US2969028A

US2969028A - Uncurling device for sewing machines

Info

Publication number: US2969028A
Application number: US543113A
Authority: US
Inventors: John M Washburn
Original assignee: Merrow Machine Co
Current assignee: Merrow Machine Co
Priority date: 1955-10-27
Filing date: 1955-10-27
Publication date: 1961-01-24
Anticipated expiration: 1978-01-24

Description

Jan 24, 1961 J. M. WASHBURN UNCURLING DEVICE FOR SEWING MACHINES 5 Shee ts-Sheet 1 Filed Oct. v, 1955 Inventor: c/bhnM Was-lab urn His/1 torneys Jan. 24, W61 ,J. M. WASHBURN 2,969fi28 UNCURLING DEVICE FOR SEWING MACHINES Filed Oct. 27, 1955 5 Sheets-Sheet 2 Inventor: cfohnMTVashlaurn/ By M W Jama 24, 196E Filed 001;. 2'7, 1955 5 Sheets-Sheet 3 [nven tor: Jbhn M Washburn .299 M am Patented Jan. 24, 1961 UNCURLING DEVICE FOR SEWING MACHINES John M. Washhurn, West Hartford, Conn., assignor to The Merrow Machine Company, Hartford, Conn, a corporation of Connecticut Filed on. 27, 1955, Self. No. 543,113 8 Claims. (Cl. 112-18) This invention relates to sewing machine feed mechafabrics having a tendency to curl along their edges.

Before marginal or overedge stitching is applied to such fabrics, the curl adjacent the fabric edge must be fiattened and needle, that is, formed and anchored in the work. A primary object of the present invention is to provide in a sewing machine a device for uncurling and holding a margin of the work material in flattened and unstretched condition as it is fed to and receives the needle.

Another object is to provide a device for uncurling and other feed devices to produce varying degrees of differential feed of material. In the achievement of action to the work if the fabric such action desirable. Another feature of the invention resides in mechanism for manipuwill become apparent from the following detailed descriptron taken in conjunction with the accompanying drawings.

Fig. 2 is a fragmentary plan view partly in section of the mechanism shown in Fig. 1;

Fig. 3 is an elevation view of the mechanism shown in Fig. 1 as seen from the right;

Fig. 4 is a view similar to Fig. 2 showing a modified form of uncurling blades and needle plate;

Fig. 5 is a fragmentary plan view showing work with stitches applied thereto and with some of the stitches supported by a stitch finger comprising a part of an uncurling device;

Fig. 6 is a view similar to Fig. 1 but showing additional parts whereby uncurling blades operate to alternately grip and release the work; and

Fig. 7 is an elevation view partly in section of the mechanism shown in Fig. 6 as seen from the right.

Referring first to Figure 1, the machine frame 1 supports a main drive shaft 2 operable to actuate various movable parts of the sewing machine including a needle carrier 3 and a feed dog carrier 4. A curved needle 5 may cooperate with either an upper looper 6 or with both such a looper 6 and a lower looper 7 to form overedge stitches respectively of two or three threads. A needle or throat plate 8 is slotted to accommodate a feed dog 9 supported by feed dog carrier 4 and operate substantially in rear of needle 5. Opposed to feed dog 9and needle plate 8 is the usual presserfoot 10.

For actuating feed dog carrier 4 to move feed dog 9 in four-motion feeding movements, conventional mechanism is employed which includes a link such as 12. A similar link 13 is driven by an eccentric 14 on shaft 2 and is pivotally connected at its opposite end to a carrier 2'15 by means of stud 16. Carrier 15 is slidably supported for oscillating reciprocatory movement upon

guide rods

18 and 19 which are fixedly mounted upon a bracket 20 secured to machine frame 1 by

screws

21 and 22. A standard 23 is extended upwardly from carrier 15 to support the fabric uncurling and holding device indicated generally at 24.

Uncurling device 24 includes a separator blade 25 formed at the distal end of an arm 26 extending from standard 23. Each of a pair of uncurling elements indicated generally at 28 includes a yoke 29 having an uncurling blade 30. Yoke 29 includes opposite branches .31 and 32 which are employed to pivotally mount yoke 29 upon

respective pins

33 and 34 projecting from standard 23, thereby allowing uncurling blades 30 to be pivoted toward and away from the intermediate separator blade 25.

