WO2018153934A1

WO2018153934A1 - Device for an excavator

Info

Publication number: WO2018153934A1
Application number: PCT/EP2018/054306
Authority: WO
Inventors: James Russell
Original assignee: Individual
Current assignee: Individual
Priority date: 2017-02-21
Filing date: 2018-02-21
Publication date: 2018-08-30
Anticipated expiration: 2019-08-21
Also published as: GB201702793D0; GB201913499D0; GB2559811A; GB2574551A; GB2574551B

Abstract

A device for an excavator of the type comprising boom, a dipper arm pivotally mounted on a distal end of the boom and at least one ram acting between the dipper arm and a linkage member pivotally mounted on the dipper arm for operating a tool mountable on the dipper arm and coupled to the linkage member via at least one link rod, the device comprising a first guide adapted to be mounted adjacent a proximal end of the dipper arm, a second guide mounted to be displaceable away from the first guide, a cable anchored to a fixed point and extending between said first and second guides such that displacement of the second guide away from the first guide produces vertical movement at a free end of the cable.

Description

Device for an Excavator

Field of Invention This invention relates to a device for an excavator which can be fitted to a standard excavator, in particular to a back hoe, in order to use the excavator as a crane to lift heavy loads. This is achieved through harnessing an existing hydraulic piston which is used to control the motion of a tool at the end of the distal end of the dipper (such as a bucket) and translating the movement of the piston into a lift means closer to the centre of gravity of the excavator.

Background of Invention

The use of a variety of tool attachments for excavators such as buckets, rakes, thumbs, hammers etc. is known in the prior art. The uses of some of these types of tools (such as thumbs, grapples etc.) are specifically geared towards the action of lifting loads. Excavator manufacturers publish tables detailing the lift capacities of their excavators when using a hook at the end of the dipper arm. A disadvantage of using an excavator in lift activities is that the hook path is severely limited to an arc centred on the dipper hinge, and when the hook is lifted it moves away from the machine, increasing the radius and decreasing the safe load that may exceed the recommended limits, increasing the risk of instability and overturning of the excavator. It is therefore an object of the present invention to advance the technology for excavator arm attachments in order to make the swapping between excavator/lift activities more efficient, to increase the safe range of lift capacities for excavators and to introduce a new means of adapting an existing excavator to make it suitable for lift activities.

Summary of Invention

According to a first aspect of the invention, there is provided a device for an excavator of the type comprising boom, a dipper arm pivotally mounted on a distal end of the boom and at least one ram acting between the dipper arm and a linkage member pivotally mounted on the dipper arm for operating a tool mountable on the dipper arm and coupled to the linkage member via at least one link rod, the device comprising a first guide adapted to be mounted adjacent a proximal end of the dipper arm, a second guide mounted to be displaceable away from the first guide, a cable anchored to a fixed point and extending between said first and second guides such that displacement of the second guide away from the first guide produces vertical movement at a free end of the cable. Preferably the free end of the cable depends from the first guide.

In one embodiment the second guide is adapted to be mounted on or adjacent said linkage member adjacent a distal end of the dipper arm; such that, extension of the at least one ram acting between the dipper arm and a linkage member displaces the second guide away from the first guide, producing vertical movement at a free end of the cable.

In an alternative embodiment the second guide is associated with a further ram mounted on either the boom or the dipper arm such that extension of the further ram displaces the second guide away from the first guide, producing vertical movement at a free end of the cable.

In one embodiment the second guide may be, in use, mounted on a distal of the linkage member and said ram is adapted to act against the linkage member at a point between the pivotal connection of the linkage member with the dipper arm and the second guide. Alternatively the second guide is mounted on the at least one link rod, a distal end of said link rod being coupled to a distal end of the dipper arm by a further linkage such that movement of the second guide as the ram is extended and retracted follows a substantially liner path, substantially parallel to a longitudinal axis of the dipper arm. Said linkage member, at least one link rod and further linkage may between them define a parallelogram linkage arrangement.

Preferably the cable comprises, at a free end thereof, an attachment mechanism. The attachment mechanism may comprise a hook or an eye. The cable may be anchored, in use, to a point on the dipper arm, to one of the first and second guides, or to the boom. Preferably at least one of said first and second guides comprises a sheave or pulley.

