JP3538457B2 - Pipe cutter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pipe cutter used for cutting a pipe such as a gas pipe or a water pipe buried underground from the inside of the pipe while being buried.

[0002]

2. Description of the Related Art When part of a pipe such as a gas pipe buried underground is to be removed or replaced, digging and digging the buried pipe requires a large amount of labor.
For this reason, conventionally, a pipe cutter is inserted into the inside of the pipe from the above-ground opening provided in a part of the buried pipe, and the pipe is cut from the inside so that the pipe in the required section can be pulled out and removed or replaced The law is taking place.

Conventionally, a pipe cutter used for this purpose is disclosed in, for example, Japanese Patent Application Laid-Open No. 4-3399 previously filed by the present applicant.
Japanese Patent No. 90 is disclosed. Referring to FIG. 8, the pipe cutter of the prior art will be described. P is a pipe to be cut buried underground, and an opening above the ground is provided at an appropriate position in the pipe. The cutter body 101 is inserted into a cutting position in the pipe.

A pipe cutter body 101 inserted into a pipe of a pipe to be cut has a cylindrical cylinder 10 having an outer diameter capable of being inserted into a pipe P to be cut.
2, a rotary shaft 104 coaxially inserted into the cylinder 102, a slider 105 connected and fixed to the tip of the rotary shaft 104 via a screw, and an abutting surface 105 ′ of the slider 105. A cutter holder 106 that moves toward and away from the inner surface of the pipe by the axial movement, and a circular cutter blade 107 pivotally supported on the side of the cutter holder 106 facing the inner surface of the pipe.
And The pipe cutter body 101 also includes an inner cable 117 connected and fixed to the rotating shaft 104.
And an out cable 116 rotatably connected to the cylinder 102.
Is connected to an external drive mechanism (not shown) through the above-mentioned opening of the pipe, so that the pipe cutter 101
The rotational force of the motor output shaft is transmitted to the inner cable 117, and forward and backward movements are given by handle means (not shown).

As can be seen with reference to FIG. 9, two rolling rollers 109 are provided on the outer periphery of the cylinder 102 on the cylinder 102 at a side opposite to the side on which the cutter blade 107 is supported. And these rolling rollers 109 are connected to the pipe P
Rolling in contact with the inner surface of the cylinder assists the rotation of the cylinder 102.

Further, as can be understood with reference to FIGS. 8 and 10, a key groove 113 is provided in the rotary shaft 104 inserted into the cylinder 102, and a key groove is provided in a corresponding portion of the cylinder 102. Key 1 shorter than groove 113
14 is fixed. The key groove 11 for the key 114
3 is formed to be long in the axial direction, whereby the rotary shaft 104 can slide in the axial direction with a required stroke with respect to the cylinder 102, but the rotary shaft 104 is integrated with the cylinder 102 in the rotational direction. It is configured to rotate in a dynamic manner.

[0007] Based on the above structure, the cutting operation of the pipe cutter is such that the rotational force transmitted from the motor of the external drive mechanism is transmitted from the inner cable 117 to the rotating shaft 104, and the slider 105, the cutter holder 106, The cutter holder 106 and the cutter blade 107 approach and separate toward the inner surface of the pipe by rotating the inner cable 117 during the rotation operation in the axial direction with a required stroke by the handle means while integrally rotating the cutter blade 107. be able to.

During the cutting operation, the rotating shaft 104 is configured to be movable in the axial direction with respect to the cylinder 102, so that the slider 105 moves in the retreating direction (the direction B in FIG. 8) together with the rotating shaft 104. Since the cutter 106 is guided by the inclined surface 105 ′ by the axial movement of the slider 105 and moves in the direction approaching the inner surface of the pipe P while rotating, the cutter blade 7 supported by the cutter holder 106 The cut is started by contacting the inner surface.

After the cutting is completed, the rotating shaft 104 and the slider 105 are both moved in the forward direction by the urging force of the spring 100 by returning the inner cable 117 to the forward direction (direction A in FIG. 8) by the handle means. The cutter holder 106 is separated in a direction away from the inner surface of the pipe, the cutter blade 107 is separated from the inner surface of the pipe, and the pipe cutter body 101 can be pulled back in the pipe.

