US1928587A

US1928587A - Trimming mechanism for sewing machines

Info

Publication number: US1928587A
Application number: US554028A
Authority: US
Inventors: Frederic M Card
Original assignee: Singer Co
Current assignee: Singer Co
Priority date: 1930-05-28
Filing date: 1931-07-30
Publication date: 1933-09-26
Anticipated expiration: 1950-09-26

Description

Sept. 26, 1933 F M CARD l,928,587

' TRIMMING MECHANISM FOR SEWING-MACHINES Original Filed May- 28, 1930 3 Sheets-Sheet l INVENTUR. 51mm; 7%, @WL BY sept. 26, 1933. F. M. cARD 1,928,587s

TRIMMING MECHANISM FOR SEWING MACHINES Original Filed May 28, 1930 3 Sheets-Sheet 2 INV EN TOR.

BY l

ATTORNEY Sept. 26, 1933. F. M. CARD 1,928,587'

TRIMMING' MECHANISM FOR SEWING MACHINES Original Filed May 28, 1930 3 Sheets-Sheet 3 IN V EN TOR. fri/m m, CL4,

BY ATTORNEY Patented Sept.` 2926, 1933 r- No ivrnoimmsivrv Fon SEWING Y -MACHENES v 1 Y Frederic M. Card`, Bridgeport, Conn., assignor to The Singer Manufacturing Company, Eliza- "beth, N. J., a corporation of New Hersey Original application"y May 28, 1930, Serial No.

456,380. Divided andy this application July 30,

1931,. serialNo. 554,028

6 anims. (Crim-$122) This inventionlrelates to improvements in trimming mechanisms for sewing machines and more particularly in trimming mechanisms of the type adapted to trim the marginal portions of mavterials upturned in a presser-foot slot in advance of the pointof seam formation.

The primary object of ythe present invention is to provide fortrimmingthe upturned fabricmargins at a substantially constant distance above the sewing machine work-support in order to insurel a more uniform relationship of the trimmed margins in the stitched seam, whether said margins are abutting or slightly overlappingy in said seam. This object is accomplished by. constructing the trimming mechanism so as to be unresponsiveto movements of the sewing/machine presser-foot due to slight variations in the thicknesses of the materials, but so as to be capable of yielding to bulky portions rof theV work, such as cross-seams, and also so designed as to be shifted when the presser-foot is raised fo f insertion and removal ofV work. c c

The foregoing and other objectsand advantages in View, together with'means whereby the same may be carried into effect, will best be understood from the following description of a preferred embodiment of the invention illustrated,

in the accompanying drawings, in which:

Fig. 1 is a longitudinal section, partlyfin front elevation, of a sewing `machine containing the present improvement. Fig. 2` is a part front end elevation and part section, of the sewing machine with the upper portion of the bracketarm omitted. Fig. 3 is a rsectional view substantially on the line 3-3 of Fig. 2. Fig. 4 isa view in side elevation, partlyin section, ofthe presser-- foot, including asectional view of the throatplate and feed-dogs. Fig. 5 is a rear side elevation, partly in section,of the presser-foot and i trimming mechanism. Fig. 6 is a top plan view of the presser-foot work-engaging plates, omitting the guard blocksandthe'auxiliary foot. Fig. 7 isa sectional View of the machine bracketarm, substantially on the-line 7-7 of Fig. 1. Fig. 8 represents perspective'views, partly in section, of the presser-foot and thesupporting bracket thereof, one of the foot-plates being shown in dotted lines.

This vapplication is a divisionof my prior paty ent application Serial No- 456,380, led May 28, 1930, to which prior application reference may be had for a more complete disclosure of Athe sewingfmachine in which the present improvements have been embodied.y y

Referring to the drawingsthe sewing lmachine is shown kas having a frame comprising a bedplate 1 from one end of whichrises a tubular, supporting, base 2 for thestandard 3 of a tubular `bracket-arm 4, ,which overhangs thebed-plate 1 and terminates in a head 5,. Rising from the bed-plate 1, below the bracket-arm head 5,` is aV tubular work-supporting post. "6 having a hinged closure-plate 7. Suitably secured upon `the upper end of the post 6 is a throat-plate 8 provided with a needle-slot 9 and. suitable feed-slots for feed-dogs 10 and `11 whichfmay be operated rin any appropriate manner to advance the work upon the throat-plate. The throat-plate 8 preferably has a rigid` fabric-margin l'supporting member 12 in front vof the needle-slot 9, said member having a crest 13. f l f Y J ournaled for'rotation in suitable ,bearings providedin the bracket-'arm 4 isv a vmain actuating shaft 14, carrying at its outer end a driving 'pulleyu 15 and at its opposite end a crank-disk 16. This crank-disk. serves to actuate in the usual manner i a linkl'? operatively connected with a vertically disposed needle-bar 18 journaled Ifor endwise reci'procation4 in alined .bearing apertures prop connected with the frame 19 hasat its opposite end a split strap 22 embracing an eccentric *231;

The eccentric 23 is adjustably secured upon var shaft 24r disposed below and crosswise of the,

main-shaft 14, which latter has gear connections with the transverse shaft 240i a character such that said shaft 24 rotates at one-half the speed of rotation ofV the main-shaft. The needle-bar 18.A

effect the production of zigzag stitches.

Cooperating with the needle 25, below the throat-plate, is a loop-taker 26 which in the prescarries at its lower end a needle 25, which through Y ent machine is of the rotary-hook type and car-` l ries a mass of underthread around which the `needle-thread loops are cast in the formation of lock-stitches. The actuating mechanism for the `loop-taker 26 may be of any suitable character,

that embodied in the present machine being substantially the same as disclosed in myhprior Patent No.,1,7z9,994, ceti, 1929..

Opposed to the feed-

dogs

10, 11 is a presserfoot carried by a main presser-bar 27 guided for vertically directed endwise movements in suitable bearings provided inthe bracket-arm head 5. rlhis main presser-bar is yieldingly depressed by the usual spring (not shown) and may be raised and lowered by any manually operated means commonly employed for this purpose. Upon the lower end of the presser-bar 27 is secured by a screw 28 a presser-foot supporting bracket 29, having in its front face a rectangular recess 30 with vertically disposed side walls. Snugly fitted in the recess 30 and secured therein by a screw 31 is the vertically disposed, flattened shank 32 of the presser-foot, this construction providing not only for ready removal of the presser-foot from the machine but also for accurately attaching it to the presser-bar. Projecting horizontally forward from the shank 32 are vertically spaced guide-members 33 provided with vertically alined apertures in which are slidingly disposed the vertically directed auxiliary presser-

bars

34 and 35. The lower ends of these auxiliary bars carry horizontally disposed

shoes

36 and 37 entering the channeled

heels

38 and 39 of presser-

foot plates

40 and 41, which respectively terminate in

upturned toes

42 and 43 and are pivotally mounted upon the

shoes

36, 37 by horizontally disposed pivot pins, as 44, passing through the spaced members of the U-shaped heels in a direction crosswise oi the line of feed.

The foot-

plates

40, 41 are yieldingly depressed independently of each other by

springs

45 and 46 coiled about the auxiliary presser-

bars

34, 35, said springs beingv interposed between the upper guide-member 33 of the presser-foot shank and

collars

47 and 48 adjustably secured upon the

bars

34, 35 to yieldingly rest upon the lower guide-member 33 and thereby limit the downward movement of the foot-

plates

40, 41. The

collars

47, 48 each have adepending guide-nn 49 slidingly disposed in a suitable guide-slot in the lower guide-member 33, whereby the

bars

34, 35 are confined to vertically directed movements.

The foot-

plates

49, 41 are spaced from each other beginning from the

toes

42, 43 thereof to form a fabric-margin slot 50 which terminates at a point directly in front of the needle path, at which point the adjacent edges of the foot-plates curve inwardly into abutting relation to together form a split guide-web 51 which serves to deflect under the presser-foot the upwardly directed fabric margins passing through the slot50. The

, guide-web 51 which also terminates in front of the `needle-path is comparatively narrow in the 'formation to provide a needle-slot 53 in the presser-foot. The auxiliary foot 52 is preferably rigidly carried by a shouldered guide-bar 54 of which the lower portion is slidingly disposed in a p vertically directed aperture provided in a guideblock 55 upon the presser-foot shank 32. The reduced upper end of the guide-bar 54 is disposed within a screw-bushing-E adjustably threaded into the upper side of the guide-block 55, a spring 57 coiled about the reduced portion of the guidebar being interposed between the bushing 56 and the shoulder of the guide-bai'. The foot 52 has an upturned heel 58 which overlies a bent stopplate 59 secured by a screw 60 upon the rear side of the presser-foot shank 32, whereby downward movement of the foot 52 under the action of the spring 57 is limited. It will be observed that the crest 13 of the fabric-margin supporting member 12 upon the throat-plate rises substantially centrally of the presser-foot slot 50 and that it is in alinement with the auxiliary foot 52.

The machine is provided with a mechanism for trimming the upturned abric-margins passing through the presser-foot slot 50, said mechanism in the present instance including a horizontally disposed ledger-blade 61 and a horizontally vibratory cutting-blade 62 resting upon the ledger-blade, the cutting edges of said blades meeting in shearing relationship directly above the foot slot 50 and in advance of the guideweb 51. v

rIhe ledger-blade 61A is rigidly clamped in a split head 63 of a collar suitably secured upon the lower end of a vertically slidable rod 65 journaled in spaced lugs 66 formed on an auxiilary bracket 67 secured by screws as 68, upon a primary bracket 69 xed by screws, as 70, upon the rear side of the machine head 5. The rod 65 is restrained against oscillation about its longitudinal axis by a forked guide-collar 71 adjustably carried by said rod and embracing a guide-rib "I2 on the auxiliary bracket 67. Underlying the collar 71 is a lip 73 projecting laterally from a stopmember 74 secured for vertical adjustment upon the presser-foot supporting bracket 29, The stop-member limits the downward movement of the red 65, the adjustment being preferably such that the ledger-blade clcars the presser-foot plate 40 a suicient distance to allow for slight rocking movements of said foot-plate 40 about its pivotal support while riding uneven portions of the work. The stop-member 74 also functions to raise the trimmer-blades when the presser-foot is raised for insertion and removal of work. It will be observed that the described construction furthermore provides for adjustably raising and lowering the trimming position with respect to the work-support.

The cutting-blade 62 is rigidly clamped in a holder-collar 75 carried by a rod '76 slidably disposed in vertically alined apertures provided in spaced lugs 77, projecting forwardly from a rockarm 78. A spring 79 coiled about the rod '76 is interposed between the upper of the lugs 77 and a forked guide-collar 89 adjustably secured upon the rod above the lower lug 77, whereby the cutting-blade 62 is ,yieldingly urged into engagement with the ledger-blade 6l which it overlies. The rock-arm 78 has a split hub 81 clamped by a screw 82 upon a sleeve 83 journaled for oscillatory movements upon a vertically disposed ful- Crum-pin 84 xed in vertically spaced bearinglugs, as 85, upon the primary bracket 69. Projecting laterally from the upper end of the sleeve 83 is an arm 86 connected by an extensible link 87 with an arm 88 depending from one end of a horizontally disposed rock-shaft 89 journaled in a bracket 90 suitably secured to the underside of the machine bracket-arm 4. The other end of the rock-shaft 89 carries a crank-arm 91 pivotally connected with a pit-man 92 having a strap embracing an eccentric 93 upon the main shaft 14. It will be observed that the ledger-blade 61 and its supporting means can be removed from the machine independently of the other bladesupporting means by detaching the auxiliary bracket 67 'fromi the machine lli racl ;et-arr.fi, and that the entire trimmer-blade supporting mechanism can be removed as a unit fromthe machine `by detaching'the primary bracket 69: f

. supports during the passage oi the wort: without aecting the trimming position.` The side face 98 of the guard-block 95 adjacent thelslot 50 is gradually kcurved towards its rearward end to extend across said slot 59 and merge with the rearward wall of a slot 99 formed in the guardblock 94, whereby the Vtrimmed-od portion of the work is diverted laterally out of the seamline. Conforming with the diverting-surface curvature of said blocks and disposed directly thereabove in its operative positionso as to cooperate with said surface in deilecting the trimmed-oil, fabric margins, is a diverter-blade 100 having its shank 101 bent toclosely embrace the ledger-blade carrying collar. The ,curved shank 101 of the diverter-blade has ahorizontally elongated slot` 102 entered by the stop-screw 103 threaded into said collar and passing through a friction washer V194. This construction provides simple supporting means for the diverter-blade, permitting the blade to be readily swung intoand out of operative position. Because the function of diverter-r .blades of this character is well known, the drawingsshow the blade as swung into its ineiiective position to more yclearly illustrate the mechanism in part obscured by the blade in its operative position.

In order to join abricplies by a butt seam, the marginal portions oi such plies upon the work-supporting post are directed upwardly to pass through the presser-foot slot 59, whereupon the

shearing elements

61, 62 trim said margins and the trimmed-oir surplus is directed laterally out of the path of the needle yby the merging diverting surfaces of the guard-blocks 94, r95, aided by the diverter-blade 109. The trimmed- Lorf margins oi the plies are. then forced downwardly into abutting relation by the presser-foot.

guide-web 5l duringthe advance of the workv by the feeding mechanism. i

The abutting fabric plies are joined by a Zigzag-stitch seam formed bythe 'verticallyrecip- 'rocating and laterally vibrating needle 25 in conjunction with the loop-taker mechanism beneath the throat-plate. The presser-

foot plates

49, 41 are each capable oi riding `uneven portions lof the Work by reason of their pivotal and bodily yielding support upon the presser-foot body and can readily adapt themselves to differences in thicknesses of the fabric plies being joined. The

auxiliary foot 52 rides the'seam formed and, as

usual, opposes aportion of the feed-dog in the absence of work to yassist in chaining-oil.

. Having thus set forth thenature ofthe invention, what I claim herein is:-

` 1. A sewing machine comprising, in combination, stitch-forming mechanism including a reciprocatory needle, a work-support, work-feeding mechanism, v`a presser-footyieldingly opposed to the work-support having spaced work-engaging foot-plates between which upturned marginal portions oi material are, adapted to pass, a `trimming mechanism including cooperating shearing tion, stitch-forming.mechanism includinga reciprocatory needle,J afwork-support, work-feeding mechanism, a presser-bar, a presser-foot' carp ried by said presser-bar having adjacent kioctplates spaced at the forward end thereof to provide'betweenthem a slot adapted to receive'the upturned marginal portionsy of material, supporting means for said foot-plates upon the presser-bai providing for yielding movements lof the foot-plates independently or" each other in a direction away from the work-support, a trimming mechanism including cooperating shearing elements disposed kto trim said upturned marginal portions of material, means independent of the presser-foot for yieldingly depressing said shearing elements toward the work-support, and means movable with said presser-bar acting to limit the downward movement of said shearing elements to normally clear said foot-plates.

3. A sewing machine comprising, in combination, stitch-forming mechanism including a reciprocatory needle, a work-support, work-feeding mechanism, a presser-foot having adjacent work-engaging root-plates providing between them a fabric-margin receiving slot in advance or n the needle, supporting means for said foot-plates dependent or' the presser-root for yieldingly de- 120.

pressing said shearing elements towardthe worksupp'ort, and means acting to limit the downward movement of said shearing elements to normally clear said foot-plates. f

4. A sewing machine comprising, in combination, stitch-forming mechanism including a reciprccatory needle, a work-support, work-feedingmechanism, a presser-foot having adjacent foot-plates spaced at the forward end thereof to provide between them a slot adapted to receive the upturned marginal portions of material, supporting means for said foot-plates, providing for yielding movements thereof independently of each other in a direction away from the work-support, a trimming mechanism including cooperating shearing elements disposed above and normally clearing the foot-plates to trim said. upturned marginal portions of material, and guard-blocks upon said foot-plates provided with shearing-element clearance recesses and having abutting surfaces crossing said presser-foot slot in position to divert the trimmed-oir iabricmargins from the path of the needle.

5. In a sewing machine, in combination, a work-support, a presser-foot opposed to said work-support having spaced work-engaging portions providing a slot adapted to receive up-` turned marginal portions of material, 'a trim.- ming mechanism including a ledger-blade and a movable blade arranged in cooperating shearing relationship in position to trim said upturned marginal portions of material, ledger-blade 'sup porting means, a diverter-blade extending across said presser-foot slot having'its shank bent into circular form to embrace the ledger-blade supporting means whereby said diverter-blade may be, swung into and out of operative position, and means for limiting the movement of the diverterblade into operative position.

6. In a sewing machine, comprising, in combination, a frame including a fixed Work-support and an overhanging bracket-arm, stitch-forming mechanism, Work-feeding mechanism, a presserfoot Opposed to the Work-support having spaced work-engaging toes between which upturned marginal portions of material are adapted to pass, a trimming mechanism including a ledger- FREDERIC M. CARD.