Sewing mahine drive apparatus and method
AssigneeMitsubishi Denki Kabushiki Kaisha
InventorTakayuki Wakana
Life of this patent
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Abstract
A sewing machine apparatus driven by a motor, which is subject to velocity control on the basis of a detector for determining the rotary position and/or velocity of the motor output shaft. A controller is operative to control the speed of the motor in accordance with a velocity command value. A means for generating a holding force during a stop of the sewing machine ensures that the sewing needle does not provide unwanted movement. The holding force is changed when movement from the stop position is desired, as by changing the force in relation to the speed or amount of movement. This feature is particularly useful to reduce the load presented to an operator who wishes to manually change the machine position.
Claims21
A sewing machine drive apparatus for controllably driving a sewing machine comprising:
- an output shaft;
- drive means operable to move said output shaft at a controlled speed and to drive said sewing machine;
- detection means for detecting a movement corresponding to movement of said output shaft;
- control means for controlling the speed of said drive means, including a stop, according to velocity commands;
- holding force generation means for generating a holding force during a stop of said sewing machine;
- and
- holding force changing means responsive to said detection means for changing the holding force generated by said holding force generation means according to the movement of said drive means.
A method of controlling a sewing machine having a drive apparatus comprising a velocity controllable drive with an output shaft that is moveable to detectable rotary positions and at detectable velocity comprising:
- selectively providing a speed control for said drive apparatus according to a velocity command;
- selectively providing a holding force at a first level when said drive apparatus is stopped at a stop position;
- detecting movement corresponding to movement of said drive apparatus after said stop;
- determining whether said movement exceeds a predetermined value;
- and
- if said predetermined value is exceeded, changing said holding force.
Dependencies are inferred from the claim text.