JPH09309005A - Cutting tool for plastic pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To cut an outer surface of a pipe end part from a large bore size to a small bore size, by providing a core pressed in the pipe end part, escape pawl meshed with a screw shaft by action of a spring, cutter mounted in an arm tip end jouranlled to a tool main unit and a spring energizing an arm. SOLUTION: A core 27 is strongly pressed in, deformation in a plastic pipe end part is corrected, after fixing the pipe end part, a driver tip end part of a power tool is fitted to an insertion port 22, a head part 31a is placed in a pipe end, the power tool is driven. Then, a tool main unit 24 is advanced to rotate around a screw shaft 25, an outer surface of the pipe end part is cut by a cutter 33. During cutting, by action of a spring 34, a stopper 36 is engaged with the screw shaft 25 and by action of a spring 30, returning back of the tool main unit 24 is impeded. A fixed length is cut, when an escape pawl 29 leads to a screw shaft end, the cutter 30 is raced in the same part, cutting is completed. Thereafter, when an arm 31 is gripped in, the cutter 33 is brought up, the stopper 36 is detached from the screw shaft 25.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used for cutting the outer surface of a plastic pipe end to be fused by being inserted into a pipe joint in the plumbing work such as water and sewer pipes and gas pipes using plastic pipes. Related to cutting tools.

[0002]

2. Description of the Related Art In piping work, various pipe joints such as socket joints, elbow joints, service joints, and cap joints are used to connect pipes. When these pipe joints and pipes are connected by plastic pipes, Generally, it is performed by heat fusion. Conventionally, heat fusion has been performed by heating and melting the outer surface of the plastic pipe end and the inner peripheral surface of the joint with a heater, and then inserting the pipe end into the joint. An electrofusion joint in which a heating wire is buried and heat fusion is performed by energization has been developed and put into service. In any case, it is necessary to remove dirt and foreign substances adhering to the outer surface of the plastic pipe in order to ensure proper heat fusion and not to impair the fusion strength. The surface of the pipe was cut in the direction of the pipe axis by using, or it was cut by fitting it into a plastic pipe and rotating it using a rotating planer. However, there are problems such as uncut material, uneven cutting depth, and roughened pipe surface after cutting.
If the pipe is crushed and deformed, or the outer diameter of the pipe changes, the blade can not follow the outer peripheral surface of the pipe, leaving uncut portion,
There is a problem that uneven cutting depth occurs.

In order to solve the above-mentioned problems, a core which is inserted into a pipe end portion to correct the deformation of the pipe end portion, and a core which is rotatable around the core and tiltable in a radial direction are supported. Various cutting tools have been proposed which consist of a spring that moves one pitch of a screw in the axial direction of the pipe and biases an arm with a cutter attached to the tip of the tip so that the cutter makes elastic contact with the outer surface of the pipe. There is.

FIG. 1 shows an example of this type of cutting tool disclosed in Japanese Unexamined Patent Publication No. 5-104301, in which a core 2 having a diameter smaller than the inner diameter of the plastic tube 1 and having a tapered enlarged head is shown. , A screw shaft 4 which is rotatably and slidably fitted in the shaft hole 3 of the core 2 and has a ratchet tooth shape.
And a relief claw 7 which is mounted in the recess 5 of the core 2 so as to be able to move forward and backward toward the screw shaft 4 and is biased by the action of the spring 6 so as to mesh with the screw shaft 4, and is fixed to the screw shaft 4. , And the nut 1 fixed to the output shaft 9 of the motor 8 on the extension of the screw shaft 4.
1, a tool body 12 having an insertion opening into which the tool 1 is fitted, and an arm 13 supported by the tool body 12 so as to be tiltable in a radial direction within a certain angle range and having a cutter 14 fixed to a head portion 13a at the tip thereof. , A spring 16 for urging the arm 13 to lower the tip, when the outer surface of the plastic pipe end is cut, the core 2 is strongly pushed into the plastic pipe end to correct the deformation of the pipe end. Then, after fixing to the pipe end, the nut 11 of the motor 8 is fitted into the insertion opening of the tool body 12, and the motor 8 is driven with the arm head 13a placed at the pipe end. It rotates around the axis of the screw shaft together with the shaft 4. And screw shaft 4 for each rotation
Is screwed into the core 2 by one pitch, and the cutter 1
4 is advanced to cut the outer surface of the plastic pipe end.

