Corner grinding device for new energy automobile thermal management profile

Abstract

The utility model discloses a new energy automobile thermal management profile corner polishing device, which relates to the technical field of polishing devices and comprises a polishing box, a protective support is fixedly mounted on the inner side wall of the polishing box, an adjusting mechanism is arranged at one end of the polishing box, and a polishing mechanism is arranged at the upper end of the adjusting mechanism. A fixing mechanism is arranged at the upper end of the grinding box; and the adjusting mechanism comprises a fixed plate, a front-back adjusting structure and an up-down adjusting structure, a movable plate is fixedly installed on a movable part on one side of the up-down adjusting structure, and a supporting frame is fixedly installed at one end of the movable plate. According to the profile polishing device, the polishing wheel can be moved to the proper position of the corner of the profile, so that the corners of the profiles in different special shapes can be completely polished, the polishing effect is ideal, meanwhile, the surface of the profile cannot be scratched in the polishing process, and the integrity of the profile cannot be influenced.

Description

Technical Field

[0001] The utility model relates to the technical field of grinding devices, and in particular to an edge and corner grinding device for thermal management profiles of new energy vehicles. Background Art

[0002] New energy vehicle thermal management profiles generally refer to various aluminum alloy profiles used in new energy vehicle thermal management systems. In the thermal management of new energy vehicles, the role of profiles is to help effectively transfer and dissipate heat to ensure that all parts of the vehicle work within a suitable temperature range. In short, automotive thermal management profiles play an important role in automotive thermal management systems, and with the continuous development of the new energy vehicle market, their demand is also growing continuously. In order to finely process the edges and corners of this type of profile to improve its surface quality and dimensional accuracy, an edge grinding device is required.

[0003] However, in the prior art, when grinding the edges and corners of some profiles with particularly complex shapes, due to the special shapes of the profile edges and corners, the profile edges and corners cannot be completely ground, resulting in an unsatisfactory grinding effect, and the surface of the profile will be scratched during the grinding process, thereby affecting the integrity of the profile. Therefore, a device for grinding edges and corners of thermal management profiles for new energy vehicles is proposed. Utility Model Content

[0004] The purpose of the utility model is to solve the problem in the prior art that due to the special shape of the profile corners, the profile corners cannot be completely polished, resulting in an unsatisfactory polishing effect, and the surface of the profile is scratched during the polishing process, thereby affecting the integrity of the profile. A device for polishing the corners of the thermal management profile of a new energy vehicle is proposed.

[0005] In order to achieve the above-mentioned purpose, the utility model adopts the following technical scheme: a corner grinding device for thermal management profiles of new energy vehicles, comprising a grinding box, a protective support is fixedly installed on the inner side wall of the grinding box, an adjustment mechanism is arranged at one end of the grinding box, a grinding mechanism is arranged at the upper end of the adjustment mechanism, and a fixing mechanism is arranged at the upper end of the grinding box;

[0006] The adjusting mechanism comprises a fixed plate, a front and rear adjusting structure and an up and down adjusting structure, a movable part on one side of the up and down adjusting structure is fixedly installed with a movable plate, one end of the movable plate is fixedly installed with a supporting frame, one end of the fixed plate is fixedly installed with a servo motor, the movable part at the upper end of the front and rear adjusting structure is fixedly installed with a fixed frame seat, the output end of the servo motor is fixedly installed with a rotating rod, the outer wall of the rotating rod and the first synchronous wheel are fixedly installed at the edge position, the outer wall of the rotating rod is fixedly installed with a second synchronous wheel, the outer wall of the first synchronous wheel is sleeved with a first synchronous belt, the upper end of the fixed frame seat is slidably installed with a movable frame plate, the lower end of the movable frame plate is fixedly installed with a threaded seat, one end of the fixed plate is rotatably installed with a screw, the outer wall of the screw is fixedly installed with a third synchronous wheel, and the outer wall of the second synchronous wheel is sleeved with a second synchronous belt;

[0007] The grinding mechanism includes a stable shaft seat, a transmission cylinder is rotatably mounted on one end of the fixed plate, a transmission rod is slidably clamped inside the transmission cylinder, a grinding wheel is fixedly mounted on the outer wall of the transmission rod, and a No. 4 synchronous wheel is fixedly mounted on the outer wall of the grinding wheel.

