Sewing machine provided with adjusting mechanism for adjusting pressing force applied to workpiece

A sewing machine comprising:

• a sewing machine motor;
• a needle bar having a lower end on which a sewing needle is mountable, the needle bar being configured to be driven by the sewing machine motor to move in an up-down direction;
• a needle plate having a plate upper surface, a needle hole, and an opening, the plate upper surface being an upper surface of the needle plate, the sewing needle being configured to pass through the needle hole;
• a feed dog configured to be driven by the sewing machine motor to move in the up-down direction through the opening to feed a sewing object placed on the needle plate, the feed dog having a feed dog upper end, the feed dog upper end being an upper end of the feed dog;
• a presser bar having a lower end on which a presser foot is mountable, the presser bar being configured to move in the up-down direction in synchronization with movement of the feed dog;
• a presser bar holder fixed to the presser bar;
• an adjustment portion configured to move in the up-down direction;
• a presser spring configured to urge the presser bar downward via the adjustment portion and the presser bar holder;
• a restriction portion configured to restrict transmission of urging force from the presser spring to the presser bar when the restriction portion contacts with the adjustment portion;
• and
• a change member having a first member, and a second member supported to be movable with respect to the first member, the change member being configured to change a position of the restriction portion in the up-down direction according to a distance between the first member and the second member,
• wherein, in a first period in which the feed dog upper end is above the plate upper surface and the adjustment portion is spaced apart from the restriction portion, the adjustment portion contacts with the presser bar holder to cause the urging force of the presser spring to be transmitted to the presser bar, and
• wherein, in a second period in which the feed dog upper end is beneath the plate upper surface and the adjustment portion contacts with the restriction portion, the adjustment portion is spaced apart from the presser bar holder in the up-down direction to prevent the urging force of the presser spring from being transmitted to the presser bar.