JPH0228004B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fixing tool suitable for use by being embedded in a thermosetting synthetic resin.

When a screw hole is formed in a member made of a synthetic resin molded product and a bolt or the like is screwed into the member, the tension and
When subjected to external forces such as torsion, vibration, etc., or when a bolt or the like is repeatedly attached and detached, the screw hole becomes deformed or destroyed and becomes unusable. Therefore, a nut-shaped metal fastener has been proposed that can be embedded in a member to stably fix a bolt or the like and can withstand repeated attachment and detachment.
If this fixing device is embedded during component molding,
It is very troublesome to have to equip the molding die with a fixing tool each time, and it is more advantageous in terms of work to form a hole for embedding and fixing at the time of molding the member and embed the fixing tool therein. The fixing tool usually has knurling or other irregularities on the outer circumferential surface so that it bites into the member and is fixed with sufficient strength, and is embedded in a hole in a member made of a molded thermoplastic synthetic resin. In some cases, the periphery of the hole can be softened by applying ultrasonic vibration to generate frictional heat, or electric resistance heat can be generated by passing an electric current through the hole, causing the unevenness to bite into each other. In the case of a member made of a synthetic resin molded article, it does not melt even when heated, so it is not possible to heat the periphery of the hole to soften it and cause the fluidized synthetic resin to bite into each other when it cools and solidifies again.

The purpose of the present invention is to solve these problems and provide a fixing device that can be firmly and stably embedded into a member made of thermosetting synthetic resin. The main body is formed into a truncated conical shape with a large diameter, and a plug body having a diameter approximately equal to the diameter of a hole for embedding and fixing is provided protruding from the tip of the main body, On the other hand, it is characterized in that it has a structure in which a large number of diagonal uneven stripes are provided, and at least one annular groove is provided so that the uneven strip is divided into at least two parts between the distal end and the base end.

Embodiments of the present invention will be described below with reference to the drawings. The main body 1 has a truncated conical shape with a slightly larger diameter than the base end. On the outer peripheral surface of the main body 1, a large number of concave and convex lines 2 oblique with respect to the axial direction are formed. and an annular groove 3, and a plug 4 having a diameter equal to or slightly smaller than the diameter of the hole to be embedded and fixed is provided in front of the tip of the main body 1 with a neck 5 having a smaller diameter than that. It is.

The concavo-convex strips 2 are inclined at an angle of about 45 degrees with respect to the axis and have a triangular cross section, with the distal end surface and the apex of the convex portion being particularly sharp.

In the embodiment shown in Figs. 1 and 2, two grooves 3, 3 are provided to divide the concavo-convex strip 2 into approximately three equal parts between the distal end and the proximal end, and a female screw hole is provided which penetrates from the proximal end surface to the distal end surface. 6
In the embodiment shown in FIG. 3, one groove 3 is provided to divide the uneven strip 2 into approximately two halves between the distal end and the proximal end, and the male threaded rod 7 is integrated at the proximal end. It is formed in a protruding manner, and in addition to the male threaded rod 7, an electrical connection terminal, a square shaft, etc. may be provided in a protruding manner depending on the purpose.

Figures 4, 5, and 6 show the first,
This figure shows an example of the work order for embedding and fixing the fixing device according to the embodiment shown in FIG. Insert the tool from the tip. The hole 12 is formed to have a diameter approximately equal to the diameter of the stopper 4 and a depth approximately equal to the entire length of the fastener. is placed on the center line of Next, the proximal end surface of this fixing tool is pressed into the fixing device by hitting it with a hammer or pressurizing it with a press. First, the distal end surface of the main body 1 is pushed into the hole 12 with the entrance end widened, and then is moved toward the bottom of the hole while sequentially expanding, and at this time, the uneven strips 2 on the outer circumferential surface bite into the hole wall and cut the flesh of the member 20, and the fixing tool is moved while being rotated. Since the main body 1 is made to gradually become smaller in diameter toward the base end, the hole 12, which is widened by the distal end, contracts due to the elasticity of the material and comes into close contact with the main body 1. When the stopper 4 reaches the bottom of the hole and is stopped, the uneven strip 2 bites into the hole wall of the hole 12, the recess is filled with synthetic resin, and the annular groove 3 is filled with the cut synthetic resin.

In addition, the fixing tool of the present invention is made of carbon steel, stainless steel,
Made from a relatively hard metal such as zinc.

As described above, the present invention provides a large number of uneven stripes diagonal to the axial direction on the outer circumferential surface of the main body, so that holes having the same diameter or smaller diameter than the concave portion at the proximal end of the main body of the uneven stripes can be formed. By driving or embedding and press-fitting, the uneven strips can cut the flesh of the member and completely bite into the hole wall. In particular, according to the present invention, the main body has a truncated conical shape with a large diameter at the tip;
During implantation, the distal end receives the greatest resistance, but since the proximal end has a small diameter, it does not experience much resistance due to its hardness as a whole, and can be implanted with normal force. When the embedding is completed, the deep part of the hole is expanded to the maximum extent, and the restoring force of the synthetic resin allows it to firmly adhere to the main body, and the uneven stripes are provided diagonally, making it resistant to tension. This creates an extremely large resistance force and eliminates the fear of it being pulled out. In addition, since the hole has a small expansion at the entrance end, as shown in Figure 4, the hole is provided in a boss with a drawing taper, so even if the entrance end of the hole is the thinnest wall, there is no risk of cracking, twisting or Even if vibrations are applied, the parts will not be destroyed. In addition, the annular groove allows cuttings of the synthetic resin to enter, allowing for smooth embedding into the hole, and the plug at the tip allows the fixing tool to be fitted onto the center line of the hole. The concavo-convex stripes on the main body prevent the fixing tool from moving in the radial direction when cutting begins, and allow the fixing tool to be completely bitten around the entire circumference.

[Brief explanation of drawings]

Fig. 1 is a front view showing an embodiment of the present invention, Fig. 2 is a bottom view thereof, Fig. 3 is a front view showing a different embodiment, and Figs. 4, 5, and 6 are embedding and fixing operations. FIG. 2 is an explanatory diagram showing the order. 1... Main body, 2... Uneven strip, 3... Groove, 4...
Plug body.

Claims (1)

[Scope of Claims] 1. A main body having a truncated conical shape with a distal end having a larger diameter than a base end, and a main body having a diameter approximately equal to the diameter of a hole to be implanted and fixed, and provided protruding from the distal end of the main body. The main body has a large number of grooves and grooves on the outer peripheral surface thereof diagonally with respect to the main axis, and the grooves and grooves are divided into at least two parts between a distal end and a base end. A fastening device characterized in that it has at least one annular groove. 2. The fixing device according to claim 1, wherein a female screw hole is provided passing through from the proximal end surface to the distal end surface. 3. The fixing tool according to claim 1, wherein a male threaded rod is provided protruding from the base end of the main body.