JPH10113727A - Method for drilling or cutting tubing having elasticity - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make the finish of a cut surface better by fixing a tubing so that its cross section becomes elliptic using dies for strongly sticking a pipe by pressure from the side face of a pipe and thrusting an edge tool from the direction of the major axis of the ellipse. SOLUTION: The pipe 1 is deformed into the elliptic shape, stuck by pressure and fixed with the dies 13, 13' having elliptic faces on their insides and the edge tool 3 is inserted from the direction of the major axis. The part where the pipe 1 is first brought into contact with the edge becomes a state where tensile force is temporarily extremely raised as a result of contraction of the radius of curvature by compression and pressurization in the direction of camber. Consequently, even when cutting is executed separating in two times, the damage of the edge is reduced and the finish of the cut surface is good. After completion of cutting, when the pipe 1 is released from the dies 13, 13', the cross section is restored to the round shape. This method has the advantage because this method is applicable by only the improvement of the die and improvement that the pipe is pressed under pressurization from the side with the existing device and equipment.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for punching or cutting a pipe (pipe) such as metal or plastic by pressing.

[0002]

2. Description of the Related Art A conventional method of punching or cutting a pipe having a circular cross section, such as metal or plastic, by pressing a pipe to be machined is equalized by two dies having an inner diameter slightly larger than its outer diameter. , And the knife has been pushed in while minimizing deformation of the pipe cross section at the start of pressing. After cutting, the cut surface of the pipe is often deformed into a heart shape from the original circular shape due to the pressure of the cutting edge, and it is necessary to finish by secondary processing. Was. Also, in the above-mentioned cutting method, especially in the case of a large-diameter pipe or the like, chips on the pipe wall may be applied to the uncut wall surface, and the cut surface at the festival is rough and the cutting edge is significantly damaged. In addition, if the cutting was performed twice and also performed in the opposite direction, damage to the cutting edge was avoided, but the cross section of the pipe after cutting was often significantly deformed.

[0003]

When a pipe is pierced or cut by a press, it is difficult to finish the inner diameter of a mold for pressing the pipe material very slightly larger than the outer diameter of the pipe. This makes it difficult to press the pipe strongly from the side, and the cut surface of the pipe often deforms into a heart shape, which requires labor and time, such as secondary processing of the cut surface and repeated polishing of the blade. Cost, material loss, etc., and there was a serious problem with the mass production system. Therefore, the pipe is pressurized from the side to increase the tensile strength, and then pierced and cut to obtain a precise finished surface and to solve the above-mentioned drawbacks.

[0004]

According to the present invention, the elasticity of a pipe such as metal or plastic is utilized, and the side surfaces of the pipe are compressed within the elastic limit by means of left and right elliptical concave molds so that the pipe cross section becomes elliptical. The pipe is pierced and cut by pressing and inserting a blade from the major axis direction of the ellipse. Then, when the pipe is released from the mold, the cut surface is restored to the original circular shape by elasticity. If necessary, the blade is pushed in from a different longitudinal direction from the beginning. In the case of the present invention, the work is performed after increasing the tensile strength of the portion where the material first comes into contact with the cutting edge by compression, and the above-mentioned problem is solved.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The apparatus, equipment and operation for carrying out the present invention are basically the same as those of a conventional general-purpose press. Explaining each part of the attached drawings, 1 is a pipe material to be cut, 2 and 2 'are dies for fixing the pipe, which are attached to the press table 9, and 3 is a knife (upper blade) for drilling and cutting. The thickness is 1 to 3 mm, and the lower and upper molds (2, 2 ', 4, 4', 8, 8) for tightening the mold are 4, 4 '.
5, 5 'are upper type (3, 5, 5', 6, 7) cams which are fixed to the upper type set plate 6 and move up and down by a press 7, 8 are slide grooves, and 9 is a press table. , 10
Is a lower mold set plate, 11 is a drilling / cutting knife (lower blade) provided as needed, 12 is a pressing spring prepared in the dies 4, 4 ', and 13 is an elliptical concave crimping die. It is. In FIG. 1, the upper cams 5 and 5 'are turned into the lower cams 4 and 4' immediately before the blade 3 (upper blade) reaches the cutting position in FIG.
, The molds 2, 2 'are tightened via the lower cams 4, 4' to fix the pipe 1, and thereafter the lower cam surfaces 4, 4 'are slid and fixed. The blade 3 cuts while piercing and opening the pipe wall. After the cutting is completed, the cam of the upper blade is separated from the lower die, and the lower die is pulled left and right along the slide groove 8 by the pressing spring 12 charged in the dies 2 and 2 ', and is opened until it hits the stopper. After that, the pipe is opened and removed, and the next pipe material is sent. When cutting is performed twice, the lower blade 11 is also provided in the opposite direction. FIG. 2 is a front view of the pipe cutting portion. In the state immediately before cutting, the upper blade 3a and the upper cams 5a and 5a 'indicated by dotted lines are at the end of cutting, and the upper cam is the lower die. The molds 2 and 2 'are tightened from the left and right by sandwiching the cam. FIG. 3 is a front view of the dies 13a and 13a 'and the lower cams 4 and 4' in the opened state.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The concrete progress of drilling and cutting of a pipe by a press is shown in FIG. 4 in a state where the pipe 1 is crimped to the molds 2 and 2 'with a circular cross section in the conventional working method. Then, pressure is applied from above by the blade 3 to start drilling on the upper surface of the pipe, and chips are projected into the pipe. In FIG. 5, when the blade 3 is pushed down, the pipe side wall is rounded inward so as to be peeled off according to the blade thickness. In FIG. 6, the blade 3 is further pushed down and starts to break through the lower surface of the pipe from the inside,
Chips are pushed out of the pipe. If chips are caught between the lower surface and the blade immediately before this, the load on the blade is extremely increased, and wear and damage often occur. FIG. 7 shows a state immediately before the end of the cutting, but when the lower surface is pierced, the chips are sequentially pushed out of the pipe, and the cutting easily proceeds. FIG. 8 shows a cut surface of the pipe after the completion of the work. Most of the cut surface is deformed into a heart shape that is spread laterally, and secondary processing by a lathe or the like is required. In particular, when cutting is performed twice, deformation of the cut surface becomes more remarkable. In the present invention, the pipe is deformed into an elliptical shape by dies 13, 13 'having an elliptical surface on the inside as shown in FIG. 9, and the pipe is crimped and fixed, and a blade is inserted from the long axis direction. The progress on the way is the same as in the conventional case, but when the pipe is released from the mold, the cut surface is restored to a circular shape by elasticity. In addition, if necessary, as shown in FIG.
There is almost no problem even if two operations of pushing in from the opposite direction are performed.

