| 摘要 |
PROBLEM TO BE SOLVED: To keep a fabric feed per revolution of a lower shaft constant. SOLUTION: A fabric feeding apparatus 7 is equipped with a transmission mechanism 30 and a feed dog 20. The transmission mechanism 30 is coupled to the lower shaft 10 which is rotated by a sewing machine motor 47, and transmits the rotational motion of the lower shaft 10 by changing the rotational motion thereof into the elliptic or circular motion of the feed dog 20. A square piece 22 is coupled to the transmission mechanism 30, and the angle of gradient of the square piece 22 is changed by the power of a motor 28, so that the orbit of the feed dog 20 can be changed and so that a fabric feeding pitch can be changed. The rotational speed of the motor 47 is detected by a rotational-speed detector 41 of the apparatus 7; and a control device 8 of the apparatus 7 controls the level of a holding current which flows into the motor 28 in accordance with the rotational speed of the motor 47, so that a force, which acts on the square piece 22 from the motor 47, and an inertia force, which acts on the square piece 22 from the transmission mechanism 30, can be brought into balance, so that the fabric feeding pitch can be kept constant. COPYRIGHT: (C)2004,JPO
|
