Nut tapping device

Abstract

The invention relates to the technical field of nut tapping, in particular to a nut tapping device which comprises a workbench, a hydraulic rod is mounted at the top of the workbench, a connecting block is arranged at the top of the hydraulic rod, and a reversing assembly is arranged in the connecting block; the reversing assembly comprises a driving component and a reversing component, the driving component comprises a reversing air cylinder, the reversing air cylinder is located on one side of the connecting block, the output end of the reversing air cylinder is fixedly connected with a reversing block, a sliding groove is formed in one end of the connecting block, the reversing block is in sliding connection with the sliding groove, and the power transmission direction is changed through the reversing air cylinder in the reversing assembly. According to the utility model, current abrupt change, electromagnetic loss and mechanical wear caused by frequent positive and negative rotation of the motor are avoided, instant large current generated during positive and negative rotation switching can be reduced, considerable electric charge cost can be saved through long-term accumulation in large-scale nut production, the service life of the tapping motor is prolonged, and the maintenance cost and the overall energy consumption are reduced.

Description

Technical Field

[0001] The invention relates to the technical field of nut tapping, in particular to a nut tapping device. Background Art

[0002] A nut is a nut that is screwed together with a bolt or screw for fastening. It is a component that all manufacturing machinery must use. According to the different materials, it is divided into several types, such as carbon steel, stainless steel, and non-ferrous metals (such as copper). Nuts are usually hexagonal, followed by square. During the nut processing, the inside needs to be tapped. At this time, a nut tapping device is needed to tap the nut.

[0003] When the existing nut tapping device is in use, the motor needs to rotate forward and reverse to achieve tapping and threading of the nut. When the motor rotates forward, it drives the tap to rotate and cut into the nut to perform the tapping operation and form a thread. After the tapping is completed, in order to smoothly withdraw the tap from the formed thread and avoid damaging the thread and the tap, the motor needs to be reversed. In some large-scale nut production, large-scale production is carried out continuously for a long time, and the motor frequently rotates forward and reverse, resulting in a rapid change in the direction of the magnetic field, which increases the motor current and heat generation, resulting in increased power consumption and reduced motor life, which increases the probability of error in the tapping system, thereby affecting the tapping quality and production efficiency. Summary of the invention

[0004] The object of the present invention is to provide a nut tapping device to solve the problems raised in the above background technology.

[0005] To achieve the above object, the present invention provides the following technical solutions: A nut tapping device comprises a workbench, a hydraulic rod is installed on the top of the workbench, a connecting block is arranged on the top of the hydraulic rod, and a reversing assembly is arranged inside the connecting block; The reversing assembly includes a driving component and a reversing component. The driving component includes a reversing cylinder. The reversing cylinder is located on one side of the connecting block. The output end of the reversing cylinder is fixedly connected with the reversing block. A slide groove is provided at one end of the connecting block. The reversing block is slidably connected with the slide groove. One end of the reversing block extends through the interior of the connecting block and is connected with a bearing. The reversing block is used to drive the reversing component to perform reversing. The reversing component includes a connecting rod, a transmission rod and a rotating rod. The connecting rod, the transmission rod and the rotating rod are all rotatably connected to the connecting block. The ends of the rotating rod and the connecting rod that are close to each other are fixedly connected with spline shafts. Sleeves are provided on the outside of the two spline shafts, and the bearing is connected to one end of the sleeve.

[0006] The reversing component also includes an output gear, a plurality of support rods are fixedly connected to the bottom of the output gear, an annular groove is opened inside the connecting block, and the plurality of support rods are slidably connected to the annular groove, and the output gear is located outside the connecting rod and does not contact the connecting rod.

[0007] Both ends of the sleeve are provided with external splines and internal splines, a spline hole is opened on the inner side of the output gear, the internal splines on the sleeve form a spline connection with the two spline shafts respectively, and the external splines of the sleeve form a spline connection with the spline hole on the inner side of the output gear.

[0008] The connecting block is internally rotatably connected with an idler wheel, one end of the transmission rod and the rotating rod are fixedly connected with a second transmission gear, the two second transmission gears are meshed with each other, one end of the transmission rod away from the second transmission gear is fixedly connected with the first transmission gear, and both ends of the idler wheel are respectively meshed with the output gear and the first transmission gear.

