JPH0714713B2 - Manufacturing method of handle ring core metal - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method of manufacturing a ring core metal for a handle.

(Prior Art) A conventional method for manufacturing a ring metal core for a handle is as follows. Approximately 4 times when the metal straight pipe core metal material, which is usually supplied with a length of 5.5 m, is applied to the roll bender.
Wind it in a ring coil shape with a circumference of about 40 cm. Next, the surplus end portions of the ring coil-shaped core metal material are cut into exactly four rounds, and this is cut every one round to form four ring-shaped pipe core metal blanks. . Next, this is set one by one in a butt welding machine and terminal welding is performed. However, in this conventional method, since the length of the straight pipe core metal material is 5.5 m, it takes a lot of man-hours to handle it, and it has a problem that a large space and a large processing facility are required.

Therefore, in order to overcome this problem, a method of welding a straight pipe core metal material to a ring shape by cutting it along with the development of the ring core metal for a handle and cutting it into a ring shape has been attempted, but in this method, It is difficult to form a perfect circle when processing into a ring shape.Therefore, when terminal welding is performed immediately after processing into a ring shape, the end surface of the ring-shaped core metal material is improperly aligned, and the welding strength also decreases. Have a problem to do.

Further, for example, a method for producing a ring-shaped body described in JP-B-53-19473 is known. In this manufacturing method, when a rod having a circular cross section is formed into a ring shape, the curvature in the vicinity of the end faces abutting each other is changed, and the distance between these end faces is formed so as to widen on the center side of the ring. . Next, this rod is pressed from the direction along the central axis of the ring to form a ring whose both side surfaces are flat, and both end surfaces which are butted against each other are made parallel to each other. Then, from these states, both ends are butted against each other and resistance-welded to obtain an annular body.

However, in the method described in this publication, when both end faces are butted and resistance welded, the both end faces are in a state of being parallel to each other, so it is difficult to produce a perfect circle when pressing into a ring shape, Further, since the contact area becomes large, it is difficult to improve the welding strength.

(Problems to be Solved by the Invention) As described above, in the conventional method for manufacturing the ring mandrel for a handle, a long straight pipe mandrel material is processed into a ring coil shape and then cut every one turn. However, there is a problem that it requires a large number of man-hours, a large space, and a large processing facility, and it is difficult to form a perfect circle by the method of cutting the linear pipe core metal material according to the developed length of the ring core metal. However, there is a problem that the welding strength decreases. Further, in the manufacturing method described in Japanese Patent Publication No. 53-19473, when both end faces are butt-welded and resistance-welded, since both end faces are in a state of being parallel to each other, a perfect circle is formed when processing into a ring shape. It is difficult to start the welding, and since the contact area is large, it is difficult to improve the welding strength.

The present invention is intended to solve the above-mentioned problems, and in manufacturing a handle ring core metal, a manufacturing process,
The purpose of the present invention is to reduce the space, reduce the size of the processing apparatus, and reduce the cost, and also to ensure that the ring core metal is a perfect circle and to increase the welding strength.

(Means for Solving Problems) In the method for manufacturing a handle ring cored bar of the present invention, a linear cored bar material is cut in accordance with the developed length of the handle ring cored bar, and cut into this expanded length. The core metal material is processed into a ring shape, and the end portions of the core metal material processed into the ring shape that are abutted against each other are pressed toward the center of the ring formed by the core metal material, and elastically deformed toward this center direction. The welding is carried out in the state of being kept, and after this welding, the pressure is released to spring back the terminal portion.

(Operation) In the method for manufacturing a handle ring core metal of the present invention, the abutted end portions of the core metal material processed into a ring shape are pressed toward the center of the ring formed by the core metal material, By elastically deforming toward the end, the abutting of the end portions is ensured, and the welding strength of the end portions in this state is increased. When the pressure is released and the end portion is springed back after the welding, a ring cored bar having a shape close to a perfect circle including the end portion that is hard to form a perfect circle is obtained.

(Example) Hereinafter, one example of a method for manufacturing a ring core metal for a handle according to the present invention will be described with reference to the drawings.

First, a standard length (5.5 m) metal straight pipe core metal material 1A
As shown in FIG. 1, the ring cutter is set on the pipe holder 3 of the pipe cutter 2 and fixed by the ring clamp 4, and the rotary blade 6 of the vertically movable metal saw 5 extends the developed length of the ring core bar, for example, 110 to Cut to 120 cm. FIG. 2 shows the pipe core metal material 1B cut into the developed length.

Next, as shown in FIG. 3, the core metal material 1B is set on the pipe holder 12 of the chamfering machine 11 and fixed by the ring clamp 13, and the chamfering blade 15 is rotated by the drive of the motor 14 to be advanced. As a result, both end faces of the core metal material 1B are chamfered. FIG. 4 shows a sectional shape of the chamfered portion 16.

Next, as shown in FIG. 5, the chamfered core metal material 1B is supplied to the roll bender 21 by using the feed roll 22. In the roll bender 21, the intervals between the vertically movable rolls 23a, 23b and 23c of the non-driving bending roll group 23 and the main roll 24 which is a driving roll are adjusted in advance so that a predetermined R shape is obtained. The core material
After 1B goes around the outer circumference of the main roll 24, the ring-shaped core metal material 1C shown in FIG. 7 is formed.

