Cutter apparatus

Abstract: A cutter robot (1) used to operate in a horizontal pipe (23) and having a horizontally extending main body (6), a stand means (2 - 5) to support said main body, and a head bearing a rotary grinder assembly (16), wherein said head comprises: (i) a motor (15) having an upward output shaft to bear the grinder assembly (16) locked about its end, (ii) two holders (11, 13), and (iii) two vertically disposed piston cylinders (12, 14), which are arranged such that the first piston cylinder (12) connected to the main body (6) has an upward piston rod (12a), and the first holder (11) supported at the end of the upward piston rod (12a) of the first piston cylinder (12) holds the second piston cylinder (14), and the second holder (13) supported at the end of the downward piston rod (14a) of the second piston cylinder (14) holds the motor (15).

Description: The present invention relates to a rotary cutter apparatus equipped with a rotary grinder which can be used conveniently and effectively at a certain step in a pipe repair operation wherein a lining material is applied to the inner wall of a pipe which has a second pipe branching therefrom. The cutter apparatus of the present invention is preferably an on-the-sleigh robot having a rotary grinder disk which can be shifted vertically, and can cut with its side surface as well as its top and bottom surfaces. When an underground pipe, such as a pipeline or a passageway, becomes defective or too old to perform properly, the pipe is repaired and restored without digging the earth to expose the pipe and disassembling the sections of the pipe. This non-digging method of repairing an underground pipe has been known and practiced commonly in the field of civil engineering. Typically, the method is disclosed by Japanese Provisional Patent Publication (Kokai) No. 60-242038. According to this publication, this method of pipe repair comprises inserting a sufficiently long tubular flexible liner bag into the pipe to be repaired by means of a pressurized fluid, such as air or water. The tubular liner bag is made of a flexible resin-absorbent material impregnated with a thermosetting resin, and has its outer surface covered with an impermeable plastic film. More particularly, according to the publication, the tubular flexible liner bag is closed at one end and open at the other; the tubular flexible liner bag is first flattened, then the closed end of the tubular liner bag is tied to a control rope; the open end of the tubular liner bag is made to gape wide and hooked (anchored) at the end of the defective or old pipe in a manner such that the wide-opened end of the liner completely and fixedly covers and closes the pipe end; a portion of the liner is pushed into the pipe; then, pressurized fluid is applied to the said portion of the tubular liner such that the fluid urges the tubular liner to enter the pipe. Since one end of the tubular liner is hooked at the end of the pipe, it remains there while the rest of the flexible liner bag is turned inside out as it proceeds deeper in the pipe. (Hereinafter, this manner of insertion shall be called "everting".) When the entire length of the tubular liner bag is everted (i.e., turned inside out) into the pipe, the control rope holds the closed end of the tubular liner bag to thereby control the length of the tubular liner in the pipe. Then, the everted tubular liner is pressed against the inner wall of the pipe by the said pressurized fluid, and the tubular flexible liner is hardened as the thermosetting resin impregnated in the liner is heated, which is effected by heating the fluid filling the tubular liner bag by means of hot steam, etc. It is thus possible to line the inside wall of the defective or old pipe with a rigid liner without digging the ground and disassembling the pipe sections. When, however, this method is applied to a pipe having a second pipe branching out from it, like the pipe 123 shown by cross section in Fig. 10 the accompanying drawings, it is necessary to cut off that portion of the liner 125 which closes the branch pipe 124. To do so, an on-the-sleigh robot (cutter apparatus), like the robot 101 shown in Fig. 11 of the accompanying drawings, having a hole saw type rotary grinder disk 116 of a diameter corresponding to the size of the branch pipe 124 is conventionally employed, which is brought in the main pipe 123 and operated to cut and remove that portion of the the liner 125 which closes the opening of the branch pipe 124, so as to establish communication between the main pipe 123 and the branch pipe 124. As shown, the rotary grinder disk 116 is topped with a conical grinding cutter. The on-the-sleigh robot 101 as described above comprises a robot main body 106, which is mounted on a pair of sleigh boards and thus capable of sliding to move in the main pipe. On the robot main body 108 are mounted a flash light 107 and a TV camera for monitoring. Further, a vertical piston cylinder 112 having a piston rod is connected to the head of the robot main body 108, and a motor 115 is supported on the piston rod in a manner such that the motor 115 can be shifted up and down, and the rotary grinder disk 116 is locked about the end of the output shaft of the motor 115. Thus, in an operation of removing that round portion of the