CN107442639B

CN107442639B - Close tooth type retractable inner shaft mechanism for pipe punching

Info

Publication number: CN107442639B
Application number: CN201710709059.1A
Authority: CN
Inventors: 倪正中; 方勇
Original assignee: Taizhou Zhongrui Electronics Co ltd
Current assignee: Taizhou Zhongrui Electronics Co ltd
Priority date: 2017-08-17
Filing date: 2017-08-17
Publication date: 2023-04-14
Anticipated expiration: 2037-08-17
Also published as: CN107442639A

Abstract

The invention discloses a dense-tooth type retractable inner shaft mechanism for punching pipes, which comprises an upper die, a punch arranged on the upper die, an arc-shaped groove arranged on a lower die and the lower die, wherein an outer guide pillar is fixed on the lower die, the outer guide pillar is sequentially sleeved with a floating seat and an outer guide sleeve which are connected with each other, the free end of the outer guide pillar is connected with an outer connecting plate, a floating seat spring is arranged between the floating seat and the lower die, the floating seat is provided with a crescent groove, an inner shaft mechanism is arranged in the crescent groove, the crescent groove is fixedly provided with an inner guide pillar, the inner guide pillar is sleeved with an inner guide sleeve fixed on an upper shaft joint, the inner guide pillar is connected with an inner connecting plate, a shaft lowering spring is arranged between the inner guide sleeve and the inner connecting plate, a cam groove is arranged in the lower shaft joint, a driving rod matched with the cam groove is fixed on the upper die, an inclined part is arranged on the arc-shaped groove, the pin groove is sequentially connected with a floating pin spring and a floating pin, the upper die is fixed with a prepressing seat, the prepressing seat is provided with a pressure rod, and the inner shaft can automatically complete the action, and is labor-saving and high-efficiency; the inner shaft can be freely spliced, so that the processing difficulty and the cost are low; the taking and the placing are convenient.

Description

Close-tooth type retractable inner shaft mechanism for pipe punching

Technical Field

The invention belongs to the field of pipe reprocessing equipment, and particularly relates to a dense-tooth type retractable inner shaft mechanism for pipe punching.

Background

The existing technical scheme is that an inner shaft is divided into an upper half shaft and a lower half shaft, a combination surface of the upper half shaft and the lower half shaft is a whole inclined surface, after the tube is punched, the lower half shaft needs to be completely pulled out of a finished tube by one person, and the finished tube can be pulled out by the other person, so that the labor cost is high, and the labor intensity is high; the inner shaft needs to be drawn out for occupying extra time and needs to be reset additionally, the inner shaft is worn quickly, the pipe is easy to scratch, the production efficiency is reduced, and the quality of a finished product is unstable.

Disclosure of Invention

The invention aims to provide a dense-tooth type retractable inner shaft mechanism for punching pipes, wherein the movement of an inner shaft is synchronously and automatically completed in the working process of a die, so that one person for pulling out the inner shaft can be saved, the labor cost is saved, and the production efficiency is improved; the inner shaft is not easy to wear and has long service life, and the finished product has stable quality; the length of the inner shaft can be freely spliced in sections according to the length of the processed pipe, so that the processing difficulty and the processing cost of the inner shaft are greatly reduced, and the adaptability to the length of a product is high; the whole inner shaft mechanism can float up and down, and the pipe taking and placing are convenient.

