27-04-1976 дата публикации
Номер: US0003952523A1
Принадлежит:
The method of securely placing a screw-type anchor in the earth without unduly disturbing the surrounding soil, including the step of enveloping the anchor's shank in a special tubular mandrel. The mandrel has a helical flight near its bottom end, with a pitch that is substantially the same as the anchor's flight, such that the mandrel's flight constitutes an effective extension of the anchor's flight. When the anchor/mandrel combination is rotated in a first direction, the two elements will burrow as a unit into the ground. After the mandrel has been rotated sufficiently to put the anchor at a designed depth in the earth, rotating the mandrel in the opposite direction causes it to separate from the anchor and back out of the earth through substantially the same cut that was made when the anchor was turned into the earth. A preferred manner of applying torque to the mandrel is to utilize an electrically powered portable torque unit, in which the direction of rotation (clockwise or counterclockwise ...
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