AU2003100592A4 - Post Driving Apparatus - Google Patents

Description

POST DRIVING APPARATUS TECHNICAL FIELD This invention relates to a post driving apparatus.

BACKGROUND ART Post driving apparatus such as that described in New Zealand Patent No. 174807 are commonly mounted on tractors via conventional three point linkage systems. A typical post driver comprises a tup (more commonly called a monkey) which is a heavy weight fixed to a vertical guide. The monkey is drawn up the guide and then set free so that it falls under gravity and impacts on a post to drive it into the ground. Outrigger legs can be used to stabilise the post driver when it is in use.

New Zealand Patent No. 174807 describes a cable and pulley system for raising a monkey, the system being actuated by a hydraulic ram with the mechanical arrangement being such that movement of the ram is translated via the pulley system to the monkey.

In arrangements of this type the post driver and vehicle need to be accurately positioned each time a post is to be driven into the ground. This is particularly the case if the posts are to form the basis for a structure such as a retaining wall or the like. In some cases the exact positioning is made difficult by conditions on site which may provide access and levelling problems. Where a post driver is mounted on a tractor it is generally positioned at the rear of the tractor and to one side. Such an arrangement makes the positioning of the tractor critical as there is little scope for sideways adjustments of position.

P:\WPDOCS\GRS\SPECI\78256233.doc 22f7/03 2 It is an object of the present invention to provide a post driving apparatus which goes at least some way towards overcoming the above problems or which provides the operator with the ability to position the post driver with the minimum of vehicle position changes, or which will provide the industry with a useful choice.

Further aspects and advantages of the present invention will become apparent from the ensuing description which is given by way of example only.

All references, including any patents or patent applications cited in this specification are hereby incorporated by reference. No admission is made that any reference constitutes prior art. The discussion of the references states what their authors assert, and the applicants reserve the right to challenge the accuracy and pertinency of the cited documents. It will be clearly understood that, although a number of prior art publications are referred to herein, this reference does not constitute an admission that any of these documents form part of the common general knowledge in the art, in New Zealand or in any other country.

It is acknowledged that the term 'comprise' may, under varying jurisdictions, be attributed with either an exclusive or an inclusive meaning. For the purpose of this specification, and unless otherwise noted, the term 'comprise' shall have an inclusive meaning i.e. that it will be taken to mean an inclusion of not only the listed components it directly references, but also other non-specified components or elements. This rationale will also be used when the term 'comprised' or 'comprising' is used in relation to one or more steps in a method or process.

P:\WPDOCS\GRS\SPECI\78256233.doc 22f7/03 DISCLOSURE OF INVENTION Accordingly, in a first aspect, the invention may broadly be said to consist in a post driver comprising: a base frame, attachment means adapted for attachment to a towing vehicle, a guide mounting a weight, and means for raising and releasing the weight on the guide wherein the guide is mounted to the base frame in a manner which enables the position of the guide to be adjusted in relation to the base frame.

Preferably, the base frame is substantially planar and the position of the guide is adjustable in the plane of the base frame.

Preferably, the position of the guide weight are adjustable in an arc or semicircle.

Preferably, the base frame is provided with an outer semi-circular or arcuate rail.

Preferably, the rail is in the form of a channel which provides support for a gearing or chain rack.

Preferably, a motor can drive a gear pinion or sprocket to provide for positional adjustments of the guide about the base frame.

Preferably, a pivotable arm supports and allows for movement of the guide with respect to the base frame.

P:\WPDOCS\GRS\SPECl\78256233-doc 2217103 Preferably, the arm is extendable or has telescopic capabilities.

Preferably, levelling means are provided for levelling the base frame, and/or guide Preferably, the levelling means provides for adjustment in two planes, fore and aft, and with respect to each side of the towing vehicle.

Preferably, outrigger legs are provided for stabilising the guide with respect to a particular operating site.

Preferably, the guide is telescopic which includes an outer housing and an inner housing and wherein the outer housing moves relatives to a static inner housing.

In a further aspect, the invention may broadly be said to consist in a method of using a post driver according to the first aspect comprising the steps of: locating the post driver within range of a post requiring driving, and (ii) adjusting the position of the guide on the base frame so that the weight can engage the post.

Preferably, the method further comprises the steps of: (iii) raising the weight along the guide, and (iv) releasing the weight to engage said post to provide post penetration into a surface.

P:\WPDOCS\GRS\SPECI\78256233.doc 2217/03 BRIEF DESCRIPTION OF DRAWINGS Further aspects of the present invention will become apparent from the ensuing description which is given by way of example only and with reference to the accompanying drawings in which: Figure 1: Figures 2 and 2a: Figure 3: is a perspective view of a post driver in accordance with a preferred embodiment of the present invention, and are diagrammatic side elevational views of levelling adjustment means utilised with the post driver of Figure 1, and is a diagrammatic side elevational view of an extending arm of the post driver of Figure 1 showing how the arm can be translated with respect to a rail of the base frame.

BEST MODES FOR CARRYING OUT THE INVENTION With respect to the drawings, a post driver is illustrated comprising attachment means generally indicated by arrow 1 which enable a post driver base frame generally indicated by arrow 2 to be adjustably fixed to a vehicle such as a tractor in a conventional manner. Brackets 3 fixed to the base frame 2 attach to fixtures on the towing vehicle and a piston 4 is connected between the towing vehicle and the base frame via an upright. Such an arrangement allows the piston 4 to be operated to effect primary adjustment of the plane of the base frame 2.

The base frame 2 comprises beam 6 and a substantially semi-circular or arcuate beam or rail 7 which is braced back to the beam 6 by strengthening PAkWPDOCS\GRS\SPECI\78256233.doc 2217/03 members 8. The beam or rail 7 may also be in the form of a box section or flat rail or channel. It will be seen that base frame 2 is substantially planar.

