US2436449A - Sewing machine - Google Patents

Description

Feb 24, i948. J. H. PlKus'., j 2,43

SEWING- MACHINE Filed April 19, 1944 4 Sheets-sheet 1 Feb. 24, 48. .1. H. PIKUL.

SEWING MACHINE Filed April- -l9, 1.944 4 Sheets-Sheet 2 INVENTUR: cgw.

EIY

.5, H. PHKUL, I, 436,449

SEWING MACHINE Filed April 19, l944 4'Sheets-Sheet 3 INVENTUR 5mt@ se ,CPM EN ATFYE r J. H. PlKUL SEWING MACHINE Feb. 24, 1948.

.Filed April 19, 1944 l4 Sheets-Sheet 4 ibn/ENTER:

Patented Feb. 24,l 1948 SEWING MACHINE Joseph H. Pikul, West Newton,

'. lhe Reece Corporation,

Mass., assignor to a corporation of Maine Application April 19,1944, Serial No. 531,706

11 claims. (ci. i12-242) This invention relates to sewing machines and more particularly to the thread-handling mechanisms thereof.

It is an imperative requirement of any modern sewing machine that a stitch is being formed with the first reciprocation of the needle in an operating cycle of the machine.l To attain this end, it is customary to provide a thread pull-off which draws extra thread from the thread supply and makes it available to the needle for the formation of the rst stitch, so that the thread end will remain in the work and not be pulled therethrough by the action of the stitch-forming instrumentalities. The conventional thread pulloifs, however, lack control over the extra thread and leave the same dangling on the machine for use by the needle, with the result that at least the first stitch is loose and irregular in appearance as compared with the subsequent stitches.

It is the primary aim and object of the present invention to provide in a sewing machine a thread pull-off which controls the extra thread drawn from a thread supply, to the end that the extra thread provided is at no time appreciably slackened and is made available to the needle substantially at the rate at which the latter requires it for the formation of the rst stitch.

The invention will best be understood from the following description of an illustrative embodiment thereof shown in the accompanying drawings, in which Fig. 1 is a fragmentary side elevation, partly in section, of a sewing machine embodying the present invention.

Fig. 2 is a fragmentary section, taken on the line 2 2 of Fig. 1.

Fig. 3 is an enlarged, fragmentary front elevation, partly in section, of the machine.

Fig. 4 is an enlarged, fragmentary section, taken on the line 4 4 of Fig. 1.

Figs. 5 and 6 are fragmentary side elevations, partly in section, of the machine, showing certain cooperating elements in different positions of operation. f

Figs. 7 to 10, inclusive, are fragmentary side elevations of the machine similar to Figs. 5 and 6, and showing contain cooperating elements in different positions of operation.

Fig. 1l is a front elevation of the looper mechanism employed in the'present machine; and

Fig. 12 is'a front elevation of the same looper mechanism in a diierent operating position.

While the invention is not limited in its appli- Y cation to any particular type of sewing machine, it is for convenience illustrated in connection with a 'button sewing machine of the character shown and described in U. S. Letters Patent No. 2,158,171, issued May 16, 1939. This machine has a base I5 supporting a work plate I6, and an overhanging head I'I in which is suitably guided a needle bar I8, carrying a needle I9 which cooperates with underthread or looper mechanism 29, including loopers 2I and loop spreaders 2I a (Fig. 11), to at-l tach to work W supported on the work plate I6 a flat perforated button B. held by a combined presser foot and clamp assembly C. The construction of the combined presser foot and clamp assembly does not form a part of the present invention, and is for this reason not described in detail herein.

The assembly C is carried by an arm 22 which extends'from a rod 23 slidably secured, as by bearings 24, to the outside of the casing (Fig. 3). The rod 23 carries a pin 25 engaged by a yoke 26, formed in one arm 21 of a lever 28 which is mounted on a rock shaft 29, extending through the head head (Figs. 1 and 2). A torsion spring 30 normally urges the shaft in a counter-clockwise dil rection as viewed in Fig. 1 to maintain the assem-V bly C in its lowermost or work clamping position.'` The other arm 3I of the lever 28 is connected by suitable linkage 32 with a treadle 33. When the treadle 33 is depressed, the lever 28 and shaft 29' in Fig. 1, raising are rocked clockwise as viewed the rod 23 and the assembly C.