Separator blade 25 and uncurling blades 30 extend along the path in which material is fed to the stitch forming mechanism. Material being fed is gripped between uncurling blades 3@ and separator blade 25 (see Fig. .5) along the marginal edge of the material. The oscillating reciprocatoly motion imparted to carrier 35 and blades 25 and 3t) enable the blade to uncurl and fiatten the material as it is moved toward the needle while the gripping force exerted between uncurling blades 30 and separator blade 25 permits slippage or relative movement between the work material and the gripping blades upon movement of the blades away from the needle. Since different thicknesses of material, or types of fabric, may require greater or lesser gripping force, adjustment of the gripping force exerted by the movable uncurling blades 30 is obtained by positioning nuts 35 upon a threaded rod 36 fixedly mounted in lug 37 which projects from standard 23 to vary the force exerted by compression springs 38 which are sleeved upon threaded rod 36 between lug "37 and the respective uncurling elements 28. Jam nuts 35 are also mounted upon threaded rod 36 to maintain nuts 35 in their adjusted position. By suitable location of nuts 35, the gripping force exerted upon material between blades 30 and separator blade 25 may be regulated to an amount which is sufficient to uncurl and flatten the work material during the right to left stroke of carrier 15 while at the same time permitting slippage between the

blades

30 and 25 and the work material when the carrier is driven in the opposite direction by link 13. In order that the spacingbetween separator blade 25 and blades .30 may be temporarily enlarged to introduce work material between the blades, finger grasps 40 are extended fromthe forward end of uncurling elements 28.

As shown in Figs. 1, 2 and 5 each of uncurling blades 30 is provided with a stitch finger 41 extending rearwardly at one side of needle 5. Work is fed directly from uncurling device 24 to finger 41 which receives and initially supports enclosing stitching 42 (see Fig. 5).

A modified arrangement for supporting stitches during their formation is shown in Fig. 4 and includes a stitch of the work material to which stitching is to be applied.

The amount of travel of either carrier 4 or is determined by the amount of eccentricity of the eccentrics employed to actuate the

respective links

12 and 13. When the eccentrics are alike feed dog 9 and uncurling device 24 move respective distances that are equal. When the eccentrics are different the respective feeding elements move a different amount and effect a difierential feeding action.

In the feed mechanism shown in Figs. 1, 2 and 3, uncurling device 24 engages the work throughout the cycle of reciprocation. During the feeding stroke there is little or no relative movement between the uncurling device and the work but during the retractive stroke, when fabric uncurling is accomplished, slippage is required between the uncurling device and the work. This action is satisfactory with fabrics of certain character but if the work fabric is, for example, of a highly elastic nature it is desirable that the uncurling elements grip the work only during the feeding portion of the cycle and release it during retractive movement.

Structure for accomplishing the desired gripping and releasing action of the uncurling elements is shown in Figs. 6 and 7. In this embodiment, each uncurling blade 30 has formed thereon a lug 50 which extends into a path followed by a cam 51. Cam 51 is located at the distal end of an arm 52 which is secured to link 13 by screw 53.

Counter clock-wise rotation of eccentric 14 as shown by arrow X in Fig. 6 moves link 13 and carrier 15 to the right as shown by arrow Z and imparts a retractive movement relative to needle 5 to uncurling device 24. At the same time rotary oscillation of link 13 about pin 16 swings cam 51 slightly in a counter clock-wise direction as shown by arrow Y and forces lugs 50 apart, thus causing uncurling blades 30 to swing away from separator blade and release their grip on the work material. When link 13 moves to the left, cam 51 moves in a direction away from lugs and uncurling blades 30 move to resume their gripping hold on the work by action of springs 38.

It is distinctly to be understood that the invention is not limited to the exact details of construction hereinbefore described and illustrated in the accompanying drawings as these details may be modified without departure from the scope of the invention as defined by the following claims.

Having thus described the invention what I claim is:

1. In a sewing machine having a frame, a stitch forming mechanism, a feed dog mechanism for feeding material to said stitch forming mechanism, and means for driving the aforementioned mechanisms in synchronized movement; a fabric uncurling and holding device comprising a carrier mounted upon said frame for movement toward and away from said stitch forming mechanism along the path in which material is fed to said stitch forming mechanism, means connecting said carrier and 'said driving means for driving said carrier in cyclic oscillating movement synchronized with movement of said feed dog mechanism, means upon said carrier including opposed blades extending along the path of feed for engaging and flattening the marginal edge of work material presented to said stitch forming mechanism, means resiliently biasing said blades toward each other to grip the marginal edge of work material therebetween, and

means on said connecting means for moving said blades toward and away from each other to respectively grip and release work material in synchronism with the cyclic movement of said carrier.

