JPH02106183U - - Google Patents

Description

[Brief explanation of the drawing]

1 to 15 show a first embodiment of the present invention, in which FIG. 1 is a plan view of the main parts of the sewing machine including the thread cutting device, FIG. 2 is a left side view of FIG. 1, and FIG. Fig. 3 is a plan view of the moving knife, Fig. 4 is a plan view showing the moving knife together with its rotating force transmission mechanism, Fig. 5 is a sectional view of the sleeve fitted onto the moving knife, and Figs. 6 to 9. 10 is a perspective view of the main parts showing the movement of the thread cutting mechanism and picker in relation to the upper and lower threads, FIG. 10 is a timing chart of the thread cutting device, and FIGS. A plan view showing the positional relationship between the movable knife and each thread at various rotational positions when cutting both bobbin threads, and FIG. 15 is a plane view corresponding to FIG. 14 when cutting only the fabric side needle thread. Figures, Figures 16-1
FIG. 9 shows the second embodiment of the present invention, and the 16th embodiment
The figure is a plan view of the main parts of the sewing machine including the thread cutting device, FIG. 17 is a left side view of FIG. 16, and FIG.
19 is a schematic front view of FIG. 16, which mainly shows the moving mechanism of the moving knife. be. 10... Thread cutting mechanism, 13... Throat plate, 30...
Hook, 34... Needle hole, 38... Fixed blade, 44... Moving knife, 44a... Cutting blade, 44b... Locking groove (needle side needle thread locking part), 44c... Guide surface, 44d... …
End portion (lower thread locking portion), 60, 93... moving mechanism,
T1... Upper thread, T2... Lower thread, T1a... Needle side upper thread, T1b... Fabric side upper thread, P... Lower thread cutting position,
P', P''...Bobbin thread cutting position.

Claims (1)

[Scope of utility model registration request] In a sewing machine that performs sewing using a bobbin thread sent out from a hook provided below a needle hole in the throat plate, and an upper thread fed out from a needle that moves up and down toward the hook through the needle hole, Below is a movable knife that can reciprocate between a standby position and a swinging position in a plane substantially parallel to the throat plate, and a fixed knife that cooperates with the movable knife to cut the thread in a predetermined manner. the movable knife has a thread dividing end and a needle-side needle thread locking portion connected thereto on the front side in the direction of rotation toward the swinging position, and a cutting blade on the rear side; When moving from the standby position to the swinging position, the needle-side needle thread is separated into the needle-side needle-thread locking portion side and the fabric-side needle thread is separated into the cutting blade side, and when the movable knife is rotated, a lower thread cutting position where the center of rotation is located at a point where the lower thread exists within the rotating plane, which is located outside the rotation locus of the thread dividing end and inside the locus of the radially outer end of the cutting blade; The lower thread exit point is movable to a lower thread non-cutting position located outside the locus of the radially outer end of the cutting blade, and when the center position is at the lower thread cutting position, the lower thread is moved to the standby position. It is characterized in that it is configured to be capable of cutting both the upper thread on the fabric side and the lower thread in cooperation with the fixed blade when the blade is rotated, and to cut only the upper thread on the fabric side when the lower thread is in the non-cutting position. Thread cutting device for sewing machines.