Apparatus for removing posts and stumps

Abstract

The invention relates to an apparatus for pulling a post or stump from a ground, the apparatus comprising: a drive system; a frame; and an operating head attached to the frame. The operating head comprises: a jaw assembly comprising a non-hinging digging jaw comprising a distal end for piercing the ground, and a hinged jaw that is moveable toward and away from the digging jaw; and a hammer moveable between a raised, retracted position and a lowered, impact position. The drive system is operatively connected to the frame or operating head and comprises a power source and an actuation system operatively connected to the hammer to power the hammer to reciprocate between the retracted position and the impact position. In the impact position, the hammer impacts on the jaw assembly to hammer the distal end of the digging jaw downwardly into the ground.

Description

[0001] APPARATUS FOR REMOVING POSTS AND STUMPS

[0002] FIELD OF INVENTION

[0003] This invention relates to an apparatus for pulling a post from the ground and is especially suited for pulling subterranean stumps from the ground, such as post stumps or tree stumps.

[0004] BACKGROUND

[0005] There is a common need to remove posts and stumps from the ground in certain situations, especially if the post has rotted or broken. For example, broken or rotten posts in a vineyard or orchard or on a farm, may need to be removed and, in some cases, replaced. Removing a post can be difficult, especially when the post is in heavy ground or the post is a stump that is wholly or mostly located below the surface of the ground (i.e., subterranean).

[0006] United States patent no. 4,706,935 discloses a mechanism for removing posts from the ground. The mechanism comprises a rotatable cam gripper and a vertical gripping plate mounted on a frame and configured to grip the post extending above ground and then raise the post vertically.

[0007] United States patent publication no. 2015 / 047861 discloses a mechanism for removing a tree, shrub, or post from the ground. The mechanism comprises a fixed jaw and a hinged jaw mounted on a frame. The mechanism is positioned to locate the jaws on either side of a post (for example) extending above ground in order to close the hinged jaw and then to raise the jaws, and therefore the post, vertically.

[0008] Although known post pulling mechanisms are useful for removing a post that has a significant portion protruding above ground and that can therefore be gripped between jaws of the mechanism before extraction of the post, such mechanisms are not suitable for removing a post that has broken off below the ground surface or close to the ground surface. Such mechanisms may also be unsuitable for removing posts from heavy ground.

[0009] It would therefore be useful to provide an apparatus for pulling posts that goes at least some way towards overcoming the disadvantages of the prior art, or that at least provides the public with a useful alternative. SUMMARY OF INVENTION

[0010] In a first aspect, the invention provides an apparatus for pulling a post or stump from a ground, the apparatus comprising: a drive system, a frame; and an operating head attached to the frame and comprising a jaw assembly comprising a non-hinging digging jaw comprising a distal end for piercing the ground, and a hinged jaw that is moveable toward and away from the digging jaw; and a hammer moveable between a raised, retracted position and a lowered, impact position; wherein the drive system is operatively connected to the frame or operating head and comprises a power source and an actuation system operatively connected to the hammer to power the hammer to reciprocate between the retracted position and the impact position, wherein in the impact position, the hammer impacts on the jaw assembly to hammer the distal end of the digging jaw downwardly into the ground.

[0011] Preferably, the hammer comprises a substantially vertically orientated reciprocating ram and an anvil located at a lower end of the ram. Preferably, the ram is a hydraulically powered ram.

[0012] In some forms, the hammer reciprocates up and down along a substantially vertical virtual y-axis.

[0013] Preferably, the operating head is vertically moveable up and down relative to the frame.

[0014] In some forms, the operating head is slidably attached to a substantially vertical elongate support shaft that is attached to the frame such that the operating head is vertically moveable up and down relative to the frame. Preferably, the operating head is rotatable about a virtual vertical axis that is substantially parallel with a longitudinal axis of the support shaft.

[0015] In some forms, a first linearly extendable actuating arm attached to the operating head and to a stationary element of the apparatus causes the operating head to slide up and down along the support shaft. Optionally, the stationary element is fixedly attached to the support shaft.

[0016] In some forms, the support shaft is rotatably attached to the frame.

[0017] In some forms, a second linearly extendable actuating arm attached to the frame and the support shaft to pivot the support shaft and operating head relative to the frame.

[0018] In some forms, the operating head is laterally moveable toward and away from the frame.

[0019] In some forms, the frame comprises a connection arm that connects the operating head to the frame, and wherein the apparatus also comprises a directional adjustment system comprising a pair of linearly extending directional actuating arms attached to the frame and to the connection arm, such that extension of one of the directional actuating arms and retraction of the other of the directional actuating arms causes the connection arm, and therefore the operating head, to rotate to one side of the frame.

[0020] In some forms, the frame comprises an extension arm and a linearly extendable actuating arm that is powered by the drive system to laterally extend from and retract toward the frame and that is fixedly or rotatably attached to the frame and to one end of the extension arm.

[0021] Preferably, the digging jaw comprises a contact surface from which a plurality of teeth project outwardly toward the hinged jaw.

[0022] In some forms, the hinged jaw comprises a distal end comprising a prong.

[0023] Preferably, the hinged jaw is hinged from the digging jaw.

[0024] In some forms, the apparatus comprises a fourth linearly extendable actuating arm that is rotatably attached to the hinged jaw and to a bracket of the jaw assembly or the digging jaw, and wherein extension or retraction of the fourth actuating arm opens or closes the hinged jaw.

[0025] In some forms, the jaw assembly comprises an impact element located between the hammer and a proximal end of the digging jaw and wherein the impact element is slidably attached to the operating head to allow the jaw assembly to move toward and away from the operating head.

[0026] Optionally, the impact element is attached to a bracket of the jaw assembly, and is slidably mounted on a pair of opposing guide supports that extend between the jaw assembly bracket member and the operating head body.

[0027] In some forms, each of the pair of opposing guide supports extends through a respective receiving aperture in the impact element and comprises a lower locking element located beneath the impact element to attach the guide supports to the impact element, and wherein the operating head comprises a support element comprising a pair of support element openings that each slidably receive a respective one of the guide supports therein and wherein each of the opposing guide supports comprises an upper locking element located above the support element.

[0028] Preferably, any one or more of the actuating arms is hydraulically, electrically, or mechanically powered by the drive system.

[0029] In preferred forms, the apparatus comprises a support leg to contact the ground during use and support the operating head at a distance above the ground.

[0030] Optionally, the apparatus comprises a receiver to receive instructions from a remote controller, and to transmit the received instructions to a processor of the apparatus, the processor being programmed to operate the actuation system according to the received instructions. In some forms, the apparatus comprises a screen that is attached to the operating head and at least partially shrouds the hammer.

[0031] Preferably, the actuation system is a hydraulic system.

[0032] Preferably, the frame comprises a hitch to attach the apparatus to an agricultural vehicle, such as a tractor.

[0033] Unless the context clearly requires otherwise, throughout the description and the claims, the words "comprise", "comprising", and the like, are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense, that is to say, in the sense of "including, but not limited to".

[0034] Reference to any prior art in this specification is not, and should not be taken as, an acknowledgement or any form of suggestion that that prior art forms part of the common general knowledge in the field of endeavour in any country in the world.

