US 12,128,492 B2
Narrow-hole electric discharge machine
Susumu Sugawara, Kanagawa (JP)
Assigned to MAKINO MILLING MACHINE CO., LTD., Tokyo (JP)
Appl. No. 17/616,838
Filed by MAKINO MILLING MACHINE CO., LTD., Tokyo (JP)
PCT Filed Jun. 2, 2020, PCT No. PCT/JP2020/021790
§ 371(c)(1), (2) Date Dec. 6, 2021,
PCT Pub. No. WO2020/246469, PCT Pub. Date Dec. 10, 2020.
Claims priority of application No. 2019-107312 (JP), filed on Jun. 7, 2019.
Prior Publication US 2022/0347776 A1, Nov. 3, 2022
Int. Cl. B23H 11/00 (2006.01); B23H 7/30 (2006.01)
CPC B23H 11/006 (2013.01) [B23H 7/30 (2013.01)] 5 Claims
OG exemplary drawing
 
1. A narrow-hole electric discharge machine which performs electric-discharge machining on a workpiece by moving a narrow-hole electrode mounted on a spindle and a workpiece attached to a table relative to each other, the narrow-hole electric discharge machine comprising:
a positioning guide which is attached to a guide arm below the spindle and in which a lower part of the narrow-hole electrode is inserted and supported so that the narrow-hole electrode can move in an axial direction, and
a power supply element which is provided in a predetermined power supply position directly above the positioning guide of the guide arm and which directly contacts the narrow-hole electrode, which is movable in the axial direction, and supplies power thereto, wherein:
the power supply element comprises a pair of power supply brushes having a large number of bristles composed of a flexible conductive material which is thinner than the pipe electrode,
the power supply brushes are arranged symmetrically with respect to a central axis of the spindle so that each of the bristles extends in a transverse direction relative to the axial direction of the narrow-hole electrode, and the narrow-hole electrode inserted into the power supply element contacts the tips of the bristles, and
a distance from the power supply position to a tip of the positioning guide, which is closest to the workpiece, is constant regardless of the length of the narrow-hole electrode.