The main technical solution of the present invention is to provide a dense-teeth type retractable inner shaft mechanism for punching pipes, which comprises an upper die, a punch arranged on the upper die, a lower die and an arc-shaped groove arranged on the lower die, wherein an outer guide post is fixed on the lower die, a floating seat and an outer guide sleeve which can move up and down are sequentially sleeved on the outer guide post from bottom to top, the outer guide sleeve is connected and fixed with the floating seat, the free end of the outer guide post is connected with an outer connecting plate, a floating seat spring sleeved on the outer guide post is arranged between the bottom of the floating seat and the lower die, the floating seat is provided with a crescent groove which is close to and coaxial with the arc-shaped groove, a lower shaft joint which can move left and right along the axial direction of the crescent groove is arranged in the crescent groove, an upper shaft joint is arranged at the top of the lower shaft joint, a lower shaft and a lower shaft are connected at one end close to the arc-shaped groove in sequence, and an upper shaft head are connected at one end close to the arc-shaped groove in sequence, the floating seat is provided with an inner guide post which sequentially penetrates through the upper shaft joint and the lower shaft joint to be fixed at the bottom of the crescent moon groove, an inner guide sleeve which is fixed at the top of the upper shaft joint and can move up and down along the inner guide post is sleeved on the inner guide post, the free end of the inner guide post is connected with an inner connecting plate, a shaft descending spring which is sleeved on the inner guide post is arranged between the inner guide sleeve and the inner connecting plate, a cam groove is arranged in the lower shaft joint, the inner connecting plate, the upper shaft joint, the floating seat and the lower die are respectively provided with a through hole corresponding to the cam groove, the four through holes and the cam groove together form a rod channel, a driving rod of which the upper end is fixed on the upper die is sleeved in the rod channel, the driving rod is provided with an inclined part which can be matched with the cam groove to drive the lower shaft joint to move left and right, the top of the lower shaft and the bottom of the upper shaft are respectively provided with a tooth groove mechanism formed by a plurality of tooth projections and a plurality of grooves at intervals, the arc groove is provided with a pin groove, the bottom of the floating pin spring and a prepressing seat is sequentially connected with the floating pin spring and the floating pin, a pressure rod capable of moving up and down is sleeved in the prepressing seat, and a pressure seat spring is arranged between the prepressing seat and the top of the pressure rod.

The pin groove consists of a pin hole and a screw plug at the bottom of the pin hole, the top of the floating pin is an inclined plane which is close to the lower shaft and is higher at one side, the upper part of the floating pin supports the lower shaft under the elastic force action of a spring of the floating pin, and when workpiece round tubes are sleeved outside the upper shaft and the lower shaft, the upper part of the floating pin supports the workpiece round tubes.

When the upper die drives the driving rod to lift up and down, the inclined part of the driving rod is matched with the wall of the cam groove to push the lower shaft joint to move left and right, so that the lower shaft rigidly connected with the lower shaft joint moves left and right in the arc-shaped groove of the lower die.

A buffer ring sleeved on the outer guide pillar is arranged between the outer guide sleeve and the outer connecting plate, so that collision impact between the outer guide sleeve and the outer connecting plate is reduced, and the service life is prolonged.

The upper die is fixed with four outer guide columns on the lower die, the floating seat is sleeved on the four outer guide columns at the same time, two free ends on the same sides of the free ends of the four outer guide columns are connected to two outer connecting plates respectively as a group, two pressing rods capable of moving up and down are sleeved in the prepressing seat, the two outer connecting plates are provided with notches for the pressing rods to pass through, front cover strips fixed on the lower die are arranged on the front side and the rear side of the floating seat respectively, side cover strips fixed on the lower die are arranged on the left side and the right side of the floating seat respectively, the pressing rods are driven to lift up and down when the upper die lifts up and down, the floating seat is pushed by a floating seat spring, and the floating seat, together with the outer guide sleeve and parts mounted on the floating seat, can float up and down along the outer guide columns.

And a supporting column for reinforcing is connected between the inner connecting plate and the floating seat.

A spring seat sleeved on the inner guide post is arranged between the inner guide sleeve and the shaft lowering spring, so that the spring force applied to the inner guide sleeve is more uniform and stable.

The pipe length that can process as required between lower coupling and the lower spindle nose connects a plurality of lower axles, can process as required between the upper coupling and the upper spindle nose connects a plurality of upper shafts, and the upper shaft top end face evenly is equipped with a plurality of semicircular backing sheets.

The upper shaft and the upper shaft joint, the upper shaft and the upper shaft head, the lower shaft and the lower shaft head are fixed through screws and cylindrical pins, the inner shaft mechanism comprises an upper shaft joint arranged on the lower shaft joint and the lower shaft joint, the lower shaft joint is sequentially connected with the lower shaft and the lower shaft head, and the upper shaft joint is sequentially connected with the upper shaft and the upper shaft head.

