US1366476A - Stitch-forming mechanism for sewing-machines - Google Patents

Description

J. R. MOFFT T.

STITCH FORMING MECHANISM'FOR SEWING MACHINES. APPucArxoN HLED MAR. 29, 191s.

1 ,366,476. Patented Jan. 25, 1921.

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A l Clftotnn J. R. MOFFATT. STlTCH FORMING MECHANISM FOR SEWING MACHINES.

APPLICATION HLED 11.29. 191s. 1,366,476. Patented Jan. 25, 1921.

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J. 8.MOFFAIT. STITCH FoIIMING MECHANISM FoII SEWING MACHINES. APPLICATION FILED MAR. 29. |918.

1,366,476. Patented Jan. 25,1921.

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STITCH FORMINGME'CHANISM FOR SEWING MACHINES. APPLICATION' man ML2-9. lala.

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J. R. MOFFATT. STITCH FoRMlNG MECH/msm Foa sfwmc MACHINES.

APPLICATIl-)N FILED IAR-29. |918. Patenm Jan. 25. 1921i 5 ,SHEET S-SHEEY 5.

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UNITED srArg vlgivlllilhl'fvOFFICE.

JAMES R. MOFFATT, 0F CHICAGO, ILLINOIS, ASSIGNOR TO UNION SPECIAL MACHIN COMPANY, or'cnrcseo, rumor S, A CORPORATION 0F ILLINOIS.

STITCH-FORMING ISM FOR SEWIN G-MACHIN ES.

Specification of Letterslatent.

Patented Jan. 25, 41921.

Application led March 29, 1918. Serial No. 225,488.

T o all fr0/lam t may concern.'

Be it known that I, JAMES R. Mor-Farr, a citizen of the United States, residingat Chicago, in the county of Cook, State of Illinois, have invented certain new and useful Improvements in Stitch-Forming Mechanism for Sewing-Machines, of which the following is a description, reference being had to the accompanying drawing' and to the figures of reference marked thereon.

The invention relates to new and useful improvements in stitch forming mechanisms for sewing machines and more particularly to a stitch forming mechanism having` devices adapted to join the meeting edges of fabric sections and for covering the meeting edges thereof.

An object of the invention is to provide a stitch forming mechanism of the above character wherein the fabric sections being stitched are supported by a cylindrical work support and wherein said fabric sections are fed onto the work support underneath the overhanging arm carrying the stitching elements located above the work support, and wherein said stitching elements are arranged so as to provide ample clearance space underneath the arm for the handling of the fabric sections.

A further object of the invention is to provide a machine of the above character wherein the edges of the fabric sections to be' joined are trimmedprior to the stitching of theV same by horizontally,-disposed trimming' devices4 and wherein the lines of stitching are joined by across thread which covers the upper surface of the meeting edges of the fabric sections. Y

Astill further object of the invention is to provide a stitching. mechanism of the above character wherein the movable trimming blade and the thread hook for laying the cross thread, are both operated from a single eccentric.

These and other objects will in part be obvious and will in part be hereinafter more fully disclosed.

In the drawings which show by way of illustration one embodiment of the invention Figure l is a side view of a machine embodying my invention;

Fig. 2is a front elevation of the parts located at the front end of the machine. showing the work supporting cylinder in end view;

Fig. 3 is an enlarged view of the front end of the machine as viewed from the same side as in Fig. i with the work support broken away to show the looper and the trimming lever broken away to show the cross thread laying' mechanism;

'F ig. 4 is an enlarged view of the opposlte side of the machine, with the work support broken away to show the looper and a part of the feeding mechanism, the presser foot also being in section;

Fig. 5 is a sectional view on the line 5-5 of Fig. si, the tension for the cross thread being omitted;

Fig. G is a sectional view on the line 6--6 of Fig. l; and

Fig. 7 is a view showing the relation of the fabric sections to the stitching and covering threads. I