[0008] Preferably, the fixing mechanism includes a cylinder and a support block, a lower pressure plate is arranged above the support block, a vertical groove is opened at the upper end of the polishing box, a connecting frame plate is fixedly installed on the upper end of the lower pressure plate, and a long plate is slidably installed inside the vertical groove.

[0009] Preferably, the front-rear adjustment structure is fixedly installed inside the support frame, the moving part of the front-rear adjustment structure is fixed to the lower end of the fixed frame seat, and the outer frame of the upper and lower adjustment structure is fixed to the other end of the polishing box.

[0010] Preferably, a shielding shell is provided above the grinding wheel, one end of the shielding shell is fixed to one end of the stabilizing shaft seat, the transmission rod is rotatably mounted inside the stabilizing shaft seat, and the lower end of the stabilizing shaft seat is fixed to the upper end of the movable frame plate.

[0011] Preferably, one end of the cylinder is fixed to one end of the grinding box, the lower end of the support block is fixed to the upper end of the protective support, the protruding end of the cylinder is fixed to the lower end of the long board, and the upper end of the connecting frame plate is fixed to the lower end of the long board.

[0012] Preferably, a support frame is fixedly installed on the lower end of the polishing box, a protective shell is fixedly installed on the outer wall of the movable frame plate, and the transmission cylinder, transmission rod and stable shaft seat are all located inside the protective shell.

[0013] Preferably, the screw is threadedly connected to the inside of the threaded seat, the third synchronous wheel is driven by the second synchronous belt, and the first synchronous belt is driven by the fourth synchronous wheel.

[0014] Compared with the prior art, the advantages and positive effects of the utility model are:

[0015] 1. In the utility model, an adjustment mechanism and a grinding mechanism are provided, and the grinding wheel can be moved through the up and down adjustment structure and the front and back adjustment structure, and then the movable frame can be driven to move under the cooperation of the servo motor, the rotating rod, the second synchronous wheel, the second synchronous belt, the third synchronous wheel, the screw and the threaded seat, so that the movable frame can slide left and right on the fixed frame seat, and the fixed frame seat drives the grinding wheel to move through the stable shaft seat and the transmission rod, and can move the grinding wheel to the appropriate position of the edge corner of the profile, so that the edges and corners of profiles of different special shapes can be completely polished, so that the polishing effect meets the ideal, and at the same time, the surface of the profile will not be scratched during the grinding process, and the integrity of the profile will not be affected.

[0016] 2. In the utility model, a fixing mechanism is provided and the cylinder is started. The extended end of the cylinder drives the long plate to slide downward inside the vertical groove, and the long plate drives the lower pressure plate to move downward together through the connecting frame plate, so that the lower pressure plate moves toward the support block, and then the profile on the support block can be squeezed, so that the profile can be fixed on the support block to prevent the profile from moving during grinding. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The utility model provides a three-dimensional structural schematic diagram of a corner grinding device for thermal management profiles of new energy vehicles;

[0018] Figure 2 The utility model provides a schematic structural diagram of an adjusting mechanism and a grinding mechanism in a corner grinding device for thermal management profiles of new energy vehicles;

[0019] Figure 3 A partial stereoscopic diagram of an adjusting mechanism and a grinding mechanism in a corner grinding device for a thermal management profile of a new energy vehicle proposed in the utility model;

[0020] Figure 4 A three-dimensional diagram of a grinding box and a fixing mechanism in a corner grinding device for thermal management profiles of new energy vehicles proposed in the utility model;

[0021] Figure 5 The utility model provides a schematic planar structural diagram of a device for grinding corners of thermal management profiles for new energy vehicles.

