JP2000274413A - Anchor bolt and its installation structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an anchor bolt and its installation structure capable of expanding multiple expanded pieces with less power and easily adjusting the main bolt position. SOLUTION: The anchor bolt is comprised of a main bolt 2 equipped with a bulging part 5 whose diameter expands toward the bolt tip, and a cylindrical expandable sleeve 3 fitted around the main bolt 2. The expandable sleeve 3 is divided into several expanded pieces 8 arranged in a circumferencial direction by longitudinal cracks 7 extending from the tip side facing to the bulging part 5 in an axial direction and each top end of these expanded pieces 8 is mutually connected via a first narrow connecting part 9. Each expanded piece 8 described above is further divided into two expanded pieces 8a and 8b arranged in an axial direction by a transversal crack 10 extending in a circumferencial direction and these expanded pieces 8a and 8b is mutually connected via a second narrow connecting part 11. Starting with the tip, the anchor bolt 1 is inserted into a hole with a specific part broadening toward the bottom of the hole so that the bulging part 5 of the main bolt 2 can loosely fit into the broadening part of the hole. The expanded pieces 8 are pressed into the gap between the bulging part 5 and the broadening part of the hole to prevent the main bolt 2 from coming off.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anchor bolt used for fixing structures such as equipment, equipment, fences, columns, and the like to concrete, rock, and the like, and a planting structure thereof.

[0002]

2. Description of the Related Art An anchor bolt for expanding an expansion sleeve in a hole drilled in concrete, rock or the like is well known. In general, this type of anchor bolt includes a bolt main body having a protruding portion that expands in a tapered shape toward the distal end side, and a tubular expanding sleeve that is externally fitted to the bolt main body. At the distal end of the expanding sleeve, a plurality of expanding pieces are formed which are separated by longitudinally extending grooves. Then, by moving the expanding sleeve toward the tip of the bolt body in the hole, the expanding piece is pushed and expanded by the wedge action of the overhanging portion and pressed against the hole wall, so that the outer surface of the expanding piece and the hole wall are in contact with each other. Withdrawal drag is obtained by frictional resistance due to contact. When such anchor bolts are planted, the holes drilled in concrete, rock or the like are usually straight holes having an almost constant inner diameter from the opening to the bottom of the hole. Also, when expanding the expanding piece in the hole, usually, a driving pipe of an appropriate length is externally fitted to the bolt body, inserted into the hole, and one end protruding outside from the hole of the pipe. Is hit with a hammer, so that the expanding sleeve is driven toward the bottom of the hole via the other end of the pipe, so that the expanding piece of the expanding sleeve rides on the protrusion of the bolt body.

[0003]

As described above, in the conventional anchor bolt, the frictional resistance between the hole wall of the straight hole and the expanding piece is used as the pull-out resistance. It is necessary to maintain the pressure-bonded state between the opening and the hole wall, so that the expanding piece has a sufficient strength and is supported by the expanding sleeve. Therefore, since the expanding piece does not easily expand at the time of planting, a large amount of labor is required for the expanding sleeve driving work using a hammer and a driving pipe. There was a problem that it could not be done. Further, since a great deal of labor is required, it is extremely difficult to plant anchor bolts on a downward surface such as a ceiling, which requires a driving operation in an unreasonable posture. Furthermore, it is extremely difficult to plant anchor bolts underwater, because the speed of swinging down the hammer is reduced due to the resistance of water.

Further, since the bolt body is firmly fixed after the expanding sleeve is driven, the position of the bolt body cannot be finely adjusted in accordance with the anchor bolt insertion hole of the structure. There was also a problem that the installation of the structure was inconvenient.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and an anchor bolt and an implant thereof capable of expanding an expanding piece with a small force and easily adjusting the position of a bolt body. The purpose is to provide an installation structure.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a bolt body having an overhang which tapers toward the distal end, and a cylindrical body fitted to the bolt body. In the anchor bolt comprising the expansion sleeve, the expansion sleeve is divided into a plurality of expansion pieces arranged in a circumferential direction by a vertical groove extending in an axial direction from a front end surface facing the overhanging portion. The base ends of the expanding pieces are connected to each other via a first narrow connecting portion.

[0007] In the above construction, each expanding piece of the expanding sleeve is divided into a plurality of split expanding pieces arranged in the axial direction by transversely extending grooves, and these split expanding pieces are divided into a plurality of pieces. They are mutually connected via two narrow connecting portions.

