- 5 The invention has particular but not exclusive application to excavation apparatus adapted to excavate around the base of 1 a telegraph pole for periodic inspection purposes and for illustrative purposes only the invention will be described hereinafter in relation to such application. Of course the

10 excavation apparatus of the present invention can also be utilised to facilitate removal of other types of in-ground articles.

Mechanical excavating apparatus, such as endless chain mounted bucket excavators for excavating trenches and the like

15 and rotary augers for excavating holes are well known. However such apparatus has proven to be unsuitable for excavating around the base of poles and other buried articles with the result that considerable effort and expense is incurred in the inspection of telegraph and power poles for deterioration at

20 their base. For this purpose the present method necessitates workers shovelling dirt from around the base of such poles so that the normally concealed high stress areas may be inspected.

This invention aims to provide excavation apparatus 25 suitable for excavating around the base of poles and other in- ground articles which will be reliable and efficient in operation.

With the foregoing in view, this invention in one aspect resides broadly in excavation apparatus including:- 30 excavation means; a mounting assembly which may be assembled about a pole for guiding the excavation means about the pole, and ^' * drive means for driving the excavation means. ' The excavation means could be in the form a chain and

* 35 bucket digging means or any other suitable digging means adapted to be guided by said mounting means in an excavating

path about the pole. Preferably however the excavation means is a boring cylinder assembly which may be assembled about a pole for rotation thereabout and guided by the mounting assembly for substantially co-axial rotation and translation relative to the pole. The boring cylinder assembly could be formed of part-cylindrical segments which could be separately assembled about the pole but in a preferred embodiment the part-cylindrical segments are semi-cylindrical segments constrained by the mounting assembly for axial rotation. Suitably each part-cylindrical segment is captively supported by a respective mounting jaw operable to arrange the part-cylindrical segments in an cylindrical attitude or an open attitude, wherein the part-cylindrical segments may be separated from one another to enable them to be placed about or removed from a pole. «- The mounting jaws may be reciprocally moveable between the cylindrical attitude and the open attitude or they may be pivotally interconnected for pivotally moving the part-cylindrical boring segments between the cylindrical attitude and the open attitude. The mounting assembly could include an open jaw member adapted to be placed alongside a pole and provide support for a split boring cylinder assembly which may be assembled for rotation about the pole. In such arrangement the mounting assembly is constituted by the open jaw and the upper portion of the split boring cylinder assembly. Preferably however the mounting assembly includes opposed supporting jaws which may be assembled about a pole or the like so as to provide a continuous support about the pole for the excavation apparatus.

Suitably each mounting jaw supports a drive motor operable to rotate the boring cylinder assembly. Alternatively remote drive means such as a motor coupled to the excavation means by a drive belt could be utilised if desired. The drive motors on the jaw supports could be gear coupled to the excavation apparatus or chain or belt coupled thereto.

Any suitable means may be used to support the mounting

assembly for advancing it towards the ground and retracting it therefrom, such as a three point linkage of a tractor. Preferably however the mounting assembly is reciprocally supported on a mast and a hydraulic ram or a nut and shaft drive is utilised to cause translation of the mounting assembly along the mast. The mast may be suspended by a boom of a prime mover.

In another aspect, this invention resides broadly in excavation apparatus including:- a boring cylinder assembly; a mounting assembly rotatably supporting said boring cylinder assembly and having a mounting whereby said mounting assembly may be mounted to a prime mover for reciprocal movement relative to a post, and drive means on said mounting assembly for rotating said boring cylinder assembly, wherein said boring cylinder assembly has a plurality of cutting blades at its lower end, soil transfer flights for elevating soil from the advancing lower end of the boring cylinder assembly, and wherein said boring cylinder assembly comprises part-cylindrical body portions each captively supported by the mounting assembly and pivotable between a closed attitude, whereby the captively supported part-cylindrical body portions may be clamped together about a pole to form a boring cylinder which may be rotated about the pole, and an open attitude, at which the captively supported part-cylindrical body portions are separated from one another to permit the boring cylinder to be moved laterally relative to a pole for engagement about or disengagement from the pole. In order that this invention may be more readily understood and put into practical effect, reference will now be made to the accompanying drawings which illustrate a typical excavation apparatus of the invention and wherein:-

-FIG. 1 illustrates the excavation apparatus operatively positioned about a pole;

FIG. 2 illustrates the excavation apparatus in an

excavating attitude;

FIG. 3 is a plan view illustrating the excavation apparatus operatively positioned about a pole; FIG. 4 is a plan view corresponding to FIG. 3 but illustrating the boring cylinder assembly in an open attitude for removal from or engagement about a pole; FIG. 5 is a diagrammatic view of illustrating the support of one boring cylinder segment;

FIG. 6 illustrates the boring cylinder drive motor mounting arrangement, and

FIG. 7 illustrates the excavation apparatus positioned in its travelling configuration.