[0009] A tapping motor is arranged on the top of the connection block, the output end of the tapping motor is fixedly connected to the rotating rod, and one end of the connection rod extends through and extends to the outside of the connection block and is fixedly connected with a tap.

[0010] The change of power transmission direction is achieved through the reversing cylinder in the reversing assembly, which avoids the current mutation, electromagnetic loss and mechanical wear caused by the frequent forward and reverse rotation of the motor, and reduces the instantaneous large current generated when switching between forward and reverse rotation. In large-scale nut production, the long-term accumulation can save considerable electricity costs, extend the service life of the tapping motor, and reduce maintenance costs and overall energy consumption.

[0011] A frame is arranged on the top of the workbench, a turntable is rotatably connected to the top of the frame, a rotary motor is arranged on the bottom of the frame, and an output end of the rotary motor is fixedly connected to a shaft inside the turntable.

[0012] A plate body is provided at one end of the workbench close to the turntable, a slide rail is provided on one side of the plate body, a clamping cylinder is provided on one side of the slide rail, a slider at the rear side of the clamping cylinder is slidably connected to the slide rail, and a grab clamp is fixedly connected to the bottom of the clamping cylinder.

[0013] The rotating motor can drive the turntable to rotate. When the turntable rotates, it can carry multiple nuts for loading, tapping and unloading in sequence, which improves the utilization rate of the equipment and is suitable for large-scale production needs.

[0014] A plurality of fixing plates are arranged above the turntable, a placing block is arranged above each of the fixing plates, and a material unloading assembly is arranged inside the plurality of placing blocks.

[0015] There are multiple groups of unloading components, each group of unloading components includes a unloading cylinder, which is located on one side of the placing block, a placing cavity is opened inside the placing block, a push plate is slidably connected inside the placing cavity, the output end of the unloading cylinder is fixedly connected to the push plate, a flexible block is fixedly connected to the front side of the push plate, push rods are fixedly connected on both sides of the push plate, the front ends of the two push rods are fixedly connected to connecting plates, oblique grooves are opened inside the two connecting plates, sliding rods are slidably connected inside the two oblique grooves, a sliding groove is opened inside the placing block, a limit block is slidably connected inside the sliding groove, the two ends of the limit block are respectively fixedly connected to the corresponding sliding rods, and a baffle is connected above the limit block.

[0016] The blanking component can automatically blank the nuts after tapping, reducing the need for manual intervention and adjustment, simplifying the workflow and reducing labor intensity.

[0017] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention realizes the change of power transmission direction through the reversing cylinder in the reversing assembly, avoids the current mutation, electromagnetic loss and mechanical wear caused by the frequent forward and reverse rotation of the motor, reduces the instantaneous large current generated during the forward and reverse switching, and can save considerable electricity costs in the long term in large-scale nut production, and prolongs the service life of the tapping motor, reducing maintenance costs and overall energy consumption; 2. The present invention adopts a stable unidirectional rotation power output, which reduces the unstable factors in the tapping and threading process that may be caused by the switching of the tapping motor, and improves the accuracy of nut tapping and threading; 3. The present invention sets a baffle in the blanking assembly. During tapping, the baffle fixes the nut to prevent the nut from displacement or shaking during the tapping process. After the tapping is completed, the baffle will drop to ensure orderly blanking of the nut. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the overall structure of the present invention; Figure 2 is a side view of the present invention; Figure 3 It is a schematic diagram of the internal structure of the connection block of the present invention; Figure 4 A plan view of the switching assembly of the present invention; Figure 5 It is a schematic diagram of the connection structure between the connecting rod and the tap of the present invention; Figure 6 It is a schematic diagram of the connection structure between the fixing plate and the connecting block of the present invention; Figure 7 It is a schematic diagram of the connection structure between the push plate and the flexible block of the present invention; Figure 8It is a schematic diagram of the connection structure between the connection plate and the slider of the present invention; Fig. 9 For the present invention Figure 5 A magnified view of the structure in the middle.

