US2440811A

US2440811A - Blind stitch sewing machine

Info

Publication number: US2440811A
Application number: US350360A
Authority: US
Inventors: Schifter Joseph; Henry L Burkitt
Original assignee: Individual
Current assignee: Individual
Priority date: 1940-08-03
Filing date: 1940-08-03
Publication date: 1948-05-04
Anticipated expiration: 1965-05-04

Description

May4, 1948. J. SCHIFTER ET AL BLIND STITCH SEWING MACHFENE 6 Sheets-Sheet; 1

Filed Aug" 3, 1940 @2 35 ow T R n Om. STE. v mm ww 2d. 0 R a; B QM 8 U 3 WP .mx H0 m n J n m n n i u W. u \u a ow L y 1948. J. SCHIFTER Er AL BLIND STITCH SEWING MACHINE Filed Aug. 5, 1940 6 Sheets-Sheet 2 INVENTORS I HE/IRYLBURK/T'T BY JOSFPH SCH/F75? M 6 625m ATTORNEY I J. SCHIFTER ET AL BLIND STITCH SEWING MACHINE May 4, 1948.

6 Sheets-Sheet 3 Filed Aug. 3, 1940 INVENTOR5 HENRY L. Bun/n 1 BY JOSEPH SCH/FTER ll TTORNE Y y 4, 8- J. SCHIFTER El AL I 2,440,311

I BLIND STITCH SEWING MACHINE F iled Aug. 5, 1940 f 6 sheets sheec 5 INVENTORJ HENRY L. BURKITT BY JOSEPH SCH/FTER 'C @wkdt, ATTORNEY Ratentecl May 4, 1948 BLIND STITCH SEWING MACHINE Joseph Schifter and Henry L. Burkitt, New York, N. Y.

Application August 3, 1940, Serial No. 350,360

22 Claims. 1

This invention relates to blindstitchsewin machines.

In the particular field of blind stitch sewing machines, manipulation of a garment as a seam passes the stitching zone is of considerable importance. Such machines usually have an uprightfrom which extends an arm carrying some of the stitch-forming means. Very long arms have been used on occasion so that cloth of considerable width may be fed Without interference from the upright. That same machine must be capable of working upon small articles.

It is an object of the invention to provide a blind stitch sewing machine having a stitching zone so defined that the machine is capable of coping with the stitching of articles of varied dimensions.

The support for material being stitched is likewise of importance in I such machines. In a simple sewing machine, a stationary table is provided, and only a presser foot is manipulated to hold the fabric during stitching, or to release'the fabric. In the type of blind stitch sewing machines to be considered here, the movements of the needle and the other mechanism cooperating with the needle make requisite that the presser foot be fixed and stationary substantially at all times. It thus becomes necessary to manipulate other parts ofthe machine to effect positioning or removal of fabric from'the machine.

It .is an object of the invention to provide a machine wherein means for supporting fabric to be stitched is capable of manipulation for retaining or releasing the fabric by I simplified means, and wherein such supporting means make possible a high degree of mobility of the fabric while it is being stitched. I

In the usual blind stitch machine, a table of substantially considerable extent. is. provided. Such table supports the fabric, and must be moved relatively to the presser foot in adjusting the fabric that is being stitched. This results in lessened mobility, and reduced speed of operation even when working upon small pieces.

It is an object of the invention to reduce the extent of the movable table so that greater flexibility of operation will be attained. At the same time, it is made possible to enclose substantially all the mechanism for operating the table within a very small portion of the interior of the machine, and particularly of the table, without reducing the efiiciency of the mechanism.

Blind stitch sewing machines usually operate by forming a bight in cloth toibe stitched, the bight being a bend through which the needle passes so that the stitch enters and leaves the fabric at the same side of the fabric. Therefore, some form of bender, plunger or other bightforming means is utilized. .Such bight-forming 5 means must operate in timed relationship to the needle and the other stitch-forming members,

and at the same time must not interfere with the feeding action of the machine. Such bightforming means usually receives its operating force from the same driven shaft as drives the needle and its associated members. In such a machine, all of these driven members, if exposed,

become a source of danger, requiring guards to reduce such danger to an absolute minimum.

It is an object. of the invention to provide a machine of the type indicated, in which bightforming means is operated directly from the usual drive shaft, andyet substantially all the parts of the bight-forming means are housed completely out of suchrelationships as might be dangerous to an operator.