The first guide may be, in use, mounted on the dipper arm or on a boom of the excavator.

In one embodiment the first and second guides and the cable are mounted on one side of the dipper arm. In an alternative embodiment at least two first guides may be provided, at least two second guides and two cables, one of each being provided on opposite sides of the dipper arm.

A tool or a coupling for a tool may be mounted to a distal end of the dipper arm. A ground engaging support may be mounted under the distal end the dipper arm. The device may further comprise a dipper arm adapted to be pivotally mounted on a boom of an excavator, at least one ram acting between the dipper arm and a linkage member pivotally mounted on the dipper arm for operating a tool mountable on the dipper arm and coupled to the linkage member via at least one link rod, wherein the first guide is mounted adjacent a proximal end of the dipper arm; the second guide is mounted on said linkage member adjacent a distal end of the dipper arm or on a distal end of a further ram; and the anchored cable extends between the first and second guides, such that, extension of the at least one ram or said further ram displaces the second guide away from the first guide, producing vertical movement at a free end of the cable.

In a further aspect of the present invention there is provided an excavator comprising a boom, a dipper arm pivotally mounted at a distal end of the boom, at least one ram acting between the dipper arm and a linkage member pivotally mounted on the dipper arm for operating a tool mountable on the dipper arm and coupled to the linkage member via at least one link rod, and a device in accordance with the first aspect of the invention, wherein the device comprising a first guide mounted adjacent a proximal end of the dipper arm; a second guide mounted on said linkage member adjacent a distal end of the dipper arm; and an anchored cable extending between the first and second guides, such that, extension of the at least one ram displaces the second guide away from the first guide, producing vertical movement at a free end of the cable.

The term "cable" used herein is intended to encompass any elongate flexible member of sufficient load bearing capacity, including but not limited to wound cables, ropes or chains.

Brief Description of Drawings Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 illustrates a side view of a device for an excavator in accordance with a first embodiment of the invention, use, fitted to a back hoe of a standard excavator and fitted with a tool (in this instance a bucket tool);

Figure 2 illustrates an enlarged portion of the device for an excavator of Figure 1 ;

Figure 2A illustrates a device for an excavator in accordance with a modified embodiment of the present invention;

Figure 3 illustrates the enlarged portion of the device for an excavator of Figure 2 wherein a cable is wound around a tab and a first guide, for storage;

Figure 4 illustrates a side view of the device of Figure 1 in use and holding a load

Figure 5 illustrates in schematic form, modified devices in accordance with the present invention wherein the first guide is located in a variety of different positions; Figure 6 illustrates in schematic form, a device in accordance with a further embodiment of the present invention, in use, wherein the cable is anchored to a second guide; Figure 7 illustrates in schematic form an alternative embodiment of the present invention; and

Figure 8 illustrates a further embodiment of the present invention wherein a separate ram is provided for displacing the second guide away from the first guide;

Figures 9A and 9B are side and plan views respectively of a further embodiment of the present invention wherein a pair of separate rams are provided for displacing respective second guides away from respective first guides using a pair of cables; and

Figures 10 and 1 1 illustrate further embodiments of the present invention wherein a separate ram or rams is provided for displacing the second guide away from the first guide, said separate ram or rams being mounted on the dipper arm. Detailed Description of Drawings

Referring now to Figure 1 - 4 of the accompanying drawings, there is illustrated a first embodiment of a device for an excavator in accordance with the present invention, generally indicated as 100, which is designed to allow a standard excavator to be transformed into a crane in order to lift a load. The term excavator is understood to include machinery such as a backhoe, trackhoe, bulldozer, crawler, diggers etc. or any other heavy construction equipment which comprises a boom 2, a dipper arm 18 and a tool 4, the tool 4 being activated through hydraulic means via the movement of a hydraulic dipper ram 10 on the dipper or hydraulic boom rams 3, 6 on the boom 2, or a combination of the movement of all of these rams 3,6,10.

