Programmed pressure foot positioning for control means sewing machine

A pressure foot unit for a sewing machine comprising:

• a pressure foot member supported by a body of the sewing machine in an elevatable manner and located adjacent to a sewing needle;
• a plurality of spherical means rotatably mounted at different positions within the pressure foot member, each partly exposed through the lower surface of the pressure foot member;
• an elastic member mounted on the pressure foot member for urging each spherical member downward;
• drive means for driving the pressure foot member for elevating motion;
• reference position detecting means for detecting that the pressure foot member is located at a given position;
• and
• positioning control means for energizing the drive means to position the pressure foot member as referenced to a position detected by the detecting means, to position the pressure foot member at a first position during an elevating motion of the needle, to position the pressure foot member at a third position which is substantially by the order of thickness of a fabric higher than the first position during a movement of the fabric, and to position the pressure foot member at a second position higher than the third position in response to a given release command.