JP2018126899A - Cutter concrete core cutter and method of forming hole - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a concrete core cutter and a method of forming a hole which make it possible to form a hole extending into a cylindrical wall of a concrete structure in a direction other than a radial direction.SOLUTION: A concrete core cutter (10, 10') comprises: a cutter blade (12) consisting of an annular member (16) supporting a plurality of bits; a plurality of axial members (18) separably connected to the annular member and extending in the axial direction of the annular member; radial members (20) each separably connected to the plurality of axial members and extending radially inward of the annular member; and a plurality of other axial members (18') each attachable to the axial member (18), The concrete core cutter (10) in which the other axial members (18 ') are not attached and the concrete core cutter (10') in which the other axial members (18 ') are attached cut a part of the cylindrical wall (104) of the concrete structure and a part of the remainder, respectively, to form a hole (105) in the wall.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a concrete core cutter and a method for forming a hole in a cylindrical wall of a concrete structure having an entrance provided in the ground.

  Prevents damage to sewer pipes, which have lower strength than manholes, when there is relative movement between concrete structures installed in the ground, such as manholes, and sewer pipes connected to them due to live loads or seismic forces. For this reason, the connecting portion between the manhole and the sewer pipe is subjected to a flexible treatment. The flexible treatment is performed by cutting a cylindrical wall (casing) of a manhole to form an annular hole around the sewer pipe, and then filling the annular hole with an elastically deformable water stop material. Is called.

  The manhole wall cutting performed in association with the flexing process is performed by installing a concrete core cutter having a cylindrical casing supporting a plurality of bits in the manhole. However, the diameter of the manhole entrance is relatively small. For this reason, a concrete core cutter has been proposed which is composed of a plurality of casing parts that are separably connected in the circumferential direction (see Patent Document 1 below). According to this, individual housing parts can be carried into the manhole through the entrance of the manhole, and the loaded housing parts can be assembled in the manhole, and then the assembled concrete core cutter is driven to rotate and propelled. By doing so, a hole can be formed in the wall of the manhole.

  By the way, the sewer pipe connected to the cylindrical wall of the manhole may extend in a radial direction of the cylindrical wall, that is, in a radial direction, or may extend in a direction other than the radial direction. In any case, when the hole is formed, the concrete core cutter is disposed on the extension of the sewer pipe in the manhole. However, the length of the sewer pipe extending in the manhole is shorter in the latter case where the sewer pipe extends in a direction other than the radial direction than in the former case where the sewer pipe extends in the radial direction. For this reason, in the latter case, it may not be possible to install a concrete core cutter having a length sufficient to penetrate the wall (length in the axial direction).

JP 2001229554 A

  An object of the present invention is to provide a concrete core cutter and a hole forming method that contribute to forming a hole extending in a direction other than the radial direction in a cylindrical wall of a concrete structure having an entrance provided in the ground. There is to do.

  The present invention relates to a concrete core cutter, wherein the concrete core cutter is a cutter blade made of an annular member that supports a plurality of bits, and the annular member can be deformed into a non-annular shape so as to allow the annular member to be deformed into an annular shape. A cutter blade comprising a plurality of arcuate pieces that are swingably and detachably connected to each other around an axis parallel to the axis of the member, and a separably connected to the annular member in the axial direction of the annular member A plurality of axial members extending, a plurality of radial members detachably connected to the plurality of axial members and extending radially inward of the annular member, and a plurality of other members that can be added to the plurality of axial members The axial direction member is provided.

  According to the present invention, in forming the hole in the wall of the concrete structure, the wall is cut in two stages by the concrete core cutter, that is, the concrete core cutter is not connected with a plurality of other axial members. Cutting a part of the wall (first-stage cutting) and cutting the remaining part of the wall (second-stage cutting) with a concrete core cutter to which a plurality of other axial members are added. Can do. The propulsion distance of the concrete core cutter in the first stage cutting performed on a part of the wall may be relatively small. Further, the propulsion distance of the concrete cutter required for the second stage cutting performed on the remaining part of the wall can be approximately the same as the propulsion distance required for the first stage cutting. From this, it is possible to install a concrete core cutter that is required for forming a hole that extends in a direction other than the radial direction, which is the radial direction, in a cylindrical wall such as a manhole wall. .

