US3515083A - Device for free thread passage in the sewing machine - Google Patents

Description

June 2, 1970 KOICHI TOMONO ETAL 3,515,033

DEVICE FOR FREE THREAD PASSAGE IN THE SEWING MACHINE I Filed Aug. 26, 1968 4 Sheets-Sheet l Fi .1. 32 311718\59 58 30 36 39 11 57 1 6 26 fi\// Kmcm TOMONO,

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DEVICE FOR FREE THREAD PASSAGE IN THE SEWING MACHINE Filed Aug. 26, 1968 4 Sheets-Sheet 8 Fig-6.

KOICHI ToNmNO. YOSHIMASA OMAHA am MILHI TAKEHAM INVENTOR$ BYIIJMUILYIIL (M.

ATTORNEY;

June 1970 KOICHI TOMONO ETAL 3,515,

DEVICE FOR FREE THREAD PASSAGE IN THE SEWING MACHINE Filed Aug. 26, 1968 4 Sheets-Sheet 4 United States Patent 3,515,083 DEVICE FOR FREE THREAD PASSAGE IN THE SEWING MACHINE Koichi Tomono, Toyonaka-shi, Yoshimasa Okada, Suitashi, and Koichi Takehama, Ibaraki-shi, Japan, assignors to Soryu Mishiu Seizo Kabushiki Kaisha, also known as The Soryu Sewing Machine Mfg. Co., Ltd., Ibaraki-shi,

Japan Filed Aug. 26, 1968, Ser. No. 755,181 Claims priority, application Japan, Apr. 16, 1968, 43/ 25,691 Int. Cl. Db 57/10 US. Cl. 112-232 5 Claims ABSTRACT OF THE DISCLOSURE A bobbin thread case is mounted in a stationary inner shuttle which is positioned in a rotary outer shuttle. The outer shuttle is rotated by a shaft which also has a cam thereon. The inner shuttle is prevented from rotating by a drag which catches an arm of the bobbin thread case and a protrusion of the inner shuttle. A reverse lever is operated by the cam to temporarily rotate the inner shuttle reverse to the direction of rotation of the outer shuttle.

This invention relates to a device for free thread passage in a sewing machine equipped with a full circularly moving rotary shuttle, more particularly to a device for free passage of thread which facilitates the passage of the upper thread as it is drawn upward round the outside of the inner shuttle. v

In the sewing machine equipped with a full rotatory shuttle, the outer shuttle constantly makes a continuous rotation in one direction, a drag provided on the lower surface of the sewing machine bed being engaged with a notch of the inner shuttle from the necessity of preventing the rotation of the said inner shuttle as well as the bobbin thread case.fitted thereinside. The notch of the inner shuttle being in constant contact with the drag, the upper thread which travels upward round the outside of the inner shuttle is subjected to considerable resistance as it is necessary for the said thread to pass through the contacting parts of the notch of the inner shuttle and the drag by forcing the said parts open.

The foregoing device is defective in that irregular tightening is apt to occur to the upper thread, and a noise is produced by the collision between the drag and the notch which are forced open by the upper thread and then restored after the passage of the said thread.

The first object of the invention is to obtain regular stitches by means of uniform thread tightening by removing the foregoing resistance arising at the time of the passage of the upper thread, as well as to silence the noise which arises at the time of passage of the thread.

The second object of the invention is to facilitate the adjustment of the timing of the shuttle rotation and that of the reverse lever which makes the passage of the thread easier.

The third object of the invention is to enable to use for this purpose the bobbin and bobbin thread case for the conventional home sewing machine equipped with a semicircularly moving rotatory shuttle without any adapter whatsoever.

The fourth object of the invention is to stabilize the sustaining state of the lower thread whereby to render the thread arranging board of the outer shuttle useless.

The fifth object of the invention is to facilitate the passage of the thread even when the device for free thread passage fails to function satisfactorily.

The sixth object of the invention is to so arrange that the thread or the like is hardly wedged between the inner Patented June 2, 1970 and outer shuttles as well as to make it easy to remove the thread or the like even when wedged.

The seventh object of the invention is to minimize the risk of breakage even when the thread or the like should be wedged between the outer and inner shuttles and consequently the inner shuttle should be forced to rotate together with the outer shuttle.

The eighth 'object of the invention is to simplify the manufacturing process as well as to reduce the weight by economizing the use of the materials.

The foregoing several objects can be attained by the combination and function of the improved parts constituting this invention, and the embodiments thereof will be clarified by the accompanying drawing as well as the detailed description hereinafter set forth.

