Patent GB-641931-A (GB)
Title: Improved method of and apparatus for milling metals or other substances
IPC: B23C3/00
Filed: 1944-07-07
Abstract: 641,931. Milling-machines. PRECISION SHAPES, Inc. July 7, 1944, No. 13019. Convention date, June 17, 1943. [Class 83 (iii)] [Also in Group XXIII] in a machine for the continuous milling of strip metal or other material, one or more strips are drawn under tension through a positioning jig or holder into which project one or more cutters mounted on a common arbor. The materials operated upon may include steel, (alloy or otherwise), brass, phosphor bronze, aluminium or aluminium alloy such as that known under the Registered Trade Mark " Duralumin," magnesium alloys, fibre and plastics such as that known under the Registered Trade Mark " Lucite," and the machined strips may subsequently be cut into separate articles. The machine comprises a head 4, Fig. 1, carrying the cutter spindle 7 and work support 23 and a draw bench 64 for pulling the strips 35 through the head. The cutters 6, Fig. 9, are spaced on an arbor 7 rotatably mounted at 14 in the head and driven by gearing 13 and a belt from an electric motor 10. The work support 23 is longitudinally adjustable by a hand wheel 26 on a carriage 23<SP>1</SP> which is vertically adjustable on the head 4 by a hand wheel 27. The strips slide through slots 34, Fig. 15, in a jig plate 32 carried by a base 22 adjustably secured by bolts 24 to the support 23, the slots being closed by interlocking plates 37 which are clamped to the plate 32 by screws 46 so as to engage the strips frictionally and apply the desired tension as they are pulled through. Recesses 36 in the plate 32 and 43 in the plates 37 provide clearance for the milling cutters to allow them to cut grooves, chamfers &c. in the strips or to bevel the edges thereof or produce any required cross-section thereon, or cut completely through the strips. Alternatively the grooves 34 may be' of the same depth as the strips or shallower and the cover plates 37 pressed into contact with the strips by springs abutting on headed pins attached to the jig 32. For slitting strips into narrower strips a separate jig may be provided for each strip and consists of a lower plate 52, Fig. 26, grooved at 53 to receive the strip 51 and having a one-piece cover 54 attached thereto by screws. Slots 56 in the cover allow penetration of the cutters 57 and the jig is secured in a U-shaped clamp 58 on the support 23 by bolts 60. The strips may be pulled through the head 4 by chains 61-63, Figs. 1 and 3, passing over idler sprockets 67, 73 and driving sprockets 70 rotated from a motor 81 through change-speed gearing 82 and belts 79. A plate 89 on each chain carries two bevel-ended pins 91 to engage adjacent rollers on the chain and is tied by members 87, 100 to a clamping plate 99 on which one or more of the strips 35 are attached by screws and plates 101. The chain tension may be adjusted by a tensioner 86 and the strip tension by turnbuckles in the members 87. In operation, a narrow leader strip 35a, Figs. 1 and 15, which will clear the cutters is first passed through a slot 34 in the jig 32 and clamped at 99 to the chain grip 89 and at 106 to one or more work strips 35 at some distance from the ends of these strips. With the cutters 7 rotating, the grip 89 is engaged with its chain and the strip 35a is pulled through the jig to enter the strips 35 in their appropriate slots 34. When these strips 35 have passed through the jig in contact with the cutters their leading ends are secured by a further grip 89 to the chain, the clamp 106 is transferred to connect these strips to another set of work strips, the leader strip 35a is removed, and then the new strips are pulled through the jig, each set of new strips being subsequently connected by a clamp 106 to a set of strips which has already passed through the jig and been attached to its chain. Alternatively the strips 35 may be passed initially through the jig by a rectangular frame 107 ... 109, Fig. 27, clamped at 110 to a chain and at 109 to the strips at a point remote from their ends as shown. When the strips have passed through the head 4 to the position shown the frame is removed and the ends of the strips attached directly to the chains by the grips 89. The side members 107 of the frame slide in grooves in the edges of a guide 113a attached to the support 23 and having grooves and cover plates 113 for the strips. As each grip 89 reaches the sprocket 73 the pins 91 enter between the sprocket teeth and are then forced out of contact with the chain thereby. If the strips should become bent by the action of the cutters thereon a correcting bend may be applied to them by offsetting the pull of the grips 89. To accomplish this horizontally the chains are offset by adjusting the sprockets along their shafts and for vertical bending the framework 66 carrying the chains is adjusted vertically by means of screws 65 engaging the floor. The strips may be drawn through the head 4 by screws or hydraulic cylinders instead of chains. lubricating cutting tools and work.-A motordriven pump 30, Fig. 9, draws coolant from a tank 29 in the base and delivers it to nozzles 31 over the cutters 6, the coolant then being filtered and returned to the tank. Cutter arbors and mountings; cutters.-The cutters 6, Fig. 10, are spaced by collars 8 on the arbor 7 in accordance with the shapes to be produced on the work strips 35. A nut 15 screws on an enlarged portion 16 of the arbor to secure a cover 14 for the arbor bearings and the end collar 9 is keyed at 18 to the portion 16 for driving engagement. The end face of the collar 9 is in vertical alignment with the edge 321 of the work support 32 to facilitate setting of the cutters. The cutters may be cylindrical or bevelled as at 50, Fig. 14, to produce chamfers on the work 35, or of other shape. Gauging-devices.-In order to' adjust the depth of cut the work-supporting carriage 23<SP>1</SP>, Fig. 9, is adjusted vertically relatively to the cutters 6 by means of a graduated hand wheel 27 and a pointer 28.