When the outer surface of the plastic pipe end is cut to a certain length and the cutting is finished, the tool body 12 is returned to its original position.
The escape claw 7 meshes with the screw shaft so that it can slide in one direction but cannot move in the opposite direction.
That is, the screw shaft 4 is prevented from moving to the left in the figure by the relief claw 7, but can move to the right, so when returning the screw shaft 4 can be returned by simply pulling out the tool body 12 to the right. You can When the tool body 12 is returned to the original state and further pulled out, the core 2 comes out from the pipe end.

[0006]

In the cutting tool described above, the diameter of the screw shaft needs to be increased to some extent to make it thick so as to have rigidity so that the screw shaft is not easily bent or deformed. The core to be inserted into must also have some rigidity,
Further, since it is necessary to attach the relief claw, the wall thickness becomes large and the outer diameter of the pressure core also becomes large. The above-mentioned cutting tool also has an advantage that when the tool body is returned to the original position after finishing the cutting, it does not need to be rotated in the opposite direction to that at the time of cutting, and can be returned to the original state by one-touch operation of simply pulling it out. It is necessary to pull out the cutting tool in order to return it to. A first object of the present invention is to make the outer diameter of the core arbitrary so that the outer surface of the end of the plastic pipe having a large diameter to a small diameter can be cut. Second of the present invention
The purpose of is to improve the cutting tool so that the tool body can be automatically returned to the original state.

[0007]

The invention for achieving the first object is to provide a tool main body, a screw shaft that is rotatably and slidably fitted in the tool main body, and has a screw thread having a ratchet tooth shape. A core that is protrudingly formed or fixed to the tip of the shaft and is pushed into the plastic pipe end, and a relief claw that is attached to the tool body so that it can advance and retract in the radial direction of the screw shaft and that meshes with the screw shaft by the action of the spring. It is characterized in that it comprises an arm pivotally supported in the tool body in a tiltable manner in the radial direction, a cutter attached to the tip of the arm, and a spring for urging the arm so that the tip moves downward. According to the present invention, the core can be formed to be larger than the screw shaft or to be smaller than the screw shaft regardless of the screw shaft, so that the core can be applied to a pipe having a large diameter to a small diameter.

According to the invention for achieving the second object, a core fixed by being pushed into an end portion of a plastic tube and a core is inserted into a shaft center of the core so as to be rotatable and slidable, and a shape of a screw thread. A ratchet toothed screw shaft, a relief claw that is attached to the core so that it can move forward and backward in the radial direction of the screw shaft, and engages with the screw shaft by the action of a spring, a tool body that is fixed to the screw shaft, and a tool body. In a cutting tool that is supported so as to be tiltable in the radial direction and has a cutter attached to the tip, and a spring that urges the arm so that the tip moves forward and downward, urge the screw shaft in the direction to pull it out from the core. Another invention is characterized in that a spring is provided, and a tool body, a screw shaft that is rotatably and slidably fitted in the tool body, and has a ratchet toothed thread shape, and a tip of the screw shaft. Plastic pipe tube end that is formed or fixed to the A core to be pushed in, a relief claw that is attached to the tool body so as to be able to move forward and backward in the radial direction of the screw shaft, and engages with the screw shaft by the action of a spring, and an arm that is axially supported by the tool body so as to be tiltable in the radial direction. In a cutting tool that consists of a cutter attached to the tip of the arm and a spring that urges the arm so that the tip moves forward and downward, a spring that urges the tool body in the direction of pulling out from the screw shaft is provided. Characterize.

