Offset support wheels

Abstract

To provide an in-pipe moving device which is lightweight so as to be moved by fluid pressure, that is, which has a simple structure, which can pass through a number of elbows, and which has high capability of stepping over an obstacle in a pipe.SOLUTION: An offset support wheel 1 includes a spherical wheel 10, and an axle 16 passing through a center of the wheel 10, the axle 16 being such that the wheel 10 rotates around a center axis of the axle 16; wherein the wheel 10 includes, in a direction of the axle 16, a first semi-spherical part 12 in a substantially semi-spherical shape, a second semi-spherical part 14 in a substantially semi-spherical shape, positioned opposite to the first semi-spherical part 12, and a central member 18 positioned between the first hemispherical part 12 and the second hemispherical part 14; and wherein the tether 100 is constrained in a traveling direction of the offset support wheel 1, at a position offset from the axle 16 of the center member 18.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a wheel that moves inside a pipe, and in particular to a wheel that can easily pass through bends in the pipe. [Background technology]

[0002] Mobile devices that travel inside pipes are used to inspect and maintain lifelines such as gas and water lines, and pipes used in industrial plants. The mobile devices pull power lines that supply power from an external power source, signal lines that transmit operating signals for the mobile devices, signal lines that transmit information from cameras and sensors at the tip to the outside, and tethers (guiding wires) that bundle together fluid tubes, etc.

[0003] However, when the in-pipe mobile device passes through several elbows (bends), the tether rubs against the elbows, generating friction. According to Euler's belt theory, the friction force on the tether increases exponentially with the sum of the elbow bend angles. Therefore, passing through several elbows creates a significantly large resistance, hindering the in-pipe mobile device's advance.

[0004] In order to reduce the traction resistance of a tether pulled through a pipe, an in-pipe mobile device with wheels attached radially has been proposed (see Patent Document 1). When the wheels are arranged radially as in Patent Document 1, one of the wheels will come into contact with the inner wall of the pipe regardless of the orientation of the tether, allowing the device to travel with reduced resistance. However, to create such a device, it is necessary to arrange multiple wheels in all directions, at least three or more. As a result, the in-pipe mobile device becomes heavy, and the diameter of the wheels must be at least half the diameter of the pipe, which poses the problem of reduced ability to traverse obstacles in the pipe. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-84728 Summary of the Invention [Problem to be solved by the invention]

[0006] The invention disclosed in Patent Document 1 is based on the premise that the in-pipe moving device will be drawn out using a retrieval member, and the retrieval member must be drawn into the pipe in advance. However, in the case of piping where the retrieval member cannot be drawn in advance, there is a strong demand for inspection and maintenance to be performed using an in-pipe moving device that moves within the pipe using fluid pressure.

[0007] Therefore, an object of the present invention is to provide an in-pipe moving device that is lightweight, i.e., has a simple structure so that it can be moved by fluid pressure, can pass through multiple elbows, and has a high ability to overcome obstacles in the piping. [Means for solving the problem]

[0008] In order to solve the above problems, the offset support wheel according to a first aspect of the present invention is an offset support wheel 1 comprising a spherical wheel 10 and an axle 16 that passes through the center of the wheel 10, such that the wheel 10 rotates around the central axis of the axle 16, as shown in Figures 1 and 2, and the wheel 10 comprises, in the direction of the axle 16, a first hemispherical portion 12 that is approximately hemispherical, a second hemispherical portion 14 that is approximately hemispherical and located opposite the first hemispherical portion 12, and a central member 18 that is located between the first hemispherical portion 12 and the second hemispherical portion 14, and a tether 100 that is restrained in the traveling direction of the offset support wheel 1 at a position offset from the axle 16 of the central member 18.

[0009] With this configuration, the offset support wheel that pulls the tether pulls the tether at a position offset from the axle. Therefore, in straight pipe sections, the weight of the tether causes the tether to be positioned downward, and the center member side of the wheel (the side with the largest diameter) contacts the inner surface of the pipe and rotates around the central axis, allowing for smooth wheel rotation. Furthermore, in elbow sections, the force pulling the tether causes the tether to be positioned inside the elbow. Therefore, the center member side of the wheel (the side with the largest diameter) contacts the inner surface of the elbow and rotates around the axle, allowing for smooth wheel rotation to pass through the elbow. Furthermore, the offset support wheel has a simple structure in which the tether is pulled at a position offset from the axle of the spherical wheel, allowing for lightweight manufacturing. Furthermore, because the wheel is spherical overall, it can be made larger than the pipe diameter, improving its ability to traverse obstacles in the pipe. Furthermore, thrust is easily generated when this spherical wheel is subjected to fluid pressure.

