US2851974A - Zigzag sewing machines - Google Patents

Description

Sept. 16, 1958 Filed Feb. 5, 1955 R. A. HAYES ZIGZAG SEWING MACHINES 5 Sheets-Sheet 1 Sept, 16, 1958 f R. A. HAYES 2,851,974

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Sept. 16,1958 R. A. HAYES 2,851,974 ZIGZAG SEWING MACHINES Filed Feb. 3, 1955 1 s Sheets-She et 3 FIGJO l l l ZIGZAG SEWING MACHINES Robert A. Hayes, Franklin Park, Ill., assignor to Union.

Special Machine Company, Chicago, Ill., a corporation of Illinois This invention relates to zigzag sewing machines and more particularly to machines of this character adapted to produce stitches of the 404 type, as defined by the Federal specifications. Such stitches are formed by two threads, one carried by a needle which is reciprocated vertically and is also shifted transversely of the line of feed, to provide the zigzag effect, and the other carried by a four-motion looper.

A primary object of the invention has been to provide simple, but effective, needle thread loop retaining means mounted directly on the looper to assure proper formation of the desired thread triangle as the needle is reciprocated in either of its positions transversely of the line of feed. Heretofore it has been considered necessary or desirable to provide a special loop retainer in association with the looper, this retainer being given four-motion movements, independently of the looper, to impart an elliptical path of movement to the loop retaining end thereof.

In accordance with the present invention the loop retaining function is achieved by a plurality of resilient elements mounted on the looper and arranged to partake of the movements of the latter. These elements, by a spring action, serve to retain the needle thread loop momentarily by friction at two different points along the length of the looper blade as the latter is being retracted. The arrangement is such that one' of the resilient elements serves to hold the limb of the needle thread loop which is on the forward side of the looper sufficiently close to the shank of the looper to insure proper passage of the needle, on its next descent, through the thread triangle. It is of particular importance as the needle is being recipro-cated along its righthand path, i. e. the path closer to the vertical standard, in the course of which the needle descends further from the point of the blade of the looper. After the needle thread loop is released by the resilient element described, upon the retraction of the looper, it is still retained by the second resilient element which frictionally grips the loop against the underside of the looper. The point at which the loop is held by this second resilient element is such as to insure continued downward movement of the needle in proper relation through the thread triangle. It will be appreciated that as the needle descends into cooperation with the looper it must clear the forward limb of the needle thread and subsequently clear the rearward limb of the needle thread. The two resilient elements serve to insure this proper coaction of the parts at all times.

The blade of the looper employed in accordance with the invention is preferably provided, intermediate its ends, with a lateral bend in a horizontal plane. Bending of the looper in this manner assists further in insuring the proper formation of the thread triangle for the desired descent of the needle through the triangle.

If desired the two resilient thread retaining elements may be, formed separately and mounted independently on the looper; however, they may be formed as a single unitary member.

Other objects, features, and advantages of the invention will appear from the detailed description of several illustrative embodiments of the same which will now be given in conjunction with the accompanying drawings, in which:

Fig. 1 is a view partly in elevation and partly in longitudinal vertical section through a sewing machine embodying the invention;

Fig. 2 is a detail view showing the improved looper construction in front elevation and in relation to the reciprocable needle;

Fig. 3 is a view similar to Fig. 2 but illustrates the parts in different relation assumed at a slightly earlier point in a cycle of operation;

Fig. 4 is a plan view of the looper when in the position shown in Fig. 2;

Fig. 5 is a plan view of the looper when in position shown in Fig. 3;

Fig. 6 is a plan view of the looper itself without the accessory devices;

Fig. 7 is an end view of the looper, with its accessory devices, as seen from the left in Fig. 2;

Fig. 8 is a view similar to Fig. 7 showing the looper with a needle guard attached thereto;

Fig. 9 is a front elevational view of the assembly shown in Fig. 8;

Fig. 10 is a front elevational view of a looper having a modified form of loop detaining means;

Fig. 11 is a plan view of the assembly shown in Fig. 9; Fig. 12 is a plan View of the assembly shown in Fig. 10;

Fig. 13 is an enlarged perspective view of a unitary resilient, thread retaining member, embodied in Fig. 10, having two thread retaining portions; and

Fig. 14 is an end view of the assembly shown in Fig. 10 as viewed from the right of the latter.

