CN115488703B

CN115488703B - Knife sharpening device for spreading machine

Info

Publication number: CN115488703B
Application number: CN202211381776.3A
Authority: CN
Inventors: 钟淑玲
Original assignee: Sufeide China Automation Technology Co ltd
Current assignee: Sufeide China Automation Technology Co ltd
Priority date: 2022-11-04
Filing date: 2022-11-04
Publication date: 2023-05-16
Anticipated expiration: 2042-11-04
Also published as: CN115488703A

Abstract

The invention discloses a knife sharpening device for a spreading machine, which comprises a frame, wherein a moving seat is connected to the frame in a sliding way left and right, a first driving mechanism for driving the moving seat to move left and right is arranged on the frame, a knife holder for fixing a knife blade is arranged on the frame, the knife holder is rotationally arranged on the frame, a second driving mechanism for driving the knife holder to rotate is arranged on the frame, knife sharpening mechanisms are arranged on the left side and the right side of the moving seat relative to a knife blade, each knife sharpening mechanism comprises a sliding seat and a knife sharpening stone, the knife sharpening stones are obliquely arranged on the sliding seats, sliding grooves are formed in the moving seats, the sliding seats are connected in the sliding grooves in a sliding way, and a constant force mechanism which acts on the sliding seats after the knife sharpening stones collide the knife blade is arranged in the sliding grooves. This knife sharpening device for granny rag machine can polish the cutting edge both sides of blade better, improves the effect of polishing.

Description

Knife sharpening device for spreading machine

Technical Field

The invention relates to the field of knife sharpening devices, in particular to a knife sharpening device for a spreading machine.

Background

The automatic cloth spreading machine is suitable for: the automatic cloth spreading machine has the advantages that series of processing fabrics such as clothing, underwear, home textiles, furniture, non-wovens and the like are processed, a PLC touch screen is operated, tension-free cloth spreading operation is performed, operation is simplified, production efficiency is improved, quality is guaranteed, but a cutting blade on the automatic cloth spreading machine becomes blunt after working for a period of time, the cutting blade is polished by a manual knife stone for a long time, time and labor are wasted, grinding effect is uneven, and grinding efficiency is low.

The authorized bulletin number is: CN207606602U discloses an automatic knife sharpening device of a spreading machine, which comprises a base, base upside both ends are provided with the second backup pad perpendicularly, two the second backup pad downside all is provided with the bearing, two the level is provided with same pivot in the bearing, the pivot runs through the bearing, and is located the both ends of the inboard pivot of two bearings are provided with two second gears respectively, base upside one end is provided with the motor, the output shaft of motor and the one end fastening connection of pivot, two the second backup pad inboard all is provided with the sharpening unit, the sharpening unit is including setting up the recess inboard at the second backup pad, both sides all are provided with the bayonet socket about the recess, two horizontal roll is provided with the connecting axle on the bayonet socket, be provided with first gear on the connecting axle, first gear meshes with the second gear, connecting axle one end is provided with coupling mechanism, two on the coupling mechanism be provided with the emery wheel perpendicularly second backup pad upper end all horizontally is provided with first backup pad, two first backup pad upside one end is provided with the stopper, two on the first backup pad upside all is provided with two stopper, two on the side all are provided with two fixture blocks, two clamping blocks all are provided with two inboard bolt. The grinding wheel arranged on the connecting shaft is driven by the motor and the gear, so that the automation of sharpening is realized, manual sharpening by using the sharpening stone is avoided, and the working efficiency is accelerated. Although the two sides of the blade can be polished through the two grinding wheels, the knife sharpening device cannot polish the blade edge of the blade well, and the polishing effect is poor.