[0010]

However, the above-mentioned prior art pipe cutter has the following problems. First, as can be seen with reference to FIGS. 9 and 10, the cylinder 102 is provided with a rolling roller 109 on the outer periphery of the cylinder located on the side opposite to the side on which the cutter blade 7 is supported, These rolling rollers 109 are pipes P
Rolling in contact with the inner surface of the cylinder assists the rotation of the cylinder 102. However, since the rolling roller 109 is fixed to the outer peripheral surface of the cylinder so as not to move in the radial direction of the cylinder, a problem is likely to occur in the cutting operation.

That is, at the start of pipe pipe cutting,
The cutter blade 107 starts to cut into the inner surface of the pipe, and the reaction force generated by the cut is transmitted to the two rotating rollers 109 via the cylinder 102. At this time, the two rolling rollers 109 come into contact with the inner surface of the pipe to support the cylinder 102 on the side where the cutter blade 107 is pivotally supported, thereby assisting the rotation of the cylinder 102 in the pipe. However, as the cutter blade 107 cuts into the inner surface of the pipe, the cylinder 102 is rotating, but when the cutting of the pipe is started, when the cutting is in progress, and when the cutting is likely to be completed, the cutter blade 10 is cut.
7 receive different reaction forces, the cylinder 10
The rotation centers 2 are changing, that is, the cylinder 102 is eccentrically rotating in the pipe.

Therefore, when the cutter blade 107 starts to cut into the inner surface of the pipe at the start of the cutting operation, the cutter blade 1
07 receives a large resistance, so that a pipe cutting noise is generated. In addition, when the cutting is started, when the cutting is in progress, and when the cutting is about to be completed, the resistance received by the cutter blade 107 is changing, so that the cut surface of the pipe pipe becomes uneven. Furthermore, since the cylinder 102 is eccentrically rotated in the pipe, the cutter blade 107 is subjected to severe vibration and the blade is significantly damaged. Since the cutter blade 107 receives a large resistance and the blade is likely to be damaged, it takes 5-6 minutes to cut the 250 mm and 320 mm pipes, so that the efficiency of the cutting operation is reduced.

Further, since there is no means for notifying the completion of the cutting of the pipe, it is easy to misunderstand that the cutting has been completed even when the cutting operation has not been completed, and it is not possible to remove a part to be removed or replaced. There is fear. On the other hand, even if the cutting is completed, the fact that the cutting is not known is not known, so there is a possibility that the motor for the cutting work may continue to rotate, and not only the waste of power but also the inability to immediately enter the next construction stage. In addition, the efficiency of the entire construction is further reduced.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art pipe cutter and to provide a pipe cutter which can uniformly and quickly cut an underground pipe at a desired position from the inside of the pipe. I do. It is another object of the present invention to notify an operator of the completion of cutting of a pipe.

[0015]

In order to achieve the above object, the present invention provides a cylindrical cylinder having an outer diameter which can be inserted into a pipe to be cut, and a shaft located in the cylinder. A rotating shaft that is slidable in the direction and rotates together with the cylinder in the rotating direction, a slider that is connected to the tip of the rotating shaft, and that has an inclined surface that is inclined with respect to the axial direction. A cutter holder which is abutted and slides in a direction of approaching and separating from the inner surface of the pipe by axial movement of the slider, and an inner end of a drive cable having a required length is provided at a base end of the rotating shaft. The cable is connected and fixed, and the drive cable is connected to an external drive mechanism via the above-ground opening of the piping pipe, and the rotational force of the motor output shaft is transmitted to the inner cable, In the pipe cutter configured to give forward and backward movements to the inner cable, the outer circumference of the cylinder has a plurality of rolling contacts on the circumference of the distal end and the proximal end thereof in contact with the inner surface of the pipe. Rollers are equally arranged, and the rolling rollers are movable so as to protrude in the radial direction of the cylinder when the rotating shaft is retracted, so that the cylinder always rotates concentrically in the pipe pipe. It is characterized by becoming.

