| 摘要 |
PURPOSE:To produce variable rackes through grinding work with high productivity by combining the rotary movement generated by the engagement of a master rack and reciprocating movement of a cutting tool and the relative shift of the master rack and a worked material. CONSTITUTION:A part of a master rack 13 is protruded on the front surface of a shifting base 1, and the teeth having a fixed gear ratio is formed on the protruded part. The rack 13 and a cutting tool 17 are engaged, so the tool 7 is provided with rotary movement by the rack 13 during reciprocating movement. As the left end part of the cam surface of a cam plate 27 has the curvature convex upward, the relative shift speed of this rack 13 for the shift base 11 decreases gradually accompanied with the shift of the shift base 11, and the teeth having the equal pitch to the rack 13 is formed. As the working process proceeds, the teeth having the gradually varying pitch namely variable racks are manufactured in high productivity through a gear-ratio changing mechanism. |