The invention is especially adapted for a sewing machine having a standard carrying a cylindrical work support and an overhanging arm which isrparallel with and overhangs the work support. The fabric sections to be joined are fed onto the work support and in a direction parallel with the longitudinal axis thereof. The edges to be joined are turned out of the plane of the fabric sections and are trimmed by horizontally disposed trimming members, after which they are preferably slightly overlapped and they are then joined by a three needle stitching mechanism, the center needle only, passing through the overlapped fabric sections. Coperating with the needles beneath the work support, is a single looper and cooperating with the needles above the work support, is a thread hook and thread finger, which lays a cross thread in loops for the needles to enter. Thus the cross thread joins the lines of stitching and covers the edges of the joined fabric sections. The stitch forming elements are all operated from a cross shaft at right angles to the work support. The movable blade of the trimming mechanism and the thread hook are both operated from a single eccentric on the cross shaft and the connections between this eccentric and the hook and trimming blade are so disposed as to givel ample Yclearance room for the handling of the fabric sections underneath the work supporting arm. Y

Referring more in detail -to the drawings, I have shown my invention as applied to a machine having a supporting basel, carrying a standard 2, on which is mounted an overhaiiging arm' 3. Projecting from the standard 2 is a cylindrical work supporting arm or bed t. This worksupporting arm is located directly underneath the overhanging arin and is parallel therewitl'i.V Mounted to reciprocate in the outer end of the overhanging arm 3 is a needle bar 5 carrying three needles 6, 7 and 3.V This needle bar is reciprocated by a needle lever 9 which connected to a link 10, which in turn is con-- nected to the needle bar. The needle lever 9 is oscillated b y suitable means from 'the main shaft indicated in dotted lines at 11 overhan-Uino arm.

jfroin (the extreme in Fig. 1 of the drawings. This main shaft lies in a pla-ne at right angles to the longitudinal axis of the work support.

Coperating with the three needles beneath the work support, isV a threaded looper 12. This loopei' is carried by a looper supporting shaft 13, which is also operated by suitable connections with the main shaft 1.1. The fabric sections are fed onto the work supporting arm and ina direction parallel with its longitudinal axis by a feeding mechanism which includes feed dogs 11i.

VThese feed dogs have their teeth arranged so as to feed the material onto the work supporting arm and said feed dogs are operated by suitable connections with t-he main shaft 11. Machines of this typer are well known in the art and it isnot'thc'ught that furthe-r detail description thereof is necessary.

The material is hel-d on the work support by a presser foot 15. This presser foot is carried by a presser bar 16 mounted in the This presser bar 16 is connected by a pin 1Ga to a collar 16" on the presser guide` bar 16C. The presser bar is forced downwardly by a flatl spring 17, and which bears against a pin 19 fixed to the guide bar 16C.V The pi'esserbar is raised by ka lever 18 which engages the pin 19 on the presser guide bar. The presser foot is formed with a. guiding slot 20 `which leads front end thereof in the line of feed and terminates just Vin front of the needle opening 21, whichreceives the three needles G, 7 and 3. Mounted in a re- Vcesspii'i Vthe presser foot is a 'fixed trimming blade 22. Coperating with this fixed trimming bladel is a movable trimming blade 23.

Y Said movable trimming blade is carried by a lever 24. Y At the end of the lever 24 is a vertically adjustable block 21a to which the blade 23 'is clamped. The inner end'of the Vfixed blade 22 preferably terminates at the side wall of the guiding slot'20, while Vthe movable blade 23 moves across the Guiding z: C Y

shown diagranmiatieally in Fig. 7 of the drawings. In this igurerof the drawings, I have indicated the fabric sections at F and F', the needle threads for the needles 6, T

and 8 respectively, at 6, 7 and 8, the looper thread at Z and the cross tl-iread at c. Tt will' be noted that the fabric sections are so Vdisposed that the central needle 7 passes through the overlapped edges, while the needle G passes at one side of the overlapped edges and the needle 8 on the other side thereof. The cross thread c and loopei' thread Z cover the edges ofthe oined fabric sections.

