WO2008106710A1

WO2008106710A1 - Trenching device

Info

Publication number: WO2008106710A1
Application number: PCT/AU2008/000185
Authority: WO
Inventors: Darren Leslie Murdoch
Original assignee: Individual
Current assignee: Individual
Priority date: 2007-03-07
Filing date: 2008-02-13
Publication date: 2008-09-12
Anticipated expiration: 2009-09-07
Also published as: AU2008222581A1; AU2008222581B2

Abstract

A trenching device including a coupling for attaching the trenching device to a vehicle for towing the trenching device, a cutting foot member having a cutting blade at a lower end thereof, wherein the cutting foot member is extendable downwardly relative to a frame of the trenching device to a fixed working condition below a level of surrounding ground surface so as to slice a layer of ground material as the vehicle is driven in a forward direction to form a trench.

Description

TRENCHING DEVICE

Field of the Invention

This invention relates to a trenching device, and more particularly, but not exclusively, to a trenching device for towing behind a vehicle.

Background of the Invention

It is known to form a trench, for example for laying irrigation, by using a self- propelled trenching vehicle fitted with a digging wheel. For example, large cross-country pipelines may be laid into trenches formed by operating large trenching machinery of the type having crawler treads for movement and a large digging wheel. An example model of this type of trenching machinery is known as a Cleveland 400W trencher. The Cleveland 400W is a very large (ie. 31 ,650kg) self-propelled trenching machine having crawler treads for providing drive relative to a ground surface, and a large digging wheel with toothed buckets for digging into the ground surface.

However, machines of this kind are large, slow, expensive and need to be transported to and from the site of a job. Furthermore, such machines have limited utility, and are thus impractical for many to purchase.

It is also known to provide a trencher attachment for coupling to a tractor by way of a 3 point linkage. Examples of tractor mounted trenchers are available through A. F. Trenchers Ltd and use a chain or a wheel to perform trenching. However, such trencher attachments are complex with many moving parts, multiple cutting elements subject to wear, and conveyors for transporting displaced material away from the trench.

Examples of the present invention seek to provide an improved trenching device. More specifically, examples of the present invention seek to provide a trenching device which is capable of performing trenching at an increased speed compared to current methods, and/or to provide a trenching device which is capable of leaving a neatly graded ground surface adjacent the trench, with displaced ground material at a convenient distance from the formed trench so as to improve access to the trench.

Summary of the Invention

In accordance with one aspect of the present invention, there is provided a trenching device including a coupling for attaching the trenching device to a vehicle for towing the trenching device, a cutting foot member having a cutting blade at a lower end thereof, wherein the cutting foot member is extendable downwardly relative to a frame of the trenching device to a fixed working condition below a level of surrounding ground surface so as to slice a layer of ground material as the vehicle is driven in a forward direction to form a trench.

Preferably, the trenching device includes a sweeping member extending outwardly from the cutting foot member for sweeping material of the layer away from the trench. More preferably, the sweeping member is fixed to the frame of the trenching device. Even more preferably, the material of said layer is displaced upwardly along the cutting foot member to the level of the surrounding ground surface where it is swept away from the trench by the sweeping member.

Preferably, the cutting foot member is arranged so as to be slidably adjustable to varying depths beneath the frame, such that the cutting foot member can be lowered for subsequent runs along the trench to slice further layers of ground material from the trench. More preferably, the sweeping member is able to be retracted for subsequent runs along the trench to sweep displaced ground material inside of previously swept ground material.

Preferably, the sweeping member is angled rearwardly from the cutting foot member so as to sweep the displaced material away from the trench as the vehicle is driven in the forward direction. Preferably, the sweeping member extends from either side of the cutting foot member so as to sweep the displaced material to opposite sides of the trench. Preferably, the sweeping member is in the form of a blade, and a lower edge of the blade is adapted to extend substantially along the surrounding ground surface so as to grade the surrounding ground surface as the vehicle is driven in the forward direction.

In a preferred example, a front face of the cutting foot member is rearwardly inclined such that the material of the layer is displaced upwardly along the front face, as the vehicle is driven in the forward direction, and to the level of the surrounding ground surface where it is swept away from the trench by the sweeping member.