[0022] Legend: 1. Grinding box; 11. Support frame; 12. Protective support; 13. Protective shell; 2. Adjustment mechanism; 21. Fixed plate; 22. Support frame; 23. Front and rear adjustment structure; 24. Up and down adjustment structure; 25. Movable plate; 26. Servo motor; 27. No. 1 synchronous wheel; 28. Movable frame plate; 29. ​​No. 1 synchronous belt; 210. Fixed frame seat; 211. Rotating rod; 212. No. 2 synchronous wheel; 213. Threaded seat; 214. Screw rod; 215. No. 3 synchronous wheel; 216. No. 2 synchronous belt; 3. Grinding mechanism; 30. Transmission cylinder; 31. Transmission rod; 32. Stable shaft seat; 33. Grinding wheel; 34. Shielding shell; 35. No. 4 synchronous wheel; 4. Fixing mechanism; 41. Cylinder; 42. Support block; 43. Lower pressure plate; 44. Vertical groove; 45. Connecting frame plate; 46. Long board. DETAILED DESCRIPTION

[0023] In order to more clearly understand the above-mentioned purpose, features and advantages of the utility model, the utility model is further described below in conjunction with the accompanying drawings and embodiments. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0024] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways than those described herein. Therefore, the present invention is not limited to the specific embodiments of the following disclosure.

[0025] Embodiment 1: Figure 1 As shown in FIG. 5 , the utility model provides an edge and corner grinding device for thermal management profiles of new energy vehicles, comprising a grinding box 1, a protective support 12 is fixedly installed on the inner side wall of the grinding box 1, an adjustment mechanism 2 is arranged at one end of the grinding box 1, a grinding mechanism 3 is arranged at the upper end of the adjustment mechanism 2, and a fixing mechanism 4 is arranged at the upper end of the grinding box 1;

[0026] The adjusting mechanism 2 includes a fixed plate 21, a front-rear adjusting structure 23 and an up-down adjusting structure 24, a movable plate 25 is fixedly installed on the movable part of one side of the up-down adjusting structure 24, a supporting frame 22 is fixedly installed on one end of the movable plate 25, a servo motor 26 is fixedly installed on one end of the fixed plate 21, a fixed frame seat 210 is fixedly installed on the movable part of the upper end of the front-rear adjusting structure 23, a rotating rod 211 is fixedly installed on the output end of the servo motor 26, a first synchronous wheel 27 is fixedly installed on the outer wall of the rotating rod 211 and located at the edge position, a second synchronous wheel 212 is fixedly installed on the outer wall of the rotating rod 211, a first synchronous belt 29 is sleeved on the outer wall of the first synchronous wheel 27, a movable frame plate 28 is slidably installed on the upper end of the fixed frame seat 210, a threaded seat 213 is fixedly installed on the lower end of the movable frame plate 28, a screw rod 214 is rotatably installed on one end of the fixed plate 21, a third synchronous wheel 215 is fixedly installed on the outer wall of the screw rod 214, and a second synchronous belt 216 is sleeved on the outer wall of the second synchronous wheel 212;

[0027] The grinding mechanism 3 includes a stable shaft seat 32, a transmission cylinder 30 is rotatably mounted on one end of the fixed plate 21, a transmission rod 31 is slidably clamped inside the transmission cylinder 30, a grinding wheel 33 is fixedly mounted on the outer wall of the transmission rod 31, and a fourth synchronous wheel 35 is fixedly mounted on the outer wall of the grinding wheel 33;

[0028] The front-to-back adjustment structure 23 is fixedly installed inside the support frame 22, the moving part of the front-to-back adjustment structure 23 is fixed to the lower end of the fixed frame seat 210, the outer frame of the upper and lower adjustment structure 24 is fixed to the other end of the grinding box 1, the screw 214 is threadedly connected to the inside of the threaded seat 213, the third synchronous wheel 215 is arranged to be driven by the second synchronous belt 216, and the first synchronous belt 29 is arranged to be driven by the fourth synchronous wheel 35;

[0029] A shielding shell 34 is provided above the grinding wheel 33, one end of the shielding shell 34 is fixed to one end of the stabilizing shaft seat 32, the transmission rod 31 is rotatably mounted inside the stabilizing shaft seat 32, and the lower end of the stabilizing shaft seat 32 is fixed to the upper end of the movable frame plate 28;

[0030] A support frame 11 is fixedly mounted on the lower end of the polishing box 1 , a protective shell 13 is fixedly mounted on the outer wall of the movable frame plate 28 , and a transmission cylinder 30 , a transmission rod 31 and a stabilizing shaft seat 32 are all located inside the protective shell 13 .

