JP3501525B2 - Pipe cutting machine - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a pipe cutting machine.
More specifically, the present invention relates to a pipe cutting machine that uses a metal saw to cut a workpiece such as a pipe or a rod while rotating the workpiece.

Conventionally, for gas pipes and water pipes, plastic-lined steel pipes whose inner or outer circumferences are lined with a plastic such as polyethylene are often used for the purpose of anticorrosion. A roller blade type cutter is generally used for cutting such a plastic-lined steel pipe, but it has a drawback that a so-called “burr” of the plastic is likely to occur on the cut surface and a clean cut surface cannot be obtained.
For this reason, pipe cutting machines using metal saws that do not cause "burrs" are now used.

[0003]

2. Description of the Related Art FIG. 4 is a view showing a conventional portable pipe cutting machine. In this, a chuck 2 which is rotationally driven by a motor (not shown) is attached to a head portion 1a of a frame 1 by a horizontal shaft. The chuck 2 and the horizontal shaft have a hollow central portion so that a workpiece 3 such as a pipe can be inserted from the rear to the front and can be bitten by a claw 2a provided on the chuck 2. .

On the front side of the frame 1, there is provided a metal saw support arm 4 whose one end is swingably supported by a horizontally-supported support shaft (not shown), and the metal saw support arm 4 is provided with a metal saw 5. It is provided. The metal saw 5 is the drive unit 6 of the metal saw support arm.
It is adapted to be rotationally driven by a motor provided in. Reference numeral 7 in the figure denotes a thread cutting head supported by two guide shafts 8.

[0005]

In the above conventional pipe cutting machine, in the case of being portable, the power source for driving the metal saw may be shared with the motor for driving the chuck in order to reduce the weight. In such a case, the metal saw supporting arm is lightened by the weight of the removed metal saw driving motor, so that there is a problem that the pressing force of the metal saw on the work material is insufficient when cutting the work material.

In view of the above conventional problems, it is an object of the present invention to realize a pipe cutting machine which eliminates the insufficient pressing force of a metal saw when cutting a work piece.

[0007]

In a pipe cutting machine according to the present invention, a frame, a chuck attached to a horizontal rotary shaft provided in a head portion of the frame and holding a work material, A metal saw that cuts a workpiece held by a chuck, a metal saw support arm that supports the metal saw, and is pivotally supported at a position away from the central axis of the metal saw, and rotationally drives the chuck and the metal saw. In the pipe cutting machine including one motor, a disk-shaped cam having a notch in a part of its outer circumference is formed so that its center coincides with the center of the support shaft of the metal saw support arm. While being fixed to the metal saw support arm, the frame is provided with a pressing member that can be engaged with and disengaged from the notch of the cam, and a spring that urges the pressing member.
At the position where the metal saw cuts the workpiece, the pressing member presses the notch of the cam to press the metal saw against the workpiece, and when not cutting, the pressing member escapes from the notch of the cam and It is characterized in that it is configured to release the pressing on the work material.

In addition to the above, a means for adjusting the urging force of a spring for urging the pressing member provided on the frame is provided.

[0009]

In the present invention, as shown in FIG. 2, the metal saw support arm 15 has a notch 1 at the same center as the center of its support shaft.
A disc-shaped cam 17 having 8 is attached, and the notch 1
By pressing 8 by the pressing means 19 provided on the frame 10, the metal saw support arm 15 is urged to rotate in the direction of arrow A, the metal saw 16 is pressed against the workpiece 12, and the notch of the metal saw 16 is cut. It can be automated. The pressing force can be adjusted by adjusting the spring receiver 23 up and down to change the mounting length of the spring 22.
The pressing force can be adjusted by changing the urging force to the.

If the attachment length of the spring 22 is kept constant, the larger the diameter of the workpiece 12 becomes, the larger the metal saw 1 becomes.
The pressing force of 6 will increase. When the metal saw support arm 15 is retracted from the work piece 12, as shown in FIG. 3, the tip of the pressing member 20 comes out of the notch 18 of the disk-shaped cam 17 and comes into contact with the circumferential portion. Therefore, the rotational force applied to the metal saw support arm 15 becomes zero, and the brake is simply applied. Therefore, the metal saw support arm 15 can be stopped at any position.

[0011]

1 and 2 are views showing an embodiment of the present invention.
FIG. 1 is a perspective view, and FIG. 2 is a cross-sectional view of essential parts. In this embodiment, as shown in FIG. 1, the work piece 1 is attached to a horizontal shaft which is rotationally driven by a motor (not shown) provided on a head 11 of a frame 10.
A chuck 13 that holds 2 is attached. A metal saw support arm 15 is swingably provided on a support shaft 14 extending from the head 11, and a metal saw 16 (see FIG. 2) is rotatably provided at the other end of the metal saw support arm 15.