Preferably, the front face of the cutting foot has a surface to promote displacement of the material of the layer upwardly along the front face as the vehicle is driven in the forward direction. More preferably, the front face has a surface with non-stick properties. Even more preferably, the front face has a Teflon (registered trade mark) surface.

Preferably, the trenching device has an auger for conveying the displaced material from the front face of the cutting foot to the sweeping member.

In accordance with another aspect of the present invention, there is provided a method of trenching with a trenching device driven by a vehicle coupled thereto, including the steps of: adjusting an extendable cutting foot member of the trenching device downwardly relative to a frame of the trenching device to a fixed working condition below a level of surrounding ground surface; and driving the vehicle to tow the trenching device in a forward direction such that a cutting blade at a lower end of the cutting foot member slices a layer of ground material as the vehicle is driven, thereby forming a trench.

Preferably, the method further includes the steps of displacing material of the layer upwardly along the cutting foot member to the level of the surrounding ground surface; and sweeping the material away from the trench substantially along the level of the surrounding ground surface by a sweeping blade extending outwardly and rearwardly from the cutting foot member.

Preferably, the method further includes the steps of further adjusting the cutting foot member to extend below a bottom surface of the trench; and driving the vehicle to tow the trenching device for a subsequent run along the trench to slice a further layer of ground material from the trench.

In accordance with another aspect of the present invention, there is provided a tooth blade element for attachment to a cutting foot member of a ground material cutting device, the tooth blade element including a substantially horizontal cutting edge facing frontward for cutting beneath a section of ground material, a ramped surface extending rearwardly of the horizontal cutting edge for feeding the section of ground material rearwardly, an upwardly facing side cutting blade for cutting a side of the section of ground material, and attachment means for attaching the tooth blade element to the cutting foot member.

Preferably, the attachment means includes an aperture in a sidewall of the tooth blade element for receiving a fastener to fasten the tooth blade element to the cutting foot member.

Brief Description of the Drawings

The invention is described, by way of non-limiting example only, with reference to the accompanying drawings in which:

Figure 1 is a perspective view of a trenching device in accordance with an example of the present invention;

Figure 2 is a top view of the trenching device;

Figure 3 is a side view of the trenching device; Figure 4 is a front view of the trenching device;

Figure 5 shows a close-up perspective view of a cutting blade of the trenching device;

Figure 6 is a side view of a trenching device, with a cutting foot member of the trenching device in a lowered working condition;

Figure 7 is a side view of the trenching device, with the cutting foot member raised;

Figure 8 is a rear perspective view of the trenching device being towed by a tractor vehicle;

Figure 9 is a view from beneath the tractor of the cutting foot member being used to form a trench;

Figure 10 is a side view of the trenching device being towed by the tractor in forming a trench;

Figure 11 is a rear perspective view of the trenching device being towed by the tractor in forming a trench;

Figure 12 is a rear view of the trenching device being towed by the tractor in forming a trench;

Figure 13 is a rear view of the trenching device raised on a three point linkage of the tractor;

Figure 14 is a close-up side view of the trenching device coupled to the tractor; Figure 15 is a close-up front view of a lower end of the cutting foot member;

Figure 16 is a detailed view of an auger of an example trenching device of the present invention;

Figure 17 is a top perspective view of a cutting foot member of an example trenching device of the present invention;

Figure 18 is a detailed front perspective view of a body of an example trenching device of the present invention; and

Figure 19 is a detailed side view of an example trenching device of the present invention shown in a raised condition.

Detailed Description

A trenching device 10 in accordance with an example of the invention, as shown in Figures 1 to 19, includes a coupling 12 for attaching the trenching device 10 to a vehicle 14 such that the trenching device 10 is able to be used as an accessory to a separate vehicle. Accordingly, the trenching device 10 increases the utility of the separate vehicle 14, which can also be used for purposes other than trenching. In the particular example shown, the coupling 12 is adapted for attachment to a three point linkage of a tractor 14, in the manner shown in Figures 8 to 14.

