US1740380A - Sewing machine - Google Patents

Description

Dec. 17, 929.

H. M. STEPHENSON SEWING MACHINE Filed July l5, 1927 l 1^ Ven bow.' ugh M Steph@ ttOw nsw

A d Illl Patented Dec. 17, 1929 UNITED STATES PATENT OFFICE HUGH M. SITEPHENSON, OF FORT WAYNE, INDIANA, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK SEWING MACHINE Application led July 13, 1927. Serial No. 205,479.

My invention relates generally to sewing machines and more particularly to an im-V proved rotary take-up mechanism therefor.

Rotary take-up mechanisms are desirable, particularly in high speed sewing machines, because of the simplicity of their structure and the absence of heavy vibrating parts. However, these mechanisms have been subject to the disadvantage that the thread has not been positively controlled throughout the cycle of their operation and as a result the thread has been broken or snarled frequently during the operation of the machines. Breaking ofthe thread has usually been accompanied by the ends of the broken thread being wound up in the mechanism which occasions considerable delay and trouble in rethreading the machine. Moreover, rotary take-ups as heretofore proposed have been clumsy in construction and dificult to thread so that they have not been used on slow speed sewing machines of the domestic type, although the fact that they operate with little or no vibration makes them desirable for this purpose.

An object of my invention is to vprovide a rotary take-up which positively controls the thread throughout the cycle of its operation so that the possibility of breaking or snarling. the thread during the operation of the machine will be minimized.

Another object of my invention is to pro vide a rotary take-up of such a construction that in case the thread is broken the ends will not become entangled in the rotating elements of the device. i

Another object of my invention is to provide a compact and simplified take-up mechanism which is adapted for use on sewing machines ofall types.

A further object of my invention is to vary the operation of the take-up in response to changes in the thickness of the material being sewn in the machine.

Further objects and advantages of my invention will become apparent as the description proceeds, and the features of novelty which characterize my invention will be pointed out with part-icularity in the claims having an overhanging arm 11 thereon for supporting a needle-bar 12, presser-,foot 13, and my improved take-up mechanism. The needle-bar and presser-foot cooperate with a loop-taker 14 `and feed-dog 15 in forming stitches in the usual manner during the operation of the machine, and thread is supplied to the needle 12a through a tensioning device 20 and my improved take-up which accurately controls the thread. The needle-bar 12 is operated in the necessary time relation to the loop-taker 14 and feed-dog 15 by a horizontal shaft 16 extending through the arm 11 which is connected by suitable shafts and gearing` to the horizontal shaft 17 beneath the bed plat-e 10 on which the loop-taker 14 is mounted. The stitch forming mechanism, including the take-up, needle-bar 12, presserfoot 13, loop-taker 14 and feed-dog 15, is driven by an electric motor 18 supported underneath the bed-plate 10, although it may be driven, if desired, by a treadle mechanism provided with a belt extending over pulley 19, or by any other suitable means.

My improved take-up mechanism comprises a stationary thread-guide attached to the arm 11 at 2l and 22 adapted to engage the thread at 23 and 24, and a rotatable plate `25 secured to a crank 26 which operates the needle-bar 12 by the connecting rod 27. The needle-bar crank is fixed on the shaft 16, and the v rotatable plate 25 is arranged with its center substantially in alignment with the shaft 16 so that the plate will be substantially balanced. The plate 25 is provided with longitudinally movable threadengaging pins 28 which are arranged in openings 28al in the plate in such relation thereto and 100 the thread-guide as to pass between the thread engaging portions 2', and 24 and engage the thread to complete the stitch in the material beingl sewn and form loops In) (sec Fig. extending from the thread guida. at 23 and 24. After the thread loops SO ha re been pulled out far enough to take-up the amount. oi' thread necessary to form a loop which can be passed around the bobbin case 14 bv the loop-taker 14 and form the suc-A `thread engaging portions 2S and 2t ot' the thread-guide in the direction of' rotation ot the plate (indicated by the arrow in Fig. 2). By this arrangement the pins 28 torni the loops and the springs 31 i'ollow the enlarging'thread loops outwardlxv y thread-guide portions 23 and Qt. The torce exerted by the'follower springs 3l tending to maintain the thread'loops 30 is not great enough to pull thread through the tensioning device 2O or substantially affect the operation of the loop-taker 14, so that when the'thread a.' loops are released the loop-taker straightens the thread loops against the action of the follower springs 31 and brings the latter into alignment with the thread-guide portions 23 and 24. It will be noted that although this construction is not enclosed it accurately controls the thread loops in the take-up, which permits the take-up to be readily threaded, and which minimizes the possibility1 of the thread being broken and beingr wound up on the pins S28 projecting through the rotating plate 25 during the operation of the machine.

