GB2217163A - Extractor for buried stumps and the like - Google Patents

Abstract

An extractor devised to assist the removal of such objects as buried tree stumps from the ground comprises an open base frame 5 and an upper frame 6 spaced above and supported by the base frame. A socket 8 is supported in a generally central position by the upper frame and an elongated threaded bolt means 12 extends freely and generally vertically through the socket. A collar 10 which engages the threads of the bolt means encircles the bolt means above the socket and means are provided to rotate the collar and the bolt means separately. <IMAGE>

Description

Extractor for Buried Stumps and the like.

The e present invention is an extractor to effect or assist the removal of such objects as buried tree sturps from the ground.

The need to remove such buried objects arises in various circumstances. For example, when trees have been felled because they are dead and/or unsafe, or when the trunk of a tree has been broken in a storm, the remaining stump may be held firmly in the ground by a network of roots. When a line of fencing is to be removed or replaced, the deeply-buried posts, or the lower ends of broken or cut posts, may be difficult to remove.

The usual practice is to dig deeply around the stump or post, severing roots where necessary, until the object is dislodged.

However such extensive digging is time-consumlng, may be impracticable in same restricted locations, and frequently still proves insufficient to permit removal of the buried object.

It is an object of the present invention to provide an extractor, by means of which the removal of buried objects such as tree stumps or the like from the ground may be effected or at least rendered less difficult.

The extractor according to the invention comprises an open base frame for placing on the ground, an upper frame spaced above and supported by said base frame, a socket supported by said upper frame generally centrally with respect to said upper frame, an elongated threaded bolt means extending freely and generally vertically through said socket, a collar engaging the threads of and encircling said bolt means above said socket, means to rotate said collar and separate means to rotate said bolt.

Use of the extractor according to the invention to lift, say, a buried post may readily be understood and is since in practice. The base frame and upper frame are placed on the ground above and surrounding the buried post. The elongated bolt is rotated to advance the bolt downwardly until the bolt, or a tool itounted upon it, engages the post. The collar is then rotated to withdraw the bolt upwardly and thereby to lift the post from the ground. Variations on this simple practice are described in detail hereinafter.

The base frame may be square, rectangular or circular in plan or may be of any other shape, although. it preferably forms a closed, generally symmetrical figure in plan view. For simplicity of construction and convenience in use, the base frame is preferably square or rectangular. The frame is open sufficiently to permit passage of the bolt or tool and at least an upper part of the buried object therethrough. Thus the base frame may be constructed of lengths of angle iron secured together at the corners, for example by means of bolts or by welding.

The upper frame may be formed in a similar manner to the base frame but since it is required to support at its centre the socket which is the central point of the lifting force it is preferably of somewhat stronger construction than the base frame. For example, if the base frame is of angle iron, the upper frame may be formed from lengths of box section. Preferably the outline shape of the upper frame corresponds at least substantially to the base frame in plan.

The upper frame is spaced above and supported by the base frame. Thus the main structure of the extractor may take the form of a rigid unit comprising the base frame, the upper frame and a suitable number of upright spacers, these various parts being bolted or welded together, for example. However it is preferred that this structure be designed to be assembled in situ and then dismantled for transport to another site of use. Thus in a preferred form the extractor comprises a base frame, an upper frame generally corresponding to the base frame in outline plan, and a number of spacers, adapted to engage at their opposite ends the base frame and upper frame respectively and to hold those frames in rigid, spaced relationship.

the the structure is designed to be reversibly assembled as aforesaid, either or both of the base frame and upper frame may be adapted, for example by hinging, to open horizontally to allcw them to be placed around a stump or other object having a dimension which prevents the frame being dropped into place from the top of the object. For example, if an upper part of a tree stump is wider than the open area of the base frame, then the latter could be opened in this way to allow it to be placed into position from the side of the stump.

In the region of the centre of the upper frame, a socket is supported, through which the threaded bolt means freely extends. The socket may conveniently be circular and may be supported by two or morse, preferably four, radial arms extending from the socket to the sides of the upper frame.

The bolt means has an elongated threaded portion and may be modified at its lower end to enable it to penetrate the buried object or may at that end have a chuck means or otherwise be adapted to receive interchangeably two or more different tools.

For example, the bolt may be tapered at its lower end in the form of a large wood screw or auger, to enable -it to cut into a wooden buried object and either interengage with the object or simply form a bored hole in it. The bolt may then be interchangeable with, say, a parallel-sided threaded bolt which could grip the hole from within. Alternatively, a chuck-headed or similarly adapted bolt may be provided with interchangeable bits for performing the different penetrating and gripping functions.

The upper end of the elongated bolt means may have a cross-handle formed integral with or secured to it, to enable the bolt to be rotated, or may be modified to allow a handle to be removably or irremovably attached. For example, the bolt may have a bore passing radially through it in the region of its upper end, to re receive a bar with which to rotate the bolt, or the end of the bolt may be modified to a square or other cross-section, to enable a handle to be fitted over that end.

The collar encircles the bolt means above the socket and engages the threads of the bolt means. Like the other parts of the extractor, the collar should be made of a substantial design since it is engagement of the collar with the bolt means that effects withdrawal and lifting of the buried object.

Preferably the collar has a circular shoulder at its lower face, to engage a corresponding shoulder or projection on the upper face of the socket and thereby keep the collar and the bolt means centralised within the upper frame.

