GB1604613A

GB1604613A - Apparatus for anchoring

Info

Publication number: GB1604613A
Application number: GB1826177A
Authority: GB
Original assignee: EARTH ANCHORS Ltd
Current assignee: EARTH ANCHORS Ltd
Priority date: 1978-05-31
Filing date: 1978-05-31
Publication date: 1981-12-09

Description

(54) APPARATUS FOR ANCHORING (71) We, EARTH ANCHORS LIMI TED, a British company, of Bell Works, Bensham Lane, Thornton Heath, Surrey CR4 7ET, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to improvements in apparatus for anchoring and is particularly concerned with providing an anchor in earth or ground. Such anchors are commonly referred to as earth anchors and are used in many and varied applications. For example, they can be used for holding wires or ropes supporting a telegraph pole, to mark a surveying point, or even to hold tunnels or other structures against displacement.

Many anchoring devices require holes to be excavated and concrete blocks to be poured in position and are expensive in labour and materials and are time consuming to install.

More simple devices have been proposed in which the anchor is in the form of rod with external inclined vanes screwed into the ground, the vanes then resisting removal of the rod from the ground. Such anchors require powerful equipment on site to effect the screwing action.

There are many applications where an anchoring device is required to withstand an applied force of several tons tending to pull it from the earth or ground in which it is anchored. One such application, for example, is in supporting telegraph poles. The material of which the anchoring elements are formed and the dimensions of the anchoring element which are driven within a hollow tube and deformed outwardly by a deflecting surface to form anchoring flukes are necessarily limited by the fact that they have to be capable of being deflected and deformed outwardly by the deflecting surface and must penetrate the surrounding earth or ground.

For any given construction of anchoring element there is a magnitude of load which when applied to withdraw the anchoring element from the ground will cause, the hollow tube to commence to move out of the ground and the anchoring flukes to deform downwardly with respect thereto. The anchoring effect then diminishes progressively and the earth anchor can be withdrawn from the ground.

It is an object of the present invention to provide an improved earth anchor which is simple and economic to manufacture and which can be readily installed on Site without requiring expensive equipment and with the minimum labour.

According to the present invention there is provided an anchoring device comprising a hollow tube having an earth penetrating end formed integrally therewith or secured thereto, a slot formed in the wall of the tube with a lower edge disposed towards the penetrating end and defined by the tube wall, a deflecting surface within the tube leading from the interior of the tube towards the lower edge of the slot, an anchoring element of deformable metal disposed within the tube and associated with the deflecting surface for displacement towards and past the deflecting surface for deflection outwardly through the slot and sup port means supported by the tube and supportingly engageable externally of the tube with the outwardly deflected anchoring element.

The invention further provides an anchoring device comprising a hollow tube having an earth penetrating end formed integrally therewith or secured thereto, a pair of slots angularly spaced about the direction of length of the tube and formed in the wall of the tube by flaps formed in the tube wall and deformed inwardly to provide deflecting surfaces leading from the interior of the tube towards the edge of the slot nearest the penetrating end, at least one anchoring element of deformable metal associated with each deflecting surface and disposed within the tube for displacement towards the associated deflecting surface and deflection outwardly through the associated slot and a support means associated with each slot and supported by the tube for supporting engagement externally of the tube with the at least one anchoring element deflected outwardly through the associated slot.

Embodiments of the invention will now be described by way of example, reference being made to the accompanying drawings in which: Fig. 1 is a fragmentary part sectional, part elevational view of an anchoring device according to the present invention, Fig. 2 is a fragmentary sectional view taken on the line II4I of Fig. 1 showing the lower or leading end of the anchoring device with parts shown in elevation, Fig. 3 is a view similar to Fig. 2 showing a part of the device intermediate its length, Fig. 4 is a top plan view of the device shown in Fig. 1, Fig. 5 is a side elevation of a ramming device for use with the anchoring device of Fig. 1, Fig. 6 is an elevational view of the ramming device shown in Fig. 5 turned through 90 , Fig. 7 is a part-sectional, partevational view of the lower end of an earth anchor according to the present invention showing on one side the anchoring element in its driven and extended position and on the other side the anchoring element in its initial starting position, Fig. 8 is a side elevational view of the earth anchor shown in Fig. 7 as seen in the direction of the arrow A, Fig. 9 is a plan view of the earth anchor shown in Fig. 7, Fig. 10 is a side elevational view of a modified form of earth anchoring showing on the left-hand side an anchoring element deflected and extended to the operative position and on the right-hand side an anchoring element in its stored or inoperative position, Fig. 11 is a plan view of a detail of Fig.

