NZ538164A - Post-driver - Google Patents

Abstract

A post-driver having a mast, a driving weight mounted for movement along the mast to drive a post adjacent the mast in to the ground, and an auger assembly mounted for movement between an operative position in which an auger is positioned adjacent the mast to drill in to the ground a hole for the post and a stowed position to permit placement of the post in to the hole, the post-driver further comprising a post guide system carried by the mast for guiding the post during driving in to the ground to maintain a required orientation of the post.

Description

NEW ZEALAND PATENTS ACT 1953 COMPLETE SPECIFICATION After Provisional 2004900732 filed in Australia on 13 February, 2004 Davies Collison Cave Reference: 12566940 538164 APPLICANT(S) Lyco Industries Pty Ltd of 15 Wiltshire Lane, Ballarat, Victoria 3350 Australia - An Australian company My/Our contact address is: My/Our address for service is: DAVIES COLLISON CAVE 1 Nicholson Street G.P.O. Box 4387QQ Melbourne 3000 Victoria, AUSTRALIA Telephone: 61 3 9254 2777 Facsimile 61 3 9254 2770 Email: chodkinson@davies.com.au DAVIES COLLISON CAVE d- James & Wells Level 9, James & Wells Tower 56 Cawley Street Private Bag 11907 DX CP 34005 Ellerslie Auckland NEW ZEALAND INVENTION TITLE: Post-driver We/I, Lyco Industries Pty Ltd hereby declare the invention for which we pray that a patent be granted to us, and the method by which it is to be performed to be particularly described in and by the following statement: 1 ! F2; V ; P \REC\NZ\Docs\ 12566940 41 doc - 10/2/05 P:\OPER-RSH\post-driver NZ.doc-09'02/05 - 1 POST-DRIVER The present invention relates to a post-driver for driving large posts, typically wood, steel, or concrete posts, into the ground such as in the construction of fencing.

According to one aspect of the present invention there is provided a post-driver having a mast, a driving weight mounted for movement along the mast to drive a post adjacent the mast into the ground, and an auger assembly mounted for movement between an operative position in which an auger is positioned adjacent the mast to drill into the ground a hole for 10 the post and a stowed position to permit placement of the post into the hole, said post-driver further comprising a post guide system carried by the mast for guiding the post during driving into the ground to maintain a required orientation of the post.

If the mast is itself mounted for movement in a fore-aft and/or a lateral direction such 15 movement can be used to adjust the inclination of the post prior to, and during, driving into the ground while the post is guided by the guide system carried by the mast.

According to another aspect of the invention there is provided a post-driver having a mast, a driving weight mounted for movement along the mast to drive a post adjacent the mast 20 into the ground, and an auger assembly mounted for movement between an operative position in which an auger is positioned adjacent the mast to drill into the ground a hole for the post and a stowed position to permit placement of the post into the hole, the post-driver further comprising a system for guiding the post during driving, said guide system having forward guide means carried by the mast for guiding a forward surface of the post in a 25 fore-aft direction and a lateral direction and rear guide means for guiding a rear surface of the post in a fore-aft and a lateral direction, the rear guide means being movable between an inoperative position to enable the post to be placed into a driving position adjacent the forward guide means and an operative position in which the rear guiding function is assumed. i 1 1 FEB - ' V E D ■ C ! P:\OPER\RSH\post-driver NZ.doc-09/02/05 The forward and/or rear guide means can comprise one or more sets of rollers appropriately configured to provide the required fore-aft and lateral guidance. In an alternative, the guide means can comprise guide surfaces for example formed by sheet or 5 plate material appropriately configured to provide the required fore-aft and lateral guidance. In one practical form, the guide surfaces may each be of sheet or plate material in angled relation extending in the length direction of the post.

The rear guide means may be mounted to the mast for swinging movement between its 10 operative and inoperative positions.

