US1542871A - Presser mechanism for sewing machines - Google Patents

Description

June 23, 192s; 1,542,811

A. GRIEB PRESSER MECHANISM FOR SEWING MACH-INES Filed Jan. a, 1925 2 sheetslsheet 1 MTORNEY v June 23,*-1925 A. GRIEB PRBssnn mcHANIsM For: SEWING MACHINES Filed Jan. 1925 2 sheets-sheet 2 ATI'GRNEY Patented June 23, 1925.

UNITED STATES y APATENT OFFICE.

ALFRED GRIEB, OF ELIZABETH, NEW JERSEY, ASSIGNOR TO THE SINGER VIYLNUFAC- TUBING COIVIPANY, F ELIZABETH, NEW JERSEY, A CORPORATION OF NEW JERSEY.

PRESSER l:Li/IECHANSII FOR SEWING MACHINES.

Application filed January 8, 1923. Serial No. 611,227.

To all whom t may concern.'

Be it known that I, ALFRED Gnin, a citiy Zen of the United States, residing at Eliza-Y beth, in the county of Union and State of New Jersey, have invented certain new and useful Improvements in Presser Mechanisms for Sewing Machines, of which the following is a specification, reference being had therein to the accompanying drawings.

This invention relates to improvements in pressure-foot mechanisms for sewing machines and has for an object to provide improved means for controlling the threadchain formed in the operation of chainstitch machines in the absence of work and particularly for controlling the thread-chain Y until the thread is anchored in the work by the formation of an initial stitch of a seam.

Another object of this invention is to reduce wear of the parts and power required to operate sewing machines more particularly adapted for stitching thick materials or heavy work.

The invention has for a further object to provide a pressure mechanism permitting ready insertion of thick materials between the presser-foot and cloth-plate of the machine while the latter is in operation and without loss of control of the thread-chain.

lith these and other objects which will be apparent fromv the following description and claims, the present invention in its preferred embodiment comprises a presser mechanism in which two presser-bars are journaled for endwise movement independently of each other in the head of the sewing machine bracket-arm and are each spring-pressed independently of the other in the direction of the machine cloth-plate. One of these presser-bars carries a primary presser-foot having a foot-plate supported to tilt upon an axis substantially transverse to the direction of feed and the other press- 7' er-bar carries an auxiliary presser-foot preferably rigid with the presser-bar. TheV auxiliary presser-foot is disposed entirely rearward of the needle and is opposed to a p0rtion of the feed-dog adapted to act upon and feed the thread-chain formed during the operation of the machine in the absence of work. The primary presser-foot vis disposed adjacent to and projects forwardly beyond the needle and the auxiliary foot and is opposed to the main portion yof the feed-dog, whereby said primary presserfoot may yield vertically when the'work is inserted thereunder and fed to the needle, while the auxiliary foot nevertheless maintains its control of the thread-chain by reason of the independent supports of these presser-feet. Furthermore, by disposing the auxiliary presser-foot entirely in the rear of the needle, it is not raised from the thread-chain by the work until after the thread is anchored in the work.

While the auxiliary presser-foot is springpressed into direct engagement with the portion of the feed-dog opposed thereto, the movement of the primary presser-foot toward the throat-plate under theaction of its depressing spring is limited a predetermined extent by suitable means whereby in the absence of work the feed-dog is not required to act against the heavy pressure of the main presser-foot at each feeding stroke.

In the accompanying drawings, Fig. 1 is a front side elevation of a portion of a sewing machine embodying the present improved presser-mechanism. Fig. 2is a front end elevation and Fig. 3 a rear side elevation of the head portion of the sewing machine. Fig. `4 is atop plan view of the presser-feet and throat-plate.

Referring to the drawings, the preferred embodiment ofv thel present improvement is illustrated in connection with a sewing machine comprising a cloth-plate 1 from which rises the standard 2 of a tubular .overhanging bracket-arm 3 terminating in a head 4. Journaled in suitable bearings provided in the overhanging arm is aneedlebar reciprocating rock-shaft 5 upon which is secureda crank-arm 6 of which the free end is connected by means of a link 7 with a stud S on a collar 9 suitably secured upon a needle-bar 10. The needle-bar 10 is journaled for endwise reeiprocation in bearings provided in the head 4 and carries a needle 11 for coaction in the formation of stitches with any usual construction of chain-st itch looper beneath the cloth-plate 1. Secured upon the machine frame by means of screws as 12 is a throat-plate 13 provided with an elongated needle-'aperture 13 and with elongated feed-slots as 14 upon opposite sides of the path of movement of the needle 11 and with a short feed-slot 15 intermediate the feed-slots 1 4 and directly in the rear of the needle in the line of feed. Pro- CII jecting through the feed-slots during its worlcfeeding movements is a feed-dog of which the outer elongated sections 16 operate in the slots 14 and a short intermediate or chain-feed section 17 operates in the slot 15.

