A pushing device for continuous printing of long trusses on track

Abstract

The present invention discloses a pushing device for continuous printing of long trusses on track, the pushing device comprises a frame, a control mechanism, and a first clamping mechanism, an intermediate clamping mechanism, and a second clamping mechanism sequentially distributed on the frame in the horizontal direction; each clamping mechanism comprises a clamping head at the top and a one-way roller at the bottom, the clamping head at the top clamps and releases the printed long trusses by reciprocating along the vertical direction; the intermediate clamping mechanism can be installed on the frame in a reciprocating manner in the horizontal direction, and can reciprocate between the first clamping mechanism and the second clamping mechanism; the rotation direction of the first one-way roller is the same as the rotation direction of the second one-way roller, and is opposite to the rotation direction of the intermediate one-way roller; the movement tangent direction of the vertex of the first one-way roller is consistent with the pushing direction of the long trusses. The above-mentioned pushing device can meet the task requirements of printing infinite long trusses on track.

Description

Technical Field

[0001] The invention relates to the field of advanced manufacturing technology, and in particular to a pushing device for continuously printing long trusses on track. Background Art

[0002] At present, common 3D printing equipment on the ground can be divided into three categories according to the structural type: Cartesian orthogonal structure, parallel arm structure and inclined infinite length 3D printer. Traditional Cartesian orthogonal structure and parallel arm structure 3D printers are generally only able to print parts within the forming size smaller than the device envelope, while the inclined infinite length 3D printer uses the principle of conveyor belts. By tilting the 3D print head at 45°, each layer of printing material is tilted and bonded to the conveyor belt and transmitted outward through the conveyor belt. Since the on-orbit space environment requires high-temperature and radiation-resistant high-performance resin materials, it is difficult to achieve firm bonding of high-performance resin materials and smooth detachment from the conveyor belt using the inclined infinite length 3D printing equipment using the conveyor belt, so it is impossible to achieve on-orbit printing of ultra-long structures.

[0003] Aiming at the task of building a large-scale space truss structure on track, the present invention designs a pushing device for continuously printing long trusses on track. Summary of the invention

[0004] In view of this, the present invention provides a pushing device for continuous printing of long trusses on track, which can meet the task requirements of printing infinitely long trusses on track.

[0005] The present invention adopts the following specific technical solutions:

[0006] A pushing device for continuous printing of long trusses on track, the pushing device comprising a frame, a control mechanism, and a first clamping mechanism, an intermediate clamping mechanism, and a second clamping mechanism sequentially distributed in a transverse direction;

[0007] The first clamping mechanism comprises a first clamping head and a first one-way roller; the first clamping head is mounted on the frame to reciprocate along a vertical direction, and the first one-way roller is located at the bottom of the first clamping head and can rotate in one direction;

[0008] The intermediate clamping mechanism is installed on the frame so as to be reciprocatingly movable in the lateral direction, and comprises an intermediate clamping head and an intermediate unidirectional roller arranged opposite to each other in the vertical direction; the intermediate clamping head is reciprocatingly movable in the vertical direction; the intermediate unidirectional roller is located at the bottom of the intermediate clamping head and is unidirectionally rotatable;

[0009] The second clamping mechanism comprises a second clamping head and a second one-way roller; the second clamping head is mounted on the frame so as to be reciprocatingly movable in a vertical direction; the second one-way roller is located at the bottom of the second clamping head and is unidirectionally rotatable;

[0010] The rotation direction of the first one-way roller is the same as that of the second one-way roller, and opposite to that of the middle one-way roller; the movement tangent direction of the vertex of the first one-way roller is consistent with the pushing direction of the long truss;

[0011] The control mechanism is used to control the actions of each clamping mechanism.

[0012] Furthermore, the frame includes four support rods arranged in parallel;

[0013] The support rod extends in the transverse direction and is used to support the intermediate clamping mechanism;

[0014] The intermediate clamping mechanism also includes a fixed bracket and a transverse driving mechanism; the fixed bracket is slidably matched with the four support rods; the transverse driving mechanism is fixedly installed on the frame and is connected to the control mechanism by signal, so as to drive the fixed bracket to slide along the support rods;

[0015] The intermediate clamping head and the intermediate one-way roller are both mounted on the fixed bracket.