liner 125 which closes the branch pipe, the on-the-sleigh robot 101 is first introduced into the main pipe 123 and brought to the optimum position, as shown in Fig. 11, and then the motor 115 is started and the piston cylinder 112 is operated to raise the turning grinder disk 116 toward the liner 125. Thus, the obstacle portion of the liner 125 is ground off by the grinder disk 116, and the communication between the main pipe 123 and the branch pipe 124 is resumed. Now, in the conventional on-the-sleigh robot 101 shown in Fig. 11, the maximum distance through which the grinder disk 116 can move vertically is limited by the stroke length through which the piston cylinder 112 can reciprocate its piston rod, so that depending on the diameter of the main pipe 123, it can happen that the grinder disk 116 fails to completely grind off the obstacle portion of the liner 125. As shown in Fig. 10, the smaller the radius r (D/2) of the main pipe 123 (that is, the greater the curvature ), the greater will be the warpage height H of the obstacle portion of the liner 125; so that in the case of a pipe of a relatively small diameter, this problem is more liable to occur. The present invention was made in view of this problem, and it is therefore an object of the invention to provide a cutter apparatus which can provide the grinder with a sufficient amount of vertical movement. Attention is also drawn to WO83/03457, which discloses a remotely controllable travelling robot for operation inside a pipe or bore-hole, which has a tool mounting assembly which is rotatable in a support structure about a longitudinal axis. The support structure is mounted on a pair of skids by means of a hydraulically driven elevator mechanism including rams mounted on the skids which lift the support structure to a required height so as to place the longitudinal axis approximately in coincidence with the axis of the pipe or bore-hole. A tool mounting head forming part of the tool mounting assembly is itself hydraulically powered for tilting about a transverse axis and for moving transversely relative to the longitudinal axis along a transverse bar fixed in a tool mounting assembly casing. The present invention provides a cutter apparatus for use in a horizontal pipe, said apparatus having a horizontally extending main body, a stand means to support said main body, and a head bearing a rotary grinder assembly, wherein said head comprises: (i) a motor having an upward output shaft to turn said grinder assembly locked about the end thereof, (ii) a plurality of holders, and (iii) as many vertically disposed piston cylinders as said holders; which are arranged such that a first cylinder is connected to said main body, a second cylinder is held by a first holder which is supported by a piston rod of the first cylinder, and said motor is held by the last one of the holders which is supported by a piston rod of the last one of the cylinders; characterized by comprising at least two parallel piston cylinders arranged such that each one has its piston rod extending in the direction opposite to the direction of the adjacent piston cylinder(s), and in that one piston rod is provided with a holder to which the adjacent cylinder is connected. A preferred embodiment of the cutter apparatus of the invention comprises two piston cylinders and two holders, and the first piston cylinder connected to said main body has an upward piston rod, and the first holder supported at the end of said upward piston rod of the first piston cylinder holds the second piston cylinder, and the second holder supported at the end of a downward piston rod of the second piston cylinder holds the motor. The cutter apparatus of the invention may comprise more than two said holders and more than two said piston cylinders, which are arranged such that a first cylinder is connected to said main body, a second cylinder is held by a first holder which is supported by a piston rod of the first cylinder, a third cylinder is held by a second holder which is supported by a piston rod of the second cylinder, and so on if there are more than three cylinders and holders, and said motor is held by the last one of the holders which is supported by a piston rod of the last one of the cylinders. According to the invention, the amount of possible vertical displacement of the first holder relative to the main body is determined by the stroke of the first piston cylinder, and the amount of possible vertical displacement of the second holder relative to the first holder is determined by the stroke of the second piston cylinder, and so on, so that the amount of possible vertical displacement of the grinder assembly, which is supported on the last one of the holders, relative to the main body is the sum of the respective strokes of all the piston cylinders. Accordingly, the amount of vertical displacement of the grinder assembly of the present embodiment is increased over the prior art by the amount equal to sum of the strokes of the piston cylinders minus the stroke of the first piston cylinder; hence it is now possible to provide the grinder assembly with a sufficient amount of vertical movement, enabling the operator to conduct a more accurate and effective cutting operation. The invention will be further described, by way of example only, with