Automatic feeding and discharging device of turning-milling composite numerical control lathe robot

Abstract

The invention belongs to the technical field of numerical control lathes, and particularly relates to a robot automatic feeding and discharging device for a turn-milling composite numerical control lathe, which comprises a base and a lathe, the lathe is fixedly connected to the top of the base, a track frame is fixedly connected to the top of the base, a track is fixedly connected to one side of the track frame, and the track of the track is arc-shaped. The top of the rail is slidably connected with an electric sliding rail. According to the automatic feeding and discharging device, the weighing goods shelf achieves real-time monitoring of the machining process, the overall automation degree of the device is greatly improved through cooperation with the robot, the feeding and discharging efficiency is improved, faster machining circulation is achieved, the first motor is started only when the robot is located at the position farthest from the lathe, collision between the robot and the lathe is avoided, and the machining efficiency is improved. Safety accidents in production are avoided, the whole production process is coherent and smooth due to the cooperative design of a plurality of action parts, the waiting time between the working procedures is shortened, and the production rhythm is further improved.

Description

Technical Field

[0001] The present invention relates to the technical field of CNC lathes, and in particular to an automatic loading and unloading device for a CNC lathe robot for turning and milling compound CNC lathes. Background Technology

[0002] In modern manufacturing, milling and turning composite processing technology is widely used due to its high precision and high efficiency. The loading and unloading robots of existing milling and turning CNC lathes cannot accurately determine whether all tasks have been completed, which can easily lead to inaccurate monitoring of the processing process and affect production efficiency. In addition, the traditional structure lacks an automated connection design during the device reset process, which affects the continuity and automation of production.

[0003] After searching, the Chinese patent application with application publication number CN117733626A discloses an automatic loading and unloading device for a milling compound CNC lathe robot, including an adjustment component, which can clamp the workpiece to be processed through a manipulator, insert the workpiece into the fixed chuck of the milling compound CNC lathe, so as to realize automatic loading of the workpiece, and unload the workpiece by setting the adjustment component, the unloading component and the unloading component.

[0004] The above device has obvious limitations in the process connection and automation of loading and unloading. It is necessary to improve and innovate the existing automatic loading and unloading device of the turning and milling compound CNC lathe robot. SUMMARY OF THE INVENTION

[0005] Based on the technical problems of insufficient process connection and automation of loading and unloading, the present invention proposes an automatic loading and unloading device for a turning and milling compound CNC lathe robot.

[0006] The present invention proposes an automatic loading and unloading device for a turning and milling composite CNC lathe robot, comprising a base and a lathe, wherein the lathe is fixedly connected to the top of the base, the top of the base is fixedly connected to a track frame, one side of the track frame is fixedly connected to a track, the track of the track is in an arc shape, the top of the track is slidably connected to an electric slide rail, two connecting frames are fixedly connected to the end of the electric slide rail away from the lathe, the ends of the two connecting frames away from the electric slide rail are fixedly connected to the same transmission rack, the transmission rack is arranged to be in an arc shape coinciding with the track center of the track, the top of the base is rotatably connected to a gear plate meshing with the transmission rack, the top of the base is fixedly connected to a motor frame, the inside of the motor frame is fixedly connected to a first motor, the gear plate is transmission-connected to the output end of the first motor, the end of the electric slide rail away from the lathe is fixedly connected to a travel switch, the top of the electric slide rail is slidably connected to a sliding bracket, the top of the sliding bracket is fixedly connected to a mounting platform, the top of the mounting platform is fixedly connected to a robot, and two weighing shelves are arranged on the side of the base close to the electric slide rail.

[0007] Preferably, the lathe is slidably connected to one side of the lathe close to the electric slide rail with two symmetrically arranged electric doors, the interior of the lathe is provided with a turning and milling tool, and the outer wall of the lathe close to the electric slide rail is provided with a touch screen.

[0008] Preferably, the bottom of the electric slide rail is symmetrically provided with two ball grooves, the interiors of the two ball grooves are filled with balls that can roll freely, and the top surface of the base and the top inner wall of the ball groove are in contact with the two sides of the balls respectively.

[0009] Preferably, a fixing rod is fixedly connected to the top of the base, a baffle is fixedly connected to the top of the fixing rod, two mounting grooves are symmetrically provided on one side of the baffle close to the electric slide rail, and pressure sensors are fixedly connected inside the two mounting grooves.

