Simple craw opening mechanism
Through the design of a simple crop opening mechanism, the cylinder-driven contour clamp is used to clamp and cut the esophagus of poultry necks, which solves the problem of multiple manual handheld shear crop esophagus, realizing full automation and intelligent upgrades of poultry slaughtering, and improving production efficiency and food safety.
Patent Information
- Application Number
- CN202422391404.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-29
- Publication Date
- 2025-08-08
- Estimated Expiration
- 2034-09-29
AI Technical Summary
During poultry slaughtering, the prior art requires multiple manual handheld scissors to shear the esophagus of the crop, resulting in high working intensity, inconsistent quality, prone to occupational diseases and high labor costs, making it difficult to achieve fully automated slaughter.
A simple crop opening mechanism is adopted, including a first Y-axis drive module, a first contour clamp and a scissor module, and the poultry neck is clamped by a cylinder-driven contour clamp and cut off the esophagus to achieve fully automatic crop opening.
It has realized full automation of the poultry slaughtering industry, improved production efficiency, ensured the quality of the upper esophagus of the crop and cut off the crop, reduced labor intensity and labor costs, and improved food production safety and economic benefits.
Smart Images

Figure CN223195439U_ABST
Abstract
Description
Technical field:
[0001] The utility model relates to the technical field of poultry slaughtering, in particular to a simple crop opening mechanism. Background technology:
[0002] As people's requirements for the quality of poultry products and hygiene and epidemic prevention become increasingly higher, chickens are no longer supplied to the market simply as live poultry, but are slaughtered, divided and packaged in batches by production companies and then put on the market as semi-finished products. This method can effectively improve the return rate of breeding companies.
[0003] Currently, poultry slaughterhouses slaughter chickens by first slitting their throats to bleed them, followed by depilation and evisceration. However, crop opening is the first step in the evisceration process. Domestically, non-white-feathered chickens are slaughtered manually using scissors or knives to cut the esophagus above the crop, allowing the viscera to be pulled out from the body for further processing. In a poultry slaughtering line, with a production rate of 4,000-7,000 birds per hour, three to five workers are required. Each worker performs tens of thousands of cuts per day, resulting in high workload and inconsistent crop opening quality. Skilled operators are also required, which can lead to occupational diseases and high labor costs. Companies are urgently seeking automated alternatives to poultry slaughtering to achieve fully automated poultry slaughtering and improve production efficiency.
[0004] In view of this, the inventors propose the following technical solutions. Utility model content:
[0005] The purpose of the utility model is to overcome the deficiencies of the prior art and provide a simple crop opening mechanism.
[0006] In order to solve the above technical problems, the utility model adopts the following technical solutions: the simple crop opening mechanism includes a first Y-axis drive module, a first profiling fixture installed on the first Y-axis drive module and a scissors module located next to the first profiling fixture and used to cut the esophagus to open the crop, a second Y-axis drive module located next to the first Y-axis drive module, and a second profiling fixture installed on the second Y-axis drive module and corresponding to the first profiling fixture. The first profiling fixture and the second profiling fixture constitute profiling fixtures for clamping and positioning the necks of poultry, and the opposite surfaces of the first profiling fixture and the second profiling fixture are respectively provided with a first clamping groove and a second clamping groove.
[0007] Furthermore, the above technical solution also includes a machine base, a first vertical pole installed on one side of the machine base through a first Z-axis drive module, and a second vertical pole installed on the other side of the machine base through a second Z-axis drive module and distributed opposite to the first vertical pole; the first Y-axis drive module is installed at the upper end of the first vertical pole; and the second Y-axis drive module is installed at the upper end of the second vertical pole.
[0008] Furthermore, in the above technical solution, the first Y-axis driving module and the second Y-axis driving module are both cylinders.
[0009] Furthermore, in the above technical solution, the front end of the first profiling fixture is provided with a first guide seat and a second guide seat distributed in an eight-shaped shape on the outside of the first clamping groove, and the first guide seat and the second guide seat respectively have a first guide groove and a second guide groove, and the front end of the second profiling fixture is provided with a first guide piece and a second guide piece distributed in an eight-shaped shape on the outside of the second clamping groove. When the first profiling fixture and the second profiling fixture are relatively close to each other, the first guide piece and the second guide piece are respectively inserted into the first guide groove and the second guide groove.
