JPH0118242Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a pipe cutter that is attached to the outer circumference of a pipe to cut, groove or chamfer the pipe.

The present invention aims to provide a pipe cutter with a simple structure that uses a cutting tool as a cutting tool in order to obtain a clean right-angled cutting surface.

Cutting with a grindstone, cutting with a roller blade, etc., which have been commonly used in the past, can burn the plastic and give off a bad odor when cutting plastic-lined steel pipes, which are often used recently. It had some drawbacks, such as a large collar. Furthermore, it could not be practically applied when cutting thick-walled pipes. In order to improve these problems, the applicant of the present application previously proposed a pipe cutter with a simple structure using a cutting tool as a cutting tool (Utility Model Application Publication No. 55-60918).

However, in the pipe cutter disclosed in Japanese Utility Model Application Publication No. 55-60918, the cutting of the cutting tool is carried out by turning the handle by hand, and therefore the problem arises that the amount of cutting cannot be determined unambiguously. In other words, the more the handle is turned, the deeper the bite of the tool becomes.In other words, the amount of feed of the tool directly corresponds to the rotational operation of the handle, so the amount of biting increases each time the handle is operated. In practice, it was almost impossible to keep the value constant as it decreased.

In order to eliminate these drawbacks, the present invention provides a clutch in the handle that allows the handle to spin freely when cutting resistance of more than a predetermined value is applied to the tool, thereby virtually always keeping the cutting depth of the tool constant at one time. It is an object of the present invention to provide a pipe cutter which has been improved so as to obtain the desired results.

Explaining below with reference to the drawings, a pair of support arms 7A, 7B are attached to a pair of parallel guide rods 3A, 3B constituting a guide member. Both support arms 7
A and 7B can be relatively approached or separated as will be described later. In the illustrated embodiment, the support arm 7B is fixed to one end of the guide rod 3B, and the other support arm 7A is movable along both guide rods. Support arms 7A, 7B
has holes 9 for the guide rods 3A and 3B to pass through.
A, 9B and 13A, 13B are formed, respectively.

A hollow sleeve-shaped adjustment knob 12 having an internal threaded hole 10 is rotatably inserted into the hole 9B, and one end of the guide rod 3A is screwed into the internal threaded portion 10 of the hollow bore of the adjustment knob 12. Therefore, an outer diameter thread 14 is formed at one end of the guide rod 3A.
Further, a ring member 16 is integrally fixed to the tip of the adjustment knob 12. Therefore, the upper part of the support arm 7B is held between the shoulder portion 18 of the adjustment knob 12 and the ring member 16 so as to be able to slide relative to each other without any gap. With the above configuration, when the adjustment knob 12 is rotated, the support arm 7B is moved to the guide rod 3A.
The top is caused to reciprocate in the axial direction relative to this.

A positioning knob 20 is provided at the upper end of the support arm 7A, and a positioning pin 22 is attached to the positioning knob 20.
is fixed. The positioning knob 20 is slidably mounted on a hollow housing 24 that is fixed to the upper end of the support arm 7A by a fixing screw 28. A spring 26 is provided within the hollow housing 24 to constantly press the locating pin 22 and thus the knob 20 downwardly.

Positioning holes 32 are formed in the guide rod 3A according to the outer diameter of the pipe 50 to be cut.
The lower end of the positioning pin 22 is thrust into and locked. By pulling the knob 20 upward against the spring 26 and extracting the pin 22 from the hole 32, the support arm 7A can be slid with respect to the guide rods 3A, 3B. Reference numeral 19 denotes a mounting arm used when the cutter of the present invention is attached to a suitable cutting machine body, for example, and is attached to the cutting machine body (not shown) by passing a pin (not shown) through the hole 21, for example. Therefore, when the pipe cutter is mounted on a pipe and operated independently, the mounting arm 19 is not necessary.

Rotary support rollers 21A, 21B constituting a pipe holding device are rotatably attached to the lower end of each support arm 7A, 7B. In addition, the rollers 21C, 21
C is for holding the pipe 50 instead of the roller 21A when the pipe is of small diameter.