The Chinese patent with the authorized bulletin number of CN201807951U discloses an automatic knife sharpening device for a spreading machine, which comprises a knife sharpening mechanism and a travelling mechanism, wherein the travelling mechanism comprises a guide rail and a guide wheel fixed on a guide wheel connecting plate, the guide wheel is connected with the guide rail in a matched manner, two ends of the guide rail are provided with collision blocks, and the knife sharpening assembly is connected with the guide wheel connecting plate of the travelling mechanism through a connecting piece; the knife sharpening mechanism comprises a mounting plate and a grinding wheel assembly, wherein the grinding wheel assembly is arranged on one side of the mounting plate, a circular blade connected with an output shaft of a motor is arranged on the other side of the mounting plate, and the grinding wheel assembly can penetrate through a through hole in the mounting plate and is in contact with the circular blade at a certain inclination angle. The grinding wheel component and the blade of the automatic knife sharpening device are obliquely arranged, one side of the cutting edge of the blade can be polished, the other side of the cutting edge of the blade is not polished, the phenomenon of burrs is easy to occur on cloth when the cloth is cut by the cutting edge of the side of the blade, and the cutting is unqualified for cloth with strict quality requirements.

Therefore, for some cloth materials with high cutting requirements, a knife sharpening device capable of sharpening both edges of the blade is needed in the market, and the sharpening device has good sharpening effect.

Disclosure of Invention

In order to polish both sides of the cutting edge of the blade better, the polishing effect is improved, and the application provides a knife sharpening device for a spreading machine.

The application provides a knife sharpening device for granny rag machine adopts following technical scheme:

the utility model provides a knife sharpening device for granny rag machine, includes the frame, it is connected with the removal seat to slide about in the frame, be equipped with the drive in the frame and remove the first actuating mechanism that the seat left and right moved, be equipped with the blade holder that is used for fixed blade in the frame, the blade holder rotationally sets up in the frame, the frame is equipped with the pivoted second actuating mechanism of drive blade holder, it all is provided with sharpening mechanism for the left and right sides of blade to remove the seat, sharpening mechanism includes seat and whetstone that slides, whetstone slope sets up on the seat that slides, the seat that slides has seted up the groove that slides on the removal seat, the seat that slides is connected in the inslot that slides, the inslot that slides is equipped with when whetstone contradicts the blade and acts on the constant force mechanism on the seat that slides.

Through adopting above-mentioned technical scheme, will need to wait to grind the blade fixed earlier on the blade holder to make the blade rotatory come through second actuating mechanism, first actuating mechanism can drive and remove the seat and control and remove, make the whetstone that is located the blade left and right sides can polish the blade left and right sides alternately, at the in-process that whetstone and blade polished, slide the seat and remove and can take place relative movement between the seat, constant force mechanism will have the same force to slide on the seat, such structure makes can polish the both sides cutting edge of blade, and polish more evenly, the effect of polishing is better.

Optionally, the movable seat includes the movable table and slides two movable blocks of connection on the movable table, be equipped with the movable groove that supplies the movable block to slide on the movable table, the movable table slides and connects in the frame, be provided with the first bi-directional screw that contains two sections screw threads and revolve to opposite directions rotationally on the movable table, two movable blocks are passed respectively to first bi-directional screw, just every section screw thread section of first bi-directional screw is connected with one of them movable block screw thread respectively.

Through adopting above-mentioned technical scheme, to some blades are thinner, the time of disposable grinding is just less than the blade that the grinding volume is less, and to some blades are thicker, the blade that the grinding volume is more that needs is more, the time that needs the grinding is just longer, can control two movable blocks relative movement through rotating first bi-directional screw in this application, can adjust the interval between two movable blocks, thereby can adjust the initial distance between whetstone and the blade, thereby can control the time that the movable seat makes a round trip to grind, make can be applicable to the demand that more blades were polished, enlarge its application range.

Optionally, the constant force mechanism includes body, body of rod and piston, the fixed one end that sets up at the body of rod of piston, the piston sets up in the body of rod and forms sealed cooperation with the body of rod inner wall slidingly, the outer end of the body of rod is connected with the seat that slides, the body of rod is relative to the other end of the seat that slides and is connected with the groove inner wall that slides, be equipped with the through-hole with the body of tube intercommunication on the outer wall of movable block, be equipped with the end cap in the through-hole, the end cap is equipped with the through-hole with the body of tube intercommunication, end cap and movable block threaded connection, be equipped with the reset lever that order about to slide the seat and reset in the frame, leave the removal clearance between reset lever and the blade.