[0019] In the accompanying drawings, the components represented by the reference numerals are listed as follows: 1. Workbench; 2. Frame; 3. Rotating motor; 4. Turntable; 5. Hydraulic rod; 6. Connecting block; 7. Tapping motor; 8. Reversing cylinder; 9. Reversing block; 10. Connecting rod; 11. Tap; 12. Transmission rod; 13. Rotating rod; 14. Idle wheel; 15. Sleeve; 16. First transmission gear; 17. Second transmission gear; 18. Support rod; 19. Clamping cylinder; 20. Grab; 21. Slide rail; 22. Fixed plate; 23. Placement block; 24. Unloading cylinder; 25. Push plate; 26. Flexible block; 27. Baffle; 28. Connecting plate; 29. ​​Slide; 30. Limit block; 31. Spline shaft; 32. Output gear; 33. Bearing; 34. Push rod. DETAILED DESCRIPTION

[0020] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] like Figure 1-Figure 9 A nut tapping device shown in the figure comprises a workbench 1, a hydraulic rod 5 is installed on the top of the workbench 1, a connecting block 6 is arranged on the top of the hydraulic rod 5, and a reversing assembly is arranged inside the connecting block 6; The reversing assembly includes a driving component and a reversing component. The driving component includes a reversing cylinder 8. The reversing cylinder 8 is located on one side of the connecting block 6. The output end of the reversing cylinder 8 is fixedly connected with a reversing block 9. A slide groove is provided at one end of the connecting block 6. The reversing block 9 is slidably connected with the slide groove. One end of the reversing block 9 extends through the interior of the connecting block 6 and is connected with a bearing 33. The reversing block 9 is used to drive the reversing component to perform reversing. The reversing component includes a connecting rod 10, a transmission rod 12 and a rotating rod 13. The connecting rod 10, the transmission rod 12 and the rotating rod 13 are all rotatably connected to the connecting block 6. The ends of the rotating rod 13 and the connecting rod 10 that are close to each other are fixedly connected with a spline shaft 31. A sleeve 15 is provided on the outside of the two spline shafts 31, and a bearing 33 is connected to one end of the sleeve 15.

[0022] By setting up the reversing component, the losses and problems caused by the frequent forward and reverse rotation of the tapping motor 7 are avoided. The change of power transmission direction is achieved through the reversing cylinder 8 in the reversing component, which avoids the current mutation, electromagnetic loss and mechanical wear caused by the frequent forward and reverse rotation of the motor and avoids the instantaneous large current during the forward and reverse switching. In the large-scale nut production, the long-term accumulation can save considerable electricity costs, extend the service life of the tapping motor 7, and reduce maintenance costs and overall energy consumption.

[0023] like Figure 3-Figure 5 As shown, the reversing component also includes an output gear 32, a plurality of support rods 18 are fixedly connected to the bottom of the output gear 32, an annular groove is provided inside the connecting block 6, and the plurality of support rods 18 are slidably connected to the annular groove, the output gear 32 is located outside the connecting rod 10 and does not contact the connecting rod 10, both ends of the sleeve 15 are provided with external splines and internal splines, a spline hole is provided on the inner side of the output gear 32, the internal splines on the sleeve 15 are respectively splined with the two spline shafts 31, the external splines of the sleeve 15 are splined with the spline holes on the inner side of the output gear 32, the inner side of the connecting block 6 is rotatably connected with an idler gear 14, one end of the transmission rod 12 and the rotating rod 13 are fixedly connected with the second transmission gear 17, the two second transmission gears 17 are meshed, the end of the transmission rod 12 away from the second transmission gear 17 is fixedly connected with the first transmission gear 16, and the two ends of the idler gear 14 are respectively meshed with the output gear 32 and the first transmission gear 16.