  Moreover, in the concrete core cutter which concerns on this invention, it can isolate | separate and decompose | disassemble into the cyclic | annular member which comprises the cutter blade, several axial direction members, and several radial direction members. These disassembled members and a plurality of other axial members can be carried through the inlet into the concrete structure, and can be assembled and a plurality of other axial directions in the concrete structure. The members can be added. A plurality of other axial members can also be carried into the concrete structure.

  The plurality of axial members and the plurality of radial members are spaced apart from each other around the axis of the annular member, and spaced apart from each other around the axis of the annular member; can do. According to this, the axial member and the radial member can be reduced in size and weight, and thereby the axial member into the concrete structure through the entrance of the concrete structure and The carrying-in operation of the radial member, and thus the carrying-in operation of the concrete core cutter can be facilitated.

  Each piece has both ends, each end having an overhanging portion projecting in the axial direction of the annular member and a joint portion extending from the overhanging portion in the circumferential direction of the annular member, and two pieces adjacent to each other Are connected to each other at these two joint portions, and each axial member may be connected to the annular member at the protruding portion of the two ends of two adjacent pieces. According to this, since the overhanging portion has higher mechanical strength than other portions, the interconnection between the annular member and the axial member can be made stronger, and by this interconnection, The unity between two adjacent pieces of the ring member can be made stronger.

  In the method for forming a hole in the cylindrical wall of the concrete structure according to the present invention, the concrete cutter is prepared, and then the annular member deformed into a non-annular shape of the concrete cutter, and the annular member A plurality of axial members separated from each other and a plurality of radial members separated from the axial members are carried into the concrete structure through its entrance. Also, a plurality of other axial members are carried together with these members or separately through the entrance into the concrete structure. Subsequently, the carried-in annular member, a plurality of axial members, and a plurality of radial members are connected to each other and assembled into a concrete core cutter.

  Next, by rotating the concrete core cutter, the cutter is pushed into the wall while exerting the cutting action of the cutter blade on the wall of the concrete structure, and a part of the wall of the concrete structure is moved. To cut. Then, a plurality of other axial members are added to the plurality of axial members, leaving the cutter blade in the wall of the structure. That is, a plurality of axial members and a plurality of radial members are separated, and then a plurality of other axial members are disposed between the plurality of axial members and the plurality of radial members. And a plurality of radial members. Then, the remaining part of the wall of the concrete structure is cut by rotationally driving a concrete core cutter to which a plurality of other axial members are added.

It is a perspective view which shows an example of a concrete core cutter. It is a disassembled perspective view of the concrete core cutter shown in FIG. FIG. 2 is a perspective view of the cutter blade of the concrete core cutter shown in FIG. 1 in a state in which two adjacent pieces constituting the cutter blade are separated. FIG. 4 is a perspective view of the cutter blade shown in FIG. 3, in which a plurality of pieces constituting the cutter blade are deformed into an elongated chain shape continuously connected in the vertical direction. It is a perspective view which shows the state which attaches the some radial direction member which makes a part of concrete core cutter shown in FIG. 1 to a part of rotation drive device. It is a perspective view which shows the state which connects the some axial direction member which makes a part of concrete core cutter shown in FIG. 1 to a some radial direction member, respectively. It is a perspective view which shows the state which connects the cutter blade which makes a part of concrete core cutter shown in FIG. 1 to several axial direction members. It is the perspective view of the concrete core cutter shown in FIG. 1 which completed the attachment to a part of rotation drive means. It is a schematic cross-sectional view of a manhole in a state where a rotation driving device for a concrete core cutter is installed in the manhole in order to form a hole in the manhole wall. It is a schematic cross-sectional view of a manhole in a state where a plurality of radial members of a concrete core cutter are attached to a rotary drive device in the manhole. It is a schematic cross-sectional view of a manhole in a state where a plurality of axial members are connected to a plurality of radial members in the manhole, respectively. It is a schematic cross-sectional view of a manhole in a state where cutter blades are connected to a plurality of axial members in the manhole. It is a schematic cross-sectional view of a manhole in the state where a part of the wall of the manhole was cut by the concrete core cutter. It is a schematic cross-sectional view of a manhole in a state where a plurality of radial members are separated from a plurality of axial members while leaving a cutter blade in the wall. It is a schematic cross-sectional view of a manhole in a state where a plurality of other axial members are joined to a plurality of axial members. FIG. 5 is a schematic cross-sectional view of a manhole with the remaining portion of the manhole wall being cut by a concrete core cutter including a plurality of other axial members that have been spliced. FIG. 4 is a schematic cross-sectional view of a manhole in a state where a concrete core cutter including a plurality of other axial members has been moved rearward in the propulsion direction after completing the remaining portion of the wall. FIG. 5 is a schematic longitudinal cross-sectional view of a manhole in a state where a concrete core cutter including a plurality of other axial members has been moved rearward in the propulsion direction after completing the remaining portion of the wall.