Through adopting above-mentioned technical scheme, the whetstone contradicts the blade and continues to remove the back, and the seat of sliding can with movable block relative movement, and the body of rod can retract in toward the body this moment, and the gas in the body of tube can outwards flow through the through-hole simultaneously, and during this period, the inside air of body of tube can produce a balanced resistance to the piston, and the resistance can be transmitted to the seat of sliding through the body of rod on, makes the seat of sliding can receive a constant force to the effort that makes the whetstone effect on the blade is balanced, makes to polish more evenly, improves the effect of polishing.

Optionally, the reset rod slides and connects in the frame, rotationally be provided with in the frame and contain two sections screw thread and revolve the opposite second bidirectional screw rod of direction, the second bidirectional screw rod passes two reset rods respectively, just every section screw thread section of second bidirectional screw rod respectively with one of them reset rod threaded connection.

Through adopting above-mentioned technical scheme, can control two reset levers relative movement through the rotation second bidirectional screw rod, can adjust the interval between two reset levers, can then carry out the adaptability to the reset lever according to the position of movable block after adjusting.

Optionally, a venting hole is formed in the outer wall, close to one end of the blade, of the pipe body, the venting hole is communicated with the inside of the pipe body, and when the piston is located at one side closest to the blade, the venting hole is located between the piston and the plug.

Through adopting above-mentioned technical scheme, because the setting of gas vent for the piston is at the beginning when moving in the body, and the resistance that gas in the body produced to the piston can be less, thereby the effort of originally acting on sliding seat is also less, makes the whetstone when bumping with the blade, and both are difficult for impaired.

Optionally, the air leakage hole includes a plurality of, and the aperture of air leakage hole from piston one side to end cap one side reduces gradually.

Through adopting above-mentioned technical scheme, the aperture of gas vent from piston one side to end cap one side reduces gradually for the in-process that the piston in the pipe was moving, the air resistance that receives can increase gradually, makes the effort that acts on the seat of sliding also can increase gradually, thereby can further protect whetstone and blade.

Optionally, the sliding seat is provided with a limiting rod, the frame is provided with two limiting blocks for controlling grinding feeding amount, and the projection surface of the limiting rod in the sliding direction of the sliding seat is intersected with the adjacent limiting blocks.

Through adopting above-mentioned technical scheme, setting up of gag lever post and stopper can carry out spacingly to the seat of sliding for the whetstone is polished and is fallen behind the fixed grinding volume, and the seat of sliding just can not be moved towards the blade direction any more, thereby can control the grinding volume better.

Optionally, the stopper slides and connects in the frame, rotationally be provided with in the frame and contain two sections screw threads and revolve the opposite third two-way screw rod of direction, the third two-way screw rod passes two stoppers respectively, just every section screw thread section of third two-way screw rod respectively with one of them stopper threaded connection.

Through adopting above-mentioned technical scheme, can adjust the position of stopper through rotating third two-way screw rod to can adapt to the needs of different grinding amounts.

Optionally, the seat of sliding includes the slider and rotates the rotating block of connecting on the slider, the whetstone is installed on the rotating block, the bottom of rotating block is equipped with a plurality of rotation teeth, the threaded rod with rotation tooth meshing is rotationally equipped with in the slider.

Through adopting above-mentioned technical scheme, can drive the pivoted piece and rotate after through rotating the threaded rod to can adjust the inclination of whetstone, with the needs of polishing of adaptation different blades.

Optionally, be equipped with the support frame on the mobile station, be equipped with the gangbar rotationally on the support frame, the cross section of gangbar is the polygon, the gangbar passes the threaded rod of left and right sides respectively, the threaded rod is equipped with the polygon hole that mutually supports with the gangbar, the sliding block is equipped with the pivoted groove that supplies the gangbar to rotate, and the threaded rod screw thread of left and right sides revolves to opposite.

Through adopting above-mentioned technical scheme, can drive two threaded rods through rotating the gangbar and rotate together to can drive two whetstones synchronous rotation, such structure makes the angle that two whetstones inclined keep unanimous as far as possible at the in-process of adjustment on the one hand, makes operating personnel operate more conveniently simultaneously.

In summary, the present application includes at least one of the following beneficial technical effects:

the utility model provides a knife sharpening device for granny rag machine can rotate the blade to use the constant force to polish the both sides cutting edge of blade through the sharpening mechanism of left and right sides, make the cutting edge of blade left and right sides can be polished more even, improve the effect of polishing.

