US2725840A - Thread releases for sewing machines - Google Patents

Description

Dec. 6, 1955 F. F. ZEIER 2,725,340

THREAD RELEASES FOR SEWING MACHINES Filed Jan. 18, 1952 4 Sheets-Sheet I B [NVEN TOR WITNESS M g & i edeuicfii g kiew' ATTORNEY Dec. 6, 1955 F. F. ZEIER 'IHREAD RELEASES FOR SEWING MACHINES 4 Sheets-Sheet 2 Filed Jan. 18, 1952 JNVENTOR. mdearz'cic zgeiev WITNESS ATTORNEY 5, I955 F. F. ZEIER 2,725,840

THREAD RELEASES FOR SEWING MACHINES Filed Jan. 18, 1952 I 4 Sheets-Sheet 5 2 A I MIMI IN V EN TOR. iedem'cfi (5. geie r WITNESS y wya W 5 ATTORNEY Dec. 6, 1955 F. F. ZEIER THREAD RELEASES FOR SEWING MACHINES 4 Sheets-Sheet 4 Filed Jan. 18, 1952 ATTORNEY United States Patent Ofiice 2,725,840 Y-Patented Dec. 6, 1955 12,725,840 THREAD RELEASES non SEWING MACHINES Frederick F. Zeier, Stratfield, .Coum, :assignor .to The Singer Manufactu ring v Conjipany, Elizabeth, N. 3., a

corporation of New Jerscy Application January 18, 1l952,-Serial No. 267,129

i l .9 Claims. to]. 11 211-2574 This invention relates to sewing-machine thread con trolling devices andmore particularly to an arrangement forat will minimizingthe frictional drag-imposed by the thread controlling devices on the sewing thread.

[At the completionof a stitched seam and inthe absence of special thread severing :and'holding devices, the

subsequent removal of the work-from the machine-requires that a surplus ofthreadbe drawnfromthe supply.

This surplus thread must be drawn 'through thread manipulating instrumentalities such as thread tensions and thread controlling devices which are adjusted in'a set. position favorable to thedelivery of thread during .thenorrnal stitching operation, but which impose :excessive frictional drag When a greater than normal length .of thread is required. Threadbreakage during removal of the -.work, which'is frequently the result of this exoessive frictional-thread'drag, requires-tedious and time consuming rethreading of theimachine.

It is an object-of this :inventionto provide a mechanism which is efiective when the presser-foot is lifted sfor insertion-and .removal of the work, :toshift certain of the thrcad'manipulating instrumpritalities such as-the thread take-up element's to a relative-position morefavorable to free passageof threadthe'rethrough;

' It is also anobject-to provide a mechanism of the above character which is. -,effcctive to shifter open the hre ft n i n clerncntsito .releaseethe frictional drag exertedupon thezthread-hyithesedevices;

- lating devices ;in inoperative -01": thread-released position,

, Fig. 3 represents a top plan-view ofit'e-thread manipulating devices of :Fig. 2 Iwith thesewing machine frame illustrated-in cross section and with all but one of the thread tensioning devices Lremoved to show the parts ,more' clearly, 4 represents an end elevationalview'of the sewing chine-of F igjl andf" Fig. 5 represents'amenlargedsection taken substantially aI n g linefS S ofFig l illustrating the details of cons uc i nofith eadjta ."relcase.

1 h s .aj. on.t ielevat o ia ,view. of .a. s w n machin ,bg having Q modified fiq iiifp my inventio applie thereto,

Fig- .tepresan aa section (take substant a y lon ,1il ustrati eithed tailsof construction onre as'e Gi t-Fig.6, and

18 r-taraam ntaty 'tfop view- 0f the mechanism '2 of Fig. 6 :for releasing .the thread tension, with the sewing machine frame illustrated in cross section In the drawings, the invention is illustrated as applied to'a two-thread chain-stitch sewing machine. Thesewing machine frame includes a bed 10, from which rises a-vertical standard 11 supporting a bracket-arm 12 which overhangs thebed. A rotary drive-shaft ll'is journaled horizontally in the bracket-arm and is provided with connectionsof the usual type (not shown) for imparting endwise reciprocatory movements to a needle 'bar 13 which is slidably journaled in a vibratory needle-barframehousedin the bracket-arm, the needle-bar carrying aneedle 14 at its lower extremity. A bed-shaft 15'is driven from the drive-shaft 11 by means of a :belt:-16. Supported in the bed and driven from the bed-shaft are the usual lowerstitch-forming and'feeding instrumentalities including a thread-carrying looper 17, a feedsdog l8,.a loop spreader 19, and amovable thread-controlling arm 21. These instrumentalities are similar in details of construction to those disclosed in my prior U.-S. Patent 'No. 2,482,079, September 13, 1949.