  Referring to FIGS. 1 and 2, a concrete core cutter according to an embodiment of the present invention is indicated generally by the numeral 10.

  The concrete core cutter 10 is provided in the concrete structure 100 in order to form a hole 105 (FIG. 14) in a wall 104 (see FIG. 9) of the concrete structure 100 having an entrance 102 (FIG. 4). The wall 104 is used for cutting. A concrete structure 100 shown in FIG. 9 includes a manhole as an example, and the wall 104 has a cylindrical shape.

  The hole 105 is formed in accordance with the hole forming method described later with reference to FIGS. 9 to 18, the manhole (hereinafter, this is denoted by reference numeral 100 if necessary) and the sewer pipe 106 (FIG. 9) This is performed in association with the flexing process of the connecting portion. The hole 105 is formed in an annular shape around the sewer pipe 106. As shown in FIG. 9, the axis 11 of the sewer pipe 106 is deviated from the straight line 12 extending on the diameter of the cylindrical wall 104 toward the inner wall surface of the wall 104, and the axis 11 of the sewer pipe 106 is a straight line. It extends parallel to the straight line l2 in a direction different from the radial direction that is the extension direction of l2, that is, in a direction other than the radial direction. The length of the extension of the axis l1 in the manhole 100 is smaller than the length (diameter) of the straight line l2 in the manhole 100, and the degree of the smallness is the deviation of the distance between the axis l1 and the straight line l2. Depends on the degree. The concrete core cutter 10 is disposed on the extension of the sewer pipe 106, more precisely on the extension of the axis 11 of the sewer pipe 106 when forming the hole 105, and is rotated around the axis 11 of the sewer pipe 106 by the rotary drive device 108 described later. Driven by rotation.

  The concrete core cutter 10 includes a cutter blade 12 that is a component having a function of exerting a cutting action on the wall 104 of the concrete structure 100. The cutter blade 12 includes a plurality of bits 14 and an annular member 16 that supports these bits 14.

  The concrete core cutter 10 is further connected to the annular member 16 in a separable manner, and includes a plurality of axial members 18 extending in the axial direction of the annular member 16, that is, in the extending direction of the axis L (FIG. 2) of the annular member 16. Each of the directional members 18 is detachably connected to the directional member 18 and extends radially inward of the annular member 16, that is, extends in the plane orthogonal to the axis L toward the axis L. Both the axial direction member 18 and the radial direction member 20 form parts that support the cutter blade 12 and have a function of transmitting the rotational driving force of the rotational driving device 108 to the cutter blade 12.

  In addition to the cutter blade 12, the plurality of axial members 18 and the plurality of radial members 20, the concrete core cutter 10 further includes a plurality of other axial members 18 ′ that can be added to the plurality of axial members 18, respectively. (FIG. 15). The other axial member 18 ′ shown has the same shape as the axial member 18 and thus the same length. The other axial member 18 'may have a length dimension that is less than or greater than the length dimension of the axial member 18 as desired.