At that time, as shown in FIG. 6, when the core metal material 1B is introduced into the roll bender 21, the tip end 25 of the core metal material 1B entered from the first roll 23a of the bending roll group 23 is changed to the second end. Roll 2
The core metal material 1B does not receive bending stress until it reaches 3b, and a portion of length l ₁ corresponding to the distance between the both ends 23a and 23b from the tip end 25 of the core metal material 1C processed into a ring shape. Remains linear as shown in FIG. Further, as shown in FIG. 7, the portion of the core metal material 1C having a length l ₂ from the terminal end 26 is also deviated from the perfect circle due to the spring back.
Then, due to the deviation of the both end portions 27, 28 of the core metal material 1C from the perfect circle, the ends 25, 2 of the ring-shaped core metal material 1C are
As shown in FIG. 7, the butt surface of 6 opens in a V shape toward the outer peripheral side. In the past, this was the cause of lowering the welding strength.

Next, in the welding process, as shown in FIG. 8, the butt welding machine 31 used there also serves as a lower electrode for receiving both end portions 27, 28 of the core metal material 1C processed into the ring shape. It also has a pair of receiving jigs 32, 33. As shown in FIG. 9, which is a side view, these receiving jigs 32, 33 have receiving grooves 34, 35 into which the end portions 27, 28 of the core metal material 1C are fitted. Further, as shown in FIG. 10 which is a sectional view taken along line XX of FIG. 9, bottom portions 34 of these receiving grooves 34, 35 are provided.
a, 34b, 34c, 35a, 35b, 35c, with the central portion 24b, 35b as a boundary, the adjacent portions 24a, 35a have a downward slope toward the outer end, and the central portion 34b, 35b The parts 34c, 35c separated from each other as a boundary have the same shape as the inner circumferential arc C of the ring formed on the core metal material 1C.

Then, as shown in FIG. 8, both end portions 27, 28 of the core metal material 1C are set in the both receiving grooves 34, 35, respectively, and both end portions 27, 28 are shown in FIG. As described above, the pair of vertically movable upper electrodes 36 and 37 is tightened from above to elastically pressurize and deform in the direction of the center O of the arc C formed by the core metal material 1C, that is, toward the inner peripheral side. At this time, the terminal of core metal material 1C
As shown in FIG. 12, the abutting surfaces of 25 and 26 open in a cross shape in the direction of the center O.

Next, in this state, one receiving jig, that is, the lower electrode 32, which is movable in the lateral direction, is fixed to the other receiving jig, that is, the lower electrode, which is fixed by the swingable side pressurizer 38 shown in FIG. The core metal material 1C is moved toward 33 to press the abutting surface of the core metal material 1C in the circumferential direction, and then energized for about 0.3 seconds to resistance-weld both ends 25 and 26 of the core metal material 1C. Incidentally, one upper electrode 36 corresponding to the one movable lower electrode 32.
Is also movable in the horizontal direction, and the other upper electrode 37 corresponding to the other fixed lower electrode 33 does not move in the horizontal direction.

In the above welding, as shown in FIG. 12, the abutting surfaces of the ends 25 and 26 of the core metal material 1C are V-shaped and open toward the center O of the arc C formed by the core metal material 1C. Therefore, in the past, the welding strength tended to decrease.
Sufficient welding strength can be obtained also on the outer peripheral sides 41, 42 of the 5, 26. Further, since the terminals 25 and 26 are chamfered, the contact area is small, and therefore the welded portion 43 is melted at a higher temperature, and the melted portion is formed by the chamfered portion 44.
By filling the gap, the welding strength is further improved and burrs are reduced.

After welding, the clamps 45 and 46 shown in FIG. 8 are released, the upper electrodes 36 and 37 are raised, and the welded ends 27 and 28 of the core metal material 1C are springbacked. At this point, since the terminal portions 27, 28 were pressed toward the inner peripheral side, the deviation from the perfect circle of these terminal portions 27, 28 was corrected, and for the substantially circular handle. A pipe core metal is obtained.

(Effect of the invention) According to the present invention, since the core metal material cut in advance according to the developed length of the handle ring core metal is pressed into a ring shape, handling of the core metal material becomes very easy, and the manufacturing process,
It is possible to significantly reduce the space, reduce the size of the processing equipment, and greatly reduce the cost. Also, press the end of the ring-shaped cored bar material abutted against each other toward the inner peripheral side of the ring. After welding while elastically deforming toward the center, the pressure is released and the end portion is spring-backed, so as described above, cut the core metal material into a ring shape according to the expanded length. Despite pressurization, the ring core metal can be surely made into a perfect circle, and the welding strength is also improved. .

[Brief description of drawings]

FIG. 1 is a front view of a pipe cutter used in an embodiment of a method for manufacturing a ring core metal for a handle of the present invention, FIG. 2 is a perspective view of a core metal material cut by this pipe cutter, and FIG. A front view of a chamfering machine for chamfering a core metal material, Fig. 4 is a sectional view of the chamfered core metal material, Fig. 5 is a front view of a roll bender for processing the core metal material into a ring shape, and Fig. 6 is A front view of the operation explanation, FIG. 7 is a front view of a core metal material processed into a ring shape, FIG. 8 is a front view of a butt welding machine for welding the core metal material, and FIG. 9 is a receiving jig thereof. A side view, FIG. 10 is a sectional view taken along line XX of FIG. 9, FIG. 11 is a sectional view of the same position as FIG. 10 during welding, and FIG. 12 is an enlarged view of the vicinity of the end of the core metal material of FIG. It is a figure. A: Straight core material, 1B: Cut core material, 1C
…… Core metal processed into a ring shape, 27, 28 …… End part, C …… Arc of the ring formed by the core metal, O …… The center.

Claims (1)

[Claims] 1. A step of cutting a linear core metal material in accordance with a development length of a handle ring metal core, a step of processing the core metal material cut to the development length into a ring shape, and a step of forming the ring shape. A step of pressing the abutted end portions of the processed core metal material toward the center of the ring formed by the core metal material, and welding while elastically deforming toward the center direction; And a step of springing back the terminal portion to release the pressure.