US3486473A

US3486473A - Non-spill bobbin case for sewing machines

Info

Publication number: US3486473A
Application number: US694459A
Authority: US
Inventors: Roger J Ross
Original assignee: Singer Co
Current assignee: Singer Co
Priority date: 1967-12-29
Filing date: 1967-12-29
Publication date: 1969-12-30
Anticipated expiration: 1986-12-30
Also published as: FR1595709A; GB1189069A; DE6812868U; DE1816564A1

Description

Dec. 30, 1969 R. J. Ros 3,486,473

NON'SPILL BOBBIN CASE FOR SEWING MACHINES Filed Dec. 29, 1967 4 Sheets-Sheet 1 CONTROL SYSTEM Fig. I.

Fig. l5. v

ZQ-wa 366 INVENTOR.

Roger J. Ross WITNESS I I '.v i I W7 ATTORNEY R. J. ROSS Dec. 30, 1969 N NON-SPILL BOBBIN CASE FOR S EWI NG MACHINES Filed Dec. 29. 1967 4 Sheets-Sheet z m T m V m w/msss .BY w hz i AZTORNETY Dec. 30, 1969 R. J. Ross NON-SPILL BOBBINCASE FOR-'SEWING-MACHINES Filed Dec. 29, 1967 4 Sheets-Sheet 5 S S o R J f e g 0 n ATTORNEY Dec. 30, 1969 R. J. ROSS NON'SPILL BOBBIN CASE FOR SEWING MACHINES Filed Dec. 29, 1967 4 Sheets-Sheet 4 New INVENTOR.

. Roger J. Ross United States Patent 3,486,473 NON-SPILL BOBBIN CASE FOR SEWING MACHINES Roger J. Ross, Herrick Drive, N.J., assignor to The Singer Company, New York, N.Y., a corporation of New Jersey Continuation-impart of application Ser. No. 483,696, Aug. 30, 1965. This application Dec. 29, 1967, Ser.

Int. Cl. Db 57/26 US. Cl. 112-229 4 Claims ABSTRACT OF THE DISCLOSURE This disclosure relates to a non-spill bobbin case for a loop taker of a sewing machine in which a brake device is pivotally mounted in the bobbin case and normally biased into engagement with the bobbin to prevent bobbin rotation. Drawing the bobbin thread in a prescribed manner will act to release the brake device from the bobbin to permit the bobbin thread to be dispensed during the period of positive feed. Thereafter the brake is automatically re-applied to prevent over-spilling of the bobbin thread.

Some of the operations which result in positive feed of the bobbin thread are the'setting of the lock stitch, the motion of a bobbin case support mechanism in aiding stitch formation, and drawing of the bobbin thread by a thread trimming mechanism for the trimming operation.

The brake device is associated with a tensioning means for the bobbin thread.

CROSS REFERENCE TO RELATED APPLICATION This application is a continuation-in-part of my copending application, Ser. No. 483,696, filed Aug. 30, 1965 for Stitch Forming Mechanism for Sewing Machines.

BACKGROUND OF THE INVENTION Heretofore bobbin case frictional brake devices relied on either the indirect application of a drag upon the bobbin or a continuous frictional force applied directly against the bobbin that resulted in both a variable tension of the bobbin thread and an inability to prevent spilling of the bobbin thread whenever it was drawn suddenly.

SUMMARY OF THE INVENTION In accordance with the present invention the non-spill bobbin case provides stitch forming instrumentalities of sewing machines with a brake device which normally prevents feeding of at least one of the threads thereof, most usually the bobbin thread which is more susceptible of spilling, but is releasable responsive to the positive drawing of said thread such as occurs when said thread is drawn to form or set a stitch, or to be positioned for cutting thereof, or the like. The novel non-spill bobbin case may be used in almost any sewing machine, whether of conventional or particular design, or in combination with a trimming mechanism, or whenever the bobbin thread is likely to be subjected to intermittent drawing thereof.