According to another aspect of the present invention there is provided a post-driver having a mast, a driving weight mounted for movement along the mast to drive a post adjacent the mast into the ground, and an auger assembly mounted for movement between an operative 15 position in which an auger is positioned adjacent the mast to drill into the ground a hole for the post and a stowed position to permit placement of the post into the hole, the auger assembly including a fluid cylinder actuable to displace the auger downwardly into the ground during drilling and to retract the auger following drilling, wherein actuation of the said cylinder is also operative to cause displacement of the auger assembly from one to the 20 other of its operative and stowed positions.

In one embodiment, the auger assembly is mounted to the mast for swinging movement about a vertical axis between its operative and stowed positions and actuation of the cylinder causes the assembly to be swung about that axis. In one practical form, the 25 cylinder itself extends vertically in the assembly and thereby parallel to the swing axis and actuation of the cylinder effects cooperation between a part of the assembly and a fixed helical track centred on the axis to thereby swing the assembly from one to the other of its operative and stowed positions.

P:'vOPER\RSH\post-driver NZ.doc-09/02/05 In one particularly preferred form, actuation of the cylinder causes the assembly to swing from its stowed to its operative position by cooperation with the helical track prior to commencement of drilling. Advantageously this movement occurs against the action of a spring bias and at the completion of drilling when the cylinder has caused withdrawal of 5 the auger from the hole the assembly is swung back to its stowed position under the effect of the spring bias.

According to yet another aspect of the invention, there is provided a post-driver having a mast, a driving weight mounted for movement along the mast to drive a post adjacent the 10 mast into the ground, and an auger assembly mounted for movement between an operative position in which an auger is positioned adjacent the mast to drill into the ground a hole for the post and a stowed position to permit placement of the post into the hole, wherein the position of the axis of the auger within the auger assembly is adjustable in a fore-aft direction as considered in relation to the operative position of the assembly to thereby vary 15 the fore-aft distance between the auger and mast in that position.

This adjustment in the fore-aft operative position of the auger permits ready adjustment to suit different cross-sectional sizes of post.

In one practical form, this adjustment can be achieved by providing within the auger assembly a slidable adjustable mounting for a component which carries the auger and a drive motor for the auger.

An embodiment of the invention will now be described by way of example only with 25 reference to the accompanying drawings in which: Figure 1 is a schematic side view of a post-driver in accordance with the invention and showing an auger assembly in a stowed position; Figure 2 is a plan view corresponding to Figure 1; Figure 3 is a side view showing the auger assembly deployed to an operative P:\OPER\RSH\posl-drivcr NZ.doc-09/02/05 position behind the mast of the post-driver to drill the ground in that position; Figure 4 is a plan view corresponding to Figure 3; Figure 5 is a side view showing a guidance system associated with the mast for guiding the post during driving into the ground, the auger assembly having been omitted 5 from this figure for clarity; Figure 6 is a rear view corresponding to Figure 5; Figure 7 is a schematic plan view showing forward and rear guide rollers of the guidance system in the position assumed during driving of the post; Figure 8 is a view similar to Figure 7, but showing the rear guide roller in an 10 inoperative position assumed prior to and after driving of the post; Figures 9 and 10 are plan views corresponding to Figures 7 and 8 but showing an alternative form of guidance system formed by angled guide surfaces; and Figures 11 to 13 are schematic plan views similar to Figures 7 and 8 showing an alternative form of mounting for the rear guide roller.

A post-driver in accordance with the preferred embodiment of the invention comprises a mast 2 mounted to support structure which is principally intended for mounting at the rear of a vehicle such as a tractor. In the form shown, the support structure comprises a lower frame 4 to which the lower end of the mast 2 is mounted by a pivot joint 6 such that the 20 mast 2 can be pivoted about the joint 6 in a lateral direction under the control of a fluid cylinder 8 (see Figure 6). The frame 4 and thereby the mast 2 is pivotal in a fore-aft direction under the control of a cylinder 10. Accordingly, by separately actuating the cylinders 8, 10 the mast 2 can be adjusted into a vertical or near-vertical orientation even when the tractor is standing on uneven ground. The support frame 4 itself is displaceable 25 laterally under the control of a separate fluid cylinder to permit relatively fine lateral adjustment of the position of the mast 2 to ensure that the post is driven in alignment with the required fence line. The described mounting arrangement which permits lateral and fore-aft adjustment of mast inclination and lateral adjustment of mast position, although preferred, is not essential and simpler forms of post-driver might have none of this P:\OPEIfcRSH\post-driver NZ.doc-09/02/05 adjustment or only some of this adjustment.

