US2688944A

US2688944A - Sewing machine construction

Info

Publication number: US2688944A
Application number: US184027A
Authority: US
Inventors: Peter F Cencer; Whiteman Fred
Original assignee: LEONORE GIDION
Current assignee: LEONORE GIDION
Priority date: 1950-09-09
Filing date: 1950-09-09
Publication date: 1954-09-14
Anticipated expiration: 1971-09-14

Description

Sept. 14, 1954 P. F. CENCER Erm.

SEWING MACHINE CONSTRUCTION 6 Sheets-Sheet l Filed Sept. 9, 1950 BY Fred 81M M@ Sept. 14, 1954 P. RCENCER ETAL SEWING MACHINE CONSTRUCTION 6 Sheets-Sheet 2 Filed Sept. 9 195C 6 Sheets-SheefI 3 P. F. CENCER Erm.

SEWING MACHINE CONSTRUCTION Sept. 14, 1954 Filed sept. 9, 1950 Sept. 14, 1954 P. F. cENcER Erm.

sEwING MACHINE CONSTRUCTION 6 Sheets-Sheet 4 Filed Sept. 9, 1950 TORS. Cene@ BY fred Z//zlzl @7% W 1.@2/@4/0@ man Sept. 14, 1954 P. F. CENCER ETAL SEWING MACHINE CONSTRUCTION 6 Sheets-Sheei'l 5 Filed Sept. 9 1950 IN1/EN ToRS. @2726977 Z/umn,

Sept. 14, 1954 P. F. CENCER ETAL SEWING MACHINE CONSTRUCTION 6 Sheets-Sheet 6 Filed Sept. 9 195C Patented Sept. 14, 1954 UNITED STATES OFFICE 2,688,944 vSE'VVING MACHINE CONSTRUCTION Application September 9, 1950, Serial No. 184,027

This invention relates generally to sewing machines and has to do more particularly with a sewing machine having novel means for automatically taking up the thread in the stitches in the material being sewed for producing tight stitches, and novel means for feeding the material through the machine as it is being sewed.

An object of the invention is the provision of a sewing machine having such novel construction that it automatically draws the stitches tight regardless of the thickness of the material being sewed, without any manual adjustment made for the purpose.

Another object is the provision of a sewing machine in which each stitch, as it is made, is drawn up so that the stitch just previously made is drawn tight, in such a manner that that portion of the previous stitch interconnected -with the subsequent stitch is drawn up into the body of the fabric or other material being sewed, thereby effectively locking the stitches in place so that they cannot easily be ripped out.

A further object is the provision of a rock bar effective for transmitting drive from the driving means to the needle and thread take-up lever, and effective for releasing the thread nipper.

Another object is the provision of a hollow needle bar.

Another object is the provision of material feeding means actuated by a cam on the shaft I which operates the looper.

A more specific object is the provision of a i material feeding means including a feed member moved a fixed, predetermined extent and in a fixed path by the operating parts of the sewing machine, and a second movable feed member, with adjustable means interconnecting the two feed members, whereby the path and` extent of movement of the second feed member can be adjusted according to the adjustment of the adjustable means, the second feed member having a feed `dog for feeding the material through the machine. v

A further object is the provision of a sewing machine of the character above referred to for making chain stitches having novel mechanism whereby, regardless of the tightness to which the stitches are drawn, puckering of the material sewed is prevented.

Other objects and advantages will become apparent upon reference to the following description and to the accompanying drawings wherein,

Figure l is a front elevational view of the sewing machine of the present invention;

Fig. 2 is an enlarged view oriented similarly to 6 Claims. (Cl. 112-210) Fig. 1, but with the portion of the housing nearest the observer removed;

Fig. 3 is a rear elevational view, with the portion of the housing nearest the observer removed; Fig. 4 is a plan view of the sewing machine with the housing removed;

Fig. 5 is a bottom view of the base showing the operating parts mounted thereon;

Fig. 6 is a vertical sectional view taken on line of Fig. 2;

Fig. 7 is an' elevational view of the machine as viewed from the left-hand end of Fig. 2 with the housing in the foreground removed and the housing in the background in section;

Fig. 8 is afview similar to Fig. 7 with the operating parts in the positions assumed during a dierent portion of the cycle of operation;

Figs. 9 and l0 are detail views of members making up the feeding mechanism for feeding the material being sewed through the machine; and

Figs. 1l to 14, inclusive, are semi-diagrammatic views of the needle, a portion of the needle-driving mechanism, and looper in the positions assumed during various stages in the cycle of operation of the machine. l

Referring now in detail to the drawings, the sewing machine will be described in various phases under appropriate sub-headings to facilitate understanding of the structure of the machine and its mode of operation.

