Flaring device for pipe bending machine

Abstract

The invention belongs to the field of pipe fitting machining, and particularly relates to a flaring device for a pipe bender, the flaring device comprises a fixed box, the inner wall of the fixed box is fixedly connected with a pipe expanding device, the left end of the pipe expanding device extends to the outside of the fixed box, and the bottom end of a pressure pump extends to the inside of the fixed box. The bottom end of the pressure pump is fixedly connected with the outer surface of a pipe expanding device, and the left end of the pipe expanding device is fixedly connected with an external push plate. According to the device, an external push plate is pushed through a pushing machine, a pipe expanding device is started to expand a pipe, however, the pushing machine needs a large occupied space, the pushing machine is very difficult to use in places such as workshops with stricter space requirements, economic benefits are poor, at the moment, the interior of the pipe expanding device can be pressurized through a pressure pump, and pipe expanding is completed; a pusher is not needed, the occupied area is effectively saved, the space utilization rate is increased, the size of the device can be further reduced, and the practicability is higher.

Description

Technical Field

[0001] The invention belongs to the field of pipe processing, in particular to an expanding device for a pipe bending machine. Background Art

[0002] The pipe bender is used to bend the pipe, and when the pipe is put into use, the ends of the pipes are generally expanded. However, the pipe bender generally does not have the function of bending pipes, so when expanding the pipes, a special expansion device is required to expand the pipes. Common expansion forms include R-end, stopper, rectangular end, etc.

[0003] According to the different specifications of the pipes, there are requirements for the flaring length, but the existing technology generally cannot accurately control the flaring length and cannot adapt to pipes of different specifications. In addition, the diameters of the pipes are varied. The existing flaring device can usually only flare a certain type of pipe, and cannot flare other types of pipes, and has poor adaptability. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides a flaring device for a pipe bending machine to solve the problems.

[0005] The technical solution adopted by the present invention to solve its technical problem is: the expanding device for a pipe bending machine described in the present invention includes a fixed box, the inner wall of the fixed box is fixedly connected to a pipe expanding device, the left end of the pipe expanding device extends to the outside of the fixed box, the left side of the outer surface of the fixed box is fixedly connected to a pressure pump, the bottom end of the pressure pump extends to the inside of the fixed box, the bottom end of the pressure pump is fixedly connected to the outer surface of the pipe expanding device, and the left end of the pipe expanding device is fixedly connected to an external push plate.

[0006] Preferably, the pipe expanding device includes a base plate, a slide groove is provided on the left side of the upper surface of the base plate, a support column is slidably connected to the left side of the upper surface of the base plate through the slide groove, a pipe expander is fixedly connected to the upper surface of the support column, a push rod is fixedly connected to the front side of the support column, and a secondary push rod is fixedly connected to the back side of the support column.

[0007] Preferably, the pipe expansion device includes a fixed base, the lower surface of the fixed base is fixedly connected to the right side of the upper surface of the base plate, the left side of the inner cavity of the fixed base is slidably connected with a pry bar device through a groove, the right side of the inner cavity of the fixed base is provided with a scale dial through a groove, the bottom of the inner cavity of the fixed base is provided with an adjustment device through a groove, and the lower surface of the adjustment device is fixedly connected to the upper surface of the base plate.

[0008] Preferably, the pipe expander includes a sealing box, a reinforcing shell is slidably connected to the middle part of the inner wall of the sealing box, an air duct is fixedly connected to the middle part of the inner wall of the reinforcing shell, both ends of the air duct extend to the outside of the fixed box, both ends of the air duct are fixedly connected to the bottom end of the pressure pump, an elastic sleeve is fixedly connected to the right side of the inner cavity of the reinforcing shell, the left end of the elastic sleeve extends to the inside of the reinforcing shell, the right end of the elastic sleeve extends to the outside of the sealing box, and the right side of the inner wall of the elastic sleeve is bolted with an adjustment plug.