[0010] Preferably, two sliding sleeves are fixedly connected to the top of the base, a synchronous connecting rod is fixedly connected between the two sliding sleeves, sliding bars are slidably connected inside the two sliding sleeves, a collision plate is fixedly connected to one end of the two sliding bars close to the electric slide rail, a pressing plate is fixedly connected to one end of the two sliding bars close to the baffle, and two contacts are fixedly connected to one side of the pressing plate close to the baffle, and the two contacts are respectively adapted to two pressure sensors.

[0011] Preferably, the synchronous connecting rod and the pressing plate are fixedly connected with a same spring.

[0012] Preferably, a second motor is fixedly connected inside the motor frame, and a bidirectional screw is transmission-connected to the output end of the second motor. Both ends of the bidirectional screw are threadedly connected to clamping frames. The two clamping frames are symmetrically arranged, and both clamping frames are slidably connected to the motor frame in the vertical direction. Cleaning brushes are fixedly connected to the adjacent sides of the two clamping frames, and the two cleaning brushes are respectively located on both sides of the transmission rack.

[0013] Preferably, the top of the upper clamping frame is fixedly connected with an oil tank, the bottom of the oil tank is provided with evenly distributed oil holes, and the bottom of the oil holes is connected to the top of the cleaning brush.

[0014] Preferably, the base is fixedly connected to one side close to the weighing shelf with two parallel guide rods, the rod bodies of the two guide rods are slidably connected to sliding seats, the two weighing shelves are respectively fixedly connected to the tops of the two sliding seats, and the ends of the two guide rods away from the base are plugged with latches.

[0015] Preferably, the bottoms of the two sliding seats are symmetrically provided with roller grooves, and the inner walls at both ends of the roller grooves are rotatably connected with rollers.

[0016] Compared with the prior art, the present invention provides an automatic loading and unloading device for a turning and milling compound CNC lathe robot, which has the following beneficial effects: 1. This kind of automatic loading and unloading device for a turning and milling compound CNC lathe robot is equipped with a weighing shelf, a robot, an electric slide rail, a travel switch, a first motor and a transmission rack. The weighing shelf realizes real-time monitoring of the processing process. The robot greatly improves the overall automation of the device, improves the efficiency of loading and unloading, and realizes faster processing flow. The first motor will only start when the robot is farthest from the lathe, avoiding collisions between the robot and the lathe, and avoiding safety accidents in production. The coordinated design of multiple action parts makes the entire production process coherent and smooth, reduces the waiting time between each process, and further improves the production rhythm.

[0017] 2. This automatic loading and unloading device for a milling compound CNC lathe robot is equipped with an impact plate, a pressing plate, a contact point and a pressure sensor. Before starting the next processing program, when the electric slide rail needs to be reset, the material is stacked on the weighing shelf where the material to be processed is placed. After the weighing shelf detects the weight change, it will control the first motor to reverse through an electrical signal, and then drive the electric slide rail to return to the loading and unloading station through the gear plate and the transmission rack. When the electric slide rail reaches the specified position, one side of the electric slide rail contacts the impact plate. After the impact plate is subjected to force, it moves toward the baffle together with the sliding bar and the pressing plate, so that the pressure sensor is subjected to pressure from the contact point. The electrical signal generated in this process controls the first motor to stop driving, thereby realizing the automatic connection between the two processing procedures.

[0018] 3. The automatic loading and unloading device of the turning and milling compound CNC lathe robot is provided with a second motor, a bidirectional screw, a clamping frame, a cleaning brush and an oil tank. The bidirectional screw can be driven to rotate by the second motor, and then the two clamping frames are driven to approach the transmission rack at the same time, so that the two cleaning brushes contact the upper and lower sides of the transmission rack respectively. When the first motor drives the transmission rack, the transmission rack moves relative to the cleaning brush, and the automatic cleaning of the transmission rack can be realized. When the transmission rack needs to be lubricated and maintained, the transmission rack is first preliminarily cleaned through the above steps, and then lubricating oil is poured into the oil tank. The lubricating oil is supplied to the cleaning brush through the oil hole to fully soak the bristles. At this time, the transmission rack is driven again by the first motor to make the transmission rack move relative to the cleaning brush, so that the lubricating oil on the bristles is evenly attached to the surface of the transmission rack to form a stable lubricating oil film, thereby providing lasting lubrication protection for the transmission rack, reducing wear and extending the service life. Brief Description of the Figures