One of the types of stitching usedin the clothing industry is commonly known as bluff edge, or bluff stitch. In such case, the stitch is produced to extend transversely between two immediately contiguous faces of fabric, whether so positioned by folding one piece of fabric, or by superimposing one piece of fabric upon the other.

In any case, the stitch is housed completely between the two fabric faces, and is not apparent at the outer, exposed faces of the stitched-together fabric pieces. Such line of stitching g nerally is spaced away from the edges of the fabric faces so retained, serves to retain the fabric faces substantially in fixed relationship to each other, and yet does not showany seam at the outside of thefabric. Such a seam serves to prevent the two faces from moving relatively to each other. The pieces may, in fact, be secured together at associated edges, and by other stitching; in such a construction, the bluff? seam serves to anchor the pieces together, to prevent the application oflany, strain upon those edges, and? thus to prevent those edges from becoming displaced in their position in agarment where, in fact, they usually define an edge for the garment. j Q

Bluff edge. seams areused generally in connection' with fabric which is quite heavy; manipulation of the fabric in such machines presents a considerable problem. Merely to push all of the layers of. fabric at one time into the path of the needle, as is the usual casein blind stitching, is not'desirable, since this might involve thicknesses 65 produced by folded layers. Without considering known to those skilled in theart, may transmit oscillating movement to ashaft 28 mounted in sultable'bearings in head 26.. 1' An .end of shaft 28 extends beyond head.26 .to' havea needleoarrying. arm 36-securedthereto; By means of a suitable lclamp, an arcuately shapedneedle '32 may be removably fixed to. the end of thearm, the arrangement being such that; as shaft '28 oscillates, point '34 of theneedleeand, therefore, thread 36 carried thereby,will move. through an arcuate path. Shaft 24,, where :it extends beyond arm I4 and into needle head 26, also carries means for imparting both oscillating,rotary and lateral motion. to a looper rod .38 at the end of which is aflixed a looper46, all .of this mechanism being similar'to that of the conventional Dearborn machine. Shaft 24 also has means for imparting motion to a feed dog bar 42 at the end of which is affixed, aifeeddog 44, so that the feed ,dog likewise may-be oscillatedin timed relationship ,to both needle andlooper;

All of these parts operate immediately above or inslots provided in the. usual stationary presser foot 46 of the, Dearborn typefmachine. The presser foot is fixedlymounted upon the end of needle head 26. Dog 44 is lifted and lowered and slid lengthwise within a slot 48 in the presser foot, the slot forming a guide for the dog, and permitting the dog to be lowered into engagement with platens 56, which are carried by arm 52. These platens may be of usual construction, their top faces 54, when fabric is notpositioned thereon and when dog 44 is lifted in slot 48 outof engagement with the platens, being engagedagainst bottom face 56 of the presser foot.

It is necessary to mention generally that, as shaft 24 rotates, feed dog 44, by reason of the manner in which :bar 42 is pivoted and hung, all of which forms no part of the specific invention here, is lifted and lowered, and also is advanced and retracted, that is, follows the usual four motions of a feedingmember, so that its teeth engage with fabric retained between foot '46 and platens 56. Thedog pushes down against this fabric and against the action of the platens, to release the fabric from engagement with bottom face 56. Then, as the dog continues to move, now with lengthwise motion, it drags the fabric over top faces 54 of the platens, and thus feeds the fabric, At the end of its travel, the dog moves upwardly out. of engagement with the fabric, permitting the fabric to come to rest as the platens again press the fabric into engagement with bottom face 56. v Needle -32 now carries thread 36 through the fabric and through a bight formed therein by'one of the bightforming members '66 and 62, to provide a loop for engagement by looper '46, the looper functioning in thenormalmanner to draw the loop over into position for engagement by needle 32on its next stroke. I s

