CN210908293U

CN210908293U - Round edge cutting device for end part of round pipe

Info

Publication number: CN210908293U
Application number: CN201922009001.3U
Authority: CN
Inventors: 毛小生; 潘其明; 李惠良; 毛寅生
Original assignee: Hangzhou Dacheng Metal Products Co ltd
Current assignee: Hangzhou Dacheng Metal Products Co ltd
Priority date: 2019-11-19
Filing date: 2019-11-19
Publication date: 2020-07-03
Anticipated expiration: 2029-11-19

Abstract

The utility model discloses a pipe tip circle of contact device belongs to cutting equipment's technical field, has solved among the prior art problem of the easy decentraction of radius that the same end major arc limit of pipe corresponds. The cutting device comprises a workbench, wherein an installation platform is arranged on the workbench, a placing groove for penetrating a circular tube is formed in the installation platform, and a cutting assembly for cutting a large arc edge and a small arc edge is arranged on the installation platform; the mounting table is provided with a through hole, the cutting assembly comprises an upper cutting part and a lower cutting part which are connected in the through hole in a sliding manner, and a driving part which drives the upper cutting part and the lower cutting part to lift and cut the circular tube; go up cutting portion including the butt in the last cutting block of pipe top, lower cutting portion is including wearing to locate the lower cutting block in the pipe, and the intercommunication has the shifting chute that supplies cutting block and lower cutting block to go up and down between standing groove and the through-hole, and drive division includes the second cylinder of being connected with last cutting block. The utility model discloses a cut from top to bottom, reduce the possibility of orthodrome limit radius decentraction.

Description

Round edge cutting device for end part of round pipe

Technical Field

The utility model relates to a cutting equipment's technical field, in particular to pipe tip circle limit device of cutting.

Background

In the prior art, a table and chair standing foot is formed by mutually sleeving and welding two hollow technical circular tubes, and arc edges are cut at two ends of the circular tubes sleeved outside.

As shown in fig. 1, two ends of the circular tube 10 are both cut with arc edges, and each end is cut with two opposite large arc edges 101, and the center of each large arc edge 101 is connected with a small arc edge 102; according to the design drawing, the radiuses of the two large arc edges 101 at the same end correspond to the same sphere center, so that the symmetry is guaranteed, and the strength and the stability of the welded circular tube 10 are good. In actual operation, one large circular arc edge 101 is cut, and then the circular tube 10 is turned over to cut the other large circular arc edge 101.

In the prior art, the two large arc edges are cut successively, so that the radii of the two opposite large arc edges at the same end are not concentric easily, and the quality of subsequent products is influenced.

SUMMERY OF THE UTILITY MODEL

The utility model aims at overcoming the not enough of the easy decentraction of radius that the big circular arc limit of same end of pipe corresponds among the prior art, and provide a pipe tip circle of contact device, reduce the possibility of big circular arc limit radius decentraction.

The above technical purpose of the present invention can be achieved by the following technical solutions:

a circular edge cutting device for the end part of a circular tube comprises a workbench, wherein an installation platform is arranged on the workbench, a placing groove for penetrating the circular tube is formed in the installation platform, and a cutting assembly for cutting a large circular edge and a small circular edge is arranged on the installation platform; the mounting table is provided with a first through hole which penetrates through the mounting table in the thickness direction and is communicated with the placing groove, the cutting assembly comprises an upper cutting part and a lower cutting part which are connected in the through hole in a sliding mode and mutually abutted, and a driving part which drives the upper cutting part and the lower cutting part to lift and cut the circular tube; the upper cutting part comprises an upper cutting block abutted to the upper part of the circular tube, the lower cutting part comprises a lower cutting block penetrating through the circular tube, and the projections of the upper cutting block and the lower cutting block in the vertical direction are overlapped; a moving groove for lifting the upper cutting block and the lower cutting block is communicated between the placing groove and the through hole, and the upper cutting block and the lower cutting block extend into the moving groove; the driving part comprises a second air cylinder connected with the upper cutting block.