[0016] Furthermore, the first clamping head, the intermediate clamping head and the second clamping head each include a clamping motor, a linear slide, a pressure sensor and a pressure block;

[0017] The clamping motor of the first clamping head and the clamping motor of the second clamping head are both fixedly mounted on the top of the frame; the clamping motor of the middle clamping head is fixedly mounted on the top of the fixed bracket;

[0018] The bottom end of the clamping motor is transmission-connected to the top end of the linear slide, and is used to drive the linear slide to reciprocate in the vertical direction;

[0019] The pressure sensor is fixedly mounted on the linear slide and is used to detect the pressure between the pressing block and the printed part;

[0020] The pressing block is fixedly mounted on the bottom end of the linear slide, and is used to cooperate with the corresponding one-way roller to clamp the long truss;

[0021] The control system is signal-connected to each clamping motor and each pressure sensor, and is used to control the corresponding clamping motor according to the pressure signal of the pressure sensor.

[0022] Furthermore, the first clamping mechanism, the intermediate clamping mechanism and the second clamping mechanism all include a support plate;

[0023] The support plate of the first clamping mechanism and the support plate of the second clamping mechanism are both fixedly mounted on the frame; the first one-way roller and the second one-way roller are both rotatably mounted on the corresponding support plate through a one-way bearing;

[0024] The support plate of the intermediate clamping mechanism is fixedly mounted on the fixed bracket; the intermediate one-way roller is rotatably mounted on the support plate of the intermediate clamping head via a one-way bearing.

[0025] Furthermore, the first clamping mechanism, the middle clamping mechanism and the second clamping mechanism each include three unidirectional rollers distributed in a triangle;

[0026] The rotation axes of the first one-way roller, the second one-way roller and the middle one-way roller are arranged perpendicular to both the horizontal and vertical directions.

[0027] Beneficial effects:

[0028] 1. The pushing device of the present invention is used for pushing the long truss that is continuously printed on the track, and the pushing device includes a first clamping mechanism, an intermediate clamping mechanism, and a second clamping mechanism that are sequentially distributed on the frame along the horizontal direction; each clamping mechanism includes a clamping head at the top and a one-way roller at the bottom, and the clamping head at the top clamps and releases the printed long truss by reciprocating along the vertical direction; the intermediate clamping mechanism can be installed on the frame in a reciprocating manner along the horizontal direction, and can reciprocate between the first clamping mechanism and the second clamping mechanism; the rotation direction of the first one-way roller is the same as the rotation direction of the second one-way roller, and is opposite to the rotation direction of the intermediate one-way roller; the movement tangent direction of the vertex of the first one-way roller is consistent with the pushing direction of the long truss; in the normal printing process of the long truss, the intermediate clamping mechanism clamps the printed long truss and pushes it along the printing direction, and the first and second clamping mechanisms are released, The printed long truss is supported on the first and second one-way rollers while being clamped by the intermediate clamping mechanism, and rolling friction with the first and second one-way rollers ensures that the friction of pushing the workpiece is minimal and the movement step is accurate; when the intermediate clamping mechanism moves from one end to the other end and needs to return, the first and second clamping mechanisms clamp the printed long truss, and the intermediate clamping mechanism is released. At this time, the first and second one-way rollers cannot rotate in the opposite direction, which increases the friction. The first and second clamping mechanisms in the clamped state and the long truss are converted into sliding friction, ensuring that the printed workpiece does not move, while the intermediate one-way roller can rotate in the opposite direction, so that the intermediate one-way roller and the long truss are in a rolling friction state, reducing the friction, thereby limiting the position change of the printed part during the resetting process of the intermediate clamping mechanism. This cycle is repeated to complete the task of pushing the infinite long truss printing on the track and accurately control the position of the printed workpiece.

[0029] 2. The frame of the pushing device of the present invention includes four support rods arranged in parallel; the support rods extend laterally and are used to support the intermediate clamping mechanism; the intermediate clamping mechanism also includes a fixed bracket and a transverse driving mechanism; the fixed bracket and the four support rods are slidably matched; the transverse driving mechanism is fixedly installed on the frame and is connected to the control mechanism signal to drive the fixed bracket to slide along the support rods; the intermediate clamping head and the intermediate unidirectional roller are both installed on the fixed bracket; the above structure can stably support the intermediate clamping mechanism, ensure the reciprocating movement of the intermediate clamping mechanism along the extension direction of the long truss, and realize the stable support of the long truss printed on the track, and the transverse driving mechanism can use a motor screw to drive the fixed bracket.