The device 100 comprises a modified dipper arm which is designed to be connected to a boom 2 of an excavator while allowing a tool 4 to be fitted to the dipper arm 18 of the device and to be used as normal. The modified dipper arm 18 may be a modification applied to the existing dipper arm of the machine or may comprise a replacement for the existing dipper arm.

The boom 2 comprises a hydraulic boom ram 6 and a proximal end 8 of the device 100 is pivotally connected to the boom 2 such that movement of the hydraulic boom ram 6 generates a pivotal movement of the dipper arm 18 of the device 100. Similarly the device 100 includes a hydraulic dipper ram 10 and a distal end 12 of the device 100 is pivotally connectable to a tool 4 via a suitable coupling, such that movement of the hydraulic dipper ram 10 generates a pivotal movement of the tool 4 via an intervening linkage member 20 against which the dipper ram 10 acts and one or more link rods 25 acting between the linkage member 20 and the tool 4 or coupling thereof.

In Figures 1 and 4 the tool 4 is shown as a bucket however, it should be appreciated that any of the wide range of excavator tools which are suitable for connection to a dipper arm 18 could be used in conjunction with the device 100 and the invention is not limited to use of a bucket as the sole tool with which it can be used. In a similar fashion to a standard dipper arm, as different types of work (digging, hammering etc.) require different tools 4, a number of different tools 4 can be connected to the distal end 12 of the device 100, as required, typically via a suitable quick release coupling. Furthermore, the device 100 may be used as a crane without any tool 4 attached to the dipper arm 18.

The device 100 also comprises at least two cable guides 14, 16, preferably in the form of pulleys or sheaves. A first guide 14 is mounted on either a dipper arm 18 or on a boom 2 of an excavator to which the device 100 will be attached and a second guide 16 is attached to the linkage member 20. As shown in Figure 5, the first guide 14 can be located in a variety of different positions on either the dipper arm 18, the boom 2 or the hydraulic boom ram 6, the boom 2 and the hydraulic boom ram 6 being adjacent the proximal end 8 of the dipper arm 18. In all cases the first guide 2 is mounted adjacent the proximal end of the dipper arm 18, close to its pivotal connection to the boom 2, so that the lifting force is applied to the device by a load to be lifted relatively close to the centre of gravity of the machine, compared to situations where a tool at the distal end of the dipper arm 18 is used to lift a load, mitigating the risk of instability and overturning of the excavator.,

In standard excavator operations, the linkage member 20 is pivotally mounted to the dipper arm 18 at one end, with the second guide 16 mounted at or adjacent to an opposed end of the linkage member, the hydraulic dipper ram 10 being coupled to the linkage member intermediate the two ends thereof, inboard of the second guide 16, and at least one link rod 25 extending between the linkage member 20 and the tool 4 or intermediate coupling such that pivotal movement of the linkage member 20 by extension or retraction of the dipper ram 10 is transmitted into pivotal movement of the tool 4 via the link rod 25. The arrangement shown in Figure 2 of the second guide 16 at the distal end of the linkage member 20 serves to effectively increase the throw or displacement of the hydraulic dipper ram 10 acting on the second guide 16, such that extension of the dipper ram 16 displaces the second guide 16 away from the first guide 14, as will be described below in more detail .

The device 100 also comprises a cable 22, a first end 21 of the cable 22 being anchored onto the dipper arm 18 of the device 100 in the embodiments shown in Figures 1 to 4. The first end 21 may be anchored directly onto the dipper arm 18 in a fixed connection or alternatively the first end 21 of the cable 22 may be anchored to one of the guides 14, 16 via a terminal loop in the first end 21 of the cable 22 which is wrapped about the respective guide 14, 16. The means of anchoring the cable 22 to one of the guides 14, 16 is not fixed to use of a terminal loop, and the device 100 may comprise any other suitable means for forming this connection. The first end 21 of the cable 22 is preferably anchored at an intermediate position between the guides 14, 16. An opposed free end 23 of the cable 22 comprises an attachment mechanism 24, for example, but not limited to, a hook or a swivel hook, such that, a load which is captured by the attachment mechanism 24 may be lifted by extending the dipper ram 10, displacing the guides 14,16 away from one another.

