Perforator and perforation method

Abstract

To provide a drill and a drilling method that allow drilling in pipes even when sufficient support reaction force of a pipe such as an indoor pipe cannot be obtained, and thereby smoothly perform branch construction in pipes such as indoor pipes whose sufficient support reaction force cannot be obtained.SOLUTION: Since a load in a reverse direction of a drilling direction is not applied until an edge of a hole saw 40 abuts on a pipe P and drilling is started, a spindle 30 and the hole saw 40 are fed along a screw pitch of a part 21 to be screwed. Then, when the edge of the hole saw 40 abuts on the pipe P and a load of a specified value or more is applied in the reverse direction of the drilling direction, the spindle 30 rotates idly together with a feed nut 20 and cannot be fed at the screw pitch, and therefore torque transmission to the hole saw 40 is blocked.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a drilling machine for drilling pipes and a drilling method using this drilling machine.

Background Art

[0002] Conventionally, a drilling machine attached to a flange of a branch plug attached to a pipe has been disclosed (for example, Patent Document 1). Such a drilling machine is provided with a rotating shaft member having a cutter unit attached to a body through hole, and a shaft center hole penetrating from the lower end to the central portion of the rotating shaft member is provided. Then, a first shaft slit communicating from the side surface of the rotating shaft member to the shaft center hole and a first body slit communicating from the side surface of the body to the body through hole are provided. Thereby, chips can be easily pushed out and taken out from the cutter unit.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Conventional drilling machines including the drilling machine disclosed in Patent Document 1 are generally used for branch work of pipes supported on the ground or underground. Here, when drilling the upper surface of a pipe using a conventional drilling machine, since the pipe to be drilled is supported on the ground or underground, the reaction force of the force pressing the hole saw against the upper surface of the pipe is secured by the support of the pipe.

[0005] However, when it is not possible to sufficiently obtain the support reaction force of the pipe, such as a pipe suspended indoors, it has been difficult to drill the pipe. For this reason, there has been a problem that branch work cannot be smoothly performed on indoor pipes where the support reaction force cannot be sufficiently obtained.

[0006] In view of such problems, the present invention provides a drilling machine capable of drilling a pipe even when sufficient support reaction force of the pipe cannot be obtained, and a drilling method, thereby smoothly performing branch work on pipes such as indoor pipes where sufficient support reaction force cannot be obtained.

Means for Solving the Problems

[0007] In order to solve such problems, the drilling machine according to the present invention is a drilling machine for making a hole in a pipe, which includes a spindle having a threaded portion formed on an outer peripheral surface, a feed nut having a threaded portion formed thereon to be screwed with the threaded portion, a drilling portion attached to the spindle, and an overload prevention function for blocking torque transmission when a load in a direction opposite to the drilling direction is applied to the spindle. A bearing provided on the outer periphery of the feed nut to assist the rotation of the feed nut, and the feed nut includes a mounting portion to which the bearing is attached and a protruding portion protruding in the outer peripheral direction, and the overload prevention function is provided between the mounting portion of the feed nut and the protruding portion It is characterized by the above.

[0008] Further, the drilling machine according to the present invention further includes a bearing provided on an outer periphery of the feed nut for assisting rotation of the feed nut. The feed nut includes a mounting portion to which the bearing is attached and a protruding portion protruding in an outer peripheral direction. The overload prevention function is provided between the mounting portion and the protruding portion of the feed nut.

[0009] Further, the drilling method according to the present invention is a drilling method for making a hole in a pipe using a drilling machine. The drilling machine includes a spindle having a threaded portion formed on an outer peripheral surface, a feed nut having a threaded portion formed thereon to be screwed with the threaded portion, a drilling portion attached to the spindle, and an overload prevention function for blocking torque transmission when a load in a direction opposite to the drilling direction is applied to the spindle. A bearing provided on the outer periphery of the feed nut to assist the rotation of the feed nut, and the feed nut includes a mounting portion to which the bearing is attached and a protruding portion protruding in the outer peripheral direction, and the overload prevention function is provided between the mounting portion of the feed nut and the protruding portion It is characterized by the above.

