Patent GB-570189-A (GB)
Title: Improvements in or relating to copying machines
IPC: B23Q17/24
Filed: 1943-07-19
Abstract: 570,189. Engraving. KAPELLA. Ltd., and COOKE, E. A. July 19, 1943, Nos. 11747/43 and 6558/44. [Class 100 (ii)] [Also in Groups XX, XXII and XXIII] In a copying-machine wherein relative motion is effected between a tool support and a rotary work support in accordance with the relative movements of a tracer and rotary pattern support, either to the same or a different scale, a third rotary support is provided having means for connected it to the work and pattern supports and for locating in space a point thereon which is to form the centre of an arc to be generated on the work by the cutter. The machine comprises a frame A on which a table B is movable transversely by a screw and nut operated by a handle B<6>, a carriage C being movable longitudinally on the table by a screw and nut operated by a handle C<6>. Clamps B<7>, C<7> serve to clamp or release the nuts from the table and carriage respectively to allow free movement of the latter when required, and transparent scales B<1> , C<1> on the table and carriage are illuminated from below and cooperate with indices on the machine frame and table to indicate the settings. The tool K, consisting of a grinding disc, an end milling cutter or a stylus for marking out work, is mounted on a slide K<3> and is driven by a motor K<2> the slide being reciprocated vertically by an eccentric &c. on a cross-slide so that the cutter will act through the thickness of the work. Adjustment of the cross-slide enables wear of the cutter to be compensated and angular adjustment of the cross-slide about a horizontal transverse axis allows the direction of reciprocation to be inclined to the vertical to produce a rake on the edge of the work. The slide may also be angularly adjusted about a longitudinal horizontal axis. The work is mounted on a table E, Fig. 2a, angularly adjustable on a shaft D rotatable in bearings in the carriage C and carrying a drum F by which it is connected through a flexible band I<1> to a drum F<2> on a shaft J rotatable in the carriage C and constituting the third rotary support, the pattern support H, Fig. 2b, being mounted on a hollow shaft G and having a drum F<1> connected by a band I<2> to the drum F<2> and the drums F, F<1> being also connected by a flexible band I<3>. The bands are at different levels so that they do not cross each other and the angle of lap of each on its drum is such that the drums may be rotated through at least 300 degrees without the bands overlapping. Alternatively, the drums may be connected by toothed gearing. The table E has a toothed rim E<1> for angular adjustment of the table relatively to the shaft D by means of a pinion hand operated at E<4>, Fig. 1, and the table may be clamped to a flange D<2> on the shaft by a handle D<4> operating an eccentric D<3> to actuate a clamping bolt D<7> through. a rocking plate D <5>. The drum F<2> carries a flange F<4> which may be secured to the carriage C by a bolt F<6> and may also be secured to a flange J<3> on the shaft J by a bolt J<4>. The drums F, F\ F<2> may all be rotated simultaneously by a handle J<8> actuating a worm J<7> engaging a worm-wheel on the drum F<2>, and a handle J<9> operates means for disengaging the worm to allow the drums to rotate freely in the carriage C. the axes of the work shaft D, pattern shaft G and control shaft J lie in a plane referred to as the neutral plane when the table B and carriage C are set at the zeros of the scales B\ C' and this plane also contains the operative edge of the cutter K and the optical axis of a microscope L carried by a fixed arm L <1> and directed to view the operative edge of the cutter and the work in engagement therewith. The pattern support H carries a transparent plate M inscribed with spaced cross-lines forming a grid similar to squared paper whose origin lies at the axis of the shaft G and a hood H<8> carried by the frame is rotatable and adjustable thereon in two mutually perpendicular horizontal directions by hand-operated screws H<3>, H<4>, Fig. 5. A centrally aperttired plate G<3> attached to the hood carries three fixed fences G <5> and a movable yielding fence by which a copy or pattern M<3> may be mounted on the support H. The pattern may consist of a transparency with the shape to be copied marked thereon or may be a finished sample of the work to be produced. A transparent graticule O<3>, Figs. 2b and 12, is stationarily mounted on the frame A above a source of light N<2> and carries perpendicular scales O<1>, O<2> parallel to the lines of the grid M which