THEREFOR

TECHNICAL FIELD OF THE INVENTION The present invention relates to ground anchors.

In particular, though not solely, the present invention is directed to ground anchors that can be driven into the ground and then set to allow a load to be anchored. BACKGROUND OF THE INVENTION

In certain instances, there is a need to anchor an item relative to the ground and to take a load from the item and pass it into the ground. For example, guy lines for a power or telecommunications pole, or for a tensioned structure such as the support structure or assembly for agriculture, such as vines or similar. Such anchors may also be used as ground anchors for slope stabilisation also.

One such method is a penetrative fastening that is pushed into the soil. Some initial systems were similar to a tent peg and pushed into the ground at an angle to the required load, for example at approximately 90 degrees to the direction of load.

Improvements to this were in-ground anchors that were driven into the ground in the direction of loading, there being an anchor plate or similar at the end of the anchor that would engage the ground and resist the anchor movement in the direction of loading. As such these types of anchors are typically considered permanent, since removing them would require digging then out of the ground.

The first such ground anchor systems were for non-rocky soil only. These would have an anchor plate on one end of a tether. The tether could be a rigid rod, or a flexible tether. The anchor plate end, connected to the tether, was driven into the soil in the direction and angle the load was to be taken, with sufficient of the tether sitting above the ground surface. In some instances, the anchor needed to be set by pulling on the tether, or guy, to rotate or otherwise set the anchor plate in the soil.

If there was a rocky soil, or soil variation then the anchor had to be dug in and buried. This could take 25 minutes or more per installation. Alternatively, for a rocky soil a large strainer post was used. This is similar to the tent peg approach outline above. This could be a 250mm diameter post which was then driven up to 2 metres into the ground. With the ground being of varying consistency and density, for example with rocks distributed through the ground the post would often break. If this happened, then the entire post required removal and re-insertion. Improved systems, such as the drive-in ground anchor system sold under the trade name Duckbill™, supply anchors and tethers as one piece. A range of differing anchors for varying soil types is supplied.

Such a previous system required a user to choose and purchase the fully assembled anchor for the retention force and ground there were anchoring in. The anchors were supplied with the tether and anchor, e.g. large for soil, and smaller for rocky. This approach works well when the soil is of a consistent variety, e.g. always a certain density or always rocky with a known distribution. In New Zealand and Australia, and other countries over an area there will be a diverse range of soil types, loamy, clay, rocky, and there may even be all three in the one location that a ground anchor needs to be installed in. Therefore, with the prior art systems, if a user encountered differing soil types they had to use a complete assembly of a differing size.

In reality what this meant was that for an installation of say 400 units for nominally loamy soil, the user would also buy an additional 100 units of different size in the expectation they would encounter soil type different to what they purchased the majority of units for. This leads to additional cost and stock needing to be held, and which ultimately may not be used, and therefore wasted. Alternatively the installer may purchase a one-size anchor that is a compromise for the ground, in that it can be installed in a rocky soil and have a pull out strength much greater than required. The one-size anchor then may be also installed in loamy ground, but may only just reach the required pull out strength in the loamy soil. Thus the installation in rocky soil is overly difficult, and the loamy soil is easy. This again leads to waste of time and cost and compromise of anchor installed.

Once the anchor is inserted, and if necessary, set, then the load could then be attached to the anchor and retained.

In this specification where reference has been made to patent specifications, other external documents, or other sources of information, this is generally for the purpose of providing a context for discussing the features of the invention. Unless specifically stated otherwise, reference to such external documents is not to be construed as an admission that such documents, or such sources of information, in any jurisdiction, are prior art, or form part of the common general knowledge in the art.

It is an object of the present invention to provide an improved ground anchor and method therefor, or to overcome the above shortcomings or address the above desiderata, or to provide a user with a more rapidly customisable ground anchor that reduces excessive parts purchase, or to at least provide the public with a useful choice.