Further, according to the present invention, an ammeter device is installed in a power supply circuit of a motor to which an inner cable is connected in the external drive mechanism, and the ammeter device responds to a load at the time of cutting by a cutter blade. The moving current value detection pointer, the current value setting pointer that sets the current value at the end of cutting in advance, and the current value detection pointer due to the decrease in the current value at the end of cutting of the piping pipe become the current value setting pointer. Means for issuing an alarm when it moves to a corresponding position.

[0017]

According to the above construction, even if the cutter blade cuts into the inner surface of the pipe, the rotation center of the cylinder does not change.
The cylinder always rotates concentrically from the start of cutting of the pipe to the end of cutting. Further, the resistance of the cutter blade is constant from the time when the cutter blade starts to cut into the inner surface of the pipe until the time when the cutting operation is completed.

Since the ammeter device for notifying the completion of the cutting of the pipe cutter is provided, the
Withdrawal of the pipe cutter without completing the cutting operation can be avoided. Also, when the disconnection is completed, the buzzer sounds and notifies the operator that the disconnection is completed,
The motor power used for cutting work can be turned off immediately,
Not only power saving, but also immediate entry into the next construction stage, which will increase the efficiency of the entire construction.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. In FIG. 1, P is a pipe to be cut which is buried in the ground and has a ground opening at an appropriate position in the pipe, from which a pipe cutter body 1 is inserted into a cutting position in the pipe. You. The pipe cutter body 1 includes a cylindrical cylinder 2 having an outer diameter that can be inserted into a pipe P to be cut, a rotary shaft 4 positioned inside the cylinder 2 and inserted coaxially, and a rotary shaft 4. Slider 5 which is connected and fixed to the end of the head via a screw 8
And a cutter holder 6 which is supported in contact with the inclined surface 5 ′ of the slider 5 and moves toward and away from the inner surface of the pipe by its axial movement, and is supported by the side of the cutter holder 6 facing the inner surface of the pipe. And a circular cutter blade 7.

An inner cable 17 of a drive cable 15 having a required length is connected and fixed to a base end of the rotary shaft 4, and the drive cable 15 is connected to an external drive mechanism (not shown) through a ground opening of a pipe. ), The rotational force of the motor output shaft is transmitted to the inner cable 17, and forward and backward movements are given to the inner cable 17 by handle means (not shown).

As can be seen with reference to FIGS. 1 and 2, on the outer periphery of the cylinder 2, three rolling rollers 9 which are in contact with the inner surface of the piping pipe are provided on the circumference of the distal end and the proximal end thereof. And the rolling rollers 9 are arranged on the rotating shaft 4.
Is movable so as to protrude in the radial direction of the cylinder 2 when it is pulled in the retreating direction (direction B in FIG. 1). That is, each rolling roller 9 is pivotally supported by the mover 20, and each movable element 20 that supports the rolling roller 9 is
Is mounted so as to be movable in the radial direction of the cylinder 2 (to the position of the virtual line in FIG. 2). Cylinder 2
When the mover 20 moves in the radial direction of the cylinder 2, when the mover 20 moves in the radial direction of the cylinder 2, both end surfaces 20 ′ of the mover 20 that comes into contact with the Always moves linearly. Accordingly, all the rolling rollers 9 supported by the respective movers 20 move linearly in the radial direction of the cylinder 2.

A female screw hole is formed in the slider 5, and a shaft member 18 having a male screw portion is connected to the slider 5 by a screwing action. Since the shaft member 18 has a tapered portion 18 ′ that is always in contact with the tapered portion 20 ″ of the mover 20, the taper of the shaft member 18 is moved with the movement of the slider 5 and the shaft member 18 in the retreating direction (direction B in FIG. 1). The portion 18 'presses the mover 20 movably mounted on the cylinder 2 in the radial direction of the cylinder 2. Further, a shaft member 19 having the same structure as the shaft member 18 is provided at the base end of the rotary shaft 4. That is, the shaft member 19 has a male screw portion and the same tapered portion 19 ′ as the shaft member 18.
Having. The rotating shaft 4 is connected to the inner cable 17 by the male screw portion and the female screw hole formed in the inner cable 17. Similarly to the above, the tapered portion 19 ′ of the shaft member 19 is always in contact with the tapered portion 20 ″ of the mover 20 provided on the base end side of the cylinder 2 and supporting the rolling roller 9. Cable 17 retreat direction (FIG. 1
With the movement in the direction B), the tapered portion 19 ′ presses the mover 20 movably mounted on the cylinder 2 in the radial direction of the cylinder 2.

