Patent GB-1466039-A (GB)
Title: Sharpening machine for root-cutting knives
IPC: B24B3/58
Filed: 1975-04-14
Abstract: 1466039 Multiple operation machine tool; milling grinding workpiece transferring RAFFINERIE TIRLEMONTOISE 14 April 1975 [12 April 1974] 15234/75 Headings B3B B3K and B3D A multiple operation machine tool for sharpening root-cutter knives comprises a vice like knife clamping device 3 mounted on indexable conveying means 1 whereby a knife may be sequentially located in a rough grinding station 7 a course milling station 8, a finish milling station 9, a deburring station 10 and finally to removal and magazine station 6. In the embodiment described the conveying means 1 is in the form of a rotary indexable table on which are mounted four equally spaced knife clamping devices 3. The magazine in the station 6 feeds a knife blade by reciprocating fluid pressure means 612 to the jaws 310, 323 of the clamping device 3, the table is then indexed to bring the knife cutter into the grinding station 7 where a preliminary grinding operation is effected by the grinding wheel 710 which is displaceable towards and away from the knife cutter by motor operated slide 712 and longitudinally thereof by hydraulic jack 717. The table 1 is then indexed to bring the pre-ground knife into the course milling station 8 where the serrated edge of the knife is machined by a form milling cutter 812 which is feed stepwise transversely along the knife edge to mill the individual serrations of the knife edge. This completed, the table is indexed to bring the clamping means 3 with the knife cutter into the finished milling station 9 whereat the final cutting edge is machined on the knife by a form cutter in the same way as at the course milling station. The table is subsequently indexed to bring the finished knife back to its usual position at the station 6 where the finished knife is rejected and a fresh knife is fed from the magazine to the knife clamping device 3. Interposed between the finished milling station 9 and the magazine station 6 there is provided a deburring device 10 in which the finish milled knife passes between a pair of rotating brushes to remove burrs produced in the machining operation. In the machine tool described the four knife clamping devices 3 simultaneously carry the blades through the machining stations and the indexing sequence of the rotary table 1 is interconnected by way of time switches and stops so that the whole sequence of the machining of the cutter blades is effected automatically. The clamping devices are pivotably mounted on the table so as to permit tilting of the assembly with the blade 12 clamped between the jaws 323 and 310, the clamping being effected by operation of the fluid means 5 which actuates the jaw 323 through a link mechanism, the whole assembly being pivotable about the axis 4, the extent of pivoting being controlled by the screw stop 346. The coarse and finish milling devices at stations 8 and 9 respectively are similar in construction and operation the cutter 812 (or 912) being mounted on shaft 811 which is carried by a pair of levers 817 pivotable by a rotary cam 815 to feed the cutter into the individual serrations on the cutter knife 12. The pivoting of the milling cutter arms 917 effecting the engagement of a stop 823 with the cutter knife 12 to pivot the clamping device and bring the knife 12 and milling cutter 812 into engagement. At the end of each in-feed and return motion of the milling cutters rack and pinion means is actuated to displace the milling cutter transversely to the next serration of the knife cutter. The whole operation being controlled automatically