Effects of the Invention

[0010] According to the present invention, even when it is not possible to sufficiently obtain the support reaction force of a pipe, a drilling machine capable of drilling the pipe and a drilling method can be provided, whereby branch work can be smoothly performed even on indoor pipes where the support reaction force cannot be sufficiently obtained.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Mode for Carrying Out the Invention

[0012] Hereinafter, the first embodiment of the present invention will be specifically described with reference to the drawings.

[0013] (External view of the drilling machine 1) First, with reference to FIG. 1, the external view of the drilling machine 1 will be described.

[0014] The drilling machine 1 includes a cylindrical body 10 having a length in the vertical direction, a feed nut 20 attached to the opening 11 of the body 10, and a spindle 30 attached to the feed nut 20. Further, a drill 40 having a blade is attached to the spindle 30.

[0015] (X-X cross-sectional view of the drilling machine 1 under no load) Next, with reference to FIG. 2, the X-X cross-sectional view of the drilling machine 1 under no load will be described.

[0016] As shown in FIG. 2, a bearing 50 for assisting the rotation of the feed nut 20 is provided on the outer periphery of the feed nut 20. Specifically, a mounting portion 22 is provided on the outer periphery of the feed nut 20, and the bearing 50 is attached to the outer periphery of the mounting portion 22.

[0017] Further, below the bearing 50 and on the outer periphery of the feed nut 20, a disc spring 60 for adjusting the feed amount of the spindle 30 is provided. Specifically, inside the body 10 and at the bottom of the feed nut 20, a protruding portion 23 protruding outward in the circumferential direction of the feed nut 20 is provided, and the disc spring 60 is provided between the mounting portion 22 and the protruding portion 23.

[0018] In this embodiment, a plurality of disc springs 60 are provided. Here, the number and combination of the disc springs 60 vary depending on the reaction force against the horsehead 40. In this embodiment, three disc springs 60 in a single series arranged in parallel so as to bend downward and three disc springs 60 in a single series arranged in parallel so as to bend upward are set as one set, and three sets of disc springs 60 are provided. Note that the larger the deflection amount of the disc spring 60, the easier it is to adjust the specified torque when the disc spring 60 operates.

[0019] A threaded portion 31 is provided on the outer periphery of the spindle 30, and a threaded portion 21 to be threaded with the threaded portion 31 is provided on the inner periphery of the feed nut 20. Here, in this embodiment, the threaded portion 31 is constituted by a male screw, and the threaded portion 21 is constituted by a female screw.

[0020] Note that a stopper 24 that abuts against the body 10 is provided on the feed nut 20.

[0021] A vibration damping portion 32 for suppressing the vibration of the spindle 30 is provided on the spindle 30. Here, the vibration damping portion 32 is provided inside the body 10 and protrudes outward in the circumferential direction of the spindle 30. Further, the vibration damping portion 32 can prevent the core deviation of the spindle 30 by abutting against the inner wall 12 of the body 10.

[0022] Here, when drilling the pipe P described later using the drilling machine 1, until the holder 40 abuts against the pipe P described later and drilling starts, no torque is applied to the holder 40. That is, no load is applied to the drilling machine 1 in the direction opposite to the feed direction of the spindle 30, that is, the drilling direction (the direction of arrow A). For this reason, when the spindle 30 rotates in the rotational direction (the direction of arrow B), the spindle 30 and the holder 40 are fed in the drilling direction (the direction of arrow A) along the screw pitch of the screwed portion 21 of the feed nut 20.

[0023] (Cross-sectional view of the drilling machine 1 in the X-X direction during loading) Next, with reference to FIG. 3, the X-X cross-sectional view of the drilling machine 1 during loading will be described.

[0024] When drilling the pipe P described later using the drilling machine 1, when the blade of the holder 40 abuts against the pipe P described later and drilling starts, a load is generated in the direction opposite to the drilling direction (the direction of arrow C). When this load exceeds a specified value, a force is transmitted from the spindle 30 and the feed nut 20 is pushed up. The "specified value" refers to a predetermined value such that the blade of the holder 40 does not bite into the pipe P.