Arm 52, associated with base I6, and supporting platens 56 and

members

66 and 62, is, in the particular instance shown, narrow, its width being just sufficient to house and retain platens and bight-forming members in desired association. Positioned, in its normal position, immediately below. presser foot 46, arm 52 includes a base or mounting section 64 from which a pair of

parallelwalls

66 and 68 extend forwardly and then upwardly. These walls, in the forwardly extending portions and in part of the upwardly extending portions, are connected by a transverse Wall 16, which imparts the necessary. rigidity to '6

walls

66 and 68. Small portions12ofwa1ls'66 and 68 extend beyond the upper edge I4 of wall 16. Toward the (front of portions 12, a pin 16 extends between the portions, andserves as a mounting upon which to pivot platen-carrying arms 18. Arms 18 may take somewhat the form ofbell cranks, being provided bearing sections 86 positioned upon pin I6, the extent of the bear- 7 ing sectionsbeing such that they fit snugly between

walls

66 and 68. I

Arms I8 include fingers 82, extending'in the directionof feed, and having pivots upon which platens 56 are mounted. Otherfingers 64 extend downwardly from sections 86to be engaged with suitablesprings 86 which'maylce anchored upon suitable pins or like members on the inner faces of

walls

66 and 68. These springs act to retain the platens normally raised into engage.- ment with bottom face 56, or to press fabric, supported upon the platens and between the platens and the presser foot or the feed dog, against face 56 or against the feed dog. ,Each

finger 64 may have an adjustable stop 66 for cooperation with a portion of arm 52 to limit upward movement of the platens, as, for instance, when arm 52 is moved downwardly sufficiently to release the platens from engagement with foot 46. Fingers 82 are spacedfrom each other to provide a passage of sufficient width to permit the extension between them and above the level of sections 66 of arms 66; and 62 of members66 and-62. I

At the end of

arms

66 and 92, and, therefore, above sections 66, the fabric-engaging heads 64 and96 of the bight-forming members are defined. The platens are cut away at 96 to provide a passage through which heads 64 and 96 may be projected when moved to engage fabric carried on the platens and extending beneath slot 48. Slot 46 extends substantially the entire length of the presser foot, except for small bridge sections I66 and I62 at eachend. Thus fabric fed beneath the presser foot is unsupported at the slot except for such support as maybe obtained from the platens and heads 94 and 96.

Arms

96 and 92 are mountedto pivot upon a bearing stud I64 which in turnextends through openings in, and is provided bearings in those openings in,

walls

66 and 68. Arms 66 and .92 extend below stud I64, and, at their respective ends, are pivotally connected to links I 6 6 and I68, which likewise are housed within arm52, extending along within passage II6 provided by

walls

66, 68 and I6, and into chamber II2 at mounting section 64. I I

Arm 52, by mounting section 64, is pivotally mounted on base I6 by means of a large pin 4 which has hearings in end walls H6 and H8 of base I6. A collar I26 secured on pin II4 abuts one end wall H6 and cooperates with a taper pin I22, extended through a wall of mounting section 64 to fix arm 52 with relation to the end of pin II4, to prevent the pin from having any longitudinal movement in its bearings.

Intermediately of pin H4 is secured a collar I24 having an upwardly extending finger I26.

, To the end of finger I26 is engaged a spring I26 extending through the wall of standard lz to be.

received in an individual casing I36 there to be engaged by an anchor pin I32 in the end wall of the casing. Pin I32 is adjustable in order to vary the tension of spring I28, The tension'of spring I28 serves to turn pin II4 so that arm 52 will move upwardly into position to bring the'platens' into engagement with the presser root. Collar i24aalso hasanarm 134 which extendsxforwardly irom the collar ito-la position 1 immediately beneath' a plunger I36 which isccarriedxupon a screwethreaded pin I38. 1 Thepin mayibe secured to .a knurled knob I42 positioned-on, the :topfface of base I0, the. pin extendingthrough an. opening in' the base, and the knob being "retained against-separation from the base andso' that, on rotation, plunger I36 will ,move uporzdown, according to the rotationof the :knob. -Thea tion of .spr-ing I28 is to .drive arm-I34 into engagement with plunger 136, .to limit upward movement ofarm 52, and in accordancewith the setting of'plunger-I36. A safety stop I44 may-also be mounted lassociation wit'h knob I42,- and-may be adjusted through an opening in base-I to'limit the adjustment derived from knob 1-42-50 that members 60 and fizmay not be projected dangerously into the a path of the needle. r

Also supported in bearings in base I0 is shaft I46, the bearings being formed in wall I I6 of the base and in a boss I48 extending downwardly from the top wall of the base. A pair of collars I50 fixed to the shaft retain it against longitudina'l'movement. The-shaft extends beyond "wall I I6 and into chamber I I2, and, rear-wardly of pin II4, through a large opening "I52 provided for that purpose. Shaft I-46 does not move with arm 52.

