Apparatus for digging trenches

Abstract

An apparatus for digging a trench including (a) a substantial vertical guide means (2); (b) mounting means (4) connected to the guide means (2) and movable substantially parallel to the guide means (2); (c) first drive means to move the mounting means (4) relative to the guide means (2); (d) a chain digger attachment (1) including an elongated frame (5) and a continuous digging chain (6) substantially surrounding the periphery of the frame (5), the attachment (1) being pivotally connected at or adjacent one of its ends to the mounting means (4); (e) second drive means (15) to rotate the continuous digging chain (6) about the frame (5); and (f) third drive means (24) to pivot the attachment (1) about the mounting means (4).

Description

FIELD OF THE INVENTION

[0001] The invention relates to an apparatus for digging trenches. In particular, the invention relates to a chain digging assembly for attachment to a carrier and a method of forming trenches using such a chain digging assembly.

BACKGROUND OF THE INVENTION

[0002] Trenches are required to be dug in a number of industries. In the building industry, for example, trenches are required to be dug for the purpose of laying foundations.

[0003] In another example, the close proximity of trees to buildings, fences, pathways and other structures have given rise to problems. The roots of such trees may cause damage by interfering with the foundations of the structures, lifting the pathways surrounding the structures or by causing soil-moisture movement problems.

[0004] In many instances, it becomes necessary to cut the roots of the tree causing the damage. Basically, a trench is dug in close proximity to the tree. The roots are cut in order to render them inactive and stop them from encroaching further.

[0005] In the past, typical trenching apparatus have been a backhoe or a tractor type vehicle which has a digging bucket attached to a boom. These machines make wide transverse trenches into the ground and are used to prepare trenches for house foundations and pathways. However, once the operating environment is confined, these machines are difficult to manoeuvre and unable to cut tree roots and the ground cleanly.

[0006] One alternate type of machine has been specifically designed to operate in a confined environment where narrow trenches are required and large root diameters need to be cut. This machine includes a circular or disc like digger attachment mounted at one end of a small tractor type vehicle. The disc has a number of teeth, each with a cutting edge, located about the periphery of the disc. As the disc is rotated the teeth rotate and by lowering the disc the teeth dig into the ground. The disc does not remove the spoil from the trench and separate removal of the spoil is necessary. The disc is of about 1.2 meters in diameter and can cut a trench down to about 0.6 meters in depth.

[0007] However, this purpose built machine is still not able to carry out all the desired functions in a confined environment. For example as this machine uses a disc, it is not able to cut around and under any services which may be present such as water pipes, power lines or gas pipes.

[0008] This machine is also not able to cut deep trenches as the disc diameter is limited. Consequently this machine was modified to also include an elongated digger which has an appearance similar to a chain saw. The elongated digger is pivotally attached to the side of the vehicle and is used to bring spoil out of the trench initially cut by the disc and when deeper trenches are required. In operation, the elongated digger is rotated until it engages the ground. In the almost vertical position the digger can form a trench of about 1 meter in depth. However, to avoid fouling services which may be present it is necessary to employ a complicated combination of vehicle front and back movement with the pivotal movement. This is time consuming and may be dangerous as the services may be accidentally fouled.

[0009] A further digger machine is disclosed in Australian Patent No. 620,271 (“Wallace”). This patent discloses a chain digger of the chain saw type pivotally attached to a boom which is in turn pivotally attached to a vehicle. In essence, the apparatus disclosed in Wallace uses a combination of two pivotal movements. In operation, the chain digger is positioned in a non-vertical trenching position for engaging the ground. The deeper the desired trench the more the relative rotational movement between the boom and the chain digger. If a vertical hole is required, the operator must simultaneously and continually adjust the orientation of the boom and the chain digger. The chain digger also includes a pusher foot which can push the vehicle forward as the trench progresses in steps.

[0010] Like the other prior devices the difficulty in manoeuvring the chain digger makes the precise movement of the chain digger difficult to control and may be dangerous in confined environments where live services are present.

[0011] Object of the Invention

[0012] The present invention therefore aims to provide an improved apparatus for cutting and digging trenches which has sufficient versatility to enable cleanly cut trenches to be prepared in confined environments.

SUMMARY OF THE INVENTION

[0013] According to the present invention there is provided an apparatus for digging a trench including:

[0014] (a) a substantial vertical guide means;

[0015] (b) mounting means connected to the guide means and movable substantially parallel to the guide means;

[0016] (c) first drive means to move the mounting means relative to the guide means;

[0017] (d) a chain digger attachment including an elongated frame and a continuous digging chain substantially surrounding the periphery of the frame, the attachment being pivotally connected at or adjacent one of its ends to the mounting means;

[0018] (e) second drive means to rotate the continuous digging chain about the frame; and

[0019] (f) third drive means to pivot the attachment about the mounting means.

[0020] In this way, a wide variety of trenching positions are possible by using the combination of pivotal movement of the chain digger attachment and vertical movement of the mounting means. This arrangement represents a substantial improvement over the prior art and makes it possible to cut trenches in different positions relative to, for example, the vehicle upon which the apparatus is mounted and further in places where movement is confined or live services are in the vicinity of the trench. Preferably, the third drive means can pivot the attachment through up to 180 degrees.

