SU625824A1 - Tap for making thread by rolling - Google Patents

Description

one

The invention relates to the field of metal forming, namely, devices for rolling internal elastic threads.

A tool for making threads in nuts is known, made in the form of two stages, the first of which is a reamer, turning into an incomplete profile tap, and the second is a thread-deforming tap with a calibrating section 1.

The closest known rescue is a two-stage tap consisting of two consecutive canal-forming and thread-deforming steps with intake and calibrating sections having the same pin of protrusions and rigidly interconnected with a notch 2.

The disadvantage of these taps is that they cannot be used in the manufacture of elastic threads in the hole.

The aim of the invention is to obtain an elastic thread.

This goal is achieved by the fact that the protrusions of the thread-deforming stage are displaced along the axis of the tap by half a step relative to the protrusions on the capped stage, and the length of the pit, taking into account the length of the intake section of the thread-forming stage, is less than the length of the thread being rolled.

Such an embodiment of the tap provides for obtaining an elastic thread by converting the groove formed by the groove-forming part of the tap into the cavity when the thread is rolled by the thread-deforming part of the tap.

FIG. Figure 1 shows a tap for making elastic threads by plastic deformation; in fig. Figures 2 and 3 show the profiles of the groove-forming and thread-deforming steps.

The tap for the manufacture of an elastic thread by the method of plastic deformation contains a groove-forming step 1, which provides a screw groove of a triangular profile with a step S equal to the step 5 of the resulting thread, using the cutting method or plastic deformation. The thread-deforming step 2 is a tubeless metchk (according to GOST 18840-73), the tops of the thread profile of which are displaced along the axis of the spine jpy jj jjj j

half a step; - relatively

to a

protrusions of the canal forming stage. Stage 2 is rigidly connected with step 1 by means of a tool 3, the length of which, taking into account

the length of the intake part of step 2 does not exceed the length of the thread formed.

The production of the elastic thread by the tap is carried out as follows.

Step 1, moving in the hole of the part by the self-tamping method, forms with its protrusions 4 a helical groove of the triangular profile. Since the length of the neck 3, taking into account the length of the intake part of the mortar, does not exceed the length of the hole in the part, then at the time the thread-deforming stage 2 comes into operation, step 1 does not completely exit the hole and is like a threaded cop-head ensuring the direction of the peaks Threaded Lrofil Stage 2 is strictly between the trough, the resulting groove. After the passage of the stool 2, the screw groove of the triangular profile is converted into a cavity located in the core of the thread formed profile, the elastic properties of which depend on the size of this hollow.

The proposed tap for the manufacture of threads by plastic deformation allows to obtain an elastic thread in the hole with a more favorable distribution of the bearing load over its turns, which significantly affects the increase in strength of the entire threaded joint.

Claims (2)

1. Patent PPR number 20809, cl. 40B 29/00, 1964. 2. USSR author's certificate number 217180, .kl. In 23g 5/06, 1965.