Further, a tool holder 34 is provided at the lower part of the support arm 7B. The tool holder 34 has a main body 36 (FIG. 2) that is fixedly held on the support arm 7B.
A sliding body 3 has a cutting tool 40 removably attached therein.
7 is slidably attached. The cutting tool 40 is removed, for example, by inserting the cutting tool into a corresponding groove 45 formed in the sliding body 37, and then pressing the shank portion of the cutting tool with the tip of a screw 47 screwed into the upper surface of the holding plate 46. Ru. The sliding body 37 has a female screw hole 39 and a feed screw rod 35 is inserted into the female screw hole 39.
is screwed through the end plate 42 from the outside.

Conventionally, in Utility Model Application Publication No. 55-60918,
A knob is fixed directly to the outer end of the feed screw rod 35, and by turning the screw rod 35 with the knob, the sliding body 37, and thus the cutting tool 40, can be independently moved back and forth in the radial direction of the pipe 50. was. Therefore, as mentioned at the beginning, the cutting depth of the cutting tool 40 increases as the knob is turned, so the cutting depth changes each time the knob is turned and is not constant. This is because each operator adjusts the amount by which the knob is turned as appropriate based on his or her senses. Therefore, the present invention solves this problem by providing a mechanism that allows the cutting tool to advance only a certain amount no matter how much the knob (handle) is turned.

According to the present invention, a rod 53 (this rod is not necessarily required) is integrally fixed to the outer end of the threaded rod 35, and a handle (knob) 38 is attached to the outer end of the rod 53 so as to be relatively rotatable. . When attaching the handle 38 to the rod 53, the bolt 59 may be inserted into the rod 53 through the washer 57 into the recess 55 of the handle 38. Therefore, the handle 38 can slide and rotate at the interface with the washer 57. The handle 38 is provided with through holes 67, for example, at two or more diametrically opposed locations. A ball 63 and a spring 65, which constitute the movable clutch element of the present invention, are disposed within these through holes 67. The outer end of the hole 67 is formed as a screw hole 68, into which a machine screw (stopper) 69 for locking the spring 65 is screwed. A clutch member 61 having a V-groove 71 at a position facing the handle 38 is fixed to the rod 53. The clutch member 61 having the V groove 71 constitutes a stationary clutch element, and together with the movable clutch constitutes a clutch consisting of a pair of clutch elements that are slidable relative to each other. V groove 7
A part of the ball 63 has entered into the ball 1. That is, the ball 63 is constantly pressed against the V-groove 71 by the spring 65. Therefore, unless a load (cutting resistance) exceeding a predetermined value is applied to the rod 53 side, the rotation of the handle 38 is transmitted to the clutch member 61 via the clutch constituted by the ball 63 and the V-groove 71. That is, in this case, by turning the handle 38, the cutting tool 40 is inserted through the feed screw rod 35.
can be sent in the radial direction. On the contrary, Rod 5
When a large load is applied to the clutch member 61, even if the handle 38 is turned, the handle 38 will not close to the clutch member 61.
It just spins around the top. That is, the ball 63 ends up riding on the V-groove 71. The cutting resistance value at which the handle 38 begins to rotate idly can be arbitrarily set by the spring load of the spring 65.

By configuring as described above, the handle 38
When the feed rate of the cutting tool 40 is increased by turning the , the cutting resistance increases accordingly, so the resistance force acting on the clutch member 61 side also increases.
The handle 38 will now spin idly. Therefore, according to the present invention, even if the handle 38 is turned casually and largely, if the cutting resistance of the cutting tool exceeds a predetermined value, the handle 38 will rotate idly, so that the feed amount (cutting amount) of the cutting tool will always be constant.

In particular, as shown in FIG.
In the case of a material whose cutting resistance changes during cutting, such as the pipe 50 made of 0B, the spring load of the spring 65 is determined based on the cutting resistance of the steel pipe section 50B, so when cutting the resin section 50A, the cutting resistance changes. It is much smaller, so the handle 38 may not spin freely even when turned a large amount at once. That is, when cutting moves from the steel pipe section 50B to the resin 50A, a large amount may be cut at once depending on how the handle 38 is turned. To prevent this, a notch mechanism 70 is preferably provided on the feed screw rod 35. This notch mechanism is activated when cutting resistance becomes small, and four V-grooves 36 are formed, for example, at 90° intervals on the outer periphery of the boss portion 35A of the feed screw rod 35, and one Two balls 81 are pressed against each other. The ball 81 is disposed together with the spring 75 in a blind hole 77 of the support 70 which is rotatably mounted relative to the feed screw rod 35. Support 70 is secured to end plate 42 .
Therefore, each time the handle 38 is turned by 90 degrees, that is, each time the feed screw rod 35 is turned by 90 degrees, the ball 81 snaps into the V-groove 36, and the operator can feel this in his or her hands. In this way, the operator can turn the handle in 90° increments even in the dark or by feel of the handle without having to look at it at a glance, and will not turn the handle too much. That is, sending too many bytes is avoided. By increasing the number of V-grooves 36, it is possible to control the feeding of the cutting tool in more detailed manner.