[0021] Typically, the guide means comprises a frame along which the mounting means may slide to allow movement into the various trenching positions.

[0022] In a preferred form of the invention, the guide means is telescopic. Typically, in this form of the invention, the guide means includes sections in the frame that slide into one another. If the guide means is not telescopic, the height of the guide means remains fixed and does allow for the fact that the apparatus may need to be used in surroundings where there are height restrictions. In the telescoped form, the overall height of the apparatus can be lowered by the various sections of the guide means sliding within each adjacent section. In this form of the invention, the overall height of the apparatus is still dependant on the length and angle of the chain digger attachment.

[0023] In another preferred form, the apparatus further includes fourth drive means to move the mounting means transversely of the guide means.

[0024] The transverse movement of the mounting means adds yet a further dimension to the ability of the apparatus to dig a trench. The transverse movement allows the apparatus to dig a trench according to the location of services and built structures without moving the location of the base machine. Typically, the transverse movement may be a combination of a pair of independent transverse movements. In this arrangement, a further drive means is interposed between the fourth drive means and the mounting means. The fourth drive means moves the further drive means, and the further drive means moves the mounting means. This permits a wider range of transverse movement of the mounting means, beyond the width of the base machine.

[0025] Preferably, the mounting means is a platform. The use of a platform is advantageous as it provides a convenient base on which to mount the second drive means which sits on the platform as it is moved up and down the guide means, which may be in the form of a frame. In this form of the invention, preferably, the platform includes brackets which engage around slots in the frame to support the platform at any designated height.

[0026] In a particularly preferred form, the chain digger attachment is capable of being pivoted into an indefinite number of trenching positions. In one preferred form of the invention, the chain digger attachment is capable of being pivoted into a position that is substantially vertical to the guide means. In this position, the attachment can function substantially as an auger.

[0027] The digger chain more preferably, includes a plurality of cutting scoops which may be evenly spaced around the periphery of the attachment. The leading edges of the scoops are sharpened for cutting into the earth and in this way make for the easy removal of earth or other material to be removed.

[0028] In yet a further preferred form of the invention, the first, second, third, fourth and/or fifth drive means are hydraulically driven.

[0029] The digging apparatus of the invention by combining at least vertical and rotational movement permits the apparatus to be operated in very confined environments without the need for synchronous movement of the vehicle to which the apparatus is connected. By a combination of movements, the invention allows trenches to be prepared in circumstances that were hitherto unable to be prepared using prior art apparatus. For example, trenches can now be prepared with ease where services are present in the ground across the pathway of a proposed trench. The chain digger attachment can be angled to prepare the trench up to the service and then adjusted to be substantially vertical with the ground and the spoil removed by the chain digger attachment being operated as an auger. In certain situations, once the trench has been prepared next to the service, the digger attachment may even be positioned to trench underneath the service.

DESCRIPTION OF THE DRAWINGS

[0030] The invention will now be further illustrated by reference to the accompanying drawings.

[0031] FIG. 1 is a side view of the apparatus for digging trenches which is the subject of the invention.

[0032] FIG. 2 is a partial side view of the chain digger attachment of FIG. 1 shown in various digging positions.

[0033] FIG. 3 is a partial end view of the chain digger attachment of FIG. 1 shown in various trenching positions.

[0034] FIG. 4 is a reverse side view of the frame and chain digger attachment of FIG. 2.

[0035] In the drawings, like numbers refer to the same features in each of the Figures.

[0036] FIG. 1 shows in broad schematic form the trenching apparatus which comprises a chain digger attachment 1 connected through mounting platform 4 to frame 2. Frame 2 is mounted upon vehicle 3. The specific details of each of the components is described below, however, in broad operation chain digger attachment 1 is capable of being pivoted about the mounting platform 4 into a number of trenching positions (as shown in FIG. 2). Typically, the chain digger attachment 1 is about 2.5 meters in length. Mounting platform 4 (and consequently chain digger attachment 1) can move up and down frame 2.

[0037] This versatility is further shown in FIG. 2. In particular, the chain digger attachment 1 may achieve a trenching position parallel with frame 2 (shown as A-A in FIG. 2) and vertical to the ground. In operation, the chain digger attachment 1 can then function essentially as an auger by trenching a hole that is perpendicular with the ground. The digging of the trench is achieved by the mounting platform 4 being moved down into the ground.

[0038] As further shown in FIG. 2, the chain digger attachment 1 can be pivoted into an infinite number of different positions. Accordingly a wide variety of trenching positions are possible by using the combination of pivotal movement of the chain digger attachment 1 and vertical movement of the mounting platform 4. It is therefore possible to cut trenches in different positions relative to vehicle 3 than is currently possible with known apparatus.

[0039] The specific details of the apparatus are further described with reference to FIGS. 2, 3 and 4.