Drawings

Fig. 1 is a perspective view of a first embodiment of the present application.

Fig. 2 is a schematic structural diagram of a first embodiment of the present application.

Fig. 3 is an enlarged view at a in fig. 2.

Fig. 4 is an enlarged view at B in fig. 2.

Reference numerals illustrate: 1. a frame; 2. a movable seat; 21. a mobile station; 22. a moving block; 23. a moving groove; 24. a first bi-directional screw; 3. a first driving mechanism; 31. a reciprocating screw; 32. a slide block; 33. a driving motor; 4. a tool apron; 5. a second driving mechanism; 6. a knife sharpening mechanism; 61. a sliding seat; 611. a sliding block; 612. a rotating block; 613. rotating the teeth; 614. a threaded rod; 62. a knife stone; 63. a slip groove; 7. a constant force mechanism; 71. a tube body; 72. a rod body; 73. a piston; 74. a through hole; 75. a plug; 76. a through hole; 77. a reset lever; 78. moving the gap; 8. polygonal holes; 9. a vent hole; 10. a limit rod; 11. a limiting block; 12. a support frame; 13. a linkage rod; 14. a blade; 15. a corrugated cover.

Description of the embodiments

The present application is described in further detail below in conjunction with figures 1-4.

An embodiment I discloses a knife sharpening device for a spreading machine. Referring to fig. 1 and 2, the knife grinder for the spreading machine comprises a frame 1, a moving seat 2 is slidingly connected left and right on the frame 1, a first driving mechanism 3 for driving the moving seat 2 to move left and right is arranged on the frame 1, the first driving mechanism 3 adopts a structure of a reciprocating screw 31, the first driving mechanism 3 comprises the reciprocating screw 31 and a driving motor 33 for driving the reciprocating screw 31 to rotate, a sliding block 32 on the reciprocating screw 31 is connected with the moving seat 2, when the motor drives the reciprocating screw 31 to rotate, the sliding block 32 on the reciprocating screw 31 can drive the moving seat 2 to move left and right back and forth, a knife seat 4 for fixing a blade 14 is further arranged on the frame 1, the blade 14 is rotationally arranged on the frame 1, the blade 14 is fastened on the knife seat 4 through bolts, the frame 1 is provided with a second driving mechanism 5 for driving the knife seat 4 to rotate, the second driving mechanism 5 is a motor, the moving seat 2 is provided with a knife grinder 6 relative to the left side and the right side of the blade 14, the knife grinder 6 comprises a knife grinder 61 and a knife 62, the knife 62 is obliquely arranged on the sliding seat 61, a sliding groove 63 is formed in the moving seat 2, and the sliding seat 61 is connected with the knife grinder 62, and the sliding seat 63 is in the sliding seat 61 is in the sliding seat 7 and is in the sliding seat 6 and is in the sliding seat 7.

Referring to fig. 1 and 2, the movable base 2 includes a movable table 21 and two movable blocks 22 slidably connected to the movable table 21, a movable slot 23 for sliding the movable blocks 22 is provided on the movable table 21, the movable table 21 is slidably connected to the frame 1, a first bidirectional screw 24 having two sections of threads with opposite directions is rotatably provided on the movable table 21, the first bidirectional screw 24 passes through the two movable blocks 22, and each section of thread of the first bidirectional screw 24 is in threaded connection with one of the movable blocks 22. When the first bidirectional screw 24 is rotated, the two moving blocks 22 can be driven to be far away from each other or close to each other, and the distance between the two moving blocks 22 can be adjusted, so that the initial distance between the whetstone 62 and the blade 14 can be adjusted, and the time for feeding the whetstone 62 for grinding once can be controlled.

