JP2006110670A - Existing pipe cutting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an existing pipe cutting device, returning a cutting tool to the initial position without applying heavy load and without taking extra time in the case of returning the cutting tool to the initial position after cutting the existing water line pipe. <P>SOLUTION: A cutting unit 3 includes: a stepping screw part 16 moving forward and backward the cutting tool 19 in the radial direction of the existing water line pipe P and rotatable around a first rotating shaft C1 disposed in the radial direction; a passive rotating part 18 rotatable around a second rotating shaft C2 driven by a kicker part fixedly disposed in the vicinity of a cutting path of the cutting unit 3; and a decelerating means for applying the rotation corresponding to a unit feed amount to the stepping screw part 16 with deceleration by the passive rotating part 18, wherein the first rotating shaft C1 and the second rotating shaft C2 are disposed in parallel to each other. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an existing pipe cutting device that cuts an existing pipe in an undisturbed water state in a casing in which a part of the existing pipe such as a water pipe is sealed in a watertight manner, and more specifically, the existing pipe is cut along the circumferential direction. The present invention relates to an existing pipe cutting device that includes a cutting unit that includes a cutting tool that cuts, a guide unit that holds the cutting unit, and a drive unit that rotationally drives the cutting unit.

  A conventional existing pipe cutting device is a passive unit driven by a stepping screw part that enables the cutting unit to advance and retract the cutting tool in the diameter direction of the existing pipe, and a kicker part that is fixedly arranged near the cutting path of the cutting unit. The rotation part, the rotation axis of the stepping screw part and the rotation axis of the passive rotation part are arranged in the orthogonal direction, and the rotation of the passive rotation part driven by the kicker part is decelerated by a worm and a worm wheel as a speed reduction means. The step screw portion is rotationally transmitted (for example, see Patent Document 1).

Japanese Patent No. 3294165 (second page, FIG. 2)

  However, in Patent Document 1, when cutting an existing pipe with an existing pipe cutting device and then returning the cutting bite to its original position, a worm and a worm wheel are used as a deceleration means, and therefore, an advance screw When the part is directly rotated in the reverse direction, a large load is required, and when the rotational passive part is rotated in the reverse direction, an extra rotation quantity corresponding to the reduction ratio is required, which takes time and labor.

  The present invention has been made paying attention to such problems, and when cutting the existing pipe and returning the cutting bite to the original position, without applying a heavy load and extra time. The purpose is to return to the original position.

In order to solve the above-described problem, an existing pipe cutting device according to claim 1 of the present invention includes a peripheral wall of the existing pipe along a circumferential direction in a casing in which a part of the existing pipe is watertightly sealed. An existing pipe cutting device comprising a cutting unit having a cutting tool capable of cutting, a guide part capable of rotatably holding the cutting unit in the circumferential direction, and a drive part for rotationally driving the cutting unit. The cutting unit is capable of moving the cutting bite in the diametrical direction of the existing pipe and a stepping screw portion rotatable around the first rotation axis disposed in the diametrical direction, and the cutting unit. A passive rotating part that can be rotated around a second rotation axis driven by a kicker part fixedly arranged in the vicinity of the cutting path, and the passive rotating part decelerates the rotation corresponding to the unit feed amount to the stepping screw part. From the speed reduction means Ri, and the first rotary shaft and said second rotary shaft is characterized in that it is arranged in parallel.
According to this feature, since the stepping screw portion and the passive rotating portion are arranged in parallel and meshed with each other, a rotating transmission member such as a worm is not necessary, so that the cutting bit is moved to the original position after cutting the existing pipe. In the case of returning to, the first rotating shaft can be directly reversed, which can be reduced from the load caused when the rotating power transmission member such as a worm is reversed.