The lever 2ak is mounted to swing about a guide bar 26,.V which in turn is mountedrin the overhanging. arm and is connected to an arm 27 projecting from the presser foot.

Said lever 24 has a forked bearing and the arm 27 extends between the Vmembers of the fork. This. connection holdsk the lever from sidewise movement on. the bar 2G. A arm 27'is Vconnected'to the bar 26 by a .set screw 2S. The lever 24 is not adinet-able sidewise and the movable trimming blade is adjusted vertically by shifting the block 2111. Preferably formed integral with the arm of the lever carrying the trimmer blade 23, is an aim 29 which serves to oscillate the lever. This arm 29 carries a ball stud 30v to which a link 31 isattached. Ti elink 31 in turn is connected to a. lever 32, which is fulcrumbed at 33 on the overhanging. arm. Mounted in the forward end of the overh-a-nging arm is a cross shaft-3t This cross shaft 34 cari'ies an upwardly extending arm 35. Y Pivot'ed to this Vupwardly,extendingVV arm e5 a ecris@ iink 37. saiaiinie in @um is pivoted at 38 tothe lever 32. The cross shaft 34: is operated by a link 39 which is pivoted at etO'to the arm 35 on Vthe cross shaft 34. The other end of the link 39 is pivoted to a leveir41, which is fulcru-med at vl2 on a lug 43 carried bythe standard.

The lower end of the lever l1 is pivote'dat la te an eccentric strap 45, which cooperates Vwith an eccentric 461.011 the mainshaftv11.

As the main shaft rotates, the eccentric #16 will oscillate Ythe lever Hand through. the vlink 39 oscillatesvthe cross shaft 3V and through the link 31V oscillate the lever 2st4 carrying the. movable. trimmer blade 23.

The cross thread indicated at c in the Y dra-wings is laid inloop form `.for the needles by a thread hook a7 and a cooperating thread finger 4:8. The hook 47 is carried by a lever 49 which is mounted to turn about the presser bar i6 as an axis. Said hook l? has an upwardly extending shank 50 which is mounted in the outer end of one arm of the lever 49. The other arm of the lever 49 is pivoted at l to a link 52.A Thelink 52 is in turn pivoted to a downwardly extending arm 58 carried by the cross shaft 34, As the cross shaft oscillates through the movements of the link 39,- this arm 53 will be oscillated and this will in turn oscillate the lever L19 carrying the thread hook '-17. rllhe thread linger 48 isprovided with a shank 5a which is mounted in an arm carried by a collar 56. The collar 56 is clamped to a split sleeve 57 by a clamping screw 58. The lever 49 swings freely on this collar. The specific mounting of the cross thread laying hook and the finger, forms no part of the present invention, but is shown, described and claimed in my copending application, Serial Number 220,046, filed March 2, 1918. The cross thread c passes through a thread guide 59 carried by the needle clamp 60 at the lower end of the need-le bar 5. This thread guide 59 moves up and down with the needle bar. The cross thread c also passes through a tension 6l mounted on the ovei'- hanging arm. rlhe thread finger a8 is shaped and positioned relative to the guide 59 so that when the guide is at the lower end of its stroke and the needles are clear down, the cross thread will be moved forward on the finger and positioned so that the thread hook as'it moves forward, will engage said cross thread. As the hook continues its forward movement, thethread guide 59 moves upwardly and the pull of the hook on the thread will cause the thread to slide back on the linfrer and be )ro erl Y )ositioned so that the needles 6 and 7 will straddle the thread thus the `cross thread is stitched to the fabric sections. This particular shaping of the thread linger and the relation of the same to the movable cross thread hook and the Vmovable thread guide on the needle bai', are shown, described and claimed in my copending application, Serial Number 181,208, sied July is, i917;

A combined cover anddefiecting plate 62 is pivoted at 63 to an arm 64 extending outwardly from thepi'esser foot and this cover plate 62 covers the thread hook and extends across the movable trimming blade just in -rear of the pointof trimming, so that the trimmed off strip is deflected away from the stitching mechanism.

