FR2744110A1 - System to control winding and unwinding of wire for electrical discharge forming machines - Google Patents

Abstract

System with control of unwinding of wire for electrical discharge forming machines comprises: (a) a wire-bg reel (3) rotating on a spindle (4) connected at one end to a driving plate (5) and having at the other end a slidable fixing cone, positioned against the reel and attachable to the spindle; (b) a storage regulating device (11) consisting of some fixed pulleys (P2, P3) and some pulleys (P4, P5) connected to a swinging arm (13), over which the wire passes before entering the working zone (t); and (c) a swinging arm position sensor (14) e.g. a photoelectric cell, which supplies information to a programmed microprocessor ( mu p) which controls the driving plate's motor (m).

Description

"THREAD REWINDING CONTROL SYSTEM FOR

ELECTROEROSION MACHINE "

  It is well known that when using EDM machines, it is necessary to control the unwinding or unwinding of the wire in order to avoid breaks, intertwining or tangling in the various loops, which may occur due to the variability of the tensions

exerted on said wire.

  Various systems are also known which make it possible to ensure such control of the unwinding of the wire. However, these systems have the drawback of being complex and therefore difficult to maintain and relatively expensive; moreover, these systems are not very versatile and do not allow the use of spools of wire of different sizes. All these problems are solved by the present invention, which consists of a wire unwinding control system for EDM machines, characterized in that it comprises: a) a wire-carrying coil rotating on an axis, one of which of the ends is detachably fixed to a drive plate and the other end of which has a sliding fixing cone, capable of being fixed on said axis, pressing against the spool, the spool thread being sent to b) a buffer device with a regulation system, composed of fixed pulleys and pulleys integral with a rocking arm, around which the wire passes successively before arriving in the work area; - 2 - c) a tilt arm position sensor, which transmits the information it collects to a microprocessor programmed to control a motor

  operating the drive plate.

  To better understand the object of the present invention, there is shown in the accompanying drawings, a preferred embodiment, which may be subject to incidental modifications.

in no way modifying the foundation.

  Figure 1 is a side sectional view, schematic, of an embodiment of the

system according to the invention.

  Figure 2 is a front view of the mode of

realization of figure 1.

  The wire (h) to be used in the EDM machine comes from the rotating coil (3)

on the axis (4).

  There is a motor (m) with its reducer (r), which activates a plate

  drive (5) rotating on a fixed support (6).

  The drive plate (5) has a blind orifice (b) threaded and pins

drive (7).

  To load the reel (3) into the machine, simply slide it onto a fixed loading ramp (8), after which it is automatically housed on two idler rollers (91), (92) arranged symmetrically with respect to the 'axis (e) of the drive plate (5). The coil (3) is then positioned coaxially with respect to said drive plate (5) and the drive pins (7) are housed in the corresponding recesses, formed on the cheeks of the coil (3). The axis (4) which penetrates into the axial bearings (o) of the coil (3), which have on their outer face frustoconical surfaces (s), has a threaded end (10) intended to be screwed into the blind hole (b) of the drive plate (5). At the other end of said axis, a fixing cone (1) threaded at (a), acting as a nut on the axis (4), engages in the corresponding frustoconical surface (s) of the coil ( 3), thus making it possible to adjust the position of

said coil (3).

  The axis (4) has along its length sections of different sizes, which allows, thanks to the different frusto-conical surfaces (s), to use coils (3) of different sizes, which are housed between the fixing cone (1) and the surface

  corresponding frustoconical (s) of the axis (4).

  The wire (h) leaves the spool (3) towards a pulley (P1), then goes towards a buffer device (11) provided with a regulation system, composed of several upper pulleys (P2), (P3) and several lower pulleys (P4), (P5) around which the wire passes successively, forming several loops (12), thus allowing storage

of said wire (h).

  In this embodiment, the path of the wire (h) is as follows: coil (3) -> pulley (P1) -> - 4 upper pulley (P3) -> lower pulley (P5) -> upper pulley (P2) -> lower pulley (P4) ->

work area (t).

  The lower pulleys (P4), (P5) are integral with a rocking arm (13) whose positioning is sensed by a sensor (14), such as, for example, a photoelectric cell, and whose rotational movement is limited by a lower stop (15) and an upper stop which

  may be the sensor itself (14).

  The diagram shows only the extreme positions, the lower position corresponding to the tilting arm (13) and the pulleys (P4), (P5) and the upper position to the arm.

  tilting (13 ') and pulleys (P'4), (P'5).

  The tilting arm (13) is equipped with a counterweight (16) enabling regulation

  of the pre-tension exerted on the wire (h).

  The different tensions exerted on the wire (h), due to the working conditions (t), are transmitted to the lower pulleys (P4), (P5) which go up or down accordingly, unwinding or winding the quantity of wire (h) according to

needs of the work area (t).

  So that this winding / unwinding does not create any problem upstream, the photoelectric cell (14) communicates the situation, as has been explained, to a programmed microprocessor (gp), which orders the motor (m) to carry out the corresponding acceleration / deceleration of the system.

Claims (5)

  1.- Wire unwinding control system for EDM machines, characterized in that it comprises: a) a coil (3) wire holder rotating on an axis (4) one end of which is fixed removably to a drive plate (5) and the other end of which has a sliding fixing cone (1), capable of being fixed on said axis, bearing against the spool, the thread of the spool being sent to b ) a buffer device (11) with a regulation system, composed of fixed pulleys (P2, P3) and pulleys (P4, P5) secured to a rocking arm (13), around which the wire passes successively before arriving in the work area; c) a position sensor (14) of the tilting arm, which transmits the information it collects to a microprocessor (GP) programmed to control a motor (m) actuating the plate drive (5).   2.- wire unwinding control system for EDM machine according to claim 1, characterized in that the axis (4) has, along its length, sections of different sizes.   3.- wire unwinding control system for EDM machine according to claim 2, characterized in that the sections of different sizes are connected to each other by frustoconical portions (s) coming to engage in the surface corresponding frustoconical 6- of the bearings (o) of the corresponding size coil. 4.- wire unwinding control system for EDM machine according to claim 1, characterized in that the rocking arm (13) is provided with a counterweight (16) and in   that its stroke is limited by two stops.   5- Wire unwinding control system for EDM machine, according to   claims 1 to 4, characterized in that the   coil (3) is loaded into the machine by sliding it on a fixed loading ramp (18), after which it is automatically housed on two idle rollers (91, 92) arranged symmetrically by   relative to the axis of the drive plate (5).