[0010] Furthermore, in the above technical solution, the lower end of the first contour clamp is further provided with a posture guiding portion protruding outward and used to guide the posture of the base of the poultry neck, and the posture guiding portion has a posture guiding groove connected to the first clamping groove.
[0011] Furthermore, in the above technical solution, the lower end of the second contoured clamp is also provided with a pushing protrusion that protrudes forward and is used to push out or squeeze out the esophagus at the neck of the poultry, and the pushing protrusion is provided with an airtight opening that passes through the front and rear end surfaces and for the end of the scissors module to pass through.
[0012] Furthermore, in the above technical solution, the scissors module includes a cylinder installed on the outside of the first contoured fixture in a manner that can adjust the front and rear positions, a bracket installed on the slide outside the cylinder, a sliding seat installed in the bracket in a slidable manner, a sixth spring installed between the sliding seat and the bracket, a first L-shaped blade and a second L-shaped blade installed on the front end of the sliding seat in a rotatable manner through a rotating shaft screw, a linkage block fixed to the rear end of the sliding seat, a guide plate installed at the rear end of the cylinder, and a pull rod screw that passes through the guide plate and is connected to the linkage block in a manner that can adjust the relative position in the front and rear directions. A first shaft rod and a second shaft rod are respectively provided on both sides of the front end of the bracket, and a first U-shaped opening and a second U-shaped opening are respectively provided on the outside of the first L-shaped blade and the second L-shaped blade. The first U-shaped opening is sleeved on the outer periphery of the first shaft rod, and the second U-shaped opening is sleeved on the outer periphery of the second shaft rod.
[0013] Furthermore, in the above technical solution, the cylinder and the first profiling fixture are provided with a strip hole on the outside, and the first screw passes through the strip hole and is screwed fixed to the thread groove, so that the scissors module is installed on the outside of the first profiling fixture and the relative position can be adjusted.
[0014] Furthermore, in the above technical solution, a cross bar portion is provided in the middle of the bracket; the sliding seat is U-shaped, which is sleeved on the outer periphery of the cross bar portion and can slide back and forth, and the linkage block is fixed on the rear side of the sliding seat and surrounded by the outer periphery of the cross bar portion; one end of the sixth spring is passed through the transverse groove of the cross bar portion, and the other end of the sixth spring is passed through the sliding seat.
[0015] Furthermore, in the above technical solution, the pull rod screw is connected to the guide plate through a threaded connection, and the relative position can be adjusted, or a nut is provided in the guide plate, and the nut and the pull rod screw are spirally installed, and the relative position can be adjusted.
[0016] After adopting the above technical solution, the present invention has the following beneficial effects compared with the prior art: when the present invention is in operation, the first Y-axis drive module and the second Y-axis drive module respectively drive the first profiling clamp and the second profiling clamp to move relatively close to each other, and the first clamping groove of the first profiling clamp and the second clamping groove of the second profiling clamp are respectively clamped on the dorsal side and the ventral side of the base of the poultry neck, thereby ensuring that the poultry does not shake and achieving the positioning effect; finally, the scissors module penetrates the skin of the poultry neck to cut the esophagus at the upper end of the crop inside the skin, thereby achieving the purpose of opening the crop and facilitating the removal of internal organs later. In other words, the structure of the present invention can fully automatically and unmannedly realize the important pre-process "crop opening" in the poultry slaughtering industry, subverting the traditional method of multiple manual hand-held scissors cutting the crop esophagus, creating a new pattern for the intelligent upgrading of the poultry slaughtering industry, greatly improving production efficiency, while ensuring the quality of crop opening and cutting the esophagus at the upper end of the crop, and is beneficial to the improvement of food production safety and efficiency, creating certain economic and social value. Description of the drawings:
[0017] Figure 1 It is a three-dimensional diagram of the utility model;
[0018] Figure 2 It is a three-dimensional diagram of the present invention from another perspective;
[0019] Figure 3 This is an assembly diagram of the first profiling fixture, the scissors module, and the first Y-axis drive module in the present invention;
[0020] Figure 4 This is an assembly drawing of the first profiling fixture, the scissor module, and the first Y-axis drive module in the present invention from another perspective;
[0021] Figure 5It is a three-dimensional diagram of the scissors module in the utility model;
[0022] Figure 6 It is a cross-sectional view of the scissors module in the utility model;
[0023] Figure 7 This is a three-dimensional exploded view of the scissors module in the utility model;
[0024] Figure 8 This is an assembly diagram of the second profiling fixture and the second Y-axis drive module in the present invention;
[0025] Figure 9 This is an exploded view of the assembly of the second profiling fixture and the second Y-axis drive module in the present invention. Specific implementation method:
[0026] The present invention will be further described below with reference to specific embodiments and accompanying drawings.