  The annular member 16 includes a plurality (four in the illustrated example) of arc-shaped pieces 22. The four pieces 22 are connected to each other via four pin bolt and nut assemblies 24 extending in parallel with the axis L of the annular member 16. As a result, the four pieces 22 can swing around an axis parallel to the axis L of the annular member 16 and can be separated from each other. The pin bolt / nut assembly 24 includes a pin bolt 24a and a nut 24b screwed to the pin bolt 24a (FIG. 3). The plurality of bits 14 are arranged and fixed at intervals in the circumferential direction on one of two circumferential side surfaces that are continuous with both the inner and outer circumferential surfaces of the annular member 16 and are opposed to each other. The quantity of bits 14 can be set arbitrarily. The bit 14 is made of, for example, a diamond tip.

  As shown in FIG. 3, each piece 22 includes both end portions 22a in the circumferential direction and an intermediate portion 22b between both end portions 22a. Each end 22a has a projecting portion 26 projecting from the other one of the circumferential side surfaces of the annular member 16 in the axial direction of the annular member 16, and a plate-shaped joint portion 28 extending from the projecting portion in the circumferential direction of the piece 22. And have. The overhanging portion 26 has a greater length or thickness dimension with respect to the axial direction than the intermediate portion 22b of the piece 22, and thus has a relatively high mechanical strength. On the other hand, the joint portion 28 has a smaller thickness dimension than the intermediate portion 22b. The two pieces 22 adjacent to each other are overlapped with each other at the joint portions 28 at the two ends, and the pin bolts 24a of the pin bolt nut assembly 24 pass through the overlapped joint portions 28.

  The cutter blade 12 removes one pin bolt and nut assembly 24 from two pieces 22 adjacent to each other, thereby changing the four pieces 22 from an annular form ((FIGS. 1 and 2) to one of non-annular forms. 4 can be deformed into a long and slender chain shape continuously connected in the vertical direction (FIG. 4), and the cutter blade 12 has a manhole through the inlet 102 of the relatively small manhole 100. The cutter blade 12 can also be easily carried into the interior of 100. The cutter blade 12 can also be moved from one annular configuration to another in a non-annular configuration by sliding the four pieces 22 around four pin bolt nut assemblies 24, respectively. It can be transformed into a foldable form (not shown), and this form of cutter blade 12 also passes through its inlet 102 into the manhole 100 It can be carried into the easy.

  Although the number of the axial members 18 and the number of the radial members 20 can be arbitrarily set, it is desirable that the number of pieces 22 constituting the cutter blade 12 is the same, that is, four. Accordingly, the number of the other axial members 18 ′ is the same (four) as the number of the axial members 18. The four axial members 18 and the four radial members 20 can each be in contact with each other around the axis L. However, the four axial members 18 shall be arranged around the axis L at a distance from each other, and the four radial members 20 shall be arranged with a gap around the axis L. Is desirable. In the example shown in the drawing, the four axial members 18 are arranged at intervals in the circumferential direction on a surface (cylindrical surface) obtained by extending the outer peripheral surface of the annular member 16 in the axial direction. These four axial members 18 define a cylindrical space through which a guide rod 110 (see FIG. 9) described later is passed. The four radial members 20 are arranged on the plane orthogonal to the axis L with a fan-shaped gap around the axis L. According to this, the size reduction of these can be achieved on the form of the axial direction member 18 and the radial direction member 20. FIG.

  As shown in FIG. 2, each axial member 18 has a plate-like main body 18a and two elongated joint plates 18b and 18c fixed to both ends in the longitudinal direction of the main body, that is, the axial direction, and facing each other. Can be. The main body 18 a is formed of a curved plate that is curved with substantially the same curvature as the outer peripheral surface of the annular member 16. Each joint plate 18b, 18c is formed of a narrow flat plate that is curved and extends in the circumferential direction of the main body 18a with substantially the same curvature as the main body. Both end portions thereof protrude from the end of the main body 18a in the circumferential direction. Yes. Each joint plate 18b, 18c also has a width dimension that is the same as the thickness dimension of the overhanging portion 26 of the piece 22 of the cutter blade 12.

