Double-end same-direction take-up device

Abstract

The utility model discloses a double-end same-direction take-up device, relates to the technical field of photovoltaic welding strip processing, and solves the problem that the orientations of a thick surface and a thin surface are inconsistent when a photovoltaic welding strip is taken up in an existing take-up host. The two take-up modules are fixedly mounted on the rotary table; the rotary driving mechanism is in driving connection with the rotary disc so as to drive the rotary disc to rotate, and the positions of the two take-up modules are switched; each take-up module comprises a clamping mechanism used for clamping a wire coil, a take-up mechanism used for driving the wire coil to rotate and a take-up control mechanism used for driving the wire coil to axially move relative to the rotary disc, and a wire hooking device and a cutter are arranged on each take-up module. According to the utility model, the rotary table is controlled to rotate clockwise by 180 degrees, and the positions of the two take-up modules are switched, so that the photovoltaic welding strip can be uniformly wound on a wire coil, the orientations of the thick and thin surfaces of the welding strip are consistent, and the arrangement specification of the welding strip can be ensured.

Description

Technical Field

[0001] The utility model relates to the technical field of photovoltaic welding ribbon processing, in particular to a double-headed same-direction wire-taking device. Background Art

[0002] Tin-coated copper solder ribbon is a key material in the manufacture of photovoltaic equipment. Traditionally, solder ribbon was fully tinned, ensuring a uniform tin thickness across the ribbon. However, with increasing industry quality and cost requirements, and the need for cost reduction and efficiency improvement, the need for resist coating or thin coating on the non-welding side of the ribbon has emerged to further reduce costs. This is particularly true for flat wire solder ribbon, typically produced using the BC process. Because the tin coating can vary in thickness on both sides, the production of this type of ribbon requires that all soldering surfaces face the same direction.

[0003] Currently, the main types of wire-winding devices on the market are double-ended, same-direction wire-winding devices and double-ended, opposite-direction axial wire-winding devices. However, current take-up machines are unable to meet these requirements. Same-direction wire-winding devices struggle to meet acceptable wire-winding requirements when producing flat wire. Opposite-direction axial wire-winding devices can accommodate all wire types (round, flat, segmented, and special-shaped) but cannot meet future requirements for varying thicknesses of tinned ribbon. Because the tin coating thickness on the front and back of photovoltaic ribbon varies, it is necessary to ensure that the thick and thin sides of the ribbon on both reels face the same direction. However, current devices do not allow for the thick and thin sides of the ribbon to face each other when the two reels alternately take up the ribbon. Utility Model Content

[0004] The purpose of the utility model is to solve the above problems and design a double-headed same-direction take-up device to solve the problem that the existing take-up host has inconsistent directions of the thick and thin surfaces when taking up the photovoltaic welding ribbon.

[0005] To achieve the above-mentioned purpose, the technical solution of the present invention is a double-ended same-direction take-up device, comprising:

[0006] turntable;

[0007] Two take-up modules are fixedly mounted on the turntable;

[0008] A rotary drive mechanism, the rotary drive mechanism being drivably connected to the turntable to drive the turntable to rotate and switch the positions of the two take-up modules;

[0009] The wire taking-up module includes a clamping mechanism for clamping the wire drum, a wire taking-up mechanism for driving the wire drum to rotate, and a wire taking-up control mechanism for driving the wire drum to move axially relative to the turntable. Each wire taking-up module is provided with a wire hook and a cutter, and the wire hook and the cutter are both located on the rotation path of the wire drum.

[0010] Preferably, it also includes a box body, the turntable is vertically arranged on the front side of the box body and is rotatably connected to the box body through a bearing, the rotary drive mechanism is installed on the rear side of the box body, and the two take-up modules are symmetrically distributed on the turntable.

[0011] Preferably, the rotation drive mechanism includes a motor fixedly mounted on a fixed plate, a reducer connected to the motor for transmission, and a rotating shaft connected to the box for rotation. A small gear is installed at the output end of the reducer, a large gear is installed on the rotating shaft, the small gear is meshed with the large gear, and one end of the rotating shaft is fixedly connected to the center of the turntable.

