A cutting device for fire hydrant pipe

Abstract

The present invention relates to a cutting device for fire hydrant pipes applied to the field of fire fighting equipment processing, comprising a cutting table, on which two rows of supporting wheels for supporting the fire hydrant pipes are installed, a hydraulic cylinder and a cutting machine are fixed on one side of the cutting table, the cutting machine comprises a shell and a cutter rotatably installed in the shell, a driving mechanism for driving the cutter to rotate is installed outside the shell of the cutting machine, auxiliary driving wheels are installed on both sides of the cutter, the diameter of the auxiliary driving wheels is adjustable, the cutter drives the auxiliary driving wheels to rotate through a transmission structure, and the auxiliary driving wheels and the transmission structure are adopted to achieve the purpose of simultaneously driving the cutter and driving the fire hydrant pipe to rotate without using an additional power source, which is beneficial to reducing the energy consumption during the fire hydrant pipe cutting operation and realizing energy-saving processing; at the same time, the auxiliary driving wheel is set as a wheel body with an adjustable diameter, which can be applicable to the cutting operation of fire hydrant pipes with different wall thicknesses, thereby expanding the scope of application.

Description

Technical Field

[0001] The invention relates to a cutting device, in particular to a cutting device for fire hydrant pipes which is applied in the field of fire fighting equipment processing. Background Art

[0002] Fire hydrants are fixed fire-fighting facilities, and their main functions are to control combustibles, isolate combustion-supporting materials, and eliminate fire sources. Fire hydrants are mainly used for fire trucks to draw water from the municipal water supply network or outdoor fire water supply network to extinguish fires. They can also be directly connected to water hoses and water guns to discharge water for fire extinguishing. When installing fire hydrants, it is necessary to cut the fire hydrant pipe according to the actual installation size, which requires the use of a cutting device for fire hydrant pipes.

[0003] For example, the specification of Chinese patent CN206952740U discloses a fire hydrant pipe cutting device, including a cutting table, on which two slide rails are fixedly arranged parallel to each other on both sides of the tailstock and the chuck, two groups of gantry press frames are arranged on the slide rails, a cutting seat and a bracket are also arranged on the slide rails, and the cutting seat and the bracket are not on the same slide rail, a plurality of roller groups are fixedly arranged at equal intervals between the tailstock and the chuck and on the cutting table, the bottom of the cutting seat is slidably connected to the slide rail through a slide seat, a screw rod is arranged inside the cutting seat, an adjustment seat is arranged on the screw rod through a threaded connection, a cutting motor is fixedly arranged on the adjustment seat, and a cutting disc is fixedly arranged on the output shaft end of the cutting motor. This fire hydrant pipe cutting device can reduce the power selected for the cutting motor and the specifications of the cutting disc, reduce equipment investment and energy consumption, is conducive to timely heat dissipation, and improves the service life of the cutting disc. The nozzle blows away metal chips to ensure the flatness of the cutting port.

[0004] For another example, the specification of Chinese patent CN210877834U discloses a fire hydrant pipe cutting device, which includes a support frame and a workbench arranged on the top of the support frame, a cutting assembly is arranged at the bottom of the workbench, a pipe clamping assembly is arranged on the top surface of the workbench, the pipe clamping assembly includes a fixed clamping seat fixedly connected to the workbench and a movable clamping seat slidably connected to the workbench, a slide groove is opened on the workbench, a screw rod is rotatably connected in the slide groove, a slider located in the slide groove is arranged at the bottom of the movable clamping seat, the slider is threadedly connected to the screw rod, a three-jaw chuck is rotatably connected in the movable clamping seat, and a rotating assembly for driving the three-jaw chuck to rotate is arranged on the movable clamping seat.

[0005] After clamping the fire hydrant pipe, the above two fire hydrant pipe cutting devices both require an additional power source to drive the fire hydrant pipe to rotate, so that the cutting knife (cutting disc) can perform circular cutting on the fire hydrant pipe, but the additional power source undoubtedly increases the equipment cost and increases the energy consumption in the cutting operation. Summary of the invention

[0006] In view of the above-mentioned prior art, the technical problem to be solved by the present invention is how to provide a cutting device for fire hydrant pipes that uses a power source for rotating a cutting knife to drive the fire hydrant pipe to rotate, so as to reduce the equipment cost of the fire hydrant pipe cutting device, while reducing the energy consumption in the cutting operation, thereby achieving the purpose of energy-saving processing.