[0031] The specific configuration and function of this embodiment are described in detail below. By manipulating the operation of the up-down adjustment structure 24, the up-down adjustment structure 24 drives the structures of other adjustment mechanisms 2 to move up and down through the movable plate 25, and the adjustment mechanism 2 drives the grinding mechanism 3 to move up and down, and moves to the appropriate position to operate the front-back adjustment structure 23 to operate. The front-back adjustment structure 23 drives the movable frame plate 28 to move through the fixed frame seat 210, so that the fixed frame seat 210 drives the stable shaft seat 32 to move through the movable frame plate 28, and the grinding wheel can be driven through the stable shaft seat 32 and the transmission rod 31 The grinding wheel 33 is moved, and then the grinding wheel 33 can be moved to a suitable position, which is convenient for grinding the profile, and then the servo motor 26 is started, and the output end of the servo motor 26 drives the rotating rod 211 to rotate, and the rotating rod 211 drives the second synchronous wheel 212 and the first synchronous wheel 27 to rotate, and the second synchronous wheel 212 and the first synchronous wheel 27 drive the third synchronous wheel 215 and the fourth synchronous wheel 35 to rotate through the second synchronous belt 216 and the first synchronous belt 29, and the third synchronous wheel 215 drives the screw rod 214 to rotate, so that the screw rod 214 rotates on the internal thread of the threaded seat 213. The threaded seat 213 moves left and right along the outer wall of the screw rod 214 because the threaded seat 213 slides with the fixed frame seat 210 through the movable frame plate 28, and the threaded seat 213 drives the movable frame plate 28 to slide left and right on the fixed frame seat 210, and the movable frame plate 28 drives the stable shaft seat 32 to move left and right, thereby driving the grinding wheel 33 to move left and right, and moving the grinding wheel 33 to a suitable position at the edge of the profile, and the stable shaft seat 32 will drive the transmission rod 31 to move together when moving left and right, so that the transmission rod 31 moves left and right inside the transmission cylinder 30. The fourth synchronous wheel 35 rotates, and the fourth synchronous wheel 35 drives the transmission cylinder 30 to rotate, and the transmission cylinder 30 drives the transmission rod 31 to rotate inside the stable shaft seat 32, so that the transmission rod 31 drives the grinding wheel 33 to rotate, which is convenient for the grinding wheel 33 to grind the edges and corners of the profile. In summary, the grinding wheel 33 can be moved to the appropriate position of the edge and corner of the profile, so that the edges and corners of the profiles with different special shapes can be completely polished, so that the grinding effect meets the ideal, and at the same time, the surface of the profile will not be scratched during the grinding process, and the integrity of the profile will not be affected;

[0032] Under the sliding engagement of the transmission rod 31 and the transmission cylinder 30, when the transmission rod 31 moves, the transmission rod 31 can slide inside the transmission cylinder 30, which is convenient for adjusting the length of the transmission rod 31 and the transmission cylinder 30. The edge transmission rod 31 drives the grinding wheel 33 to rotate, which is convenient for the grinding wheel 33 to grind the edges and corners of the profile normally. The setting of the shielding shell 34 can shield the grinding wheel 33 to prevent waste chips from splashing during grinding, which can protect the surrounding staff and improve safety.

[0033] Under the sliding cooperation between the movable frame plate 28 and the fixed frame seat 210, the movable frame plate 28 can slide left and right on the upper end of the fixed frame seat 210, so that the movable frame plate 28 can be more stable during movement;

[0034] The setting of the protective support 12 can guide the waste chips after grinding, so that the waste chips can be moved to the bottom end of the grinding box 1, which is convenient for the waste chips to be discharged from the bottom end of the grinding box 1, and the waste chips can be collected in a centralized manner;

[0035] The provision of the protective shell 13 can protect the transmission cylinder 30 , the transmission rod 31 , the stabilizing shaft seat 32 and the protective shell 13 , thereby preventing foreign matter from entering the interior of the transmission cylinder 30 and the stabilizing shaft seat 32 .

[0036] Embodiment 2: Figure 1 , Figure 2 , Figure 4 and Figure 5 As shown, the fixing mechanism 4 includes a cylinder 41 and a support block 42, a lower pressure plate 43 is arranged above the support block 42, a vertical groove 44 is opened at the upper end of the grinding box 1, a connecting frame plate 45 is fixedly installed on the upper end of the lower pressure plate 43, a long plate 46 is slidably installed inside the vertical groove 44, one end of the cylinder 41 is fixed to one end of the grinding box 1, the lower end of the support block 42 is fixed to the upper end of the protective support 12, the protruding end of the cylinder 41 is fixed to the lower end of the long plate 46, and the upper end of the connecting frame plate 45 is fixed to the lower end of the long plate 46.

