Expansion rod

Abstract

An expansion rod comprises a sleeve assembly, an air expansion assembly and a plurality of expansion assemblies, the sleeve assembly comprises a main pipe, the main pipe is provided with a first inner hole penetrating along the axis of the main pipe, the air expansion assembly comprises an air bag pipe, the air bag pipe is arranged in the first inner hole, and the hole wall of the first inner hole is provided with a plurality of operation hole sets corresponding to the expansion assemblies in a one-to-one mode around the air bag pipe. The operation hole set comprises a key hole and a plurality of reset holes, the key hole penetrates to the outer side wall of the main pipe, the expansion assembly comprises an expansion key, an expansion plate and a plurality of reset springs, the expansion key is arranged in the key hole, the expansion plate is arranged in the first inner hole, and the two opposite end faces of the expansion plate are connected to the expansion key and the air bag pipe correspondingly. The two ends of the reset spring are connected to the reset hole and the expansion plates correspondingly, and when the air bag pipe expands, the air bag pipe extrudes the expansion plates, so that the expansion keys move in the direction away from the first inner hole. The reset spring of the expansion rod can push the expansion key and the expansion plate to reset the expansion key and the expansion plate, and the expansion key is prevented from being clamped.

Description

Technical Field

[0001] The utility model relates to the technical field of material transportation devices, in particular to an expansion rod. Background Art

[0002] At present, the fork-picking device generally uses an expansion rod to connect the coil, which is connected by an air pump, an air bag and an expansion key. Specifically, after the expansion rod is inserted into the through hole of the coil, the air pump inflates the air bag inside the rod to expand the air bag, and the air bag squeezes multiple expansion keys evenly distributed on the rod in a circumferential direction, stretching each expansion key. Each expansion key squeezes the hole wall of the through hole of the coil, and prevents the coil from moving along the circumference of the expansion rod through friction. The greater the weight of the coil, the greater the friction required to prevent the coil from moving, and the expansion key is required to apply a greater squeezing force to the coil. When the weight of the coil is too heavy, the squeezing force is too great. Even if the gas in the air bag is released, the expansion key is easy to get stuck and difficult to reset, affecting the removal of the coil and the next use of the expansion rod. Utility Model Content

[0003] The utility model aims to provide an expansion rod to solve the technical problem that the expansion key of the expansion rod is easily stuck when the coiled material is too heavy.

[0004] 20. The repairing kit for automotive dents, according to claim 19, wherein a bottom of the foot stand comprises a through-hole, and the two foot pieces comprise two bosses, wherein the bosses comprise a through-hole, a screw bolt, and a nut. The through-hole comprises a first end, and a second end, wherein the bosses comprise a through-hole, a second end, and a second end, respectively. The bosses comprise a through-hole, a second end, and a second end, wherein the bosses comprise a through-hole, a screw bolt, and a nut.

[0005] Optionally, the inflatable component also includes an inflation head and a plug, the plug, the airbag tube and the inflation head are arranged in sequence from front to back, the inflation head is arranged in the first inner hole, the plug is fixed to the first inner hole, the inflation head is provided with an inflation port that passes through in the front-to-back direction, one end of the tube hole of the airbag tube is connected to the inflation port, the inflation port is used to connect to the air pump, and the plug blocks the other end of the tube hole of the airbag tube.

[0006] Optionally, the sleeve assembly further includes an extension tube, wherein the extension tube is provided with a second inner hole passing through along its axis, and the extension tube is fixedly sleeved on the outside of the main tube and protrudes from the front of the main tube.

[0007] Optionally, a first limiting component is further included, which includes a limiting pin and a first driver. The outer wall of the extension tube is provided with a limiting hole that passes through the second inner hole. The first driver is fixed to the second inner hole, and the limiting pin is provided in the limiting hole. The first driver is connected to the limiting pin, and the first driver can drive the limiting pin to move in a direction away from the second inner hole until it protrudes from the outer wall of the extension tube.

