An expanded body tensioning structure suitable for automobile assembly line

Abstract

The application discloses an expansion type vehicle body tensioning structure suitable for a vehicle assembling production line, which comprises a vehicle body provided with clamping holes in the bottom, an execution clamping structure, a movable handle, a cable and a pedal tensioning structure; the execution clamping structure is used for cooperating with the clamping holes of the vehicle body to realize preliminary clamping positioning of the vehicle body; the movable handle is linked with the execution clamping structure and is used for controlling the execution clamping structure to switch to a contraction state facilitating insertion into the clamping holes of the vehicle body or to switch to an expansion state clamping the vehicle body; one end of the cable is connected with the execution clamping structure, and the other end is connected with the pedal tensioning structure and is used for transmitting the acting force of the pedal tensioning structure; the pedal tensioning structure is fixed on the ground and, through the stepping operation of an operator, downward pulling force is applied to the execution clamping structure through the cable to offset upward thrust force generated on the vehicle body when a lifting machine lifts the chassis, so that the assembling position of the vehicle body is maintained stable.

Description

Technical Field

[0001] This invention relates to the field of automotive assembly technology, and more particularly to an expanded body tensioning structure suitable for automotive assembly production lines. Background Technology

[0002] In the automotive chassis assembly production line, the precise docking of the car body and the chassis is a key process. During the assembly process, the car body is transported to the assembly station by a lifting device. At the assembly station, the lifting machine lifts the chassis so that the chassis and the connecting parts at the bottom of the car body are docked.

[0003] However, during the assembly process, the car body shifts upward due to the pushing action of the springs on the upper chassis, thus deviating from the preset assembly position and causing assembly errors.

[0004] Based on this, an expansion-type body tensioning structure suitable for automobile assembly production lines is proposed. This structure is used to tension the body during the body assembly process, effectively preventing the body from shifting upward and improving assembly accuracy. Summary of the Invention

[0005] To address the aforementioned problems, this invention provides an expanded body tensioning structure suitable for automobile assembly lines.

[0006] To achieve the above objectives, this application provides the following technical solution:

[0007] An expanded body tensioning structure suitable for automobile assembly lines includes a body with a locking hole at the bottom, an actuator locking structure, a movable handle, a cable, and a pedal tensioning structure.

[0008] The actuator locking structure is used to cooperate with the locking holes of the vehicle body to achieve the initial locking and positioning of the vehicle body; the movable handle is linked with the actuator locking structure to control the actuator locking structure to switch to a retracted state that facilitates insertion into the locking holes of the vehicle body, or to an expanded state that locks the vehicle body.

[0009] One end of the cable is connected to the actuator mechanism, and the other end is connected to the pedal tensioning mechanism to transmit the force of the pedal tensioning mechanism.

[0010] The pedal tensioning structure is fixed to the ground. When the operator steps on it, a downward pulling force is applied to the actuator locking structure via a cable to counteract the upward thrust generated on the vehicle body when the lifting machine raises the chassis, thus maintaining the stability of the vehicle body's assembled position.

[0011] The further configuration is as follows: the actuator includes a sleeve and an expansion tension pin, the lower part of the expansion tension pin is inserted into the sleeve, and the upper part can pass through the locking hole of the vehicle body and achieve a tight fit with the locking hole through radial expansion.

[0012] Further configuration includes a center pin, wherein the expansion tensioning pin is a hollow cylindrical structure with 3-5 elastic opening slots distributed axially along its sidewalls and top, and at least one set of retaining springs sleeved on its circumferential surface. The retaining springs are used to provide radial tightening force to the expansion tensioning pin. The center pin is slidably disposed inside the expansion tensioning pin. A connecting platform is provided on the circumferential surface of the center pin near its bottom. A lifting spring in a compressed state is provided between the lower surface of the connecting platform and the inner bottom wall of the sleeve. The lifting spring provides an upward axial pushing force to the center pin.

