JPS5846987A - Stitch adjusting apparatus in main stitch seweing machine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Technical Field) The present invention relates to a stitch adjustment device (Kgkl) in a single stitch ξ-thin.
In particular, the present invention relates to a stitch adjustment device for a lockstitch sewing machine, which allows the adjustment of the stitches to be optimized depending on the type of stitch.

(Prior Art) Conventionally, stitch adjustment in a lockstitch sewing machine is generally performed by easily adjusting needle thread tension.

That is, the upper thread tension is adjusted by operating the operation dial of the upper thread tension device, but in rare cases, the lower thread tension is adjusted by adjusting the adjustment spring of the bobbin case that houses the lower thread. However, since adjusting the bobbin thread tension is troublesome, it has not been done many times.

For this reason, it has not been possible to obtain optimal stitches for various types of stitching in lockstitch sewing machines.

For example, as shown in Figure 1, in straight stitching, the intersection (P) of the upper thread (1) and lower thread (2) may intersect at the point #1 of the fabric (3) at the center. However, as shown in Figure 2, when sewing a zigzag stitch, the upper thread (1)
) is the point in the middle of the thick central part.The lower thread Q) can be seen from the upper surface of the fabric (33), so there is no mtL<, but rather, as shown in Figure 3, the intersection (g) In this way, in a lockstitch sewing machine, the intersection point (3) of the upper thread (1) and lower thread (2) is moved by the 0 stitch type. Therefore, it is desirable to adjust the needle thread tension and bobbin thread tension each time, but this work, especially adjusting the bobbin thread tension, is troublesome and very tedious for the operator. (Purpose) The present invention has been made in order to eliminate the drawbacks of the prior art as described above. By making it possible to adjust the amount of bobbin thread pulled out near the top dead center of a certain thread take-up in conjunction with the operation of the operating member, it is possible to obtain the most desirable stitches depending on the type of sewing. Another purpose is to automatically obtain the most desirable stitch for other stitches by simply making adjustments in advance to obtain the most desirable stitch for a particular stitch. (Solution Means) In short, the present invention provides a lockstitch sewing machine equipped with a bobbin thread pull-out member that pulls out the bobbin thread every 0 stitches (≦mechanism). A lower thread draw-out adjustment device that operates a lower thread control member that controls the amount of lower thread pulled out in conjunction with an operating member, and one of a pair of thread tension springs that applies upper thread tension to a pair of thread tension discs is operated as described above. The present invention is characterized in that it is provided with an upper thread tension adjusting device which can be switched between active and inactive state 1aK in conjunction with the member.

(IK Example) The present invention will be explained below based on the example shown in the drawings. In Figs. 4 to 6, the device (5) according to the present invention is a sewing pattern selection device (6), an upper thread The sewing machine frame (wJ not shown) is equipped with an adjustment device (η) and a bobbin thread drawer adjustment device (8).
11 attached cam shaft wheel, said cam shaft K. A gear mechanism (2) interlocks with the upper shaft (b) which is rotatably supported on the sewing machine frame.
a plurality of pattern cams (2) rotatably inserted through the
Feed screw shaft 64KII arranged parallel to camshaft (2)
An amplitude follower (
2) and a pattern selection dial (2) which is an example of an operating member fixed to a dial shaft (not shown) rotatably supported on the sewing machine frame.
) is rotated, the claws *@ fixed to the dial shaft and feed screw shaft tHK, respectively, and the belt (
The feed screw shaft O rotates via the amplitude follower (2
) moves in the axial direction to selectively engage the pattern cam (2)K. The oscillating motion of the amplitude follower (2) imparts oscillating motion to the needle bar (not shown) via the amplitude rond (2).

The needle thread tension adjustment device (7) includes a thread tension mechanism (2) attached to a thread tension shaft 94 fixed to the sewing machine frame, and a fixed shaft 94 fixed to the sewing machine frame parallel to the thread tension shaft ring. a pair of thread tension discs (2) fitted into the holder, a thread tension lever whose middle portion is pivotally connected to the sewing machine frame by a pivot V4; (2
).

The thread tension mechanism is located at the upper part K1 of the threaded part (20a) of the thread tension shaft.
The circular thread tension dial (A), the thread tension ring (31) fitted into the lower part of the threaded part (20 m) of the thread tension shaft and loosely fitted into the thread tension lever, and the thread tension lever. The first thread wound around the thread tension shaft ring between ■ and the thread tension dial ■
The thread tension shaft HK:! is located between the thread tension spring (32), the keynote 4 dial (2), and the thread tension ring (31). equipped#
There are eleven thread tension springs (32) and a second thread tension spring (33) having a smaller spring constant. Further, the thread tension lever @ is configured to swing in the direction of arrow A about the pivot axis Wt by the thread loosening lever (35). The fixed first adjusting cam (3g) K is press-fitted by a spring (not shown), and the other end (25b) is loosely fitted into the thread tension shaft below the thread tension ring (31).