Means are provided to rotate the collar. For example, the collar may be provided with radial arms for this purpose or may be shaped to engage a suitable spanner.

The invention will now be further described with reference to the accompanying drawings, wherein: Fig. 1 illustrates in vertical cross section one preferred embcdintnt of the extractor according to the present invention; Fig. 2 illustrates, in exploded perspective view, the structural fraimswork of the extractor of Fig. 1; Fig. 3 illustrates in elevation a coach bolt which may be interchanged with the bolt means of the excavator of Figs. 1 and 2; and Fig. 4 shows a lifting tool which may be used in a modified form of the excavator of Figs. 1 and 2.

The illustrated extractor comprises a square base frame 5 formed of angle iron and a corresponding upper frame 6 formed of lengths of box section, the two frames being held in mutual register above each other by four box-section spacers 7 (only three of which are visible in Fig. 2). A tubular socket 8 is held centrally on the upper frame 6 by four radial arms 9. An internally-threaded circular collar 10 rests upon the socket 8 and these two components are held in iraitual axial alignment by an annular shoulder 11 on the collar 10. TwD aligned operating arms 16 extend radially outwardly from the collar 10.

An extertelly-threaded bolt member 12, in threaded engagement with the collar 10, extends through the socket 8. The lower end of the bolt member 12 is tapered to a form resembling a large wood screw 13, while the upper end of the bolt member 12 is formed to a square cross-section at 14 so as to be able to receive an operating handle 15.

As shown in Fig. 2, the extractor can readily be dismantled for transport from place to place. When it is to be used for lifting a stubborn stump, for example, the extractor is assembled in situ upon the ground with the bolt member 12 aligned with the stump. By means of the handle 15, the bolt meeber 12 is rotated and advances downwardly through the collar 10, with the result that the screw 13 approaches the stump and penetrates it. When the screw has entered the stump to a sufficient extent to give it a firm grip upon the stump, then the collar 10 is turned in a like rotational direction (clockwise as illustrated) by means of the operating arms 16, thus retracting the bolt member and screw upwardly ard withdrawing the stump from the ground.

If the w03d of the wooden object to be lifted has deteriorated to such an extent that the screw 13 cannot gain sufficient grip to withdraw the object, then, after the screw 13 has cut into the object, the bolt member 12 may be replaced by the coach bolt 17 of Fig. 3. The bolt 17 may then be driven, by means of the handle 15, into the hole cut by the screw 13 until a good grip on the object is achieved, sufficient to allow that object to be lifted by the bolt 17 using the collar 10.

In one form of the invention, the screw 13 may be separable from the threaded upper portion of the bolt 12, to enable the screw to be replaced by another tool such as a coach bolt or the tool illustrated in Fig. 4. The appropriate tool may be held in a chuck in the lower end of the bolt member or may be screwed into a threaded bore in the bolt member and held there against rotation by a suitable pin.

The tool 18 of Fig. 4 has two pivoted arms 19 which normally adopt the positions illustrated but which may be tipped upwardly into alignment with the shaft of the tool. With the arms in the latter positions, the tool 18 may be driven into a bore in, say, a piece of buried concrete. When the arms are allowed to drop under gravity into the positions shown, their tips grip the face of the bore and allow the object to be lifted. Alternatively, the tool may be driven through to the lower side of the object, where the arms may then open fully to engage its lower face.

As stated above, the bolt 12 may be interchana-6 with other bolts modified at their lower end or may be provided with a chuck to receive a replacement tool. One such modification which is of wide utility comprises a closed ring, to which other means of attachement may be. fitted, for example by means of an eye-bolt.

For example a rope, cable or chain may be linked to the ring or a net may be attached to it, within which, for example, a shrub may be held for lifting from the ground or for planting.

Claims (11)

1. An extractor for buried stumps and the like, which comprises an open base frame for placing on the ground, an upper frame spaced above and supported by said base frame, a socket supported by said upper frame generally centrally with respect to said upper frame, an elongated threaded bolt means extending freely and generally vertically through said socket, a collar engaging the threads of and encircling said bolt means above said socket, means to rotate said collar and separate means to rotate said bolt means.

2. An extractor as claimed in claim 1, wherein the base frame forms a closed, generally symmetrical figure in plan view.

3. An extractor as claimed in claim 1 or claim 2, wherein the outline shape of the upper frame corresponds at least substantially to the base frame in plan.

4. An extractor as claimed in claim 3, including a number of rigid spacers, adapted to engage at their opposite ends the base frame and upper frame respectively.

5. An extractor as claimed in any of the preceding claims, wherein the socket is supported by two or more radial arms extending from the socket to the sides of the upper frame.

6. An extractor as claimed in any of the preceding claims, wherein the bolt means is tapered at its lover end to form a screw or auger.

7. An extractor as claimed in any of claims 1 to 5, wherein the bolt means carries a chuck at its lower end.

8. An extractor as claimed in any of the preceding claims, wfierein the bolt means is modified to allow a handle to be removably or irreluvably attached to it.

9. An extractor as claimed in any of the preceding claims, wherein the collar has a circular shoulder at its lower face, to engage a corresponding shoulder or projection on the upper face of the socket.

10. An extractor as claimed in any of the preceding claims, wherein the collar is provided with radial arums.

11. An extractor for buried stumps and the like, which is substantially as hereinbefore described with reference to, and as illustrated in, the accompanying drawings.