[0035] The invention consists in the foregoing and also envisages constructions of which the following gives examples only.

[0036] BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Preferred forms of the invention will now be described by way of example and with reference to the accompanying drawings, in which:

[0038] Figure 1 is an isometric side view of one form of post-pulling apparatus of the invention;

[0039] Figure 2 is an isometric view of one form of user interface for a remote controller;

[0040] Figure 3a is a plan view of the apparatus of Figure 3a in which the operating head has been rotated fully to the left;

[0041] Figure 3b is a plan view of one form of post-pulling apparatus in which the operating head is in a central position;

[0042] Figure 3c is a plan view of one form of post-pulling apparatus in which the operating head has been rotated fully to the right;

[0043] Figure 3d is an isometric view of one form of post-pulling apparatus with the operating head and connecting arm rotated / slewed to the left;

[0044] Figure 3e is an enlarged view of the rotation / slewing actuation system for the connection arm of the apparatus of Figure 3d at the location K;

[0045] Figure 3f is a side view of the apparatus of Figure 3d;

[0046] Figure 3g is a cross-sectional view of the apparatus of Figure 3f taken along line N-N;

[0047] Figure 4a is a side view of one form of post-pulling apparatus in which the operating head is in an extended position; Figure 4b is a side view of the apparatus of Figure 4a in which the operating head is in a retracted position;

[0048] Figure 5a is an isometric view of one form of post-pulling apparatus in which the operating head has been pivoted to the left of the connection arm;

[0049] Figure 5b is a plan view of the apparatus of Figure 5a when pivoted to the left;

[0050] Figure 5c is an isometric view of the apparatus of Figure 5a in which the operating head has been pivoted to the right of the connection arm;

[0051] Figure 5d is a plan view of the apparatus of Figure 5c;

[0052] Figure 6 is a side view of the apparatus of Figure 1;

[0053] Figure 6a is a cross-sectional view taken along line A-A of Figure 2;

[0054] Figure 6b is an enlarged cross-sectional view of portion A of Figure 6a;

[0055] Figure 7 is an isometric view of one form of operating head body assembly and showing the hammer held vertically by the body;

[0056] Figure 8 is an exploded view of the assembly of Figure 7 and in which the hammer has been removed for clarity;

[0057] Figure 9 is an isometric view of one form of operating head body attached to one form of jaw assembly in which the jaw is in an open position;

[0058] Figure 10 is an isometric view of one form of jaw assembly in which the jaw is in an open position;

[0059] Figure 11 is an isometric view of one form of jaw assembly in which the jaw is in a closed position;

[0060] Figure 12 is another isometric view of the jaw assembly of Figure 11;

[0061] Figure 13 is an isometric front view of a tractor to which one form of post-pulling apparatus of the invention is attached and raised above the ground;

[0062] Figure 14 is an isometric side view of the tractor and post-pulling apparatus of Figure 13;

[0063] Figure 15 is an isometric view of the tractor and post-pulling apparatus of Figure 13 and in which the operating head has been pivoted relative to the connection arm;

[0064] Figure 16 is a schematic view of one form of post-pulling apparatus attached to a tractor and being maneuvered proximate to a post stump to be removed from the ground;

[0065] Figure 17 is a schematic view of the post-pulling apparatus of Figure 16 and in which the operating head has been pivoted relative to the frame to locate the jaw assembly above the post stump; Figure 18 is a schematic side view of one form of post-pulling apparatus of the invention in which the operating head is lowered, and the digging jaw is pushed into the ground adjacent the post stump;

[0066] Figure 19 is a schematic side view of the post-pulling apparatus of Figure 18 in which the digging jaw has been hammered further into the ground and the hinged jaw has closed against the stump so that the stump is held between the hinged jaw and the digging jaw; and

[0067] Figure 20 is a schematic side view of the post-pulling apparatus of Figure 18 in which the operating head is raised to extract the stump from the ground, the stump being gripped between the digging jaw and the hinged jaw in the closed position.

[0068] DETAILED DESCRIPTION OF THE INVENTION

[0069] The invention is further described with reference to the following examples. It will be appreciated that the invention as claimed is not intended to be limited in any way by these examples.

[0070] As exemplified by embodiments shown in Figures 1 to 20, the present invention relates to an apparatus for pulling a post, stump, or the like from the ground. The stump may be the stump of a broken or rotten post, for example, or it may be the stump of a tree or vine or shrub, for example. The apparatus may also be referred to herein as a post-pulling apparatus or a post puller.

[0071] Referring to Figure 1, the apparatus 1000 comprises a frame 1100, which may comprise a hitch 1105 to attach the apparatus to the front or rear of an agricultural vehicle 2000, such as a tractor. Typically, the frame hitch 1105 comprises a three-point linkage attachment system commonly used to attach to a tractor. When attached to the tractor, the apparatus, including the frame, may be lifted and lowered through regular operation of the tractor.

[0072] The apparatus 1000 also comprises an operating head 1200 that comprises a body 1220 attached to a jaw assembly 1250. The operating head 1200 is supported by and is slidable along an elongate support shaft 1230 that is attached to the frame 1100, directly or indirectly, to adjust the vertical position of the operating head 1200 relative to the ground. The operating head 1200 is therefore moveable relative to the frame.

[0073] When in use, the frame 1100 is supported on the ground by a plurality of legs 1110 that extend beneath the frame. In some forms, as shown in Figure 1, distal ends of the legs 1110 comprise enlarged feet 1110a to help prevent the legs 1110 from sinking into soft ground.

[0074] The apparatus 1000 also comprises a drive system connected to a power source and to an actuation system that is operatively connected to a hammer 1240 to power the hammer to reciprocate up and down between a retracted position and an impact position, in which the hammer 1240 impacts on the jaw assembly 1250 from above. The drive system is typically operatively connected to the frame 1100, but may otherwise be operatively connected to the operating head 1200.

[0075] The drive system comprises a motor that may be mounted to the frame 1100 or the motor may be a tractor motor that is operatively connected to the frame 1100 or operating head 1200 to provide power to the apparatus via an electrical connection. The drive system motor powers the actuation system that manipulates at least the vertical position of the operating head 1200 and preferably also manipulates the lateral distance and / or direction of the operating head 1200 relative to the frame 1100.

[0076] The actuation system may operate the jaw assembly 1250, which comprises a digging jaw 1252 and a hinged jaw 1255, to open and close a hinged jaw 1255 in order to grip and release a post or stump between the jaws 1252, 1255.

[0077] In preferred forms, the actuation system is a hydraulic system. The hydraulic actuation system may comprise at least one hydraulic pump, a plurality of hydraulically operated actuating arms, a fluid reservoir connected to a plurality of hydraulic fluid lines and valves that control fluid flow from the pump to one or more actuating arms and vice versa. In some forms, the hydraulic pump and fluid reservoir may be located within a hydraulics housing 1120 mounted on the frame 1100, as shown in Figure 1.

[0078] In other forms, the actuation system may be an electrical system that drives one or more electrically powered actuating arms that are electrically connected to the motor, or the actuating system may be powered in any other suitable manner. A hydraulic system, however, has been found to be a robust system for agricultural use.