[0009] Preferably, the pry bar device includes a parallel sliding bar group, the left end of the parallel sliding bar group is fixedly connected to the right side of the outer surface of the support column, the right end of the parallel sliding bar group is slidingly connected to the right side of the inner cavity of the fixed base through a sliding groove, a moving rod is provided at the top of the outer surface of the parallel sliding bar group, the moving rod is slidingly connected to the right side of the inner cavity of the fixed base through the sliding groove, the top of the moving rod extends to the outside of the fixed base, the bottom end of the moving rod is slidingly connected to the outer surface of the parallel sliding bar group, the middle part of the outer surface of the moving rod is slidingly connected to a limiting ring, and the outer surface of the limiting ring is fixedly connected to the inner cavity of the fixed base through the sliding groove.

[0010] Preferably, the adjustment device includes a bolt sleeve, the lower surface of which is fixedly connected to the upper surface of the base plate, the upper part of the inner wall of the bolt sleeve is connected to a threaded push rod via a threaded bolt, the upper surface of the threaded push rod is fixedly connected to a force-bearing push plate, the upper surface of the force-bearing push plate is fixedly connected to a connecting plate, the side surface of the force-bearing push plate is slidingly connected to the inner wall of the fixed base, the right side of the outer surface of the threaded push rod is meshingly connected to a rotating gear, the axis of the inner wall of the rotating gear is fixedly connected to a shaft rod, the rear end of the shaft rod extends to the outside of the fixed box, and the back of the outer surface of the shaft rod is rotatably connected to the inner cavity of the fixed box through a hole.

[0011] Preferably, the scale dial includes an auxiliary slide bar, the left side of the outer surface of the auxiliary slide bar is fixedly connected to the right side of the outer surface of the connecting plate, the right side of the outer surface of the auxiliary slide bar is fixedly connected to a pointer bar, the right side of the inner cavity of the pointer bar is slidably connected to the right side of the outer surface of the fixed base, and the right side of the outer surface of the fixed base is fixedly connected to a scale bar.

[0012] Preferably, the scale dial includes a large groove clamp, the lower surface of the large groove clamp is fixedly connected to the upper surface of the fixed base, the upper surface of the large groove clamp is slidably connected with a fastening sleeve, and the lower surface of the fastening sleeve is clamped with the upper surface of the connecting plate.

[0013] The beneficial effects of the present invention are as follows: 1. Under normal circumstances, the device uses a pusher to push the external push plate to start the pipe expansion device to expand the pipe. However, the pusher requires a large space. In places such as factories where space requirements are more stringent, it is very difficult to use a pusher, and the economic benefits are poor. At this time, a pressure pump can be used to pressurize the inside of the pipe expansion device to complete the pipe expansion. There is no need to use a pusher, which effectively saves floor space and improves space utilization. The size of the device can be further reduced and the practical performance is stronger.

[0014] 2. Since the device has two starting modes, pressure drive and external force drive, and the two driving modes can cooperate with each other or be driven separately, if the driving force of the pusher is poor and the pipe material is hard, the thrust of the pusher cannot meet the pipe expansion requirements. At this time, the booster pump can increase the thrust of the pusher on the pipe by increasing the pressure, thereby completing the pipe expansion. If a certain driving mode fails, such as the booster pump failure or the pusher failure, the device can switch the driving mode at any time to ensure the normal progress of the pipe expansion process.

[0015] 3. Since the adjusting plug is connected to the elastic sleeve bolt, the adjusting plug can be replaced at any time to adapt to different types of pipe expansion, and it is also convenient for subsequent device maintenance and repair work.

[0016] 4. After expansion, the end of the pipe is easily stuck in the inner wall of the large groove splint. At this time, the pipe is difficult to remove, so a pry bar device is needed to assist. When the pipe is expanded, the pipe expander is separated from the inner wall of the pipe and slides on the bottom plate through the support column. When the parallel slide bar group slides horizontally, it will push the moving rod upward. When the top of the moving rod rises, the pipe stuck in the inner wall of the large groove splint can be pushed out of the large groove splint, making it easier for users to remove the pipe.