' On end I54 of shaft I46 extending into chamber H2, a pair of cranks I56 and-I58'are-afiixed, as, for instance, by means of clevises in-addition to set-screws,'for retaining the cranks in fixed relationship to end I54. The cranksare disposed substantially opposed to each other, butnot exactly 180 apart. One crank I56 is connected to link I06, While the other crank I58 is connected to link I08, and thus provide for oscillation of the

respective members

60 and 62 to bring their effective heads 94 and 96into cooperation with fabric pressed against the pressenfoot.

"At the other end of shaft I46, a crank I68 is fixed, as, for instance, by means of a clevis I62. Crank I60 has a bearing for a shouldered pin 164, the bearing being in an opening at theend of the-crank. To the eX-tendi-ngend I68 of-pin -I64 is'fastened the devised endportion I70 of an eccentric strap I12. The eccentric strap extends upwardly through passage H4 in standard I 2, and has its bore I76 carried uponeccentric I 18; Eccentric I'I8is mounted upon a pin I80, the pin extending transversely between the walls of standard I2. Fixed with eccentric I78 is a gear I82, this gear being meshed witha gear I84 carried upon main shaft 24. In theparticular instance sh'own, gears I82 and Iibi are in twoto-one relationship, that is, for every two revolutions of shaft 24, eccentric strap H2 will complete one cycle, so that shaft M6 will complete an oscillation. I

Gears" I82 and I84 are so timed, and cranks 56 and I58 are so disposed with regard to'the center of shaft I40, that one of the heads 94-and=96 will be brought into engagement with fabric carried onthe platens while the other head is moving out of and away from engagement with the fabric, and at the time the needle is passing into the fabric projected by the bight-forming mem 'ber. JThus fabric retained between the platens and" thepresser foot will be biased upwardly only byoneof the bighteforming'members-at any single reciprocation of the needle.

.iiiabriezfed through the machine is: pressed lup- .wardly, as previously "describedby platens-fifl.

Pressing down:againstithetiabridis: .a nshoe 86, .as 'shownin Figs.'i 8.,*'9, .lOzand-Ail. fI h'is :shoe 'i's-an integral part :of a bearing sleeve L188 which is providednawbearing .011 .aaheaded 'ipin' I90. This pin in turnis received in: a :bore 192:.eccentrically formediinaspl-it sleeve= I94. zsleeve l 94 in turn is received inacbore I=96 formed in an upright lug 49.8 which 11 may azbe .'formed l substantially tintegrally with apresserafoot 146. fSleeve I94 has 'afslot ioflz forseng-agement :ofia screwdriver or similar tool to rotate sleeve I94.

. However, .sleeve 1 fldcnormallyzis anchoredi and .compressedbymeans oroa set-screw: 202 inl lug 1 ea, the compressed sleeve servingitorretainpin 190-:againstrotaticn. rI-Iowever, onirelease from thecompressing action of iscrevv' Z-OZ, sleeve-I 94 may be rotated within bore I96, and, because of the eccentricity, thus 1- serve to lift and lower pin I as :well as-to advance and retractthe pin relatively-to slot "48, and-thus serveas one means for adj ustingsthe'positionbf shoe 4-86.

. Shoe I86 includesaplate 284 havi ng an opening206, as shownin" Fig. 14, "Through opening 206: extends a screw-threaded-pin zflfl aflixedin presser fo0t46.- A coiled spring '2 l0; assembled on pin 288, is held between plate "204 and-a knurled nut 2 I2 which=is threaded onpin 208. 'The pressure of shoe IBBagainst-material carried between the platens and. the presser foot is thus'regulated.

The bottom face 2-l4-:ofplate-"204 is formed to provide a surface 2l6 to cooperate with head 94. Since this head and surface 2 -I 6 -will -"act upon that portion of the' fabric'which is of lesser thickness; surface 2 I 6 is higher than the other portions of bottom iace' 2I4. Then'bOttomfa ce 214' includes a surface 2| 8 at a lower level than surface 2 I6,-a-nd' from surface 218- there extends '"downwardly awedge-shaped member 220- for cooperationWith'head-QG. I

Medially of plate 2-84 is a slot 224 -formed in plate 204;'andthrough-which extends a rib 226. This rib is an'integral part of an- L 'sl-iapedmem -bcr -228, theiflatportion 230 being anchoredon the top face of platei-M by means of a-screw- 234. Rib 1 226,- surface 2I8, 1a-n'dmember-220 cooperate withhead- 96-'in-forming a bight in-"the thicker portion ofthe fabrlqwedging it-up into the desired V-formation.