[0007] In order to solve the above problems, the present invention provides a cutting device for fire hydrant pipes, comprising a cutting table, on which two rows of support wheels for supporting the fire hydrant pipes are installed, a hydraulic cylinder and a cutting machine are fixed on one side of the cutting table, and the hydraulic cylinder is used to push the cutting machine towards or away from the support wheels;

[0008] The cutting machine comprises a housing and a cutting knife rotatably mounted in the housing, and a driving mechanism for driving the cutting knife to rotate is mounted outside the housing of the cutting machine;

[0009] Auxiliary drive wheels are installed on both sides of the cutter. When the blade of the cutter cuts through the wall of the fire hydrant pipe, the peripheral side of the auxiliary drive wheel abuts against the outer wall of the fire hydrant pipe and drives the fire hydrant pipe to rotate. The diameter of the auxiliary drive wheel is adjustable.

[0010] The cutter drives the auxiliary driving wheel to rotate through the transmission structure.

[0011] In the above-mentioned cutting device for fire hydrant pipes, the driving mechanism is used to drive the cutter of the cutting machine to rotate, and at the same time, the transmission structure is used to drive the auxiliary driving wheel to rotate, so that when the blade of the cutter cuts through the pipe wall of the fire hydrant pipe, the peripheral side of the auxiliary driving wheel abuts against the outer wall of the fire hydrant pipe and can drive the fire hydrant pipe to rotate, thereby completing the annular cutting of the fire hydrant pipe, which is conducive to achieving the purpose of driving the cutter and driving the fire hydrant pipe to rotate at the same time without using an additional power source, which is conducive to reducing the energy consumption during the fire hydrant pipe cutting operation and realizing energy-saving processing;

[0012] At the same time, the auxiliary driving wheel is set as a wheel body with adjustable diameter, which can adjust the distance between the front end of the auxiliary driving wheel and the front end of the cutter, so as to be suitable for cutting operations of fire hydrant pipes with different wall thicknesses, thereby expanding the application scope of the cutting device for fire hydrant pipes.

[0013] As a further supplement to the present application, the auxiliary drive wheel includes a fixed wheel and a plurality of tension wheels distributed along the circumference of the central axis of the fixed wheel, the fixed wheel includes a first wheel disc and a second wheel disc, the first wheel disc is rotatably connected to the second wheel disc through a sleeve shaft, and the plurality of tension wheels are movably connected between the first wheel disc and the second wheel disc through an adjusting structure, and the adjusting structure drives the tension wheels to move radially outward along the first wheel disc.

[0014] As a further supplement to the present application, the adjustment structure includes a straight groove and an arc groove, the straight groove is opened on the inner side of the first wheel disc, the straight groove extends radially outward to the circumference of the first wheel disc and forms an opening on the circumference of the first wheel disc, and the arc groove is opened on the second wheel disc, the arc groove extends in an arc shape to the circumference of the second wheel disc, and both ends of the arc groove are closed;

[0015] The adjustment structure also includes a slide bar and a cross bar. The slide bar is fixed to the side of the tensioning wheel close to the first wheel disc. The slide bar is slidably connected in the linear groove. The cross bar is rotationally connected to the end of the slide bar away from the tensioning wheel. The other end of the cross bar is slidably connected in the arc groove.

[0016] As a further supplement to the present application, a rotating wheel is fixed to one end of the cross bar away from the sliding bar, and the rotating wheel is rotatably arranged in the arc groove.

[0017] As a further supplement to the present application, a limiting hole is provided on the first wheel disc, and a limiting bolt is threadedly connected to the limiting hole. When the limiting bolt is tightened, one end thereof is pressed against the inner wall of the second wheel disc.