The looper mechanism 20 is mounted on a shaft `34, driven by suitable means (not shown) which' oscillates said looper mechanism in timed relation with the needle reciprocations. The needle bar I 8 is reciprocated longitudinally by mechaf nism including a crank 35 (Fig. 2), connected to the needle bar by a link 36. The crank 35 is secured to a needle shaft 3l, driven by means (not shown) which are, or may be, similar to those described in Patent No. 2,158,171.

In the present machine, the thread t passes from a needle thread supply (not shown) to the needle I 9 through a permanent thread tension 38 and a controlled thread clamp 40, as well as through a stitch-setting member 45 on the head r of the machine and a thread tension 39 on the needle bar I8. The thread also passes over pins 4I and 4Ia onthe head I'I. The tension 38 prevents an over-draft of the thread from the supply, land the tension 39 is relatively light and serves to hold the threadv taut between itself and the needle eye. The thread clamp 40 is normally closed to prevent the passage of thread, but is held open during a .part of each work-penetrating I I and journalled in the walls of thestroke of the needle by a cam 42 (Fig. 3) which is carried by the needle crank 35. The cam 42 is adapted to depress a plunger 43 in the wall of the head I1 against the tension of a spring 44 which normally holds the clamp 45 closed. Such depression of the plunger 43 opens the clamp 40 and permits the needle to draw through it an amount of thread adequate for the formation of each stitch. The stitch-setting member 45 is provided at its free end with an eye 46 through which the thread passes, and ls adjustably secured by a screw 41 to one side of the head I? at a point be tween the needle-bar tension 39 and the clamp'40.

In accordance with the present invention, a curved arm 5d is secured tothe outer end of a rock shaft 5I which is journalledina bearing 52 in the head of the machine. A slot or thread passage 53 is formed in a lateral lug 5A of the arm 5B, and a member 55, having an eye or thread passage 56, is adjustably secured to said arm 58 by means of a screw 58 which extends through a slot 51 'in .the member .55 and is threaded in said-arm 50. l

Mounted on the inner endof Vthe rockv shaft 5l is an arm yb5), Vcarr-yinguat its freey end a laterallyy projecting pin B0, normally "adapted to be received ina notch Si in a latch lever 52, pivoted at vE3 to the wall of the head Hand urged in a clockwise direction as viewed in Fig. 1 by a tension spring 154. A laterallyprojecting pin 55 on thelatch lever E2 isfadapted to be engaged by a radial finger -dlsecured on therockshaft 29. A link B1 (Fig. 4) connects thefarm 59 with a lever 58, pivoted at 59 to the head Hof the machine and having intermediate its ends a cam. follower 1.!! adapted to cooperate-with a cam 'H on the needle shaft .31. A suitably7 mounted torsion spring 'i2 (Figs. land 2) urges the arm..5 in a counter-clockwise direction as viewed in Fig. 1 and, through intermediationof the arm 59 and link 67, urges the follower 10. of the lever 68 against the cam 1I.

After the machinehas concluded a sewing operation, the operatordepresses the tread-le 33 so as to lift the assembly C and permit theremoval ofthe work. New work may then beiinserted in the machine, whereupon .they assembly C is lowered byreleasing `the treadle 33. `.in-lifting the assembly C as -described, the finger 65 -on the rock shaft 29 engages the-.pin v6.5 on the latch lever 62 and swingsthelatter from the position shown in Fig. 5-intoY that showninliig. 6,A thereby releasing the pin-,5.9 on the arm ,59 and permitting the arm 5d to .swing from theV home position shown in Fig..5 into-theintermediate position shown in Fig. dwhilethelever `B8 is movedfrom the dot-and-dash line-position into .the full line position shown'in Fig-4,. i. e., into engagement wi-ththe cam li. The swing of the arm v5l! from home position into the intermediate Aposition (Fig. 6) is relativelyV short and insucentto pull extra thread -fromthe supply.