[0027] See Figure 1-9 As shown, a simple crop opening mechanism is characterized in that it includes a first Y-axis drive module 16, a first profiling fixture 5 installed on the first Y-axis drive module 16, and a scissors module 6 located next to the first profiling fixture 5 and used to cut the esophagus to open the crop, a second Y-axis drive module 17 located next to the first Y-axis drive module 16, and a second profiling fixture 7 installed on the second Y-axis drive module 17 and corresponding to the first profiling fixture 5. The first profiling fixture 5 and the second profiling fixture 7 constitute profiling fixtures for clamping and positioning the necks of poultry, and the opposite surfaces of the first profiling fixture 5 and the second profiling fixture 7 are respectively provided with a first clamping groove 50 and a second clamping groove 70. During operation, the first Y-axis drive module 16 and the second Y-axis drive module 17 drive the first profiling fixture 5 and the second profiling fixture 7 to move closer to each other, and the first clamping groove 50 of the first profiling fixture 5 and the second clamping groove 70 of the second profiling fixture 7 are respectively clamped on the dorsal side and the ventral side of the base of the poultry's neck, thereby ensuring that the poultry does not shake and achieving the positioning effect; finally, the scissor module 6 penetrates the skin of the poultry's neck to cut the esophagus at the upper end of the crop inside the skin, thereby achieving the purpose of opening the crop and facilitating the removal of internal organs later. In other words, the structure of the utility model can fully automatically and unmannedly realize the important pre-process of "crop opening" in the poultry slaughtering industry, subverting the traditional method of multiple manual hand-held scissors to cut the crop esophagus, creating a new pattern for the intelligent upgrading of the poultry slaughtering industry, greatly improving production efficiency, while ensuring the quality of crop opening and cutting the esophagus at the upper end of the crop, and promoting the improvement of food production safety and efficiency, creating certain economic and social value.
[0028] In this embodiment, the poultry is chicken.
[0029] The crop opening mechanism 1 also includes a base 11, a first upright pole 13 mounted on one side of the base 11 via a first Z-axis drive module 12, and a second upright pole 15 mounted on the other side of the base 11 and opposite to the first upright pole 13 via a second Z-axis drive module 14. The first Y-axis drive module 16 is mounted on the upper end of the first upright pole 13, and the second Y-axis drive module 17 is mounted on the upper end of the second upright pole 15. Both the first Z-axis drive module 12 and the first Z-axis drive module 14 are driven by servo motors.
[0030] When the crop opening mechanism 1 is working, the first Z-axis driving module 12 and the second Z-axis driving module 14 drive the first profiling fixture 5 and the second profiling fixture 7 to rise to corresponding heights to meet different crop opening requirements.
[0031] In this embodiment, the first clamping groove 50 of the first profiling fixture 5 and the second clamping groove 70 of the second profiling fixture 7 are made in the shape of chicken necks, which can take into account different types of chickens (different breeds of chickens have different sizes and lengths of necks and bodies).
[0032] The first Y-axis driving module 16 and the second Y-axis driving module 17 are both cylinders, which have simple structures and low costs.
[0033] The front end of the first profiling fixture 5 is provided with a first guiding seat 51 and a second guiding seat 52 distributed in an eight-shaped manner on the outside of the first clamping groove 50, and the first guiding seat 51 and the second guiding seat 52 respectively have a first guiding groove 511 and a second guiding groove 521. The front end of the second profiling fixture 7 is provided with a first guiding piece 71 and a second guiding piece 72 distributed in an eight-shaped manner on the outside of the second clamping groove 70. When the first profiling fixture 5 and the second profiling fixture 7 are relatively close to each other, the first guiding piece 71 and the second guiding piece 72 are respectively inserted into the first guiding groove 511 and the second guiding groove 521, thereby ensuring that the first profiling fixture 5 and the second profiling fixture 7 can be guided close together to ensure the purpose of clamping the necks of the poultry with each other. Its operation is smoother and more precise, and jamming is avoided.