And (3) implementing an action process: a circular tube penetrates through the upper shaft head and the lower shaft head from right to left, the left end face side of the circular tube pushes the inclined surface of the floating pin to compress a spring of the floating pin, the upper surface of the floating pin supports the lower surface of the circular tube, the lower part of the inner surface of the circular tube is attached to the lower surface of the lower shaft, after the circular tube is pushed in place leftwards, the upper die moves downwards, the pressure rod penetrates through the notch to press the floating seat, the floating seat moves downwards to compress the spring of the floating seat, the pressure rod pushes the pressing seat spring at the upper part to compress, and the bottom of the floating seat stops when contacting with the lower die; at the moment, the upper die continues to move downwards, the pressure rod continues to push the pressure seat spring at the upper part to compress, the left side inclined plane of the inclined part of the drive rod contacts the left side inclined plane of the lower shaft joint cam groove to push the lower shaft joint and the rigidly connected lower shaft to move left, the tooth projection in the tooth groove mechanism at the upper part of the lower shaft is changed from being matched with the upper shaft groove to being matched with the tooth projection of the upper shaft, and then the upper shaft moves upwards until the outer surface of the upper shaft tightly supports the inner surface of the circular tube; at the moment, the upper die continues to move downwards, the punch arranged on the upper die enters a gap between two adjacent supporting sheets, and the circular tube starts to be punched, so that a groove is cut on the circular tube; then the upper die starts to move upwards, and the punch is separated from the circular tube along with the upper die; the upper die continues to move upwards, the right inclined surface of the inclined part of the driving rod contacts the right inclined surface of the lower shaft joint cam groove to push the lower shaft which is connected with the lower shaft joint and the lower shaft which is connected with the lower shaft joint in a rigid mode to move rightwards, the upper shaft joint, the upper shaft and the inner guide sleeve move downwards along the inner guide pillar under the action of the elastic force of the shaft lowering spring, and the tooth projection in the tooth groove mechanism at the bottom of the upper shaft is matched with the tooth projection of the lower shaft from the previous time to the groove of the lower shaft, so that the surface of the upper shaft and the inner surface of the circular tube are in a loosened state; the upper die continues to move upwards, the lower part of the compression rod is separated from the upper part of the floating seat, a compression seat spring on the upper part of the compression rod is restored to an initial state, the floating seat floats to the upper part of the buffer ring and is attached to the outer connecting plate under the action of the spring force of the floating seat spring, the floating seat stops when floating upwards and floats together with the lower shaft joint, the lower shaft and the upper shaft, the lower surface of the circular tube is separated from the inner wall of the arc-shaped groove of the lower die, the upper die continues to move upwards until the upper dead center of the upper die stops, then the finished circular tube is manually pulled out rightwards, and the floating pin rises under the spring force of the floating pin spring to support the lower shaft, so that a working cycle is completed.

The invention has the beneficial effects that: the movement of the inner shaft is synchronously and automatically completed in the working process of the die, so that one person for pulling the inner shaft can be saved, the labor cost is saved, and the production efficiency is improved; the inner shaft is not easy to wear and has long service life, and the finished product has stable quality; the length of the inner shaft can be freely spliced in sections according to the length of the processed pipe, so that the processing difficulty and the processing cost of the inner shaft are greatly reduced, and the adaptability to the length of a product is high; the whole inner shaft mechanism can float up and down, and the pipe taking and placing are convenient.

Drawings

Figure 1 is a schematic structural view of an embodiment of the present invention,

figure 2 is a cross-sectional view of the embodiment of figure 1,

figure 3 is a cross-sectional view of C-C in figure 2,

figure 4 is a cross-sectional view of D-D in figure 2,

in the figure: the device comprises a lower die 1, an upper die 2, a floating seat spring 3, an outer guide post 4, an outer connecting plate 5, a screw 6, a screw plug 7, a floating seat 8, an outer guide sleeve 9, a buffer ring 10, a support post 11, an inner guide post 12, an inner connecting plate 13, a pin groove 14, a floating pin 15, a floating pin spring 16, an inclined part 17, a round tube 18, a punch 19, a driving rod 20, a prepressing seat 21, a pressure rod 22, a pressure seat spring 23, a lower shaft 24, a lower shaft joint 25, a lower shaft head 26, an upper shaft 27, an upper shaft joint 28, an inner guide sleeve 29, a spring seat 30, a shaft descending spring 31, an upper shaft head 32, a front cover strip 33, a side cover strip 34, a tooth projection 35, a groove 36, a notch 37, an arc groove 38, a crescent groove 39, a through hole 40, a support piece 41 and a cam groove 42.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived from the embodiments of the present invention by a person skilled in the art, are within the scope of the present invention.

