JPH0377735A - Manufacture of expanded sleeve for clamping/fastening tool - Google Patents

Abstract

PURPOSE:To simplify working and to prevent the wastefulness of material by providing plural radial grooves on a flat material, deep-drawing the material into a bottomed tube body, redrawing the front part into a smaller diameter, punching the bottom of the front part and threading its inside. CONSTITUTION:Six grooves 2 are cut into a circular flat plate 1 at equal intervals in the peripheral direction and then a 1st tube body 3 having a bottom is made by a die and a punch. Then, a 2nd tube body 4 smaller in diameter and drawn more deeply than the tube body 3 is made and an inclined flange 5 is formed so that the open edge part of the tube body is expanded outward and upward. Further, a 3rd tube body 6 smaller in diameter and drawn more deeply than the 2nd tube body 4 is made and a square flange 7 is formed. Then, a 4th tube body 8 smaller in diameter and drawn more deeply than the 3rd tube body 6 is made and the front part 9 of the tube body 8 is drawn into a smaller diameter, the tube body 8 and its front part 9 are drawn and finished into a 5th tube body 10 and its front part 11 to form a head part 12 having a regular hexagonal flat surface and a downward projecting edge 12a on the outward peripheral edge. A female thread 14 is provided on the inside of the front part 11 of small diameter to form a nut 15.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention provides a fastener that expands on the back side of a member, and more specifically, a fastener having a head at the proximal end, a nut at the distal end, and a fastener between them. This invention relates to a method for manufacturing an expansion sleeve of a fastening device, in which a fastening method comprises a combination of an expansion sleeve having a plurality of grooves extending in the axial direction, and a threaded rod inserted into the expansion sleeve from the proximal end side and screwed onto a nut. It is something.

(Prior Art) A fixing tool has been proposed that allows construction materials and equipment to be fixed from only the front side without the need for workers to enter the back side of the component or insert tools. There is.

An expansion sleeve having a head at the proximal end, a nut at the distal end, and a plurality of grooves extending in the axial direction between them; and an expansion sleeve that is inserted into the expansion sleeve from the proximal end and screwed onto the nut. A fixing device is one of the fastening tools that is used in combination with a threaded rod, which is fitted into the pilot hole of the member and causes the widened part between the grooves and the nut to protrude to the back side, and the expansion sleeve is rotated. The nut is moved toward the proximal end by fixing the head and turning the screw so that the expanded portion is bent outward and expanded into a petal shape, working with the head to loosen the member. It is a device that clamps and tightens (for example, Utility Model Publication No. 29-3006, No. 5)
6-48965).

The expansion sleeve generally has the shape shown in FIG. 16, and is made by cutting a round bar of material into a predetermined length, forming a rectangular head 101 at one end by forging, and then forming a through hole 102 with a drill. Then, a female thread 103 is provided at the tip of the through hole 102 by thread processing to form a nut 104, and a plurality of grooves 105 extending in the axial direction are formed in a portion between the head 101 and the nut 104 by cutting. The portion between them is configured as an expanded portion 106.

That is, not only is the process complicated and laborious because several completely different machining processes have to be performed, but also a large amount of cutting waste is generated especially when forming the through hole 102, resulting in a lot of wasted material. .

(Problems to be Solved by the Invention) The present invention attempts to solve the problems that the conventional manufacturing method for expansion sleeves is not only complicated and troublesome to process, but also wastes a lot of material. It is an object of the present invention to provide a manufacturing method that is simple, easy to process, and causes almost no wastage of materials.

(Means for Solving the Problems) In order to solve the above problems, the present invention firstly provides a plurality of grooves radially in a flat plate of material by cutting, and secondly, forms the outer peripheral edge of the flat plate by deep drawing. The cylindrical body is machined into a cylinder with a bottom, and the tip is re-drawn to form a small diameter.Thirdly, the bottom of the tip is removed by punching, and a female thread is formed on the inner surface of the small diameter tip by threading. This measure was taken.

