JP2582038B2 - Plastic insert - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to plastic inserts which are embedded in concrete products for various purposes, such as for lifting concrete products and for connecting concrete products.

[0002]

2. Description of the Related Art FIGS. 6 to 8 show a conventional general plastic insert 10. FIG. The insert 10 has a thread 12 on the inner periphery of a cylindrical main body 11, a punching-resistant plate 13 protruding in a flange shape at the rear end, which resists a pull-out force, and a punching-resistant plate 13 on its front side. A fin-shaped reinforcing plate 14 is formed along the axial direction so as to integrate the cylindrical body 11 with the fin.

[0003]

Plastic inserts can be manufactured in various shapes at low cost and relatively easily, and have the advantage that concrete is not destroyed by rust. It has the disadvantage of being weak. However, in recent years, plastic inserts having greater strength, such as using plastic inserts for lifting concrete products, have been desired.

FIG. 8 shows a conventional plastic insert 10 embedded in concrete C, a bolt (not shown) screwed into the insert 10, and a test of what kind of breakage occurs by pulling it from the concrete surface. It is explanatory drawing of a pull-out test. In many cases, as shown in the figure, the insert 10 breaks and the concrete has a crack 1
5 occurs. That is, the punching-resistant plate 13 and the reinforcing plate 14 of the insert 10 remain in the concrete, and only the tubular main body 11 is torn off. This is because inserts are weaker than concrete.

When a pull-out test as described above is performed on a metal insert, the insert does not break, but the concrete always breaks, and the broken concrete lump comes out together with the insert. This is because the metal insert is stronger than the concrete, so that a higher pull-out strength is obtained than when the insert is broken as described above.

An object of the present invention is to provide a plastic insert which is less likely to be broken when a pulling force acts on the insert and which can obtain a higher pulling strength.

[0007]

According to the present invention, a thread is formed on an inner peripheral surface of a cylindrical body having a front end opened and a rear end closed, and a punching-resistant plate is formed on the outer peripheral surface near the rear end in the form of a flange. An insert having a plurality of reinforcing plates formed on the front side and the rear side of the punching-resistant plate along the axial direction so as to integrate the punching-resistant plate and the cylindrical body. A plastic insert characterized in that a thread on the peripheral surface is formed at least deeper than a front end of the punching-resistant plate, and a front surface of the punching-resistant plate is formed as an inclined surface inclined outward.

[0008]

In the plastic insert of the present invention, since the thread on the inner peripheral surface is formed at least deeper than the front end of the punch-resistant plate, the pulling force is transmitted to the punch-resistant plate reliably through the screw. In the conventional insert, as shown in FIG. 7, since the thread is formed only before the punching-resistant plate, the pull-out force is not reliably transmitted to the punching-resistant plate, and the punching-resistant plate is torn off into the concrete. It will remain.

Further, since a plurality of reinforcing plates are formed not only on the front side but also on the rear side of the punching-resistant plate along the axial direction so as to integrate the punching-resistant plate and the cylindrical main body, the reinforcing plate is provided. The blanking plate and the tubular main body are more firmly integrated, and there is no possibility of tearing.

Since the front surface of the punching-resistant plate has an inclined surface inclined outward, when the pulling force is applied to the insert, the direction of the force of the front surface of the punching-resistant plate pushing the concrete is indicated by an arrow A in FIG. As shown, it slopes outward rather than parallel to the axis of the insert. When the concrete breaks, it breaks into a substantially conical shape. As described above, since the direction of the force (arrow A) inclines outward, the angle b of the break surface at this time decreases. That is, the area of the concrete fracture surface is increased, and it is possible to withstand a larger pulling force. This was of little significance since conventional plastic inserts were weaker than concrete, but in the inserts of the present invention, when a pull-out force was applied, it was particularly resistant to the action of the reinforcing plate on the rear side. This prevents the punched plate from being deformed, and the front surface of the punched plate reliably transmits the force to the concrete, and the concrete can be broken.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings showing embodiments. FIG. 1 is a side view of a plastic insert 1 of the present invention, FIG. 2 is a front view of the insert 1, and FIG.
FIG. 4 is a rear view of the insert 1, FIG. 4 is a cross-sectional view of the insert 1, and FIG.

The insert 1 is made of polypropylene mixed with glass fiber, and has a thread 6 formed on the inner peripheral surface of the cylindrical main body 2 having a front end opened and a rear end closed, and an outer peripheral surface provided with a near-rear end near the rear end. The punched plate 3 is formed to protrude in a flange shape, and four reinforcing plates 4 are provided on the front side of the punched-resistant plate 3 and eight reinforcing plates 5 are provided on the rear side. It is formed in a fin shape along the axial direction. The thread 6 on the inner peripheral surface is
As shown in FIG. 4, it is formed deeper than the front end (line B) of the punching-resistant plate 3. As shown in FIG. 1, the front surface of the anti-extraction plate 3 is an inclined surface inclined outward by an angle a. In this embodiment, a is about 15 degrees.

As shown in FIG. 5, the insert 1 was embedded in concrete C and subjected to a pull-out test.
The concrete broke at the fracture surface D, and the concrete mass pulled out together with the insert 1. The angle b of the fracture surface is about 18
Degree. The pull-out strength was about 1.3 times that of the conventional plastic insert.

[0014]

The plastic insert of the present invention
Can resist large pulling force. When concrete breaks, the area of the fracture surface increases, and the allowable pulling force becomes extremely large. Therefore, it can be sufficiently used for applications requiring a large pull-out resistance, such as lifting concrete products.

[Brief description of the drawings]

FIG. 1 is a side view of an insert 1. FIG.

FIG. 2 is a front view of the insert 1. FIG.

FIG. 3 is a rear view of the insert 1. FIG.

FIG. 4 is a cross-sectional view of the insert 1.

FIG. 5 is an explanatory diagram of a pull-out test of the insert 1.

6 is a perspective view of the insert 10. FIG.

7 is a sectional view of the insert 10. FIG.

FIG. 8 is an explanatory diagram of a pull-out test of the insert 10.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Insert 2 Cylindrical main body 3 Removable board 4 Reinforcement board 5 Reinforcement board 6 Thread 10 Insert 11 Cylindrical main body 12 Thread 13 Extrusion-resistant board 14 Reinforcement board 15 Crack

Claims (1)

(57) [Claims] 1. A thread is formed on an inner peripheral surface of a cylindrical main body having a front end opened and a rear end closed, and a punching-resistant plate is formed on the outer peripheral surface near the rear end in a flange shape. An insert in which a plurality of reinforcing plates are formed on the front side and the rear side of the plate in a fin shape along the axial direction so as to integrate the punching-resistant plate and the cylindrical main body, and at least a thread on the inner peripheral surface is resistant. A plastic insert characterized by being formed deeper than the front end of the punched plate and having an inclined surface with the front surface of the punched-out plate inclined outward.