US3382628A - Ground anchor - Google Patents

Description

May 14, 1968 w. E. wAlrE GROUND ANCHOR Filed sept. 2e, 196e WILL/AM. E. WAI/TE.

United States Patent O 3,382,628 GROUND ANCHOR William Edmund Waite, Thnrland, Crookshury Road, Rnnfold, Surrey, England Filed Sept. 26, 1966, Ser. No. 581,300 Claims priority, application Great Britain, Sept. 28, 1965,

,273/65 2 Claims. (Cl. 52--157) ABSTRACT F THE DISCLOSURE An adjustable ground anchor is disclosed in which the shaft length can be changed by rotation of one part of the shaft with respect to another where they are joined at a threaded connection. The smaller shaft part extends the entire length through a hollow portion of the shaft and is prevented from being pulled out therefrom by a stop means on the remote anchor blade end thereof.

This invention relates to ground anchors, as used for example for the anchoring of cables serving to hold fence poles, telegraph poles and the like in position.

A well known construction of ground anchor incorporates a shaft having a helical anchor blade. The device is driven into the g-round by engaging a suitable tool 0r rotary drive with the shaft and rotating the anchor to cause the -blade to screw itself into the ground to an adequate depth. A cable connection is then made to the protruding end of the shaft.

It is desirable, with such ground anchors, to provide for some degree of adjustment of the assembly of cable and anchor, e. g. to take up slack which may occur in the course of time. One common means used hitherto has consisted of a turnbuckle incorporated along the length of the cable, or between the cable and the shaft of the anchor.

The provision of two separate items, i.e. the anchor and the turnbuckle, has disadvantages in that a number of separate connections must be made between the anchor, the turnbuckle, and the cabfe, and two separate items must be stored, transported and handled. It is accordingly the object of the present invention to provide an improved construction of ground anchor which incorporates an integral means for adjustment of its length, whereby -adjustment of cable tension can be carried out by adjustment of the anchor itself, and the need for a separate turnbuckle is eliminated.

According to the present invention, a ground anchor comprises a shaft with two portions engaged one to the other by threading, an anchor blade on one such shaft portion, and means for connecting a cable on the other shaft portion, the axial separation of the anchor blade and the ca'ble connecting means `being adjustable by rotation of one shaft portion with respect to the other.

With such an arrangement, adjustment of the cable tension may be obtained merely -by rotation of that portion of the shaft which protrudes from the ground, with respect to the other portion having its blade buried in the ground.

To enable the respective portions to be rotated readily, the cable connecting means preferably includes a cable attachment element which is freely rotatable with respect to the shaft portion on which it is provided. Such an element may be, for example, in the form of a swivel eye.

One portion of the shaft may conveniently be a tube carrying an anchor blade, the other portion being a stem threaded coaxially into the tube, a protruding end of said stem carrying the cable connecting means.

In order to reduce the amount of internal threading to a minimum, it is convenient to make the tube shorter 3,382,628 Patented May 14, 1968 than the stem and internally threaded for only part of its length, the necessary full length of adjustment being obtained by forming a male thread along a somewhat longer length of the stem. In such a construction, to protect the exposed threading of the stem, the tube may carry at one end a tubular extension arranged coaxially and with clearance about the stem, and which accordingly protects the thread against physical damage and corrosion.

Because the normal place of use of such ground anchors is in the ground and out of doors, there is considera'ble liability to corrode. For this reason, it is desirable to galvanise the device at the exposed portions. On the other hand it is not convenient or desirable for ease of manufacture, to galvanise the threaded portions. Accordingly, the tubular extension covering the male threading of the stem may lalso serve, during plating, as a means of masking off the threading from the galvanising bath. For this purpose, any convenient temporary seal may be introduced at the mouth of the extension to seal the gap between it and the threaded stem.

In a preferred arrangement, the other end of the stern, remote from the cable connection, carries a protruding head of greater diameter than the bore of the tube, said head being preferably pointed to facilitate entry of the anchor into the ground.