[0012] Preferably, the wire-winding control mechanism includes a mounting plate, a fixed plate slidably connected to the mounting plate through a slider, a servo motor fixedly mounted on the mounting plate, and a screw rod connected to the output end of the servo motor through a coupling, the screw rod is transmission-connected to the bottom of the fixed plate, and the clamping mechanism and the wire-winding mechanism are both mounted on the fixed plate.

[0013] Preferably, the wire-taking mechanism includes a bearing seat, a main shaft rotatably connected to the bearing seat, a positioning head and a synchronous wheel respectively installed at the front and rear ends of the main shaft, and a wire-taking motor that drives the synchronous wheel to rotate.

[0014] Preferably, the clamping mechanism includes a vertical plate fixed vertically on the fixed plate, a clamping plate horizontally slidably connected to one side of the vertical plate, a clamping cylinder driving the clamping plate to move, a locking flange rotatably connected to the inner side of the clamping plate, and a chuck fixedly mounted on the front end of the main shaft, the locking flange and the chuck are arranged opposite to each other, and there is a clamping space between the locking flange and the chuck for accommodating the wire reel.

[0015] Preferably, the thread hook includes a pressure block, a guide bolt threadedly connected to the pressure block, a return spring sleeved on the guide bolt, and a clip fixedly mounted on the pressure block. A notch is provided on the circumference of the chuck, the pressure block is located in the notch, the guide bolt passes through the chuck and is threadedly connected to the pressure block, and the two ends of the return spring are respectively in contact with the chuck and the guide bolt.

[0016] Preferably, a pressure cylinder is provided on one side of the bearing seat, and an output end of the pressure cylinder is connected to a push rod, and the push rod is in contact with the guide bolt.

[0017] Preferably, a transition wheel is provided on one side of each take-up module, and both transition wheels are located on the circumference of the turntable.

[0018] Preferably, a pull rod capable of moving along the axial direction of the turntable and two support rods are provided between the two take-up modules. The two support rods are respectively located at both ends of the pull rod and are close to the two take-up modules.

[0019] Compared with the prior art, the beneficial effects are:

[0020] The center wire reel of the utility model is clamped and fixed by a clamping mechanism. When the wire taking-up action is performed, the photovoltaic welding ribbon is wound around one of the wire taking-up modules, and then the wire taking-up mechanism controls the rotation of the wire reel, and at the same time, the wire taking-up control mechanism controls the linear movement of the wire reel, so that the welding ribbon is evenly wound onto the wire reel. When the wire taking-up module reaches the wire taking-up threshold set by the system, the rotary drive mechanism controls the turntable to rotate 180° clockwise, the positions of the two wire taking-up modules are interchanged, and the other wire taking-up module is started, and the photovoltaic welding ribbon is hooked by the wire hooker, and the cutter captures the welding ribbon at the same time, and the welding ribbon is cut off during the rotation of the turntable. In this reciprocating manner, the photovoltaic welding ribbon is evenly wound onto the wire reel, and the orientation of the thick and thin surfaces of the welding ribbon is guaranteed to be consistent, and the arrangement specifications of the photovoltaic welding ribbon on the wire reel can also be guaranteed. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a structural diagram of the double-headed, same-direction take-up device of the present invention when it is installed on a frame;

[0022] Figure 2 This is a schematic diagram of the installation structure of the wire bow assembly;

[0023] Figure 3 It is a structural diagram of a double-headed, same-direction take-up device;

[0024] Figure 4 This is a structural diagram of a double-headed, same-direction take-up device from another perspective;

[0025] Figure 5 yes Figure 4 A magnified view of the structure at point A;

[0026] Figure 6 This is a schematic diagram of the internal structure of the box in a double-headed, same-direction take-up device;

[0027] Figure 7 This is a structural diagram of the wire-taking module in the double-headed, same-direction wire-taking device;

[0028] Figure 8 This is a structural diagram of the take-up module from another perspective;

[0029] Figure 9 It is a structural diagram of the thread hook device on the chuck.