' Bearing stud I04 :isprovidedwith ahead 236, the stud being received: through aligned openings "238 in wall's' fid and- 68-so'that head236'abuts the outer face *of wa-ll'68. At'outer muses handle 246 is a flix'ed to the extending-end 242 of the stud;'as, for-instance, by means of a" clevis Handle 240 has a boss 244 formed thereon; ina' passage in the boss slides a pin 246. A spring 248 encirele's-pin*-246- within thepassage and-acts on thet pinrbyth-ismeans, pin 24'6 -is forced-against a quad-rant zfifl fas-tened to-wall 66 by any suitable means such as screws. The outer periphery of the quadrant-may be formed with-teeth A 252 to cooperate with the toothed end of pin-246. 'Sto-p pins 254'- and *2 56 may be mounted either on wal-l'66 oron' the quadrant to provide limits for'movementof'handleZdfl." V

Between "wally-6 6 and- 68, bearing -stu'd- I04 is formed to provide independent-bearings for arms 98 and .92. Arm90 is provided .abearingsection .258which has;i.a..bore concentric withithe axis of the stud, and, i therefore, :on movement a'ofthe stud 'by;. -means: of-han'dle a240,: noi 'changezztakes place in ithecefiective pivoting of '.arm.=.98. An eccentric bushing 11260, afiixed: .toitstudz I-04,1providesafbearin'g Tfor. arm;:92; Thus; asrhandle: 240 :is actuated "to adjust. the". axial r position of stud 104, the axis of oscillation of arm 92 will be changed. Thus, head196 will be brought up towards and moved away from fabric supported on the platens, that is, since the center of oscillation of member 62 will be changed, it Will be made possible for this member to have less or more effect upon the fabric, to push the fabric into the path of the needle, more or less, according to the adjustment of handle 240.

Heads

94 and 96, as seen in Figs. 12 and 13, in addition to being pushers, that is, elements Which push'the fabric vertically, are also seen to have a forward arcuate overhang 262. This overhang, as can be seen, has a cam surface 264 turned downwardly to cooperate with fabric as it is fed through the machine, that is, the fabric riding into the stitching position is brought up the curving surface 264 into position beneath shoe I86.

Fabric being fed to the machine will be considered as consisting of two

pieces

266 and 268, as shown in Fig. 15, the top-most piece being folded back on itself to form a third layer 210, and also to define a fold edge 212. As shown in Fig. 16, the fabric is positioned on the platens by. depressing arm 52 against the action of spring I28. Then the arm is permitted to rise, whereupon, as shown in Fig. 17, platens 50 will clamp the fabric against face 56, and fold edge 212 will then be positioned immediately in contact with the side face of rib 226. The fabric actually crowds into slot 48, and piece 266 will be positioned in contact with surface 2l6. The superimposed formation of

pieces

266 and 268 and layer 210 will be pressed against surface 218 and member 220.

Now, as the fabric is fed through the machine, first head 94, as shown in Fig. 18, will engage with the fabric and push it against the action of shoe 186 into the line of movement of needle 32. The platens are active to keep the fabric in tension as head 94 rises, and thus, although shoe 186 does not clamp the fabric of

pieces

266 and 268 and layer 210 tightly, they are prevented from rising into the path of the needle. At the moment of peak movement of head 94, needle 32 passes through the bight in piece 266, as shown in Fig. 18, and then looper 4!] cooperates with the needle in the usual manner. The needle is retracted; head 94 is lowered; the needle leaves the fabric; and the fabric is fed forwardly by dog 44. Head 94 continues to move towards the operator, and down away from the fabric while, at the same time, head 96 is rising.