By adopting the technical scheme, one end of the circular tube is inserted into the placing groove, the lower cutting block is positioned in the circular tube, and the upper cutting block is positioned above the circular tube; go up butt portion and butt portion butt each other down, when butt portion descended in the cylinder drive, butt portion received the power of butt portion also downstream down, goes up butt cutting block and cuts first one with the pipe, and lower cutting block cuts the pipe lower half, goes up the projection coincidence of cutting block and lower cutting block in vertical direction, has guaranteed that two great arcs of pipe same end are identical and longitudinal symmetry. According to the scheme, the two cutting blocks aligned in the vertical direction are utilized to cut the circular tube, and the two arc edges at the same end are cut simultaneously, so that the concentricity accuracy of the corresponding radii of the large arc edges is greatly improved, and the product quality is improved; meanwhile, one end of the cutting tool only needs to be cut once, so that the cutting times are reduced, and the production efficiency is improved.

More preferably: the mounting table comprises an upper mounting plate and a lower mounting plate, and the upper mounting plate and the lower mounting plate divide the placing groove into an upper part and a lower part; the lower mounting plate is provided with a positioning hole, and the upper mounting plate is fixed with a positioning column with one end extending into the positioning hole.

By adopting the technical scheme, the mounting table is arranged into two detachable parts, the mounting table is detached to observe the placing groove, the mounting table and the cutting block are convenient to maintain and replace, and the cutting part is convenient to install. The positioning between the upper mounting plate and the lower mounting plate can be realized through the positioning hole and the positioning column, so that the through holes of the two parts are communicated.

More preferably: the upper cutting part further comprises an upper connecting block fixedly connected with the upper cutting block, the lower cutting part further comprises a lower connecting block fixedly connected with the lower cutting block, the upper connecting block and the lower connecting block are slidably connected in the through hole, the driving part comprises a first air cylinder connected with the upper connecting block, and the upper connecting block and the lower connecting block are arranged close to the outer wall surface of the lower cutting block and at intervals with the inner wall surface of the through hole.

By adopting the technical scheme, the lower cutting block and the lower cutting block are small in size, are directly connected in the through hole in a sliding manner, and are unstable in sliding path and easy to turn over. The upper connecting block and the lower connecting block increase the overall weight of the upper cutting part and the lower cutting part, the upper connecting block and the lower connecting block slide more stably in the through hole, and meanwhile, the overall volume of the upper cutting part and the lower cutting part is increased, so that the moving track of the upper cutting part and the lower cutting part is convenient to observe; on the other hand, except the descending driving of the upper cutting part and the lower cutting part by the cylinder, the self weight of the upper connecting block and the lower connecting block also provides cutting force for cutting the circular tube, and the cutting efficiency is improved. The scraps may fall from the gaps between the upper and lower connection blocks and the inner wall surface of the through-hole.

More preferably: an auxiliary plate is fixed at the port of the through hole far away from the upper cutting block, and the inside of the through hole on the auxiliary plate extends; the driving part also comprises a plurality of return springs fixedly connected between the auxiliary plate and the lower connecting block.

Adopt above-mentioned technical scheme, after the cutting, take out the ring, the cylinder output shaft withdrawal will be gone up the connecting block and upwards driven, and reset spring loses the pressure of cylinder, resets gradually, will descend the connecting block to reset, can directly insert the standing groove with next pipe and cut.

More preferably: auxiliary plates are arranged on two sides of the length direction of the placing groove.

By adopting the technical scheme, the two sides of the lower connecting block can be uniformly reset by the restoring force of the spring, so that the moving stability of the lower connecting block in the through hole is improved, and the possibility of inclination is reduced.

More preferably: a connecting plate is connected between the lower mounting plate and the workbench, the through hole penetrates through the mounting plate, one end of an extension plate is fixed on the connecting plate, the extension plate extends to the outer side of the lower mounting plate, and the extension direction of the extension plate is parallel to the length direction of the placing groove; one end of the extension plate, which is far away from the lower mounting plate, is fixed with a bearing block for supporting a round pipe, a locating rod is fixed on the bearing block, and the end part of the round pipe is abutted against the outer wall surface of the locating rod.

By adopting the technical scheme, the connecting plate realizes the connection among the mounting table, the workbench and the extension plate; during cutting, one end of the circular tube is placed in the placing groove of the lower mounting plate, and the other end of the circular tube is abutted to the outside of the positioning column, so that the circular tube is positioned in the length direction.

More preferably: the cross section of the positioning rod is circular, and the outer wall surface of the positioning column is matched and abutted with the large arc radian.

