JPH05305383A - Sleeve with split groove and manufacture thereof - Google Patents

Abstract

PURPOSE:To provide a sleeve having split grooves manufactured by a cold forging only without using cutting work and a manufacturing method by which the sleeves are mass-produced at a low cost. CONSTITUTION:In a deep hole forming process, a flange-shaped head 3 is preliminarily formed at one end of a short columnar material 1 obtained by cutting a metallic wire material in a specific length and a deep hole 4 extending from the other end up to the vicinity of the flange-shaped head 3 is extruded to form a sleeve main body 5. In a second process, a groove forming center pin provided with plural protruded line blades on its outside circumference in the axial direction is inserted into the deep hole 4 by pressure to form plural split grooves 7 having remaining thin part 8 on their outside faces and extending in the axial direction on the inside face of the deep hole 4. In a groove forming process, a flanged part 6 is formed by pressurizing the flange-shaped head 3. In a trimming process, the cylindrical sleeve is formed by blanking burrs 10 generated when the grooves 7 are formed and a bottom part 9 remaining at the flanged part 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a grooved sleeve suitable as a grooved sleeve for an expansion anchor fixed to a concrete skeleton and a method for producing the same.

[0002]

BACKGROUND OF THE INVENTION An expansion anchor usually comprises a sleeve with a split groove having a plurality of split grooves extending in the axial direction at the end of a cylindrical sleeve, and a truncated cone wedge body. The wedge body is press-fitted in to expand the expansion portion provided with the split groove, and is fixed to the side wall surface of the prepared hole of the concrete skeleton body.

Conventionally, such a grooved sleeve of an expansion anchor has a sleeve body obtained by cutting a metal pipe material to a predetermined size by cutting, and a plurality of grooved grooves extending axially from its open end. It was manufactured by cutting with a milling cutter.

[0004]

However, the above-mentioned conventional method by cutting has a problem that the working efficiency is low, the machining cost of the split groove is particularly high, and the manufacturing cost is high.

The present invention has been made in view of the above circumstances, and provides a sleeve with a split groove manufactured by only cold forging without using a cutting process, and a manufacturing method capable of mass-producing the sleeve with the split groove at low cost. The purpose is to

[0006]

To achieve the above object, a sleeve with a split groove of the present invention is manufactured by cold forging from a cylindrical metal material, and has a flange portion at one end of a cylindrical sleeve, Extends in the axial direction from the other end opening to the inner wall surface,
Further, it is characterized in that it has a plurality of grooves in which the thin portion remains on the outer side surface. When it is used as an expansion anchor, it is desirable that the thin portion be broken by a certain length from the open end of the sleeve.

Further, in the method of the present invention for producing the sleeve with the split groove, a flange-shaped head is preformed on one end of a short columnar material obtained by cutting a metal wire rod into a predetermined size, and the other end is subjected to the above-mentioned process. A deep hole forming step of extruding a deep hole extending to the vicinity of the flange-shaped head to form a bottomed cylindrical sleeve body, and a plurality of projections extending axially on the outer peripheral surface of the deep hole of the sleeve body. A center pin provided with a line blade is press-fitted to form a plurality of grooves axially extending on the inner wall surface of the deep hole and having a thin portion remaining on the outer surface, while compression molding the flange-shaped head portion. And a groove forming step of forming a flange portion, a flash generated at the time of forming the groove, and a trimming step of punching out a bottom portion of the deep hole remaining in the flange portion to form a cylindrical sleeve. It has a feature.

[0008]

In the method of the present invention, a sleeve with a split groove is manufactured by only cold forging without using any cutting work.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a manufacturing process sequence of a sleeve with a split groove according to the method of the present invention, FIG. 2 is an explanatory view showing a deep hole forming process, FIG. 3 is an explanatory view showing a groove forming process, and FIG. [FIG. 3] is an explanatory diagram of a trimming process.

The raw material 1 is a short columnar body obtained by cutting a mild steel wire rod to a predetermined size. First, both end faces of the raw material 1 are straightened by punches not shown, and core processing for forming the recesses 2 and 2 is performed. (See FIG. 1 (b)).

Next, as shown in FIG. 2, the material 1 is compression-molded by using the die 21 and the punch 22, the flange-shaped head 3 is preformed at one end, and the center pin 23 is press-fitted into the die 21. A deep hole 4 extending from the other end of the material 1 to the vicinity of the flange-shaped head 3 is extruded to form a bottomed tubular sleeve body 5 (see FIG. 1C). Reference numeral 24 is an erection device.