As shown in fig. 1-4, the tight-teeth type retractable inner shaft mechanism for punching pipes described in this embodiment comprises an upper die 2, a punch 19 provided on the upper die 2, an arc-shaped groove 38 provided on the lower die 1 and the lower die 1, an outer guide post 4 fixed on the lower die 1, a floating seat 8 and an outer guide sleeve 9 which can move up and down sequentially sleeved on the outer guide post 4 from bottom to top, the outer guide sleeve 9 connected and fixed with the floating seat 8, an outer connecting plate 5 connected to the free end of the outer guide post 4, a floating seat spring 3 sleeved on the outer guide post 4 between the bottom of the floating seat 8 and the lower die 1, a crescent 39 which is close to and coaxial with the arc-shaped groove 38 and is provided on the floating seat 8, a lower shaft 25 which can move left and right along the axial direction of the crescent 39 is provided in the crescent 39, an upper shaft head 28 provided on the top of the lower shaft 25, two lower shafts 24 and a lower shaft head 26 connected to one end of the lower shaft 25 close to the arc-shaped groove 38 sequentially, one end of the upper shaft joint 28 close to the arc groove 38 is sequentially connected with two upper shafts 27 and an upper shaft head 32, the floating seat 8 is provided with an inner guide pillar 12 which sequentially penetrates through the upper shaft joint 28 and the lower shaft joint 25 and is fixed at the bottom of the crescent groove 39, the inner guide pillar 12 is sleeved with an inner guide sleeve 29 which is fixed at the top of the upper shaft joint 28 and can move up and down along the inner guide pillar 12, the free end of the inner guide pillar 12 is connected with an inner connecting plate 13, a shaft descending spring 31 which is sleeved on the inner guide pillar 12 is arranged between the inner guide sleeve 29 and the inner connecting plate 13, the lower shaft joint 25 is provided with a cam groove 42, the inner connecting plate 13, the upper shaft joint 28, the floating seat 8 and the lower die 1 are provided with a through hole 40 corresponding to the cam groove 42, the four through holes 40 and the cam groove 42 jointly form a rod channel, a driving rod 20 of which is sleeved with the upper end fixed on the upper die 2 is arranged in the rod channel, the driving rod 20 is provided with an inclined part 17 which can be matched with the cam groove 42 to drive the lower shaft joint 25 to move left and right, the top of the lower shaft 24 and the bottom of the upper shaft 27 are both provided with a tooth groove mechanism formed by a plurality of tooth protrusions 35 and a plurality of grooves 36 at intervals, the arc-shaped groove 38 is provided with a pin groove 14, the bottom of the pin groove 14 is sequentially connected with a floating pin spring 16 and a floating pin 15, the upper die 2 is fixed with a prepressing seat 21, a pressing rod 22 capable of moving up and down is sleeved in the prepressing seat 21, and a pressing seat spring 23 is arranged between the prepressing seat 21 and the top of the pressing rod 22.

The pin slot 14 consists of a pin hole and a screw plug 7 at the bottom of the pin hole, the top of the floating pin 15 is an inclined plane which is close to the side of the lower shaft joint 25 and is high, the upper part of the floating pin 15 supports the lower shaft 24 under the elastic force action of a floating pin spring 16, and when the workpiece round tube 18 is sleeved outside the upper shaft 27 and the lower shaft 24, the upper part of the floating pin 15 supports the workpiece round tube 18.

When the upper die 2 drives the driving rod 20 to move up and down, the inclined part 17 of the driving rod 20 cooperates with the wall of the cam groove 42 to push the lower shaft joint 25 to move left and right, so that the lower shaft 24 rigidly connected with the lower shaft joint 25 moves left and right in the arc-shaped groove 38 of the lower die 1.

