AU2012268905B2

AU2012268905B2 - Post Driver

Info

Publication number: AU2012268905B2
Application number: AU2012268905A
Authority: AU
Inventors: John Mowatt Bryce
Original assignee: Individual
Current assignee: Individual
Priority date: 2012-12-31
Filing date: 2012-12-31
Publication date: 2016-04-14
Anticipated expiration: 2032-12-31
Also published as: AU2012268905A1

Abstract

Title of the invention: Post driver Abstract Title: A post driver with positioning means A post driver 5 has a frame 20, 25 with attachment means 15a, 15b, 15c, which may be used to mount the driver to a tractor, a mast 10 supported by the frame and adapted to allow a weighted member (120, figure 10) to travel up and down. There are at least two independently operable hydraulically operated legs 50, 55. There are side shift means 125a, 125b, which may be pistons, to enable positioning of the mast to be optimised for alignment with a post to be driven. There may also be backshift means 80a, 80b. The mast is provided on an opposite side of the frame to the attachment means. A second invention discloses a post driver which has back shift means. The mast may be located at a centre of the post driver in a lateral direction.

Description

1 POST DRIVER FIELD OF INVENTION The present invention relates to post drivers for driving, for example, posts into the ground. The present 5 invention also relates to a method of using said post drivers. BACKGROUND OF INVENTION Post drivers usually consist of a vertical pillar 10 column or mast for guiding a falling weight that is lifted by hydraulic power from, for example, a tractor on which the post driver is mounted. A small ram, working through a leverage system, may pull a rope over a pulley at the top of the pillar or column so as to lift the 15 weight in order that it may then be dropped onto a post. However, existing post drivers suffer from a number of disadvantages. For example, existing post drivers have difficulty in driving posts in hard hill country. In addition, to properly align existing post drivers, a 20 connected tractor needs to be moved backwards and forwards to correctly position the post driver. Such movement for the tractor can lead to excessive clutch wear. It is also difficult to obtain small movements of the tractor on uneven ground. 25 It is known to provide a post driver comprising a frame having attachment points for mounting the frame to 2 a vehicle such as a tractor. The mast is mounted on a side face of the frame in the vehicle width direction and a counterbalance is mounted on an opposing side face of the frame in a vehicle width direction. In this way, in 5 use, the vehicle can be driven alongside a fence line and stopped at positions where it is desired to drive in a post, whereupon, the post can he driven in using the weight on the side mounted mast. In this way, manoeuvring and reversing of the vehicle is reduced. 10 It is an object of at least one aspect of the present invention to obviate or mitigate at least one or more problem with the prior art, or to at least provide a useful alternative. It is a further object of at least one aspect of the 15 present invention to provide a post driver that provides improved driving power and manoeuvrability. It is a further object of at least one aspect of the present invention to provide a more compact and/or lighter and/or less complex and/or less expensive post 20 driver. SUMMARY OF INVENTION According to a first aspect of the present invention there is provided a post driver comprising: 25 a frame, the frame comprising attachment means for mounting the post driver; 3 a mast supported by the frame and adapted to allow a weighted member to travel up and down; at least one tilt mechanism configured to rotate the post driver and/or mast in a lateral direction, wherein 5 at least one of the tilt mechanisms comprises at least two independently operable hydraulically operated legs configured such that at least one leg is extendable and/or at least one other leg is retractable so as to tilt the post driver; and 10 positioning means for enabling the position of the mast to be optimised and adapted for alignment with a post to be driven; wherein the positioning means comprises a side shift configured to move the mast in a lateral direction; 15 the mast is provided on an opposite side of the post driver to the attachment means; and the frame comprises a laterally extending mast support member, and the mast comprises or is mounted on a mast carriage, the mast carriage being slidable or 20 moveable on the support member. The positioning means may also include a backshift configured to move the mast in a longitudinal direction. A combination of tilt means for tilting the mast and/or post driver in a lateral direction and a plurality 25 of laterally spaced independent hydraulic legs provides particular advantages. In particular, without the 4 independently operable hydraulic legs, when tilting the mast, the frame may be rotated and moved, through an arc such that the post driver sits either on the left or right corner of the main frame. In addition, there may be 5 some degree of motion or looseness in the support of the post driver, for example, due to deflection or flexing in the pneumatic tyres of the vehicle upon which the post driver in mounted. Additionally, there may be multiple movable joints, with ten movable joints not uncommon, 10 between the vehicle and the post driver. Each joint may have a tolerance or inherent looseness, which may multiply up over each joint. This motion of the post driver may lead to problems when driving in a post. The combination of independently operable hydraulic 15 legs with the tilt means allows each leg to be extended by the height required to support the post driver, regardless of the angle of tilt. In this way, the post driver may be operated in a stable manner, regardless of the angle of tilt or any looseness in the coupling. This 20 extra stability may allow the post driver to be lifted higher and/or tilted further for example. It will be appreciated that a longitudinal direction is a direction extending rearwardly of the vehicle and/or in a direction from an end of the post driver where the 25 attachment means are provided to an end of the post driver where the mast is provided. The lateral direction 5 is generally perpendicular to the longitudinal direction, for example in a horizontal direction, which may be a left and right in the vehicle and/or post driver. The backshift may be configured to move the mast 5 toward and/or away from the attachment means. In use, the backshift may be configured to move the mast toward and/or away from a vehicle attached to the post driver via the attachment means. By providing the mast on the opposite side of the 10 frame to the attachment means a vehicle or other apparatus upon which the post driver is mounted may be operable as the counterbalance, which may provide stable and safe operation of the post driver and may minimise the weight and number of components of the post driver 15 and provide a more compact system. The attachment means may comprise means for mounting the post to driver to a vehicle, such as a tractor or the like, and/or an articulated hydraulic arm or other device or structure to which it is desired to mount the post 20 driver, such as diggers, loaders and telehandlers. The post driver may be configured such that the vehicle, device or structure mounts to the post driver along a generally longitudinal direction of the post driver. The mast may be located or locatable at a centre of 25 the post driver in a lateral direction which, in use, may be a vehicle width direction. For example, the mast may 6 be locatable at the centre of the post driver in a lateral direction using the side shift. In this way a stable transport and/or operation position may be achieved. 5 The mast may be located or locatable in a position on the frame opposite at least part of the attachment means. The side shift and back shift may allow the mast to be moved respectively laterally and longitudinally 10 without having to move the frame itself and/or a connected vehicle. Typically, the back shift and side shift are at substantially 90 to one another thereby allowing the mast to be moved over a full range of directions i.e. side to side and front to back. This has 15 the specific advantage that the position of the mast can be altered and adjusted to obtain optimal alignment with a post. The back shift and side shift may be hydraulically operated thereby allowing easy and accurate adjustments of the position of the mast to be made. The 20 back shift and side shift may have any suitable range of travel such as about 100 to 1,000 mm or preferably about 600 mm for the side shift and 100 mm to 1,000 mm or preferably about 300 mm for the back shift. Telescopic members may be used to obtain the movement for the side 25 shift and/or back shift.