Closely associated .with the instant invention is the looper-thread controller including the movable thread controlling arm '21 of which the free ends extends through a clearance aperture 22 in the front portion of the bed and cooperates with a normally stationary thread guiding member23 to engage and control the flow of thread to the looper. As described in detail in another of my prior U. 8. Patents, No. 2,327,838, August 24, 1943, vibratory movements are imparted to the movable arm 21 in a vertical plane by means of an operative connection with the bed shaft .15.

Securedto the upper surfaces of the bed are work supporting plates "25and '26; plate 215 being recessed to accommodate'a throat-plate 27. An alternating pr'ess'er mechanism including apresser-foot 28 and an upper :feedingfoot 29 is operatively supported in the overhangingbracket-arm 12 and spring biasedtoward the throatplate-27 and the lower feed-dogls. The 'presser mechanism illustrated in the accompanying drawings forms the subject of .my copen'ding patent application Serial No. 259,260,'fi'led November 30, land need not be described in detail herein, except as pertains to the means which is provided for.atwill'raisingboth the presserfoot and the" feeding foot; this means beingutiliz'ed to actuate a mechanism for minimizing the frictional "drag exerted on the sewing threads. Ihis'presser-lifting means "includes a bell-crank lever 31 pivoted to the bracketarm. One arm 32 ofthe'leve'r 31 is connected, as-by a chain 34, to any suitablefoot treadle or knee-shift (not shown). A rod 35 pivoted at one end to arm 33 .of the bell-crank-lever fil, issecured at its other end to 'a rock arm'36 which control'sthe movement of the cam7 which. serves to raise and lower the presser mechanism ina manner described in detail in my above mentioned pending application. I

The accompanying drawings, in the interest, of clarity, illustrate only oneneedle and one looper. "It is manifest,

:however, that a plurality of needles and loopers m ay be employed to effect seams having a corresponding number of laterally spaced-lines "of stitching. The friction relieving devices of this invention, moreover, arereadily adapted to accommodate any desired number of'looper threads as will be apparent from the following description; As shown in Fig. l, each looper thread, ofwhich f o supply 7 (not shown) located above and to the rear of the sewing machine downwardly through a vertical tube 39 secured on the standard. The thread one designatcdT is illustrated, is directed thread guiding r i then passed through .a'stationary thread guide 40 to a tensioningfdevice:indicated generally as '41 which in the present embodiment-"is of the type-including a pair of opposed sion disks together with the required pressure.

3 tensioning disks 42-42 arranged on a stud 43 which is threaded to accommodate a thumb nut 44 adapted adjustably to confine a coil spring 45 which presses the ten- From the tensioning device, the looper thread is directed to a thread controller which comprises a normally stationary thread guiding member 23 having a shank portion 50 and an end portion 51 bent into parallel spaced relation with the shank. Aligned thread guiding apertures 52-52 are formed in the shank 50 and end portion 51, thus defining a definite path for the thread as it passes through the controlling device. The previously described movable thread controlling arm 21 is arranged to move in a vertical path between the shank and end portions of the normally stationary guide member thereby to engage the thread and periodically form a loop or bight therein. The free extremity of the movable thread engaging member 21 is, in addition, bent to form a hook 53 which is arranged so that the free extremity of the hook is disposed to engage the thread between the normally stationary control member and the tension device thereby adding to the effectiveness of the thread controller. The function of the thread controllingdevice, it is pointed out, may be varied by changing the position of the normally stationary guideor by changing the timing of the movable arm with respect to the looper by altering the timing of the thread controller driving connection with the bed shaft. According to these adjustments the thread controller may function either as a take-up, a stitch-bystitch pull off, a control device for determining the elasticity of the resulting seam, or a combination of these functions. The thread is directed from the thread controlling device to the looper 17 by means of thread guides 54 and 55 secured to the bed.

