AU2020201534B2

AU2020201534B2 - Lifting Device

Info

Publication number: AU2020201534B2
Application number: AU2020201534A
Authority: AU
Inventors: Graeme Davis
Original assignee: Graeme Davis
Current assignee: Graeme Davis
Priority date: 2019-03-01
Filing date: 2020-03-02
Publication date: 2025-02-27
Anticipated expiration: 2040-03-02
Also published as: AU2022100125A4; AU2020201534A1

Abstract

The invention relates to a post anchor removal device for removing a post anchor having a tubular body with an open end. The post anchor removal device includes: a rigid support which defines a fulcrum and a lever which is rotatable about the fulcrum 5 through a substantially vertical plane. The lever extends on either side of the fulcrum to define a first portion on one side and a second portion on the other side, whereby downward movement of the first portion results in upward movement of the second portion. The second portion is connected to a gripping arrangement for at least partial insertion into the body of a post anchor. The gripping arrangement is expandable from 10 an insertion condition in which the gripping arrangement is contracted for insertion into the open end of the tubular body, to a gripping condition in which the gripping arrangement is expanded for gripping the inside surface of the tubular body. The gripping arrangement is connected to the second portion of the lever for applying a lifting load to the gripping arrangement during rotational movement of the lever. In 15 use, with the gripping arrangement inserted into the tubular body of a post anchor and in the gripping condition, the gripping arrangement is operable such that the lifting load tends to drive the gripping arrangement into gripping engagement with the inside surface of the tubular body of the post anchor. 20 Figure 1 CN-C IC)N CNC 000 0 V CC IC)

Description

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CC IC) LIFTING DEVICE PRIORITY CROSS REFERENCE

[0001] The present application claims priority to Australian provisional patent application 2019900670 filed 1 March 2019, the entire disclosure of which is hereby incorporated by reference.

TECHNICAL FIELD

[0002] The present invention relates to the field of lifting devices. More particularly, a post anchor removal device for removing post anchors from the ground. The invention also relates to a gripping device suitable for use in the removal of post anchors and also for lifting or removing other types of objects.

BACKGROUND OF INVENTION

[0003] The following discussion of the background to the invention is intended to facilitate an understanding of the invention. However, it should be appreciated that the discussion is not an acknowledgement or admission that any of the material referred to was published, known or part of the common general knowledge as at the priority date of the application.

[0004] When anchoring a post in the ground, it is common for the base of the post to be tapered, sharpened or otherwise configured for piercing the surface of the ground such that the post can be pushed or driven into the ground to an anchored position more easily than if base was not tapered or so configured. These types of posts are therefore 'self-anchoring' because they are not otherwise supported or anchored by a base.

[0005] Self-anchoring posts which are known in the industry as "star pickets" can be removed from the ground by gripping the surface of the star pickets and applying an upward force to pull the base of the star pickets from the ground. Various devices have been developed to assist in the removal of these star pickets and for example, the Applicant of the present invention has obtained grant of Australian Innovation Patent No. 2009100954 which relates to a star picket removal device.

[0006] Although star pickets can be used for both permanent or semi-permanent applications, they are not as convenient for applications in which a star picket is required to be removed periodically or where star picket removal is required to be relatively easy, such as without any significant mechanical assistance. This might occur for example, with road signs that are periodically damaged by vehicle collision, or more particularly, with posts that are used for temporary fencing or temporary buildings. With such requirements, post anchors can be employed which in some forms consist of a hollow sleeve for receiving the base of a post and usually three or four tapered plates welded to the outside of the hollow sleeve which form a sharp leading end of the anchor for piercing the surface of the ground as the anchor is pushed or driven into the ground.

[0007] A post anchor is driven into the ground to the point at which the open end of the sleeve is substantially flush with or just above the surface of the ground, thereby providing an anchor into which the bottom or base of a post can be inserted to support the post in an upright position. The bottom or base of the post can simply rest within the sleeve, or it can be more securely fixed within the sleeve by inserting a wedge between the bottom or base of the post and the facing surface of the sleeve, or openings can formed both in the bottom or base of the post and the sleeve for alignment and receipt of a pin. Use of a post anchor enables posts to be erected and removed with ease.

[0008] Post anchors are difficult to remove from the ground when they are no longer required to support a post. This is because there is usually little or none of the anchor which is above ground for gripping and if a portion is available for gripping, that portion is usually cylindrical and therefore difficult to grip and lift. Often removal requires the ground around the top part of the anchor to be removed or excavated so that access to the anchor can be made and then crowbars, shovels or similar equipment are used to dig the anchor out. Given the difficulty in removing the anchors from the ground, they are often left in place and abandoned, which creates the possibility of obstruction and which can be unsightly. There is also the lost cost of the anchor and the potential for injury to persons who may trip over the anchor, or fall on the anchor.

[0009] While a post anchor may be flush with or recessed into the ground such that it provides no immediate obstruction to vehicles or pedestrians, often the anchor does project above the ground surface sufficiently to present a problem, or at least an annoyance, to vehicles or pedestrians. Even if the post anchor is recessed into the ground such that it provides no obstruction to vehicles or pedestrians, over time the anchor can move and if the movement is upwards, it can then form an obstruction of the unwanted kind discussed above.

[0010] The present Applicant has therefore sought to develop a post anchor removal device that is suitable to remove post anchors from the ground, in a manner that is easier than the methods known to the Applicant to date.

[0011] Before turning to a summary of the invention, it will be useful to provide an explanation of some of the terms what will be used to define the spatial relationship of various parts thereof. In this respect, spatial references will generally be based upon a lifting device for removing a post anchor which is embedded in the ground. References herein to lifting will generally be based upon removal of a post anchor embedded in a horizonal ground surface. With this environment as basis, some parts of the invention may be defined with reference to the ground surface allowing reference to terms such as "horizontal", "vertical", "up" or "upper" and "lower" or "downwards". Reference to 'lifting'will therefore generally be understood as meaning lifting in an upward direction although will be appreciated that a post anchor could be embedded in an inclined or even vertical surface. In this case removal or'lifting'of the post anchor will typically occur perpendicularly to the surface in which the anchor is embedded.

SUMMARY OF INVENTION

[0012] According to a first aspect of the present invention, there is provided a post anchor removal device for removing a post anchor having a tubular body with an open end, the post anchor removal device including: a rigid support which defines a fulcrum a lever which is rotatable about the fulcrum through a substantially vertical plane the lever extending on either side of the fulcrum to define a first portion on one side and a second portion on the other side, whereby downward movement of the first portion results in upward movement of the second portion the second portion being connected to a gripping arrangement for at least partial insertion into the body of a post anchor the gripping arrangement being expandable during rotation of the lever from an insertion condition in which the gripping arrangement is contracted for insertion into the open end of the tubular body, to a gripping condition in which the gripping arrangement is expanded for gripping the inside (such as the inside surface) of the tubular body the extent of rotational movement of the lever being sufficient for the gripping arrangement to expand from the insertion condition to the gripping condition and for the gripping arrangement to be lifted in the gripping condition for lifting the post anchor.

