Corrugated pipe fixed-length cutting equipment

Abstract

The invention discloses corrugated pipe fixed-length cutting equipment which comprises a rack, and a conveying device for driving a corrugated pipe to be conveyed in the length direction of the corrugated pipe is arranged on the rack; the sensing unit is arranged on the rack and used for sensing the wave crest part or the wave trough part of the corrugated pipe; the clamping device is used for positioning and clamping the corrugated pipe; and the cutting device is matched with the clamping device and can cut along the wave crest part of the corrugated pipe. In the forward conveying process of the corrugated pipe, the sensing unit can sense and record the number of the wave crest parts or the wave trough parts passing through, when the sensing unit senses a certain wave crest part or wave trough part, the corrugated pipe reaches the preset cutting length, and at the moment, the corresponding wave crest part of the corrugated pipe is just aligned with the cutting device; the clamping device clamps and positions the corrugated pipe, and then the cutting device cuts off the corrugated pipe, so that the notch position of the corrugated pipe can be ensured to be at the wave crest part, the cutting precision is favorably improved, and the possibility of cutting the surface of the electric wire is reduced.

Description

Technical Field

[0001] The present invention relates to a corrugated pipe fixed-length cutting device. Background Art

[0002] In the related art, corrugated pipes are often used as wire conduits to protect wires. In the subsequent processes of manufacturing corrugated pipes, it is necessary to cut the corrugated pipes according to a set length. Sharp cutting edges will be formed at the cut positions of the corrugated pipes. When the cut position of the corrugated pipe is at the trough part of the corrugated pipe, the wire is led out from the end of the corrugated pipe and is likely to rub against the cutting edge at the trough part, resulting in easy scratching of the wire skin. Therefore, if the cut position of the corrugated pipe is at the peak part of the corrugated pipe, the above situation can be improved.

[0003] However, traditional cutting knives or circumferential cutting methods cannot ensure that the cutting position is at the peak part of the corrugated pipe. Summary of the Invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art. For this purpose, the object of the present invention is to provide a corrugated pipe fixed-length cutting device that can ensure that the cutting position of the corrugated pipe is at the peak part, thereby facilitating the improvement of cutting accuracy and reducing the possibility of scratching the wire skin.

[0005] A corrugated pipe fixed-length cutting device according to an embodiment of the present invention includes: a frame, on which a transmission device is provided to drive the corrugated pipe to be conveyed along its length direction; an induction unit, provided on the frame, for sensing the peak part or trough part of the corrugated pipe; a clamping device, for positioning and clamping the corrugated pipe; and a cutting device, cooperating with the clamping device, capable of cutting along the peak part of the corrugated pipe.

[0006] A corrugated pipe fixed-length cutting device according to an embodiment of the present invention has at least the following beneficial effects:

[0007] The above-structured corrugated pipe fixed-length cutting device uses the transmission device to convey the corrugated pipe forward along its length direction. During the forward conveyance of the corrugated pipe, the induction unit can sense and record the number of peak parts or trough parts passing by. When the induction unit senses a certain peak part or trough part, the corrugated pipe reaches the preset cutting length. At this time, the corresponding peak part of the corrugated pipe is exactly aligned with the cutting device. The clamping device clamps and positions the corrugated pipe, and then the cutting device cuts the corrugated pipe, so as to ensure that the cut position of the corrugated pipe is at the peak part, which is beneficial to improving the cutting accuracy and reducing the possibility of scratching the wire skin.

[0008] In some embodiments of the present invention, a plurality of guiding sleeves are provided on the frame at intervals along the conveying direction of the corrugated pipe, and the inner diameter size of the guiding sleeves is adapted to the outer diameter size of the corrugated pipe.

[0009] In some embodiments of the present invention, the transmission device includes a first rotary conveyor belt and a second rotary conveyor belt located between two of the guiding sleeves. The second rotary conveyor belt and the first rotary conveyor belt are arranged at intervals in the vertical direction to define a clamping gap for clamping the corrugated pipe. The rotation directions of the second rotary conveyor belt and the first rotary conveyor belt are opposite to drive the corrugated pipe to advance along the axial direction of the guiding sleeve in a preset direction.