[0008] Optionally, it also includes an anti-collision component, which includes an anti-collision block, a pressure sensor and multiple anti-collision units. The anti-collision block is arranged in front of the extension tube, and the anti-collision block is provided with multiple first connecting holes arranged around the axis of the anti-collision block. The first connecting hole passes through in the front-to-back direction, and the inner ring of the first connecting hole is provided with a mounting boss. The front of the extension tube is provided with multiple second connecting holes corresponding to the first connecting holes one by one, and the second connecting holes are provided with threads. The anti-collision unit corresponds to the first connecting hole and the second connecting hole one by one. The anti-collision unit includes an anti-collision spring and a connecting screw, the connecting screw passes through the first connecting hole, the connecting screw is inserted into the second connecting hole, the connecting screw is threadedly connected to the second connecting hole, the back of the screw head of the connecting screw abuts against the front of the mounting boss, the anti-collision spring is sleeved on the outside of the connecting screw, one end of the anti-collision spring abuts against the front of the extension tube, and the other end abuts against the back of the mounting boss. The pressure sensor is fixed to the second inner hole, the pressure sensor faces the anti-collision block, and the pressure sensor is used to detect the pressure applied to the anti-collision block.

[0009] Optionally, the inflatable component also includes a wiring tube, which is arranged in the first inner hole, the inflation head is provided with a first wiring hole that passes through the front-to-back direction, and the plug is provided with a second wiring hole that passes through the front-to-back direction, and the two ends of the wiring tube are respectively connected to the first wiring hole and the second wiring hole.

[0010] Optionally, the outer wall of the plug is provided with an external thread, the first inner hole is provided with an internal thread, the plug is threadedly connected to the first inner hole, the outer wall of the main pipe is provided with an external thread, the second inner hole is provided with an internal thread, and the main pipe is threadedly connected to the second inner hole.

[0011] Optionally, it also includes multiple wheel assemblies, which are evenly distributed along the circumference of the extension tube. The wheel assembly includes a pulley and a wheel frame. The outer wall of the extension tube is provided with multiple wheel holes that penetrate the second inner hole. The wheel holes correspond one-to-one to the wheel assemblies. The wheel frame is fixed to the second inner hole, and the pulley is provided in the wheel hole. The pulley is rotatably connected to the wheel frame, and the wheel surface of the pulley protrudes from the outer side surface of the extension tube.

[0012] Optionally, the expansion assembly further includes a plurality of reset pins corresponding to the reset holes one by one, the reset holes penetrate the outer wall of the main pipe, the reset pins are fixed in the reset holes, and one end of the reset spring is connected to the reset pins.

[0013] Optionally, a second limit assembly is further included, which is arranged behind the air expansion assembly and the tightening assembly. The second limit assembly includes a clamp, a limit block and a distance sensor. The limit block is a semi-annular block, and the clamp is a semi-annular clamp. The limit block is fixedly connected to the clamp. The limit block and the clamp form a clamping hole adapted to the outer wall of the main pipe. The main pipe passes through the clamping hole, and the limit block and the clamp are clamped to the main pipe. A mounting hole is provided in front of the limit block, and the distance sensor is fixedly arranged in the mounting hole, and the distance sensor faces forward.

[0014] Compared with the prior art, the expansion rod of the embodiment of the utility model has the following beneficial effects:

[0015] The cam is secured to the first and second cams and is adapted to engage the first and second cams when the cam is inflated, so that the cam is secured to the first and second cams and is adapted to engage the first and second cams when the cam is inflated. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a structural diagram of the expansion rod of the utility model.

[0017] Figure 2 This is the front view of the expansion rod of the utility model.

[0018] Figure 3 This is an exploded view of the expansion rod of the utility model.

[0019] Figure 4 for Figure 3 A partial enlarged view of part A in the middle.

[0020] Figure 5 This is a schematic diagram of the structure of the gas expansion component of the present invention (ignoring the wiring tube).

[0021] Figure 6 This is a schematic diagram of the structure of the expansion installation with coiled material of the utility model.