It is therefore an object of the present invention to provide an improved non-spill bobbin case for a loop taker of a sewing machine which overcomes the prior art difliculties; which is usable in combination with a thread trimming mechanism; which is usable in any lock stitch sewing machine, conventional or otherwise; which permits positive drawing of the bobbin thread; which uses a releasable brake device to prevent overspilling of the bobbin thread; which limits the drawing of the bobbin thread during stitch formation to those periods of positive feed thereof; which uses a cooperative tensioning means and 3,486,473 Patented Dec. 30, 1969 "ice BRIEF DESCRIPTION OF THE DRAWINGS This invention is illustrated in the accompanying drawings in which:

FIGURE 1 is a schematic representation of a sewing machine having a trimming device and controls therefor.

FIGURE 2 is a fragmentary perspective view of a loop taker, a needle and take-up associated with a thread trimming mechanism shown in position prior to operation thereof.

FIGURE 3 is a fragmentary perspective view showing the thread trimming mechanism illustrated in FIGURE 2 shown immediately subsequent to operation thereof.

FIGURE 4 is a perspective view of one form of the improved nonspill bobbin case.

FIGURE 5 is a partial sectional view of the closed end of the bobbin case of FIGURE 4 showing the brake device engaging the bobbin flange.

FIGURE 6 is a partial sectional view of the bobbin case of FIGURE 5 showing the brake device released from the bobbin flange.

FIGURE 7 is a perspective view of another form of the improved non-spill bobbin case.

FIGURE 8 is a partial sectional view of the closed end of the bobbin case of FIGURE 7 showing brake device engaging the bobbin flange.

FIGURE 9 is a partial sectional view of the bobbin case of FIGURE 8 showing the brake device released from the bobbin flange.

FIGURE 10 is a top plan view of still another form of the improved non-spill bobbin case embodied in another type of a loop taker.

FIGURE 11 is a side elevational view taken along line 1111 of FIGURE 10.

FIGURE 12 is a top plan view of the bobbin case of FIGURE 10 including the needle and bobbin threads during manipulation of the needle thread loop by the loop taker.

FIGURE 13 is a top plan view of the bobbin case of FIGURE 10 with the needle and bobbin threads in position for setting of a stitch.

FIGURE 14 is a side elevational view taken along line 14-14 of FIGURE 13.

FIGURE 15 is a top plan view of the loop taker of FIGURE 10 and the supporting arm therefor at one eX- tremity of oscillation of said supporting arm and illustrating in broken lines the path of motion of the loop seizing beak and the bobbin thread delivery guide means of the bobbin case.

DESCRIPTION OF THE INVENTION The novel non-spill bobbin case is designed for use in a sewing machine, for example it may be embodied in a conventional sewing machine, such as is shown in FIG- URE 1 and designated generally as 20. In order to understand the present invention, a brief description of sewing machine 20 will be set forth herein, but for a more detailed description of this machine and the operation components thereof reference may be had to the copending United States patent application entitled Thread Trimming Mechanism for Sewing Machines, United States Ser. No. 562,576, filed July 5, 1966.

The sewing machine 20 has a frame 22 that includes a bed 24 having a standard 26 thereon, from which is cantilevered a bracket arm 28 having its opposite end terminate in a head 30 that overhangs the bed 24. The stitch forming instrumentalities, generally designated as 32, are mounted in the frame 22 of the machine 20 as will be more fully explained hereinafter. A trimming mechanism 34 is disposed in the bed 24 adjacent a loop taker 36 of the stitch forming instrumentalities 32. The frame 22 is suitably supported in the top of a leg supported table 37.

A suitable control system 38 is adapted to operate the trimming mechanism 34 and includes the schematically represented units shown in FIGURE 1. A needle positioning device including a clutch-and-timer unit 40 is secured in place of the conventional balance wheel and will act to time the operation of the trimming mechanism 34. A detailed description of unit 40 may be had by reference to United States Patent No. 2,942,564. The clutch of the unit 40 is double acting and is biased to connect a transmitter belt 42 driven by a conventional clutch-brake transmitter 44 to the arm shaft (not shown) of the sewing machine 20. On signal from the control system 38 the clutch-and-timer unit 40 drives the clutch therein into a position connecting an auxiliary belt 46 to the arm shaft. The auxiliary motor 48 is operable at a lower speed which permits slow and accurate needle positioning. A normallyclosed control switch 50 is secured to the operating lever 52 of the transmitter 44. The lever 52 operates to control the clutch and brake thereof. The control switch 50 will be opened to remove the power from the units of the control system 38 when the operating lever 52 is lowered by depressing a treadle 54. Lowering of the lever 52 releases the brake and engages the clutch of the transmitter 44 to drive the belt 42.