[0034] The lower end of the first contouring clamp 5 is also provided with a protruding, outwardly extending, position-correcting portion 53 for correcting the position of the base of the poultry's neck. This position-correcting portion 53 includes a position-correcting groove 531 that communicates with the first clamping slot 50. The position-correcting groove 531 of the position-correcting portion 53 is designed to contact and correct the position of the base of the poultry's neck, adjusting the position of the poultry while suspended on the conveyor chain and facilitating effective esophageal shearing. The base of poultry necks is generally large, and this varies significantly between different poultry species. Therefore, the position-correcting portion 53 is added to accommodate the position correction of poultry necks of varying sizes.
[0035] The lower end of the second contoured fixture 7 is further provided with a forward-projecting protrusion 73 for pushing out or extruding the esophagus at the poultry's neck. This protrusion 73 is provided with a clearance opening 731 that extends through the front and rear surfaces and allows the end of the scissor module 6 to pass through. This protrusion 73 is used to separate and squeeze the esophagus at the upper end of the crop from the poultry's neck, thereby improving the success rate and the quality of the cut when the scissor module subsequently cuts the esophagus at the upper end of the crop, thereby preventing the cut from being too large.
[0036] The scissors module 6 includes a cylinder 61 mounted on the outside of the first profiling fixture 5 in a manner that can adjust the front and rear positions, a bracket 62 mounted on the slide 611 outside the cylinder 61, a sliding seat 63 mounted in a slidable manner in the bracket 62, a sixth spring 60 mounted between the sliding seat 63 and the bracket 62, a first L-shaped blade 65 and a second L-shaped blade 66 mounted on the front end of the sliding seat 63 in a rotatable manner by a rotating shaft screw 64, a linkage block 67 fixed to the rear end of the sliding seat 63, and a spring 68 mounted on the cylinder 61. The guide plate 68 at the rear end and the pull rod screw 69 that passes through the guide plate 68 and is connected to the linkage block 67 in a manner that the relative position can be adjusted in the front and rear directions, the first shaft rod 621 and the second shaft rod 622 are respectively provided on both sides of the front end of the bracket 62, and the outer sides of the first L-shaped blade 65 and the second L-shaped blade 66 (i.e., the handle part) are respectively provided with a first U-shaped opening 651 and a second U-shaped opening 661, the first U-shaped opening 651 is sleeved on the outer periphery of the first shaft rod 621, and the second U-shaped opening 661 is sleeved on the outer periphery of the second shaft rod 622. The sliding seat 63 is ejected outward (i.e., forward) relative to the bracket 62 under the elastic force of the sixth spring 60. After the slide 611 outside the cylinder 61 drives the bracket 62 backward, the sliding seat 63 is pulled by the pull rod screw 69 and cannot move. However, the first L-shaped blade 65 and the second L-shaped blade 66 can rotate relative to the front end of the sliding seat 63. At this time, as the bracket 62 moves backward, the first U-shaped opening 651 of the first L-shaped blade 65 and the second U-shaped opening 661 of the second L-shaped blade 66 are driven backward. The first L-shaped blade 65 and the second L-shaped blade 66 are relatively open due to the restraining action of the first U-shaped opening 651 and the second U-shaped opening 661 and the first and second shafts 621 and 622. Similarly, when the slide 611 outside the cylinder 61 drives the bracket 62 forward, the first L-shaped blade 65 and the second L-shaped blade 66 close together to achieve the shearing operation. The function of the sixth spring 60 is to drive the sliding seat 63 to extend forward, that is, the sliding seat 63 can float back and forth relative to the bracket 62.
[0037] The pull rod screw 69 is threadedly connected to the guide plate 68, allowing for adjustment of their relative position. Alternatively, a nut 681 is provided within the guide plate 68, which is screwed onto the pull rod screw 69 to allow for adjustment of their relative position. Adjusting the relative position of the pull rod screw 69 and the guide plate 68 further adjusts the position of the linkage block 67 and the sliding seat 63 relative to the bracket 62, thereby adjusting the opening size and cutting depth of the first and second L-shaped blades 65 and 66 to meet different usage requirements.
