| 摘要 |
<p>A needle bar drive apparatus for a sewing machine includes a dedicated drive source (16) for driving a needle bar (3) of the sewing machine to move up and down. When a sewing operation is to be performed, a control section (160) controls the drive source to cause the needle bar to move up and down within a predetermined stroke range, but, when no sewing operation is to be performed, the control section controls the drive source to cause the needle bar to retreat to a predetermined evacuation position set above a top dead center in the predetermined stroke range. The control section is also capable of varying a timewise pattern of the upward and downward movement of the needle bar within the predetermined stroke range. Thus, it is possible to secure an increased space between the lower end of the needle bar and the upper surface of a sewing machine table (6) during a non-sewing period while limiting the stroke of the needle bar to a necessary minimum during a sewing period. Also, timing for driving the needle bar can be varied freely.</p> |