[0013] The sleeve is further configured such that: a tapered sleeve is provided on the side of the sleeve near its bottom; two parallel connecting blocks are provided at the bottom of the central pin; and a pin is provided between the two connecting blocks; the movable handle is bent and a relief groove is provided on the side of the tapered sleeve for the movable handle to pass through; the movable handle is hinged to the tapered sleeve through the relief groove, and the inner side of the movable handle passes through the relief groove and is slidably connected to the pin.

[0014] The pedal tensioning structure is further configured as follows: a base, a linkage rod, a tensioning rod, and a foot pedal. The linkage rod is hinged to the base, one end of which is connected to a cable, and the other end is connected to the tensioning rod via a hinge shaft. The other end of the tensioning rod is connected to the foot pedal. A compression spring is also provided on the base, and the top end of the compression spring is connected to the linkage rod to provide an upward restoring force to the linkage rod.

[0015] The further configuration includes a vertical plate with a long groove and a short groove communicating with the long groove. The short groove is located on the bottom side of the long groove, and the tensioning rod can slide along the long groove and be inserted into the short groove to achieve tensioning and locking of the cable.

[0016] A further feature is provided: the circumferential surface of the expansion tensioning pin is provided with a slot, which is adapted to the edge of the slot hole in the vehicle body floor to enhance the clamping effect on the vehicle body.

[0017] The expansion tensioning pin is further configured such that: a mounting boss is provided on the circumferential surface of the expansion tensioning pin, the expansion tensioning pin is mounted on the top of the sleeve through the mounting boss, and its lower part is inserted into the sleeve; a conical platform is provided on the circumferential surface of the sleeve near its top, a clamping cap is fastened on the mounting boss, and a bolt for fixing the clamping cap, the sleeve and the expansion tensioning pin is provided on the side of the clamping cap.

[0018] A further configuration is provided: a U-shaped block is provided on the upper surface of the base, a hinge shaft is horizontally placed inside the U-shaped block, and the linkage rod is hinged to the U-shaped block through the hinge shaft.

[0019] A further feature is provided: a trapezoidal limiting block is provided between the short groove and the long groove.

[0020] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0021] This invention effectively counteracts the upward thrust generated when the chassis is raised by the radial expansion of the tensioning pin and its tight fit with the body locking hole, combined with the continuous downward pulling force provided by the pedal tensioning mechanism. This ensures the stability of the vehicle body position during assembly and greatly improves the assembly accuracy of the chassis and body. Furthermore, the entire tensioning and releasing process is completed through the movable handle and foot pedal. The movable handle controls the contraction and expansion of the tensioning pin, and the foot pedal controls the tensioning and locking of the cable. The operation is labor-saving and efficient, reducing the labor intensity of the operators.

[0022] This invention can adapt to the size differences of the body clip holes of different car models; the pedal tensioning structure is fixed to the ground by bolts, and the installation position can be adjusted according to the needs of the assembly station. There is no need to design a special tensioning device for a specific car model, which reduces the investment in customized production line equipment and lowers the production and maintenance costs of car companies. Attached Figure Description

[0023] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0025] Figure 2 This is a cross-sectional view of the internal structure of the sleeve of the present invention;

[0026] Figure 3 for Figure 2 Partial structural diagram;

[0027] Figure 4 for Figure 3 A schematic diagram of the top structure;

[0028] Figure 5 for Figure 3 A schematic diagram of the central structure;

[0029] Figure 6 for Figure 3 A schematic diagram of the bottom structure;

[0030] Figure 7 This is a schematic diagram of the pedal tensioning structure of the present invention;

[0031] Figure 8 This is a schematic diagram of the expansion tensioning pin of the present invention.