BRIEF DESCRIPTION OF THE INVENTION

In a first aspect the present invention consists in a ground anchor for installation in a ground, earth or similar substrate, to resist an applied load, comprising or including, A tether having a first end for connection to the applied load, and a second end for connection in ground, distal the first end,

A key plate rotably connected to the second end,

An anchor plate, selected from a range of size of anchors, the selection dependent on the ground conditions the anchor plate is to be installed in, the anchor plate having an aperture there through to receive and engage the key plate and retain the key plate at least in a first direction from the second end to the first end,

The assembly of the tether, key plate and anchor plate being capable of being driven into the ground by a driving shaft connected to the assembly, at least in a second direction, opposite the first direction, at an angle substantially equal to that of the applied load to the ground, thereafter the driving shaft can be removed, and the anchor plate is set in ground by pulling the tether in the second direction to at least in part rotate the key plate and anchor plate, such that a ground anchor can be established in ground to resist an applied load.

Preferably there is a carrier connected to the driving shaft between the driving shaft and the assembly.

Preferably the carrier is replaceable if necessary, for example if damaged or lost, and is retained by a replaceable connection for example a pin and retainer to retain it to the driving shaft. Preferably the anchor plate is in a first position of low cross-sectional area in the second direction when driven into the ground by the driving shaft, and then rotates to a second position of greater cross-sectional area in the second direction when set.

Preferably the rotation is about an axis that is orthogonal to the second direction.

Preferably the size of the anchor plate is also selected based on the applied load.

Preferably the ground conditions include a driving resistance of the ground, earth or similar substrate to the driving and or a withdrawal resistance of the ground anchor from ground earth or similar substrate when set.

Preferably the anchor plate is planar in form, or may be contoured to aid installation, setting or load retention.

Preferably the locking of the anchor plate to the key plate is a substantially rigid, non- rotational locking.

Preferably the driving is achieved through use of a prime mover and is either constant force or oscillating force.

Preferably the driving may be into a hole that has been predrilled.

Preferably the setting is achieved through use of a prime mover and is either constant force or oscillating force.

Preferably the assembly mates with the driving shaft at least via the anchor plate engaging in a first slot in the driving shaft, or part thereof, the slot parallel, or predominantly parallel to the second direction.

Preferably the anchor plate engages with the driving shaft, or part thereof, such that it is retained lateral to the second direction.

Preferably the driving shaft also engages with the key plate when driving.

Preferably the tether is either a flexible wire or similar or a rigid rod. Preferably the first end for connection is a first eyelet.

Preferably the second end for connection second eyelet.

Preferably the first eyelet and second eyelet are identical, and the tether is symmetrical about a midway point along its length.

Preferably the driving shaft has an engagement point to allow its removal in the first direction after driving.

Preferably the key plate is wider at a key plate first end, distal from its connection to the second end, such that the key plate first end retains the anchor plate in the first direction.

Preferably the key plate is “T” shaped when seen in side view.

Preferably the anchor plate is assembled to the tether and key plate by passing the tether and key plate through the aperture, such that the anchor plate is then retained by the key plate first end.

Preferably the aperture is a slot to allow passage therethrough during assembly of the first eyelet, second eyelet, and a key plate second end at a first orientation relative the key plate.

Preferably the aperture is shaped to allow assembly of the anchor plate in a second orientation relative the key plate.

In another aspect the present invention consists in a method of ground anchoring in a ground, earth or similar substrate to resist a load, comprising or including the steps of, Assembling a ground anchor by connecting a selected anchor plate, selected from a range of size of anchors, the selection dependent on the ground conditions, to a tether having a first end for connection to the applied load, and a second end for connection in ground, distal the first end, the second end having a key plate rotably connected thereto that retains the anchor plate at least in a first direction from the second end to the first end,

Connecting the assembled ground anchor in a first position to a driving shaft at a ground engaging end thereof,

Driving the driving shaft and assembled ground anchor into the ground at an angle substantially parallel to the load to be resisted, in a second direction, opposite the first direction,

Setting the assembled ground anchor by pulling on the tether in the first direction, such that the key plate and anchor plate rotate to a second position having a greater surface area at least of the anchor plate substantially orthogonal to the first and second directions, than in the first position,

Such that a ground anchor that can resist a tensile load in the first direction is formed.

Preferably the driving shaft is removed from the ground prior to the step of setting.

Preferably there is a carrier connected to the driving shaft between the driving shaft and the assembly.

