JP2002028814A - Tube cutter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tube cutter capable of cutting a round tube and a square tube and dispensing with finishing after cutting. SOLUTION: In the round tube cutter, the upper ends of a stationary die 4 and an elevating knock-out member 3 are formed as a semi-cylindrical surface, and the upper end of the die is formed as a shearing blade. In shearing, a slide punch 6 and a stationary fixed punch 7 are disposed as a core metal in a round tube A, the right end edge of the slide punch and the left end edge of the fixed punch are formed as a shearing blade, a punch 8 and a stripper 9 are disposed in positions corresponding to the knock-out member 3 and the die 4 above the round tube, the lower end of the punch is formed as a shearing blade, and the right end edge of the punch and the left end edge of the fixed punch, and the right end edge of the slide punch and the left end edge of the die are respectively disposed with each precise shearing clearance between them.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pipe cutting apparatus, and more particularly to a pipe cutting apparatus which does not require any secondary processing after cutting a pipe.

[0002]

2. Description of the Related Art In conventional pipe cutting, a cut surface is roughened and a cutting burr is generated, so that cutting as a secondary process is required after cutting. Therefore, the pipe shearing step is costly, and the feature of cutting by the upper die for pipe processing has not always been said to be advantageous.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to devise a pipe and tube cutting device which does not require any finishing after cutting.

[0004]

According to the present invention, the set task is solved by the features described in claims 1 to 4.

The tube cutting device according to the present invention minimizes the shear energy by limiting the effective shear stroke to the order of the wall thickness of the tube, thereby being applicable to both thick and thin tubes. Also, by applying precision shearing clearance, so-called "zero cutting", i.e., precision shearing of the tube, can be performed without any finishing of the cut surface after cutting. The pipe cutting device according to the present invention comprises:
The present invention can be suitably applied to the cutting of a thin stainless steel tube.
The pipe cutting apparatus according to the present invention has no burrs due to cutting in one step of the pipe, and has a cutting surface roughness and a cutting accuracy of 0.01 m.
A precision cut of the order of m, without finishing of the cut surface, is achieved, which enables high-precision, high-speed and low-cost ring production.

The present invention will be described in detail with reference to the illustrated embodiment.

[0007]

1 to 4 show a round tube cutting apparatus as a first embodiment of a pipe cutting apparatus according to the present invention.

First, the overall configuration of the round tube cutting device will be described.

The base plate 1 can be fixed on a work table of a press machine (not shown). On the base plate 1, a shearing device for cutting a round tube A as a workpiece into a ring of a predetermined length is arranged. The axial interval of the round tube A is specified between the back stopper 2 fixed on the base plate 1 and the die 4, and the knockout member 3 is provided via two springs 5 arranged at a constant interval. A slide punch 6 and a fixed punch 7 as a metal core are disposed above the knockout member 3 and the die 4 elastically on the base plate 1, and a punch 8 and a stripper 9 are respectively disposed above the slide punch 6 and the stripper 9. Are located. The upper surface of the stripper 9 is formed in a plane, and two springs 10 arranged at regular intervals are arranged on the upper surface of the stripper 9. The spring 10 is a punch plate that supports the punch 8. The upper end of the spring 10 is supported by a base holder 12 fixed to a punch plate 11, and the lower end of the spring 10 presses the stripper 9 downward. The base holder 12 is fixed to a driving ram of a press machine (not shown), and is driven to move up and down by a raising and lowering motion of the driving ram. Round tube A to be cut
2 is loaded into the shearing device from the left side of FIG. 2, the round tube A being on the knockout member 3 and the die 4 via the slide punch 6 and the fixed punch 7 at the bottom and similarly at the slide punch 6 and fixed at the top. It is held by a punch 8 and a stripper 9 via a punch 7. At that time, fixed punch 7
To restrict the position of the round tube A in the axial direction and the round tube A
In order to reject the ring caused by the cutting, a knockout 13 consisting of a flange and a hollow tube is guided so as to be movable in the axial direction of the round tube A along the outer periphery of the fixed punch 7 so as to be slidable in the axial direction. I have.