[0079] Operation of the actuation system is powered by the drive system and controlled by a controller. Preferably, the controller is a programmable controller 1180 comprising a data processor and a non-tangible storage medium for storing operating instructions. In some forms, the apparatus 1000 comprises a receiver 1130 to receive instructions (such as via radio signals) from a remote controller 1180 and to transmit those instructions / signals to the processor, which is programmed to operate the actuation system according to the control instructions / signals received.

[0080] In some forms, the receiver 1130 may be located on the frame 1100. In other forms, the receiver 1130 may be located on the operating head 1200.

[0081] In some forms, the programmable controller 1180 is a remote controller comprising a user interface, as shown in Figure 2, such as a handheld controller or a controller located within the cab of the agricultural vehicle, such as a tractor. Operating the apparatus 1000 by remote control allows the operator to be at a safe distance from the apparatus during use.

[0082] In yet other forms, the controller may be a manually operated controller. For example, the apparatus may comprise a hydraulic valve bank (that may be mounted on or operatively connected to the frame 1100) comprising a plurality of mechanical levers configured to be manipulated by an operator to control the actuation system of the apparatus.

[0083] The position of the operating head 1200 relative to the frame may be varied. For example, the apparatus comprises a vertical adjustment system in which the operating head 1200 is configured to move vertically up and down relative to the frame 1100.

[0084] In some forms, the apparatus comprises a directional adjustment system and / or an extension system in which the operating head 1200 may also be moved laterally toward the frame 1100 and away from the frame in a substantially horizontal plane.

[0085] In some forms, the apparatus comprises a fine adjustment pivoting system in which the operating head 1200 may be pivotable from left to right relative to the frame 1100.

[0086] Therefore, the operating head may be moveable vertically and pivotable from left to right relative to the frame 1100, or the operating head 1200 may be moveable vertically, laterally, and pivotable from left to right relative to the frame 1100.

[0087] In some forms, as shown in Figures 3a to 3g, to allow for lateral movement of the operating head 1200 relative to the frame 1100, the apparatus 1000 comprises a directional adjustment system, which may also be referred to as a slew system. Preferably, the directional adjustment system provides the operating head 1200 with about 180° of movement. In some forms, the directional adjustment system may comprise a rotatable connection arm 1140 that connects the frame 1100 to the operating head 1200, as shown in Figures 1 and 3a to 3c. The connection arm 1140 is rotatably mounted on the frame 1100 at a connection joint 1142. In some forms, the connection arm 1140 is fixedly attached to a slew bracket 1150 that comprises a sheath 1151 within which a pivot pin 1144 is partially or wholly located, as shown in Figures 3e and 3g. The pin 1144 comprises a longitudinal axis and the slew bracket 1150 is configured to rotate freely about the longitudinal axis of the pin 1144 by rotating the bracket 1150 and sheath 1151 about the pin. The pin 1144 is secured to the frame 1100 at first end second ends of the pin 1144. In some forms, a first end of the pin 1144 is secured to a bearing element 1145 of the frame 1100, and a second end of the pin 1144 may be secured to an attachment element 1149 of the frame 1100 by a fastener 1144a, such as a nut or bolt, for example.

[0088] In some forms, the directional actuators comprise a pair of linearly extending actuating arms 1143a, 1143b, as shown in Figure 3e, which may be electrically, hydraulically, or mechanically powered by the drive system. In preferred forms, the directional actuating arms 1143a, 1143b are hydraulically powered rams.

[0089] In some forms, the bearing element 1145 is fixedly attached to the frame 1100.

[0090] In some forms, the actuating arms 1143a, 1143b are also fixedly attached to the frame 1100, such as via an attachment bracket 1146. In addition, the actuating arms 1143a, 1143b may be rotatably attached to the slew bracket 1150, such as to an upper plate 1152 of the slew bracket 1150, for example. The upper plate 1152 may be located between the bearing element 1145 and the sheath 1151. In some forms, each arm 1143a, 1143b is rotatably attached to a respective pivot element 1147a, 1147b, each of which is fixedly attached to the slew bracket 1150 (such as to the upper plate of the slew bracket) at a substantially equal distance from a central point of the connection joint 1142.

[0091] The central point of the connection joint 1142 preferably forms the longitudinal axis of the pivot pin 1144. In some forms, each pivot element 1147a, 1147b comprises a substantially cylindrical bearing that projects from the slew bracket 1150 and is connected to the other pivot element by a support member 1148, configured to provide structural rigidity to the pivot elements 1147a, 1147b.

[0092] To rotate the connection arm 1140 in a first direction (and therefore to move the operating head in the same direction) as shown in Figure 3a, one of the actuating arms 1143a is extended and the other arm 1143b is retracted. As the arm 1143a extends, its distal end pushes against the respective pivot element 1147a to which the arm 1143a is rotatably attached, whilst retraction of the other arm 1143b pulls the respective pivot element 1147b toward the arm 1143b, causing the slew bracket 1150 to rotate about the pin 1144 in the first direction. Because the connection arm 1140 is attached to the slew bracket 1150, the connection arm 1140 is also caused to rotate in the first direction. Full rotation in the first direction may cause the connection arm 1140 to project to the left, as shown in Figure 3a.

[0093] To rotate the connection arm 1140 in the second direction, opposite to the first direction, the reverse is applied. For example, the actuating arm 1143a is retracted to pull the respective pivot element 1147a toward the arm 1143a, and the actuating arm 1143b is extended to push the respective pivot element 1147b away from the arm 1143b, causing the slew bracket 1150 and therefore the connection arm 1140 to rotate in the second direction. Full rotation in the second direction may cause the connection arm 1140 to project to the right, as shown in Figure 3c.

[0094] To centre the connection arm 1140, both the first and second actuation arms 1143a, 1143b may be extended to substantially the same length, as shown in Figure 3b. Therefore, the directional actuation arms 1143a, 1143b are configured so that: extension of a first one of the arms 1143a, 1143b and retraction of a second one of the arms 1143a, 1143b causes the connection arm 1140 to rotate to the left to adopt a left facing position, as shown in Figure 3a; retraction of the first one of the arms 1143a, 1143b and extension of the second one of the arms 1143a, 1143b causes the connection arm 1140 to rotate to the right to adopt a right facing position, as shown in Figure 3c; and either extension or retraction of both arms 1143a, 1143b to reach substantially the same length causes the connection arm 1140 to project substantially straight ahead to adopt a central position, as shown in Figure 3b. In a preferred form, extension of both arms 1143a, 1143b causes the connection arm 1140 to project substantially straight ahead in the central position, such as in an opposing direction to the hitch 1105.

[0095] In some forms, the apparatus may comprise an extension system to move the operating head 1200 laterally toward and away from the frame 1100. To allow for lateral extension of the operating head 1200 relative to the frame 1100, the extension system of the apparatus 1000 may comprise a linear extension arm 1140a that is provided on the frame 1100 and is attached to the operating head 1200. In some forms, the connection arm 1140 forms the linear extension arm 1140a such that the connection arm 1140 is configured to rotate left and right, extend away from the frame 1100, and retract toward the frame 1100.