In FIGS. 1 and 4, the rotary shaft 4 inserted into the cylinder 2 has a keyway 13.
A key 14 shorter than the key groove 13 is fixed to a portion of the cylinder 2 corresponding to this. Key 1 above
4, the keyway 13 is formed to be longer in the axial direction,
Thus, the rotary shaft 4 can slide in the axial direction with respect to the cylinder 2 with a required stroke, but the rotary shaft 4 rotates integrally with the cylinder 2 in the rotational direction.

Further, in FIG. 1, the slider 5 connected and fixed to the tip of the rotary shaft 4 has its tip side higher in the axial direction, and has the side connected to the other rotary shaft 4 (the right side in FIG. 1). The sloping surface 5 'has an inclined surface 5' which is inclined low. On both sides of the inclined surface 5 ', ridges 5 "projecting from side to side are formed as shown in FIG. Cutter holder 6 supported on surface 5 '
Has a pair of concave grooves 6 ′ so as to sandwich the left and right convex ridges 5 ″ from both sides. The engagement of the concave grooves 6 ′ with the convex ridges 5 ″ allows the cutter holder 6 to move the slider 5. The cutter holder 6 is slidably supported so as not to be separated along the inclined surface 5 ′, and the cutter holder 6 is orthogonal to the pipe core axis line with the axial movement of the slider 5, that is, the direction in which the cutter holder 6 approaches and separates toward the pipe inner surface. To slide reliably. When the cutter holder 6 approaches the inner surface of the pipe, the circular cutter blade 7 pivotally supported by the cutter holder 6 projects in a direction to cut into the inner surface of the pipe, and when separated, separates from the inner surface of the pipe and does not contact.

The inner cable 17 connected to the shaft member 19 formed on the base end side (the right side in FIG. 1) of the rotary shaft 4 is, together with the outer cable 16, a bendable coaxial drive cable having a required length. 15 are formed. The inner cable 17 is connected to a motor of an external drive mechanism (not shown), and the rotating power from the motor is transmitted to the rotating shaft 4 via the inner cable 17. At this time, the cylinder 2 and the cylinder cover 3 connected to the cylinder 2 are
Rotates with. A spring 10 is provided between the spring 10 and the cylinder 2.
The spring 10 elastically urges the rotary shaft 4 in the forward direction, and the spring 10 pulls the inner cable 17 connected to the rotary shaft 4 (direction B in FIG. 1).
To assist the return of the rotating shaft 4.

Based on the above configuration, the cutting operation of the pipe cutter is performed by transmitting the rotational force transmitted from the motor of the external drive mechanism to the rotary shaft 4 via the inner cable 17 and the slider 5 together with the cylinder 2, the cutter holder 6, While rotating the cutter blade 7 integrally, the rotating inner cable 17 is axially moved by a required stroke by a handle means (not shown), so that the cutter holder 6 is rotated.
And the cutter blade 7 can approach and separate toward the inner surface of the pipe.

At the time of the cutting operation, the rotary shaft 4 is configured to be movable in the axial direction with respect to the cylinder 2, so that the slider 5 moves in the retreating direction together with the rotary shaft 4 (FIG. 1).
In the direction B), and the cutter holder 6 is guided by the inclined surface 5 'by the backward movement of the slider 5,
Since the cutter blade 7 rotates and moves in a direction approaching the inner surface of the pipe P, the cutter blade 7 pivotally supported by the cutter holder 6 comes into contact with the inner surface of the pipe P to start cutting. At this time, the shaft member 1
8 moves in the retreating direction along with the movement of the slider 5, and the tapered portion 18 ′ of the shaft member 18 presses the mover 20 movably mounted on the cylinder 2 in the radial direction of the cylinder 2. At the same time, the shaft member 19 is
7 moves in the same retreating direction as it moves in the retreating direction, and the tapered portion 19 ′ presses the mover 20 movably mounted on the cylinder 2 in the radial direction of the cylinder 2.