[0010] In the offset support wheel 2 according to the second aspect of the present invention, as shown in Fig. 3, the central member 28 has an outer shape that forms a smooth spherical surface with the first hemispherical portion 12 and the second hemispherical portion 14. With this configuration, the central member has an outer shape that forms a smooth spherical surface with the first hemispherical portion and the second hemispherical portion, so the wheel becomes nearly spherical, and the offset support wheel easily rotates with the tether positioned downward no matter what angle it is tilted at.

[0011] In the offset support wheel 1 according to the third aspect of the present invention, as shown in Fig. 1, for example, the central member 18 has an outer shape that is smaller than the radius of the approximately hemispherical shape of the first hemispherical portion 12 and the second hemispherical portion 14. With this configuration, even if the central member has a small dimension and is shaped to form a groove-like portion, the wheel as a whole forms a spherical shape, so the offset support wheel can easily rotate with the tether positioned downward no matter what angle it is tilted at.

[0012] As shown in Figures 4 and 5, the coupled offset support wheel 3 according to the fourth aspect of the present invention comprises a first offset support wheel 4 which is the offset support wheel of any one of the first to third aspects, a second offset support wheel 5 which is a spherical wheel 50, and an axle 16 which passes through the center of the wheel 50 and around which the wheel 50 rotates, the wheel 50 having, in the direction of the axle 16, a first hemispherical portion 12 which is substantially hemispherical, a second hemispherical portion 14 which is substantially hemispherical and located on the opposite side of the first hemispherical portion 12, and a central member 58 which is located between the first hemispherical portion 12 and the second hemispherical portion 14, and an elastic rod 110 which couples the first offset support wheel 4 and the second offset support wheel 5, the elastic rod 110 coupling the central member 48 of the first offset support wheel 4 and the central member 58 of the second offset support wheel 5 at positions offset from the axle 16.

[0013] With this configuration, the first offset support wheel and the second offset support wheel are connected by an elastic rod. Therefore, when the wheel passes through the elbow, the elastic rod is bent, and a force that tries to return the wheel to a straight line acts on the first offset support wheel and the second offset support wheel. In other words, a reaction force acts on the first offset support wheel and the second offset support wheel from the inner wall of the pipe toward the center of the spherical wheel. Meanwhile, because the elastic rod is connected at a position offset from the center of the wheel (axle), the offset support wheel changes its position so that the reaction force and the force from the elastic rod are on the same line, i.e., so that the position where the elastic rod is connected is on the inner wall of the pipe closest to the bending center of the elbow. Therefore, the center member side of the wheel (the side with the largest diameter) contacts the inner surface of the elbow and rotates around the axle, allowing the wheel to pass through the elbow with smooth rotation.

[0014] 4 and 5, the coupled offset support wheel 3 according to the fifth aspect of the present invention has a piping condition monitoring device 120 on the central member 48 of the first offset support wheel 40, and the tether 100 includes a communication line for transmitting signals to the piping condition monitoring device 120 and a power line for supplying power to the piping condition monitoring device 120. With this configuration, the coupled offset support wheel, which can easily move inside the pipe, is provided with the piping condition monitoring device, and the tether allows signal communication with the outside and power supply from the outside, making it easy to inspect the inside of the pipe.

[0015] As shown in FIG. 7(A), a sixth aspect of the present invention relates to a third offset support wheel (7), which includes a spherical wheel (70) and an axle (16) that passes through the center of the wheel (70) and rotates around the central axis of the axle (16). The wheel (70) includes a third offset wheel (7) that includes, in the direction of the axle (16), a substantially hemispherical first hemispherical portion (12), a substantially hemispherical second hemispherical portion (14) located opposite the first hemispherical portion (12), and a central member (78) located between the first hemispherical portion (12) and the second hemispherical portion (14). An elastic rod (110) is fixed on the outer periphery of the central member (78) of the third offset support wheel (7) between the first offset support wheel (4) and the second offset support wheel (5).