The sewing machine illustrated in the present application is of the type that sews chain stitches, i. e., each stitch is looped through the previous stitch made, and includes a needle which penetrates the material being sewed, and a looper cooperating with the needle for looping successive stitches together; however, certain features of the invention are equally adaptable to sewing machines of other types.

Base

The sewing machine includes a base I6 in the shape of an inverted pan, having a table top I8 for supporting the operating parts of the machine and furnishing a surface for supporting the fabric or other material being sewed. The. base IG includes a surrounding skirt portion 20 having foot portions 22- for engaging the supporting surface on which the sewing machine is placed. The under surface of the base is open as will be referred to later. 'I'he top of the base I8 is provided with certain openings for receiving operating parts of the machine, as well as for receiving s securing means for mounting the operating parts of the sewing machine on the base.

Frame for supporting operating parts vided wth an upstanding flange. 32 which is` closely adjacent the right-hand end of themachine.

The second main elementof the; frame con,- sists of a plate element 34' which is provided with a transverse element or flange 35 secured` to the element 24 as by welding or by other suitable means.l The plate element 8 4, is vertically disposed and extends longitudinally of the machine from. the plate element 26 terminating adjacent theI left-hand end of the machine as clearly illustrated in Figs. 2 and 3. It will also be noted that the plate element 34 is supported bythe upright portion 28 in elevated position with respect to the base.

Main drive In thel present illustrative embodiment a motor 38, which may be an electric motor is provided for driving the sewing machine. However, it will be understood that any suitable means for driving the machine may be employed. rI he motor 3S is mounted on the plate element 26 on the right-hand side of the latter and includes a driving shaft 39 on which is secured a driving pinion 48 meshing with a gear 42 mounted on a shaft 84'. The shaft 44 is journaled in bearings, one of which is mounted in the plate element 26 and the other inthe upstanding flange 32, the shaft 134 extending to thev right of the flange 32 and provided on its outer end with a hand wheel 48 for the usual purpose. Also mounted on the drivin-g shaft 44 adjacent the gear 42 isa second gear 48 of lesser diameter than the gear 42, the gear 48j meshingr with another gear 58. The

gears

42 and 58 project through a slot 52 in the top surface of the base of the machine (Fig. The gear 58 is secured to a shaft 54 for rotation therewith, the shaft 54 being journaled in bearings 56 and 584 mounted on the underside ofthe top of the base. The bearing 58 is positioned adjacent a verticalv plate 60 having a flange 82 secured to` the. underside of the base. The plate 6tlsupports the material feeding means as will be referred to in detail later. If desired, belt drive means may be employed instead of the gearing above described, suitable pulleys being provided on the respective shafts and suitable means being provided for producing properly timed drive between the various elements of the driving train.

Needle driveV A rock bar 6,4 (Figs. 2,A 3 and 4) is provided for transmitting the drive from the motor to the needle and certain other parts of the sewing machine. The rock bar 84 takes the form ofA a rigid flat strip, the main portion of which is `disposed on one side of the plate element 34, extending` longitudinally of the machine with its flat side disposed generally vertically. The rock `har 84- includes two laterally extending arms 66 and 88 which are pivoted in lugs 10 and 'I2 ex-L detail later.

ytending substantially at right angles from the plate element 34, the two pivot points, of course, being in alignment. The arm 66 extends through an opening in the plate element tl to the opposite side thereof. A pitman 'i4 is pivoted at one end to the extended end of the arm 88 by suitable means such as a screw "i8 and at its other end is pivotally mounted eccentrically on the gear 48 by means such as a screw 78. Upon rotation of the gear 48 the pitman is reciprocated, result ing in swinging the arm 66 and thereby rocking the rock bar- 54 and swinging the extended end of the arm S8 whichV also extends across the plate element 34 at the left-hand end thereof. The arm 68. serves the dual purpose of reciprocating the needle and forming a thread take-up lever both of which, purposes will be referred to in The extended end of the arm 68 is provided with an aperture 80 (Figs. 7 and 8) for threading therethrough of thread employed in sewing, whereby the arm serves as a thread take-uplever.