Since the mover 20 is mounted movably in the radial direction of the cylinder 2, it is supported by the mover 20 on the cylinder circumference until the cutter blade 7 starts cutting into the inner surface of the pipe until the cutting operation is completed. Since the three rolling rollers 9 equally disposed in the cylinder 2 move in the radial direction of the cylinder 2 by the same degree, the cylinder 2 always rotates concentrically in the pipe.

After the cutting is completed, the rotating shaft 4 and the slider 5 are both moved in the forward direction by the urging force of the spring 10 by returning the inner cable 17 to the forward direction (direction A in FIG. 1) by handle means (not shown). To move the cutter holder 6 away from the inner surface of the pipe, and the cutter blade 7 separates from the inner surface of the pipe. Therefore, the pipe cutter body 1 is in a state where it can be pulled back inside the pipe.

In the above-described embodiment, three rolling rollers 9 are provided on the distal end side and the proximal end side of the cylinder 2, respectively. However, three or more rolling rollers 9 can be provided as necessary.

FIG. 5 shows an ammeter device 21 connected to a power supply circuit of a motor of an external drive mechanism (not shown). The ammeter device 21 includes a current value detecting indicator 25 that moves in response to a load at the time of cutting by the cutter blade, and a current value setting indicator 24 that sets a current value at the end of cutting in advance.
And a buzzer speaker 22 that issues an alarm when the current value detecting pointer 25 moves to a position corresponding to the current value setting pointer 24 due to a decrease in the current value at the end of cutting the pipe.
And Before starting the cutting operation, the current value at the end of the cutting is set in advance by the setting button 23.
After the start of cutting, a load is applied, so that the current value represented by the detection pointer 25 increases. When the cutting is completed, the load becomes lighter, and the current detection indicator 25 returns to the set value. When the current detection indicator 25 returns to the set value, it indicates that the cutting of the pipe has been completed. At that time, the buzzer speaker 22 of the ammeter device 21 sounds to notify the operator that the cutting is completed.

FIG. 6 is a circuit diagram schematically showing the current input / output terminal section 30 of the ammeter device 21. As shown in the figure,
Input terminals A and C provided in the current input / output terminal 30 are connected between the 100 V line of the commercial power supply and the motor M. AC power input terminals D and E of the current input / output terminal section 30 are adapted to receive 100 V of commercial power from a 100 V commercial power line. A terminal a is a terminal to which an ON signal by a switch T1 described later, which is turned on when the setting pointer 24 coincides with the detection pointer 25, is taken in, and a terminal b is a terminal where the setting pointer 24 coincides with the detection pointer 25. The terminal c is a terminal for outputting a driving current for sounding the buzzer speaker 22 at the time, and the terminal c is a terminal for detecting power fluctuating according to the load of the motor.

FIG. 7 is a circuit diagram showing a drive circuit for driving the buzzer speaker 22, the setting pointer 24, and the detection pointer 25, which are the constituent elements of the ammeter 21. On the line of the set pointer 24, there is a set button 23,
A switch T1 that is turned on when the reset pointer 24 matches the detection pointer 25 is interposed, and the buzzer speaker 22 sounds when the switch T1 is turned on.

[0034]

As described above, according to the present invention, even when the cutter blade cuts into the inner surface of the pipe step by step during the cutting operation, the rotation center of the cylinder does not change, and from the start of the cutting of the pipe to the end of the cutting. The cylinder always rotates concentrically in the pipe. Thereby, the resistance received by the cutter blade is constant from the time when the cutter blade starts cutting into the inner surface of the pipe until the cutting operation is completed. Therefore, the cutting noise at the start of pipe cutting becomes smaller than in the conventional example, and the cut surface of the pipe becomes uniform. Further, since the cylinder is always concentrically rotating within the pipe, damage due to vibration of the cutter blade can be avoided. Furthermore, the time required to cut pipes of the same diameter is greatly reduced, for example, the time required to cut pipes of the same diameter of 250 mm and 320 mm is less than that of the conventional example of 5-6 minutes. Only 30 seconds.