Advantageously, in contrast to self-propelled trenchers which use crawler treads for movement, the present trenching device 10 is able to be transported to and from jobs by simply raising the trenching device 10 on the three point linkage of the tractor 14, as shown in Figure 13.

The trenching device 10 has a cutting foot member 16 with a cutting blade 18 at a lower end thereof, as seen clearly in Figure 1. The cutting foot member 16 is extendable downwardly relative to a frame 20 of the trenching device 10, whereby the cutting blade 18 is able to be lowered into a trench 22 progressively over a number of passes along the trench 22, so as to slice a layer of ground material from the trench 22 with each pass. With reference to Figures 3, 6 and 7, for each pass, the cutting foot member is able to be extended to a suitable fixed working condition below a level 24 of surrounding ground surface 26 so as to slice a layer of ground material as the vehicle 14 is driven in a forward direction, thereby forming the trench 22. The trench 22 is deepened with each pass of the trenching device 10, by lowering the cutting foot member 16 relative to the frame 20, by approximately 100 to 150 millimetres per pass.

The trenching device 10 includes a sweeping member 28 which extends outwardly of the cutting foot member 16 for sweeping material 30 of the layer away from the trench 22 (see Figures 10 to 12). The sweeping member 28 is in the form of a V-shaped blade which extends rearwardly and outwardly of the cutting foot member 16, and which is fixed to the frame 20 such that it is able to remain substantially at the level 24 of the surrounding ground surface 26 so as to grade the surface despite varying depths of extension of the cutting foot member 16 relative to the frame 20 over the different passes. The material 30 of the layer is displaced upwardly along the cutting foot member 16 to the level 24 of the surrounding ground surface 26 where it is swept away from the trench 22 by the sweeping member 28.

The trenching device 10 is provided with an auger 32 for conveying the displaced material from the cutting foot member 16 to the sweeping member 28. The auger 32 has opposed left-hand and right-hand portions separated by a central auger splitter so as to divide the material 30 for sweeping by either side of the sweeping member 28. In contrast to existing trenchers which use augers, the present auger 32 rotates in the same direction as the wheels of the vehicle 14 so as to direct the material rearwardly to the sweeping member 28. As previous trenchers do not have a sweeping member, they generally require that the auger rotates in a direction opposite to rotation of the wheels of the vehicle so as to avoid directing the ground material behind the trencher. Furthermore, the auger 32 rotates at approximately 300 to 400 rpm, as opposed to augers used in existing chain type trenchers which rotate at approximately 100 rpm, so as to cope with the rate of displacement of material from the trench.

The auger 32 is positioned in front ^'of the sweeping member 28, and is generally within the horizontal plane of the sweeping member 28, extending in a direction substantially perpendicular to the direction of motion of the trenching device 10. The auger 32 is mounted such that the cutting foot member 16 is located approximately midway along the auger 32, and the auger 32 is supported at either end by supports depending from the frame 20. The central auger splitter is in the form of a central dividing disc 33, which bisects the auger 32 into the left-hand and right-hand portions, each of which is spiralled so as to convey the ground material 30 to either side of the central dividing disc 33 when the auger 32 is rotated in its rotational direction of operation (ie. the same direction of rotation as the wheels of the vehicle).

With reference to Figure 16, the left-hand portion spiral intersects the central dividing disc 33 a half-turn (ie. 180 degrees) from where the right-hand portion spiral intersects the central dividing disc 33. This results in a reduction in fluctuation of hydraulic pressure, as well as minimisation and equalisation of pulse loads on the hydraulic motor which rotates the auger 32 from one side of the auger 32. An opposite side of the auger 32 is supported by a bearing fitted to the respective support depending from the frame 20.

The central dividing disc 33 may be housed within a correspondingly curved part of the trenching device frame 20, to prevent rocks and the like from becoming jammed in the rotating auger.

With reference to Figures 6 and 7, the cutting foot member 16 is arranged so as to be slidably adjustable to varying depths beneath the frame 20 by way of a hydraulic cylinder supplied with hydraulic fluid by the vehicle 14, such that the cutting foot member 16 can be lowered for subsequent runs along the trench 22 to slice further layers of ground material from the trench 22. Similarly, the sweeping member 28 is supplied with hydraulic fluid from the vehicle 14 to control retraction of its ends 34 for subsequent runs along the trench 22 so as to sweep displaced ground material 30 inside of previously swept ground material, as shown in Figures 11 and 12.