Opposed to the feed-dog sections are main and auxiliar-y presser-feet of which the main presser-foot comprises a vertically slotted shank 18, the flattened lower end of which extends within a channel 19 providedv on the upper face of a foot-piece 2O pivotally connected to the flattened portion of the shank by means of a transverse screw-pin 21. The rearward end of the foot-piece 2O everlies one of the slots 14 in the throat-plate and is extended laterally at 22 across the needlepath to overlie the other of the slots 14, a needle aperture 28 being provided in this lateral extension of the foot-piece 20. The shank 18 of the main presser-foot is securec by means of a screw 24 upon the lower end of a presser-bar 25 journaled for endwise movements in suitable bearings provided in the head 4. rThe upper end of the presserbar 25 is engaged .one end of a flatspring 26 to yieldingly urge the main presser-foot in a direction toward the throat-plate 13, the other end of the spring 2.6 being supported upon a pin 27 on a 'lug 28 kon the machine frame. 1n order to regulate the pressure exerted by the spring "2G there is provided the usual adjusting screw 29 adapted to be maintained in adjusted position by means of a lock-nut 3 Adjustably secured by means of `a screw 31 upon the presser-bar 25 and adapted to bear against the top of the head 4 is a collar which limits the downward movement of the bar under the `action of the spring 2G. Preferably this col'lar viQ so adjusted upon the presser`bar that in its lower limit of movement the presserfoot carried by the 'har y25 just clears the feed-dog during the work advancing movements of the latter in the absence of work. r)This obviates the 4necessity of lifting the presser-foot, in the absence of work, by the feed-dog Aduring j each of its feeding` vn'i-ovesnents, the pressure of the spring 26 being necessarily considerable for lheavy work. This saves not only in power required to operate the machine, but also :in wear of the parts.

ALocated 'directly rearward of the 'later-al extension 22 of the main p resserefoot a-nd overlying the short feed-slot 15 as weil'l Vas the rearward portion of one of the slots 14 is `an auxiliary presser-foot 33, of which one of the functions ii-s Yto ooact with the chain-feed .section 17 of the feed-dog in 'carrying Aaway l'the tthread-chain'f-rom the stitching point. The lausiliary foot 33 is preferably rigid with its shank 84 which is secured "by `means 'of a screw 35 upon the lower end of a presser-bar 8G. The presser bar 36 is journaled for endwise movement in suitable bearings provided in the head 4 and independently of the main presser-foot carrying bar 25. Likewise is the auxiliary presser-bar 86 spring-pressed toward the throat-plate independently of the springpressure of the presser-bar 25. To this end the upper end of the bar 36 is engaged by one end of a fiat-spring 37 of which the other end is seated upon a pin 38 on a lug 39 on the machine frame. rlhe pressure exerted by the spring 37 may be regulated by an adjustable screw 40 held in adjusted position by means of a lock-nut 41. 1t will be observed vthat the presser-bars 25 and l3G are disposed in a plane substantially at right angles to the direction of feed.

Suitably secured vupon the presser-bars and 36 are collars 42 and 43 having rearwardly. projecting lifter- lugs 44 and 45 disposed in frictional engagement with each other and guided by the walls of a slot 46 provided in the head 4 to prevent yaxial rotation of the presser-bars. The lifter Vlugs 44 and 45 are adapted to be engaged by a shoulder 47 on a lifter-link 48 pivoted by means of a scr-ew 49 upon 4a lifter-lever 50 fulcrumed upon a stud-pin 51 threaded into Vthe head 4. Downward movement of the lever is limited -by a pin 52 on the head 4. The lower end of the lifter-link 48 is maintained lin the slot 46 lby means of a plate 53 bridging the slot and secured upon the head 4 by fasten-ing screws as 54.

A sewing machine embodying a presser mechanism such as is herein described is particularly adapt-ed for closing the mouths of filled sacks, the materials of which are often extremely heavy and are frequently used in connection with liningsacks. 1n the use of :filled sack sewing apparatus, the sewing machine lis prefers-.bly kept in continuous operation to speed production, the machine chaining-off from one sack to another. It is evident-that to properly chain oi'fli, the thread-chain must be'controlled until the initial stitch of a seam is anchored in the work. llf-hilo thread-chain controlling devices have heretofore been provi-ced in prior constriuritions, the insertion lof leavy materials lluider the presserfoot desti eyed the 4effectiveness 4of such -controlling -d vices. 1n accordance with the present improved mechanism, the main presser foot may yield to .any thickness of work without hav-ing any effect .upon the auxiliary presserfoot until .the needle has penetrated the work, after which the auX- il-iary presser-foot performs the saine function as the main presser-foot in feeding 4the work. After the seam is finished, so long as the work is under the presser-feet the thread-chain is properly Idirected .away from the needle-aperture and thereafter the :auX-

iliary foot immediately assumes control thereof, while the primary presser-foot remains clear of the feed-dog for the purpose described. i