[0019] Figure 1 This is a structural schematic diagram of an automatic loading and unloading device for a turning and milling compound CNC lathe robot proposed by the present invention; Figure 2 It is a top view structural schematic diagram of an automatic loading and unloading device for a turning-milling compound CNC lathe robot proposed by the present invention; Figure 3 This is a partial structural schematic diagram of an automatic loading and unloading device for a turning-milling compound CNC lathe robot proposed by the present invention; Figure 4 This is a schematic diagram of the impact plate, pressing plate and baffle structure of the automatic loading and unloading device of the turning and milling compound CNC lathe robot proposed by the present invention; Figure 5 This is a schematic diagram of the bottom structure of an electric slide rail of an automatic loading and unloading device of a turning and milling compound CNC lathe robot proposed by the present invention; Figure 6 This is a left-side structural schematic diagram of an automatic loading and unloading device for a turning-milling compound CNC lathe robot proposed by the present invention; Figure 7 This is a schematic diagram of the structure of the motor frame, the second motor and the clamping frame of the automatic loading and unloading device of the turning and milling compound CNC lathe robot proposed by the present invention; Figure 8 This is a structural schematic diagram of another perspective of the automatic loading and unloading device of a turning-milling compound CNC lathe robot proposed by the present invention; Figure 9 For Figure 8 The enlarged schematic diagram of point A in the middle.

[0020] In the figure: 1. Base; 2. Lathe; 3. Electric door; 4. Touch screen; 5. Milling tool; 6. Track frame; 7. Track; 8. Electric slide rail; 9. Travel switch; 10. Connecting frame; 11. Sliding bracket; 12. Mounting platform; 13. Robot; 14. Sliding seat; 15. Weighing shelf; 16. Transmission rack; 17. Motor frame; 18. First motor; 19. Second motor; 20. Clamping frame; 2 1. Gear plate; 22. Fixed rod; 23. Baffle; 24. Sliding bar; 25. Sliding sleeve; 26. Synchronous connecting rod; 27. Impact plate; 28. Spring; 29. ​​Contact; 30. Mounting slot; 31. Pressure sensor; 32. Press plate; 33. Ball groove; 34. Ball; 35. Bidirectional screw; 36. Oil groove; 37. Cleaning brush; 38. Oil hole; 39. Roller; 40. Roller groove; 41. Latch; 42. Guide rod. Specific implementation method

[0021] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them.

[0022] Reference Figures 1-9A turning and milling compound CNC lathe robot automatic loading and unloading device comprises a base 1 and a lathe 2, the lathe 2 is fixedly connected to the top of the base 1, the top of the base 1 is fixedly connected to a track frame 6, one side of the track frame 6 is fixedly connected to a track 7, the track of the track 7 is an arc shape, the top of the track 7 is slidably connected to an electric slide rail 8, the electric slide rail 8 can slide along the track of the track 7 under the drive of an external force, during the sliding process, the electric slide rail 8 always keeps in contact with the track 7, and the movement direction is always along the tangent direction of the track 7, two connecting frames 10 are fixed to the end of the electric slide rail 8 away from the lathe 2, and the ends of the two connecting frames 10 away from the electric slide rail 8 are fixedly connected to the same transmission rack 16, the transmission rack 16 is set to be an arc shape that coincides with the center of the trajectory of the track 7, the top of the base 1 is rotatably connected to a gear plate 21 that meshes with the transmission rack 16, the top of the base 1 is fixedly connected to a motor frame 17, the inside of the motor frame 17 is fixedly connected to a first motor 18, the gear plate 21 is transmission-connected to the output end of the first motor 18, the end of the electric slide 8 away from the lathe 2 is fixedly connected to a travel switch 9, the top of the electric slide 8 is slidably connected to a sliding bracket 11, the top of the sliding bracket 11 is fixedly connected to a mounting platform 12, the top of the mounting platform 12 is fixedly connected to a robot 13, and two weighing shelves 15 are arranged on the side of the base 1 close to the electric slide 8.