Preferably the carrier is replaceable, if necessary, for example if damaged or lost, and is retained by a replaceable connection for example a pin and retainer to retain it to the driving shaft.

Preferably the rotation is about an axis that is orthogonal to the first and second directions.

Preferably the size of the anchor plate is also selected based on the applied load.

Preferably the ground conditions include a driving resistance of the ground, earth or similar substrate to the driving and or a withdrawal resistance of the ground anchor from ground earth or similar substrate when set.

Preferably the anchor plate is planar in form, or may be contoured to aid installation, setting or load retention.

Preferably the locking of the anchor plate to the key plate is a substantially rigid, non- rotational locking.

Preferably the driving is achieved through use of a prime mover and is either constant force or oscillating force.

Preferably the driving may be into a hole that has been predrilled or otherwise formed. Preferably the setting is achieved through use of a prime mover and is either constant force or oscillating force.

Preferably the assembly mates with the driving shaft at least via the anchor plate engaging in a first slot in the driving shaft, or part thereof, the slot parallel, or predominantly parallel to the second direction, when in the first position.

Preferably the anchor plate engages with the driving shaft, or part thereof, such that is retained lateral, or offset but parallel of the second direction.

Preferably the driving shaft also engages with the key plate when driving.

Preferably the tether is either a flexible wire or similar or a rigid rod.

Preferably the first end for connection is a first eyelet.

Preferably the second end for connection second eyelet.

Preferably the first eyelet and second eyelet are identical, and the tether is symmetrical about a midway point along its length.

Preferably the driving shaft has an engagement point to allow its removal in the first direction after driving.

Preferably the key plate is wider at a key plate first end, distal from its connection to the second end, such that the key plate first end retains the anchor plate in the first direction.

Preferably the key plate is T shaped when seen in side view.

Preferably the anchor plate is assembled to the tether and key plate by passing the tether and key plate through the aperture, such that the anchor plate is then retained by the key plate first end.

Preferably the aperture is a slot to allow passage therethrough during assembly of the first eyelet, second eyelet, and a key plate second end at a first orientation relative the key plate. Preferably the aperture is shaped to allow assembly of the anchor plate in a second orientation relative the key plate.

In yet another aspect the present invention consists in a kit of parts for a ground anchor, for installation in a ground, earth or similar substrate, to resist an applied load, comprising or including,

A tether having a first end for connection to the applied load, and a second end for connection in ground, distal the first end, connected to,

A key plate rotably connected to the second end,

An anchor plate, selected from a range of size of anchors, the selection dependent on the ground conditions the anchor plate is to be installed in, the anchor plate having an aperture there through to receive and engage the key plate and retain the key plate at least in a first direction from the second end to the first end,

An elongate driving shaft for connecting to the assembly of the tether, key plate and anchor plate, adapted to drive the assembly into the ground when in a first position in a second direction, opposite the first direction when attached to a prime mover, whereafter the assembly can be set by pulling in the first direction such that the key plate and anchor plate rotate to a second position having a greater surface area at least of the anchor plate substantially orthogonal to the first and second directions, than in the first position, such that the kit will allow a ground anchor to be installed in ground to resist an applied load.

Preferably the kit includes a range of sizes of anchor plate to enable selection for the ground condition.

In yet another aspect the present invention consists in a support assembly to support one or more items where a load from the one or more items is taken at least in part by a ground anchor as herein described when installed using a method as herein described.

In yet another aspect the present invention consists in a ground anchor as described herein with reference to any one or more of the accompanying drawings.

In yet another aspect the present invention consists in a method of ground anchoring as described herein with reference to any one or more of the accompanying drawings. In yet another aspect the present invention consists in a kit of parts for a ground anchor as described herein with reference to any one or more of the accompanying drawings.

In yet another aspect the present invention consists in a support assembly as described herein with reference to any one or more of the accompanying drawings.

As used herein the term “and/or” means “and” or “or”, or both.

As used herein “(s)” following a noun means the plural and/or singular forms of the noun.

The term “comprising” as used in this specification means “consisting at least in part of”. When interpreting statements in this specification which include that term, the features, prefaced by that term in each statement, all need to be present, but other features can also be present. Related terms such as “comprise” and “comprised” are to be interpreted in the same manner.