[0007]

According to the present invention, the molds 2 and 2 'for strongly pressing the pipe 1 from the side are fixed so that the side of the pipe can be compressed from the left and right within the elastic limit and the cross section of the pipe can be made elliptical and fixed. The inner surface of the mold is processed into a short-axis elliptical surface having a radius of curvature larger than the outer diameter of the pipe. Compared with the conventional method of fixing the pipe in a circular shape, the portion where the material of the present invention first comes into contact with the cutting edge has a temporarily increased tensile strength as a result of the reduction of the radius of curvature due to compression and the pressing in the warp direction. It will be in the state that was done. Therefore, even when cutting is performed twice, damage to the cutting edge is small, and the finish of the cut surface is good. As described above, the improvement of the mold and the improvement of the basic element of pressing under pressure from the side, while utilizing the same equipment, facilities and operations as those of the conventional one, provide a much better By obtaining finished products, labor, time, and material losses such as secondary processing have been eliminated, making it possible to shift to a mass production system.

[Brief description of the drawings]

FIG. 1 is a schematic view of a conventional press cutter general-purpose machine.

FIG. 2 is a front view of a cutting section of a general-purpose pipe cutter using a conventional press.

FIG. 3 is a front view of a conventional pipe cutter general-purpose machine using a press when a die at a cutting portion is in an open state.

FIG. 4 is a cross-sectional view of a pipe at the start of drilling in which a cutting edge breaks through and opens a pipe wall by a conventional working method.

FIG. 5 is a cross-sectional view of a pipe when a cutting edge breaks through a pipe wall and cuts to a middle part by a conventional working method.

FIG. 6 is a cross-sectional view of a pipe when a cutting edge starts to break through a lower surface of the pipe by a conventional working method.

FIG. 7 is a cut surface of the pipe just before the cutting edge finishes cutting the pipe by a conventional working method.

FIG. 8 is a sectional view of a pipe formed by a conventional working method.

FIG. 9 is a cross-sectional view of the pipe when the cutting edge starts breaking through the pipe wall in the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pipe material to be cut (pipe) 2 Circular concave fixing die 3 Drilling / cutting blade (upper blade) 4 Lower die cam for die tightening 5 Upper die cam 6 Upper die set plate 7 Upper die elevating Press 8 Slide groove 9 Press table 10 Lower mold set plate 11 Drilling / cutting knife (lower blade) 12 Press spring loaded in mold 13 Mold for crimping elliptical concave surface

Claims (2)

[Claims] 1. An elliptical concave mold 13 or 13 '
And the upper cam 5, via the lower cam 4, 4 'from the side.
A method of tightening by 5 ', fixing the tube so that the cross section of the tube becomes elliptical, and piercing or cutting by pushing the cutter 3 from the major axis direction of the ellipse. 2. A method for piercing or cutting a tubular material according to claim 1, wherein the blade is pushed in from a different longitudinal direction from the beginning.