The present invention relates to post raising apparatus. More specifically the invention concerns apparatus that can be attached to a post to raise the post and assist in the removal of the post from the ground. The term "post" includes poles or like elongate members and the term "post" is used hereinafter for convenience only and is not intended to be limiting on the scope of the invention. Manually removing posts mounted in the ground by digging round the post can be difficult and time consuming where the post is buried to a considerable depth and/or the buried portion is surrounded by concrete.

The present invention aims to provide apparatus that addresses this and enables posts to be removed more easily.

According to the invention, there is provided apparatus for raising a post, the apparatus having a carriage mounted for movement between a lowered position and a raised position, and a clamp assembly mounted on the carriage and having clamping members mounted for movement towards and away from each other for gripping a post therebetween.

The carriage may be supported on a frame. The frame may be adapted for mounting the apparatus on a carrier. For example the frame may be detachably mounted on the carrier. The carrier may be a vehicle such as an excavator.

The carriage may extend between and be supported for up and down movement between the lowered position and raised position by guide members. The carriage may be raised and lowered by one or more actuators acting between the frame and the carriage. Up and down movement of the carriage may be configured to apply a pulling force in a single direction, typically a vertical or substantially vertical direction. In this way, the pulling force acts in the pulling direction and sideways forces transverse to the pulling direction that might cause the post to bend and break are largely avoided or eliminated. Because the pulling force acts in the pulling direction, all the force goes back through the ground. Because all the force goes back through the ground rather than through the carrier when removing a post the apparatus can be essentially freestanding in use with the carrier being employed as a means of transporting the apparatus.

The or each actuator may comprise a ram. The or each ram may be connected to a power source to extend/retract the ram. For example the or each ram may be powered by hydraulic or pneumatic fluid from a vehicle on which the apparatus is mounted. The or each ram may comprise a piston/cylinder unit. In other embodiments, the or each actuator may comprise a linear actuator powered by a motor.

The carriage may be attached to the guide members by one or more roller assemblies. The or each roller assembly may include at least one roller located in a channel extending lengthwise of the guide member. For example, the guide members may be of I-section and the or each roller assembly may have a pair of rollers engaging the channels on both sides of the guide members.

One or both clamping members may be mounted for sliding movement towards and away from the other clamping member to close and open the clamp assembly. Alternatively, one or both clamping members may be mounted for pivotal movement towards and away from the other clamping member to close and open the clamp assembly. The clamp assembly may be opened and closed by one or more actuators acting between the carriage and one or both clamping members.

The or each actuator may comprise a ram. The or each ram may be connected to a power source to extend/retract the ram. For example the or each ram may be powered by hydraulic or pneumatic fluid from a vehicle on which the apparatus is mounted. The or each ram may comprise a piston/cylinder unit. In other embodiments, the or each actuator may comprise a linear actuator powered by a motor.

The clamp assembly may be configured to control closing movement of the clamping members to grip a post therebetween without bending the post. For example, it may be that closing movement of a clamping member stops when it contacts the post allowing the clamp assembly to auto adjust to any position of the post between the clamping members. For example, it may be that the rams are connected to a common source of hydraulic or pneumatic fluid to actuate the rams until they encounter a resistance to closing movement of the clamp assembly such as when coming into contact with the post. In this way the apparatus does not have to be positioned so that the post is located centrally between the clamping members prior to closing the clamp assembly as the clamp assembly automatically adapts to grip a post that is offset from the centreline. Because the pulling force acts in the pulling direction and all the force goes back through the ground, the stability of the apparatus is not affected when clamping a post that is offset from the centre-line.

The apparatus may include means to assist removal of a post. For example the post may be loosened prior to or during pulling by applying a vibrational or percussive force. In some embodiments, a vibrator unit may be mounted on the carriage. The vibrator unit may be powered by a motor. The vibrator unit may be operable when the clamp assembly has been closed to grip a post.