As shown in the top view of Figure 2, the sweeping member 28 is angled rearwardly of the cutting foot member 16 so as to sweep the displaced material away from the trench 22 as the vehicle 14 is driven in the forward direction, and extends to either side of the cutting foot member 16 so as to sweep the displaced material 30 to opposite sides of the trench 22. Although the angle between arms of the V-shaped blade of the sweeping member 28 is indicated as being 70 degrees, it will be understood that this figure is provided as an example only, as are other dimensions shown in the drawings, and that variations to these values are possible within the scope of the invention.

A lower edge 36 of the sweeping member 28 is adapted to extend substantially along the surrounding ground surface 26 so as to grade the surrounding ground surface 26 as the vehicle 14 is driven in the forward direction. Accordingly, a neat level surface is provided at either side of the trench 22 to facilitate access to the trench 22 for laying of piping, cables, conduits and the like.

The cutting foot member 16 is rearwardly inclined such that the material 30 of the layer is displaced upwardly along a front face 38 of the cutting foot member 16, as the vehicle 14 is driven in the forward direction, and is displaced to the level 24 of the surrounding ground surface 26 where it is swept away from the trench 22 by the sweeping member 28. The front face 38 may be provided with a surface 40 to promote displacement of the material 30 upwardly along the front face 38. For example, the front face 38 may be provided with a non-stick surface using Teflon (registered trade mark) to promote flow of earth material upwardly along the cutting foot member 16.

With reference to Figures 5 and 15, the cutting blade 18 is formed of blade elements 42 which are able to be easily removed from the cutting foot member 16 for sharpening and/or replacement. Each of the side blade elements 42 has a frontward facing substantially horizontal cutting surface 44 for forming a bottom surface of the trench 22, as well as upper cutting surfaces 46 for forming side walls of the trench 22.

The trenching device 10 is supplied with hydraulic fluid from the vehicle 14 via hydraulic lines 48 to power the auger by a hydraulic motor, as well as to drive hydraulic actuators which operate sliding movement of the cutting foot member 16 as well as retraction/extension of the ends 34 of the sweeping member 28.

This trenching device 10 of this example does not take a whole depth of cut in one go, as do most other trenching machines (rotary or bucket chain etc), but instead relies on the ability to travel at an increased ground speed of between 8 kph and 10 kph but taking smaller and therefore more cuts of between 100mm and 150mm at a time.

Even though there has to be a number of cuts made to create a trench, the increased ground speed more than makes up for in time the number of cuts versus the finished trench in the traditional method. The higher speed allows the loose soil to be transferred up the gouge face at an increased velocity and to the top of the trench. The unit has a Teflon

(registered trade mark) coated blade.

The loose soil is augured to both the left and right of the machine, falling in front of the inclined blades of the sweeping member 28. These then sweep the broken soil to the side of the trench 22, leaving a neat windrow on both sides. They also leave a nicely graded clear path on each side of the trench 22. This is of course much better to work and walk on rather than having soil almost at the edge of the trench 22. The inclined blades of the sweeping member 28 are also extendable in order to put the initial load of soil further from the trench 22 and for subsequent passes the soil is placed closer to the trench 22 by retracting the blades. The vehicle pulling the trenching device then does not have to shift as much soil when the trench is at the required depth. The windrow that is left is wider and of a flatter nature than would be, if all the soil had to be kept being shifted as each pass was made. The face of the main extendable gouge of the cutting foot member 16 is covered with a non-stick Teflon (registered trade mark) coating that enhances the speed of removal of clay based materials that tend to stick to digging implements. From here, the material is directed into the hydraulically driven auger 32 and transmitted to the side of the device at a rapid rate. With regard to Figures 17 and 18, the non-stick coating is provided by way of a replaceable non-stick insert sheet 50 which is inserted into slots 52 formed on either side of the face of the gouge. Each of the slots 52 is formed behind a side cutting edge 54 which runs along the respective side of the gouge and has a generally "arrowhead" styled cross- section. Figure 18 shows a lower end of the non-stick insert sheet 50 adjacent a base of the cutting foot member 16, the base having a central scribe 55 which serves to cut or at least mark the ground material as it passes over to facilitate parting and movement of the ground material at the top of the gouge prior to entering the auger 32. This assists in the prevention of "packing" of ground material in front of the auger 32.