It is envisaged that coaxially arranged sets of first and second guides 14,16 may be provided around which the cable may pass to provide increased mechanical advantage when lifting a load via the free end 23 of the cable 22. A potential problem with the arrangement shown in Figure 2 is that the second guide 16, when mounted at or adjacent a distal end of the linkage member 20, follows an arc as the dipper ram 10 is extended and retracted. This varies the resultant load applied to the second guide 16 by the dipper ram 10 as the dipper ram 10 is extended. In a modified embodiment shown in Figure 2A, the second guide 16 is mounted on a link rod 25, a distal end of the link rod being coupled to the distal end of the dipper arm 18 via a further linkage 26 so that the second guide 16 moves in a substantial linear motion in a direction substantially parallel to the longitudinal axis of the dipper arm as the dipper ram 10 is extended and retracted. The linkage member 20, link rod 25 and further linkage 26 may define an approximate parallelogram arrangement.

As illustrated in Figure 6, it is envisaged that the first end 21 of the cable 22 may be anchored directly to the second guide 16. Other guides may also be added to the device 100 on the dipper arm 18, the linkage member 20, the boom 2 or either of the hydraulic rams 6, 10, as required. The guides 14, 16 and the first end 21 of the cable 22 may be positioned on the same side of the device 100. Alternatively a second identical set of guides and an anchored cable 22 may be provided on an opposite side of the device 100, such that a load can be supported by two independently anchored cables on either side of the device 100, thereby producing a balanced load.

In a further embodiment, illustrated in Figure 7, the cable 22 may be anchored to the second guide 16, may pass around a third guide 30 mounted on the dipper 18 before passing around the second guide 16 and subsequently around the first guide 14. This arrangement provides increased rope travel for a given ram 10 extension.

The guides 14, 16 may take the form of pulleys, sheaves, protrusions or any other shapes comprising at least a partially curved surface about which the cable 22 can run without obstruction. The guides 14, 16 are mounted such that extension of the hydraulic dipper ram 10, or a further ram or other drive means, moves the guides 14, 16 apart, therefore the path followed by the cable 22 which passes around each of the guides 14, 16 is enlarged and the length of free cable 22 which hangs vertically from the first guide 14 is shortened. In shortening the free length of cable 22, the position of the attachment mechanism 24 (shown in Figure 1 and 4 as a hook) which is at the end of the free length of cable 22 is moved vertically upwards, therefore, when a load is attached to said attachment mechanism 24, the load is also lifted vertically upwards. In the preferred embodiment, the cable 22 at least partially passes around each of the guides 14, 16 once, however, an alternative embodiment could be envisaged wherein the cable 22 at least partially passes around multiple guides, two or more of which may be arranged coaxially, in order to increase the distance through which the attachment mechanism of the cable 22 is raised or lowered for a given displacement of the hydraulic dipper ram 10.

Guide means, such as spaced guide rollers between which the cable may be constrained to pass, said guide rollers preferably having a longitudinal axis parallel to the dipper arm, may be provided for guiding the cable on and off one or both of the guides 14,16, in particular where the cable depends from the first guide 14. One of both of the guides 14,16 may be provided with keepers, such as rollers having a rotational axis parallel to the axis of the respective guide, to retain the cable on the respective guide 14,16. The device 100 in the embodiments of Figures 1 to 4 takes advantage of the position of the guides 14, 16 and the cable 22 to harness the hydraulic dipper ram 10 which may leave the hydraulic boom ram 6 free for use in manipulating the position of the device 100 and indeed to assist in the lift capacity of the device 100. Use of the hydraulic dipper ram 10 to control the lift via a system of guides 14, 16 means that the attachment mechanism 24 may only move in a vertical position which can be useful for fine-tuning of the lift. In many instances, the majority of lift can be performed using the hydraulic boom ram 6 and the hydraulic dipper ram 10 can subsequently be used for the fine tuning of the lift when the lift is in its most sensitive height range (such as when the load is being placed in position or when a load is being removed from an enclosed space).