7 The frame may comprise at least a first frame section and a second frame section. The first or second frame section may be movable relative to the other of the first or second frame section. 5 The relative movement of the first and second sections may he under the action of backshift drive means. The backshift drive means may comprise extendable members, which may be telescopic, such as hydraulic backshift rams. The first frame section may comprise the 10 attachment means. The mast may be mounted or mountable on the second frame section. The first and second frame sections may be configured for relative motion such that at least part of the first frame section and at least part of the second frame section are movable together and 15 apart, which may be in a longitudinal direction of the post driver. In this way, the mast may be movable closer and further away from the attachment points to thereby provide a backshift mechanism. One of the first or second frame sections may 20 comprise hollow backshift outer members and the other of the first or second frame sections may comprise backshift inner members which may be slidably located or locatable within the backshift outer members. The backshift inner and outer members may be in a telescoping arrangement. 25 The backshift inner members may be hollow. The backshift drive means may be located or locatable within the outer 8 and/or inner backshift members. Wear pads may he provided between the inner and outer backshift members, for example, between the outer top wall of the backshift inner member and the inner top wail of the back shift 5 outer member. The wear pads may preferably he static wear pads but may instead be rotary wear pads. The second frame section may comprise a mast support member. The mast support member may comprise a cross beam or runner, which may extend laterally. 10 The mast may comprise or be mounted or mountable on a mast carriage. The mast carriage may be slidable or movable on the support member, for example, in a lateral direction Bearings may be provided between the mast: carriage and the mast support member. The side shift may 15 comprise a non-telescoping side-shift. The side shift may comprise at least one side shift driver for moving the mast in a lateral or width wise direction of the post driver, which may be a lateral direction perpendicular to a direction in which the 20 attachment means and first frame lie. The side shift driver(s) may be operable to move the mast laterally to at least one side of the centre of the post driver and preferably to both sides of the centre of the post driver in a lateral direction. 25 One or more side shift drivers may he mounted between the mast and/or mast carriage and the second 9 frame section. A first side shift driver may be mounted to a first portion of the second frame section. A second side shift driver may he mounted to a second portion of the second frame section. The first portion of the second 5 frame may be on an opposite side of the mast to the second portion. In this way, the mast carriage may be slidable laterally along the mast support member under the action of the one or more side shift drivers. Preferably, the at least one side shift driver may 10 comprise at least one extendable member, which may be telescopic, such as a side shift hydraulic ram. Two side shift drivers may be provided. At least one side shift driver may be configured for motion in a substantially opposite direction to at least one other 15 side shift driver. The opposing side shift drivers may be arranged in a piggy back configuration, which may comprise one end of the at least one side shift driver being mounted to the mast and/or mast carriage adjacent and above an end of the at least one other side shift 20 driver. However, it will be appreciated that the opposing side shift drivers may be mounted aligned end to end. The side shift drivers may he mounted in a pull me - push you arrangement, for example, when a chamber of one opposing side shift driver is being pressurised, a chamber of the 25 opposing side shift driver is depressurised and vice versa.