[0016] With this configuration, the elastic rod is fixed on the outer periphery of the third offset support wheel, and its ends are connected to the first and second offset support wheels. This means that the spring force of the elastic rod, which tries to return it to a straight line, acts on the first and second offset support wheels, while a force in the opposite direction acts on the third offset support wheel. As a result, when passing through an elbow, these forces cause the connected offset support wheel to change position so that the third offset support wheel is pressed against the outside of the bend in the elbow. This allows the center member side of the wheel (the side with the largest diameter) to contact the inner surface of the elbow and rotate around the axle, allowing for smooth wheel rotation when passing through the elbow. [Effects of the Invention]

[0017] According to the present invention, the offset support wheel includes a spherical wheel and an axle that passes through the center of the wheel and rotates around the central axis of the axle. The wheel includes a first hemispherical portion that is approximately hemispherical in the axle direction, a second hemispherical portion that is approximately hemispherical and located opposite the first hemispherical portion, and a central member that is located between the first and second hemispherical portions. The tether is constrained in the traveling direction of the offset support wheel at a position offset from the axle of the central member, so that the central member side of the wheel contacts the inner surface of the pipe and rotates around the axle, allowing for smooth wheel rotation. Furthermore, in the coupled offset support wheel, the spring force of the elastic rod causes the central member side of the wheel to contact the inner surface of the elbow and rotate around the axle, allowing for smooth wheel rotation to pass through the elbow. Therefore, an in-pipe mobile device can be provided that has a simple structure, can pass through multiple elbows, and has a high ability to traverse obstacles in the pipe. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is a perspective view of one embodiment of an offset support wheel according to the present invention. [Figure 2] FIG. 2 is a side view of the offset support wheel shown in FIG. [Figure 3] FIG. 3 is a perspective view of a modified example of the offset support wheel shown in FIG. [Figure 4] FIG. 4 is a perspective view of one embodiment of the interlocking offset support wheels according to the present invention, an example having two wheels. [Figure 5] 5 is a side view of the coupled offset support wheel shown in FIG. 4. FIG. [Figure 6] FIG. 6 is an explanatory diagram of the operation of the coupled offset support wheel shown in FIG. 4 when it passes through an elbow. [Figure 7] FIG. 7 is a perspective view of one embodiment of an articulated offset support wheel according to the present invention, illustrating the operation of an example offset support wheel having three wheels as it passes through an elbow. [Figure 8] FIG. 8 is an explanatory diagram of the operation when the coupled offset support wheel shown in FIG. 7 passes through the reducer. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In each drawing, identical or corresponding devices are designated by the same reference numerals, and redundant description will be omitted. First, an offset support wheel 1 according to the present invention will be described with reference to FIG. 1. The offset support wheel 1 is a wheel that can be used as an in-pipe moving device that moves within a pipe using fluid pressure. The offset support wheel 1 includes a spherical wheel 10 and an axle 16 that passes through the center of the wheel 10. The wheel 10 is rotatable around the axle 16. The wheel 10 includes a first hemispherical portion 12 that is approximately hemispherical, a second hemispherical portion 14 that is approximately hemispherical, and a central member 18 located between the first hemispherical portion 12 and the second hemispherical portion 14. The first hemispherical portion 12 and the second hemispherical portion 14 are typically plane-symmetrical, but this is not a limitation. At least the first hemispherical portion 12 and the second hemispherical portion 14 are rotatable around the axle 16. The central member 18 may be rotatable around the axle 16, or may be fixed to the axle 16. A through hole 19 is formed in the central member 18 in a direction perpendicular to the axle that passes through it, at a position offset from the axle 16. A tether 100 is inserted into the through hole 19, and movement in the insertion direction is constrained. The tether 100 may be fixed to the through hole 19, or may be rotatable around the longitudinal axis. Instead of the through hole 19, a hole may be used in which the tether 100 is inserted and constrained, but does not pass through.

[0020] The first hemispherical portion 12 and the second hemispherical portion 14 are substantially hemispherical. Here, "substantially hemispherical" includes cases where the central angle is less than 180°, as compared with a hemisphere having a central angle of 180°. For example, the central angle may be 90°, 120°, 150°, 170°, or any angle between these. The first hemispherical portion 12 and the second hemispherical portion 14 are symmetrically arranged with the central member 18 in between, resulting in a spherical wheel 10. Here, "spherical" may refer to a perfect sphere, or a shape other than a perfect sphere, such as when the central member 18 sandwiched between the substantially hemispherical first hemispherical portion 12 and the second hemispherical portion 14 has a small outer periphery that forms a groove, as shown in FIG. 1 . The outer periphery of the central member 18 is not limited to a circle but may be polygonal. Alternatively, the outer periphery may not have a continuous surface and may be formed, for example, by multiple rod members. When formed of a rod member, the through-hole 19 may not be formed, and the tether 100 may be restrained by the rod member.