[0013] The present invention advantageously provides a post anchor removal device that can engage the inside surface of a post anchor to remove an embedded post anchor from the ground. The benefit of this arrangement, is that the hollow body of the post anchor is almost always available for engagement and thus the inside surface of the hollow body presents an accessible surface for which to engage the post anchor. This is different to other surfaces of an embedded ground anchor, which might be obscured by or embedded within the ground, or which might present only a minimum surface for gripping engagement.

[0014] The present invention also advantageously allows the use of mechanical advantage in employing a lever to effectively jack-up the post anchor from the ground. The length of the first portion of the lever can be significantly longer than the second portion, and in practice, the ratio between the first portion and the second portion preferably is greater than 1:4, and more preferably is in the region of about 1:8. The ratio can however be greater than this to provide for greater mechanical advantage.

[0015] The invention broadly contemplates gripping the inside surface of the tubular body of the post anchor and the gripping can be by any suitable arrangement. Some post anchors include openings in the wall of the tubular body for locating pins or split pins or the like, and the device of the invention could include pins or suitable abutments to engage within one or more of the openings for the purpose of lifting an embedded post anchor from the ground.

[0016] Alternatively, other engaging features can be employed in a device according to the invention to engage suitable features of the inside of the tubular body of a post anchor to which the device is to be employed.

[0017] However, in prototypes developed to date, the device of the invention employs friction to grip the inside surface of the tubular body of the post anchor. It has been found that in a device according to the invention, sufficient frictional load can be exerted by the gripping arrangement of the device to lift a post anchor from the ground. A major benefit of using friction to engage the inside surface of a post anchor, is that there is no physical connection which needs to be manually made prior to the anchor being lifted from the ground. Rather, the gripping arrangement merely needs to engage the inside surface of the post anchor with sufficient force that it is lifted in the manner required. Accordingly, in an embodiment of the invention, the gripping arrangement is arranged to grip the inside surface of the tubular body of the post anchor by friction.

[0018] The manner of exerting a frictional load against the inside surface of a post anchor can take various suitable forms, but in some forms of the invention developed by the applicant, the gripping arrangement includes a pair of grippers is provided which are moveable between the insertion condition and the gripping condition and each of the pair of grippers has a gripping surface which is arranged for frictional engagement with the inside surface of the post anchor. The grippers typically will be metallic grippers, and to enhance frictional engagement with the inside surface of the post anchor, the gripping surfaces can either be curved or serrated surfaces, or both.

[0019] In the above forms of the invention, the grippers can be moved into frictional engagement with the inside surface of the post anchor in any suitable manner and in some forms, the grippers are moveable relative to one another in opposite directions from the insertion condition to the gripping condition. That movement can be rotational movement and for example, the device of the invention could include a pair of grippers formed as cams that move upwardly and outwardly from the insertion condition to the gripping condition. Upward movement of the cams could increase the frictional load applied by the grippers against the inside surface of the post anchor until such time as the frictional load is sufficient for the device to commence lifting of the anchor out of the ground.

[0020] Alternatively, the gripping arrangement can include a pair of elongate arms that are rotatably connected at one end to the second portion of the lever and at the other end, to one of a pair of grippers. Each gripper can also be rotatably mounted at a position spaced from the rotatable connection with the respective arm and in this arrangement, the grippers can be driven to rotate about the rotatable mounting by the arms during rotational movement of the lever.

[0021] In the above forms of the invention, the grippers can be rotatably mounted along a common axis. Furthermore, the grippers can rotate on a common plane. Moreover, in the gripping condition, the rotatable connection between the arms and grippers is between the rotatable connection between the arms and the second portion of the lever and the rotatable mounting of the grippers. Typically, there will be a much greater difference between the rotatable connection between the arms and the second portion as compared to the rotatable connection between the arms and the second portion and the rotatable mounting.

[0022] In some forms of the invention, the spacing or distance between the rotatable connection between the arms and the second portion and the rotatable mounting of the grippers is constant throughout rotation of the lever. In that arrangement, the grippers are caused to rotate about the rotatable mounting upon relative movement between the rotatable connection between the arms and the grippers and the rotatable mounting. For this, the arms can be caused to pivot outwardly about the rotatable connection to the second portion as the lever is rotated to contract the gripping arrangement to the insertion condition. The arms can pivot in the opposite direction once the lever is rotated in the opposite direction to expand the gripping arrangement to the gripping condition.

[0023] In some forms of the invention, the rotatable mounting of the grippers is made to a sliding member that is slidably connected to the rigid support, whereby each of the second portion, the pair of arms, the sliding member and the grippers move together during sliding movement of the sliding member relative to the support. In contrast, rotational movement of the grippers between the insertion and gripping conditions occurs when the second portion and the pair of arms move relative to the sliding member. This occurs when the sliding member is prevented from sliding movement on the support and this can be achieved by the sliding member engaging an abutment which is positioned at an appropriate position relative to the support to prevent further sliding movement. The abutment can be adjustable on the support to alter the position at which sliding movement of the sliding member is terminated.

[0024] The length of the rigid support can be adjustable in order to raise the gripping arrangement relative to a bottom or base end of the support. This can be important in the event that a single rotation of the lever does not cause the post anchor to be lifted sufficiently from the ground for its removal. In those circumstances, the length of the rigid support can be adjusted to raise the gripping arrangement, so that a further rotation of the lever can raise the gripping arrangement further and until the post anchor is raised sufficiently that it can be removed from the ground. Adjustment of the length of the rigid support can be by any suitable arrangement and in some forms of the invention, the rigid support is telescopic for adjustment purposes.

[0025] Where the rigid support is formed as a telescopic support, the support can include an inner post and an outer sleeve or tube and openings can be formed in both of the post and tube through which a pin can be inserted. Thus, to adjust the length of the support, the outer tube can be telescopically shifted relative to the inner post until such time as openings of the tube and post are aligned and a pin thereafter can be inserted through the openings to maintain the relative position between the tube and post. Openings can be provided for a range of different height adjustments, thereby ensuring that the removal device has sufficient lifting capability of the gripping arrangement to remove a post anchor from the ground.

