| 摘要 |
The invention relates to a process and device for centre marking the circular part surfaces, particularly the front sufaces of shafts in the machine building industry. The centre marking process comprises a first step wherein two line segments perpendicular to each other are made to contact the outer surface of the part, there resulting two tangent points. Two feelers which are also in contact with the outer surface of the part are symmetrically located on both sides of each tangent point so that two chords result. An imaginary line is drawn perpendicularly to the midpoint of each chord, said lines coinciding with two diameters perpendicular to each other, the intersection point thereof coinciding with the centre of the circular surface to be marked on the part. The device for applying the process comprises a frame (1) with two arms ( a and b) forming an angle of 90 degree therebetween, a slide (2) gliding along each of said arms. Two sensing bolts (3) provided with a ruler (5) equally spaced therebetween, integral with a slider (2) and provided with a groove (c), are fastened on each slider (2). A sliding support (6) with a bushing guide (7) of a punch (8) is movable along one of the rulers (5).
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