[0021] The offset support wheel 10 has an outer diameter slightly smaller than the inner diameter of the pipe used as an in-pipe moving device, so that it can be inserted into the pipe and moved within the pipe by applying fluid pressure from one side. It can also pass through obstacles such as protruding welds within the pipe. In other words, because it is spherical, it can have an outer diameter that is approximately the same as the inner diameter of the pipe.

[0022] As shown more clearly in the side view of FIG. 2 , in the offset support wheel 1, the tether 100 is offset from the axle 16 of the central member 18. That is, it is offset from the center of rotation of the wheel 10. Because of the offset, when the wheel 10 attempts to pass through an elbow while pulling the tether 100, the pulling force on the tether 100 acts on the offset position of the wheel 10, and the position of the wheel 10 that restrains the tether 100 is closer to the point where it contacts the pipe. Therefore, the first hemispherical portion 12 and the second hemispherical portion 14 of the wheel 10 contact the pipe on the central member 18 side, i.e., the side with the largest diameter, and rotate around the axle 16, allowing for smooth wheel rotation. Furthermore, when passing through an elbow, the pulling force of the tether 100 causes the wheel 10 to tilt obliquely so as to be perpendicular to the inner surface of the pipe where the axle 16 is in contact. Because the wheel 10 is spherical, it can easily tilt to any angle. As a result, the first hemispherical portion 12 and the second hemispherical portion 14 on the central member 18 side of the wheel 10 roll along the inner surface of the pipe while rotating around the axle 16. In other words, the wheel can move smoothly. This movement remains the same even if the next elbow bends in a different direction. In other words, the wheel can move smoothly even if there are multiple elbows with different directions.

[0023] As described above, the offset support wheel 1 has a simple structure, i.e., is lightweight, and can be easily advanced through a pipe by blowing air through the pipe with a blower or by flowing liquid through the pipe with a pump. It can also pass through multiple elbows. Furthermore, the wheel 10, i.e., the offset support wheel 1, can have an outer diameter that is approximately the same as the inner diameter of the pipe, allowing it to be made larger, and it has a high ability to overcome obstacles in the pipe. The offset amount is set appropriately depending on the inner diameter of the pipe, the outer diameter of the wheel 10, the radius of curvature of the elbow, etc.

[0024] FIG. 3 shows a perspective view of offset support wheel 2, a variation of offset support wheel 1. In offset support wheel 2, central member 28 has an outer shape that forms a smooth spherical surface with first hemispherical portion 12 and second hemispherical portion 14. A smooth spherical surface may have some steps or grooves at the boundaries between first hemispherical portion 12 and central member 28, and between central member 28 and second hemispherical portion 14, as long as the surface is smooth overall. With this configuration, wheel 20, i.e., offset support wheel 2, is more likely to tilt perpendicular to the inner surface of the pipe with which axle 16 is in contact. In offset support wheel 2, central member 28 is in contact with the inner surface of the pipe and rotates around axle 16 while rolling and moving along the inner surface of the pipe.

[0025] Next, with reference to Figures 4 and 5, a description will be given of a coupled offset support wheel 3 attached to the tip of a tether according to the present invention. The coupled offset support wheel 3 is an example having two wheels, a first offset support wheel 4 and a second offset support wheel 5 having a structure similar to that of the offset support wheel 1 or the offset support wheel 2, which are coupled by an elastic rod 110. The second offset support wheel 5 includes a spherical wheel 50 and an axle 16 passing through the center of the wheel 50. The wheel 50 is rotatable around the axle 16. The wheel 50 includes a first hemispherical portion 12 having a substantially hemispherical shape, a second hemispherical portion 14 having a substantially hemispherical shape, and a central member 58 located between the first hemispherical portion 12 and the second hemispherical portion 14. The first hemispherical portion 12 and the second hemispherical portion 14 are similar to those of the offset support wheel 1. The central member 58 may be rotatable around the axle 16 or may be fixed to the axle 16.