Themachine is nowready to be started, and the cam 1l will, on rotation in the direction ofthe arrow 'Ila (Fig. 4) and during the first descent of theneedle i9 from its uppermost position (Fig. 5) into the'intermediateposition I9' (Fig. l), lowerfthe arm-50 from the intermedlate position shown in Fig. "6 into the lower'- most'position-shownin Fig; 1. ,Whilethe arm 53 is thus rlowered, the thread passage --53 in the latter will draw extra thread from the thread supply through'thetension-33 and to one side of the closed clampA d8, whilethe thread passage 55 in the member 55 will belowered sogasV to permit a partial collapse of the thread between the closed clamp i0 and needle bar tension 39. However, the memebr 55 is preferably so adjusted on the arm 5i] that the resulting slack in the thread between the clamp M) and needle bar tension 39 is created not appreciably in excess of the rate at which the descending needle will use up said slack without withdrawing thread through the needle eye. During furtherdescent of the needle it from the position I9 (Fig. Y1) into the position I9" (Fig. 9), the cam d2 opens the thread yclamp 4i? and the cam H retracts the arm 58 .fromthe lowermost position shown in Fig. 1 into the intermediate position shown in Fig. 9, whereby the. thread passage 53 in said arm 5B releases :the extrathread. previously drawn from the supply to `theopen thread clamp 4B, and said released thread is drawn through said open clamp by the tension 39 and the force with which the thread is frictionally retained on the needle when the same passes. through the work. -W. When the needle i9 reachestheposition l.9" in Fig. 9, the cam #i2 clears the plunger 43 of the thread clamp lidand the latter is permittedto close, with the result that the thread between the clamp 49 and the eye of the needle I9 is, during the last part of .the descent of the needle from the position i9 into the lowerrnost position l9" (see dot-anddash line position in Fig. 9), sufficiently tensioned to assure that a threadloop Z is being cast bythe needle on its following ascent. When theneedle reaches its lowermost position, a substantial length of the threadend beyond the needle eye projects from one of the holes in the button B, and most oithis projecting thread-lengthis subsequently withdrawn through said hole during the seizure and deflection of the loop l by one of the loopers andthe cooperating loop spreader of the loopermechanism 20 (Fig. 10) As the needle [Qascends from itslowermost position into the uppermost position, the needle thread between the workand the stitch-setting` member'4o is merely deected by the needle vbar tension 39 whose .threadclamping force 4is insuicient to draw the thread end through the work. Shortly before the needle reaches its uppermost position, the cam 'H returns the arm 5!) from the intermediate position shown in Fig. 10 into the home position shown. in Fig. 5, whereby the thread passage 56V in the member 55 slightly retracts the needle thread through the eye pf the needle I9 tothe extent that the thread end is withdrawn below the top surface of-the button B but remains in the work W (Fig. l1). -Whenthe arm 5B- isreturned to homepositiornthe latch lever 62 is permitted to return to iatching position (Fig. 5) and the arm 50 is latched in home or inactive positionduring the remainder of the operating cycle of the machine, thoughy its actuating cam H turns with the needle shaft 37 throughout therremainder of said operating cycle. More particularly, the arm 50 is returned to home position when the crest c of the cam H (Fig. 4) is opposite the follower 10 on the lever @3. This cam. crest c is yimmediately foliowed by a cam descent d, the point e of which is opposite the follower 'it in the intermediate position of the cam 'll so that said follower Ymay rise into engagement with the cam point e and permit the arm 5S to move into theintermediate position shown in Fig. 6 on being unlatched in home position when the operator raises the clamp assembly C, as described. While the left hand looper 2l and spreadervzla hold the loop l deflected as shownin Fig. 11, the needle againfde'- Y scends, through the other hole in' the button B, however, and enters the deflected loop l. After the needle I9 has entered the deflected loop l and before it reaches its lowermost position, the looper mechanism 20 is rocked counterclockwise as viewed Yin Fig. 11 until the left hand looper 2| and spreader 2Ia clear the loop l. Thereafter, continued downward movement of the needle I9 into its lowermost position will result in slight contraction of the loop l (Fig. 12) due to withdrawal of thread therefrom by the needle, all the extra thread being used up and the thread between the clamp 40 and the needle being taut at this time. Thus, the loop l is suiiciently contracted to be out of the way of the right hand looper 2| and spreader 2| a when the same seize thev loop vZ. cast by the needle on its following ascent (Fig. 12). The stitch-setting member 45 is so angularly adjusted on the machine head YIT that the thread between the work W and the clamp 40 is, during the last part of the ascent of the needle on each following reclprocation in the operating cycle of the machine, suiciently deiiected by the needle bar tension 39 to impose tension on said thread and thereby set each stitch. Also, after the needle I9 has entered the" deflected loop held by a looper and cooperating loop spreader and before the needle reaches its lowermost position on each following descent, the deected loop is released from its looper and spreader and the needle will then, on continued movement into Ylowermost position, withdraw suiiicient thread from the released loop to contract the latter out of the way of the other looper and spreader which will seize the next loop.