A buffer ring 10 sleeved on the outer guide pillar 4 is arranged between the outer guide sleeve 9 and the outer connecting plate 5, so that collision impact between the outer guide sleeve 9 and the outer connecting plate 5 is relieved, and the service life is prolonged.

Four outer guide posts 4 are fixed on the lower die 1, the floating seat 8 is sleeved on the four outer guide posts 4 simultaneously, two free ends on the same sides of the free ends of the four outer guide posts 4 are connected to two outer connecting plates 5 respectively as a group, two pressure rods 22 capable of moving up and down are sleeved in the prepressing seat 21, the two outer connecting plates 5 are respectively provided with a notch 37 for the pressure rods 22 to pass through, front and rear sides of the floating seat 8 are respectively provided with a front cover strip 33 fixed on the lower die 1, left and right sides of the floating seat 8 are respectively provided with a side cover strip 34 fixed on the lower die 1, when the upper die 2 is lifted up and down, the pressure rods 22 are driven to lift up and down, the floating seat 8 is pushed or loosened, and simultaneously, the floating seat 8, under the pushing of the floating seat spring 3, the floating seat 8, the outer guide sleeve 9 and parts arranged on the floating seat 8 can float up and down along the outer guide posts 4.

A supporting column 11 for reinforcement is connected between the inner connecting plate 13 and the floating seat 8.

A spring seat 30 sleeved on the inner guide post 12 is arranged between the inner guide sleeve 29 and the shaft lowering spring 31, so that the spring force applied to the inner guide sleeve 29 is more uniform and stable.

A plurality of lower shafts 24 can be connected between the lower shaft joint 25 and the lower shaft head 26 according to the length of the pipe to be processed, a plurality of upper shafts 27 can be connected between the upper shaft joint 28 and the upper shaft head 32 according to the length of the pipe to be processed, and a plurality of semicircular supporting pieces 41 are uniformly arranged on the top end surface of each upper shaft 27.

The upper shaft 27 and the upper shaft joint 28, the upper shaft 27 and the upper shaft head 32, the lower shaft 24 and the lower shaft joint 25 and the lower shaft 24 and the lower shaft head 26 are fixed through screws 6 and cylindrical pins.

And (3) implementing an action process: the round pipe 18 penetrates through the upper shaft head 32 and the lower shaft head 26 from right to left, the inclined plane of the floating pin 15 is pushed by the left end face side of the round pipe 18, the floating pin spring 16 is further compressed, the lower surface of the round pipe 18 is supported by the upper surface of the floating pin 15, the lower surface of the inner surface of the round pipe 18 is attached to the lower surface of the lower shaft 24, the upper die 2 descends after the round pipe 18 is pushed to the right, the pressing rod 22 penetrates through the gap 37 to press the floating seat 8, the floating seat 8 descends to compress the floating seat spring 3, the pressing rod 22 pushes the pressing seat spring 23 on the upper portion to be compressed, and the bottom of the floating seat 8 stops when contacting with the lower die 1; at the moment, the upper die 2 continues to move downwards, the pressure rod 22 continues to push the upper pressure seat spring 23 to compress, the left inclined surface of the inclined part 17 of the driving rod 20 contacts the left inclined surface of the cam groove 42 of the lower shaft connector 25, the lower shaft connector 25 and the rigidly connected lower shaft 24 are pushed to move leftwards, the tooth projection 35 in the tooth groove mechanism on the upper part of the lower shaft 24 is changed from being matched with the groove 36 of the upper shaft 27 to being matched with the tooth projection 35 of the upper shaft 27, and then the upper shaft 27 moves upwards until the outer surface of the upper shaft 27 tightly supports the inner surface of the circular tube 18; at the moment, the upper die 2 continues to move downwards, the punch 19 arranged on the upper die 2 enters the gap between the two adjacent supporting pieces 41, and the circular tube 18 starts to be punched, so that a groove is cut in the circular tube 18; then the upper die 2 starts to move upwards, and the punch 19 is separated from the circular tube 18 along with the upper die 2; the upper die 2 continues to move upwards, the right inclined surface of the inclined part 17 of the driving rod 20 contacts the right inclined surface of the cam groove 42 of the lower shaft joint 25, the lower shaft joint 25 and the rigidly connected lower shaft 24 are pushed to move rightwards, the upper shaft joint 28 and the upper shaft 27 together with the inner guide sleeve 29 move downwards along the inner guide post 12 under the elastic force of the shaft lowering spring 31, the tooth projection 35 in the tooth socket mechanism at the bottom of the upper shaft 27 is changed from being matched with the tooth projection 35 of the lower shaft 24 to being matched with the groove 36 of the lower shaft 24, and the surface of the upper shaft 27 is in a loose state with the inner surface of the circular tube 18; the upper die 2 continues to move upwards, the lower part of the pressure rod 22 is separated from the upper part of the floating seat 8, the seat pressing spring 23 at the upper part of the pressure rod 22 is restored to an initial state, the floating seat 8 floats to the upper part of the buffer ring 10 and is stopped when being attached to the outer connecting plate 5 under the action of the elastic force of the floating seat spring 3, the floating seat 8 floats together with the lower shaft joint 25, the lower shaft 24 and the upper shaft 27 when upwards floating, the lower surface of the circular tube 18 is separated from the inner wall of the arc-shaped groove 38 of the lower die 1, the upper die 2 continues to move upwards until the upper dead center of the upper die 2 is stopped, then the finished circular tube 18 is manually pulled out rightwards, the floating pin 15 rises under the elastic force of the floating pin spring 16 to support the lower shaft 24, and a work cycle is completed.

