Abstract: A method of forming a stitch pattern is disclosed in which at least two closely spaced or coincident end stitches are present. The overall pattern is divided into overlapping block sections. In one block, a first group of stitches is formed followed by a second group of stitches being formed in an adjacent block. The number of stitches between closely spaced or coincident stitches that results is reduced. Therefore the accumulated error of fabric feeding pitches and the distance between the two end stitches is reduced resulting in a more precisely constructed overall pattern.

Abstract: During stitching a pattern, there is often issued a designation to change the pattern under forming to the other. In such a case total load on a fabric feed control motor and a needle amplitude control motor is temporarily increased. A microcomputer which controls driving of these motors, discriminates the new designation and rotating phase of the sewing machine and drives the fabric feed control motor by means of specific data by mean value of the maximum and the minimum fabric feed control data, instead of the fabric feed control data which is first read out next to said designation.

Abstract: An assembly for adjustment of lower thread tension for a sewing machine having a loop taker and a bobbin carrier which is held by the loop taker and carries a bobbin loaded with the lower thread. The assembly comprises a base plate and a resilient member, one end of which is connected to the base plate. A tension is given to the lower thread while the thread is passed between the base plate and the resilient member. A substantially L-shaped presser element having an upper vertical and a lower horizontal portion is provided for the assembly and is turnably attached to an inner wall of the bobbin carrier. The vertical portion of the presser element is adapted to press a free end of the resilient member against the base plate. A permanent magnet or electromagnet acts on the horizontal portion of the presser element without contact thereto.

Abstract: A stitch-length correcting sewing machine and a stitch-length measuring presser foot assembly used therein are disclosed. The sewing machine and presser foot assembly enables stitches of a predetermined length to be sewn, without the necessity of stitching a trial stitch on a piece of fabric and adjusting the sewing machine to compensate for variations in fabric type and thickness. The presser foot assembly utilizes a presser foot which is detachably securable to a presser bar. A movable presser frame slides on the presser foot as fabric is fed. A potentiometer is fixed to the presser foot and responds to sliding of the presser frame so as to enable distance moved by the presser frame to be ascertained by detecting the resistance of the potentiometer. The presser foot assembly can be used as a fabric sensor responsive to fabric motion in an electronic sewing machine.

Abstract: When a pulse motor in an electronic sewing machine is to be subjected to a heavy load, the pulse motor is operated at a slower speed in order to cause the pulse motor to operate at a rate in which it has a maximum torque output. For lesser load conditions, pulse motor speed is allowed to increase. Speed control of the pulse motor follows a generally trapezoidal curve, which curve includes a speed-up section and a slow-down section, and may include a flat section. That portion of the generally trapezoidal curve along which motor speed follows is determined by the distance which the pulse motor is required to move.