[0026] The first offset support wheel 4 has a wheel 40, similar to the offset support wheel 1. The tether 100 is restrained at an offset position on a central member 48 of the wheel 40. A piping condition monitoring device 120, such as a camera or a sensor, is also provided on the central member 48. Here, a light 122 is provided near the piping condition monitoring device 120, which is a camera, to illuminate the position where the piping condition monitoring device 120 captures an image. In FIG. 4 , two lights 122 are provided on both sides of the piping condition monitoring device 120, but the number and positions of the lights 122 are not limited to this. The piping condition monitoring device 120 may be a camera that captures still images or a camera that captures video as the connected offset support wheel 3 moves. The light 122 may be an LED or other known light. By installing the piping condition monitoring device 120 in this manner, the inner surface of the pipe can be easily inspected. In this embodiment, if a device containing a steel ball (Fig. 5) in a transparent hemisphere is attached to the rear of the front wheel X (Fig. 5), the position of the steel ball in the hemisphere can be monitored with the piping condition monitoring device 120, making it possible to determine the up and down positions of the piping and to make it easier to understand the status of the internal pipe inspection. Note that depending on the piping condition monitoring device 120, such as a sensor, the lighting 122 may not be necessary.

[0027] The power lines that supply power to the piping condition monitoring equipment 120 and the lighting 122, the signal lines that transmit operating signals for the piping condition monitoring equipment 120 and the lighting 122, and the signal lines that transmit information from the piping condition monitoring equipment 120 to the outside are all combined into a tether 100.

[0028] The elastic rod 110 connecting the first offset support wheel 4 and the second offset support wheel 5 is fixed to the central members 48, 58 at a position offset from the axle 16 in the same direction as the offset direction of the tether 100. As shown in Figure 5, the elastic rod 110 may be fixed with a larger offset amount than the tether 100, or conversely, may be fixed with a smaller offset amount.

[0029] With reference to Figure 6, the operation of the coupled offset support wheel 3 attached to the tip of the tether as it passes through an elbow will be described. Figure 6(A) is a plan view of the coupled offset support wheel 3 traveling along the straight pipe section (pipe) 200. The elastic rod 110 becomes straight, and in order to pull the tether 100, the offset support wheels 4 and 5 restrain the tether 100 at a lower position, i.e., closer to the point of contact with the straight pipe section 200. Therefore, the first hemispherical portion 12 and the second hemispherical portion 14 on the side of the center members 48 and 58 of the wheels 40 and 50 come into contact with the straight pipe section 200 and rotate around the axle 16, making it easier for the wheels 40 and 50 to travel.

[0030] FIG. 6(B1) is a front view of the coupled offset support wheel 3 passing through the elbow (pipe) 210. When passing through the elbow 210, the offset support wheels 4 and 5 are pressed against the elbow by fluid pressure, bending the elastic rod 110. This reaction force acts from the elastic rod 110 on the wheels 40 and 50. In addition, a force from the inner wall of the elbow 210 also acts on the wheels 40 and 50. FIG. 6(B2) is a diagram explaining the forces acting on the wheels 40 and 50 as viewed from the direction of travel. The wheels 40 and 50 are spherical, and the force FP from the elbow 210 acts toward the center. The force FR from the elastic rod 110 acts from an offset coupling point, so it is offset from the center. When the force FR from the elastic rod 110 is offset from the center, a rotational moment is generated. As a result, the wheels rotate so that the force FR from the elastic rod 110 and the force FP from the elbow 210 are on the same line, as shown in FIG. 6(C2). That is, the position where the elastic rod 110 is connected becomes closer to the point where it contacts the elbow 210. Therefore, at the elbow 210, the wheels 40, 50 are inclined obliquely so as to be perpendicular to the inner surface of the elbow 210 where the axle 16 contacts. Therefore, as shown in FIG. 6(C1), the first hemispherical portion 12 and the second hemispherical portion 14 of the wheels 40, 50 contact the inner surface of the elbow 210 on the side of the center members 48, 58, and roll on the inner surface of the elbow 210 while rotating around the axle 16, allowing the wheels to move smoothly.