In order to provide Jfor longitudinal movement of the pins 28 so that they can be projected and retracted through the openings 2S in the plate' E25., they are mounted on a late 32 which is secured to a sleeve 33 slidable longitudinally on the crank 26. The longitudinal movement of the sleeve 33 on the crank QG, and the corresponding movementsof the pins 28 for moving them so as to engage and disengage the thread in proper time relation to the movement of the looptaker 14, is controlled by a non-rotatable cam 34 which is supported on the shaft 16 and arranged so that it can be angularly adjusted. The cam 34 controls the sleeve 33 and tbe pins 2S by means of a shaft 37 slidably fitted in the bore 2G of the. crank 26,

one end of the shaft 37 having a roller 35 from the action of the cam 3i and the roller 3,5 engilg ing the same as thc latter is rotated about the former b v the movement of the crank Q61 The cam 84 is so designed-that the pins 28 are moved outwardly so as to engage the thread 29 passing through the guide por tions 23 and 24 as they pass-the same, and when the thread loops 30v are pulled out enough to form a loop'which can be passed around the bobbin case 1 5? by the looptaker 14 in the sewing operation the cam 34 retracts the pins 28 releasing the loops. It will now be apparent thatif the cam -34 is shifted angularly the timing of the release of the thread loops 30 from the pins 28 "an be varied to take place when a greater or lesser amount of thread is pulled'out in the thread loops 30.

It is well understood by those skilled in the art that. the4 take-up' mechanism should take up a greater amount of thread when a thick piece ot material is being sewn in the machine than when a thin piece is'being sewn. In order vto do this in my improved mechanism, I connect the cam 34 to the presser bar 13a by an arm 40 which is pivotcd on the cam 34 at 41, so that as the presserfoot 13 is raised above the feed-dog 15 by the passage of material betweenthe presser-foot and the feed-dog, the cam 34 will be moved angularly on the shaft 16 in proportion to the thickness ofthe material. This causes the pins 28 to disengage the thread vloops 30 at a-distance from the guide portions 23 and 24 of the thread guides proportional to the thickness of the material and causes enough thread to be taken up to properly form the stitch and to pass the thread loopv around the bobbin case. p

In'the operation of the sewing machine illustrated, when the rotatable plate 25 is rotated in a direction indicated by the arrow iny Fig. 2 slightly beyond the position iii-which it is shown, the pins 28 are retracted by the cam 34 which releases the thread loops 3U. Upon the release of' the thread loops 30 the needle 12 passes the thread through the material beiner sewn and into engagement with the loop-taker 14'. The loop-taker then passes the thread loop around the bobbin case 14 containing the lower thread and -straightens the thread loops 30 between the portions 28 and 24 of the thread guide against the action of the springs 31. The loop-taker 14 then releases the loop which is around the bobbin case 14a and by-this time the pins 28 are projccted through the plate 25 and rotated so as to engage the thread 29 extending through the portions 23 and 24 of the thread guide. Further movement of the mechanism causes the pins 28 to pull out the thread loops 30 as shown in Fig. 2 and thereby take up the loop around the hobbin case 14 which is released from the loop-taker let. The pins 28 are rotated by the plate 25 until they complete the stitch and take up enough thread to for'm a loop which can be passed around the bobbin case ll by the loop-taker 14 in forming the succeeding stitch. T he amount of thread which is taken up by the pins`28 in this manner in addition to that required to form a loop which will pass around the bobbin case is controlled by the material being sewn which varies the height ot' the presser-foot aboye the feed-dog 15 as the thickness of the material varies and which correspondingly varies the position of the cam 34 and the amount of thread taken up. I

In view of the foregoing it will be clear that I have produced an improved rotary take-up for sewing, machines which accurately controls the thread through the cycle of its operation, which is simple` and compact, and which minimizes the possibility of the thread becoming entangled in the take-up in the event the thread is broken during the operation ot the machine. Y