10 as seen in the direction of the arrow B, Fig. 12 is a side view of a detail of Fig.

10 as seen in the direction of the arrow C, and Figs. 13, 14 and 15 are views respectively similar to Figs. 10, 11 and 12 illustrating a modification.

The anchoring device of the example shown in Figs. 1 to 4 comprises a rectangular section tube 1 of appropriate length for the application in view. In this example, the tube is of square section and formed of rolled steel being 50 mm external side and 4 mm wall thickness.

At its lower end, the tube is cut along its corners to form end pieces 2 which are shaped to triangular configuration and bent inwards to form a pyramid and welded at the apex 3 to form a penetrating end. As an alternative, the tube 1 can have a penetrating end secured thereto.

Towards the penetrating end, the tube is cut along lines 4 in two opposed walls to form flaps 5 which are bent inwards along line 6 to form a slot 7 and provide opposed deflecting surfaces 8 leading to the lower edge of the slot 7. These flaps 5 may be welded together as at 9 but this is not essential as, in use, the flaps 5 are urged towards each other to provide mutual support. Within the tube 1 are disposed two similar sets or groups of anchoring elements of a deformable or malleable metal, one set being associated with one deflecting surface 8 and the other set being associated with the other deflecting surface 8.

Each group or set comprises three anchoring elements 10, 11 and 12 which are of different lengths considered in the direction of length of the tube 1. The anchoring elements have a width approaching that of the interior of the tube 1 and a thickness approximating to onesixth of the interior side of the tube so that when the two sets of anchoring elements are mounted in the tube 1 they are constrained against any substantial movement in directions normal to their direction of length. The anchoring elements are in the form of narrow elongate rectangular plates and their leading ends are chamfered to provide a penetrating edge, the chamfering on the outermost element 12 being reversed with respect to that of the other two elements 10 and 11. The leading ends of the anchoring elements 10 and 11 are radiused to a small extent to facilitate the commencement of deformation.For example, the inner anchoring element 10 is radiused for 14 inches and the intermediate anchoring element is radiused for 1+ inches from its leading end to a radius of 3 inches. The leading edges of the anchoring elements 10 and 11 lie adjacent the inner plane of the slot 7, the leading end of the element 11 being above that of the element 10. The leading end of the outer element 12 is not radiused and lies above the leading end of the intermediate element 11 and just behind the upper edge of the slot 7.

As can be seen in Fig. 3, the inner anchoring elements 10 have the shortest length, the intermediate elements 11 have an intermediate length and the outer elements 12 have the longest length. By way of example, the inner elements 10 may have a length of 6 inches, the intermediate elements 11 a length of 7k- inches, and the outer elements 12 a length of 10+ inches.

A ramrod 13 (Figs. 5 and 6) is provided for use with the anchoring device described and comprises a rod which at its upper end 14 is dimensioned to be received as a loose fit in the tube 1, i.e., it is of square cross-section, and at its lower or leading end 15 is reduced to a thickness which is greater than that of an anchoring element 10 but less than twice the thickness of such anchoring element so that it can extend between the intermediate anchoring element 11 and abut the upper ends of the inner anchoring elements 10 and apply a driving force thereto. The length of this leading end 15 of the anchoring element 13 corresponds the distance between the upper ends of the anchoring elements 10 and 11 when positioned ready for driving as shown in Fig.

3. Intermediate the upper and lower ends 14 and 15 of the ramrod 13 is an intermediate portion 16 which is of reduced thickness with respect to the upper end 14 but of greater thickness than the lower end 15, this thickness being such that the intermediate portion 16 can be received between the outer anchoring elements 12 to engage and drive the intermediate elements 11. The length of the intermediate portion 16 is greater by a predetermined amount than the distance betweeen the upper ends of the outer anchoring elements 12 and the inner anchoring elements 10 when positioned ready for driving as shown in Fig.

