Patent GB-480661-A (GB)
Title: Improvements in engraving machines
IPC: B23Q35/20
Filed: 1936-05-19
Abstract: 480,661. Grinding. KAPELLA, Ltd., and RODWELL, R. V., TAYLOR, E. M., and STAFFORD, G., [Representatives of TAYLOR, W.]. May 19, 1936, No. 30.593/37. Divided out of 480,584. [Class 60] [Also in Groups XVI and XXII] An engraving or like machine, wherein the tool employed may comprise a grinding-wheel, an end mill or a stylus, and intended for making scale copies of a pattern or other copy, comprises a lever arm C pivoted about a primary axis D in brackets E<1> on a base E, a work . shaft A carrying a work-table A<1> and a copy shaft B carrying a copy table B<1> being rotatable in bearings in the arm C and geared together so as to rotate synchronously by helical gearing A<2>, B<2>, F<1>, F<2> operated by a hand wheel. A tracer G, for engaging the copy is carried by a support G slidable, at right-angles to the axis D, on a slideway E<2> the plane passing through the axis D and the operative point of the tracer forming a primary or datum plane for the machine ; when the arm C is in zero position, the work and copy shaft axis also. lie in the primary plane. The tool, shown as a grinding-wheel H, is carried on a horizontal shaft H' in a casing H<2> reciprocated up and down on a slideway J<1> by a lever K and a cam K<2>, the slideway being on a bracket J, which is adjustable to and from the work so as to adjust the operative point into the primary plane and to take up wear, on a slide L<1> ; the slide L<1> is on a member L mounted by an arcuate guide M<1> on a support M, so that the line of reciprocation of the wheel may be inclined to the vertical to produce a front rake on the work. The support M is slidable on the slideway E<2> and the movements of the wheel H and the tracer G are controlled so that the ratio of their distances from the axis D remains constant and equal to that of the distances of the shafts A, B, by a differential screw mechanism, or as shown, by a pantograph N pivoted at N<1> to a bracket E<3> and at N<2>, N<3> to the tool and tracer supports, respectively. Adjustment of the wheel and tracer &c. is facilitated by microscopes or other sighting devices O, O<2> carried by arms O<1>, O<3> on the arm C. In order to maintain datum lines on the work and copy tables parallel to a given direction, an arm P extends from the work shaft, and is pivoted to a link P<1> pivoted at its other end at a point P<2> on the base E, the distance of the point P<2> from the axis D being equal to the length of link P and the length of link P being equal to the distance between the axis D and the work shaft axis ; the arm P, in operation, is clamped to the work shaft. In operation, the arm C is swung about the axis D and the supports G<1>, M, are moved along the slideway E<2> so as to cause the tracer point to traverse the copy, which may be in the form of a drawing, in which case the arm may be clamped whilst taking a cut. When a wheel H having a V-section with a radiused edge is used, the circular edge and the profile of the tracer must correspond, but the flanks of the wheel profile may be less obtuse than those of the tracer. There may be two planes through the primary axis containing respectively the operative points of the tool and tracer, the work and copy shaft axes. also lying in two planes making the same angle. The work and copy tables may be arranged at such distances from the primary axis D as to give a reduction, an enlargement or equality between the copy and the work. The machine may be applied to three-dimensional work in a manner similar to that described in Specification 418,135, [Group XXII]. The grinding-wheel may be trued by a diamond, &c. mounted on the worktable, a follower having the same outline as the diamond being mounted on the copy table. Specifications 480,663, 480,664, and 480,6(iS also are referred to.