US2730060A - Thread control mechanism for sewing machines - Google Patents

Thread control mechanism for sewing machines Download PDF

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US2730060A
US2730060A US323098A US32309852A US2730060A US 2730060 A US2730060 A US 2730060A US 323098 A US323098 A US 323098A US 32309852 A US32309852 A US 32309852A US 2730060 A US2730060 A US 2730060A
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thread
looper
takeup
overedge
needle
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US323098A
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Schoij Edgar
Lippere Salvatore
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Union Special Machine Co
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Union Special Machine Co
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    • D—TEXTILES; PAPER
    • D05—SEWING; EMBROIDERING; TUFTING
    • D05B—SEWING
    • D05B51/00—Applications of needle-thread guards; Thread-break detectors

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  • the present invention relates to sewing machines and more particularly to thread control in industrial sewing machines used in the production of three thread overedge stitches along the free edges of a plurality of superimposed pieces of work or along the free edge of a single piece of work.
  • the thread handling requirements are to deliver the correct amounts of each thread at the correct times and under the correct tensions to the respective stitch forming instrumentalities. It is particularly important in the formation of certain types of stitches, such as the Federal Standard Stitch Type 504, that the tension of the threads be such that, at the formation of a stitch, they do not dig into or distort the work. In other words, it is desirable that a relatively relaxed stitch be formed. At the same time it is desirable that the threads be firmly drawn and uniformly positioned to pro vide a neat effect and to leave no loose loops of thread at the edge of the work.
  • a primary object of the invention has been .to provide improved thread control means for a threethread overedge sewing machine.
  • Another object of the invention has been to provide thread. control devices so constructed and coordinated as to be capable of producing a neat and firm, but relatively relaxed, three thread stitch which will not dig into or otherwise distort the edges of the work.
  • a still further object of the invention has been to pro vide coordinated thread control devices capable of producing a relatively elastic chain.
  • an overedge sewing machine having a reciprocable needle, an under looper, an overedge looper, takeup mechanism for operating on threads to the needle and loopers, and driving connections for actuating the needle, the loopers and the takeup mechanism, with a first threadguiding means for separately guiding the looper threads from a supply into association with the takeup mechanism therefor, and second thread guiding means for separately guiding the looper threads from the takeup mechanism therefor to the respective loopers, the latter thread guiding means being constructed and arranged to provide substantial resistance to passage
  • a United States Patent 0 of both looper threads between the takeup mechanism and the loopers and the driving connections beingarranged to cause the takeup mechanism to engage the looper threads as the loopers are operated away from the stitch forming point, whereby a substantial decrease in looper thread tension between the takeup mechanism and the looper is created during the interval in which the takeup mechanism is imparting takeup action to the looper threads.
  • novel means are provided for drawing needle thread and looper threads from the supply, this means being arranged to draw from the supply the amount of under looper thread desired for each stitch before completely drawing from the supply the corresponding amounts of overedge looper thread and needle thread.
  • the novel thread takeup means permits adjustment of the location of the purl on the edge of a stitch or seam by moving the thread eyelets but without adjustment of the thread tension means.
  • Fig. l is an end elevational view of an overedge sewing machine constructed in accordance with the invention, a portion of the machine frame being broken away to illustrate the thread handiing mechanism;
  • Fig. 2 is a view, partly in front elevation and partly in vertical section, of a portion of the overedge sewing machine of Fig. 1;
  • Fig. 3 is a plan view of a corresponding portion of the sewing machine of Fig. l, certain parts being broken away for clarity of illustration of other parts;
  • Fig. 4 is a detail view of one of the thread tension devices embodied in the machine
  • Fig. 5 is an exploded view of the thread tension device shown in Fig. 4, showing the details of its component parts;
  • Fig. 6 is a perspective view of a thread guiding member embodied in the illustrative sewing machine
  • Fig. 7 is a plan view of a portion of the sewing machine showing particularly the looper thread takeup eyelets and the under looper thread guiding eyelets;
  • Figs. 7a and 7b are end views of certain of the parts shown in plan in Fig. 7;
  • Fig. 8 is a detail view, in rear elevation, of the needle carrying arm and associated parts
  • Fig. 9 is a detail view, in side elevation, of the needle arm, the looper thread takeup and cast-off means and related parts, the moving parts being shown at a time in the cycle of operation of the machine corresponding to the commencement of the needle downward stroke;
  • Fig. 10 is a detail view similar to Fig. 9 with the parts in the positions assumed when the looper thread cast-01f is about to push the under looper thread ed the looper thread takeup;
  • Fig. 11 is a perspective view of the looper thread castoti and the looper thread take-up showing the under looper thread as it is being forced off the takeup and the overedge looper thread engaged by the takeup;
  • Fig. 12 is a perspective view of the parts shown in Fig. 11 at a point in the cycle immediately after the under looper thread has been cast-off while the overedge looper thread is still engaged by the looper thread takeup;
  • Fig. 13 is a view, partly in front elevation and partly in section, of the parts shown in Fig. 12;
  • Fig. 14 is a perspective view of a thread stand arranged
  • the overedge sewing machine illustrated is of the type disclosed in the copending patent application of Ned L. Wallenberg et al., Serial No. 196,104, filed November 17, 1950.