[0026] According to a second aspect of the present invention, there is provided a post anchor removal device for removing a post anchor having a tubular body with an open end, the post anchor removal device including: a rigid support which defines a fulcrum a lever which is rotatable about the fulcrum through a substantially vertical plane the lever extending on either side of a fulcrum to define a first portion on one side and a second portion on the other side, whereby downward movement of the first portion results in upward movement of the second portion the second portion being connected to a gripping arrangement for at least partial insertion into the body of a post anchor the gripping arrangement being expandable from an insertion condition in which the gripping arrangement is contracted for insertion into the open end of the tubular body, to a gripping condition in which the gripping arrangement is expanded for gripping the inside surface of the tubular body the gripping arrangement being connected to the second portion of the lever for applying a lifting load to the gripping arrangement during rotational movement of the lever, the gripping arrangement including a pair of grippers which are movable between the insertion condition and the gripping condition and each of the pair of grippers having a gripping surface arranged for frictionally engaging and gripping the inside surface of the tubular body of the post anchor, the grippers being rotatably connected to each other at a rotatable connection and being movable about the rotatable connection between the insertion condition and the gripping condition, the grippers including proximal and distal ends and the rotatable connection between the grippers being located at the distal ends of the grippers, wherein, in use, with the gripping arrangement inserted into the tubular body of a post anchor and in the gripping condition, the gripping arrangement is operable such that the lifting load tends to drive the gripping arrangement into gripping engagement with the inside surface of the tubular body of the post anchor.

[0027] The second aspect relates to an alternative configuration of the invention whereby movement between the expanded and contracted conditions is partially independent of the lever. For example, rotational movement of the lever may still operate to urge the gripping arrangement toward (or maintain the gripping arrange in) the expanded condition. However, in the second aspect of the present invention, the gripping arrangement may also move between the expanded and contracted conditions without lever rotation.

[0028] According to this second aspect of the invention, movement of the gripping arrangement between the contracted and expanded conditions does not necessarily occur during rotation movement of the lever. That is, the gripping arrangement may already be in the expanded condition before the user rotates the lever.

[0029] References throughout the specification to 'distal' and 'proximal' will be respectively understood in the context of the gripping arrangement which has a proximal end connected to the source of the lifting load and extends to a distal end which is insertable into a post anchor.

[0030] According to a particular embodiment of the invention, the grippers have an elongate, arcuate shape and the gripping surfaces being formed toward the distal ends.

[0031] The gripping arrangement may comprise a linkage mechanism connecting the second portion of the lever to a connection point on each gripper, the connection point on each gripper being spaced from the rotatable connection of the grippers. The position of the connection points on the grippers may vary. However, in a particular form of the invention, the connection points are located at proximal ends of the grippers.

[0032] According to a particular embodiment, contractive movement of the respective connection points toward one another corresponds to expansive movement of the respective gripping surfaces into the expanded condition.

[0033] The grippers may include proximal ends connected to the second portion of the lever via the linkage mechanism and distal ends which are rotatably connected to one another and configured for insertion into the body of a post anchor. As discussed in the foregoing, each gripper may be provided with a curved and serrated gripping face. Movement of the gripper proximal ends toward one another causes the pair of gripping faces to rotate apart from one another into the expanded condition whereupon an inner surface of a post anchor body may be gripped.

[0034] It will be appreciated that, in certain embodiments of the invention, the grippers may therefore be connected only to each other and to the linkage mechanism i.e. the grippers are not connected to a slide mechanism or to the rigid support in any other way. The distal ends of the grippers may therefore define a free end of the gripping arrangement.

[0035] According to a particular embodiment of the invention, the grippers have an intersecting configuration in which the respective connection points and the respective gripping surfaces are located on opposite sides of an intersection and whereby contractive movement of the connection points toward one another corresponds to expansive movement of the gripping surfaces into the expanded condition.

[0036] The intersecting configuration may involve the grippers crossing over one another. In embodiments where the grippers are curved, the intersecting configuration of the grippers may create a fish-shaped profile. The grippers may each be formed by a pair of plates and the plates of one gripper are interwoven with the plates of the other gripper in order to provide the intersecting configuration.

[0037] The intersecting configuration advantageously provides one means by which movement of the gripping arrangement to the expanded condition can be achieved by a pulling or lifting load which is applied to the gripping arrangement by the second portion of the lever.

[0038] For example, the linkage mechanism may be arranged in such a way that lifting load applied by the second portion of the lever operates to contract the connection points toward one another which urges expansive movement of the gripping surfaces. Once the gripping surfaces have expanded to engage the inside of the post anchor the expanded condition is achieved. Thereafter, further rotational movement of the gripping arrangement is restricted by the post anchor and lifting load applied by the linkage mechanism acts as an upward pulling load upon the post anchor.

[0039] The manner in which linkage mechanism converts lifting load applied by the second portion of the lever into contractive movement of the gripper connection points may be achieved in a variety of configurations. For example, a pair of rotatably connected elongate arms may connect the second portion of the lever to each of the connection points and whereby upward movement of the second portion of the lever urges the elongate arms toward a parallel condition and thereby urges the connection points toward one another.

[0040] According to an alternative embodiment of the invention, the linkage mechanism includes a drive linkage which is connected to the second portion of the lever and the linkage mechanism also includes a pair of link arms which are rotatably connected, at a first end, to the drive linkage and are rotatably connected, at a second end, to the respective connection points on each gripper. In a particular embodiment, the first and second ends of the link arms comprise proximal and distal ends of the link arms respectively.

[0041] The lifting load applied to the first (e.g. the proximal) ends of the link arms may, in some instances, drive movement of the gripping surfaces toward the expanded condition. In other instances, the gripping surfaces may already be positioned in the expanded condition when lifting load is applied.

[0042] For example, in use, the grippers are inserted into a pole anchor in the contracted condition. In some instances, the grippers may remain at rest in the contracted condition until application of lifting load drives movement of the grippers to the expanded condition in which the pole anchor is engaged. In this configuration, lifting load applied to the rotatably connected first ends of the link arms urges the second ends of the link arms to close or contract toward one another. In turn, the connection points of the grippers which are rotatably connected to the second ends of the link arms are also urged together thereby urging the gripping surfaces to move apart from one another, toward the expanded condition.

[0043] In alternative instances, the grippers may naturally urge toward the expanded condition under their own weight. That is, the weight of the grippers and link arms may induce rotation about the rotatable connection at the proximal end of the link arms. In use, the user may manually (under finger pressure) move the grippers to the contracted condition for insertion into the pole anchor. Once finger pressure is released the grippers and link arms may fall under their own weight into the expanded condition. Thereafter, application of the lifting load will maintain the gripping arrangement in the expanded condition whilst simultaneously lifting the grippers (and the pole anchor engaged therewith) in the upward direction of the lifting load.

[0044] In a particular embodiment of the invention, the rotatable connection between the pair of link arms moves towards the rotatable connection between the grippers for contractive movement of the grippers and the rotatable connection between the pair of link arms moves away from the rotatable connection between the grippers for expansive movement of the grippers.

[0045] The link arms can be linear, elongate, curved, right-angled or a combination of one or more of these or other configurations. In a particular form of the invention, the link arms are generally L-shaped and the connections to the drive linkage and the respective connection points on each gripper are made at opposite ends of the link arms.

[0046] The use of a linkage mechanism comprising a single drive linkage rotatably connected to the pair of link arms may advantageously provide a single lifting point at the rotatable connection of the grippers. This may help ensure equal rotational load is applied to the grippers which, in turn, may facilitate improved gripping of the post anchor body.