[0018] As a further supplement to this application, the driving mechanism includes:

[0019] A servo motor, wherein the servo motor is fixed to the outer side of the housing of the cutting machine;

[0020] Transmission wheels, two transmission wheels are provided, one of which is fixed on the output shaft of the servo motor;

[0021] A transmission belt, wherein the transmission belt transmission sleeve is arranged between two transmission wheels;

[0022] A rotating shaft is fixedly provided to penetrate the cutter and another transmission wheel.

[0023] As a further supplement to the present application, the transmission structure includes a reduction gear group, which is composed of a plurality of gears. The reduction gear group includes a first gear and a second gear. The first gear is fixedly mounted on the rotating shaft, the second gear is meshed with the first gear, and the diameter of the second gear is larger than the diameter of the first gear. The second gear is connected to the fixed wheel through a transmission shaft, and the other end of the transmission shaft passes through the fixed wheel and is rotatably connected to a connecting rod fixed to the outer casing of the cutting machine.

[0024] As a further supplement to the present application, a plurality of tension wheels are fixedly provided with flexible sleeves on their circumferences. The flexible sleeves are made of rubber material, and there are gaps between both ends of the flexible sleeves and the inner side walls of the first wheel disc and the second wheel disc.

[0025] In summary, the driving mechanism is used to drive the cutter of the cutting machine to rotate, and at the same time, the auxiliary driving wheel is driven to rotate through the transmission structure; specifically, after the servo motor is started, it drives one of the transmission wheels to rotate, the transmission wheel drives another transmission wheel to rotate through the transmission belt, and the other transmission wheel drives the rotating shaft to rotate, thereby driving the cutter to rotate through the rotating shaft, when the rotating shaft rotates, it drives the first gear to rotate at the same time, the first gear drives the second gear to rotate, and when the second gear rotates, the fixed wheel is driven to rotate through the transmission shaft, thereby driving the entire auxiliary driving wheel to rotate, so that when the blade of the cutter cuts through the pipe wall of the fire hydrant pipe, the peripheral side of the auxiliary driving wheel abuts against the outer wall of the fire hydrant pipe, and can drive the fire hydrant pipe to rotate, thereby completing the annular cutting of the fire hydrant pipe, which is conducive to completing the purpose of driving the cutter and driving the fire hydrant pipe to rotate at the same time without using an additional power source, which is conducive to reducing the energy consumption during the fire hydrant pipe cutting operation and realizing energy-saving processing;

[0026] Since the diameter of the second gear is larger than that of the first gear, the rotation speed of the second gear is slower, so that the rotation speed of the auxiliary driving wheel is slower, which can not only ensure the stable driving effect of the auxiliary driving wheel on the fire hydrant pipe, but also avoid strong collision between the auxiliary driving wheel and the fire hydrant pipe, and play a certain protective role on the auxiliary driving wheel and the fire hydrant pipe;

[0027] At the same time, the auxiliary driving wheel is set as a wheel body with adjustable diameter, which can adjust the distance between the front end of the auxiliary driving wheel and the front end of the cutter. When the diameter of the auxiliary driving wheel needs to be adjusted, the user only needs to rotate the first wheel disc so that the first wheel disc drives the sliding rod, the cross rod and the tensioning wheel to rotate synchronously. In this process, since the other end of the cross rod is slidably connected in the arc groove, the cross rod gradually slides outward along the arc groove and drives the sliding rod to move at the same time. The sliding rod produces a linear motion along the straight groove, thereby making the tensioning wheel extend outward. Finally, the limiting bolts are used to limit the adjusted first and second wheel discs, thereby fixing the adjusted auxiliary driving wheel, thereby completing the adjustment of the auxiliary driving wheel diameter; thus, it is suitable for cutting fire hydrant pipes with different wall thicknesses, thereby expanding the application range of the cutting device for fire hydrant pipes. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a schematic diagram of the overall structure of the first implementation method of the present application;

[0029] Figure 2 This is a schematic diagram of the structure of the cutter, drive mechanism, reduction gear set and auxiliary drive wheel of the first embodiment of the present application;

[0030] Figure 3 This is a schematic diagram of the auxiliary drive wheel structure of the first embodiment of the present application;

[0031] Figure 4 This is a schematic diagram of the second wheel structure of the first implementation mode of the present application;