Further, in the anchor bolt planting structure according to the present invention, a hole having an enlarged portion tapering toward the bottom of the hole is formed in concrete, rock, or the like, and the anchor having the above-described structure is formed in the hole. Insert the bolt from the tip end so that the projecting part of the bolt body faces the hole, and push the expanding piece of the expanding sleeve into the gap between the projecting part and the hole to prevent the bolt body from coming off. It is like that.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An anchor bolt according to one embodiment of the present invention will be described below with reference to FIGS. An anchor bolt indicated by reference numeral 1 as a whole in the figure is composed of a bolt main body 2 and a substantially cylindrical expansion sleeve 3 fitted to the bolt main body 2. In this embodiment, both the bolt body 2 and the expanding sleeve 3 are made of steel.

A male screw portion 4 for fixing a structure is formed on the base end side of the bolt body 2. At the tip of the bolt body 2, a truncated conical overhang 5 is formed that tapers toward the tip. Male thread 4
An intermediate portion 6 having a circular cross-section is formed between the protrusion 5 and the overhang portion 5.

The expanding sleeve 3 has an inner diameter slightly larger than the outer diameter of a portion of the bolt body 2 excluding the overhanging portion 5, and can freely move in the axial direction over the male screw portion 4 and the intermediate portion 6. It has become. The expanding sleeve 3 is cut from the front end surface facing the overhang portion 5 of the bolt body 2,
Vertical split grooves 7 are formed extending in the axial direction to near the base end face opposite to the tip end face. A total of four vertical grooves 7 are arranged at equal intervals in the circumferential direction. The expanding sleeve 3 is divided by the vertical grooves 7 into four expanding pieces 8 arranged in the circumferential direction. The axial length of the expanding piece 8 is set substantially equal to the axial length of the projecting portion 5 of the bolt body 2.

The portion remaining without being cut off between the terminal end of each vertical groove 7 and the base end surface of the expanding sleeve 3 is a first narrow connecting portion for connecting the base ends of the expanding pieces 8 to each other. It is 9. By connecting the base ends of the expanding pieces 8 via the first narrow connecting parts 9, the base ends of the expanding pieces 8 and the first narrow connecting parts 9 are circumferentially connected. A continuous annular portion is formed. The annular portion holds the expanding sleeve 3 in a cylindrical shape, and each expanding piece 8 has a base end supported by the first narrow connecting portion 9. It is to be done.

A circumferentially extending transverse groove 10 is formed substantially at the center of the expanding sleeve 3 in the axial direction so as to intersect with the vertical dividing groove 7. The piece 8 is divided into a divided enlarged piece 8a (base end side) and a divided enlarged piece 8b (distal end side) arranged in the axial direction with the horizontal dividing groove 10 interposed therebetween. Then, these divided expanding pieces 8a, 8
b are connected to each other via the second narrow connecting portion 11 to form the expanding piece 8. As is clear from the figure, the second narrow connecting portion 11 connects the butted ends of the divided expanding pieces 8a and 8b while straddling the horizontal split groove 10, so that the horizontal split groove 10 is It is divided at the narrow connecting portion 11 of FIG.

Next, a mode of use of the anchor bolt 1 configured as described above will be described with reference to FIG. When planting this anchor bolt 1, concrete,
In the fixed body 12 such as a rock, a hole-expanding portion 1 that expands in a tapered shape.
A hole 13 having 3a at the bottom of the hole is formed. The method of forming the hole 13 is arbitrary, but after forming a straight hole with a drill, the bottom of the straight hole is formed by using a hole expanding tool proposed in Japanese Patent Application No. 10-294773 filed by the present applicant. A hole may be formed in the hole. The inner diameter of the hole 13 excluding the widened portion 13a is slightly larger than the maximum outer diameter of the projecting portion 5 of the bolt body 2. Also,
The height from the hole bottom to the upper end of the widened portion 13a is
Is substantially equal to the distance from the tip end surface to the boundary between the overhang portion 5 and the intermediate portion 6. Further, the spread angle of the widened portion 13a is made substantially equal to the spread angle of the projecting portion 5 of the bolt body 2.

When the hole 13 is formed, the anchor bolt 1 is inserted into the hole 13 from the front end side, and the projecting portion 5 of the bolt body 2 is made to face the widened portion 13a. Then, a separately prepared pipe (the outer diameter and the inner diameter are almost equal to the expanding sleeve 3,
A pipe having a sufficient length: not shown) is externally fitted to the bolt body 2 and inserted into the hole 13, and one end of the pipe protruding out of the hole 13 is vertically moved by hand.
The base end surface of the expanding sleeve 3 is pressed toward the hole bottom with the other end surface of the pipe. Then, the expanding piece 8 is moved from the tip side to the overhang portion 5.
Is pushed into the gap between the hole and the hole 13a, and the split and widened piece 8b and then the split and widened piece 8b ride on the overhang portion 5 and are sequentially expanded. When the expanding sleeve 3 is sufficiently pushed in, the pipe is pulled out, and a nut 15 is screwed into the male screw portion 4 via the structure 14 (see FIG. 3). As a result, a force in the direction of pulling the bolt body 2 out of the hole 13 is applied, and the divided expanding pieces 8a, 8b are pressed against the inner peripheral wall of the hole 13a, so that the bolt body 2 is locked in the hole 13,
The structure 14 is fixed.