The metal saw 16 is rotationally driven together with the chuck 13 by a motor for driving the chuck 13 through a rotation shaft provided by penetrating the gear train in the metal saw support arm and the support shaft 14. It has become.

A disk-shaped cam 17 having a notch 18 at the same center as the center of the support shaft 14 is attached to the side surface of the metal saw support arm 15, and the frame 10 is supported.
A pressing means 19 capable of pressing the notch 18 of the disk-shaped cam 17 is provided on the.

As shown in the sectional view of FIG. 2, the pressing means 19 engages with the notch 18 of the disc-shaped cam 17 and can press it, and has a rod-shaped pressing member 20 having a flange 20a at the bottom thereof. A bush 21 for guiding the pressing member 20 so as to be slidable up and down, and a spring 2 for urging the pressing member 20 upward.
2 and a spring receiver 23 having a hexagonal hole for receiving the lower end of the spring are arranged in a hole 24 formed in the frame 10.
The bush 21 and the spring receiver 23 are screwed into the hole 24.

The position of the notch 18 of the disc-shaped cam 17 is such that the pressing force of the pressing member 20 can be received even when the metal saw 16 cuts the work piece 12 having the smallest diameter. In addition, the disc-shaped cam 17 of the pressing member 20.
It is preferable that the tip contacting with is rounded or rounded.

The operation of this embodiment thus constructed will be described with reference to FIGS. First, when cutting a work piece, the disc-shaped cam 17 presses the notch 18 upward by a spring 22 with the metal saw 16 in contact with the work piece 12 as shown in FIG. It is pressed by the member 20. As a result, the metal saw support arm 15 is urged to rotate in the direction of arrow A (counterclockwise) around the center O of the support shaft 14, and in addition to its own weight, the work piece 1
2 will be pressed.

The pressing force of the metal saw 16 against the workpiece 12 is adjusted by rotating the spring receiver 23 screwed into the hole 24 of the pressing means 19 and moving the spring support 23 up and down. This can be done by adjusting the biasing force on. Further, if the position of the spring receiver 23 is kept constant, the compression of the spring 22 by the disc-shaped cam 17 increases as the diameter of the workpiece 12 increases, so the pressing force of the metal saw 16 on the workpiece 12 also increases. Become.

When the cutting (cutting) of the work piece 12 by the metal saw 16 is completed, the metal saw support arm 1 as shown in FIG.
The workpiece 5 is rotated from the workpiece 12 in the direction of arrow B (clockwise) to be retracted, and is made to stand by for the next work. In this case, the pressing member 20 is pressed by the notch 18 of the disk-shaped cam 17 and descends, and finally comes out of the notch 18 and comes into contact with the outer peripheral portion of the cam to be in the state as shown in the figure. In this state, the pressing member 20 does not give a rotational force to the disc-shaped cam 17 but merely acts as a brake, so that the position can be maintained even if the metal saw support arm 15 is stopped at any position.

[0019]

According to the present invention, in a pipe cutting machine in which a metal saw is driven by a motor for driving a chuck, it is possible to eliminate the insufficient pressing force of the metal saw when cutting a work piece of a light metal saw support arm. Become.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention.

FIG. 2 is a sectional view showing a main part of an embodiment of the present invention.

FIG. 3 is a diagram for explaining the operation of the embodiment of the present invention.

FIG. 4 is a view showing a conventional portable pipe cutting machine.

[Explanation of symbols]

10 ... Frame 11 ... Head 12 ... Workpiece material 13 ... Chuck 14 ... Support shaft 15 ... Metal saw support arm 16 ... Metal saw 17 ... Disc-shaped cam 18 ... Notch 19 ... Pressing means 20 ... Pressing member 21 ... Bush 22 ... Spring 23 ... Spring holder 24 ... hole

Front page continuation (58) Fields surveyed (Int.Cl. ⁷ , DB name) B23D 21/00 520

Claims (2)

(57) [Claims] 1. A frame, a chuck that is attached to a horizontal rotation shaft provided in a head portion of the frame and holds a workpiece, and a metal saw that cuts the workpiece held by the chuck. A pipe cutting machine comprising: a metal saw supporting arm that supports the metal saw and is pivotally supported at a position away from a central axis of the metal saw; and a motor that rotates the chuck and the metal saw. A disc-shaped cam having a notch in a part of its outer periphery is fixed to the metal saw support arm such that its center coincides with the center of the support shaft of the metal saw support arm, and the cam is attached to the frame. A press member that can be engaged with and disengaged from the notch of the cam and a spring that urges the press member are provided, and the press member has a notch of the cam at the position where the metal saw cuts the workpiece. The metal saw is pressed against the work material by engaging with the portion, and when not cutting, the pressing member escapes from the notch of the cam to release the pressure of the metal saw on the work material. A pipe cutting machine. 2. The pipe cutting machine according to claim 1, further comprising means for adjusting an urging force of a spring for urging the pressing member provided on the frame.