A driving weight 12 is mounted for sliding movement along the mast 2, the weight 12 being raised to the top of the mast by actuation of a fluid cylinder, with the weight then 5 falling under gravity to impact against a post positioned immediately to the rear of the mast 2.

The construction described thus far is substantially conventional and is present in some currently available post-drivers. The improvements relate to the deployment of an auger for forming the hole prior to driving of the post, an adjustable mounting for the position of the auger, and a guidance system for the post during post-driving. These aspects will now be described.

An auger assembly 14 mounted to the mast 2 includes an auger 16 extending downwardly 15 from a base 18 which also mounts an auger drive motor 20. The base 18 is mounted at the lower end of a vertical support 22 which is of telescopic construction. A vertical fluid-actuated cylinder 24 extends between an upper part of the telescopic support 22 and the base 18 so that actuation of the cylinder 24 will cause vertical displacement of the base 18 and thereby the auger 16 with such movement being guided by extension and contraction 20 of the telescopic support 22. The telescopic support 22 is itself pivotally connected to the mast 2 for swinging movement about a vertical axis "A" (see Figures 2 and 4) between an operative position of the auger assembly 14 in which the auger 16 is positioned behind the mast 2 for drilling of the hole (see Figures 3 and 4), and an inoperative stowed position to one side of the mast for the purposes of transportation and also to permit placement of a 25 post into the hole previously formed (see Figures 1 and 2). The actual pivotal connection between the telescopic support 22 and the mast 2 is not shown in the drawings. In this embodiment of the invention, movement of the auger assembly 14 between its operative and stowed positions is achieved by operation of the cylinder 24 which is principally used to displace the auger 16 into the ground during drilling and to withdraw the auger from the P:\OPER\RSH\post-driver NZ.doc-09/02/05 ground after drilling.

The stowed position of the auger assembly 14 is shown in Figures 1 and 2 in which the assembly is held in that position by a spring-loaded latch (not shown). In this position a 5 roller or other cam follower 26 mounted to the base 18 lies at the upper end of a helical cam track 28 mounted to the side of the mast 2 and centred about the pivot axis A. To move the auger assembly 14 to its operative position, the cylinder 24 is actuated to displace the base 18 downwardly. This initially causes release of the latch (although, alternatively, the latch could be manually released) and then, due to the interaction 10 between the roller 26 and cam track 28, the entire assembly 14 will be caused to swing inwardly about the axis A of the pivotal mounting to the position shown in Figures 3 and 4 in which the auger 16 is now positioned behind the mast 2 in the required position for drilling, the auger assembly 14 being held in this position by a further spring-loaded latch.

Drilling can then take place by actuation of the auger motor 20 and actuation of the cylinder 24 to advance the auger 16 into the ground during drilling. When drilling has been completed the cylinder 24 is actuated to withdraw the auger 16 from the hole. The cylinder 24 raises the base 18 to a height corresponding to that of which it will lie in its stowed position. The spring latch is then released manually and the auger assembly 14 is 20 then able to swing back into its stowed position by torsion springs associated with the pivotal mounting of the assembly; alternatively, the spring latch could be released in response to the action of the cylinder 24 raising the base 18. It will be understood that the torsion springs are loaded by the initial action of extending the cylinder 24 at the start of the cycle to force the assembly to swing inwardly against the spring bias as a result of the 25 cooperation with the helical cam track 28. In an alternative configuration, retraction of the cylinder 24 when raising the base 18 after drilling could induce, by cooperation with a suitable cam track, swinging displacement of the assembly to its stowed position thereby loading torsion springs which can swing the assembly to its operative position after release of the latch and other safety interlocks which may be required in that mode.