The bobbin thread pull-out adjusting device (8) includes a feed tooth (3B) which is an example of a bobbin thread pull-out member, a bobbin thread control member (39), and an adjustment mechanism (40). ss) is fixed to a feed table (45) K whose one end is pivotally connected to a horizontal feed shaft (43) which is swingably supported on the sewing machine frame. A bobbin thread pull-out portion (38a) is formed in the thread feed tooth (381).One end of the bobbin thread control member (39) is pivotally attached to the machine frame by a pivot (46), and the other end is pivoted to the thread feed tooth (381). ] The lower thread pull-out portion t38a)ic of the tooth (38) is disposed below so as to be opposed to it.

The adjustment mechanism (40) is an Igl adjustment lever (47), an irises 2
A first adjustment lever (48), a connecting link (49), and an adjustment cam (50) of the lever 2 are provided.
47) has an intermediate portion pivotally connected to the sewing machine frame by a pivot (51), and a follower (47m) formed at one end engages with the back surface of the bobbin thread control member (39). The adjusting lever (48) of the horse 2 has its intermediate portion pivoted to the sewing machine frame by a pivot (52), and is press-fitted by a spring K (not shown) of the adjusting cam (50) of the irises 2 having one end. Connecting link (
49) are pivotally connected to the other end of the first adjustment lever (47) and the other end of the second adjustment lever C48) by means of a pin (s5) K.

The horizontal rotary hook (56) indicated by the broken line in Figure 4 is the feed tooth (3B).
The lower shaft (57) is rotatably supported on the sewing machine frame and can be rotated via a gear mechanism (58).

The present invention is constructed as described above, and its operation will be explained below. As shown in Fig. 6, the bobbin thread pull-out part (38m) is formed in a part of the fitting tooth (3B).
The bobbin thread (2) is pulled out by the bobbin thread pull-out section moving as shown by the broken lines in Fig. P#17 and Fig. drawer and vB
In the same figure while tightening, (75) is a known throat plate.

In general, the relationship between the needle thread tension at the intersection of the stitches of the needle thread (1) and the bobbin thread (2) is shown in Figure 9, where the vertical axis is the Ki1th intersection point (G) and the horizontal axis is the needle thread tension. As shown by taking the tension,
For example, if U is the upper surface of the upper fabric, M is the mating surface of the upper and lower fabrics, and L is the lower surface of the lower fabric, the curve when the upper and lower thread tensions are low is E.
], the curve when the upper and lower thread tensions are high is G. As can be seen from the figure, at low upper thread tension shown by curve E, F
It is shown that a proper intersection can be obtained at point F, and at a high needle thread tension shown by curve G, a proper intersection can be obtained at point F. Also curve 1. G is the pull-out amount of the bobbin thread (2) instead of the bobbin thread tension, that is, the stroke Δ of the bobbin thread pull-out part (3B&) in FIG.
The stroke Δ can also be determined analogously by
As a result of experiments, it has become clear that the smaller the number of threads, that is, the smaller the one-output amount, the higher the bobbin thread tension is applied and the tolerance is improved.

In the present invention, even if the snoring stroke Δ is the same, by changing the position of the bobbin thread control member (39), the amount of bobbin thread withdrawal can be substantially changed. That is, when the bobbin thread control member (39) is at the top dead center as shown in FIG. However, as shown in FIG.
By changing the position of 9), the amount of pull-out of the bobbin thread Q) near the top dead center of the thread take-up changes, thereby substantially changing the thread tightening effect of the bobbin thread.

In Fig. 4, when the pattern selection dial (2) is rotated to select an appropriate sewing pattern, the feed screw shaft 04 is rotated via the ratchet wheel (B) and the belt ■, and the amplitude follower (2) is rotated.
) moves in the axial direction and selectively engages the pattern element 50, imparting an oscillating motion to the needle bar via the amplitude rod. 11 at the same time
The 12 adjustment levers (48) swing via the follower (4k), and the first adjustment lever (47) is connected to the connecting link (49).
When it swings around the pivot (51) through t7, the control member (39) moves around the pivot (46) and stops at a fixed position by the follower (47a)K of the 1011th node lever C47). As a result, as explained in FIGS. 7 and 8, the amount of pull-out of one bobbin thread (2) changes, and the thread tightening effect of the bobbin thread substantially changes. On the other hand, the adjusting member (2) 2k) Axis-
When the thread tension ring (31) is moved upward, the spring pressure applied to the thread tension lever w4 is Tension applied to the upper thread (1) held between only the thread tension spring (32) and the pair of thread tension discs,
That is, the needle thread tension changes. When a sewing pattern is selected by appropriately rotating the pattern selection dial (2) in this way, the shapes of the first adjustment cam (36) and the irises 2 adjustment cam (50) are set according to the type of stitch. te><Koto K Yoshi, needle thread<1
) and the bobbin thread (2) can be combined so that the position of the O intersection (b) is the most appropriate, and an ideal stitch can always be obtained.