[0017] 5. Since the device can process different types of pipes, it is necessary to adjust the size of the clamp for tightening the pipe sleeve according to the diameter of the pipe to prevent the right side of the pipe from loosening during expansion and affecting the shape of the flared mouth. The user controls the rotating gear through the shaft rod to rotate and drive the threaded push rod to rise and fall. At this time, the force-bearing push plate can control the horizontal movement of the connecting plate, thereby ensuring the tightness of the tightening pipe sleeve.

[0018] 6. Before using the adjustment device to clamp the pipe, the user needs to estimate the diameter of the pipe being processed and rotate the shaft to the appropriate position according to the indication of the pointer bar to prevent the right side of the pipe from being deformed due to excessive clamping of the tightening sleeve, thus affecting the overall shape of the pipe. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a front view of the present invention; Figure 2 is a cross-sectional view of the pipe expansion device of the present invention; Figure 3 is a cross-sectional view of the pipe expanding machine of the present invention; Figure 4 It is a structural schematic diagram of the pry bar device of the present invention; Figure 5 It is a structural schematic diagram of the image adjustment device of the present invention; Figure 6 It is a structural schematic diagram of a scale dial of the present invention.

[0020] In the figure: fixed box 1, pipe expansion device 2, pressure pump 3, external push plate 4, bottom plate 21, support column 22, push rod 23, fixed base 24, pipe expander 5, sealing box 51, strengthening shell 52, elastic sleeve 53, adjustment plug 54, air guide tube 55, pry bar device 6, parallel slide bar group 61, moving rod 62, limit collar 64, adjustment device 7, bolt sleeve 71, threaded push rod 72, shaft rod 73, rotating gear 74, force push plate 75, connecting plate 76, scale dial 8, auxiliary slide bar 81, pointer bar 82, scale bar 83, large groove clamping plate 84, fastening pipe sleeve 85. DETAILED DESCRIPTION

[0021] use Figure 1-Figure 6 An expansion device for a pipe bending machine according to an embodiment of the present invention is described as follows.

[0022] like Figure 1-Figure 6 As shown, a flaring device for a pipe bending machine described in the present invention comprises a fixed box 1, the inner wall of the fixed box 1 is fixedly connected with a pipe expanding device 2, the left end of the pipe expanding device 2 extends to the outside of the fixed box 1, the left side of the outer surface of the fixed box 1 is fixedly connected with a pressure pump 3, the bottom end of the pressure pump 3 extends to the inside of the fixed box 1, the bottom end of the pressure pump 3 is fixedly connected to the outer surface of the pipe expanding device 2, and the left end of the pipe expanding device 2 is fixedly connected with an external push plate 4. When the device is in use, the pipe to be expanded is inserted into the pipe expanding device 2 from the right side of the fixed box 1, and the external push plate 4 is pushed by the pusher after tightening. Push plate 4, at this time, the expansion device 2 expands the right end of the pipe, and then opens the expansion device 2 to take out the expanded pipe. Under normal circumstances, the device pushes the external push plate 4 through a pusher to start the expansion device 2 to expand the pipe, but the pusher requires a large space. In places such as factories where space requirements are more stringent, it is very difficult to use a pusher, and the economic benefits are poor. At this time, the pressure pump 3 can be used to pressurize the inside of the expansion device 2 to complete the expansion. There is no need to use a pusher, which effectively saves floor space and improves space utilization. The volume of the device can be further reduced and the practical performance is stronger.

