FR2464764A1 - Punching of blanks for mfr. of seamless tubes - indicating error of alignment by mercury bubble level - Google Patents

Abstract

The first stage in making seamless tubes consists of punching a hole in the blank. If the punch is eccentric to the blank there is a deviation in the wall thickness of the finished tube. This defect can be avoided by fitting the punch (4) with mercury bubble levels (1). A number of electrical contacts (3) is sealed in the wall of the phial (1) containing the mercury. If the punch is not correctly aligned with the blank, the variation of the number of contacts (3) that are immersed in mercury generates a signal which indicates the error in alignment.

Description

 The present invention relates to a device for automatically indicating eccentric punching in punching presses.

At the first stage of the manufacture of seamless tubes, during punching with the press, it can occur, as a result of an eccentric application of the punch and an oblique movement during punching, defects which can no longer be compensated in the rest of the manufacturing process. If the punch moves obliquely, the wall thickness at the lower end of the hollow ingot becomes, for example, non-uniform and these defects are found in the finished tube.

Exactly centered application of the punch can be ensured by concrete measures of compulsory guidance.

However, this device cannot pocket the punch to deviate to the side in the material during the punching process, so that an eccentric hollow ingot is obtained. From the operation of the installation, it cannot be known whether, in a specific punching process, the punch has deflected or not. If we were able to detect immediately after the punching an oblique movement of the punch, it is true that we could no longer correct the punched ingot, but we could then eliminate an eccentric punching by carefully adjusting the instaXlation or other measurements.

 The object of the invention is to provide a device which indicates eccentric punching in a punch press and which thus makes it possible to avoid the production of new eccentric ingots.

 To solve this problem, the invention relates to a device characterized in that in the punch are installed two level bodies filled with mercury, placed at 900 one from the other and provided with sealed contacts connected to an indicator.

Thanks to the device according to the invention, it is possible to monitor the quality during production since it is possible to eliminate the defective ingots immediately after the punching and to avoid a new eccentric punching by checking the new settings of the press.

A possible embodiment of a device according to the invention is shown schematically by the accompanying drawings in which
Figure 1 shows a punch with levels incorporated, and
Figure 2 is a section of a level.

Figure 1 shows the arrangement of two levels in a punch 4. As shown in Figure 2, these levels are formed by a level 1 body filled with mercury 2 and in which are sealed several contacts 3 leading to an indicator (not represented).

 In a punch equipped according to the invention, the angular position of the levels relative to the horizontal is indicated in each case by the contact which is inside the air bubble and which, thus, is not in conductive connection with the contained mercury. Appropriate and generally known electrical measuring instruments can then, according to the two levels placed at 900 from one another, determine and indicate both the direction and the angle of a possible deviation of the punch.

Claims (1)

 CLAIM Device for automatically indicating an eccentric punching in punching presses, characterized in that in punch 4 are installed two level 1 bodies filled with mercury 2, placed 900 from each other and provided with contacts seals 3 connected to an indicator.