JPH03104992A - Twisting processing of twisted wire end of pc steel - Google Patents

Abstract

PURPOSE:To form accurate screws without causing deviation of twisting and damaging roundness by forming a small diameter part at the edge part of twisted wire of PC steel and subjecting the small diameter part including the outer periphery part thereof to roll screw processing in a stuck state of the small part to a metal ring. CONSTITUTION:The outer periphery of end edge part of twisted wires 1 and 1A of PC steel of twisted plural elements wires 2 and 2A is shaved off in stages to form small diameter parts 7 and 7A, which are inserted into a metal ring 10 having smaller outer diameter than the outermost diameter of the twisted wires of the PC steel and the rings are stuck to the small diameter parts under pressure. Then, the outer periphery at the edge part of the twisted wires of PC steel is subjected to rolling screw process to carry out screw processing of edge part of twisted wires of PC steel.

Description

[Detailed Description of the Invention] (Industrial Application) The present invention fixes the tension force after stress introduction to the outer periphery of the end of the PC steel stranded wire used for stress introduction into prestressed concrete using a nut. This article relates to a method for machining end threads of PC steel stranded wire to form threads for use in the manufacturing process. (Conventional technology and its problems) PC used for introducing stress into grestress concrete
For the M material, a PC steel rod made of a single wire and a PC steel stranded wire made of multiple single wires twisted together are used. The PCw4 rod, which is made of solid wire, has a male thread carved mainly on the outer periphery of the end, and after stress is introduced, the end is fixed using a nut screwed onto the outer periphery of the male thread. On the other hand, the PC steel stranded wire mainly uses a wedge made by dividing a Taber cylinder into multiple parts and a cone with a taper six opening through the outer periphery of the end. Generally, the ends are fixed by crimping. Fixing with a nut is IA'zH compared to fixing with a wedge.
There is no need to consider later return, and the wedge and P
(Jl4 material has high reliability because no slipping occurs between the surfaces, and it is economical because it does not require complicated devices such as cones with tapered holes, wedges, and wedge prevention devices. On the other hand, PC steel stranded wires are more flexible than PC steel rods and are convenient for curved installation, and they can also be attached to concrete to introduce prestress. When used in a so-called bond type prestressed concrete structure, the surface has a spiral pattern, so it is suitable for adhesion when embedded in concrete.However, conventionally, thread processing for PC steel strands is considered impossible, and
・It has been said that there is no choice but to rely on wedge fixation instead of fixation. When threading prestressing steel, it is necessary to process the threads without cutting the longitudinal metal weave in order to avoid reducing the tensile strength. When processing thread rolling, the pressure from the outer periphery makes it easy to twist or untwist, especially in the fukube part, causing misalignment between single strands, and the roundness at the outermost diameter of the entire stranded wire during processing. The problem was that the threads were not properly formed, and even after the thread was machined, the threads came loose, making it difficult for the nut to screw in and out smoothly. (Problems to be Solved by the Invention) In view of the above-mentioned conventional problems, the present invention provides an accurate rolling thread formed at the end of a PC stranded steel wire having a spiral thread on the outer periphery. The purpose of this invention is to provide a method for machining end threads of PC steel strands, which does not impair the smooth threading of the nut after machining. (Means for Achieving the Object) The feature of the method for threading the end of PC@1 stranded wire of the present invention in order to solve the above-mentioned conventional problems and achieve the intended purpose is that it has a plurality of elements. The outer periphery of the end of the PC steel stranded wire, which is made by twisting the wires, is scraped in steps to form a small diameter part, and a metal ring having an outer diameter smaller than the outermost diameter of the PC steel stranded wire is fitted into the small diameter part and crimped. After that, the outer periphery of the end of the PC stranded wire is thread-rolled. The metal ring should have approximately the same outer diameter as the PC steel stranded wire, and the outer periphery of the metal ring may be continuous with the outer periphery of the PC steel stranded wire. It is also possible to use a wire with an outer diameter smaller than the diameter of the trough of the thread formed on the stranded wire, and to perform thread rolling only on the outer periphery of the PCM stranded wire. Furthermore, the PC steel stranded wire may be made by twisting a plurality of wires together and then reducing the diameter by cold drawing using a circular die. (In this method, the small diameter part is shaped by cutting the edge of the P C j!4 stranded wire into a step shape, and by crimping a metal ring to this, the separation of the strands at the end is prevented. At the same time, the pressure from the outer periphery during rolling thread processing also corrects the misalignment between the strands, prevents deformation of the outer diameter, and creates highly accurate threads. The nut can be fitted and screwed forward and backward while the metal link S is crimped, and unraveling over time is completely prevented, and smooth screwing forward and backward movement of the nut is maintained. (Example) Next Embodiments of the present invention will be explained with reference to the drawings.
FIG. 2 shows different examples of stranded PC steel wires to be threaded in the present invention. The PC steel strand 1 shown in FIG.
It shows multiple twisted cables with a circular cross section.
Seven side wires around one wooden core element VA2 3.3...
... are twisted together in a spiral shape, and the cable wires 23 made of prestressed steel wires are twisted together and then treated with blue ink to remove the residual stress caused by the processing. Second
The PC steel stranded wire IA shown in the figure is produced by cold drawing the PC steel stranded wire 1 shown in FIG. 1 through a die 4 having a circular cross section as shown in FIG. ．． While crushing the spiral gap 5 between 3A, the outer periphery 1{! I element full3
The spiral 6 between A and 3A is also crushed to make the whole cross-section close to a solid circular cross section. This PC steel stranded wire 1 or I
A is cut to a predetermined length, and the outer periphery of the end is shown in Figure 4 (a) and (b) for PC* stranded wire 1, and as shown in Figure 5 for PC stranded wire IA.
As shown in Figure (a) (opening), cut into steps to form a small diameter portion 7 or 7A with a circular cross section. This small diameter portion 7 or 7A is formed by fixing the PC steel strands 1 or IA with a chuck 8 as shown in FIG. Cut it out. Alternatively, a lathe may be used. Next, the steel ring 10 is fitted onto the outer periphery of the small diameter portion 7 or 7A and crimped by crimping from the outer periphery. The steel ring 10 crimped in this way is then crimped with a PC as shown in FIG.
The diameter may be approximately the same as the maximum outer diameter of the stranded steel wire 1 or IA, or it may be smaller than the minimum diameter of the threaded swamp portion described later, as shown in FIG. After crimping the steel ring 10 in this way, the @
PC including the outer circumference of 10 parts of the manufactured ring! 4 strands 1 or 1
The end of A is thread-rolled using a rolling roll l1 as shown in Fig. 9. As a result, as shown in Fig. 7, the outer diameter of the steel ring IO is PCI! 4 twist fit or IA
A steel ring 10 with a diameter close to that of the steel ring 10 has a continuous rolled thread 12 formed on the outer surface of both rings as shown in FIG. As shown in Figure 11}) C A thread l2 is formed only on the outer periphery of the steel strand l or 1A. (Effects of the Invention) As described above, the method for processing the ends of stranded PC steel wires according to the present invention involves forming a small diameter portion at the end of a stranded PC steel wire, and crimping a metal ring on the small diameter portion. By applying the thread rolling process to the outer periphery of the wire, there is no possibility that the twisting between the strands will shift or the roundness of the entire wire will be lost due to the pressure applied during rolling. An accurate thread is formed without any problems, and the crimped ring can be fitted with a nut while maintaining the crimped state even after the thread is rolled, so there is no possibility that the twist will unravel over time and the thread will become deformed. This eliminates this problem, and maintains the nut's smooth threading forward and backward movement.This makes it possible to fix the PC steel strands in one nut, and provides highly reliable fixation with a simple device similar to the PC steel rod. This is what happened here.