  • a frame (Figs. 1 and 2) which is of relatively low construction and is provided with a fiat bottom and a curved sloping top.
  • This frame provides an enclosed chamber or housing portion 21 (Fig. 2) having a flat removable bottom plate 22 secured to the frame by screws or the like.
  • Chamber 21 is shown only partially in the drawings. For a detailed description of the mechanisms contained therein reference may be had to the above mentioned Wallenberg et al. application. Chamber 21 is arranged to retain lubricant to a suitable level for the purpose of providing automatic lubrication of the major wear receiving parts of the mechanism, in the manner set forth in said pending application.
  • a vertical wall 23 at the left end of enclosed chamber 21 has an extension 24 at its lower end which partially encloses certain of the stitch forming and work feeding devices which must be provided exterior of the enclosed chamber 21. Further partial enclosure of the chamber above extension 24 is provided by a cloth plate 25 having downwardly extending apron portions which normally conceal the stitch forming and work feeding devices.
  • a main drive shaft 26 for the operating parts of the machine extends longitudinally of the frame, substantially. along a line about midway between the front and rear walls and midway between the planes of the bottom plate- 22 and the work supporting surface of cloth plate 25. Adjacent its left end, shaft 26 is supported by a pair of bearing sleeves 27 and 28 suitably mounted in the wall 23 of the frame. As shown, the bearing sleeve 28 is preferably mounted in a retainer 29 having a press fit in. an enlarged recess in the outer face of the wall 23.
  • a support member (Figs. 1, 2, 3 and 14) mounted on frame 20 is arranged to carry three thread tension devices 41, 42 and 43 for overedge looper thread 0, needle thread N, and under looper thread U, respectively.
  • Tension device 41 as shown in Figs. 1, 2, 4 and 5, comprises a; screw 44having a knurled head 45 and a threaded stem portion 46. This screw passes through a hole in the top ofv support 40, through a bushing washer 47, through two mating tension discs 48 and 49 and through a tension spring 50.
  • Threaded stem portion 46 engages a threaded hole in thecenter of a circular spring supporting plate 51 and is seated in an unthreaded recess or hole provided therefor in the-base 52 of support member 40.
  • Plate 51 is provided with a slot 51A in one side thereof adapted to mate-with a pin 53.which is rigidly set in the base 52. Pin 53 prevents plate 51 from turning with screw 44, so that as the. screw is turned, by means of its knurled head 45, the plate 51 is raised or lowered, depending upon which way thescrew 6: is turned. Raising of the plate 51 compresses spring and hence forces the tension discs 48 and 49 under greater pressure into engagement with each other and, against the bushing washer 47. Similarly, lowering of:plate 51 decreases the tension of spring 50, reducing the force exerted. on tension. discs 48 and 49. The tension discs regulate the tension on the thread passing between them, and this thread tension is adjusted by turning head, 45.
  • Tension devices 42 and 43 may be identical with the device 41 described.
  • Support member 40' performs an important. function with respect to each of the tension devices: in, that the side plate of member 40 acts as a shield covering. the tension. springs on the side facing the thread supply (Fig. 1), so that the thread cannot be caughtand broken in one of the. springs.
  • the protection afforded thereby is of great significance at high sewing speeds. because, at such speeds, a substantial whipping action occurs between the thread supply and the tension discs.
  • the three threads 0'; N, and U come from their respective supply sources, which might be, for example, thread cones, and pass between the respective tension discs, as shown most clearly in Fig. 1 with respect to overedge looper thread 0.
  • Inlet and outlet eyelets 54 and 55, respectively, are provided in member 40 for guiding each thread to and from a respective pair of tension discs, the thread being passed between the tension discs somewhat to one side of the associated screw 44.
  • needle thread N passes through an adjustable stationary guide eyelet 6% (Fig. 1), through a takeup 61 adjustably mounted on a trimmer bar 62 by means of a screw 63 cooperating with an elongated slot 64 in the takeup, thence successively through two eyelets in a stationary guide bar 65 extending from a plate 65a adjustably mounted on the machine frame by means of screws 66 cooperating with slots 67 (Fig. 1), and finally to the eye of a curved needle 68.
  • Needle 68 is carried in a socket 68' on an arm 69 mounted on and oscillated by a rock shaft 70.
  • Rock shaft 7% is operated by suitable connect-ions (not shown in the drawings) with main shaft 26. Details of these connections, as well as other connections to the main shaft 26 to be set forth hereinafter, may be found in the aforementioned Wallenberg et al. applicatron.
  • the needle thread N tightens up and thread is drawn from the associated thread cone on the down stroke of the needle 68.
  • the takeup 61 is normally carried as high on the. trimmer bar 62 as possible without causing threadto be drawn from the cone on the up stroke of the needle and of the trimmer bar.
  • the principal purpose in providing the takeup 61 is to facilitate adjustment of needlethread N under various sewing conditions. Normally it only takes up a nominal amount of needle thread slack when the needle rises and delivers a nominal amount of needle thread when the needle'descendn'the operationof the trimmer bar being suitably coordinated with the. needle carrying arm and the takeup 61 being suitably adjusted on the trimmer bar to accomplish this.