It is intended that reference to a range of numbers disclosed herein (for example, 1 to 10) also incorporates reference to all rational numbers within that range (for example, 1 , 1.1 ,

2, 3, 3.9, 4, 5, 6, 6.5, 7, 8, 9 and 10) and also any range of rational numbers within that range (for example, 2 to 8, 1.5 to 5.5 and 3.1 to 4.7).

The entire disclosures of all applications, patents and publications, cited above and below, if any, are hereby incorporated by reference.

This invention may also be said broadly to consist in the parts, elements and features referred to or indicated in the specification of the application, individually or collectively, and any or all combinations of any two or more of said parts, elements and features, and where specific integers are mentioned herein which have known equivalents in the art to which this invention relates, such known equivalents are deemed to be incorporated herein as if individually set forth.

Other aspects of the invention may become apparent from the following description which is given by way of example only and with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred forms of the present invention will now be described with reference to the accompanying drawings in which; Figure 1 shows an isometric view of the key plate for use in the present invention,

Figure 2 shows a side view of the key plate of Figure 1 ,

Figure 3 shows an isometric view of an anchor plate for use in softer ground, Figure 4 shows a plan view of the anchor plate, and its aperture and recess of Figure 3,

Figure 5 shows an isometric view of an anchor plate for use in hard or rocky ground, Figure 6 shows a plan view of the anchor plate and its aperture and recess of Figure 5,

Figure 7 shows an isometric of a tether for connection to the key plate, Figure 8 shows an isometric view of a driving shaft for driving the assembly of the key plate, anchor plate and tether into the ground with the replaceable carrier,

Figure 9 shows a detail close up at A, interrupted view of the driving shaft and carrier, of Figure 8, and at B a side view of the carrier end that drives the assembly,

Figure 10 shows a bottom view of the driving shaft and carrier for engaging and driving the assembly,

Figure 11 shows the tether, connected to the key plate, and the anchor plate being connected thereto, the anchor plate moving in a second direction relative to the tether and key plate,

Figure 12 shows a close up of the anchor plate assembled to the key plate and tether, Figure 13 shows an isometric close up of the engaging of the carrier of the driving shaft to the assembled key plate, anchor plate and tether, showing the offset, or over centre attachment of the tether relative to the anchor plate via the key plate, Figure 14 shows an isometric close up of the engaged carrier rand driving shaft to the assembled key plate, anchor plate and tether, the recess in the anchor plate providing further engagement, Figure 15 shows the driving shaft having driven the assembled ground anchor into the ground by the prime mover, in the second direction, the driving shaft having been partially removed from the assembled ground anchor in the first direction, Figure 16 shows the ground anchor in Figure 15 having been set and rotated to provide the load resistance, and

Figure 17 shows the ground anchor installed in Figure 16 with a load applied, in this case a plant support.

DETAILED DESCRIPTION OF THE INVENTION

Preferred embodiments will now be described with reference to Figures 1 through 17.

The assembled ground anchor 1 , shown installed in Figures 15 through 17 consists of a key plate 7 (Figure 1), anchor plate 8 (Figures 3 through 6), and tether 4 (Figures 7).

The key plate 7 in one form is shown in Figures 1 and 2 and is for engaging the anchor plate 8. A key plate first end 27 is present for engagement with the anchor plate 8. In the embodiment shown this end 27 is wider than a key plate second end 28, in other words the key plate 7 is wider at one end (the first end 27) than its opposing end (the second end 28), and in the form shown in T shaped. This will be shown to engage with the aperture ?? to retain anchor plate 8 below. There may be other forms of interconnection between the key plate 7 and anchor plate 8 that allow similar functionality, such as threaded, sleeved, wedge lock, or similar. At the key plate second end 28 there is the location for engagement with the tether 4. In the embodiment shown this is a key plate aperture 30. Its engagement with the tether 4 will be described below.

In the preferred form the key plate 7 is manufactured from high strength plate steel and has a yield strength between 600 and 1200 MPa, and preferably is 700 MPa.