[0023] The pipe expanding device 2 comprises a base plate 21, a slide groove is provided on the left side of the upper surface of the base plate 21, a support column 22 is slidably connected to the left side of the upper surface of the base plate 21 through the slide groove, a pipe expanding machine 5 is fixedly connected to the upper surface of the support column 22, a push rod 23 is fixedly connected to the front of the support column 22, and an auxiliary push rod 23 is fixedly connected to the back of the support column 22. Since the device has two starting modes, namely pressure drive and external force drive, and the two driving modes can cooperate with each other and can also be driven separately, if the driving force of the pusher is poor and the material of the pipe is hard, the thrust of the pusher cannot meet the pipe expansion demand. At this time, the pressure pump 3 can increase the thrust of the pusher on the pipe by pressurizing, thereby completing the expansion of the pipe. If a certain driving mode fails, such as the failure of the pressure pump 3 or the failure of the pusher, the device can switch the driving mode at any time to ensure the normal progress of the pipe expansion process.

[0024] The pipe expansion device 2 includes a fixed base 24, the lower surface of which is fixedly connected to the right side of the upper surface of the bottom plate 21, the left side of the inner cavity of the fixed base 24 is slidably connected with a pry bar device 6 through a groove, the right side of the inner cavity of the fixed base 24 is provided with a scale dial 8 through a groove, and the bottom of the inner cavity of the fixed base 24 is provided with an adjustment device 7 through a groove, and the lower surface of the adjustment device 7 is fixedly connected to the upper surface of the bottom plate 21.

[0025] The pipe expander 5 includes a sealing box 51, a reinforcing shell 52 is slidably connected to the middle of the inner wall of the sealing box 51, an air guide pipe 55 is fixedly connected to the middle of the inner wall of the reinforcing shell 52, both ends of the air guide pipe 55 extend to the outside of the fixed box 1, both ends of the air guide pipe 55 are fixedly connected to the bottom end of the booster pump 3, an elastic sleeve 53 is fixedly connected to the right side of the inner cavity of the reinforcing shell 52, the left end of the elastic sleeve 53 extends to the inside of the reinforcing shell 52, and the right end of the elastic sleeve 53 extends to the outside of the sealing box 51, and the right side of the inner wall of the elastic sleeve 53 is bolted with an adjustment plug 54. When the pusher pushes the external push plate 4, the external push plate 4 pushes the sealing box 51. The connecting pipe on the right side of the sealing box 51 pushes the strengthening shell 52 to slide to the right, thereby driving the adjusting plug 54 to be inserted into the right end of the pipe to complete the pipe expansion work; when the pressure pump 3 is used to drive, the pressure pump 3 pressurizes the interior of the strengthening shell 52 through the air guide pipe 55, and the elastic sleeve 53 is stretched at both ends under the action of pressure. The right end of the elastic sleeve 53 pushes the adjusting plug 54 to slide to the right, thereby driving the adjusting plug 54 to be inserted into the right end of the pipe to complete the pipe expansion work. Since the adjusting plug 54 is bolted to the elastic sleeve 53, the adjusting plug 54 can be replaced at any time to be suitable for the expansion of different types of pipes, and it is also convenient for subsequent device maintenance and repair work.

[0026] The pry bar device 6 includes a parallel slide bar group 61, the left end of the parallel slide bar group 61 is fixedly connected to the right side of the outer surface of the support column 22, the right end of the parallel slide bar group 61 is slidably connected to the right side of the inner cavity of the fixed base 24 through a slide groove, and a moving rod 62 is provided on the top of the outer surface of the parallel slide bar group 61. The moving rod 62 is slidably connected to the right side of the inner cavity of the fixed base 24 through a slide groove. The top of the moving rod 62 extends to the outside of the fixed base 24, the bottom end of the moving rod 62 is slidably connected to the outer surface of the parallel slide bar group 61, and the middle part of the outer surface of the moving rod 62 is slidably connected to The limiting ring 64, the outer surface of which is fixedly connected to the inner cavity of the fixed base 24 through a slide groove, the end of the pipe after expansion is easily stuck in the inner wall of the large groove clamp 84, and the pipe is difficult to take out at this time, so the pry bar device 6 is required to assist, when the pipe expansion is completed, the pipe expander 5 is separated from the inner wall of the pipe, and slides on the bottom plate 21 through the support column 22, and the parallel slide bar group 61 will push the moving rod 62 upward when sliding horizontally, and when the top end of the moving rod 62 rises, the pipe stuck in the inner wall of the large groove clamp 84 can be pushed out of the large groove clamp 84, so that the user can take out the pipe easily.