3. This greater length of the intermediate portion 16 is the distance by which the inner and intermediate elements 10 and 11 can be driven by the ramrod 13 before the upper end 14 of the ramrod engages the outer elements 12. By way of example, when the anchoring elements are in the position shown in Fig. 3, the distance between the upper ends of the anchoring elements 10 and 11 can be 50 mm and the distance between the upper ends of the elements 11 and 12 can be 95 mm.

The length of the lower end 15 of the ramrod 13 is 50 mm., and the length of the intermediate portion 16 is 165 mm., so that the elements 10 and 11 can be advanced through 70 mm., before the upper end 14 of the ramrod engages the elements 12.

In order to produce an anchor, the tube 1 with the two groups of anchoring elements 10, 11 and 12 in position as shown in Fig.

3 is driven into the ground the appropriate distance. The ramrod 13 is then inserted into the tube 1 with its leading end 15 extending between the intermediate anchoring elements 11 to abut the inner elements 10 and its intermediate portion between the outer anchoring elements 12 and abutting the elements 11.

The ramrod 13 is then driven by hammer blows or the like to drive both the inner and intermediate anchoring elements 10 and 11 of each group through a predetermined distance.

The effect of this is that the inner anchoring elements, being constrained between the deflecting surface 8 and the adjacent element 11 are deformed and deflected outwardly, these deformations being substantially continuous as the elements emerge from the slot 7 so that they substantially follow the path of an arc of a circle as they are driven into the surround ing ground as shown in dotted lines in Fig.

2. The intermediate elements being constrained between the inner elements 10 and the outer elements 12 follow a similar arc, the inner elements 10 effectively providing the deflecting surface for the elements 11. After the elements 10 and 11 have been driven a predetermined distance, the ramrod 13 is removed and re versed so that its upper and larger end 14 now engages the outer elements 12 and is used to drive these elements 12 out through the slots 7. The outer elements 12 as they emerge from the slots 7 are confined between the upper edge of the slots 7 and a deflecting surface provided by the intermediate elements 11 and are similarly deformed to follow a path conforming to the arc of a circle as shown in dotted lines in Fig. 2.After the outer ele ments have been driven a predetermined dis tance, the end 14 of the ramrod 13 engages the upper ends of the intermediate elements 11 and these are driven further and beyond the elements 10, the outer elements being driven the greatest distance as can be seen in Fig. 2.

It will be noted that the anchoring flukes are formed in situ by driving the anchoring elements past the deflecting surfaces thereby to deform the anchoring elements as they are driven into the surrounding ground. With such a device, the anchoring elements do not project externally of the tube 1 when the latter is driven into the ground and so do not impede such operation. Also, it will be noted that in the example described, not more than four anchoring elements are driven at any one time so that less force is required than if all six were driven simultaneously. It will be appreciated however that only two anchoring elements can be driven simul taneously if desired, such two elements being corresponding elements in each group or set.

In the example described, anchoring flukes 10a, 11a and 12a shown in dotted lines in Fig. 2 are in groups of three with the flukes 12a driven a greater distance than the flukes 1 la and the flukes 1 Ia driven a greater distance than the flukes 1ova. Progressive support against deformation is provided by the flukes 10a to the flukes 1 la and by the flukes 1 Ia to the flukes 12a. Such an anchor can sustain a withdrawal force of several tons before the flukes are deformed sufficiently for the anchor to be drawn out of the ground and yet is quite easy to install.

In the example described, the lower ends of the anchor elements 10 and 11 are radiused and the deflecting surfaces 8 are inclined to the direction of length of the tube 1 to facilitate the deformation and deflection of the anchoring elements through the slots 7. This is not strictly necessary as it is sufficient if only the anchoring elements are radiused or inclined at these loading ends or the deflecting surface is inclined as described. The main requirement is that there should be some relative inclination between the deflecting surface and its associated anchoring element to start the deformation of the anchoring element as it is driven to emerge through the associated slot as, once started, such deformation will continue as the anchoring element is driven further.It is even possible to make the deflecting surface extend normal to the direction of length of the tube 1 provided the leading end of the associated anchoring element is bent or radiused to start it through the associated slot.