[0047] The rotatable connection between the grippers can be located at a variety of positions along the grippers. In one embodiment, the rotatable connection is located at an approximately mid-point along the length of the grippers. In this embodiment, the intersection between the grippers corresponds to the location of the rotatable connection. In this embodiment, the rotatable connection is positioned between the connection points and the gripping surfaces to provide a scissor-type configuration wherein contraction of the connection points causes expansion of the gripping surfaces.

[0048] In an alternative embodiment, the rotatable connection is located at a distal end of the grippers and the gripping surfaces are positioned between the rotatably connected distal ends and the gripper connection points which are rotatably connected to the link arms. In this embodiment, the intersection between the grippers is a floating crossover which moves along the length of the grippers. For example, in the expanded condition when the connection points are contracted together, the intersection is adjacent the connection points. In the expanded condition when the connection points are spaced apart from one another and the grippers are moved to the contracted position, the gripper intersection is shifted closer to the distal end of the grippers.

[0049] The drive linkage may be configured to adjustment of the length between the second portion of the lever and the grippers. For example, the drive linkage may comprise a telescopic tube arrangement. Alternatively, in an embodiment of the invention, the drive linkage is connectable to the second portion of the lever at various points along the length of the drive linkage to facilitate adjustment of the distance between the second portion of the lever and the grippers.

[0050] This form of the invention advantageously allows a user to adjust the length of the chain between the lever and the grippers. This facilitates removal of post anchors of varying depth. Furthermore, during operation of the remover,

[0051] The drive linkage may, for example, comprise a chain and the second portion of the lever includes a hook portion configured for removable engagement with a chain-link of the chain.

[0052] Alternatively, the drive linkage may comprise a rigid member or a cable or other flexible connector. For example, according to a particular embodiment of the invention, the drive linkage comprises a rod that is fixed at one end to the second portion of the lever and that is fixed at the opposite end to the gripping arrangement.

[0053] The aforementioned first and second aspects of the present invention relate to a gripping arrangement in which the lifting load is applied by the above discussed lever and rigid support arrangement. However, it will be appreciated that the gripping arrangement of the present invention may be used with a variety of alternative lifting means. Accordingly, another aspect of the present invention relates to a gripping device only, without limitation to a particular type of lifting means.

[0054] In this regard, a third aspect of the present invention provides an expandable gripping device for removing a post anchor having a tubular body with an open end, the expandable gripping device including: a pair of grippers which are movable between an insertion condition in which the grippers are contracted for insertion into the open end of the tubular body, to a gripping condition in which the grippers are expanded for gripping an inside surface of the tubular body, each of the pair of grippers having a gripping surface arranged for frictionally engaging and gripping the inside surface of the tubular body, the grippers being rotatably connected to each other at a rotatable connection and being movable about the rotatable connection between the insertion condition and the gripping condition, the grippers including proximal and distal ends and the rotatable connection between the grippers being located at the distal ends of the grippers, wherein the grippers are connectable to a lifting arrangement for applying a lifting load to the grippers, and wherein, in use, with the grippers inserted into the tubular body of a post anchor and in the gripping condition, the grippers are operable such that the lifting load tends to drive the grippers into gripping engagement with the inside surface of the tubular body of the post anchor.

[0055] The gripping device according to this third aspect of the invention may be similar in configuration to the gripping arrangement of the second aspect of the invention.

[0056] The gripping device may be lifted using lifting means such as the above discussed lever configuration. However, in contrast to the first and second aspects, the gripping device of the third aspect may also be coupled to a variety of lifting means other than a lever arrangement. The gripping device may also be used in a variety of applications other than post anchor removal. For example, the gripping device may be coupled to a crane, forklift, load picker, backhoe or other excavation machinery, gantry and winch or other overhead lifting device. The gripping device is suitable to be coupled to a winch that is fixed to a 4WD for example. Coupling may occur by connecting the coupling point to the lifting device via a suitable linkage, for example a chain, cable, shaft, beam or rope. An appropriate linkage can be selected based on the mass of the load intended to be lifted.

[0057] The gripping device may be suitable for use in lifting and removing post anchors in the manner discussed above with reference to the second aspect of the invention. Additional and alternative applications include lifting of concrete or steel access covers such as manhole covers, sewer or drain covers or hatch lids. The gripping device may be used in construction applications to lift and relocate concrete blocks and for lifting and placing concrete or steel road barricades or bollards.

[0058] Specific features of the gripping arrangement discussed above with reference to the second aspect may also be applicable in the third aspect of the invention.

[0059] The grippers may have an elongate arcuate shape and the gripping surfaces may be formed toward the distal ends. Each gripping surface may include a connection point which is spaced from the rotatable connection of the grippers. In a particular embodiment, contractive movement of the respective connection points toward one another corresponds to expansive movement of the respective gripping surfaces into the expanded condition.

[0060] The arcuate shape of the grippers may advantageously provide for curved gripping surfaces which increase the angular range through which the gripping surfaces will engage the opening of the liftable object. In the expanded position, the pair of arcuate-shaped grippers may define a generally tear-drop profile. In the contracted position, the grippers may define a generally oval profile.

[0061] In one form of the third aspect of the invention, the pair of grippers have an intersecting configuration in which the respective connection points and the respective gripping surfaces are located on either side of an intersection which is spaced from the rotatable connection and whereby contractive movement of the connection points toward one another corresponds to expansive movement of the gripping surfaces into the expanded condition.

[0062] In a particular form of the invention, the gripping device further includes a pair of link arms which are rotatably connected to one another at a first end and are rotatably connected, at a second end, to the respective connection points on each gripper. In one embodiment, the rotatable connection between the pair of link arms moves towards the rotatable connection of the grippers during contracting movement of the grippers and the rotatable connection between the pair of link arms moves away from the rotatable connection between the grippers during expansive movement of the grippers.

[0063] In one form of the invention, the link arms are elongate. Alternatively, the link arms may be curved. In a particular embodiment of the invention, the link arms have a generally right-angled profile. In an alternative embodiment of the invention, the link arms may be flexible, for example the link arms may consist of a pair of cables which connect the coupling point to the grippers. However, in a preferred form of the invention, the link arms are rigid and are also formed form the same material as the grippers.

[0064] The coupling point of the gripping device may be located at the rotatable connection between the first ends of the link arms. The rotatable connection between the pair of link arms may be provided by a suitable connector, for example a shackle. The shackle bolt may extend through aligned openings in the first ends of the link arms and the shackle loop may define a connection point to which a lifting device may be connected.

[0065] The gripping device may further include a lifting link including a proximal end and a distal end. The proximal end of the lifting link may provide the coupling point. For example, a lifting chain may be connected to the proximal end of the lifting link via a connector such as a bolt or shackle such as a bow-shackle or D-shackle. The distal end of the lifting link can be rotatably connected to the first ends of the link arms. The lifting link may include a single distal end which is rotatably connected to both link arms. Alternatively, the lifting link may include a pair of distal ends which are rotatably connected respectively to each link arm. In this instance, the lifting link is rotatably connected to each of the link arms but the link arms are not necessarily rotatably connected to each other.