The invention has been disclosed herein as applied to a machine of the character disclosed in the Hayes and Reimer application, Serial No. 485,882, filed February 3, 1955, now Patent No. 2,792,797, dated May 21, 1957. This machine is adapted to produce zigzag stitches of the type designated 404 in the Federal Specifications. By appropriate adjustment of the needle bar swinging mechanism it may produce a straight line seam of the 401 type.

Referring to Fig. l, the machine comprises a hollow frame having a work supporting base portion 10, a vertical standard 11, and an overhanging arm 12 terminating in a needle head 13. A rotary drive shaft 14 is suitably journaled in the base and extends through the wall at the right end of the base and carries outwardly of the frame a combined handwheel and pulley 15 through which the machine may be driven. The stitch forming devices include a reciprocable needle bar 16 carrying a needle 17 at its lower end. Needle bar 16 is mounted for vertical reciprocation in bearing portions 18 and 19 of a downwardly extending arm 20 of an L-shaped lever which is pivoted at 21 adjacent the top of the needle head. This pivot as shown, is disposed just to the left of the path of travel of the needle bar. As explained in said Hayes, et al. application this enables the use of a full length needle bar and also brings about a more favorable coaction between the needle and the looper to be hereinafter described. Rigidly secured to the arm 20 is a horizontally extending arm 22 forming part of the L-shaped lever. Arm 22 extends longitudinally of the overhanging arm 12 to a point within the vertical standard adjacent the top of the latter.

For imparting vertical reciprocations to the needle bar there is provided a crank 23 on the shaft 14 having a. crank element preferably of the type disclosed 1n the. application of John Attwood, Serial No. 310,295, filed September 18, 1952, now Patent No. 2,729,179, dated January 3, 1956, with which cooperates a strap carried by the lower ends of a pair of connecting rods 24 the upper ends of which carry a strap cooperating with a ball pin 25. The latter projects outwardly from the end of a needle lever 26 rockably mounted by means of a shaft 27 extending transversely of the overhanging arm. At its left end the lever 26 is connected by a link 23 with a block 29 clamped upon the needle bar 16. As explained in said Hayes, et al. application, means are provided for rocking the L- shaped lever 20, 22 to swing the needle bar into alternate positions in a plane perpendicular to the line of feed. The arrangement is such that the needle bar is shifted in one direction during one revolution of the shaft 14 and in the opposite direction upon the next revolution of the, shaft 14 Forthis purpose the arm 22 of the L-shaped lever is provided with a ball pin 30 at its free end which cooperates with a strap at the upper end of an extensible connecting rod 31, the lower end of which carries a strap cooperating with a ball pin 32 projecting laterally from a rock member 33. This rock member forms a part of a unit designated 34 which is secured to the frame within the vertical standard and includes a cam (not shown) for rocking the member 33. Gear 35 in the unit 34 is connected with the cam mentioned and meshes with a pinion 36 connected to the shaft 14. This arrangement is such that the cam is given one. revolution for each two revolutions of the shaft 14.

Cooperating with the needle as it descends beneath the 'worlt supporting surface of the base is a looper 37. This is secured to. the upperend ofan arm 38 oscillatable about a pivot stud 39 extendingforwardly from a sleeve member 40. secured to a rock shaft 41. Oscillator-ymovements are imparted to the arm 38 about the stud 39 through a pitman or connecting rod 42- havinga strap at one end cooperating with a ball pin extending laterally from the arm 38, and. having, at its other end a strap cooperating, with a ball pin. carried by an arm 43. The latter is secured to a shaft 44 extending transverselyof the base of the frame and. is provided with a radially projecting arm or bolt 45. within. the vertical plane which contains the. axis of the. shaft 14. At the outer end of 'thisarm or bolt there, is provided a.ball pin.46'whicl1 is receivedbyastrap at the lower end: of av pitman 47: that has a strap at its upper end cooperating with a spherical crank element 48, on the shaft 14. Through the connections described loop-seizing. and. shedding movements are imparted to the looper 37. Needle avoid movements are.

imparted to the looper by rocking the shaft 41 in appropriately timed relation. to the reciprocation ofthe needle and the oscillation of: the. looper. For this purpose an eccentric 49 secured totheshaft' 14 cooperates with a strap 50 on a pitrnan, the lower end of. which is pivotally con nectedwith an arm. 51,-sec ured;to and extending rearwardly from the shaft41. Suitablemeans of the characterdisclosed in said Hayes, et al. application is. provided-for advancing the work. Suchmeans includes afour-motion' of the, looper 37 and associatedelements willbedescrib ed in further detail. Thelooper has a main body portion,

provided with a. downwardly extending shank 56 having a flat side.57,= this shank being arranged to copperate with a. corresponding opening in the upper end; of I the,

looper carrying arm 38? Extending laterally from the The work is urged into cooperation withthe feed upper end of the shank 56 is a horizontal support portion 58 of the looper from the outer end of which extends upwardly and rearwardly an arm 59 from which projects laterally the thread carrying and needle loop seizing blade 60 of the looper. The latter is preferably curved in a substantially horizontal plane or is provided with a bend at about its mid-point, as indicated at 61 in Fig. 6.