[0022] 1. The camshaft assembly includes the following components: 1. The camshaft assembly includes the following components: 1. The camshaft assembly includes the following components: 1. The camshaft assembly includes the following components: 1. The camshaft assembly includes the following components: 1. The camshaft assembly includes the following components: 1. The camshaft assembly includes the following components: 1. The camshaft assembly includes the following components: 1. The camshaft assembly includes the following components: 1. The camshaft assembly includes the following components: 1. The camshaft assembly includes the following components: 1. The camshaft assembly includes the following components: 1. The camshaft assembly includes the following components: 1. The camshaft assembly includes the following components: 1. The camshaft assembly includes the following components: DETAILED DESCRIPTION

[0023] The following embodiments are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0024] In the description of the present invention, it should be understood that the terms "top", "bottom", "inside", "outside", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present invention.

[0025] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature specified as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of this utility model, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0026] like Figures 1 to 5 As shown, an expansion rod of the present invention includes a sleeve assembly 1, an air expansion assembly 2 and a plurality of expansion assemblies 3, wherein the sleeve assembly 1 includes a main pipe 11, the main pipe 11 is provided with a first inner hole extending along its axis, the air expansion assembly 2 includes an air bag tube 21, the air bag tube 21 is provided in the first inner hole, and the hole wall of the first inner hole is provided with a plurality of operation holes 111 corresponding to the expansion assembly 3 one by one around the air bag tube 21, the operation hole group 111 includes a key hole 1111 and a plurality of reset holes 1112, the key hole 1111 passes through the outer wall of the main pipe 11 Side wall, the tightening assembly 3 includes an expansion key 31, an expansion plate 32 and a plurality of reset springs 33, the expansion key 31 is arranged in the key hole 1111, the expansion plate 32 is arranged in the first inner hole, the two opposite end faces of the expansion plate 32 are respectively connected to the expansion key 31 and relative to the airbag tube 21, the two ends of the reset spring 33 are respectively connected to the reset hole 1112 and the expansion plate 32, when the airbag tube 21 expands, the airbag tube 21 squeezes each of the expansion plates 32, so that each of the expansion keys 31 moves in the direction away from the first inner hole.

[0027] Based on the above technical solution, multiple expansion components 3 are evenly distributed around the airbag tube 21, so that when the airbag tube 21 expands, the airbag tube 21 can evenly squeeze each expansion component 3. Furthermore, when the airbag tube 21 expands, the airbag tube 21 squeezes the expansion plate 32, causing the expansion key 31 to move in the direction away from the first inner hole until the expansion key 31 squeezes the coil 8 sleeved on the outside of the main pipe 11, providing friction for it. The expansion plate 32 can abut against the outer wall of the first inner hole to prevent the expansion key 31 from falling out of the key hole 1111. Furthermore, the two ends of the reset spring 33 are respectively connected to the expansion plate 32 and the reset hole 1112 of the working hole group 111 to provide a force to the expansion plate 32 toward the axis of the main pipe 11. When the airbag shrinks and the airbag does not provide squeezing force, the reset spring 33 pushes the expansion key 31 and the expansion plate 32 to reset them and prevent the expansion key 31 from getting stuck.

[0028] Furthermore, the inflatable component 2 also includes an inflation head 22 and a plug 23. The plug 23, the airbag tube 21 and the inflation head 22 are arranged in sequence from front to back. The inflation head 22 is arranged in the first inner hole, and the plug 23 is fixed to the first inner hole. The inflation head 22 is provided with an inflation port that passes through the front-to-back direction. One end of the tube hole of the airbag tube 21 is connected to the inflation port, and the inflation port is used to connect to the air pump. The plug 23 blocks the other end of the tube hole of the airbag tube 21, wherein the air pump is inserted into the first inner hole from the rear through the trachea and connected to the inflation port to inflate the airbag tube 21. Further, the shape of the inflation head 22 can be adapted to the first inner hole so that the outer side wall of the inflation head 22 abuts against the first inner hole.

[0029] Furthermore, the sleeve assembly 1 also includes an extension tube 12, which is provided with a second inner hole passing through along its axis. The extension tube 12 is fixedly sleeved on the outside of the main tube 11 and protrudes in front of the main tube 11, so that other functional components can be arranged in front of the main tube 11 and on the extension tube 12.