By adopting the technical scheme, when a single circular tube is cut for the second time, the cut large circular arc edge is abutted to the positioning column, so that positioning is realized, the possibility of rotation of the circular tube in the placing groove is reduced, and the stability of the pipeline during cutting is improved.

More preferably: and a lug which is matched with the radian of the small arc and is abutted against the radian of the small arc is fixed on the positioning rod.

By adopting the technical scheme, when a single circular tube is cut for the second time, the large arc edge and the small arc edge which are already cut are abutted against the positioning column and the lug, so that the positioning is realized, meanwhile, the possibility of rotation of the circular tube in the placing groove is reduced, and the stability of the pipeline during cutting is improved.

More preferably: a stop block is fixed on the surface of the lower mounting plate, on which the lower cutting block is fixed, and extends in parallel with the lower cutting block; when the lower cutting block is sleeved with the round pipe, the end face of the round pipe is abutted to the stop block.

By adopting the technical scheme, the end face of the circular tube is abutted against the stop block, the relative position between the lower cutting block and the circular tube is limited, the length of the lower cutting block is limited, the radius of the large arc edge is determined, and the large arc edge with the same radius can be obtained after each cutting.

More preferably: the cross section of the moving groove is the same as the shape of the round pipe needing to be cut, and when the lower cutting block is positioned in the moving groove below the placing groove, the outer wall surface of the lower cutting block is abutted against the inner wall surface of the moving groove.

By adopting the technical scheme, the part of the moving groove is just filled by the lower cutting block, and when the lower cutting block is cut, the lower cutting block and the moving groove generate opposite shearing force to shear the circular tube, so that the shearing effect is improved.

To sum up, the utility model discloses following beneficial effect has:

1. by arranging the lower cutting part, the upper cutting part and the driving part, the driving part is used for driving the lower cutting part and the upper cutting part to cut downwards, so that the cutting of two large arc edges and two small arc edges is finished at one time, the accuracy of the large arc edges in concentricity with the corresponding radius is greatly improved, and the product quality is improved; meanwhile, one end only needs to be cut once, so that the cutting times are reduced, and the production efficiency is improved;

2. by arranging the upper mounting plate, the lower mounting plate, the upper connecting block and the lower connecting block, the components are convenient to mount and replace, and the stability of the lower cutting part and the lower cutting part moving in the through hole is improved;

3. the lower connecting block is automatically reset by arranging the auxiliary plate and the reset spring, so that continuous cutting operation is facilitated;

4. through setting up reference column and lug, when single pipe was cut for the second time, will cut the big arc limit and the little arc limit butt of accomplishing on reference column and lug, realize the location, simultaneously, reduce the pipe pivoted possibility in the standing groove, the stability of pipeline when improving the cutting.

Drawings

FIG. 1 is a schematic structural view of a prior art round tube;

FIG. 2 is a schematic view of the present invention and a circular tube;

FIG. 3 is a top view of FIG. 2;

FIG. 4 is a partial cross-sectional view of section A-A of FIG. 3;

fig. 5 is an exploded view of the mounting table, connecting plate, extension plate, bearing block, locating post, projection and tube.

Reference numerals: 1. a work table; 11. a table body; 111. a discharge channel; 12. erecting a rod; 13. a top plate; 2. an installation table; 21. an upper mounting plate; 211. a positioning column; 212. a chute; 22. a lower mounting plate; 221. positioning holes; 23. a placement groove; 24. a through hole; 241. a first hole portion; 242. a second hole portion; 25. a moving groove; 3. a connecting plate; 4. a cutting assembly; 5. an upper cutting part; 51. an upper connecting block; 511. a slider; 52. an upper cutting block; 6. a lower cutting section; 61. a lower connecting block; 62. a lower cutting block; 63. a stopper; 7. a drive section; 71. a first cylinder; 72. a second cylinder; 73. an auxiliary plate; 74. a return spring; 8. an extension plate; 9. a bearing block; 91. positioning a rod; 92. a bump; 10. a circular tube; 101. a large circular arc edge; 102. a small arc edge.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings.

For convenience of illustration, the circular tube 10 is introduced in the present embodiment, as shown in fig. 1, each end of the circular tube 10 is cut with two opposite large arc edges 101, and a small arc edge 102 is connected to the center of each large arc edge 101.