Although I have shown one form of my invention in connection with an electric rotary center bobbin sewing machine, it is obvious that modifications can be made and that it is applicable as well to other types of sewing machines. I desire it to be understood, therefore, that my invention is not limited to the particular arrangement shown and described, and I intend in the appended claims to cover all modifications which do not depart from lthe spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States, is

1. In a sewing machine take-up, means for guiding a thread, a rotatable element, means for connecting the thread to said rotatable element when the latter is in oneJ position to form a thread loop, means for disconnecting the thread loop from said rotatable element when the latter is in another position, and means movable in a direction opposite to the movement of said rotatable element for guiding the released thread loop.

2. In a sewing machine take-up, means for guiding a thread, a rotatable element, means for connecting the thread to said rotatable element when the latter is in one position to form a thread loop, means for disconnecting the thread loop from said rotatable element when the latter is in another position, and means including a movable spring for guiding the released thread loop.

3. In a sewing machine take-up, means for guiding a thread, a rotatable element, means for connecting the thread to said rotatable element when the latter is in one position to form a thread loop, means for disconnecting the thread loop from said rotatable element when the latter is in another position, and means including a spring tending to move in the direction of rotation of said rotatable element for guiding the released thread loop.

4. In a sewing machine, a take-np including a rotating plate, a stationary thread guide extending adjacent said rotating plate, a pin extending through said plate adapted to engage a thread carried by said thread guide, another plate on which said pin is mounted, and means for moving said plates relative to each other to retract said pin into said rotating plate and release the thread.

5. In a sewing machine take-up, means for forming a thread loop, means for releasing said thread loop from said first mentioned means, and means for guiding the thread loop including a spring tending to maintain the same.

G. In a sewing machine, a take-up comprising two stationary thread guides, means for forming a thread loop extending between said thread guides, means for releasing the thread loop from the first mentioned means, and a movable thread guide provided with a spring exerting such force tending to maintain the loop that the tension of the thread pulls said movable thread guide into alignment With said stationary thread guides and straightens the loop.

7. In a sewing machine, a take-up including a rotatable plate, a stationary thread guide extending across said rotatable plate, a movable thread guide, a spring tending to retain said movable thread guide in a position displaced from said stationary thread guide, said spring exerting such force that said movable thread guide is brought into alignment with said stationary thread guide by the tension of the thread thereon against the action of said spring, means on said rotatable plate for engaging the thread to form a loop therein extending Ifrom said stationary thread guide, and means for releasing the thread after the means for engaging the thread has been displaced from said stationary thread guide, so that the thread loop is straightened and the movable thread guide is brought into alignment with the stationary thread guide by the tension of the thread.

8. In a sewing machine stitch forming mechanism, a needle bar crank, a rotatable member supported by said crank, means carried by said member for engaging a th read. and means for disengaging said last mentioned means from the thread. including an extension through said needle bar crank.

9. In a sewing machine stitch foi-nung mechanism. a needle bar actuating shaft ha ving a crank pin thereon. a rotatable plate mounted on said crank pin, a thread guide adjacent said rotatable plate, pins extending through said rotatable plate for engaging the thread in said thread guide, means for retracting said pins into said rotatable plate for disengaging the thread from said pins including a stationary cam surrounding said needle bar actuating shaft, and an extension through said crank pin.

10. In :1 sewing machine stitch forming mechanism including a presser-bar, a needle bar actuating shaft having a crank pin thereon, a rotatable plate mounted on said crank pin, a thread guide adjacent said rotatable plate, pins extending through said rotatable plate for engaging the thread in said thread guide, means for retracting said pins into said rotatable plate for disengaging the thread from said pins including a stationary cam surrounding said needle bar actuating shaft and an extension through said crank pin, said last mentioned means being controlled by said presser-bar.

ll. In a sewing machine stitch forming mechanism. a needle bar actuating shaft having a crank thereon, means carried by said crank for taking up the thread in said mech anism, and means for controlling the take-A up means including a shaft extending into said crank and a sleeve on said crank connected to said shaft.

In witness whereof, I have hereunto set my hand this 11th day of Julv, 1927.

HUGH M. STEPHENSON.

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