In the meantime, looper 40 has transferred its loop into position to be engaged over the needle on the next movement of the needle into the fabric. At the end of the feed motion, head 96, as shown in Fig. 19, will have moved upinto engagement with the fabric to push

pieces

266 and 268 and layer 211! up into position so that edge 212 .will be engaged by the needle, the various layers then cooperating with rib 226 and member 226. Now head 26 is the operative element, functioning for stitch formation. It, of course, is laterally displaced from head 94 and the disposition,

is such that a zig-zag stitch, such as shown in Figs. 20 and 21, will be produced. In such case, thread is first caught at point 214 at which a complete stitch is produced. Then, when head 64 is effective, the thread is caught at point 216; the same cycle of stitch formation now ensues; the thread keeps alternating back and forth from a line of points 214 to a lineof points 216, and. thereby produces substantially a zig-zag stitch,

and what in effect is a skip stitch, sometimes called a floating stitch. The specific type of stitch, formed with a single thread chain stitch machine, is shown in Figs. 21 and 22.

An additional guide for that portion of edge 212 not yet engaged by the platens and associated elements, and to guide the edge up to those elements, may be provided by a finger 218 having an arm 286 affixed to the bottom face of the presser foot by means of a screw 282 passing through an opening 284 in the presser foot. Ann 286 is retained against rotation by engagement against a shoulder 286 in the bottom face of the presser foot. The arm is laterally adjustable by reason of the extent of opening 284. Many other changes could be effected in the particular apparatus designed, and in the method of operation set forth, and in specific details thereof, without substantially departing from the invention defined in the claims, the specific description being merely of an operative embodiment capable of illustrating certain principles of the invention.

What is claimed as new and useful is:

1. A blind-stitch sewing machine having means for supporting fabric in position for stitching operations, means for forming stitches, a plurality of means for effecting movement of the supported fabric and the stitch-forming means towards each other so that thread is engaged in and passed through the fabric by the stitch-forming means, and means to operate each of the movement-effecting ,means at a different operation of the stitch-forming means to produce relative movement towards each other of the supported fabric and the stitch-forming means by each of the movement-effecting means individually of the other, the relative movement effected by each of the movement-effecting means being of a different extent, and means for varying the difference in extent of the relative movements.

2. Means for stitching together a plurality of superposed fabric layers, wherein one of the fabric layers is of lesser extent than the layer upon which it is supported so as to define a layer end edge within the extent of the surface of the supporting layer, the stitching means including stitch-forming meanameans for supporting the fabric layers to retain the layer end edge in posistitching means either the layer end edge or the supporting layer to the stitch-forming means. it

3. Means for stitching together a plurality of superposed fabric layers, wherein one of the fabric layers is of lesser extent than the layer upon which it is supported so as to define a layer end edge within the extent of the surface of the supporting layeigthe stitching means including stitch-forming means, means for supporting the fabric layers to retain the layer end edge in position upon the supporting layer for the stitch-forming operation, and means for effecting movement towards each other first of the stitch-forming means and the layer end edge and then of the stitch-forming means and the supporting layer.

4. A blind-stitch sewing machine having means for supporting fabric in position for stitching operations, means for feeding the fabric along a line in one general direction, means for forming stitches, and means for forming bights in the supported fabric in cooperation with the stitch-forming means on opposite sides of the line for different operations of the stitch-forming means.

, 5. A blind-stitch sewing machine having means fcrsupporting fabric in position for stitching op 1 1' erations,. means .for feeding. the supported fabric. constantly in the same. direction, and -means; for forming stitches in. the. fabric so. supported;ithe forming means including aneedle oscillating in substantially a single path. for-forming blind.- stitches in the. fabric, and means. for effecting movement of thefabric towards and away-from the path of oscillation. of the needle, the move"- ment-eifecting means comprising meansfor selectively effecting movement of the fabric .into stitch forming positions for formation. of successive stitches substantially out of any continuous straight line of stitching.

6'. A'blind-stitch sewing machine having means for supporting fabric in position for stitchingoperations, and means for stitching. the fabric along a predetermined straight line, the stitching means including a needle oscillating in a path for forming blind-stitches in the fabric, and means .for. effecting-movement of the fabric towards and away from the path of oscillation of the'needle, the movement-effecting meanscomprising means for effecting movement of the fabric into stitchforming position on either side ofthe linebut only on oneside'of the line for any one stitch.

7. Ablind-stitch sewing machine having'means forsupporting; fabric in position for stitching operations, means-for stitching thefabric'along a predetermined mean line, the stitching means includinga needle oscillating transversely of the line, means for effecting movement towards the needle of the fabric at points spaced apart along the line and on both sides of the line for engagementby'the needle in forming astitch; and means for making the-movement-effectingmeans operative for effectingxmovement of the fabric on one side only of the line for any single stitch-forming oscillation ofthe needle.