[0025] When the feed nut 20 is pushed up, a load is applied to the disc spring 60 provided between the mounting portion 22 and the protruding portion 23, and the disc spring 60 is compressed. When the disc spring 60 is compressed, friction occurs between the bearing 50 and the disc spring 60, so that the feed nut 20 and the bearing 50 rotate around the spindle 30, and thus torque transmission to the holder 40 is blocked. Thereby, an overload on the holder 40 can be prevented, breakage of the blade of the holder 40 can be prevented, and a reaction force acting on the operator's hand can be prevented.

[0026] At this time, since the spindle 30 is idling, it is not fed along the screw pitch in the drilling direction, and since the holder 40 is not receiving torque transmission from the spindle 30, it is not fed along the screw in the drilling direction.

[0027] Then, when the amount of compression on the disc spring 60 decreases and the friction decreases, the feed nut 20 and the bearing 50 stop rotating with the spindle 30. As a result, the spindle 30 and the drill chuck 40 are again fed in the drilling direction along the screw pitch of the threaded portion 21.

[0028] Then, when the compression reaction force of the disc spring 60 disappears, the spindle 30 and the drill chuck 40 are again fed at the screw pitch of the threaded portion 21, and when a load is applied to the disc spring 60, they are fed in the drilling direction by the compression reaction force of the disc spring 60. By repeating these operations, the drilling of the pipe P is completed.

[0029] (Mode of use of the drilling machine 1 when drilling from the upper surface of the pipe P) Next, with reference to FIG. 4, the mode of use of the drilling machine 1 when drilling from the upper surface of the pipe P will be described.

[0030] When drilling the pipe P from the upper surface using the drilling machine 1 in the present embodiment, the drilling machine 1 is attached to the flange F of the shutter device attached to the branch joint S. Then, an electric motor D (for example, a motor, an electric drill) described later is attached to the upper part of the spindle 30 of the drilling machine 1 for drilling. Note that the drilling machine 1 may be directly attached to the branch joint S.

[0031] Then, when the blade of the drill chuck 40 abuts against the pipe P and drilling starts, a load in the direction opposite to the drilling direction (the direction of arrow C) is applied. When this load exceeds a specified value, the torque transmission between the spindle 30 and the drill chuck 40 is interrupted, and the feed by the screw in the drilling direction stops. When the load decreases, the torque transmission is resumed, and it is fed along the screw in the drilling direction. By repeating these operations, the pipe P rotates while appropriately releasing the reaction force so as not to swing, and the pipe P is cut little by little.

[0032] That is, until the drill 40 abuts against the pipe P and drilling starts, the spindle 30 is fed at the screw pitch of the threaded portion 21. As the load on the blade of the drill 40 increases and when the load exceeds a specified value, torque transmission between the spindle 30 and the drill 40 is interrupted, and feeding by the screw in the drilling direction no longer occurs.

[0033] (Mode of use of the drilling machine 1 when drilling the side surface or bottom surface of the pipe P) Next, with reference to FIG. 5, the mode of use of the drilling machine 1 when drilling the side surface or bottom surface of the pipe P will be described.

[0034] When drilling the side surface or bottom surface of the pipe P using the conventional drilling machine 1, for example, as shown in FIG. 5(B), when drilling the bottom surface of the pipe P suspended from the ceiling in the room, sufficient support reaction force of the pipe P cannot be obtained, and drilling the pipe cannot be performed.

[0035] Also, when drilling the side surface or lower surface of the pipe P using the conventional drilling machine 1, the operator may have to work in a difficult position depending on the location where the pipe is installed. For example, as shown in FIG. 5(A), when drilling the side surface of the pipe P installed indoors, the operator has to kneel and press the drilling machine 1 against the pipe P. Also, as shown in FIG. 5(B), when drilling the bottom surface of the pipe P suspended from the ceiling in the room, the operator has to look upward and raise the arm to press the drilling machine 1 against the pipe P.

[0036] And when drilling the side surface or lower surface of the pipe P installed indoors, sufficient support reaction force of the pipe P cannot be obtained, and it has been difficult to drill the pipe P. Here, it is conceivable to make the screw pitch of the threaded portion 21 finer. However, if the screw pitch of the threaded portion 21 is made finer, the time until the blade of the drill 40 abuts against the pipe line P and drilling starts becomes long, resulting in a problem that the working time becomes long.