reference to the accompanying drawings, in which: Fig. 1 is a side view of an on-the-sleigh robot according to an embodiment of the invention; Fig. 2 is a side view of the on-the-sleigh robot as it is traveling in a main pipe; Fig. 3 is a side view of the on-the-sleigh robot as it is immobilized in the main pipe; Fig. 4 is a vertical cross section of the main and branch pipes taken along the center line of the main pipe, wherein the liner is being cut by the on-the-sleigh robot of the invention; Fig. 5 is a vertical cross section similar to Fig. 4, showing how the liner is cut off; Fig. 6 is a vertical cross section similar as Fig. 4 to show a further step of the cutting operation; Fig. 7 is a vertical cross section similar as Fig. 4 to show a still further step of the cutting operation; Fig. 8 is a vertical cross section similar as Fig. 4 to show a subsequent step of the cutting operation; Fig. 9 is a vertical cross section similar as Fig. 4 after the obstacle portion of the liner is cut off completely; Fig. 10 is a vertical cross section of main and branch pipes taken on a plane normal to the center line of the main pipe; and Fig. 11 is a side view of a conventional on-the-sleigh robot operating in a main pipe. As shown in Fig. 1, an on-the-sleigh robot 1 of the present embodiment has a main body 6, which has three pairs of parallel legs 3, 3, 4, 4, 5, 5, which are pivotally shod with a sleigh 2, and a flash light 7 and a TV camera 8 for monitoring are fixed on the back of the main body 6. Now, each pair of the parallel legs 3, 4, 5, are parallel to other pairs as well, and are each pivotally connected to the respective sides of the main body 6 at the locations indicated by the letters a, b, and c, which are alongside the center line of the generally cylindrical main body 6. The rearmost pair of the legs 5, 5 extend beyond the connection points c, and the lengths of the legs 5, 5 are such that the pivotal point c is the middle of the legs 5, 5. In other words, the distance L1 from the pivotal point c to the upper end of the leg 5 is equal to the distance L2 from the pivotal point c to the lower end of the same (L1 = L2). A pair of hydraulically operated piston cylinders 9, 9 are horizontally welded to the underside of the main body 6, one cylinder on either side, and each piston cylinder 9 is provided with a piston rod 9a which reciprocates therethrough. On either side, the embossed front end of the piston rod 9a is slidably caught in a slit hole 3a made in the leg 3, and the embossed rear end of the piston rod 9a is also slidably caught in a slit hole 4a made in the leg 4. Along the center line of the main body 6 of the on-the-sleigh robot 1 lies a thick slider rod 10, which is capable of sliding along the center line when driven hydraulically, as indicated by the double-pointed arrow A in Fig. 1, and is also capable of rotating about the center line, as indicated by the curved arrow B. At the front end of the slider rod 10 is connected a hydraulically operated first piston cylinder 12, whose upward piston rod 12a supports a first holder 11, which is connected at the end of the rod 12a, so that the first holder 11 is vertically shifted relative to the first piston cylinder 12. The first holder 11 holds a second hydraulically operated piston cylinder 14, whose downward piston rod 14a supports a second holder 13, which is connected at the end of the rod 14a, so that the second holder 13 is also vertically shifted relative to the second piston cylinder 14. The second holder 13 holds an hydraulically operated motor 15, and a grinder assembly 16 is locked about the end of the upward output shaft of the motor 15. This grinder assembly 16 is constructed by sandwiching a support disk 16b between an upper sanding plate 16a and a lower sanding plate 16a (which are arranged in a vertical row along the motor shaft as shown in Fig. 1). The sanding plates 16a, 16a have their abrasive flat faces exposed and also the support disk 16b has its abrasive lateral face exposed between the two sanding plates 16a. A tapered reamer 16c is provided to form the spire of the assembly rising from the middle of the upper sanding plate 16a. This reamer 16c, the sanding plates 16a, and the support disk 16b are assembled such that they can be detached axially from the motor shaft. At the rear end of the robot main body 6 are connected three hydraulic hoses 17 and an electric cord 18. Also, an hydraulic hose 19 and an electric cord 20 are connected to the hydraulic motor 15. A pull rope 21 is tied at the front part of the sleigh 2 and another pull rope 22 is tied at the rear part of the sleigh 2. In this embodiment, the hydraulically operated piston cylinders 12 and 14 are employed for causing the grinder assembly 16 to ascend and descend, and the hydraulically operated piston cylinders 9 for causing the legs 3, 4 to tilt and stand upright; however, it is possible to employ other similar means, such as pneumatically operated piston cylinders (air cylinders), in place of the hydraulically operated cylinders. Also, in this embodiment, although a hydraulically operated motor 15 is used as the drive source for the grinder assembly 16, it is possible to employ a pneumatically operated motor or an electric motor in place of the hydraulic motor 15. Next will be described an