JP2001020924A - Blind rivet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a peel type blind rivet wherein the cutting of the opening at one end of a body section by means of the cutting edge section formed in a lower face section of a mandrel head section and expansion in a radial direction are surely and uniformly performed, providing stable and specified fastening force. SOLUTION: This peel type blind rivet comprises a rivet body 2 having a flange-like head section 4 at one end of a cylindrical body section 3, and a mandrel 5 having a head section 6 expanded at one end thereof and to be insertedly incorporated into the body section 3. In this case, the mandrel is provided with a plurality of cutting edges 8 radially extending in the lower face part 7 of the head 6. In addition, the blind rivet is formed with a plurality of split leg pieces which are widely opened in radial directions while cutting the opening 14 of the other end of the body section 3 by the cutting edges 8. The opening 14 of the other end of the body section 3 is provided with a plurality of cutting guiding grooves 15 corresponding to the cutting edges 8, and with the cutting edges 8 positioned in the cutting guiding grooves 15, the mandrel 5 is incorporated in the rivet body 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blind rivet, and more particularly to an improvement of a so-called peel type blind rivet suitable for fastening a soft material.

[0002]

2. Description of the Related Art A peel type blind rivet of this type is provided with a plurality of cutting blades extending radially on a lower surface portion of a mandrel head, and a rivet body having a flange-shaped head at one end of a cylindrical body. By pulling the mandrel inserted through the body, a plurality of split leg pieces that are opened in large petals in the radial direction while cutting the other end opening of the body with the cutting blade are formed, The leg piece and the flange-shaped head of the rivet main body are fastened to each other (see, for example, JP-A-10-274220 and JP-A-5-36115).

[0003]

However, in a structure in which a cutting blade is only provided on the lower surface portion of the mandrel head as in the above-mentioned conventional blind rivet, the shape or hardness of the cutting blade is microscopic. Due to variations and microscopic variations such as perpendicularity of the end face of the opening of the rivet body, surface roughness, unevenness in hardness, etc., the cutting edge portion makes the cut into the other end opening of the body non-uniform. However, there has been a problem that only a part of the cut plurality of divided leg pieces is largely opened in the radial direction, and not all the divided leg pieces are uniformly opened in the radial direction. In some cases, the cutting resistance is increased due to the offset of the cutting action of the cutting blade, and the mandrel may be torn off in a state where the opening at the other end of the body is insufficiently cut. For this reason, the conventional blind rivet of this type has a drawback that the variation in fastening force is large and cannot be put to practical use.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and the cutting of the opening at the other end of the body by a cutting blade provided on the lower surface of the mandrel head and the expansion in the radial direction,
It is an object of the present invention to provide a peel-type blind rivet that is reliably and uniformly performed and that can obtain a stable predetermined fastening force.

[0005]

To achieve the above object, the present invention provides a rivet body having a flange-shaped head at one end of a cylindrical body, and an enlarged head at one end of a mandrel body. A plurality of cutting blades extending radially on a lower surface portion of the mandrel head, wherein the mandrel is inserted into the body and assembled. A peel-type blind rivet in which a plurality of split leg pieces are formed by cutting the other end opening of the body and opening in a large petal shape in the radial direction, wherein the cutting blade is provided in the other end opening of the body. A plurality of cutting guide grooves are provided corresponding to the portions, and the mandrel is assembled to the rivet main body with the cutting blade positioned in the cutting guide grooves.

The mandrel is secured to the body by a bulge formed on the side surface of the mandrel at the time of forging the tearing constriction provided near the head, and the mandrel is attached to the rivet body. It is assembled in a retaining state.

[0007] The retaining means for the mandrel assembled to the rivet body may be provided on a shaft portion of the mandrel projecting from the rivet body.