[0030] 3. Each clamping head of the pushing device of the present invention includes a clamping motor, a linear slide, a pressure sensor and a pressure block; each clamping head controls the movement of the linear slide in the vertical direction through the clamping motor to realize the clamping and loosening of the clamping mechanism, and judges the clamping state of the clamping mechanism on the printed workpiece through the pressure sensor, so as to realize stable clamping of the printed workpiece, avoid damage to the long truss due to excessive clamping force or unstable clamping due to insufficient clamping force, thereby improving the pushing effect.

[0031] 4. Each clamping mechanism of the pushing device of the present invention includes three one-way rollers distributed in a triangle. The three one-way rollers can increase the contact area with the long truss and provide stable support. At the same time, the one-way rollers can guide the pushing direction of the truss so that the truss is always pushed along the predetermined track. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic diagram of the overall structure of the pushing device of the present invention;

[0033] Figure 2 It is a schematic structural diagram of a first clamping head of a pushing device of the present invention;

[0034] Figure 3a-3d It is a schematic diagram of the working principle of the pushing device of the present invention.

[0035] Among them, 1-frame, 2-first clamping head, 3-first support plate, 4-middle clamping head, 5-middle support plate, 6-second clamping head, 7-second support plate, 8-support rod, 9-fixed bracket, 10-lateral drive mechanism, 11-clamping motor, 12-linear slide, 13-pressure sensor, 14-pressing block, 15-print head, 16-first one-way roller, 17-middle one-way roller, 18-second one-way roller, 19-long truss DETAILED DESCRIPTION

[0036] The present invention is described in detail below with reference to the accompanying drawings and embodiments.

[0037] The embodiment of the present invention provides a pushing device for continuously printing a long truss 19 on track, such as Figure 1 As shown in the structure, the pushing device includes a frame 1, a control mechanism, and a first clamping mechanism, an intermediate clamping mechanism, and a second clamping mechanism sequentially distributed in the transverse direction; Figure 1 In the coordinate system, the Z direction is defined as the horizontal direction, and the Y direction is defined as the vertical direction. The print head 15 is installed at the left end of the frame 1, and the printed truss 19 is pushed from the left side to the right side in the horizontal direction; the first clamping mechanism and the second clamping mechanism are fixed clamping mechanisms, that is, the horizontal positions of the first clamping mechanism and the second clamping mechanism cannot be adjusted; the middle clamping mechanism is a mobile clamping mechanism, which can move back and forth in the horizontal direction between the first clamping mechanism and the second clamping mechanism; wherein the middle clamping mechanism is a mobile clamping and pushing mechanism that can move along the Z direction, and is used to clamp the printed part during the printing process of the long truss structure. After each layer of material is accumulated and printed, the printed part is moved in the +Z direction by a distance of one layer; the first clamping mechanism and the second clamping mechanism are both fixed clamping mechanisms, which are used to clamp the printed part during the reset process when the middle clamping mechanism moves to the maximum stroke, so as to keep the position of the printed part unchanged;

[0038] The first clamping mechanism includes a first clamping head 2 and a first one-way roller 16; the first clamping head 2 is mounted on the frame 1 to reciprocate in the vertical direction, and the first one-way roller 16 is located at the bottom of the first clamping head 2 and can rotate in one direction;

[0039] The intermediate clamping mechanism can be installed on the frame 1 so as to be reciprocatingly movable in the horizontal direction, and comprises an intermediate clamping head 4 and an intermediate one-way roller 17 which are arranged opposite to each other in the vertical direction; the intermediate clamping head 4 can reciprocate in the vertical direction; the intermediate one-way roller 17 is located at the bottom of the intermediate clamping head 4 and can rotate in one direction;

[0040] The second clamping mechanism includes a second clamping head 6 and a second one-way roller 18; the second clamping head 6 is mounted on the frame 1 so as to be reciprocatingly movable in a vertical direction; the second one-way roller 18 is located at the bottom of the second clamping head 6 and is unidirectionally rotatable;

[0041] The rotation direction of the first one-way roller 16 is the same as that of the second one-way roller 18, and opposite to that of the middle one-way roller 17; the tangent direction of the vertex of the first one-way roller 16 is consistent with the pushing direction of the long truss 19;

[0042] The control mechanism is used to control the actions of each clamping mechanism.