[0030] Furthermore, it also includes a first limit component 4, which includes a limit pin 41 and a first driver 42. The outer wall of the extension tube 12 is provided with a limit hole that penetrates to the second inner hole. The first driver 42 is fixed to the second inner hole, and the limit pin 41 is provided in the limit hole. The first driver 42 is connected to the limit pin 41. The first driver 42 can drive the limit pin 41 to move in a direction away from the second inner hole until it protrudes from the outer wall of the extension tube 12. The first limit component 4 is used to prevent the coil 8 from moving axially along the main tube 11 to detachment and falling due to insufficient friction. The first driver 42 can be an electromagnetic driver that pushes the limit pin 41 by magnetic force.

[0031] Furthermore, it also includes an anti-collision component 6, which includes an anti-collision block 61, a pressure sensor 62 and a plurality of anti-collision units 63. The anti-collision block 61 is arranged in front of the extension tube 12, and the anti-collision block 61 is provided with a plurality of first connecting holes arranged around the axis of the anti-collision block 61. The first connecting hole passes through in the front-to-back direction. A mounting boss is provided in the inner ring of the first connecting hole. The front of the extension tube 12 is provided with a plurality of second connecting holes corresponding to the first connecting holes one by one. The second connecting holes are provided with threads. The anti-collision units 63 correspond to the first connecting holes and the second connecting holes one by one. The anti-collision unit 63 includes an anti-collision spring 631 and a connecting screw 632. The connecting screw 632 passes through the first connecting hole, the connecting screw 632 is inserted into the second connecting hole, and the connecting screw 632 is threadedly connected In the second connecting hole, the back of the screw head of the connecting screw abuts against the front of the mounting boss, and the anti-collision spring 631 is sleeved on the outside of the connecting screw 632. One end of the anti-collision spring 631 abuts against the front of the extension tube 12 and the other end abuts against the back of the mounting boss. The pressure sensor 62 is fixed to the second inner hole, and the pressure sensor 62 faces the anti-collision block 61. The pressure sensor 62 is used to detect the pressure applied to the anti-collision block 61. When the anti-collision block 61 collides with the material, the anti-collision block 61 moves backward, and the anti-collision spring 631 absorbs part of the impact force, reducing the probability of damage to the front end of the extension tube 12 and the coil 8, and detects the pressure applied to the anti-collision block 61 through the pressure sensor 62 to determine whether the device or the coil 8 is damaged, wherein the anti-collision block 61 can be made of nylon.

[0032] Furthermore, the inflatable component 2 also includes a wiring tube 24, which is arranged in the first inner hole, the inflation head 22 is provided with a first wiring hole 221 that passes through in the front-to-back direction, and the plug 23 is provided with a second wiring hole 231 that passes through in the front-to-back direction. The two ends of the wiring tube 24 are respectively connected to the first wiring hole 221 and the second wiring hole 231, wherein the line enters from the rear end of the first inner hole, passes through the first wiring hole 221, the tube hole of the wiring tube 24 and the second wiring hole 231 in turn to reach the second inner hole, and then is connected to the first driver 42 and the pressure sensor 62.

[0033] Furthermore, the outer wall of the plug 23 is provided with an external thread, the first inner hole is provided with an internal thread, the plug 23 is threadedly connected to the first inner hole, the outer wall of the main pipe 11 is provided with an external thread, the second inner hole is provided with an internal thread, and the main pipe 11 is threadedly connected to the second inner hole. Specifically, the front end of the first inner hole is provided with an internal thread, the front end of the outer wall of the main pipe 11 is provided with an external thread, and the rear end of the second inner hole is provided with an internal thread.