[0023] In the present invention, two symmetrically arranged electric doors 3 are slidably connected to one side of the lathe 2 close to the electric slide rail 8, a milling tool 5 is arranged inside the lathe 2, and a touch screen 4 is arranged on the outer wall of the lathe 2 close to the electric slide rail. When the robot 13 loads and unloads materials, the electric door 3 slides open to facilitate the robot 13 to enter and exit the lathe 2 for operation. The milling tool 5 is used to fix the materials, and the touch screen 4 is used to control the lathe 2.

[0024] In the present invention, two ball grooves 33 are symmetrically formed at the bottom of the electric slide rail 8, and the interiors of the two ball grooves 33 are filled with balls 34 that can roll freely. The top surface of the base 1 and the top inner wall of the ball groove 33 are in contact with the two sides of the balls 34 respectively. The balls 34 replace the direct contact between the electric slide rail 8 and the base 1, thereby reducing the resistance of the electric slide rail 8 during movement and reducing the loss of the device.

[0025] In the present invention, a fixing rod 22 is fixedly connected to the top of the base 1, a baffle 23 is fixedly connected to the top of the fixing rod 22, two mounting grooves 30 are symmetrically opened on one side of the baffle 23 close to the electric slide rail 8, and pressure sensors 31 are fixedly connected inside the two mounting grooves 30.

[0026] In the present invention, two sliding sleeves 25 are fixedly connected to the top of the base 1, and a synchronous connecting rod 26 is fixedly connected between the two sliding sleeves 25. The insides of the two sliding sleeves 25 are slidably connected with sliding bars 24. The ends of the two sliding bars 24 close to the electric slide rail 8 are fixedly connected to the same impact plate 27. The ends of the two sliding bars 24 close to the baffle 23 are fixedly connected to the same pressing plate 32. The side of the pressing plate 32 close to the baffle 23 is fixedly connected to two contacts 29. The two contacts 29 are respectively adapted to two pressure sensors 31. Before starting the next processing program, when the electric slide rail 8 needs to be reset, the object The materials are stacked on the weighing shelf 15 where the materials to be processed are placed. After the weighing shelf 15 detects the weight change, it will control the first motor 18 to reverse through an electrical signal, and then drive the electric slide 8 to return to the loading and unloading station through the gear plate 21 and the transmission rack 16. When the electric slide 8 reaches the specified position, one side of the electric slide 8 contacts the impact plate 27. After the impact plate 27 is subjected to force, it moves toward the baffle 23 together with the sliding bar 24 and the pressing plate 32, so that the pressure sensor 31 is subjected to pressure from the contact 29. The electrical signal generated in this process controls the first motor 18 to stop driving, realizing the automatic connection between the two processing steps.

[0027] In the present invention, a spring 28 is fixedly connected between the synchronous link 26 and the pressing plate 32. After the electric slide rail 8 pushes the impact plate 27, the spring 28 is stretched. When the electric slide rail 8 moves away from the impact plate 27 again, the spring 28 can drive the impact plate 27 and the contact 29 to reset.

[0028] In the present invention, the motor frame 17 is fixedly connected to the inside with a second motor 19, and the output end of the second motor 19 is transmission-connected with a bidirectional screw 35, and both ends of the bidirectional screw 35 are threadedly connected with a clamping frame 20, and the two clamping frames 20 are symmetrically arranged, and the two clamping frames 20 are slidably connected to the motor frame 17 in the vertical direction, and the two clamping frames 20 are fixedly connected to the side close to each other with a cleaning brush 37, and the two cleaning brushes 37 are respectively located on both sides of the transmission rack 16, and the bidirectional screw 35 can be driven to rotate by the second motor 19, thereby driving the two clamping frames 20 to approach the transmission rack 16 at the same time, so that the two cleaning brushes 37 contact the upper and lower sides of the transmission rack 16 respectively, and when the first motor 18 drives the transmission rack 16, the transmission rack 16 moves relative to the cleaning brush 37, and the automatic cleaning of the transmission rack 16 can be realized.