10 The side shift driver(s) may be single action, i.e. they are configured to substantially apply a force in only one direction. However, although a pair of side shift drivers are 5 described above2 it will be appreciated that optionally only one side shift driver may be provided, it will also be appreciated that double action (i.e. adapted to substantially apply a force in two directions, such as expanding and contracting) may be used. 10 Each side shift driver may comprise a hydraulic ran having at least two stages, for example, a double action ran. The hydraulic ram may be a telescoping hydraulic ram, which may have at least two telescoping stages or ranges of movement. 15 A first stage of movement may comprise a first telescoping member of the ran telescopically moving relative to a second telescoping member of the ram. A second stage of movement may comprise the second telescoping member telescopically moving relative to a 20 third telescoping member of the ram. In a preferred but not essential configuration, two or more stage hydraulic rams are provided in an opposing configuration, wherein the rams are single acting rams and a first of the opposing rams is operable to 25 respectively contract or expand the second of the opposing rams whilst the first ram is being expanded or 11 contracted respectively, This configuration results in an improved side shift motion, particularly having a larger range of travel. This configuration may provide a compact side shift 5 mechanism having a large range of motion. In an optional embodiment, the side shift may comprise a trunion arrangement. In an optional embodiment, the mast may comprise a screw thread member and the side shift drive means may comprise screw 10 engagement means coupled to the second frame section, such as a cog or complimentary screw threaded member, for engaging and actuating the screw thread member to thereby laterally move the mast The side shift drive means may comprise a motor, such as an oil motor, for moving the 15 screw engagement means and thereby the screw thread member and mast. Typically, the mast may be telescopic up to any suitable length such as! for example, allowing up to about ten foot posts and ground anchors to be driven in. 20 The telescopic mast has all the advantages of a tall fixed mast thereby offering maximum impact and yet also allowing the post driver to be moved and transported in a compacted configuration. Preferably, the weighted member may be a hitting 25 hammer which may have a weight of about 100 to 1,000 kilograms or preferably about 400 to 600 kilograms. The 12 weight of the weighted member may be adapted for different situations e.g. hardness of the ground. By providing a plurality of legs, the apparatus may have a stable configuration during use, For example, two 5 or more supporting legs on skid plates may be used. The skid plates provide a stable footing for the post driver. Independently hydraulically operable legs allow the apparatus to operate on uneven ground and/or stabilise the post driver, as described above. The legs may be 10 mounted on the first frame section. The legs may be operable using one or more hydraulic rams, which may be driven from a hydraulic pressure feed and/or controller via hydraulic pipes A safety valve may be provided between the hydraulic pressure feed and the 15 hydraulic rams, wherein the safety valve may be adapted to shut/close in the event that the hydraulic ram, feed or pipes are depressurised, such as being suddenly or rapidly depressurised, e.g. due to a leak or burst. In this way, the pressurised line on the other end of the 20 safety valve from the leak remains at least partially pressurised, which may prevent the hydraulic legs from unexpectedly retracting. Preferably, the safety valve is located on the hydraulic pressure feed further towards the hydraulic ran 25 than towards a pressure source. The safety valve may preferably by incorporated with, located on, adjacent to 13 or proximate to the hydraulic ram. In this way, a proportion of the hydraulic system in which leaks or bursts could occur and where the safety valve could still protect the pressure supplied to hydraulic ram would be 5 maximised. At least one arid preferably each of the hydraulic rams of the post driver may be provided with a safety valve, which may be a safety valve as described above. For example, safety valves could be provided in, on, 10 adjacent to or proximate to a hydraulic tilt ram, a hydraulic ram for extending/contracting the mast and/or hydraulic rams for operating the back and/or side shifts. The attachment means may comprise means for allowing arcuate motion of the post driver in a plane 15 substantially perpendicular to a ground surface and/or a substantially vertical plane. The attachment means may provide a plurality of attachment points between the post driver and the vehicle. 20 Typically, the post driver may comprise a plurality of attachment means, for example, first, second and third attachment means for directly or indirectly attaching the post driver to first, second, and third attachment portions of the vehicle respectively.

14 The first and/or second attachment portions may be located near a bottom portion of a rear chassis of the vehicle. The third attachment portion may be located near a 5 rear chassis portion of the vehicle in an elevated position relative to the first and/or second attachment portion. Typically, the first and/or second attachment means may be attachable to the respective first and second 10 attachment portions of the vehicle via respective first and second support arms extending from and/or secured to a bottom portion of the rear chassis of the vehicle, and typically also respective first and second attachment members for attaching the respective first and second 15 support arms to the respective first and second attachment means of the post driver. Typically, the third (or upper) attachment means may be attachable to the third (or upper) attachment portion of the tractor via a top or third extendable attachment 20 member between the third attachment portion of the tractor and the third attachment means of the post driver. By such provision, the post driver may be pivoted relative to an imaginary axis extending between the first and second attachment members, i.e. in a 25 vertical plane and/or a plane perpendicular to the 15 ground, in use, by operation of the third extendable attachment member. The top or third extendable attachment member may comprise, e.g., a hydraulic ram, or a mechanically 5 extendable member. Typically, the third extendable attachment member may be secured to the third attachment portion of the tractor and/or the third attachment means of the post driver by fixing means such as a knuckle link, perforated 10 plates and pins or the like. The fixing means may comprise a plurality of fixing points, for example, a plurality of holes in a perforated plate, which may provide a range of fixing angles. Optionally, the first and/or second attachment 15 members may comprise movable or pivotable attachment members, which may comprise a ball joint. In one embodiment, the third (or upper) extendable attachment member may he pivotahle relative to the third attachment portion of the tractor and/or to the third 20 attachment means of the post driver. Typically, the third extendable attachment member may be secured to the third attachment portion of the tractor and/or to the third attachment means of the post driver by at least one pivotable member. 25 In another embodiment, the attachment of the third extendable attachment member to the third attachment 16 portion of the tractor and/or to the third attachment means of the post driver may comprise e.g. a bracket provided with e.g. guiding grooves to allow for such arcuate motion. 5 In another embodiment, the attachment of the third extendable attachment member to the third attachment portion of the tractor and/or to the third attachment means of the post driver may exhibit a degree of looseness sufficient to allow for arcuate motion. 10 Preferably, the at least one third pivotable member may comprise a ball provided within a receiving portion of the third extendable member, which may be at or near an end nearest the third attachment portion of the tractor and/or the third attachment means of the post 15 driver. Conveniently, the receiving portion may be arranged to allow for rotational and/or pivotal motion of the ball, and may be arranged to prevent disconnection of the ball from the third extendable member. 20 The third telescopic member may comprise a two stage hydraulic link. By providing a two stage third hydraulic member, additional travel may be provided, which may he used to get the travel required to get the mast vertical on sloping ground. Furthermore, with at least one of the 25 independent hydraulic legs extended so that the post driver is raised, some of the extension of the third 17 telescopic member may be used to accommodate the extension of the legs. By using a two stage hydraulic link, extra travel is provided, which may be used to align the mast, even when the some of the extension is 5 taken up by accommodating the hydraulic leg extension. According to a second aspect of the present invention is a post driver comprising: a frame, the frame comprising attachment means for mounting the post driver; 10 a mast supported by the frame and adapted to allow a weighted member to travel up and down; and positioning means for enabling the position of the mast to be optimised and adapted for alignment with a post to be driven; and 15 the mast is located or locatable centrally of the post driver in a lateral direction. By making the mast located or locatable centrally in a lateral direction (e.g. a direction perpendicular to the direction in which a vehicle mounts to the post 20 driver), the mast may be more stably configured. The mast may be movable laterally to both sides of the centre of the post driver in a lateral direction. According to a third aspect of the present invention there is provided a post driver comprising: 25 a frame, the frame comprising attachment means for mounting the post driver and a mast support member; 18 a mast adapted to allow a weighted member to travel up and down; and wherein, the mast is mounted on or integral with a mast carriage and the mast carriage is movably mounted on 5 the mast support member. The mast carriage may be slidably mounted on the mast support member. The mast support member may extend in a lateral direction. The mast support member may comprise a beam, 10 which may comprise a hollow beam such as a box section beam. The mast carriage may comprise bearings and/or wheels and/or rollers. The mast carriage may he movable by one or more extendable members, which may comprise a 15 hydraulic piston, and preferably comprises two opposing pistons. According to a fourth aspect of the present invention there is provided a post driver comprising: a frame, the frame comprising attachment means for 20 mounting the post driver; a mast supported by the frame and adapted to allow a weighted member to travel up and down; and positioning means for enabling the position of the mast to be optimised and adapted for alignment with a 25 post to be driven.

