FR2482481A1 - METHOD FOR CONTROLLING A PNEUMATIC DRIVE PUSHER USED IN A NON-PILGRIM ROLLING SYSTEM AND DEVICE FOR CARRYING OUT SAID METHOD - Google Patents

Abstract

THE INVENTION RELATES TO A PROCESS FOR CONTROLLING A PNEUMATIC-DRIVEN PUSH USED IN A PILGRIM STEP LAMINATION PLANT. THE PROCESS CONSISTS OF VARIING THE VOLUME OF THE AIR ACTING ON THE PNEUMATIC PISTON 6 AS A FUNCTION OF THE TIME AND OR AS A FUNCTION OF THE POSITION OF THE PUSHER. APPLICATION IN PARTICULAR TO PILGRIM STEP ROLLING MILLS FOR TUBE ROUGHING.

Description

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  The present invention relates to a method for controlling a pneumatically driven pusher used in a pilgrim rolling plant and to

  a device for implementing this method.

  It is known that the rolling capacity of a pilgrim rolling train is determined, inter alia,

  by the working capacity of the pusher.

  If the power of the drive motor of the rolling mill is sufficient, the maximum speed of the rolling mill depends on

  directly from the speed of the stuffing.

  The stuffing work is provided by compressed air. The compression of air occurs during the working run of the rolling mill and is ensured by the drive motor, thanks to the adhesion between the rolls and the rolled metal and the depression

  pneumatic piston in the compression chamber.

  The compression process is therefore a function of the

pneumatic piston stroke.

  During the recoil stroke of the pneumatic piston,

  the pressure increases in the compression chamber.

  At the end of a deformation stroke, the pilgrim cylinder is detached from the rolled metal and the compressed air provides braking and then a return movement of the pneumatic piston, the mandrel and the hollow ingot to the cage

of the rolling mill.

  This pushing operation is again stopped by a brake and can then trigger a new

deformation race.

  This process has disadvantages in a number of ways. During the deformation stroke, that is to say during the recoil of the pneumatic piston, it may occur that, due to a too strong back pressure exerted by the compressed air, the bonding connection between the cylinders and the tube breaks in the polishing portion or in the region of the exit of the flute of the pilgrim cylinder and that the tube is pushed back into the groove. This may result in damage to the tube surface, a lack of accuracy in the length of the 2- return stroke and, in the case of rotating mills

  automatic, a de-precision defect of the angle of rotation.

  Therefore, the compression pressure can not be raised to any desired value and the result is that the time required for reversing the direction of motion and for pushing is too long, especially in the case where

  the masses to put in motion are large.

  The object of the invention is to provide a method and a device for controlling the pusher used in a pilgrim rolling plant, with the aid of which

  we can obtain an acceleration of the operation of pus-

  wise and, as a result, an increase in productivity

rolling.

  According to the invention, this problem is solved by the fact that, in such a method, the volume of the air acting on the pneumatic piston is varied as a function of time and / or according to the movement of the pusher and, according to the invention,

  another aspect of the invention, it is resolved by a

  positive for the implementation of this method applied to a pilgerin lamination installation comprising a pneumatic piston integral with the pusher and which moves in a compression chamber under a pneumatic action, this device being characterized in that it comprises a second chamber which communicates with the compression chamber via a conduit and in which slides a piston driven by a

crank mechanism.

  The advantages of the solution according to the invention reside in a strong initial acceleration of the parts set in motion at the moment of reversal of the direction of movement at the rear dead center of the pneumatic piston. The

  phase shift makes it possible to better adapt the course of the

  pneumatic piston to the characteristics of the lami-

  swimming. An embodiment of the invention will be described below by way of nonlimiting example with reference to the accompanying drawings, in which; Figures 1a, 1b and 1c show a pneumatic piston pusher mechanism in its rest position; Figures 2a, 2b and 2c show a pneumatic piston pusher mechanism at the end of the working stroke. Figures 1a, 1b and 1c show the assembly of the compression chamber, which is composed of the compression chamber of the piston pump 1, the pipe 3 and the - the compression chamber of the body 4 of the pusher. In FIG. 1a, the piston 5 of the piston pump 1 is in the central position, in FIG. 1b it is in position

  final and, in Figure lc, in the starting position.

  In the various figures, the set of compression chambers (indicated by hatching) has different volumes, the largest volume being in the position of Figure 1c, an average volume in the position of Figure la and the most small volume in the position of Figure lb. In Figures 2a, 2b and 2c, the pneumatic piston is shown at the end of its working stroke. Here also, the figures show different positions of the piston 5 of the pump. Figure 2a shows the central position, Figure 2b the final position and Figure 2c the starting position. Compared to the position of the pneumatic piston 6 which is shown in Figs. 1a, 1b, and 1c, the total volume is reduced by a value equal to the displacement of the pneumatic piston. If the piston 5 remains constantly in its central position, which is represented in FIGS. 1a and 2a, the variation of the volume and of the compression pressure depends solely on the variation of position of the pneumatic piston.

  6, as happens in the usual technique until

  than now. With the method and the device according to the invention, which use the piston pump 1, it is possible to obtain an additional modification of the volume and of the pressure during the displacement of the pneumatic piston. This change may consist of an increase or a

  decrease in pressure or volume.

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  The phase shift cycles created in accordance with the invention make it possible to judiciously modify the

  curve of variation of the pressure during

  this pressure, in particular by modifying the

study of variation.

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Claims (5)

  1. A method for controlling a pneumatically powered pusher used in a pilgering plant, characterized in that the volume of the air acting on the pneumatic piston is varied by   function of time and / or movement of the pusher.   2. A process according to claim 1, characterized in that, in a movement cycle, the volume of the air undergoes a volume variation determined in advance, the movement cycle being related to the movement cycle of the pneumatic piston. by a report which is expressed by a whole number.   3. Process according to one of claims 1 and 2,   characterized in that the two cycles of movements are phase.   4.- Device for implementing the method   according to one of claims 1 to 3, applied to a   pilgering machine comprising a pneumatic piston integral with the pusher and which moves under a pneumatic action in a compression chamber, this device being characterized in that it comprises a   additional room (1) connected to the room of compres-   (4) by a duct and in which slides a   piston (5) driven by a crank mechanism (2).   5.- Device according to claim 4, characterized in that the piston (5) is driven in phase shift   relative to that of the pneumatic piston (6).