Since the arm 5U is adjustably mounted on the rock shaft 5I, preferably by being clamped thereon as at I (Figs. l and 2) and the mem ber 55 is adjustable on the arm 5D as explained, the needle thread in the machine may, for the successful formation of the first stitch in each operating cycle, be regulated to suit most any conceivable sewing condition. By properly designing the cam 'II and properly adjusting the arm U and member 55, the condition is readily attained where the normally guided needle thread between the thread clamp 40 and the needle bar tension 39 is partly collapsed substantially at the rate at which the needle on its rst descent uses up the resulting thread slack, and the extra needle thread drawn from the thread supply is released to the needle substantially at the rate required by the latter during its continued descent, with the result that the thread in the machine is at no time appreciably slackened and is always under the full control of the stitch-forming instrumentalities. Actual tests on a machine of this type have shown that, on properly adjusting the arm 50 and member 55 and byusing a cam 'Il of proper design, no thread is withdrawn through the eye of the needle during the first descent of the same, except a negligible length during the very last part of the needlejdescent after the clamp 40 is closed and the threadvtensioned to assure the casting of a loopb'ythe needle on its following ascent. Thus, the thread was marked with a pencil at the needle eye, and the pencil mark on the thread did not shift relative to the needle eye in any of the needle positions shown in Figs. 6 to 9, inclusivepwhile the thread in the machine was at the same time observed to be substantially taut.

I claim: y

1. In a sewing machine, the combination with a reciprocatory needle and three successive thread tensioning devices of which one endmost device is movable with the needle and the intermediate device is a thread clamp operable to grip and release the needle thread, of mechanism providing a thread guide between a first pair of devices consisting of said endmost 'and the in-` said clamp is open.

2. The combination in a sewing machine as set forth in claim 1, in which said thread guide and pull-off are relatively adjustable.

3. In a sewing machine, the combination with an eye-pointed needle, means to reciprocate the same including a drive shaft, and successive thread tensioning devices` between said needle and a needle thread supply of which an endmost device is movable with saidneedle, of mechanism to guide the needle thread between said devices, said mechanism being movable from a certain position to slacken the thread between two successive devices of which one is said endmost device and to draw extra'needle thread from the supply through another of lsaid devices, and also movable into said certain position to cooperate with the descending needle in drawing said extra thread between said two successive devices, and a cam on said drive shaft for moving said mechanism from and into said certain position while the needle descends such that the thread between said two successive devices remains substantially taut and the length of the thread end extending from the needle eye remains :unchanged substantially throughout said needle descent.

4. In a sewing machine,^the combination with a needle, means to reciprocate the same including a drive shaft making one revolution for each needle reciprocation, and successive thread tensioning devices between said needle and a needle thread supply of which an endmost device is movable with said needle, of movable mechanism to guide the needle thread between said devices, said mechanism being normally urged from home position into another position to slacken the thread between two successive devices of which one is said endmost device and to draw extra needle thread from the supply through another of said devices, and movable back into home position to cooperate with the descending needle in drawing said extra thread between said two successive devices, a releasable latch arresting said mechanism in homeposition, and a cam on said drive shaft engagedby said mechanism. on slight movement of same from home position into an intermediate position, said cam being adapted during one revolution to control movement of said mechanism from said intermediate position into said other position and then cause movement of said mechanism back into home position.

