This invention relates to an apparatus for fastening a hollow composite pole to the ground where a slit formed opening is present in the ground. The invention also relates to a method for fastening a hollow composite pole to the ground.
It is known to fasten composite poles in the ground by excavating a recess, and thereafter positioning the composite pole in the recess and fill in around the pole. Regarding poles for overhead power lines, such a method will often involve relatively large environmental damage, particularly when a recess is made in rock. When fastening poles by use of said method, frost damage may occur due insufficient draining.
It is also known to mount a composite pole to a column raised from the ground. The column may be made from concrete and having reinforcement that extends into the ground. The composite pole may be inserted over the column. If the column is made from concrete, it is necessary to bring the concrete to the position of the column often by use of a helicopter, or make concrete at the position of the column. Both methods comprises extra costs and work.
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The invention has for its object to remedy or to reduce at least one of the drawbacks of the prior art, or at least provide a useful alternative to prior art.
The object is achieved through features, which are specified in the description below and in the claims that follow.
The invention is defined by the independent patent claims. The dependent claims define advantageous embodiments of the invention.
In a first aspect, the invention relates more particularly to fastening element in accordance with claim 1.
The invention concerns having a circular slit-formed opening, in the ground, where a fastening element is positioned in the slit-formed opening. The fastening element has a conical upper portion above the ground and a lower cylindrical end portion. A hollow composite pole, has a complementary conical inner portion at its lower end, and is positioned on and abutting the fastening element.
By hollow means that the composite pole must have an inner opening, at least in the portion that is moved over the fastening element.
The slit formed opening may be formed by drilling or hammering a body into the ground.
The fastening element may be equipped with drill elements at its lower end portion to enable the fastening element to be used as a drill.
The drill elements may comprise metal or ceramic material or combinations thereof.
In a second aspect the invention relates more particularly to a method for fastening a hollow composite pole for overhead power lines to the ground in accordance with claim 6.
The method comprises fixing the fastening element to the ground, for instance by adhesive or a concrete based material.
The method may comprise making the slit formed opening by drilling into the ground.
The method may comprise making the slit formed opening by hammering the fastening element into the ground.
The method comprises providing the lower end portion of the fastening element with drill elements and drilling the fastening element into the ground.
The fastening element may be made from composite material or metal or combinations thereof.
If parts of the ground that is positioned on the inner side of the slit should loosen or where it is advantageous to have it removed partly or fully, the material on the inner side of the slit may be at least partly removed.
When drilling in soil or march, it may be advantageous to have frost in the ground to avoid movement in the ground during drilling.
Tests show that the drill or the fastening element must be aligned with the vertical axes prior to being moved into the ground.
The apparatus and method according to invention solves the problem of fastening a hollow composite pole to the ground in a relatively simple and cost effective way.
In the following is described examples of preferred embodiments and methods illustrated in the ac-companying drawings, wherein:
On the drawings, the reference numeral 1 denotes a drill that by the help of a power drill 2 is under displacement into the ground 4. The ground 4 may constitute for example rock, soil, or march, alternatively combination thereof.
The power drill 2 is typically aligned and is fixed to the ground 4 or another suitable, not shown device. There after the power drill 2 that may be electrically or hydraulically driven, displaces the drill 1 into the ground 4 while rotating the drill 1. Thus, a slit formed opening 6 is formed in the ground 4. The drill 1 is then removed from the slit formed opening 6.
A composite pole 8 that has been moved into the slit formed opening 6 is shown in
In an embodiment of the invention, shown in
In some cases, as when the ground 4 mainly constitutes suitable soil, the fixing element 10 may be forced into the ground 4 by hammering.
In a further alternative embodiment as shown in
A typical drill element 14 is shown in
The fixing element 10 shown in
It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. Use of the verb "comprise" and its conjugations does not exclude the presence of elements or steps other than those stated in a claim. The article "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.
This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.