  Each axial member 18 is in contact with two projecting portions 26 of two pieces 22 adjacent to each other constituting the annular member 16 in one joint plate 18b. Further, two bolts 32 extending through the two holes 30 provided in the joint plate 18 b are respectively screwed into two screw holes (not shown) provided in the two overhang portions 26. Thereby, each axial direction member 18 is connected to the annular member 16 so as to be separable. Each separated axial member 18 and each other axial member 18 ′ can also be easily carried into the manhole 100 through the inlet 102 of the manhole 100, similar to the cutter blade 12.

  On the other hand, each radial direction member 20 consists of a flat plate, and has the outer side surface 20a and the inner side surface 20b which face the outer side and inner side of the radial direction of the annular member 16 which comprises the cutter blade 12, respectively. The outer surface 20a of each radial member 20 is curved with substantially the same curvature as the joint plate 18b of the axial member 18, and the inner surface 20b is curved with a curvature smaller than the curvature.

  Each radial member 20 is in contact with the other joint plate 18 c of each axial member 18. Further, two bolts 33 extending through the other two holes 31 provided in the joint plate 18c are respectively screwed into the two screw holes 34 provided in the radial members 20 adjacent to the outer surface 20a. Yes. Thereby, each radial direction member 20 is connected to each axial direction member 18 so that separation is possible. The four outer surfaces 20a of the four radial members 20 are on a surface (cylindrical surface) obtained by extending the outer peripheral surface of the annular member 16 in the axial direction, and the four inner surfaces 20b are guide rods 110 (see FIG. 9). A circular space through which the Each separated radial member 20 is also easily carried into the manhole 100 through the inlet 102 of the manhole 100, similar to the annular member 16, each axial member 18, and each other axial member 18 '. be able to. Further, the plurality of other axial members 18 ′ can be carried into the manhole 100 together with or separately from the annular member 16, the plurality of axial members 18, and the plurality of radial members 20.

  The formation of the hole 105 in the cylindrical wall 104 is achieved by the wall 104 by the concrete core cutter 10 without a plurality of other axial members 18 'being added, and thus having a relatively short axial length, as described below. A concrete core cutter having a relatively long axial length including a plurality of other axial members 18 'spliced after the first stage of cutting (first stage cutting) For convenience, this is denoted by reference numeral 10 ′ (FIG. 15).) The remaining part of the wall 104 is cut (second stage cutting). Here, the length in the axial direction of the concrete core cutter 10 and the length of the axial member 18 occupying most of the length in the axial direction are the length of the extension of the axis 11 in the manhole 100 and the formation of the hole 105. The concrete core cutter 10 is set to a size that allows the concrete core cutter 10 to be installed in the manhole 100 and the hole 105 to be formed. In the illustrated example, the length of the axial member 18 is slightly greater than the propulsion distance of the concrete core cutter 10 required for cutting the portion of the wall 104. Also, the length of the other axial member 18 ′ is slightly larger than the propulsion distance of the concrete core cutter 10 ′ required for cutting the remaining portion of the wall 104.

  The annular member 16, the four axial members 18 and the four radial members 20 constituting the cutter blade 12 carried into the manhole 100 can be connected to each other in the manhole 100 and assembled into the concrete core cutter 10. Thereby, the concrete core cutter 10 can be installed in the manhole 100.

  Assembling the concrete core cutter 10 is first performed around the extension of the axis l1 of the sewer pipe 106 to the wheel 112 (FIGS. 5 and 10) that forms part of the rotary drive device 108 previously installed in the manhole 100. Install at an angular interval of 90 degrees. As shown in FIG. 5, the wheel 112 is provided with a plurality of holes 113 and a plurality of protrusions 114 spaced from each other in the circumferential direction. On the other hand, each radial member 20 is provided with two screw holes 36 at a position close to the inner side surface 20b (see FIG. 2) and one hole 38 between the screw holes 36. Each radial member 20 is releasably fixed to the wheel 112 by a bolt 115 screwed into each screw hole 36 of each radial member 20 through each hole 113 of the wheel 112. Further, the protrusion 114 of the wheel 112 is fitted in the hole 38 of each radial member 20. Thereby, transmission of the rotational power from the wheel 112 to the radial member 20 is made more reliable.