[0032] Figure 5 This is a schematic diagram of the first wheel structure of the first implementation mode of the present application;

[0033] Figure 6 This is a schematic diagram of the tensioning wheel, the sliding rod, the cross rod and the rotating wheel structure of the first embodiment of the present application;

[0034] Figure 7 This is a schematic diagram of the driving mechanism structure of the first embodiment of the present application;

[0035] Figure 8 This is a schematic diagram of the structure of the reduction gear set according to the first embodiment of the present application;

[0036] Fig. 9 This is a schematic diagram of the structure in which the tensioning wheel is installed on the second wheel disc in the first embodiment of the present application;

[0037] Fig.10 This is a schematic structural diagram of the first embodiment of the present application in which the tensioning wheel is installed on the first wheel disc.

[0038] Description of the numbers in the figure:

[0039] 1. Cutting table; 2. Support wheel; 3. Hydraulic cylinder; 4. Cutting machine; 41. Cutter; 5. Driving mechanism; 51. Servo motor; 52. Transmission wheel; 53. Transmission belt; 54. Rotating shaft; 6. Reduction gear set; 61. First gear; 62. Second gear; 7. Auxiliary driving wheel; 71. Fixed wheel; 711. First wheel disc; 7111. Sleeve shaft; 712. Second wheel disc; 713. Linear groove; 714. Arc groove; 715. Limiting hole; 72. Tension wheel; 73. Slide rod; 74. Cross rod; 75. Rotating wheel; 76. Limiting bolt. DETAILED DESCRIPTION

[0040] An implementation method of the present application is described in detail below with reference to the accompanying drawings.

[0041] The first implementation method:

[0042] The present invention provides a cutting device for fire hydrant pipes, see Figure 1-Figure 2 , including a cutting table 1, on which two rows of support wheels 2 for supporting fire hydrant pipes are installed, and a hydraulic cylinder 3 and a cutting machine 4 are fixed on one side of the cutting table 1, and the hydraulic cylinder 3 is used to push the cutting machine 4 to move closer to or away from the support wheel 2;

[0043] The cutting machine 4 comprises a housing and a cutting knife 41 rotatably mounted in the housing. A driving mechanism 5 for driving the cutting knife 41 to rotate is mounted outside the housing of the cutting machine 4.

[0044] Auxiliary drive wheels 7 are installed on both sides of the cutter 41. When the blade of the cutter 41 cuts through the wall of the fire hydrant pipe, the peripheral side of the auxiliary drive wheel 7 abuts against the outer wall of the fire hydrant pipe and drives the fire hydrant pipe to rotate. The diameter of the auxiliary drive wheel 7 is adjustable.

[0045] The cutter 41 drives the auxiliary driving wheel 7 to rotate through the transmission structure.

[0046] Based on the above structure, the driving mechanism 5 is used to drive the cutter 41 of the cutting machine 4 to rotate, and at the same time, the auxiliary driving wheel 7 is driven to rotate through the transmission structure, so that when the blade of the cutter 41 cuts through the pipe wall of the fire hydrant pipe, the peripheral side of the auxiliary driving wheel 7 abuts against the outer wall of the fire hydrant pipe and can drive the fire hydrant pipe to rotate, thereby completing the annular cutting of the fire hydrant pipe, which is conducive to completing the purpose of driving the cutter 41 and driving the fire hydrant pipe to rotate at the same time without using an additional power source, which is conducive to reducing the energy consumption during the fire hydrant pipe cutting operation and realizing energy-saving processing;

[0047] At the same time, the auxiliary drive wheel 7 is set as a wheel body with adjustable diameter, which can adjust the distance between the front end of the auxiliary drive wheel 7 and the front end of the cutter 41, so as to be suitable for cutting operations of fire hydrant pipes with different wall thicknesses, thereby expanding the application range of the cutting device for fire hydrant pipes.