When the operator raises the lower length of the pitman 56 connecting the treadle 54 to the lever 52 a normally-open switch 58 will be closed to cause the control system 38 to position a needle 60 of the stitch forming instrumentalities 32 to extend downwardly into the bed 24. Then the transmitter 44 will be in a braked condition and the system will be prepared for trimming. A switch 62 at the treadle is provided to permit sewing of additional stitches, and thereafter, the operator actuates the switch 58 to place the needle 60 in the down position and prepare the system for the trimming operation.

The stitch forming instrumentalities 32, illustrated in FIGURES 2 and 3, includes the vertically reciprocated needle 60 and associated thread take-up member 62 which manipulates the needle thread in the conventional manner, and cooperates with the loop taker 36 to concatenate the needle and

bobbin threads

64 and 66, respectively, into a series of lock stitches, shown schematically and designated generally as 68. The loop taker 36 includes a rotary hook which is secured to a bed shaft 72 journaled in the bed 24 to rotate the hook 70 two revolutions for each vertical reciprocation of the needle 60 as is conventional for this type of sewing machine 20. Journaled within the rotary hook 70 is a bobbin case 74 which is prevented from rotating by a rotation restraining finger 76 secured to the bed 24 of the sewing machine 20 and inserted into a rotation restraining notch 78 in the bobbin case 74. The rotary hook 70 includes a hook beak 71 which partakes of two revoltuions in cooperation with each vertical reciprocation of the needle 16 to seize loops of thread from the needle and to concatenate the seized thread loops about the bobbin case to form lock stitches. A bobbin 80 carries a supply of the bobbin thread 66 therein and is disposed in the bobbin case 74 so that the axis of rotation of the bobbin 80 is coincident with the axis of rotation of the bed shaft 72.

Subsequent to actuation of the switch 58 to place the needle 60 in the down position, the operator shifts a knee pedal 81 to close a switch 83, shown in FIGURE 1 which sets the trimming mechanism 34 into operation. The trimming mechanism 34 includes a thread engaging element or finger 82 and a blade 84 suitably connected to be actuated by the control system 38. The closing of the switch 83 causes the thread engaging finger 82 to be driven into the position represented in FIGURE 2, simultaneously raising the needle 60 to the up position and on raising of the needle the finger 82 draws the needle and

bobbin thread

64 and 66, respectively, prior to the control system 38 effecting operation of the blade 84 to cut the same, as is illustrated in FIGURE 3.

The thread engaging finger 82 has a thread catching hook 86 on the end thereof adjacent the bobbin case 74, which hook is insertable into a thread catching aperture 88 formed in the otherwise conventional bobbin case 74. The thread catching hook 86, as shown in FIGURE 2, will be positioned in the thread catching aperture 88 so that the bobbin thread 66 and the loop formed on the needle thread 64 will be pulled against it by the counter-clockwise rotation of the hook beak 71 whereby on retraction of the thread catching finger 82, the thread catching hook 86 will draw the bobbin thread 66 andthe loop formed of the needle thread 64 away from the rotary hook 70 and to the left, as .viewed in FIGURE 3. However, the work limb N of the needle thread 64 and the bobbin thread 66 passing to the work represented by the line of stitches 68 are drawn behind the rotation restraining finger 76, whereas the needle limb N of the needle thread 64 is drawn by the hook beak 71 into a position finally overlaying the rotation restraining finger 76, as shown in FIGURE 3.

The thread catching hook 86 is preferably inserted into the thread catching aperture 88 when the needle 60 is in its lower dead center position, approximately at the time when the hook beak 71 is first engaging a loop of the needle thread 64. As the hook beak 71 rotates the needle loop is pulled thereby against the thread catching finger 82, and the bobbin thread 66 is positioned in a slot 92 in the bobbin case 74 which slot 92 is aligned with the thread catching aperture 88 and the path traversed by the thread catching finger 82 and the hook 86 during a stroke thereof.

