JPS62123782U - - Google Patents

Description

[Brief explanation of the drawing]

FIG. 1 is a schematic front view showing the sewing machine of the embodiment with the main control circuit added, FIG. 2 is a partially enlarged perspective view of the sewing machine, and FIG. 3 is an enlarged cross-sectional view of the thread tension regulator.
FIG. 4 is a block diagram showing the control circuit of the sewing machine of this embodiment, and FIG. 5 is a graph showing the relationship between the operating curves of the thread take-up, feed dog, etc., and the thread release and thread clamping signals.
6a and 6b are schematic side views showing the magnetization states of the electromagnets corresponding to yarn release and thread clamping; FIG. 7 is a flowchart mainly showing the yarn releasing and thread clamping operations;
FIG. 8 is a flowchart showing a subroutine for setting the thread release period, and FIGS. 9 and 10 a and b.
FIG. 2 is a schematic side view of a thread tension device showing another embodiment of this invention. 14... Needle, 15... Needle thread bobbin as a needle thread supply source, 19... Thread tension device, 20... Balance, 21
... Thread ring catcher, 32 ... First electromagnet, 33...
...Second electromagnet, 36...Core part as magnetization part, 37...Yoke part as thread clamp holding part, 39...
... Coil, 40 ... Support shaft, 41 ... Thread tension plate, 5
1...CPU constituting the control means.

Claims (1)

[Claims for Utility Model Registration] 1. Needle thread T1 and bobbin thread T2 are separated by feeding the fabric while picking up the needle thread loop that has passed along the circumference of the inner hook of thread loop catcher 21 with thread take-up 20. In a sewing machine that forms stitches by tying knots in cloth, the needle is movably supported between the needle 14 and the needle thread supply source 15 on a support shaft 40 that extends in a direction intersecting the thread passing direction, and is made of a permanent magnet. It includes a thread tension plate 41, a thread clamping member 37 for clamping the needle thread T1 between the thread tension plate 41, a coil 39, and a magnetized portion 36 that is magnetized by energization of the coil 39. , the coil 39
By selectively setting the energized state and non-energized state of the coil 39, or by changing the direction of the current flowing through the coil 39, the magnetized state of the magnetized portion 36 is changed, and the thread tension plate 41 is moved in the thread clamping direction or Move the thread tension plate 41 in the thread release direction.
electromagnets 32 and 33 disposed close to at least the thread clamp holding side of the thread tension plate 41 in order to clamp and release the needle thread T1 between the thread tension plate 41 and the thread clamp holding body 37; the electromagnet 32,
3. A thread tension device for a sewing machine, characterized in that a control means 51 for controlling the switching timing of the magnetization state of the thread tension device 33 is provided. 2. The control means 51 releases the needle thread T1 from being held by the thread tension plate 41 and the thread holding member 37 during a period in which the needle thread T1 is paid out from the thread supply source 15 side for stitch formation. At the same time, during other periods, the electromagnet 32,
3. The thread tension device for a sewing machine according to claim 1, wherein the thread tension device is adapted to control the switching timing of the magnetization state of the sewing machine.