JPH0885948A - Spacer for anchor tightening member and its manufacture - Google Patents

Abstract

PURPOSE: To enhance the easiness in execution of works by forming a plastic supporting part having a plurality of axially directed notches at the circumference tying cylindrical gripping parts at the two ends, and curving the supporting part outward in radial direction from the central part in the axial direction. CONSTITUTION: Slits 6 are provided in cylindrical gripping parts 2, 3 so that a spacer 1 can easily be fitted on the tip of a tightening member such as an irregularly shaped PC steel rod 9. When the spacer 1 is to be moved on the steel rod 9 for fitting or location, a plurality of notches 7 are furnished at the two ends in addition to the slits 6, and thereby the operation is facilitated and risk of damaging the plating layer does not exist, which is likely with a conventional spacer made of metal. This spacer 1 made of synthetic resin is free from corrosion and sustain satisfactorily the practical use in terms of strength. To manufacture spacer 1, a construction of a thermoplastic resin such as polyethylene is formed wherein the supporting part is not curved, and compression is made from the ends toward the center in the condition that the supporting part 5 is heated, and the part 5 is curved outward. This enhances the anti-corrosiveness and the easiness in mounting works and allows low-cost manufacturing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spacer for a fixed long portion of a permanent anchor used for preventing landslide on a slope and for stabilizing a bridge pier.

[0002]

2. Description of the Related Art As a spacer used for a fixed length portion of a PC tension member in a permanent anchor body, a lantern-shaped spacer made of steel plate is already known. This is, as shown in FIGS. 3A and 3B, cylindrical grips 2 and 3 at both ends,
It comprises a support portion 5 having a cut 4 in the axial direction of the circumference connecting both tubular portions. Since the support portions 5 are curved outwardly and bulged, they are called lanterns. Reference numeral 17 in the drawing denotes a welded portion of the support portion 5 to the cylindrical grip portions 2 and 3.

[0003]

The above-mentioned lantern shape has sufficient strength and sufficient support for the tension material, but the manufacturing thereof requires punching, bending, welding of a steel sheet, and labor and cost. . In addition, when using it, it has the drawback that it easily corrodes due to infiltration of groundwater, etc. If you apply a coating process such as plating to prevent this, it will be more troublesome and the coating layer will be easily scratched during installation. It is hard to say that scratches cause corrosion.

[0004]

SUMMARY OF THE INVENTION The present invention is intended to solve the above-mentioned problems, and has a first feature that the spacer is formed of a synthetic resin such as polyethylene to eliminate the fear of corrosion. A second feature of the present invention is that a slit is provided in the cylindrical grip portion of the spacer or a slit is added to improve the operability of attaching and positioning the spacer.

Another feature of the present invention is that when the spacer is manufactured from a thermoplastic synthetic resin, the outward bulge of the support portion is formed by compressing the support portion from the outside in the axial direction under heating. Is. The details of the invention as well as other features are described by way of examples.

[0006]

1A and 1B are a front view and a sectional view taken along line I-I of a spacer 1 in an embodiment. In the figure,
Reference numerals 2 and 3 denote cylindrical gripping portions provided at both ends, and the gripping portions 2 and 3 are connected by a supporting portion 5 having a plurality of axial cuts 4 in the circumference, and are integrally formed by polyethylene. Has been formed.

The outer diameter of the cylindrical grip portions 2 and 3 is 48 mm,
The wall thickness including the supporting portion 5 is 4 mm. And the support part 5 is
Initially, there was no bending and the length between the ends of the cylindrical grips 2 and 3 was 3
The length of 280 mm was 280 mm, which was 00 mm and was compressed to the inside from the outside in the axial direction while being heated to the softening temperature of the resin or above, and was expanded to the outside in the radial direction from the central part.
It is formed by shrinking to.

When the spacer 1 having the above-mentioned structure was used for the permanent anchor shown in FIG. 2, it was found that it did not corrode and was sufficiently practical for strength. The following processing was performed before actually mounting on the anchor. As a result, the operability of anchor installation work, such as the insertion of tension materials, has been improved.