Further, since the ammeter device for notifying the completion of the cutting of the pipe cutter is provided, it is possible to avoid withdrawal of the pipe cutter in which the cutting operation is not completed due to a determination error. Then, when the disconnection is completed, the buzzer speaker sounds and notifies the operator that the disconnection is completed,
The motor power used for cutting work can be turned off immediately,
Not only power saving, but also immediate entry into the next construction phase, improving the overall efficiency of the construction.

[Brief description of the drawings]

FIG. 1 is a sectional view of a pipe cutter according to the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a sectional view taken along the line BB of FIG. 1;

FIG. 4 is a sectional view taken along line CC of FIG. 1;

FIG. 5 shows an ammeter device connected to a power supply circuit of a motor used for a cutting operation.

6 is a circuit diagram schematically showing a current input / output terminal section 30 of the ammeter device 21 shown in FIG.

7 is a circuit diagram showing a drive circuit for driving the buzzer speaker 22, the setting pointer 24, and the detection pointer 25 shown in FIG.

FIG. 8 is a sectional view showing a conventional pipe cutter.

FIG. 9 is a view taken along the line AA in FIG. 8;

FIG. 10 is a sectional view taken along the line BB of FIG. 8;

[Description of Signs] 1 Pipe cutter body 2 Cylinder 4
Rotary shaft 5 Slider 6 Cutter holder 7
Cutter blade 9 Rolling roller 16 Out cable 17
Inner cable 18 Shaft member 19 Shaft member 21
Ammeter device

──────────────────────────────────────────────────続 き Continued on the front page (56) References JP-A-4-339990 (JP, A) JP-A-3-180277 (JP, A) JP-A-3-19618 (JP, U) JP-A-3-19618 19620 (JP, U) Japanese Utility Model 3-65604 (JP, U) Japanese Utility Model 5-41631 (JP, U) Japanese Utility Model 5-16057 (JP, U) Japanese Utility Model 3-75865 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) B23D 21/14 E21B 29/08 F16L 55/18

Claims (2)

(57) [Claims] A cylindrical cylinder having an outer diameter capable of being inserted into a pipe to be cut, and an axially slidable cylinder located in the cylinder and rotating together with the cylinder in a rotational direction. A rotating shaft, a slider connected to the tip of the rotating shaft and having an inclined surface inclined with respect to the axial direction, and a slider supported in contact with the inclined surface of the slider and approaching the inner surface of the pipe by axial movement of the slider. , A cutter holder that slides in a separating direction, an inner cable of a drive cable having a required length is fixedly connected to a base end of the rotating shaft, and the drive cable is a ground opening of a pipe. The motor is connected to an external drive mechanism through the motor and the rotational force of the motor output shaft is transmitted to the inner cable, and the inner cable is given a forward and backward motion. In the pipe cutter, a plurality of rolling rollers that are in contact with the inner surface of the pipe pipe are equally arranged on the outer circumference of the cylinder on the circumference of the distal end portion and the base end portion, and the rolling rollers are A pipe cutter characterized in that it is movable so as to protrude in the radial direction of the cylinder when the rotating shaft is pulled backward, so that the cylinder always rotates concentrically in the piping pipe. 2. The external drive mechanism is provided with an ammeter device in a power supply circuit of a motor to which an inner cable is connected. The ammeter device has a current that moves in response to a load at the time of cutting by a cutter blade. The value detection pointer, the current value setting pointer that sets the current value at the end of cutting in advance, and the current value detection pointer due to the decrease in the current value at the end of cutting of the piping pipe corresponded to the current value setting pointer. 2. A pipe cutter according to claim 1, further comprising means for issuing an alarm when the movable part is moved to a position.