The existing pipe cutting device according to claim 2 of the present invention is the existing pipe cutting device according to claim 1, wherein the existing pipe can be cut in two cross sections, and the width between the two cross sections is wide. A pair of the cutting units are provided so as to have a narrow taper shape from the upper part to the lower part of the existing pipe.
According to this feature, when the pipe piece between two cross sections is lifted and removed from above after cutting the existing pipe, the width between the faces of the pipe piece becomes a narrow taper from the top to the bottom. Therefore, the cut surfaces of the pipe piece and the existing pipe are not in sliding contact, and the pipe piece can be easily removed. In particular, the pipe piece can be removed smoothly without the cutting tool coming into contact with the existing pipe while the pipe piece is being lifted.

The existing pipe cutting device according to claim 3 of the present invention is the existing pipe cutting device according to claim 2, wherein the pair of cutting units can cut the existing pipe into the tapered shape. The cutting unit is preliminarily held in the tapered shape so that
According to this feature, since the pair of cutting units are rotatable while being held in a tapered shape in advance, the existing pipe can be reliably cut into a tapered shape.

The existing pipe cutting device according to a fourth aspect of the present invention is the existing pipe cutting device according to any one of the first to third aspects, wherein the kicker portion is a kicker piece that can drive the passive rotating portion. Thus, the kicker piece is characterized in that it can move between a driving position where the passive rotating portion comes into contact with and engages with the passive rotating portion and a retracted position where the passive rotating portion does not come into contact with and engage with the passive rotating portion.
According to this feature, since the kicker piece does not come into contact with and engage with the passive rotating part by retracting to the retracted position, when the cutting unit is trial rotated, the passive rotating part is driven by the kicker piece and cut. The trial rotation of the cutting unit can be performed smoothly without the progress of the cutting tool.

An existing pipe cutting device according to a fifth aspect of the present invention is the existing pipe cutting device according to any one of the first to fourth aspects, wherein the stepping screw portion is attached to the deceleration means by a predetermined load. A load member that enables stepping is provided.
According to this feature, in the cutting process of the existing pipe, since the cutting bit can receive the force in the backward direction by the sliding contact with the outer peripheral wall of the existing pipe by the load member, the cutting position of the cutting bit is maintained. Is possible.

  Examples of the present invention will be described below.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings. First, FIG. 1 is a front view showing an overall image of an existing pipe cutting device 1 in a first embodiment of the present invention. FIG. 2 is a side view showing an overall image of the existing pipe cutting device 1. Fig.3 (a) is a front view which shows the whole cutting | disconnection unit 3, (b) is a top view similarly. FIG. 4 is a side view showing the entire kicker unit 30 and the cutting unit 3. FIG. 5 is an enlarged front view showing members around the first rotation axis C <b> 1 and the second rotation axis C <b> 2 of the cutting unit 3. 6 is an AA plan view showing the load member of FIG. FIG. 7 is a diagram showing a situation in which the pipe piece P1 and the cutting unit 3 after being lifted are lifted above the housing 2. As shown in FIG.

  The apparatus outline of the existing pipe cutting apparatus 1 according to the present embodiment will be described. As shown in FIGS. 1 and 2, the cutting pipe 3 includes a cutting unit 3, a guide part 4, and a driving part 5. In the case 2 which is sealed, the guide portion 4 having a vertically divided structure is fixed and held on the outer peripheral surface of the existing water pipe P.

  A driving unit 5 including a driving motor 6 and a pair of driving sprockets 8 provided at both ends of a driving shaft 7 driven by the driving motor 6 is connected to the upper portion of the guide unit 4. The housing 2 protrudes from the outside.

  A pair of driven sprockets 9 having a vertically divided structure and rotatable in the outer peripheral direction of the existing water pipe P are disposed at both ends of the guide portion 4.

  As shown in FIG. 4, fixing rings 35 protrude from the both ends of the guide portion 4 around the outer periphery of the existing water pipe P. A recessed portion that can be fitted to the fixing ring 35 is formed on the back surface of the driven sprocket 9, and the driven sprocket 9 is fitted to the fixing ring 35 so as to be slidable around the pipe axis of the existing water pipe P. .