According to each of the above-mentioned inventions, when cutting, the tool body is advanced by one rotation by one pitch of the screw of the screw shaft against the action of the spring to perform cutting, but the tool body is rotated. When it is stopped and the holding of the tool body is released, it is immediately returned by the action of the spring in the direction in which it is pulled out along the screw shaft. In each of the above inventions, as described above, it is necessary to continue to push the tool body against the action of the spring, and if it is not pushed continuously, the action of the spring causes the tool body to return. To solve this problem, during cutting when the arm tip goes down front, engage the stopper with the screw shaft to prevent the tool body from moving backward, and lift the arm tip at the end of cutting to stop the stopper. It is advisable to disengage from the screw shaft so that the screw shaft can be returned by the action of the spring.

Therefore, another preferred invention is provided with a stopper which engages and disengages with the screw shaft in association with tilting of the arm so as to engage with the screw shaft at the time of cutting and disengage from the screw shaft at the end of cutting. And In each of the above inventions, the rotation of the tool body may be performed manually, for example, the output shaft of the motor or the driver of the electric tool is connected to the tool body on the screw shaft or the extension of the screw shaft by a connecting member, preferably It may be detachably connected and may be performed by a motor or an electric tool.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The cutting tool shown in FIG. 2 has a bottomed shaft hole 21, a hexagonal insertion hole 22 into which the tip of a driver of an electric tool is inserted on an extension of the shaft hole 21, and a shaft hole. A tool body 24 having a recess 23 formed on the opening side of 21;
A screw shaft 25 that is rotatably and slidably inserted into the shaft hole 21 of the tool body 24 and has a ratchet toothed thread shape.
And a core 27 having a diameter smaller than the inner diameter of the plastic tube 26 to be inserted and formed at the tip of the screw shaft 25 and having a tapered expanding head, and a spring 28 in the recess 23 of the tool body 24. It is mounted, meshes with the screw shaft 25 by the action of the spring 28, rotates around the screw shaft 25, and
Along with the relief claw 29 movable in the pull-out direction, and the shaft hole 2
1, a spring 30 for urging the screw shaft 25 in a pushing direction, an arm 31 axially supported by the tool body 24 so as to be tiltable in a radial direction within a certain angle range, and a head portion of the arm tip. A cutter 33, which is detachably fixed to 31a by a set screw 32, has blades wider than the pitch of the screw of the screw shaft 25 and has a vertically symmetrical shape, and the tip of the arm 31 moves forward and downward. The spring 34 urges the arm 31 and a stopper 36 projectingly formed on the arm 31 and releasably engaged with the screw shaft 25.

When cutting the outer surface of the end of the plastic pipe, the core 27 is strongly pushed into the end of the plastic pipe to correct the deformation of the pipe end, and then fixed to the pipe end.
Insert the screwdriver tip of an electric tool (not shown) into the insertion port 22
And drive the electric tool with the head 31a placed at the tube end. Then, the tool main body 24 rotates around the screw shaft 25, and by one rotation, it moves forward by one pitch of the screw of the screw shaft 25, and the cutter 31 cuts the outer surface of the end of the plastic pipe. During cutting, the stopper 36 engages with the screw shaft 25 by the action of the spring 34, and prevents the tool body 24 from returning due to the action of the spring 30. When the relief claw 29 reaches the screw shaft end after cutting for a certain length, the cutter 31 cuts the same portion and continues idling, and the cutting ends. After that, when the arm 31 is grasped against the action of the spring 34,
The cutter 33 is lifted up and the stopper 36
Separates from the screw shaft 25. As a result, the tool body 24 moves back by the action of the spring 30 in the direction of being pulled out along the screw shaft 25, reaches the end of the screw shaft, and stops.

The cutting tool shown in FIG. 3 is different from the cutting tool shown in FIG. 1 in that a spring 41 is attached to the screw shaft 4 between the core 2 and the tool body 12, and the tool body 12 is separated from the core 2.
In addition, the screw shaft 4 is biased in a direction to be pulled out from the core 2, and the pulling out is performed by a stopper 42 provided at the end of the screw shaft.
Is performed until it hits the core 2.