The pipe cutter constructed as described above can be attached to the pipe 50 in the following manner. First, turn the knob 12 to bring the support arm 7B to the right end position. At this time, the cutting tool 40 is in the retracted position. Next, a pipe cutter is attached onto the pipe 50.
In advance, the position of the hole 32 of the guide rod 3A is determined according to the standard outer diameter of the pipe 50.

Pull up the knob 20 to remove the pin 22 from the hole 32, move the support arm 7A along the guide rods 3A, 3B, engage the pin 22 in the hole 32 corresponding to the pipe 50, and set the support arm 7A.

Thereafter, the knob 12 is turned in the opposite direction to that described above to bring the support arm 7B closer to the support arm 7A, and the pipe 50 is securely tightened by the four support rollers 21A and 21B.

Finally, turn the handle 38 to bring the cutting edge of the cutting tool 40 into contact with the outer periphery of the pipe 50, and then
0 may be rotationally driven by a drive device (not shown). The cutting tool 40 is advanced in the radial direction by continuously turning the handle 38 according to the inner thickness of the pipe 50 until cutting is completed.

At this time, according to the present invention, the feed amount of the cutting tool is kept constant as described above.

Since it is sufficient to hold the pipe 50 at at least three locations on the outer circumference, it is also possible to replace the two rotating support rollers on one of the support arms 7A, 7B with a single roller. In that case, the single roller must be placed in a central position between the two rollers shown.

Further, the clutch means is not limited to the mechanism shown in the drawings; for example, the facing surfaces of the handle 38 and the clutch member 61 may be formed into complementary wave shapes, or friction members may be attached.

It goes without saying that the V-grooves 36 and 71 may have a circular arc groove or other shapes.

According to the present invention, since a cutting tool can be used as a cutting tool, a well-finished cut surface can be obtained at right angles to the pipe axis.

Furthermore, according to the present invention, the cutting feed amount of the cutting tool is always kept constant, so chipping and wear of the cutting tool can be reduced.

It goes without saying that by changing the shape of the cutting tool, it is possible to perform not only cutting but also cutting such as grooving or chamfering.

[Brief explanation of the drawing]

Fig. 1 is a partially sectional front view of a pipe cutter according to the present invention, Fig. 2 is an enlarged partial sectional view of the main part of Fig. 1, Fig. 3 is a plan sectional view of the main part of Fig. 2, and Fig. 4 is a partial sectional view of the main part of Fig. 2. - line end view of Figure 2; 3A, 3B... Guide rod, 7A, 7B... Support arm, 21A, 21B... Rotating support roller, 38...
...Handle, 40...Bite, 50...Pipe to be cut, 63...Ball, 65...Spring, 71...
V groove, 61...Clutch member.

Claims (1)

[Scope of utility model registration request] A pair of support arms mounted on the guide member so as to be able to approach and separate from each other are provided with pipe holding devices equipped with rotating support rollers, and at least three points on the outer periphery of the pipe to be cut are placed between the two pipe holding devices. A sliding body capable of holding a cutting tool and having a cutting tool fixed thereon is attached to at least one side of the pipe holding device so as to be movable in the radial direction of the pipe to be cut, and a feed screw shaft with a handle is screwed onto the sliding body, In a pipe cutter in which the sliding body and the cutting tool can be moved in a predetermined direction by turning the feed screw shaft using a lever handle, the handle and the feed screw shaft are configured as separate parts, and a fixed side clutch is attached to the feed screw shaft side. In addition, a movable clutch element is provided on the handle side to connect both clutch elements so that they can rotate relative to each other, and both clutch elements rotate the handle only when the cutting resistance acting on the feed screw shaft side is less than a predetermined value. is transmitted to the feed screw shaft, and when the cutting resistance exceeds a predetermined value, relative sliding rotation occurs between the handle and the feed screw shaft.