From the above it will be noted that the movable trimming blade and 'the thread hook are both operated from a single eccentricand through a series of levers'and connecting links, the proper timing and stroke of these devices are` obtained.

It is obvious that minor changes in the details of construction and the arrangement of parts, may be made without depart-ing from the spirit of the invention as set forth in the appended claims.

Having thus fully described my invention, what l claim is new and desire to secure by lLetters Patent is rl. A sewing machine including in combination, a standard, a cross shaft, a work sup-porting arm projecting from the standard, an overhanging aiin carried by the standard, stitch forming` mechanism including a cross thread laying device, horizontally disposed trimming blades located in front of the Astitch forming mechanism, one of said blades being movable, an eccentric on the cross shaft, a rock shaft carried by the overhanging arm, means for oscillating thc rock shaft from said eccentric, an arm on said rock shaft and devices actuated thereby for oscillating said thread laying device, and a second arm on said rock shaft and devices actuated thereby for oscillating the movable triiinning blade.

2. A sewing machine includingl in combination a standard, a cross sha-ft, a work supporting arm projecting from the standard, an overhanging arm carried by the standard, stitch forming mechanism including a cross thread laying device. horizontally disposed trimming blades located in front of the stitch forming mechanism, one of said blades being movable, an eccentric on the cross shaft, a rock shaft carried by the overhanging arm, means for oscillating the rock shaft from said eccentric, an arm at one end of said rock shaft and devices actuated thereby for oscillating said thread laying device, an arm at the other end of said rock shaft and devices actuated thereby for oscillating the movable trimming blade.

3. A sewing machine including in combination a standard, a cross shaft, a work supporting arm projecting from the standard, an overhanging arm carried by the standard, stitch forming mechanism including a cross thread laying device, horizontally disposed trimming blades located in front of the stitch forming mechanism, one of said blades being movable, an eccentric on the cross shaft, a rock shaft carried by the overhanging arm at the forward end thereof, said rock shaft having an upwardly extending arm, a lever carried by the standard at the rear end of the overhanging arm, means Yconnected to the lower end of said lever for oscillating the same from said eccentric, a link for connecting the upper end of said lever with the arm projecting upwardly from the rock shaft and devices actuated by said rock shaft for oscillating the thread laying device and for oscillating thc moi/'able trimming blade.

4. A sewing machine including in combination a standard, a cross shaft, a work supportingl arm projecting from the standard, anl overhanging arm carried by the standard, stitch forming mechanism includ- Ving a cross thread laying` device, horizontally disposed trimming blades located in front of the stitch forming mechanism, one of said blades being movable, an eccentric on the cross shaft, a rock shaft carriedby the overha-nging arm at the florward end thereof, said rock shaft having an upwardly extending arm, a lever carried by the standard at'the rear ends of the overhangino' arm, means connected to the lower' end or said lever for oscillating t-he same from said eccentric, a link for connect-ino' the upper end of said lever with the armrpro- Yiecting upwardly 'from the rock shaft, an

movable trimming blade for oscillating the same. Y Y

5. A sewing machine including in combination a' standard, a cylindrical work sup porting arm ,projecting therefrom, an overhanging arm, means for iieeding, the material longitudinally of the arm, a presser foot, a presser bar supporting the same, a ixed horizontal trimming blade carried by the presser foot, a movable horizontal trimming blade coperating` with the fixed blade, a lever carrying -said movable trimming blade, a bar mount-edler vertical movement in the head and connected to the presser bar 'or supporting said lever, a lever mounted on the overhanging arm and having a link connection with the lever carrying'the trimming blade, a cross shaft in the standard and means actuated by the cross shaft or oscillating the last named lever.

lnV testimony whereof, I aix my signa.- ture, in the presence of two Witnesses.

JAMES R. MOFFATT.

lVitnesses i i S. lGrnonen Tarn, RALPH S. KnLso.

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