[0034] Furthermore, in order to make it easier for the present invention to fork the coil 8 and allow the coil 8 to be more smoothly inserted into the main pipe 11, the expansion rod also includes a plurality of wheel assemblies 7, and the plurality of wheel assemblies 7 are evenly distributed along the circumference of the extension tube 12, and the wheel assembly 7 includes a pulley 71 and a wheel frame 72. The outer wall of the extension tube 12 is provided with a plurality of wheel holes 121 passing through the second inner hole, and the wheel holes 121 correspond one-to-one to the wheel assemblies 7, and the wheel frame 72 is fixed to the second inner hole, and the pulley 71 is provided in the wheel hole 121. The pulley 71 is rotatably connected to the wheel frame 72, and the wheel surface of the pulley 71 protrudes from the outer side surface of the extension tube 12, and the distance that the wheel surface of the pulley 71 protrudes from the outer side surface of the extension tube 12 is greater than 2 mm.

[0035] Furthermore, the expansion assembly 3 also includes a plurality of reset pins 34 corresponding one to one to the reset holes 1112. The reset holes 1112 penetrate the outer wall of the main pipe 11. The reset pins 34 are fixed in the reset holes 1112. One end of the reset spring 33 is connected to the reset pin 34, so that the reset hole 1112 is easier to process, and the spring thrust of the reset spring 33 on the expansion plate 32 can be adjusted by the depth of the reset pin 34 in the reset hole 1112.

[0036] Furthermore, it also includes a second limit assembly 5, which is arranged behind the air expansion assembly 2 and the tightening assembly 3, and the second limit assembly 5 includes a clamp 51, a limit block 52 and a distance sensor 53. The limit block 52 is a semi-annular block, and the clamp 51 is a semi-annular hoop. The limit block 52 is fixedly connected to the clamp 51, and the limit block 52 and the clamp 51 form a card hole adapted to the outer wall of the main pipe 11. The main pipe 11 passes through the card hole, and the limit block 52 and the clamp 51 are clamped to the main pipe 11. A mounting hole is provided in front of the limit block 52, and the distance sensor 53 is fixedly arranged in the mounting hole. The distance sensor 53 faces forward, wherein the limit block 52 is used to prevent the coil 8 from continuing to move backward, and the distance sensor 53 is used to detect the distance between the limit block 52 and the coil 8. When the distance is less than a set value, the coil 8 is stopped from moving backward.

[0037] Furthermore, the specific connection methods of fixed setting and fixed connection refer to the relative position relationship of two components that can be fixedly connected, including fixing by connecting parts, fixing by welding, fixing by adhesives, fixing by integral molding, and fixing by snap connections.

[0038] Furthermore, the specific connection method of the detachable connection refers to the two connected parts being able to be disassembled and assembled repeatedly and multiple times without being damaged or seriously deformed, including fixation by a connector and fixation by a snap connection.

[0039] Furthermore, a sliding connection refers to a connection between two connected parts, in which one part can slide on the other part along a fixed track, including connection by sliding a slider into a slide groove, and connection by inserting a slide rod into a hole that matches the size profile of the slide rod.

[0040] Furthermore, the specific connection method of the adjustable connection means that the two connected parts can adjust their relative position relationship and then be fixed, and the aforementioned adjustment and fixing process can be repeated, including connection through long holes and connecting parts, and connection through sliding connection plus detachable connection.

[0041] Furthermore, the rotational connection refers to the ability of two connected parts to rotate, including connection through bearings and connection through clearance fit.

[0042] Furthermore, the connecting parts include fasteners, straps, ties, pneumatic connecting elements, hydraulic connecting elements, flange plates, Velcro, and buttons.

[0043] In summary, the embodiment of the present invention provides an expansion rod, the technical effects of which are:

[0044] The airbag tube 21 of the present invention is arranged in the first inner hole of the main tube 11, and multiple expansion components 3 are evenly distributed around the airbag tube 21, so that when the airbag tube 21 expands, the airbag tube 21 can evenly squeeze each expansion component 3. Furthermore, the expansion plate 32 of the expansion component 3 is arranged in the first inner hole, and the expansion key 31 of the expansion component 3 is arranged in the key hole 1111 of the working hole group 111. The expansion key 31 is arranged on one side of the expansion plate 32 of the expansion component 3, and the other side of the expansion plate 32 faces the airbag tube 21, so that when the airbag tube 21 expands, the airbag tube 21 squeezes the expansion plate 32, so that the expansion key 31 moves in the direction away from the first inner hole until the expansion key 31 squeezes the coil 8 sleeved on the outside of the main pipe 11 to provide friction for it. The expansion plate 32 can abut against the outer wall of the first inner hole to prevent the expansion key 31 from falling out of the key hole 1111. Furthermore, the two ends of the reset spring 33 are respectively connected to the expansion plate 32 and the reset hole 1112 of the working hole group 111 to provide a force to the expansion plate 32 toward the axis of the main pipe 11. When the airbag shrinks and the airbag does not provide extrusion force, the reset spring 33 pushes the expansion key 31 and the expansion plate 32 to reset them and prevent the expansion key 31 from getting stuck.