p This curvature or bending of the loop-seizing blade of the looper to direct its outer end away from the vertical plane through the longitudinal axis of the support portion 58 assists in creating the desired thread triangle, as will be explained hereinafter. A thread passage 62 provided through the arm 59 adjacent its upper end communicates with a slot 65 in the forward face of the blade of the looper for appropriate threading of the latter. Adjacent the free end of the blade 60 there is a thread passage 66 from the slot extending to the top surface of the blade from which the looper thread L extends to the work.

For the purpose of retaining the needle thread loop on the blade 60 of the looper in proper position to insure formation of the desired thread triangle for the passage of the needle upon its descent along either of its paths of travel, there is mounted on the looper suitable loop retaining means. This comprises a member, preferably formed of spring steel, having a base portion 67 secured by a screw 68 tothe support portion 58 of the looper, this. portion having a screwthreaded opening 69 therein to receive the screw. To provide for suitable adjustment of the. thread loop retainer the base portion 67' is provided with an: elongated arcua-te slot 70- cooperating with a pin 71' extending upwardly from the support 58. It will be apparent that the retainer may-be adjusted about the axis of'the screw- 68. and then secured in its adjusted position by tightening thescrew. Integral withthe base 67 is an upwardly and rearwardlyex-tendingarm 72 carrying at its upper end a rounded nose-like portion 73 which is urged resiliently against the forward face of the blade 60' of thelooper. As. best shown in Fig. 2', the point of engagement is about midwaybetween the ends of the blade and in, the upper. region thereof.

Another thread-loop detainer is also mounted on the main body ofthe looper. This has a base plate 74 provided;with a vertically elongated slot 75 (Fig. 7) through whichit is-adjustably mounted by meansof-a screw 76 onthe arm 59; of: the looper. A branch 77' of plate 74 extends upwardly and outwardly away from the plate to- The operation of the two loop-retaining elements 73' and 78.is1best showninFigs. 2'to 5. In-consideringthe showing of theelementsin these views it must be understood. that the needle 17: whichis carrying another-loop ofneedle threaddownwardly alongthe righthand path oftmovement; of the needle'was, during the formation of the preceding needlethread loop indicated by the limbs N and N' 1n the;d;rawings, moved downwardly alongits lefthandpath of movement. As the: needle, descendsbelow the throat plate the looper is being'retracted toward thought, as indicated by the, arrows, but the previous needle threadnloopis; being held well inwardly from the free endfloffth'e looper blade by the action of. the retainer 73, This retainer acts upon the limb N of the; needle thread'loop. After the. point. of the needle has descended-below the limb N"; the continued move: ment-of the looper toward'the right will'bring about the-.release-of the thread from-the'frictional retainer 73 so; that,theloop will assumethe position indicated in Fig. 2. ILiWlllibB 'notedzthatthe loop is still retained -by the, spring:ar n'.78;}so;-that;. ashthe needle continues to descend, it-wil1 -;Pfl$;in:fr0nt';of the limb N of the' previ- Gus needle thread loop. Thus, by the combined action of the two loop retainers 73 and 78 the proper positioning of the needle loop to provide the desired thread triangle is brought about. As hereinabove indicated, this is of particular importance when the needle is descending along its righthand path of travel in the course of forming zigzag stitches.

In Figs. 8, 9, and 11 there is shown the same type of looper, having two separate needle loop retaining means and also having applied to the looper a suitable needle guard 80 positioned appropriately in front of the blade of the looper. This needle guard has integrally connected therewith a hat base portion 81 superimposed upon the base portion 67 of the first described loop retaining element. The needle guard is secured to the looper by means of the same screw 68 by which the thread loop retainer is attached. As best shown in Fig. 11, the outer end of the needle guard is curved outwardly away from the loop-seizing blade of the looper to provide the desired needle guard action.