  • takeup 61 may be adjusted on trimmer bar 62 so that it will take and give more thread. In fact, takeup 61 may be adjusted to draw needle thread from theneedle thread cone should this prove desirable in meeting certain sewing conditions.
  • Trimmer bar 62 which carries takeup 61, also carries a movable trimmer blade which is adapted to cooperate with a stationary trimmer blade (not shown) in shearing the edges of the work between successive advances, as is fully described in the said Wallenberg et al. application.
  • Trimmer bar 62 is carried on a rock shaft 76, suitably connected by means (not shown) to main shaft 26.
  • overedge or upper looper thread 0' coming from, its' supply source passes through tension device 41 and then goes directly through aligned overedge looper thread takeup eyelets 8 0 and 80' and then to and through a; vertical tube 81 mounted on the machine frame and finally to the eye of an overedge looper 82 which is mounted: for reciprocation and oscillation on a looper shaft 83.
  • Looper 82 is given a' combined r'e'ciprocatory and oscillatory movement, by suitable connections such" as shown in said Wallenberg et al. application, which imparts to the active end of the looper a spiral or'helical path.
  • Overedge looper 82 is adapted to pass its thread through a loop of the under looper thread and then carry the loop of its own thread upwardly and over the edge of the work into the path of the curved needle 68 while the latter is in its uppermost position. Upon a subsequent oscillation of the needle 68,v its thread will be carried through the loop of the-overedge looper thread.
  • Thread takeup eyelets 80. and 80. are formed, respectively, in parallel bars 84 and 84' adjustably mounted on a bracket 85 by means of screw 86 acting in elongated slot 87 and in a threaded hole through base or connecting sleeve 88 for the bars 84 and 84' (Fig. 6).
  • Base 88 and bars 84 and 84 form a generally U-shaped bracket with aligned eyelet holes 80 and 80, as is shown most clearly in Fig. 6.
  • Bracket 85 is adjustably mounted on the machine frame by suitable means shown in Fig. 7.
  • a foot portion of the bracket is provided with an elongated slot 85a through which is passed a screw 85b for fastening the bracket to the frame.
  • the guide bars 84 and 84' may be adjusted both rotatably about the axis of the screw 86 and bodily with the latter in the slot 87
  • the bracket 85 may be adjusted bodily and even angularly on the frame to the extent permitted by slot 85a and screw 85b. This enables correct positioning of the eyelets 80 and 80 for all sewing conditions.
  • the under or lower looper thread U extends from its thread supply through tension device 43, through a stationary eyelet 95 (Figs. 2 and 3) adjustably mounted on the machine frame 20, through aligned under looper 5 thread takeup eyelets 96 and 96' (Figs. 1 and 13) and through spaced stationary eyelets 97 and 98 to an under looper 99.
  • Eyelets 96 and 96' are formed in a bracket similar to the one shown in Fig. 6 and comprising apair of parallel bars 100 and 100 formed on a base 101 having a hole adapted to receive a screw 102 which cooperates with an elongated slot 103 in bracket 85.
  • bars 100 and 100' are rotatably and laterally adjustable within bracket 85 and may be adjusted with the latter in the same manner as bars 84 and 84'.
  • Eyelets 97 and 98 are formed in end projections of a thread supporting member 104 rigidly mounted on an adjustable guide member 105, as shown in Fig. 7.
  • Guide member 105 together with a second adjustable guide member 106 maintains feed bars 107 and 108 in place.
  • Guide 106 is mounted on the machine frame by screws 109 and 110 which act in an elongated slot 111 in a laterally extending arm of guide 106, as best shown in Fig. 7a. Provision of elongated slot 111 permits lateral adjustment of guide 106.
  • Guide 105 is mounted on the machine frame by a screw 112 acting in an elongated slot 113 in guide 105, as best shown in Fig. 7b. Provision of elongated slot 113 permits lateral adjustment of guide 105. It is evident that lateral adjustment of guide 105 will also provide a slight lateral adjustment of eyelets 97 'and 98.
  • Under looper 99 which carries thread U, is mounted for reciprocation on a rod 110 actuated from main shaft 26 by suitable connections, not shown in the drawings but disclosed in said Wallenberg et a1.
  • Looper 99 executes a simple reciprocatory movement along a straight line.
  • Rod 110 is disposed at an acute angle, preferably between 20 and 30 to the horizontal, and serves upon reciprocation to carry the thread-carrying eye of the under looper 99 from a position at the left of the path of the needle and some distance below the cloth plate to a point at the right of the path of the needle and substantially in the plane of the cloth plate 25 (Fig. 2).
  • the looper 99 is adapted to pass its thread through the loop of needle thread which is, at this time, presented below the cloth plate.
  • Takeup member 115 which is mounted on and oscillated by the needle bar rock shaft 70.
  • Takeup member 115 which is best illustrated in Figs. 8 through 13, comprises an arm 116 clamped to the shaft 70, adjacent the needle carrying arm, and a bifurcated member 117 fastened to arm 116 by means of a screw 118.
  • the branches of member 117 are divided into straight takeup portions 119 and 119', which extend radially in relation to shaft 70, and curved or bent reentrant portions 120 and 120' which provide cast-off edges at the lower ends of portions 119 and 119 and surfaces to receive the cast-off thread.