[0045] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and replacements can be made without departing from the technical principles of the present invention. These improvements and replacements should also be regarded as the scope of protection of the present invention.

Claims

1. An expansion rod, characterized in that: The invention comprises a sleeve assembly (1), an air expansion assembly (2) and a plurality of expansion assemblies (3), wherein the sleeve assembly (1) comprises a main pipe (11), the main pipe (11) is provided with a first inner hole passing through along its axis, the air expansion assembly (2) comprises an air bag tube (21), the air bag tube (21) is provided in the first inner hole, the hole wall of the first inner hole is provided with a plurality of operation hole groups (111) corresponding to the expansion assembly (3) one by one around the air bag tube (21), the operation hole group (111) comprises a key hole (1111) and a plurality of reset holes (1112), the key hole (1111) passes through the outer wall of the main pipe (11), the expansion assembly (3) is provided with a plurality of reset holes (1112), the key hole (1111) passes through the outer wall of the main pipe (11), the expansion assembly (3) is provided with a plurality of reset holes (1112), the key hole (1111) passes through the outer wall of the expansion assembly (3 ... expansion assembly (3) is provided with a plurality of reset holes (1112), the expansion assembly (3) is provided with a plurality of reset holes (1112), the expansion assembly (3) is provided with a plurality of reset holes (1112), the expansion assembly (3) is provided with a plurality of reset holes (1112), the expansion assembly (3) is provided with a plurality of reset holes ( The component (3) includes an expansion key (31), an expansion plate (32) and a plurality of return springs (33), wherein the expansion key (31) is arranged in the key hole (1111), and the expansion plate (32) is arranged in the first inner hole. The two opposite end faces of the expansion plate (32) are respectively connected to the expansion key (31) and relative to the airbag tube (21), and the two ends of the return spring (33) are respectively connected to the return hole (1112) and the expansion plate (32). When the airbag tube (21) expands, the airbag tube (21) squeezes each expansion plate (32), so that each expansion key (31) moves in a direction away from the first inner hole.

2. The expansion rod according to claim 1, characterized in that The inflatable component (2) further comprises an inflation head (22) and a plug (23), wherein the plug (23), the airbag tube (21) and the inflation head (22) are arranged in sequence from front to back, the inflation head (22) is arranged in the first inner hole, the plug (23) is fixed in the first inner hole, the inflation head (22) is provided with an inflation port which passes through in the front-to-back direction, one end of the tube hole of the airbag tube (21) is connected to the inflation port, and the inflation port is used to be connected to an air pump, and the plug (23) blocks the other end of the tube hole of the airbag tube (21).

3. The expansion rod according to claim 2, characterized in that: The sleeve assembly (1) further comprises an extension tube (12), wherein the extension tube (12) is provided with a second inner hole extending along its axis. The extension tube (12) is fixedly sleeved on the outside of the main tube (11) and protrudes in front of the main tube (11).

4. The expansion rod according to claim 3, characterized in that: The invention also includes a first limiting component (4), wherein the first limiting component (4) includes a limiting pin (41) and a first driver (42), the outer wall of the extension tube (12) is provided with a limiting hole extending through the second inner hole, the first driver (42) is fixed to the second inner hole, the limiting pin (41) is provided in the limiting hole, the first driver (42) is connected to the limiting pin (41), and the first driver (42) can drive the limiting pin (41) to move in a direction away from the second inner hole until it protrudes from the outer wall of the extension tube (12).