[0027] The adjusting device 7 includes a bolt sleeve 71, the lower surface of which is fixedly connected to the upper surface of the bottom plate 21, the upper part of the inner wall of the bolt sleeve 71 is connected to a threaded push rod 72 through a threaded bolt, the upper surface of the threaded push rod 72 is fixedly connected to a force-bearing push plate 75, the upper surface of the force-bearing push plate 75 is fixedly connected to a connecting plate 76, the side of the force-bearing push plate 75 is slidably connected to the inner wall of the fixed base 24, the right side of the outer surface of the threaded push rod 72 is meshedly connected to a rotating gear 74, and the axis of the inner wall of the rotating gear 74 is fixedly connected to a shaft rod 73. The rear end of the shaft 73 extends to the outside of the fixed box 1, and the back of the outer surface of the shaft 73 is rotatably connected to the inner cavity of the fixed box 1 through a hole. Since the device can process different types of pipes, it is necessary to adjust the size of the clamp of the fastening sleeve 85 according to the diameter of the pipe to prevent the right side of the pipe from loosening during expansion and affecting the shape of the flared mouth. The user controls the rotating gear 74 to rotate through the shaft 73 from the outside, driving the threaded push rod 72 to rise and fall. At this time, the force-bearing push plate 75 can control the horizontal movement of the connecting plate 76, thereby ensuring the tightness of the fastening sleeve 85.

[0028] The scale dial 8 includes an auxiliary slide bar 81, the left side of the outer surface of the auxiliary slide bar 81 is fixedly connected to the right side of the outer surface of the connecting plate 76, the right side of the outer surface of the auxiliary slide bar 81 is fixedly connected to a pointer bar 82, the right side of the inner cavity of the pointer bar 82 is slidably connected to the right side of the outer surface of the fixed base 24, and the right side of the outer surface of the fixed base 24 is fixedly connected to a scale bar 83.

[0029] The scale dial 8 includes a large groove clamping plate 84, the lower surface of which is fixedly connected to the upper surface of the fixed base 24, and the upper surface of the large groove clamping plate 84 is slidably connected with a fastening sleeve 85, and the lower surface of the fastening sleeve 85 is clamped with the upper surface of the connecting plate 76. Before using the adjustment device 7 to clamp the pipe, the user needs to estimate the diameter of the processed pipe and rotate the shaft 73 to a suitable position according to the indication of the pointer bar 82 to prevent the fastening sleeve 85 from being over-clamped and deforming the right side of the pipe, thereby affecting the overall shape of the pipe.

[0030] The specific workflow is as follows: When the device is in use, the pipe to be expanded is inserted into the pipe expanding device 2 from the right side of the fixed box 1. After tightening, the external push plate 4 is pushed by the pusher. At this time, the pipe expanding device 2 expands the right end of the pipe. Then the pipe expanding device 2 is opened to take out the expanded pipe. Under normal circumstances, the device pushes the external push plate 4 by the pusher to start the pipe expanding device 2 to expand the pipe. However, the pusher requires a large space. In places such as factories where space requirements are more stringent, it is very difficult to use a pusher and the economic benefits are poor. At this time, the pressure pump 3 can be used to pressurize the inside of the pipe expanding device 2 to complete the pipe expansion. There is no need to use a pusher, which effectively saves floor space and improves space utilization. The size of the device can be further reduced and the practical performance is stronger.

[0031] Since the device has two starting modes, pressure drive and external force drive, and the two driving modes can cooperate with each other and can also be driven separately, if the driving force of the pusher is poor and the pipe material is hard, the thrust of the pusher cannot meet the pipe expansion demand. At this time, the pressure pump 3 can increase the thrust of the pusher on the pipe by pressurizing, thereby completing the pipe expansion. If a certain driving mode fails, such as the failure of the pressure pump 3 or the failure of the pusher, the device can switch the driving mode at any time to ensure the normal progress of the pipe expansion process.