[0010] In some embodiments of the present invention, a through hole groove communicating with the inner cavity is formed in the pipe wall of one of the guiding sleeves. The sensing unit includes a laser sensor or a photoelectric sensor with its emitting end facing the through hole groove.

[0011] In some embodiments of the present invention, the clamping device includes a first clamping block, a second clamping block and a first driver. The first clamping block is provided with at least one first positioning groove corresponding to the peak portion of the corrugated pipe. The second clamping block is provided with a second positioning groove that matches the first positioning groove one by one. The first driver drives the first clamping block and the second clamping block to approach each other so that the first positioning groove and the corresponding second positioning groove jointly clamp and position a peak portion of the corrugated pipe.

[0012] In some embodiments of the present invention, the widths of the first positioning groove and the second positioning groove are both consistent with the width dimension of the peak portion of the corrugated pipe. The first clamping block is provided with a first slit groove with a side opening penetrating through the middle position of the width of one of the first positioning grooves. The second clamping block is provided with a second slit groove with a side opening penetrating through the middle position of the width of the corresponding second positioning groove. The cutting device includes a cutting blade and a second driver for driving the cutting blade to enter or leave the first slit groove and the second slit groove.

[0013] In some embodiments of the present invention, the first clamping block has a first semi-circular cavity facing the second clamping block. Four first semi-circular convex strips are arranged at intervals on the inner peripheral wall of the first semi-circular cavity. Adjacent two of the first semi-circular convex strips define a first positioning groove. The second clamping block has a second semi-circular cavity opposite to the first semi-circular cavity. Four second semi-circular convex strips are arranged at intervals on the inner peripheral wall of the second semi-circular cavity. Adjacent two of the second semi-circular convex strips define a second positioning groove. The first slit groove penetrates through the first positioning groove located in the middle. The second slit groove penetrates through the second positioning groove located in the middle.

[0014] In some embodiments of the present invention, the second driver is a motor, and an installation beam orthogonal to the output shaft of the motor is connected to the output shaft of the motor. One cutting blade is arranged at each end of the installation beam. The cutting blade has an arc-shaped cutting edge, and the two cutting blades are centrosymmetric about the center of the output shaft of the motor.

[0015] In some embodiments of the present invention, anti-adhesive coatings are coated on both side surfaces of the cutting blade.

[0016] In some embodiments of the present invention, the first clamping block and the second clamping block are both slidably arranged on the rack for lifting. The first driver includes two lifting cylinders respectively driving the first clamping block and the second clamping block to move up and down. At least one of the lifting cylinders is provided with a stroke detector, and the stroke detector, the lifting cylinder, and the transmission device are all electrically connected to the control module.

[0017] Additional aspects and advantages of the present invention will be given in part in the following description, become apparent in part from the following description, or be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The above and / or additional aspects and advantages of the present invention will become apparent and be readily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0019] Figure 1 is a schematic structural diagram of an embodiment of the corrugated pipe fixed-length cutting device of the present invention;

[0020] Figure 2 is Figure 1 a schematic structural diagram of the clamping device and the cutting device of the embodiment;

[0021] Figure 3 is a schematic structural diagram of the clamping device of the present invention;

[0022] Figure 4 is a schematic diagram of the first clamping block and the second clamping block.

[0023] Reference Signs:

[0024] corrugated pipe 10; peak part 11; trough part 12; rack 100; transmission device 200; first rotary conveyor belt 210; second rotary conveyor belt 220; induction unit 300; clamping device 400; first clamping block 410; first positioning groove 411; first knife slot 412; first semi-circular convex strip 413; second clamping block 420; second positioning groove 421; second knife slot 422; second semi-circular convex strip 423; first driver 430; cutting device 500; cutting blade 510; second driver 520; installation beam 530; guide sleeve 600; through hole slot 610. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0025] Embodiments of the present invention will be described in detail below. Examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the accompanying drawings are exemplary and are only used to explain the present invention and should not be construed as a limitation of the present invention.