The excavation apparatus 10 is adapted for excavating about the base of a pole or other buried object and is thus adapted for cutting an annular trench about the pole and for conveying loose material removed during excavation to the ground surface. Furthermore the excavation apparatus 10 is particularly adapted for forming an annular trench about an existing pole and thus it includes a boring cylinder assembly 11 which includes two semi-cylindrical boring segments 12 and 13 supported by a jaw¬ like mounting assembly 14. The mounting assembly 14 includes opposed mounting jaws 15 and 16 pivotally connected together about a vertical pivot axis at 17. Each mounting jaw 15 and 16 is adapted to captively support a respective semi-cylindrical boring segment 12/13.

As illustrated in FIG. 4 the mounting jaws 15/16 may be pivoted so as to separate the semi-cylindrical boring segments 12/13 whereby their outer edges 19 and 20 may be separated sufficiently to enable the open boring cylinder assembly 11 to pass about a standing pole 9. Pivotal movement of the mounting jaws 15/16 is controlled by a hydraulic jaw operating ram 21 such that the jaws may be closed to clamp the semi-cylindrical boring segments 12/13 together to form the cylindrical boring assembly 11 or opened as desired. As can be seen in FIG. 1 the boring cylinder assembly 11 has a soil transfer flight assembly 23 extending around its

outer surface and a plurality of rotary-hoe like cutting blades 24 at its lower end. The mounting assembly 14 is vertically slidable along a mast 25 which is supported adjustably by the boom 26 of a prime mover whereby it may be raised and lowered, tilted or slewed.

In this embodiment the boom 26 connects pivotally to the mast 25 at 22 to enable the mast to pivot about a horizontal axis and a tilt control ram 27 extends between the boom 26 and the mast 25 whereby the inclination of the mast may be selectively varied. An elevating ram 30 is connected between the upper end of the mast and the mounting assembly 14 and is operable to force the boring cylinder assembly 11 into the ground. A further hydraulic ram 29 controls the elevation of the boom and may be retracted to raise the boom 26 or extended to force the foot 28 Of the mast 25 into engagement with the ground whereby, in use, the mast may be stabilised. The foot may be provided with a ground piercing pin to assist with stabilization if desired.

The mounting assembly 18 has a hydraulic drive motor 31 supported on each jaw 15/16 for driving a sprocket engaged with the exterior of respective drive chains 32 welded to the upper ends of the respective semi-cylindrical boring segments 12/13 so as to be continuous when these segments are closed to form the boring cylinder assembly. As illustrated in FIG. 6, each motor 31 is supported on a mounting arm 33 pivotally mounted at one end on a vertical axle 35 fixed to the respective jaw 15/16 and spring biassed at its other end for urging the drive sprocket 36 into driving contact with the chain 32. The spring biassing is provided by a compression spring 37 partly recessed into the end of a bolt 38 mounted on a jaw bracket 39 whereby the biassing may be selectively varied.

As illustrated in FIG. 5, each jaw 15/16 is provided with a pair of spaced, part annular bearing flanges 40 provided with opposed bearing grooves 41 which retain respective part annular AUSTLON or TEFLON bearings 42. Each boring segment 12/13 is provided with upper and lower collars 43 provided with

complementary bearing grooves 45 adapted to engage the bearings 42 whereby the boring cylinder segments 12/13 are positively located for rotation within the jaw about respective fixed axes which are coincident when the jaws 12/13 are closed. Furthermore the bearings axially locate the boring segments 12/13 relative to the mounting assembly 14 on relatively low friction bearings 42.

In use it will be seen that a power pole 9 or the like to be inspected can have the soil removed from around the base of the pole by engaging the open semi-cylindrical cylinder segments 12 and 13 about the pole and when so engaged actuating the jaw operating ram 21 to pivot the jaws 15/16 so as to move the semi-cylindrical segments 12/13 towards one another until the jaws are closed and the segments form a boring cylinder about the pole 9. The boring cylinder is then positioned concentrically about the pole 9 and the ram 29 is extended to force the base 28 of the mast 25 into engagement with the ground. *The hydraulic motors 31 may then be actuated to cause the semi-cylindrical segments"12/13 to rotate in unison as a cylinder about the pole with the cutting blades 24 penetrating the soil about the pole. This penetration is assisted by actuation of the hydraulic ram 30 so as to advance the boring cylinder assembly 11 into the ground about the pole. As the cutting tips 24 loosen material, it is excavated by the flights 23 and discharged outwardly onto the ground surface in known manner.

When the annular trench about the pole is excavated to a selected depth the boring cylinder assembly 11 may be elevated by retraction of the ram 30 -until it"is above the ground whereupon the jaw operating ram 21 may be actuated to open the jaws 15/16 and as a consequence the cylinder segments 12/13, so as to enable the excavation apparatus 10 to be moved away from the pole. The base of the pole may then be inspected with little or no manual excavation being required. It will of course be realised that the above has been given only by way of illustrative example of the invention and

that all such modifications and variations thereto as would be apparent to persons skilled in the art are deemed to fall within the broad scope and ambit of the invention as is defined in the appended claims.