operation of cutting open a tubular liner closing a branch pipe by means of the on-the-sleigh robot 1 of the present invention, with reference to Figs. 2 through 9. In Figs. 2 and 3, the reference numeral 23 designates an underground main pipe, which is already internally lined with a tubular liner 25 by the conventional lining method described earlier. As shown in Fig. 3, a branch pipe 24 branches off the main pipe 23 to extend toward the ground surface. At this moment, however, the liner 25 is sealing the end of the branch pipe 24, and, therefore, it is necessary to cut off that portion of the liner 25 which closes the end of the branch pipe 24 so as to allow the branch pipe 24 to communicate with the main pipe 23. This cutting operation is conducted by means of the on-the-sleigh robot 1 of the present embodiment in the following manner. As shown in Fig. 2, the on-the-sleigh robot 1 is already brought inside the main pipe 23, and it is being pulled by means of the pull rope 21 in the direction of the arrow (toward the branch pipe 24), while the interior of the main pipe 23, which is lit by the flash light 7, is monitored by means of the TV camera 8. At this moment, the piston rods 9a are displaced rightward, as seen in Fig. 2, to the maximum degree so that the legs 3, 4, 5 are all tilted quite low and the upper ends of the legs 5 are brought down sufficiently away from the ceiling of the lined main pipe 23 to allow smooth movement of the on-the-sleigh robot 1 inside the main pipe 23. Also, as shown in Fig. 2, while the on-the-sleigh robot 1 is in transit, the piston rod 12a is kept withdrawn into the first piston cylinder 12, and the piston rod 14a is kept thrust out from the second piston cylinder 14, so that the grinder assembly 16 is disposed at its lowest possible position. Now, when the on-the-sleigh robot 1 in this state arrives at a desired position, as shown in Fig. 3, where the grinder assembly comes under that portion of the tubular liner 25 which is closing the branch pipe 24, pulling of the on-the-sleigh robot 1 is ceased. Next, the hydraulic piston cylinders 9 on either side of the main body 6 are driven to displace their respective piston rods 9a forward (leftward as seen in Fig. 3), whereupon the main body 6 undergoes a parallel motion with the legs 3, 4, 5 oscillating backward (clockwise as viewed in Fig. 3) about the respective pivotal points d, e, f, until the upper ends of the legs 5 are pressed against the ceiling of the main pipe 23 lined with the tubular liner 25. With the upper ends of the legs 5 thus caught by the ceiling of the main pipe 23, the on-the-sleigh robot 1 is immobilized at the desired location as shown in Fig. 3. As described above, the legs 3, 4, 5 are pivoted on the main body 6 at locations alongside the center line of the main body 6, and the distance L1 from the pivotal point c to the upper end of the leg 5 is equal to the distance L2 from the pivotal point c to the lower end (L1 = L2), so that the main body 6 as it is raised by the pivoting of the legs 3, 4, 5 assumes a position roughly at the same level as the center line of the main pipe 23. When the on-the-sleigh robot 1 is prepared in the main pipe 23 as described above, the hydraulic motor 15 is driven to turn the grinder assembly 16. Then, the first hydraulic cylinder 12 is driven such that its rod 12a is gradually thrust upward, as shown in Fig. 4, whereupon the first holder 11, the second piston cylinder 14, the second holder 13, and the hydraulic motor 15 together with the grinder assembly 16 are raised in one body, and as a result the tapered reamer 16c of the rotating grinder assembly 16 bores a small hole in the tubular liner 25. Eventually, the maximum amount of the rod 12a is thrust out, and then the rod 12a is locked thus. Next, the second hydraulic cylinder 14 is driven such that the already fully thrust out piston rod 14a is gradually withdrawn. Thereupon, the second holder 13 and the hydraulic motor 15 supported thereby and the grinder assembly 16 are together raised relative to the first holder 11, and as a result, the abrasive top-side face of the upper sanding plate 16a grinds through the thickness of the tubular liner 25, and eventually there is made in the tubular liner 25 a hole 25a which has a diameter equal to that of the sanding plate 16a, as shown in Fig. 5. Next, the slider rod 10 is displaced forward in the main body 6 so that the grinder assembly 16 is shifted forward (leftward as viewed in Fig. 6), and then the second hydraulic cylinder 14 is driven to thrust down its rod 14a, whereupon the abrasive bottom-side face of the lower sanding plate 16a grinds through the thickness of the tubular liner 25, and as a result there is made a bigger hole 25b in the tubular liner 25, as shown in Fig. 7. Thus, as this vertical and sideward movement of the grinder assembly 16 is repeated, a desired hole is cut open in the tubular liner 25 by the upper and lower sanding plates 16a alternately, and the remnant burrs are removed as they are ground by the abrasive lateral face of the support disk 16b of the grinder assembly 16, as shown in Fig. 8. More particularly, with reference to Fig. 8, the side face of the support disk 16b of the grinder assembly 16 is pressed against the ground edge of the tubular liner 25 (inner periphery of