Patent GB-478755-A (GB)
Title: Improvements in or relating to machine tools for grinding and cutting metals
IPC: G02B21/00
Filed: 1936-10-08
Abstract: 478,755. Gauging work in machine tools. SPIERS, W., SPIERS, T. A., SPIERS, E., and GHAYE, A. Oct. 8, 1936, No. 27348. [Class 83 (iii)] [Also in Group XXIII] A grinding-machine, milling-machine, or other machine tool is provided with optical projection apparatus by which an enlarged image of the work may be projected on to a screen and observed while the work is being produced. In the application to a grinding- machine, particularly for making gauges, formed cutters or the like, the base 1 carries a column 12 which is vertically adjustable from a hand-wheel 13 through worm-gearing 15, shaft 18, and rack and pinion gearing 19. The upper end of the column carries a saddle 3 which is traversed horizontally by a hand-operated lead-screw 27. The column is counter-balanced by a weight 21 on a cable passing over pulleys 23, 25. A tiltable table 4 is mounted on the saddle, being guided by an arcuate rib 35 on one side and by a plain arcuate surface 37 at the other. Side plates 38 secured to the table have inturned flanges 39 engaging corresponding arcuate slots 40 in the sides of the saddle to prevent the table from lifting. Tilting movement is imparted by worm and segment gearing 43 operated from a hand-wheel 47. The table itself carries compound slides comprising a slide 6 moved by hand-wheel 66 and lead-screw 65 and carrying a transverse slide 8 which is movable on roller bearings 53 by a cam or hydraulic mechanism. The slide. 8 is fitted with a vertical slide 67 carrying a motor 9 which directly drives the grinding spindle 10. As shown the slide 8 has an extension which is slotted to receive a block 56 operated by a crank pin 57 driven from a motor 64 through worm-gearing 63. The grinding-wheel 11 is thus reciprocated through the work 80, which is clamped to a slide 73 moving on a guideway 74 carried by columns 97 extending from the, base. The optical system comprises a light source L and condenser 82 associated with an objective O consisting of a fixed lens 83 and adjustable lens 84. The image of the work, with a magnification of from 50 to 70 diameters or more, is thrown on a screen S which may comprise a sheet 102 of ground glass on the back of which a drawing of the work on which the image may be superposed is applied. The representation of the work is divided into a number of sections. One or more transparent shields may be provided to screen the projection apparatus from swarf. The light source L and objective O may be adjusted horizontally and vertically. For this purpose these parts are mounted in a bracket 88 slidable on vertical rods 90 projecting from a support 91 adjustable horizontally on a rod 92 which is itself carried by a bracket 93 movable on rods 94 carried by the column 97. The parts C and L are similarly adjustable. Micrometer adjustments may be provided if required. In a modification the work may be universally adjustable instead of the grinding-wheel and may be provided with head and tail stocks and driving-mechanism for rotating the work. For large magnifications an adjustable mirror may be provided to reflect the image of the work on to a screen located near the operator. In other modifications the work may be mounted below the cutter and the table tilted automatically by pawl and ratchet mechanism.