The tether 4 may be a flexible wire or a more rigid rod - though over the likely supplied lengths of up two metres or more in length for a thickness of 8mm to 15mm the tether is likely still to have some flex, even when made from rod. At each first end 5 and second end 6 of the tether 4 there is an eyelet, as a first eyelet 24 and second eyelet 25. In the preferred form the tether 4 is symmetrical about a midway point along its length, but this is not necessarily so, and the eyelets or connections points at each end may vary as well as the cross section of the tether. In the preferred form this cross section is circular, but may be other cross sections such as rectangular, square, triangular or similar. In other forms the tether may be formed from multiple sections to provide a variable length, or multiple tethers are able to be connected to provide a variable length.

In one embodiment the eyelets 24 and 25 are formed from U shapes of bent rod which are welded to the rod or connected to the wire forming the tether 4. It has been found that such a U or circular shape provides less friction and resistance during the installation of the assembly including less resistance to the soil, rocks and other items that may be present as the ground anchor is driven or inserted. Such a U-shaped eyelet, or other form producing an aperture for attaching to may be formed or attached in several ways, including, but not limited to welding, forging, or drilling.

When welding the U shape to the rod of the tether 4 for example, the key plate 7 is preferably attached to the U shape first by passing one leg of the U through the key plate aperture 30, and then welding or otherwise connecting the U shape to the rod, or wire (for example by swaging). In other forms the key plate 7 may be connected to the tether 4 by a bolt or similar fastener.

The connection of the key plate 7 to the tether 4 is a rotating one, such that the key plate 7 can rotate relative to the tether 4. In the preferred form the rotation is at least about an axis that is orthogonal to the main or longitudinal direction 31 of the tether 4. An eyelet or similar connection as shown and discussed between the tether 4 and the key plate 7 will allow other forms of rotation also and these additional degrees of freedom may allow greater ease of insertion, engagement or retention in the ground 2. This engagement is shown, at least for example in Figure 11.

In the preferred form the tether 4 is made from a high tensile hard steel and has a yield strength of 600 to 1300 MPa, and preferably has a yield strength of about 700 MPa.

Preferred forms of the anchor plate 8 are shown in Figures 3 and 4 for a soft soil and Figures 5 and 6 for a harder or rocky soil. The anchor plate 8 is preferably formed from a high strength plate steel. For example, the anchor plate 8 is manufactured from 6mm to 12mm thick high strength steel, and preferably from 8 mm thick steel such as that sold under the trade name STRENX™ with a yield strength of between 600 to 1300 MPa, preferably 700 MPa. In tension loading this material for the anchor plate 8 and also the key plate 7 has been shown to exceed a failure force of 11 metric tonnes.

The withdrawal resistance or pull-out force is at least based on the soil or ground 2 make up, for example soil density, water content and presence or rocks or other inclusions 37 such as shown in Figure 17 that are harder than the surrounding ground 2 makeup, and the plan area of an anchor presented in the direction of pull out. A soil only ground 2 will have a lower pull-out force than a rocky and soil ground for the same plan area of anchor.

Therefore, a harder or rocky soil typically has a higher withdrawal resistance, that is the force needed to pull out for an anchor plate that is at or toward perpendicular to the direction of pull than a softer soil with the same sized plate, or same plate area presented in the pull-out direction. It is to be understood that while ideally an anchor plate 8 will fully rotate when set into the second position (retaining position), thus presenting its full plan area 18A or 19A. However, the anchor plate 8 may only partially rotate when set in the second position, for example should it hit an inclusion in the ground, for example a rock.

In this situation it will still have a plan area presenting in the pull-out direction, but this is less than the full plan area of that plate.

Our investigations have shown that for hard or rocky soils or ground 2 a smaller plan area 19A anchor plate 8 such as that shown in Figures 5 and 6 will have an effectively high pull-out force or withdrawal resistance to meet the necessary pull out requirements. Such a smaller anchor plate 8 of lower plan area 19A when in the insertion or driving position (first position) is also easier to drive or insert into the hard or rocky ground, due to its low cross section 18A (that is its edge cross section 18A when in the first position compared to its planar area 19A when set at or toward the second position).