It can also be seen that the beam or rail 7 extends substantially through an angle of 180'. Although, alternatively, the beam 7 may also extend through an angle greater than 1800 The post driver apparatus a guide generally indicated by arrow 8, a weight or "tup" or "monkey" 9 which is keyed to and reciprocal with respect to the guide 8, and a drive mechanism generally indicated by arrow 10. The drive mechanism illustrated is similar to that described in New Zealand Patent No. 174807 in that the monkey 9 is keyed to the guide 8 and is reciprocal thereon. The monkey 9 is supported by a cable 11 which passes over a top set of pulleys 12,13 and then is connected to the apparatus via the drive means 10 and lower and intermediate pulleys 13, 14. A hydraulic ram 15 is connected directly to the intermediate pulley 14 and a control system is provided for actuating and deactivating the ram 15. Such a mechanical arrangement illustrated means that a small movement of the piston of the ram 15 results in a corresponding larger movement upwards of the monkey 9, the control system being such that once the monkey is in a raised position it can be deactivated to allow the monkey 9 to fall under gravity onto a post (not shown) below it.

Outrigger legs 16 can be used to stabilise the apparatus and in particular the guide, during post driving operations.

The guide 8 is supported with respect to the base frame by an extending arm 17 having a lower pivot joint 18 to the base frame 2. Arm 17 is supported by a brace 19 which extends back to a pivot point 20 on the upright 5. The arrangement described allows the arm 17, the guide 8 and P:\WPDOCS\GRS\SPECI\78256233.doc 22f7/03 the monkey 9 to be swivelled with respect to the base frame 2 in an arc or semi-circle.

Figures 2 and 2a of the drawings illustrate means for adjustment of the guide 8 and monkey 9 in two planes. As shown by figure 2, arm 17 can have a telescopic connection via member 22 with the guide 8. A doubleacting piston 23 can be operated to adjust the angle between the guide 8 and arm 17. Because piston 23 is connected between the guide 8 and beam 7 it is operable to provide for relative adjustment of the guide with respect to the beam.

Although it would be possible to manually adjust the position of the guide 8 and monkey 9 with respect to a rail or beam 7 it is preferred to make such adjustments automatically. One means of achieving this is illustrated by figure 3. Beam 7 can be fabricated from channel-section. A continuous chain 25 is positioned within the trough of the channel and a driving motor 26 and sprocket 27 connect with the chain. Motor 26 is fixed with respect to the arm 17 and the motor 26 is controlled to drive the arm 17 with respect to beam 7 in a semi-circle providing for changes of position of the guide 8 and monkey 9 with respect to the vehicle to which the post driver is attached.

It should be appreciated that the guide 8 may be telescopic so that its length can be reduced or increased to suit a particular post driving operation and for compactness during transportation. It may have an outer section to house the hydraulic operated cable and pulley system, and to which the monkey or tup operates on. Preferably, the outer housing or section of the telescoping guide 8 moves relative to an inner housing or section of the guide.

PAWPD0CS\GRSkSPECR78256233.doc 22/7/03 In use, it may be appreciated that the post driver is moved to by a vehicle such as, for example, a tractor or bulldozer, within range of a post requiring impact driving force (to penetrate the ground or a surface). The guide is then positioned and its position adjusted on the base frame 2 so that the lowermost position of the monkey is able to contact the post. The monkey is then raised above the post along the guide to a required height, before the monkey is then released from an uppermost position so that it falls to strike and engage the post.

Preferably the monkey is weight and/or height of fall is such that a penetrative force is provided to the post to penetrate the ground soil or surface.

The method of use as described herein may be repeated any number of times until a desired post penetration depth is achieved. Where a number of posts are required to be driven, all within range of the guide and base frame, all that is required by a user is to adjust and position the guide upon the base frame to allow the monkey, when at its lowermost position, to engage the next post requiring driving. The monkey may then be raised and allowed to fall to engage and provide penetrative force to a post.

Aspects of the present invention have been described by way of example only and it should be appreciated that modifications and additions may be made thereto without departing from the scope thereof as defined in the appended claims.

P:\WPDOCS\GRS\SPECI\78256233.doc 22/7/03

Claims (4)

1. A post driver comprising: a base frame, attachment means for attachment to a towing vehicle, a guide mounting a weight, and means for raising and releasing said weight on said guide wherein said guide is mounted to said base frame in a manner which enables the position of the guide to be adjusted in relation to said base frame.

2. A post driver as claimed in claim 1, wherein the base frame is substantially planar and the position of the guide is adjustable in the plane of the base frame.

3. A post driver as claimed in claim 1 or claim 2, wherein the position of said guide is adjustable on an arcuate or semi-circular rail of said base frame.

4. A post driver as claimed in any one of claims 1 to 3, wherein said rail is in the form of a channel which provides support for a gearing or chain rack, and wherein a motor drives a gear pinion or sprocket which engages with said gearing or chain rack to provide for positional adjustments of said guide about the base frame. A post driver as claimed in any one of claims 1 to 4, wherein a pivotable arm supports and allows for movement of said guide with respect to said base frame, and wherein said arm is extendable or has telescopic capability, or P:\WPDOCS\GRS\SPECI\78256233.doc 22f7/03 wherein said guide is telescopic and includes an outer housing and an inner housing wherein said outer housing moves relative to a static inner housing. DATED this 22nd day of July, 2003. Tony Graeme White AND Deborah Ellen White By Their Patent Attorneys DAVIES COLLISON CAVE P:\WPDOCS\GRS\SPECI\78256233.doc 2207/03