In the above description, the gap between the hole 13 and the bolt body 2 is bent at a position corresponding to the boundary between the projecting portion 5 and the intermediate portion 6 of the bolt body 2.
In addition to the fact that the expanding pieces 8 are interconnected by the first narrow connecting portion 9, each expanding piece 8 is divided into split expanding pieces 8 a, 8.
Since b is connected by the second narrow connecting portion 11, the bent portion of the gap can easily pass. In other words, first, when the split expansion piece 8b runs on the overhang portion 5, the second narrow connecting portion 11 bends outward, and only the split expansion piece 8b is allowed to expand (at this stage, The split expanding piece 8a does not expand). Next, when the divided expanding piece 8a also rides on the overhang portion 5, the second narrow connecting portion 11 returns to the original straight state, and the first narrow connecting portion 11a returns to the first straight state.
Are bent so as to allow the split expanding piece 8a to expand.

Here, the first narrow connecting portion 9 and the second narrow connecting portion 11 can be bent with a small force because they are formed extremely narrower than the expanding piece 8. The split expanding pieces 8a and 8b are about half the length of the expanding piece 8 in the axial direction, and are short, so that they do not get caught when passing through a bent portion of the gap. . Therefore, since the expanding piece 8 can be expanded with an extremely small force as compared with the conventional one, there is no need to hit one end of the driving pipe with a hammer as in the conventional case, and the pipe or a similar expanding pipe is used. It is possible to expand the expanding piece 8 simply by operating the opening sleeve pressing tool from the outside of the hole 13 by hand and pressing or appropriately hitting the base end surface of the expanding sleeve 3. Therefore, the labor required for the installation work of the anchor bolt can be reduced, and the work can be performed even by a person with weak power. Since the work is easy, anchor bolts can be planted on a downward surface such as a ceiling and anchor bolts can be planted underwater, which has been extremely difficult in the past. In addition, when it is necessary to deepen the hole for planting, and if the body of the anchor bolt is lengthened, it has been particularly difficult to expand the expanding piece conventionally due to the elasticity of the driving pipe. This is not the case with the bolt 1, and the expansion piece 8 can be expanded at a deep position away from the surface of the fixed body 12 to lock the anchor bolt body 2.

Also, unlike a conventional anchor bolt in which the frictional resistance between the hole wall and the expanding piece is used as a pull-out drag, in this anchor bolt 1, the projecting portion 5 is provided on the expanding portion 13 a via the expanding piece 8. The pulling resistance is obtained by locking.
Therefore, although the supporting strength of the expanding piece 8 is low due to the presence of the first and second narrow connecting portions 9 and 11, the pulling resistance is not insufficient.

Further, in the anchor bolt 1, even after the expanding piece 8 is expanded, it is not until the nut 15 is screwed and the expanding piece 8 and the inner peripheral wall of the hole 13a are crimped. Since there is a slight gap (rack) between the overhang portion 5, the expanding piece 8, and the inner peripheral wall of the hole portion 13a, the bolt body 2
The position of the male screw portion 4 can be adjusted in the radial direction by moving the male screw in the runout direction. Therefore, the structure 14
Also, the effect that the bolt holes 14a for anchors can be easily fitted into the male screw portion 4 is also achieved.

The curvature of the inner peripheral wall of the expanding sleeve 3 in the direction crossing the anchor bolt 1 (ie, the curvature of the inner surface of the expanding piece 8) is constant from the base end of the expanding sleeve 3 to the distal end. In the case where the expanding piece 8 is expanded, the portion where the diameter at the tip end side of the overhanging portion 5 is large is large.
A gap may be formed between the inner surface and the outer peripheral surface of the overhang portion 5 due to a difference in curvature, and the locking state of the overhang portion 5 may become unstable. This is shown in FIGS. 4 and 5. This can be dealt with by adopting such a configuration. That is, as shown in FIG. 4, at the position near the base end surface of the expanding sleeve 3, the curvature of the inner surface of the expanding piece 8 is close to the curvature of the outer peripheral surface of the intermediate portion 6 of the bolt body 2 (see FIG. 4B). ), Expanding sleeve 3
The expanding sleeve 3 is formed in such a shape that the radius of curvature of the inner surface of the expanding piece 8 gradually increases as approaching the distal end face (see FIGS. 4C and 4D). This allows
The curvature of the inner surface of the expanding piece 8 at each position in the axial direction is set to be substantially equal to the curvature of the outer peripheral surface of the projecting portion 5 at each axial position facing the expanded piece 8 in the expanded state. . With this configuration, when the expanding piece 8 is expanded, as shown in FIG. 5, the inner surface of the expanding piece 8 and the outer peripheral surface of the overhang portion 5 are in close contact with each other at any position in the axial direction. Since there is no gap between them, the locking state of the protruding portion 5 to the widened portion 13a is further stabilized, and the anchor bolt installation strength can be improved.