After the thread limbs have been caught and drawn outwardly by the thread catching hook 86 to a sufficient length to permit cutting of the needle and

bobbin threads

64 and 66 respectively, for resumption of sewing following trimming without manipulation, the blade 84 can be drawn across the work limb N of the needle thread 64 and the bobbin thread 66. Because the blade 84 travels below the needle limb N that limb will not be trimmed and will remain long enough for commencement of the next sewing operation. When the cutting stroke occurs, preferably at top dead center of the needle 60, the needle take-up member 62 will be raised, in the conventional manner, for tightening the last stitch 68 and providing tension on the threads. Provisions of adequate tension permits the use of a single blade 84 operative without an opposing blade, i.e., without a scissors action, to trim the limbs of thread the same as if they were struck by a blade with considerable impact. Tension also assures that the needle limb N will not be cut because it is retained by the thread catching hook 86, the rotation restraining finger 76 and the wall of a needle aperture 94 in a throat plate, (not shown) sufficiently distant from the blade 84.

The trimming mechanism 34 described herein is basically the same as that shown and described in the United States patent application for a Thread Trimming Mechanism for Sewing Machines, United States Ser. No. 562,576, filed July 5, 1966, to which reference may be had for a more complete understanding thereof.

In any event, the present invention is contemplated for use with any one of a variety of trimming mechanisms or for that matter may be associated with any sewing machine or device thereof the operation of which results in the bobbin thread being drawn intermittently, suddenly or other than at a constant rate so as to produce a tendency for spilling of the bobbin thread that would interfere with the normal feeding thereof. It is the principal object of the present invention to prevent the spilling of the bobbin thread by providing a non-spill bobbin case as is illustrated in the several embodiments of the present invention set forth hereinafter.

In the embodiment of the invention illustrated in FIG- URES 4, 5 and 6 an improved non-spill bobbin case 100 is shown adapted for use in a suitable loop taker (not shown) of a lock stitch sewing machine, for example the. loop taker 36 of sewing machine which machine may include a trimming mechanism 102 generally represented in FIGURE 4 by the hook ended thread engaging finger.

The bobbin case 100 has an end wall 104 in which is diametrically disposed a pivotable grip 106 on one side of which is formed a rotation restraining notch 108. An annular flange 110 extends from the outer periphery of the endwall 104 perpendicularly therefrom so that the case 100 is substantially basket shaped.

The end of the case 100' opposite the wall 104 is open to receive a bobbin 112. The bobbin has an annular hub 114 having an inner circular flange 116 and an outer circular flange 118 connected at either end thereof. A supply of bobbin thread 120 is wound about the hub 114 between the

flanges

116 and 118. The bobbin 112 is free to rotate relative a bobbin case 100, with the axis of rotation substantially parallel to the flange 110.

On the side of the case 100 opposite the notch 108 an elongated slot 122 is formed for a brake device that is designated generally as 124. The brake device 124 includes a lever 126 having a brake finger 128 extending from one end thereof and a slotted thread engaging portion or finger 130 formed at the other end thereof. The lever 126 is pivotally connected into the slot 122 by a pin 132 so as to extend substantially parallel to the end wall 104, with

fingers

128 and 130 substantially perpendicular thereto. The

fingers

128 and 130 and the pin 132 are disposed parallel to the axis of rotation of the bobbin 112.

A tensioning means in the form of a biasing spring 134 is connected to the flange 110 by a screw 136 which is turnable to adjust the biasing force exerted thereby. An end 138 of the spring 134 engages the brake finger 128 to bias it into engagement with the flange 118 of the bobbin 112. The other end 140 of the spring 134 extends along the flange 110 passing under the thread engaging finger 130 to define a thread guiding means.

The flange 110' of the bobbin case 100 has thread guiding means formed on either side of the spring thread guiding means 140. More particularly, a slot 142 is formed adjacent the finger 130, while a thread guide 144 is formed beyond the guiding means 140 on the outer periphery of said flange. The bobbin thread will be passed out of the case 100 through the slot 142 of the flange 110 to be disposed through the slotted thread engaging finger 130 prior to passing under the guiding means 140 which presses the thread against the flange 100, before the thread finally exits out of the hole in the thread guide 144 from which point it may be drawn intermittently by the stitch forming instrumentalities (not shown) or other mechanism, or the like.