On the base plate 1, a bracket 14 is provided.
Are fixed, and the bracket 14 fixes the fixing plate 15 immovably in the axial direction of the round tube A. Fixing plate 15
The fixed punch 7 is fixed by a stopper pin 16. In order to prevent rotation of the fixed punch 7, the right end region of the fixed punch 7 has a D-shaped cross section and can be fitted into a correspondingly D-shaped hole of the fixing plate 15. On the other hand, the knockout 13 is connected to two knockout operation rods 17 arranged at a distance from each other, and the knockout operation rod 17 is guided by the bracket 14 so as to be movable in the axial direction of the round tube A. The knockout operation rod 17 is driven by a piston cylinder unit 20 connected via a slide plate 18. The piston cylinder unit 20 is mounted on a cylinder base 19 welded on the base plate 1. Cylinder table 1
Reference numeral 9 denotes a portion fixed to the base plate 1 and a portion fixed to the base plate 1 and extending from the base plate 1 to the right in FIG.

The configuration of the round pipe shearing mechanism of the round pipe cutting device according to the present invention will be described. Knockout member 3 and the upper end of die 4 have an outer diameter of one round tube A to accommodate round tube A.
/ 2 is formed on a semi-cylindrical surface having a radius corresponding to / 2. The upper end of the die 4 is provided with the round tube A for securely receiving the round tube A.
Is extended slightly higher than a radius corresponding to one-half of the outer diameter of the rim. The left edge semicircle of the upper end of the die 4 is formed as a shearing blade. The upper end of the knockout member 3 is formed as a semi-cylindrical surface having a radius corresponding to 1/2 of the outer diameter of the round tube A and a predetermined axial length so as to support the round tube A, and a right end semicircular periphery. Is not formed as a shearing blade. A round tube A is accommodated above the die 4 and the knockout member 3 during shearing, and a slide punch 6 and a fixed punch 7 as a core metal are arranged in the round tube A. Above the round tube A, a punch 8 and a stripper 9 are arranged at positions corresponding to the knockout member 3 and the die 4 via a slide punch 6 and a fixed punch 7.

The shearing action of the round pipe by the shearing mechanism of the round pipe cutting apparatus according to the present invention will be described. The shearing blade of the shearing device for the round tube A is constituted by a semicircle at the right end of the lower end of the punch 8 and a circumferential edge at the left end of the fixed punch 7 for shearing the upper half of the round tube A. For the lower half shear,
It is composed of a combination of a left semicircular edge at the upper end of the die 4 and a right peripheral edge of the slide punch 6. Accordingly, the round pipe A is lowered by the lowering movement of the ram of the press machine (not shown) (downward stroke S; FIGS. 4A and 4C) by the lowering movement of the punch 8 fixed to the punch plate 11 of the base holder 12. The upper half is sheared by the cooperation of the right peripheral edge of the lower end of the punch 8 and the peripheral edge of the left end of the fixed punch 7, and the lower half of the round tube A is connected to the left peripheral edge of the upper end of the die 4. Is sheared by cooperation with the right peripheral edge of the slide punch 6. Punch 8 and fixed punch 7
The slide punch 6 that follows the downward movement of the punch 8 is slidably moved through the neck receiver 7a and the slide receiver 7b of the fixed punch 7 via the neck 6a and the slide 6b. By being fitted, a shearing motion is exerted by a relative motion between the punch 8 arranged with the precision shearing clearance and the fixed punch 7 which is not moved by the downward motion of the punch 8. On the other hand, slide punch 6 and die 4
Cooperates with the slide punch 6 descending with the punch 8.
The shearing motion is exerted by the relative motion between the slide punch 6 arranged with the precision shearing clearance and the die 4 which is not moved by the downward motion of the die. The click stop of the slide punch 6 is performed by a spring 22 in which a click stop pin 21 guided movably in the axial direction of the fixed punch 7 into a hole 7c of the fixed punch 7 is shown in FIG.
Of the click stop pin 21
Is performed by engaging the slide punch 6 movable in the direction perpendicular to the axial direction into the recess 6c at the upper end in FIG. 4D, and the click stop of the slide punch 6 is released by the click stop pin 21. The slide punch 6 is acted on by the engagement and disengagement from the recess 6c at the upper end in FIG. 4D, whereby the slide punch 6 and the fixed punch 7 are always aligned concentrically in the shear preparation position, that is, the mounting position of the round tube A. Is guaranteed. Further, after the slide punch 6 moves to the fixed punch 7 by the relative distance S during the shearing action of the round tube A (FIGS. 4A and 4C), after the round tube A is sheared,
When the knockout member 3 rises by the force of the spring 5 following the rise of the punch 8, the hole 7c of the fixed punch 7
A click stop pin 21, which is guided so as to be movable in the axial direction of the fixed punch 7, is moved by a spring 22 in FIG.
The depression 6c of the slide punch 6 is urged downward from (b).
, The slide punch 6 and the fixed punch 7 are again concentrically aligned. At this time, the knockout member 3 and the stripper 9 are simultaneously
And 10 are always biased upward and downward, so that the round tube A or the slide punch 6 and the fixed punch 7 are always
Therefore, the knockout member 3 moves up and down as the slide punch 6 rises, returning the sheared ring to a position concentric with the axis of the fixed punch 7.

