Patent GB-165474-A (GB)
Title: Improvements in and relating to grinding machines
IPC: B24B3/04
Filed: 1919-12-24
Abstract: 165,474. Wõchtler, F. L. Dec. 24, 1919. Disc apparatus; milling-cutters, sharpening; driving and feed devices; work-holders; spindlemountings.-A machine for grinding and sharpening milling-cutters and like tools comprises a grinding-wheel 13, Fig. 1, and a mandrel 12 supported at the right hand by a headstock 10, and at the other hand by fittings shown which give it, if desired, the rotary movement necessary when grinding a helical cutter. The head-stock 10 and other cutter-supporting fittings are mounted on a carriage 9 and are traversed to and fro by a connecting-rod 7. The machine is mounted on a frame 4 and bracket 3, which can be adjusted vertically by a hand-wheel 5 and screw 6. The main shaft 1 drives, through worm-gearing, a vertical shaft 2 carrying a crank operating the connecting-rod, and carrying also a cam 15a which, by means of a roller 15 and lever 16, shaft 17, and gearing, shown also in Figs. 3, 4, and 5, rotates a spindle 18, carrying the left-hand end of the mandrel 12. A guide 62 and mechanism shown in Fig. 8 are fitted for controlling the rotary movement of helical cutters, for grinding which the grindstone support is adjusted as shown in Fig. 20; the method of mounting the grindstone spindle is shown in Fig. 18. The shaft 17, rotafed as described above, oscillates a crank-arm 41 adjustably connected to a connecting-rod 42, which in turn oscillates an arm 43, Fig. 5, and spur-wheel 44, and thus also the wheels 45, 47, 48, and the spindle 19. The wheels 45, 47 are mounted on a pin 46 in a worm-wheel 49, which can be rotated by a hand-wheel to enable the milling-cutter to be finely adjusted towards the grinding-wheel. The shaft 19 also carries, and drives through a long key 52, a spur wheel 20, which moves on the shaft 19 with the reciprocating carriage 9. The wheel 20 gears with a wheel 21, and rotates in one direction only the mandrel-supporting spindle 18. This is effected by a ring 34 and pawl 36, Figs. 3 and 4, on the wheel 21 engaging with a trip wheel 23 on the spindle 18. The rotation of the wheel 21 in the direction indicated by the arrow in Fig. 4 causes the pawl 36 to engage with the wheel 23; a reverse movement causes the lug 40 on the pawl to engage with the right-hand side of a recess 39 in an extension from a sleeve 38 which is frictionally connected by a spring 37 to the sleeve 26 on which the wheel 21 is mounted. A continuation of this reverse movement causes the heel 60 of the pawl 36 to engage with the part 38, which is then carried backwards by the wheel 21. There is thus imparted to the shaft 18 and to the cutter 11 upon it a rotary trip movement at the end of each traverse of the carriage 9, thus bringing up to the grinding disc the face of the next tooth to be ground. The rotary movement of the milling- cutter which is necessary when grinding a cutter with helical teeth is imparted by means of a guide 62, Fig. 1, and an obliquely-situated sliding carriage 55. Fig. 8. At the lower end of this carriage is roller 61 or a block which moves on the inclined guides 62, or between a pair of similar guides, and causes the carriage 55 to rise and fall; as it does so the bush 20 and the spindle 18, Fig. 3, inside it are rotated slightly by means of the chain 64, 65 which passes round the bush 29, and prevents it from rotating freely during the grinding-operation. The amount of the movement may be regulated by adjusting the inclination of the guide 62 by means of the worm 73 and handwheel 74. The chain consists of two upper parts 64 and one intermediate lower part 65, or, in a modification, Fig. 15, of straight upper and lower ends 64<2> and a stepped central part 64<1> which is wound several times round the bush 29. The lower end may be attached to a spring 84, Fig. 15, which replaces the weight 24, Fig. 8, and the bush 29 may operate the carriage 55 through rack and pinion gearing. Rotary movement of the bush 29 in the direction shown by the arrow, such as occurs when the pawl 36, Fig. 4, rotates the spindle 18, is facilitated by the tendency to unwind the chain; the contrary rotary movement, such as would be caused bv the pressure of the grinding-wheel 13 against the cutter, is resisted by the friction of the chain and the bush 29. The grinding-wheel is mounted in a head 14, Fig. 20, on an arc-shaped track 103 on the carriage 9, and is secured by a bolt 106; it is partly enclosed in a guard 104. The grinding-wheel spindle, Fig. 18, carries a belt pulley 98 which is made in one with the conical collar 89, and is heated by the friction of the belt. This causes the parts 98, 99, 89 to expand and correct the loosening of the fit due to the heating of the bearing 89, 90. The sleeve 98, 99 is adjusted by means of locking- nuts 101, 102. Reamers and the like may be ground on this machine if their axis are set obliquely to the guide table. The mandrel 12 is connected to the rotary headstock by springs 67, Figs. 1 and 3