Needle and mounting therefor needle mayl be of any suitable known form and is provided with the usual eye at its lower end. The hol-lowA bar 84 is mounted for vertical reciprocation in bearing

sleeves

88 and 88, the former being mounted on a horizontal element 82 secured toV the plate element 34 and the sleeve 8i) being mounted on a turned over element or Jlange 94 also secured to 'the plate element 34.

A stud 98 is fixed-ly secured to the hollow bar 84 at a point between the bearing

sleeves

88 and 88. A pitman or link 88 is secured at its lower end to thestud 96. as by means of a screw Il and pivotally secured at its upper end to the arm as by means of a screw 182. At this point it should be noted that thel point of connection between the pitman 98 and. the. arm 88 is at a position spaced inwardly from the extreme outer or free end to the arm 88 while the aperture 88 is adjacent the extreme end of the arm. Accordingly, the aperture 88, upon reciprocation of the arm 68, travelsa greater distance than the pitman 98,

A presser foot 10,4. for engaging the material seing sewed is in the form of ay forked element having a slot through which the sewing needle is adapted to project. The presser foot itself may take any. desired shape, but the present illustration includes a horizontal portion |05 adapted to directly engage the, material being sewed, and upturned toe portions |08 effective for directing the material under the presser foot. The rear ortrailing portion of the presser foot is provided with, a Ll-shapedi portion having upstanding flanges Hi8 into which extends the lower end of a mounting element lill. A pin IH extends through thejiianges [08 and element l l!) by means 5, The mounting 'element H0 is mounted on a bar H2 as by means of a screw H4. The bar H2 is mounted for vertical reciprocation in bearing sleeves H6 and H8 mounted on the elements A92 and 94 referred to above in connection with the needle bar. Above the element 92 a collar |20 is xedly secured to the bar |2 and a compression spring |22 is compressed between the collar |20 and the upper bearing sleeve H8 in surrounding relation to the bar for urging the shank and the presser foot downwardly.

For the purpose of raising the presser foot upwardly out of engagement with the material being sewed when it is so desired (as when material to be sewed is inserted into or removed from its position under the presser foot), a lever |24 is pivotally mounted on a pin secured tothe collar f |20, the lever |24 having camming surfaces engageable with the element 92 for so raising the bar and presser foot, and 'is also provided with an over-center surface for retaining the shank and presser foot in raised or elevated position when the lever is thrown to the appropriate position.`

Thread feed and control A spool of thread |26 is mounted in an opening |28 in the plate element 34. The means for mounting the spool includes a pin or spindle |30 pivotally mounted on an out-turned lug |32 formed on the plate element 34. The pin or spindle |30 is adapted to be swung outwardly about a vertical axis enabling the spool to be placed thereon and then swung inwardly so that its free end engages the plate element 34 positioning the spool in the opening 28 in such position that the spool extends on opposite sides of the plate element.

The thread |34 is threaded through a plurality of guides |36 xedly mounted on the plate element 34, the guides conveniently being formed of wires secured to the plate element with loops in their extended ends for receiving the thread therethrough. The thread is also threaded through a pull-off nger |38 which is of a shape similar to that of the guides |36 but is mounted on the rock bar 64 and extends through an aperture |40 in the plate element 34. The pull-off finger |38 is disposed between pairs of the guides |36. Upon rocking of the rock shaft the pull-ofi nger |38 is swung vertically, resulting in pulling 01T thread from the spool in conjunction with other elements of the threading means.