Having thus set forth the nature of the invention, what I claim herein is l. In a sewing machine, the combination with stitch-forming mechanism including a reciprocatory needle, and feeding mechanism including a chain-feed-dog disposed to act upon the seam formed by said needle, of a presser mechanism comprising a pivotally supported main presser-foot projecting forwardly beyond said needle, means urging said presser-foot to yieldingly engage the work, an auxiliary presser-foot coacting with said chain-feed-dog and disposed entirely rearward of said needle to engage the work subsequently to the formation of an initial stitch therein whereby the feed of the thread-chain is under constant control by said auxiliary presser-foot until the thread is anchored in the work, said main presser-foot extending rearwardly of the needle to substantially the same extent as the auxiliary foot, and means urging said auxiliary presser-foot to yieldingly engage the work independently of said main presser-foot.

2. A cloth-presser mechanism for sewing machines comprising main and auxiliary presser-feet, means for supporting said main presser-foot to yieldingly engage the work in advance of said auxiliary presser-foot, and means for supporting said auxiliary foot at the side of a portion of the main presser-foot to yieldingly engage the work on the line of seam-formation subsequently to the anchoring of an initial stitch therein, said auxiliary presser-foot supporting means being independent of said main presser-foot to permit introduction of the work thereunder without disturbing the control by said auxiliary foot of the chain of thread being formed preparatory to the stitching of the work.

3. In a sewing machine, the combination with an overhanging arm, a reciprocatory needle, and a feed-dog having a chain-feedportion effective upon the work in rear of said needle, of a cloth-presser mechanism comprising independent presser-bars journaled for endwise movement in said overhanging arm, yielding means for depressing said bars, a presser-foot carried by one of said bars disposed entirely rearward of the needle to coact with the chain-feed-portion of said feed-dog, and a presser-foot pivotally sustained by the other bar and disposed to engage the work at the side and in advanceV of the other presser-foot.

4. The combination in a sewing machine including a reciprocatory needle, a .throatplate, and a feed-dog projected through said throat-plate during its feeding movement,

of a main cloth-presser, means yieldingly urging said cloth-presser in a direction toward said throat-plate, means independent of said feed-dog for limiting the movement of the cloth-presser toward the throat-plate in the absence of work, an auxiliary clothpresser, and means yieldingly urging said auxiliary cloth-presser into engagement with the throat-plate in the lowered position of said feed-dog.

5. In a sewing machine, in combination two presser-feet, yielding means for depressing said presser-feet into engagement with the work, a stop device for limiting the work-engaging movement of one only of said presser-feet to prevent contact thereof ywith the machine parts therebeneath in the absence of work, and means under manual control for simultaneously lifting said presser-feet into inoperative position.

6. In a sewing machine, the combination with stitch-forming mechanism including a reciprocatory needle, and feeding mechanism including a chain-feed-dog disposed to act upon the seam formed by said needle, of a presser mechanism comprising a main presser-foot having a needle-aperture, an auxiliary vpresser-foot coacting with said chain-feed-dog and disposed directly rearwardly of the needle path of movement and at the side of a portion of said main presserfoot, means for supporting said presser-feet independently of each other, means for yieldingly depressing said presser-feet independently of each other to Aengage the work whereby the thread-chain is controlled by said auxiliary presser-foot regardless of the thickness of the work under the main presser-foot, and means under manual control for simultaneously lifting said presserfeet into an inoperative position.

7. In a sewing machine, the combination with stitch-forming mechanism including a reciprocatory needle, and feeding mechanism including a chain-feed-dog disposed to act upon the seam formed by said needle, of a presser mechanism comprising a main presser-foot, an auxiliary presser-foot coacting with said chain-feed-dog and disposed to engage the work subsequently to an initial penetration of the work by said needle, means for supporting said presser-feet independently of each other, means for yieldingly depressing said presser-feet independently of each other to engage the work, and means independent of said feeding mechanism for limiting the movement of said main presser-foot under the action of its yielding depressing means in the absence of the work.

8. In a sewing machine, the combination with stitch-forming mechanism including a reciprocatory needle, and feeding mechanism including a chain-feed-dog disposed to act upon the seam formed by said needle, of a presser mechanism comprising a main needle, means for Sup-porting Said presserfeet independently Aof ieach other, means for yieldngly depressing seid presser-feet i11- dependently of each other to engage bhe Work, means independent ,of said feeding mechanism for limiting ythe movementv of said main presser-foot under the action of its yielding .depressing means in the absence of the Work, and means under manual control `for lsmnlua neonsly lifting 4said presserfeet into an inopenatve position.

In testimony whereof, have signed my name .to ,this specification.

ALFRED GRIEB.

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