[Brief explanation of drawings]

The drawings show embodiments of the invention. Figure l, 2nd
The figure is a cross-sectional view of each separate PC steel stranded wire to be threaded according to the present invention, Figure 3 is a cross-sectional view showing the state of cold drawing, Figure 4 (A) (opening) is the same as Figure 5. Figure (a) (b)
Figure 2 shows a side view and a front view of the PC steel stranded wire having a small diameter part formed therein, and Figure 6 shows the process of forming the small diameter part.
Figures 7 and 8 are sectional views showing different examples of crimped steel rings, Figure 9 is a front view of the rolling process, and Figure 10 is a front view of the rolling process.
Figure 11 is an illustration of the PC steel strands after forming separate screws.

Claims (4)

[Claims] (1) The outer periphery of the end of a PC steel stranded wire made by twisting a plurality of wires is shaved off in steps to form a small diameter part, and the small diameter part is filled with metal having an outer diameter smaller than the outermost diameter of the PC steel stranded wire. A method for threading an end of a stranded PC steel wire, the method comprising fitting and crimping a ring, and then applying a thread rolling process to the outer periphery of the end of the stranded PC steel wire. (2) The PC steel according to claim (1), wherein the metal ring has approximately the same outer diameter as the PC steel stranded wire, and a thread rolling process is applied continuously to the outer periphery of the metal ring and the outer periphery of the PC steel stranded wire. How to thread the ends of stranded wire. (3) Use a metal ring with an outer diameter smaller than the diameter of the trough of the thread formed on the PC stranded wire, and apply rolling thread processing only to the outer periphery of the PC steel stranded wire. How to thread the part. (4) According to claim (1), (2) or (3), the PC steel stranded wire is obtained by twisting a plurality of wires together and then reducing the diameter by cold drawing using a circular die. How to thread the ends of stranded PC steel wire.