JPH0251693B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for manufacturing a sleeve for a large-diameter reinforcing bar joint.

(Prior Art) In order to increase the friction force to counter the tensile force acting on the large diameter reinforcing bars, sleeves for joints with large diameter reinforcing bars need to have irregularities such as corrugations on the inner circumferential surface.

For this reason, conventional sleeves are either integrally formed by casting as shown in Japanese Utility Model Publication No. 52-30166, or the inner peripheral surface of a normal sleeve is machined to form irregularities.

(Problems to be Solved by the Invention) However, when the sleeve is formed by casting, it becomes large and thick, and when the inside of the sleeve is cut, the process becomes complicated and costs increase.

This invention was devised to solve the above-mentioned problems, and provides a method for manufacturing a sleeve for reinforcing bar joints, which can form a compact sleeve through a simple process, is easy to work with, and can reduce costs. The purpose is to

(Means for Solving the Problem) This invention forms a plurality of concave portions or convex portions on the outer peripheral surface of a cylindrical core, fits into a sleeve, and rotates a plurality of rolls around the outer circumference of the sleeve. After crimping and applying compressive force, the core is removed from the sleeve and unevenness is formed inside the sleeve.

A truncated conical wedge insertion portion that continues in the longitudinal direction is formed in the core of the core.

The structure of the core consists of a plurality of separate parts with a substantially fan-shaped cross section divided in the circumferential direction.A set of cores is inserted into the sleeve, and a wedge of the same shape is driven into the wedge insertion part of the core to remove the core. The core is fixed, and then a plurality of sets of cores are successively fitted and fixed into the sleeve in the same manner. The outer periphery of the sleeve is crimped with a plurality of rotating rollers while compressive force is applied to feed the sleeve in the axial direction to form irregularities inside the sleeve, and then the wedge is removed and the core is removed.

(Example) The present invention will be described below based on an example shown in the drawings.

As shown in Fig. 1, there are a plurality of annular grooves 2 on the outer peripheral surface.
The cylindrical core 1 having a cylindrical shape formed therein is inserted into the sleeve 7.

The structure of the core 1 consists of a separate section 1a which is divided into four parts in the circumferential direction and has a substantially fan-shaped cross section.
After applying a compressive force to the core 1, the core 1 can be easily removed from inside the sleeve 7.

A wedge insertion portion 3 in the shape of a truncated cone is formed in the core portion of the core 1 and continues in the longitudinal direction.

After inserting the core 1 into the sleeve 7, the core 1 is fixed within the sleeve 7 by driving the wedge 4 into the wedge insertion portion 3 to expand the diameter of the core 1. In order to facilitate insertion of the core 1, the outer diameter of the core 1 and the inner diameter of the sleeve 7 are fitted with a slight clearance. Further, the core 1 is inserted into the sleeve 7 from the smaller diameter side of the wedge insertion portion 3.

In this way, first, one set of cores 1 is inserted into the sleeve 7, and then, in the same manner, multiple sets of cores 1 are inserted into the sleeve 7 so that the outer circumferences of the cores 1 are continuous as shown in FIG. 7 and drive a wedge into each core 1 to secure it. As shown in the figure, the ends of adjacent wedges 4, 4 are brought into contact with each other, and when the lower end of the lowest wedge 4 is struck, the upper wedge 4 is successively pulled out of the core 1. Therefore, a certain clearance is provided between the upper end of the wedge 4 and the lower end of the core 1 directly above the wedge 4.

In addition to the annular groove described above, various recesses 6 and protrusions 5 may be formed on the outer periphery of the core 1 (component 1a). 3 to 5 show examples of the concave portion 6 and the convex portion 5. FIG.

A plurality of rolls 8 are rotated and pressed onto the outer periphery of the sleeve 7 to apply compressive force, thereby forming an uneven portion on the inner surface of the sleeve 7.

Before the compression process, compression force is applied to the upper end of the sleeve 7 using a die 9. (See Figure 1).

