GB2309708A

GB2309708A - Unwinding electrical wire:tension control

Info

Publication number: GB2309708A
Application number: GB9602192A
Authority: GB
Inventors: Alberdi Carmelo Onandia
Original assignee: Ona Electro Erosion SA
Current assignee: Ona Electro Erosion SA
Priority date: 1996-01-30
Filing date: 1996-01-31
Publication date: 1997-08-06
Also published as: DE19603525A1; FR2744110A1; GB9602192D0

Description

1 SYSTEM WITH CONTROL OF UNWINDING OF WIRE FOR ELECUMCAL DISCHARGE FORMNG

MACIfiNE 2309708 The need to control the winding or unwinding of wire in electrical discharge forming machines in order to prevent breaks, crossing or tangling in the loops which may be produced from occurring due to the variability of tensions to which the wire is subjected, is well known.

Also well known are systems for said control, but they suffer from complexity, which gives rise to excessive maintenance and price; nor do they afford versatility for the use of reels of wire of different sizes.

Ilese problems are solved by the invention which presents a system with control of unwinding of wire for electrical discharge forming machines, which is characterised in that it consists of..

a) a wire-bearing reel which rotates on a spindle which at one end is connected detachably to a driving plate and at the other comprises a slidable fixing cone which can be fixed to said spindle and which is positioned against the reel, the wire of the reel being sent to b) a storage regulating device which consists of some fixed pulleys and some pulleys connected to a swinging arm, over which the wire passes successively before going to the working zone; c) a swinging arm position sensor which supplies its information to a programmed microprocessor and which controls a motor for actuating the driving plate.

In order to understand the subject of the present invention better, a preferred embodiment is shown in the drawings, capable of incidental changes which do not impair its basis.

Figure 1 is a schematic side view in section of an embodiment of the system which is the subject of the invention.

Figure 2 is a front view of the embodiment of Figure 1.

The wire (h) to be used in the electrical discharge forming machine comes T 1 2 from winding of the reel (3) which rotates on the spindle (4).

A motor (m) with its reduction gear (r) is provided, which actuates a driv g plate (5) which rotates on a fixed support (6).

The driving plate (5) comprises a threaded blind orifice (b) and some driving bolts (7).

The reel (3) slides for loading thereof in the machine on a fixed loading chute (8) and is placed on two idler rollers (91), (9 which are positioned symmetrically in relation to the axis (e) of the driving plate (5) and which position the reel (3) coaxially with said driving plate (5), engaging the driving bolts (7) in the corresponding connected recesses of the bases of the reel (3).

The spindle (4) which is introduced into the axial journals (0) of the reel (3) which each comprise a frustoconical surface (s) towards the exterior, comprises a threaded end (10) which is screwed into the blind orifice (b) of the driving plate (5) and a fixing cone (1) at its other end which is screwed (a) in the fashion of a nut onto the spindle (4) and which engages with the corresponding frustoconical surface (s) of the reel (3), adjusting its position.

The spindle (4) has different sizes of sections along its length, the junction between them being by mews of frustoconical surfaces (2), which allows the use of reels (3) of different sizes which would be inserted between the fixing cone (1) and the corresponding frustoconical surface (2) of the spindle (4).

Ile wire (h) leaves the reel (3) towards a pulley (P) and from there to a wire storage regulating device (11) which consists of several upper pulleys (P2), (P3) and several lower pulleys (P4), (P.) on which the wire produces several loops (12) which act as a store of wire (h).

lle path of the wire (h) in this embodiment is the following: reel (3) pulley (P) - upper pulley (P3) - lower pulley (P.J--- upper pulley (P2) -lower pulley (P4) work (t).

The lower pulleys (P4) (P.) are arranged on a swinging arm (13) of which the positioning is detected by a sensor (14), for example, a photoelectric cell, and of which the rotary movement can be performed between a lower stop (15) and an upper 3 stop which can be the sensor (14) itself.

Only the end positions have been shown, the lower one being swinging arm (13) and pulleys (P4), (P.), and the upper one swinging arm (13) and pulleys (74), (P15).

Ile swinging arm (13) has a counterweight (16) for regulating the pretension on the wire (h).

lle different tensions on the wire (h) by the conditions of work (t) are transmitted to the lower pulleys (P4), (P) which move up and down, hence supplying wire (h) to and removing it from the work zone (t).

So that said supply and removal does not give rise to problems upstream, the photoelectric cell (14) communicates this circumstance of the mode already explained to a programmed microprocessor (gp), which imparts to the motor (m) the corresponding acceleration and deceleration of the system.

4

Claims

1. System with control of unwinding of wire for electrical discharge forming machines, characterised in that it consists of:

a) a wire-bearing reel which rotates on a spindle which at one end is connected detachably to a driving plate and at the other. comprises a slidable fixing cone which can be fixed to said spindle and which is positioned against the reel, the wire of the reel being sent to b) a storage regulating device which consists of some fixed pulleys and some pulleys connected to a swinging arm, over which the wire passes successively before going to the working zone; c) a swinging arm position sensor which supplies its information to a programmed microprocessor and which controls a motor for actuating the driving plate.

2. System with control of unwinding of wire for electrical discharge forming machine according to the above claim, characterised in that the spindle comprises longitudinally sections of different size.

3. System with control of unwinding of wire for electrical discharge forming machine according to claim 2, characterised in that the sections of different size are connected by truncated cones which engage with the corresponding frustoconical surface of the journals of the reel of corresponding size.

4. System with control of unwinding of wire for electrical discharge forming machine according to claim 1, characterised in that the swinging arm is provided with a counterweight, its movement being limited between two stops.

5. System with control of unwinding of wire for electrical discharge forming machine according to the above claims, characterised in that the reel is loaded by sliding on a fixed loading chute and placed on two idler rollers situated symmetrically in relation to the axis of the driving plate.