The brake finger 128 of the brake device 124 is normally biased into engagement with the flange 118 of the bobbin 112 and thereby acts to prevent issuance of the bobbin thread 120. However, the brake finger 128 will be released whenever the bobbin thread 120 is drawn to create an opposing force at the thread engaging finger 130 which overcomes the biasing force of the spring 134 and results in the lever 126 pivoting as illustrated in FIGURE 6, to release the brake finger 128 from engagement with the flange 118. So long as the bobbin thread 120 is being positively fed the thread engaging finger 130 will continue to be urged in the direction of the flange 110 thereby permitting the bobbin 112 to rotate 6 and the bobbin thread to be fed. On the cessation of bobbin thread feeding the tension spring 134 will immediately bias the brake finger 128 into re-engagement with the flange 118 to brake the bobbin turning and prevent over-spilling of the bobbin thread 120.

The distance from the pivot pin 132 to the thread engaging finger is substantially three times longer than the distance from the pivot pin 132 to the brake finger 128 whereby the force exerted at the finger 130 need be only a fraction of that exerted on the brake finger 128 to overcome the same. In other words the moment arm from the pin 132 to the finger 130 being three times greater will require a force of slightly more than onethird that of the spring 134 force.

Accordingly, the release of the brake finger 128 is effected almost immediately on the bobbin thread 120 being drawn. In this manner, there is no interference with the normal sewing operation or other acts which result in a drawing of the bobbin thread 120. Additional benefits derived from the use of the brake device 124 are that of having the bobbin thread 120 remain under constant tension in that there is no change in the effective moment arm, regardless of whether the bobbin thread supply is full or empty because said moment arm will not be measured from within the case 100, but will take effect from the point the thread crosses over the finger 130 in a manner that was not possible in the bobbin cases of the prior art.

In the embodiment of the invention illustrated in FIG- URES 7, 8 and 9 an improved non-spill bobbin case 200 is shown adapted for use in a suitable loop taker (not shown) of a lock stitch sewing machine, for example, the loop taker 36 of sewing machine 20, which may include a trimming mechanism 202 generally represented in FIG- URE 7 by the hooked ended thread engaging finger.

The bobbin case 200 has an endwall 204 in which is diametrically disposed a pivotable grip 206 on either side of which is formed a rotation restraining aperture or notch 208. An annular flange 210 extends from the outer periphery of the endwall 204 perpendicularly therefrom so that the case 200 defines a substantial basket shape.

The end of the case 200 opposite the wall 204 is open to receive a bobbin 212 therein. The bobbin 212 has an annular hub 214 having an inner circular flange 216 and an outer circular flange 218 connected at either end thereof. A supply of bobbin thread 220 is wound about the hub 214 between the

flanges

216 and 218. The bobbin 212 is free to rotate relative a bobbin case 200, with the axis of rotation substantially parallel to the flange 210.

On the side of the case 200, adjacent the pivot connection of the grip 206, a brake device designated generally 224 is pivotally disposed in the flange 210 of the case 200.

The brake device 224 includes a lever 226 having a combined brake and thread engaging portion or finger 230 formed at one end thereof to extend across the

flanges

216 and 218. The lever 226 is pivotally connected into the flange 210 by an integral pin 232 formed at the other end thereof, with the finger 230 and the pin disposed substantially perpendicular to the end wall 204. The finger 230 and the pin 232 are disposed parallel to the axis of rotation of the bobbin 212.

A tensioning means in the form of a biasing spring 234 is anchored to the flange 210 by a screw 236a, with a second screw 236k turnable in the flange 210 to adjust the biasing force exerted by the spring 234. A free end 238 of the spring 234 engages the lever 226 to bias the brake finger 230 into engagement with the

bobbin flanges

216 and 218. Intermediate screw 23Gb and end 238 the spring 234 has a thread tension portion 240 under which the bobbin thread passes to be guided and yieldably pressed against the flange 210. The flange 210 has a built-up section 242 which carries the brake device 224 and tensioning spring 234. A recess 244 extends on the bobbin side of the periphery of the section 242. The recess 244 has a radial thread exit slot 246 at one end and an enlarged slotted aperture 248 at the other end thereof, each disposed to communicate with the open end of the case 200. Another radial slot 250 is formed adjacent the aperture 248 and spaced therefrom.