  A rear ring 36 is integrated with the driven sprocket 9 by a back retaining bolt 37 on the rear surface of the driven sprocket 9 fitted to the fixed ring 35, and the driven sprocket 9 is held so as not to fall off the fixed ring 35. However, it can rotate around the pipe axis of the existing water pipe P.

  As shown in FIG. 2, the pair of driven sprockets 9 are respectively connected to the pair of upper drive sprockets 8 via a wound endless chain 10 and are given rotational force by driving the drive sprockets 8. Circulate the outer periphery of the water pipe P.

  Further, the cutting units 3 are fixedly disposed at four positions at equal intervals on the outer surfaces of the pair of driven sprockets 9 so that the outer periphery of the existing water pipe P can be rotated along with the rotation of the driven sprocket 9. It can be cut around.

  As shown in FIG. 7, after cutting the existing water pipe P, the pipe piece P1 and the existing pipe cutting device 1 can move up and down in the work cylinder 2c installed at the upper part of the housing 2 (not shown). A new water pipe, a gate valve or the like is provided in the path of the existing water pipe P after being removed from the opening 2b that is openable and closable provided in the upper part of the housing 2 by the holding lifting device and removing the pipe piece P1. Will be installed and installed.

  In addition, the unloading process from the inside of the housing 2 is performed by closing the on-off valve 2a after lifting the unloaded material (the pipe piece P1 and the existing pipe cutting device 1) into the upper work cylinder 2c in the housing 2. The fluid in the existing water pipe 1 does not leak to the outside of the housing 2 and can be carried out in an undisturbed water state. As a matter of course, the carrying-in work is the reverse of the carrying-out work.

  The cutting unit 3 of this embodiment will be described in detail. As shown in FIG. 3A, a base material 11 is fixedly disposed on the outer surface of the driven sprocket 9, and a shaft support 13 is provided on the upper portion of the base material 11. It is fixedly connected.

  The shaft support 13 includes a stepping screw portion 16 that rotates about the first rotation axis C1 and a passive rotation portion 18 that rotates about the second rotation axis C2, which are parallel to each other and the pipe shaft of the existing water pipe P. It is pivoted toward the center.

  As shown in FIG. 3B, the passive rotating body 21 is provided with rotating blades 21a radially at a predetermined angular interval around the second rotation axis C2.

  Further, as shown in FIGS. 3 and 5, a fitting piece 22 and a second spur gear 23 that rotate about the second rotation axis C <b> 2 are disposed below the passive rotating body 21. Since the first spur gear 15 and the second spur gear 23 rotating around the first rotation axis C1 are meshed with each other, the first rotation axis C1 and the second rotation shaft C2 rotate synchronously. ing.

  Below the first spur gear 15, a slide frame 17 having a substantially trapezoidal shape in plan view, in which a female screw is disposed and a stepping screw 14 is screwed, is provided with a gap having a substantially trapezoidal shape in plan view. Thus, it is inserted in the space of the slide base 12 fixedly arranged at the lower part of the shaft support.

  Further, a front opening U-shaped fitting portion is provided on the front surface of the slide frame 17 so that the cutting tool 19 can be fitted into the fitting portion and fixed with the fixing bolt 17a. The cutting work 19 can be easily replaced when the tip blade 19a is worn.

  Accordingly, when the first rotation shaft C1 rotates forward and backward, the slide frame 17 to which the stepping screw 14 is screwed can be slid up and down along the slide base 12, and is thus fitted into the slide frame 17. The cutting tool 19 can be slid up and down toward the center of the pipe axis of the existing water pipe P.

  Further, since the first spur gear 15 and the second spur gear 23 are connected via a constant reduction ratio, the rotation angle of the first rotation shaft C1 is smaller than the rotation angle of the second rotation shaft C2.

  Therefore, even if an error in the rotation angle occurs during the rotation of the second spur gear 23, the error in the rotation angle of the first spur gear 15 is reduced by the reduction ratio, so that the accuracy of the unit feed amount of the cutting tool 19 is increased. be able to.