5. The expansion rod according to claim 3, characterized in that: The anti-collision assembly (6) further comprises an anti-collision block (61), a pressure sensor (62) and a plurality of anti-collision units (63). The anti-collision block (61) is arranged in front of the extension tube (12). The anti-collision block (61) is provided with a plurality of first connection holes arranged around the axis of the anti-collision block (61). The first connection holes are passed through in the front-to-back direction. The inner ring of the first connection hole is provided with a mounting boss. The front of the extension tube (12) is provided with a plurality of second connection holes corresponding to the first connection holes one by one. The second connection holes are provided with threads. The anti-collision units (63) correspond to the first connection holes and the second connection holes one by one. The anti-collision units (63) comprise an anti-collision spring (631) and a connecting screw (631). 32), the connecting screw (632) passes through the first connecting hole, the connecting screw (632) is inserted into the second connecting hole, the connecting screw (632) is threadedly connected to the second connecting hole, the rear side of the screw head of the connecting screw abuts against the front side of the mounting boss, the anti-collision spring (631) is sleeved on the outside of the connecting screw (632), one end of the anti-collision spring (631) abuts against the front side of the extension tube (12), and the other end abuts against the rear side of the mounting boss, the pressure sensor (62) is fixed to the second inner hole, the pressure sensor (62) faces the anti-collision block (61), and the pressure sensor (62) is used to detect the pressure applied to the anti-collision block (61).

6. The expansion rod according to any one of claims 3 to 5, characterized in that: The inflatable assembly (2) further comprises a wiring tube (24), wherein the wiring tube (24) is arranged in the first inner hole, the inflation head (22) is provided with a first wiring hole (221) extending in the front-to-back direction, the plug (23) is provided with a second wiring hole (231) extending in the front-to-back direction, and the two ends of the wiring tube (24) are respectively connected to the first wiring hole (221) and the second wiring hole (231).

7. The expansion rod according to claim 3, characterized in that: The outer wall of the plug (23) is provided with an external thread, the first inner hole is provided with an internal thread, the plug (23) is threadedly connected to the first inner hole, the outer wall of the main pipe (11) is provided with an external thread, the second inner hole is provided with an internal thread, and the main pipe (11) is threadedly connected to the second inner hole.

8. The expansion rod according to claim 3, characterized in that: The invention also includes a plurality of wheel assemblies (7), wherein the plurality of wheel assemblies (7) are evenly distributed along the circumference of the extension tube (12), the wheel assembly (7) includes a pulley (71) and a wheel frame (72), the outer wall of the extension tube (12) is provided with a plurality of wheel holes (121) penetrating the second inner hole, the wheel holes (121) correspond one to one to the wheel assemblies (7), the wheel frame (72) is fixedly provided in the second inner hole, the pulley (71) is provided in the wheel hole (121), the pulley (71) is rotatably connected to the wheel frame (72), and the wheel surface of the pulley (71) protrudes from the outer side surface of the extension tube (12).

9. The expansion rod according to claim 1, characterized in that: The expansion assembly (3) further includes a plurality of reset pins (34) corresponding one to one to the reset holes (1112), the reset holes (1112) extending through the outer wall of the main pipe (11), the reset pins (34) being fixed in the reset holes (1112), and one end of the reset spring (33) being connected to the reset pins (34).

10. The expansion rod according to claim 1, characterized in that The invention also includes a second limiting assembly (5), which is arranged behind the air expansion assembly (2) and the tightening assembly (3). The second limiting assembly (5) includes a clamp (51), a limiting block (52) and a distance sensor (53). The limiting block (52) is a semi-annular block, and the clamp (51) is a semi-annular hoop. The limiting block (52) is fixedly connected to the clamp (51). The limiting block (52) and the clamp (51) form a clamping hole adapted to the outer wall of the main pipe (11). The main pipe (11) passes through the clamping hole. The limiting block (52) and the clamp (51) are clamped to the main pipe (11). A mounting hole is provided in front of the limiting block (52). The distance sensor (53) is fixedly arranged in the mounting hole. The distance sensor (53) faces forward.

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