[0040] Chain digger attachment 1 comprises a support frame 5 with guide wheels 7 over which is passed the digging chain 6. In operation, the digging chain 6 moves around the support frame 5 in an elliptical pathway. Guide wheels 7 are attached to each end of support frame 5 to guide the digging chain 6 around the two ends of the ellipse. The digging chain 6 has a plurality of cutting scoops 8 evenly spaced around its perimeter. The leading edge 9 of each of the cutting scoops 8 are sharpened for cutting the earth and/or tree roots and are designed to retain and transport the earth to the surface. The chain digger attachment 1 has an aperture at the top end (not shown) to receive axle 10 which when rotated drives digging chain 6.

[0041] Support right angle platform 4 is movably mounted to plate 21 by brackets 11 which engage around slots in plate 21. The support right angle platform 4 moves up and down the channels 13 with the brackets 11 engaging in and around slots 12 to hold the support right angle platform 4 in place at any designated height. As more clearly shown in FIG. 4, support right angle platform 4 has a horizontal surface 14 on which motor 15 is mounted. Motor 15 drives cog 16 which ultimately drives axle 10 and in turn the digger chain 6.

[0042] A two sided mounting plate 17 is pivotally connected by journals 18 to corresponding cross-bars 19 on each side of the support platform 4. An aperture (not separately shown) in each mounting plate 17 corresponds to the aperture in support frame 5 and receives axle 10 which is driven by cog 22. Cog 22 is connected by chain 23 to cog 16 (which as described above is driven by motor 15).

[0043] Mounting plate 17 holds the digger chain 6 in its various trenching positions as illustrated in FIG. 2 as W, X, Y and Z. Those positions may be infinitely varied by operation of piston 24 on mounting plate 17 via pin 25. Typically the positions may span up to 180 degrees. Piston 24 is hydraulically driven by movement of hydraulic fluid through the fluid inlet 26 and fluid outlet 27.

[0044] As shown in FIG. 3, digger chain 6 may be moved laterally with respect to vehicle 3, or with regard to the positioning required or access available. In FIG. 3, three positions K, L, M are shown, though it is to be understood that an infinite number of variations are possible.

[0045] In operation, the vehicle 3 is positioned and digger chain 6 is rotated about axle 10 to engage the ground. The digger chain 6 is already moving under the influence of motor 15. The scoops 9 cut into the earth and roots. The digger chain attachment 1 can be moved further into the earth by vertical movement of it down frame 2. This is actuated hydraulically in the same way as the pivotal motion of chain digger attachment 1 about axle 10.

[0046] By combining vertical and pivotal movement it is possible to dig trenches deeper and in more confined areas than is currently possible with known machines. Likewise, it is possible to dig precisely about services. The position of the trench can also be readily varied.

[0047] It is to be understood by those skilled in the technology that many variations or modifications in details of design or construction may be made without departing from the essence of the present invention. Such skilled addressees will appreciate that all such modifications and adaptations are included in the scope of the invention. Therefore, the invention should be understood to include all such variations and modifications within its scope.

Claims

1. An apparatus for digging a trench including:

(a) a substantial vertical guide means;

(b) mounting means connected to the guide means and movable substantially parallel to the guide means;

(c) first drive means to move the mounting means relative to the guide means;

(d) a chain digger attachment including an elongated frame and a continuous digging chain substantially surrounding the periphery of the frame, the attachment being pivotally connected at or adjacent one of its ends to the mounting means;

(e) second drive means to rotate the continuous digging chain about the frame; and

(f) third drive means to pivot the attachment about the mounting means.

2. The apparatus according to

claim 1, wherein the guide means is a frame along which the mounting means slides.

3. The apparatus according to either

claim 1 or

claim 2, wherein the guide means is telescoped.

4. The apparatus according to

claim 2, wherein the frame includes at least two sections which slide within each other to allow telescopic extension and retraction.

5. The apparatus of any one of

claims 1 to

4 wherein the third drive means is adapted to pivot the attachment about the mounting means through up to 180 degrees.

6. The apparatus according to any one of

claims 1 to

5, including fourth drive means to move the mounting means transversely of the guide means.

7. The apparatus of

claim 6 including fifth drive means interposed between the fourth drive means and the mounting means to move the mounting means transversely of the guide means.

8. The apparatus of any one of

claims 1 to

7, wherein the mounting means is a platform.

9. The apparatus of

claim 8, wherein:

(a) the platform further includes brackets; and

(b) the frame further includes slots, wherein in use the brackets engage in and around the slots to support the platform at a predetermined height.

10. The apparatus of any one of

claims 1 to

9, wherein the chain digger attachment is an auger.

11. The apparatus of any one of

claims 1 to

10, wherein the digger chain includes a plurality of cutting scoops.

12. The apparatus of

claim 11, wherein the digger chain includes a plurality of cutting scoops evenly spaced around the periphery of the attachment.

13. The apparatus of

claim 11 or

claim 12, wherein the leading edges of the scoops are sharpened.

14. The apparatus of any one of

claims 1 to

13 wherein the first, second, third, fourth and/or fifth drive means are hydraulically driven.

15. An apparatus for digging a trench substantially as hereinbefore described with reference to the accompanying drawings.