A round edge cutting device for the end part of a round pipe 10 is shown in figure 2 and comprises a workbench 1, a connecting plate 3 fixed with the workbench 1 through bolts, a mounting table 2 fixed on the upper surface of the connecting plate 3, and a cutting assembly 4 arranged on the mounting table 2.

The workbench 1 comprises a workbench body 11, four upright rods 12 vertically fixed on the upper surface of the workbench body 11, and a top plate 13 horizontally fixed on the upper end surfaces of the four upright rods 12, wherein the cross section of the workbench body 11 is rectangular, and the upright rods 12 are arranged at four end corners of the workbench body 11. The connecting plate 3 is fixed on the upper surface of the table body 11.

As shown in fig. 3 and 4, the mounting platform 2 is rectangular, a placing groove 23 with a cross section being circular and used for penetrating through the circular tube 10 is horizontally arranged on the mounting platform 2, a through hole 24 with two through ends is vertically arranged, the through hole 24 is arranged at the center of the horizontal plane of the mounting platform 2, one end of the placing groove 23 is communicated with the through hole 24, and the other end of the placing groove is communicated with the mounting platform 2.

As shown in FIG. 4, the lower end of the through hole 24 extends into the table body 11 through the connecting plate 3, the lower end of the through hole 24 is communicated with a discharge channel 111 opened on the table body 11, and the other end of the discharge channel 111 extends obliquely downwards and penetrates through the table body 11. The through hole 24 includes a first hole portion 241 and a second hole portion 242 having a rectangular cross section, the second hole portion 242 communicates between the first hole portion 241 and the placement groove 23, and a long side and a width of the cross section of the second hole portion 242 are respectively smaller than a long side and a wide side of the first hole portion 241.

As shown in fig. 5, the mounting table 2 includes a lower mounting plate 22 fixed to the connecting plate 3, and an upper mounting plate 21 located above the lower mounting plate 22, positioning holes 221 having a circular cross section are formed at four corners of the upper surface of the lower mounting plate 22, and four positioning posts 211 corresponding to the four positioning holes 221 are fixed to the lower surface of the upper mounting plate 21. The upper mounting plate 21 and the lower mounting plate 22 divide the through-hole 24 and the placement groove 23 into upper and lower two parts.

The cutting assembly 4 includes upper and

lower cutting portions

5 and 6 provided in the through-hole 24, and a driving portion 7 driving the upper and

lower cutting portions

5 and 6 to ascend and descend. The upper cutting part 5 includes an upper connecting block 51 slidably coupled in the first hole part 241, and an upper cutting block 52 horizontally fixed to the upper connecting block 51, and the lower cutting part 6 includes a lower connecting block 61 slidably coupled in the first hole part 241, and a lower cutting block 62 horizontally fixed to the lower connecting block 61.

The lower end face of the upper cutting block 52 is flush with the lower surface of the upper connecting block 51, the lower end face of the lower cutting block 62 is flush with the lower surface of the lower connecting block 61, and the lower surface of the upper connecting block 51 is abutted against the upper surface of the lower connecting block 61. The end surfaces of the lower cutting block 62 and the lower cutting block 62 far away from the upper connecting block 51 and the lower connecting block 61 are correspondingly matched with the large arc edge 101 and the small arc edge 102 in shape. The upper connecting block 51 is slidably connected to the first portion of the hole of the upper mounting plate 21, and the lower connecting block 61 is slidably connected to the first portion of the holes of the upper connecting block 51 and the lower connecting block 61.

A vertically-arranged moving groove 25 is communicated between the placing groove 23 and the second hole part 242, and the cross section of the moving groove 25 is the same as the projections of the large arc edge 101 and the small arc edge 102 on the horizontal plane and is used for penetrating through the upper cutting block 52 and the lower cutting block 62; the upper end of the moving groove 25 penetrates the upper mounting plate 21, and the lower end penetrates the connecting plate 3. The lower cutting block 62 and the lower cutting block 62 extend into the moving groove 25 through the second hole portion 242, and when the upper cutting block 52 and the lower cutting block 62 are not in the placement groove 23, the end surfaces of the upper cutting block 52 and the lower cutting block 62 away from the upper connection block 51 and the lower connection block 61 abut against the inner wall surface of the moving groove 25. The upper end groove of the discharging passage 111 communicates with the lower end of the second hole portion 242.