19 The positioning means may comprise side shift means, which may be configured to move the mast in a lateral direction of the post driver. The post driver may comprise at least two 5 independently operable hydraulically operated legs. The post driver may comprise tilt means for tilting the mast and/or post driver, for example, in a lateral direction. The mast may be provided on an opposite side of the 10 frame to the attachment means. The positioning means may comprise back shift means, which may be configured to move the mast in a forwards/backwards or longitudinal direction of the post driver or towards and away from the attachment means. 15 The frame may comprise a first frame section, which may comprise or be provided with at least one and preferably all of the attachment means. The mast may be movable or slidable relative to the first frame section. The frame may comprise a second frame section or mast 20 support for supporting the mast. The second frame section or mast support may be movably or slidably mounted to the first frame section. The side shift may comprise the relative movement or sliding of the first and second frame sections. 25 One of the first or second frame sections may comprise at least one hollow member for receiving at 20 least one corresponding slidable member of the other of the second or first frame sections. Relative movement of the first and second frame sections may he hydraulically operable, for example, using one or more hydraulic rams 5 mounted between the first and second frame sections. The post driver may comprise two or more legs. At least one leg may be adjustable. At least one leg may be hydraulically adjustable. The legs may be independently adjustable. At least one leg may be fixed. At least one 10 leg may be slidably receivable within a hollow member of the frame, which may be an upright member. The attachment means may comprise at least two and preferably three attachment means. The attachment means may be adapted to pivotably couple to a vehicle, 15 hydraulicly operated arm or other supporting apparatus. The attachment means may comprise or be configured to receive a ball of a ball joint or may comprise at least part of a ball joint. The post driver may comprise at least one and 20 preferably at least two tilt mechanisms, which may be configured to tilt the post driver through a vertical tilt plane. At least one and preferably each tilt mechanism may be configured to rotate the post driver and/or mast in a lateral direction, which may be 25 perpendicular to the direction in which the post driver 21 couples to the vehicle, arm or other supporting apparatus. At least one of the tilt mechanisms may comprise a movable or slidable tilt member, which may be mounted on 5 the frame so as to be relatively movable or slidable therewith. The slidable member may comprise or be provided with at least one of the attachment means for coupling the post driver to a vehicle, arm or other support apparatus. 10 The movable or slidable tilt member may be hydraulically movable or slidable relative to the frame. The movable or slidable tilt member may be movably or slidably mounted to a member of the frame, such as an upright member. The movable or slidable member may be 15 movable or slidable in a vertical direction of the frame. The post driver may comprise a hydraulic tilt ram, which may be provided between the slidable member and the frame, for example, in parallel with the slide direction of the slidable member, which may be substantially 20 vertical, in use. The hydraulic tilt ram may be configured to slide the slidable member relative to the frame. The post driver may comprise at least one further attachment means, which may be comprised in or mounted to 25 the frame, for example, on another upright member of the frame. The further attachment means may be spaced 22 laterally from the attachment means of the tilt member. The further attachment means may comprise a pivoting or pivotable attachment means, such as a ball joint. In this way, since one attachment means is provided 5 on the tilt member so as to be movable or slidable relative to the frame, whilst another attachment means is fixed relative to the frame, operation of the hydraulic tilt ram moves the frame relative to the slidable member so as to tilt, pivot or rotate the post driver around the 10 pivotable joint of the attachment means that is fixed relative to the frame. Since the attachment means that is fixed relative to the frame (and preferably also the attachment means provided on the tilt member) is coupled to the vehicle via a pivotable joint, such as a ball 15 joint, the post driver is free to rotate around the fixed attachment means. With the attachment means of the slidable member being laterally spaced from the attachment means of the frame, the tilting of the frame (and thereby the mast) is 20 in a lateral plane. The tilt mechanism may be a primary tilt mechanism. The independently adjustable legs may comprise or form a secondary tilt mechanism and/or a machine stabiliser including height control.

23 The secondary tilt mechanism may comprise extending at least one leg and/or retracting at least one other leg in order to tilt the post driver. The mast may be provided with a support leg at the 5 bottom of the mast. The support leg may be extendable and retractable. The post driver of the fourth aspect may comprise one or more features described in relation to any of the first to third aspects. The post driver of any of the 10 first to third aspects may also comprise one or more features described in relation to the fourth aspect. According to a fifth aspect of the invention is apparatus comprising a vehicle provided with or having mounted on it a post driver according to any of the first 15 to fourth aspects of the invention. According to a sixth aspect of the present invention there is provided a method of using the post driver according to any of the first to fourth aspects of the vehicle of the fifth aspect in driving a post into the 20 ground. Features described in relation to any of the above aspects of invention may also be optionally applicable to any other of the above aspects of invention. Method features analogous to any described apparatus features or 25 vice versa are also incorporated herein.