The inner shaft movement action is synchronously and automatically completed in the working process of the die, so that one person for pulling out the inner shaft can be saved, the labor cost is saved, and the production efficiency is improved; the inner shaft is not easy to wear and has long service life, and the finished product has stable quality; the length of the inner shaft can be freely spliced in sections according to the length of the processed pipe, so that the processing difficulty and the processing cost of the inner shaft are greatly reduced, and the adaptability to the length of a product is high; the whole inner shaft mechanism can float up and down, and the pipe taking and placing are convenient.

The present invention is not limited to the above-mentioned preferred embodiments, and any other products in various forms can be obtained by anyone in the light of the present invention, but any changes in the shape or structure thereof, which have the same or similar technical solutions as those of the present application, fall within the protection scope of the present invention.

Claims

1. The utility model provides a die-cut with close tooth type axle mechanism that can contract of die-cut of tubular product, including last mould (2), punch (19) that last mould (2) was equipped with, arc wall (38) that lower mould (1) and lower mould (1) were equipped with, characterized in that, be fixed with outer guide pillar (4) on lower mould (1), outer guide pillar (4) from bottom to top in proper order the cover be equipped with float seat (8) and outer guide pin bushing (9) that all can reciprocate, outer guide pin bushing (9) are connected with float seat (8) and are fixed, outer guide pillar (4) free end is connected with outer connecting plate (5), be equipped with float seat spring (3) of cover setting on outer guide pillar (4) between float seat (8) bottom and lower mould (1), float seat (8) are equipped with crescent (39) that just abut against and coaxial with arc wall (38), be equipped with in crescent wall (39) and can follow crescent wall (39) axial lower coupling (25) that move about crescent wall (39), lower coupling (25) top is equipped with upper shaft coupling (28), the one end that lower shaft coupling (25) is connected with arc wall (24) and crescent shaft coupling (26) is equipped with two in order and (26) and pass through arc wall coupling (26) and connect (27) in proper order and connect (25), the last shaft coupling (28) and pass through the last guide pillar (25) in proper order (25), it is connected with (28) and connect (25) and pass through the last shaft coupling (28) and connect (25) and pass through the last guide pillar (25) in turn (25) and be connected with the last shaft coupling (26) that the last guide pillar (25) that the last shaft coupling (25) is equipped with the last shaft coupling (25) is connected with the last shaft coupling (25) and (26) that the last shaft coupling (25) is connected with the last shaft coupling (26) in order that the guide pillar (25) is connected with the last shaft coupling (25) is connected with in order that the last shaft coupling (25) is connected with the last shaft coupling (26) is connected with in that the guide pillar (25) is connected with in turn (26) is connected with the guide pillar (25) and the last shaft coupling (25) is connected with the guide pillar (25) is connected with in order that the last shaft coupling (25) in that the guide pillar (25) is connected with in order that the guide pillar (25) is connected with the last shaft coupling (25) is connected with the order that the upper shaft coupling (26) is connected with the last shaft coupling (25) is connected with the upper shaft coupling (26) in order 12 An inner guide sleeve (29) which is fixed on the top of an upper shaft joint (28) and can move up and down along the inner guide column (12) is sleeved on the inner guide column (12), the free end of the