  • Portions 119 and 119 of takeup member 115 are arranged to move along an arcuate path between eyelet bars 84 and 84' and between eyelet bars 100 and 100',
  • a castoif member 125 is adjustably mounted on bracket by means of a screw 126 acting in an elongated slot 127 in a rearward extension of member 125. This extension is clamped within a slotted downward extension 128 of bracket 85, the inner branch of which is threaded to receive the screw 126.
  • Cast-01f member 125 extends upwardly and outwardly to act between the forked takeup portions 119 and 119' of arm 117.
  • takeup member engages under looper thread U between eyelets 96 and 96 and carries the same on takeup portions 119 and 119 (Fig. 11) until thread U is urged off of the same by the lower edge of cast-off member 125.
  • Cast-off member 125 casts thread U off the lower edges of takeup portions 119 and 119 and into the curved portions and 120' as the takeup reaches about the position indicated in Figs. 10 and 12. It will be observed that the arrangement of cast-off member prevents interference with overedge looper thread 0 by under looper thread U. As takeup member 115 rises, the overedge looper thread 0, which is normally resting on the upper edges of cast-off member 125 (Fig.
  • bracket 85 is adjustable relative to the machine frame.
  • Looper motions will be considered forward when a looper enters a thread triangle or loop and backward when a looper sheds thread.
  • the overedge looper 82 just reaches its uppermost and foremost position as the needle starts to descend, so that the needle will enter a thread triangle formed by overedge looper 82 as the latter starts its return from this position.
  • the under looper 99 has started its backward motion and sheds the needle loop seized thereby in the preceding cycle.
  • the looper thread takeup member 115 being fixed to the needle bar rock shaft 70, starts its upward movement when needle 68 commences its downward travel.
  • needle thread takeup 61 which is mounted on trimmer bar 62, starts its downward motion.
  • the looper thread takeup 115 engages the under looper thread U.
  • Under looper thread U starts to be drawn from its supply while it is still around the overedge looper 82.
  • Most of the thread is drawn as under looper thread U approaches and comes off the point of overedge looper 82, although a little more thread is drawn as the under looper thread is pulled to the edge of the Work.
  • Looper thread takeup 115 engages the overedge looper thread 0 as the overedge looper 82 moves away from the line of stitch formation.
  • the under looper thread U is cast off from the overedge looper 82, pulled down to the stitch and then is cast off takeup portions 119 and 119'.
  • the under looper 99 starts forward to enter the needle thread loop and the overedge looper tive. supply. cones. stops as the needlelfiS reaches the. bottom of. its. stroke;
  • The-under looper 99' enters the needle thread. loop as. the needle 68 begins to rise and the looper thread takeup 1 15. is starting its backward motion.
  • the overedge looper 82 enters the lower looper thread triangle, as shown in Fig; 2.
  • the various stitch forming elements continueon to their original positions preparatory to commencement of another stitch forming cycle. Feeding of the work, which may be performed as described in the said Wallenberg et al. application, takes place when the needleis out of the Work.
  • overedge looper thread from tension. device 41. to the eye of overedge looper 82 may conveniently be divided into two portions, one extending from tension device 43 to-talzeup-mernber 115 .and the other from takeup member 115 to the overedge looper 82.
  • a substantial frictional resistance to thread passage is provided in the latter portion because ofthe thread guiding surfaces provided therein and particularly because of thenumber, extent, and angular disposition ofthe. surfaces encountered. More specifically, during a portion of the ascent of takeup member 115, thread 0 is drawn from the associated supply cone or bobbin, through v tension device 41, eyelet 55 and eyelet 80 to takeup member 115.
  • the thread controlling means from the takeup to the stitch are so arranged for the overedge looper thread that at each thread contacting surface thereof when thread is being drawn from the supply, i. e., as the needle is approaching the bottom of its stroke, the tension is reduced on the side closest the.
  • overedge looper thread tension at the stitch is preferably made about one third of the overedge looper thread tension adjacent the takeup member. Decrease in thread tension at overedge looper 82 is also aided by the fact that over-edge looper 82 is moving away from the stitch point.
  • tension at the stitch is higher than at the tension discs, then a variation at the tension discs will result in a correspondingly higher variation at the stitch.
  • a desirable effect of the reduction in thread tension atthe stitch and the permissible increased. tension at the tension discs 48 and 49 is the formation of more uniform stitches.
  • a decreasein tension of thread 0 from takeup member 115. to1 overedge looper 82 reduces thread breakage and permits the use of poorer grade threads. If the tension were to increase rather than decrease, the tension atthe tension discs would have to be substantially lower than is. desirablev inorder. to preventexcessive; threadtbreakage".
  • the thread stand illustrated has been found well suited. for supplying the three threads to the overedge sewing machine.
  • the thread stand comprises an upright supporting rod 140 which is mounted at its lower end, in suitable socket 141 provided in a table top 1.42.
  • An adjustable clamp 143 is mounted on the upper end of a rod 1.40..
  • a hori zontal arm or rod 144 is supported in clamp 143'. Adjacent, either end; and at the center of rod. 144: are mounted.