[0043] The specific printing process using the above-mentioned push device is as follows Figure 3a-3d The structure is shown in Figure 1. The specific process is as follows:

[0044] The first step, such as Figure 3aAs shown, the initial truss structure (initial section) is loaded into the pushing device, the middle clamping mechanism clamps the initial section, and the first and second clamping mechanisms are released;

[0045] The second step is, Figure 3b As shown, the print head 15 completes a layer of printing on the -Z end face of the initial section, and the printing thickness is 0.2mm to 0.8mm. The intermediate clamping mechanism moves a layer of distance (0.2mm to 0.8mm) in the +Z direction while clamping the truss, so that the -Z end face of the truss structure is again kept at a reasonable distance from the print head 15. During this printing process, the first and second clamping mechanisms are released, and the bottom surface of the printed truss is supported on the top of the first one-way roller 16 and the second one-way roller 18. The first one-way roller 16 and the second one-way roller 18 rotate in the clockwise direction to reduce the friction force of pushing the truss.

[0046] The third step is Figure 3c As shown, when the intermediate clamping mechanism moves to the end of the +Z direction, that is, the maximum stroke of the intermediate clamping mechanism in the lateral direction, the first and second clamping mechanisms are clamped, and the intermediate clamping mechanism is released;

[0047] The fourth step is Figure 3d As shown, the middle clamping mechanism moves in the -Z direction, returns to the initial position of the middle clamping mechanism, and clamps after resetting, while the first and second clamping mechanisms are released. During the resetting process of the middle clamping mechanism, the first one-way roller 16 and the second one-way roller 18 cannot rotate in the reverse direction (in the counterclockwise direction), ensuring that the printed piece is not driven in the -Z direction by the pushing device during the resetting process of the middle clamping mechanism; while the middle one-way roller 17 can rotate in the counterclockwise direction during the resetting process of the middle clamping mechanism, thereby reducing the friction between the middle one-way roller 17 and the truss and minimizing the impact on the truss.

[0048] Step 5: Repeat steps 1 to 4 in this way to complete the multi-layer printing of the long truss 19.

[0049] The pushing device is used to push the long truss 19 that is continuously printed on the track. During the normal printing of the long truss 19, the middle clamping mechanism clamps the printed long truss 19 and pushes it along the printing direction. The first and second clamping mechanisms are loosened. The printed long truss 19 is supported on the first and second one-way rollers while being clamped by the middle clamping mechanism, and rolls and rubs with the first and second one-way rollers to ensure that the friction of the workpiece is minimized and the movement step is accurate. When the middle clamping mechanism moves from one end to the other end and needs to return to its original position, the first and second clamping mechanisms clamp the printed long truss 19, and the middle The clamping mechanism is released, and the friction force increases because the first and second one-way rollers cannot rotate in the opposite direction. The first and second clamping mechanisms in the clamped state and the long truss 19 are converted into sliding friction, ensuring that the printed workpiece does not move. The middle one-way roller 17 can rotate in the opposite direction, so that the middle one-way roller 17 and the long truss 19 are in a rolling friction state, reducing the friction force, thereby limiting the position change of the printed workpiece during the resetting process of the middle clamping mechanism. This cycle is repeated to complete the push task of printing on the infinitely long truss 19 on track and accurately control the position of the printed workpiece.

[0050] The above-mentioned pushing device is designed for the conversion of rolling friction and sliding friction during the printing process of the extra-long truss. In the process of pushing the long truss out of the printing forming area and the resetting process of the intermediate clamping mechanism, the combination design of the one-way rollers is used to realize the conversion of rolling friction and sliding friction. During the printing process, the printed part and the first and second one-way rollers are in rolling friction, and the printed part can be moved accurately according to the layer thickness; at the same time, in the resetting process of the intermediate clamping mechanism, the first and second one-way rollers are reversely locked to convert the friction into sliding friction with a larger friction coefficient, so that the position of the printed part can be accurately maintained; finally, continuous printing and forming in at least one forming direction is realized, and the forming size is not limited by the envelope space of the equipment, that is, the function of "small equipment" to manufacture "large structure".