Figs. 10, 12, 13 and 15 show a modified form of loop retainer which incorporates in a single member the two loop retaining elements. This member, illustrated in perspective in Fig. 13, has a base plate 82 provided with an opening 83 for the reception of a screw 84 by means of which the combined loop retainer may be secured to the arm 59 of the looper. It will be understood that the latter has a screw threaded opening to receive the screw threaded shank of screw 84. Preferably the opening 33 is of somewhat larger diameter than the shank of the screw to enable slight adjustment of the combined loop retainer. A curved spring arm or portion 85 of the retainer extends laterally from the base plate beneath the blade 60 of the looper and engages the under face of the blade at approximately the same point as the arm 78 of the second retainer described in relation to Fig. 2. The point on the arm 85 which so engages the underface of the looper is indicated at 86 in Fig. 13. Beyond this the arm is curved downwardly as indicated at 87 to provide clearance for the needle thread loop to pass between the retainer and the under surface of the blade 60 of the looper. An upwardly projecting part 88 of the arm 85 having outwardly curved Wings 89, as best shown in Fig. 12, is adapted to engage the front face of the loop-seizing blade 60 of the looper. Its point of contact with such front face coincides substantially with that of the nose 73 of the retainer shown in Fig. 4. Due to the springiness of the arm 85 and the upward extension 88 a suitable frictional contact is provided with the indicated surfaces of the looper blade to retain the needle thread loop in the same manner as the element 73 and 78 of Fig. 2, at the points described, in the course of a cycle of operation of the machine.

It should be understood that the blade 60 of the looper, in the modified construction shown in Figs. 10, 12, Band 14, may be curved or bent in a substantially horizontal plane in the same manner as the blades of the earlier forms described. Also a needle guard, similar to the guard 89, may be mounted on the support portion 58 of the looper body.

While several illustrative embodiments of the invention have been described in some detail, it will be understood that various changes may be made in the construction and arrangement of the various element and parts thereof within the scope of the appended claims. The provision of means for frictionally detaining the needle loop at two spaced points along the looper blade makes unnecessary the provision of a separate four-motion loop retainer even in the formation of relatively wide gauge zigzag stitches.

What is claimed is:

1. In a sewing machine a looper assembly comprising a looper having a main body portion and a loop seizing blade projecting laterally from said body portion, and resilient means carried by said body portion in fixed relation thereto having parts thereof yieldingly urged into engagement with said blade and arranged to grip and frictionally retain a needle thread loop on said blade at two spaced points intermediate the ends of said blade. 2. In a sewing machine a looper assembly comprising a looper having a main body portion and a loop seizing blade projecting laterally from said body portion, and resilient means carried by said body portion in fixed relation thereto having parts thereof yieldingly urged into engagement with said blade and arranged to grip and frictionally retain a needle thread loop on said blade at two spaced points intermediate the ends of said blade, said means having a part arranged to urge a portion of said thread loop against a side face of said blade and another part arranged to urge a portion of said thread loop against the under surface of said blade.

3. In a sewing machine a looper assembly comprising a looper having a main body portion and a loop seizing blade projecting laterally from said body portion, and a single resilient member carried by said body portion in fixed relation thereto having parts thereof yieldingly urged into engagement with said blade and arranged to grip and frictionally retain a needle thread loop on said blaide at two spaced points intemediate the ends of said blade.

4. In a sewing machine a looper assembly comprising a looper having a main body portion and a loop seizing blade projecting laterally from said body portion, and resilient means carried by said body portion arranged to engage and frictionally retain a thread loop on said blade at two spaced points intermediate the ends of said blade, said means having a part arranged to urge a portion of said thread loop against a side face of said blade adjacent the top thereof and another part arranged to urge a portion of said thread loop against the under surface of said blade.

5. In a sewing machine a looper assembly comprising a looper having a main body portion and a loop seizing blade projecting laterally from said body portion, said blade being bent laterally in a substantially horizontal plane, and resilient means carried by said body portion in fixed relation thereto having parts thereof yieldingly urged into engagement with said blade and arranged to grip and frictionally retain a needle thread loop on said blade at two spaced points intermediate the ends of said blade.

6. In a sewing machine a looper assembly comprising a looper having a main body portion and a loop seizing blade projecting laterally from said body portion, resilient means carried by said body portion in fixed relation thereto having parts thereof yieldingly urged into engagement with said blade and arranged to grip and frictionally retain a needle thread loop on said blade at two spaced points intermediate the ends of said blade, and means for adjustably securing said resilient means to said body portion.