[0037] On the other hand, when piercing the side surface of the pipe P or the bottom surface of the pipe P using the drilling machine 1 in this embodiment, until the blade of the drill 40 contacts the pipe path P and drilling starts, no load in the direction opposite to the drilling direction is applied. Therefore, the spindle 30 and the drill 40 are fed along the screw pitch of the threaded portion 21. Then, when the blade of the drill 40 contacts the pipe path P and drilling starts, a load in the direction opposite to the drilling direction (the direction of arrow C) is applied. When this load exceeds a specified value, the torque transmission from the spindle 30 to the drill 40 is interrupted, and the feed nut 20 and the bearing 50 rotate together with the spindle 30, and screw feed in the drilling direction does not occur.

[0038] Also, when piercing a pipe P suspended from the ceiling, it is necessary to press the drilling machine 1 from below the pipe P for piercing. However, an excessive load may be applied to the pipe P, and there is a risk that the suspended pipe P may come off or the pipe P may be damaged. Also, when piercing from the side or below the pipe P, the operator may have to adopt an unreasonable posture depending on the position where the pipe P is installed. And when a reaction force acts on the operator's hand while the operator is piercing the pipe P in an unreasonable posture, there are problems with safety.

[0039] On the other hand, when a load equal to or greater than a specified value is applied in the direction opposite to the drilling direction, the drilling machine 1 in this embodiment causes the feed nut 20 and the bearing 50 to rotate together with the spindle 30, so that the spindle 30 idles and is not fed at the screw pitch of the threaded portion 21, thereby interrupting the torque transmission to the drill 40. As a result, the reaction force on the operator is appropriately relieved for the drill 40, and the drilling operation can be performed safely.

[0040] Here, it is also conceivable to mount a gear on the drilling machine 1 and adjust the feed amount of the spindle 30 and the transmission of torque by this gear. However, if a gear is mounted on the drilling machine 1, the weight of the drilling machine 1 will increase, resulting in a problem that it will become a burden on the operator. In particular, when performing the drilling operation of the pipe P in a narrow room, if the weight of the drilling machine 1 is heavy, the burden on the operator is immeasurable. On the other hand, since the drilling machine 1 in the present embodiment does not need to mount a gear, the weight of the drilling machine 1 can be made lighter compared to the case where a gear is mounted, so that the burden on the operator can be reduced.

[0041] (Second Embodiment of the Drilling Machine 1) Next, with reference to FIG. 6, a second embodiment of the drilling machine 1 will be described.

[0042] In the above-described first embodiment, the transmission of torque is blocked by the disc spring 60, but in the second embodiment, the transmission of torque is blocked by the coil spring 73.

[0043] Specifically, as shown in FIG. 6(A), when the iron ball 72 is fitted into the ball groove 71 provided below the thrust bearing 70 in the drilling machine 1 in the second embodiment, the torque of the spindle 30 is transmitted to the holder 40. At this time, the spindle 30 is fed in the drilling direction along the screw pitch of the screwed portion 21.

[0044] As shown in FIG. 6(B), when a reaction force greater than a specific value occurs with respect to the holder 40, the friction generated between the ball groove 71 and the iron ball 72 increases, and the iron ball 72 fitted in the ball groove 71 comes off. Then, the iron ball 72 moves in the drilling direction A and presses the coil spring 73. As a result, the transmission of torque to the holder 40 is blocked, and the spindle 30 rotates idly.

[0045] When the compression reaction force of the coil spring 73 disappears, the iron ball 72 fits into the ball groove 71 again, and the spindle 30 and the drill 40 are fed at the screw pitch of the screwed portion 21. By repeating these operations, the drilling of the pipe P is completed.