Similarly, a larger plan area 19B of a larger anchor plate 8, such as shown in Figures 3 and 4 has a better resistance to pull out force, or retention in a soft soil, and also, even though it will have a greater edge cross section 18B in the first position (than that of the smaller anchor plate 8 in Figures 5 and 6) this low edge cross section 18B when in the insertion or driving position (first position), can be driven into such soft soils easily. Even though its edge cross section 18B is greater than the edge cross section 18A of the smaller anchor plate 8, the material it is driven into, is softer than the hard, or comparatively harder ground, thus the driving forces of the two different sized plates into the different hardnesses of ground are similar, or at least not massively different.

The anchor plate 8 has an aperture 9 at or near its centre. The aperture, as will be described below, receives the key plate 7 and retains the anchor plate to the key plate 7 and thus the tether 4. The aperture 9 here is shaped to allow the second key plate end 28 to pass through the anchor plate, but not the wider first key plate end 27 - thus the shoulders or wider part of the key plate 7 is held on one side of the anchor plate 8 and cannot pass through. The aperture 9 here has a further slot to allow passage therethrough of the eyelets of the tether 4. The aperture 9 may be differently shaped as needed depending on the shape of the tether 4 and the connection method of the key pate 7 to the anchor plate 8. The aperture 9 may also allow a second orientation of the anchor plate 8 to the key plate 9 if desired. Though two sized anchor plates 8 are shown there may be a variety of them provided each of different size, thickness and plan or main area 18 depending on the soil or ground type into which they are to be inserted.

The driving shaft 11 is shown in Figures 8 through 10. In the preferred form the driving end 33 of the driving shaft 11 is removable as a carrier 35. This allows for replacement or repair if damaged or lost, for example if it snags something while being driven. The driving end has a first slot 22 and also the second slot 23. These engage with the assembly of the key plate 9 and anchor plate 8 and hold them in the first position for driving, and stiffen the anchor plate 8 when it is being driven in. This enables driving through or past obstructions in the ground and keep its desired direction and angle.

Each of the anchor plates 8 in the preferred form shown has a contour 32, in this case a notch, as part of a complimentary engagement between the anchor plate 8 and the driving end 33 to provide better engagement with the driving shaft 11 when inserting the anchor 1 into the ground 2. In particular, the contour 32, is complimentary to the bottom of the first slot 22 and overlaps that bottom partially. This prevents or reduces lateral movements of the anchor plate relative to the driving end 33, thus further aiding in keeping the driving shaft 11 and ground anchor assembly on course when driving. As earlier described the tether 4 is connected to the key plate 7, and in the preferred form is supplied to the user in this way as a sub- assembly. The user then assembles the sub- assembly of the tether 4 and key plate 7 to the chosen anchor plate 8 for the desired ground condition and pull-out resistance. Some installations may require a lower pull-out resistance, than other for the same or similar ground condition. Therefore, a smaller plate may be chosen for the lower pull-out resistance which in turn allows an easier installation as the driving force required to drive the ground anchor assembly in is less.

The two are assembled as shown in Figure 11 by passing the first end 5 and, in the embodiment shown, the first eyelet 24 of the tether 4 through the aperture 9 of the anchor plate 8. The anchor plate 8 is then slide along the tether in the second direction from the first end 5 to the second end 6 of the tether toward the second eyelet 25, and oriented so the contour 32 is upper most, or pointing down the length of the tether toward the first eyelet 24 when the key plate rotates about its axis into the first position 36, that is pointing in the first direction, as shown in Figures 12 through 14.

The anchor plate 8 is then engaged to the key plate 7, and cannot rotate relative to the key plate 7, but the key plate 7 and anchor plate 8 can rotate relative to the tether 4.

The driving shaft 11 as shown in Figures 8 to 10 is used to drive or insert the assembly of the ground anchor 1 into the ground 2. The driving shaft 11 as shown is elongate and has a driving end 33 where it engages the ground anchor assembly, in particular the key plate 7 and anchor plate 8, and a driven end 34 where a prime mover 21 engages the driving shaft 11 to drive it and the ground anchor 1 into the ground 2. The driving shaft 11 is typically, but not necessarily longer than the tether, for example may be about 2 metres long, and there may be the ability to join multiple lengths of driving shaft together to drive the ground anchor 1 in the desired length.