24 BRIEF DESCRIPTION OF DRAWINGS Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings in which: 5 Figure 1 is a front or vehicle mounting end view of a. post driver according to an embodiment of the present invention; Figure 2 is a rear or mast end view of the post driver shown in Figure 1; 10 Figure 3 is a side view of the post driver shown in Figures 1 and 2; Figure 4 is a top view of the post driver shown in Figures 1 to 3; Figure 5 is a perspective view of a frame for use in 15 the post driver of Figures 1 to 4; Figure 6 is a perspective view of the frame shown in Figure 5; Figure 7 is a side view of the frame shown in Figures 5 and 6; 20 Figure 8 is a side view of the post driver of Figures 1 to 4 mounted to a vehicle; Figure 9 is a side view of the post driver of Figures 1 to 4 in a backshifted configuration and mounted to a vehicle; 25 Figure 10 is a portion of a mast for use with the post driver of Figures 1 to 4; 25 Figure 11 is a rear view of the post driver of Figures 1 to 4 mounted to a vehicle; Figure 12 is a rear view of the post driver of Figures 1 to 4 in a first sideshifted configuration and 5 mounted on a vehicle; Figure 13 is a rear view of the post driver of Figures 1 to 4 in a second sideshifted configuration and mounted on a vehicle; Figure 14 is a rear view of the post driver of 10 Figures 1 to 4 in a configuration wherein at least one of the independently operable hydraulic legs has been extended; Figure 15 is a side detail view of a part of a post driver according to an embodiment of the present 15 invention; Figure 16 is a detail view from the rear and side of a part of the post driver of Figure 15; and Figure 17 is a rear view of the post driver of Figures 15 and 16 is use. 20 DETAILED DESCRIPTION OF DRAWINGS Figures 1 to 4 show a mountable post driver 5 having a mast 10 mounted on a side of the post driver 5 opposite to a side of the cost driver 5 that comprises means for 25 mounting the post driver 15a, 15b, 15c. The post driver comprises a first frame section 20 and a second frame 26 section 25, which are shown in detail in Figures 5 to 7. Throughout the Figures, the mast may be shown in a generalised or partial form and it will be appreciated that the mast optionally comprises features such as at 5 least one of a hammer, telescoping mast sections, one or more pulleys, guide rails, hitting cap and the like that are known in the art, for example. The first frame section 20 is formed from hollow steel box section members and comprises upper 30 and 10 lower 35 cross beams extending between left 40 and right upright sections. Each of the left 40 and right 45 upright sections contain respective left 50 and right 55 legs, which are slidably received within the left 40 and right 45 upright sections,, The left 50 and right 55 legs 15 are independently hydraulically operable and may be adjusted to any required level, for example to compensate for the ground being sloping or to tilt the post driver. Each leg is provided with a skid 60a, 60b in order to prevent the leg 50, 55 becoming bogged down in infirm 20 ground. The upper cross beam 30 of the first frame section 20 is provided with an upper attachment portion 15c at the centre of the upper cross beam 30 in a lateral direction. The lower cross beam 35 is provided with left 25 15a and right 15b lower attachment portions, the left 15a and right 15b lower attachment portions being 27 respectively laterally displaced relative to the upper attachment portion 15c, such that the upper attachment portion 15c lies above and between the left 15a and right 15b lower attachment portions in a triangular 5 arrangement. The upper 15c, lower left 15a arid lower right 15b attachment portions each comprise a pair of plates mounted in parallel to each other, the plates being welded to the appropriate upper or lower cross beam and extending therefrom in a direction away from the 10 second frame section. Each plate comprises one or more holes for receiving a pin in order to mount the post driver 5. Provision of more than one hole allows a variety of mounting options. The first frame section 20 is provided with two 15 parallel hollow box section tubular backshift outer members 65a, 65b rigidly mounted or formed between the upper 30 and lower 35 cross beams of the first frame section 20. The backshift outer members 65a, 65b, for example, welded to or integral with an upper surface 70 20 of the lower cross beam 35 and to a lower surface 75 of the upper cross beam 30. The backshift outer members 65a, 65b extend in a direction perpendicularly to both the cross members 30, 35 and the upright members 40? 45 of the first frame section 20. 25 Backshift inner members 80a, 80b are slidably mounted within respective backshift outer members 65a, 28 65b. An end of each backshift inner member 80a, 80b that is positioned furthest from the end of the post driver 5 that comprises the means for mounting 15a, 15b, 15c is attached to the second frame section 25, for example by 5 being welded to upper 85a and lower 85b cross members of the second frame section 25. The second frame section 25 is formed from tubular steel box section members and comprises at least upper 85a and lower 85b cross beams disposed between left 95a 10 and right 95b upright members. Hydraulic backshift rams 90a, 90b are provided to act between each of the respective inner 80a, 80b and outer 65a, 65b backshift members. In this way, the second frame section 25 is movable towards and away from the 15 first frame section 20 by the relative sliding motion of the inner 80a, 80b and outer 65a, 65b backshift members under the action of the hydraulic backshift rams 90a, 90b, as shown in Figures 8 and 9, in this case, in a direction that is perpendicular to both the cross members 20 30, 35, 85a, 85b and the upright members 40, 45, 95a, 95b of the first 20 and second 25 frame sections. One or more, and in this case two, balancing legs 100a, 100b are provided extending from the second frame section 25 and extend in a longitudinal direction 25 perpendicular to both the upright 95a, 95b and cross members 85a, 85b and in a direction away from the first 29 frame section 20. The end of the balancing legs are provided with downwardly extending feet 105a, 105b such that the post driver 5 may be sat on the ground resting on the left and right independent hydraulic legs 60a, 60b 5 of the first frame section 20 in a fully retracted configuration and the feet 105a, 105b of the balancing legs of the second frame portion 25. This configuration with balancing legs 100a, 100b extending in a direction away from the first section 20 increases the stability of 10 the post driver 5 when resting on the ground. A mast carriage 110 is movably or slidably mounted on the top cross beam 85a of the second section 25. A mast 115 is mounted on or integral with the mast carriage, such that the mast is provided on an opposite 15 side of the second frame section to the first frame section, i.e. on a side of the post driver opposite to the attachment portions. The mast 115 comprises a hitting hammer 120 (shown in Figure 10) that is slidable up and down the mast 115 in use to drive in a post, support or 20 the like. The mast 115 may take the form of any suitable mast configuration known in the art, for example, the double pulley telescoping mast described in GB2441071B, which is hereby incorporated by reference, a portion of which is shown in Figure 10. 