Referring to fig. 2 and 3, the constant force mechanism 7 includes a tube 71, a rod 72 and a piston 73, the piston 73 is fixedly disposed at one end of the rod 72, the piston 73 is slidably disposed in the tube 71 and forms a sealing fit with the inner wall of the tube 71, the outer end of the rod 72 is connected with the sliding seat 61, the other end of the tube 71 opposite to the sliding seat 61 is in sealing connection with the inner wall of the sliding groove 63, a through hole 74 communicated with the tube 71 is disposed on the outer wall of the moving block 22, a plug 75 is disposed in the through hole 74, a through hole 76 communicated with the tube 71 is disposed in the plug 75, and the plug 75 is in threaded connection with the moving block 22. When the first driving mechanism 3 drives the moving seat 2 to move, the knife stone 62 at one side will collide with the blade 14, so that the sliding seat 61 and the moving block 22 will move relatively, the sliding seat 61 will push the rod 72 to move, the piston 73 will squeeze the air in the tube 71, the air will flow out from the through hole 76, during this period, the air in the tube 71 will generate a balanced resistance to the piston 73, the resistance will be transmitted to the sliding seat 61 through the rod 72, so that the sliding seat 61 will receive a constant force.

Referring to fig. 1, a reset rod 77 for driving the sliding seat 61 to reset is provided on the frame 1, a moving gap 78 is left between the reset rod 77 and the blade 14, elastic rubber pads (not shown in the drawing) are provided on opposite side walls of the two reset rods 77, the reset rod 77 is slidingly connected to the frame 1, a second bidirectional screw (not shown in the drawing, refer to the first bidirectional screw 24) with two sections of threads having opposite rotation directions is rotatably provided on the frame 1, the second bidirectional screw passes through the two reset rods 77 respectively, and each section of thread of the second bidirectional screw is in threaded connection with one of the reset rods 77 respectively. When the first driving mechanism 3 drives the moving seat 2 to move to the right, the left side of the knife stone 62 will collide with the blade 14, so that the sliding seat 61 on the knife stone 62 will move relatively to the moving block 22 on the side, and the right side of the knife stone 62 will move along with the moving block 22 in the moving gap 78; when the first driving mechanism 3 drives the moving seat 2 to move reversely, the right sliding seat 61 just touches the elastic rubber pad on the corresponding reset rod 77, when the right whetstone 62 touches the blade 14 in the moving process, the left sliding seat 61 just touches the elastic rubber pad on the left reset rod 77, the moving seat 2 moves to move left, the right sliding seat 61 moves relatively to the moving block 22 on the left, and at the same time, the left reset rod 77 limits the left sliding seat 61 to move, so that the left sliding groove 63 also moves relatively to the moving block 22 on the left, and the left sliding seat 61 can reset, so that the cycle operates. The reset lever 77 can be adjusted in position by adjusting the second bi-directional screw according to the position of the moving block 22.

Referring to fig. 1, the outer wall of the pipe 71 near one end of the blade 14 is provided with air release holes 9, the air release holes 9 are mutually communicated with the inside of the pipe 71, when the piston 73 is positioned at the side closest to the blade 14, the air release holes 9 are positioned between the piston 73 and the plug 75, the number of the air release holes 9 is 3, and the aperture of the air release holes 9 is gradually reduced from the side of the piston 73 to the side of the plug 75. The arrangement of the air leakage hole 9 makes the resistance of the air in the pipe body 71 to the piston 73 smaller when the piston 73 moves in the pipe body 71, so that the knife stone 62 is not easy to damage when colliding with the blade 14, and the air leakage hole 9 is gradually reduced, so that the air resistance of the piston 73 in the pipe can be gradually increased in the moving process, the acting force acting on the sliding seat 61 can be gradually increased, and the knife stone 62 and the blade 14 can be further protected.

Referring to fig. 1, a sliding seat 61 is provided with a limiting rod 10, a frame 1 is provided with two limiting blocks 11 for controlling grinding feeding amount, and a projection surface of the limiting rod 10 relative to the sliding direction of the sliding seat 61 is intersected with the adjacent limiting blocks 11. In the process of moving forward, the knife stone 62 grinds the blade 14, and after the limiting rod 10 contacts with the limiting block 11, the sliding seat 61 can be limited to move forward continuously, so that the grinding amount can be controlled better. The limiting blocks 11 are slidably connected to the frame 1, a third bidirectional screw rod (not shown in the figure, and reference may be made to the first bidirectional screw rod 24) with two sections of threads having opposite screwing directions is rotatably provided on the frame 1, the third bidirectional screw rod passes through the two limiting blocks 11 respectively, and each section of thread section of the third bidirectional screw rod is in threaded connection with one of the limiting blocks 11 respectively. The position of the limiting block 11 can be adjusted by rotating the third bidirectional screw, so that the grinding machine can adapt to the requirements of different grinding amounts.