[0096] The linear extension arm 1140a is extendable in a first direction to an extended position, as shown in Figure 4a, and is retractable in a second direction, opposite to the first direction, to a retracted position, as show in Figure 4b. In some forms, a first end of the extension arm 1140a attaches to the operating head 1200 and a second end of the extension arm 1140a is directed away from the operating head. In some forms, as shown in Figure 1, the frame comprises a sheath 1141 that surrounds at least a portion of the extension arm 1140a such that the extension arm 1140a is slidable within the sheath 1141.

[0097] Lateral movement of the extension arm 1140a is governed by the actuation system, which is controlled by the controller 1180, and powered by the drive system. In some forms, movement of the extension arm 1140a is actuated by a lateral movement actuator.

[0098] In some forms, the lateral movement actuator comprises a linearly extendable actuating arm 1101, such as a hydraulic ram, that is attached to the frame 1100 at one end of the arm 1101 and to the operating head 1200 at the other end of the arm 1101. In some forms, one end of the actuating arm 1101 is attached to a sheath 1141 and the other end of the arm 1101 is attached to the operating head 1200. The actuating arm 1101 is powered by the actuation system, powered by the drive system, to move between the extended and retracted positions. In this arrangement, extension of the first actuating arm 1101 may push the operating head 1200 away from the frame 1100, causing the extension arm 1140a to extend from the sheath 1141 so that the operating head 1200 is distanced from the frame in the extended position. Conversely, retracting the first actuating arm 1101 may pull the operating head 1200 toward the frame 1100, causing the extension arm 1140a to retract into the sheath 1141 so that the operating head 1200 is moved closer to the frame 1100 in the retracted position. The actuating arm 1101 may be fixedly attached to the support shaft 1230 of the operating head 1200, or the arm 1101 may be rotatably attached to the support shaft 1230 to allow the support shaft 1230 to pivot relative to the extension arm 1140a and the frame 1100.

[0099] In other forms, the motor drives a mechanical drive system that causes the extension arm 1140a to extend and retract. The mechanical drive system may be any suitable system to cause linear movement of the extension arm 1140a as would be appreciated by a person skilled in the art, such as a chain drive, a geared system, or a ratchet system, for example.

[0100] The operating head 1200 is suspended above the ground and is supported in a suspended position (in use) by a support leg 1210 comprising a shaft 1211 and a foot 1210a at its distal end. The foot 1210a is configured to rest on the surface of the ground 4000 during use of the apparatus 1000 and is preferably enlarged to help prevent the support leg 1210 from sinking into soft ground.

[0101] In some forms, as shown in Figure 1, the operating head 1200 is slidably mounted on the support leg shaft 1211 so that the support leg 1210 can be raised and lowered relative to the operating head 1200 and the frame 1100 to accommodate an uneven ground surface. Preferably, the support leg 1210 is attached to both the operating head 1200 and the frame 1100. In some forms, the operating head 1200 comprises an attachment bracket 1215 that attaches the operating head 1200 to the frame 1100, such as to the first end of the extension arm 1140a. In some forms, the attachment bracket 1215 is also slidably attached to the support leg 1210 to allow the support leg to slide vertically relative to the frame 1100 and the operating head 1200. In some forms, the attachment bracket 1215 is fixedly attached to the frame 1100 (such as via the connection arm 1140 or extension arm 1140a) and in other forms, the attachment bracket 1215 is pivotably attached to the frame 1100 (such as via the connection arm 1140 or extension arm 1140a).

[0102] The support leg 1210 may be attached to the frame 1100 (such as via the extension arm 1140a) and the operating head 1200 by any suitable attachment system. Where the operating head 1200 is laterally moveable relative to the frame, the support leg 1210 attachment system should allow for that range of movement. Similarly, where the operating head 1200 is rotatably moveable relative to the frame then the support leg attachment system should allow for that range of movement. Preferably, the support leg attachment system also allows the support leg shaft 1211 to slide relative to the operating head 1200. In some forms, the attachment system comprises an opening in the connection arm 1140 or the extension arm 1140a through which the support leg is slidably received and the extension arm is fixedly or pivotably attached to the support shaft 1230. In other forms, the extension arm 1140a passes through an opening, such as a vertical slot, in the shaft 1211 of the support leg 1210. In yet other forms, the support leg 1210 may be welded to, or integrally formed with, the extension arm 1140a, but in such an arrangement, the vertical position of the support leg relative to the frame is unable to be adjusted to accommodate uneven ground.

[0103] In other forms, the operating head 1200 may be directly attached to the first end of the connection arm 1140 or to the extension arm 1140a (where the connection arm and extension arm are not coincident), such as by mounting the support shaft 1230 to the arm 1140 or 1140a, in which case the operating head 1200 may not be rotatable relative to the frame 1100. In yet other forms, the operating head 1200 may be fixedly or rotatably attached directly to the frame 1100, such as by mounting the support shaft 1230 to the frame.

[0104] The support leg 1210 supports the operating head 1200 in position above the ground, and also acts as a fulcrum against which the operating head 1200 can lever a post or stump from the ground 4000.

[0105] Referring to Figure 1, the elongate support shaft 1230 extends in a substantially vertical direction and the operating head body 1220 is slidably mounted on the support shaft 1230, to slide up and down relative to the support shaft 1230 and the frame 1100.

[0106] In some forms, the vertical adjustment system of the apparatus 1000 comprises a vertical positioning actuator 1205 configured to cause the body 1220 of the operating head 1200 to slide up and down along the length of the support shaft 1230 upon receipt of a vertical position adjustment command from the controller 1180. In some forms, as shown in Figure 5, the vertical positioning actuator 1205is a linearly extendable actuating arm comprising a first end that is attached to the operating head body 1220 and a second end that may be attached to a stationary element relative to the operating head body 1220 (i.e., an element that is not raised or lowered relative to the operating head body). For example, the stationary element may be the operating head attachment bracket 1215, as shown best in Figure 1, or the support shaft 1230, the support leg 1210, the extension arm 1140a, or the frame 1100. The linearly extendable actuating arm 1205 may be electrically, hydraulically, or mechanically powered. Preferably, the arm 1205 is a hydraulically powered ram, driven by the drive system and controlled by the controller 1180. In some forms, by extending the actuating arm 1205, the body 1220 is pushed away from the ground 4000 to slide the operating head 1200 upwardly along the support shaft 1230 in order to raise the operating head 1200. By retracting the actuating arm 1205, the body 1220 is pulled toward the ground 4000 to slide the operating head 1200 downwardly along the support shaft 1230 in order to lower the operating head 1200. In this manner, the vertical position of the operating head 1200 may be adjusted relative to the frame 1100.

[0107] In some forms, the operating head 1200 is rotatable relative to the frame 1100 via a fine adjustment pivoting system. For example, as shown in Figures 5a to 5d, the support shaft 1230, and therefore the operating head 1200, may be rotatably attached to the frame 1100 via an attachment bracket that is configured to allow the support shaft 1230 to rotate about its longitudinal axis. Rotation of the support shaft 1230 and therefore of the operating head 1200, may be caused by a rotational actuator that is governed by the actuation system, powered by the drive system, and optionally controlled by the control system. In such an arrangement, the operating head 1200 is rotatable about a vertical axis.

