Patent GB-744137-A (GB)
Title: A new or improved surface shaping machine
IPC: B23Q35/10
Filed: 1952-08-16
Abstract: 744,137. Copy-milling; copy-planing. BAIN, J. J. Nov. 9, 1953 [Aug. 16, 1952; Aug. 18, 1952; Aug. 25, 1952; March 9, 1953], Nos. 20647/52, 20676/52, 21251/52 and 6505/53. Class 83 (3). A machine for shaping aircraft wing-panels and other shapes comprises a work support 158, Fig. 1, for moving a workpiece relatively to the axis of a rotatable mill 163, a tool-holder 171 guided on the mill for movement having a component parallel to the mill axis, and a follower 172 on the mill engaging a control surface 173 on a support concentric with the mill axis for controlling the tool 170. In a vertical milling- machine the mill or cutter shank is secured in a screwed recess 164 in a spindle 162. The cutter carries one or more tools 170 on bellcrank levers 171 secured in slots in the cutter periphery. The ends of the levers are formed as followers 172 to contact the pattern surface 173. The pattern is non-rotatably supported by a yoke 178, the vertical movement of which is controlled by a template 169 mounted on the work-holder 158 and co-operating with a follower 180 carried by a rod 167 to which the yoke is secured. The surface 173 may be formed to control the tool to effect a roughing cut at the leading side of the cutter and a finishing cut at the trailing side, the work being of less width than the diameter of the tool path. In a modified machine, columns 5, Fig. 3, on the machine bed 4 or the floor, carry vertically-adjustable guides 22 for a cross beam 21 supporting a head 24. The mill 25 is supported on the head 24 by rollers 29 and is rotated by a motor 32 through gears 35, 31. One or more tools 56 are each rotated through a splined connection 61 by a motor 63 which receives its current through a slip-ring. The tools are each mounted on a slide 57 which may be counterweighted and which is controlled by the cam surface 73 through a lever 67, the cam being non-rotatably supported by a bar 19 carried by columns 15 resting on cams 12 at each side of the worktable 1. The table is traversed by a motor 6 through rack-and-pinion gearing 10, 11. The followers 71 are held in contact with the cam 73 by springs 77. The cam 73 may be formed to give roughing and finishing cuts as in the machine of Fig. 1. The cutter 56 may be replaced by an end-mill having a vertical axis or by a single-point tool. To obtain work of opposite hand, the cams 12 are reversed and the cam 73 is inverted. To obtain mating work, means may be provided to reverse the action of the lever 67 and thus the movement of the slide 57. The tools are lubricated by gravityfeed from a channel 52 and pipes 54. In a similar machine shown in Fig. 4, each tool-slide 86 is counterweighted by a weight 48 and cable 45. The operating lever 92 may be pivoted on a bracket 93 for the production of a mating surface. The cam 135 in this machine comprises a square block 83 to which cam surfaces are attached. To maintain a constant cutting angle, a similar cam 47 controls the position of a circular slide 88 carrying the tool 105 through a follower 104, a rack-and-pinion 101 and bevels 96, 89, the slide movement being about an axis containing the cutting point. The follower and cam are held in contact by a spring 113, Fig. 7, and may be rendered inactive by a collar and nut applied to the end of a screwed rod 109 carrying the spring. Pins 127 on the rods 15 of this machine and that shown in Fig. 3 are attached to counterbalancing weights 130, Fig. 16. To produce work of opposite hand, the cams 83, 47 are inverted, the cams 12 are reversed longitudinally of the table 1, the operating members for tilting the tool 105 are reversed, and the bias spring 113 is reversed. To produce work of mating form, the cams 83, 47 are inverted and the cams 12 are reversed as before, and the lever 92 and spring 125 are reversed to reverse the direction of movement of slide 86. The linkage between a tool and its follower may be in part by mechanical, electrical or fluid pressure means. Thus a " make- and-break " contact may control an electric motor having geared connection with the toolholder or an electrical quantitative indicating- means may control a motor through an amplifying circuit. Alternatively, the opening of an air-jet nozzle contacting the control surface may operate the tool-holder. The cutter may be a milling cutter rotated by a pneumatic motor and the biasing means may be pneumatic instead of spring. Thus a pump 153, Fig. 3, driven by gearing 157 supplies pressure air to a cylinder 155 biasing a tool-holder 57. A valve 156 permits the bias to be reversed. The control bodies may be moved by an electric motor. In a further modification, the work is carried on supports 139, Fig. 17, rotated by a motor 143 through gearing 142. The motor also rotates cams 146 (which may be reversed for work of opposite hand) which take the place of the cams 12. In yet another modification a rotatable work-support 148, Fig. 18, passes between the pillars 5, and the cams 12 are replaced by cams 151, 152 on the work-support, the mill axis being indicated at 150. The cams 152 serve as return cams between the cams 151 which control the operations on successive workpieces.