[0032] When the pusher pushes the external push plate 4, the external push plate 4 pushes the connecting pipe on the right side of the sealing box 51, and the connecting pipe pushes the strengthening shell 52 to slide to the right, thereby driving the adjusting plug 54 to be inserted into the right end of the pipe to complete the pipe expansion work; when the pressure pump 3 is used for driving, the pressure pump 3 pressurizes the interior of the strengthening shell 52 through the air guide pipe 55, and the elastic sleeve 53 is stretched at both ends under the action of pressure, and the right end of the elastic sleeve 53 pushes the adjusting plug 54 to slide to the right, thereby driving the adjusting plug 54 to be inserted into the right end of the pipe to complete the pipe expansion work. Since the adjusting plug 54 is bolted to the elastic sleeve 53, the adjusting plug 54 can be replaced at any time to be suitable for the expansion of different types of pipes, and it is also convenient for subsequent device maintenance and repair work.

[0033] The end of the expanded pipe is easily stuck in the inner wall of the large groove clamp 84. At this time, the pipe is difficult to remove, so the pry bar device 6 is required to assist. When the pipe is expanded, the pipe expander 5 is separated from the inner wall of the pipe and slides on the bottom plate 21 through the support column 22. When the parallel slide bar group 61 slides horizontally, it will push the moving rod 62 upward. When the top end of the moving rod 62 rises, the pipe stuck in the inner wall of the large groove clamp 84 can be pushed out of the large groove clamp 84, making it easier for the user to remove the pipe.

[0034] Since the device can process different types of pipes, it is necessary to adjust the size of the clamp of the fastening sleeve 85 according to the diameter of the pipe to prevent the right side of the pipe from loosening during expansion and affecting the shape of the flared mouth. The user controls the rotating gear 74 to rotate through the shaft 73 from the outside, driving the threaded push rod 72 to rise and fall. At this time, the force-bearing push plate 75 can control the horizontal movement of the connecting plate 76, thereby ensuring the tightness of the fastening sleeve 85.

[0035] Before using the adjustment device 7 to clamp the pipe, the user needs to estimate the diameter of the pipe to be processed and rotate the shaft 73 to a suitable position according to the indication of the pointer bar 82 to prevent the fastening sleeve 85 from over-clamping and deforming the right side of the pipe, thereby affecting the overall shape of the pipe.

[0036] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation modes, which are merely illustrative rather than restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the present invention and the claims, all of which are within the protection of the present invention.

Claims

1. A flaring device for a pipe bending machine, comprising a fixing box (1), characterized in that: The inner wall of the fixed box (1) is fixedly connected to a pipe expansion device (2), the left end of the pipe expansion device (2) extends to the outside of the fixed box (1), the left side of the outer surface of the fixed box (1) is fixedly connected to a pressure pump (3), the bottom end of the pressure pump (3) extends to the inside of the fixed box (1), the bottom end of the pressure pump (3) is fixedly connected to the outer surface of the pipe expansion device (2), and the left end of the pipe expansion device (2) is fixedly connected to an external push plate (4).

2. The expansion device for a pipe bender according to claim 1, characterized in that: The pipe expanding device (2) comprises a bottom plate (21), a slide groove is provided on the left side of the upper surface of the bottom plate (21), a support column (22) is slidably connected to the left side of the upper surface of the bottom plate (21) via the slide groove, a pipe expanding machine (5) is fixedly connected to the upper surface of the support column (22), a push rod (23) is fixedly connected to the front side of the support column (22), and an auxiliary push rod (23) is fixedly connected to the back side of the support column (22).

3. The expansion device for a pipe bender according to claim 1, characterized in that: The pipe expansion device (2) comprises a fixed base (24), the lower surface of the fixed base (24) is fixedly connected to the right side of the upper surface of the bottom plate (21), the left side of the inner cavity of the fixed base (24) is slidably connected to a pry bar device (6) via a slot, the right side of the inner cavity of the fixed base (24) is provided with a scale dial (8) via a slot, the bottom of the inner cavity of the fixed base (24) is provided with an adjustment device (7) via a slot, and the lower surface of the adjustment device (7) is fixedly connected to the upper surface of the bottom plate (21).