25 The mast carriage 110 comprises a vertically extending piston attachment rod 120. A pair of opposing 30 sideshift pistons 125a, 125b are provided between the second frame section 25 and the mast carriage 110 for moving the mast carriage 110 on the top cross beam. The first opposing sideshift piston 125a is provided between 5 the left upright member 95b of the second frame section and the piston attachment rod 120 of the mast carriage and the second opposing sideshift piston 125b is provided between the right upright member of the second frame section and the piston attachment rod of the mast. The 10 opposing sideshift pistons 125a, 125b are arranged in a piggy-back configuration, i.e. one of the opposing sideshift pistons 125b is positioned to be higher than the other opposing piston 125a such that the end of the upper opposing piston 125b that is connected to the 15 piston attachment rod 120 sits immediately above an end of the other opposing piston 125a, 125b. In this embodiment, two single action pistons are used, i.e. each piston is operable to apply force in only one direction, although it will be appreciated that one or more than one 20 double action pistons (i.e. operable to apply a force in two opposing directions) may be used instead. The opposing pistons are telescoping rams having two stages, i.e. the rams comprise a first inner telescoping member slidably arranged within an outer telescoping member and 25 a second inner telescoping member slidably arranged 31 within the first inner telescoping member. Thereby, a ram having two distinct movement stages is provided. As shown in Figures 11 to 13, the first opposing piston 125a is operable to push the mast 115 away from 5 the left upright member 95a and toward the right upright member 95b, i.e. in a left to right when viewed from the front of the post driver 5 or widthwise or lateral direction (as shown in Figure 13), whilst the second upright piston 125b is operable to push the mast 115 away 10 from the right upright member 95b towards the left upright member 95a, i.e. right to left when viewed from the front of the post driver or widthwise or lateral direction (as shown in Figure 12). In this way, the opposing sideshift pistons 125a, 15 125b may be utilised in a "pull me push you" fashion, wherein, when one side shift piston 125a, 125b is pressurised with hydraulic fluid, it acts to move the mast carriage 110 and hydraulic fluid is evacuated from the other opposing sideshift piston 125b, 125a, to move 20 the mast carriage 110 and thereby the mast 115 about a position in the centre of the top cross beam 85a of the second frame section 25 towards the right or left side of the cross beam 85a by appropriate activation of a selected opposing hydraulic sideshift piston 125a, 125b. 25 In this way, a controlled and smooth lateral movement of the mast 115 is achieved. Furthermore, a wide range of 32 lateral motion is provided, the range of motion extending to both sides of the centre of the post driver 5 in a widthwise or lateral direction. In addition, the use of two opposing pistons 125a, 125b in this manner provides a 5 compact and reliable means for lateral movement. Since the lateral or sideways range of)tion of the mast is at the widthwise centre of the post driver 5, greater balance and stability may be achieved. By providing the mast 115 on a side of the post 10 driver 5 opposing the vehicle attachment means 15a, 15b, 15c, in use, a lighter and more compact but stable post driver can be provided, since the vehicle to which the post driver is attached may act as a counter balance, which may eliminate or reduce the need for a dedicated 15 counterbalance. The post driver 5 may be attached to a vehicle or other apparatus by any means known in the art, for example, by a conventional 3 point linkage, comprising two lower attachment points and an upper attachment 20 point. The post driver may be attached via attachment means that allow a degree of pivotable motion, such as ball joints. The two lower attachment points may be on the end of respective first and second support arms 160a, 160b. 25 The post driver may he attached to an upper attachment point 150c of the vehicle or apparatus via a 33 top shift extending member 155c, such as a telescoping hydraulic ram. The distal end of the top shift extending member 155c is attached to the vehicle near a rear chassis portion of the vehicle and in an elevated 5 position 150c relative to the first and second support arms 160a, 160b. In this way, the top shift extending member 155c is operable to pivot the post driver 5 relative to an imaginary axis extending between the ends of the lower right and lower left support arms to which 10 the post driver is mounted, which may comprise pivoting in a generally vertical plane and/or a plane substantially perpendicular to a ground surface 170. In this embodiment, the top shift extending member 155c is secured to the third attachment portion 150c of 15 the tractor and to the upper attachment portion of the post driver 15c by means of a bracket and pin or knuckle link. Advantageously, the top shift extending member 150c may be a two stage hydraulic ram having a first inner 20 telescoping member slidably arranged within an outer telescoping member and a second inner telescoping member slidably arranged within the first inner telescoping member. Thereby, a two-stage top shift extending member 150c is provided. In this way, enough travel may be 25 provided in the top shift in order to accommodate vertical alignment of the mast by arcuately rotating the 34 post driver in a vertical plane and also have sufficient travel to also accommodate operation of the hydraulic legs, for example, as shown in Figure 14. As detailed above, movement of the second frame 25 5 section relative to the first frame section 20 by sliding of the inner backshift slide members 80a, 80b of the second frame section 25 in the outer backshift members 65a, 65b of the first frame section 20 under the action of the backshift hydraulic rams 90a, 90b, the mast is 10 positionable in a forward/backward direction, as shown in Figure 8 and 9. By mounting the mast 115 On the mast carriage 110, the mast is slidable under the action of the opposing side shift pistons 125a, 12Sb in a lateral (left/right) direction and to both sides of the centre of 15 the post driver in a lateral direction, as shown in Figures 11 to 13. Furthermore, extension and/or retraction of the top extension means 155c allows the post driver 5 to be pivoted in a vertical arc around the lower ball joints 135a, 135b. 20 Operation of the independently hydraulically operated legs allows raising, lowering and side to side tilting of the post driver, as shown in Figure 14. In this way, further axes of motion are provided, which may be especially suitable for aligning the post driver on 25 slopes.

