JPH1199414A - Tap - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a tap which uses deformation of a raw material. SOLUTION: This tap is formed into an idle shape, and involves an annular thread 15 and a body 3 for supporting three rotating cylinders 4, 5, 6 separated according to the value of a pitch of threads to be formed. The three cylinders are disposed regularly and inclined axially by an angle equal to the helix angle of the thread to be formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a tap,
It is generally a metal, but any other material, but relates to a tool that forms threads inside a hole in a preformed circular cylindrical portion.

[0002]

BACKGROUND OF THE INVENTION In its broadest form, taps whose peripheral surface is threaded in a shut-off manner are tools, which are made by removing material and, more particularly, by removing chips. Defines the working cutter.

[0003] A tapping method for removing chips is as follows.
It has disadvantages attributed to its basic design. Chip removal results in cutting the metal fiber, often resulting in inadequate thread resistance.

[0004] This is why other forms of taps are currently preferred and are acted upon by deformation of the material and therefore do not prohibit metal damage.

[0005] Such a tap is a tap having a polygonal cross section. When the tap enters while rotating in the hole to be tapped, it is the top of the polygon that deforms the material to form the desired thread.

The step of tapping by deformation is now considered as the only step that is effective in obtaining a high resistance and reliable long life thread.

[0007] Deformation taps currently known, ie, taps of polygonal cross section, have a large frictional force caused by a considerable acting force which is necessarily exerted when they act to deform the material. Easy to receive. This results in considerable heat and wear of the taps, and therefore a relatively short life.

In addition, the speed of the work of these taps is
Naturally, they are relatively slow, and these taps can be applied to the same applicant in European Patent Application (EP-A) 0192586.
It penalizes industrial productivity when prepared as an automatic tapping device, as indicated in the article.

[0009]

SUMMARY OF THE INVENTION It is an object of the present invention to overcome the disadvantages of deformation acting taps as currently used in the prior art.

[0010]

SUMMARY OF THE INVENTION Accordingly, the present invention is directed to a tap for forming a helical thread having a smooth wall and a uniform circular portion within a hole by deforming the material. The tap has a rigid body, a radial dimension smaller than the diameter of the hole to be tapped, and a rigid body for holding a plurality of relatively small circumferential rotating cylinders of the same diameter. The rotating cylinders are regularly spaced apart and are provided in idle in respective receiving recesses of the circumference of the rigid body and are supported by each two shaft ends, these rotating cylinders comprising:
Provided with sharp annular threads, these threads are therefore completely circular, not spiral, and are spaced apart from each other by a distance equal to the pitch at which the threads are to be formed, Are coaxial and have a common axis inclined by an angle equal to the torsion angle of the thread to be formed with respect to the axis of the tap, each cylinder being coaxial with the bore to be tapped. A rigid body,
Protruding sufficiently from the circumferential surface of the rigid body to fill the annular space present between the threads to be formed, the cylinders are provided with their respective two shaft ends adjusted. Except all being equal, the first annular or leading thread of the second cylinder is axially offset in relation to that of the first or leading cylinder, and the offset is: The proportion of the pitch equal to the number of cylinders, i.e., if the tap has cylinders such as N, the "Nth" proportion of the pitch,
The last from the cylinder to the following cylinder is the last, that is, the Nth.

The end of the first annular thread of each cylinder is:
Advantageously spaced from the cylinder axis less than necessary to form the desired thread, the end or leading thread of the first annular thread ensures centering of the hole to be tapped. To be sufficiently spaced from this axis so that successive threads, or threads, are progressively increased until one reaches the end, which is necessary to effectively create said threads. From each other.

[0012]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.
Shows a tap with a solid metal cylindrical rod 1. One free end 2 of this cylinder 1 is formed as an endpiece having a square cross section, and the other free end is enlarged so as to form a rigid cylinder body 3 having a cylindrical cross section. The diameter of the rigid cylinder 3 is, for example, two to three times larger than the diameter of the cylindrical rod 1.

This diameter is about 25 millimeters in this embodiment. In any case, this is only about 1-2 millimeters smaller than the diameter of the hole to be tapped.

The rigid cylinders 3 are regularly arranged on the peripheral surface of the main body 3, and each receiving recess 7 formed on the peripheral surface of the main body 3.
And a relatively small circumferential metal rotary cylinder 4, 5, 6 provided in an idle state.

The diameter 8, 9 at the free end of each cylinder is adapted to rotate freely with light friction in the complementary receiving recess 7,
The diameter is reduced to form two axes.