On both or one of the cylindrical grips 2, 3,
If the slit 6 of about 0.5 mm is provided, it is easy to insert the spacer into the tip portion of the deformed PC steel rod 9 having a diameter of 36 mm to be inserted into the drilled hole 8 of the rock as shown in FIG. You can also open it and cover it from the side.

Further, in order to move on the steel rod 9 for the above-mentioned fitting and positioning, in addition to the slit 6, a plurality of notches 7 are provided from both ends to facilitate the operation. In addition, even if the spacer hits the hole wall or the steel rod during the operation, there is no fear of scratching the plating and losing the anticorrosion property as in the conventional case.

The spacer having the above structure is formed by extruding a thermoplastic synthetic resin such as polyethylene or polyvinyl chloride as described above so that the supporting portion is not curved, and then the supporting portion is heated. The cost can be reduced because it can be easily manufactured by pressing the lower part relatively to the center and compressing it to swell the center part of the support part outward and cooling it in a curved state.

FIG. 2 is a conceptual side sectional view showing the structure of the permanent anchor formed in the drilled hole 8 formed in the rock mass.
The inside of the drilled hole 8 is divided into a head portion 10 at the entrance, a free length portion 11 at the center, and a fixing length portion 12 at the back. Deformed PC inserted in the drilled hole 8
The steel rod 9 is fixed by being filled with cement grout or the like while being supported by the spacer 1 in the fixing length portion 12.

The head 10 is provided with a nut 13, a cap 14, a joint sheath 15 and the like and is tensioned and fixed. Reference numeral 16 is a protective tube that wraps the steel rod 9. In the embodiment, the deformed PC steel rod 9 is used as the tension material, but other tension materials such as a synthetic resin-coated PC steel stranded wire may be used. When this synthetic resin coating is used, there is also an effect that the coating is less likely to be damaged by the spacer.

Further, as for the production of the spacer, the method of pressing and heating and compressing using a thermoplastic synthetic resin as in the above-mentioned embodiment is easy and economical, but if necessary, a thermosetting resin is used. It may be manufactured by another manufacturing method.

[0015]

Since the spacer of the present invention is made of a synthetic resin, it has good anticorrosion properties and, due to its constitution, has good operability in attaching to the tension member. During the same operation, spacer and PC
There are few defects caused by scratching the steel material. Manufacturing is easy and the manufacturing cost is reduced.

[Brief description of drawings]

FIG. 1A is a front view of an embodiment of the present invention, and B is a sectional view taken along line I-I of A. FIG.

FIG. 2 is a conceptual view from the side cross-section showing the structure of a permanent anchor.

FIG. 3A is a front view of a conventional spacer, and B is I- of A.
FIG.

[Explanation of symbols]

 1 Spacer 2, 3 Cylindrical gripping part 4 Cut of support part 5 Support part 6 Cut 7 Cut 7 Cut of rock 8 Deformed PC steel rod 10 Head 11 Free length part 12 Fixing length part 13 Nut 14 Cap 15 Joint sheath 16 Protective tube 17 Weld

Claims (4)

[Claims] 1. Cylindrical grips at both ends made of synthetic resin,
An anchor tension characterized in that a supporting portion having a plurality of axial cuts is formed on the circumference connecting the gripping portions, and the supporting portion is curved outward in the radial direction from the central portion in the axial direction. Spacer for material. 2. The spacer according to claim 1, wherein the cylindrical grip portion is provided with a slit in the axial direction. 3. The spacer according to claim 1, wherein one or more notches are provided on the outer end side of the cylindrical grip portion. 4. A thermoplastic synthetic resin is used to form a cylindrical grip portion at both ends and a support portion having a plurality of axial cuts on the circumference connecting the grip portions, and then the support portion of the formed body is fixed. A method for manufacturing a spacer for an anchor tension member, which comprises compressing from the outside in the axial direction in a heated state to bend and deform the support portion from the center in the axial direction to the outside in the radial direction.