The bobbin thread 220 follows a serpentine path through the slots; issuing out of the slot 250 to come into contact with the thread tension portion 240 of the spring 234, passing into the aperture 248 and about and under the lever 226 to come into contact with the thread engaging finger 230, and finally issuing from the slot 246 from which point it may be drawn as need be. The free end 238 of the spring 234 is bent into the aperture 248 to engage the lever 226 and urge the finger 230 into engagement with the

flanges

216 and 218.

Accordingly, the finger 230 of the brake device 224 is normally biased into engagement with the

flanges

216 and 218 of the bobbin 212 and thereby acts to prevent issuance of the bobbin thread 220. However, the finger 230 will be released whenever the bobbin thread 220 is drawn to create a lifting force at said finger 230 which overcomes the biasing force of the spring 234 and results in the lever 226 pivoting as illustrated in FIGURE 9, to release the finger 230 from engagement with the

flanges

216 and 218. So long as the bobbin thread 220 is posi tively fed or drawn the finger 230 will remain out of engagement with the

flanges

216 and 218 thereby permitting the bobbin 212 to rotate and the bobbin thread 220 so as to be fed. On the cessation of the bobbin thread feeding the tension spring 234 will immediately bias the finger 230 into re-engagement with the

flanges

216 and 218 to brake the bobbin turning and prevent over-spilling of the bobbin thread 220.

Once again the force required to effect release of the finger 230 of the brake device 224 is sufliciently small so as not to interfere with the drawing of the bobbin thread 220 during normal sewing operations or the like. Though the finger 230 serves the dual function of both braking and thread engaging, it will nevertheless permit the bobbin thread to remain under substantially constant tension regardless of whether the supply of bobbin thread is full or empty.

In certain applications it may be desirable to pivot the brake device about an axis perpendicular or at an inclined angle to the axis of rotation of the bobbin. The improved non-spill bobbin case depicted hereinafter sets forth a perpendicular arrangement. This and other minor modifications, such as the presence or absence of thread slots upon the case, are intended to be within the scope of the present invention.

In the embodiment of the invention illustrated in FIG- URES 10 through the novel non-spill bobbin case is designated generally as 300 and is a component of a loop taker 302 having a loop seizing beak 304 which prescribes a curtate epicycloidal path as illustrated by the dashed line 306 in FIGURE 15.

The loop taker 302 will be embodied in a sewing machine (not shown) in which the loop taker 302 and a needle 308 form part of the stitch forming instrumentalities of said machine. A more detailed description of the sewing machine and the stitch forming instrumentalities thereof in whch the loop taker 302 is embodied may be had by reference to the United States patent application to which the present case is a continuation-in-part, namely, the pending application for a Stitch Forming Mechanism For Sewing Machines, United States Ser. No. 483,- 696, filed Aug. 30, 1965. Only those components and the operation thereof which need be described so as to provide a complete understanding of the present invention are set forth herein.

The sewing machine (not shown) has a bed plate 310, shown in FIGURE 11, with an aperture 312 therein covered by a throat plate 314 which is formed with a needle aperture 316 and a plurality of slots (not shown) for use by a suitable work feeding mechanism (not shown) of any known variety.

The loop taker 302 of this form of the invention is a shuttle 318 journaled for turning movement in an upwardly open counterbore 320 formed in an oscillating arm 322 fulcrumed on a shoulder screw 324 threaded to the underside of the bed plate 310. A shuttle driver 326 is carried within the counterbore 320 beneath the shuttle and is connected to the top of a shaft 328 journaled in a bore 330 concentric with the counterbore 320 and through the oscillating arm 322. Beneath the oscillating arm 322 a pinion 332 is secured by a set screw 334 to the shuttle driver 328 as illustrated in FIG. 11.

Carried beneath the oscillating arm 322 is a plate 336 formed with an arcuate gear segment 338 arranged to mesh with the pinion 332. During sewing the plate 336 remains stationary relative to the sewing machine frame being secured in position by the fulcrum screw 324 for oscillatory lever 322 and also by an adjustable clamp screw (not shown) threaded to the underside of the bed plate 310 so as to eflect adjustment of the turning of the shuttle relative to the reciprocation of the needle, for optimum loop taking effectiveness.

