passing from one side of the piston to the other, and also a bearing structure to facilitate guiding the piston during its movement in the or the respective chamber.

At an end of the working arm remote from the mounting, a load handling implement may be provided which may be moveable relative to the arm, for example above a pivot axis, by one or more pressurised fluid actuators or otherwise.

In a preferred embodiment of the invention, at least one of the first and second working arm sections is made in a fibre-reinforced or other composite material, so that the passage between the chamber wall and the external wall of the section, may be provided integrally with the internal chamber. If necessary, the internal chamber of the or each section may be lined, particular over the longitudinal extent over which the piston moves.

The mounting by which the arm is connectable to a body of the machine may permit the arm to be pivoted up and down about a pivot axis of the mounting. To achieve this the machine may have one or more linearly acting lift actuators which extend between the arm and the body of the machine and which may be extended and retracted to pivot the arm.

Although a mounting for such lift actuator or actuators may be secured to the arm, preferably where at least a section of the arm is made of a composite material, such mounting is integrally provided as the arm section is made.

The invention has been particularly developed for use on a loading machine which includes a ground engaging structure afforded by ground engaging wheels carried by the body. The body may include a chassis and superstructure and the arm may be mounted on the superstructure or chassis and extend forwardly of a front of the machine generally transversely centrally of the machine, there being an operator's cab provided at one side of the working arm. In such a machine an engine to power the machine may be provided on an opposite side of the arm to the operator's cab, or behind the operator's cab, and steering of the machine may be effected by at least one of skid steering, and/or steerable wheels, and/or by articulating two articulated parts of the chassis.

According to a second aspect of the invention we provide a load handling machine having a working arm according to the first aspect of the invention.

Embodiments of the invention will now be described with reference to the accompanying drawings in which: FIGURE 1 is an illustrative side view of a working arm in accordance with the invention: FIGURE 2 is a cross section on the lines 2-2 of figure 1; FIGURE 3 is a cross section on the lines 3-3 of figure 1; FIGURE 4 is a cross section on the lines 4-4 of figure 1; and FIGURE 5 is an illustrative more detailed side view of a piston of the arm of figure 1.

Referring to the drawings, a working arm 10 for a machine includes a first section 12 and a second section 13, and a third section 14 only part of which can be seen, the sections being telescoped together as hereinafter described, so that the arm 10 length may be extended and retracted.

The first section 12 is in this example generally circular in cross section with a lobe 16, the section 12 affording an internal chamber 18 into and from which in use, pressurised fluid may pass, via a port 20. However the section 12 may be of another cross sectional configuration if desired as described below.

The lobe 16 provides a passage 17 for fluid which extends from a first position 22 to which a hose or the like of a fluid system of the machine may be connected, along the outside of the internal chamber 18 of the first section 12, towards an end 23 of the chamber 18 remote from the port 20. Preferably the passage 17 extends generally parallel to the axis of the internal chamber 18, but this is not essential.

In this example, and as is preferred, the first position 22 is at or adjacent an end 24 of the internal chamber 18 where the port 20 is provided, so that the passage 17 allows fluid to flow along a substantial part of the length of the section 12.

Within the internal chamber 18 of the first section 12, there is a piston of the second section 13. The second section 13 has a body 32 which includes a wider region indicated at 33, and a narrower region 34. The piston 30 is carried by the narrower region 34. The narrower region 34 extends through an opening 35 provided in the first section 12, so that as the piston 30 moves along the internal chamber 18 of the first section 12 to an extent restricted by the length of the narrower part 34 of the body 32 of the second section 13, the second section 13 of the arm, telescopes in and out of the first section 12.

In use, when it is desired to extend the arm 10, pressurised fluid, usually hydraulic fluid, is introduced into the internal chamber 18 of the first section 12 via the port 20 which is connected to the fluid system of the machine. The port is at a first side of the piston 30. This causes the piston 30 to move along the internal chamber 18 in the direction indicated by arrow A, thus to telescope the second section 13 outwardly. Fluid which is in the internal chamber 18 of the first section 12 at a second opposite side of the piston 30, may pass from the internal chamber 18 via the passage 17 which is connected via position 22 to tank, or another lower pressure region of the machine hydraulic system.