8. A. blind-stitch.sewingmachine having means for supportingfabric'in position for, stitching operations, means for stitching the'fabric along a predetermined meanline, the stitching m-eans including a needle oscillating transversely of the line; means for effecting: movement towardsv the needl-eiof' the'fabric at points spaced apart along the linerand-on both sides of .theline for engagee ment by theneedle in. formin-ga stitch, means for.

making the movement-effecting'means operative for effectingmovement of: the fabric on one, side only of the line for any single stitch-forming oscillation ofthe needle, and-means for. controlling the depth' of penetrationof. the needle'into the fabric in forming the stitch;

9; A blind-stitch sewingmachine having means forsupporting fabric inpositionfor stitching operations, means for stitching the fabric ,along a predetermined mean line, the stitching means including a' needle' oscillating transversely of the line; means for effecting movement towardsthe needle of the fabric at points spaced apart along theline and onbothsidesof the linefor engagement by'theneedle informing a stitch, means for-makingthe movement-effecting means operative for efiecting movement "of thefabri'c' ononesideonly'of the line'for any singlestitch-forming oscillation of the needle, and means for-controlling the depth of penetration-of theneedle into the' fabric in forming the stitch and for adjustingtherelation betweenthe depths ofpenetration of the needle in forming stitches onthe two sides of'"the line.

10. A blind-stitch sewing machine having means for supporting-fabric in position for stitching operations; an oscillating needle for stitching'fabrio-so supported, apair of-bight=forrningmemberszfor-effecting: displacement of fabric and needles towards each. other-:for stitch-formation; means for: moving theamembersso that .one: of thenrisz'supporting. and moving: the fabric into fabric -presenting. .position when the other is out offabric-supporting:- and. fabric-presenting .position; and: meansforrdetermininga, diiferential between the extent of fabricepresenting movements of the members and for adjusting the members relatively-to. each other to vary thedifferential;

111- A- blind-stitchi. sewing machine having means-for supportin'gifabric. in position for. stitching operations, an; oscillatingneedlefonstitching fabric 50 supported, a:pair .0fl,OSCl'11atOI'y bightforming members: for. presenting. the fabricto the needle, and a'support forthermembers,,the.:men bersand; thetsupport including eccentric means for adjusting; therelationbetween the. oscillations .of the-members for varying. the relative penetration. of: the. needle in fabric presented" to the needle; bythetmembers;

12. A. blindt-stitjch: sewing machine having means fonsupporting. fabric inpositionfor'stitching' operations; an oscillatingineedle for stitching fabric 50' supported, .aipair. of oscillatory bightforming members-far presentingthe: fabric'to the needle,.- and a. support f'orthe members; the members andthesupport including: an eccentric bearing for one oftheimembers, the'bearingbeingradjustable to 'varythe relation between the oscillations 'ofxthe members for varying the relative penetration. of: theneedie in fabric presented to the needle by the members.

13. A blind-stitch. sewing machinev having means for supporting fabricin position for stitch ing" operationsgian oscillatingneedle for stitching fabric s0- supported; 3, pair of: bight-forming members for presenting-the fabric to the: needle. a shaft, and means driven by. the shaft for "moving each of the-members individually ofthe other into fabric-presenting position, the membersmoving. means comprising, a single rock arm driven from the shaft, said. members-movin means imparting movement toreturn the members from fabric-presenting. position; the members being adjustable relatively to each other to vary theireffective fabric-presentingspositions.

14'. A blind-stitch sewing machine having means for supporting fabric in position for stitching operations, an oscillating needle for stitching fabric so supported,a; pair of bight-forming members for presenting the fabric to the needle, a support for the members, a shaft, and means driven by the shaft for rocking the members on the support to bringthem individually into fabric-presenting position, the members-moving means including a single rock arm driven from the shaft, said members-moving means imparting movement to return the members from fabric-presenting position, the members and the support having means for'adjusting the relativev limits of movement of the rockedmembers for varying the effective penetration of the needle into fabric presented to the needl'e'by the members.