Subsequently, as shown in FIG. 3, the sleeve main body 5 is inserted into and supported by the die 25, and the head 3 is compression-molded by the punch 26 to form the flat circular flange portion 6, while the outer periphery thereof is formed. A groove forming center pin 27 having a plurality of (four in the illustrated example) projecting blades 28 extending in the axial direction with a triangular cross section on the surface is press-fitted into the deep hole 4, and the inside of the deep hole 4 from the opening end 4a. A V-shaped split groove 7 is formed on the wall surface, extending in the axial direction by a predetermined length, and having a thin portion 8 remaining on the outer wall surface. At this time,
The bottom portion 9 of the deep hole 4 is formed thin by recessing the central portion of the flange portion 6. In addition, a flash 10 is generated at the inner end of the split groove 7 during molding (see FIG. 1D).

Next, as shown in FIG. 4, the sleeve body 5
With the die 30 and punch 31 supporting the trimming center pin 32 in the deep hole 4, the flash 10 is removed, the bottom 9 is punched out, and the cylindrical sleeve 11 having the flange 6 at one end is removed. It is formed. At this time, the thin blade portion 8 of each split groove 7 is broken by a predetermined length S from the opening end 4a by the breaking blade 33 protruding from the outer peripheral surface of the center pin 32 to form the breaking portion 12. By providing the breakage portion 12 in this way, when the cylindrical sleeve 11 is used as the sleeve of the expansion anchor as described later, the expansion resistance of the sleeve tip portion can be greatly reduced. Thus, as shown in FIG. 7, the flange portion 6 is attached to one end of the cylindrical sleeve 11.
Has a plurality of split grooves 7 extending in the axial direction from the opening end 4a to the inner wall surface and having the thin portion 8 remaining on the outer surface. Fracture part 12
Thus, the sleeve 13 with the split groove is completed. Furthermore, it is also possible to form an internal thread (not shown) on the inner wall surface of the cylindrical sleeve 11 to form an internal thread sleeve.

Further, in the groove forming step shown in FIGS. 4D and 3, it is possible to form the rotation preventing projection 14 which protrudes in the radial direction below the flange portion 6 as shown in FIG. is there. At the same time, the opening end 4a of the deep hole 4 for forming the split groove 7 is chamfered by the groove forming center pin 27 so that the outer end of the open leg portion 15 formed between the split grooves 7 is expanded outward. It is also possible to form the tapered surface 16. When the tapered surface 16 that expands outward is provided in this manner, the spread of the open leg portion 15 during use is further facilitated, which is effective.

In the deep hole forming step shown in FIGS. 1C and 2, it is possible to change the diameter of the center pin 23.
The wall thickness of the sleeve body 5 can be arbitrarily increased or decreased. This facilitates designing the expanding leg portion 15 to be expanded to a desired strength when the split groove sleeve 13 is used as a expanding anchor.

FIG. 9 shows another manufacturing process sequence according to the method of the present invention. The point that the core 1 is formed by forming the material 1 and the recesses 2 on both end surfaces of the material 1 is shown in FIG. 1 (a).
Since it is the same as the step shown in (b), it is omitted.

FIG. 9C shows a deep hole forming step. In this step, prior to the extrusion of the deep hole 4 and the formation of the bottomed tubular sleeve body 5, the flange-shaped head 3 is preformed at one end of the material 1 and at the same time subjected to the drawing process to form the groove. The sleeve portion 5A to be processed is formed into a stepped shaft by forming it into a smaller diameter than the remaining sleeve body 5. Subsequently, as shown in FIG. 9 (d), a plurality of split grooves 7 extending in the axial direction on the inner wall surface of the deep hole 4 and having the thin portion 8 remaining on the outer surface are formed in the sleeve portion 5A, and at the same time, the head portion is formed. The portion 3 is compression molded to form the flange portion 6. Further, as shown in FIG. 9E, the flash 10 is removed and the bottom portion 9 is punched out to complete the sleeve 17 with the split groove.

Similarly to the sleeve 13 shown in FIG. 8, the sleeve 17 with the split groove manufactured by the above process has the leg opening formed between the rotation preventing projection 14 and each split groove 7 in the groove forming process. It is possible to form the tapered surface 16 inside the tip of the portion 15.