Referring to fig. 2 and 4, the sliding seat 61 includes a sliding block 611 and a rotating block 612 rotatably connected to the sliding block 611, the whetstone 62 is installed in an installation groove of the rotating block 612 and fastened by a bolt, a plurality of rotating teeth 613 are provided at the bottom of the rotating block 612, a threaded rod 614 engaged with the rotating teeth 613 is rotatably provided in the sliding block 611 by a bearing, a supporting frame 12 is provided on the moving table 21, a linkage rod 13 is rotatably provided on the supporting frame 12, the cross section of the linkage rod 13 is quadrangular, the linkage rod 13 passes through the threaded rods 614 on the left and right sides respectively, the threaded rod 614 is provided with polygonal holes 8 mutually matched with the linkage rod 13, the sliding block 611 is provided with a rotating groove for the rotation of the linkage rod 13, the linkage rod 13 passes out of the rotating groove and extends out of the sliding block 611, and the threads of the threaded rods 614 on the left and right sides are reversely rotated. The two threaded rods 614 can be driven to rotate together by rotating the linkage rod 13, so that the two whetstones 62 can be driven to synchronously rotate, and the angle of the whetstones 62 can be adjusted.

The corrugated cover 15 is provided at the place of the moving groove 23 and the sliding groove 63, and the corrugated cover 15 is provided so that the ground scrap iron is not easy to enter the groove.

The implementation principle of the knife sharpening device for the spreading machine is as follows: when the blade 14 needs to be polished, the blade 14 to be polished can be firstly fixed on the blade holder 4, the blade 14 is rotated by the second driving mechanism 5, the first driving mechanism 3 can drive the movable seat 2 to move left and right, when the movable seat 2 moves right, the left whetstone 62 can abut against the blade 14 to polish the left edge of the blade 14, meanwhile, the sliding seat 61 on the whetstone 62 can move relatively with the left movable block 22 (the sliding seat 61 and the movable block 22 move relatively, the constant force mechanism 7 can generate a constant force on the sliding seat 61), and the right whetstone 62 can move along with the right movable block 22 in the right movable gap 78.

When the first driving mechanism 3 drives the movable seat 2 to move reversely, the right sliding seat 61 just touches the elastic rubber pad on the corresponding reset rod 77, when the movable seat 2 moves leftwards integrally, the right whetstone 62 touches the blade 14 to polish the right edge of the blade 14, at the moment, the left sliding seat 61 just touches the elastic rubber pad of the left reset rod 77, the right sliding seat 61 and the movable block 22 on the right side move relatively in the process of moving the movable seat 2 continuously leftwards, at the same time, the left reset rod 77 can limit the left sliding seat 61 to move, so that the left sliding seat 61 and the corresponding movable block 22 move relatively, the left sliding seat 61 can reset, when the movable seat 2 moves rightwards integrally, the left whetstone 62 polishes the blade 14 again, the right sliding seat 61 can be reset by the right sliding seat 77, the cycle is operated, the operating time can be controlled according to the grinding quantity, and finally, when the blade 62 and the blade 14 do not contact with the whetstone 14, namely polishing is completed.

The main difference between the second embodiment and the first embodiment is that: the pipe 71 is not provided with the vent hole 9.

The foregoing are all preferred embodiments of the present application, and are not intended to limit the scope of the present application in any way, therefore: all equivalent changes in structure, shape and principle of this application should be covered in the protection scope of this application.