[0024] When the nut is tapped, the sleeve 15 is initially located between the connecting rod 10 and the rotating rod 13 (eg Fig. 9 As shown), at this time, the tapping motor 7 drives the rotating rod 13 to rotate, because the internal spline of the sleeve 15 is spline-connected with the spline shaft 31 on the connecting rod 10 and the rotating rod 13, so when the tapping motor 7 is running, the tap 11 below the connecting rod 10 is driven to rotate forward through the rotating rod 13 to perform a tapping operation on the nut. At this time, the second transmission gear 17 above the rotating rod 13 drives the second transmission gear 17 on the transmission rod 12 to rotate, and the transmission rod 12 drives the first transmission gear 16 to rotate, and then drives the output gear 32 to rotate through the idler gear 14. Because the output gear 32 is not in contact with the connecting rod 10 at this time, the output gear 32 is in an idling state; When the thread is withdrawn, the reversing cylinder 8 drives the reversing block 9 to move downward, and the internal spline of the sleeve 15 is disengaged from the spline shaft 31 on the rotating rod 13. At this time, the external spline of the sleeve 15 forms a spline connection with the spline hole of the output gear 32. When the power of the tapping motor 7 is transmitted to the output gear 32 during forward rotation, because the external spline of the sleeve 15 is spline-connected with the output gear 32, and because of the existence of the idler wheel 14, when the output gear 32 rotates, it will drive the connecting rod 10 to rotate in the opposite direction, thereby withdrawing the thread from the nut.

[0025] The stable unidirectional rotation power output reduces the unstable factors in the tapping and threading process that may be caused by the direction switching of the tapping motor 7, thereby ensuring the accuracy of the nut tapping and threading.

[0026] like Figure 3-Figure 4 As shown, a tapping motor 7 is provided on the top of the connecting block 6, and the output end of the tapping motor 7 is fixedly connected to the rotating rod 13, and one end of the connecting rod 10 extends through and extends to the outside of the connecting block 6 and is fixedly connected to a tap 11.

[0027] like Figure 1-Figure 2 As shown, a frame 2 is provided on the top of the workbench 1, and a turntable 4 is rotatably connected to the top of the frame 2. A rotating motor 3 is provided at the bottom of the frame 2. The output end of the rotating motor 3 is fixedly connected to the shaft inside the turntable 4. A plate is provided at one end of the workbench 1 close to the turntable 4, and a slide rail 21 is provided on one side of the plate. A clamping cylinder 19 is provided on one side of the slide rail 21. A slider on the rear side of the clamping cylinder 19 is slidably connected to the slide rail 21, and a grabbing clamp 20 is fixedly connected to the bottom of the clamping cylinder 19.

[0028] When loading, the clamping cylinder 19 slides on the slide rail 21 through the slider, controls the position of the gripper 20, clamps the nut, and places the nut into the placement cavity inside the placement block 23. After the placement is completed, the rotating motor 3 drives the turntable 4 to rotate, and switches the nut to the bottom of the tap 11. The turntable 4 can carry multiple nuts for loading, tapping and unloading in turn, which improves the utilization rate of the equipment and is suitable for large-scale production needs.

[0029] like Figure 6-Figure 8 As shown, a plurality of fixed plates 22 are provided above the turntable 4, and a placement block 23 is provided above each of the fixed plates 22. A material unloading assembly is provided inside each of the placement blocks 23. The material unloading assembly is provided in a plurality of groups, and each group of material unloading assemblies includes a material unloading cylinder 24. The material unloading cylinder 24 is located on one side of the placement block 23, and a placement cavity is provided inside the placement block 23. A push plate 25 is slidably connected inside the placement cavity. The output end of the material unloading cylinder 24 is fixedly connected to the push plate 25, and a flexible block 26 is fixedly connected to the front side of the push plate 25. Push rods 34 are fixedly connected on both sides of the push plate 25. The front ends of the two push rods 34 are fixedly connected to connecting plates 28. An inclined groove is provided inside the two connecting plates 28, and a sliding rod 29 is slidably connected inside the two inclined grooves. A sliding groove is provided inside the placement block 23, and a limit block 30 is slidably connected inside the sliding groove. The two ends of the limit block 30 are respectively fixedly connected to the corresponding sliding rod 29, and a baffle 27 is connected above the limit block 30.