As best illustrated in Figs. 1 and 4, a needle thread tension device, indicated generally as 61, is secured to the bracket-arm 12. The tension device 61 is of the well known opposed disk type similar to that of the looper thread tension device described above, and it includes opposed tension disks 62-62 arranged on a threaded stud 63 which is provided with a thumb nut 64 adapted adjustably to confine a coil spring 65 in position to bias the tensioning disks together. The tension device 61 also is provided with a release pin 66 which is slidably journaled in the stud 63. The stud 63 is slotted, as at 67, and provided with a collar 68 arranged between the tension disks 62-62 and the coil spring 65. The collar 68, in a manner well known in the art, is formed with a diametrically arranged web (not shown) disposed in the slot 67 and by which the force of the spring 65 pressing the tension disks 62-62 together may be released in response to movements imparted to the pin 66. In order to affect this tension-relieving movement of pin 66, a curved cam-member 59 is secured to arm 33 of the presserlifting crank lever 31. The cam-member is arranged to contact the push rod 60 which is journaled transversely in the bracket-arm 11 so as to contact the release pin 66.

In the present invention, the normally stationary threadguiding member 23 of the looper thread controller is secured to a boss 70 formed at the extremity of one arm 71 of a bell-crank lever 72 which is secured by means of the pivotal connection 73 to the front wall of the machine bed 10. In Fig. l, the bell-crank lever 72 is illustrated in sewing position in which the thread guide 23 is operatively disposed in a position in which the movable thread-engaging arm 21 engages the thread T and in its downward movement draws out sulficient thread to properly influence the seam characteristics at the stitch ing point as described above. The sewing machine is provided with an actuating linkage which is connected at one end to the presser lifting lever 31 and at its other end to a second arm 74 of the bell-crank lever 72 such that when the presser-lifting lever is depressed, the bellcrank lever 72 is turned in a counterclockwise direction as viewed in Fig. 1, thus shifting the thread guide -23 to 4 a lowered position as illustrated in Fig. 2. In this lowered position of the thread guide 23, the path of the thread through the thread controller is straightened to more closely approximate a straight line regardless of the position of the movable thread-engaging arm 21, and thus the frictional drag on the thread due to the normally devious path through the thread controller is minimized. For purposes of comparison in both Fig. l and Fig. 2, the movable thread controller is illustrated in the same point in the cycle of movement.

The linkage connection between the bell-crank lever 72 and the presser lifting lever 31 comprises a two-part push-rod of which the upper part is pivoted to the presser-lifting lever 31 and the lower part 81 is pivoted to a transversely arranged lever 82 which is pivoted at 83 to the bed and maintained in proper position on the bed by a slotted guide bar 84. The parts of the push'rod are slidably joined by means of spaced slide collars 85-85, the upper collar beingsecured to the upper part 80 of the push-rod while the lower collar is secured to the lower part 81 of the push-rod. A coil spring 86 is arranged on one part of the push-rod between the slide collars 85-85 so that the motion imparted to the thread controller is a gradual yielding one and no binding of parts or breakage can occur should the movement of the presser-lifting lever exceed that desired for the maximum shifting of the thread controller. A stop-collar 87 is secured to the upper part 80 of the push rod so as to insure positive positioning of the actuating linkage in normal operative position when the presser-foot is lowered. Pivotally secured to the front wall of the machine bed 10 is an intermediate bell-crank lever 90, of which one arm 91 is bifurcated to accommodate the transverse lever 82. A second arm 92 of the intermediate bell-crank lever is arranged substantially parallel with the second arm 74 of bell-crank lever 72, and the extremities of these arms 92 and 74 are connected by means of a link 93.