FIG. 10 shows an example in which the sleeve 13 with a split groove manufactured as described above is used as an expansion anchor. The expansion anchor 40 has a taper cone 42 at one end of an anchor bolt 41 inserted into the sleeve 13 with a split groove.
And has a threaded portion 43 at the other end. Then, the taper cone 42 is press-fitted into the cylindrical hole 4 from the opening end 4a by tightening the nut 44 screwed to the threaded portion 43, and the thin portion 8 of the split groove 7 is broken by the wedge action thereof, and each split groove is broken. The open leg portion 15 formed between 7 is expanded and fixed to the side wall surface of the prepared hole of the concrete skeleton.

[0021]

As described above, the sleeve with a groove according to the present invention is manufactured only by cold forging without using any cutting process, so that the manufacturing cost is greatly reduced as compared with the cutting process. Not only can this be done, but the outer shape or wall thickness of the sleeve body can be easily changed, so that it is particularly suitable for the sleeve with the split groove of the expansion anchor.

Further, since the flange portion is integrally formed at one end of the sleeve body, the flange portion also serves as a washer, and in the case where a female screw is formed on the inner wall surface of the sleeve body, By using the flange portion, thread processing can be easily automated.

On the other hand, according to the method of the present invention, the sleeve with the split groove having the above-mentioned structure can be mass-produced at low cost.

[Brief description of drawings]

FIG. 1 is an explanatory view of a manufacturing process of a sleeve with a split groove according to the method of the present invention.

FIG. 2 is a vertical cross-sectional view showing the same deep hole forming step.

FIG. 3 is a vertical sectional view showing the groove forming step.

FIG. 4 is a vertical sectional view showing the trimming step.

FIG. 5 is a perspective view showing a main part of a groove forming center pin.

FIG. 6 is a perspective view showing a main part of a trimming center pin.

FIG. 7 is a perspective view of a sleeve with a split groove according to the present invention.

FIG. 8 is a front view (d) and a side view (b) of the grooved sleeve according to the present invention which has been subjected to additional processing.

FIG. 9 is an explanatory view of another manufacturing process according to the method of the present invention.

FIG. 10 is a vertical sectional front view of a main part of the expansion anchor using the sleeve with the split groove according to the present invention.

[Explanation of symbols]

 1 Material 2 Recess 4 Deep Hole 5 Sleeve Body 6 Flange 7 Split Groove 8 Thin Wall 9 Bottom 10 Burr 11 Cylindrical Sleeve 12 Breaking Section 13, 17 Split Groove Sleeve 27 Groove Forming Center Pin 28 Ridge Blade 32 For Trimming Center pin 33 Fracture blade

Claims (8)

[Claims] 1. A cylindrical metal material manufactured by cold forging, having a flange portion at one end of a cylindrical sleeve, extending axially from the opening at the other end to the inner wall surface, and leaving a thin portion on the outer surface. A sleeve with a split groove, which has a plurality of grooves. 2. The sleeve with a split groove according to claim 1, wherein the thin portion is broken from the opening end of the sleeve by a predetermined length. 3. The sleeve with a split groove according to claim 1, further comprising a rotation preventing protrusion that protrudes in a radial direction on a lower side of the flange portion. 4. The outer diameter of the sleeve portion provided with the groove is
The sleeve with the split groove according to claim 1, wherein the sleeve has a smaller diameter than the remaining sleeve portion. 5. A flange-shaped head is preformed on one end of a short columnar material obtained by cutting a metal wire into a predetermined size, and a deep hole extending from the other end to the vicinity of the flange-shaped head is extruded. Then, a deep hole forming step of forming a bottomed tubular sleeve body, and a center pin provided with a plurality of protruding blades extending in the axial direction on the outer peripheral surface is press-fitted into the deep hole of the sleeve body, A groove forming step of axially extending on the inner wall surface of the deep hole and forming a plurality of grooves in which the thin portion remains on the outer surface, while forming the flange portion by compression forming the flange-shaped head portion, A method for manufacturing a sleeve with a split groove, comprising: a flash produced during molding of the groove and a trimming step of punching out a bottom portion of the deep hole remaining in the flange portion to form a cylindrical sleeve. 6. The method for manufacturing a sleeve with a split groove according to claim 5, wherein in the trimming step, the thin portion is broken from the opening end of the sleeve body by a predetermined length. 7. The method for manufacturing a sleeve with a split groove according to claim 5, wherein, in the groove forming step, a detent protrusion protruding in the radial direction is formed on the lower side of the flange portion. 8. The method according to claim 5, further comprising a step of forming the outer diameter of the sleeve portion to be grooved to be smaller than the remaining sleeve portion, following the deep hole forming step.
Alternatively, the method for manufacturing the sleeve with the split groove according to the item 7.