35 Therefore, a compact and stable post driver 5 that has a wide range of mast position adjustment options is provided. This is particularly beneficial on a front or rear facing post driver, as additional vehicle 5 manoeuvring may be require to "back" the vehicle/post driver up to the post relative to a post driver having a side facing mast. The wide range of alignment options provided by the provision of backshift, sideshift, arcuate motion and/or independent hydraulic operation of 10 the legs allows the mast to be positioned and aligned quickly and simply whilst minimising movement of the vehicle. In an alternative embodiment, the mast slide member 110' may comprise at least one screw member 175 and the 15 post driver 5 is provided with a motor 180, such as an oil motor for turning a cog 185 or screw for engaging with and actuating the screw member 175 to thereby move the mast slide 110'. In a further alternative embodiment, a trunion may be used to actuate the mast 20 slide. An alternative or additional embodiment of the invention is illustrated in Figures 15 to 17. These figures show a post driver 1000 having a primary tilt mechanism 1005 and a secondary tilt mechanism 1010 that 25 also acts as a machine stabiliser and height control mechanism.

36 The post driver 1000 shown in Figures 15 to 17 comprises a frame 1015 for supporting a mast 1020, a hammer 1025 slidably mounted on the mast 1020 and driving means (not shown) for slidably actuating the hammer 1025 5 up and down the mast 1020. The post driver 1000 is mountable to a vehicle 1030 or other support structure via a three point linkage having an upper attachment means 1035a and two lower attachment means 1035b, 103Sc. The lower attachment 10 means 1035b 1035c are configured to be pivotable and form, for example ball joints, as described above. A first lower attachment means comprises 1035c a ball 1040c attached by a spindle 1045c that passes through apertures in each of two parallel fixing plates 15 1050c. The spindle 1045c is secured in position with a fixing pin. The parallel fixing plates 1050c of the first lower attachment means 1035c are fixedly mounted on a first upright section 1055 of the frame 1015. A second lower attachment means 1035b comprises a 20 ball 1040b attached via a spindle 1045b to two apertured parallel plates 1050b, as in the first lower attachment means 1035c. The apertured parallel plates 1050b are fixed to a movable slide 1060 such that the second lower attachment means 1035b is laterally spaced from the first 25 lower attachment means 1035c.

37 The balls 1040b 1040c of the first and second lower attachment means 1035b, 1035c may be received or receivable within correspondingly shaped receiving portions 1065b, 1065c coupled with the vehicle 1030 or 5 other support structure so as to be pivotable therein. The movable slide 1060 comprises a hollow box section mounted so as so be slidably movable up and down a second upright section 1070 of the frame 1015, such as an outer box of a hydraulic leg. The slide 1060 is 10 movable under the action of a hydraulic tilt ram 1075 that extends substantially vertically between the slide 1060 and a fixing point on the second upright section 1070 of the frame 1015. In this wayl by extending or contracting the 15 hydraulic tilt ram 1075, the second upright section 1070 of the frame 1015 is slidable relative to the slide 1060 comprising the second lower attachment means 1035b. As the position of the first lower attachment means 1035c is fixed relative to the frame 1015, extending or retracting 20 the hydraulic tilt ram 1075 causes the frame 1015 to rotate in a lateral direction through a vertically extending plane around the first attachment means 1035c, via pivoting of the ball joints of the first attachment means 1035c. 25 The above tilt mechanism forms the primary tilt mechanism 1005 for the post driver 1000.

38 The secondary tilt mechanism 1010 is provided through use of independently adjustable and laterally spaced hydraulic legs 1080a, 1080b. As described above in relation to the first embodiment, each of the first and 5 second upright sections 1055, 1070 contain respective left and right legs 1080a, 1080b, which are slidably received within the first and second upright sections 1055, 1070. The first and second legs 1080a, 1080b are independently hydraulically operable and may be adjusted 10 to any required level, for example to compensate for the ground being sloping or to tilt the post driver. In this way, extension of one of the legs 1080a, 1080b and/or retraction of another of the legs 1080a, 1080b may be used to tilt the post driver 1000 laterally 15 through a generally vertical and laterally extending plane. In this way an alternative tilt mechanism may be provided or the primary 1005 and secondary 1010 tilt mechanisms may be used in combination in order to provide a far greater range of tilt that that provided by either 20 mechanism 1005, 1010 alone. Furthermore, the independently operable legs 1080a, 1080b may be used as a machine stabiliser in order to securely support the post driver 1000 on uneven ground. The legs 1080a, 1080b also provide height control for raising or lowering the post 25 driver 1000, for example, to accommodate long posts.

39 An alternative side shift mechanism is disclosed below in relation to this embodiment. However, it will be appreciated that the side shift mechanism of any other embodiment described herein may also be used. In the 5 alternative side shift mechanism, the frame 1015 comprises first 1085 and second frame sections 1090, wherein the attachment means 1035a, 1035b, 1035c are provided on the first frame section 1085 and the mast is supported on the second frame section 1090. A pair of 10 laterally extending slidable sections 1095a, 1095b of the second frame 1090 are laterally slidable into and out of corresponding laterally extending hollow box section members 1100a, 1100b of the first frame section 1085 under the action of hydraulic rams (not shown). In this 15 embodiment, the mast 1020 is located in a position offset to one side of the centre of the post driver 1000 in a lateral direction. Whilst specific examples of possible implementations are described in detail above, it will be appreciated 20 that variations to the above examples within the scope of the claims are contemplated. For example, whilst an opposing piston arrangement 125a, 125b for moving the mast in a lateral (side shift) direction comprising two single action pistons is 25 described, it will be appreciated that one or more double action pistons may be used instead.