[0026] In the description of the present invention, it should be understood that with regard to the orientation description, for example, terms such as "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0027] In the description of the present invention, the meaning of "several" is one or more, the meaning of "multiple" is more than two, and understandings such as "greater than", "less than", "exceeding", etc. do not include the present number, and understandings such as "above", "below", "within", etc. include the present number. If there is a description of "first" and "second", it is only for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features or implicitly indicating the sequence relationship of the indicated technical features.

[0028] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0029] See Figure 1 and Figure 2 , a bellows fixed-length cutting device of the present invention includes: a frame 100, a transmission device 200 provided on the frame 100 for driving the bellows 10 to be conveyed along its length direction; a sensing unit 300 provided on the frame 100 for sensing the peak portion 11 or the trough portion 12 of the bellows 10; a clamping device 400 for positioning and clamping the bellows 10; and a cutting device 500 cooperating with the clamping device 400 and capable of cutting along the peak portion 11 of the bellows 10.

[0030] The fixed-length cutting device for the corrugated pipe 10 with the above structure uses the transmission device 200 to convey the corrugated pipe 10 forward along the length direction of the corrugated pipe 10. During the forward conveyance of the corrugated pipe 10, the sensing unit 300 can sense and record the number of the passing peak portions 11 or valley portions 12. When the sensing unit 300 senses a certain peak portion 11 or valley portion 12, the corrugated pipe 10 reaches the preset cutting length. At this time, the corresponding peak portion 11 of the corrugated pipe 10 is exactly aligned with the cutting device 500. The clamping device 400 clamps and positions the corrugated pipe 10, and then the cutting device 500 cuts off the corrugated pipe 10, so as to ensure that the cutting position of the corrugated pipe 10 is at the peak portion 11, which is beneficial to improving the cutting accuracy and reducing the possibility of scratching the wire skin.

[0031] In this embodiment, when the sensing unit 300 detects a peak portion 11 of the corrugated pipe 10, at this time, another peak portion 11 of the corrugated pipe 10 is exactly aligned with the cutting device 500. As the transmission device 200 drives the corrugated pipe 10 to move forward, the sensing unit 300 detects the number of the passing peak portions 11, so as to calculate the length dimension of the corrugated pipe 10 cut at this time. When the preset value is reached, the clamping device 400 clamps and positions the corrugated pipe 10, and then the cutting device 500 cuts off the corrugated pipe 10.

[0032] Of course, in other embodiments, it can be set that when the sensing unit 300 detects a valley portion 12 of the corrugated pipe 10, at this time, a peak portion 11 of the corrugated pipe 10 is exactly aligned with the cutting device 500. As the transmission device 200 drives the corrugated pipe 10 to move forward, the sensing unit 300 detects the number of the passing valley portions 12, so as to calculate the length dimension of the corrugated pipe 10 cut at this time. In addition, the fixed-length cutting device for the corrugated pipe 10 with the above structure can also set the cutting position at the valley portion 12, and the user can set it according to actual needs.

[0033] See Figure 1 and Figure 2 In some embodiments of the present invention, a plurality of guiding sleeves 600 are arranged at intervals along the conveying direction of the corrugated pipe 10 on the frame 100, and the inner diameter dimension of the guiding sleeve 600 is adapted to the outer diameter dimension of the corrugated pipe 10. It can be understood that the arrangement of the guiding sleeve 600 can ensure that the corrugated pipe 10 is conveyed in a straight line, avoiding the corrugated pipe 10 from being bent or twisted, which affects the measurement accuracy and accuracy of the sensing unit 300, so as to ensure the length dimension of the corrugated pipe 10 to be cut and the cutting position at the peak portion 11.