[0108] For example, an attachment bracket 1215 may be fixedly attached to one end of the connection arm 1140 or the extension arm 1140a and may comprise a first portion 1215a and a second portion 1215b that is rotatably attached to the first portion 1215a about a substantially vertical pivot shaft. The first portion 1215a comprises a vertical opening in which the support leg 1210 is slidably received and may be secured in position by a locking system such as a clamping arrangement, a pin and hole arrangement, or any other suitable locking system to hold the support leg in position relative to the extension arm 1140a. The second portion 1215b provides a mounting structure to which the support shaft 1230 is fixedly attached. Preferably, a lower end of the support shaft 1230 is attached to the second portion 1215b of the attachment bracket 1215. The attachment bracket 1215 forms a stationary element relative to the vertically moveable operating head 1200 and allows the operating head 1200 to pivot / rotate relative to the frame 1100 by rotating the second portion 1215b of the attachment bracket and therefore of the shaft 1230. In some forms, as shown best in Figures 5a to 5d, the apparatus 1000 may comprise a rotational actuator 1206 configured to cause the operating head 1200 to rotate to the left or to the right upon receipt of a rotational position adjustment command from the controller 1180. In some forms, as shown in Figure 5a, the rotational actuator 1206 comprises a linearly extendable actuating arm 1206 that is attached to the frame 1100 and the support shaft 1230 or to the second portion 1215b of the attachment bracket 1215 in order to rotate the support shaft 1230 and operating head 1200 relative to the frame 1100. The actuating arm 1206 may be electrically, hydraulically, or mechanically powered. Preferably, the actuating arm 1206 is a hydraulic ram. In some forms, an elongate element 1216 extends from one side of the extension arm 1140a, the first portion 1215a of the attachment bracket 1215, or from the support leg 1210, and comprises a pivot shaft 1217 that extends in a generally vertical direction and to which one end of the actuating arm 1206 is rotatably attached. The actuating arm 1206 may also be rotatably attached, at its opposing end, to the support shaft 1230 or to the attachment bracket 1215 (such as to the second portion of a two- part attachment bracket, as described above). The operating head 1200 may therefore be rotatable about the virtual vertical axis of rotation of the second portion 1215b of the attachment bracket 1215 that is substantially parallel with a longitudinal axis of the support shaft 1230.

[0109] The operating head 1200 comprises a hammer 1240 and a jaw assembly 1250 located beneath the hammer 1240, as shown in Figures 6a to 9. The hammer 1240 is typically mounted on the operating head body 1220. In some forms, as shown in Figure 8, the body 1220 comprises a collar 1221 comprising a first opening 1222 therein, and a support element 1223 comprising a second opening 1226 therein. The hammer 1240 is at least partially held within the first opening 1222 and the second opening 1226.

[0110] In some forms, the hammer comprises a reciprocating ram that is substantially vertically orientated and that comprises an anvil 1242 at a lower end of the ram. In some forms, the hammer 1240 comprises a substantially elongate housing 1241, such as a cylindrical housing and the ram is located within the housing. In such forms, an opening may be provided at the lower end of the housing 1241 through which the anvil 1242 projects. An upper end of the hammer housing 1241 may be held within the collar opening 1222 and a lower end of the hammer housing 1241 may be held within the second opening 1226 to hold the hammer 1240 to the body 1220. Thus, the body 1220 supports the hammer 1240 substantially vertically such that the hammer 1240 is substantially longitudinally aligned with the support shaft 1230 and the anvil 1242 of the hammer is located directly above the jaw assembly 1250. Of course, this is just one manner of holding the hammer to the body 1220, other features may be used instead to attach the hammer to the body and hold the hammer in a substantially vertical position, as would be appreciated by a person skilled in the art.

[0111] The hammer 1240 is governed by the actuation system, powered by the drive system, and optionally controlled by the control system. The hammer 1240 may be electrically powered, but is preferably hydraulically powered such that the reciprocating ram is a hydraulic ram connected to the fluid reservoir by at least one fluid conduit.

[0112] The hammer 1240 reciprocates up and down along a substantially vertical virtual y-axis between a retracted, raised position and a lowered, impact position.

[0113] In some forms, as shown best in Figures 6a and 6b, the hammer housing 1241 comprises a laterally projecting flange 1240a that rests on, or is attached to, the support element 1223. The support element 1223 is supported by the operating head body 1220 and may extend between two opposing substantially vertical sides of the body to provide a substantially horizontal support for the hammer 1240. Referring to Figures 1, and 8 to 12, the jaw assembly 1250 comprises a jaw assembly bracket, and a set of jaws comprising a digging jaw 1252 comprising a distal end 1252b for piercing the ground, and a hinged jaw 1255 that is moveable toward and away from the digging jaw 1252. In some forms, the jaw assembly bracket comprises a bracket member 1251 and an impact element 1243 that is attached to the bracket member 1251, as shown in Figure 4. In other forms, the jaw assembly bracket may comprise a single part in which the impact element 1243 is integrally formed with the bracket member 1251.

[0114] The jaw assembly 1250 may be vertically moveable relative to the operating head body 1220. In some forms, the jaw assembly may be attached to the operating head body 1220 via a floating hitch or the like. For example, the impact element 1243 is located between the hammer 1240 and a proximal end of the digging jaw 1252 and may be slidably attached to the operating head 1200 to allow the jaw assembly 1250 to move toward and away from the operating head.

[0115] In some forms, as shown in Figures 8 and 9, the jaw assembly 1250 is attached to the operating head body 1220 via a floating hitch that comprises at least two guide supports 1245 that are attached to and extend between the jaw assembly bracket member 1251 and the operating head body 1220. The impact element 1243 of the jaw assembly may be slidably mounted on the guide supports 1245.

[0116] In some forms, each of the opposing guide supports 1245 extends through a respective receiving aperture 1244 in the impact element 1243. Preferably, two guide supports 1245 are provided at each side of the impact element 1243. Each guide support 1245 comprises a lower locking element 1246 located beneath the impact element to preclude retraction of the guide supports 1245 from the impact element 1243 and to thereby attach the guide supports 1245 to the impact element 1243. In effect, the lower locking element 1243 acts as a stop to limit the downward movement of the impact element 1243 relative to the guide supports 1245. In some forms, the lower locking element 1246 may be a nut attached to a threaded lower end of a respective guide support, or the lower locking element 1246 may be a flange that projects from a lower end of a respective guide support, or the lower locking element 1246 may be a pin that passes through the lower end of a respective guide support, or the lower locking element 1246 may be any other feature that precludes detachment of the respective guide support 1245 from the impact element 1243. In the embodiment shown in Figures 8 and 9, the lower locking element 1246 comprises a nut that attaches to a threaded portion of the respective guide support. A washer 1247 may be provided between the nut and a lower surface of the impact element 1243.

[0117] In some forms, the support element 1223 of the operating head body 1220 comprises at least two support element openings 1244 that each receive a respective one of the guide supports 1245 therein. In some forms, the guide supports 1245 are slidably received within the openings

[0118] 1244 of the support element 1223. In some forms, as shown in Figures 8 and 9, the support element openings 1244 are provided within cylindrical bushings 1223a to help support the generally vertically alignment of each guide member 1245. In other forms, the support element 1223 may be substantially thick to provide substantially cylindrical openings to help support the alignment of each guide member. Preferably, two guide supports 1245 are provided and are located at each side of the support element 1223.