[0030] In the figure, 1. frame; 2. box; 3. take-up module; 31. take-up control mechanism; 311. mounting plate; 312. servo motor; 313. screw; 314. fixing plate; 32. take-up mechanism; 321. bearing seat; 322. take-up motor; 323. synchronous wheel; 324. spindle; 325. positioning head; 33. clamping mechanism; 331. vertical plate; 332. clamping plate; 333. locking flange; 334. chuck; 4. column; 5. potentiometer rocker assembly; 6. wire bow assembly; 61. lifting Module; 62. Wire bow; 63. Adjustment column; 64. Connecting rod; 65. Steel wire; 66. Guide wheel; 7. Turntable; 8. Rotary drive mechanism; 81. Motor; 82. Reducer; 83. Small gear; 84. Large gear; 85. Rotating shaft; 9. Electric slip ring; 10. Transition wheel; 11. Cutter; 12. Support rod; 13. Pull rod; 14. Tensioning cylinder; 15. Wire hook; 151. Pressure block; 152. Guide bolt; 153. Return spring; 154. Clip; 16. Push cylinder; 17. Push rod. DETAILED DESCRIPTION

[0031] The following is a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0032] like Figure 1-Figure 4 As shown, a preferred embodiment of the utility model proposes a double-headed same-direction wire-taking device, which includes a frame 1, a box 2, a turntable 7, a rotary drive mechanism 8 and two wire-taking modules 3. The two wire-taking modules 3 can complete the same-direction wire-taking of the photovoltaic welding strip.

[0033] A column 4 is provided on the frame 1 , on which a potentiometer rocker assembly 5 and a wire bow 62 assembly 6 are mounted. The potentiometer rocker assembly 5 is located below the wire bow 62 assembly 6 .

[0034] refer to Figure 2 The wire bow 62 assembly 6 is composed of a lifting module 61, a wire bow 62 and a guide wheel 66. The lifting module 61 is driven by a servo motor-screw. The wire bow 62 is fixedly mounted on a connecting plate. One end of the connecting plate is drive-connected to the lifting module 61 and is rotationally connected to the connecting plate at the guide wheel 66.

[0035] The shape of the wire bow 62 resembles an arc. It has an arc-shaped hole, which contains a bolt for securing it to the connecting plate. The arc-shaped hole allows for adjustment of the angle of the wire bow 62. Adjustment posts 63 are fixed to each end of the wire bow 62. These posts have holes, each of which is connected to a connecting rod 64. The connecting rods 64 are inserted into the holes and then secured with screws.

[0036] Two steel wires 65 are connected to the lower ends of the two connecting rods 64. These wires 65 are parallel to each other, with their ends fixed to the two connecting rods 64. The two wires 65 are positioned below the guide wheel 66, with a gap between them to help position the front and back of the photovoltaic ribbon. The height of the wire bow 62 can be adjusted using the lifting module 61.

[0037] The potentiometer rocker assembly 5 has a tensioning wheel that can swing up and down. The photovoltaic welding ribbon passes through the tensioning wheel, the guide wheel 66 and the gap between the two steel wires 65 in sequence, and then passes through the take-up module 3, and the photovoltaic welding ribbon is taken up by the take-up module 3.

[0038] refer to Figure 6 The housing 2 is fixedly mounted on the frame 1, and the turntable 7 is located at the front side of the housing 2 and is vertically arranged and rotatably connected to the housing 2 via a bearing. The two take-up modules 3 are symmetrically mounted on the turntable 7, that is, the positions of the two take-up modules 3 can be switched every 180° rotation of the turntable 7.

[0039] like Figure 6 As shown, the rotary drive mechanism 8 is located at the rear side of the housing 2 and consists of a motor 81, a reducer 82, and a rotating shaft 85. The rotating shaft 85 passes through the housing 2 and is fixedly connected to the center of the turntable 7. Both ends of the rotating shaft 85 are rotatably connected to the housing 2 via bearings. The motor 81 and the reducer 82 are both located outside the housing 2, with the reducer 82 fixed to the housing 2. The motor 81 is a three-phase asynchronous motor, and the reducer 82 is a worm gear reducer.

[0040] The three-phase asynchronous motor is connected to the worm gear reducer 82 in a transmission manner. A large gear 84 is fixedly mounted on the rotating shaft 85, and a small gear 83 is fixedly mounted on the output end of the worm gear reducer 82. The large gear 84 and the small gear 83 are engaged. The rotation of the three-phase asynchronous motor will transmit power to the small gear 83 through the worm gear reducer 82. The small gear 83 will drive the large gear 84 to rotate, thereby driving the rotating shaft 85 to rotate, and finally driving the turntable 7 to rotate in the vertical plane.