The earth anchor illustrated in Figs. 7, 8 and 9 comprises a rectangular hollow tube 101 having a lower or leading end 102 of wedge shape to facilitate driving the tube into the ground. Rectangular apertures 103 are formed in two opposed walls of the tube 101 by cutting flaps 104 in the walls and deforming the flaps inwardly to abut at their upper edges, i.e., the edges remote from the leading end 102 to provide a mutual support. The flaps 104 provide deflecting surfaces for deformable anchoring element 105 disposed slidably in the tube 101 such that when the anchoring elements are driven downwardly in the tube 101, the anchoring elements 105 are deformed by the deflecting surfaces and emerge through the apertures 103.In this example, one anchoring element 105 is associated with each flap 104 and aperture 103 and each has its leading end shaped to engage the associated flap 104 for deflection outwardly through the associated aperture. The upper or trailing ends of the anchoring elements 105 are welded together to unite them so that they may be simultaneously driven by a ramrod and to provide a spacer therebetween so t lat their leading ends are similarly spaced to engage and be deflected by the deflecting surfaces or flaps 104.

With the arrangement so far described, the driving downwards of the anchoring elements 105 in the tube 101 results in their being dec flected outwardly through the apertures 103 along a path corresponding to that shown in the left-hand side of Fig. 7. When a load is applied to remove the installed anchor, the tube 101 tends to move upwardly and the deflected anchoring element to bend about the lower end of the associated aperture 103. In order to support the deflected and extended anchoring element, supporting webs 106 are provided on the tube 101 one associated with each of the anchoring elements 105. Each web 106 is of substantially triangular shape and of relatively small thickness so as not to impede the driving of the tube 101 into the ground to any significant extent.The upper edge 107 of each web 106 is disposed below and in proximity to the path which the deflected anchoring element 105 will follow so as to afford support to such deflected anchoring element 105 at a location spaced from the tube 101. The upper edges 107 of the webs 106 may be shaped to support the deflected anchoring element 105 for the major part of the length of the edges 107 or only at a location remote from the tube 101 as shown in Fig. 7. The edges 107 may also be arranged to contribute to the deflection of the driven anchoring elements but this is not necessary.

The webs 106 are located between the apertures 103 and the leading end 102 of the tube 101 and in this example are welded to those faces of the tube 101 in which the apertures 103 are formed. As an alternative, the two webs 106 could be formed as a single Init or plate which extends through opposed slots in these faces.

It will be appreciated that even if the webs 106 do not engage the deflected anchoring elements 105 in the initially installed condition of the earth anchor, any attempt to withdraw the tube 101 from the ground brings the webs 106 into supporting engagement with the associated anchoring elements 105 and prevents any tendency of the anchoring elements to bend about the lower edges of the slots 103. Also, the moment of any load applied to the anchoring elements by the surrounding ground when a withdrawal load is applied to the tube 101 is materially reduced by the support afforded bv the webs to the anchoring elements at a location spaced from the tube 101.

It is within the scope of the present invention to provide pivotal supports for the anchoring elements which are displaced with and by the anchoring elements when they are driven out of the tube through the apertures.

Such pivotal supports may be alternative to the webs 106 described above or in addition to such webs. One such arrangement is illustrated in Figs. 10, 11, and 12 in which the same reference numerals are used to denote like parts. In this example, the anchoring elements 105 are initially driven a short distance so that their leading ends are deflected for a short distance out of the associated aperture 103 to expose a slot 108 formed in the leading end thereof. A separate pivotal support 109 is associated with each anchoring element 105 and is pivoted to the tube 101 by a bolt 110 which passes through the two walls of the tube 101 which do not have the apertures 103 and which is located at a level between the apertures 103 and the leading end 102 of the tube 101 and, in this example, just above the upper edges 107 of the webs 106.Each pivotal support has a hook-shaped free end 111 which extends through the slot 108 in the associated anchoring element 105. Each pivotal support 109 has a lower bearing edge 112 arranged to engage and be supported by the upper edge 107 of the associated web 106 when extended in the installed position and an upper rectilinear edge 113 arranged to lie against the tube 101 in its initial position before installation. Each pivotal support 109 has a further rectilinear upper bearing edge 114 arranged to bear against the under-surface of the associated anchoring element 105 in the installed and extended position. The tail 115 of each pivotal support extends through a slot 116 in the opposed walls of the tube 101 and slots 117 are formed in these opposed walls to extend downwardly from the associated aperture 103 for a distance sufficient to allow a part of the hook-shaped free end 111 to extend into the tube 101 in the initial position of the supporting element 109. The tube 101 is reinforced in the vicinity of the apertures 103 and slots 117 by longitudinal reinforcing webs 118 which are welded to the tube 101. In this example, four such reinforc ing webs 118 are provided welded to the corners of the tube 101.