[0032] Reference numerals: 1. Body; 2. Snap-hole; 3. Movable handle; 4. Sleeve; 5. Expansion tension pin; 6. Erecting boss; 7. Conical platform; 8. Clamping cap; 9. Elastic opening slot; 10. Groove; 11. Snap spring; 12. Snap groove; 13. Lifting spring; 14. Center pin; 15. Connecting platform; 16. Conical sleeve; 17. Connecting block; 18. Pin shaft; 19. Clearance groove; 20. Slide groove; 21. Base; 22. U-shaped block; 23. Hinge shaft; 24. Vertical plate; 25. Long groove; 26. Short groove; 27. Trapezoidal limit block; 28. Linkage rod; 29. ​​Tensioning rod; 30. Foot pedal; 31. Cable; 32. Handle. Detailed Implementation

[0033] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0035] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances. Example

[0036] Reference Figures 1-8 The present invention discloses an expansion-type body tensioning structure suitable for automobile assembly production line, comprising a body 1 with a locking hole 2 at the bottom, an execution locking structure, a movable handle 3, a cable 31, and a pedal tensioning structure.

[0037] The actuator includes a sleeve 4, in which an expansion tension pin 5 is fitted. Specifically, an erection boss 6 is provided on the circumferential surface of the expansion tension pin 5. The expansion tension pin 5 is supported on the top of the sleeve 4 through the erection boss 6, and its lower part is inserted into the sleeve 4.

[0038] A conical platform 7 is provided on the circumferential surface of the sleeve 4 near its top. A clamping cap 8 is fastened on the erected protrusion 6. A bolt is provided on the side of the clamping cap 8 to fix the clamping cap 8, the sleeve 4 and the expansion tensioning pin 5 together.

[0039] In this embodiment, the expansion tensioning pin 5 is a hollow cylindrical structure with 3-5 elastic opening slots 9 evenly distributed along the axial direction on the side wall and top, giving it the elastic deformation ability to contract and expand radially. A groove 10 is provided on the circumferential surface of the expansion tensioning pin 5, and a retaining spring 11 is sleeved in the groove 10. The retaining spring 11 provides an inward radial tightening force to the expansion tensioning pin 5. When there is no external force, the retaining spring 11 tightens the expansion tensioning pin 5, so that the expansion tensioning pin 5 is in a contracted state to facilitate insertion into the retaining hole 2 of the vehicle body 1.

[0040] Furthermore, the combination of groove 10 and snap ring 11 is provided in three sets, located at the top, middle and bottom of expansion tension pin 5 respectively; and the expansion tension pin 5 is provided with a chamfer to facilitate its passage through the locking hole 2 of the body 1 in the tightened state. On the lower side of the chamfer, there is a locking groove 12 opened on the circumferential surface of the expansion tension pin 5. The locking groove 12 is adapted to the bottom plate of the body 1. When the expansion tension pin 5 is inserted into the locking hole 2, the inner wall of the elastic opening slit 9 is forced to open outward, causing the expansion tension pin 5 to expand radially as a whole, so that its outer wall is tightly fitted with the inner wall of the locking hole 2 of the body 1. At the same time, the locking groove 12 fits more tightly with the bottom plate of the body 1, so as to achieve reliable locking of the body 1.

[0041] In this embodiment, the external force for the radial expansion of the expansion tension pin 5 is provided by the lifting spring 13 and the center pin 14 in the actuator mechanism. Specifically, the center pin 14 is slidably disposed inside the expansion tension pin 5, and its top is tapered. A connecting platform 15 is provided on the circumferential surface of the center pin 14 near its bottom. The lifting spring 13 is arranged around the center pin 14, and its top is fixedly connected to the lower surface of the connecting platform 15. Its bottom is fixedly connected to the inner bottom wall of the sleeve 4. The lifting spring 13 is in a compressed state, and its elastic potential energy provides an upward axial thrust to the center pin 14.

[0042] Specifically, when the upward thrust of the lifting spring 13 pushes the center pin 14 upward, the conical top of the center pin 14 will gradually push against the inner wall of the expansion tension pin 5. Since the 3-5 elastic openings 9 on the side wall of the expansion tension pin 5 have radial deformation capability, after the expansion tension pin 5 is subjected to radial compression by the conical structure, the elastic openings 9 will open outward, causing the overall diameter of the expansion tension pin 5 to expand, thus achieving radial expansion.