[0014]

The present invention is configured as described above and has the following effects. According to the cutting tool of claim 1,
Since the core is not restricted by the screw shaft and can have any outer diameter, it can be applied to a pipe having a small diameter to a large diameter by changing the diameter of the core.
According to the cutting tool of the second and third aspects, when the cutting is finished and the holding to the tool body is released, the cutting tool automatically returns to the original position by the action of the spring. According to the cutting tool of claim 4, during cutting, the stopper engages the screw shaft to prevent the tool body from returning, so that it is necessary to continue to push the tool body against the action of the spring. Absent. When the arm is pushed in, the cutter lifts and the stopper separates from the screw shaft, and the tool body moves back by the action of the spring. In the cutting tool according to claim 5, cutting is performed manually, and in the cutting tool according to claim 6, electric cutting is performed. In the cutting tool according to claim 7, a motor or an electric tool used for other purposes is used. You can do the cutting work.

[Brief description of drawings]

FIG. 1 is a partial sectional view of a conventional cutting tool.

FIG. 2 is a sectional view of a cutting tool according to the present invention.

FIG. 3 is a partial sectional front view of another example of the cutting tool according to the present invention.

[Explanation of symbols]

1, 26 ... Plastic tubes 2, 27 ...
Core 3, 21, ... Shaft hole 4, 25 ...
Screw shafts 5, 23 ... Recesses 6, 16, 28, 30, 34, 41 ... Spring 7, 29 Relief claws 8 Motor 9 Output shafts 11 Nuts 24 24 Tool body 13, 31
・ Arms 14, 33 ・ ・ Cutters 22 ・ ・ Insertion ports 36, 42 ・ ・ Stoppers

Claims (7)

[Claims] Claim: What is claimed is: 1. A tool body, a threaded shaft which is rotatably and slidably fitted into the tool body, and has a ratchet tooth-shaped screw thread, and is formed or fixed to a tip of the threaded shaft so as to project or be fixed. The core is pushed into the end, the tool body is attached so that it can move forward and backward in the radial direction of the screw shaft, the relief claw that meshes with the screw shaft by the action of the spring, and the tool body is pivotally supported so that it can tilt in the radial direction. A cutting tool for a plastic pipe, comprising: an arm, a cutter attached to the tip of the arm, and a spring for urging the arm so that the tip moves downward. 2. A plastic main body, a plastic body which is rotatably and slidably fitted into the main body of the tool, and a screw shaft whose screw thread has a ratchet tooth shape, and which is projected or fixed to the tip of the screw shaft. The core is pushed into the end, the tool body is attached so that it can move forward and backward in the radial direction of the screw shaft, the relief claw that meshes with the screw shaft by the action of the spring, and the tool body is pivotally supported so that it can tilt in the radial direction. In a cutting tool consisting of an arm, a cutter attached to the tip of the arm, and a spring that urges the arm so that the tip moves forward and downward, a spring that urges the tool body in the direction of pulling out from the screw shaft is provided. A cutting tool for plastic pipes. 3. A plastic pipe, which is pressed into and fixed to the end of a plastic pipe, a screw shaft which is rotatably and slidably fitted into the core of the core, and has a screw thread shape of ratchet teeth, and a core. Is attached to the screw shaft so as to be able to advance and retreat in the radial direction of the screw shaft, a relief claw that meshes with the screw shaft by the action of a spring, a tool main body fixed to the screw shaft, and supported by the tool main body so as to be tiltable in the radial direction,
In a cutting tool consisting of an arm having a cutter attached to the tip and a spring for urging the arm so that the tip goes down forward, a spring for urging the screw shaft in the direction of pulling out from the core is provided. Cutting tool for plastic pipes. 4. A stopper which engages and disengages with the screw shaft in association with tilting of the arm is provided so as to engage with the screw shaft at the time of cutting and disengage from the screw shaft at the end of cutting. Alternatively, the plastic pipe cutting tool according to the item 3. 5. The cutting tool for plastic pipes according to claim 1, wherein the tool body is manually rotated. 6. A motor or an electric tool is connected to the tool body, and the tool body is electrically rotated.
A plastic pipe cutting tool according to any one of claims 1 to 4. 7. The plastic pipe cutting tool according to claim 6, wherein the motor or the power tool is removable.