inner guide column (12) is connected with an inner connecting plate (13), a shaft lowering spring (31) which is sleeved on the inner guide column (12) is arranged between the inner guide sleeve (29) and the inner connecting plate (13), a cam groove (42) is arranged in a lower shaft joint (25), the inner connecting plate (13), an upper shaft joint (28), a floating seat (8) and a lower die (1) are respectively provided with a through hole (40) corresponding to the cam groove (42), four through holes (40) and the cam groove (42) jointly form a rod channel, a driving rod (20) with the upper end fixed on an upper die (2) is sleeved in the rod channel, a section of mechanism which can be matched with the cam groove (42) to drive the lower shaft joint (25) to move left and right is arranged on the driving rod (20), a prepressing groove (17) which is arranged at intervals on the top of the lower shaft (24) and the bottom of the upper shaft (27), a prepressing groove (38) is provided with a prepressing pin groove (14), a prepressing pin groove (14) which is connected with a floating pin seat (14) and a prepressing pin (21) which are sequentially connected with a prepressing pin (16), a pressure seat spring (23) is arranged between the prepressing seat (21) and the top of the pressure rod (22); the pin groove (14) consists of a pin hole and a screw plug (7) at the bottom of the pin hole, and the top of the floating pin (15) is an inclined plane which is close to the height of one side of the lower shaft joint (25); a buffer ring (10) sleeved on the outer guide post (4) is arranged between the outer guide sleeve (9) and the outer connecting plate (5).

2. The tight-teeth type expansible inner shaft mechanism for die cutting of pipes according to claim 1, characterized in that four outer guide posts (4) are fixed on the lower die (1), a floating seat (8) is sleeved on the four outer guide posts (4) simultaneously, two free ends on the same side of the free ends of the four outer guide posts (4) are connected to two outer connecting plates (5) respectively in a group, two pressing rods (22) capable of moving up and down are sleeved in the pre-pressing seat (21), the two outer connecting plates (5) are provided with notches (37) for the passage of the pressing rods (22), front cover strips (33) fixed on the lower die (1) are arranged on the front side and the rear side of the floating seat (8), and side cover strips (34) fixed on the lower die (1) are arranged on the left side and the right side of the floating seat (8).

3. The retractable internal shaft mechanism of the close-toothed type for die cutting a pipe according to claim 1, wherein a pillar (11) for reinforcement is connected between the inner connecting plate (13) and the floating seat (8).

4. The tight-teeth type retractable inner shaft mechanism for die cutting the tube according to claim 1, wherein a spring seat (30) sleeved on the inner guide post (12) is arranged between the inner guide sleeve (29) and the shaft lowering spring (31), so that the spring force applied to the inner guide sleeve (29) is more uniform and stable.

5. The inner shaft mechanism capable of being expanded in a close-teeth manner for die cutting the tube according to claim 1, wherein at least one lower shaft (24) is connected between the lower shaft joint (25) and the lower shaft head (26), at least one upper shaft (27) is connected between the upper shaft joint (28) and the upper shaft head (32), and a plurality of semicircular supporting sheets (41) are uniformly arranged on the top end surface of the upper shaft (27).

6. The retractable inner shaft mechanism with dense teeth for die cutting of tubes of claim 1, wherein the upper shaft (27) and the upper shaft joint (28), the upper shaft (27) and the upper shaft head (32), the lower shaft (24) and the lower shaft joint (25), and the lower shaft (24) and the lower shaft head (26) are fixed by screws (6) and cylindrical pins.