P:\QPER\RSH\post-driver NZ.doc-09/02/05 With the auger deployment system thus described, deployment/stowage of the auger takes place by the action of the cylinder present to effect driving advance and retraction of the auger, thereby obviating the necessity of installing a second cylinder just to effect 5 deployment/stowage.

Advantageously, the auger 16 and drive motor 20 are carried by a plate 18a (see Figure 4) mounted to a main plate 18b of the base 18 to which the cylinder 24 and telescopic support 22 are coupled, to permit limited adjustment of the position of the auger 16 and its drive 10 motor 20 in a fore-aft direction relative to the mast 2 when the auger assembly 14 is in its operative position. In the particular embodiment shown, the plate 18a is pivotally mounted to the main plate 18b so as to be able to swing in a fore-aft direction with provision for locking the plate 18b in a selected position for example by inter-engagement of a locking pin through aligned apertures in the two plates, although in other configurations the plate 15 may be mounted for a direct linear movement. The main affect of this adjustment is to enable the auger 16 to form the hole at a variable distance away from the mast 2 for usage with larger or smaller diameter posts and a correspondingly larger or smaller diameter auger and this is of particular benefit when used in conjunction with the post guidance system which will now be described.

The other aspect of the invention concerns the post guidance system to ensure that the post is maintained in an upright position during driving into the hole. The guidance system (see Figures 5 to 8) comprises one or more post guides 40 on the mast 2 to locate the forward side of the post 42 in a fore-aft direction and a lateral direction, and one or more guides 44 25 movable into a position behind the post 42 to guide the rear side of the post in a fore-aft and lateral direction. In the form shown in Figures 5 to 8, the guides 40, 44 are in the form of rollers of diablao (double-conical) shape which, when the post 42 is of a rounded cross-section, will provide the necessary fore-aft and lateral guidance. As shown, there are two such rollers 40 attached to the mast 2 at vertically spaced positions in the lower part of the P:\OPER\RSH\posl-drivcr NZ.doc-09/02/05 mast 2, with the upper roller 40 being below the lower limit of travel of the weight 12. The rollers 40 are so positioned that when the auger assembly 14 has been returned to its stowed position after the hole has been drilled, a post 42 placed by an operator against these rollers will be aligned with the hole. In the embodiment shown, the guide 44 for the 5 rear surface of the post 42 is provided by a roller of similar double-conical cross-section carried by an arm 46 pivotally attached to a bracket 48 fixed to the side of the mast.

The arm 46 is swung by operation of a fluid cylinder 50 between an open position as shown in Figure 8 in which the post 42 can be moved into position on the mast rollers 40, 10 and a closed position shown in Figure 7 which its roller 44 has moved into engagement with the rear side of the post. Although as shown, the arm 46 only carries a single roller 44, in alternative forms the arm 46 may carry two or more such rollers vertically spaced or there may be two or more such arms with associated rollers, the respective arms being vertically spaced so as to provide improved location for the rear of the post 42. When the 15 arm 46 closes onto the post 42 in the manner shown, the post 42 will be held between the opposed front and rear rollers 40, 44 in an upright manner as the post 42 is driven into the ground. If necessary, the fore-aft/lateral inclination of the mast 2 can be adjusted prior to driving the post into the ground to ensure that the post is held by the rollers 40, 44 in a precise vertical orientation at that stage.