7. In a zigzag sewing machine having work feeding devices arranged to feed work pieces in a predetermined direction, a reciprocable needle bar carrying a thread bearing needle, a carrier for said needle bar arranged to shift the same back and forth transversely of the direction of feed, and a four motion, thread carrying looper cooperating with said needle to form a zigzag line of stitches, said looper comprising a body portion and a loop seizing blade projecting laterally from said body portion, the combination of resilient means mounted on said body portion of said looper in fixed relation thereto and having spaced needle thread loop engaging parts urged yieldingly against said blade at points spaced along the length thereof to retain the loop momentarily at said points.

8. In a zigzag sewing machine having work feeding devices arranged to feed Work pieces in a predetermined direction, a reciprocable needle bar carrying a thread bearing needle, a carrier for said needle bar arranged to loop seizing blade projecting laterally from said body portion, the combination of resilient means mounted on said body portion of said looper in fixed relation thereto and having spaced needle thread loop engaging parts urged yieldingly against said blade at points spaced along the length thereof to retain the loop momentarily at said points, said points at which said parts of said resilient means engage said blade being. so disposed as to retain the loop in a position to form a triangle with the looper thread and said blade through which the needle may descend.

9. In a zigzag sewing machine having work feeding devices arranged to feedwork pieces in a predetermined direction, a reciprocable needle bar carrying a thread bean'ng needle, a carrier for said needle bar arranged to shift the same back and forthtransversely of the direction of feed, and a four motion, thread carrying looper cooperating with said needle to form a zigzag line of stitches, said looper comprising a body portion and a loop seizing blade projecting laterally from said body portion, the combination of resilient means mounted on said body portion of said looper in fixed relation thereto and having spaced needle thread loopengaging parts urged yieldingly against said blade at points spaced along the length thereof to retain the loop momentarily at said points, and means for adjustably securing said resilient means to said body portion of the looper.

10. In a zigzag sewing machine having work feeding, devices arranged to feed work pieces-in a predetermined direction, a reciprocable needle bar carrying a thread bearing needle, a carrier for said needle bar arranged to shift the same back and forth transversely of the direction of feed, a. four motion, thread carrying looper cooperating with said needle to form a zigzag line of stitches, said looper comprisingia-body portion and a loop seizing blade projecting laterally from said body portion in a direction transverse to the direction of feed, and means for oscillating said looper in said transverse'direction to seize and shed needle thread loops, said blade having a bend therein to provide a free ended portion directed in part in the: direction of feed, the combination of resilient means mounted on said body portion of said looper in fixed relation thereto and-having a part thereof urged yieldingly against said blade at a point inwardly of said free ended portion thereof and another part urged yieldingly against said blade ata point along said free endedportion thereof.

11. In. a zigzag sewing machine having work feeding devices arranged to feed work pieces in a predetermined direction, a reciprocable needle bar carrying a thread bearing. needle, a carrier for said needle bar arranged to shift the same back and forth transversely of the direction of feed, a four motion, thread carrying looper cooperating with said needle to form a zigzagv line of stitches, said looper comprising a body portion. and a loop seizing blade projecting laterally from said body portion in a direction transverse to the direction of feed, and means for oscillating said looper in said transverse direction to seize and shed needle thread loops, said blade having its free ended portion directed in part in the direction of feed, the combination of resilient means mounted on said body portion of said looper and having a part thereof urged yieldingly against said blade. at a point inwardly of said free ended portion thereof and another part urged yieldingly against said blade at a point along said free ended portion thereof, said first mentioned part of said resilient means engaging said bladealong a vertical face thereof and said other part of said resilient means engaging said blade along the under surface thereof.

12. In a zigzag sewing machine having Work feeding devices arranged to feed work pieces in a predetermined direction, a reciprocable needle bar carrying a thread bearing needle, a carrier for said needle bar arranged to shift the same back and forth transversely of the direction of feed, a four motion, thread carrying looper cooperating with said needle to form a zigzag line of stitches, said looper comprising a body portion and a loop seizing blade projecting laterally from said body portion in a direction transverse to the direction of feed, and means for oscillating said looperin said transverse direction to seize and shed needle thread loops, thecombination of resilient means mounted on said body portion of said looper in fixed relation thereto and having spaced needle thread'loop engaging parts urged yieldingly against said blade at points'spaced along the length thereof to retain the loop momentarily at said points at different times during the movement of said blade transversely across-the line of feed.

References Cited in the file of this patent UNITED STATES PATENTS 929,698 Onderdonk Aug. 3, 1909 1,127,755 Gray Feb. 9; 1915 1,227,891 Dahl May 29, 1917 2,345,327 Clayton Mar. 28, 1944'

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