JPH0413445Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] This invention is a hole in which an enlarged diameter part called an undercut is cut in the deep part of the hole, and in particular, a locking step is provided on the opening side of the enlarged diameter part. The present invention relates to an embedded screw structure embedded in a provided hole.

[Prior art]

A screw body is often embedded and fixed in a surface to be fixed, for example, a solidified concrete surface (hereinafter referred to as a concrete surface), and other articles are attached via the embedded screw.

In order to improve the pull-out strength of embedded screws, the applicant has developed a drilling device that cuts an enlarged diameter portion at the deep end of a straight drill hole drilled into a concrete surface. Various embedded screws suitable for being embedded in a hole having an enlarged diameter portion have also been proposed.

In the above-mentioned hole having an enlarged diameter part, the enlarged diameter part generally has a diameter that gradually increases from the hole opening toward the back of the hole, and as an embedded screw embedded in this type of hole, For example, a foundation bolt with an overhanging jaw that forms a tapered surface that gradually expands in diameter downward at the lower end is integrally connected, and a slit cut into the lower end from the lower end surface allows multiple expandable pieces. and a cylindrical deployment sleeve with a shape formed therein, the deployment sleeve is inserted into the hole along with the foundation bolt, and each deployment piece of the deployment sleeve corresponds to the expanded diameter part,
There is a device in which each deployable piece is moved onto the tapered surface of the overhanging jaw under pressure applied to the expansion sleeve, expanded, and then fixed in a pinched state between the wall surface of the enlarged diameter part and the overhanging jaw. .

[The problem that the idea aims to solve]

By the way, as another form of the enlarged diameter part, a drilling technique for a hole having an enlarged diameter part with a hooking step has been established, in which a hooking step is provided on the hole opening side of the enlarged diameter section. If a structure is adopted in which each deployable piece of the deployable sleeve is deployed in a superimposed state on the tapered surface of the overhanging jaw as described above in the hole having the enlarged diameter portion with the latching step, the deployable pieces The outer surface is in line contact with the corner of the latching step and is crimped to receive the external load, so the original usefulness of the enlarged diameter part with the latching step cannot be fully demonstrated. .

This invention has been made in view of the above-mentioned points, and an object thereof is to provide an embedded screw structure suitable for being embedded in a hole having an enlarged diameter portion with a locking step.

[Means to solve the problem]

The gist of this invention to achieve the above purpose is that an enlarged diameter part is cut at the back of the hole, and a locking step is provided on the opening side of the enlarged diameter part. A foundation bolt with an integrally connected protruding jaw with a tapered surface whose diameter gradually expands downward at the lower end, and a plurality of slits cut from the upper end surface leaving a thin connecting part at the lower end. A deployable piece is formed, and a cylindrical deployable sleeve is loosely inserted into the base bolt, and the lower end of the deployable sleeve is moved downward on the tapered surface of the overhanging jaw within the hole to connect the thin wall. The embedded screw structure is characterized in that the upper end of each deployable piece is extended and the upper end of each expandable piece is latched and crimped onto the latching step surface of the enlarged diameter hole.

[Effect]

A foundation bolt with a deployment sleeve loosely inserted is inserted into a hole drilled in the concrete surface that has an expanded diameter section with a locking step, and a separately prepared bolt is inserted with the deployment sleeve aligned with the expanded diameter section. When the deployable sleeve is hammered through a cylindrical driving rod, the thin joint at the lower end of the deployable sleeve expands on the tapered surface of the overhanging jaw, and the deployable sleeve expands its outer diameter to flatten the tapered surface. As it moves downward, the lower end of the driving rod is press-fitted between the deploying sleeve and the foundation bolt, pushing the upper end of each deployable piece outward, and the deploying sleeve as a whole becomes cylindrical in the shape of a truncated cone. It deforms so that the upper end of the unfolding piece faces the latching step surface of the enlarged diameter part.

After this, insert the embedded screw body, which has a female thread for connection at the base and a female thread for mounting at the top, into the hole.
When the foundation bolt is screwed into the connecting female thread and fixed, and the internal thread for mounting of the embedded screw body is used to attach various items to the concrete surface, the deployable sleeve is used to hook the protruding jaw and the enlarged diameter part. It is clamped and latched between the stepped surfaces to absorb external loads.

〔Example〕

Hereinafter, embodiments of this invention will be described based on the drawings.

FIG. 1 is an exploded perspective view of this invention, and FIG. 2 is a longitudinal sectional view showing how it is used.

In the figure, reference numeral 1 denotes a foundation bolt having a male thread 2, which is integrally connected with an overhanging jaw 3 having a tapered surface 3a whose diameter gradually increases downwardly at the lower end. It is set so that it can be inserted loosely into hole A drilled in the hole A.

Reference numeral 4 denotes a cylindrical deployable sleeve, which is loosely inserted into the foundation bolt 1 and has a plurality of deployable pieces 6 formed by slits cut from the upper end surface, leaving a thin connecting portion 5 at the lower end. And its height is hole A
It is determined in accordance with the enlarged diameter portion B that is cut.