Needless to say, the present invention is not limited by the above embodiments. For example, in the above description, the overhanging portion 5 is provided at the tip of the bolt body 2, but the axial position at which the overhanging portion 5 is provided is arbitrary. If the widened portion 13a of the hole 13 where the anchor bolt is to be planted is formed at a position spaced upward from the bottom of the hole, the bolt 13 is extended closer to the middle than the tip of the bolt body 2 in accordance with this. It is preferable to provide the protrusion 5.

In the above, the first narrow connecting portion 9 and the second narrow connecting portion 11 are configured to be easily bent when the expanding piece 8 is expanded. The configuration may be such that the second narrow connecting portion is easily broken and cut with the expansion of the expanding piece. Further, in the above, each expansion piece 8 is divided into two divided expansion pieces 8a and 8b.
However, the expansion piece may be composed of three or more divided expansion pieces connected and integrated with each other at the second narrow connecting portion.

[0023]

As described above, according to the present invention,
The projecting part of the bolt body is made to face the tapered hole of the hole formed in concrete, rock, etc., and the expanding piece of the expanding sleeve is pushed into the gap between the projecting part and the hole. Thus, the expanding piece can be easily expanded with a small force, so that the labor required for the installation work of the anchor bolt can be reduced as compared with the related art. This allows even people with weak powers to work, and it is also possible to plant anchor bolts on the downward surface such as the ceiling or underwater, and furthermore, to anchor the bolts deeper in the planting holes. Various effects such as easy locking of the bolt body can be obtained. In addition, even after the expansion piece is expanded, the position of the bolt body can be adjusted before the expansion piece and the inner peripheral wall of the hole are crimped, so that the structure can be easily attached. The effect of becoming

Further, in the case where each expanding piece of the expanding sleeve is constituted by a plurality of divided expanding pieces connected via the second narrow connecting portion, the gap between the hole and the bolt body is bent. Even when passing through the location, the expanding piece does not get caught and does not cause any resistance, so that the expanding piece can be expanded with a smaller force.

[Brief description of the drawings]

FIG. 1 is a side view of an anchor bolt according to an embodiment of the present invention.

FIG. 2 is a perspective view of an expansion sleeve.

FIG. 3 is a cross-sectional side view illustrating the expanding structure of the anchor bolt according to the embodiment of the present invention, showing the expanding sleeve in a cross section along the line AA of FIG. 1;

4A and 4B are diagrams illustrating a cross-sectional shape of the expanding sleeve, wherein FIG. 4B is along a line BB in FIG. 1, FIG. 4C is along a line CC in FIG. FIG. 4D is a cross-sectional end view at each position along the line DD in FIG. 1.

5A and 5B are views for explaining the cross-sectional shapes of the expanding sleeve and the overhanging portion, and FIG. 5E is a view along the line EE in FIG.
(F) is along the line FF in FIG. 3, and (g) is G in FIG.
It is an end view of the cutting part in each position along the -G line.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Anchor bolt 2 Bolt main body 3 Expanding sleeve 5 Overhanging part 7 Vertical split groove 8 Expanding piece 8a, 8b Dividing expanding piece 9 First narrow connecting part 10 Horizontal split groove 11 Second narrow connecting part 13 Hole 13a Expanding Hole

Claims (3)

[Claims] 1. An anchor bolt comprising a bolt main body having a projecting portion tapered toward the distal end and having a projecting portion, and a tubular expanding sleeve externally fitted to the bolt main body. A vertical split groove extending in the axial direction from the distal end face facing the overhanging portion divides the plurality of expanded pieces arranged in the circumferential direction, and the base ends of these expanded pieces form the first narrow connecting portion. An anchor bolt characterized in that it is connected to each other through a bolt. 2. Each of the expanding pieces of the expanding sleeve is divided into a plurality of split expanding pieces that are arranged in the axial direction by transversely extending grooves extending in the circumferential direction, and these split expanding pieces are connected to a second narrow connection. The anchor bolt according to claim 1, wherein the anchor bolts are connected to each other via a portion. 3. A hole having an enlarged portion tapering toward the bottom of the hole is formed in concrete, rock or the like, and the anchor bolt according to claim 1 or 2 is inserted into the hole from the tip side. An anchor bolt characterized in that the projecting portion of the bolt body faces the widened portion and the widening piece of the widening sleeve is pushed into the gap between the protruding portion and the widened portion to prevent the bolt body from coming off. Planting structure.