2. In a sewing machine having a frame, a stitch forming mechanism, a feed dog mechanism for feeding material to said stitch forming mechanism, and means for driving the aforementioned mechanisms in synchronized movement; a fabric uncurling and holding device comprising a carrier mounted upon said frame for movement toward and away from said stitch forming mechanism along the path in which material is fed to said stitch forming mechanism, means connecting said carrier and said driving means for driving said carrier in cyclic oscillating movement synchronized with movement of said feed dog mechanism, opposed blades mounted on said carrier and extending along the path of feed for flattening the marginal edge of work material presented in said stitch forming mechanism, means biasing said blades toward each other to exert a pressing force upon said work material, and means for adjusting said pressing force to permit relative movement between said blades and said work material during movement of said carrier away from said stitch forming mechanism.

3. In a sewing machine having a frame, a stitch forming mechanism, a feed dog mechanism for feeding material to said stitch forming mechanism, and means for driving the aforementioned mechanisms in synchronized movement; a fabric uncurling and holding device comprising a carrier mounted upon said frame for movement toward and away from said stitch forming mechanism along the path in which material is fed to said stitch forming mechanism, means connecting said carrier and said driving means for driving said carrier in cyclic oscillating movement synchronized with movement of said feed dog mechanism, opposed blades mounted on said carrier and extending along the path of feed for flattening the marginal edge of work material presented to said stitch forming mechanism, means biasing said blades toward each other to exert a gripping force upon said work material, and means for retracting said blades to release the grip of said blades upon said material during movement of said carrier away from said stitch forming mechanism.

4. In a sewing machine having a frame, a needle plate mounted on said frame. a stitch forming mechanism operable adjacent the forward end of said plate, a feed dog mechanism located rearwardly of said stitch forming mechanism and operable to feed work material thereto, and means for driving said mechanisms in synchronized movement; a fabric uncurling and holding device comprising a carrier slidably mounted upon said frame in front of the forward end of said plate, means connecting said carrier to said driving means for driving said carrier in reciprocatory movement toward and away from the forward end of said plate along the path in which material is fed to said stitch forming mechanism, opposed blades mounted upon said carrier and extending along said path in which material is fed, resilient means urging said blades toward each other to grip work material therebetween, and means for regulating the gripping force exerted by said blades upon said material whereby relative movement may occur between said blades and said material during movement of said carrier in a direction away from said stitch forming mechanism.

5. In a sewing machine as recited in claim 4, wherein the ends of said blades remote from said needle plate are shaped to uncurl the marginal edges of work material entering the space between said blades when said blades are moved relative to said work material.

6. In a sewing machine having a frame, a stitch form ing mechanism, a feed dog mechanism for feeding work material to said stitch forming mechanism, and means for driving the aforementioned mechanisms in synchronized movement; a carrier movably supported upon said frame for movement toward and away from said stich forming mechanism along the path upon which material is fed to said stitch forming mechanism, opposed uncurling blades mounted upon said carrier for movement toward and away from each other, means including an eccentrically driven link for oscillating said carrier along said path in synchronism with movement of said feed dog mechanism, and means mounted upon said link for moving said uncurling blades toward and away from each other.

7. In a sewing machine having a frame, a stitch forming mechanism, a feed dog mechanism for feeding material to said stitch forming mechanism, and means for driving the aforementioned mechanisms in synchronized movement; a carrier mounted upon said frame for recip rocatory movement toward and away from said stitch forming mechanism along the path upon which material is fed to said stitch forming mechanism, opposed uncurling blades mounted upon said carrier for movement toward and away from each other, resilient means biasing said uncurling blades toward each other, a link pivotally coupled at one end to said carrier, eccentric means rotatable by said driving means coupled to the other end of said link, an arm fixedly mounted upon said link, and means on said arm movable between said blades during one portion of a cycle of movement of said link to move said blades away from each other and movable to a position clear of said blades during the remaining portion of said cycle to permit said blades to move toward each other to grip work material therebetween.

8. In a sewing machine, stitch forming implements including a needle, fabric feeding means substantially in the rear of said needle, fabric uncurling blades in front of said needle extending along the path in which fabric is fed to said needle, means for driving said feeding means and said needle in synchronized movement, means coupling said fabric uncurling blades to said drive means to impart advance and retractive strokes of said blades along said path in synchronism with the movement of said feeding means and said needle, and means on said coupling means for moving said blades toward each other to grip fabric therebetween during the advance stroke of said blades and for moving said blades away from each other to release the fabric during the retractive stroke of said blades.

References Cited in the file of this patent UNITED STATES PATENTS 645,539 Allen Mar. 20, 1900 730,945 Merrow June 16, 1903 1,288,735 Stieg Dec. 24, 1918 1,546,202 Chenoweth July 14, 1925 2,208,992 Lewis July 23, 1940 2,339,574 Kurcera et al. Jan. 18, 1944 2,669,203 Hiltbrunner et a1 Feb. 16, 1949 FOREIGN PATENTS 345,070 Great Britain Mar. 19, 1931 142,416 Sweden July 23, 1953