[0048] Figure 2-Figure 5 It is shown that the auxiliary driving wheel 7 includes a fixed wheel 71 and a plurality of tensioning wheels 72 distributed along the circumference of the central axis of the fixed wheel 71. The fixed wheel 71 includes a first wheel disc 711 and a second wheel disc 712. The first wheel disc 711 is rotatably connected to the second wheel disc 712 via a sleeve shaft 7111. The plurality of tensioning wheels 72 are movably connected between the first wheel disc 711 and the second wheel disc 712 via an adjusting structure. The adjusting structure drives the tensioning wheels 72 to move radially outward along the first wheel disc 711.

[0049] Driven by the adjusting structure, the tensioning wheel 72 can move radially outward along the first wheel disc 711, so that the tensioning wheel 72 extends. After multiple tensioning wheels 72 are extended at the same time, they form a ring distribution, which can form an auxiliary driving wheel 7 structure with a larger diameter, so that the distance between the front end of the auxiliary driving wheel 7 and the front end of the cutter 41 is reduced, that is, the distance between the front end of the first wheel disc 711 and the second wheel disc 712 and the front end of the cutter 41 is reduced to the distance between the front end of the tensioning wheel 72 and the front end of the cutter 41 after extension, so that when the front end blade of the cutter 41 cuts through the wall of the fire hydrant pipe, the front end of the tensioning wheel 72 abuts against the outer wall of the fire hydrant pipe, which is suitable for cutting fire hydrant pipes with different wall thicknesses, thereby achieving the purpose of expanding the application range of the cutting device for fire hydrant pipes.

[0050] Figure 4-Figure 6The adjustment structure includes a straight groove 713 and an arc groove 714. The straight groove 713 is provided on the inner side of the first wheel disc 711. The straight groove 713 extends radially outward to the circumference of the first wheel disc 711 and forms an opening on the circumference of the first wheel disc 711. The arc groove 714 is provided on the second wheel disc 712. The arc groove 714 extends in an arc shape to the circumference of the second wheel disc 712, and both ends of the arc groove 714 are closed.

[0051] The adjustment structure also includes a slide bar 73 and a cross bar 74. The slide bar 73 is fixed to one side of the tensioning wheel 72 close to the first wheel disc 711. The slide bar 73 is slidably connected in the linear groove 713. The cross bar 74 is rotationally connected to one end of the slide bar 73 away from the tensioning wheel 72. The other end of the cross bar 74 is slidably connected in the arc groove 714.

[0052] When it is necessary to adjust the diameter of the auxiliary drive wheel 7, that is, to drive the tensioning wheel 72 to extend outward, the user only needs to rotate the first wheel disc 711 so that the first wheel disc 711 drives the sliding rod 73, the cross rod 74 and the tensioning wheel 72 to rotate synchronously. In this process, since the other end of the cross rod 74 is slidably connected in the arc groove 714, the cross rod 74 gradually slides outward along the arc groove 714 and drives the sliding rod 73 to move at the same time. The sliding rod 73 produces a linear motion along the linear groove 713, thereby making the tensioning wheel 72 extend outward, thereby completing the adjustment of the diameter of the auxiliary drive wheel 7. The adjustment operation is simple, convenient and fast.

[0053] Figure 4 and Figure 6 It is shown that a rotating wheel 75 is fixed to one end of the cross bar 74 away from the slide bar 73 , and the rotating wheel 75 is rotatably arranged in the arc groove 714 .

[0054] By setting the rotating wheel 75, the sliding contact between the cross bar 74 and the inner side of the arc groove 714 is transformed into a rolling contact, so that the cross bar 74 can slide along the arc groove 714 more smoothly and steadily, and at the same time, the radial pressure generated between the arc groove 714 and the cross bar 74 is reduced, which can effectively avoid large wear between the end of the cross bar 74 and the arc groove 714, effectively extend the service life of the cross bar 74, and ensure that a stable adjustment effect is achieved when the diameter of the auxiliary drive wheel 7 is adjusted multiple times.

[0055] Figure 3 and Figure 5 It is shown that a limiting hole 715 is provided on the first wheel disc 711, and a limiting bolt 76 is connected to the inner thread of the limiting hole 715. When the limiting bolt 76 is tightened, one end of the limiting bolt 76 is pressed against the inner wall of the second wheel disc 712, thereby limiting the adjusted first wheel disc 711 and the second wheel disc 712, thereby fixing the adjusted auxiliary drive wheel 7, ensuring that the auxiliary drive wheel 7 maintains a fixed diameter during the subsequent rotation process, thereby realizing effective driving of the fire hydrant pipe.