[0043] A tapered sleeve 16 is provided on the side of the sleeve 4 near its bottom, and two parallel connecting blocks 17 are provided at the bottom of the central pin 14, with a pin 18 provided between the two connecting blocks 17.

[0044] In this embodiment, the movable handle 3 is bent, and a relief groove 19 is provided on the side of the conical sleeve 16 for the movable handle 3 to pass through. The movable handle 3 is hinged to the conical sleeve 16 through the relief groove 19, and the inner side of the movable handle 3 passes through the relief groove 19 and is connected to the pin 18. Specifically, a sliding groove 20 is provided on the inner side of the movable handle 3, and the pin 18 slides in cooperation with the sliding groove 20.

[0045] Under normal conditions, the elastic potential energy of the lifting spring 13 pushes the center pin 14 upward. Under the pushing force of the lifting spring 13, the center pin 14 is in a high position inside the sleeve 4. The conical structure at its top will continuously push the inner wall of the expansion tension pin 5, so that the expansion tension pin 5 maintains radial expansion deformation.

[0046] When the expansion tension pin 5 is inserted into the vehicle body 1, the pushing force of the lifting spring 13 is countered by operating the movable handle 3, causing the expansion tension pin 5 to switch from the "normal expansion" state to the "retracted and ready for insertion" state. The specific operation and structural linkage logic is as follows:

[0047] When the operator moves the bent movable handle 3 inward, the movable handle 3 is hinged to the conical sleeve 16 and slides with the pin 18 at the bottom of the center pin 14 through the sliding groove 20. When the movable handle 3 rotates around the hinge point, the sliding groove 20 on its inner side drives the pin 18 to move downward, thereby pulling the center pin 14 to overcome the upward pushing force of the lifting spring 13 and slide downward along the inner wall of the sleeve 4. After the center pin 14 moves downward, the conical structure at its top will gradually disengage from the pushing force on the inner wall of the expansion tensioning pin 5. At this time, the 3-5 elastic opening slots 9 on the side wall of the expansion tensioning pin 5 lose the radial compression force. Under the action of the inward radial tightening force of the three sets of retaining springs 11, the elastic opening slots 9 contract inward, causing the overall diameter of the expansion tensioning pin 5 to shrink and return to the "contracted state".

[0048] At this time, the diameter of the expansion tension pin 5 is smaller than the diameter of the body 1 locking hole 2, which meets the insertion conditions. After the expansion tension pin 5 is inserted into the body 1 locking hole 2, the movable handle 3 is released. The center pin 14 moves upward under the return force of the lifting spring 13. The conical structure at its top pushes the inner wall of the expansion tension pin 5 again. The elastic opening slit 9 opens outward under the radial compression, which drives the overall diameter of the expansion tension pin 5 to expand. At this time, the outer wall of the expansion tension pin 5 is tightly fitted with the inner wall of the body 1 locking hole 2, forming a radial fixation of "surface contact". In addition, the groove 12 on the circumferential surface of the expansion tension pin 5 engages with the edge of the body 1 bottom plate locking hole 2, realizing the reliable locking of the body 1.

[0049] In this embodiment, one end of the cable 31 is fixedly connected to the bottom of the conical sleeve 16, and the other end is connected to the pedal tensioning structure fixed on the ground.

[0050] Specifically, the pedal tensioning structure includes a base 21 that is bolted to the ground, a U-shaped block 22 on the upper surface of the base 21, a hinge shaft 23 horizontally placed inside the U-shaped block 22, a vertical plate 24 installed on the side of the base 21 away from the hinge shaft 23, a long groove 25 vertically opened on the vertical plate 24, a short groove 26 communicating with the lower side of the long groove 25, and a trapezoidal limiting block 27 between the short groove 26 and the long groove 25.