  Next, as shown in FIG. 6, each axial member 18 is connected to each radial member 20 fixed to the wheel 112 using two bolts 33 (only one is shown) (see FIG. 6). 11).

  Finally, as shown in FIG. 7, the annular member 16 (the cutter blade 12 is connected to each axial member 18 connected to each radial member 20 by using two bolts 32 (only one is shown). ). Thereby, the installation of the concrete core cutter 10 in the manhole 100 and the attachment of the concrete core cutter to the rotation drive device 108 can be completed (FIGS. 8 and 12).

  The rotation drive device 108 to which the concrete core cutter 10 is attached includes a hydraulic motor (not shown) that is a rotation drive source. As shown in FIG. 9, the rotary drive device 108 can move along the guide rod 110 to the guide rod 110 extending along the extension of the axis 11 of the sewer pipe 106 in the upper space of the bottom plate 117 (FIG. 18) of the manhole 100. It is supported by. The guide rod 110 is fixed at one end thereof to a plate member 116 fixed to the inner wall surface of the manhole 100. Moreover, the guide rod 110 is fixed to a centering member 118 disposed inside the sewer pipe 106 at the other end, and is supported by the sewer pipe 106 via the centering member. The guide rod 110 includes a circular opening 120 (FIG. 5) provided at the center of the wheel 112 of the rotary drive device 108, the circular space defined by the four radial members 20, and the four axial members 18. Extends along the axis L of the annular member 16, that is, the axis of the concrete core cutter 10, through the cylindrical space defined by the above and the circular opening of the annular member 16.

  The rotary drive device 108 is also connected to a propulsion device (not shown) such as a hydraulic jack housed in an elongated box 122 disposed in the upper space and extending horizontally in the manhole 100. More specifically, it is connected to the propulsion device via a connecting member 124 (FIG. 18) provided on the bottom surface of the box 122 and extending through a slit (not shown) extending in the longitudinal direction. The box 122 is fixed to the inner wall surface of the manhole 100 and the plate member 116 at both ends thereof. The rotary drive device 108 can propel the guide rod 110 toward the sewer pipe 106 and move it in the opposite direction by operating the propulsion device.

  After the concrete core cutter 10 is installed in the manhole 100, that is, after the concrete core cutter 10 is attached to the rotation drive device 108, the rotation drive device 108 is operated and the axis L positioned on the extension of the axis l1 of the sewer pipe 106. The concrete core cutter 10 is driven to rotate around the same, and the propulsion device in the box 122 is further operated to press the rotating cutter blade 12 against the wall 104 of the manhole 100 and substantially corresponds to the length of the axial member 18. Proceed as much as you can. Thereby, a part of the wall 104 is cut (FIG. 13), and a part 105a of the annular hole 105 (FIG. 16) is formed around the sewer pipe 106 (first stage cutting). Since the concrete core cutter 10 is used for forming a part 105a of the hole 105 when viewed in the cross section of the manhole 100 shown in FIG. It is sufficient to have a small axial length.

  After the formation of the part 105 a of the hole 105, the operations of the rotary drive device 108 and the propulsion device are stopped, and the plurality of radial members 20 are separated from the plurality of axial members 18. After the separation, by operating the propulsion device, the plurality of radial members 20 are moved (retracted) together with the rotary drive device 108 to the original position before propulsion (the left direction in the figure). (FIG. 14). Thereby, it is possible to secure a space for arranging a plurality of other axial members 18 ′ added to the plurality of axial members 18 between the plurality of axial members 18 and the plurality of radial members 20. it can.