It can be seen that through the piston 30, there is an opening 40 which communicates with an internal chamber 41 of the second section 13. The internal chamber 41 extends throughout the second section 13, in both the wider 33 and narrower 34 regions.

In this example, within the internal chamber 41 of the second section 13, there is a piston 44 of the third arm section 14, which piston 44 may be substantially similar to the piston 30 of the second section 13.

Thus during extension of the arm 10, as pressurised fluid is introduced into port 20 and hence the internal chamber 18 of the first section 12, the pressurised fluid may also act upon a first side of the piston 44 of the third section 14, so that the third section 14 is telescoped outwardly of the second section 13. By metering the flow of fluid through the opening 40 of the second section piston 30, the second section 13 of the arm 10 may be arranged fully to extend from the first section 12 before the third section 14 telescopes outwardly, if this is desired, or both the second and third sections 13, 14 may be arranged simultaneously to move.

To permit fluid from the second side of the piston 44 of the third section, to be ejected from the second internal chamber 41, a further passage 45 is provided which communicates with the internal chamber 18 of the first section 12 at a second side of the piston 30. This further passage 45 is provided along the outside of the internal chamber 41 of the second section 13 of the arm 10 to a position closely adjacent the piston 30 of the second section 13, at the second side of the piston 30 within the internal chamber 18 of the first section 12. This construction can be seen in figure 3.

The first arm section 12 is in this example made of a fibre-reinforced or other composite material and has a circular cross section, provided by a chamber wall 48. The passage 17 is thus provided between the internal chamber À wall 48 and an external wall 49 of the first section 12, at least in the region of the passage 17.

An inside wall 50 of the internal chamber 18 is thus circular, and the piston 30 of the second section 13 has a generally circular periphery 52. The inside wall 50 of the internal chamber 18 may be lined if required, particularly for the longitudinal extent over which the piston 30 moves.

The second and/or third sections 13, 14 may too be made of fibre reinforced or other composite material or predominantly so. The passage 45 which extends along the outside of the internal chamber 41 of the second section 13, is again provided between a chamber wall 53 and an external wall 54 ofthe second section 13.

Where there are more than three telescopic sections of the working arm 10, the piston 44 of the third section 14 may have a through opening similar to opening 40 through the piston 30 of the second section 13, and the third section may provide a passage similar to passage 45 between an internal chamber wall of the third section 14 and an external wall of the third section, and so on, so that pressurised fluid for all of the working arm section internal chambers 18, 41 etc. at first sides of respective pistons 30, 44, can be provided by introducing fluid into the port 20 of the first section 12, and fluid may be returned from all respective second sides of pistons 30, 44 via the passages 45, 17 etc., to the position 22.

When it is desired to retract the arm 10, the direction of fluid flow is reversed by a valve (not shown) of the fluid system, so that pressurised fluid is fed from position 22 to the second sides of each of the pistons 30, 44 via the passages 17, 45, and return fluid flows to the port 20 and hence to tank or a lower pressure region of the fluid system, via the openings 40 through the piston 30 (or pistons 30, 44 where there is a fourth arm section).

10Whereas all of the arm sections 12, 13, 14 and their internal chambers 18, 41 etc. are in the example shown and described of circular cross section, by for example utilising pistons 30, 44 of other peripheral shapes, other cross sectional configurations may be used. Of course if desired, the internal chambers 18, 41 may be circular in cross section, but the external 15configurations of the sections 12, 13, 14 may be of entirely different cross sectional configurations as desired.

In figures 4 and 5, there is shown illustratively the piston 30 of the second section 13, which is of circular peripheral 52 configuration.

In the circular periphery 52, there is provided a first circumferential groove 56 which receives a piston ring P1, and a second axially spaced circumferential groove 57 receiving another piston ring P2, the piston rings P1, P2 thus providing a sealing arrangement to prevent pressurised fluid from one side of the piston 30, passing to the other side of the piston 30. Between the piston rings P1, P2 and grooves 56, 57, there is a bearing structure 58 provided by a plurality of caged balls 59, four in this example. Other bearing arrangements are possible.