As the presser-foot lifting lever is turned and the needle-thread tensioning device and looper-thread controller are shifted to positions in which these devices exert a minimum of frictional drag on the thread as described above, provision is made in the present invention for simultaneously shifting the looper thread tensioning devices to an inoperative or open position in which a minimum of frictional drag is imposed on the looper thread. Figs. 1 through 5 illustrate one preferred form of construction and arrangement of parts by which this simultaneous friction release on the looper thread is attained. In this embodiment, the tension devices, indicated generally as 41, and the thread guides 40, one for each tension device, are secured to a supporting bar 101. As best illustrated in Fig. 5, the bar 101 is formed with countersunk apertures 102 to accommodate the tension studs 43 in place on the bar. The supporting bar 101 is secured to the sewing machine bed 10 by fastening screws 104-104 and by means of spacing collars 105-105 which serve to position the bar 101 in spaced relation to the bed in order to provide clearance for the actuating link 93. Each of the spacing collars 105 is formed adjacent the supporting bar 101 with a portion of reduced diameter which provides a shoulder 106 opposite the supporting bar 101. As best shown in Fig. 2, a slide-plate 107 is formed with elongated apertures 108-108 each of which accommodates the reduced portion of one of the spacing collars 105-105. The slideplate is thus slidably confined against the supporting bar 101 by the shoulders 106 of the spacing collars. Se cured to the slide-plateadjacent each thread tension device 41 is a U-shaped bent wire tension-opening member 110 which is arranged to straddle the tension supporting bar 101. Fixed to the slide-plate 107 is a driving pin 112 which is embraced by the bifurcated extremity of a third arm 113 formed on the bell-crank lever 72.

Figs. 1 and 4 illustrate the relative position of parts when the presser-foot is, lowered 'as during thesewing plate is formed with" amen operation ofthe machine. In thisposition, thezarm :oflthe,presser-lifting leverlllislra'sed and the flca mi9 is \turned ,to release the push rod ,6

,position, .both the intermediate b,ell-. .cr a'n k' 1'90 and the three-armed lever 72.are :turn'ed in, a clockwise direction to thegreatest extentpossible and,-,.consequently, the ,nor- ,mallystationary thread gui'de 23"of lthe thread controller is raised to operative position and the slide plate' l02 is shifted to ,a position in which the wire .tension-opening members 110 disengage thetehsiondis"ks "When the armsz 0f the" pressfi-"fodtflifting lever is depressed to lift the -presser-fc'io't, the cam '59 serves to shift the push rod 60 to relieve thepressureof the spring '65 from the needle thread' tension' disks 62-62. "By means of'thecollars85-85 and the spring 86, the rod 8 1 is gradually depressed and through the lever ,82, the intermediate bell-crank I90 and the connecting link '93, the three-armed lever 72 is .turnedin a counterclockwise direction. The normally stationaryithreadguiding member 23 of the thread controller is depressed o straighten the thread path, and'the slide plate 'and'tension opening .wires are moved' so as to force'thetensiondis'k's apart .as shown in Figs. 2 a'nd3.

.Figs. 6, 7 and .8 illustratea modified form of my invention which is especially'suitable ina machine which has a'larger number of needles andconsequently a larger number of looper threads.

'Principally, the differences in construction-between this;mo'dified formjan'cl the above discussed embodiment occur withirespe'ctto Lthe looper thread tension devices and the jmeans'i'for relieving the frictional drag imposed thereby. I

In "the modified form, iten "on devices indicated generally as 120, togetherfwiths' ftionaryfthreadrguides 1 cnre'dffto ;the machine "b screws 1244124, and is'spaced from" thef'bed10'hy'spac- .ing collars 125%1'25. Each tension device 120 comprises a stud 126 and a; pairoffopposed'tensiondisks 1'27I27 biased together by means of {a coil spring 128 which is maintained on'the stud by'athumbnut 129. The tension device 120 is similar to the needle i'threafd fterrs'ion device 61 described abovein that there'isprovidefd atensionJrelease "pin 130 slidablyfiournal ed in the studf126; -A

collar f131"is arranged between "the" tension disks and f the Coihspiing and provided with a-diametncally arranged web 132 disposed in a slot 133 formed in thesupporting stud 126. Therelease pin ,130 isadapted to engage the web 132 and thereby'corfipress the-spring 128t'o relieve the frictional :drag which is tnorm'ally imposed on the thread. In order that the looper thread tension-.may .be released simultaneously with the 1' ing of thefli lessen foot, the tension supporting "plate 12 provided atgeach side with a 'pair ofs'p'aced hing knuckles 134 134. Similar hinge knuckles 135135 are formed to extend from the tension release plates 136 and 137; the knuckles 134 and 135 being pivotally secured together by means of binge pins 138138.