  • each of rods 151 is provided adjacent each extremity thereof with a collar 152. secured to rod 151 by set screws 153.
  • Slidably mounted on each rod 151 between the limits provided by collars 152 is a wood block 154 having a generally frustro-conical shape. Thread cones O, N, and U which supply, respectively, threads 0, N, and U, may be placed upside down on the respective blocks 154. By jamming the thread cones on the respective blocks and against the upper collars 152, the cones are frictionally held to the blocks.
  • a C-shaped horizontal guide member 155 is mounted in rod 144 and provided with thread guiding holes 156, 157 and 158 each disposed below a respective thread cone and adapted to receive and guide threads 0, N, and U respectively.
  • an overedge sewing machine having a main drive shaft stitch forming means including a needle, an overedge looper and an under looper, and connections from said shaft for operating said stitch forming means in coordination to form overedge stitches
  • the combination of thread controlling devices for controlling the delivery of threads from sources of supply to said stitch forming means said devices including a plurality of thread guiding means for each of the threads delivered to the needle, the overedge looper and the under looper, a plurality of thread takeup members arranged to act upon the several threads in the course of their delivery to said stitch forming means, and connections from said shaft for operating said takeup members in such timed relation as to completely draw the thread delivered to said under looper from its source of supply before the threads delivered to said needle and said overedge looper are completely drawn from their sources of supply, said takeup members being arranged to draw all of said threads from their sources of supply during the latter part of the downward movement of the neddle.
  • an overedge sewing machine having a main drive shaft stitch forming means includedin a needle, an overedge looper and an under looper, and connections from said shaft for operating said stitch forming means in coordination to form overedge stitches
  • the combination of thread controlling devices for controlling the delivery of threads from sources of supply to said stitch forming means said devices including a plurality of thread guiding means for each of the threads delivered to the needle, the overedge looper and the under looper'and a plurality of thread takeup members arranged to act upon the several threads in the course of their delivery to said stitch forming means, connections from said shaft for operating said take up members, and thread tensioning means acting upon the several threads between their sourses of supply and said takeup members, said devices and said means for operating said stitch forming means and said take up members being constructed and arranged to exert the primary takeup action on the overedge looper thread as said looper is moving away from the point of stitch formation and as the path of said thread is being shortened from the point of stitch formation to the nearest guide for said thread, so
  • An overedge sewing machine comprising a main shaft, a reciprocable needle, an under looper, an overedge looper, means for drawing needle thread and looper threads from a supply, said means serving to draw off all of said threads from their sources of supply during the latter part of the downward movement of the needle and being arranged to completely draw from the supply the amount of under looper thread desired. for each stitch before completely drawing from the supply the corresponding amounts of overedge looper thread and needle thread, said means including a takeup member for operating on both of the looper threads, and driving connections from said shaft for actuating said needle, said loopers and said takeup member to effect said timing of their actions.
  • An overedge sewing machine comprising a reciprocable needle, an under looper, an overedge looper, means for drawing needle thread and looper threads from a supply, said means serving to draw thread from the supply for said needle and said loopers as the needle is descending and being arranged to draw from the supply the amount of under looper thread desired for each stitch before drawing from the supply the corresponding amounts of overedge looper thread and needle thread, and said means including a needle thread takeup element arranged to cooperate with said needle in drawing thread from said supply, a takeup member having a takeup portion for engaging and drawing from said supply said under looper thread and said overedge looper thread and having a cast-off thread receiving portion, said takeup member being arranged to draw most of said under looper thread from said supply before drawing said overedge looper thread from said supply and to completely draw said under looper thread from said supply before completely drawing said overedge looper thread from said supply, a cast-off member arranged to cooperate with said takeup portion to cause said under looper thread to be disengaged from said takeup portion and
  • An overedge sewing machine comprising a reciprocable needle, an under looper, an overedge looper, means for drawing needle thread and looper threads from a supply, said means serving to draw thread from the supply for said needle and said loopers as the needle is descending and being arranged to draw from the supply the amount of under looper threaddesired for each stitch before drawing from the supply the corresponding amounts of overedge looper thread and needle thread, and said means including a needle thread takeup element arranged to cooperate with said needle in drawing thread from said supply, a takeup member having a takeup por: tion for engaigng and drawing from said supply said under looper thread and said overedge looper thread and having a cast-01f thread receiving portion, said takeup member being arranged to draw most of said under looper thread from said supply before drawing said overedge looper thread from said supply and to completely draw said under looper thread from said supply before completely drawing said overedge looper thread from said supply, a cast-off member arranged to cooperate with said takeup portion to cause said under looper thread to be
  • An overedge sewing machine comprising a recipro cable needle, an under looper, an overedge looper,means fondrawingneedle: threadand loopenthreads from .a supplyasaidsmeansaserving: to ,drawthread; from, the supply.
