GB596099A - Improvements in or relating to lap truing or other machines for generating curved surfaces - Google Patents

Abstract

596,099. Shaping curved surfaces. ABBEY, A. (American Optical Co.). July 18, 1945, No. 18464. [Class 83 (iii.)] [Also in Group XXIII] In a machine for generating curved surfaces on a work-piece, e.g. for trueing cast iron laps used for producing curved surfaces on lenses, wherein the cutting tool and the lap are pivoted for movement in directions mutually at right angles, the radii of the pivotal motions are increased, relatively to those normally obtainable, by the use on a standard machine of an attachment comprising a bracket 38 carrying members 42, 49 having pivots 51, 45 about which the tool and lap move. The standard machine comprises a base 5 with uprights 6, 7 in which a yoke 10 is journalled for oscillation by an adjustable crank 30. The bearing 11 on the yoke 10 normally carries a cutting tool 58 which works on a lap 28 carried in a bracket 20 pivoted at 21 on a slide 18. The slide 18 is mounted on a carriage 17 pivotally mounted on a slide 13 adjustable, in guides on the base 5, by a handle 37. The carriage 17 is moved about its pivot by a worm rotated intermittently by pawl-and-ratchet means 25, 33, a spring and pressed plunger 34 preventing back motion. When the attachment is in use, the adjusting- screw 35 of the slide 18 is withdrawn, and the pivot 45 is connected to the pivot bracket 20 by a telescopically adjustable rod 44, 46, the part 46 being screwed into the bracket 20 which is thus free to pivot about the point 45 as the ratchet 25 is operated. This effects the feeding of the lap 28 relatively to the tool 58, which latter is mounted in an extension 57 of a bracket 56 connected by spaced rods 53 to a yoke 50. The rods 53 are slidably adjustable in the yoke 50 which is pivoted at 51 to the member 49, the latter being adjustable in the bracket 38. The oscillations of the yoke 10 are transmitted to the bracket 56, and thus to the tool 58, by a connecting link 59, the movement of the tool 58 being about the pivot 51. The lap may be mounted on the extension 57 and the tool on the bracket 20 when convex surfaces are to be trued.