Abstract: A sewing apparatus is provided with an X-Y unit 4 for horizontally moving a cassette in relation to a sewing machine 3, memory 23 for holding sewing data for driving the X-Y unit 4 in accordance with a sewing pattern and feeding data for feeding only the cassette without entailing stitching action, a drill 10 for grooving a slot in the cassette, a vertical drive mechanism 18 for vertically moving the drill 10, and a CPU 22. The drill 10 is moved downward while rotating, and the X-Y unit 4 is actuated on the basis of the sewing data to form the slot. After the drill 10 has become deactivated and moved upwards, the cassette is fed on the basis of the feeding data. Since the CPU 22 executes the rotation and downward movement of the drill 10 at the time of grooving and the upward movement and interruption of rotation of the drill 10 at the time of feeding, switching operation required to rotate, move downward, move upward and to stop the drill 10 becomes unnecessary.

Abstract: A residual bobbin thread amount detection apparatus for a sewing machine which includes a hook rotating in association with a main shaft of the sewing machine and a bobbin rotatably mounted on the hook. A first detector detects the rotation speed of the main shaft and a second detector detects the rotation speed of the bobbin. A comparator responsive to the second detector generates a signal when the rotation speed of the bobbin exceeds a predetermined value, whereby a controller operates an alarm.

Abstract: A movement control apparatus for a sewing machine to automatically control movement initiating timing corresponding to various sewing machine speeds.

Abstract: An input device for an electronically controlled sewing machine is effective for inputting stitch patterns which are partially prohibited from scaling up or scaling down. A control circuit is signalled that points of a stitching pattern are not to be scaled. A check bit added to the coordinate value of prohibited-scaling stitch points flags the scaling prohibition condition.

Abstract: A sewing machine having a work holder with a crank member in which a computing device is provided for computing coordinate values in accordance with the configuration of the work holder with the crank member and particularly, designed to convert coordinate values of a reference sewing pattern into coordinate values with the center of the crank member on the work holder with the crank member as the origin when the sewing pattern is enlarged or reduced in scale. When work holder with the crank member is returned to the sewing start point on the sewing pattern, the work holder with the crank member is returned in the direction of the X axis or Y axis depending upon the positional relationship between the existing position of the work holder with the crank member and a reference value.