GB2171732A - Earth anchor - Google Patents

Abstract

An earth anchor has a tubular shank 1, a shoe 2 and a single fluke 3 which, when driven down the shank, is deformed to arcuate shape, by oppositely spaced integral guide surfaces 10, 13 in the shoe, as the driven fluke passes through and projects laterally from the shoe as an arcuate hook. <IMAGE>

Description

SPECIFICATION Earth anchor This invention reiates to earth anchors to be driven into the ground and provide high resistance against withdrawal by deformable fluke members driven to project laterally from the anchor into the ground.

Such earth anchors usually consist of a tubular shank, housing fluke members in the form of deformable metal bars, and an earthpenetrating shoe, carried by the tube, with an inner end, inside the tube, shaped to be encountered by the fluke' members and deflect them laterally, to project into the ground, when the fluke members are driven down the tube.

Various shapes of shoes and coacting surfaces, provided by the end of the tube or additional guide members, have been proposed but the problem remains of providing an effective and robust construction which is simple to make and consequently economical.

The basic concept of the present invention is an earth anchor which can be made from only three parts, namely a tubular shank, a shoe and a fluke member.

More particularly, the invention comprises forming the shoe with integral guide surfaces effective to control bending of the fluke member without involving any interaction with the tube or any additional guide member.

In practice, such a self-contained fluke-guiding shoe can be made economically as a metal casting which is robust and easily secured to the tubular shank. For this latter purpose, a guiding passage in the shoe, for the fluke member, also provides an opening into which part of the end wall of the tubular shank can be deformed so as to key strongly into the shoe.

Accordingly, the invention provides an earth anchor comprising a tubular shank carrying an earth-penetrating shoe, to be driven into the ground, the shank housing a longitudinally extending fluke member longitudinally displaceable in the shank and guided for the lower end of the fluke member to project laterally from the shank when the fluke member is driven downwardly in the shank, the earth-penetrating shoe having a guiding passage for the fluke member and being formed integrally with transversely oppositely directed and longitudinally spaced surfaces defining an arcuate path for the fluke member when driven.

Preferably only one fluke member is provided, with a substantial constant cross-section as large as can be conveniently housed in the tube, this providing for a relatively strong fluke giving a dependable anchorage as compared with multiple flukes which do not occupy the capacity of the tubular shank so efficiently.

An embodiment of the invention is illustrated, by way of example, on the accompanying drawing, in which: Figure 1 is an axial section of the lower end of an earth anchor, Figure 2 is a side elevation, in the direction of the arrow on Fig. 1, and Figure 3 is a side elevation similar to Fig. 2 but showing a modification.

The earth anchor illustrated comprises a shank in the form of a steel tube 1, a cast iron shoe 2 and a mild steel fluke member 3.

The inner end of the shoe 2 is cast with a passage-way 4 into a lateral opening 5 in which a part 6 of the wall of the lower end of the tube 1 is deformed, as a rectangular dimple, to key the tube 1 firmly to the shoe.

The shoe 2 is also formed with a peripheral ledge 7 against which the rim 8 of the end of the tube 1 abuts. This provides positive driving abutment of the tube 1 on the shoe 2 and enhances strong connection of the tube to the shoe by reaction of the dimple 6 against the upper border of the opening 5.

The passage-way 4 of the shoe 2 lies between an upper bridge-portion 9 of the shoe presenting a substantially transversely directed but slightly inclined guide surface 10 for the fluke member 3 of which the arcuately preformed lower end 11 enters the passage-way 4.

A lower outlet 12 from the passage-way 4 is defined by an inclined guide surface 13, transversely oppositely directed and longitudinally spaced from the guide surface 10, and by side surfaces 14 between which the rectangular cross-section fluke member 3 is an easy sliding fit.

It can be seen from Fig. 1 that when the fluke member 3 is driven, by striking its cranked upper end 15 with a suitable tool passed down the tube 1, the lower end 11 is guided between the opposed and longitudinally spaced shoe surfaces 10 and 13 to emerge from the outlet 12 and penetrate the ground with an arcuately hooked configuration imposed by the constraint of the shoe surfaces 10 and 13, as indicated in broken lines in Fig. 1.

As shown in Fig. 3. the outlet 12 can be formed on the skew, with inclined side surfaces 14, so that the fluke member emerging from the shoe is guided with an additional lateral bending component, giving the fluke a somewhat helical or three-dimensional configuration to enhance ground-grip. As indicated in broken lines in Fig. 1, the shoe 2 may be formed with a flange or web 16 to provide a guiding support for the fluke beyond the surface 13.