[0038] The linkage block 67 is provided with a thread groove, and the end of the pull rod screw 69 is provided with a thread section, which is spirally installed to be connected with the thread groove.
[0039] The cylinder 61 is provided with a threaded groove 610 on the outside, and the first profiling fixture 5 is provided with a strip-shaped hole 501 on the outside. A first screw passes through the strip-shaped hole 501 and is screwed into the threaded groove 610, thereby ensuring that the scissors module 6 is stably mounted on the outside of the first profiling fixture 5. When the relative position needs to be adjusted, the first screw is loosened and moved back and forth through the strip-shaped hole 501 to adjust the front-to-back position of the cylinder 61 relative to the first profiling fixture 5. After the adjustment is completed, the first screw is tightened, making the operation extremely convenient.
[0040] A crossbar 620 is provided in the middle of the bracket 62. The sliding seat 63 is U-shaped and fits around the crossbar 620, allowing it to slide forward and backward. The linkage block 67 is fixed to the rear side of the sliding seat 63 and surrounds the crossbar 620. One end of the sixth spring 60 is inserted into the transverse groove 603 of the crossbar 620. The other end of the sixth spring 60 is inserted into the sliding seat 63.
[0041] The first baffle 601 and the second baffle 602 are respectively installed on the upper ends of the first shaft 621 and the second shaft 622 by the third screw and the fourth screw, and the outer side (i.e., the handle part) lower surface of the first L-shaped blade 65 and the second L-shaped blade 66 is attached to the upper surface of the front end of the sliding seat 63, and the first baffle 601 and the second baffle 602 are respectively placed on the outer side (i.e., the handle part) upper surface of the first L-shaped blade 65 and the second L-shaped blade 66, so as to prevent the first L-shaped blade 65 and the second L-shaped blade 66 from falling out relative to the first shaft 621 and the second shaft 622, thereby ensuring the stability and quality of the assembly structure.
[0042] In summary, when the present invention is in operation, the first Y-axis drive module 16 and the second Y-axis drive module 17 respectively drive the first profiling fixture 5 and the second profiling fixture 7 to move relatively close to each other, and the first clamping groove 50 of the first profiling fixture 5 and the second clamping groove 70 of the second profiling fixture 7 are respectively clamped on the dorsal side and the ventral side of the base of the poultry neck, thereby ensuring that the poultry does not shake and achieving the positioning effect; finally, the scissor module 6 penetrates the skin of the poultry neck to cut the esophagus at the upper end of the crop inside the skin, thereby achieving the purpose of opening the crop and facilitating the removal of internal organs later. In other words, the structure of the present invention can fully automatically and unmannedly realize the important pre-process "crop opening" in the poultry slaughtering industry, subverting the traditional method of multiple manual hand-held scissors to cut the crop esophagus, creating a new pattern for the intelligent upgrading of the poultry slaughtering industry, greatly improving production efficiency, while ensuring the quality of crop opening and cutting the esophagus at the upper end of the crop, and is beneficial to the improvement of food production safety and efficiency, creating certain economic and social value.
[0043] Of course, the above description is only a specific embodiment of the present invention and is not intended to limit the scope of implementation of the present invention. Any equivalent changes or modifications made based on the structure, features and principles described in the scope of the patent application of the present invention should be included in the scope of the patent application of the present invention.
Claims
1. Simple crop opening mechanism, characterized by: The invention comprises a first Y-axis driving module (16), a first profiling fixture (5) mounted on the first Y-axis driving module (16), a scissor module (6) located beside the first profiling fixture (5) and used for cutting the esophagus to open the crop, a second Y-axis driving module (17) located beside the first Y-axis driving module (16), and a second profiling fixture (7) mounted on the second Y-axis driving module (17) and corresponding to the first profiling fixture (5). The first profiling fixture (5) and the second profiling fixture (7) constitute a profiling fixture for clamping and positioning the neck of a poultry, and the opposing surfaces of the first profiling fixture (5) and the second profiling fixture (7) are respectively provided with a first clamping groove (50) and a second clamping groove (70).
2. The simplified crop opening mechanism according to claim 1, characterized in that: The machine also includes a base (11), a first vertical pole (13) installed on one side of the base (11) via a first Z-axis drive module (12), and a second vertical pole (15) installed on the other side of the base (11) via a second Z-axis drive module (14) and distributed opposite to the first vertical pole (13); the first Y-axis drive module (16) is installed on the upper end of the first vertical pole (13); and the second Y-axis drive module (17) is installed on the upper end of the second vertical pole (15).