In the blind rivet of the present invention, the mandrel is pulled in a state where the cutting blade provided on the mandrel head is engaged with the cutting guide groove provided at the other end opening of the body of the rivet body. The opening of the other end is easily and reliably cut by the cutting blade, and the cut plurality of divided leg pieces are uniformly and largely opened in the radial direction.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a blind rivet 1 according to the present invention. The blind rivet 1 has a rivet body 2 having a flange-shaped head 4 at one end of a cylindrical body 3 and an enlarged head 6 at one end of a mandrel body, and is inserted through the body 3 of the rivet body 2. And a mandrel 5 that is assembled. The rivet body 2 and the mandrel 5 are both made of stainless steel.

The mandrel head 6 has a diameter substantially equal to the outer diameter of the body 3 of the rivet body 2 and a lower surface portion 7 is formed in an upwardly expanding truncated cone shape, and extends radially to the lower surface portion 7. Four cutting blades 8 are provided. It is preferable that the cutting blade 8 be a ridge protruding in a V-shape as shown in the figure. In addition, in order to form a tearing constriction 9 in the vicinity of the head 6 of the mandrel 5, as shown in FIGS. The bulging portions 12 are formed by opposing each other, and the bulging portions 12 serving as retaining means described later are formed by the forging.

The body 3 of the rivet body 2 has a through hole 13 through which the mandrel 5 is inserted.
In the (opening opposite to the flange-shaped head 4), four cutting guide grooves 15 corresponding to the cutting blade 8 of the mandrel 5 are provided. The cutting guide groove 15 is formed in a V-shaped groove in which the V-shaped cutting blade 8 is engaged and engaged. FIG.
As is best shown in the figure, inside the opening 14 there is provided a conical guide surface 16 which inclines inwardly, corresponding to the conical seating surface 7 of the mandrel head 6, so that each cutting The guide groove 15 extends from the outer peripheral surface to the conical guide surface 16.

Then, the mandrel 5 is inserted through the opening 14 into the body 3 so that each of the cutting blades 8 has a corresponding cutting guide groove 15.
As shown in FIG. 1, the bulging portion 12 of the mandrel 5 is brought into close contact with the inner wall surface of the through hole 13 of the body 3, and the mandrel 5 is prevented from coming off the rivet body 2 as shown in FIG. Assembled. As a means for preventing the mandrel 5 from coming off, as shown in FIG. May be mounted so as to be in close contact with the flange-shaped head 4. In this case, only the V-shaped groove 10 is provided in the mandrel 5 to form the tear-off constriction 9 and the bulging portion 12 does not need to be provided.
The use of such a stopper 17 is advantageous in that the mandrel 5 does not unexpectedly come off as compared with the retaining means provided by the bulging portion 12.

FIG. 6 shows an example in which a relatively soft refractory board 21 is attached to a support member 20 using the blind rivet 1 of the present invention configured as described above.
The body 3 of the rivet body 2 is inserted from the head 6 side of the mandrel 5 into the bottomed fitting hole 23 provided in the fireproof board 21 through the mounting hole 22 of the support member 20, and the flange-shaped head 4 is attached to the support member 20. When the mandrel head 6 is in contact with the
When the mandrel 5 is pulled so as to be drawn into the
As the blade enters the through hole 13, the cutting blade 8 is pressed into the cutting guide groove 15, and the opening 14 of the body 3 is inserted into the cutting guide groove 15.
, And is radially expanded to form four divided leg pieces 14a. At this time, each cutting edge 8
Are correctly engaged with the corresponding cutting guide grooves 15, so that the opening 14 is reliably and uniformly cut,
The cut four leg pieces 14a are radially expanded in a petal shape by the lower surface portion 7 of the mandrel head 6, and are press-fitted into the refractory board 21 to cooperate with the flange-shaped head 4. Then, the refractory board 21 is attached and fixed to the support member 20 (see FIG. 7). As described above, the four divided leg pieces 14a are uniformly and largely opened in a petal shape in the radial direction, so that a predetermined fastening force can be stably obtained. When the mandrel 5 is further tensioned, the mandrel 5 is torn off and cut at the constriction 9, and only the head 6 side remains pressed into the body 3.