[0031] Next, referring to FIG. 7, a linked offset support wheel 6 will be described as an example of a linked offset support wheel having three wheels. FIG. 7(A) is a schematic front view showing the structure of the linked offset support wheel 6. In the linked offset support wheel 6, the elastic rod 110 connecting the two wheels 40, 50 described as the linked offset support wheel 3 may be attached so as to be wound around the central member 78 of the wheel 70 of the third offset support wheel 7. Like the wheel 10, the wheel 70 has a first hemispherical portion 12 and a second hemispherical portion 14 arranged around the axle 16, with the central member 78 therebetween. The central member 78 has an outer diameter smaller than the outer diameters of the first hemispherical portion 12 and the second hemispherical portion 14 where they meet, and grooves are formed in the first hemispherical portion 12 and the second hemispherical portion 14. The elastic rod 110 is wound around the outer periphery of the central member 78 and is fixed to the outer periphery of the central member 78 at one point where it is wound around. That is, the central member 78 is fixed at a position offset from the axle 16. The outer periphery of the central member 78 may be a ring or other shape, and as long as the elastic rod 110 can be wound around it, it does not have to have a continuous surface, such as being formed from multiple rod members. In the coupled offset support wheel 6, the spring force of the elastic rod 110 generates a force that moves the side wheels 40, 50 downward in FIG. 7(A) and the central wheel 70 upward. Therefore, the position where the elastic rod 110 is coupled is close to the point where it contacts the pipe. Therefore, the first hemispherical portion 12 and the second hemispherical portion 14 on the side of the central member 48, 58, 78 of the wheels 40, 50, 70 contact the pipe, making it easier for the wheels to rotate around the axle 16 and move forward.

[0032] Figure 7(B) is a front view illustrating the state when the linked offset support wheel 6 passes through the elbow. In this case, the elbow is bent in the direction perpendicular to the plane of the paper in Figure 7(A), i.e., horizontally. When the linked offset support wheel 6 enters the elbow, the elastic rod 110 pushes the wheels 40 and 50 on both sides to the outside of the bend, and the center wheel 70 to the inside of the bend.

[0033] FIG. 7(C) is a plan view of the coupled offset support wheel 6 in the state shown in FIG. 7(B) and is a diagram for explaining the forces acting on the wheels 40, 50, and 70. Because each wheel 40, 50, and 70 is spherical, the force acting on the wheels 40, 50, and 70 from the inner surface of the elbow (pipe) is directed toward the center of the wheels, acting downward on the wheels 40 and 50 and upward on the wheel 70. On the other hand, the force acting from the elastic rod 110 is coupled at offset positions by the central members 48, 58, and 78, i.e., acts at the offset positions, acting upward on the wheels 40 and 50 and downward on the wheel 70. Therefore, a moment is generated by the force acting from the inner surface of the pipe and the force acting from the elastic rod 110. As a result, the coupled offset support wheel 6 rotates around the axis in the traveling direction and assumes the position shown in FIG. 7(D). Figure 7(D) is a front view similar to Figure 7(B). That is, the reaction force received from the inner surface of the pipe and the force acting from the elastic rod 110 are aligned on the same line, so that the center member sides of the wheels 40 and 50 on both sides are pressed against the inside of the bend of the elbow, and the center member side of the central wheel 70 is pressed against the outside of the bend of the elbow. In other words, each wheel 40, 50, 70 is positioned perpendicular to the inner surface of the pipe where the axle 16 is in contact. Therefore, as shown in Figure 7(D), the center member sides of the first hemispherical portion 12 and the second hemispherical portion 14 of each wheel 40, 50, 70 are in contact with the inner surface of the elbow, and the wheels roll and move along the inner surface of the elbow while rotating around the axle 16. In other words, the wheels can move smoothly.

[0034] Next, referring to Figure 8, another advantage of the linked offset support wheel 6, that is, its ease of passing through a reducer, will be described. In the linked offset support wheel 6, the wheels 40, 50 on both sides and the central wheel 70 tend to spread apart due to the spring force of the elastic rod 110. Therefore, even in a reducer that spreads from a small diameter to a large diameter, each wheel 40, 50, 70 firmly contacts the inner surface of the reducer (pipe), and the first hemispherical portion 12 and the second hemispherical portion 14 on the side of the central member 48, 58, 78 contact the inner surface of the reducer, and the wheels roll and move along the inner surface of the reducer while rotating around the axle 16. In other words, the wheels can move smoothly. Conversely, even within the reducer where the diameter narrows from large to small, the elastic rod 110 deforms so that it wraps more around the central member 78, similarly bringing it into firm contact with the inner surface of the reducer (piping), and the first hemispherical portion 12 and the second hemispherical portion 14 on the side of the central members 48, 58, 78 come into contact with the inner surface of the reducer, and roll along the inner surface of the reducer while rotating around the axle 16.