Along the length of the driving shaft, there is an engagement point 26 to attach a pull from the, or another prime mover to pull the driving shaft 11 out from ground 2 when driving the ground anchor 1 has been driven in.

The driving end 33 may be replaceable as a separate carrier 35 to allow for damage or loss when driving or removing and may be retained to the driving shaft using a pin and retainer 15. The driving end 33 is at least made from a 4140 or similar grade material and may be shaped by milling or similar. The driven end may be braced as shown in Figure 9 for additional stiffness and may also be removable and replaceable as needed.

The driving end 33 has a complimentary engagement with the ground anchor 8 and the contour 32, and also the key plate 7 as earlier described. The engagement is in the form of a first slot 22 that is just wider than the thickness of the anchor plate 8, for example between 8 to 12mm, and in the embodiment shown, is just over 8mm wide (for an 8mm thick anchor plate 8). A second slot 23 is also optionally present and engages the thickness of the key plate 7, and at least bares on the back of the key plate 7, the engagement as shown in Figures 13 and 14.

The method of installing and use of the ground anchor will now be described.

The ground 2 which the anchor is to be installed in is tested or otherwise its composition is known and the correct sized ground anchor for the pull-out force needed is selected and assembled into the ground anchor as previously described. If necessary, a hole is formed to receive the ground anchor, for example by drilling or otherwise, or an existing hole in the ground may be used. In most installations however a hole is not needed. The ground anchor 1 is assembled as earlier described with the correct sized anchor plate for the known ground 2 make up and then engaged to the driving shaft 11 in the first position and these are then connected to a prime mover 21 as shown in Figure 15. The prime mover 21 , such as an excavator or excavator with vibratory plate drives the driving shaft 11 via the driven end 34 and hence the ground anchor 1 into the ground 2 to the correct depth in the second direction 10 as shown in Figure 15.

The prime mover 21 such as an excavator then pulls the driving shaft 11 out by connection to the engagement portion 26. If for any reason prior to setting it is necessary to remove the ground anchor, this may be achieved by pulling on the tether 4. The anchor plate 8 and key plate 7 cannot rotate as they are retained by the driving end 33, and so the anchor plate 8 and key plate 7 assembly will pull the driving shaft 11 out with it. Some withdrawal force may be applied to the driving shaft 11 also, provided this is less than that applied to the tether to the driving shaft does not disengage from the anchor plate 8 and key plate 7.

The prime mover 21 is then connected to the first end 5, for example first eyelet 24 of the tether 4 and pulls on this in the first direction 12 to set the ground anchor 1. In doing so, due to the off or over centre relation of the key plate second end 28 connection being away from the centre of rotation of the anchor plate 8 and key plate 7 assembly the anchor plate 8 and key plate 7 is rotated from its first position 36 in a low cross section 18 orientation towards the second position 37 where the main plan area of the anchor plate 8 is presented being of greater plan area in the first and second directions. It is this second position and greater area 19 that resists the pull out of the load in the first direction 12. It is to be noted, that while desirable for full rotation by 90 degrees or so about the key plate aperture 30 to provide maximum area, that is the normal of the major surface of the anchor plate is parallel to the tether 4 or first direction 12, this may not be possible because of the soil and inclusions. Instead, only partial rotation from the first position occurs. This is still acceptable provided the minimum pull out resistance is achieved.

Pull-out resistance is checked by loading the tether slightly in excess of the maximum pull out resistance force required for the application. If the ground anchor 1 stays in position, then setting has been successful. If the ground anchor moves and starts to pull out, then it may be removed, or left in place, and another ground anchor installed and checked.

If the installation is successful and meets the minimum pull out resistance the load 3 may be connected when necessary to the tether 4 directly or otherwise. In the example shown the load is a plant support 29 or could be a hail or rain protection system. In these applications there are multiple ground anchors 1 required.

The angle 13 of insertion and loading could be at any angle from 5 degrees to 90 degrees to the ground, but preferably is around 35 degrees to the ground level.

The present invention therefore provides a quick and efficient ground anchor system that can be quickly and efficiently deployed across a number of ground types with minimal additional parts for varying ground types and having high pull-out resistance.

The foregoing description of the invention includes preferred forms thereof. Modifications may be made thereto without departing from the scope of the invention.