| 摘要 |
<p>A fabric feed for a sewing machine has a feed foot and a holddown foot that are vertically oppositely reciprocable between upper positions and lower fabric-engaging positions, and a continuously operating rotary drive with a rotating output whose rotary motion is transformed by an appropriate linkage into alternating reciprocation of the feed foot and the holddown foot. The feet are alternately engaged with and disengaged from fabric in the fabric-engaging position. On moving downwardly from their upper into their lower positions the feet are each first accelerated to a maximum speed reached when approximately midway between the upper and lower positions and thereafter are decelerated to an intermediate speed lying between zero and seven-tenths of the maximum speed reached when they attain the lower fabric-engaging position.</p> |