[0034] See Figure 1, in some embodiments of the present invention, the transmission device 200 includes a first rotary conveyor belt 210 and a second rotary conveyor belt 220 located between two of the guide sleeves 600. The second rotary conveyor belt 220 and the first rotary conveyor belt 210 are arranged at intervals in the vertical direction to define a clamping gap for clamping the corrugated pipe 10. The rotation directions of the second rotary conveyor belt 220 and the first rotary conveyor belt 210 are opposite to drive the corrugated pipe 10 to advance along the axial direction of the guide sleeve 600 in a preset direction. It can be understood that the corrugated pipe 10 is located in the clamping gap, so that the outer peripheral wall of the corrugated pipe 10 contacts the first rotary conveyor belt 210 and the second rotary conveyor belt 220. The first rotary conveyor belt 210 and the second rotary conveyor belt 220 rotate towards each other and use friction to drive the corrugated pipe 10 to move forward. Specifically, the first rotary conveyor belt 210 and the second rotary conveyor belt 220 have the same structure, both including a plurality of pulleys and synchronous belts connected to the pulleys, and then the pulleys are driven to rotate by a motor.

[0035] See Figure 2 , in some embodiments of the present invention, a through-hole groove 610 communicating with its inner cavity is formed in the wall of one of the guide sleeves 600. The sensing unit 300 includes a laser sensor or a photoelectric sensor whose emitting end is disposed opposite to the through-hole groove 610. It can be understood that the parts of the corrugated pipe 10 located at both ends of the through-hole groove 610 are constrained by the guide sleeve 600, which is beneficial to ensuring that the corrugated pipe 10 moves intelligently along the central axis direction of the guide sleeve 600. A part of the corrugated pipe 10 is exposed from the through-hole groove 610, which is beneficial to improving the measurement accuracy. Taking the sensing unit 300 including a laser sensor as an example, the laser sensor emits laser pulses. The laser is scattered in all directions after being reflected by the outer peripheral wall of the corrugated pipe 10. Part of the scattered light returns to the receiving end of the laser sensor, and the optical signal becomes an electrical signal. Through filtering, amplification, and rectification by the corresponding circuit, an output signal is obtained, so as to calculate that the detected position is the peak part 11 or the trough part 12.

[0036] See Figure 3 and Figure 4, in some embodiments of the present invention, the clamping device 400 includes a first clamping block 410, a second clamping block 420 and a first driver 430. The first clamping block 410 is provided with at least one first positioning groove 411 corresponding to the peak portion 11 of the bellows 10. The second clamping block 420 is provided with a second positioning groove 421 that matches the first positioning groove 411 one by one. The first driver 430 drives the first clamping block 410 and the second clamping block 420 to approach each other so that the first positioning groove 411 and the corresponding second positioning groove 421 jointly clamp and position a peak portion 11 of the bellows 10. It can be understood that when the first driver 430 drives the first clamping block 410 and the second clamping block 420 to approach each other, the first positioning groove 411 and the corresponding second positioning groove 421 jointly clamp and position a peak portion 11 of the bellows 10, thereby accurately positioning and fixing the position of the bellows 10.

[0037] See Figure 3 and Figure 4 , in some embodiments of the present invention, the groove widths of the first positioning groove 411 and the second positioning groove 421 are both consistent with the width dimension of the peak portion 11 of the bellows 10. The first clamping block 410 is provided with a first slit groove 412 with a side opening along the middle position of the groove width of one of the first positioning grooves 411. The second clamping block 420 is provided with a second slit groove 422 with a side opening along the middle position of the groove width of the corresponding second positioning groove 421. The cutting device 500 includes a cutting blade 510 and a second driver 520 that drives the cutting blade 510 to enter or leave the first slit groove 412 and the second slit groove 422. It can be understood that when the first positioning groove 411 and the corresponding second positioning groove 421 clamp and position a peak portion 11 of the bellows 10, the peak of the peak portion 11 faces the first slit groove 412 and the second slit groove 422. The second driver 520 drives the cutting blade 510 to enter the first slit groove 412 and the second slit groove 422 from the side opening, so as to cut the bellows 10 along the peak of the peak portion 11. Since the first slit groove 412 and the second slit groove 422 respectively penetrate through the first positioning groove 411 and the second positioning groove 421, the peak portion 11 of the bellows 10 to be cut is completely limited, avoiding relative movement.