In addition to maintaining the post in a predetermined orientation during driving into the ground, the guidance system can also be used to correct the inclination of the post during driving in case the orientation of the mast had not been precisely vertical at the commencement of post-driving. If, with the post 42 held in an initial orientation by the 25 guidance system, the post is driven part-way into the ground and its inclination is then checked and found to be off the vertical, either fore-aft and/or laterally, appropriate movement of the mast 2 by the cylinders which control the fore-aft and lateral inclinations of the mast will cause corresponding movement of the post while still held by the guidance system, so that the post can be pushed into a more precise vertical inclination and be held P:\OPER\RSH\post-drivcr NZ.doc *09/02/05 in that inclination until it has been fully driven into the ground. This facility assists significantly in ensuring the alignment of the respective posts along the fence line. It will be understood that this facility will not be provided in a post-driver which does not have provision for adjustment of the inclination of the mast, but even with that type of post-5 driver the maintenance of the post by the guidance system in a predetermined orientation during driving is still of significant benefit.

The cylinder 50 which swings the roller arm 46 to its closed position may, in its closed position, apply a forward loading to the associated roller(s) 44 so that the post 42 is 10 continually pressed against the forward rollers 40 in this mode. Accordingly, the position of the rear roller(s) 44 will self-adjust to the diameter of the particular post. However it is not essential for the post 42 to be pressed between the rollers 40, 44, and adequate guidance and alignment can still be achieved with some degree of play between the post 42 and the front and rear rollers 40, 44 and in circumstances where the post has an irregular 15 cross-section or an irregular surface, as opposed to a relatively smooth rounded surface in the case of the post 42 shown in the drawings, some degree of play may be necessary to ensure ease of passage of the post past the rollers as it is being driven into the ground. For this purpose, the roller arm 46 may instead be swung by operation of the cylinder 50 into at least one predetermined closure position (a STOP position) at which the arm 46 will then 20 be held so that its roller(s) 44 will not then push the post against the forward rollers 40. In that case it is preferred that the predetermined STOP position is adjustable to accommodate different types and cross-sections of post. The STOP position can be determined either by a mechanical stop associated with the mounting for the arm 46 or by appropriately controlling the fluid supply to the cylinder 50.

Although in the embodiment shown, the arm 46 is mounted for simple swinging movement between its open and closed positions, depending on the detailed design it may be mounted for movement along a more complex path between its open and closed positions possibly including a degree of rectilinear movement. One such arrangement will be described with P:\OPER\RSH\post-drivcr NZ.doc-09/02/05 reference to Figures 11 to 13 below.

When the post has been driven fully into the ground the arm 46 is returned to its open position to enable the post-driver to be moved forwardly away from the post to a position 5 to set the next fence post in the line.

The guidance function is not restricted to the use of double-conical rollers as described above. Sets of plain guide rollers, obliquely arranged would achieve a similar function. In fact it is not essential even to use rollers for this function. Figures 9 and 10 show a guide 10 arrangement formed by guides of angled form, a forward guide 60 being attached to the mast 2 and facing rearwardly and a rear guide 62 being attached to the swing arm 46 and facing forwardly. These guides can be inexpensively constructed from metal plate or sheet and can extend along a substantial part of the length of the post at the front and rear of the post to provide both fore-aft and lateral guidance. Although the two relatively inclined 15 guide surfaces of each guide are shown as being formed as a unitary structure they may alternatively be from separate lengths of sheet or plate and can be spaced. The previous discussion regarding the different modes of placement of the swing arm are equally applicable to this form of guide structure.

Figures 11 to 13 show an alternative mounting arrangement for the arm 46 carrying the rear roller 44 or other rear guide. In this arrangement the arm 46 is pivoted to a bracket 70 which is mounted for fore-aft movement to a further bracket 72 attached to the mast 2. The cylinder 50 is itself mounted to a bracket 74 for fore-aft movement against the bias of a compression spring 76. The mounting to the bracket 74 is via a threaded shaft 78 which 25 forms an extension of the cylinder body and is slidable through the bracket 74, the normal position of the cylinder 50 being determined by a nut 80 carried by the shaft 78 and engaged with the bracket 74. In an alternative, the threaded shaft 78 could be replaced by a rod apertured to receive pins in adjustable positions to engage the bracket and to form a stop for the spring.