15. A blind-stitch sewing machine having means for supporting a plurality of superimposed layers of fabric in'positionto be stitched together, the topmost layer being the shorter and presenting an edge along which a line of stitching is to be formed for" securing the layers together, an oscillating needle for forming a line of stitching in thelayers of fabric so retained, a guide for retaining the edge in position during stitching by the'needl'e, and a pair of oscillatory bight-forming membersfor presenting the fabric to the needie on either side of the guide, the members being adjustable relatively to each other to vary the effective penetration of the needle into fabric presented to the needle by the members.

16. A blind-stitch sewing machine having means for supporting fabric in position for stitching operations, a needle for stitching fabric so supported, a pair of bight-forming members, means for moving the members relatively to each other to a limited extent to bring each member individually, and at one of its limits of movement, into engagement with the fabric for presenting the fabric for needle penetration, and means for differentially adjusting the fabric-engaging limits of movement of the members relatively to each other.

1'7. A blind-stitch sewing machine having means for holding fabric in position for stitching operations, a needle for stitching fabric so held, a support, a pair of bight-forming members pivotally mounted upon the support, means for oscillating the members on the support to a limited extent so that one member is moving, at one of its limits of movement, into engagement with the fabric for presenting the fabric for needle penetration while the other member is moving away from the fabric, and means for differentially adjusting the fabric-engaging limits of movement of the members relatively to each other.

18. A blind-stitch sewing machine having means for holding fabric in position for stitching operations, a needle for movement in a path to engage and form stitching in fabric so held, a support, a pair of bight-forming members pivotally mounted upon the support for movement towards and away from the stitching path of the needle, and means for moving the members relatively to each other on the support to a limited extent so that one member is moving, at one of its limits of movement, into engagement with the fabric for presenting the fabric for needle penetration while the other member is moving away from the fabric, each of the mem of the support to vary differentially the fabricengaging limits of movement of the members relatively to each other.

19. A blind-stitch sewing machine having means for holding fabric in position for stitching operations, a needle for movement in a path to engage and form stitching in fabric so held, a support, a pair of bight-forming members pivotally mounted upon the support for movement towards and away from the stitching path of the needle, and means for moving the members relatively to each other on the support to a limited extent so that one member is moving, at one of its limits of movement, into engagement with the fabric for presenting the fabric for needle penetration while the other member is moving away from the fabric, the moving means including a single rock shaft, and a pair of cranks extending oppositely from the shaft, each crank having operative relation to one of the members.

20. A blind-stitch sewing machine having means for holding fabric in position for stitching operations, a needle for movement in a path to engage and form stitching in fabric so held, a support, a pair of bight-forming members pivotally mounted upon the support for movement towards and away from the stitching path of the needle, means for moving the members relatively to each other on the support to a limited extent so that one member is moving, at one of its limits of movement, into engagement with the fabric for presenting the fabric for needle penetration while the other member is moving away from the fabric, the moving means including a single rocl: shaft, and a pair of cranks extending oppositely from the shaft, each crank having 0perative relation to one of the members, and means for rotating the support to vary differentially the fabric-engaging limits of movement of the members relatively to each other.

21. In a blind stitch machine having means for supporting fabric in position for stitching operations, and means for forming stitches, the

combination with the fabric-supporting means and the stitch-forming means of means for presenting the supported fabric to the stitch-forming means including a plurality of elements positioned in side-by-side relationship, and means for presenting the elements one at a time to the fabric and the stitclnforming means so that each eiement wholly by itself and without assistance from the other of the elements is in fabric-presenting association with the fabric and the stitch forming means.

22. In a blind stitch machine having means for supporting fabric in position for stitching operations, means for forming stitches, the combination with the fabric-supporting means and the stitch-forming means of means for presenting the supported fabric to the stitch-forming means including a plurality of elements, means, for presenting the elements to the fabric and the stitch-forming means so that but one of the elements and without assistance from the other of the elements is in fabric-presenting association with the fabric and the stitch-forming means at any operation stage, and means for adjusting the elements to vary the effective fabric-presenting association of the element with the fabric and the stitch-forming means.

JOSEPH SCHIFIER. HENRY L. BURKI'I'I.

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

UNITED STATES PATENTS Number Name Date 1,828,789 Strobel Oct. 27, 1931 2,108,101 Buono Feb. 15, 1938 2,113,107 Bowman Apr. 5, 1938 2,161,527 Mueller June: 6, 1939 2,189,433 Mueller Feb. 6, 1940 2,244,224 Stevenson June 3, 1941