[0029] In the present invention, the top of the clamping frame 20 located above is fixedly connected with an oil groove 36, and the bottom of the oil groove 36 is provided with evenly distributed oil holes 38. The bottom of the oil hole 38 is connected to the top of the cleaning brush 37. When the transmission rack 16 needs to be lubricated and maintained, the transmission rack 16 is firstly cleaned, and then lubricating oil is poured into the oil groove 36. The lubricating oil is supplied to the cleaning brush 37 through the oil hole 38 to fully soak the bristles. At this time, the transmission rack 16 is driven again by the first motor 18 to make the transmission rack 16 move relative to the cleaning brush 37, so that the lubricating oil on the bristles is evenly attached to the surface of the transmission rack 16 to form a stable lubricating oil film, thereby providing lasting lubrication protection for the transmission rack 16, reducing wear and extending the service life.

[0030] In the present invention, two parallel guide rods 42 are fixedly connected to one side of the base 1 close to the weighing shelf 15, and the rod bodies of the two guide rods 42 are slidably connected to the sliding seat 14. The two weighing shelves 15 are respectively fixedly connected to the tops of the two sliding seats 14. The ends of the two guide rods 42 away from the base 1 are plugged with latches 41. The weighing shelf 15 is fixed on the sliding seat 14, and the sliding seat 14 is positioned by the guide rods 42. After the latch 41 is inserted into the guide rods 42, the position of the sliding seat 14 can be locked.

[0031] In the present invention, roller grooves 40 are symmetrically opened at the bottom of the two sliding seats 14, and rollers 39 are rotatably connected to the inner walls of the two ends of the roller grooves 40. After the latch 41 is pulled out, the sliding seat 14 can be moved along the guide rod 42, and then the weighing shelf 15 can be separated from one side of the base 1. The setting of the rollers 39 makes the movement process of the sliding seat 14 more labor-saving, which is convenient for maintenance and debugging of the weighing shelf 15.

[0032] When in use, the two weighing shelves 15 can detect the weight of the materials stacked on their tops, and are used to stack the materials to be processed and the processed materials respectively. The robot 13 is fixedly installed on the mounting platform 12. After reaching the designated position driven by the electric slide rail 8, it performs automatic loading and unloading operations, that is, taking the materials from the weighing shelf 15 where the materials to be processed are placed, and placing the processed materials on the other weighing shelf 15. When the weighing shelf 15 where the materials to be processed are placed detects that there is no material on the top, and the other weighing shelf 15 detects that the materials are full, it means that the surface has completed the turning and milling of all the workpieces. At this time, the electric The movable slide 8 drives the sliding bracket 11 to slide away from the lathe 2 until the sliding bracket 11 triggers the travel switch 9. At this time, the robot 13, the sliding bracket 11 and the mounting platform 12 are located on the electric slide 8 at the position farthest from the lathe. After the first motor 18 detects the electrical signal of the travel switch 9, it drives the gear plate 21 to rotate, drives the transmission rack 16, and drives the electric slide 8 to move along the track 7, so that the electric slide 8 together with the sliding bracket 11, the mounting platform 12 and the robot 13 on its top move to one side of the lathe, away from the loading and unloading station, so that the staff can perform other operations on the lathe.

[0033] The above is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field within the technical scope disclosed by the present invention can make equivalent replacements or changes based on the technical solution and inventive concept of the present invention, which should be covered by the protection scope of the present invention.

Claims

1. An automatic loading and unloading device for a turning and milling composite CNC lathe robot, comprising a base (1) and a lathe (2), wherein the lathe (2) is fixedly connected to the top of the base (1), and is characterized in that: The top of the base (1) is fixedly connected to a track frame (6), one side of the track frame (6) is fixedly connected to a track (7), the track of the track (7) is in an arc shape, the top of the track (7) is slidably connected to an electric slide rail (8), two connecting frames (10) are fixed to one end of the electric slide rail (8) away from the lathe (2), the two connecting frames (10) are fixedly connected to the same transmission rack (16) at one end away from the electric slide rail (8), the transmission rack (16) is arranged in an arc shape that coincides with the center of the track of the track (7), and the top of the base (1) is rotatably connected to a gear plate (21) meshing with the transmission rack (16). The top of the base (1) is fixedly connected to a motor frame (17), the interior of the motor frame (17) is fixedly connected to a first motor (18), a gear plate (21) is drivingly connected to an output end of the first motor (18), an end of the electric slide rail (8) away from the lathe (2) is fixedly connected to a travel switch (9), the top of the electric slide rail (8) is slidably connected to a sliding bracket (11), the top of the sliding bracket (11) is fixedly connected to a mounting platform (12), the top of the mounting platform (12) is fixedly connected to a robot (13), and two weighing shelves (15) are arranged on one side of the base (1) close to the electric slide rail (8).