The axial positioning of the round tube A and the ejection of the product (ring) after shearing will be described.

The charging of the round tube A is performed from the left side in FIG.
Ejection of the ring after shearing is performed again to the left in FIG. However, if necessary, the round tube A can be inserted from the right side in FIG. 2 and ejected in the leftward direction in FIG. According to the embodiment of FIG. 2, the right end of the round tube A is restricted in its axial position by the left end of the knockout 13. The left end position of the knockout 13 can be adjusted by using knockouts 13 of different lengths depending on the length of the ring sheared from the round tube A. The knockout 13 has a piston cylinder unit 2
Since the knockout operation rod 17 driven by 0 is connected, the axial position of the knockout 13 is regulated by the fixing plate 15. The axial position of the knockout 13 is important to obtain the desired exact dimension of the length of the ring to be sheared with the punch 8. The axial position of knockout 13 can be finely adjusted by piston cylinder unit 20. Ejection of each ring of a predetermined length, which occurs every time the round pipe A is sheared, fixes the knockout 13 via the knockout operating rod 17 by the operation of the piston cylinder unit 20.
2 to the left in FIG. 2 so as to protrude outwardly of the round tube cutting device according to the invention.

FIGS. 5 to 7 show a square tube cutting device as a second embodiment of the tube cutting device according to the present invention.

First, the overall configuration of the round tube cutting device will be described.

The base plate 31 can be fixed on a work table of a press machine (not shown). On the base plate 31, a shearing device for cutting the square tube B as a workpiece into a predetermined length is arranged. Back stopper 32 and die 34 fixed on base plate 31
And the knockout member 33 is fixed to the base plate 31 via two springs 35 disposed at regular intervals.
The knockout member 33 and the die 34
A slide punch 36 and a fixed punch 37 as a cored bar are arranged above, and a punch 38 and a stripper 39 are respectively arranged above them. The surfaces of the knockout member 33, the die 34, the slide punch 36, the fixed punch 37, the punch 38, and the stripper 39, which are in contact with the square tube B, are each approximately 4 with respect to the axial direction of the square tube B.
It has an inclination of 5 ° (FIG. 5). The upper surface of the stripper 39 is formed in a plane, and two springs 40 arranged at regular intervals are arranged on the upper surface of the stripper 39. The spring 40 is a punch plate that supports the punch 38. The spring 40 is housed in the hole 41.
The upper end of the spring 40 is supported by a base holder 42 fixed to a punch plate 41, and the lower end of the spring 40 is
9 is pressed downward. The base holder 42 is fixed to a drive ram of a press machine (not shown), and is driven to move up and down by the up and down movement of the drive ram. The square tube B to be cut is loaded into the shearing device from the left in FIG. 6, with the square tube B on the knockout member 33 and the die 34 via the slide punch 36 and the fixed punch 37 below and above the die. Similarly, the slide punch 36 and the fixed punch 3
7, and is held by the punch 38 and the stripper 39. At this time, a knockout 43 formed of a flange and a hollow tube is provided on the outer periphery of the fixed punch 37 to regulate the position of the square tube B in the axial direction and to eject a ring generated by cutting the square tube B. Along the axis of the tube B so that it can be displaced in the axial direction.