In the compression process, as shown in FIGS. 6 and 7, three rolls 8 are compressed around the sleeve 7 while the sleeve 7 is pulled upward in the axial direction. In FIG. 7, the axis of the roll 8 is arranged at an angle of about 45° to 60° with respect to the longitudinal direction of the sleeve 7, but it may be arranged at an angle of 90°.

Finally, the core 1 is removed from the sleeve 7.

In the embodiment shown in FIG. 1, the lower part (the smaller diameter side) of the wedge 4 is struck with a hammer or the like. Then, play is generated between the wedge 4 and the cavity 3 of the core 1, so that the core 1 can be easily removed from the inside of the sleeve 7.

When the core 1 is removed, unevenness is formed inside the sleeve 7 as shown in FIG.

In the embodiments shown in FIGS. 1 to 7, the unevenness inside the sleeve 7 is formed from a large number of equally spaced annular shapes, but in FIGS. An example of forming a is shown below.

A plurality of pairs of cores 1 inserted into the sleeve 7 in succession have a continuous spiral uneven surface formed on their surface, and a spiral convex piece 10 formed on the outer periphery. The three rolls 11 are arranged so that the axes of the rolls 11 are parallel to the axial direction of the sleeve 7, and each roll 11 is rotated while being crimped to the outer periphery of the sleeve 7 while applying compressive force, so that the rolls 11 are rotated in the axial direction of the sleeve 7. This is a method of forming a spiral groove on the outer periphery of the feed.

Example of Using Sleeve An example of using the sleeve 7 manufactured by the above procedure will be described.

As shown in FIG. 11, the upper end of the lower column reinforcing bar 12 and the lower end of the upper column reinforcing bar 13 are inserted into the sleeve 7, and the filler 14 is injected between the reinforcing bars 12, 13 and the sleeve 7 and left for a certain period of time. do.

(Effect of the invention) A core with a plurality of irregularities formed on the outer periphery is inserted into the sleeve, and the sleeve is compressed by crimping the sleeve while rotating a plurality of rolls on the outer periphery of the sleeve, and then the core is removed. Since unevenness is formed on the inner surface, the cost is lower than that in which the sleeve is formed using a plumb structure or the inner surface is machined, and the sleeve can be formed more compactly. It is also easier to work with than those that require cutting.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing an embodiment of the present invention;
The figure is an enlarged cross-sectional view taken along the - line in Figure 1, and Figures 3 to 5.
The figure is a side view of the core components showing an example of unevenness formed on the outer periphery of the core, FIG. 6 is a plan view showing an example of the compression process, FIG. 7 is a side view of FIG. 6, and FIG. 9 is a side view of FIG. 8, FIG. 10 is a sectional view showing an example of the sleeve manufactured according to the present invention, and FIG. 11 is a plan view showing another embodiment of the compression process. FIG. 3 is a sectional view showing an example of the use of the sleeve. 1... Core, 1a... Component, 2... Annular groove, 3... Wedge insertion part, 4... Wedge, 5...
Convex part, 6... Concave part, 7... Sleeve, 8... Roll, 9... Dice, 10... Convex piece, 11... Roll, 12... Lower column reinforcing bar, 13... Upper column reinforcing bar,
14...Filling material.

Claims (1)

[Claims] 1 A set of cores each having a plurality of concave portions or convex portions formed on the outer periphery, a truncated conical wedge insertion portion continuous in the longitudinal direction, and divided into a plurality of pieces in the circumferential direction. Insert the core into the sleeve one by one, drive the wedge into the wedge insertion part of the core, and fix the core in the sleeve so that the outer circumference of the core is continuous.
A sleeve for a reinforcing bar joint, characterized in that a plurality of rolls are rotated and crimped around the outer periphery of the sleeve, applying compressive force to feed the sleeve in the axial direction to form irregularities in the sleeve, and then removing the wedge and core. manufacturing method.