| 主权项 |
1. A sewing machine comprising:
a needle rod on which a needle is mountable and configured to be reciprocated vertically; a pair of tension discs configured to sandwich an upper thread therebetween; a feed mechanism configured to transport a sewing object in a vertical direction; a reciprocating mechanism configured to reciprocate the needle rod laterally with respect to the vertical direction; an upper thread tension adjusting mechanism configured to adjust the tension discs by switching between an open state in which the tension of the upper thread is released, and a restored state in which the tension is restored; a feed amount adjusting mechanism configured to adjust a feed amount of the feed mechanism; a stitch width adjusting mechanism configured to adjust a stitch width of the reciprocating mechanism; and a control apparatus configured to control the upper thread tension adjusting mechanism, the feed amount adjusting mechanism, and/or the stitch width adjusting mechanism, wherein a common adjusting mechanism, which is one of the feed amount adjusting mechanism and the stitch width adjusting mechanism, includes:
a motor;an adjusting mechanism body which is a tooth-missing gear whose teeth are partially missing and/or a cam and configured to be driven by the motor; anda variation amount adjusting unit configured to change the variation amount, which is the feed amount of the feed mechanism or the stitch width of the reciprocating mechanism within a first range which is part of a movable range of the adjusting mechanism body by either one of a driven gear that engages the teeth of the tooth-missing gear or a driven member pushed by a cam surface of the cam; the upper thread tension adjusting mechanism includes:
a thread loosening portion engaging the tooth-missing gear or pressed by the cam surface within a second range deviated from the first range in the adjusting mechanism body; andan upper thread tension adjusting unit configured to switch the tension discs from the restored state to the open state in conjunction with the thread loosening portion, and the control apparatus performs an opening action that switches the tension discs to the open state by changing the adjusting mechanism body in the second range when the common adjusting mechanism does not have to perform an adjustment of the variation amount, and when the tension discs need to be opened. |