[0056] Figure 2 and Figure 7 The driving mechanism 5 is shown to include a servo motor 51, a transmission wheel 52, a transmission belt 53 and a rotating shaft 54;

[0057] The servo motor 51 is fixed to the outer side of the housing of the cutting machine 4 , and two transmission wheels 52 are provided, wherein one transmission wheel 52 is fixed to the output shaft of the servo motor 51 , a transmission belt 53 is arranged between the two transmission wheels 52 , and a rotating shaft 54 ​​is fixedly passed through the cutter 41 and the other transmission wheel 52 .

[0058] After the servo motor 51 is started, it drives one of the transmission wheels 52 to rotate, and the transmission wheel 52 drives another transmission wheel 52 to rotate through the transmission belt 53, and the other transmission wheel 52 drives the rotating shaft 54 ​​to rotate, thereby driving the cutter 41 to rotate through the rotating shaft 54, so that the cutter 41 can complete the cutting operation of the fire hydrant pipe.

[0059] Figure 2 and Figure 8 The transmission structure is shown to include a reduction gear set 6, which is composed of a plurality of gears. The reduction gear set 6 includes a first gear 61 and a second gear 62. The first gear 61 is fixedly sleeved on the rotating shaft 54, the second gear 62 is meshed with the first gear 61, and the diameter of the second gear 62 is larger than the diameter of the first gear 61. The second gear 62 is connected to the fixed wheel 71 through a transmission shaft, and the other end of the transmission shaft passes through the fixed wheel 71 and is rotatably connected to a connecting rod fixed to the outer casing of the cutting machine 4.

[0060] Through the setting of the reduction gear set 6, when the rotating shaft 54 ​​rotates, the first gear 61 is driven to rotate at the same time, and the first gear 61 drives the second gear 62 to rotate. When the second gear 62 rotates, the fixed wheel 71 is driven to rotate through the transmission shaft, thereby driving the entire auxiliary driving wheel 7 to rotate. Since the diameter of the second gear 62 is larger than the diameter of the first gear 61, the rotation speed of the second gear 62 is slower, thereby making the rotation speed of the auxiliary driving wheel 7 slower, which can not only ensure the stable driving effect of the auxiliary driving wheel 7 on the fire hydrant pipe, but also avoid strong collision between the auxiliary driving wheel 7 and the fire hydrant pipe, and play a certain protective role on the auxiliary driving wheel 7 and the fire hydrant pipe.

[0061] It should be noted that the reduction gear set 6 in this embodiment is composed of two gears. In actual use, a combination of multiple gears can be selected to achieve a corresponding reduction effect.

[0062] In addition, in order to reduce the hard collision between the tension wheel 72 and the fire hydrant pipe when in contact, the following structure can also be used to protect the tension wheel 72 and the fire hydrant pipe:

[0063] A flexible sleeve (not shown in the figure) is fixedly provided on the circumference of multiple tensioning wheels 72. The flexible sleeve is made of rubber material, and there are gaps between the two ends of the flexible sleeve and the inner walls of the first wheel disc 711 and the second wheel disc 712, so that the tensioning wheel 72 can produce flexible contact when contacting the fire hydrant pipe, avoiding hard collision that causes serious wear (or damage) of the fire hydrant pipe or the tensioning wheel 72, and can also increase the friction force of the contact part between the tensioning wheel 72 and the fire hydrant pipe, making its driving more stable.

[0064] In view of current practical needs, the above-mentioned implementation mode adopted in this application is not limited to the scope of protection. Various changes made within the knowledge scope of technical personnel in this field without departing from the concept of this application still fall within the scope of protection of the present invention.