These and other features, benefits and advantages of the invention will be more fully understood from the following description of exemplary embodiments given by way of example only with reference to the accompanying drawings wherein:-

Figure 1 is a perspective view of apparatus according to a first embodiment with the carriage lowered and the clamp assembly open;

Figure 2 is a front view of the first embodiment;

Figure 3 is a plan view of the first embodiment;

Figure 4 is a side view of the first embodiment;

Figure 5 is a perspective view of the first embodiment with the carriage raised and the clamp assembly open;

Figure 6 is a perspective view of apparatus according to a second embodiment with the carriage lowered and the clamp assembly closed;

Figure 7 is a front view of the second embodiment;

Figure 8 is a plan view of the second embodiment;

Figure 9 is a side view of the second embodiment; Figure 10 shows a modification of the first embodiment; and

Figure 11 shows another modification of the first embodiment with some parts omitted for clarity.

Referring to the accompanying drawings, apparatus according to a first embodiment is shown in Figures 1 to 5 and apparatus according to a second embodiment is shown in Figures 6 to 9. Modifications are shown in Figures 10 and 1 1. Like reference numerals are used throughout the drawings and the following description to indicate the same or similar parts. Accordingly, the description of the same or similar parts of the second embodiment is not repeated in detail and will be understood by those skilled in the art from the description of the first embodiment. Referring now to Figures 1 to 5, apparatus according to the first embodiment is shown and includes a frame 1 for attaching to a carrier for supporting the apparatus in use. Suitable carriers include, but are not limited to excavators, lorry mounted cranes (e.g. Hiab type), and tracked vehicles. The frame 1 may be modified for use of the apparatus with different carriers.

The frame 1 may be mounted on a trailer or the like for transportation to a site for use. The frame 1 may be releasably connected to the carrier so as to be attached to and detached from the carrier as required. In other embodiments (not shown), the apparatus may be self-supporting. For example the frame 1 may be provided with wheels or tracks for moving the apparatus. Where the apparatus is self-contained in this way, stabilisers may be provided for engagement with the ground in use of the apparatus. The apparatus further includes a carriage 3 supported for up and down movement on the frame 1 between a lowered position shown in Figure 1 and a raised position shown in Figure 5. The carriage 3 is provided with a clamp assembly 5 for attaching to a post (not shown) in the lowered position of the carriage 3 whereby raising the carriage 3 raises the clamp assembly 5 together with the post for removing the post from the ground.

The frame 1 includes a transverse, horizontal rear member 7 and a rearward extending mounting plate 9 for attaching the frame 1 to the carrier by means of a linkage (not shown). The frame 1 further includes forward extending horizontal side members 1 1 and upward extending vertical guide members 13 attached to the side members 1 1.

The frame 1 further includes bracing members 15 between the rear member 7 and central plate 9, bracing members 17 between the rear member 7 and side members 1 1 , and bracing members 19 between the side members 1 1 and guide members 13.

The carriage 3 is mounted on the guide members 13 for up and down movement between the lowered position shown in Figure 1 and the raised position shown in Figure 5 under the control of rams 21 acting between the frame 1 and the carriage 3.

The carriage 3 includes a transverse, horizontal support member 23 and vertical post members 25. The post members 25 are attached to the guide members 13 by upper and lower roller assemblies 27, 29.

In this embodiment the guide members 13 are of I-section and the roller assemblies 27, 29 include rollers 27a, 29a are located and retained in channels 3 1 on both sides of the I-section guide members 13. The length of the guide members 13 may be adapted to provide any desired range of pulling movement for the intended application of the apparatus to remove posts of different length. It will be understood that any other arrangement for mounting the carriage 3 for up and down movement may be employed. The rams 21 are housed in the post members 25 in the lowered position of the carriage shown in Figure 1. The rams 21 may be connected to a power source on the carrier or any other suitable power source for extending/retracting the rams 21 to raise and lower the carriage 3. The rams 21 may be operated hydraulically or pneumatically. In this embodiment the rams 21 are piston/cylinder units but any extendible rams may be employed. For example a screw ram.

The clamp assembly 5 includes clamping members 33 mounted on the support member 23 for movement towards and away from each other to close and open the clamp assembly 5 under the control of rams 35 acting between the clamping members 33 and the carriage 3.

The clamping members 33 are located on the support member 23 by slide members 37 for sliding movement between the open position shown in the Figures and a closed position (not shown). It will be understood that any other arrangement for mounting the clamping members for sliding movement towards and away from each other may be employed.