The thickness of the support webs 106, pivotal supports 109 and the reinforcing webs 118 is sufficiently small not to significantly impede the driving of the tube 101 into the ground. Once the tube 101 has been driven into the ground, the anchoring elements are driven within the tube 101 by suitable means, e.g., a ramrod and the anchoring elements are driven out through the associated aperture 103 whilst being deflected and deformed by the deflecting surfaces 104 to assume the con figuration shown. At the same time, the pivotal supports 109 are pivoted outwardly, by the engagement of the hook-shaped ends in the slots 108 until, in the end position, the bearing edge 114 is brought into supporting engagement with the under face of the associated anchoring element 105 and the bearing edge 112 is brought into supporting engagement with the upper edge 107 of the associated web 106.In this installed position, each anchoring element is supported towards its extremity by the bearing edge 114 and at its inner end by the lower edge of the aperture 103. Also, each pivotal support 109 is sup ported at its tail 115 by the bearing edges 112 and 107 so that there is effectively a three point support for each anchoring element 105.

It will be appreciated that the general plane of the pivotal supports 109 is substantially the same as that of the webs 106 to ensure engagement of the bearing edges 112 and 117.

It will also be appreciated that the length of the slots 108 in the direction of length of the anchoring elements in which they are formed is sufficient to accommodate relative movement of the hook-shaped end 108 engaged therein resulting from the differences in the paths followed by the hook-shaped end 108 and the extremity of the anchoring element 105 in which it is engaged. It can be seen from Fig. 11 that the length of the anchoring element between the outermost end of the slot 108 to the free end of the anchoring element is less than the distance between opposed edges 119 and 120 of the hook-shaped free end 111 of the pivotal support 109 so as to be received between these opposed walls 119 and 120 in the installed position.

As mentioned above, in some applications of the earth anchor according to the present invention, the pivotal supports 109 may provide sufficient support in the absence of the webs 106 which could be omitted. In such a case, the tails 115 of the pivotal supports 109 would have abutments extending in a direction normal to the general plane thereof and located so as, in the extended installed position, to bear against that face of the tube 101 from which they extend, or alternatively, such abutments on the tails 115 of the two pivotal supports 109 would be located to en gage each other in the extended installed position of the supporting elements 109 so that the opposed supporting elements 109 afford a mutual support one to the other.

In order to increase the support afforded by an earth anchor according to the present invention and to enhance its resistance to any load applied tending to withdraw it from its installed condition, the surface area of the anchoring elements 105 may be increased by means of plates carried thereby. One such arrangement is shown in Figs. 13, 14 and 15 which is similar in most respects to that illustrated in Figs. 10, 11 and 12 and like references are used to denote like parts. In this arrangement, a separate plate 121 is associated with each anchoring element 105 and, in the uninstalled condition of the earth anchor is disposed to lie along the outside of that face of the tube 101 formed with the aperture 103 associated with the associated anchoring element 105.The plates 121 may be retained in this position by a temporary binding (not shown) of wire or the like and may, as shown, be formed towards their upper ends with guide tongues 122 punched out of the plate and engaging the faces of the tube 101 which are not formed with apertures 103. The lower end of each plate 121 is folded over as at 123 to receive the free end of the associated anchoring element 105. The plates are further formed with a slot 124 towards their free end which slot is similar to the slot 108 and through which the hook-shaped end 111 of the associated anchoring element passes.The plates 121 have a width greater than that of the anchoring elements and greater than that of the tube faces in order effectively to increase the surface area presented to the ground in the installed condition and materially to improve resistance to withdrawal of the earth anchor from the ground when installed. When the tube 101 is initially driven into the ground, the plates 121 offer little impediment and are to some extent shielded by the reinforcing webs 118. They then lie between the faces of the tube 101 and the surrounding ground.