Then, set the thread tension dial (2) for a particular stitch.
The most desirable stitches can be obtained by rotating the thread tension spring (33) (11.2) automatically for other stitches.

No. 10511 shows a second embodiment of the present invention, in which a vertical shaft (60) is swingably supported on an electric machine frame parallel to a horizontal transport shaft (43).

The adjustment cam (61) is slidably inserted into the vertical feed shaft (60), and is inserted into the spiral groove C5ta formed on the outer circumferential surface.
A bottle (62) K is inserted into the shaft (60) of the upper and lower passageways. The adjustable cam (61) has a cam surface (alb).
is formed], and the lower surface of a bobbin thread control member (39) formed with (3 mm) corresponding to the bobbin thread pull-out portion (38a) K of the first embodiment is in contact with the cam surface); Adjustment cam (61)
A pin (65) of nine swing links (64), which is pivotally connected to the sewing machine frame by means of a pivot (6B) K, is fitted into the annular groove (610) formed in K. Then, the swing link is connected to the rod. (66) To change the movement phase of the K yam bobbin thread 1g1101S material (39) by making it swing in conjunction with the operating member 04 via f, and to change the bobbin thread pull-out amount and bobbin thread pull-out phase near the top dead center of the thread take-up. Since the handle and other parts are the same as those in the first embodiment, reference numerals are attached to the drawings and explanations thereof will be omitted.

FIG. 11 shows a third embodiment of the present invention, in which the cam surface (61b) of the adjusting cam (61) (which is different from the second embodiment) has a conical shape; Since it is the same as the second embodiment, reference numerals are attached to the drawings and explanation thereof will be omitted.

FIG. 12 shows a fourth embodiment of the present invention, in which the needle bar amplitude and feed are controlled by a needle motor (701 (71)) driven by signals from a microcomputer. The control motor (7) is an example of an operating member that drives the first adjustment lever (47) of the first embodiment by a signal stored in a microcomputer.
2) Therefore, the pulse motors (70) and (71) are designed so that the lower thread is drawn out properly for each stitch in one cycle in synchronization with the pulse motors (70) and (71). The rest is the same as the first embodiment, so the reference numerals are attached to the drawings and the explanation is omitted. (Effects) Since the present invention is constructed and operates as described above, there are Since the amount of bobbin thread pulled out near the top dead center of a certain thread take-up can be adjusted in conjunction with the operation of the operating member, the most desirable stitch can be obtained depending on the type of sewing. By simply making adjustments in advance so that the most desirable stitches can be obtained for a particular stitch, there is an effect that the most desirable stitches can be automatically obtained for other stitches as well.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing the intersecting state of straight stitches in a lockstitch sewing machine, Figs. 2 and 3 are perspective views showing intersecting states of zigzag stitches in the lockstitch sewing machine, and Figs.
The figures show an embodiment of the chain according to the present invention. Fig. 4 is a perspective view showing the main parts of the device related to the invention, Fig. 5 is a longitudinal cross-sectional view showing the thread tension mechanism, and Fig. 6 is a feeder. FIGS. 7 and 8 are a perspective view showing the relationship between the lower thread control member and the lower thread control member; Figure 9 is a diagram showing the relationship between the stitch crossing position and needle thread tension, and Figures 10, 11, and 12 are diagrams of the second embodiment, the third embodiment, and the fourth embodiment of the present invention, respectively. It is a perspective view showing the main parts of the bobbin thread pull-out adjustment device. In the figure, (2) is the bobbin thread, (7) is the needle thread tension adjustment device, and (8) is the bobbin thread tension adjustment device.
) is a bobbin thread drawer adjustment device, (2) is a pattern selection dial which is an example of an operating member, the ring is a thread tension plate, (32) (33)
(38) is a feed tooth which is an example of a bobbin thread pull-out member, (39) is a bobbin thread control member, and (56) is a horizontal shuttle which is a part of the hook mechanism. Patent applicant Janome Sewing Machine Industry Co., Ltd. Inventor
Susumu Hanyu 5th plan Figure 9 Figure 6 Figure 7 Figure 8

Claims (1)

[Claims] In a lockstitch sewing machine equipped with a bobbin thread pull-out member on the bobbin thread side that pulls out the bobbin thread for each stitch, the bobbin thread control member that controls the amount of bobbin thread pulled out by the bobbin thread pull-out member is linked to the operating member. A lower thread pull-out adjustment device that is operated by the operation member and one of a pair of thread tension springs that apply upper thread tension to a pair of thread tension discs are switched between an activated state and an inactive state i1 in conjunction with the operating member. 1. A stitch adjustment device for a lockstitch sewing machine, characterized in that a needle thread tension adjustment device is provided.