[0038] See Figure 4, in some embodiments of the present invention, in order to further improve the positioning accuracy of the corrugated pipe 10 and alleviate the problem of relative displacement or deformation caused by only limiting a single wave crest portion 11 of the corrugated pipe 10, the first clamping block 410 has a first semi-circular cavity facing the second clamping block 420. Four first semi-circular ring protrusions 413 are arranged at intervals on the inner peripheral wall of the first semi-circular cavity. Adjacent two of the first semi-circular ring protrusions 413 define a first positioning groove 411. The second clamping block 420 has a second semi-circular cavity opposite to the first semi-circular cavity. Four second semi-circular ring protrusions 423 are arranged at intervals on the inner peripheral wall of the second semi-circular cavity. Adjacent two of the second semi-circular ring protrusions 423 define a second positioning groove 421. The first slit groove 412 penetrates through the first positioning groove 411 located in the middle. The second slit groove 422 penetrates through the second positioning groove 421 located in the middle.

[0039] See Figure 2 , in some embodiments of the present invention, the second driver 520 is a motor. The output shaft of the motor is connected with a mounting beam 530 orthogonal to it. One cutting blade 510 is arranged at each end of the mounting beam 530. The cutting blade 510 has an arc-shaped cutting edge. The two cutting blades 510 are centrosymmetric about the center of the output shaft of the motor. It can be imagined that when the motor drives the mounting beam 530 to rotate 180°, one cutting blade 510 enters or leaves the first slit groove 412 and the second slit groove 422. The setting of the arc-shaped cutting edge is beneficial to gradually increase the contact area between the cutting blade 510 and the corrugated pipe 10, which helps to form a flat cut.

[0040] In some embodiments of the present invention, in order to prevent adhesion between the port of the corrugated pipe 10 and the cutting blade 510 and ensure that the corrugated pipe 10 can fall off smoothly, anti-adhesive coatings are coated on both side surfaces of the cutting blade 510. Among them, the anti-adhesive coating can be a Teflon coating or a titanium alloy coating.

[0041] In some embodiments of the present invention, the first clamping block 410 and the second clamping block 420 are both slidably and vertically arranged on the frame 100. The first driver 430 includes two lifting cylinders respectively driving the first clamping block 410 and the second clamping block 420 to move up and down. At least one of the lifting cylinders is provided with a stroke detector. The stroke detector, the lifting cylinder, and the transmission device 200 are all electrically connected to the control module. It should be noted that when the two lifting cylinders drive the first clamping block 410 and the second clamping block 420 to approach each other respectively, if the peak portion 11 of the corrugated pipe 10 fails to be clamped by the first positioning groove 411 and the second positioning groove 421, that is, the position of the corrugated pipe 10 in the clamping device 400 is deviated. At this time, the moving stroke of the lifting cylinder also does not reach the set stroke. At this time, the control module controls the two lifting cylinders to drive the first clamping block 410 and the second clamping block 420 to move away from each other respectively, and then controls the transmission device 200 to drive the corrugated pipe 10 to advance a distance less than the width dimension of one peak portion 11, and then the two lifting cylinders drive the first clamping block 410 and the second clamping block 420 to approach each other again, so as to automatically correct the position of the corrugated pipe 10, and finally ensure that the cutting can be carried out along the peak portion 11 of the corrugated pipe 10.

[0042] The technical features of the above embodiments can be combined arbitrarily. For the sake of concise description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in this specification.

[0043] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and purposes of the present invention. The scope of the present invention is defined by the claims and their equivalents.

Claims

1. A corrugated pipe cutting-to-length device, characterized in that: include: A frame (100), wherein the frame (100) is provided with a transmission device (200) for driving the corrugated pipe (10) to be transported along its length direction; A sensing unit (300), arranged on the frame (100), for sensing a wave crest (11) or a wave trough (12) of the corrugated tube (10); A clamping device (400) for positioning and clamping the corrugated tube (10); The cutting device (500) cooperates with the clamping device (400) and can cut along the crest portion (11) of the corrugated tube (10).