  Thereafter, a plurality of other axial members 18 ′ are arranged between the plurality of axial members 18 and the plurality of radial members 20 in the extending direction of the axis L, and a plurality of other axial members 18 ′. Are connected to the plurality of axial members 18 and the plurality of radial members 20 at both ends thereof (FIG. 15). As a result, a plurality of other axial members 18 ′ are added to the plurality of axial members 18, respectively. The interconnection between the axial member 18 and the other axial member 18 ′ and the interconnection between the other axial member 18 ′ and the radial member 20 are respectively made between the axial member 18 and the radial member 20. As with the interconnection, this can be done using bolts (not shown).

  Next, a concrete core cutter provided with a plurality of other axial members 18 'joined is rotated around the axis L and further propelled. Accordingly, the concrete core cutter 10 ′ is rotated and propelled until the annular member 16 (the cutter blade 12) penetrates the wall 104 of the concrete structure 100 (second stage cutting). As a result, the remaining part 105b of the wall 104 is cut, and a hole 105 is formed in the wall 104 (FIG. 16). After the formation of the hole 105, the propulsion device is operated, and the concrete core cutter 10 ′ is retracted in the direction opposite to the propulsion direction (left direction in the drawing) together with the rotational drive device 108 in the inoperative state (FIG. 17). ).

  Then, in order to perform the said flexible process, the cyclic | annular hole 105 is filled with the water stop material (not shown) which can be elastically deformed like silicone.

  Instead of the example shown in FIG. 1, the concrete core cutter 10 includes, for example, a cutter blade 12 constituted by an annular member 16 composed of two pieces 22, two axial members 18, and two radial members 20. Provided (not shown), equipped with a cutter blade 12 composed of an annular member 16 composed of three pieces 22, three axial members 18, and three radial members 20 (not shown), A cutter blade 12 composed of an annular member 16 composed of six pieces 22, six axial members 18, and six radial members 20 (not shown) can be used.

10, 10 'Concrete core cutter 12 Cutter blade 14 Bit 16 Annular member 18 Axial member 18' Other axial member 20 Radial member 22 Piece 100 Manhole (concrete structure)
102 Manhole entrance 104 Manhole wall 106 Sewer pipe 108 Rotation drive

Claims (4)

A cutter blade comprising an annular member for supporting a plurality of bits, the annular member being capable of swinging relative to each other about an axis parallel to the axis of the annular member so that it can be deformed non-annularly And a cutter blade comprising a plurality of arc-shaped pieces detachably connected to each other,
A plurality of axial members that are separably connected to the annular member and extend in the axial direction of the annular member;
A concrete core cutter comprising a plurality of radial members connected to a plurality of axial members in a separable manner and extending radially inward of the annular member;
A concrete core cutter comprising a plurality of other axial members that can be added to the plurality of axial members.   The concrete core cutter according to claim 1, wherein the plurality of axial members are arranged at intervals around the axis of the annular member, and are arranged with a gap around the axes of the plurality of annular members. Each piece includes both end portions, each end portion having an overhanging portion projecting in the axial direction of the annular member, and a joint portion extending from the overhanging portion in the circumferential direction of the annular member,
Two pieces adjacent to each other are connected to each other at these two joint portions, and each axial member is connected to the annular member at a protruding portion of two ends of the two pieces adjacent to each other. The concrete core cutter according to claim 1 or 2. A method of forming a hole extending in a direction other than a radial direction in a cylindrical wall of a concrete structure having an entrance provided in the ground,
Preparing the concrete core cutter according to any one of claims 1 to 3,
The annular member deformed non-annularly, a plurality of axial members separated from the annular member, and a plurality of radial members separated from the axial member are carried into the concrete structure through its inlet. To do,
Carrying other axial members together with or separately from the annular member, the plurality of axial members and the plurality of radial members into the concrete structure through its inlet;
The annular member, the plurality of axial members and the plurality of radial members that are carried in are connected to each other, thereby assembling a concrete core cutter,
Rotating the assembled concrete core cutter to drive the cutter blade into the wall of the concrete structure to cut a part of the wall of the concrete structure;
Adding a plurality of other axial members to each of the plurality of axial members, leaving the cutter blade in the wall of the structure;
A method for forming a hole, comprising cutting a remaining part of a wall of the concrete structure by rotationally driving a concrete core cutter including a plurality of other axial members.

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