Patent GB-190706880-A (GB)
Title: Improvements relating to Machines for the Grinding of Milling Cutters.
Inventor: SELLICKS GEORGE
Filed: 1907-03-22
Granted: 1908-03-05
Abstract: 6880. Sellicks, G. March 22. Saws, sharpening.-The machine is described as applied to the grinding of milling-cutters, but a special arrangement for grinding the type of cutters known as metalslitting saws, in which the rear edge of the teeth is ground,is alsodescribed. The work is mounted on a reciprocating table the motion of which operates a spring pawl to feed the cutter forward tooth by tooth, and also a vertically movable stop which engages the cutter teeth to hold it in position during the grinding operation. The stop which engages the back of the teeth is also fed forward at each revolution of the cutter to increase the depth of the cut. The cutter is mounted upon a spindle a, Figs. 1 and 5, carried by a slide. b, which is reciprocated by a right and left handed screw g, which may be driven through the pulley h or adjusted by a hand-wheel i. A standard e on the same bed d as the slide c, on which the slide b moves, carries a grinding-wheel f, which can be adjusted for wear. The cutter is fed forward tooth by tooth by a spring pawl k, Fig. 4, carried on an arm j, which is swung about the spindle a by a link l. one end of which is secured to the fixed part of the bed d. The rear edges of the teeth of the cutter are engaged during the grinding operation by a stop m carried by a stem n, which slides in a bracket o and is supported in its uppermost position by a spring p. The vertical, motion of the stop m is governed by a roller q, which engages a cam shaped projection s on a collar at the bottom of the stem n. The roller q is mounted on a sleeve r which is rocked about the spindle a by an arm and link attached to a stationary part of the machine similarly to the arm j. The roller q, which can move relatively to its support, is normally held in its uppermost position by a spring. As the table b moves away from the grinder, the sleeve r is rotated and the roller q moves over the top of the cam s, Fig. 7, and depresses the stem n and the stop m. When the roller e gets past the cam s, the stem is forced upward by the spring p, and the roller q on its return journey, as the table b moves towards the grinder, passes under the cam and is depressed in its mounting against the action of its spring, until it has passed the cam, when it is forced upward by the spring ready for the next movement. As the table moves away from the grinder, the tooth of the cutter 4, Fig. 4, compresses the spring pawl k, owing to the rotation of the arm j about the spindle a, until the stop m is withdrawn from engagement with the cutter teeth, when the spring pawl is allowed to act and turns the cutter through the space of one tooth. The stop m then re-engages the cutter through the space of one tooth. The stop m then re-engages the cutter, and any small further motion of the table merely serves to compress the pawl slightly. On the return journey of the table, the pawl slips idly over the teeth. In the special arrangement for grinding metal-slitting saws, the cutter is mounted on a bush 14, Fig. 8, on the spindle a. The bush is supported by a ring 15 enclosing a spiral spring 16, the ends. of which abut against a pin 18 on the ring 15, and a pin 19 on the plate 17 secured to the spindle a. As the cutter is fed forward by the spring-pawl arrangement described above, the ring 15 is rotated by frictional contact with the bush 14, and the spiral spring 16 is sufficiently compressed to impart to the cutter, during the return motion of the cutter-carrying slide, a slight return motion to carry the advanced tooth into contact with the stop m. The cutter is fed forward by the angular movement of the stop m. The bush 14 is provided with a projection 21, which engages an arm 22 at each revolution of the cutter. The consequent motion of the arm 22 operates levers 23; 24 and a ratchet 20 and the axis of the worm 10.