4. The expansion device for a pipe bender according to claim 2, characterized in that: The pipe expander (5) comprises a sealing box (51), a reinforcing shell (52) is slidably connected to the middle of the inner wall of the sealing box (51), an air guide pipe (55) is fixedly connected to the middle of the inner wall of the reinforcing shell (52), both ends of the air guide pipe (55) extend to the outside of the fixed box (1), both ends of the air guide pipe (55) are fixedly connected to the bottom end of the pressure pump (3), an elastic sleeve (53) is fixedly connected to the right side of the inner cavity of the reinforcing shell (52), the left end of the elastic sleeve (53) extends to the inside of the reinforcing shell (52), the right end of the elastic sleeve (53) extends to the outside of the sealing box (51), and the right side of the inner wall of the elastic sleeve (53) is bolted to an adjustment plug (54).

5. The expansion device for a pipe bender according to claim 3, characterized in that: The pry bar device (6) comprises a parallel slide bar group (61), the left end of the parallel slide bar group (61) is fixedly connected to the right side of the outer surface of the support column (22), the right end of the parallel slide bar group (61) is slidably connected to the right side of the inner cavity of the fixed base (24) through a slide groove, a moving rod (62) is arranged at the top of the outer surface of the parallel slide bar group (61), the moving rod (62) is slidably connected to the right side of the inner cavity of the fixed base (24) through the slide groove, the top end of the moving rod (62) extends to the outside of the fixed base (24), the bottom end of the moving rod (62) is slidably connected to the outer surface of the parallel slide bar group (61), the middle part of the outer surface of the moving rod (62) is slidably connected to a limiting ring (64), and the outer surface of the limiting ring (64) is fixedly connected to the inner cavity of the fixed base (24) through the slide groove.

6. The expansion device for a pipe bender according to claim 3, characterized in that: The adjustment device (7) comprises a bolt sleeve (71), the lower surface of which is fixedly connected to the upper surface of the base plate (21), the upper part of the inner wall of the bolt sleeve (71) is connected to a threaded push rod (72) via a threaded bolt, the upper surface of the threaded push rod (72) is fixedly connected to a force-bearing push plate (75), the upper surface of the force-bearing push plate (75) is fixedly connected to a connecting plate (76), the side surface of the force-bearing push plate (75) is slidably connected to the inner wall of the fixed base (24), the right side of the outer surface of the threaded push rod (72) is meshingly connected to a rotating gear (74), the axis of the inner wall of the rotating gear (74) is fixedly connected to a shaft rod (73), the rear end of the shaft rod (73) extends to the outside of the fixed box (1), and the back of the outer surface of the shaft rod (73) is rotatably connected to the inner cavity of the fixed box (1) through a hole.

7. The expansion device for a pipe bender according to claim 3, characterized in that: The graduated dial (8) comprises an auxiliary slide bar (81), the left side of the outer surface of the auxiliary slide bar (81) being fixedly connected to the right side of the outer surface of the connecting plate (76), a pointer bar (82) being fixedly connected to the right side of the outer surface of the auxiliary slide bar (81), the right side of the inner cavity of the pointer bar (82) being slidably connected to the right side of the outer surface of the fixed base (24), and a graduated bar (83) being fixedly connected to the right side of the outer surface of the fixed base (24).

8. The expansion device for a pipe bender according to claim 3, characterized in that: The graduated dial (8) comprises a large groove clamping plate (84), the lower surface of the large groove clamping plate (84) being fixedly connected to the upper surface of the fixed base (24), the upper surface of the large groove clamping plate (84) being slidably connected to a fastening sleeve (85), and the lower surface of the fastening sleeve (85) being snap-fitted to the upper surface of the connecting plate (76).

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