In this example, the first arm section 10 provides a mounting 60 by which the arm 10 is connected to a body of a machine, in this example for pivotal movement about a pivot axis B of the mounting 60. To achieve such movement, there may be provided one or more linear actuators which extend between the arm 10 and a body of the machine. Particularly where the first section 12 of the arm 10 is made of fibre-reinforced or other composite material, a mounting 65 or mounting for such actuators may be provided integrally during section 12 manufacture.

At an end of the working arm remote from the mounting, a load handling implement may be provided which may be moveable relative to the arm, for example about a pivot axis, by one or more pressurised fluid actuators or otherwise.

The invention has been particularly developed for use on a loading machine which includes a ground engaging structure afforded by ground engaging wheels or tracks carried by the body. The body may include a chassis and superstructure and the arm may be mounted on the superstructure or chassis and extend forwardly of a front of the machine generally transversely centrally ! 15 of the machine, there being an operator's cab provided at one side of the working arm. In such a machine an engine to power the machine may be provided on an opposite side of the arm to the operator's cab, or behind the operator's cab, and steering of the machine may be effected by at least one of skid steering, and/or steerable wheels, and/or by articulating two articulated parts of the chassis.

The present invention avoids the need to provide any separate actuator to extend and retract the arm, or any hoses to feed fluid along the length of the arm to both ends of the actuator. Various modifications may be made to the embodiments described without departing from the scope of the invention.

The features disclosed in the foregoing description, or the following claims, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

Claims (11)

1. A working arm for a machine, the arm including at least first and second relatively telescopic sections, one of the first and second sections including a mounting by which the arm is connectable to a body of the machine, and the first section having a first internal chamber into which pressurised fluid may be introduced, and the second section including a piston moveable in the first internal chamber in one direction as a result of pressurised fluid being introduced into the internal chamber at a first side of the piston and being moveable in the first internal chamber in a second opposite direction as a result of pressurised fluid being introduced into the first internal chamber at a second opposite side of the piston, the internal chamber having a port which is connectable to a fluid system of a machine and the first section including between a chamber wall and an external wall of the first section, a passage which extends from a first position at which the passage is connectable to the fluid system to a second position at or adjacent an end of the first internal chamber remote from the port where the passage is in fluid communication with the first internal chamber at the second side of the piston.

2. An arm according to claim 1 wherein the arm includes a third section,, the second section including an internal second chamber into which pressurized fluid may be introduced, and the third section including a piston moveable in the second internal chamber in one direction as a result of pressurised fluid being introduced into the second internal chamber at a first side of the piston and being moveable in the second internal chamber in a second opposite direction as a result of pressurised fluid being introduced into the second internal chamber at a second opposite side of the piston.

3. An arm according to claim 1 or claim 2 wherein the second internal chamber at the first side of the piston communicates with the first internal chamber of the first section at the first side of the piston through a passage which extends through of the piston, so that pressurised fluid to move the piston in the one direction may be introduced into both of the first and second internal chambers at the respective first sides of the piston via the port of the first section.

4. An arm according to any one of claims 1 to 3 wherein the second internal chamber at the second side of the piston communicates with the first internal chamber of the first section at the second side of the piston.

5. An arm according to claim 4 wherein the second internal chamber at the second side of the piston communicates with the first internal chamber of the first section at the second side of the piston via a passage which is provided between a chamber wall of the second internal chamber and an external wall of the second section.

6. An arm according to any one of the preceding claims wherein the or each piston includes a sealing arrangement to prevent pressurised fluid passing from one side of the piston to the other, and also a bearing structure to facilitate guiding the piston during its movement in the or the respective chamber.

7. An arm according to any one of the preceding claims wherein at least one of the first and second working arm sections is made in a fibrereinforced or other composite material, and the passage between the chamber wall and the external wall of the section, is provided integrally with the internal chamber.

8. An arm according to any one of the preceding claims wherein the mounting by which the arm is connectable to a body of the machine permits the arm to be pivoted up and down about a pivot axis of the mounting by means of one or more linearly acting lift actuators which extend between the arm and the body of the machine which may be extended and retracted to pivot the arm, a mounting for such lift actuator or actuators being integrally provided with the arm as the arm section is made.

9. A working arm substantially as hereinbefore described with reference to and/or as shown in the accompanying drawings.

10. A load handling machine having a working arm according to any one of the preceding claims.

11. Any novel feature or novel combination of features described herein andlor as shown in the accompanying drawings.