When the anchoring elements 105 are driven to the extended position, the plates 121, being engaged with the free ends thereof slide down the tube and follow the anchoring element to the extended position, being constrained by the surrounding ground to follow the path of the associated anchoring element to the extended position in which they are supported by the associated anchoring element. The leading end of the plates 121 may be tapered as at 125 to facilitate their passage through the ground when the anchoring elements are being driven.

It will be appreciated that the thickness of the plates 121 which are preferably of metal is selected in relationship to the deformability of the metal such as to enable the plates 121 to be deformed and follow the anchoring elements 105 when the latter are driven to the extended and installed condition. The use of an earth anchor with plates 121 is of par ticular application where the anchor is to be installed in weak soils. The plates 121 are conveniently thin flexible steel plates and their transverse strength is materially enhanced by the curvature imparted to them when in the installed position.

It will also be appreciated that the earth anchor is not necessarily installed with the tube 101 in a vertical position and that, in some applications, it may be desirable to in stall it at an angle to the vertical.

The earth anchors described above by way of example have two anchoring elements 105 which are driven out through opposed slots 103. In some applications, one such anchoring element and associated slot may be sufficient and in others, more than two anchoring ele ments may be required in which case the anchoring elements would be arranged to be deflected by associated deflecting surfaces through associated slots angularly spaced about the axis or direction of length of the tube 101.

Also, the tube 101 is not necessarily of rec tangular cross-section but can, for example, also be of circular cross-section. In the latter case, the tube 101 may be provided with ex ternal vanes or a helix whereby it may be screwed into the ground, such vanes or helix further increasing the resistance of the in stalled earth anchor to any forces tending to remove it from the ground.

WHAT WE CLAIM IS: 1. An anchoring device comprising a hollow tube having an earth penetrating end formed integrally therewith or secured thereto, a slot formed in the wall of the tube with a lower edge disposed towards the penetrating end and defined by the tube wall, a deflecting surface within the tube leading from the interior of the tube towards the lower edge of the slot, an anchoring element of deformable metal disposed within the tube and associated with the deflecting surface for displacement towards and past the deflecting surface for deflection outwardly through the slot and support means supported by the tube and supportingly en gageable externally of the tube with the outwardly deflected anchoring element.

2. An anchoring device according to Claim 1 in which the support means is provided by a web mounted on the tube and towards which the anchoring element is deflected so that the underside of the deflected anchoring element is supported on the web.

3. An anchoring element according to Claim 2 in which the web provides a further deflecting surface for the anchoring element.

4. An anchoring device according to Claim 1 in which the support means is connected to the anchoring element for displacemen therewith when the latter is displaced through the slot.

5. An anchoring device according to Claim 4 in which the support means has an abutment operable to bear against the tube limit displacement of the support means and provide support for the anchoring element.

6. An anchoring device according to Claim 4 in which the support means has a bearing surface operable to bear against a support member associated with the tube to limit displacement of the support means and provide support for the anchoring element.

7. An anchoring device according to Claim 6 in which the support member is a web mounted on the tube.

8. An anchoring device according to any one of the preceding claims in which the anchoring element is attached to a bearing plate displaceable with and by the anchoring element to increase the surface area presented by the outwardly deflected anchoring element which increased surface area is operable to oppose withdawal of the installed anchoring device.

9. An anchoring device according to Claim 8 in which the bearing plate is mounted externally of the tube for longitudinal movement relative thereto and extends from the region of the slot, where it engages the anchoring element upwardly away from the penetrating end.

10. An anchoring device according to Claim 1 in which the anchoring element is the first of a set of anchoring elements of deformable metal disposed within the tube and associated with the deflecting surface for displacement towards and past the deflecting surface for deflection outwardly through the slot and a second anchoring element of the set is disposed between the first anchoring element and the deflecting surface to provide the support means for the first anchoring element.

11. An anchoring device according to Claim 10 in which the tube is of rectangular cross- section, a pair of opposed slots is formed in the wall of the tube, a separate deflecting surface leads from the interior of the tube towards the edge of each slot nearest the penetrating end, and a separate set of anchoring elements is associated with each deflecting surface.

12. An anchoring device according to Claim 11 in which the sets of anchoring elements are a relatively close fit in the tube to provide constraint against displacement in the direction normal to the length of the tube.