[0041] The rotating shaft 85 is hollow, with an electric slip ring 9 mounted at its rear end. The cables connecting the two take-up modules 3 on the turntable 7 pass through the interior of the rotating shaft 85 and are then connected to the electric slip ring 9. The electric slip ring 9 is then connected to an external control box to power and control the take-up modules 3. As the rotating shaft 85 rotates, the electric slip ring 9 prevents the cables connecting the two take-up modules 3 from becoming tangled or knotted.

[0042] like Figure 7 、 Figure 8 As shown, each take-up module 3 consists of three parts: a clamping mechanism 33, a take-up mechanism 32, and a take-up control mechanism 31. The clamping mechanism 33 is used to clamp the wire drum, the take-up mechanism 32 is used to control the rotation of the wire drum, and the take-up control mechanism 31 controls the movement of the wire drum relative to the axial direction of the wire drum (i.e., the axial direction of the turntable 7) so that the photovoltaic welding ribbon is evenly wound onto the wire drum.

[0043] The wire take-up control mechanism 31 comprises a mounting plate 311, a servo motor 312, a fixed plate 314, and a screw rod 313. The mounting plates 311 in the two wire take-up modules 3 are fixedly connected by a connector, enclosing the rotating shaft 85 and rotating along with the rotating shaft 85. The fixed plate 314 is slidably connected to a slide rail fixed to the mounting plate 311 via a slider, and the sliding direction is consistent with the axial direction of the wire reel.

[0044] The screw rod 313 is rotatably connected to two screw rod 313 holders fixed to the mounting plate 311. The bottom of the fixed plate 314 is in driving connection with the screw rod 313. The output end of the servo motor 312 is connected to the screw rod 313 via a coupling. When the servo motor 312 rotates, it drives the screw rod 313, thereby causing the fixed plate 314 to slide relative to the mounting plate 311. The clamping mechanism 33 and the wire take-up mechanism 32 are both mounted on the mounting plate 311.

[0045] like Figure 8 As shown, the wire-taking mechanism 32 is composed of a bearing seat 321, a main shaft 324, a positioning head 325, a synchronous wheel 323 and a wire-taking motor 322. The bearing seat 321 is fixedly bolted to the fixed plate 314, and the main shaft 324 is horizontally rotatably connected to the bearing seat 321. The positioning head 325 and the synchronous wheel 323 are respectively mounted on the front and rear ends of the main shaft 324. The wire-taking motor 322 is horizontally fixedly mounted on the motor mounting plate. A synchronous wheel 323 is also installed at the output end of the servo motor 312, and the two synchronous wheels 323 are connected by a synchronous belt. The main shaft 324 will cooperate with the clamping mechanism 33 to clamp the wire drum, and then the servo motor 312 controls the main shaft 324 to rotate, thereby driving the wire drum to rotate and winding the photovoltaic welding tape.

[0046] The clamping mechanism 33 is composed of a vertical plate 331, a clamping plate 332, a locking flange 333, a clamping cylinder, a chuck 334 and other components, wherein the vertical plate 331 is vertically fixed on the fixed plate, the clamping plate 332 is horizontally slidably connected to the slide rail fixed on the side of the vertical plate 331 through a slider, the clamping cylinder is horizontally fixed on the cylinder fixing plate, the output end of the clamping cylinder is connected to the clamping plate 332, the clamping plate 332 is in the shape of an "L", the locking flange 333 is located at the L end of the clamping plate 332, and is rotatably connected to the inner side of the clamping plate 332, and a positioning head 325 is also provided on the inner side of the clamping plate 332, and the positioning head 325 protrudes outward through the locking flange 333.

[0047] The chuck 334 is fixedly connected to the front end of the spindle 324, and the positioning head 325 at the front end of the spindle 324 also protrudes outward through the chuck 334. The two positioning heads 325 respectively position the ends of the wire drum. The locking flange 333 faces the chuck 334. Therefore, the clamping cylinder controls the movement of the clamping plate 332. The locking flange 333 and the chuck 334 cooperate to clamp the ends of the wire drum. When the spindle 324 rotates, the wire drum rotates.