P:\OPER\RSH\post-driver NZ.doc-09/02/05 In operation, to move the roller 44 from its open position (Figure 11) to its closed position (Figure 13), the cylinder 50 is retracted to cause the arm 46 firstly to swing inwardly to a position behind the post 42 (see Figure 12) and further retraction will then cause the 5 bracket 70 to displace forwardly thereby drawing the rear guide roller 44 against the rear of the post 42 (see Figure 13). This arrangement enables the closed position of the rear guide roller 44 to self-adjust to the cross-sectional size of the post 42. Further adjustment can also be obtained by displacing the cylinder by turning the nut 80 and an opposing nut 82 or by resetting the position of the pins in the alternative arrangement described above; this 10 type of adjustment is likely to be made to initially set-up the equipment to drive posts of a certain notional size. The spring mounting of the cylinder 50 enables the rear guide roller 44 to displace in a fore-aft direction during guidance to accommodate irregularities in the cross-sectional profile of the post 42. It is to be understood that this type of mounting system is applicable to other forms of guide such as the guide 62 shown in Figures 9 and 15 10.

Although the preferred embodiment of the invention features both the auger deployment system and post guidance system described, it is to be understood that they are able to be used separately. Accordingly, the auger deployment system can be used on a post-driver without the guidance system, and the guidance system can be used in a post-driver having another form of auger deployment mechanism.

Although as described the post is driven into a hole previously formed by operation of the auger, if the guidance system is used with a post having a pointed end, depending on soil 25 conditions the post may be able to be driven directly into the ground without pre-drilling as the guidance system will ensure that the post is held in a vertical orientation during driving and corrections in orientation can be made during this process by manipulating the mast in the manner described.

P:\OPER\RSH\posi-drivcr NZ.doc-09/02/05 Although in the form described, the post-driver is mounted to the rear of a tractor, in other forms it may be permanently built into/onto a prime mover to form a single-purpose unit.

The embodiments of the invention have been described by way of example only and modifications are possible within the scope of the invention.

P:\OPERNRSH\post-driver NZ.tloc-09/02'05

Claims (22)

CLAIMS:

1. A post-driver having a mast, a driving weight mounted for movement along the mast to drive a post adjacent the mast into the ground, and an auger assembly mounted for movement between an operative position in which an auger is positioned adjacent the mast to drill into the ground a hole for the post and a stowed position to permit placement of the post into the hole, said post-driver further comprising a post guide system carried by the mast for guiding the post during driving into the ground to maintain a required orientation of the post. 10

2. A post-driver having a mast, a driving weight mounted for movement along the mast to drive a post adjacent the mast into the ground, and an auger assembly mounted for movement between an operative position in which an auger is positioned adjacent the mast to drill into the ground a hole for the post and a stowed position to permit placement of the 15 post into the hole, the post-driver further comprising a system for guiding the post during driving, said guide system having forward guide means carried by the mast for guiding a forward surface of the post in a fore-aft direction and a lateral direction and rear guide means for guiding a rear surface of the post in a fore-aft and a lateral direction, the rear guide means being movable between an inoperative position to enable the post to be placed 20 into a driving position adjacent the forward guide means and an operative position in which the rear guiding function is assumed.

3. A post-driver according to claim 2, wherein the forward and/or rear guide means comprise one or more sets of rollers configured to provide the fore-aft and lateral guidance. 25

4. A post-driver according to claim 2, wherein the forward and/or rear guide means comprise guide surfaces configured to provide the fore-aft and lateral guidance.

5. A post-driver according to claim 4, wherein the guide surfaces are each of sheet or P:\OPER\RSH\post-drivcr NZ.doc-09/02/05 - 14- plate material in angled relation extending in the length direction of the post.

6. A post-driver according to any one of claims 2 to 5, wherein the rear guide means is mounted to the mast for swinging movement between its operative and inoperative 5 positions.