The ratio of hydraulic boom ram 3 movement to attachment mechanism 24 lift could be as large a 20:1 whereas the ratio of hydraulic dipper ram 10 movement to attachment mechanism lift 24 could be as low as 1 :1 . The use of all three rams 3, 6, 10 in the same lift activity means that loads can be lifted at a higher range of vertical heights and distances from an excavator cabin 26 than would be possible if the guides 14, 16 and cable 22 were attached directly to the boom 2. It is therefore apparent that the device 100 expands the operating envelope of excavators in the field of lift activities.

In instances where the boom 2 is used to lower the load; as the boom 2 is lowered it moves the device 100 (and therefore the attachment mechanism 24 and load) away from the cabin 26, thereby changing the position of the centre of gravity of the whole assembly and increasing the risk of instability or turning. In instances where the hydraulic boom rams 3,6 are not utilised, the boom 2 therefore retains a constant position with respect to the dipper arm 18 of the device 100. The full lift is controlled through use of the hydraulic dipper ram 10. This means that the load is lowered by moving the linking body 20 (and therefore the vertical position of the attachment mechanism 24) rather than lowering the boom 2 so that the cable 22, and therefore the position of the applied load, remains constant within a vertical plane which minimises the risk of instability and overturning. There is therefore an enhanced safety aspect involved in using the device 100 for lift activities.

In alternative embodiments one or more further rams 10A, independent of the dipper ram 10, or boom rams 3,6, may be provided for displacing the second guide 16 away from and towards the first guide 14. In the embodiment shown in Figures 8, 9A and 9B such further ram(s) may be mounted on the boom 2, with a single further ram 10A mounted beneath the boom 2, as shown in Figure 8, or a single further ram 10A mounted on one side of the boom 2, or a pair of further rams 10A on either side of the boom 2, as shown in Figures 9A and 9B.

Alternatively, as shown in Figures 10 and 1 1 , one or more further rams 10A may be mounted on the dipper arm 18, either on or both sides of the dipper arm 18, as shown in Figure 10, or beneath the dipper arm 18, as shown in Figure 1 1 .

The device 100 in accordance with an embodiment of the present invention may be initially attached in lieu of a standard dipper arm or may comprise a modification of the existing dipper arm. The device 100 may allow the use of the excavator as a traditional digger, ripper, hammer etc. depending on which tool 4 is attached. The guides 14, 16 and the cable 22 may be present on the device 100 while these traditional activities of the excavator are taking place, however, they are dormant during these activities. As shown in Figure 3, the cable 22 may be removed from around the second guide 16 when the second guide is associated with the dipper ram 10, and retained around a tab 28 when not being used for lift activities, in order to ensure that the cable 22 does not interfere with the conventional operation of the excavator.

When the excavator is being used to lift a load, provided that the attached tool 4 does not impinge on the space needed to carry out the lift, the tool 4 can be left in- situ while the lift activities are taking place. The tool 4 will move during these activities as use of the hydraulic dipper ram 10 is required during lift activities, however, the movement of the tool 4 is incidental to the lift activity. Alternatively, the tool 4 can be removed from the device 100 prior to commencement of the lift activities, if required.

In a preferred embodiment it is envisaged that at least one set of guides 14, 16 and cable 22 are integral features of the device 100. However, in a further embodiment, it is envisaged that the guides 14, 16 and cable 22, and optionally the linkage member 20 and/or link rod(s) 25 and/or further linkage 26 may be provided as a lift assembly to be retrofitted to a standard dipper arm, for example with a template outlining the required fitting positions on the existing standard dipper arm as an independent product.

In an alternative embodiment, it is envisaged that the device 100 further comprises a support (not shown) which is mounted under the distal end 12 of the dipper arm 18 such that the support may partially transmit any load acting on the attachment mechanism 24 to the ground or to an additional support with which it is in contact. The load acting on the attachment mechanism is therefore distributed between the support and the rest of the excavator, thereby extending the lift capability of the device 100. The invention is not linnited to the embodiments described herein but can be amended or modified without departing from the scope of the present invention as defined in the appended claims.

