CH253758A - Process for machining tubes and tubular articles of metal, means for carrying out this process and product obtained by this process. - Google Patents

Description

Process for machining tubes and tubular metal articles, means of mixing the work of this process and the product obtained by this process.

The present invention relates to a process for machining metal tubes and tubular articles, to a means for the. implementation of this process and to a product obtained by this process.

The product is referred to herein as a tube; these include, in particular, gun barrels, interior fittings and similar objects. The process makes it possible to obtain internal configurations of the tube, such as triel de eanons. flutes, ribs and other similar configurations.

The process is characterized by the fact that Von places the first tube ä. machining on a front mandrel on its surface the reverse of 1a. configuration to be given to the tube, and in that the tube and the mand.rin are then forced through an axis by a relative axial movement of the axis and of a member which acts at the end of the tube. tobe removed from Gelle presented pre mii-remünt to the matrix, means being provided to make the chuck free to move relative to said body to allow the lengthening of the tube which accompanies this operation.

The means for the application of this method cst. characterized by a matrix, by a diin man and by a stopper adapted to receive one end of the chuck and allows the first relative axial movement -of the chuck and the belt. The product obtained by this process is a tube, in particular a gun barrel, a

interior trim or a similar object, characterized by an interior surface machined by said process.

The adjoining ss.in represents, by way of example, a form of execution of the mayen for the implementation of the process which is the subject of the invention.

In the embodiment shown, the means comprises a die a, having the greater part of its surface formed in a configuration which is the complement of gel to be produced in the tube to be machined; This configuration being indicated by the oblique lines represented on this maudrin in the drawing. The upper end of this mandrel is introduced into a bore amena.ge in a stop b secured to a plunger c which can be given a reciprocating movement by any coainus means such as hydraulic or mechanical press. This end of the mandrel is free to slide in the abutment, and when the mandrel is intended to work with its axial axis vertically downwards, a locking mechanism is achieved. spring @ comprising balls d controlled by springs e is Jis posed dann. abutment so as to .co.operate with a gonge f cut in the first chuck, the first purpose of the lock being to maintain the marndrin temporarily in its. initial position of striation operation.

The tube g, open at both ends, is placed on the mandrel on which it is adjusted

precisely; then the upper end of the mandrel is inserted into the stopper. The upper extremity of the tute can also be nearly in contact with the lower extremity of the abutment. The diameter of the part of the goal immediately adjacent to the head is of a diameter slightly less than that of the head and such that it can pass through the die described later. In addition, the end of the stopper which makes contact with the head is preferably formed with a concave or shallow conical clearance, as shown in the drawing, so that contact with the head is close to the periphery of it to prevent its upper part from Wecrase extending below. the effect of the pressure exerted on him.

The die h is of the type generally used for operations, on the die and adapted so as to produce a slight reduction in the outside diameter of the rod, the die being mounted on any suitable stationary support. i.

When the chuck and the head have been placed in position, the plunger is lowered, the lower end of the tube then coming into contact with the die, as shown in the drawing. Continued movement of the plunger forces the tube through the die and produces compression of the tube on the mandrel resulting in a distortion of the inner surface of the complementary tube of the mandrel. During this operation, the length of the rod is increased to some extent, and as the part of the rod which has passed through the die grips the chuck tightly, there is relative axial movement between the chuck and the die. part .of tute eituee above the. matrix. This movement is made possible by the freedom of the upper part of the maadrin to move relative to the abutment. When the lock described above is used, the movement of the chuck produces its release. When the rod has been passed through the die, it is withdrawn to the lower part of the die with the mandrel, while the plunger is pulled back.

leads to its upper position, ready for the next operation on the next head.

The mandrel is then extracted from the tube, but since the tube usually closes on the mandrel after passing through the die, it is usually necessary to perform a tempering operation before pull out the 1st chuck. This tent is made by passing the chuck through a roller device or other similar machine which produces a slight expansion of the chuck and thus allows the chuck to be easily removed.

While we have deerit a device with downward vertical movement of the tute and its mandrel, one can provide, devices in which the first movement is vertical upward, or horizontal; in res variants, the locking described is not necessary. Furthermore, although it would be more practical to use a fixed die and a movable stop, this is not essential to the invention, the stop being able to be fixed and the movable die, the die then remaining stationary during 1 'operabion.

The invention is also applicable to various other uses in much the same way as discussed above. For example, it may be employed to form spirals or other grooves, longitudinal ribs, keyways, bosses or other like formations on the inside surface of tubular articles of metal, provided that 1a vonfigunation somit such that the first chuck can, e eire removed by an axial movement with or without operation of Betente -tute.

The process described is analogous to a press spinning process and differs from a drawing process in that during the relative movement of the tube and the die, the tube is subjected to axial pressure. , rette pressure being exerted by 1a. abutment on the extremity of the tobe away from Gelle presented first to the die, when a mobile abutment is used, or conversely, received by the abutment which resists it when a fixed bu tee is used. The use of this process provides many advantages over atz drawing process, rar it does not involve any waste

of any part of the spike in operation, and the total operating time required to obtain the desired result is relatively short.

Claims (1)

CLAIMS I. Machining method-@ tubes and, d'artwles tibulaires metal, including gun barrels and interior fittings, characterized by the 1st fact that Fon places the 1st hüsin-er tube on im mandrel having at its , surface the reverse of the configuration to be given to the tube, and in that the strong force then the tube and the first mandrel has passed through a m hice by a relative axial movement of the die and of a member which, i.bit on the extremit6 @ of the tube remote from that first presented in the. matrix means being provided to make the first mandrel free to move relative to said member to allow the lengthening of the tobe which ac compabgne this opkation. II. Means for 1o implementation of the pro <B>c64</B> according to claim I, characterized by a matrix, by a mandrel and by a stop ad @ adapted to receive an end of the mandrel and allow the first relative axial movement of the chuck and stop. III. Product obtained by the first process, e according to claim I, sofft a tube, a gun barrel, an interior trim or a similar object, characterized by a surface. Interior us-inee by the first process, of according to the claim I.