[0066] The lifting link may itself comprise a shackle or could comprise any other connecting member or linkage. According to a particular embodiment, the lifting link is a rotatably connected to the first (i.e. proximal) ends of the link arms via a pin. The opposite end of the lifting link is then, in use, connected to a lifting chain via a separate D-shackle. In this manner, the lifting link can remain permanently attached to the link arms and provide a coupling point to which a chain or other lifting member can be conveniently attached. The lifting link could in certain applications be replaced by a conventional shackle. However, the lifting link can provide a larger opening than is typically provided by conventional shackles. In this way, the larger opening facilitates convenient connection to a variety of shackles or other connectors.

[0067] The gripping device according to the third aspect of the invention may therefore define an arrangement of four-linkages comprising a pair of grippers and a pair of link arms.

[0068] The four linkages are connected via four rotatable connections comprising one rotatable connection between the distal ends of the grippers, one rotatable connection between the proximal ends of the link arms and a pair of rotatable connections between the proximal ends of the grippers and the distal ends of the link arms.

[0069] The arrangement may be generally symmetrical. When the gripping device is in its operational orientation, the rotatable connection of the link arms and the rotatable connection of the grippers may lie and move along a generally vertical axis. Similarly, the pair of rotatable connections between the distal ends of the link arms and the proximal ends of the grippers may, in use, lie on and move along a generally horizontal axis.

[0070] It will be appreciated that the gripping device according to the third aspect of the invention may be suitable for use in lifting any object with an appropriately sized opening in which the gripping device can be inserted. A variety of different sized gripping devices may be provided for a variety of different applications and to suit different sized openings in different objects.

[0071] According to a particular embodiment of the invention, the gripping device is formed from hardened steel. However, it will be appreciated that other materials may be suitable. For example, other types of hard metals or alloys such as magnesium or tungsten alloys.

BRIEF DESCRIPTION OF DRAWINGS

[0072] In order that the invention may be more fully understood, some embodiments will now be described with reference to the figures in which:

[0073] Figure 1 is a side view of a post anchor removal device according to the present invention;

[0074] Figure 2 illustrates the telescopic base of the post anchor removal device illustrated in Figure 1;

[0075] Figure 3 is a rear perspective of the second embodiment of the device shown in Figure 1;

[0076] Figure 4 is a front view of a gripping arrangement of the device of Figure 1, when inserted into the open end of a post anchor;

[0077] Figure 5 is a front view of a portion of the gripping arrangement shown in Figure 4;

[0078] Figure 6 is a front view of a portion of the gripping arrangement of Figure 5 showing the gripping arrangement in a fully contracted position;

[0079] Figure 7 is a front view of a portion of the gripping arrangement of Figure 5 showing the gripping arrangement in a fully expanded position;

[0080] Figures 8 and 9 are perspective views of the device of Figure 1 with a chain of the gripping arrangement connected respectively shown in a lengthened position and a shortened position;

[0081] Figure 10 is a perspective view of a post anchor removal device according to an embodiment of the invention being used to remove a post anchor;

[0082] Figure 11 illustrates a gripping device according to an embodiment of the invention in use with a lifting machine to remove a post anchor;

[0083] Figure 12 illustrates a closer perspective of the gripping device and post anchor shown in Figure 12; and

[0084] Figure 13 is a side view of the perspective in Figure 12.

DETAILED DESCRIPTION

[0085] Figure 1 is a side perspective of a post anchor removal device 100 according to an embodiment of the present invention. The device 100 includes an elongate rigid support 111 extending from a flat base 112 to a fulcrum formed by an axle 113.

[0086] A lever 114 is rotatable about the axle 113 which extends through a top portion of rigid support 111. The axle 113 allows pivoting of the lever 114 about the axle 113 in a substantially vertical plane. Figure 1 illustrates lever 114 towards the bottom of a rotational stroke.

[0087] Turning to Figure 2, the rigid support 111 includes a telescopic arrangement for adjusting the height of the support 111. The rigid support 111 is a telescopic support in that the support 111 includes an inner post 145 and an outer tube 146. The inner post 145 includes a plurality of openings 147 which receive a pin 143. The outer tube 146 includes a single opening (which extends through both sides of the tube 146), and that opening can be aligned with the openings of the inner post 145 so that the pin 143 can extend through each of the inner post 145 and the outer tube 146. The function of the telescopic arrangement will be discussed in further detail below.

[0088] Turning to Figure 3, the axle 113 extends through a top portion of rigid support 111 and through a pair of plates 117 and 118 that form part of the lever 114. In this manner, lever 114 is pivotally mounted to rigid support 111 via the axle 113.

[0089] The lever 114 extends on either side of axle 113 to define a first portion 150 on one side of the axle 113 and a second portion 152 on the opposite side of axle 113. The first portion 150, in use, provides a handle for manually operating device 100. A second axle 121 connects the lever second portion 152 to a gripping arrangement 125 configured to grip and apply pulling load to a post anchor.

[0090] As illustrated in Figure 3, gripping arrangement 125 has a proximal end 125a connected to the second portion 152 and a distal end 125b configured for insertion into a post anchor. References herein to 'distal' and 'proximal' will generally be understood with reference to these two ends of the gripping arrangement 125.

[0091] Downward movement of the first portion 150 results in upward movement of second portion 152 on the opposite side of axle 113, and vice versa. Accordingly, downward movement of the first portion 150 results in upward lifting load being applied to gripping arrangement 125. As shown in Figure 1, the gripping arrangement 125 includes a hook bracket 154 which is pivotally connected to the second portion 152 via the axle 121. The hook bracket 154 includes a hook 156 which is best shown in Figure 8. The gripping arrangement 125 further includes a drive linkage which comprises a chain 158. The hook 156 engages with a chain-link in chain 158 and thereby connecting the chain 158 to the second portion 152.

[0092] The gripping arrangement 125 includes an expandable gripping device 159 at the distal end 125b of the gripping arrangement 125. The gripping device 159 is configured for at least partial insertion into a post anchor 34. The gripping device 159 comprises a pair of link arms 160 which are rotatably connected to a distal end of the chain 158 and a pair of grippers 130. The gripping device 159 is expandable from an insertion condition illustrated in Figure 6 in which the grippers 130 are contracted, to a gripping condition illustrated in Figure 7 in which the grippers 130 are expanded. Turning now to Figures 4 to 7, the gripping device 159 will be described in further detail.

[0093] Figure 4 illustrates the gripping device 159 of the gripping arrangement 125, when engaged with a post anchor 34. The post anchor 34 has a tubular body 35, which is effectively a cylindrical body, and three plates 36 which are welded to the outside surface of the body 35, and which are tapered to form a point for assisting the anchor 34 to be driven in to the ground. Figure 4 best shows the grippers 130 inserted into an open end 37 of the anchor 34.