[0119] In some forms, a seal is provided between each of the guide supports 1245 and the opening 1244, such as between the guide supports 1245 and the bushing 1223a. The seal is configured to help prevent dust and debris from entering the support element openings 1244 and inhibiting sliding movement of the impact element 1243 along the guide supports 1245. Each seal may also reduce slop between the respective guide element and opening 1244. In some forms, the seal comprises an internal bush 1224 that surrounds a portion of the respective guide support 1245, the guide support 1245 being located within a tubular opening in the bush 1224. The bush 1224 is located within the support element opening 1244, such as within cylindrical bushings 1223a that define the opening 1244. In some forms, as shown in Figure 8, a circumferential channel 1224a may surround a portion of the bush 1224 and may be configured to receive a sealing member 1225 therein, such as a split ring sealing member.

[0120] In some forms, each guide support 1245 comprises an upper locking element 1245 located above the support element 1223 to preclude retraction of the guide supports from the support element 1223 and to thereby attach the guide supports 1245 to the support element 1223. In some forms, at least one seal (comprising an internal bush 1224 and a sealing member 1225) is located above and below the upper locking element of the guide supports 1245, the upper locking element

[0121] 1245 therefore being located between the sealing members 1225, as shown in Figure 8. In some forms, the upper locking element 1248 is retractable and may comprise a retractable pin to allow for easy disassembly of the guide supports 1245 from the operating head body 1220 for maintenance purposes. The impact element 1243, and therefore the jaw assembly 1250, is slidable along the guide supports 1245 between the upper and lower locking elements 1246, 1248 and preferably between the support element 1223 and the lower locking element 1248.

[0122] One form of jaw assembly 1250 is shown in Figures 10 to 12. The jaw assembly 1250 comprises a jaw assembly bracket member 1251, a digging jaw 1252 and a hinged jaw 1255.

[0123] In some forms, the impact element 1243 is integrally formed with the jaw assembly bracket member 1251. In other forms, the impact element 1243 is attached to the jaw assembly bracket member 1251 at one or more attachment joints. In a preferred form, the impact element 1243 is attached to the jaw assembly bracket member 1251 at two attachment joints 1251a, 1251b, as shown in Figures 9 and 10. The attachment joint(s) 1251a, 1251b may be of any suitable form for attaching the impact element 1243 to the jaw assembly bracket member 1251. In some forms, the attachment joints 1251a, 1251b comprise removable pins that pass through connection apertures formed in the impact element 1243 and the jaw assembly bracket member 1251, the pins being removable to allow for removal of the jaw assembly 1250 from the impact element 1243 for replacement or repair.

[0124] The digging jaw 1252 may be attached to or integrally formed with the jaw assembly bracket. The position of the digging jaw is fixed in relation to the jaw assembly bracket so that, although the digging jaw can move up and down together with the up and down movement of the operating head, the digging jaw 1252 is unable to move independently. That is to say, the digging jaw is non-hinging. The digging jaw 1252 comprises a distal end 1252b that is directed downwardly below the operating head 1200, and a proximal end 1252a that is fixedly or removably attached to the operating head 1200, directly or indirectly, such as via an attachment bracket or other suitable form of attachment. For example, in some forms, the digging jaw 1252 comprises a proximal end 1252a attached to a jaw assembly bracket. In preferred forms, the digging jaw 1252 is removably attachable to the operating head 1200. Preferably, the digging jaw 1252 extends substantially vertically below the operating head 1200. The digging jaw 1252 may comprise a digging tip at its distal end / lower end 1252b. In some forms, the digging jaw comprises a digging tip at its lower / distal end that projects beneath the operating head 1200 and towards the ground. In some forms, the distal end 1252b of the digging jaw is tapered to form a digging tip for piercing the ground. In some forms, the digging jaw 1252 comprises a contact surface from which a plurality of teeth 1253 project outwardly toward the hinged jaw 1255. The teeth 1253 may be configured to grip against a post or stump 3000 during removal of the post or stump. Typically, the contact surface faces toward the opposing hinged jaw 1255 so that the teeth 1253 project toward the hinged jaw and into an operating space located between the digging jaw and the hinged jaw. The operating space is made available to receive a portion of a post or stump therein.

[0125] The hinged jaw 1255 is rotatable about a pivot point so that the hinged jaw 1255 is able to hinge relative to the digging jaw 1252. In some forms, the hinged jaw 1255 is rotatably connected to the digging jaw 1252 at a first pivot joint 1256, which may be located at or near a proximal end of the hinged jaw 1255. In other forms, the hinged jaw 1255 may hinge from the operating head, such as from an attachment bracket that attaches the jaw assembly to the operating head, or from another suitable for of attachment, or from the operating head 1200. The hinged jaw 1255 also comprises a distal end that moves toward and away from the digging jaw 1252 as the hinged jaw is hinged between a closed position and an open position respectively. In some forms, the distal end of the hinged jaw 125 comprises a prong 1255a for piercing a post or stump located within the operating space between the hinged jaw and digging jaw during use, as shown in Figure 6.

[0126] The hinged jaw 1255 is configured to move between an open position as shown in Figure 10, and a closed position, as shown in Figures 11 and 12. In the open position, the jaw 1255 is rotated away from the digging jaw 1252 to increase the distance between the jaws 1252, 1255 and expand the width of the operating space to better receive a post or stump therein. In the closed position, the jaw 1255 is rotated toward the digging jaw 1252 to decrease the distance between the jaws 1252, 1255 and therefore to reduce the width of the operating space to better clasp or clamp a post or stump therein. The prong 1255a, where present, projects generally in the direction of the digging jaw 1252 when the hinged jaw 1255 is in the closed position to pierce a post or stump between the digging jaw and hinged jaw to help grip the post or stump prior to, and during, extraction of the post or stump by the apparatus of the invention.

[0127] The jaw assembly 1250 also comprises an electrically, mechanically, or hydraulically powered hinged jaw actuator to open and close the hinged jaw 1255 relative to the jaw assembly bracket and the digging jaw 1252, whilst the position of the digging jaw 1252 remains fixed relative to the jaw assembly bracket. In some forms, the hinged jaw actuator may be a linearly extending actuating arm 1257. Preferably, the hinged jaw actuating arm is a hydraulically powered ram. The actuating arm 1257 may be rotatably connected to both the jaw assembly bracket member 1251 and the hinged jaw 1255, or to the digging jaw 1252 and the hinged jaw 1255. In some forms, a first end of the actuating arm 1257 is rotatably attached to the jaw assembly bracket member 1251 at a second pivot joint 1258 and a second end of the actuating arm 1257 is rotatably attached to the hinged jaw 1255 at a third pivot joint 1259. Preferably, the hinged jaw 1255 is substantially curved to form a crescent-like shape (having a proximal end at one end of the crescent and a distal end at the other end of the crescent), and the second end of the actuating arm 1257 is located part -way, and preferably approximately halfway, between the proximal end and the distal end of the hinged jaw 1255. The hinged jaw actuating arm 1257 is configured so that extension and retraction of the actuating arm 1257 causes the hinged jaw 1255 to move between the closed position and the open position. Preferably, extension of the actuating arm 1257 closes the jaw 1255 and retraction of the actuating arm 1257 opens the jaw 1255, but the system may be set up to operate in the alternative.