the hole 25c) and moved laterally (forward, backward, and sideways) until all the burrs of the tubular liner 25 are ground off by the lateral face of the support disk 16b; as a result, a (elliptical) hole 25d is made in the tubular liner 25 which is congruent and coincident with the end hole of the branch pipe 24, as shown in Fig. 9. Thus, the branch pipe 24 communicates with the main pipe 23 via this hole 25d. Now, as described above, in this embodiment, the amount of possible vertical displacement of the first holder 11 relative to the main body 6 is determined by the stroke of the first piston cylinder 12, and the amount of possible vertical displacement of the second holder 13 relative to the first holder 11 is determined by the stroke of the second piston cylinder 14; therefore, the amount of possible vertical displacement of the grinder assembly 16 supported on the second holder 14 relative to the main body 6 is the sum of the respective strokes of the first piston cylinder 12 and the second piston cylinder 14. Accordingly, the amount of vertical displacement of the grinder assembly 16 of the present embodiment is increased over the prior art by the amount equal to the stroke of the second piston cylinder 14; hence it is now possible to provide the grinder assembly 16 with a sufficient amount of vertical movement, enabling the operator to conduct a more accurate and effective cutting operation. As is clear from the above description, according to this embodiment, there is proposed an on-the-sleigh robot having a horizontally extending main body, legs shod with the sleigh, and a head portion equipped with a rotary grinder assembly, wherein this head portion includes a hydraulic motor having an upward output shaft to bear the grinder assembly about its end thereof, a plurality of holders, and a plurality of vertically held hydraulic piston cylinders, arranged such that the first piston cylinder connected to the end of a slider rod extending from the main body has an upward piston rod, and the first holder supported at the end of the upward piston rod of the first piston cylinder holds the second piston cylinder, and the second holder supported at the end of the downward piston rod of the second piston cylinder holds the motor, so that the operator can vertically displace the grinder assembly by two steps and to a greater height relative to the main body of the on-the-sleigh robot. Thus, the cutting operation will be conducted at a higher efficiency and in a shorter time. While the invention has been described in its preferred embodiment, it is to be understood that modifications will occur to those skilled in the art without departing from the scope of the invention.

Claims: A cutter apparatus (1) for use in a horizontal pipe (23), said apparatus having a horizontally extending main body (6), a stand means (2-5) to support said main body, and a head bearing a rotary grinder assembly (16), wherein said head comprises: (i) a motor (15) having an upward output shaft to turn said grinder assembly (16) locked about the end thereof, (ii) a plurality of holders (11,13), and (iii) as many vertically disposed piston cylinders (12,14) as said holders; which are arranged such that a first cylinder (12) is connected to said main body (6), a second cylinder (14) is held by a first holder (11) which is supported by a piston rod (12a) of the first cylinder (12), and said motor (15) is held by the last one (13) of the holders which is supported by a piston rod (14a) of the last one of the cylinders (14); characterized by comprising at least two parallel piston cylinders (12,14) arranged such that each one has its piston rod (12a,14a) extending in the direction opposite to the direction of the adjacent piston cylinder(s), and in that one piston rod is provided with a holder to which the adjacent cylinder is connected. A cutter apparatus as claimed in claim 1, characterized by comprising two piston cylinders (12,14) and two holders (11,13), and the first piston cylinder (12) connected to said main body (6) has an upward piston rod (12a), and the first holder (11) supported at the end of said upward piston rod (12a) of the first piston cylinder (12) holds the second piston cylinder (14), and the second holder (13) supported at the end of a downward piston rod (14a) of the second piston cylinder (14) holds the motor (15). A cutter apparatus as claimed in claim 1, characterized by comprising more than two said holders and more than two said piston cylinders, which are arranged such that a first cylinder is connected to said main body (6), a second cylinder is held by a first holder which is supported by a piston rod of the first cylinder, a third cylinder is held by a second holder which is supported by a piston rod of the second cylinder, and so on if there are more than three cylinders and holders, and said motor (15) is held by the last one of the holders which is supported by a piston rod of the last one of the cylinders.

Inventors: ENDOH SHIGERU, KAMIYAMA TAKAO, YOKOSHIMA YASUHIRO, ENDOH, SHIGERU, KAMIYAMA, TAKAO, YOKOSHIMA, YASUHIRO
Applicants: GET INC, SHONAN GOSEI JUSHI SEISAKUSHO, YOKOSHIMA & CO, GET INC., SHONAN GOSEI - JUSHI SEISAKUSHO K.K., YOKOSHIMA & COMPANY
Application year: 1995
Main classification: F16L55
IPC codes: B23B41, B29C63, F16L55