Patent GB-1025599-A (GB)
Title: Apparatus for cutting discs from a rod
Inventor: BOWTELL PETER LLOYD
IPC: B24B27/06
Filed: 1965-03-10
Abstract: 1,025,599. Grinding. FANSTEEL METALLURGICAL CORPORATION. March 10, 1965, No. 10228/65. Heading B3D. Apparatus for cutting discs, such as electrical contact discs, from a rod comprises means for rotating the rod, and means for feeding a cutter into engagement with the rod, the direction of feed being oblique to the axis of the rod to part off a disc with a previously formed convex end face and form a convex surface on the new end of the rod to constitute an end face of the next disc. The rod 3, Fig. 1 (not shown), which may be of tungsten or ceramic, is held by a collet 4 rotatable in a housing 2 by a beltdrive 8 from a motor 6, and axial feed of the rod after cutting off of a disc up to a stop 12 is effected by an air motor 11, Fig. 2 (not shown) when the collet is open. The cutter may be non-rotating but, as described, consists of an abrasive disc 27 carried by a motorized spindle 42 in a housing 44 which is movable along guideway 56 in a plate 57 by a hydraulic motor 53, the plate being adjustable by a hand wheel 62 along guideways 59 in a table 28 which, in turn, is movable about a pivot 29 in the bed of the machine by a hydraulic motor 32. For cutting discs having a convex conical end, the table 28 is adjusted about the pivot 28 by the motor 32 to a angle indicated on a scale 37, the motor 32 being locked to retain the table in position while the abrasion disc is fed by the motor 53. For cutting discs having convex rounded ends, the motor 53 locks the cutter in position on the table which is rotated about the pivot 29 by the motor 32. The machine is automatically operated under the control of an electro-hydraulic circuit. With the table 28 locked in position for cutting convex conical ended discs, the housing 44 carrying the cutter disc 27 is advanced and retracted by the motor 53 under the control of a valve 76, Fig. 7 (not shown), having solenoids 77, 78 operated by a relay 81 which effects advance of the cutter disc when the rod 3 to be cut makes a circuit with the stop 12 and effects withdrawal of the cutter disc when the disc has severed a portion of the rod. Upon retraction of the housing a switch 74 on the rod 67 of a stop device 72 is operated by a bracket 68 on the housing 44 to open the collet 4 and operate motor 11 to advance the rod, the contact of the rod with the stop again effecting advance of the housing and cutter. As the cutter disc wears, the bracket 68 engages a nut 68 on the rod of stop device 72 to move the rod which carries a further nut 69 which, with the nut 71 determines the limits of movement of the housing. With the housing 44 locked to the table 28 by the motor 53 for the cutting of convex rounded discs, the motor 32 is controlled by the relay 88, Fig. 8 (not shown), to rock the table about the pivot 29, the relay being actuated by the contact of the rod 3 with the stop 12. The retracted position of the table is determined by a switch 39 which controls the opening of the collet 4 and the operation of the motor 11 for feeding the rod. When the wheel wears, the further advance of the table actuates a switch 41 which operates the valve 76 to cause the motor 53 to effect a compensating advance of the housing 44 on the table. The apparatus may be used for cutting flat discs. Coolant may be supplied through a tube 65. The grinding wheel may be adjusted in a perpendicular plane so as to engage the rod at its lower periphery so that the back surface of the cut-off disc may also have a convex face.