[0046] As described above, according to the drilling machine 1 of the present invention, until the blade of the drill 40 contacts the pipe P and drilling starts, no load in the direction opposite to the drilling direction is applied, so the spindle 30 and the drill 40 are fed along the screw pitch of the screwed portion 21. Then, when the blade of the drill 40 contacts the pipe P and a load equal to or greater than a specified value is applied in the direction opposite to the drilling direction, the spindle 30 idles by rotating with the feed nut 20 and is no longer fed at the screw pitch, so the torque transmission to the drill 40 is interrupted. Thereby, even when the support reaction force of the pipe P cannot be sufficiently obtained, such as in the case of a pipe P suspended indoors, the pipe P can be drilled, and thus the branch work can be smoothly performed even on indoor pipes where the support reaction force cannot be sufficiently obtained. In addition, since it is not necessary to make the screw pitch of the spindle 30 fine, the working time until the blade of the drill 40 contacts the pipe line P can be shortened.

[0047] (First Invention) The first invention is a drilling machine for making a hole in a pipe (for example, pipe P), comprising a spindle (for example, spindle 30) having a threaded portion (for example, threaded portion 31) formed on its outer peripheral surface, a feed nut (for example, feed nut 20) having a threaded portion (for example, threaded portion 21) screwed with the threaded portion, a drilling portion (for example, drill 40) attached to the spindle, and an overload prevention function (for example, disc spring 60, coil spring 73) for interrupting torque transmission when a load in the direction opposite to the drilling direction is applied to the spindle.

[0048] (Second Invention) The second invention further includes a bearing (for example, bearing 50) provided on the outer periphery of the feed nut to assist the rotation of the feed nut. The feed nut includes a mounting portion (for example, mounting portion 22) to which the bearing is attached, and a protruding portion (for example, protruding portion 23) protruding in the outer peripheral direction. The overload prevention function is provided between the mounting portion and the protruding portion of the feed nut, and it is a drilling machine according to the first invention.

[0049] (Third Invention) The third invention is a drilling method for making holes in a pipe using a drilling machine. The drilling machine includes a spindle (for example, spindle 30) having a threaded portion (for example, threaded portion 31) formed on its outer peripheral surface, a feed nut (for example, feed nut 20) having a threaded portion (for example, threaded portion 21) screwed with the threaded portion, a drilling portion (for example, holsaw 40) attached to the spindle, and a clutch mechanism (for example, disc spring 60, coil spring 73) that cuts off the transmission of torque when a load in the direction opposite to the drilling direction is applied to the spindle. It is a drilling method characterized by this.

[0050] Note that the matters shown in the above embodiments and modifications are merely examples, and can be appropriately changed without departing from the scope of the present invention.

Explanation of Reference Numerals

[0051] 1 Drilling machine 10 Body 11 Opening 12 Inner wall 20 Feed nut 21 Threaded portion to be screwed 22 Mounting portion 23 Protruding portion 30 Spindle 31 Threaded portion 32 Anti-vibration portion 40 Holsaw 50 Bearing 60 Disc spring 70 Thrust bearing 71 Ball groove 72 Iron ball 73 Coil spring D Electric motor F Flange P Pipe S Branch joint

Claims

1. A drilling machine for making holes in pipes, comprising: a spindle having a threaded portion formed on its outer peripheral surface; a feed nut having a threaded portion to be threaded with the threaded portion; a drilling portion attached to the spindle; an overload prevention function for blocking torque transmission when a load in a direction opposite to the drilling direction is applied to the spindle; a bearing provided on the outer periphery of the feed nut to assist the rotation of the feed nut; and the feed nut has a mounting portion to which the bearing is attached, and a protruding portion protruding in the outer peripheral direction, and the overload prevention function is provided between the mounting portion and the protruding portion of the feed nut. The drilling machine is characterized by this.

2. A drilling method for making holes in pipes using the drilling machine, wherein the drilling machine has a spindle having a threaded portion formed on its outer peripheral surface, a feed nut having a threaded portion to be threaded with the threaded portion, a drilling portion attached to the spindle, an overload prevention function for blocking torque transmission when a load in a direction opposite to the drilling direction is applied to the spindle, a bearing provided on the outer periphery of the feed nut to assist the rotation of the feed nut, and the feed nut has a mounting portion to which the bearing is attached, and a protruding portion protruding in the outer peripheral direction, and the overload prevention function is provided between the mounting portion and the protruding portion of the feed nut. The drilling method is characterized by this.

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