Such a head may 'be of generally conical cross-section and preferably has its base of the same diameter as the exterior of the tube. The head may also serve as an end stop to prevent the threaded stem from being completely disengaged from the tubular portion.

The shaft portion carrying the anchor blade may be provided with a multi-faceted exterior for engagement with a correspondingly faceted key of a power drive means.

The shaft portion carrying the cable connecting means may be provided with any suitable formation to facilitate its engagement with a tool for rotation with respect to the other shaft portion, e.g. a faceted nut welded onto it. Said nut may also serve as a stop for the adjustment of the stem in the `downward direction.

In order that the nature of the invention may be readily ascertained, an embodiment of ground anchor in accordance therewith is hereinatfer particularly described with reference to the accompanying drawing in which the single iigure is a side elevation with parts shown in section.

In the anchor illustrated, there is provided a two-part shaft including a short heavy-gauge outer tube 1 having an internal threading 2 for about one-fifth of the length of its bore from the top end downwards. Externally the tube is of square or other multi-faceted cross-section. At an approximately central position along the tube there is Welded a helical blade 3. Coaxially onto the upper end of the tube 1 there is welded a somewhat shorter length of relatively light-gauge conduit 4 which has an internal diameter greater than that of the threading and which is intended to act as a shield. Within the tube 1 and conduit 4 there is disposed a -stem 5 consisting of a piece of solid rod of circular cross-section and threaded externally at 6 for about the central third of its length, The threading 6 is engaged in the threading Z of the tube 1. The lower end of the rod 5 has a coaxial conical head 7 welded onto it, and the greatest diameter of the head is larger than the diameter of the bore of the tube 1.

The conduit 4 lits with clearance about the stem, and in practice it would be convenient `to provide a packing adjacent the open upper end of the conduit to provide a seal against dirt and moisture. Such a packing may also serve to prevent deposition of plating metal on the thread 6, when the stem is appropriately threaded into the tube 1.

The upper end of the stem 5 has an enlarged head 8 which serves to retain a freely rotatable swivel eye 9 for attachment of the usual cable.

Below the eye 9 there is welded a square-section nut 10 to serve for engage-ment by a Spanner (not shown) for rotating the stem.

When the anchor is to be driven into the ground, the threaded stern 5 is retracted upwardly until the conical head 7 is butted up against the lower end of the tube 1, thereby sealing the lower end of the tube against the entry of soil. The anchor is then rotated by means of a power-operated device having a tubular key with internal facets which rnate with the faceted exterior of the tube 1. This rotation causes the blade 1 to be driven down into the ground.

After the usual cable has been attached to the swivel eye 9, the tension of the cable can be adjusted by r0- tation of the stern 5, using a spanner engaged with the nut 10. The stern can be adjusted axially through the tube 1 for the whole of the length of threading of the stem, say about twelve inches in an anchor of length approximately three feet.

I claim:

1. A ground anchor comprising a shaft having a tubular portion carrying a radially projecting rigid anchor blade, a stern portion threaded coaxially into said tubular portion, said tubular portion and stern portion being rotatable one with respect to the other for lengthening and shortening the shaft according to the direction of relative rotation imparted to said shaft portions, said stem portion having a first end protruding from said tubular portion and carrying a rotatable cable connector means, said stern portion having a second end protruding from said tubular portion and carrying a head of greater diameter than the bore of the tubular portion.

2. A ground anchor comprising a shaft having a tubular portion carrying a radially projecting rigid anchor blade, a stern portion threaded coaXially into said tubular portion, said tubular portion and stem portion being rotatable one with respect to the other for lengthening and shortening the shaft according to the direction of relative rotation imparted to said shaft portions, said stem portion having a first end protruding from said tubular portion and carrying a rotatable cable connector means, and stop means on the stern portion and on the tubular portion positioned to abut to prevent the stem portion from being entirely removed from the tubular portion.

References Cited FRANK L. ABBOTT,

G. W. HORNADAY, R. S. VERMUT, P. C. FAW,

Assistant Examiners.

Primary Examiner.

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