A disk tension means |42 is disposed posterior to the guides |36 with respect tol the movement of the thread from the spool to the needle. The disk tension |42 is best observed in Fig. 4 where it will be seen that it includes a threaded shank |44 threaded in an opening'in the plate element 34. A compression spring |46 surrounds the shank |44 and engages a disk |48 which in turn engages a second disk |50, both loosely mounted on the shank and engageable with button |52 on the outer end ofthe shank. The two disks have convex circumferential portions facing each other for easy reception of the thread therebetween. The spring |46 urges the disks relatively into engagement with each other and prevents undue slipping of the thread between the disks, but is of sufcient yieldability to permit movement of the thread o-n application of a predetermined" the sleeve and a washer |63 on the shank. The

spring urges the shank in'a direction to move the button |56 into engagement with the nut ele' ment |62 for nipping or gripping the thread therebetween. The extended end of the shank |58 is adapted to be engaged by a bumper |64 mounted on the rock bar 64 upon rocking of the latter. The bumper |62 may be of any desired resilient material, such as rubber ora rubber-like product. Turning of sleeve |60 produces an adjustment thereof with respect to the plate element 34 for positioning the shank |58 closer to or fartherfrom the bumper |64 for adjusting the timing of release of the nipper.

The thread is inserted between the button |56 of the nipper and nutrelement |62 and when the button is positioned as shown in Fig. 4, it retains the thread against feeding therethrough in normal operation of the machine and when a predetermined force'is applied to the thread, but when a force in excess of the predetermined tension is applied, the thread can be drawn through the nipper. The nipper |54 is released upon downward rocking of the rock bar 64, i. e., upon the bumper |64 engaging the adjacent end of the shankv|58 and thereby moving button |56 out of gripping engagement with the thread.

Posterior to the nipper |54 the thread is passed through the aperture 8x0 in the arm 68 and then through anl aperture in the elementv 82 and nally through the eye of the needle. s

Housing Most of the operating parts thus far described are enclosed within a housing indicated generally at 64 which is made up of three parts. The housing as illustrated in Figs. 1, 2 and 3, encloses all ofthe operating parts that are disposed above the base with the exception of the hand wheel 46, the lower ends of the needle and the presser foot and their mountings. The housing includes a shell section |66 made up of one piece on one side of the'machine and two separate sections |68 and |10 on the other side. 'The portion |66 is secured at' one end to the base as by means of appropriate screws and at the other end to the plate element 34 by screw means |12. The housing section |68 is also secured to the base as by means of screws and the section |10 is secured to the other two sections by means of appropriate clips so arranged that the section |`||l may be readily removed by the operator for the purpose of` exposing certain operating parts of the machine.

Loo/per `Mounted on the shaft 54 on the underside of the base is a small looper indicated generally at |14 for rotation with the shaft. The looper includes a point |16 and a heel-|18. Upon rotation of the looper the point |16 engages a thread loop formed by the needle 82 upon penetration of the needle through the material being sewed. The loop is carried around by the looper and finally cast 01T therefrom but a new loop is picked up before a previousloop has been cast 0E for M ateri'al. feedingv means Mounted on the plate'- element 60 on the underside of thebase is apairlof plates referredtof'or convenience as an auxiliaryfeed member |82 and amain feed member |84. The feed members are preferably fitted with their fiat sides in engagement and both are provided with slots- |86 through which a screw |88A extends, the screw being mounted in theplate-element Sil. The feed members |82 and |84 are therefore mounted for vertical swinging, and forlongitudinal sliding movement. The auxiliary feed' member |82 is providedy with a notch I90'- open` at the top, in which the cam |-80i isdisposed, the horizontal dimension off the notch being substantially equal l tothe-diameter of the-cam. At the free1 or swinging end' off the auxiliary feedmember |82 isa cut out portion |92- inwhich is operativelydis'- posed an enlarged head |94' of' a link- |f96 connected toY an' arcuate lever |98 having a slot 20|) therein. The lever |98` ispivoted at 202 on the plate 60' for swingingv inl a Vertical plane parallel with theplanes-of movement of the members |82 and |84.

