US3050021A - Lower thread adjusting apparatus in sewing machines - Google Patents

Description

1962 TOMIO FUKUSHIMA 3,050,021

LOWER THREAD ADJUSTING APPARATUS IN SEWING MACHINES Filed Feb. 1, 1960 5 Sheets-Sheet 1 mNaVvra Tam/0 FUK H 1, 1962 TOMIO FUKUSHIMA 3,050,021

LOWER THREAD ADJUSTING APPARATUS IN SEWING MACHINES Filed Feb. 1, 1960 5 Sheets-Sheet 2 Aug. 21, 1962 TOMIO FUKUSHIMA LOWER THREAD ADJUSTING APPARATUS IN SEWING MACHINES 5 Sheets-Sheet 3 Filed Feb. 1, 1960 Aug. 21, 1962 TOMlO FUKUSHIMA 3,050,021

LOWER THREAD ADJUSTING APPARATUS IN SEWING MACHINES Filed Feb. 1, 1960 5 Sheets-Sheet 4 /Q l m 1 t J Z2 47 Z 2 30 27 //Y rs/v n K 70 mm Fum/ H/MA Aug. 21, 1962 TOMlO FUKUSHIMA LOWER THREAD ADJUSTING APPARATUS IN SEW ING MACHINES 5 Sheets-Sheet 5 Filed Feb. 1, 1960 IIIIIIIIII United States Patent 3,050,021 LOWER THREAD ADJUSTING APPARATUS IN SEWING MACI MES Tomio Fukushima, Osaka City, Japan, assignor to Kabushiki Kaisha Tohoku Kosakusho, akai City, Japan Filed Feb. 1, 1960, Ser. No. 5,932 6 Ciaims. (Cl. 112-229) This invention relates to a lower thread adjusting apparatus in a sewing machine.

In a known sewing machine, it takes much trouble to adjust the tension of the lower thread; taking out the bobbin case from the shuttle or if it cannot be taken out, putting a screw driver into the back of the machine, to turn the adjusting screw.

The object of the present invention is to provide means to turn the adjusting screw without these troubles.

With this object in view the present invention provides a lower thread adjusting apparatus in a sewing machine wherein by working a knob installed at some proper place of the machine, the adjusting screw can be turned through a remote operation mechanism with the bobbin case laid as it is in the shuttle.

Other and the further objects of the present invention will become apparent from the following specification and claims taken together with the accompanying drawings in which is shown the preferred embodiment of the lower thread adjusting apparatus in a sewing machine according to the present invention.

FIG. 1 is a plan view of a lower thread adjusting apparatus for a horizontal rotation shuttle type sewing machine according to the present invention.

FIG. 2 is an elevation view of FIG. 1.

FIG. 3 is a sectional side view of FIG. 2.

FIG. 4 is an underside view partly in section of a lower thread adjusting apparatus for a vertical semi-circular rotation shuttle type sewing machine according to the present invention.

FIG. 5 is a sectional side view of FIG. 4.

FIG. 6 is an elevation view of FIG. 4.

FIG. 7 is an elevation View of a shuttle driver shown in FIG. 6.

FIG. 8 is an elevation view of a cam.

FIG. 9 is a sectional elevation of a lower thread adjusting apparatus for a vertical full revolution type sewing machine according to the present invention.

FIG. 10 is an elevation View of a bobbin case shown in FIG. 9.

FIG. 11 is a side view of FIG. 10.

FIG. 12 is a sectional side view of FIG. 10.

FIG. 13 is an enlarged sectional view of a part of FIG. 10.

FIG. 14 is a perspective view of a bobbin case.