Claims

1. A cutting device for fire hydrant pipes, comprising a cutting table (1), on which two rows of support wheels (2) for supporting the fire hydrant pipes are mounted, a hydraulic cylinder (3) and a cutting machine (4) are fixed to one side of the cutting table (1), the hydraulic cylinder (3) being used to push the cutting machine (4) towards or away from the support wheels (2), characterized in that: The cutting machine (4) comprises a housing and a cutting knife (41) rotatably mounted in the housing, and a driving mechanism (5) for driving the cutting knife (41) to rotate is mounted outside the housing of the cutting machine (4); Auxiliary drive wheels (7) are installed on both sides of the cutter (41). When the blade of the cutter (41) cuts through the wall of the fire hydrant pipe, the peripheral side of the auxiliary drive wheel (7) abuts against the outer wall of the fire hydrant pipe and drives the fire hydrant pipe to rotate. The diameter of the auxiliary drive wheel (7) is adjustable. The cutter (41) drives the auxiliary drive wheel (7) to rotate via the transmission structure; The auxiliary drive wheel (7) comprises a fixed wheel (71) and a plurality of tensioning wheels (72) distributed along the circumference of the central axis of the fixed wheel (71); the fixed wheel (71) comprises a first wheel disc (711) and a second wheel disc (712); the first wheel disc (711) is rotatably connected to the second wheel disc (712) via a sleeve shaft (7111); the plurality of tensioning wheels (72) are movably connected between the first wheel disc (711) and the second wheel disc (712) via an adjustment structure; the adjustment structure drives the tensioning wheels (72) to move radially outward along the first wheel disc (711); The adjustment structure comprises a straight groove (713) and an arc groove (714); the straight groove (713) is provided on the inner side of the first wheel disc (711); the straight groove (713) extends radially outwardly to the circumference of the first wheel disc (711) and forms an opening on the circumference of the first wheel disc (711); the arc groove (714) is provided on the second wheel disc (712); the arc groove (714) extends in an arc shape to the circumference of the second wheel disc (712); and both ends of the arc groove (714) are closed; The adjustment structure further comprises a slide bar (73) and a cross bar (74); the slide bar (73) is fixed to a side of the tensioning wheel (72) close to the first wheel disc (711); the slide bar (73) is slidably connected in the linear groove (713); the cross bar (74) is rotatably connected to an end of the slide bar (73) away from the tensioning wheel (72); and the other end of the cross bar (74) is slidably connected in the arc groove (714); A rotating wheel (75) is fixed to one end of the cross bar (74) away from the slide bar (73), and the rotating wheel (75) is rotatably arranged in the arc groove (714); The first wheel disc (711) is provided with a limiting hole (715), the limiting hole (715) is internally threadedly connected to a limiting bolt (76), and one end of the limiting bolt (76) is tightly pressed against the inner wall of the second wheel disc (712) when being tightened.

2. A fire hydrant pipe cutting device according to claim 1, characterized in that: The driving mechanism (5) comprises: A servo motor (51), wherein the servo motor (51) is fixed to the outer side of the housing of the cutting machine (4); A transmission wheel (52), wherein two transmission wheels (52) are provided, and one of the transmission wheels (52) is fixed on an output shaft of the servo motor (51); A transmission belt (53), wherein the transmission belt (53) is transmission-sleeved between the two transmission wheels (52); A rotating shaft (54) is fixedly connected through the cutter (41) and another transmission wheel (52).

3. A fire hydrant pipe cutting device according to claim 1, characterized in that: The transmission structure comprises a reduction gear set (6), the reduction gear set (6) comprising a plurality of gears, the reduction gear set (6) comprising a first gear (61) and a second gear (62), the first gear (61) being fixedly sleeved on a rotating shaft (54), the second gear (62) being meshed with the first gear (61), and the diameter of the second gear (62) being larger than the diameter of the first gear (61), the second gear (62) being transmission-connected to a fixed wheel (71) via a transmission shaft, the other end of the transmission shaft passing through the fixed wheel (71) and being rotationally connected to a connecting rod fixed to a housing of the cutting machine (4).

4. A fire hydrant pipe cutting device according to claim 3, characterized in that: A plurality of the tensioning wheels (72) are all fixedly sleeved with flexible sleeves on their circumferences, the flexible sleeves being made of rubber material, and gaps being present between both ends of the flexible sleeves and the inner side walls of the first wheel disc (711) and the second wheel disc (712).

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