  • nism first: thread guidingmeansifor separately guiding thezlooperythreads fromthezsupply intoassociation with saidztakeup; mechanism, and secondthread guiding means. for separately guiding the;looper threads from said takeupmechanism to the respective loopers, said latter tthread:
  • guiding-;mea-nsz being constructed and arranged to provide substantialiresistance --to passage, of overedge looper thread between said;.takeup.mechanism and the overedge looper. andbeing; arranged to deliver thread to the overedge looper-alongsuch agpath that said looper yields thread as saidtakeup mechanism, is imparting its primary takeup action to the overedge looper thread, and said driving connections being so timed as to cause said takeup mechanism, to; engage the overedge looper thread as said overedge looper is operated awayfrom the stitch forming point whereby a substantially lower tension is imparted tothe-thread deliveredto theoveredge looper at the point of stitchzformation than is, imparted thereto adjacent said takeup mechanism during the interval inwhich said takeupmechanism is-imparting takeup action to said overedge looper thread.
  • An overedge sewing machine comprising a reciproeableneedle,anunderlooper, an overedge looper, atake up mechanism for operating on threads to said loopers, driving connections-for actuating said needle, said loopers and. said, takeup mechanism, first thread guiding means for separately guiding the looper threads from a supplyinto. association with said takeup mechanism, and second thread, guiding means for separately guiding the looper threads from said takeup. mechanism to the respective loopers, said. latter thread guiding means having a plurality of thread contacting surfaces and being constructed and arranged to provide substantial resistance to passage of.
  • overedge looper thread between said takeup mechanism and the overedge looper and being arranged to deliver thread to theoveredge looper along such a path that saidlooper yields, thread as said takeup mechanism is imparting its primary: takeup action to the overedge looper, thread, and said driving connections being so timed. as to cause said takeup mechanism to engage theoveredge looper tthread and to, draw the same over the associated thread contactingsurfaces of said second thread guiding means in directions. away from the stitch when said overedge looper thread is being drawn from its 1 29 31 h tionship of the several parts being such that. the: overedge looper thread tension adjacent said takeup mechanism .is approximately three times the tension therein at the stitch.
  • An overedge sewing machine comprising a reciprocable needle, an under looper, an. overedgelooper, a takeup member for operating on threads to said loopers, drivingconnections; for actuating: said needle, said loopers and said takeup member, first thread guiding means for separately guiding the looper threads from a supply into association with said takeup member, and second thread guiding means for separately guiding the looper threads from said takeup member to the respective loopers, said latter thread guiding means being constructed and ar-. ranged. to provide; substantial resistance to passage ofthe looper threads between said takeup member and the re-.
  • spective loopers and being arranged to, deliver threads to said, loopers along such paths that said loopers yield thread as said takeup member is, imparting its primary takeup action, to the looper threads, and said drivingconnections being so timed as to, cause said takeup member 12 to engage;v the overedge; looper threadassaid overedge looper-is operated away. fromthe. stitch forming point whereby asubstantial decrease, in overedgelooper thread tension between saidtakeupmember andsaidoveredge looper is provided during the interval in which said take:
  • up member is imparting takeup action to saidioveredgev looper thread.
  • An overedge sewingmachine comprising a recipro-v cable needle, an under looper, an overedgelooper, aitaker. up member for operatingon threads to said loopers, driv-, ing connections for actuating said needle, said loopersand said takeup member, first thread guiding means fonsepa; rately'guiding the looper. threads from supply. means into association with said takeup member, and second thread. guiding means for separately guiding the looper. threads from. said takeupmernber to the. respective loopers, saidj latter thread guiding means. comprising a. plu'raliti of thread guiding surfaces arranged. to carry thev overedge looper thread and to guidethe same along.
  • An overedge sewing-machine comprising arecipro: cable needle, an under looper, an overedge looper, a takeup member for operating on threads to said loopers, saidtakeup member having a takeup portion for engaging said looper threads and for drawing the same from a supply and having a cast-off thread'receiving portion, a cast-off member so disposed relative to said takeup member as to disengage the under looper thread from said takeup portion as said member is moving in its thread take up direction and causing the same to be engaged by said cast-off thread receiving portion after the amountof under looper thread desired for a stitch has been drawn from the supply, driving connections for actuating said needle, said loopers and said takeup member, first thread guiding means for separately guiding the looper threads from said supply into association with said takeup member, and second thread guiding means for separately.
  • said latter thread guiding means being provided with a plurality of thread guiding surfaces constructed and arranged to, provide substantial resistance to passage of overedge looper thread between said takeup, member and the overedge looper, and said driving. con nections being so timed as to cause said takeup.