In FIGS. 1, 2 and 3 reference numeral 21 indicates a bobbin case set in a shuttle. A thread wound on a bobbin in the bobbin case 21 is pressed by a thread press spring 22, of which the pressing force is adjusted by an adjusting screw 23. In a frame 24 fixed on the underside of a bed 25 is rotatably and slidably mounted a driving rod 26 provided with a pinion 27 on one end and screw engaging blades on the other end and kept apart from the adjusting screw 23 by a spring 28. On supporters 29, 29 fixed on the underside of the bed 25 is mounted a rack 30 meshed with the pinion 27. A shaft 31 of a knob 32 is passed through a rotatable cylinder 33 fitted in a frame 34 fixed on the underside of the bed 25, provided with a spring 35. A pin 36 screwed through the side-wall of the knob 32 fits in a vertical guide way 37 cut on the side wall of the cylinder 33. A pinion 38 furnished on the lower part of the cylinder 33 is meshed with the rack 30. At the rear end of a lever 39 supported on a pin 40 fixed to the bed 25 is formed a cam 3,955,921 Patented Aug. 21, 1962 41 to co-operate with the shaft 31, and the fore end of it is kept in contact with the driving rod 26. The frame 24 is provided with a stopper 24 to hold the pinion 27 while the driving rod 26 is kept apart from the adjusting screw 23.

When the knob 32 is pushed down, the cam 41 formed on the rear end of the lever 39 is pushed aside by the lower end of the shaft 31, as shown in a chain line in FIG. 1, the fore end of the lever 39 pushing the driving rod 26, of which the bladed end catches in the head of the adjusting screw 23. Then by turning the knob 32, the rotatable cylinder is rotated, the pin 36 catching in the guide way '37, and the rack 30 meshed with the pinion 38 goes back and forth to turn the pinion 27 and the driving rod 26, whereby the adjusting screw 23 turns to adjust the pressing force of the thread press spring 22.

In FIGS. 4, 5, 6, 7 and 8 is shown a lower thread adjusting apparatus for a sewing machine of a vertical semicircular rotation shuttle type according to the present invention. A bobbin case 21 is removably fitted in a shuttle 42 set in a case 43. The driving rod 26 for the adjusting screw 23 is slidably and rotatably fitted in a hole 44 bored on the case 43, supported by the frame 24. A pass Way 4-5 for the driving rod 26 is cut on a shuttle driver 46. The shaft 31 of the knob 32 is passed through an inclined opening 47 bored on the upper side of the bed 25 and supported by the frame 34. The pinions 27 and 38 are meshed with the crown gears 30, 30- mounted on both ends of a connecting rod 48. On a shaft 49 is mounted a cam 50 on which is cut a recess 51 at the position corresponding to the pass way 45 on the shuttle driver 46 so as to co-operate with a projection 52 formed On the lever 39.

When the projection 52 gets in the recess 51, with the pass way 45 ready to admit the driving rod 26, the knob 32 can be pushed for the bladed end of the driving rod 26 to catch in the head of the adjusting screw 23, and

-by turning the knob 32 the adjusting screw 23 turns to adjust the pressing force of the thread press spring 22.

In FIGS. 9, 10, 11, 12, 13, and 14 is shown a lower thread adjusting apparatus for a sewing machine of a vertical full rotation shuttle type according to the present invention. The driving rod 26 is slidably and rotatably set in the hollow shaft 49, supported by the frame 24 and provided with the pinion 27 to be turned by the crown gear 30 mounted on the shaft 31 of the knob 32 (not shown). The end of the lever 29 to work on pushing the knob 32 is kept in contact with the rear end of the driving rod 26. In an intermediate case 53 set in the shuttle 4-2 is fitted the cylindrical bobbin case 21 provided with a partition wall 54. An inclined thread way 55 is cut on the rear circumferential wall 56 of the bobbin case 21, and on its front circumferential wall 56 having a notch 57 are cut thread ways 58 and 59. At the center of the bobbin case 21 is formed a cylinder 60, in which is loosely inserted the adjusting screw 23, of which the head faces the end of the driving rod 26 and the tail is screwed in a screw hole 61 of the thread press spring 22 placed on the front wall 54. The upper part of the partition wall 54 is furnished with a rotatable piece 62 having a projection 63 and its bent part 64 is kept projecting through an opening 65 of the front circumferential wall 56 by a spring 66 and catches in an opening 67 of the intermediate case 53. Between the cylinder 60 and the thread adjusting screw 23 is laid a spring 68 for counteracting the pressure of the thread press spring 22.