[0094] In the insertion condition of the gripping device 159, the rotatable grippers 130 are contracted and can be lowered into the open end 37 of a post anchor 34. As shown in Figure 4, the pair of link arms 160 are generally L-shaped and are rotatably mounted at their proximal ends 162 to chain 158 via a pin 161. The distal ends 163 of link arms 160 are rotatably connected via pins 129 to connection points on the pair of rotatable grippers 130 engaged with an inside of the post anchor tubular body 35 and therefore partially obscured in Figure 4.

[0095] The grippers 130 are each formed from a pair of plates 131, best illustrated in Figure 4. The plates 131 are spaced apart so that the respective rotatable grippers are interweaved. This interweaving assists to prevent the individual plates 131 from twisting under load and ensures a greater spread of load to the internal surface of the post anchor 34.

[0096] The rotatable grippers 130 are intended to move between an insertion condition in which the grippers 130 are contracted for insertion into the open end of the tube of a post anchor, and a gripping condition in which the rotatable grippers 130 are expanded for gripping the inside surface of the post anchor. The fully contracted position is shown in Figure 6, while the fully expanded condition is shown in Figure 7.

[0097] The insertion condition requires some degree of contraction of the grippers 130. However, it will be appreciated that the grippers 130 need not necessarily be contracted to the fully contracted position shown in Figure 6 in order to achieve insertion into the post anchor 34.

[0098] As best shown in Figure 5, grippers 130 have a curved profile. As noted above, the plates 131 are interweaved. This provides an intersecting arrangement whereby the grippers 130 crossover one another at an intersection 166. In the illustrated embodiment, the intersection 166 is a floating intersection which shifts along the length of the grippers 130 during rotation of the grippers 130.

[0099] The distal ends 168 of grippers 130 are rotatably connected to one another by a pin 164. Each gripper 130 includes a serrated and curved gripping surface 144 configured for gripping engagement with an inside of post anchor tubular body 35. The gripping surface 144 of the grippers 130 is serrated to increase the level of grip between the grippers 130 and the inside surface of the post anchor 34. The connection points on the grippers 130 to which pins 129 are connected, are located at proximal ends 167 of the grippers 130. The pins 129 therefore rotatably connect the distal ends 163 of the link arms 160 with the proximal ends 167 of the grippers 130.

[0100] In an alternative form of the invention (not illustrated) a static intersection may be provided by locating a pin, in lieu of the pin 164, at a position between the proximal 167 and distal ends 168 of the grippers 130. In this alternative embodiment, the distal ends 168 of the grippers 130 would be free ends and could therefore expand outward to engage a post anchor.

[0101] The pair of link arms 160 and pair of grippers 130 define a four-link configuration rotatably connected by the four pins 161, 129, 129 and 164. It will be appreciated that lifting or lowering (vertical) movement of pin 161 will effect rotation in link arms 160. In particular, lifting load applied by chain 158 to pin 161 will move the proximal ends 162 of link arms 160 in the direction of the lifting load and thereby cause pins 129 at the distal ends 163 of link arms 160 to contract i.e. to move toward one another.

[0102] This contractive movement of pins 129 toward one another drives a corresponding contractive movement in the proximal ends 167 of grippers 130. The grippers 130 are thereby driven to rotate about pin 164. The portion of the grippers 130 on the proximal side of intersection 166 are moved closer together whilst the portion of grippers 130 on the distal side of intersection 166 are moved apart. The gripping surfaces 144 which are on a distal side of intersection 166 are thereby driven apart toward an expanded condition illustrated in Figure 7 which is suitable for gripping the inside surface of a post anchor.

[0103] Figure 5 illustrates the gripping arrangement 125 in an approximately neutral position in between the fully contracted position which is illustrated in Figure 6 and the fully expanded condition which is illustrated in Figure 7.

[0104] In the fully contracted condition illustrated in Figure 6, the proximal ends 162 of the link arms 160 collapse inward and abut the grippers 130. In this condition, the pin 161 rotatably connecting the link arms 160 and the pin 164 rotatably connecting the grippers 130 are as close to one another as the linkage configuration allows. The pins 129 rotatably connecting the link arms 160 to the proximal ends 167 of the grippers 130 are expanded as far apart from one another as is allowed by the linkage configuration. Gripping surfaces 144 are thereby in a fully contracted position and the intersection 166 between grippers 130 is shifted toward the distal ends 168 of the grippers 130.

[0105] In the fully expanded condition illustrated in Figure 7, the proximal ends 162 of link arms 160 have been pulled away from grippers 130 by chain 158 causing rotation of link arms 160 about pin 161 until the distal ends 163 of link arms 130 abut one another. The rotation of link arms 160 drives rotation of the grippers 130 about pin 164 whereby the proximal ends 167 of grippers 130 are driven together via their connection with pins 129 and the grippers 130 are thereby moved to their expanded condition wherein gripping surfaces 144 are fully expanded apart from one another. The intersection 166 of the grippers is shifted toward the proximal ends 167 of the grippers 130.

[0106] When hanging under its own weight, the natural state of the gripping arrangement 125 is the expanded configuration of Figure 7. If the gripping arrangement 125 is moved to the fully contracted condition illustrated in Figure 6, once the load applied to move it to that condition is removed (normally this will be finger pressure) the gripping device 159 will naturally return to the configuration of Figure 7 if there is no other impediment to that movement.

[0107] In use, the gripping device 159 is manually shifted toward the contracted condition of Figure 14 until the grippers 130 are sufficiently contracted to fit inside the post anchor which is anchored in the ground. Manual shifting the gripping device 159 toward the contracted condition may be performed by moving pins 164 and 161 toward one another, similar to the condition illustrated in Figure 14.

[0108] Once inserted into the post anchor, the gripping arrangement 125 will naturally expand under its own weight towards (but not necessarily reaching) the fully expanded condition illustrated in Figure 7. Once the grippers 130 engage the inside surface of the post anchor 34, further expansion is precluded. The size of the gripping device 159 is selected so that the inside surface of the post anchor 34 will be engaged by the grippers 130 before the gripping device 159 reaches the fully expanded condition illustrated in Figure 7.

[0109] With the inside surface of the post anchor engaged by the grippers 130, a lifting load is applied to the chain 158 by rotating the first portion 150 of lever 114 in a downward direction causing second portion 152 to rotate upward. Upward movement ofsecond portion 152 applies an upward load on chain 158 which tends to rotate the link arms 160 and forces the grippers 130 into more firm contact with the inside surface of the post anchor.

[0110] Thereafter, the lifting load applied by chain 158 applies an upward lifting force on grippers 130 and on the post anchor the inside of which is frictionally engaged by the gripping surfaces 144. Upon application of sufficient lifting load, the post anchor is thereby pulled upward from the ground. As the lever is further rotated downwardly, the gripping force between the anchor 34 and the grippers 130 increases and with sufficient force, further rotation of the lever 114 will commence lifting of the anchor 34 out of the ground.