[0030] When the tapping is completed, the turntable 4 rotates, driving the nut after the tapping is completed to rotate to the side away from the gripper 20, and the push plate 25 is driven to move forward through the unloading cylinder 24. When the push plate 25 moves forward, the flexible block 26 contracts. At this time, the push plate 25 drives the push rod 34 to move forward. When the push rod 34 moves forward, it drives the connecting plate 28 to slide forward, and then drives the slide bar 29 to move downward in the inclined groove of the connecting plate 28. Because the limit block 30 at the bottom of the baffle 27 moves with the slide groove inside the placement block 23, and because the slide bar 29 is connected to the limit block 30, when the slide bar 29 moves downward, it drives the baffle 27 to move downward. At this time, the nut in the placement cavity can be pushed out to the external collection box.

[0031] The flexible block 26 provides a retractable distance so that when the push plate 25 is pushed, the nut does not move outward immediately, and the baffle 27 can move downward first, preventing the nut from moving when the baffle 27 has not fully opened the feed opening, thereby preventing the nut from interfering with the feed opening that has not been fully opened, reducing feed failures.

[0032] After unloading is completed, the unloading cylinder 24 drives the push plate 25 to move backward, thereby causing the baffle 27 to rise again. The rising baffle 27 can close the placement cavity, prepare for the next loading and processing, and improve the continuity and efficiency of production.

[0033] Working principle: First, the clamping cylinder 19 slides on the slide rail 21 through the slider, controls the gripper 20 to clamp the nut and place it in the placement cavity of the placement block 23 on the turntable 4, and then the rotating motor 3 drives the turntable 4 to rotate, and switches the nut to the bottom of the tap 11. At this time, the tapping motor 7 drives the rotating rod 13 to rotate. Because the internal spline of the sleeve 15 is spline-connected with the spline shaft 31 on the connecting rod 10 and the rotating rod 13, the tapping motor 7 drives the tap 11 under the connecting rod 10 to rotate forward through the rotating rod 13 when it is running, and the nut is tapped. At this time The second transmission gear 17 above the rotating rod 13 drives the second transmission gear 17 on the transmission rod 12 to rotate, and the transmission rod 12 drives the first transmission gear 16 to rotate, and then drives the output gear 32 to rotate through the idler gear 14. Because the output gear 32 is not in contact with the connecting rod 10 at this time, the output gear 32 is in an idling state. When the wire is withdrawn, the reversing cylinder 8 drives the reversing block 9 to move downward, and the inner spline of the sleeve 15 is disengaged from the spline shaft 31 on the rotating rod 13. At this time, the outer spline of the sleeve 15 forms a spline connection with the spline hole of the output gear 32, and the tapping motor When the power of the forward rotation is transmitted to the output gear 32, because the outer spline of the sleeve 15 is connected with the spline of the output gear 32, and because of the existence of the idler gear 14, the rotation of the output gear 32 will drive the connecting rod 10 to rotate in the opposite direction to realize the withdrawal of the nut. After the withdrawal is completed, the turntable 4 rotates to turn the nut to the side away from the gripper 20, the unloading cylinder 24 drives the push plate 25 to move, and the flexible block 26 contracts. At this time, the push plate 25 drives the push rod 34 to move forward. When the push rod 34 moves forward, it drives the connecting plate 28 to slide forward, and then drives the slide bar 29 to move in the connecting The plate 28 moves downward in the inclined groove, because the limit block 30 at the bottom of the baffle 27 moves with the slide groove inside the placement block 23, and because the slide bar 29 is connected to the limit block 30, when the slide bar 29 moves downward, it drives the baffle 27 to move downward. At this time, the nut in the placement cavity can be pushed out to the external collection box. After unloading is completed, the unloading cylinder 24 drives the push plate 25 to move backward, so that the baffle 27 rises again. The rising baffle 27 can close the placement cavity, prepare for the next loading and processing, and improve the continuity and efficiency of production.