3. The simplified crop opening mechanism according to claim 1, characterized in that: The first Y-axis driving module (16) and the second Y-axis driving module (17) are both cylinders.
4. The simplified crop opening mechanism according to claim 1, characterized in that: The front end of the first profiling fixture (5) is provided with a first guiding seat (51) and a second guiding seat (52) distributed in an eight-shaped manner outside the first clamping groove (50), and the first guiding seat (51) and the second guiding seat (52) respectively have a first guiding groove (511) and a second guiding groove (521). The front end of the second profiling fixture (7) is provided with a first guiding piece (71) and a second guiding piece (72) distributed in an eight-shaped manner outside the second clamping groove (70). When the first profiling fixture (5) and the second profiling fixture (7) are relatively close to each other, the first guiding piece (71) and the second guiding piece (72) are respectively inserted into the first guiding groove (511) and the second guiding groove (521).
5. The simplified crop opening mechanism according to claim 1, characterized in that: The lower end of the first profiling clamp (5) is also provided with a posture guiding portion (53) protruding outward and used to correct the posture of the base of the poultry neck. The posture guiding portion (53) has a posture guiding groove (531) connected to the first clamping groove (50).
6. The simplified crop opening mechanism according to claim 1, characterized in that: The lower end of the second profiling clamp (7) is also provided with a forward-projecting protrusion (73) for pushing out or squeezing out the esophagus at the neck of the poultry, and the protrusion (73) is provided with an air escapement (731) that passes through the front and rear end surfaces and allows the end of the scissor module (6) to pass through.
7. The simplified crop opening mechanism according to any one of claims 1 to 6, characterized in that: The scissors module (6) comprises a cylinder (61) mounted on the outside of the first profiling fixture (5) in a manner that allows for front and rear position adjustment, a bracket (62) mounted on a slide (611) on the outside of the cylinder (61), a sliding seat (63) mounted in the bracket (62) in a slidable manner, a sixth spring (60) mounted between the sliding seat (63) and the bracket (62), a first L-shaped blade (65) and a second L-shaped blade (66) mounted on the front end of the sliding seat (63) in a rotatable manner by means of a rotating shaft screw (64), a linkage block (67) fixed to the rear end of the sliding seat (63), and a spring (61) mounted on the sliding seat (63). A guide plate (68) is provided at the rear end of the cylinder (61), and a pull rod screw (69) passes through the guide plate (68) and is connected to the linkage block (67) in a manner that allows the relative position to be adjusted in the front-back direction. A first shaft rod (621) and a second shaft rod (622) are provided on both sides of the front end of the bracket (62). A first U-shaped opening (651) and a second U-shaped opening (661) are provided on the outer sides of the first L-shaped blade (65) and the second L-shaped blade (66). The first U-shaped opening (651) is sleeved on the outer periphery of the first shaft rod (621), and the second U-shaped opening (661) is sleeved on the outer periphery of the second shaft rod (622).
8. The simplified crop opening mechanism according to claim 7, characterized in that: A thread groove (610) is provided on the outside of the cylinder (61), and a strip hole (501) is provided on the outside of the first profiling fixture (5). A first screw passes through the strip hole (501) and is screw-fixed with the thread groove (610), so that the scissors module (6) is installed on the outside of the first profiling fixture (5), and the relative position can be adjusted.
9. The simplified crop opening mechanism according to claim 7, characterized in that: A crossbar portion (620) is provided in the middle of the bracket (62); the sliding seat (63) is U-shaped, sleeved on the periphery of the crossbar portion (620), and can slide forward and backward; the linkage block (67) is fixed to the rear side of the sliding seat (63) and surrounded by the periphery of the crossbar portion (620); one end of the sixth spring (60) is inserted into the transverse groove (603) of the crossbar portion (620), and one end of the sixth spring (60) is inserted into the sliding seat (63) at the other end.
10. The simplified crop opening mechanism according to claim 7, characterized in that: The pull rod screw (69) is connected to the guide plate (68) by a threaded connection, and the relative position can be adjusted. Alternatively, a nut (681) is provided in the guide plate (68), and the nut (681) and the pull rod screw (69) are screwed together, and the relative position can be adjusted.