Sewing machine
AssigneeJanome Sewing Machine Co., Ltd.
InventorMakoto Nakajima
Life of this patent
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Abstract
The present invention provides a sewing machine that can actuary detect a physical amount of a movement of a fabric without depending on an estimated value. Thus, thread tension can be precisely adjusted. A sewing machine 1 includes a spherical body 22a exposed partly from a needle plate 2. The spherical body 22a is rotated following a feed of a fabric 100. The rotation of the spherical body 22a is detected by rotary encoders 22c, 22d. A physical amount of the movement of the fabric 100 is calculated based on a detection result of the rotary encoders 22c, 22d. The physical amount of the movement of the fabric 100 is, for example, a moving amount and a moving speed.
Claims7
A sewing machine for forming stitches on a fabric by passing a needle through the fabric to interlace an upper thread and a lower thread with each other, comprising:
- a needle plate on which the fabric is placed;
- a spherical body that is exposed partly from the needle plate, the spherical body being rotated by a friction force applied between the fabric and the spherical body;
- an encoder that detects a rotation of the spherical body;
- a calculator that calculates a physical amount of a movement of the fabric based on a detection result of the encoder;
- a first motor;
- an upper shaft that is rotated by the first motor;
- a lower shaft that is rotated in conjunction with the upper shaft;
- a thread take-up lever that receives a driving force from the first motor via the upper shaft;
- a needle bar that receives the driving force from the first motor via the upper shaft;
- a rotary shuttle that receives the driving force from the first motor via the lower shaft;
- a second motor that is different from the first motor;
- a lower thread feeder that is driven by receiving a driving force from the second motor to supply the lower thread according to a timing and an amount of driving the second motor;
- and
- a controller that drives the second motor based on the physical amount of the movement of the fabric to control a timing and an amount of supplying the lower thread of the lower thread feeder, wherein
- the lower thread feeder and the thread take-up lever are separately controlled.
Dependencies are inferred from the claim text.