The rams 35 are housed in the clamping members 33 in the open position of the clamp assembly shown in the Figures. The rams 35 may be connected to a power source on the carrier or any other suitable power source for extending/retracting the rams 35 to close/open the clamping assembly 5. The rams 35 may be operated hydraulically or pneumatically. In this embodiment the rams 21 are piston/cylinder units but any extendible rams may be employed. For example a screw ram. In use to remove a post, the apparatus is mounted on a suitable carrier by attaching the plate 9 to the carrier via a suitable linkage. The piston/cylinder units 21 , 35 are connected to a suitable power source. Where the power source is provided by the carrier, for example hydraulic fluid, a first circuit may connect the piston/cylinder units 21 to a hydraulic fluid circuit on the carrier and a second circuit may connect the piston/cylinder units 35 to a separate hydraulic fluid circuit on the carrier. With this arrangement, operation of the piston/cylinder units 21 , 35 can be at the same or different times. Alternatively, the first and second circuits may be connected to a common hydraulic fluid circuit on the carrier with an appropriate arrangement such as a solenoid switch for controlling flow of hydraulic fluid to a selected circuit. With this arrangement, operation of the piston/cylinder units 21 , 35 can be at different times. With the carriage 3 in the lowered position shown in Figure 1 and the clamping members 33 moved apart to open the clamp assembly 5 as also shown in Figure 1 , the apparatus may be positioned to locate a post having its lower end buried in the ground between the clamping members 33. The carrier may be configured to move the apparatus between a lowered position with the side members 1 1 of the frame 1 on the ground for removing a post from the ground so that forces are transferred to the ground rather than the carrier and a raised position above the ground for moving the apparatus. Alternatively or additionally the apparatus may be provided with stabilisers that can be lowered to engage the ground when removing a post so that forces are again transferred to the ground rather than the carrier.

The clamping members 33 can then be moved towards each other to close the clamp assembly 5 by operation of rams 35 so that the clamping members 33 engage and grip the post on opposite sides. The rams 35 may be configured so that, when closing the clamp assembly 5, each clamping member 33 stops when it comes into contact the post. In this way, the position of the post between the clamping members 33 in the open position of the clamp assembly 5 is not critical and the clamp assembly 5 automatically adapts to engage and grip the post without bending or breaking the post when closing the clamp assembly 5 for any position of the post between the clamping members 33. One way this can be achieved is by connecting both rams 35 to a common source of hydraulic or pneumatic fluid so that, as the rams extend to close the clamp assembly the fluid extends both rams until one of the rams contacts the post whereupon the resistance to closing movement causes the fluid to flow along the path of lower resistance to continue to close the other ram until both rams contact and grip the post. Other ways of controlling closing movement may be employed. The carriage 3 can then be raised by operation of the rams 21 to lift the clamping members 33 and the post held therebetween to remove the post from the ground. In this way, the post is pulled from the ground in a vertical direction and the apparatus uses the ground itself in conjunction with raising the carriage to force the post from the ground. By applying a pulling force to raise the post that acts in a vertical direction only, the application of sideways forces to the post transverse to the pulling direction can be avoided and the risk of the post breaking as it is removed from the ground reduced or eliminated. Because the pulling force acts in the pulling direction and all the force goes back through the ground, the stability of the apparatus is not affected when clamping a post that is offset from the centre of the apparatus.

The post can be released by operation of the rams 35 to move the clamping members 33 away from each other to open the clamp assembly 5. The carriage 3 can be lowered by operation of the rams 21 and the apparatus positioned to remove another post by repeating the above operation.

Where the post is of long length, the post may be secured by any suitable means that prevents the post toppling over when the clamping assembly 5 is released. For example one or more chains or straps may be provided that retains the post in a vertical orientation when the clamp assembly is released. The chains or straps may allow the post to be lowered in a controlled manner.

The clamping members 33 may be provided with gripping members or j aws 39 that engage the post. The gripping members 39 may have a profile to match the post. For example, the gripping members 39 may be flat when the post is rectangular or may be curved when the post is circular. The gripping members 39 may be detachable so that the appropriate gripping members can be fitted to the clamping members 33. The gripping members 39 may be fixed or adjustable. The gripping members 39 may be attached to allow the gripping members to self-align with the post. For example the gripping members 39 may to pivot, hinge, swivel or rotate.