Claims

1. The utility model provides a knife sharpening device for granny rag machine, includes frame (1), its characterized in that: the utility model discloses a movable table, which is characterized in that a movable seat (2) is connected with the rack (1) in a sliding way left and right, a first driving mechanism (3) for driving the movable seat (2) to move left and right is arranged on the rack (1), a tool apron (4) for fixing a blade (14) is arranged on the rack (1), the tool apron (4) is rotationally arranged on the rack (1), a second driving mechanism (5) for driving the tool apron (4) to rotate is arranged on the rack (1), a sharpening mechanism (6) is arranged on the left side and the right side of the movable seat (2) relative to the blade (14), the sharpening mechanism (6) comprises a sliding seat (61) and a sharpening stone (62), the sharpening stone (62) is obliquely arranged on the sliding seat (61), a sliding groove (63) is formed in the movable seat (2), the sliding seat (61) is connected in the sliding groove (63), a force mechanism (7) for acting on the sliding seat (61) after the blade (14) is abutted, the movable seat (2) comprises a sliding seat (61) and a sliding block (21) and a sliding block (22) connected with the movable table (21), the movable table (21) is slidingly connected to the frame (1), a first bidirectional screw (24) with two sections of threads rotating oppositely is rotationally arranged on the movable table (21), the first bidirectional screw (24) respectively penetrates through two movable blocks (22), each section of thread section of the first bidirectional screw (24) is respectively in threaded connection with one movable block (22), the sliding seat (61) comprises sliding blocks (611) and rotating blocks (612) rotationally connected to the sliding blocks (611), the whetstone (62) is arranged on the rotating blocks (612), a plurality of rotating teeth (613) are arranged at the bottom of the rotating blocks (612), threaded rods (614) meshed with the rotating teeth (613) are rotationally arranged in the sliding blocks (611), a supporting frame (12) is arranged on the movable table (21), the cross section of each movable rod (13) is polygonal, the movable rod (13) respectively penetrates through the left side and right side (614) and is provided with a threaded rod (614) which is in threaded connection with the threaded rod (614) of the opposite directions, and the threaded rods (614) are provided with a threaded rod (614) which is in a threaded groove (13) which is matched with the threaded rod (13) on the left side and the right side (614), the constant force mechanism (7) comprises a tube body (71), a rod body (72) and a piston (73), wherein the piston (73) is fixedly arranged at one end of the rod body (72), the piston (73) is slidingly arranged in the tube body (71) and forms sealing fit with the inner wall of the tube body (71), the outer end of the rod body (72) is connected with the sliding seat (61), the tube body (71) is connected with the inner wall of the sliding groove (63) relative to the other end of the sliding seat (61), a through hole (74) communicated with the tube body (71) is formed in the outer wall of the moving block (22), a through hole (75) communicated with the tube body (71) is formed in the through hole (74), the plug (75) is in threaded connection with the moving block (22), a reset rod (77) driving the sliding seat (61) to reset is arranged on the frame (1), a moving gap (78) is reserved between the reset rod (77) and the blade (14), the reset rod (77) is slidingly connected with the frame (1), two opposite screws (77) are arranged on the frame (1) in a threaded mode, two opposite screw rods (77) are threaded to each other, and each section of thread section of the second bidirectional screw rod is respectively in threaded connection with one reset rod (77).

2. The knife sharpening device for a spreading machine according to claim 1, wherein: the outer wall of the pipe body (71) close to one end of the blade (14) is provided with a gas leakage hole (9), when the piston (73) is positioned at one side closest to the blade (14), the gas leakage hole (9) is communicated with the inside of the pipe body (71), and the gas leakage hole (9) is positioned between the piston (73) and the plug (75).

3. The knife sharpening device for a spreading machine according to claim 2, wherein: the air leakage holes (9) comprise a plurality of air leakage holes, and the aperture of the air leakage holes (9) gradually decreases from one side of the piston (73) to one side of the plug (75).

4. A knife grinder for a spreading machine according to claim 3, wherein: the sliding seat (61) is provided with a limiting rod (10), the frame (1) is provided with two limiting blocks (11) for controlling grinding feeding amount, and the projection surface of the limiting rod (10) in the sliding direction relative to the sliding seat (61) is intersected with the adjacent limiting blocks (11).

5. The knife sharpening device for a spreading machine according to claim 4, wherein: the limiting blocks (11) are connected onto the frame (1) in a sliding mode, a third bidirectional screw rod with two sections of threads in opposite screwing directions is rotationally arranged on the frame (1), the third bidirectional screw rod penetrates through the two limiting blocks (11) respectively, and each section of thread section of the third bidirectional screw rod is connected with one of the limiting blocks (11) in a threaded mode respectively.