  Furthermore, the reduction ratio of the first spur gear 15 and the second spur gear 23 is arbitrarily set according to the outer diameter and thickness of the existing water pipe P to be cut or the material of the ductile cast iron pipe, steel pipe, etc. The unit feed amount of the byte 19 can be changed.

  Further, as shown in FIG. 2, a kicker portion 30 is fixedly disposed on the outer surface of the guide portion 4 in the vicinity of the cutting path of the cutting unit 3 that rotates around the outer periphery of the existing water pipe P. As shown in FIG. 4, a kicker piece 31 projects from the kicker portion 30 toward the cutting path of the lower cutting unit 3.

  Therefore, as shown in FIG. 4, when the cutting unit 3 that rotates around the outer periphery of the existing water pipe P passes through the vicinity of the kicker section 30, the rotation of the passive rotating body 21 that is pivotally supported by the second rotating shaft C <b> 2. The blade 21a is brought into contact with and engaged with the kicker piece 31, and the rotary blade 21a rotates by a predetermined amount (forward rotation) until the cutting unit 3 finishes passing through the vicinity of the kicker portion 30 and the engagement is released. Become.

  That is, after a predetermined amount of rotation (forward rotation) on the second rotation shaft C2 is transmitted to the first spur gear 15 that meshes with the second spur gear 23 that is also supported by the second rotation shaft C2, and then decelerated. The first rotating shaft C1 rotates by a certain amount, and the cutting tool 19 fixed to the slide frame 17 moves downward by an amount.

  Therefore, every time the cutting unit 3 rotates on the outer circumference of the existing water pipe P and passes through the kicker section 30, the rotary blade 21a of the passive rotating body 21 abuts and engages with the kicker piece 31 and rotates by a predetermined amount. When the cutting tool 19 moves downward by an amount per unit, the tip blade of the cutting tool 19 rotates the outer periphery while cutting the outer peripheral wall of the existing water pipe P by a certain amount to cut the existing water pipe P.

  In this embodiment, as shown in FIGS. 5 and 6, a load member 20 is provided that applies a load to the rotation of the first rotation shaft C <b> 1 and the second rotation shaft C <b> 2. A fitting piece 22 is provided which is pivotally supported by the second rotation axis C2 and in which a recess 22a is formed on the second rotation axis C2 around the second rotation axis C2 at a predetermined angular pitch toward the outer periphery in plan view.

  On the other hand, the shaft support 13 in the vicinity of the fitting piece 22 has a screw insertion hole 24 provided with a female screw on the inner peripheral surface, and a screw having an inner space in which a male screw is provided on the outer peripheral surface and one end is opened. The insert 27 is screwed. A spring body 25 and a ball body 26 are inserted into the inner space of the screw insertion body 27, and the ball body 26 positioned at the one open end of the screw insertion body 27 is fitted by the elastic force of the spring body 25. The piece 22 is pressed and urged, and is fitted into the recess 22 a of the fitting piece 22.

  A square hole 27a is provided at the other end of the screw insertion body 27 separately from the internal space, and the screw insertion body is screwed into the shaft support 13 with a square wrench or the like corresponding to the square hole 27a. By removing 27, the screw insert 27 can be replaced as appropriate.

  Therefore, since the rotational load force with respect to the 2nd rotating shaft C2 can be adjusted by selecting the screw insertion body 27 of the specification from which pressing urging | biasing force differs, with respect to the resistance force concerning the cutting bit 19 at the time of the cutting of the existing water pipe P The holding force can be adjusted.

  Further, by adjusting the screw insertion position of the screw insertion body 27 with the square wrench or the like, the force with which the spring body 25 presses and urges the ball body 26 against the recess 22a can be adjusted.