The main feed member |84 is' provided with a horizontally arranged slot 204 through which thecam |8|lprojectsr The slot 204 has avertical dimension substantially equa-lto the diameter of` the cam |8'- but has a horizontalv dimension of 'substantially greater extent. A-t the extreme or swinging end ofthe element |84 Vis a cut out portion 265 for piVotally-receiving an enlarged head 2&8 of. alink 2li?, the oppositev end of the linlrhaving a laterally projecting stud` 2|.2` operatively disposed in the slot 200,

A yoke or L-shaped element` 214 (Figsi 5,` 7 and. 8).? isA disposed` with its legs straddling the plate 6|), and feed' members |82' and |84, one of the legs 21'6 being, mounted by means of screw 218k upon the plate element 60T for vertical swinging, rIhe other' leg 220' isprovided with aV di'- agonal' slot 222 (Figs. 7 and 8) for receiving, a pin 22'42on the linkZm;

rlhe leg 21.6` is provided with vertically spaced lugs 226 (Fig. 5) for receiving one arm 228 of `a bell crank lever 23'81 pivotally mounted at 232,

the other arm 234 being pivotally connected at 23.8 toa rod or link 238 extending toward the op? posit'eY end of the base where a thuinbserewand operating. knob 240 are secured and which extend throughv the base as indicated in Figs. land 2 forY manipulation by the operator for adjusting the length of the threads as will' be explained later. The thumbscrew. 2,40 may be turned in to gripping engagement with the base for se-v curingit in adjusted position whereby the material feeding-meansV is retained in adjusted position;

Mounted onthe main feed memberl |84 as viewed in Figs. 7 and 8 is a feedl dog 242-Which includes an arm securedto the member |84 by `means of a screw 244 for angular adjustment of the feed dog. rlhefeed-l dogL extends upwardly and has a horizontal*l portion 246v composed of three segments having gripping-teeth 248. The

teeth 2:48 are: adapted.todextend through slots'll in a plate 2,52 mounted-,over a largeopening in thev top surface of: the base-.andi secured therein as by means of screws; 254'. The plate 25:2'- also includes an aperture for. projection therethrough of the'sewing. needle. The teeth 248 arefadapted tosgrip the materiali being sewed in conjunction with the-presserl foot |06 `for feeding the. material through the machine' as it isseWed.

General operation The driving motorv upon operationT thereof, through the gearing referred to, rotates the'shaft 5t for rotating the looper W4? andi the material feedingmeansthrough the canfrk it; also', the pitrnan'L i4 is' caused'- tov reciprocate, whichv there,.- byrocks the-rock bar Sdi. Upon rocking of the roele bar the armvv 81 is reciprocated vertically and the latter, actingthroug-h pitman- S8; reciprocates the needlebair t4- and the needlev 82?. 'lheY needle projected downwa-rdlyV as shown in Fig. lvl and penetrates through the material being-sewed, which isindioatecl at 256i. A 10011258 isformed below the material and upon rotation of the looper llt as referred to. above. pointrr llt.; thereof projects into the loop and upon continued rotation of the looper, the loop 258` isV carried onto the looper. Further rotation-of; theflooper causes the loopV to, be cast off but before each'. loop isy cast eff, anew loop-isfpleliede uplbyfthe point andcarried through the previous: loopi which is being cast olf. ThisV operation; results in achain stitch indicated generally atit inl ligs. lllk to 14. The material fed through the4 machinebetweeneach two successive stitches for properly spacing the stitches inf the material as willl be described later. y l

Attention is now directed to the novel arrrangement and relationship'rof the parts ofthe sewing machine for drawing the stitches tight; the thread tale-uplever hasfa greater; throwthan the movement of the needle, whereby ay greater amount of linocla'te the` movement of the take-up lever is drawn fromthat portion of the thread making up the stitches, resulting in thefstitches.beingl drawn tight. y

The thread nipper isnormally effective for preventingr paying out. of thread. from the main supply, but it willpermit threaditobe payedout upon suilicient tension being` applied` to the thread;

' for example, the nipper will normally restrain paying out of the. thread so as to effect tightly drawing of a stitch, but thereafter it will permit paying out of thread uponsuicient force being applied to thethread; hence inV the case of thick material. being sewedthe.nipper will effect tight drawing of the. stitches whilefpermitting paying out ofthel greater amount of thread necessary to produce the stitehesas-comparedwith the case of, thin. material, andas a consequence thestitches are drawn tightin materials of all thicknesses without the necessity of manualadjustment made for the purpose.