The upper cutting block 52 and the lower cutting block 62 are respectively fixed with a stop block 63, the stop block 63 extends along the horizontal direction, and one end of the horizontal direction is fixed with the lower connecting block 61. When the cutting device is used, the circular tube 10 is positioned in the placing groove 23 and sleeved outside the lower cutting block 62, the end surface of the circular tube abuts against the end surface of the stop block 63 of the lower cutting block 62, and the upper cutting block 52 is positioned above the circular tube 10.

An auxiliary plate 73 is fixed to the inner wall surface of the through hole 24, the auxiliary plate 73 is flush with the lower surface of the lower mounting plate 22 and is positioned below the lower connecting block 61, and the auxiliary plate 73 extends into the through hole 24. The driving part 7 includes a first cylinder 71 (see fig. 2) driving the upper connection block 51 to ascend and descend, a second cylinder 72 (see fig. 2) driving the upper connection block 51 to ascend and descend, and a return spring 74 connected between the lower connection block 61 and the auxiliary plate 73. The auxiliary plates 73 are provided in two pieces and located on both sides of the placement groove 23 in the longitudinal direction, and two return springs 74 are fixed to each auxiliary plate 73.

As shown in fig. 2, a first cylinder 71 and a second cylinder 72 are fixed on the top plate 13, two first cylinders 71 are provided and are respectively fixed on the upper mounting plate 21 at both sides of the upper connecting block 51, and the second cylinder 72 is provided between the two first cylinders 71 and has its output shaft aligned with the upper connecting block 51.

As shown in fig. 5, the upper mounting plate 21 is provided with a sliding groove 212, the upper connecting block 51 is provided with a sliding block 511 engaged with the sliding groove 212, the upper end of the sliding groove 212 penetrates through the lower end thereof, and the lower end of the sliding groove 212 extends to the lower side of the placing groove 23 of the upper mounting plate 21. The motion of first cylinder 71 can drive the lift of connecting block 51, goes up connecting block 51 and connecting block 61 butt back down, starts second cylinder 72 and descends to connecting block 51 and lower connecting block 61 butt on going up, realizes the cutting of going up cutting block 52 and lower cutting block 62.

One end of an extension plate 8 is horizontally fixed on the connecting plate 3, the other end of the extension plate 8 extends out of the table body 11 along the length direction of the placing groove 23, and the extension plate 8 is arranged on one side of the placing groove 23 penetrating through the mounting table 2. A bearing block 9 is fixed on the upper surface of one end of the extension plate 8, which is far away from the mounting table 2, and a positioning rod 91 with a circular cross section is vertically fixed on the bearing block 9 and matched with a large arc edge 101 of the circular tube 10; a protrusion 92 is fixed on one side of the positioning rod 91 close to the mounting block, and the protrusion 92 is matched with the small arc edge 102.

When a single circular tube 10 is cut for the second time, the cut large arc edge 101 and the cut small arc edge 102 are abutted to the positioning column 211 and the bump 92, so that positioning is realized, and meanwhile, the length of the circular tube 10 is determined.

The implementation principle of the embodiment is as follows: starting the first air cylinder 71, lifting the upper mounting plate 21, placing one end of the circular tube 10 into the placing groove 23 and sleeving the circular tube outside the lower cutting block 62, abutting the other end of the circular tube outside the bump 92, starting the first air cylinder 71 to descend the upper mounting plate 21 until the circular tube is abutted with the lower mounting plate 22, and then starting the second air cylinder 72 to descend the upper connecting block 51 until the upper cutting block 52 and the lower cutting block 62 cut the circular tube 10; after the cutting is completed, the first cylinder 71 and the second cylinder 72 are lifted, the round tube 10 is taken out, the cut end is abutted to the outside of the positioning rod 91 and the bump 92, the uncut round tube is placed in the placing groove 23, and the above operations are repeated to complete the cutting. And after one round pipe 10 is finished, cutting the round pipe 10.

The present embodiment is only for explaining the present invention, and it is not limited to the present invention, and those skilled in the art can make modifications to the present embodiment without inventive contribution as required after reading the present specification, but all of them are protected by patent laws within the scope of the claims of the present invention.