7. A post-driver according to any one of claims 2 to 6, wherein when the rear guide means is in the operative position it is operative to press the post against the forward guide means. 10

8. A post-driver according to claim 7, wherein the rear guide means is moved between its operative and inoperative positions by operation of a drive system including fluid cylinder, the drive system in the operative position of the rear guide means applying a forward loading to the rear guide means to thereby press the post against the forward guide 15 means. 20

9. A post-driver according to claim 8, wherein the drive system is such that the rear guide means is able to displace rearwardly against the effect of the forward loading to accommodate variations and/or irregularities in the cross-section of the post.

10. A post-driver according to any one of claims 1 to 6, wherein the rear guide means is moved between its operative and inoperative positions by operation of a drive system including a fluid cylinder, the operative position being a predetermined STOP position in which the rear guide means is set at a predetermined distance relative to the forward guide 25 means.

11. A post-driver according to claim 10, wherein the STOP position is adjustable.

12. A post-driver according to claim 10 or claim 11, wherein the drive system is such P:vOPER'RSH"vpos(-drivcr NZ.doc-09/02/05 20 25 - 15 - that the rear guide means is able to displace rearwardly against a resilient bias to accommodate variations and/or irregularities in the cross-section of the post.

13. A post-driver according to any one of claims 8 to 12, wherein the drive system includes a linkage associated with the cylinder and which causes the rear guide means to move from its inoperative to its operative position initially by a swinging movement in which the rear guide means is moved into a position behind the forward guide means and then by a linear movement in which the rear guide means is displaced forwardly towards the forward guide means. 10

14. A post-driver according to any one of claims 1 to 13, wherein the auger assembly includes a fluid cylinder actuable to displace the auger downwardly into the ground during drilling and to retract the auger following drilling, the arrangement being such that actuation of the said cylinder is also operative to cause displacement of the auger assembly 15 from one to the other of its operative and stowed positions.

15. A post-driver according to claim 14, wherein the auger assembly is mounted to the mast for swinging movement about a vertical axis between its operative and stowed positions and actuation of the cylinder causes the assembly to be swung about that axis.

16. A post-driver according to claim 15, wherein the cylinder extends vertically in the assembly and thereby parallel to the swing axis and actuation of the cylinder effects cooperation between a part of the assembly and a fixed helical track centred on the axis to thereby swing the assembly from one to the other of its operative and stowed positions.

17. A post-driver according to claim 16, wherein actuation of the cylinder causes the assembly to swing from its stowed to its operative position by cooperation with the helical track prior to commencement of drilling. P:\OPERRSH post-driver NZ.doc-07/03.05 - 16-

18. A post-driver according to claim 17, wherein the swinging movement of the assembly from its stowed position occurs against the action of a spring bias, and at the completion of drilling when the cylinder has caused withdrawal of the auger from the hole, the assembly is swung back to its stowed position under the effect of the spring bias. 5

19. A post-driver according to any one of claims 1 to 18, wherein the position of the axis of the auger within the auger assembly is adjustable in a fore-aft direction as considered in relation to the operative position of the assembly to thereby vary the fore-aft distance between the auger and mast in that position. 10

20. A post-driver according to claim 19 having a slidable adjustable mounting for a component which carries the auger and a drive motor for the auger whereby to provide for the adjustment of the position of the axis of the auger. 15

21. A post-driver according to any one of claims 1 to 20, wherein the mast is mounted for movement in a fore-aft and/or lateral direction such that movement of the mast can adjust, prior to and during driving, the inclination of a post held by the guide system.

22. A post-driver having a post guide system substantially as hereinbefore described 20 with reference to the accompanying drawings. DATED this 8th day of March 2005 Lyco Industries Pty Ltd 25 by their Patent Attorneys DAVIES COLLISON CAVE INTELLECTUAL PRnpFRTr^^P of ty.z - 9 MAS 2035 j I |