are imaged in the plane of the grid by optical apparatus O<5>. The scales O<1>, O<2> represent sub-divisions of the spaces between the lines of the grid. The graticule may also carry an outline E<5> of the operative edge of the cutter which is located at the origin of the scales O<1> O<2> and this origin coincides with the origin of the grid when the latter and the work table are in the neutral position and thus constitutes a tracer for following the shape of the pattern. Two further graticules P<1>, P<2>, Fig. 12, are provided between the graticule O<3> and the grid M, each having a scale p<15> or P <16>, Fig. 47, the scales being perpendicular to each other, but each being inclined to the grid lines at an angle whose tangent is equal to one of the scale divisions O<1>, O<2> divided by the length of the scale. Movement of the carriage C to cause one of the grid lines to move its intersection with the scale P<15> or p<16> by a number of sub-divisions of the latter scales will move the carriage, and consequently the work and pattern through a distance equal to the corresponding number of sub-divisions of the divisions of the scale O<1> or O<2>. Units of adjustment of the work are thus provided by the scales B<1>, C<2>, and successive sub-divisions of these units by the grid lines, scales O<1>, O<2> and scales P<15>, P<16>. The mounting and adjustment of the graticules O<3>, P<1>, P<2> in a casing N are described in Specification 572,144, [Group XX]. The images of the scales, grid, pattern, &c. may be thrown by a projection objective L<2>, Fig. 12, and reflectors L <5>, L<6> onto a translucent or reflecting screen L<4>, Figs. 1 and 5, arranged vertically so that the enlarged images may be observed by the operator while adjusting the slides and rotary tables to cause the origin of the scales O<1> O<2> or the image of the cutter to follow the required pattern M<4>, thus moving the work in a corresponding path relatively to the cutter to produce a work-piece enlarged to the scale of the projection apparatus. Alternatively, a microscope may be mounted on the fixed bracket L<3> in place of the objective L<2> so that the images may be observed directly on the grid M, the microscope or objective L<2> being arranged in the neutral plane and spaced from the microscope L and operative edge of the tool by the distance separating the axes of the work and pattern shafts D, G. The scale of reproduction may be varied by altering the interconnecting mechanism between the three supports, e.g. by means of pantograph mechanism with or without magnification by the optical projection apparatus. Generating.-For generating circular arcs on the work, the centres of the arcs being defined relatively to an origin thereon by cartesian or polar co-ordinates, the centre of an are is set relatively to the operative edge of the cutter K by means of a radius arm Q angularly adjustable on the rotary support J and carrying a radially adjustable block R carrying a socket whose axis may be fixed in space by a spigot S on a stationary, but adjustable linkage S<4>, S<9> This mechanism is described in Specification 570,494, [Group XIX], in which Specification the radius arm is described as being mounted on the work table, but.since the work table E and rotary support J are connected as described above, the settings of the block R are transferred to the work. An electromagnetic gauge for setting the block R along the arm Q is described in Specification 570,493, [Group XIX]. Accord. ing to the first Provisional Specification, the linkage S4, S<9> may be replaced by an arm carrying the spigot S and pivoted on a slide adjustable on the machine frame, and the axes of the shafts D, G and J may be arranged at the angles of an isosceles triangle with the pattern shaft G at the apex and the shafts D. J at opposite ends of the machine in the neutral plane, or, alternatively, the pattern and control shafts G, J may be in a plane perpendicular to the neutral plane, the carriage C and frame then being L.shaped with accessories such as pumps, motors, &c. located at the back of the machine within the angle of the frame. Framings and supports ; slides and carriages.- The table 13 and carriage C are each provided on the under surface with guides A<6> engaging horizontal and inclined rollers A<2> A<3> the angle between the axes of the rollers being 60 degrees and the rollers A<3> being carried by brackets A<4> pivoted at A<5> on the frame A and table B respectively. According to the first Provisional Specification the table and carriage may be mounted on ball tracks. Specifications 481,591. 499,751 and 538,726 are also referred to.