Claims

1. A circular tube end portion round edge cutting device comprises a workbench (1), and is characterized in that an installation table (2) is arranged on the workbench (1), a placing groove (23) used for penetrating through a circular tube (10) is formed in the installation table (2), and a cutting assembly (4) used for cutting a large circular arc edge (101) and a small circular arc edge (102) is arranged on the installation table (2); a through hole (24) which penetrates through the mounting table (2) in the thickness direction and is communicated with the placing groove (23) is formed in the mounting table, the cutting assembly (4) comprises an upper cutting part (5) and a lower cutting part (6) which are connected in the through hole (24) in a sliding mode and mutually abutted, and a driving part (7) which drives the upper cutting part (5) and the lower cutting part (6) to lift and cut the circular tube (10); the upper cutting part (5) comprises an upper cutting block (52) abutted to the upper part of the circular tube (10), the lower cutting part (6) comprises a lower cutting block (62) penetrating through the circular tube (10), and the projections of the upper cutting block (52) and the lower cutting block (62) in the vertical direction are overlapped; a moving groove (25) for lifting the upper cutting block (52) and the lower cutting block (62) is communicated between the placing groove (23) and the through hole (24), and the upper cutting block (52) and the lower cutting block (62) extend into the moving groove (25); the drive section (7) includes a second cylinder (72) connected to the upper cutting block (52).

2. The round pipe end edge trimming device according to claim 1, wherein the mounting table (2) comprises an upper mounting plate (21) and a lower mounting plate (22), and the upper mounting plate (21) and the lower mounting plate (22) divide the placing groove (23) into an upper part and a lower part; a positioning hole (221) is formed in the lower mounting plate (22), and a positioning column (211) with one end extending into the positioning hole (221) is fixed on the upper mounting plate (21).

3. The round pipe end edge trimming device according to claim 1, wherein the upper cutting part (5) further comprises an upper connecting block (51) fixedly connected with the upper cutting block (52), the lower cutting part (6) further comprises a lower connecting block (61) fixedly connected with the lower cutting block (62), the upper connecting block (51) and the lower connecting block (61) are slidably connected in the through hole (24), the upper connecting block (51) and the lower connecting block (61) are arranged at intervals close to the outer wall surface of the lower cutting block (62) and the inner wall surface of the through hole (24), and the driving part (7) comprises a first air cylinder (71) connected with the upper connecting block (51).

4. The round pipe end edge cutting device as claimed in claim 3, characterized in that an auxiliary plate (73) is fixed to the port of the through hole (24) far away from the upper cutting block (52), and the auxiliary plate (73) extends inside the through hole (24); the driving part (7) also comprises a plurality of return springs (74) fixedly connected between the auxiliary plate (73) and the lower connecting block (61).

5. Round pipe end trimming device according to claim 4, characterized in that the placing groove (23) is provided with auxiliary plates (73) on both sides in the length direction.

6. The round pipe end edge cutting device according to claim 2, wherein a connecting plate (3) is connected between the lower mounting plate (22) and the workbench (1), a through hole (24) penetrates through the mounting plate, one end of an extending plate (8) is fixed on the connecting plate (3), the extending plate (8) extends towards the outer side of the lower mounting plate (22), and the extending direction of the extending plate (8) is parallel to the length direction of the placing groove (23); one end of the extension plate (8) far away from the lower mounting plate (22) is fixed with a bearing block (9) used for supporting the round pipe (10), a positioning rod (91) is fixed on the bearing block (9), and the end part of the round pipe (10) is abutted against the outer wall surface of the positioning rod (91).

7. The round tube end trimming device according to claim 6, wherein the cross section of the positioning rod (91) is circular, and the outer wall surface of the positioning column (211) is in arc fit with and abutted against a large arc.

8. The round tube end edge trimming device according to claim 7, wherein the positioning rod (91) is fixed with a projection (92) which is matched with the small arc and is abutted against the small arc.

9. The round pipe end edge trimming device according to claim 2, wherein a stopper (63) is fixed on the surface of the lower mounting plate (22) on which the lower cutting block (62) is fixed, and the stopper (63) extends in parallel with the lower cutting block (62); when the round tube (10) is sleeved outside the lower cutting block (62), the end surface of the round tube (10) is abutted against the stop block (63).

10. The round pipe end edge trimming device according to claim 1, wherein the cross section of the moving groove (25) is the same as the shape of the round pipe (10) to be trimmed, and when the lower cutting block (62) is located in the moving groove (25) below the placing groove (23), the outer wall surface of the lower cutting block (62) abuts against the inner wall surface of the moving groove (25).