Modifications or alterations of shapes with regard to the details of the structures of the preferred embodiments hereinunder set forth are to be included in the claims which will hereinafter appear.

The invention consists of a reverse lever which, fitted into a depression formed in one part of the inner shuttle, provides a space for the free passage of the thread at the part of the drag by causing the inner shuttle to reverse as the upper thread is passing upward from the inner shuttle, and a cam which is fixed to the shuttle shaft to make the foregoing reverse lever function, the said space being provided at the part of the drag of the inner shuttle by'causing the inner shutttle to slightly reverse in a direction opposite to the rotation of the outer shuttle, taking advantage of the reverse lever activated by the said cam.

FIG. 1 is an elevation of the device for free thread passage of the invention, illustrating the state wherein the reverse lever, fitted into the depression of the inner shuttle, has caused the inner shuttle to reverse slightly.

FIG. .2 is an elevation illustrating the state wherein the reverse lever has departed from the depression of the inner shuttle after the passage of the thread.

FIG. 3 is a lateral view illustrating the relations between the outer and inner shuttles and the drag in the free thread passage device of the invention.

FIG. 4 is a top view illustrating the combination of the outer and inner shuttles and the bobbin thread case of the invention.

FIG. 5 is a sectional bottom view of the foregoing.

FIG. 6 is a bottom view of a sewing machine bed equipped with the free thread passage device of the invention.

FIG. 7 is a diagram showing the function of the device for the free passage of the thread according to the invention.

The free thread passage device of the invention comprises an inner shuttle 12 rotatably fitted inside an outer shuttle 11 a cover 13 provide at the front part of the said inner shuttle 12, a reverse lever 15 to be fitted into a depression 14 of the said cover 13, a cam 16 with which to make the said reverse lever 15 function, and a drag with which to arrest the rotation of the inner shuttle 12 as well as the bobbin thread case 17. The foregoing depression 14 is illustrated in the drawing in the shape of a hole, which however can be replaced by a simple hollow.

The outer shuttle 11 has a removable arcuate lid 19 in the front part thereof. When the said lid 19 is fitted to the front part of the outer shuttle 11 a groove 20 is formed between the lid 19 and the outer shuttle 11. The said groove 20 is to receive the flange 35 on the external rim of the inner shuttle 12, the inner shuttle 12 being easily detachable from the outer shuttle 11 by removing the lid 19. The lid 19 is fastened to the outer shuttle 11 by a couple of metal clasps 21 which are fixed to the outer shuttle 11. Each of the metal clasps 21, being formed by bending a thin plate of spring steel, is rotatably pivoted with a nut 22 on the rear face of the outer shuttle.

The front end 23 of the foregoing metal clasp 21 is so curved as to cover the front side of the lid 19 which is fitted to the front side of the outer shuttle 11, a protrusion 24 formed on the internal side of the said front end 23 being fitted into a hole 25, which is provided in a couple on the lid 19, thereby pressing the lid 19 from the outside to the outer shuttle 11.

Therefore, the protrusion 24 and the hole 25 can be en gaged or disengaged, taking advantage of the flexibility of the metal clasps 21, and hence the lid 19 can be easily disconnected from the outer shuttle 11 by means of removing the metal clasps 21 from the lid 19 by revolving them in the outward direction.

The outer shuttle is fastened to the end of the shuttle shaft 28 fixed to the gear box 27 which is mounted on the lower surface of the sewing machine bed 26 as illustrated in FIG. 6. The numeral 29 indicates the shuttle shaft driving lever shaft fitted to the lower surface of the bed 26, the said lower shaft 29 and the shuttle shaft 28 being coordinated by a gear inside the gear box 27.

It is a matter of course that the outer shuttle 11 is provided with a beak 30 with which to hook the upper thread. On the outside of said beak 30 is formed a space within which to receive the upper thread hooked by the beak as well as an arcuate plate 32 which is placed on the outside of the beak and fastened with screws to the outside of the outer shuttle 11.

The outer shuttle 11 is made of press molded steel plate, the boss 33 being integrally fastened to the rear surface of the outer shuttle 11 by means of Welding. The lid 19 is also made of press molded steel plate or strong synthetic resin, such as ABS resin and the like, with the result that the foregoing members can be produced economically and in light weight with simpler processes and less materials than in the case of forming by means of the conventional lathe.