Upon upward,A rockingvof the rock bar 64', the bumper. |64. ismoved outof engagement with the shank E58' of the nipper |54, permitting the button |56 to` grip the thread; also upon upward rocking of-f'the rock' bar; the-pull-oifA finger |38 swings downwardly and draws thread from the spool |26, this being accomplished by reason of the fact that the thread is gripped by the nipper. As a result, a portion of the thread is payed out for feeding toward the needle at a later step in the operation of the machine. When the arm 68 approaches its uppermost position, the nipper |54 is released upon downward rocking of the rock bar 64 so that the arm 68 forming a takeup lever is enabled to draw up slack in the thread previously produced by the pull-off finger |38, whereby the thread can be payed out or fed to the needle upon downward movement of the takeup lever.

Upon downward movement of the needle the needle carries the thread through the material being sewed, and as the needle is moved downwardly the take-up lever 68 also moves downiwardly permitting slack. thread, previously payed fout bythe take-up lever, to be drawn down by the needle. The stitch is then formed as above described, and upon upward movement of the needle the take-up lever 68 also moves upwardly a distance greater than the upward movement of the needle. During the first portion of the upward movement of the take-up lever the nipper |54 is in thread gripping position, but just before the take-up lever reaches its uppermost position, downward rocking of the rock bar releases the nipper which remains released until after the take-up lever begins its downward movement. Because the take-up lever moves a distance :greater than the movement of the needle, and :also because the thread is gripped by the nipper .in the first portion of the upward movement of 'the take-up lever, the amount of thread neces- ;sary to accommodate the greater movement of `the take-up lever is drawn from that portion of lthe thread making up the stitch in the fabric zand, consequently, the stitch is drawn tight. .During the rst portion of the upward movement of the take-up lever the looper is passing downwardly. In Figure 13 one portion of the looper :in its downward movement is indicated, while fthe take-up lever is moving upwardly, The takeyup lever and the looper coact to draw the thread ltight in the stitch and, in so doing, tension is :applied directly to the strand 268 and the ten- :sion or force applied is transmitted through the ilast stitch made and, finally, into the loop 2i2, Idrawing the latter tight and drawing the bight yof the loop of the previous stitch upward into 'the body of the fabric.` Such condition isshown iat 264 in Figure 14. As a result of such condi- '.tion the stitches are secured in the fabric, and .ripping out of the stitches is rendered difcult.

Special attention is called to the fact that the :free or swinging end of the take-up lever 68 moves fa distance greater than the movement of the needle, and this relationship is effective for drawing the stitches tight, and is in contrast to that arrangement in previously known machines in which the retraction of the needle itself draws the stitches tight.

As mentioned above, the bumper |64 engages the shank |58 just before the take-up lever reaches its uppermost position, and releases the nipper whereby the final upward movement of the take-up lever pays out thread from that portion which was previously payed out by means of the pull-off finger |38. After the take-up lever begins its downward movement, the nipper is again closed for the succeeding stitch.

The arrangement and timing are pre-set for sewing material of the thinnest gauge that may be desired, and with such presetting, materials of any desired greater thickness within a wide range, can be sewed, `without any adjustment being made for the purpose.

The presser foot |84 is in engagement with the material being sewed while the stitch is being formed and, because of the downward pull on the strand 268 (Figure 13), the pressure transmitted to the fabric forces the fabric downwardly against the wide area top surface of the base and this fact, in conjunction with the presser foot bearing on the material, prevents the material from puckering which may otherwise be caused by the tension applied to the thread in drawing the stitches tight.

The means for feeding the material being sewed through the machine is coordinated with the cycle of operation of the machine 'in such a manner that the material is moved while the nipper is released, so that the thread necessary to accommodate the movement of the material is made readily available; the feeding means is adjustable, whereby the extent of movement of the material can be varied for varying the length of the stitches; as a result, stitches will be produced as previously referred to in the case of materials of all thicknesses, with no other adjustment than that necessary for adjusting the material feeding means.