[0128] Any one or more of the actuating arms 1101, 1205, 1206, 1257 may be hydraulically, electrically, or mechanically powered by the drive system and optionally controlled by the controller. In some forms, the apparatus also comprises a screen 1260 that is attached to the operating head 1200 and at least partially shrouds the hammer 1240, as shown in Figures 1, 5a and 5c for example. The screen is configured to reduce the likelihood that foliage from nearby plantings could interfere with the operation of the apparatus, or otherwise get caught up in the apparatus.

[0129] The operating head 1200 is configured to drive the digging jaw 1252 of the jaw assembly 1250 substantially vertically into the ground 4000, preferably close to a post or stump 3000 to be removed, by lowering the operating head 1200 to push the digging jaw 1252 downward. The distal end of the digging jaw contacts or pieces the ground surface once it is lowered to the ground by the operating head 1200. The hammer 1240 is then activated to hammer the digging jaw 1252 further into the ground 4000, where necessary. The hinged jaw 1255 is then moved toward the digging jaw 1252 to grip the post or stump 3000 within the operating space between the digging jaw and the hinged jaw. As the hinged jaw 1255 moves toward the digging jaw, the hinged jaw is caused to cut or pull its way through the ground to reach the post or stump 3000, until the hinged jaw 1255 reaches the closed position in which the hinged jaw 1255 presses firmly against the post or stump and the prong, where present, pierces the post or stump 3000. Preferably, the hinged jaw 1255 has a substantially thin width to enable ease of movement through the ground as the jaw 1255 moves toward the post or stump. In the closed position, the post or stump is held firmly between the hinged jaw 1255 and the digging jaw 1252. The operating head 1200 is then raised to pull the post or stump 3000 from the ground.

[0130] One example of use of the apparatus 1000 of the invention will now be described in relation to extraction of a post stump 3000.

[0131] To move the apparatus to the site of the post or stump to be removed, the apparatus 1000 is hitched to an agricultural vehicle, such as a tractor, via the hitch 1105. The apparatus is raised off the ground using the normal controls of the tractor and the apparatus 1000 is driven to site, as shown in Figures 13 to 15. As can be seen, the apparatus shown in Figures 13 to 15 comprises a directional system and the operating head has been rotated to one side.

[0132] At the site, the apparatus 1000 is lowered to the ground surface 4000 until the frame 1100 sits on its legs 1110, as shown in Figures 16 and 17. The operating head 1200 remains suspended above the ground.

[0133] Where the apparatus comprises a directional adjustment system, the operating head 1200 may be rotated to the desired directional position before the apparatus is lowered to the ground. For example, to rotate the operating head to the left side of the frame (which is the right side of the tractor in Figure 14), the currently extended directional actuating arm is retracted and the currently retracted directional actuating arm is extended to cause the connection arm 1140 to rotate to the desired position.

[0134] Where the apparatus comprises an extension system, the operating head 1200 may additionally or alternatively be extended from, or retracted toward, the frame 1100 before the apparatus is lowered to the ground. For example, by extending the actuating arm 1101, the extension arm 1140a is caused to extend from the sheath 1141, thereby pushing the operating head 1200 away from the frame. Where the apparatus also comprises a directional adjustment system, the operating head 1200 may be caused to extend in the direction as set by the directional adjustment system. Where the apparatus does not include a directional adjustment system, the operating head 1200 extends in the longitudinal direction of the extension arm 1140a and the extension arm is located on the frame in a fixed orientation.

[0135] Preferably, the apparatus 1000 comprises a directional adjustment system and an extension system so that the operating head 1200 can be easily manoeuvred as close as possible to the post or stump to be removed.

[0136] Once the apparatus 1000 is lowered in position, the operating head is supported above the ground by the support leg 1210. Where the apparatus comprises a fine adjustment pivoting system, the operating head 1200 may be pivoted / rotated relative to the frame 1100 to locate the digging jaw 1252 proximate to the post or stump to be removed by extending or retracting the rotational actuator 1206 to rotate the support shaft 1230 and operating head 1200 to the desired position. Figure 16 shows one form of apparatus in which the operating head 1200 has been rotated to the right of the apparatus via a directional adjustment system and extended from the frame 1100 via an extension system. Figure 17 shows the same apparatus but in which a fine adjustment pivoting system has been employed to pivot the operating head 1200 relative to the connection arm 1140 so that the operating head forms an angle of between 90° and 180° with a longitudinal axis of the connection arm 1140.

[0137] The operating head 1200 is positioned so that the digging jaw 1252 is above the post stump and to one side of the stump 3000. Movement of the operating head 1200 to the desired orientation and position may be controlled by the controller 1180 via inputs from an operator.

[0138] The screen 1260 separates the moveable components of the operating head from vine wires or fence wires or foliage adjacent to the stump 3000 to be removed.

[0139] Once the operating head 1200 is in the desired position, the operating head may be lowered by sliding the operating head down the support shaft 1230 by extending the vertical adjustment actuating arm 1205. The operating head 1200 is lowered to push the digging jaw 1252 into the ground beside the stump 3000, as shown in Figure 18. As the digging jaw is pushed downwardly, the resistance force of the ground pushes upwardly.

[0140] Once the digging jaw 1252 is unable to be pushed further into the ground, the resistance force pushes the jaw assembly and therefore the impact element 1243 upwardly so that the impact element slides upwardly along the guide members 1245. The controller 1180 causes the actuation system to actuate the hammer 1240 to reciprocate between the retracted position and the impact position, preferably regularly and rapidly. The hammer 1240 and jaw assembly 1250 are configured so that when the hammer is in the impact position, the anvil of the hammer 1240 impacts on the impact element 1243 of the jaw assembly 1250 to hammer the distal end of the digging jaw 1252 downwardly into the ground. As the hammer hits the impact element 1243, the impact element 1243 is caused to slide downwardly along the guide members 1245 allowing the digging jaw to be pushed further into the ground. Consistent downward pressure on the operating head 1200 to cause the push or pull the operating head downwardly along the support shaft 1230 and repeated hammering by the hammer 1240 will drive the digging jaw 1252 into the ground beside the post stump 3000. Once the digging jaw 1252 is sufficiently embedded into the ground to clamp the post stump 3000 between the digging jaw 1252 and the hinged jaw 1255, the hinged jaw is closed, such as by instructing the controller 1180 to cause the actuation system to extend the hinged jaw actuating arm 1257. The post stump 3000 is now located between the digging jaw 1252 and the hinged jaw 1255. Teeth 1253 of the digging jaw 1252 and the prong 1255a of the hinged jaw 1255 may embed into sides of the stump 3000 to grip the stump firmly, as shown in Figure 19.

[0141] The operating head 1200 is then raised upwards, by reversing movement of the vertical adjustment actuating arm 1205. For example, the controller 1180 may cause the actuation system to retract the arm 1205 in order to pull or push the operating head 1200 upwardly along the support shaft 1230. As the operating head 1200 is moved upwardly, and therefore the jaw assembly 1250 is pulled upwardly, the stump 3000 is extracted from the ground, as shown in Figure 20.