A fixed plate 45 is fixed on the base plate 31, and a fixed punch rod 37 ′ connected to a fixed punch 37 is supported on the fixed plate 45 and fixed by a stopper pin 46. The locking punch rod 37 ′ has a D-shaped cross section for detent and can be fitted in a correspondingly formed D-shaped hole of the fixing plate 45. On the other hand, the knockout 43 includes two knockout operation rods 47 which are arranged at a distance from each other.
And the knockout operation rod 47 is fixed to the fixing plate 45.
Are guided so as to be movable in the axial direction of the square tube B. The knockout operation rod 47 is driven by a piston cylinder unit 50 connected via a slide plate 48. The piston cylinder unit 50 is mounted on a cylinder table 49 welded on the base plate 31. The cylinder base 49 is fixed to the base plate 31 and is fixed to the base plate 31 from FIG.
And a portion that protrudes to the right of.

The configuration of the square tube shearing mechanism of the square tube cutting device according to the present invention will be described. The upper ends of the knockout member 33 and the die 34 are cut out in the form of a V-shaped groove having a size corresponding to a half of the rectangular cross section of the rectangular tube B for receiving the rectangular tube B (FIG. 5). The upper end of the die 34 is extended slightly higher than the dimension corresponding to one half of the rectangular cross section of the square tube B in order to securely receive the square tube B. The two left edges of the V-shaped groove at the upper end of the die 34 are formed as shearing blades. The upper end of the knockout member 33 is formed only as a V-shaped groove surface having a predetermined axial length so as to simply support the square tube B, and two edges of the right end V-shaped groove are not formed as shearing blades. . Die 34 and knockout member 3
A square pipe B is accommodated above the upper part 3 during processing, and a slide punch 36 and a fixed punch 37 as a metal core are arranged in the square pipe B. Above the square tube B, a punch 38 and a stripper 39 are disposed at positions corresponding to the knockout member 33 and the die 34 via a slide punch 36 and a fixed punch 37.

The shearing action of the square tube B by the shearing mechanism of the square tube cutting device according to the present invention will be described. The shearing blade of the shearing device for the square tube B is composed of a combination of two edges of the V-shaped groove at the lower end of the punch 38 and a rectangular cross-sectional edge at the left end of the fixed punch 37, and two edges of the V-shaped groove at the upper end of the die 34. It is composed of a combination of an edge and a rectangular cross-sectional edge at the right end of the slide punch 36. As a result, the ram is lowered by the ram of a press machine (not shown). [Downstroke S; operation state corresponding to FIGS. 4A and 4C of the first embodiment] Fixed to the punch plate 41 of the base holder 42. Due to the downward movement of the punch 38, the upper half of the square tube B
The two edges of the groove and the left edge of the fixed punch 37 are cooperatively sheared, while the lower half of the square tube B is the right edge of the slide punch 36 following the downward movement of the punch 38. Of the die 34 and the two edges of the V-shaped groove at the left end of the die 34 are sheared. The cooperation between the punch 38 and the fixed punch 37 is such that the slide punch 36 following the downward movement of the punch 38 is moved through the neck 36a and the sliding portion 36b to the neck receiver 37a and the slide receiver 3 of the fixed punch 37.
Punch 38 arranged with precision shearing clearance by being slidably precision fitted into 7b
A shearing motion is exerted by the relative motion between the fixed punch 37 and the stationary punch 37 which does not move. Meanwhile, the slide punch 36 and the die 34
The slide punch 36, which follows the downward movement of the punch 38, moves through the neck 36a and the sliding portion 36b of the fixed punch 37 via the neck receiving portion 37a and the sliding portion receiving portion 37b.
Slide punch 36 arranged with precision shearing clearance by being slidably fitted therein.
A shear motion is exerted by the relative motion between the fixed die 34 and the stationary die 34. The click stop of the slide punch 36 is performed by inserting the fixed punch 37 into the hole 37c of the fixed punch 37.
The click stop pin 51 guided movably in the axial direction is biased downward by a spring 52 [a configuration corresponding to FIG. 4B of the first embodiment]. This is performed by engaging a slide punch 36, which is arranged with a precision press clearance and is movable in a direction perpendicular to the axial direction, into a recess 36c at the upper end [FIGS. 4B and 4D of the first embodiment. )
The click stop release of the slide punch 36 is effected by the engagement and disengagement of the click stop pin 51 from the recess 36c at the upper end of the slide punch 36, whereby the shear preparation position, that is, the mounting position of the square tube B is set. Thus, it is guaranteed that the slide punch 36 and the fixed punch 37 are always aligned concentrically. Further, after the slide punch 36 moves to the fixed punch 37 by the relative distance S during the shearing action of the square tube B [FIG. 4 (a) of the first embodiment,
(Functional state corresponding to (c))] When the knockout member 33 rises by the force of the spring 35 following the rise of the punch 38 after the square tube B is sheared, the fixed punch 37 is inserted into the hole 37c of the fixed punch 37. The click stop pin 51 guided so as to be movable in the axial direction is urged downward by the spring 52 so that the depression 36 c of the slide punch 36 is formed.
[In accordance with FIGS. 4B and 4D of the first embodiment], the slide punch 36 and the fixed punch 37 are again aligned concentrically.
At this time, the knockout member 33 and the stripper 39 are simultaneously
Is always urged upward and downward by the springs 35 and 40, so that it always presses the square tube B or the slide punch 36 and the fixed punch 37. Therefore, the knockout member 33 is moved with the rise of the slide punch 36. Ascending and descending, the ring that has been sheared is returned to a position concentric with the axis of the fixed punch 37.

