Hydraulic and earth engineering – Foundation – Columnar structure
Reexamination Certificate
1999-03-18
2001-04-03
Bagnell, David (Department: 3673)
Hydraulic and earth engineering
Foundation
Columnar structure
C052S157000, C175S098000
Reexamination Certificate
active
06210077
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a mechanical ground anchor, particularly to a ground anchor that is reusable and that provides a reactive force resistance body when subjected to loading.
2. Description of Background Information
Up to the present, a straddle type of the mechanical anchor is well known as a ground anchor available for such a loading. As one of the straddle type of mechanical anchors, a self-boring type is known as disclosed in Japanese Patent Application No. HEI 4-13496 of the same Applicant where a cylindrical shaped anchor body divided into two parts is connected to a head plate mounted at the bottom end of the drilling rod by using a joint pin. This mechanical anchor is designed so that the anchor body could be straddled taking the form of an inverted V-shape by means of a jack provided in the anchor body when it reaches a certain depth by self-boring. For reasons that such existing mechanical anchor is designed so as to join the anchor body to the head plate by using a pin joint, however, there were the following points at issue:
(1) In the case of such a pin-joint, its structural strength such as a magnitude of its rotational torque and/or tensile strength depends on its section performance such as the length and/or diameter of the pin, while, by reason of the limited structural space of the mechanical anchor, the available size of the pin is limited and its rotational torque and/or tensile strength are restricted as a result.
(2) The magnitude of its rotational torque while being bored remaining straddled depends on the soil foundation hardness and depth to be bored. For this reason, the existing mechanical anchor could not be applied to such hard soil foundation as pebbly stratum and/or extremely deep excavation in many cases of the self-boring.
(3) Tensile strength while the anchor body is applied remaining straddled also depends on section performance of the pin. For this reason, pulling resistance force depending on the soil foundation could not always be maximized.
(4) Because the straddled anchor body takes the form of cylinder divided into two parts that rotate during boring, and due to the condition that only its upper end is joined to the boring rod, the existing mechanical anchor has a weakness during rotary boring.
(5) In collapsible soil foundation, it is often effective to strengthen boring walls by means of injecting a soil stabilizer such as bentonite liquid into the boring wall and then straddle the anchor body. It is, however, impossible to inject such soil stabilizer with the existing mechanical anchor from a structural point of view.
SUMMARY OF THE INVENTION
It is a general object of this invention to provide an improved mechanical ground anchor enabling a considerable pulling resistance force by solving the problems of the prior art due to the pin joint, thus making it possible to excavate by generating a considerably higher torque even in the case of hard soil foundation and extremely deep excavation, and by making the anchor body fit to a considerable pulling resistance force required when using the anchor body remaining straddled.
In order to attain the foregoing object, the following are applied for the present invention:
The present invention relates to the mechanical ground anchor including an anchor body having a plurality of parts forming a cylindrical shape linked with the outer side of a core material. The parts are linked for opening and closing in the horizontal direction through a slide mechanism and a drive part, such as a jack, mounted on the core material for the purpose of opening and/or closing the anchor body.
The slide mechanism may include a slide piece receiving frame mounted inside the core material crosswise to its radial direction and a slide piece fastened on each part of the anchor body, with the slide piece being inserted into the slide piece receiving frame.
The slide mechanism of the present invention may alternatively include the slide piece formed so as to extend in the radial direction of the core material by fixing its inner end to the core material and by providing an equal number of slide piece receiving frames fastened to the anchor body at the opposite side of the core material, the slide piece receiving frame being inserted over the slide piece.
The slide mechanism of the present invention may further include a mechanism for mounting a boring bit on the tip of the core material and a screw on the outer circumferential edge of each anchor body.
REFERENCES:
patent: 2637527 (1953-05-01), Andrews
patent: 3225843 (1965-12-01), Ortloff et al.
patent: 3962837 (1976-06-01), Sero
patent: 4160613 (1979-07-01), Stanwick
patent: 4314615 (1982-02-01), Sodder et al.
patent: 4342527 (1982-08-01), White
patent: 4547106 (1985-10-01), Lipsker
patent: 5660504 (1997-08-01), Reinert
patent: 51-103611 (1976-09-01), None
patent: 52-46013 (1977-04-01), None
patent: 63-194023 (1988-08-01), None
patent: 4-13496 (1989-05-01), None
patent: 3-32637 (1991-03-01), None
Bagnell David
Greenblum & Bernstein P.L.C.
Kabushikigaisha Jiban Shikenjo
Lagman Frederick L.
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