[0035] The coupled offset support wheel 6 has three wheels 40, 50, and 70, so that even when placed in a vertical pipe, it is supported by three points and maintains a stable posture. This makes it convenient for inspecting the inside of the pipe using a pipe condition monitoring device 120. The pipe condition monitoring device is preferably installed on the wheel 40 to which the tether 100 is coupled. The offset support wheel may have four or more wheels. In the above description, the elastic rod 110 is wound once around the outer periphery of the central member 78 of the wheel 70 of the third offset support wheel 7. This is because, when using a piano wire or the like that may be plastically deformed by bending as the elastic rod 110, winding the wire once or multiple times ensures a spring force due to its elastic effect. However, it is not necessary for the wheels 40, 50, and 70 to be wound around each other, and it is sufficient if the three wheels 40, 50, and 70 are arranged in the positional relationship shown in Figure 7. For example, if a thin, tightly wound coil spring or a shape memory alloy wire with a superelastic effect is used for the elastic rod 110, it is sufficient to simply fix the elastic rod 110 to the outer periphery of the central member 78.

[0036] As explained above, the offset support wheel of the present invention has a simple structure, can pass through multiple elbows while pulling a tether, and has a high ability to overcome obstacles in the pipe, making it suitable as an in-pipe mobile device for inspection and maintenance, using air flow or fluid flow to move inside the pipe. [Explanation of symbols]

[0037] 1, 2 offset support wheels 3, 6 linked offset support wheels 4. First offset support wheel 5. Second offset support wheel 7. Third offset support wheel 10, 20, 40, 50, 70 wheels 12 First hemisphere 14 Second hemisphere 16 axles 18, 28, 48, 58, 78 central member 100 Tether 110 Elastic Rod 200 Straight pipe section 210 Elbow

Claims

1. An offset support wheel for fluid pressure movement within a pipe, comprising: Spherical wheels and an offset support wheel comprising an axle passing through the center of said wheel, said wheel rotating about a central axis of said axle; The wheel includes, in the axle direction, a first hemispherical portion having a substantially hemispherical shape, a second hemispherical portion having a substantially hemispherical shape located on the opposite side to the first hemispherical portion, and a central member located between the first hemispherical portion and the second hemispherical portion, A tether passes through the central member at a position offset from the axle and is restrained in the direction of travel of the offset support wheel. Offset support wheels.

2. the central member has an outer shape that forms a smooth spherical surface with the first hemispherical portion and the second hemispherical portion; The offset support wheel of claim 1.

3. the central member has an outer diameter that is smaller than the radius of the generally hemispherical shapes of the first and second hemispherical portions; The offset support wheel of claim 1.

4. a first offset support wheel, which is the offset support wheel according to any one of claims 1 to 3; a second offset support wheel, spherical wheels; an axle passing through the center of the wheel, the wheel rotating about a central axis of the axle; a second offset support wheel, the wheel including, in the axle direction, a first hemispherical portion having a substantially hemispherical shape, a second hemispherical portion having a substantially hemispherical shape located opposite the first hemispherical portion, and a central member located between the first hemispherical portion and the second hemispherical portion; an elastic rod connecting the first offset support wheel and the second offset support wheel, the elastic rod connecting the center member of the first offset support wheel and the center member of the second offset support wheel at positions offset from the axle; Articulated offset support wheels.

5. A piping condition monitoring device is provided on the central member of the first offset support wheel; The tether includes a communication line for transmitting signals to the piping condition monitoring device and a power line for supplying power to the piping condition monitoring device; 5. The offset support wheel of claim 4.

6. a third offset support wheel, spherical wheels; an axle passing through the center of the wheel, the wheel rotating about a central axis of the axle; the wheel includes a third offset wheel including, in the axle direction, a substantially hemispherical first hemispherical portion, a substantially hemispherical second hemispherical portion located opposite the first hemispherical portion, and a central member located between the first hemispherical portion and the second hemispherical portion; The elastic rod is fixed on the outer periphery of the central member of the third offset support wheel between the first offset support wheel and the second offset support wheel; 6. The offset support wheel according to claim 4 or 5.

Images