[0051] In a specific implementation manner, Figure 1 As shown in the structure, the frame 1 includes four support rods 8 arranged in parallel; the support rods 8 extend laterally and are used to support the intermediate clamping mechanism; the intermediate clamping mechanism also includes a fixed bracket 9 and a transverse driving mechanism 10; the fixed bracket 9 and the four support rods 8 are slidably matched; the transverse driving mechanism 10 is fixedly installed on the frame 1 and is connected to the control mechanism signal to drive the fixed bracket 9 to slide along the support rod 8; the intermediate clamping head 4 and the intermediate one-way roller 17 are both installed on the fixed bracket 9.

[0052] The frame 1 of the above-mentioned pushing device includes four support rods 8 arranged in parallel; the support rods 8 extend laterally and are used to support the intermediate clamping mechanism; the intermediate clamping mechanism also includes a fixed bracket 9 and a transverse driving mechanism 10; the fixed bracket 9 and the four support rods 8 are slidably matched; the transverse driving mechanism 10 is fixedly installed on the frame 1 and is connected to the control mechanism signal to drive the fixed bracket 9 to slide along the support rods 8; the intermediate clamping head 4 and the intermediate unidirectional roller 17 are both installed on the fixed bracket 9; the above-mentioned structure can stably support the intermediate clamping mechanism, ensure the reciprocating movement of the intermediate clamping mechanism along the extension direction of the long truss 19, and realize the stable support of the long truss 19 printed on the track, and the transverse driving mechanism 10 can use a motor screw to drive the fixed bracket 9.

[0053] Furthermore, if Figure 2 As shown, the first clamping head 2, the middle clamping head 4 and the second clamping head 6 all include a clamping motor 11, a linear slide 12, a pressure sensor 13 and a pressure block 14; the clamping motor 11 of the first clamping head 2 and the clamping motor 11 of the second clamping head 6 are both fixedly installed on the top of the frame 1; the clamping motor 11 of the middle clamping head 4 is fixedly installed on the top of the fixed bracket 9; the bottom end of the clamping motor 11 is transmission-connected with the top end of the linear slide 12 to drive the linear slide 12 to reciprocate in the vertical direction; the clamping motor 11 can realize transmission connection with the linear slide 12 through a screw nut pair, thereby converting the rotation of the clamping motor 11 into the rotation of the linear slide The table 12 reciprocates in the vertical direction; the pressure sensor 13 is fixedly installed on the linear slide 12, and is used to detect the pressure between the pressure block 14 and the printed part; when the pressure is 0, it indicates that the pressure block 14 has not yet contacted the printed part. When the pressure reaches a preset pressure value, the control system determines that the pressure block 14 has pressed the printed part according to the pre-stored pressure data; the pressure block 14 is fixedly installed on the bottom end of the linear slide 12, and is used to cooperate with the corresponding one-way roller to clamp the long truss 19; the control system is signal-connected to each clamping motor 11 and each pressure sensor 13, and is used to control the corresponding clamping motor 11 according to the pressure signal of the pressure sensor 13.

[0054] Each clamping head of the above-mentioned pushing device includes a clamping motor 11, a linear slide 12, a pressure sensor 13 and a pressure block 14; each clamping head controls the movement of the linear slide 12 in the vertical direction through the clamping motor 11 to realize the clamping and loosening of the clamping mechanism, and judges the clamping state of the clamping mechanism on the printed workpiece through the pressure sensor 13, so as to realize stable clamping of the printed workpiece, avoid damage to the long truss 19 due to excessive clamping force or unstable clamping due to insufficient clamping force, thereby improving the pushing effect.

[0055] Specifically, Figure 1As shown, the first clamping mechanism, the intermediate clamping mechanism and the second clamping mechanism all include a support plate; the first clamping mechanism is provided with a first support plate 3; the intermediate clamping mechanism is provided with an intermediate support plate 5; the second clamping mechanism is provided with a second support plate 7; the first support plate 3 of the first clamping mechanism and the second support plate 7 of the second clamping mechanism are both fixedly mounted on the frame 1; the first one-way roller 16 and the second one-way roller 18 are both rotatably mounted on the corresponding support plates through one-way bearings; the intermediate support plate 5 of the intermediate clamping mechanism is fixedly mounted on the fixed bracket 9; the intermediate one-way roller 17 is rotatably mounted on the intermediate support plate 5 of the intermediate clamping mechanism through a one-way bearing.