Each of the rotary cylinders 4, 5, and 6 has a screw 12,
Annular ring 10 fixed to body 3 by 13 and 14
And the cover 11 are detachably held in the receiving recesses 7.

The three cylinders 4, 5, 6 are the same. The only difference is that the lengths of their shaft ends 8, 9 are different in order to give them a longitudinal deviation, as will be seen from the description below.

As is evident from FIG. 3, each rotary cylinder is provided with a sharp thread 15 which is annular and not as helical as possible. These perfectly circular threads are axially separated from each other by a distance equal to the pitch d at which the threads are to be formed.

The common axes 16 are inclined at an angle a (FIGS. 1 and 3) with respect to the axis 17 of the tap,
This is equal to the helix angle of the thread to be formed.

The shaft ends 8 and 9 of each of the rotating cylinders 4, 5, and 6 have a threaded portion of each of the cylinders 4, 5, and 6 on the peripheral surface of the main body 3 from one cylinder to the next. The pitch is adjusted to be twice as large.

In other words, the first annular thread 151 of the second cylinder 6 (FIG. 1) is axially offset by three times the pitch of the first cylinder 4, and The third cylinder 5 is also applied to the second cylinder 6.

In addition, the diameter of the circle formed by the first end 151, 152, 153 of each cylinder, ie the leading edge, allows for the centering and in turn the start of sufficient tapping for that tap. The diameter is effectively increased until the required diameter is at the fourth end 154.

As apparent from FIG. 2, the cylinder 4,
5 and 6 project sufficiently from the peripheral surface of the cylindrical body 3 to fill the tubular space existing between the bodies 3, which comprises holes to be tapped and screws to be formed. When the tap finally enters the hole while rotating, the thread is formed at a desired pitch d and a twist angle a by deforming the material by c4, 5, and 6. Is done.

It goes without saying that the present invention is not limited to the embodiment described above. For example, cylinder 4,
5 and 6 may be held on the main body 3 by means other than the annular ring 10 and the cover 11. Further, the number of rotating cylinders may be more than three. However, preferably there are at least three.

[0025]

According to the present invention, by deforming the material,
A helical thread with a smooth wall and a uniform circular portion can be formed inside the hole.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional overall view of a tap according to the present invention using material deformation.

FIG. 2 is a view showing a state in which a bottom cover is removed from a direction F in FIG. 1;

FIG. 3 is a view showing one of three working cylinders mounted on the tap of FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... cr 3 ... Solid cylinder (shape) (main body) 4, 5, 6 ... Metal rotary cylinder 7 ... Reception recess 8, 9 ... Shaft end 10 ... Annular ring 11 ... Cover 15 , 151 ... (circular) thread

Claims (3)

[Claims] 1. A tap for deforming a material to form a helical thread having a smooth wall and a uniform circular portion inside a hole, the tap having a radial dimension. It has a rigid body (3) for holding a plurality of circumferentially rotating cylinders (4, 5, 6) of the same diameter, which are smaller than the diameter of the bore and which are relatively small, said rotating cylinders Spaced apart in each receiving recess (7) of the circumference of the rigid body (3), and each of the two shaft ends (8,
9), each of these rotary cylinders is provided with sharp annular threads (15), these threads are therefore not circular but full circular, and the threads are Spaced apart from each other by a distance equal to the pitch (d) to be formed, said annular thread (15) being coaxial and having an angle (a) equal to the torsion angle of the thread to be formed with respect to the axis of the tap. Each cylinder having a common axis which is only inclined to fill the annular space existing between the rigid body provided coaxially with the hole to be tapped and the thread to be formed. Because the rotating cylinders (4, 5, 6) are all equal except for their respective two shaft ends (8, 9), The second cylinder (6 ), The first annular or leading thread (151) is axially offset in relation to that of the first cylinder (4) or the leading cylinder, the offset being the number of cylinders. That is, if the tap has N or other cylinders, then the "Nth" percentage of the pitch, from a cylinder (6) to the following (5), at the end, or up to the Nth A tap used to transform a material characterized by. 2. The first annular thread (15) of each cylinder.
1, 152, 153) are spaced from the cylinder axis less than necessary to form the desired thread, and the end of the first annular thread (151), the leading screw. The threads are spaced sufficiently from this axis to ensure the centering of the hole to be tapped and the subsequent threads or threads (152, 15)
3, 154) are each spaced from this axis (16) such that one necessary to create the thread effectively increases in sequence until finally reached. A tap used to deform the material described in 1. 3. At least three rotating cylinders (4,
The tap used for deforming the material according to claim 1, wherein the tap has the following features: