US1405855A - Stitch-forming mechanism for sewing machines - Google Patents

Description

I. R. IVIOFFATT.

STITCH FORMING MECHANISNI FOR SEWING MACHINES. APPLICATION FILED IULYIB, 1917.

1,405,855. PatentedFeb. 7, 1922.,

6 SHEETS-SHEET I- J. R. MOFFATT.

APPLICATION fILEI) JULYI8. 19|?.

STITCH FORMING MECHANISM FOR SEWING MACHINES.

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1. RfMoFF/W. STITCH FORMING MECHANISNI FOR SEWING MACHINES.

IMPLICATION FILED JULYIB. 19H. Patented 7 s lsmilaTs-smnz s.

J. R. MOFFATT. STITCH FORMING MECHANISM FOR SEWING MACHINES.-

Patented Feb. 7, 1922.

6 SHEETS-SHEET 4- APPLICATION FILED JULYIB. 1917.

` J. ramon/IIT.'

STITCH FORMING MCHANISM FOR SEWING' MACHINES.

rammed Feb. 7, 1922.

`.I\PPLICATION FILED IULYIB, I9I7- 6 SHEETS-SHEET 5- J. R. MOFFATT.

STITCH FORMING MECHANISM FOR SEWING MACHINES. APPLICATION rILEDIIILYIs.I9I1.

` 1,405,855, rammed Feb.7,1922.

6 vSHEETS-SHEET 6.

UNITED STATES PATENT oFFlCE- JAMES R. MOFFAT'I, CHICAGO, ILLINOIS, ASSIGNOR T0 UNION krSPIECIAI'.' MACHINE COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION F ILLDTOIS. n

STITCH-nomme MECHANISM FoasEwiNG MACHINES.

- v Application led J`u1y'18,

To all whom 'it may concern.'

Beit known that I, JAMES It. MoiFA'r'r, a citizen of vthe United States, Vresiding at Chicago, in the county of Cook, State of. Illinois, have invented certain new and useful Improvements in Stitch-Forming" Mech,- f

anism 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.

Theinventionrelates to new anduseful improvements in stitchlforming mechanisms for sewing machines, and more particularly to the mechanism for laying a crossthread between and connecting needle threads on the upper surface of the fabric.

An object of the invention 1 character having a thread-hook for engaging the cross-thread and forming a loop therein, and with a stationaryV finger against which the cross-thread is drawn bythe hool These and other objects w1 fully disclosed. In the drawings',- Figure l is a front view of a sewing machine embodying my improvements and hav-v ing a part thereof broken away to show the loop'er; A

Figure 2 is an enlarged front view of the end of the sewing machine with the edging guide removed;

Figure Sis an end view of the machine, showing the parts at the end of the overhanging arm, the overhangingarm being omitted;

Figure isV a view partly in top plan and'partly in section, the section being taken directly beneath the lower bearing ofthe cverhanging arm; l

Figure 5 is a perspective view showing the' needles, the thread-hook, the thread nger and the thread-'guides forthe cros^- thread, the hook'being at the forward end of its stroke; Figure 6 is a plan View showing the Athread s to provide ,y a stitch-forming mechanism ofthe above llA in part y'be obvious and willin part be hereinafter morey 1917; Serial No.. 1"s1,2os.

specification of Lettersrat'enf. Patented' Feb. 7,1922,

forward -end of its stroke;,` and also show ing the fabric, the edgingand the interf.

'v 60 Figure 7 is a'view similar to. Figure 5,

chained cross-threadand needle-threads;

but showing a slightlyl modified form". of stationary thread-finger; v

Figure 8 is av plan Vview showing the thread-hook, thethrea'd-finger and the fixed thread-guides for the cross-thread;

Figure 49sis a AView similar,V to Figurej,vv

but showingthe hook at'the rear end 'of its stroke and as about to engage'the cross- Figure 10 is a 'diagrammatic view, showing the relation of the threads to the fabricv 'n and the edging.

The invention is embodied 'in' astitching y mechanism consisting of a plurality' of needles whichv are arranged abreast andwith which a single looper co-operates beneath` the Work support. (lo-operating vwith these needles above the work support is a crossthread-laying hook adapted to engage a cross-thread and form a loop therein for one of the needles to enter.,

Associated with the Vcross-thread-l'aying Vhook is a finger against which the cross# thread is drawn, and this finger is so shaped that the pull of the hook on the cross-thread will cause the cross-thread 'to slide( rear Wardly on the finger and be positioned between the needles. Also associated with the finger and the cross-thread-laying hook is a needle bar, through Vwhich the cross-thread extends, andthis thread-guide on its .downward movement serves to bring the lcrossthread to its forward position on the' threadfingerwhere it willbe engaged by the hook thread-guide movable up and down with the as it next movesy forward to form a loop.

Referring more'in detail to the drawings, my improved stitch-forming mechanismis shown as applied to a sewing machine having a work support 1, an overhanging arm 2 in which reciprocates a needle bar 3, carrying a pair of needles 4 and 5; (3o-operating with the needles 4f and 5 beneath the work support' is a threaded looper 6. Said looper is pivoted at 7 and is oscillated by alink 8. This link 8 is pivoted at its other end to the needle lever extension 9 carried bythe needle lever l0.

c The needle lever 10 is connected by a link l1 to the needle bar@ The needle lever is'oscillated by the eccen Y triclstrap 12 which, eo-operateswith the eccentric on the main shaft, and the main shaft is rotated by the usual belt wheel'13.

The material is held on the worksupport by a presser foot 14 carried by a presser bar 154 mounted in the overhanglng arm. The

. needle 4 is provided with a needle-thread 4,

while the needle is provided with-a needlethread 5a. These needle-threads pass through a suitable/'guide 16 "at thejupper end of the needle bary and valso through guides17 and 18 on the needle lever. Said threads between the guidesl and 18 pass through a threading mechanism described, are of the well cross-thread is led Vfrom atension 21 through spaced guides`22, 22; and thence through a fixed thread-guide 23 formed in an arm 24 guide 19. Y These thread-guides and the stitchknown construction and further .detail de `scription thereof is not fthought necessary.

The needles pass down through the fabric vand the looper enters,` both threaddoops formed by the needles, and the looper-thread is thereby concatenated'` with both needlethread loops. j p The needle-threads are joined on the upper face of the fabric by a cross-thread 20. This secured to a bracket 25 attached to the overhanging arm of the machine.v An arm 22` carried by the needle bar .engages the crossthread between the guides 22, 22 for pulling,

offthe cross-thread.

Mounted on the needle bar d3 is an arm 26 havinga thread-eye 27.- The cross-thread passes through thisvthread-eye; Thecross'- thread is formed into loops by a thread-hook 'y means of screws 33, 33.L The lever. 32 extends to lthe rear of the overhang-ing' arm, 'and is 28.v v V'1`histhread-hook is formed with'a notched end 29 and-with a shank 30, which' extends vertically vthrough a sleevel carried by a lever orf thread-hook carrier 32. The shankO is adjustably held in the sleeve: by

pivotally supported by the bracket 25.l Said brackethas'spaced ears carrying a vertical i shaft 34, to which the lever 32 is secured. Y The lever32 is'provided with a ball stud 35 and a link 86bis pivotally attached to this vball stud. j The link 36 at itsother end is piv- :otally connected at 39 to a bracket 40 carried at the lower end of the needle lever extension 9. As the needle lever extension oscillates, the lever 32 will be oseillated, and thiswill move' the vthread-hook back and forth across lthe line of feed, or across a vertical plane passing centrally between theneedles.

.the needles.

"which the. screws extend are elongated ver- Y itically, so thearm 42 maybe raised and,

lowered slightly.

The thread-finger 41, asV sho-wn in the drawings, is provided with a slot 43. The wall 44 of this slot is, however, the only active .surface against which the threadvis moved. As clearly shownY in the drawings,

thissurface is shownas yconsisting of a concave. curved surf-ace, which leads into a convex curved'surface, the convex curved surface forming theV curved shoulder 45.-

V'Vhen the needles are clear down, as indicatedin Figure 9 0f the drawings, the

thread-hook is at the extreme rear end of its stroke. The threadeguide 27l for the cross-thread is at the lower end of its stroke' 'and is so disposed relative to the linger 41 as to draw thecross-thread vforward on the finger to a point adjacent the forward .Vendi Whenthe cross-thread is thus of the slot. j y positioned, as the hook moves forward, Yit

. engages the cross-threadQ- That is to say,

thenotch in the thread-hook moves-underneath the finger at thel forward end of the curved slot. After the' hook has engaged the cross-thread, it forms the crossthread yinto a looprin the well known way, which loop wil-l be entered bythe needle farthest from the thread-finger. It is also desirable that the cross-thread should pass4 between As the hook; moves forward,

it pulls the cross-threadaigainst this threadfinger andthe guide .27 moving upwardly away fromthe finger, permits the pull on along the finger.

the thread to draw the thread rearwardlyV Inasmueh as `the finger is concaveat the `forward end thereof, the thread will be given up quickly andV easily to the hook. Just as the-.thread is reaching the rear end of its movement along the finger, it slides along the convex curved shoulder 45 and this takes any slack out` of the thread, so it will be. held taut by the hook needles are past the thread.

When the cross-thread reaches this position, as clearly shown in Figure 5, the

needles will Ypass down, one on each side of the thread between the notch in the hook and the thread-finger, and the left hand needle or needle 4 will enter the threadloop formed in the cross-thread. vWhen the thread-hook returns, the loop is dropped, and the movable thread-eye on the Vneedle until the bar will draw thecross-thread again to the forward end of the slot. y Y

In Figure 7 of thedrawings I have shown a slightly modified form of thread-finger 4l. In this form of thread-finger therev is no slot, but the surface 44 isshaped substantially as above described andthe crossthread slides along this surface. The

thread-hook may be adjusted vertically and also the thread-finger may be .adjusted vertically, to bring 4these parts intoproper 'co-operative position relative tothe needles.

thence through a guiding device 47; and

thence Jaround av guiding roller 48, carried by the presser foot. The edging is directed so as tov slightly'overlap the edges' of the fabric. The needles 4 and 5 both penetrate'- certainty. 1

the fabric and the needle 5 passes through the edging. nected below yby the looper thread, and are connected .abovey 'by the cross-thread, and the cross-thread thus firmly secures and covers'the edge portion of the edging where it is joined to the fabric. i

F rom the above description', Lit will be apparent that I have provided a crossthread-laying mechanism in which the crossthread is positively handled by a minimum number of movable parts, and, therefore,

there is little or no wear on the cross-thread and it will be laid with certainty relative to the needles.

It is obvious that minor changes in the details of the construction may be made, without departing from the spirit of the invention as set forth in the appended claims.

Having thus described my invention, what I claim as new and desire to secure by Let-- ters Patent, is:

l. The combination with Va plurality of needles and complemental stitch-forming mechanism, of a thread hook for forming a loop in a cross thread for certain of said needles to enter, means against which the cross thread is drawn by the hook, said means being shaped so that, as the cross thread is forced against the same by the hook, said cross thread will move rearwardly while in engagement with said means and position p one strand of the loop between the needles.

2. The combination with a plurality of needles and complemental stitch-forming mechanism, of a thread hook for forming a loop in a cross thread for certain of said needles to enter, a thread finger against which the cross thread is drawn by the hook, said linger being shaped so that, as the cross thread is forced against said thread finger by the hook, said cross thread will move lrear'- wardly while in engagement with said thread finger and position one strand of the cross thread between the needles.

3. In cross threadflaying mechanism, thev combination with a plurality of needles and complemental stitch forming mechanism, of

,a feeding mechanism, a reciprocatory thread hook for forming loops in a cross thread for one of said needles to enter, means for operating said hook, a guide for the cross thread The needle-threads are lcondisposed in a' position -above the vpath vof movement of :thefree end of the hook and voperatingto position the thread infront of the; hook so that said-hook ywill engage the thread withv certainty, and means; against which one strand'of the loop is carried byy the forward movement of said hook whereby said vstrandLwill be positioned between the f'-needles, -and'feeding mechanism operating .to

rearwardlymove the other strand'of the loop 1 whereby-the needle farthest removed from the lloop with said thread guide will enter 4;' The 1 combination with ay plurality of needles f and complementalk stitch-forming mechanism, of-afthread-hook for forming a loop'in a cross-thread for one of saidneedles toenter, Vand" a fixed. thread-finger against which the cross-thread isk drawn, said finger having a curved surface disposed relative to the movement of the hook, so that the pull ofthe hook will cause the thread to move backward on thefinger and be properly positioned relative tothe needles. p

5. The combination with a plurality of needles and complemental stitch-forming mechanism, of a thread-hook for forminr a loop in a cross-thread for one of the needles to enter,a vertically movable guide for the cross-thread, a stationary finger against which the cross-thread is drawn by the hook, said finger being shapedvso as to move the thread rearwardly to properly position the same relative to the needles as the hook pulls out the thread, and said thread-guide being so positioned as to return the cross-threadto the forward end of the linger for engagement by the hook on its next forward movement.

6. The combination with a plurality of needles and complemental stitch-forming mechanism, of a thread-hook for forming a loop in a cross-thread for one of said needles to enter, a fixed thread-finger having a curved face against which the cross-thread is drawn by the hook, said curved face operating to move the thread rearwardly as the hook.` pulls on the thread, the forward portion ofthe curved face against which theV curved face against which the cross-thread is drawn by the hook, said curved face operating to` move the thread rearwardly as the hook pulls on the thread, the forward portion of the curved face against which the thread is pulled by the hook being concave and the rearward portion against which the thread isYdrawn-being convex, said convex surfacek co-operating with the hook to pull lthe thread taut, and a vertically movable thread-guide forthe cross-thread, said vertically movable thread-guide vbeing positionedso as to move the thread forwardV on said finger when released by the hook into position to be engaged by the hook on its next forward movement. 5

' 8. `The combination with a needle bar, a plurality of needles and complemental; stitchforming mechanism, of a thread-hook for forming a loop in a cross-thread for one of V the needles to enter, a stationary fin er against which tliecrossthread isdrawnA y vthe hook, said finger being shaped so as to move the crossthread rearwardly as the threadv is pulled thereagainst--by the hook aV thread-guide Carried by the needle-bar or said cross-thread, said thread-guide being-.so l positioned that inits vertical movements said-tliread-guide ,Will4 movefth'e thread forl iva-rd on tliejlinger when released by the hook .and yposition ythe same for engagement by the;`

hook on its next forward movement.Y Y'

9. The combination .of a plurality Y of needles, a eross-tliread-laying hook, a fixed thread-linger. (3o-operating With said crossthread-laying f hook, la .i lever for ysupporting levier, Wherebytlie samemay be adjusted vversaid hook, said hook being,attachedV to said tically, and means for supporting said fixed f tliread-ingerrwhereby it be vertically" adj-usted;

In testimony whereof', I aiiix my signature

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