2. The corrugated pipe cutting-to-length device according to claim 1, characterized in that: The frame (100) is provided with a plurality of guide sleeves (600) arranged at intervals along the conveying direction of the corrugated pipe (10), and the inner diameter of the guide sleeve (600) is matched with the outer diameter of the corrugated pipe (10).

3. The device for cutting corrugated pipe to length according to claim 2, characterized in that: The transmission device (200) comprises a first rotary conveyor belt (210) and a second rotary conveyor belt (220) located between two sections of the guide sleeve (600); the second rotary conveyor belt (220) and the first rotary conveyor belt (210) are arranged at intervals in the vertical direction to define a clamping gap for clamping the corrugated tube (10); the second rotary conveyor belt (220) and the first rotary conveyor belt (210) rotate in opposite directions to drive the corrugated tube (10) to move forward in a preset direction along the axial direction of the guide sleeve (600).

4. The device for cutting corrugated pipe to length according to claim 2, characterized in that: The wall of the guide sleeve (600) is provided with a through hole groove (610) communicating with its inner cavity, and the sensing unit (300) comprises a laser sensor or a photoelectric sensor with a transmitting end arranged facing the through hole groove (610).

5. The corrugated pipe cutting-to-length device according to claim 1, characterized in that: The clamping device (400) comprises a first clamping block (410), a second clamping block (420) and a first driver (430); the first clamping block (410) is provided with at least one first positioning groove (411) corresponding to the wave crest portion (11) of the corrugated tube (10); the second clamping block (420) is provided with a second positioning groove (421) matching the first positioning groove (411) one by one; the first driver (430) drives the first clamping block (410) and the second clamping block (420) to approach each other so that the first positioning groove (411) and the corresponding second positioning groove (421) jointly clamp and position a wave crest portion (11) of the corrugated tube (10).

6. The device for cutting corrugated pipe to length according to claim 5, characterized in that: The widths of the first positioning groove (411) and the second positioning groove (421) are consistent with the width of the crest portion (11) of the corrugated tube (10); the first clamping block (410) is provided with a first knife slit groove (412) with a side opening along the middle position of the width of one of the first positioning grooves (411); the second clamping block (420) is provided with a second knife slit groove (422) with a side opening along the middle position of the width of the corresponding second positioning groove (421); the cutting device (500) comprises a cutting blade (510) and a second driver (520) for driving the cutting blade (510) to enter or leave the first knife slit groove (412) and the second knife slit groove (422).

7. The device for cutting corrugated pipe to length according to claim 6, characterized in that: The first clamping block (410) has a first semicircular cavity facing the second clamping block (420); the inner circumferential wall of the first semicircular cavity is provided with four first semicircular convex strips (413) at intervals; two adjacent first semicircular convex strips (413) define a first positioning groove (411); the second clamping block (420) has a second semicircular cavity opposite to the first semicircular cavity; the inner circumferential wall of the second semicircular cavity is provided with four second semicircular convex strips (423) at intervals; two adjacent second semicircular convex strips (423) define a second positioning groove (421); the first knife slot (412) penetrates the first positioning groove (411) located in the middle; and the second knife slot (422) penetrates the second positioning groove (421) located in the middle.

8. The device for cutting corrugated pipe to length according to claim 6, characterized in that: The second driver (520) is a motor, the output shaft of the motor is connected to a mounting beam (530) orthogonal to the motor, and a cutting blade (510) is disposed at both ends of the mounting beam (530), the cutting blade (510) has an arc-shaped blade edge, and the two cutting blades (510) are symmetrical about the output shaft of the motor.

9. The device for cutting corrugated pipe to length according to claim 8, characterized in that: Both side surfaces of the cutting blade (510) are coated with an anti-stick coating.

10. The device for cutting corrugated pipe to length according to claim 5, characterized in that: The first clamping block (410) and the second clamping block (420) are both slidably lifted and lowered on the frame (100); the first driver (430) comprises two lifting cylinders for respectively driving the first clamping block (410) and the second clamping block (420) to move up and down; at least one of the lifting cylinders is provided with a stroke detector; the stroke detector, the lifting cylinder, and the transmission device (200) are all electrically connected to a control module.

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