Patent GB-570494-A (GB)
Title: Improvements in or relating to copying machines
IPC: B24B17/04
Filed: 1943-07-15
Abstract: 570,494. Milling-machines. KAPELLA, Ltd., and COOKE, E. A. July 15, 1943, No. 11544. [Class 83 (iii)] [Also in Groups XIX and XXIII] In a copying-machine having a work support which is movable and rotatable relatively to a tool, and a radius arm on the work support carrying a member which may be secured thereto in any radially adjustable position and which may also be fixed relatively to the machine frame so as to locate a point on the work support at a fixed position in space about which circular arcs may be generated on the work, as described in Specification 499,751, a linear dimension gauge is provided on the radius arm to locate the adjustable member thereon and so determine the radius of the arc generated. The machine comprises a frame A, Fig. 2, carrying transverse ball bearing ways A<1> for a carriage B provided with longitudinal ball bearing ways A<3> for a table C in which the rotatable worksupport C<4> is mounted. The support C<4> may be rotated by a worm F<7> and a hand wheel and is connected by an idle gear F<6> to a rotatable support D<3> on the table C so that an image of an enlarged pattern D<5> carried by the support D<3> thrown onto a screen D<2> by an objective D<1> may be observed by a microscope F<2>, Fig. 1, during movement of the work. Another microscope E<1> is provided for observing the tool E<3> and the work, both microscopes being carried by a frame E fixed to the machine frame A and being spaced apart at the centre distance of the work support C<4> and image support D<3>. For normal copying, the carriage B and table C are traversed by hand-operated nuts C', B<1> and the supports are rotated by the hand wheel F<9> of the worm F<7> to cause the microscope E<2> to follow the image on the screen D<2>, the operative edge of the tool E<3> being located on the axis of the microscope E<1> and the tool being reciprocated on vertical guides E<5> to cut through the thickness of the work. The guides E<5> may be inclined to the vertical to produce rake on the edges of the work. To produce straight lines on the work at any required angle, the support C' is rotated to bring the line parallel to the primary plane containing the axes of the microscopes and then locked by a handle F<3> to the table C, and the carriage B is then moved to bring the line into the primary plane, and locked in this position by a clamp B<2>, after which the table C may be traversed by the nut C<1> to move the work on the required line relatively to the tool. For generating circular arcs on the work, a radius bar G, Figs. 2 and 6, is attached to a flange C<7> on the spindle C<3> of the work support C' and carries a block H slidable along guides G<1>, G<2> on the bar. For setting the centre of an arc to be cut on the work relatively to the tool, the position of the centre being defined by polar co-ordinates on the work, the support C<4> is set in zero position, i.e. in axial alignment with the microscope E<1>, the block H is set along the arm G with the axis of a socket H<8> thereon at a distance from the zero position equal to the radius of the required arc and clamped thereto, the arm being perpendicular to the primary plane. A spigot M on an adjustable link M<5> pivoted to a fixed base A<2> is inserted in the socket H<8> and secured therein by a screwed spindle N<2>, after which the pivot points of the link M<5> are clamped so as to fix the position of the socket relatively to the machine frame. The support C' is next rotated about its axis through the angle specified by the polar co-ordinates, thus bringing the centre of the required arc in alignment with the socket H<8>. The support C' is then locked to its spindle C3 by a clamp C<6>, the pivots of the link M<5> are released, and the slide B is moved to bring the arc centre to a point separated from the primary plane by the radius of the arc so that its circumference is in this plane and in line with the operative edge of the tool, the side of the primary plane on which the centre is located determining whether a convex or concave arc will be generated by the tool. The pivots of the link M<5> are finally tightened and the arc may be generated about the axis of the socket H<8> by rotating the handles B<1>, C' to traverse the carriage B and table C as required in directions tangential to the arc, the support C<4> being allowed to rotate about its axis. Alternatively, the table C<4> may be locked to the table C and released from the lower end of the shaft C<3> by releasing the lock F<2>, the table C then being given a connecting rod motion by rotation of the lower end of the shaft C<3>, which acts as an eccentric in the table C, thus moving the required point on the work secured to the table C<4> in a circular arc relatively to the cutter. Rotation of the shaft C<3> may be caused by the worm F' engaging the flange F<1> thereon or by rotating the arm G directly by hand. To set the centre of an arc to be generated on the work specified by Cartesian co-ordinates, the support C<4> is locked to the table C by a clamp F<3> and released from the shaft C<3> and radius arm G by unlocking the clamp F<2> and the block H is released from the arm and the socket H<8> locked by the link M<5>. The carriage B and table C are then traversed by their nuts B<1>, C<1> through distances equal to the specified ordinates which are read off on micrometer scales on the nuts, the socket H<8> remaining stationary, but the radius arm G rotating about the centre of the shaft C3. The block H is then clamped to the arm G, and the support C<4> to the shaft C<3> and the pivots of the link M<5> released, after which the carriage B is moved to bring the periphery of the arc into the primary plane. The link M<5> may then be locked and the support C' released from the table C to enable the arc to be generated by movements of the carriage and table. For setting the radial position of the block H on the arm G, a gauging device is used which is described in Specification 570,493, [Group XIX], and comprises a feeler J, Fig. 6, slidable in the block H co-operating with an adjustable abutment J<6> on the arm G and acting through levers K<1>, K<2> on a mechanical or electromagnetic device L which controls an indicator on the base of the machine.