[0037] The effect achieved by the entire embodiment is that the cylinder 41 is started, and the extended end of the cylinder 41 drives the long plate 46 to slide downward inside the vertical groove 44, and the long plate 46 drives the lower pressure plate 43 to move downward together through the connecting frame plate 45, so that the lower pressure plate 43 moves toward the support block 42, and then the profile on the support block 42 can be squeezed, so that the profile can be fixed on the support block 42 to prevent the profile from moving during grinding.

[0038] The method of using and working principle of the device are as follows: first, the profile is placed on the polishing box 1, and the lower end of the profile contacts the support block 42, and then the cylinder 41 is started, and the extended end of the cylinder 41 drives the long plate 46 to slide downward inside the vertical slot 44, and the long plate 46 drives the lower pressing plate 43 to move downward together through the connecting frame plate 45, so that the lower pressing plate 43 moves toward the support block 42, and then the profile on the support block 42 can be squeezed, and the profile can be fixed on the support block 42. Finally, by operating the upper and lower adjustment structure 24, the upper and lower adjustment structure 24 drives other The structure of the adjusting mechanism 2 moves up and down, and the adjusting mechanism 2 drives the grinding mechanism 3 to move up and down, and moves to the appropriate position to operate the front and rear adjusting structure 23. The front and rear adjusting structure 23 drives the movable frame plate 28 to move through the fixed frame seat 210, so that the fixed frame seat 210 drives the stable shaft seat 32 to move through the movable frame plate 28, and the grinding wheel 33 can be driven to move through the stable shaft seat 32 and the transmission rod 31, and then the grinding wheel 33 can be moved to the appropriate position, which is convenient for grinding the profile, and then the servo motor 26 is started, and the output end of the servo motor 26 drives the rotating rod 211 to rotate, and the rotating rod 2 The second synchronous wheel 212 and the first synchronous wheel 27 are driven to rotate by the second synchronous wheel 212 and the first synchronous wheel 27, and the second synchronous wheel 212 and the first synchronous wheel 27 drive the third synchronous wheel 215 and the fourth synchronous wheel 35 to rotate through the second synchronous belt 216 and the first synchronous belt 29, and the third synchronous wheel 215 drives the screw rod 214 to rotate, so that the screw rod 214 rotates on the internal thread of the threaded seat 213, and because the threaded seat 213 is slidably matched with the fixed frame seat 210 through the movable frame plate 28, the threaded seat 213 moves left and right along the outer wall of the screw rod 214, and the threaded seat 213 drives the movable frame plate 28 to move left and right on the fixed frame seat 210. The movable frame 28 drives the stabilizing shaft seat 32 to move left and right, and then drives the grinding wheel 33 to move left and right, and moves the grinding wheel 33 to a suitable position at the edge and corner of the profile. When the stabilizing shaft seat 32 moves left and right, it drives the transmission rod 31 to move together, so that the transmission rod 31 slides left and right inside the transmission cylinder 30. When the fourth synchronous wheel 35 rotates, the fourth synchronous wheel 35 drives the transmission cylinder 30 to rotate, and the transmission cylinder 30 drives the transmission rod 31 to rotate inside the stabilizing shaft seat 32, so that the transmission rod 31 drives the grinding wheel 33 to rotate, so that the grinding wheel 33 can grind the edge and corner of the profile.