The flat plate material used in the present invention is made of a metal such as mild steel or stainless steel that can be deep drawn and has the mechanical strength to be used as a fastening tool. In addition, the head of the expansion sleeve is not only used to clamp and fix the member, but also to prevent rotation when turning the screw rod to bend and bulge the expansion part, so it is normally square-shaped, and the flat plate is square-shaped. A regular polygon, such as a regular hexagon, corresponding to the head of a person may be used, but a circular shape is also acceptable.

The grooves are arranged radially at equal intervals in the circumferential direction, except for the outer periphery, which is the part that is fitted into the head and the pilot hole of the member, and the center part, which is the small diameter tip and the short part on the base end. There are a plurality of them, and they are made by cutting with a knife-like cutting tool. Therefore, the grooves are linear and are provided without generating cutting chips, and the portion between them becomes an expanded portion.

Next, deep drawing is carried out using a well-known device equipped with a die and a punch. This can be done by repeatedly redrawing to finally reach the required depth. Furthermore, re-drawing to form a small-diameter tip is performed using a well-known device equipped with a die and a punch, but in this case as well, the process of sequentially shaping the tip into a predetermined shape is performed using punches with different diameters and tip shapes. It may be applied.

The outer periphery of the flat plate that will become the head can be bent into the desired shape after deep drawing or redrawing, or if deep drawing is performed by redrawing, it can be bent a little at each step. Shape into the required regular polygon at any time, such as by making a die or punch so that it will have a predetermined shape when shaping and forming the small diameter portion at the tip.

Additionally, the bottom of the tip is removed by shear punching using well known die and punch equipment, so that material wastage is essentially only at the bottom. In addition, female threads are usually formed by cutting with a tap,
Forming by rolling is advantageous because no cutting waste is generated.

Incidentally, in order to make the wall thickness of the expansion sleeve uniform, if necessary, ironing may be performed in a separate process. Finally, the surface may be plated or painted to prevent rust.

(Function) Radial grooves are cut into a flat plate, the area between them is used as an expanded part, and then a cylindrical body is formed by deep drawing, leaving an outer periphery that will become the head. Through this process, grooves extend parallel to each other in the axial direction to form a cylindrical body, and the bottom of the small-diameter tip formed by redrawing is punched out to provide a female thread to form a nut.

Grooves can be formed all at once from one direction.

Further, the processing of the cylinder forming the enlarged portion that bends and bulges, the processing of the small-diameter tip portion forming the nut, the removal of the bottom, and the processing of the internal thread are all performed by plastic working means, and the steps are simple.

(Example) The present invention will be described in detail with reference to the drawings.

First, the required wall thickness, made of mild steel or stainless steel;
A circular flat plate 1 having a diameter is prepared, and six grooves 2 are provided by cutting at equal intervals in the circumferential direction except for the outer peripheral edge and the center (FIG. 1). The grooves 2 are formed into stripes by placing the flat plate 1 on a table and inserting six knife-shaped cutting tools into it all at once, and moving the cutting tools all at once or sequentially in the radial direction as necessary. It is formed.

Second, deep drawing is performed by re-drawing using the apparatus shown in Figure 5.10.11.12. That is, a flat plate 1 provided with grooves 2 is placed on a die 21 of the apparatus shown in FIG. 10, and its outer peripheral edge is pressed down with a wrinkle presser 24.

The punch 23 is driven to push the entire flat plate 1 into the gap between the die hole 22 and the punch 23 to form the first cylindrical body 3 with a bottom (FIG. 2). Next, the first cylindrical body 3 is placed on the die 25 of the apparatus shown in FIG.
is driven to form a second cylinder 4 which has a diameter of A1 and is drawn deeper than the first cylinder 3, and the opening end edge thereof is aligned with the inclined surface 26a of the entrance of the die hole 26 and the slope of the punch 27. A diagonal flange 5 that expands outward and upwardly is formed between the shoulder portion 27a (FIG. 3), and a die 28 of the apparatus shown in FIG.
The second cylindrical body 4 is placed concentrically with the die hole 29a and the punch 30 is driven to create a third cylindrical body 6 which has a smaller diameter than the second cylindrical body 4 and is deeply drawn. A right-angled flange 7 is formed by sandwiching the diagonal flange 5 between the right-angled shoulder portion 30a and the upper surface of the die 28 (FIG. 4).