[0142] The controller 1180 may activate the actuation system according to user inputs from an operator and / or according to pre-programmed instructions carried out by the processor of the controller.

[0143] The invention may also be said broadly to consist in the parts, elements and features referred to or indicated in the specification of the application, individually or collectively, in any or all combinations of two or more of said parts, elements or features.

[0144] Where, in the foregoing description reference has been made to integers or components having known equivalents thereof, those integers are herein incorporated as if individually set forth. It should be noted that various changes and modifications to the presently preferred embodiments described herein will be apparent to those skilled in the art. Such changes and modifications may be made without departing from the scope of the invention and without diminishing its attendant advantages. It is therefore intended that such changes and modifications be included within the scope of the invention.

[0145] For example, in forms of the invention in which the operating head 1200 is not laterally moveable toward and away from the frame 1100, the operating head 1200 may be fixedly attached to the frame, such as by attaching a bracket of the operating head 1200 to the frame 1100. Alternatively, the operating head 1200 may be rotatably attached to the frame 1100, such as by rotatably attaching a bracket of the operating head to a vertical shaft mounted on the frame, or by rotatably attaching a bracket of the frame 1100 to a vertical shaft of the operating head 1200, as will be appreciated by a person skilled in the art.

Claims

WHAT WE CLAIM IS:

1. An apparatus for pulling a post or stump from a ground, the apparatus comprising: a drive system; a frame 1100; and an operating head 1200 attached to the frame and comprising: a jaw assembly 1250 comprising a non-hinging digging jaw 1252 comprising a distal end for piercing the ground, and a hinged jaw 1255 that is moveable toward and away from the digging jaw 1252; a hammer 1240 moveable between a raised, retracted position and a lowered, impact position; wherein the drive system is operatively connected to the frame or operating head and comprises a power source and an actuation system operatively connected to the hammer 1240 to power the hammer to reciprocate between the retracted position and the impact position, wherein in the impact position, the hammer impacts on the jaw assembly 1250 to hammer the distal end of the digging jaw 1252 downwardly into the ground.

2. The apparatus of claim 1, wherein the hammer 1240 comprises a substantially vertically orientated reciprocating ram and an anvil located at a lower end of the ram.

3. The apparatus of claim 2, wherein the ram is a hydraulically powered ram.

4. The apparatus of any one of the preceding claims, wherein the hammer 1240 reciprocates up and down along a substantially vertical virtual y-axis.

5. The apparatus of any one of the preceding claims, wherein the operating head 1200 is slidably attached to a substantially vertical elongate support shaft 1230 that is attached to the frame 1100 such that the operating head is vertically moveable up and down relative to the frame 1100.

6. The apparatus of any one of claim 5, wherein the operating head 1200 is rotatable about a virtual vertical axis that is substantially parallel with a longitudinal axis of the support shaft 1230.

7. The apparatus of claim 5 or 6, wherein a first linearly extendable actuating arm 1205 attached to the operating head 1200 and to a stationary element of the apparatus causes the operating head 1200 to slide up and down along the support shaft 1230.

8. The apparatus of claim 7, wherein the stationary element 1215 is fixedly attached to the support shaft 1230.

9. The apparatus of claim 7 or 8, wherein the support shaft 1230 is rotatably attached to the frame 1100.

10. The apparatus of claim 9, comprising a second linearly extendable actuating arm 1206 attached to the frame and the support shaft 1230 to pivot the support shaft and operating head 1200 relative to the frame 1100.

11. The apparatus of any one of the preceding claims, wherein the operating head 1200 is laterally moveable toward and away from the frame 1100.

12. The apparatus of claim 11, wherein the frame comprises a connection arm 1140 that connects the operating head 1200 to the frame, and wherein the apparatus also comprises a directional adjustment system comprising a pair of linearly extending directional actuating arms 1143a, 1143b attached to the frame 1100 and to the connection arm 1140, such that extension of one of the directional actuating arms and retraction of the other of the directional actuating 1143a, 1143b arms causes the connection arm 1140, and therefore the operating head 1200, to rotate to one side of the frame 1100.

13. The apparatus of claim 11, wherein the frame comprises an extension arm 1140a and a linearly extendable actuating arm 1101 that is powered by the drive system to laterally extend from and retract toward the frame 1100 and that is fixedly or rotatably attached to the frame and to one end of the extension arm.

14. The apparatus of any one of the preceding claims, wherein the digging jaw 1252 comprises a contact surface from which a plurality of teeth 1253 project outwardly toward the hinged jaw 1255.

15. The apparatus of any one of the preceding claims, wherein the hinged jaw 1255 comprises a distal end comprising a prong 1255a.

16. The apparatus of claim 15, wherein the hinged jaw 1255 is hinged from the digging jaw 1252.

17. The apparatus of claim 16, comprising a fourth linearly extendable actuating arm 1257 rotatably attached to the hinged jaw 1255 and to a bracket of the jaw assembly 1250 or the digging jaw 1252, and wherein extension or retraction of the fourth actuating arm 1257 opens or closes the hinged jaw 1255.

18. The apparatus of any one of the preceding claims, wherein the jaw assembly 1250 comprises an impact element 1243 located between the hammer 1240 and a proximal end of the digging jaw 1252 and wherein the impact element 1243 is slidably attached to the operating head 1200 to allow the jaw assembly 1250 to move toward and away from the operating head.

19. The apparatus of claim 18, wherein the impact element 1243 is attached to a bracket 1251 of the jaw assembly 1250, and is slidably mounted on a pair of opposing guide supports 1245 that extend between the jaw assembly bracket member 1251 and the operating head body 1220.

20. The apparatus of claim 19, wherein each of the pair of opposing guide supports 1245 extends through a respective receiving aperture 2143a in the impact element 1243 and comprises a lower locking element 1246 located beneath the impact element to attach the guide supports 1245 to the impact element 1243, and wherein the operating head 1200 comprises a support element 1223 comprising a pair of support element openings 1244 that each slidably receive a respective one of the guide supports 1245 therein and wherein each of the opposing guide supports 1245 comprises an upper locking element 1248 located above the support element 1223.

21. The apparatus of any one of claims 7, 10, 12, and 16, wherein any one or more of the actuating arms 1101, 1143a 1143b, 1205, 1257 is hydraulically, electrically, or mechanically powered by the drive system.

22. The apparatus of any one of the preceding claims, comprising a support leg 1210 to contact the ground during use and support the operating head 1200 at a distance above the ground.

23. The apparatus of any one of the preceding claims, comprising a receiver 1130 to receive instructions from a remote controller 1180, and to transmit the received instructions to a processor of the apparatus, the processor being programmed to operate the actuation system according to the received instructions.

24. The apparatus of any one of the preceding claims, comprising a screen 1260 that is attached to the operating head 1200 and at least partially shrouds the hammer 1240.

25. The apparatus of any one of the preceding claims, wherein the actuation system is a hydraulic system.

26. The apparatus of any one of the preceding claims, wherein the frame 1100 comprises a hitch 1105 to attach the apparatus 1000 to an agricultural vehicle, such as a tractor.

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