40 Furthermore, whilst a dual pulley telescoping mast 110 such as that described in GB 2441071 is detailed above, it will be appreciated that other mast arrangements known in the art may be used. 5 Whilst examples of post drivers are described where the mast is offset to one side and the side shift is provided by two frame sections telescoping into and out of each other and post drivers where the side shift is achieved by providing the mast on a carriage that is 10 movably mounted on a frame section are also described, it will he appreciated that features described in relation to one of the above examples may also be equally applicable to any other example of a post driver described herein. 15 Furthermore, whilst the use and positioning of safety valves has been described in relation to the hydraulic rams used to operate the legs of the post driver, it will be appreciated that equivalent safety valves may be provided in, adjacent or proximate at least 20 one and preferably each of the other hydraulic rams of the post driver, such as the hydraulic tilt ram(s) mast extension ram(s) and/or side shift and/or backshift rams. Therefore, the above detailed description is made by way of example only. 25 In this specification, the terms "comprise", "comprises", "comprising", or similar terms are intended 41 to mean a non-exclusive inclusion, such that a system, method or apparatus that comprises a list of elements does not include those elements solely, but may well include other elements not listed. 5 The reference to any prior art in this specification is not, and should not be taken as, an acknowledgement or any form of suggestion that the prior art forms part of the common general knowledge.

Claims

1. A post driver comprising: a frame, the frame comprising attachment means for 5 mounting the post driver; a mast supported by the frame and adapted to allow a weighted member to travel up and down; at least one tilt mechanism configured to rotate the post driver and/or mast in a lateral direction, wherein 10 at least one of the tilt mechanisms comprises at least two independently operable hydraulically operated legs configured such that at least one leg is extendable and/or at least one other leg is retractable so as to tilt the post driver; and 15 positioning means for enabling the position of the mast to be optimised and adapted for alignment with a post to be driven; wherein the positioning means comprises a side shift configured to move the mast in a lateral direction; 20 the mast is provided on an opposite side of the post driver to the attachment means; and the frame comprises a laterally extending mast support member, and the mast comprises or is mounted on a mast carriage, the mast carriage being slidable or 25 moveable on the support member. 43

2. The post driver according to claim 1, wherein the positioning means also comprises a backshift.

3. The post driver according to claim 1 or claim 2, 5 where the mast is located or locatable at a centre of the post driver in a lateral direction and the side shift is operable to move the mast laterally to both sides of the centre of the post driver in a lateral direction. 10

4. The post driver according to any preceding claim, comprising at least two tilt mechanisms configured to tilt the post driver through a vertical tilt plane.

5. The post driver according to any preceding claim, 15 wherein one or more tilt mechanisms comprise a movable or slidable tilt member, which is mounted on the frame so as to be relatively movable or slidable therewith and the slidable member is fixed relative to at least one attachment means for coupling the post driver to the 20 support apparatus.

6. The post driver according to claim 5, wherein the movable or slidable tilt member is movably or slidably mounted to an upright member of the frame. 25 44

7. The post driver according to claim 5 or claim 6, wherein the post driver comprises at least one further attachment means comprised in or mounted to the frame and spaced laterally from the attachment means of the tilt 5 member.

8. The post driver according to claim 7, wherein the further attachment means comprises a pivoting or pivotable attachment means. 10

9. The post driver according to any preceding claim, wherein the frame comprises a first frame section, which comprises or is provided with the attachment means and the mast is movable or slidable relative to the first 15 frame section.

10. The post driver according to claim 9, the post driver comprising a second frame section that is movable relative to the first frame section, wherein one of the 20 first or second frame sections comprise hollow backshift outer members and the other of the first or second frame sections comprise hollow backshift inner members that are slidably located or locatable within the backshift outer members and backshift drive means are located or 25 locatable within the outer and/or inner backshift members, the backshift drive members being operable to 45 provide relative movement of the first and second frame sections.

11. The post driver of claim 10, wherein wear pads are 5 provided between the inner and outer backshift members.

12. The post driver according to any preceding claim, wherein the side shift comprises a non-telescoping side shift. 10

13. The post driver according to any preceding claim, wherein the side shift comprises at least one side shift driver for moving the mast in a lateral or width wise direction of the post driver. 15

14. The post driver according to claim 13, comprising at least first and second opposing side shift drivers.

15. The post driver of claim 14, wherein the first side 20 shift driver is mounted to a first portion of the second frame section and a second side shift driver is mounted to a second portion of the second frame section, wherein the first portion of the second frame section are on an opposite side of the mast to the second portion. 25 46

16. The post driver according to claim 14 or claim 15, wherein the first and second side shift drivers are arranged in a piggy back configuration, where one end of the first side shift driver is mounted to the mast and/or 5 mast carriage adjacent and above an end of the second side shift driver.

17. The post driver according to any of claims 14 to 16, wherein the side shift driver(s) are single action. 10

18. The post driver according to any of claims 13 to 16, wherein each side shift driver comprises a hydraulic ram having at least two stages and/or a double action ram. 15

19. The post driver according to any preceding claim, wherein the hydraulically operable legs are operable using one or more hydraulic rams driven from a hydraulic pressure feed and/or controller via hydraulic pipes and a safety valve is provided between the hydraulic pressure 20 feed and/or controller and the hydraulic rams, wherein the safety valve is adapted to shut/close in the event that the feed, controller or pipes are depressurised.

20. The post driver according to claim 19, wherein, the 25 safety valve is located further towards the hydraulic ram 47 than towards the hydraulic pressure feed and/or controller.

21. The post driver according to claim 20, wherein the 5 safety valve is incorporated with, located on, adjacent to or proximate to the hydraulic ram.

22. The post driver according to any preceding claim, wherein the attachment means comprises movable or 10 pivotable attachment members.

23. The post driver according to claim 1, wherein the frame comprises a first frame section that comprises or is provided with the attachment means and the mast is 15 movable or slidable relative to the first frame section and a second frame section for supporting the mast and the second frame section is movably or slidably mounted to the first frame section and the side shift comprises the relative lateral movement or sliding of the first and 20 second frame sections.

24. Apparatus comprising a vehicle provided with or having mounted on it a post driver according to any of the preceding claims. 25 48

25. A method of using the post driver according to any of claims 1 to 23 in driving a post into the ground.

26. A post driver substantially as shown in the drawings 5 and/or described herein with respect to the drawings.