DE3506943A1 - Thread-cutting die - Google Patents

Abstract

The described cutting die for external thread differs from the conventional cutting dies by additional openings which are drilled at the edge of the usual chip openings (2) and into which cylindrical rams (6) of a slightly larger diameter are forced. As a result, the cutting teeth are bent in such a way that they then bite into the workpiece only in a very small, virtually punctiform region (Fig. 4). …<IMAGE>…

Description

_3_ 3505943

11700 / H / Elf

Thread cutting dies

The invention relates to a thread cutting die according to the preamble of claim 1.

Such devices (referred to as "dies" although not necessarily made of iron must), are known to be used for cutting external threads.

The invention is intended to provide a cutting die (cutting nut) for cutting an external thread the friction with respect to the processed material, especially metal, is significantly lower and the service life is much larger than with the known dies.

This object is achieved by the characterizing features of claim 1.

According to the invention, the cutting teeth (cutting prongs) of the cutting iron are inclined in this way or against the Workpiece surface tilted that they only in a very 3Q attack a small, almost punctiform area on the workpiece. In addition to a significantly longer service life and lower friction, the present die also has nor the advantage that the desired thread is cut very precisely and smoothly.

In a preferred, but not restrictive, exemplary embodiment the invention is explained in more detail below

explained. In the drawing show:

1 shows a conventional thread cutting die for comparison purposes;

Fig. 2 shows a thread cutting die on a larger scale

according to the invention in the state before a stretching process;

3 shows a section through FIG. 2 along the plane III-III; ^and

FIG. 4 shows a view of the thread cutting tool according to FIG. 2, but in the operational state.

The conventional die shown in Fig. 1, for example a hand thread cutter for coarse external threads, is known to consist of a body 1 with several openings 2 for the exit of the chips. The openings 2 surround the machining area delimited by the cutting teeth 3 on a theoretical cutting circle 4, which has a certain diameter D.

In the known die, the outer edge of the cutting teeth 3 coincides exactly with the cutting circle 4 mentioned together. It is believed that the contact between the cutting teeth and the metal of the workpiece leads to considerable wear and tear and a short tool life of the die during machining.

These problems are solved by the die described here according to FIGS. 2 to 4. This die contains in his body 1 further, additional openings 5 in the shape and position shown. The openings 5 are smaller than the openings cut by them 2. The The purpose of the additional openings 5 is to accommodate cylindrical button-like or piston-like elements 6, which have a slightly larger diameter than the openings

_ ₅ _ 3-06943

and pressed in under pressure. By the bigger one In this case, the diameter of the piston elements 6 is forced to stretch the material. This causes stretching a bending of the cutting teeth 3 according to the arrow 7 in Figure 4, so that the cutting teeth in the illustrated Way to be bent away from the cutting circle 4 while forming an angle. They describe you Arc deviating from its curvature circle. As can be seen from FIG. 4, this is a limitation of the Touching the cutting circle 4 on a point or

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a minimal area. The »center of curvature of the cutting

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teeth obviously deviate from the center of the die away.

Due to this structural deformation, the zone of friction between the cutting teeth 3 and the machined Workpiece reduced to a minimum, thereby improving the machining quality and reducing the wear and tear of the Cutting teeth 3 is reduced.

The described displacement of the cutting points can obviously only be achieved by deformation the piston elements 6 used can be achieved. The piston elements 6 are intended to be frictionally engaged in the body 1 remain and reinforce it mechanically.

The following properties and advantages of the thread cutting tool described here should be pointed out in particular:

(a) The production of the thread cutting tool only requires an additional hole in each case next to the normal openings 2 for the chips to exit. These correspond to the openings 5, the openings 2 intersecting holes form the longitudinal ones Excerpts that can be used for later stretching or stretching.

Winkolvorschiebunq the partition walls carrying the cutting teeth are necessary.

(b) The aforementioned deformation is forcibly forced by the penetration of the piston elements 6, which are larger Have diameter than the openings 5, whereby the position of the cutting teeth in the in Fig.2 and Fig.4 shown way changes.

(c) The contact of the cutting teeth with the material, in which, for example, a coarse thread is worked is therefore limited to only one point or a very small area. This will make the Wear is reduced to a minimum and consequently the cutting process is improved as well as a longer service life the cutting teeth reached.

The number and location of the additional openings 5, which interact with the conventional openings 2 for the exit of chips, can be varied within the scope of the invention. The same applies to the diameter of the additional openings, to the diameter of the button or piston-shaped deformation elements and to the angle that the cutting teeth form with the theoretical cutting circle 4, which coincides with the circumference of the processed material corresponding to the coarse thread mentioned. It is also unimportant for the invention which mechanical elements are used to manufacture the cutting tool described.
30th

Claims (2)

DR. DIETER V. BEZÖLD DIPL. ING. PETER SCHÜTZ DIPL. ING. "WOLFGANG HEUSLER MARIA-THERESIA-STRASSE 22 POST BOX 86 02 60 D-8OOO MUENCHEN 86 APPROVED BY THE EUROPEAN PATENT OFFICE EUROPEAN PATENT ATTORNEYS MANDATAIRES EN BREVETS EUROPEENS TELEPHONE 089/4 70 60 06 TELEFON 089/4 70 60 06 TELBEX 822 638 .Barcelona a Puigcerdä, Km 69,600-Poligono Mas GaIi GURB-VIC (Barqelona) / Spain - 10 thread cutting dies patent claims 1.) Thread cutting dies with provided on the cutting area Openings for the exit of the chips, between which the intermediate walls supporting the cutting teeth stand, characterized , that with the chip openings (2) in connection with further openings (5) with a smaller diameter are provided which on their inside over the length of the opening form an expandable cutout, and that in the additional openings (5) engaging piston elements (6) are provided which have a slightly larger diameter than these openings (5) and bend the partition walls supporting the cutting teeth (3) in such a way that the contact between the cutting teeth (3) with the theoretical cutting circle (4) or the circumference of the workpiece to be machined punctiform or to a minimum Area is limited. POSTSCHECK MÖNCHEN NO. 69148-800 BANK ACCOUNT HYPOBANK MÖNCHEN IBtZ 70020040) KTO. 6060267378 SWIFT HYPO DE MM 2.) thread cutting iron according to claim 1, characterized in that all cutting teeth (3) in groups due to their angular offset from the theoretical cutting circle (4) depending on the difference in the diameter of the additional openings (5) and the piston elements (6) each on one Arc lie whose radius or center from the geometric
Center of the die deviates, and that the
Piston elements (6) pressed in under pressure for mechanical reinforcement of the cutting iron remain permanently in it.