  As shown in FIGS. 4 to 6, when the rotary blade 21 a of the passive rotating body 21 rotates by a predetermined amount by contact engagement with the kicker piece 31, the fitting piece 22 supported by the second rotary shaft C <b> 2 is also provided. Similarly, the ball body 25 is rotated by a predetermined amount, and the ball body 25 is fitted into the concave portion 22a that faces after the fitting piece 22 rotates by the predetermined amount.

  That is, since the fitting piece 22 pivotally supported by the second rotation shaft C2 is held by the ball body 26 pressed and biased by the spring body 25 after rotating by a predetermined amount, the fitting piece 22 rotates integrally with the second rotation shaft C2. The cutting tool 19 fixed to the first rotating shaft C1 is held at a point where the amount per unit is lowered.

  Therefore, when cutting the existing water pipe P, the cutting tool 19 applies a force in the backward direction by sliding contact with the outer peripheral wall of the existing water pipe P, and the fitting piece 22 is engaged with the ball body 26 and the recess 22a. Since it can be received, the cutting position of the cutting tool 19 can be held without the first rotating shaft C1 and the second rotating shaft C2 rotating in reverse.

  Naturally, since the recess 22a formed in the fitting piece 22 and the rotary blade 21a provided in the passive rotating body 21 are provided at the same predetermined angular interval, when the existing water pipe P is cut. , The concave portion 22a facing the ball body 26 is fitted at a point where the rotary blade 21a has been rotated by a predetermined amount by the kicker piece 31, so that it is ensured at a point where the amount per unit given by the predetermined amount of rotation is lowered. The cutting tool 19 is held.

  In this embodiment, as shown in FIG. 1, four types of cutting units 3 are fixedly arranged on the outer surfaces of the pair of driven sprockets 9 at equal intervals. At this time, since the trajectory drawn by the tip edge 19a of each cutting bit 19 is the same, each cutting bit 19 cuts the existing water pipe P while cutting the same cutting groove in the existing water pipe P.

  Further, in this embodiment, as shown in FIG. 2, the pair of driven sprockets 9 provided at both ends of the guide portion 4 are tapered so that the inter-surface width increases from the upper part to the lower part. Since it is formed, the two cut surfaces of the existing water pipe P cut by the cutting unit 3 rotating along the pair of driven sprockets 9 are formed in the same tapered shape.

  Therefore, as shown in FIG. 7, after the cutting operation of the existing water pipe P by the cutting unit 3 is completed, the pipe piece P1 between the cut surfaces, the guide portion 4 fixed and held on the outer periphery of the pipe piece P1, and the cutting unit When the cutting tool 19 provided on the outer surface of the driven sprocket 9 is engaged with the cut surface of the existing water pipe P after being cut, it is smooth without being disturbed. Can be carried out to

  As shown in FIG. 4, in this embodiment, the upper part of the kicker piece 31 is pivotally supported by the turning shaft 32, and the abutting portion 31 a of the kicker piece 31 can be turned upward. When the kicker piece 31 is rotated upward, the driven sprocket 9 can be rotated without the contact portion 31 a and the rotary blade 21 a being in contact with each other, and the cutting tool 19 is rotated by forward and reverse rotation of the driven sprocket 9. Therefore, the driven sprocket 9 can be trial-rotated before the cutting operation of the existing water pipe P, for example.

  Further, since the kicker piece 31 is held by the set screw 33 at the contact position where the kicker piece 31 comes into contact with the passive rotating body 21, the contact portion 31a of the kicker piece 31 and the rotary blade 21a are driven by the rotation of the driven sprocket 9. , The kicker piece 31 is not rotated upward.

  As shown in FIG. 1, a shock absorber that suppresses vibrations caused by the rotation of the endless chain 10 at two places on the circulation path of the endless chain 10 that is wound between the drive sprocket 8 and the driven sprocket 9 and circulates. 39 is provided, and the endless chain 10 that goes around passes through the buffer 39.

  In particular, while the drive shaft 7 of the drive sprocket 8 is parallel to the tube axis of the existing water pipe P, the driven shaft of the driven sprocket 9 has an existing water pipe so that the pair of driven sprockets 9 are tapered. Since it is provided obliquely with respect to the tube axis of P, it is possible to suppress the possibility of vibrations that are likely to occur in the endless chain 10 or dropping from the drive sprocket 8 and the driven sprocket 9.

  As shown in FIGS. 1 and 2, the guide portion 4 has an adjustment bolt 38 that presses and holds the outer peripheral wall from the outer surface toward the pipe axis direction of the existing water pipe P. A pair is arranged in the vicinity of the pair of driven sprockets 9 at equal intervals in the direction (eight places in this embodiment), and the adjustment bolts 38 are screwed from the outer surface to press the outer peripheral wall of the existing water pipe P. This makes it possible to adjust the tube axis of the existing water pipe P and the driven shaft of the driven sprocket 9.

  Further, as shown in FIG. 3A, after the cutting operation of the existing water pipe P is completed, the cutting tool 19 is moved upward by reversing the first rotating shaft C1, and the cutting unit 3 is cut. Release from the surface. In this case, since the first rotation axis C1 and the second rotation axis C2 are arranged in parallel, the stepping screw upper end 14a provided at the upper end portion of the first rotation axis C1 can be directly reversely rotated. For example, it is possible to reduce the load generated when the rotary transmission member such as a worm is reversed.

  Although the embodiments of the present invention have been described with reference to the drawings, the specific configuration is not limited to these embodiments, and modifications and additions within the scope of the present invention are included in the present invention. It is.

  For example, in the above-described embodiment, as shown in FIGS. 5 and 6, the fitting piece 22 that is pivotally supported by the second rotation shaft C <b> 2 serves as the load means of the stepping screw portion 14. Are provided separately from the spur gears 15 and 23 that connect the two, but they are not necessarily provided separately, and as a load means, a ball body that is always pressed and urged by the fitting piece 22 and the spring body 25 is used. There is no need by fitting with 26. For example, a cutting bit 19 is provided when cutting the existing water pipe P by a leaf spring, one end of which is fixedly held by the guide part 4 being pressed and latched by pressing a part of the uneven tooth part of the spur gear. The cutting position of the cutting tool 19 may be held by receiving a force in the backward direction by sliding contact with the outer peripheral wall of the water pipe P.

  In the above embodiment, as shown in FIG. 1, one driven sprocket 9 is provided with four types of cutting units 3, but if the existing water pipe P can be cut, the number of cutting units 3 Is not limited to four types, for example, only one type may be provided, or five or more types may be provided.

  Moreover, in the said Example, although the existing water pipe P was a water pipe, the internal fluid of an existing pipe may be liquid, such as water and sewage, or gas, such as gas.

  Moreover, in the said Example, although the existing pipe cutting device 1 was installed in the housing | casing 2 sealed watertight, and the existing water pipe P was cut | disconnected in the state of unrestricted water, The existing water pipe P may be cut in an open space without being limited to cutting the water pipe P.

  In the above embodiment, as shown in FIG. 5, the first spur gear 15 and the second spur gear 23 that connect the first rotary shaft C1 and the second rotary shaft C2 are connected so as not to be separated from each other. However, it is not necessarily limited to a connection method that cannot be separated. For example, one spur gear may have a clutch mechanism that is slidable in the direction of the rotation axis and can be separated from the other gear, and after the existing water pipe P is cut, the clutch is turned off and the first rotation shaft If only C1 is rotated in the reverse direction, the ascending operation of the cutting tool 19 is further facilitated without being loaded by the loading means.

  Moreover, in the said Example, as FIG. 1 shows, although the kicker part 30 is arrange | positioned 2 sets near the cutting | disconnection path | route of one side, it is not necessarily 2 sets, The existing water pipe P Depending on the material of the ductile cast iron pipe or steel pipe, for example, only one set may be provided, or three or more sets may be provided.