Referring now to Figures 6 to 9, apparatus according to a second embodiment is shown. In this embodiment, the clamping members 33 are attached to the support member 23 for pivotal movement to open and close the clamp assembly 5 under the control of the piston/cylinder units 35.

The gripping members 39 are also preferably attached to the clamping members 33 so as to self-align with the surface of the post when the clamping assembly 5 is closed to grip the post. For example the gripping members 39 may pivot, hinge, swivel or rotate. In other respects the construction and operation of this embodiment is similar to and will be understood from the description of the first embodiment. Referring now to Figure 10, a modification of the first embodiment is shown. In this modification, a device 5 1 is provided to assist removal of a post by applying a force to loosen the post prior to and/or during the pulling operation. The device 51 may comprise a vibration unit or percussive unit. The device 51 may employ any suitable motive force such as hydraulic or pneumatic fluid or a motor. In this embodiment, the device 51 is mounted on the carriage but this is not essential and the device 5 1 may be mounted in other positions. In use, actuation of the device 51 applies a vibrational or percussive force to a post held by the clamp assembly 5 that may assist in loosening the post prior to and/or during the pulling operation to remove the post from the ground. Another modification that may be employed with or without the device 51 is the provision of guards 53 for the roller assemblies 27,29. The guards 53 cover the roller assemblies 27, 29 on the outboard side of the guide members 13 but may be configured to cover the roller assemblies 27, 29 on the outboard and inboard sides of the guide members 13. In other respects the construction and operation is similar to and will be understood from the description of the first embodiment. The second embodiment may also be provided with the device 51 and/or the guards 53 for the same purpose.

Referring now to Figure 1 1 , a further modification of the first embodiment is shown. Some parts are omitted for clarity. In this modification, a single ram 35 is employed to close and open the clamping members 33. As with the first embodiment, the ram 35 may comprise a piston/cylinder unit. In use, the ram 35 extends to move the clamping members 33 apart to open the clamp assembly 5 and draws the clamping members 33 together to close the clamp assembly. The ram 35 may be configured so that, when closing the clamp assembly 5, each clamping member 33 stops when it comes into contact the post. In this way, the position of the post between the clamping members 33 in the open position of the clamp assembly 5 is not critical and the clamp assembly 5 automatically adapts to engage and grip the post without bending or breaking the post when closing the clamp assembly 5 for any position of the post between the clamping members 33. A single ram 35 may be used for both clamping members in place of the separate rams 35 in the first embodiment. In other respects the construction and operation is similar to and will be understood from the description of the first embodiment. The second embodiment may also be provided with a single ram 35 for the same purpose. Any other suitable actuator for both clamping members 33 may be employed in any embodiment.

It will be understood that the invention is not limited to the above- described embodiments and that various changes may be made within the scope of the invention.

For example, in the above-described embodiments, both clamping members 33 are movable to open and close the clamping assembly. In other embodiments, it may be that one clamping member is fixed or stationary and the other clamping member is movable relative thereto to open and close the clamp assembly.

For example, in the above-described embodiments, the carriage 3 is raised and lowered by piston/cylinder units 21 at each side. In other embodiments, it may be that a single piston/cylinder unit 21 is employed on one side to raise and lower the carriage 3. In this arrangement, it may be that the piston/cylinder unit on the other side is replaced by a guide for locating the carriage for up and down movement. For example, in the above-described embodiments, the carriage 3 is raised and lowered by a pair of piston/cylinder units 21. In other embodiments, it may be that the piston/cylinder units 21 are replaced by other means for raising and lowering the carriage. Thus it may be that the carriage is raised and lowered by an electric motor. The electric motor may operate a drive mechanism to raise and lower the carriage. The drive mechanism may comprise a rack and pinion. A rack and pinion may be provided on one side of the carriage with a guide provided for locating the carriage on the other side for up and down movement. Alternatively, a rack and pinion may be provided on both sides. Where a rack and pinion is provided on both sides, they may be operated by the same electric motor or by separate electric motors.

For example, in the above-described embodiments, the clamping members 33 may be provided with gripping members 39. It may be that the clamping members 33 and/or gripping members 39 are provided with one or more features to grip the post. For example features that provide a frictional grip such as a roughened surface and/or features that provide a mechanical grip such as one or more spikes. Where provided a gripping member 39 may be fixed or adjustable. For example a gripping member 39 may be configured to self-align with the post. For example a gripping member 39 may pivot, hinge, swivel or rotate.