[0056] On the basis of the various embodiments described above, the first clamping mechanism, the middle clamping mechanism and the second clamping mechanism all include three one-way rollers distributed in a triangle, that is, each clamping mechanism is provided with two rows of one-way rollers along the horizontal direction, wherein, along the pushing direction of the long truss, the first row is provided with a one-way roller, and the second row is provided with two coaxial one-way rollers; and along the arrangement direction of the two one-way rollers in the second row, the one-way roller in the first row is located in the middle of the two one-way rollers in the second row; the rotation axes of the first one-way roller 16, the second one-way roller 18 and the middle one-way roller 17 are arranged perpendicular to both the horizontal and vertical directions.

[0057] Each clamping mechanism of the above-mentioned pushing device includes three one-way rollers distributed in a triangle. The three one-way rollers can increase the contact area with the long truss 19 and provide stable support. At the same time, the one-way rollers can guide the pushing direction of the truss so that the truss is always pushed along the predetermined track.

[0058] In summary, the above are only preferred embodiments of the present invention and are not intended to limit the protection scope of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A pushing device for continuous printing of long trusses on track, characterized in that: It comprises a frame, a control mechanism, and a first clamping mechanism, an intermediate clamping mechanism, and a second clamping mechanism sequentially distributed in the transverse direction; The first clamping mechanism comprises a first clamping head and a first one-way roller; the first clamping head is mounted on the frame to reciprocate along a vertical direction, and the first one-way roller is located at the bottom of the first clamping head and can rotate in one direction; The intermediate clamping mechanism is installed on the frame so as to be reciprocatingly movable in the lateral direction, and comprises an intermediate clamping head and an intermediate unidirectional roller arranged opposite to each other in the vertical direction; the intermediate clamping head is reciprocatingly movable in the vertical direction; the intermediate unidirectional roller is located at the bottom of the intermediate clamping head and is unidirectionally rotatable; The second clamping mechanism comprises a second clamping head and a second one-way roller; the second clamping head is mounted on the frame so as to be reciprocatingly movable in a vertical direction; the second one-way roller is located at the bottom of the second clamping head and is unidirectionally rotatable; The rotation direction of the first one-way roller is the same as that of the second one-way roller, and opposite to that of the middle one-way roller; the movement tangent direction of the vertex of the first one-way roller is consistent with the pushing direction of the long truss; The control mechanism is used to control the actions of each clamping mechanism; The frame includes four support rods arranged in parallel; The support rod extends in the transverse direction and is used to support the intermediate clamping mechanism; The intermediate clamping mechanism also includes a fixed bracket and a transverse driving mechanism; the fixed bracket is slidably matched with the four support rods; the transverse driving mechanism is fixedly installed on the frame and is connected to the control mechanism by signal, so as to drive the fixed bracket to slide along the support rods; The intermediate clamping head and the intermediate one-way roller are both mounted on the fixed bracket; The first clamping head, the intermediate clamping head and the second clamping head all include a clamping motor, a linear slide, a pressure sensor and a pressure block; The clamping motor of the first clamping head and the clamping motor of the second clamping head are both fixedly mounted on the top of the frame; the clamping motor of the middle clamping head is fixedly mounted on the top of the fixed bracket; The bottom end of the clamping motor is transmission-connected to the top end of the linear slide, and is used to drive the linear slide to reciprocate in the vertical direction; The pressure sensor is fixedly mounted on the linear slide and is used to detect the pressure between the pressing block and the printed part; The pressing block is fixedly mounted on the bottom end of the linear slide, and is used to cooperate with the corresponding one-way roller to clamp the long truss; The control mechanism is signal-connected to each clamping motor and each pressure sensor, and is used to control the corresponding clamping motor according to the pressure signal of the pressure sensor.

2. The pushing device according to claim 1, characterized in that: The first clamping mechanism, the intermediate clamping mechanism and the second clamping mechanism all include a support plate; The support plate of the first clamping mechanism and the support plate of the second clamping mechanism are both fixedly mounted on the frame; the first one-way roller and the second one-way roller are both rotatably mounted on the corresponding support plate through a one-way bearing; The support plate of the intermediate clamping mechanism is fixedly mounted on the fixed bracket; the intermediate one-way roller is rotatably mounted on the support plate of the intermediate clamping head via a one-way bearing.

3. The pushing device according to claim 1 or 2, characterized in that: The first clamping mechanism, the middle clamping mechanism and the second clamping mechanism each include three unidirectional rollers distributed in a triangle; The rotation axes of the first one-way roller, the second one-way roller and the middle one-way roller are arranged perpendicular to both the horizontal and vertical directions.

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