One of the tension release plates 137 is provided with coil-spring connections with the machine frame, each connection including a fastening screw 139 threaded into the release plate and a similar fastening screw threaded into the machine frame. Secured between the fastening screws 139-139 is a coil spring 140 which serves to bias the release plate out of operative contact with the tension release pin 130. The other tension release plate 136 is provided with a cam-follower projection 141 which is arranged in the path of a cam surface 142 formed on a block 143 which is secured by slot and screw connections 144 for limited adjustment on a connecting link 145 beillustrated in operative position suitable .for, sewing ,vvith .the-presser-ifoot lowered. As'themresser-footds raised it will be appreciated that connecting :link .1145 ;will he moved toward the right-as viewedinFigs. 6tand 8. {Elie cam surface 142 will turn .the tension release plate 136 about the hinge pin 138 and by virtue of theint connecting extension disks l50 150, .thecamactuated movevment of plate .136 is imparted to release, plate 137 so that vvthe plates 136 and .137-simu ltaneou'sly bear-against .thetension release pin l3iitoirelease the tfrictional drag on thelooperthreads.

Havingthusset forth thenatureofitheinvention, what I ,clairnt herein is:

1. :In a sewing machine a pressenfooband aypresser- .foot ,lifting mechanism, a thread -,con troHing gdevice including athread engagingrnember driving connections between said sewing machines and said thread gengaging lilembermp t n a pr t rmi e an e r Q me smes to said member; and a complement-abnormallystationary thread guidingmember, spacedthread embracing-guides carried by said thread guiding member, said-guides eing normally disposed on;opposite;sides of rsaid thr ea ngaging member to direct;the thread into vthe-range of movement of said thread: engaging member, and. means for shifting said stationary thread guiding member rheyond the range'of movementJof said thread engaging member comprising a linkage carriedtby said sewingnna- -'chi'ne-and connecting. said presser-f ootv lifting mechanism said thread guiding member. V

' 2. 111a sewing machinehaving atpresser-foot and, a presserefoot lifting mechanism, a thread-controlling de- :v icei including a normallystationary thread. guiding memtheir and ,a. threadlengaging. member complementall to each othen said threadtgniding memberhaving spaced-thread controlling surfaces, said thread engaging memberdriven in timed relation with said sewing mah ine betweent'wo ,e xt reme positions on a path. extending. between saidtthread controllingtsurfaces to eifect afsinu o uslthread path of varying amplitude, .7 a linkage connecting -sai d ,nor mallly stationary thread i guiding member .with said ,presserefoot lifting n iechanism, said linkage being 1 operative wh en saii P esser footis lifted to shift saidnormally-stationary ,thread controlling surfaces beyond one extreme .piositio n of said thread engaging member to 'eifect ;a -re,duc t ion of the, amplitude; of said sinuous thread;;path.

3. In a sewing machine having thread manipulating instrumentalities including a spring-loaded thread tension device and a thread controller having a normally stationary thread guiding component, and a thread engaging member driven from said sewing machine so as to effect a sinuous thread-path of varying amplitude, means for reducing the frictional drag imposed by said instrumentalities on the thread comprising, a tension release member shiftable to a position in which said member assumes the spring-load of said tensioning device, an actuating linkage for said tension release carried by said sewing machine, and a supporting member for the normally stationary thread guiding component of said thread 111 thedrawings, the parts of the modified .fform are path-is reduced itrunisQnwith the spring-load accommo- "datingmovement of said tension release member.

4. In asewing'machine having stitch-forming'instrumentalities, a presser mechanism, and a resser-lifting mechanism carriedby said sewing machine, a threadcontrolling device including a three-armed bell-crank lever pivoted to said sewing machine, a normally stationary thread-guiding member secured to a first arm of the bellcrank lever, said thread-guiding member having spaced thread-guiding apertures, a thread-engaging element movable in a path between said thread-guiding apertures, an actuating linkage connected at one end to said presserlifting mechanism and at the other end to a second arm of said bell-crank lever, one or more thread tension devices secured to said sewing machine, a tension-release i plate endwise slidably supported for movement relative to-said thread tension device, and an operative connection between said tension-release plate and a third arm of said bell-crank lever.