In a lower thread adjusting apparatus constructed as above, the pressure of the thread press spring 22 upon the partition wall 54 can be adjusted by thrusting out the driving rod 26 and turning the adjusting screw 23, and the lower thread from the bobbin, led through the thread way 55 and then to be taken out through the thread way 59, is adjusted in tension when passing between the partition Wall 54 and the thread press spring 22.

According to the present invention, a lower thread in a bobbin case installed under a machine bed can be adjusted in tension at will by working a knob furnished at some proper place on the machine, and thus the tension of the lower thread can easily be kept best to produce excellent goods with much efiiciency.

It is thought that the invention and its advantages will be understood from the foregoing description and it is apparent that various changes may be made in the form, constructions and arrangement of the parts without departing from the spirit and scope of the invention or sacrificing its material advantages, the form hereinbefore described in the drawings being merely a preferred embodiment thereof.

Having thus described my invention, what I claim and desire to secure by Letters Patent of the United States is:

l. A device for adjusting thread tension on a sewing machine bobbin in which the bobbin has thread tensioning means thereon, said device comprising an adjusting shaft adapted to be mounted on the sewing machine adjacent the thread tensioning means for rotatable and slidable movement longitudinally of its length and having engaging means on one end thereof for engaging the thread tensioning means on the bobbin, a first spring means engaging said adjusting shaft and urging said adjusting shaft away from the bobbin, a first pinion on said adjusting shaft, an actuating shaft adapted to be mounted on the sewing machine adjacent said adjusting shaft for rotatable and slidable movement along its length and having a second pinion thereon, said pinions being drivingly connected to each other, a second spring means urging said actuating shaft longitudinally of its length toward one end thereof, and a lever pivotally mounted between said shafts and having one end engaging the other end of said adjusting shaft and having the other end engaging the other end of said actuating shaft.

2. A device as claimed in claim 1 in which a rack is provided and forms the driving connection between said pinions, said pinions being engaged with said rack and being slidable transversely of the length of said rack.

3. A device as claimed in claim 1 in which a rotatable shaft is provided having a crown gear on each end thereof engaging with said pinions for drivingly connecting the pinions.

4. A device as claimed in claim 1 in which said shafts are at an angle to each other end spaced from each other, and a rack is provided for drivingly connecting said pinions, said pinions being engaged with said rack for sliding movement transversely of the length of said rack, said rack having two faces, one engaged with the pinion on the adjusting shaft and the other engaged with the pinion on the actuating shaft, and said lever having the end engaged with said actuating shaft at an acute angle to the direction of the length of the actuating shaft.

5. A device as claimed in claim 4 and a stop pin engageable with the pinion on said adjusting shaft when said pinion is in the position remote from said bobbin.

6. A device as claimed in claim 1 in which a rotatable shaft is provided having a crown gear on each end engaging with said pinions for drivingly connecting said pinions, said adjusting shaft and said actuating shaft being at an angle to each other, and said lever having the end engaging the said other end of the actuating shaft bent at an angle to the end of the lever engaging the other end of said adjusting shaft, said last mentioned angle being substantially equal to the angle at which said actuating shaft is in relation to said adjusting shaft, and an aligning pin on said lever and an aligning ca m adapted to be rotatably mounted on the sewing machine in engagement with said aligning pin, said aligning cam being adapted to be rotated in synchronism with said bobbin, said aligning cam having a recess adapted to be aligned with the tensioning means on said bobbin, whereby said aligning pin is received in said recess only when said adjusting shaft is aligned wit-h the thread tensioning means.

References Cited in the file of this patent UNITED STATES PATENTS 1,264,284 Denne Apr. 30, 1918 2,441,881 Potter et al Jan. 9, 1923 2,582,211 Turner Jan. 8, 1952 2,907,292 Schenkengel Oct. 6, 1959

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