The positioning of the square tube B in the axial direction and the ejection of the product (ring) after shearing will be described.

The square tube B is inserted from the left in FIG.
Ejection of the ring after shearing is performed again to the left in FIG. However, it is also possible to insert the square tube B from the right direction in FIG. 6 and eject it in the left direction in FIG. 6 if necessary. According to the embodiment of FIG. 6, the right end of the square tube B is restricted in its axial position by the left end of the knockout 43. The left end position of the knockout 43 can be adjusted by using the knockout 43 having a different length depending on the length of the ring sheared from the square tube B. Knockout 43 includes piston cylinder unit 5
Since the knockout operation rod 47 driven by 0 is connected, the axial position of the knockout 43 is regulated by the fixing plate 45. The axial position of the knockout 43 is important to obtain the desired exact dimensions of the length of the ring to be sheared with the punch 38. The axial position of knockout 43 can be finely adjusted by piston cylinder unit 50. Ejection of each ring of a predetermined length that occurs each time the square tube B is sheared moves the knockout 43 to the left in FIG. 6 along the fixed punch 37 via the knockout operating rod 47 by the operation of the piston cylinder unit 50. This is achieved by projecting outwardly from the tube cutting device according to the invention.

Although the first embodiment has been described with reference to a round tube having a circular cross section as a round tube and the second embodiment has been described with respect to a tube having a rectangular cross section, the present invention is not limited to a perfect circle but may be applied to an elliptical tube. Obviously, it can be applied to a tube having a square cross section.

[Brief description of the drawings]

FIG. 1 is a front view of a round tube cutting type according to the present invention.

FIG. 2 is a partial cross-sectional side view of a round tube cutting mold according to the present invention.

FIG. 3 is a plan view of a round tube cutting mold according to the present invention.

FIGS. 4A and 4B show a punch acting as a core metal of a round tube cutting type according to the present invention, wherein FIG. 4A is a front view of a slide punch, FIG. 4B is a cross-sectional view thereof, and FIG. The front view and (d) are sectional views thereof.

FIG. 5 is a view showing a square tube cutting die according to the present invention, wherein (a) is a front view, (b) is a front view of the slide punch, and (c) is a plan view of the slide punch. FIG.

FIG. 6 is a partial sectional side view of a square tube cutting mold according to the present invention.

FIG. 7 is a plan view of a square tube cutting type according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Base plate 2 Back stop 3 Knockout member 4 Die 5 Spring 6 Slide punch 6a Neck 6b Sliding part 6c Depression 7 Fixed punch 7a Neck receiver 7b Sliding part receiver 7c Hole 8 Punch 9 Stripper 10 Spring 11 Punch plate 12 Base holder 13 Knockout 14 Bracket 15 Fixing plate 16 Stopper pin 17 Knockout operation rod 18 Slide plate 19 Cylinder base 20 Piston cylinder unit 21 Click stop pin 22 Spring 31 Base plate 32 Back stop 33 Knockout member 34 Die 35 Spring 36 Slide punch 36a Neck 36b Sliding portion 36c Recess 37 Fixed punch 37a Neck receiver 37b Sliding part receiver 37c Hole 37 'Fixed punch rod 38 Punch 39 Tripper 40 Spring 41 Punch plate 42 Base holder 43 Knockout 45 Fixing plate 46 Stopper pin 47 Knockout operation rod 48 Slide plate 49 Cylinder base 50 Piston cylinder unit 51 Stopper pin 52 Bracket A Round pipe A A 'Round pipe A (cutting position) B Square tube B B 'Square tube B (cutting position)