[0111] If the first portion 150 of the lever reaches the bottom of a rotational stroke without the post anchor having been completely removed, the length of rigid support 111 can be increased using the telescopic arrangement discussed in the foregoing and illustrated in Figure 2. Once an initial lift has been completed, if further lift is required, the pin 143 can be removed from an opening 147 in the rigid support 11 and can be replaced at a different set of elevated openings 147. According to this arrangement, once the post anchor 34 has been lifted the maximum amount in a first lever rotation, if further lifting movement is required, the pin 143 is released from the bottom most set of openings 147 and the outer tube 146 is raised relative to the inner post 145 and the pin 143 is replaced through the next set of openings 147 in the inner post 145. By this relocation of the pin 143, the height of the support 111 is increased.

[0112] Once the pin 143 has been inserted into the next set of openings 147, the lever 114 can then be rotated downwardly again for a further upward shift of the post anchor 34. This relocation of the pin 143 can be repeated as required for each of the sets of openings 147 formed in the inner post 145. In the form of post anchor removal device 100 illustrated, the inner post 145 includes three sets of openings 147, although a greater number of sets of openings or a lesser number could be provided as required. Figure 2 shows the pin 143 located in the third set of openings 147.

[0113] Alternatively, rather than increase the height of the rigid support 111 in the manner discussed above, the present invention advantageously allows for the length of chain 158 between the second portion and the post anchor 34 to be shortened and for the lifting process to then be repeated. For example, Figure 8 shows the first portion 150 of the lever at approximately the bottom of a rotational stroke whilst post anchor 34 has not yet been pulled above the flat base 112. The user may disconnect chain 158 from hook 156 and lift the first portion150 to the top of a rotational stroke thereby lowering second portion 152 and lowering hook 156. The user then reconnects hook 156 to a chain-link in chain 158 which is closer to the post anchor.

[0114] Turning to Figure 9, the first portion 150 of the lever is then again rotated to the bottom of its rotational stroke in order to lift the post anchor 34 above the flat base 112 which is stood upon the ground. In some instances, the chain-shortening procedure may be quicker and generally more convenient as compared to adjusting the height of the rigid support 111.

[0115] Figure 10 illustrates the lifting device 100 being used to remove a post anchor 34 which is embedded into the ground. As shown, operator 170 applies a download load to lever 114 in order to lift the gripping arrangement 125 and the gripping device 159 which is engaged with post anchor 34.

[0116] Figures 1 - 9 illustrate the use of a convention D-shackle for connecting the link arms 160 to chain 158. However, as illustrated in Figures 10 - 13, the gripping device 159 can alternatively further include a lifting link 174 rotatably connected to the link arms 160 and providing a lifting point for the gripping device 159. The lifting link 174 has a generally U-shackle configuration but is customised to better suit the gripping device 159.

[0117] Turning to Figure 12, the lifting link 174 includes a pair of spaced apart parallel arms 176. The proximal ends 162 of the link arms 160 are received and secured via bolt 161 between distal ends of the parallel arms 174. The proximal ends of the parallel arms 176 are connected via a pin 178 which is connected to the chain 158 via a D-shackle 180.

[0118] Turning to Figure 13, the D-shackle 180 is received in the opening 182 between the parallel arms 176 of the lifting link 174. The opening 182 is sized to accommodate a variety of connectors, shackles or the like. In this way, the lifting link 174 provides a convenient connection point enabling a variety of chains or other drive members to be attached to the gripping device 159.

[0119] The openings in distal ends of parallel arms 174 correspond to the openings in the proximal ends 162 of the link arms 160. These openings also correspond to the size of bolt 161. Conventional shackles of sufficient size to provide an opening of comparable size to opening 182 will typically include large bolts which are undesirable or incompatible for use with the openings in the proximal ends 162 of link arms 160. The lifting link thereby provides a more customized connector as compared to the use of conventional shackles. Although, it is noted that conventional shackles may be used in place of the lifting link in some circumstances, as illustrated in Figures 1 - 9.

[0120] The illustrated embodiment of the present invention is advantageous in that the grippers 130 are connected to the lever only via the link arms 130 and chain 158. By using a flexible chain 158, the grippers 130 define a free-end of the gripping arrangement 125. This allows for the position of the grippers 130 to be conveniently moved around, relative to the rigid support 111, in order to align the grippers 130 with a post anchor. In turn, the speed and convenience of post anchor removal is improved.

[0121] It is to be noted that the chain 158 can be replaced by a rod that connects at one end to the lever second portion 152 and at the other end to the link arms 160 at the pin 161. This arrangement has the benefit that the rod is permanently connected to the lever and thus cannot be lost in contrast to the chain 158 that is releasably connected to the hook 156.

[0122] A removal device 100 according to the invention assists the easy removal of post anchors from the ground. The mechanical advantage provided by the length of the lever 114, means that the effort to remove a post anchor which is embedded in the ground is much less than by prior art arrangements. This means that post anchors are more likely to be removed when no longer required, rather than being left in place as presently occurs and which causes the problems as discussed earlier herein.

[0123] As discussed in the foregoing, the present invention may also relate to a gripping device 159 for removing post anchors which is liftable by variety of lifting means other than the lever arrangement illustrated in Figure 1. For example, the gripping device 159 may be connected to machinery such as a crane or excavating machine. This is exemplified in Figures 11 to 13 in which gripping device 159 is connected to a chain 158 which is connected to and lifted by an excavator 172. In particular, a proximal end of chain 158 is connected to an arm of excavator 172 by a D-shackle 180.

[0124] As will be appreciated, the lifting force available from excavator 172 will typically exceed the lifting force available manually via the lever arrangement discussed above. The use of machinery reduces manual work required of an operator and is more convenient in instances where a post anchor is strongly anchored in the ground. Of course, where machinery such as an excavator is not available on site, the lever arrangement illustrated in Figure 1 can be conveniently transported to the post anchor location and used to manually remove the post anchor.

[0125] The link arms 160 can comprise single plates as best shown in Figure 4 or, alternatively, can comprise dual plates 165 as best shown in Figures 12 or 13. In the case of dual plates, the plates are interwoven with each other to facilitate even load distribution. The interweaving of the dual-plate link arms is similar to the interweaving configuration of the dual-plate grippers which is best shown in Figure 13. Interweaving the link arm plates can also reduce the possibility of the plates becoming clamped, twisted or torqued under load which could cause the rotational movement to become snagged.

[0126] The invention described herein is susceptible to variations, modifications and/or additions other than those specifically described and it is to be understood that the invention includes all such variations, modifications and/or additions which fall within the spirit and scope of the present disclosure.

[0127] Throughout the description and claims of this specification the word "comprise" and variations of that word, such as "comprises" and "comprising", are not intended to exclude other additives, components, integers or steps.