[0039] The above are only preferred embodiments of the present invention, and are not intended to limit the present invention in other forms. Any technician familiar with the profession may use the technical contents disclosed above to change or modify them into equivalent embodiments with equivalent changes and apply them to other fields. However, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention without departing from the technical solution of the present invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A device for grinding corners of thermal management profiles for new energy vehicles, comprising a grinding box (1), characterized in that: A protective support (12) is fixedly mounted on the inner side wall of the polishing box (1); an adjustment mechanism (2) is arranged at one end of the polishing box (1); a polishing mechanism (3) is arranged at the upper end of the adjustment mechanism (2); and a fixing mechanism (4) is arranged at the upper end of the polishing box (1); The adjustment mechanism (2) comprises a fixed plate (21), a front-rear adjustment structure (23) and an up-down adjustment structure (24); a movable plate (25) is fixedly mounted on a movable portion on one side of the up-down adjustment structure (24); a support frame (22) is fixedly mounted on one end of the movable plate (25); a servo motor (26) is fixedly mounted on one end of the fixed plate (21); a fixed frame seat (210) is fixedly mounted on the movable portion at the upper end of the front-rear adjustment structure (23); a rotating rod (211) is fixedly mounted on the output end of the servo motor (26); and an outer wall of the rotating rod (211) and a fixed portion at an edge thereof are fixedly mounted. A first synchronous wheel (27) is fixedly installed, a second synchronous wheel (212) is fixedly installed on the outer wall of the rotating rod (211), a first synchronous belt (29) is sleeved on the outer wall of the first synchronous wheel (27), a movable frame plate (28) is slidably installed on the upper end of the fixed frame seat (210), a threaded seat (213) is fixedly installed on the lower end of the movable frame plate (28), a screw rod (214) is rotatably installed on one end of the fixed plate (21), a third synchronous wheel (215) is fixedly installed on the outer wall of the screw rod (214), and a second synchronous belt (216) is sleeved on the outer wall of the second synchronous wheel (212); The grinding mechanism (3) comprises a stable shaft seat (32), a transmission cylinder (30) is rotatably mounted on one end of the fixed plate (21), a transmission rod (31) is slidably engaged inside the transmission cylinder (30), a grinding wheel (33) is fixedly mounted on the outer wall of the transmission rod (31), and a fourth synchronous wheel (35) is fixedly mounted on the outer wall of the grinding wheel (33).

2. The edge and corner grinding device of a thermal management profile for a new energy vehicle according to claim 1 is characterized in that: The fixing mechanism (4) comprises a cylinder (41) and a support block (42), a lower pressing plate (43) is arranged above the support block (42), a vertical groove (44) is opened at the upper end of the polishing box (1), a connecting frame plate (45) is fixedly installed at the upper end of the lower pressing plate (43), and a long plate (46) is slidably installed inside the vertical groove (44).

3. The edge and corner grinding device of a thermal management profile for a new energy vehicle according to claim 1 is characterized in that: The front-to-back adjustment structure (23) is fixedly installed inside the support frame (22), the movable part of the front-to-back adjustment structure (23) is fixed to the lower end of the fixed frame seat (210), and the outer frame of the upper and lower adjustment structure (24) is fixed to the other end of the polishing box (1).

4. The edge and corner grinding device of a thermal management profile for a new energy vehicle according to claim 1 is characterized in that: A shielding shell (34) is arranged above the grinding wheel (33), one end of the shielding shell (34) is fixed to one end of the stabilizing shaft seat (32), the transmission rod (31) is rotatably mounted inside the stabilizing shaft seat (32), and the lower end of the stabilizing shaft seat (32) is fixed to the upper end of the movable frame plate (28).

5. The edge and corner grinding device of a thermal management profile for a new energy vehicle according to claim 2 is characterized in that: One end of the cylinder (41) is fixed to one end of the polishing box (1), the lower end of the support block (42) is fixed to the upper end of the protective support (12), the extended end of the cylinder (41) is fixed to the lower end of the long plate (46), and the upper end of the connecting frame plate (45) is fixed to the lower end of the long plate (46).

6. The edge and corner grinding device of a thermal management profile for a new energy vehicle according to claim 1 is characterized in that: A support frame (11) is fixedly mounted on the lower end of the polishing box (1), a protective shell (13) is fixedly mounted on the outer wall of the movable frame plate (28), and the transmission cylinder (30), the transmission rod (31) and the stabilizing shaft seat (32) are all located inside the protective shell (13).

7. The edge and corner grinding device for thermal management profiles of new energy vehicles according to claim 3 is characterized in that: The screw rod (214) is threadedly connected to the inside of the threaded seat (213); the third synchronous wheel (215) is arranged to be driven by the second synchronous belt (216); and the first synchronous belt (29) is arranged to be driven by the fourth synchronous wheel (35).

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