[0051] The pedal tensioning structure also includes a linkage rod 28 hinged to the hinge shaft 23 and a tensioning rod 29 hinged to the linkage rod 28 via a hinge shaft. The tensioning rod 29 is slidably connected to the long slot 25 and the short slot 26. One end of the tensioning rod 29 passes through the vertical plate 24 and is provided with a foot pedal 30. A vertically arranged compression spring is installed on the base 21, and the top end of the compression spring is connected to the linkage rod 28.

[0052] Under normal conditions, the compression spring pushes the linkage rod 28, and the tension rod 29, which is connected to the linkage rod 28 via a hinge shaft, is locked at the top of the long slot 25. In this state, the linkage rod 28 is in a high position. When the expansion tension pin 5 is inserted into the locking hole 2, the cable 31 is in a slack state. The slack design provides space for the expansion tension pin 5 to be inserted into the locking hole 2 of the vehicle body 1, ensuring that the expansion tension pin 5 can be smoothly aligned with the locking hole 2 and completed.

[0053] When the expansion tension pin 5 is inserted into the vehicle body 1, the foot pedal 30 is pressed down. The downward force applied causes the tension rod 29 to slide vertically downward along the long groove 25 of the vertical plate 24. At this time, the tension rod 29 disengages from the initial position at the top of the long groove 25, overcomes the upward pushing force of the compression spring on the linkage rod 28, and pulls the linkage rod 28 to rotate downward around the hinge shaft 23 in the U-shaped block 22. As a result, the cable 31 connected to the linkage rod 28 is gradually tightened. When the tension rod 29 slides along the long groove 25 to the lower part where it connects with the short groove 26, the operator can slightly push the foot pedal 30 laterally to make the tension rod 29 engage in the short groove 26. The top wall of the short groove 26 restricts the tension rod 29 to return to its upward position. At this time, the linkage rod 28 is in a low position.

[0054] Since the cable 31 is already in a tightened state under the locking of the pedal tensioning structure, one end of the cable 31 is fixed to the conical sleeve 16, and the other end is pulled down by the low-position locking of the linkage rod 28, and then transmitted to the vehicle body 1 through the sleeve 4 and the expansion tensioning pin 5. The slot 12 of the expansion tensioning pin 5 engages with the bottom plate of the vehicle body 1.

[0055] Therefore, when the lifting machine lifts the chassis, the cable 31 will provide a downward pulling force to the vehicle body 1 to prevent the vehicle body 1 from being pushed upward by the chassis and deviating from the assembly position, thus ensuring the stability of the vehicle body 1's posture during the assembly process.

[0056] Furthermore, a handle 32 is provided on the sleeve 4 to facilitate convenient operation by staff.

[0057] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An expanded body tensioning structure suitable for automobile assembly lines, characterized in that, The vehicle body (1) includes a locking hole (2) at the bottom, an actuator locking structure, a movable handle (3), a cable (31), and a pedal tensioning structure; The actuator locking structure is used to cooperate with the locking hole (2) of the vehicle body (1) to achieve the initial locking and positioning of the vehicle body (1); the actuator locking structure includes an expansion tension pin (5) and a center pin (14). The upper part of the expansion tension pin (5) can pass through the locking hole (2) of the vehicle body (1) and achieve a tight fit with the locking hole (2) through radial expansion. The center pin (14) is set inside the expansion tension pin (5). When the center pin (14) moves upward, the expansion tension pin (5) expands, and when it moves downward, the expansion tension pin (5) retracts. The movable handle (3) is connected to the center pin (14) and is used to drive the center pin (14) to move upward and downward. One end of the cable (31) is connected to the actuator mechanism, and the other end is connected to the pedal tensioning mechanism to transmit the force of the pedal tensioning mechanism. The pedal tensioning structure is fixed on the ground. When the operator steps on it, the cable (31) applies a downward pulling force to the actuator clamping structure to counteract the upward pushing force on the vehicle body (1) when the lifting machine lifts the chassis, thus maintaining the stability of the assembled position of the vehicle body (1).