The following is a statement of features embodied by the invention.

(a) An anchoring device comprising a hollow tube, an earth penetrating end secured to one end of the tube and having a part extending into said one end of the tube, this part being configured to provide deflecting surfaces leading towards the exterior of the said anchoring device, these deflecting surfaces forming a guideway from the interior of the tube to the exterior of the anchoring device through an opening below said one end of the tube, and associated with the guideway and dimensioned to be driven within the tube in the direction thereof within the guideway and thence outwardly of the anchoring device a single elongate anchoring element of deformable metal which, apart from an optional earth penetrating point formed thereon, is of substantially constant cross-section and resistance to bending throughout its length.

Subordinate features are as follows: (b) The opening to the exterior of the anchoring device is defined partly by the tube and partly by the penetrating end.

(c) A separate supporting web is located externally of the tube to support the outwardly driven anchoring element.

(d) The supporting web is formed on the penetrating end.

(e) The leading end of the anchoring element is pre-formed to a radius of curvature before assembly within the anchoring device.

(f) The pre-formed radius of curvature of the anchoring element associated with its guideway prevents movement of the said element away from the direction of penetration of the anchoring device.

(g) The anchoring element, except for any pre-formed leading end, is located along the axis of the tube or towards the side opposed to the opening to the exterior of the anchoring device.

(h) The anchoring element is located towards the side opposed to the opening, and the upper end of said element is bent towards or beyond the axis of the tube to form a larger striking area for means of driving the element downwards.

(i) A part of the tube towards its lower end is depressed inwardly to form a dimple engaging with a part of the penetrating end to prevent separation of said penetrating end from the tube.

(j) Deflecting surfaces are operable to deform the associated anchoring element in two directions, whereby the outwardly deflected anchoring element is caused to follow a threedimensional path.

Claims (11)

1. An earth anchor comprising a tubular shank carrying an earth-penetrating shoe, to be driven into the ground, the shank housing a longitudinally extending fluke member longitudinally displaceable in the shank and guided for the lower end of the fluke member to project laterally from the shank when the fluke member is driven downwardly in the shank, the earth-penetrating shoe having a guiding passage for the fluke member and being formed integrally with transversely oppositely directed and longitudinally spaced surfaces defining an arcuate path for the fluke member when driven through the shoe.

2. An earth anchor according to claim 1, in which only one fluke member is provided, initially for the major part of its length extending along the tubular shank on one side of the axis, and the guiding passage in the shoe crosses the axis to lead the fluke member, when driven, across the axis to emerge from the opposite side as an arcuate hook.

3. An earth anchor according to claim 1 or 2, in which the lower end of the fluke member is initially arcuately preformed and lies in the guiding passage in the shoe.

4. An earth anchor according to claim 1, 2 or 3, in which the shoe has a spigot which is inserted into the lower end of the shank, as into a socket, and forms the major part of the guiding passage with a downwardly and transversely directed guiding surface on an upper bridge-portion of the spigot and an upwardly and oppositely transversely directed guiding surface in the shoe below the spigot.

5. An earth anchor according to any foregoing claim in which the shoe has a spigot which is inserted into the lower end of the shank, as into a socket, and a peripheral ledge is formed around the shoe at the base of the spigot against which ledge the lower end of the shank abuts.

6. An earth anchor according to claim 5, in which the guiding passage in the shoe provides an opening into which part of the lower end of the wall of the shank is deformed to key the shank to the shoe with the lower end of the shank in tight abutment against the peripheral ledge of the shoe.

7. An earth anchor according to any foregoing claim, in which the guiding passage has a lower outlet opening laterally through the shoe below the lower end of the shank which defines the upper border of the outlet.

8. An earth anchor according to any foregoing claim in which the shoe is formed with a lateral projection below a lower outlet opening from the guiding passage and the projection forms a guiding support for the fluke beyond the outlet.

9. An earth anchor according to any foregoing claim, in which the upper end of the fluke member is cranked to form a driving anvil for a tool passed down the shank.

10. An earth anchor according to any foregoing claim, in which the guiding passage opens from the shoe by an outlet formed on the skew so that the emerging fluke is given a somewhat helical or three-dimensional configu ration.

11. an earth anchor substantially as described with reference to the accompanying drawing.