JPH064085Y2 - Expanded anchor for contact - Google Patents

Description

[Detailed Description of the Invention] Industrial field of application The present invention relates to an expansion anchor for concrete in which the tip of the anchor body is expanded outward by the wedge action of the plug, which is drilled in concrete or rock. It is used to fix building construction members, machines, etc. by expanding and fixing in the mounting holes.

2. Description of the Related Art As shown in Figs. The side is defined as an inclined hole 23 having a smaller diameter toward the tip surface, and the plug 25 having the conical portion 26 having a smaller diameter toward the tip surface is inserted into the hole from the base end side and press-fitted into the inclined hole 23. A widened anchor for concrete in which the tip end portion divided by the split groove 24 extending in the longitudinal direction of the anchor body 21 is widened is widely known.

As shown in FIG. 3, the anchor main body 21 is provided with an uneven ridge 27 extending in the circumferential direction on the outer peripheral surface of the front end thereof.
It is known from Japanese Patent Publication No. 88, etc., and the one provided with a mesh-shaped knurl 28 as shown in FIG. 4 is Japanese Patent Publication No. 50-661.
It is known from Japanese Patent Publication No. 8 and the like, and the one in which the outer peripheral surface of the tip portion of the anchor body 21 is made smooth as shown in FIG.
It is known from Japanese Patent Publication No. 55-166909.

Problems to be solved by the invention The one shown in Fig. 3 is provided with uneven ridges in order to improve the pull-out strength by satisfactorily sticking concrete to the hole wall when it is expanded. Since the ridges and ridges must be formed by cutting, it is not only the top surface of the manufacturing process, but also thick and thin parts alternately appear in the longitudinal direction at the part that is bent and expanded outward of the tip part. Therefore, there is a problem in that the rigidity deteriorates and the expected pull-out strength cannot be obtained by destroying the concrete when it goes into the hole wall of the concrete.

The one shown in FIG. 4 is provided with a knurl for the same purpose as the one shown in FIG. 3, but since this knurl has a mesh shape and must be formed by a cutting process as well, it is not only the manufacturing upper surface inversion, However, there is a problem that it is difficult to obtain sufficient pull-out strength because the surface layer portion of the hole wall is finely divided and broken into meshes when it is bitten into the hole wall of concrete.

In FIG. 5, in order to avoid the above-mentioned drawbacks, the outer peripheral surface of the front end portion of the anchor body is made smooth, but the pulling strength is obtained only by the frictional resistance due to the simple contact with the hole wall. Therefore, there is a problem that it cannot withstand a large tensile force.

Therefore, the present invention was devised in order to solve these conventional problems and provide an expansion anchor for concrete that can obtain a large pulling strength.

MEANS FOR SOLVING THE PROBLEMS The present invention has an anchor body having an inclined hole having a small diameter toward the tip surface and a split groove extending in the longitudinal direction at a tip portion, and a conical portion having a diameter decreasing toward the tip surface. And a plug that press-fits into the inclined hole and expands the tip portion of the anchor body, and the anchor body is provided with a knurl extending in the longitudinal direction on the outer peripheral surface of the tip portion. It was a means to solve the problem.

Embodiments The present invention will be described with reference to the embodiments shown in FIGS. 1 and 2. An anchor body 1 is formed in a cylindrical shape having a hole 2 penetrating therethrough in the front and rear direction, and a collar that extends slightly outward to the base end. 3, the base end side of the hole 2 is a female screw hole 4, and the tip end side is a conical inclined hole 5 having a diameter gradually decreasing toward the tip end surface. In addition, a plurality of split grooves 6 extending in the longitudinal direction, generally four, are provided at equal intervals in the circumferential direction at the tip of the anchor body 1 and are divided so as to be expandable, and from the tip end face toward the base end. A knurl (flat knurl) 7 extending an appropriate length in the longitudinal direction is provided on the outer peripheral surface.

The plug 8 is formed by a base portion 9 that is fitted into the hole 2 almost densely and a conical portion 10 that has a diameter that gradually decreases toward the front end surface thereof.

The plug 8 is inserted into the hole 2 of the anchor body 1 from the base end side, and the conical portion 10 is in contact with the base of the inclined hole 5, and is inserted into a mounting hole formed in concrete or rock, and the plug 8 is driven. The tip portion of the anchor body 1 expands by being inserted into the inclined hole 5 and bites and is fixed to the hole wall. The knurling 7 bites into the hole wall to increase the contact area.

Effect of the Invention The anchor body of the present invention can be easily manufactured without cutting, because the inclined hole and the knurling can be formed at once by fitting the punch into the hole by press fitting the punch into the hole. In addition, the knurl provided in the expanding portion has a uniform cross-sectional area in the longitudinal direction and has excellent rigidity because it extends in the longitudinal direction of the anchor body. Moreover, since the knurl penetrates the hole wall in the longitudinal direction, it makes contact with a wide area. In addition, concrete is less likely to be destroyed when it is bitten, and a large frictional resistance is generated, so that a stable fixing force can be obtained.

Here, the product of the present invention and the conventional product have a length of 40 mm and an outer diameter.
A 12 mm anchor body was provided with tilted holes of the same size, plugs of the same size were press-fitted, and a pull-out strength test was conducted on mounting holes of different diameters. That is, A is the product of the present invention, B is FIG. 3, C is FIG. 4 and D.
Shows the conventional product shown in FIG. 5, and the knurls A and C are triangular in cross section with a vertical angle of 90 degrees and a height of 0.5 mm. A has 28 peaks and C has a pitch of 0.73 mm. The knurls were provided in the range of 10 mm in the axial direction from the tip end, extending in the direction inclined by 45 degrees with respect to the direction. The concavo-convex stripes of B were provided in a range of 12 mm in the crest, 11.4 mm in the trough, 3 in the trough and 12 mm in the axial direction from the tip. As a result of testing these three mounting holes each having the same diameter and obtaining the average value of the respective withdrawal loads, it was found that the device of the present invention withstands a larger withdrawal load than the conventional one.

[Brief description of drawings]

FIG. 1 is a front view of an embodiment of the present invention, FIG. 2 is a vertical sectional view of a plug inserted from an anchor body, and FIGS. 3, 4, and 5 are partially cut front views of a conventional product. FIG. 6 and FIG. 6 are views showing test results of pulling strength. 1 ... Anchor body, 5 ... Inclined hole, 6 ... Split groove, 7 ...
Knurled, 8 ... Plug, 10 ... Conical part,

Claims (1)

[Scope of utility model registration request] 1. An anchor body having an inclined hole having a small diameter toward the tip end surface and a split groove extending in the longitudinal direction at the tip end, and a conical portion having a small diameter toward the tip end surface and press-fit into the inclined hole. The expansion anchor for concrete, characterized in that it comprises a plug for expanding the tip of the anchor body, and the anchor body is provided with a knurl extending in the longitudinal direction on the outer peripheral surface of the tip.