2. The automatic loading and unloading device of a turning-milling compound CNC lathe robot according to claim 1 is characterized in that: The lathe (2) is slidably connected to one side of the lathe (2) close to the electric slide rail (8) with two symmetrically arranged electric doors (3), a turning and milling tool (5) is arranged inside the lathe (2), and a touch screen (4) is arranged on the outer wall of the lathe (2) close to the electric slide rail.

3. The automatic loading and unloading device of a turning-milling compound CNC lathe robot according to claim 1 is characterized in that: Two ball grooves (33) are symmetrically formed at the bottom of the electric slide rail (8), and the interiors of the two ball grooves (33) are filled with balls (34) that can roll freely, and the top surface of the base (1) and the top inner walls of the ball grooves (33) are in contact with two sides of the balls (34) respectively.

4. The automatic loading and unloading device for a turning-milling compound CNC lathe robot according to claim 1 is characterized in that: A fixing rod (22) is fixedly connected to the top of the base (1), a baffle (23) is fixedly connected to the top of the fixing rod (22), two mounting grooves (30) are symmetrically provided on one side of the baffle (23) close to the electric slide rail (8), and pressure sensors (31) are fixedly connected inside the two mounting grooves (30).

5. The automatic loading and unloading device of a turning-milling compound CNC lathe robot according to claim 4 is characterized in that: Two sliding sleeves (25) are fixedly connected to the top of the base (1); a synchronous connecting rod (26) is fixedly connected between the two sliding sleeves (25); sliding bars (24) are slidably connected inside the two sliding sleeves (25); a same impact plate (27) is fixedly connected to one end of the two sliding bars (24) close to the electric slide rail (8); a same pressing plate (32) is fixedly connected to one end of the two sliding bars (24) close to the baffle (23); two contacts (29) are fixedly connected to one side of the pressing plate (32) close to the baffle (23); and the two contacts (29) are respectively adapted to two pressure sensors (31).

6. The automatic loading and unloading device for a turning-milling compound CNC lathe robot according to claim 5 is characterized in that: A common spring (28) is fixedly connected between the synchronous connecting rod (26) and the pressing plate (32).

7. The automatic loading and unloading device for a turning-milling compound CNC lathe robot according to claim 1 is characterized in that: A second motor (19) is fixedly connected inside the motor frame (17), and a bidirectional screw (35) is drivingly connected to the output end of the second motor (19). Both ends of the bidirectional screw (35) are threadedly connected to a clamping frame (20). The two clamping frames (20) are symmetrically arranged, and the two clamping frames (20) are slidably connected to the motor frame (17) in the vertical direction. Cleaning brushes (37) are fixedly connected to the adjacent sides of the two clamping frames (20), and the two cleaning brushes (37) are respectively located on both sides of the transmission rack (16).

8. The automatic loading and unloading device for a turning-milling compound CNC lathe robot according to claim 7 is characterized in that: The top of the upper clamping frame (20) is fixedly connected to an oil groove (36), the bottom of the oil groove (36) is provided with evenly distributed oil holes (38), and the bottom of the oil holes (38) is connected to the top of the cleaning brush (37).

9. The automatic loading and unloading device of a turning-milling compound CNC lathe robot according to claim 1 is characterized in that: Two parallel guide rods (42) are fixedly connected to one side of the base (1) close to the weighing shelf (15); the rod bodies of the two guide rods (42) are slidably connected to the sliding seats (14); the two weighing shelves (15) are respectively fixedly connected to the tops of the two sliding seats (14); and the ends of the two guide rods (42) away from the base (1) are plugged with latches (41).

10. The automatic loading and unloading device of a turning-milling compound CNC lathe robot according to claim 9 is characterized in that: The bottoms of the two sliding seats (14) are symmetrically provided with roller grooves (40), and the inner walls at both ends of the roller grooves (40) are rotatably connected to rollers (39).

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