Claims

1 . A device for an excavator of the type comprising boom, a dipper arm pivotally mounted on a distal end of the boom and at least one ram acting between the dipper arm and a linkage member pivotally mounted on the dipper arm for operating a tool mountable on the dipper arm and coupled to the linkage member via at least one link rod, the device comprising a first guide adapted to be mounted adjacent a proximal end of the dipper arm, a second guide mounted to be displaceable away from the first guide, a cable anchored to a fixed point and extending between said first and second guides such that displacement of the second guide away from the first guide produces vertical movement at a free end of the cable.

2. A device as claimed in claim 1 , wherein the free end of the cable depends from the first guide.

3. A device as claimed in claim 1 or claim 2, wherein the second guide is adapted to be mounted on or adjacent said linkage member adjacent a distal end of the dipper arm; such that, extension of the at least one ram acting between the dipper arm and a linkage member displaces the second guide away from the first guide, producing vertical movement at a free end of the cable.

4. A device as claimed in claim 1 or claim 2, wherein the second guide is associated with a further ram mounted on either the boom or the dipper arm such that extension of the further ram displaces the second guide away from the first guide, producing vertical movement at a free end of the cable.

5. A device as claimed in claim 3 wherein the second guide is, in use, mounted on a distal of the linkage member and said ram acts against the linkage member at a point between the pivotal connection of the linkage member with the dipper arm and the second guide.

6. A device as claimed in claim 3, wherein the second guide is mounted on the at least one link rod, a distal end of said link rod being coupled to a distal end of the dipper arm by a further linkage such that movement of the second guide as the ram is extended and retracted follows a substantially liner path, substantially parallel to a longitudinal axis of the dipper arm.

7. A device as claimed in claim 6, wherein said linkage member, at least one link rod and further linkage between them define a parallelogram linkage arrangement.

8. A device as claimed in any preceding claim, wherein the cable comprises, at a free end thereof, an attachment mechanism.

9. A device as claimed in claim 8, wherein the attachment mechanism comprises a hook or an eye.

10. A device as claimed in any preceding claim, wherein the cable is anchored, in use, to a point on the dipper arm.

1 1 . A device as claimed in any of claims 1 to 9, wherein the cable is anchored to one of the first and second guides.

12. A device as claimed in any of claims 1 to 9, wherein the cable is anchored, in use, to the boom.

13. A device as claimed in any preceding claim, wherein at least one of said first and second guides comprises a sheave or pulley.

14. A device as claimed in any preceding claim, wherein the first guide is, in use, mounted on the dipper arm.

15. A device as claimed in any of claims 1 to 14, wherein the first guide is, in use, mounted on a boom of the excavator.

16. A device as claimed in any preceding claim, wherein the first and second guides and the cable are mounted on one side of the dipper arm.

17. A device as claimed in any preceding claim, comprising at least two first guides, at least two second guides and two cables, one of each being provided on opposite sides of the dipper arm.

18. A device as claimed in any preceding claim, wherein a tool or a coupling for a tool is mounted to a distal end of the dipper arm.

19. A device as claimed in any preceding claim, wherein a ground engaging support is mounted under the distal end the dipper arm.

20. A device as claimed in any preceding claim further comprising a dipper arm adapted to be pivotally mounted on a boom of an excavator, at least one ram acting between the dipper arm and a linkage member pivotally mounted on the dipper arm for operating a tool mountable on the dipper arm and coupled to the linkage member via at least one link rod, wherein the first guide is mounted adjacent a proximal end of the dipper arm; the second guide is mounted on said linkage member adjacent a distal end of the dipper arm or on a distal end of a further ram; and the anchored cable extends between the first and second guides, such that, extension of the at least one ram or said further ram displaces the second guide away from the first guide, producing vertical movement at a free end of the cable.

21 . An excavator comprising a boom, a dipper arm pivotally mounted at a distal end of the boom, at least one ram acting between the dipper arm and a linkage member pivotally mounted on the dipper arm for operating a tool mountable on the dipper arm and coupled to the linkage member via at least one link rod, and a device as claimed in any preceding claim, wherein the device comprising a first guide mounted adjacent a proximal end of the dipper arm; a second guide mounted on said linkage member adjacent a distal end of the dipper arm; and an anchored cable extending between the first and second guides, such that, extension of the at least one ram displaces the second guide away from the first guide, producing vertical movement at a free end of the cable.