FIGS. 8 and 9 show another embodiment of the present invention. In this embodiment, the mandrel 5 has the external thread 2
5 is provided, and a small-diameter shaft portion 26 having a diameter smaller than the root diameter of the male screw portion 25 is provided at the inner end of the male screw portion 25.
A square shaft 27 is provided at the outer end of the mandrel 5.
After the respective cutting blades 8 of the mandrel 5 inserted into the body 3 of the rivet body 2 are positioned so as to engage with the corresponding cutting guide grooves 15, the mandrel 5 is screwed to the male thread 25 by the nut 28. The rivet main body 2 is assembled in a retaining state.

In use, as shown in FIG. 9, a rotary cylinder shaft 31 for rotating the nut 28 and a lock for engaging the square shaft portion 27 to prevent the mandrel 5 from rotating together with the nut 28. A special tool 30 having a shaft 32 and a nut 2
The mandrel 5 is pulled by tightening the mandrel 8, and the mandrel 5 does not tear off, and the setting of the rivet is completed when the nut 28 idles on the small diameter shaft portion 26.

[0017]

As described above, according to the present invention,
A plurality of cutting guide grooves corresponding to a plurality of radially extending cutting blade portions provided on the lower surface portion of the mandrel head are provided at the other end opening of the body portion of the rivet main body, and the cutting guide portions are provided in the cutting guide grooves. Since the mandrel is assembled to the rivet body in the positioned state, when tension is applied to the mandrel during a fastening operation, cutting and opening in the radial direction of the opening of the body by the cutting blade portion are performed. It is possible to obtain an effect that the operation is performed reliably and uniformly and a stable predetermined fastening force is obtained.

[Brief description of the drawings]

FIG. 1 is a partially cutaway front view of a blind rivet according to the present invention.

FIG. 2 is an enlarged cross-sectional view of the mandrel taken along line 2-2 of FIG.

FIG. 3 is an enlarged sectional view taken along line 3-3 in FIG.

FIG. 4 is an enlarged plan view showing an opening of a body of the rivet body.

FIG. 5 is a partially cutaway front view showing another embodiment of the blind rivet according to the present invention.

FIG. 6 is a vertical sectional front view showing an example of use of a blind rivet according to the present invention.

FIG. 7 is a plan view taken along the line 7-7 in FIG. 6;

FIG. 8 is a vertical sectional front view of an essential part showing another embodiment of a blind rivet according to the present invention.

FIG. 9 is a vertical sectional front view showing a use state of the blind rivet.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 blind rivet 2 rivet main body 3 torso 4 flanged head 5 mandrel 6 mandrel head 7 bottom surface 8 cutting blade 9 torn narrowing portion 12 bulging portion 13 through hole 14 other end opening 15 cutting guide groove 16 cone Guide surface 17 Stop fitting

Claims (4)

[Claims] 1. A rivet body having a flange-shaped head at one end of a cylindrical body, and a mandrel having an enlarged head at one end of a mandrel body and being inserted into and assembled to the body, A plurality of cutting blades extending radially are provided on a lower surface portion of the mandrel head, and the other end opening of the body is cut by the cutting blade by pulling the mandrel main body, and the cutting edge is enlarged in a radial direction. A peel type blind rivet in which a plurality of divided leg pieces that open in a petal shape are formed, wherein a plurality of cutting guide grooves corresponding to the cutting blade portions are provided in the other end opening of the body, and the cutting guide is provided. A blind rivet, wherein the mandrel is assembled to the rivet body with the cutting blade portion positioned in a groove. 2. The rivet main body, wherein the mandrel is locked to the body by a bulge formed on a side surface of the mandrel at the time of forging molding of a torn narrow portion provided near the head of the mandrel. The blind rivet according to claim 1, wherein the blind rivet is assembled to the blind rivet. 3. A blind rivet according to claim 1, wherein said mandrel assembled to said rivet main body is provided with a retaining means at a shaft portion protruding from said rivet main body. 4. The lower surface portion of the mandrel head is formed in an upwardly expanding frustoconical shape, and the cutting edge portion is provided on the lower surface portion. The blind rivet according to claim 1, 2 or 3, wherein a conical guide surface inclined toward is provided, and the cutting guide groove extends to the conical guide surface.