The inner shuttle 12 consists of an inner shuttle body 34 of press molded steel plate and a tubular cover 13 made by press molding a stoft steel plate for deep extraction, the rear part of the said cover 13 being fitted into the body 34, both the said members 13, 34 being spot welded, an arbor 41 on which to journal the bobbin being welded into the bottom of the body 34. It goes without saying that, though the foregoing members are assembled by means of press molding and welding, the sliding parts thereof are subjected to the lathing and polishing finish. On the upper side of the cover 13 is provided an arm 36 with which to drag the bobbin thread case as well as a notch 38 through which to pass the thread drawn out of the bobbin 37 inside the bobbin thread case 17. On the right side of the said notch 38 is erected upward a protrusion 39 for dragging, a window 40 being provided on the rear part of the notch 38 so that the point of the descending needle may not be damaged.

The reverse lever 15 is fixed to the shaft 42, but it is so arranged that the said reverse lever 15 can be fixed to the shaft 42 at any arbitrary angle by means of revolvably fitting the boss 43 of the lever 15 to the shaft 42 and tightening the shaft 42 with a lock screw 44 which is screwed into the boss 43.

The shaft 42 is revolvably borne by the bearing 45 provided at the front part of the position fixing plate 47 which is fastened to the lower surface of the gear box 27. To the rear end of the shaft 42 is fixed a cam lever 46.

The foregoing cam 16 is fixed to the shuttle shaft 28, but the position of the cam 16 on the shuttle shaft 28 is adjustable as is the position of the shaft 42 and' the reverse lever 15, it being so arranged that the angle between the outer shuttle 11 and the cam 16 can be adjusted. However, the cam 16 can be securely fastened to the shuttle shaft 28, since the position between the 4 shuttle shaft 28 and the outer shuttle is normally adjustable, as in the foregoing case.

The foregoing cam lever 46 is brought in contact with the said cam 16. As to the said cam lever 46, it is so arranged that the annularly curved fitting part 48 thereof, revolvably fitted to the shaft 42, is fastened to the shaft 42 by means of a locking screw 49 screwed into the said fitting part 48, and hence the fitting angle of the cam lever 46 to the shaft 42 can be freely adjusted.

A pull spring 51 is extended between the cam lever 46 and the spring receiver 50 mounted on the position fixing plate 47, the cam lever 46 being constantly pressed to the cam 16 by the force of the said spring 51. The position fixing plate 47, provided with an oblong hole 52 thereon, is fixed by screwing a locking screw 53 through the said oblong hole into the gear box 27. Accordingly, the position of the fixing plate is also adjustable.

The drag 18, made of a spring steel plate and bifurcated, is fastened to the fixing frame 54 by mean of welding or the like method. The said fixing frame which is curved as illustrated in FIG. 6 is fastened to the bed 26 by screwing locking screws 56 through the holes 55 of the fixing frame 54 into the lower surface of the bed 26. The diameter of each hole 55 being slightly larger than the outer diameter of the threaded part of the locking screw 56, the position of the fixing plate 54 against -the bed 26 is adjustable, thereby permitting to adjustment of the position of the drag 18.

The drag 18 is curvilinearly bent as illustrated in FIG. 3, the breadth between the internal sides of the right and left drags 18 being so arranged as to be slightly wider than the aggregated thickness of the protrusion 39 of the inner shuttle 12 and the arm 36 of the bobbin thread case 17.

In FIG. 1, the numeral 57 indicates the needle plate with which to close the window of the sewing machine bed 26, 58 indicating the needle hole, 59 indicating the feeding teeth.

Now, the function of the device according to the invention is this: The same bobbin thread case 17 as that of the ordinary home sewing machine equipped with a semicircularly moving rotatory shuttle is fitted into the inner shuttle 12, the thread 60 drawn from the bobbin 37 fitted into the said inner shuttle 12 being drawn up ward through the inside of the notch 38 provided on the cover 13 of the inner shuttle 12 and then through the needle hole 58 of the needle plate 57.

Though not shown in the figure, the upper thread which is appropriately arranged on the upper part of the sewing machine is inserted into the needle hole at the lower end of the sewing machine needle.

When the sewing machine is driven with cloth placed on the needle plate in the foregoing state, the outer ishuttle 11 rotates in the direction indicated by the arrow, the sewing machine needle lowering, the beak 30 of the outer shuttle 11 hooking up the upper thread passed through the needle. The upper thread hooked up by the beak, forming a loop, travels round the outside of the inner shuttle until the said thread is drawn upward and forms a stitch together with the lower thread.