[0048] refer to Figure 9 There is a notch on the circumference of the chuck 334 for installing the thread hook 15. The thread hook 15 is composed of a pressure block 151, a guide bolt 152, a return spring 153 and a clip 154. The pressure block 151 is located in the notch on the chuck 334. The shape of the pressure block 151 is consistent with the shape of the notch and can just fill the notch. The guide bolt 152 is located on the back side of the chuck 334 (i.e., the side away from the wire reel). The guide bolt 152 passes through the chuck 334 and is threadedly connected to the pressure block 151. The return spring 153 is sleeved on the guide bolt 152, and the two ends of the return spring 153 are respectively in contact with the chuck 334 and the guide bolt 152. When the return spring 153 is at its original length, the pressure block 151 is located in the notch.

[0049] One end of the clip 154 ​​is bent outward at a certain angle. The clip 154 ​​is fixed to the pressure block 151 by screws. A top-pressure cylinder 16 is installed on the bearing seat 321, and the output end of the top-pressure cylinder 16 is connected to a push rod 17. In the initial state, the push rod 17 will abut against or not contact the guide bolt 152. At the beginning or end of the wire-winding operation, the top-pressure cylinder 16 will control the movement of the push rod 17, and the push rod 17 will push the guide bolt 152 outward. At this time, the pressure block 151 is subjected to the top pressure of the guide bolt 152 and is disengaged from the gap, so that the clip 154 ​​moves to the rotation path of the wire drum. The bent end of the clip 154 ​​will hook the wire to constrain the photovoltaic welding ribbon.

[0050] refer to Figure 4 、 Figure 5A pull rod 13 is set between the two take-up modules 3, and the pull cylinder is connected to the output end of the tensioning cylinder 14. The tensioning cylinder 14 is fixedly installed on the inner side of the turntable 7. The tensioning cylinder 14 can control the pull rod 13 to move along the axial direction of the turntable 7.

[0051] Each take-up module 3 is equipped with a cutter 11, a transition wheel 10, and a support rod 12. The support rod 12 is a bow-shaped rod. The two transition wheels 10 are symmetrically located on opposite sides of the two take-up modules 3. The two support rods 12 are located between the two take-up modules 3, on either side of the pull rod 13 and close to the pull rod 13. The two cutters 11 are also symmetrically located on the side of the two take-up modules 3 that are close to each other.

[0052] When the winding starts, one end of the photovoltaic welding ribbon is clamped by a hook, and then the wire drum is controlled to rotate and move along the axial direction of the wire drum. The photovoltaic welding ribbon is evenly wound onto the wire drum, and the thick and thin sides of the photovoltaic welding ribbon are in the same direction.

[0053] When the reel is full, the turntable 7 rotates, and the photovoltaic ribbon is wound onto the transition wheel 10 next to the other take-up module 3. The transition wheel 10 has a groove that limits the position of the photovoltaic ribbon. Then, the tensioning cylinder 14 controls the movement of the pull rod 13. The two ends of the pull rod 13 pull the photovoltaic ribbon inward (i.e., axially of the turntable 7), causing the center of the photovoltaic ribbon to sag inward. At the same time, the two support rods 12 support the ends of the photovoltaic ribbon at the sag, preventing the photovoltaic ribbon from escaping from the transition wheel 10. Because the pull rod 13 hooks the photovoltaic ribbon, the photovoltaic ribbon is in the rotation path of the cutter 11. At this time, the turntable 7 continues to rotate until it rotates 180°. The photovoltaic ribbon is cut by the blade. At the same time, the wire hook 15 on the other take-up module 3 extends under the action of the push cylinder 16, hooking the cut end of the photovoltaic ribbon as the reel rotates, and then the take-up operation is repeated.

[0054] At this point, the two take-up modules 3 swap positions. The other reel, having finished taking up the ribbon, can then be unloaded and reloaded. This rotation keeps the ribbon in place, while the reels switch positions to ensure the ribbon's thick and thin sides face the same direction during take-up.

[0055] The above technical solutions only reflect the preferred technical solutions of the present utility model. Any changes that may be made to certain parts thereof by technicians in this technical field all reflect the principles of the present utility model and fall within the scope of protection of the present utility model.