The shuttle 318 includes the improved bobbin case or basket 300 having a bottom wall 340 with a central stud 342 therein and bounded by upwardly extending walls that terminate adjacent the open top thereof. Formed about slightly more than half of the periphery of the case 300 is an arcuate bearing rib 344 which is journaled snugly in the counterbore 320 of the supporting arm 322 and which is formed at one extremity of the loop seizing beak 304.

As illustrated in FIGURES 10, 12 and 13 the cylindrical case 300 is offset slightly relative to the center of curvature of the annular bearing rib 344 so that the cylindrical case 300 will similarly be slightly eccentric to the axis of the shaft 328. The counterbore 320 extends to the free extremity of the supporting arm 322 providing an opening 346 in the passage through which the loop seizing beak 304 may seize a needle thread loop. A gib 348 is secured by screws 350 over the supporting arm overlies the shuttle bearing rib 344 to constrain the shuttle therein.

The shuttle driver 326 is formed with an arcuate rib 352 which extends between the extremities of the shuttle bearing rib 344 thus to impart oscillatory motion to the shuttle about its central aXis as the pinion 332 is turned in mesh with the gear 338. The shuttle, in addition, is carried bodily by the supporting arm 322 for oscillatory motion about the supporting arm fulcrum 324. The resulting motion of any point on the shuttle is epicycloidal. In particular, the path of motion of the loop seizing beak 304 of the shuttle, since it is disposed at a larger radius than the pinion 332 will partake of a curtate epicycloidal path as illustrated by the dashed line 306 in FIGURE 15. An advantage of the epicycloidal motion resides in the ease and speed with which needle thread loops are seized, manipulated completely about the shuttle, and shed from the shuttle. Indicated at 354 in FIGURE 15 is the loop seizing point along the path of motion of the loop seizing beak, and indicated at 356 is the point along the path of motion of the beak at which the needle thread loop will have been carried completely about the shuttle. Beyond the point 356, the shuttle beak will no longer influence the needle thread loop and the take-up (not shown) will assume its role of drawing up the thread. FIGURES 10 and 11 illustrate the shuttle with the beak position substantially at the needle thread loops seizure corresponding to the point 354 in FIGURE 15. FIGURE 12 illustrates the shuttle with the beak 304 positioned substantially at the needle thread shedding point 356 as illustrated in FIGURE 15. FIGURE 14 illustrates the shuttle at the extreme position of motion with the beak corresponding to a point 356 in FIGURE 15.

FIGURES 11 and 14 best illustrates the bobbin 360 and the provision for controlling the bobbin thread tension. The bobbin 360 comprises a bottom flange 362 and a central hub 364 formed with a blind bore 366 accommodating a stud 342 within the shuttle case or basket 300. A top flange 368 of the bobbin is formed with an annular recess 370 of which the inner diameter is undercut as at 372 to provide a fingernail grip for removing and replacing the bobbin in the basket.

For accommodating the bobbin thread, the shuttle basket 300 is formed with a thread slot 374 leading from the upper edge of the basket to a thread eyelet 376 near the bottom wall 340 of the shuttle.

Above the eyelet 376 the shuttle basket is formed with a recess 378 from which a thread guiding groove 380 extends to the upper edge of the basket 300. Pivoted on a pin 382 on the side of the bobbin case or shuttle basket 300 is a bobbin brake device 384 of which a lower arm 386 depends into a slot in the shuttle base in position contiguous to the rim of the bottom flange 362 of the bobbin. An upper arm 388 of the brake lever or device 384 underlies the thread guiding groove 380 and is further provided with a lateral finger 390 across which the bobbin thread is directed between the eyelet 376 to the thread guiding groove 380. Secured by a screw 392 to the exterior of the shuttle basket 300 is a leaf spring of which an upper arm 394 extends across the upper arm 388 of the brake device and across the thread slot 374, and a lower arm 396 extends opposite the lower arm 386 of the brake device. The action of the spring arm 396 biases the brake arm 386 against the bottom bobbin flange to deter overspinning of the bobbin. In addition, the bobbin thread in passing between the upper arm 388 and the spring arm 396 will be subjected to a tensioning friction. When, however, the bobbin thread is drawn taut diametrically across the bobbin from the thread guiding groove 380 as in the extreme position of the shuttle as illustrated in FIGURE 13, the bobbin thread will apply a counterclockwise turning movement to the brake device 384 as viewed in FIGURE 14 and release both the bobbin thread tension and braking influence on the bobbin.

