Patent GB-661415-A (GB)
Title: Cam cutting machine
IPC: B24B19/12
Filed: 1949-03-09
Abstract: 661,415. Grinding cams. TRIGGS, W. W. (Fellows Gear Shaper Co.). March 9, 1949, No. 6451/49. Class 60. A machine for cutting cams comprises a supporting structure, a carriage mounted on said supporting structure with provision for rectilinear movement in a prescribed path, a work holder supported rotatably on said carriage with its axis of rotation transverse to said path, a master cam suitably connected or coupled with said holder for movement simultaneously therewith, a cutting tool operatively mounted in such relation to the carriage that the carriage, moving in its prescribed path, displaces a work piece secured to the holder toward or away from said tool, and a pantograph linkage pivoted at a fixed point on the supporting structure arranged to be moved about its pivot by said master cam and including an adjustable connection with the carriage. The work piece W, operated on by a cutting tool such as a grinding wheel G, is detachably secured to one end of a work spindle 10 rotatably mounted in bearings 11, 12 on a carriage 13 movable rectilinearly on a guide 14 secured to a base 15; a master cam C is secured to the other end of the spindle 10. The spindle 10 is rotated by worm wheel 16, worm 17 and flexible shaft 18 driven bv an electric motor. Rectilinear movement is imparted to carriage 13 by master cam C through a pantograph linkage comprising an abutment block 19 co-operating with the cam periphery, a push rod 20, a lever 21 pivoted on a fixed stud 22 on: the base 15, and a coupling member 23 connecting the lever and carriage, located between the push rod 20 and pivot stud 22 and adjustable transversely of the carriage and lengthwise of the lever. The abutment block 19 is mounted by trunnions 24 in a chair 25 secured. rigidly to a plate 26 supported from the base by parallel stiff resilient bars 27, 28; the bars are attached to the base 15 by clamps 29, 30 and at their opposite ends are connected by clamps 33, 34 to brackets 31, 32 secured to plate 26. A spring 35 anchored to the base 15 by stud 36 is connected to lug 37 on lever 21 near the thrust rod 20, so as to hold the abutment block against the cam face. Coupling 23 between carriage 13 and lever 21 is preferably a flat metal reed having resilient flexibility and being at the same time stiff enough to transmit, without buckling, thrusting force on the carriage 13; one end of the reed is connected to lever 21 by co-operating clamp bracket 38 and clamp block 39 fastened together by a screw 45; the other end of the reed is connected to the carriage by co-operating clamp bracket 40 and clamp block 41 fastened together by a screw 50. Clamp bracket 38 is secured to lever 21 by bolt 42, passing through elongated slot 43 in the lever; clamp bracket 40 is secured to the carriage by bolt 46, passing through elongated slot 47 in a part 48 of the carriage. The effective lengths of push rod 20 and coupling 23 are equal; push rod 20 has conical ends entering conical recesses 51, 52 in the lever 21 and chair 25. The slots 43, 47 extend in one direction beyond the axis of pivot 22 so that the coupling 23 can be placed in intersection with that axis, in which case no movement is imparted to the carriage when the cam rotates; in the opposite direction the slots extend far enough from the pivot axis to permit placing the coupling in a position for imparting movement to the carriage greater than the throw of the cam. To facilitate adjustment of coupling 23 a gauge plate 53 is mounted on lever 21 and has an opening bounded by parallel sides 54, 55 embracing with a sliding fit the base of clamp bracket 38 and clamp block:39; the end adjacent the carriage 13 has spaced jaws 56, 57 which can embrace closely the base of clamp bracket 40 and clamp block 41 during adjustment to ensure equal adjustment of the two ends of the coupling. In the operation of the machine, the master cam causes displacement of carriage 13 by a distance which is greater or less than the differences between its radii at different points according to' the setting of the coupling 23. Instead of the :reed 23 a link pivotally' connected at opposite ends to anchor members adjustable on lever 21 and carriage 13 may be used; instead of the spring bars 27, 28 links may be used. If the master cam has concave portions, the cam follower has convexity capable of entering the concavity, and the periphery of the cutting tool is used.