When the outer shutter 11 rotates as described above, the inner shuttle 12 is urged to rotate together with the said outer shuttle but remains stationary as the protrusion 39 of the inner shuttle 12 is arrested by the drag 18, the bobbin thread case 17 also remaining stationary, the arm 36 thereof being arrested by the protrusion 39.

Furthermore, according as the outer shuttle 11 rotates as described above, the cam 16 also rotates together with the outer shuttle 11, the cam lever 46 which is constantly in contact with the said cam 16 oscillating according to the rotation of the said cam 16.

As the cam lever 46 oscillates, the shaft 42 and the reverse lever 15 oscillate in coordination, with the result that the terminal part of the lever 15 goes in and out of the depression 14 provided on the cover .13 thereby causing the inner shuttle to slightly reverse once per rotation, the timing of which is as set forth hereinunder.

' While the upper thread is traveling round the outside of the inner shuttle 12, being hooked up by the beak and forming a loop, the cam lever 46 is in contact with the lower part of the cam 16 as illustrated in FIG. 2, as a result of which the reverse lever 15 is lowered and detached from the lower side of the inner shuttle 12. Consequently, the loop of the upper thread which travels round the outside of the inner shuttle 12 freely passes between the lower side of the cover 13 and the reverse lever 15 without interference from the reverse lever 15.

At the time when the loop of the upper thread, which passed the lower side of the inner shuttle 12, passes upward along the right side of the inner shuttle 12, having slipped off the beak 30, the terminal part of the reverse lever 15 fits in with the depression .14 of the cover 13 as illustrated in FIG. 1, thereby causing the inner shuttle 12 including the cover 13 to make a slight reversion, with the result that some space is formed between the protrusion 39 and the drag 18, the upper thread passing through the said space without receiving any resistance.

The reversing function of the inner shuttler 12 by means of the reverse lever 15 will be described in reference to FIG. 7. When the reverse lever 15 is located in the position designated by the solid line in FIG. 7, the end 61 of the lever 15 is disengaged from the depression 14 formed on the tubular cover 13 of the inner shuttle 12, the depression 14 of the cover 13 being located in the position indicated by the solid line in FIG. 7. At this juncture, the protrusion 39 is in contact with the drag 18 in consequence of the rotation of the outer shuttle 11 as show in FIG. 2.

When the cam 16 proceeds to the position indicated by the broken line in FIG. 7, the cam lever 46 and the reverse lever 15 being brought to the respective positions indicated by the broken lines in FIG. 7, the front end 61 of the reverse lever 15 fits into the depression 14 of the cover 13.

Since the moving direction of the front end 61 is along a circular arc centering on the shaft 42, the rear edge 62 of said end 61 which fits into the depression 14 causes the rear edge 63 of the depression 14 to reverse by the given angle as indicated by the broken line in FIG. 7. As a result, space necessary for the free passage of the thread is formed between the protrusion 39 and the drag 18 as illustrated in FIG. 1.

When the loop of the upper thread passes between the protrusion 39 and the drag 18 as described above, the loop of the upper thread is by no means caught in the drag 18, the said drag 18 being curved in the shape of a smooth are as illustrated in FIG. 3.

The thread traveling smoothly with no resistance at the time of the thread passage, not only well tightened stitches are obtainable but also the noise at the time of the thread pasage can be prevented completely.

The cam lever 46 being constantly brought in contact with the cam 16 by the flexibility of the spring 51, the usual noise owing to a collision of the cam 16 against the cam lever 46 can be perfectly prevented.

The timing of the reversion of the inner shuttle 12 caused by the fitting of the end of the reverse lever into the depression 14 can be freely adjustedby adjusting the angle between the reverse lever 15 and the cam lever 46 on the shaft 42 as Well as by adjusting the position of the cam 16 on the shuttle shaft 28.

As the lower thread travels to the needle hole 58 through the inside of the notch provided on the upper side of the cover 13, the said lower thread is never brought backward any farther than the position of the notch 38. As the lower thread is thus sustained steadily by the notch 38 considerably ahead of the revolving range of the beak 30 of the outer shuttle 11, there is no risk of the lower thread being hooked and broken by the beak or being wedged between the outer shuttle 11 and the inner shuttle 12. As a result, the outer shuttle 11 no longer requires the conventional thread arranging board with which to arrange the lower thread so as not to be hooked by the beak.