Such bobbin thread tension release occurs automatically after each stitch has been set and provides a limit on the stitch setting tension applied to the bobbin thread. When the bobbin thread tension is thus released, an increment of bobbin thread equal to that used forming the preceding stitch may be withdrawn from the bobbin free of influence of the bobbin thread tensioning means, and moreover without adversely influencing the preceding said stitch.

In the dot and dashed line in FIGURE 15 designated generally as 398 is indicated the path of motion of the thread guiding groove 380 on the shuttle basket 300. Due to the eccentricity of the shuttle basket the path 398 takes the form of a modified curtate epicycloid. It will be apparent from the path of motion 398 illustrated in FIG- URE 15 that a considerable degree of control is exercised over the position of the slack bobbin thread while the shuttle occupies positions other than the stitch setting position of the FIGURE 13, i.e., since the thread guiding groove 380 partakes of a curtate epicycloidal loop denoted at 400 in FIGURE 15, the slack bobbin thread will be partly taken up during stitch formation, and moreover, said slack bobbin thread by virtue of this advantageous motion will be urged away from the path of the needle.

Accordingly, the novel non-spill bobbin case of the present invention may be embodied in any loop taker, regardless of type, such as a shuttle or rotary hook, or the like.

It will be understood that various changes in the details, materials, arrangements of parts and operating conditions which have been described herein and illustrated in order to explain the nature of the invention may be made 10 by those skilled in the art within the principles and scope of the invention.

Having thus set forth the nature of the invention, what I claim herein is:

1. A non-spill bobbin case for a loop taker of a sewing machine comprising:

(a) a thread carrying bobbin having a hub and at least one circular flange disposed in the bobbin case,

(b) a brake device is pivotally connected to the bobbin case to pivot about an axis parallel to the axis of rotation of the bobbin,

(c) the bobbin case includes an annular flange having slot means therein,

(d) tensioning means carried on the bobbin case to bias the brake device into engagement with the flange of the bobbin and to place the thread under tension,

(e) the brake device includes a thread engaging portion thereof,

(f) the tensioning means includes guide means cooperating with the slot means and the brake device to permit the thread of the bobbin to exit from the bobbin case and passes about the thread engaging portion of the brake device, and

(g) the thread engaging portion of the brake device on drawing of the thread of the bobbin adapted to cause the brake device to pivot out of engagement with the flange of the bobbin whereby said thread may be drawn to form or set a stitch or prior to cutting thereof.

2. The combination claimed in claim 1 wherein:

(a) the brake device includes a lever pivotally connected intermediate the ends thereof to the flange of the bobbin case,

(b) a brake finger is formed at one end of the lever normally to be biased into engagement with the flange of the bobbin,

(c) a thread engaging finger defined by the thread engaging portion is formed at the other end of the lever and on drawing of the thread engaged therewith is adapted to pivot the lever to release the brake finger from contact with the flange of the bobbin.

3. The combination claimed in claim 2 wherein:

(a) the brake finger and the thread engaging finger are disposed parallel to the axis of rotation of the bobbin.

4. The combination claimed in claim 1 wherein:

(a) the brake device includes a lever pivotally mounted to the flange of the case at one end thereof,

(b) a finger formed at the end of the lever remote from the pivotable connection thereof,

(c) the finger normally biased into engagement with the flange of the bobbin, and has the thread of the bobbin in contact therewith on the opposite side thereof from the biasing force of the tensioning means whereby on pulling of the thread the force of the tensioning means is overcome to release the finger from engagement with the flange of the bobbin to permit a supply of bobbin thread to be drawn from the bobbin case.

References Cited UNITED STATES PATENTS 347,804 8/1886 Hubbard 242-128 38 8,323 8/ 1888 Vannett 112-231 1,234,398 7/1917 Schwarzmann 112-98 1,792,238 2/1931 Parkes 112-231 1,995,278 3/ 1935 Kessler 112-228 2,555,658 6/1951 Ritter 112229 2,975,738 3/ 1961 Hoppe 112-229 XR 3,038,429 6/ 1962' Ketterer et al. 112-252 XR JAMES R. BOLER, Primary Examiner