  Further, in the above embodiment, two sets of kickers 30 are arranged in the vicinity of the cutting path on one side, so that each time the cutting unit 3 makes a round around the existing water pipe P, the two sets of kickers 31 are used. Although the passive rotating body 21 was driven twice, only one kicker piece 31 is disposed at the driving position, for example, depending on the material of the ductile cast iron pipe or steel pipe of the existing water pipe P, and the other kicker piece 31 is The stepping amount of the cutting tool can be adjusted by arranging the cutting tool at the retracted position.

It is a front view which shows the whole image of the existing pipe cutting device 1 in 1st Embodiment of this invention. It is a side view which shows the whole image of the existing pipe cutting device 1 similarly. (A) is a front view which shows the whole cutting | disconnection unit 3, (b) is a top view similarly. It is a side view which shows the kicker part 30 and the whole cutting unit 3. FIG. 4 is an enlarged front view showing members around a first rotation axis C1 and a second rotation axis C2 of the cutting unit 3. FIG. It is an AA top view which shows the load member 20 of FIG. It is a figure which shows the condition which lifts the pipe piece P1 after cutting | disconnection, and the cutting | disconnection unit 3 above the housing | casing 2. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Existing pipe cutting device 2 Case 2a On-off valve 2b Opening 2c Work cylinder 3 Cutting unit 4 Guide part 5 Drive part 6 Drive motor 7 Drive shaft 8 Drive sprocket 9 Driven sprocket 10 Endless chain 11 Base material 12 Slide base 13 Base 14 Stepping screw 14a Stepping screw upper end 15 First spur gear 16 Stepping screw portion 17 Slide frame 17a Fixing bolt 18 Passive rotating portion 19 Cutting tool 19a Tip blade 20 Load member 21 Passive rotating body 21a Rotary blade 22 Fitting piece 22a recess 23 second spur gear 24 screw insertion hole 25 spring body 26 ball body 27 screw insertion body 27a square hole 30 kicker part 31 kicker piece 31a contact part 32 rotating shaft 33 set screw 35 fixing ring 36 back ring 37 back stop Bolt 38 Adjustment bolt 39 Buffer C1 First rotating shaft C2 Second rotating shaft P Existing water pipe P1 Pieces

Claims (5)

A cutting unit provided with a cutting tool capable of cutting the peripheral wall of the existing pipe along the circumferential direction in a case where a part of the existing pipe is sealed in a watertight manner, and the cutting unit can be rotated in the circumferential direction. An existing pipe cutting device comprising a guide portion that can be held in a drive unit and a drive unit that rotationally drives the cutting unit,
The cutting unit includes a stepping screw portion that is capable of moving the cutting tool back and forth in the diameter direction of the existing pipe and is rotatable about a first rotation axis disposed in the diameter direction, and a cutting path of the cutting unit. A passive rotating part that can be rotated around a second rotation axis that is driven by a kicker part that is fixedly disposed in the vicinity, and a rotation corresponding to a unit feed amount is decelerated and applied to the stepping screw part by the passive rotating part. An existing pipe cutting device, wherein the first rotating shaft and the second rotating shaft are arranged in parallel.   A pair of the cutting units are provided so that the existing pipe can be cut in two cross sections, and the width between the surfaces of the two cross sections becomes a narrow taper from the top to the bottom of the existing pipe. The existing pipe cutting device according to claim 1, wherein the existing pipe cutting device is provided.   The existing pipe according to claim 2, wherein the guide portion holds the cutting unit in a tapered shape in advance so that the pair of cutting units can cut the existing pipe in the tapered shape. Cutting device.   The kicker portion includes a kicker piece capable of driving the passive rotating portion, and the kicker piece is in contact with and engaged with the passive rotating portion so that the passive rotating portion can be driven, and does not contact with and engage with the passive rotating portion. The existing pipe cutting device according to any one of claims 1 to 3, wherein the existing pipe cutting device is movable between a retracted position and a retracted position.   The existing pipe cutting device according to any one of claims 1 to 4, wherein the speed reducing means is provided with a load member capable of stepping the stepped screw portion with a predetermined load.

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