  • An overedge sewing machine comprising a reciprocable needle, an under looper, an overedge looper, a takeup member for operating on threads to said loopers, driving connections for actuating said needle, said loopers and said takeup member, first thread guiding means for separately guiding the looper threads from a supply into association with said takeup member, said first thread guiding means including a first takeup eyelet for the overedge looper thread and a second takeup eyelet for the under looper thread, said takeup member being arranged to engage said looper threads adjacent the respective takeup eyelets and having a generally straight takeup portion for engaging the looper threads and drawing the same from a supply and having a re-entrant cast-off thread receiving portion, a stationary cast-off member disposed adjacent the respective takeup eyelets and so arranged relative to said takeup member as to cause disengagement of the under looper thread from said takeup portion as said member is moving in its thread take up direction and to cause the same to be engaged by said cast-off thread receiving portion after the amount of under
  • An overedge sewing machine comprising a recipro- 14 cable needle, an under looper, an overedge looper, a takeup member for operating on threads to said loopers, driving connections for actuating said needle, said loopers and said takeup member, first thread guiding means for separately guiding the looper threads from a supply into association with said takeup member, said first thread guiding means including a first takeup eyelet for the overedge looper thread and a second takeup eyelet for the under looper thread, said takeup member being arranged to engage said looper threads adjacent the respective takeup eyelets and having a generally straight takeup portion for engaging the looper threads and drawing the same from a supply and having a re-entrant cast-off thread receiving portion, a stationary cast-off member disposed adjacent the respective takeup eyelets and being so arranged relative to said takeup member as to cause disengagement of the under looper thread from said takeup portion and to cause the same to be engaged by said cast-oif thread receiving portion after the amount of under looper thread desired for
  • An overedge sewing machine comprising a reciprocable needle, an under looper, an overedge looper, takeup means for operating on threads to said loopers, driving connections for actuating said needle, said loopers and said takeup means, first thread guiding means for separately guiding the looper threads from a supply into association with said takeup member, adjustable thread tensioning means associated with said first thread guiding means for tensioning the looper threads between the supply and said takeup member, and second thread guiding means for separately guiding the looper threads from said takeup member to the respective loopers, said second thread guiding means having a plurality of thread guiding surfaces arranged to provide greater frictional resistance to movement of said threads between said loopers and said takeup member than is provided by said thread guiding means to movement of threads between said tensioning means and said takeup member, and said loopers and guides being so arranged and said driving connections being so timed as to cause said takeup member to draw said looper threads over said thread guiding surfaces in directions away from the stitch when said looper threads are being drawn
  • Ann oyeredgensewingsmachine comprising a. reciprocablesneefdle, an under looper, an overedgeilooper, takeup meansyforhoperatinglon threads to saidloopers, driving connections for actuating said needle, said loopers. and said takeup means, firststhread guiding means for separatelyaguiding the looper threads from a supply into association with saidtakeup.

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  • Engineering & Computer Science (AREA)
  • Textile Engineering (AREA)
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Description

Jan. 10, 1956 E. scHou ETAL THREAD CONTROL MECHANISM FOR SEWING MACHINES 6 Sheets-Sheet 1 Filed NOV. 28, 1952 INVENTORS. EDGAR scnou BY SALVATORE LIPPERE ATTORNEY Jan. 10, 1956 E. SCHOIJ ET AL 7 M THREAD CONTROL MECHANISM FOR SEWING MACHINES Filed Nov. 28, 1952 6 Sheets-Sheet 3 43 FIG.3
/02 a I I r as y n [I 47;
INVENTORS.
F G. I l 69 7a EDGAR SOHO SAL VATORE L IPPERE ATTORNEY Jan. 10, 1956 ES. SCHOIJ ET AL 2,730,060
THREAD CONTROL MECHANISM FOR SEWING MACHINES Filed NOV. 28, 1952 6 Sheets-Sheet 4 IN VEN TORS. EDGAR SCHOIJ SALVATORE LIPPE RE BY ATTORNEY Jan 10, 19 E. SCHOIJ ETAL 2,730,060
THREAD CONTROL MECHANISM FOR SEWING MACHINES Filed NOV. 28, 1952 6 Sheets-Sheet 5 IN VEN TORS. EDGAR SGHOIJ SALVATORE LIPPERE ATTORNE rf Jan. 10, 1956 E. SCHOIJ ETAL 2,730,060
THREAD CONTROL MECHANISM FOR SEWING MACHINES Filed Nov. 28, 1952 e Sheets-Sheet 6 #9 48 l- :50 FIGJ5 4 5' 14a F /49 I53 1 150 67 I52 I54 /sa I52 I45 I47 I46 0 m N I57 A68 455 U 1 x40 40 D 9 1 IN VEN TORS. EDGAR SCHOIJ Y SALVATORE LIPPERE ATTORNEY THREAD CONTROL MECHANISM FOR SEWING MACHINES Edgar Schoij, Chicago, and Salvatore Lippere, Berwyn, 11]., assignors to Union Special Machine Company. Chicago, 111., a corporation of Illinois Application November 28, 1952, Serial No. 323,098
Claims. (Cl. 112-162) The present invention relates to sewing machines and more particularly to thread control in industrial sewing machines used in the production of three thread overedge stitches along the free edges of a plurality of superimposed pieces of work or along the free edge of a single piece of work.
In a machine of the above type, the thread handling requirements are to deliver the correct amounts of each thread at the correct times and under the correct tensions to the respective stitch forming instrumentalities. It is particularly important in the formation of certain types of stitches, such as the Federal Standard Stitch Type 504, that the tension of the threads be such that, at the formation of a stitch, they do not dig into or distort the work. In other words, it is desirable that a relatively relaxed stitch be formed. At the same time it is desirable that the threads be firmly drawn and uniformly positioned to pro vide a neat effect and to leave no loose loops of thread at the edge of the work.
Upon completion of a seaming operation, the usual practice is for the operator to chain out somewhat at the trailing end of the work so that the material may be taken up and the chain cut. In order to facilitate handling of the work, it is desirable that an elastic chain be produced. If an elastic chain is not produced, the operator must chain out an additional amount to compensate for the inelasticity of the chain or risk breaking one or more of the threads of the chain in pulling it toward the chain cutter.