As compared with the outer shuttle of the conventional full rotatory sewing machine, the outer shuttle 11 of the invention is lighter in weight and has less inertia during the rotation. Moreover, the distance between the center of the outer shuttler 11 and the contact point of the protrusion 39 and the drag 18 is greater than that of the conventional machine, as a result of which the contact pressure is reduced.

Accordingly, even when the reverse lever should fail to function satisfactorily, resulting in insufiicient space between the drag 18 and the protrusion 49, the passage of the upper thread through the said space is effected without any appreciable resistance, because not only the contact between the drag 1-8 and the protrusion 39 is not very strong but the drag 18 performs a bulfer function as well It scarcely happens that the thread is wedged between the outer shuttle 11 and the inner shuttle 12, but even if such should happen, the lid 19 would push the front ends 23 of the metal clasps 21 thereby producing a space between the groove 20 of the outer shuttle and the flange 35 of the inner shuttle and easing the resistance arising between the outer shuttle 11 and inner shuttle 12, with the result that possible damage of the protrusion 39 and the drag 18 is prevented by the prevention of stoppage of the rotation of the outer shuttle 11.

As the lid 19 is easily detachable by operating the metal clasps 21, the inner shuttle 12 can be disconnected from the outer shuttle 11 with ease whenever it is necessary to remove the thread or the like wedged between the outer shuttle 11 and the inner shuttle 12.

As per the foregoing description, in the free thread passage device of the invention the passage of the thread is effected with extreme smoothness, beautiful regular stitches being obtainable with a smooth sewing performance, the noise being minimized, disassembling being feasible with ease for the removal of wedged thread or the like, efficient manufacture being practicable because of the fact that each part is produceable chiefly by press molding.

Moreover, the device of the invention has further distinguished characteristics, for instance, the bobbin and the bobbin thread case of the commonly used home sewing machine equipped with a semi-rotatory shuttle are utilizable without any adapter.

What is claimed is:

1. A device for providing free thread passage in a sewing machine comprising an outer shuttle of the full rotary type mounted on said sewing machine, an inner shuttle fitted into said outer shuttle, a bobbin thread case re ceived in said inner shuttle, a protrusion erected at one part of said inner shuttle, an arm provided on said bobbin thread case, drag means mounted on said sewing machine for arresting rotation of said inner shuttle and said bobbin thread case by catching said protrusion and said arm when said outer shuttle rotates, reverse lever means mounted on said sewing machine for causing the said inner shuttle to make a temporary rotation in a direction opposite to the direction of rotation of said outer shuttle, and cam means for activating said reverse lever means at an appropriaite moment.

2. A device for providing free thread passage as set forth in claim 1, further comprising a rotatable shuttle shaft mounted on said sewing machine for said outer shuttle mounted on said shuttle shaft, said cam means comprising a cam mounted on said shuttle shaft, a cam lever contacting said cam and adjustably fixed to a shaft which is revolvably borne by a bearing mounted on said sewing machine adjacent said shuttle shaft, spring means for constantly urging said cam lever to contact said cam,

7 and said reverse'lever means being adjustably mounted on said shaft.

3. A device for providing free thread passage as set forth in claim 1, further comprising a beak mounted on said outer shuttle, a cover enclosing the outside of said bobbin thread case and positioned at the front part of said inner shuttle, said cover having at the lower side thereof a depression into which the end of said reverse lever means fits to cause said inner shuttle to make said temporary rotation, said cover having in the front part of the upper side thereof a notch which, by receiving thread drawn from said bobbin thread case, maintains said thread outside the path of said rotating beak, said arm extending through said notch, and said protrusion being formed adjacent said notch.

4. A device for providing free thread passage as set forth in claim 1, wherein said drag means comprises an arcuately curved thin flexible plate, said drag being mounted on a frame, said frame being adjustably fastened to the lower surface of the bed of said sewing machine.

5. A device for providing free -thread passage as set forth in claim 1, further comprising a flange on the outer periphery of said inner shuttle, arcuate lid means for preventing said inner shuttle from being detached from said outer shuttle by pressing said flange into said outer.shut-. tle, metal clasp means fixed to said outer shuttle for pressing said lid means onto said outer shuttle, said lid means and said outer shuttle being freely combinable and separable by revolving said metal clasp means. 1

References Cited UNITED STATES PATENTS 1,146,001 7/1915 La Chapelle 1l2232 1,173,973 2/1916 Illig 1l2232 X 2,248,347 7/1941 Haas 1l2--232 X 1,991,456 2/1935 Gouldbourn et a1. 1l22 32X ALFRED R. GUEST, Primary Examiner

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