Patent GB-480584-A (GB)
Title: Improvements in engraving machines
IPC: B23Q35/20
Filed: 1936-05-19
Abstract: 480,584. Grinding. RODWELL, R. V., TAYLOR, E. M., and STAFFORD, G., [Representatives of TAYLOR, W.], and KAPELLA, Ltd. May 19, 1936, No. 14129. [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 model or other copy, comprises a base A in brackets A<1> of which is pivoted on an axis B, termed the primary axis, the link B<1> of a pantograph, the other three links B<2>-B<4> of which are pivoted to the link B<1> or to one another at B<5>-B<8>, whilst the link B<3> is extended and carries, on an axis B<9> lying in a plane containing the axes B, B<7>, the shaft J of a copy table ; the work is carried by a table H<1> on a shaft H the axis of which is the axis B7. A tracer C, intended to engage the outline of the copy, and having an operative part of a form corresponding to that of the tool, is carried on a bracket C' on a block on the base A and its operative point lies in a plane, termed the primary plane, passing through the axis B ; in the zero position of the pantograph, the axes B<7>, B<9> also lie in the primary plane. The tool, shown as a grinding- wheel D is mounted on a horizontal shaft D<1> parallel to the primary plane in a casing D<2> carried on the head D<5> of a plunger which is reciprocated up and down, by a lever D<7> operated by a rotating cam E<4>, in a cylinder E<1> forming part of a cross-slide E ; the slide E is adjustable by a hand wheel E<7> to maintain the operative point of the wheel D in the primary plane. The slide E is mounted on an arcuate guideway E<9> so that the direction of reciprocation of the wheel D can be inclined to the vertical to impart a front rake to the work. A microscope F is mounted on a bracket F' on the link B<2> to aid in the setting of the work, and a microscope G, on a bracket G<1>, is provided for setting the copy. The work shaft H and the copy shaft J may be rotated synchronously and for this purpose they are connected by gear-wheels K<2>-K<4> in a casing K and gear-wheels K<5>. . K<7> in a casing K<1>, the wheels K<4>, K<5> being formed integrally, and the casings being pivoted about the axes of the wheels K<2>, K<4>, K<7>. In order that datum axes on the work and copy tables may remain parallel to a fixed line, orienting mechanism is provided comprising an arm L, which may be clamped to the work shaft H and is pivoted to the arm L<2> of a bellcrank lever pivoted about the axis B<5>, the other arm L<3> of the lever being pivoted to one end of a link L<4>, the other end of which is pivoted at L<5> to the bracket A'; this arrangement forms two parallelogram linkages. The work table H<1> is secured to the top of the shaft H, which is mounted in bearings in a sleeve mounted in the link B<2>, and the copy shaft J is similarly mounted in a sleeve J<1> secured to the link B<3>. The shaft J carries at its upper end the lower part J<3> of the copy table, an upper part J<2> thereof being angularly adjustable on the part J<3> and adapted to be locked thereto by bolts J<4>. The synchronous rotation of the shafts J, H is brought about by a hand wheel M on a spindle M<2> in a casing M<1> on the sleeve J<1>, the spindle having thereon a worm M<3> engaging a worm-wheel J<6> fixed to the copy table part J<3> ; the spindle M<2> is eccentrically mounted in a rotatable bushing M<4> so that the drive may be disconnected. In operation the copy mounted on the table J<2> is moved so as to cause the outline of the copy to move over the operative point of the tracer, the work and copy tables being at the same time rotated synchronously, as required, by the hand wheel M; when the copy is in the form of a drawing the pantograph may be clamped whilst taking a cut. When a wheel D 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. The work and copy tables may be arranged at such distances from the axis B to give an enlarged scale. 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. moved under control of the pantograph. Specifications 480,661, 480,663, 480,664, and 480,668 also are referred to.