GB650541A - Improvements in or relating to engraving machines - Google Patents

Abstract

650,541. Copy-milling machines. LEA, N. Oct. 29, 1947, No. 28911. [Class 83 (iii)] [Also in Group XVI] A pattern-controlled copy-milling or engraving machine comprises a ratio arm carrying a tool 1 at one end and a tracer 16 at the other end, the arm being supported and restrained longitudinally by a universal mounting 4 fitted intermediate its ends and adjustable in position to vary the reproduction ratio without moving the arm longitudinally in relation to the work. A tool head carrying a motor 13 and the ratio arm is vertically adjustable on a pillar 46 by means of a screw 41 and a clamp is provided for securing it in the adjusted position. A yoke 15 connects the tracer 16 to a sleeve 2 surrounding the tool spindle 1, the upper end of which bears against a thrust screw 17, and the spindle is driven by a belt 12 and a skirted pulley 10 which rests on the upper end of the sleeve 2 and is connected to the spindle by a screw 11. An arm 51 engaging a slot 52 in the machine frame prevents rotation of the yoke 15. The universal mounting of the ratio arm comprises a ball-shaped nut 4 screwed on the sleeve 2 and seated in a conical or sphericalshaped hole in a member 7, a slot in the nut engaged by a peg on the member 7 preventing relative rotation of the parts and a spring 18 holding them in contact. The nut 4 and member 7 have threads of the same pitch and, to vary the scale of reproduction, the universal mounting may be adjusted along the spindle by rotation of the member 7 in a split screwed sleeve 9 attached to the tool head; the ratio of reproduction may be indicated by a scale on the tool head. Clamps 25 hold the work on a table 24 which is adjustable, by means of a screw 31, on a U-frame 26 which is itself pivoted on a rod 27 and adjustable along the rod by a screw transverse to the screw 31. A flat spring 33 holds the table 24 against the frame and slides along the arms of the frame. A cam 38 rotatable by a handle biassed by a spring and pin mechanism 40 raises or lowers the frame to and from the working position, the initial adjustment being set by a screwed rod 35. The tracer extends through the pattern 21, which may comprise a stencil located by a pin 22 on a slide 20 and placed right side up or turned over for " mirror " engraving. Alternatively, the tracer may be bent over to engage the pattern from above or may comprise cross-lines on a transparent plate moved over or optically projected on the pattern. Observing tools and work.-A lens 49 mounted in a frame hinged at 50 and a lamp 48 are provided.