13. An anchoring device according to any one of the preceding claims in which the slot is formed by a flap formed in the wall of the tube and deformed inwardly to provide the deflecting surface which leads from the interior of the tube to the lower edge of the slot.

14. An anchoring device comprising a hollow tube having an earth penetrating end formed integrally therewith or secured thereto, a pair of slots angularly spaced about the direction of length of the tube and formed in the wall

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. an earth anchor with plates 121 is of par ticular application where the anchor is to be installed in weak soils. The plates 121 are conveniently thin flexible steel plates and their transverse strength is materially enhanced by the curvature imparted to them when in the installed position. It will also be appreciated that the earth anchor is not necessarily installed with the tube 101 in a vertical position and that, in some applications, it may be desirable to in stall it at an angle to the vertical. The earth anchors described above by way of example have two anchoring elements 105 which are driven out through opposed slots 103. In some applications, one such anchoring element and associated slot may be sufficient and in others, more than two anchoring ele ments may be required in which case the anchoring elements would be arranged to be deflected by associated deflecting surfaces through associated slots angularly spaced about the axis or direction of length of the tube 101. Also, the tube 101 is not necessarily of rec tangular cross-section but can, for example, also be of circular cross-section. In the latter case, the tube 101 may be provided with ex ternal vanes or a helix whereby it may be screwed into the ground, such vanes or helix further increasing the resistance of the in stalled earth anchor to any forces tending to remove it from the ground. WHAT WE CLAIM IS:

1. An anchoring device comprising a hollow tube having an earth penetrating end formed integrally therewith or secured thereto, a slot formed in the wall of the tube with a lower edge disposed towards the penetrating end and defined by the tube wall, a deflecting surface within the tube leading from the interior of the tube towards the lower edge of the slot, an anchoring element of deformable metal disposed within the tube and associated with the deflecting surface for displacement towards and past the deflecting surface for deflection outwardly through the slot and support means supported by the tube and supportingly en gageable externally of the tube with the outwardly deflected anchoring element.

of the tube by flaps formed in the tube wall and deformed inwardly to provide deflecting surfaces leading from the interior of the tube towards the edge of the slot nearest the penetrating end, at least one anchoring element of deformable metal associated with each deflecting surface and disposed within the tube for displacement towards the associated deflecting surface and deflection outwardly through the associated slot and a support means associated with each slot and supported by the tube for supporting engagement externally of the tube with the at least one anchoring element deflected outwardly through the associated slot.

15. An anchoring device according to Claim 14 in which each support means is provided by a web mounted on the tube and towards which the associated anchoring element is deflected so that the underside of the deflected anchoring element is supported by the web.

16. An anchoring device according to Claim 15 in which each web provides a further deflecting surface for the associated anchoring element.

17. An anchoring device according to Claim 15 or 16 in which the webs for the anchoring elements deflected outwardly through the op posed slots are provided by a single plate which extends through further opposed slots in the wall of the tube.

18. An anchoring device according to any one of Claims 14 to 17 in which each support means is connected to the associated anchoring element for displacement therewith when the associated anchoring element is displaced through the associated slot.

19. An anchoring device according to Claim 18 in which each support means has an abutment operable to bear against the tube to limit displacement of the support means and provide support for the associated anchoring element.

20. An anchoring device according to Claim 18 in which each support means has a bearing surface operable to bear against a support member associated with the tube to limit displacement of the support means and provide support for the associated anchoring element.

21. An anchoring device according to Claim 20 in which the support member comprises a separate web associated with each support means and mounted on the tube.

22. An anchoring device according to any one of Claims 14 to 21 in which each anchoring plate is attached to a bearing plate displaceable with and by the associated attached anchoring element to increase the surface area of the associated outwardly deflected anchoring element which increased surface area is operable to oppose withdrawal of the installed anchoring device.

23. An anchoring device according to Claim 22 in which each bearing plate is mounted externally of the tube for longitudinal movement relative thereto and extends from the region of the slot through which the associated anchoring element is displaceable, where it engages the associated anchoring element, upwardly away from the penetrating end.

24. An anchoring device constructed, arranged and adapted to operate substantially as herein described with reference to Figs. 1 to 4, Figs. 7 to 9, Figs. 10 to 12 or Figs. 13 to 15 of the accompanying drawings.