Claims

1. A double-ended same-direction take-up device, characterized in that: include: Turntable (7); Two wire-receiving modules (3) are fixedly mounted on the turntable (7); A rotary drive mechanism (8), the rotary drive mechanism (8) is drivingly connected to the turntable (7) to drive the turntable (7) to rotate and switch the positions of the two take-up modules (3); The wire take-up module (3) comprises a clamping mechanism (33) for clamping the wire drum, a wire take-up mechanism (32) for driving the wire drum to rotate, and a wire take-up control mechanism (31) for driving the wire drum to move axially relative to the turntable (7). Each wire take-up module (3) is provided with a wire hook (15) and a cutter (11), and the wire hook (15) and the cutter (11) are both located on the rotation path of the wire drum.

2. A double-ended same-direction take-up device according to claim 1, characterized in that: It also includes a box (2), the turntable (7) is vertically arranged on the front side of the box (2) and is rotatably connected to the box (2) through a bearing, the rotary drive mechanism (8) is installed on the rear side of the box (2), and the two take-up modules (3) are symmetrically distributed on the turntable (7).

3. A double-ended same-direction take-up device according to claim 2, characterized in that: The rotary drive mechanism (8) comprises a motor (81) fixedly mounted on a fixed plate (314), a reducer (82) transmission-connected to the motor (81), and a rotating shaft (85) rotationally connected to the housing (2); a small gear (83) is mounted on the output end of the reducer (82); a large gear (84) is mounted on the rotating shaft (85); the small gear (83) meshes with the large gear (84); and one end of the rotating shaft (85) is fixedly connected to the center of the turntable (7).

4. A double-ended same-direction take-up device according to claim 1, characterized in that: The wire-taking control mechanism (31) comprises a mounting plate (311), a fixed plate (314) slidably connected to the mounting plate (311) via a slider, a servo motor (312) fixedly mounted on the mounting plate (311), and a screw rod (313) connected to the output end of the servo motor (312) via a coupling, wherein the screw rod (313) is transmission-connected to the bottom of the fixed plate (314), and the clamping mechanism (33) and the wire-taking mechanism (32) are both mounted on the fixed plate (314).

5. A double-ended same-direction take-up device according to claim 4, characterized in that: The wire-taking mechanism (32) comprises a bearing seat (321), a main shaft (324) rotatably connected to the bearing seat (321), a positioning head (325) and a synchronous wheel (323) respectively mounted at the front and rear ends of the main shaft (324), and a wire-taking motor (322) for driving the synchronous wheel (323) to rotate.

6. A double-ended same-direction take-up device according to claim 5, characterized in that: The clamping mechanism (33) includes a vertical plate (331) fixed vertically on the fixed plate (314), a clamping plate (332) horizontally slidably connected to one side of the vertical plate (331), a clamping cylinder for driving the clamping plate (332) to move, a locking flange (333) rotatably connected to the inner side of the clamping plate (332), and a clamping disc (334) fixedly mounted on the front end of the main shaft (324), the locking flange (333) and the clamping disc (334) being arranged opposite to each other, and a clamping space for accommodating a wire drum is provided between the locking flange (333) and the clamping disc (334).

7. A double-ended same-direction take-up device according to claim 6, characterized in that: The thread hook (15) includes a pressure block (151), a guide bolt (152) threadedly connected to the pressure block (151), a return spring (153) sleeved on the guide bolt (152), and a clamping piece (154) fixedly mounted on the pressure block (151). A notch is provided on the circumference of the chuck (334), and the pressure block (151) is located in the notch. The guide bolt (152) passes through the chuck (334) and is threadedly connected to the pressure block (151). The two ends of the return spring (153) are respectively in contact with the chuck (334) and the guide bolt (152).

8. A double-ended same-direction take-up device according to claim 7, characterized in that: A push-up cylinder (16) is provided on one side of the bearing seat (321), and an output end of the push-up cylinder (16) is connected to a push rod (17), and the push rod (17) is in contact with the guide bolt (152).

9. The double-ended same-direction take-up device according to claim 1, characterized in that: A transition wheel (10) is provided on one side of each take-up module (3), and both transition wheels (10) are located on the circumference of the turntable (7).

10. The double-ended same-direction take-up device according to claim 1, characterized in that: A pull rod (13) and two support rods (12) that can move along the axial direction of the turntable (7) are provided in the middle of the two take-up modules (3). The two support rods (12) are respectively located at both ends of the pull rod (13) and are close to the two take-up modules (3).

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