Upon rotation of the shaft 54 and consequent rotation of the cam |88 the auxiliary feed member |82 is caused to follow an essentially horizontal sliding movement. The horizontal sliding movement results in reciprocation of the link |96 to eifect swinging of the lever |98; due to the swinging movement of the lever |98, the free end of the member |82 will have a vertical component of movement, but this will be slight. The swinging mov/ement of the lever |98 causes horizontal sliding movement of the main feed member |84. Also, the cam` causes vertical swinging of the member |84 about the screw |88, and the main feed member |84 therefore has a combined vertical and horizontal movement which follows a path that is essentially rectangular in outline. Upon upward swinging of the feed member |84 the feed dog 246 engages the material being sewed; thereafter, the feed dog is moved horizontally (to the left as viewed in Figures '7 and 8), and in doing so, feeds the material through the machine. After thus moving the material, the feed dog -is moved downwardly away from the material, and then back horizontally to starting position. The feeding action takes place, obviously, when the needle is retracted from the material as illustrated in Figure '7, and this action also takes place when the nipper |54 is released so that thread will be payed out to accommodate the feeding movement of the material. It will be noted that the feeding of the material occurs after each'stitch has been formed and tightened.

For purposes of adjusting the length of stitch the knob 246 is slid one way or the other causing the rod 238 to be moved which actuates the bell crank 238 and swings the yoke 2|4 upwardly or downwardly. The movement of the yoke adjustably positions the stud 2|2 in the slot 200 at respective positions closer to or farther away from the pivot axis 282 of the lever |98. Thus, the longitudinal sliding movement of the plate element |84, and consequently of the 4feed dog 246, is controlled by the position of the stud 2|2, namely, the nearer the pivot axis 282 the less horizontal the movement of the feed dog, and` vice versa. The extent of each increment of the tracted fromfthe materiall `through the machine Vwhile the nipper is open,

preventingpuckerin'g Yof the' materialA during that y operation. Puckering,y of thematerial during the ages-,a4

,feeding movement of thematerialvbeing sewed. is

,controlled and thus the lengthofstitches con- Ltrolled. 'The knob y2.4i] ,can be secured in the tion of the stitch forming' mechanism of the machine operates thesame. forall adjustments of the feedingmechanism, that is, the stitches fwill be drawntight by the take-up lever in conjunctionwith the looperV to the same extent regardless of thelength offstitches. In view of the foregoing in which the various operations and timing relationships were. specifically described, itmay be statedflin. summary that the stitches are drawn tight regardless of the thickness of the material being sewed. The length of stroke of the needle and theextent of. movement of the take-up lever` are vrespectively the same for all `thicknesses of material. `'material each stitch ,is .drawn tight sooner than `in the case of vthin material, `and in the case of In the case of thick thick material the added amount of thread necessary for the stitch is causedf to be payed lout by the take-up lever, which forcibly draws the thread through the nipper veven though the nipper` is in thread gripping position, the nipper permitting thread to be drawn.l for. this purpose due to the by the take-up lever,and (b) the timing between the operations of the elements in the operation of the machine. Thesetwo features result in effective stitch tightening, andv in feeding the material :through the machine .without.puckering; also puckering of the material is prevented during the stitch tightening operation. The ltake-up liever and looper together draw onthe thread to tighten a stitch while the nipperis closed; ifthick matei rial` is-being sewed, vthe `extra thread Ynecessary is drawn [or ,stole'rfy `through the ,closed nipper. rlhisaction v,takes lplacewhile fthe needle is re- The material is fed stitch tightening'operation is prevented because ofthe factthatthevlo'openinits downward movement, is the proximate instrument which tightens the' Stitch as more Vfully explained above.

The operation of ,the lelements is positively timed from a single, main, .positive drive.

vVil'iilfe we have herein shown ,and described a specific embodiment ofthe invention it is to be understoodthat minor changes can be made withl pivotally mounted on ,said supporton a horizontal axis, means for rocking said rock bar, an arm extending laterally from said rock bar, said arm swinging `in ,generally vertical directions on rocking of said rock bar, a reciprocable needle means supporting said `needle and connected with said arm at a point on said varm spaced inwardly lfrom the extended vend of the arm, said needle being reciprocated on swinging of said arm, means guiding said needle for vertical reciprocatlon, means cooperating with said needle for l forming stitches, the extended end of said arm 12 having. an opening `for receiving thread, theA extended end of said arm serving as thread takeup means in cooperation with said stitch forming means.