Note that both upper and lower end surfaces of this deployment sleeve 4 are preferably formed into tapered surfaces whose diameters expand outward.

Reference numeral 7 denotes an embedded screw body, which has a center hole, has a connecting female screw 8 screwed into the male screw 2 of the foundation bolt 1 at its base, and a mounting female screw 9 at its upper part, and
A driver engagement groove 10 is formed on the upper end surface.

Note that the two female screws 8 and 9 of this embedded screw body 7
The pitch of the upper female mounting thread 9 is preferably larger.

Furthermore, although the embodiment shows a configuration in which the embedded screw body 7 is provided with a female mounting screw 9, this may be a male screw.

Figures 3a to 3d are explanatory diagrams showing the construction procedure of this invention.

The enforcement procedure will be explained below with reference to this figure.

Figure 3 a: Insert the foundation bolt 1 into the hole A drilled in the concrete surface, which has an enlarged diameter part B with a locking step C.

Further, the expansion sleeve 4 is loosely inserted into the base bolt 1 so that the lower end thereof is placed on the tapered surface 3a of the overhanging jaw 3 so as to correspond to the enlarged diameter portion B.

Fig. 3 b When a separately prepared driving rod D, which is cylindrical and has approximately the same diameter as the deployment sleeve 4, is inserted into the hole, and its lower end is applied to the upper end of the deployment sleeve 4 and hammered, the overhanging jaw is The thin connecting portion 5 of the deployment sleeve 4 expands on the tapered surface 3, and the deployment sleeve 4 moves downward on the tapered surface 3a while increasing its outer diameter, and the lower end of the driving rod D
The expansion sleeve 4 is press-fitted between each expansion piece 6 and the base bolt 1, and the upper end of the expansion piece 6 is pushed outward, and the expansion sleeve 4 is deformed into a truncated conical cylinder shape as a whole.

Figure 3 c Insert the embedded screw body 7 into the hole and use an appropriate screwdriver to insert its tip into the driver engagement groove 1.
0 and screwed in, the male thread 2 of the foundation bolt 1 is screwed into the female connection thread 8 of the embedded screw body 7, and finally the foundation bolt 1 and the embedded screw body 7 are fixed together.

Figure 3 d When the embedded screw body 7 is fixed in the hole A and the structure F etc. is attached to the concrete surface using the mounting bolt E using the female mounting screw 9 on the upper side, each expansion occurs in the enlarged diameter part B. The upper end of the piece 6 is uniformly crimped and latched to the surface of the latching step C to maintain a strong fixed relationship.

〔effect〕

As explained above, according to the embedded screw structure of this invention, the embedded screw body for attaching a structure etc. to a concrete surface and the deployable sleeve formed with a plurality of deployable pieces are configured separately. Inside the hole, the deploying sleeve substantially expands its outer diameter and expands its upper end outwards to transform the overall shape into a truncated conical cylinder, which is connected to the overhanging jaw of the foundation bolt. Since it is crimped and latched between the latching step surface of the enlarged diameter part and receives external loads, the pull-out strength of the embedded screw is greatly increased and stability is improved.

In addition, the embedded screw body is screwed into the bolt body of the foundation bolt using a screwdriver after each deployment piece of the deployment sleeve is deployed in the hole, so no force is applied to the embedded screw body, and it is secure and secure. It is an excellent idea that allows for strong fixation, good workability, and can be applied in many fields.

[Brief explanation of the drawing]

FIG. 1 is an exploded perspective view of this invention, FIG. 2 is a vertical sectional view showing how it is used, and FIGS. 3 a to 3 d are explanatory diagrams of the implementation procedure. 1...Foundation bolt, 2...Male thread, 3...Protruding jaw, 4...Deployment sleeve, 5...Thin wall connection part,
6... Deployment piece, 7... Embedded screw body, 8... Female thread for connection, 9... Female thread for mounting, 10... Driver engagement groove, A... Hole, B... Expanded diameter part, C...
Latch step, D...driver rod, E...installation screw,
F...Structure.

Claims (1)

[Scope of utility model registration request] An enlarged diameter part is cut at the back of the hole, and the diameter enlarged part is embedded in a hole with a locking step provided on the hole opening side, and a tapered surface whose diameter gradually increases downward is formed at the lower end. A cylindrical piece that is loosely inserted into the foundation bolt is formed by forming a plurality of expandable pieces by forming a foundation bolt with integrally connected overhanging jaws, and slits cut from the upper end surface leaving a thin connection part at the lower end. the lower end of the deployable sleeve is moved downwardly on the tapered surface of the overhanging jaw within the hole to extend the thin connecting portion, and the upper end of each deployable piece is expanded outward. The embedded screw structure is characterized in that the upper end of the expandable piece is latched and crimped onto the latching step surface of the enlarged diameter hole.