| 摘要 |
A control assembly for varying the transmission ratio between a sewing machine driving shaft eccentric for feed dog transverse movement, and thus the feed and stitch widths, of a sewing machine which includes an oscillating lever mounted for oscillation adjacent to the feed dog and connected to it to move it backwardly and forwardly and an eccentric drive acting on the feed dog to move it upwardly and downwardly. The control assembly includes a push rod having one end connected to the oscillating lever to oscillate it and an opposite end having a pin thereon which is confined for movement in an oblong slot of a link which is articulated at its opposite end to one arm of a double armed lever, the other arm of which is engaged by the driving shaft eccentric to oscillate it. The pin carries a sliding block which is engaged in a sliding block guide and they are both made of a plastic having a sliding surface at their engagement surfaces. The guide is displaced in order to vary the oscillation of the feed dog in transverse directions. |