When the above-mentioned deep drawing is completed, re-drawing is carried out to form a small diameter tip in this process using the apparatus shown in FIGS. 13 and 14. That is, the die 31 of the apparatus shown in Place the third cylinder 6 concentrically with the die hole 32 and punch 33.
to form a fourth cylindrical body 8 that is smaller in diameter than the third cylindrical body 6 and drawn deeper, and also to form a small diameter hole 32a at the bottom of the die hole 32.

The tip 9 of the cylinder 8 is squeezed to a small diameter by the small diameter part 33a at the tip of the punch 33 (FIG. 5), and the fourth cylinder 8 is inserted into the die hole 35 of the device shown in FIG. The punch 36 is driven concentrically and the cylinder 8 and tip 9 are squeezed to form a fifth cylinder 10 and its tip 11 of predetermined dimensions.
A and the downward groove 36a of the stepped portion of the punch 36 sandwich the right-angled flange 7, forming a regular hexagonal head 12 having a downward protruding edge 12a on the outer periphery (FIG. 6).

Third, the bottom of the tip is removed to form a female thread on the inner surface of the small diameter tip 11. That is, the die 3 of the apparatus shown in FIG.
The fifth cylindrical body 10 and its tip 11 are fitted into the die hole 38 of No. 7, and the punch 39 is driven to remove the bottom by shear punching (FIG. 7). Then, a female thread 14 is formed on the inner surface of the tip portion 11 by cutting or rolling.

8 and 9 show the expansion sleeve made by the above process, in which the portion corresponding to the fifth cylindrical body 10 extends in the axial direction over almost the entire length except for the portion that is fitted into the pilot hole of the member. The six extending grooves 2 extend parallel to each other at equal intervals in the circumferential direction, and the portion between them forms an expanded portion 13.

In addition, the small diameter tip 11 provided with the female thread 14 is connected to the nut 1.
5 is formed.

In addition, this expansion sleeve is inserted from the proximal end side with a threaded rod and screwed onto the nut 15, and then fitted from the front side into a pilot hole provided in two overlapping plate-like members from the front side. By fixing the nut 15 so that it does not rotate and turning the screw rod, the nut 15 is moved toward the proximal end, and the expanded portion 13 protruding toward the back side of the member is bent at the middle portion and bulges outward to form a petal-like shape. It cooperates with the expansion head 12 to pinch and tighten the member, and its usage and function are the same as conventional products.

(Effects of the Invention) According to the present invention, the cylindrical body forming the petal-like expanded portion and the small-diameter tip forming the nut are made from a flat plate by deep drawing, and the grooves are provided by cutting. This has the advantage that there is no waste of material except for the bottom that is removed. In addition, the processing of the cylindrical body and the small diameter tip, the removal of the bottom, the formation of the female thread, and the shaping of the head if necessary are all performed by plastic processing means, making the process simple and easy to process. Suitable for mass production at low cost6

[Brief explanation of drawings]

1 to 7 are explanatory diagrams showing an example of the molding process of the expansion sleeve of the present invention, FIG. 8 is a partially cutaway front view of the product, and FIG. 9 is a bottom view of FIG. 8. 10 to 15 are partial sectional views of an apparatus corresponding to the molding steps shown in FIGS. 2 to 7, and FIG. 16 is a longitudinal sectional view of a conventional expansion sleeve. 1...Flat plate, 2...Groove, 3.4.6.8.10.
...Cylinder, 9.11...Tip, 12...Head, 1
3... Expansion part.

Claims (1)

[Claims] Firstly, a plurality of grooves are provided radially on a flat plate of material by cutting, and secondly, the flat plate is processed into a cylinder with a bottom by deep drawing, leaving the outer periphery, and the tip is made into a small diameter by re-drawing. and thirdly, removing the bottom of the tip by punching and forming a female thread on the inner surface of the small diameter tip by threading.