[0034] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0035] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A nut tapping device, characterized in that: include: A workbench (1), wherein a hydraulic rod (5) is installed on the top of the workbench (1), a connecting block (6) is provided on the top of the hydraulic rod (5), and a reversing assembly is provided inside the connecting block (6); The reversing assembly comprises a driving component and a reversing component, the driving component comprises a reversing cylinder (8), the reversing cylinder (8) is located on one side of the connecting block (6), the output end of the reversing cylinder (8) is fixedly connected to a reversing block (9), one end of the connecting block (6) is provided with a slide groove, the reversing block (9) is slidably connected to the slide groove, one end of the reversing block (9) extends through the interior of the connecting block (6) and is connected to a bearing (33), the reversing block (9) is used to drive the reversing component to perform reversing; The reversing component comprises a connecting rod (10), a transmission rod (12) and a rotating rod (13); the connecting rod (10), the transmission rod (12) and the rotating rod (13) are all rotatably connected to the connecting block (6); the rotating rod (13) and the connecting rod (10) are fixedly connected to a spline shaft (31) at one end thereof that is close to each other; sleeves (15) are provided outside the two spline shafts (31); and the bearing (33) is connected to one end of the sleeve (15).

2. A nut tapping device according to claim 1, characterized in that: The reversing component further comprises an output gear (32), a plurality of support rods (18) being fixedly connected to the bottom of the output gear (32), an annular groove being provided inside the connecting block (6), the plurality of support rods (18) being slidably connected to the annular groove, and the output gear (32) being located outside the connecting rod (10) and not in contact with the connecting rod (10).

3. A nut tapping device according to claim 2, characterized in that: Both ends of the sleeve (15) are provided with external splines and internal splines, a spline hole is provided on the inner side of the output gear (32), the internal splines on the sleeve (15) are respectively spline-connected with the two spline shafts (31), and the external splines of the sleeve (15) are spline-connected with the spline hole on the inner side of the output gear (32).

4. A nut tapping device according to claim 2, characterized in that: An idler wheel (14) is rotatably connected inside the connection block (6); one end of the transmission rod (12) and the rotating rod (13) are both fixedly connected to a second transmission gear (17); the two second transmission gears (17) are meshed with each other; one end of the transmission rod (12) away from the second transmission gear (17) is fixedly connected to a first transmission gear (16); and two ends of the idler wheel (14) are respectively meshed with the output gear (32) and the first transmission gear (16).

5. A nut tapping device according to claim 1, characterized in that: A tapping motor (7) is provided on the top of the connection block (6), the output end of the tapping motor (7) is fixedly connected to a rotating rod (13), and one end of the connection rod (10) extends through and to the outside of the connection block (6) and is fixedly connected to a tap (11).

6. A nut tapping device according to claim 1, characterized in that: A frame (2) is provided on the top of the workbench (1), a turntable (4) is rotatably connected to the top of the frame (2), a rotary motor (3) is provided on the bottom of the frame (2), and an output end of the rotary motor (3) is fixedly connected to a shaft inside the turntable (4).

7. A nut tapping device according to claim 6, characterized in that: A plate body is provided at one end of the workbench (1) close to the turntable (4), a slide rail (21) is provided on one side of the plate body, a clamping cylinder (19) is provided on one side of the slide rail (21), a slider at the rear side of the clamping cylinder (19) is slidably connected to the slide rail (21), and a gripping clamp (20) is fixedly connected to the bottom of the clamping cylinder (19).

8. A nut tapping device according to claim 6, characterized in that: A plurality of fixing plates (22) are provided above the rotating disk (4), a placement block (23) is provided above each of the plurality of fixing plates (22), and a material discharge assembly is provided inside each of the plurality of placement blocks (23).

9. A nut tapping device according to claim 8, characterized in that: The material unloading assembly is provided with a plurality of groups, each group of the material unloading assembly comprises a material unloading cylinder (24), the material unloading cylinder (24) being located at one side of a placing block (23), a placing cavity being provided inside the placing block (23), a push plate (25) being slidably connected inside the placing cavity, an output end of the material unloading cylinder (24) being fixedly connected to the push plate (25), a flexible block (26) being fixedly connected to the front side of the push plate (25), push rods (34) being fixedly connected to both sides of the push plate (25), front ends of two push rods (34) being fixedly connected to connecting plates (28), oblique grooves being provided inside the two connecting plates (28), slide rods (29) being slidably connected inside the two oblique grooves, a slide groove being provided inside the placing block (23), a limit block (30) being slidably connected inside the slide groove, two ends of the limit block (30) being fixedly connected to corresponding slide rods (29), a baffle (27) being connected above the limit block (30).

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