5. In a sewing machine, the combination with a work support, a liftable work clamp, a needle, means to reciprocate said needle including a drive shaft making one revolution for each needle reciprocation, and successive thread tensioning devices between said needle and a needle thread supply of Whichauendmost deviceis ,movable with saidneedle, omovablefmechanism-to guide the needle. thread. between Ysaid devices, said mechanism .being normally urged from home position into another position to :slacken the thread between two successive devicesiof-which one is said endmost device and to :draw- -extra needle .thread from the supply throughanother of. said devices, and movable back into :home position to draw said extra thread .betweensaid two devices, a movable latch adapted, when Vin operative position, to arrest saidmechanism in home position, a cam on. said .driveshait engaged by said mechanism on yslight movement fof same from home position into Van linter-mediate position, said cam being adapted--duringionelrevolution to control movement of saidmechanism from: said intermediate position into said other position vand then cause movement `of said mechanism back into home position, andmeans to withdraw said latch from operative positionon liftingsaid work clamp and to return said latch intopperative position on lowering said work clamp.

6. In a. sewing machine, :the combination'of -a reciprocating needle :ba-riga needle carried thereby, a releasable .normally `closed thread clamp disposed between the needle and athread supply, a reciprocating tension operative to draw slack thread toward the work while the clamp is closed, and a movable device ,between the thread clamp and needle operative when the clamp is closed to give up thread .to the reciprocating tension as the needle moves toward the work.;I

'7. In a sewing machine,V .the combination with a reciprocatory .need-le, a thread tension movable withsaid needle .andza relea-sable thread clamp between a thread. supply arid .said tension, of ay device normally posltionedsto guide the thread from said clamp to said tension,.said device being movable from itsnormalposition to slacken the guided thread so as :to supplyfpart of it to said tension when said-clamp iszclosed, and returnable to its normal position toscooperate with the descending needle in .drawing thread through said clamp While the latterxisreleased.

8. In a sewing machine, the combination with a reciprocatoryl needle, a thread .tension movable with said needle and .afreleasable thread clamp between a thread supply and said tension, -of a device normally positioned to guide the thread between said tension and-thread supply,said device beingmov-able ,from its normal position to draw yextra thread frcmsaidsupply, and simultaneously slacken the thread between said clamp and tension soias to supply part of it to said tension, when said v,clamp is closed, and returnable to its .normal position .tocooperate with the descending needle in drawing said extra thread through said clamp while the latter is released.

9. The combination in a sewing machine as set forth in claim 8, inwhich said device comprises a thread guide between saidV clamp and tension and .a thread pull-off between said clamp and thread supply.

10. In a sewing machine, the combination with stitch-forming mechanism including a reciprocatory, eye-pointed needle, a thread tension movable with said needle, a releasaole thread clamp between a thread ,supply and said tension, and means for operating said mechanism through a sewing cycle, .of a device normallyv positioned to guide the thread between said tension and thread supply and being movedrin timed relation with said operating means, .first from its normal position and while said vcla-mp is. closed to draw extra thread from said supply .and simultaneously slacken the thread between said clamp and tension so as to supply part of it to said tension when, and at the rate at which, said needle requires thread during .a part of its -rst descent in a sewing cycle without withdrawing thread through the needle eye, .and then back to its normal position tov cooperate with theneedle, still on its rst descent, in drawing said extra thread through said clamp while the latter is released.

1l. The combination in a .sewing machine as set forth in claim 10, in which said device draws extra thread of an amount to replenish the thread between said tension .and clamp onmovement of said device into its normalposition, and to supply said .tension with .the thread required by the needle substantially for .the remaining part of its rst descent .in a sewing cycle ywithout withdrawing thread through the needle eye.

. JOSEPH H. PIKUL.

REFERENCES CITED The following references are of record in the file ofv this patent:

UNITED 'STATES PATENTS Number Name Date 1,983,555 McCann Dec. 11, 1934 2,347,761 Bedard May 2, 1944

Images