5. In a sewing machine having stitch forming instrumentalities,=a presser mechanism, and a presser-lifting mechanism carried by said sewing machine, a threadcontrolling device including a normally stationary threadguiding member and a movable thread-engaging member,

an actuating linkage operatively connected at one end to said resser-lifting mechanism and at the other end to said normally stationary thread-guiding member to shift said thread-guiding member to a position more favorable to free passage of thread therethrough when said presserfoot is lifted a thread tension device comprising a support bracket secured to the sewing machine, one or more pairs of opposed tension disks supported on said bracket, a tension-release plate hinged to said bracket, and an operative connection intermediate the ends of said actuating linkage'with said tension-release plate.

6. In a sewing machine having a presser-foot, a presser foot lifting mechanism and thread manipulating instrumentalities including a spring loaded thread tension device and a thread controller having a normally stationary thread guiding component and a movable thread engaging member, meansfor reducing the frictional drag imposed by said instrumentalities comprising a tension release plate shiftable to assume the spring load of said tension device, a support for said normally stationary thread guiding component, said support shiftable to position said component beyond effective range of said movable thread engaging member, an actuating linkage, means connect- -ing said actuating linkage to said presser lifting mechanism and to both said tension release plate and said support member to shift said parts simultaneously into tension releasing position in response to presser lifting movement, said linkage including a connection having interengaging surfaces arranged to effect a' positive repositioning of said thread manipulating devices into operative position when said presser foot is lowered and a spring arranged to yieldingly transmit said frictional drag releasing movements.

7. In a sewing machine having stitch-forming instru- 8 mentalities, a pressenmeehanism and a presserlifting mechanism, a thread-controlling device including a thread-engaging member driven in a predetermined closed path in timed relationship with said stitchforming instrumentalities and a thread-guiding member having spaced thread-guiding apertures disposed in cooperative relationfwith said'thread-engaging memher, said thread-guiding member supported on saidsewing machine'for movement between a first position in which said spaced thread-guiding apertures are disposed one at each side of thepath ofmotion of said threadengaging member and a second po'sitionin which both of said apertures are disposed at one side ofthe path of "motion of said threa'd-engagingrnember, and a linkage connected at one'end to'said'presser lifting mechanism and at the other end to said thread-guiding member, said linkage arranged to shiftsaid'thread-engaging member 'into said second'position when said presser-foot is lifted and into said first position when said resser-foot is lowered.

8. A thread-controller for a sewing machine comprising, a thread-engaging member driven in a predetermined closed path and a thread-guiding member having spaced thread-guiding apertures associated therewith, said threadguiding membersupp'orte'd on said sewing machine for movement between a first position in which said spaced thread-guiding apertures are'disposed one at each side of the path of motion of said thread-engaging member, and a second position in which both of said apertures are disposed at one side of the path of motion of said threadengaging member, and a manually operable linkage connected at one end'to said thread-guiding member, said linkage arranged to shiftsaidthread-guiding member into either said firstor said second position at the will of the sewing machine operator.

9. Thread manipulating instrumentalities for a sewing machine comprising a thread 1 tension device having a spring loaded operativeposition, a thread tension release member'shiftable to assume said spring load, and a thread controller comprising spaced-thread guides, a movable thread guide supporting member, and a thread-engaging arm reciprocable in apath'between said thread guides, means shifting said tension release member to assume said thread tension spring load and simultaneously, shifting said thread guides with respect to the path of said reciprocable thread-engaging member, said means comprising a manually operated "linkage connected to said thread guide supporting member, and an operative interconnection between said thread guide supporting member and said thread release member to synchronize the shifting of said members.

References Cited in thefile of this patent UNITED STATES PATENTS 1,166,037 Barron Dec. 28, 1 915 1,234,322 Finch July 24, 1917 1,792,387 Moffatt et'al Feb. 10, '1931

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