2. The expanded body tensioning structure suitable for automobile assembly lines according to claim 1, characterized in that, The execution clamping structure also includes a sleeve (4) in which the lower part of the expansion tensioning pin (5) is inserted.

3. The expanded body tensioning structure suitable for automobile assembly lines according to claim 2, characterized in that, The expansion tensioning pin (5) is a hollow cylindrical structure with 3-5 elastic opening slots (9) distributed axially on its side wall and top. At least one set of retaining springs (11) is sleeved on its circumferential surface. The retaining springs (11) are used to provide radial tightening force to the expansion tensioning pin (5). The center pin (14) is slidably disposed inside the expansion tensioning pin (5). A connecting platform (15) is provided on the circumferential surface of the center pin (14) near its bottom. A lifting spring (13) in a compressed state is provided between the lower surface of the connecting platform (15) and the inner bottom wall of the sleeve (4). The lifting spring (13) provides an upward axial pushing force to the center pin (14).

4. The expanded body tensioning structure suitable for automobile assembly lines according to claim 3, characterized in that, The sleeve (4) has a tapered sleeve (16) on one side near its bottom. Two parallel connecting blocks (17) are provided at the bottom of the central pin (14), and a pin (18) is provided between the two connecting blocks (17). The movable handle (3) is bent. A relief groove (19) is provided on the side of the tapered sleeve (16) for the movable handle (3) to pass through. The movable handle (3) is hinged to the tapered sleeve (16) through the relief groove (19), and the inner side of the movable handle (3) slides through the relief groove (19) and is slidably connected to the pin (18).

5. An expanded body tensioning structure suitable for automobile assembly lines according to claim 1, characterized in that, The pedal tensioning structure includes a base (21), a linkage rod (28), a tensioning rod (29), and a foot pedal (30). The linkage rod (28) is hinged to the base (21), with one end connected to the cable (31) and the other end connected to the tensioning rod (29) via a hinge shaft. The other end of the tensioning rod (29) is connected to the foot pedal (30). A compression spring is also provided on the base (21), with the top end of the compression spring connected to the linkage rod (28) to provide an upward restoring force to the linkage rod (28).

6. An expanded body tensioning structure suitable for automobile assembly lines according to claim 5, characterized in that, The pedal tensioning structure also includes a vertical plate (24), on which a long groove (25) and a short groove (26) communicating with the long groove (25) are provided. The short groove (26) is located on the bottom side of the long groove (25). The tensioning rod (29) can slide along the long groove (25) and be inserted into the short groove (26) to achieve tensioning and locking of the cable (31).

7. An expanded body tensioning structure suitable for automobile assembly lines according to claim 2, characterized in that, The expansion tensioning pin (5) has a slot (12) on its circumferential surface. The slot (12) is adapted to the edge of the slot (2) on the bottom plate of the vehicle body (1) to enhance the clamping effect on the vehicle body (1).

8. An expanded body tensioning structure suitable for automobile assembly lines according to claim 3, characterized in that, The expansion tension pin (5) has a mounting boss (6) on its circumferential surface. The expansion tension pin (5) is mounted on the top of the sleeve (4) through the mounting boss (6), and its lower part is inserted into the sleeve (4). A conical platform (7) is provided on the circumferential surface of the sleeve (4) near its top. A clamping cap (8) is fastened on the mounting boss (6). A bolt is provided on the side of the clamping cap (8) to fix the clamping cap (8), the sleeve (4) and the expansion tension pin (5).

9. An expanded body tensioning structure suitable for automobile assembly lines according to claim 5, characterized in that, A U-shaped block (22) is provided on the upper surface of the base (21). A hinge shaft (23) is horizontally placed inside the U-shaped block (22). The linkage rod (28) is hinged to the U-shaped block (22) through the hinge shaft (23).

10. An expanded body tensioning structure suitable for automobile assembly lines according to claim 6, characterized in that, A trapezoidal limiting block (27) is provided between the short groove (26) and the long groove (25).

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