Claims (4)

[Claims] 1. A round tube cutting device, wherein a round tube shearing mechanism has a die (4) having a fixed position and an upper end of a knockout member (3) capable of moving up and down, each having a round tube (A).
Is formed as a semi-cylindrical surface having a radius corresponding to one-half of the outer diameter of the round tube (A), and the left end semicircle of the upper end of the die (4) is formed as a shear blade, and the knockout member ( The upper end of 3) is formed as a semi-cylindrical surface having a predetermined axial length so as to support the round tube (A), and the upper end of the die (4) and the knockout member (3) are provided with a round tube at the time of shearing. (A) is accommodated, and a slide punch (6) as a core metal and a fixed punch (7) for fixing the position are arranged in the round tube (A), and the right peripheral edge of the slide punch (6) and the fixed punch ( The left peripheral edge of 7) is formed as a shearing blade, and a slide punch (6) and a fixed punch (6) are provided above the round tube (A) at positions corresponding to the knockout member (3) and the die (4). Punch (8) and stripper (9) are arranged via 7) The lower end of the punch (8) is formed as a semi-cylindrical surface having a radius corresponding to one half of the outer diameter of the round tube (A), and the right end semicircle of the lower end is formed as a shearing blade. The lower end of 9) is formed as a semi-cylindrical surface having a predetermined axial length so as to press the round tube (A), and the right end semicircle of the punch (8) and the left end circle of the fixed punch (7). Periphery and slide punch (6)
The right edge of the die and the left edge of the die (4) are arranged with a precision shearing clearance from each other, and the punch (8) can be driven up and down by a driving device. The round tube cutting device according to claim 1, wherein the slide punch (6) is configured to move downward with the downward movement. 2. A neck portion (6a) formed at one end of a slide punch (6) and a sliding portion (6b) following the neck portion (6a) are connected to a neck receiver (7a) provided on a fixed punch (7). The sliding part (7b) is slidably fitted to each other, so that the slide punch (6) moves downward with respect to the fixed punch (7) with a fixed position together with the downward movement of the punch (8). The round tube cutting device according to claim 1, wherein 3. The square tube cutting device, wherein the square tube shearing mechanism comprises a die (34) and a top end of the knockout member (33) in which a rectangular cross section of the square tube (B) is received to receive the square tube (B). Of the size corresponding to the two adjacent sides of
The V-shaped groove at the upper end and the left end of the die (34) is formed as a shearing blade, and the upper end of the knockout member (33) is formed as an adjacent two-sided cross section of the square tube (B). It is formed as a V-shaped groove surface with dimensions corresponding to the sides,
Die (34) and knockout member (33) during shearing
A square punch (B) is accommodated above the slab, and a slide punch (36) as a core metal and a fixed punch (37) for fixing the position are arranged in the square tube (B), and the right end of the slide punch (36) is disposed. The rectangular cross-section edge and the left-hand rectangular cross-section edge of the fixed punch (37) are formed as shear blades, and the square tube (B)
Above the knockout member (33) and die (34)
At a position corresponding to the punch (38) and the stripper (3) via the slide punch (36) and the fixed punch (37).
9) are arranged, and two edges of the V-shaped groove at the right end of the punch (38) are formed as shear blades, and the punch (3) is formed.
8) Two edges of the V-shaped groove at the right end and the rectangular edge at the left end of the fixed punch (37), and two edges of the rectangular edge at the right end of the slide punch (36) and the V-shaped groove at the left end of the die (34). The peripheral edge is arranged with a precision shearing clearance from each other, and the punch (38) can be driven up and down by a driving device so that the slide punch (36) moves downward with the downward movement of the punch (38). The said square tube cutting apparatus characterized by the above-mentioned. 4. A neck portion (36a) formed at one end of a slide punch (36) and a sliding portion (36b) following the neck portion (36a).
The neck punch (37a) provided on the fixed punch (37) and the following slide portion receiver (37b) are slidably fitted to each other, whereby the slide punch (38) is moved together with the downward movement of the punch (38). 4. The tube cutting device according to claim 3, wherein the lower part moves downward relative to a fixed punch.