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. A post anchor removal device for removing a post anchor having a tubular body with an open end, the post anchor removal device including: a rigid support which defines a fulcrum a lever which is rotatable about the fulcrum through a substantially vertical plane the lever extending on either side of the fulcrum to define a first portion on one side and a second portion on the other side, whereby downward movement of the first portion results in upward movement of the second portion the second portion being connected to a gripping arrangement for at least partial insertion into the body of a post anchor the gripping arrangement being expandable from an insertion condition in which the gripping arrangement is contracted for insertion into the open end of the tubular body, to a gripping condition in which the gripping arrangement is expanded for gripping the inside surface of the tubular body the gripping arrangement being connected to the second portion of the lever for applying a lifting load to the gripping arrangement during rotational movement of the lever, the gripping arrangement including a pair of grippers which are movable between the insertion condition and the gripping condition and each of the pair of grippers having a gripping surface arranged for frictionally engaging and gripping the inside surface of the tubular body of the post anchor, the grippers being rotatably connected to each other at a rotatable connection and being movable about the rotatable connection between the insertion condition and the gripping condition, the grippers including proximal and distal ends and the rotatable connection between the grippers being located at or adjacent the distal ends of the grippers, wherein, in use, with the gripping arrangement inserted into the tubular body of a post anchor and in the gripping condition, the gripping arrangement is operable such that the lifting load tends to drive the gripping arrangement into gripping engagement with the inside surface of the tubular body of the post anchor.

2. A device according to claim 1, the gripping arrangement including a linkage mechanism connecting the second portion of the lever to a connection point on each gripper, the connection point on each gripper being spaced from the rotatable connection of the grippers.

3. A device according to claim 2, whereby contractive movement of the respective connection points toward one another corresponds to expansive movement of the respective gripping surfaces into the expanded condition.

4. A device according to claim 3, the pair of grippers having an intersecting configuration in which the respective connection points and the respective gripping surfaces are located on either side of an intersection.

5. A device according to claim 4, the intersection is spaced from the rotatable connection of the grippers.

6. A device according to any one of claims 2 to 5, the linkage mechanism including: a drive linkage which is connected to the second portion of the lever; and a pair of link arms which are rotatably connected, at a first end, to the drive linkage and are rotatably connected, at a second end, to the respective connection points on each gripper.

7. A device according to claim 6, wherein:

the rotatable connection between the pair of link arms moves towards the rotatable connection between the grippers for contractive movement of the grippers and the rotatable connection between the pair of link arms moves away from the rotatable connection between the grippers for expansive movement of the grippers; and/or

the link arms are generally L-shaped and the connections to the drive linkage and the respective connection points on each gripper are made at opposite ends of the link arms; and/or

the drive linkage is connectable to the second portion of the lever at various points along the length of the drive linkage to facilitate adjustment of a distance between the second portion of the lever and the grippers.

8. A device according to any one of the preceding claims, the grippers having an elongate, arcuate shape and the gripping surfaces being formed toward the distal ends.

9. A device according to any one of the preceding claims, the grippers being movable relative to one another in opposite directions from the insertion condition to the gripping condition.

10. A device according to any one of the preceding claims, wherein, in the insertion condition, the grippers define a substantially oval profile, and in the gripping condition, the grippers define a substantially tear-drop profile.

11. An expandable gripping device for removing a post anchor having a tubular body with an open end, the expandable gripping device including: a pair of grippers which are movable between an insertion condition in which the grippers are contracted for insertion into the open end of the tubular body, to a gripping condition in which the grippers are expanded for gripping an inside surface of the tubular body, each of the pair of grippers having a gripping surface arranged for frictionally engaging and gripping the inside surface of the tubular body, the grippers being rotatably connected to each other at a rotatable connection and being movable about the rotatable connection between the insertion condition and the gripping condition, the grippers including proximal and distal ends and the rotatable connection between the grippers being located at or adjacent the distal ends of the grippers, wherein the grippers are connectable to a lifting arrangement for applying a lifting load to the grippers, and wherein, in use, with the grippers inserted into the tubular body of a post anchor and in the gripping condition, the grippers are operable such that the lifting load tends to drive the grippers into gripping engagement with the inside surface of the tubular body of the post anchor.

12. A device according to claim 11, the grippers having an elongate, arcuate shape and the gripping surfaces being formed toward the distal ends.

13. A device according to claim 11 or 12, each gripper including a connection point which is spaced from the rotatable connection of the grippers.

14. A device according to claim 13, whereby contractive movement of the respective connection points toward one another corresponds to expansive movement of the respective gripping surfaces into the expanded condition.

15. A device according to claim 14, the pair of grippers having an intersecting configuration in which the respective connection points and the respective gripping surfaces are located on either side of an intersection which is spaced from the rotatable connection and whereby contractive movement of the connection points toward one another corresponds to expansive movement of the gripping surfaces into the expanded condition.

16. A device according to any one of claims 13 to 15, wherein: the gripping device further includes a pair of link arms which are rotatably connected to one another at a first end and are rotatably connected, at a second end, to the respective connection points on each gripper; and/or the gripping device further includes a pair of link arms which are each rotatably connected at respective first ends to a distal end of a lifting link and are rotatably connected, at respective second ends, to the respective connection points on each gripper.

17. A device according to claim 16, the gripping device further including a coupling point for coupling the gripping device to a lifting arrangement, wherein the coupling point of the gripping device is located at a proximal end of the lifting link.

18. A device according to claim 17, the coupling point being located at the rotatable connection between the first ends of the link arms.

19. A device according to any one of claims 16 to 18, the rotatable connection between the pair of link arms moving towards the rotatable connection between the grippers for contractive movement of the grippers and the rotatable connection between the pair of link arms moving away from the rotatable connection between the grippers for expansive movement of the grippers.

20. A device according to any one of claims 11 to 19, wherein: the grippers are movable relative to one another in opposite directions from the insertion condition to the gripping condition; and/or in the insertion condition, the grippers define a substantially oval profile, and in the gripping condition, the grippers define a substantially tear-drop profile.

152 152 100 121 121 146 117 118 113 111 143 154 113 125 112 147 156 114 114 145 147 125a 158 150 150 125 111 FIGURE 2 1/8

160 160 125b 111 112

112

FIGURE 1 FIGURE 3

162 159 158 161 159

160 162 162 160 160 161 131 160 129 129

163 163 129 129 163 130 130 2/8

163 37 162 131 34 167 167 36 130 35 130 166 36 144 144 164 FIGURE 4 168 FIGURE 5

158

162 160 161 160 160 160

129 129 167 3/8

129 129 163 163

130 130 130 162 161 166 167 130 144 159

144 144 159 144 164 164 FIGURE 6 FIGURE 7

100 152 100 152

150 156 156 150

158 158

111 111 4/8

112 34

34 112

FIGURE 8 FIGURE 9