For example, in the above-described embodiments, the apparatus can be mounted on a carrier for positioning the apparatus. It may be that the apparatus is adapted for use without a carrier. For example, the apparatus may be provided with wheels for moving and positioning the apparatus. The wheels may be raised to position the frame on the ground and lowered to lift the frame clear off the ground for moving the frame.

The post removing apparatus described herein may provide one or more of the following benefits and advantages: Apparatus applies a vertical pull to remove post so that no force is transmitted to the carrier and all force to remove the post is transmitted back to the ground.

Clamp assembly can clamp any profile of post.

Clamp assembly may deform ' soft' or deformable posts for enhanced grip.

Clamp assembly can auto adjust and grip post if it is offset i.e. not perfectly central on machine between the clamping members prior to closing the clamp assembly without affecting stability of the apparatus.

Clamp assembly may employ one or two rams depending on size with operation the same for both.

Apparatus can be scaled up or down in size to suit application.

Apparatus can be operated facing away or towards operator.

Apparatus can operate on uneven ground as frame is designed to flex.

Posts can be taken out in one pull operation as carriage height can be tailored to suit the application as pull is vertical.

Post is held firmly between clamping members so there is no danger of any ej ected parts as any post which breaks whilst being pulled remains held firmly in the clamp j aws.

Apparatus can be fitted to several types of carrier

Apparatus can remove concrete footings

Different shaped gripping members can be fitted (flat, semicircular, vee shaped)

Apparatus may be self-contained with wheels or tracks for moving the apparatus.

As utilized herein, the terms "approximately," "about," "substantially", and similar terms are intended to have a broad meaning in harmony with the common and accepted usage by those of ordinary skill in the art to which the subj ect matter of this disclosure pertains. It should be understood by those of skill in the art who review this disclosure that these terms are intended to allow a description of certain features described and claimed without restricting the scope of these features to the precise configuration shown. Accordingly, these terms should be interpreted as indicating that insubstantial or inconsequential modifications or alterations of the subj ect matter described and claimed are considered to be within the scope of the invention as recited in the appended claims.

It should be noted that the term "exemplary" as used herein to describe various embodiments is intended to indicate that such embodiments are possible examples, representations, and/or illustrations of possible embodiments (and such term is not intended to connote that such embodiments are necessarily extraordinary or superlative examples).

The terms "attached", "connected," "secured" and the like as used herein mean the joining of two members directly or indirectly to one another. Such joining may be stationary (e.g., permanent) or moveable (e.g., removable or releasable). Such joining may be achieved with the two members or the two members and any additional intermediate members being integrally formed as a single unitary body with one another or with the two members or the two members and any additional intermediate members being attached to one another.

References herein to the positions of elements (e.g., "above," "below," "horizontal", "vertical", "forward", "rearward" etc.) are merely used to describe the orientation of various elements in the FIGURES. It should be noted that the orientation of various elements may differ according to other exemplary embodiments, and that such variations are intended to be encompassed by the present disclosure. It is important to note that the construction and arrangement of the apparatus as shown in the various exemplary embodiments are illustrative only. Although only a few embodiments have been described in detail in this disclosure, those skilled in the art who review this disclosure will readily appreciate that many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, mounting arrangements, use of materials, colors, orientations, etc.) without materially departing from the novel teachings and advantages of the subj ect matter described herein. For example, elements shown as integrally formed may be constructed of multiple parts or elements, the position of elements may be reversed or otherwise varied, and the nature or number of discrete elements or positions may be altered or varied. The order or sequence of any process or method steps may be varied or re-sequenced according to alternative embodiments. Other substitutions, modifications, changes and omissions may also be made in the design, operating conditions and arrangement of the various exemplary embodiments without departing from the scope of the present invention.

The invention extends to and includes any feature of any of the embodiments employed separately or in combination with any other feature of the same or other embodiments. The invention also extends to and includes replacement of any feature of any of the embodiments by the corresponding feature of another embodiment performing the same or similar function or by an equivalent feature performing the same or similar function.