The tip of the cutting foot member 16 may vary in specific form according to the type of ground material to be cut from the trench. Where the material to be cut from the trench is clay, the tip may have a generally straight horizontal cutting edge; otherwise the tip may have spaced cutting teeth formed by opposed side blade elements 42 (as shown in Figure 18). The spaced cutting teeth may be formed by attaching side cutting edges 56 to typical "off-the-shelf excavator teeth, for example by welding. Alternatively, each of the spaced cutting teeth may be formed as a unitary piece, for example by casting.

The side cutting edges 56 of the cutting teeth improve the efficiency of the trencher significantly. The applicant proposes that if this design of tooth was utilised in conventional excavating machines (e.g. backhoes and excavators), considerable improvement in efficiency may be achieved. It may also be necessary for the machine operator to adapt their operating technique to suit the teeth with side cutting edges. Such components (bucket teeth) are typically very high usage items - it is common to find large containers of worn out teeth from excavators and the like. Non-stick Teflon (registered trade mark) sheeting may also be attached to the working surfaces 57 of the sweeping member 28 to facilitate movement of ground material along the working surfaces as the trenching device is driven forwards. Where the sweeping member 28 is extendable, non-stick surfacing may be fitted to both fixed and extending portions of the sweeping member 28. It is preferred that the non-stick surfacing be attached above a lower sweeping edge 58 which itself is also replaceable.

Again with reference to Figure 18, the body of the trenching device which serves as a sleeve in which the gouge is retracted is provided with bevel trim skirting 60 to trim shoulders of the trench edges at ground level. The bevel trim skirting 60 is provided on the subframe of the trench device body at ground level so that when the device is lowered for operation and the sweeping member 28 is spreading the spoil, the bevel trim skirting 60 forms a bevel to both top edges of the trench to stop loose edges collapsing back into the trench.

In the example shown in Figure 19, the gouge of the cutting foot member 16 is supported below ground level for additional strength. At location 62, the body of the trenching device extends below the level of the sweeping member 28 (and thus to below ground level when the trenching device is lowered) to give additional support to the gouge during the trenching operation. Advantageously, this also facilitates secure mounting of the bevel trim skirting 60 in an orientation suitable for its operation. Such configuration of the trenching device body results in the device digging a trench approximately 400mm deep before any hydraulic extension of the cutting foot member 16.

The device according to the example shown in the drawings can be used on any tractor that has 150hp to 300hp available or conversely on the back of a four wheel drive road grader that has the necessary hydraulics to operate it. The trenching device is quite unique not only in its design but also in that it does not need a highly powered machine to operate it, and therefore a direct saving in fuel may be achieved. The angles that are designed into the trenching device have been carefully selected and the cutting blade works in unison with the side sweeping member blades and the side auger.

The accompanying drawings give the detailed structure of an example trenching device showing all the necessary important and in some cases compound angles. Because of the manner in which these angles are associated to the pulling vehicle, it can be seen by the photographs that there is a large load being applied to the rear axle. This gives the cutting edge the action of pulling the vehicle harder onto the ground and cutting with a slicing motion or conversely the vehicle wanting to pull the cutting blade out of the ground and therefore peeling the soil away from the cutting edge.

While an example of the present invention has been described above, it should be understood that it has been presented by way of example only, and not by way of limitation. It will be apparent to a person skilled in the relevant art that various changes in form and detail can be made therein without departing from the spirit and scope of the invention. Thus, the present invention should not be limited by the above described example. For example, although the sweeping member 28 described above is extendable, in other examples, for example in smaller versions of the trenching device, the sweeping member may be fixed in length.