2. In a sewing machine having a horizontal surface for supporting material to be sewed, and

' means for sewing the materiaL-a pair of platelike members with their flat sides abutting positioned below the material and secured at one end for vertical swinging movement and for horizontal sliding movement, a first one of saidmembers-having a vertical slot therein, a second one of said members having a horizontal slot therein, a feed dog mounted on said second member, single cam means operably disposed in said slots, said cam means being operative for swinging said second member vertically and moving said first member horizontally, alever pivoted adjacent the free ends of said members for swinging in a vertical plane parallel with the planes of movement of said members, means interconnecting said rst member with said lever for transmitting horizontal movement from the member to said lever for swinging the lever, and means interconnecting said lever and saidsecond member for transmitting horizontal movement from said lever, to said second member. Y

3.,In.a sewing machine having a horizontal surface for supporting material to be sewed, and means for sewing the material, a pair of platelike members withtheir flat sides abutting positioned below the material and secured at one end forvertical swinging movement and for horizontal sliding movement, a first one of said members having a Vertical slot therein, a second one of said members having a horizontal slot therein, a feed dog mounted on said second member, single cam means operably disposed in said slots,said cam means being operative for swinging said second member vertically and moving said first member horizontally, a lever pivoted adjacent the Afree ends of saidV members for swinging in a vertical plane parallel with the planes of movement of said members, means interconnecting said first member with said lever for transmitting horizontal movement from the member -tosaid lever for swinging the lever, means interconnecting said lever and said second member for transmitting horizontal movement from said lever `to said second member, and means for adjustably moving the point of connection between said second member and lever toward and from the pvot axis of said lever for varying the extent of horizontal movement of said second member.

4. In a sewing machine having a horizontal surface for supporting material to be sewed, and means for sewing the material, a pair of platelikemembers with their iiat sides abutting positioned below the material and secured at one endfor vertical swinging movement and for horizontal sliding movement, a first one of said members having a vertical slot therein, a second one ofsaid members having a lhorizontal slot therein,

a feed dog mounted on said second member',v

single cam means operably disposed in said slots, said cam means being operative for swinging said second member vertically and moving said rst member horizontally, a lever pivoted adjacent the free ends .of said members for swinging in a vertical plane parallel with the planes of movement of said members, a link pivotally interconnecting said rst member and said lever, said lever having a slot therein, a link pivotally connected at one end to said second member and having its other end slidable in said slot in said 13 lever, and means operative for adjustably positioning the extended end of said link in said slot in positions respectively adjacent to and remote from the pivot axis of said lever for varying the extent of horizontal movement of said second member.

5. In a sewing machine, a frame, a rock bar pivotally mounted on said frame in a horizontal axis for rocking movement, a lateral arm extending from said rock bar and swingable generally vertically in response to rocking of the rock bar, a reciprocable needle supported by said frame for reciprocation vertically toward and from a. sewing station, said needle having operative connection with said arm at a point on the arm spaced inwardly from the extended end of the arm for reciprocation of the needle in response to swinging of the rock bar, the extended end of said arm having an opening for thread and being operative as a thread take-up means, the extended end of said arm having a greater range of vertical movement than the point of connection between said needle and the arm in the swinging movements of the arm, a thread nipper on the side of said take-up means remote from the needle, means biasing said nipper into engagement with thread therein, and means operated by said rock bar positioned for releasing said thread nipper in the latter portion of retracting movement of the needle away from the sewing station.

6. In a sewing machine, a needle mounted for reciprocation toward a sewing station and in retracting movement therefrom, means for supporting a supply of thread for supplying thread to the needle, a thread nipper between said thread supply and said needle, means biasing said nipper to position for engaging thread therein, reciprocable thread take-up means between said nipper and said needle, a rock bar mounted for rocking movement, connections between said rock bar and said needle and said take-up means for reciprocating the needle and take-up means in unison in the same directions in response to rocking of the rock bar, means operated by said rock bar in response to rocking thereof positioned for releasing said nipper in the latter portion of the retracting movement of said needle, and means for rocking said rock bar.

References Cited in the lle of this patent UNITED STATES PATENTS Number Name Date 300,458 Follett July 17, 1884 550,930 Hardy Dec. 3, 1895 827,654 Overdonk July 31, 1906 1,581,524 Wardwell Apr. 20, 1926 2,128,120 Christensen et al. Aug. 23, 1938 2,145,826 Weis et al. Jan. 31, 1939 2,442,647 Fischbein June 1, 1948 2,526,482 Hohmann Oct. 17, 1950