Electrode Feed and Wear Compensation Mechanism for Electrical Discharge Machining Apparatus

摘要

1,177,822. Electro-erosion. ELOX CORP. 16 March, 1967 [3 June, 1966], No. 12494/67. Heading B3V. [Also in Division G3] An electro-erosion apparatus has its electrode 18 fed by a servo feed system 22, 61, including a reversible drive means 22 which also actuates a control means 44 co-operating with an adjustable stop 52 which upon engagement effects reversal of the electrode. The latter is wire 18 fed from an adjustably mounted spool 16 through aperture 19a, and tubes 36, 38, by a knurled feed roller 61 mounted on the shaft 48 of the reversible drive motor 22. Feed roller 61 co-operates with adjustable backing- up rollers 24, 26, 28, (84), Fig. 4 (not shown). The motor shaft is connected through a backlash inhibiting coupling 64 to an extension of shaft 48 which carries two arms 44, 46 biased by spring 69 into frictional drive engagement with the shaft 48. Arm 46 co-operates with an adjustable stop 56, 58 set to the actual depth of cut, and arm 44 co-operates with another adjustable stop 52 set to allow for the depth of cut plus wear in the electrode during cutting. When arm 44 engages stop 52 it actuates a switch SW1 to reverse the motor 22 and withdraw-the electrode. Both arms 44, 46 are also driven in reverse until arm 46 engages a second switch SW2 to stop the motor 22 and to energize a solenoid 65 which returns the other arm 44 to its starting position against stop 50. The electrode/workpiece gap is supplied with power from a pulse generator 89, Fig. 5, and the feed motor 22 is controlled by a gap voltagesensing network which feeds the motor armature 98.