In one variation, the vehicle is provided with a Global Positioning System (GPS)/auto-steering arrangement and the trenching device is provided with a laser depth level, so as to facilitate achieving correct placement, depth and gradient/fall of the trench.

The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgment or admission or any form of suggestion that that prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates.

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. A trenching device including a coupling for attaching the trenching device to a vehicle for towing the trenching device, a cutting foot member having a cutting blade at a lower end thereof, wherein the cutting foot member is extendable downwardly relative to a frame of the trenching device to a fixed working condition below a level of surrounding ground surface so as to slice a layer of ground material as the vehicle is driven in a forward direction to form a trench.

2. A trenching device as claimed in claim 1, including a sweeping member extending outwardly from the cutting foot member for sweeping material of the layer away from the trench.

3. A trenching device as claimed in claim 2, wherein the sweeping member is fixed to the frame of the trenching device.

4. A trenching device as claimed in claim 2 or claim 3, wherein the material of said layer is displaced upwardly along the cutting foot member to the level of the surrounding ground surface where it is swept away from the trench by the sweeping member.

5. A trenching device as claimed in any one of claims 2 to 4, wherein the cutting foot member is arranged so as to be slidably adjustable to varying depths beneath the frame, such that the cutting foot member can be lowered for subsequent runs along the trench to slice further layers of ground material from the trench.

6. A trenching device as claimed in claim 5, wherein the sweeping member is able to be retracted for subsequent runs along the trench to sweep displaced ground material inside of previously swept ground material.

7. A trenching device as claimed in any one of claims 2 to 6, wherein the sweeping member is angled rearwardly from the cutting foot member so as to sweep the displaced material away from the trench as the vehicle is driven in the forward direction.

8. A trenching device as claimed in any one of claims 2 to 7, wherein the sweeping member extends from either side of the cutting foot member so as to sweep the displaced material to opposite sides of the trench.

9. A trenching device as claimed in any one of claims 2 to 8, wherein the sweeping member is in the form of a blade, and a lower edge of the blade is adapted to extend substantially along the surrounding ground surface so as to grade the surrounding ground surface as the vehicle is driven in the forward direction.

10. A trenching device as claimed in any one of claims 2 to 9, wherein a front face of the cutting foot member is rearwardly inclined such that the material of the layer is displaced upwardly along the front face, as the vehicle is driven in the forward direction, and to the level of the surrounding ground surface where it is swept away from the trench by the sweeping member.

11. A trenching device as claimed in claim 10, wherein the trenching device has an auger for conveying the displaced material from the front face of the cutting foot to the sweeping member.

12. A method of trenching with a trenching device driven by a vehicle coupled thereto, including the steps of: adjusting an extendable cutting foot member of the trenching device downwardly relative to a frame of the trenching device to a fixed working condition below a level of surrounding ground surface; and driving the vehicle to tow the trenching device in a forward direction such that a cutting blade at a lower end of the cutting foot member slices a layer of ground material as the vehicle is driven, thereby forming a trench.

13. A method of trenching as claimed in claim 12, further including the steps of: displacing material of the layer upwardly along the cutting foot member to the level of the surrounding ground surface; and sweeping the material away from the trench substantially along the level of the surrounding ground surface by a sweeping blade extending outwardly and rearwardly from the cutting foot member.

14. A method as claimed in claim 12 or 13, wherein the method further includes the steps of: further adjusting the cutting foot member to extend below a bottom surface of the trench; and driving the vehicle to tow the trenching device for a subsequent run along the trench to slice a further layer of ground material from the trench.

15. A tooth blade element for attachment to a cutting foot member of a ground material cutting device, the tooth blade element including a substantially horizontal cutting edge facing frontward for cutting beneath a section of ground material, a ramped surface extending rearwardly of the horizontal cutting edge for feeding the section of ground material rearwardly, an upwardly facing side cutting blade for cutting a side of the section of ground material, and attachment means for attaching the tooth blade element to the cutting foot member.

16. A tooth blade element as claimed in claim 15, wherein the attachment means includes an aperture in a sidewall of the tooth blade element for receiving a fastener to fasten the tooth blade element to the cutting foot member.