In accordance with the above, a primary object of the invention has been .to provide improved thread control means for a threethread overedge sewing machine.
More particularly, it has been an object of the invention to provide improved thread control means for a three thread overedge sewing machine in which the correct amounts of each thread are delivered at the correct times and under the correct tensions to the respective stitch forming instrumentalities.
Another object of the invention has been to provide thread. control devices so constructed and coordinated as to be capable of producing a neat and firm, but relatively relaxed, three thread stitch which will not dig into or otherwise distort the edges of the work.
A still further object of the invention has been to pro vide coordinated thread control devices capable of producing a relatively elastic chain.
In accordance withthe invention, the foregoing objects have been achieved by providing an overedge sewing machine having a reciprocable needle, an under looper, an overedge looper, takeup mechanism for operating on threads to the needle and loopers, and driving connections for actuating the needle, the loopers and the takeup mechanism, with a first threadguiding means for separately guiding the looper threads from a supply into association with the takeup mechanism therefor, and second thread guiding means for separately guiding the looper threads from the takeup mechanism therefor to the respective loopers, the latter thread guiding means being constructed and arranged to provide substantial resistance to passage A United States Patent 0 of both looper threads between the takeup mechanism and the loopers and the driving connections beingarranged to cause the takeup mechanism to engage the looper threads as the loopers are operated away from the stitch forming point, whereby a substantial decrease in looper thread tension between the takeup mechanism and the looper is created during the interval in which the takeup mechanism is imparting takeup action to the looper threads.
Further in accordance with the invention, novel means are provided for drawing needle thread and looper threads from the supply, this means being arranged to draw from the supply the amount of under looper thread desired for each stitch before completely drawing from the supply the corresponding amounts of overedge looper thread and needle thread.
Also in accordance with the invention, the novel thread takeup means provided permits adjustment of the location of the purl on the edge of a stitch or seam by moving the thread eyelets but without adjustment of the thread tension means.
Other and further objects and features of the invention will appear from the following detailed description of an illustrative embodiment thereof shown in the appended drawings in which:
Fig. l is an end elevational view of an overedge sewing machine constructed in accordance with the invention, a portion of the machine frame being broken away to illustrate the thread handiing mechanism;
Fig. 2 is a view, partly in front elevation and partly in vertical section, of a portion of the overedge sewing machine of Fig. 1;
Fig. 3 is a plan view of a corresponding portion of the sewing machine of Fig. l, certain parts being broken away for clarity of illustration of other parts;
Fig. 4 is a detail view of one of the thread tension devices embodied in the machine;
Fig. 5 is an exploded view of the thread tension device shown in Fig. 4, showing the details of its component parts;
Fig. 6 is a perspective view of a thread guiding member embodied in the illustrative sewing machine;
Fig. 7 is a plan view of a portion of the sewing machine showing particularly the looper thread takeup eyelets and the under looper thread guiding eyelets;
Figs. 7a and 7b are end views of certain of the parts shown in plan in Fig. 7;
Fig. 8 is a detail view, in rear elevation, of the needle carrying arm and associated parts;
Fig. 9 is a detail view, in side elevation, of the needle arm, the looper thread takeup and cast-off means and related parts, the moving parts being shown at a time in the cycle of operation of the machine corresponding to the commencement of the needle downward stroke;
Fig. 10 is a detail view similar to Fig. 9 with the parts in the positions assumed when the looper thread cast-01f is about to push the under looper thread ed the looper thread takeup;
Fig. 11 is a perspective view of the looper thread castoti and the looper thread take-up showing the under looper thread as it is being forced off the takeup and the overedge looper thread engaged by the takeup;
Fig. 12 is a perspective view of the parts shown in Fig. 11 at a point in the cycle immediately after the under looper thread has been cast-off while the overedge looper thread is still engaged by the looper thread takeup;
Fig. 13 is a view, partly in front elevation and partly in section, of the parts shown in Fig. 12;
Fig. 14 is a perspective view of a thread stand arranged Referring now to the drawings, the overedge sewing machine illustrated is of the type disclosed in the copending patent application of Ned L. Wallenberg et al., Serial No. 196,104, filed November 17, 1950.
The machine is carried and largely enclosed by a frame (Figs. 1 and 2) which is of relatively low construction and is provided with a fiat bottom and a curved sloping top. This frame provides an enclosed chamber or housing portion 21 (Fig. 2) having a flat removable bottom plate 22 secured to the frame by screws or the like. Chamber 21 is shown only partially in the drawings. For a detailed description of the mechanisms contained therein reference may be had to the above mentioned Wallenberg et al. application. Chamber 21 is arranged to retain lubricant to a suitable level for the purpose of providing automatic lubrication of the major wear receiving parts of the mechanism, in the manner set forth in said pending application.
A vertical wall 23 at the left end of enclosed chamber 21 has an extension 24 at its lower end which partially encloses certain of the stitch forming and work feeding devices which must be provided exterior of the enclosed chamber 21. Further partial enclosure of the chamber above extension 24 is provided by a cloth plate 25 having downwardly extending apron portions which normally conceal the stitch forming and work feeding devices.
A main drive shaft 26 for the operating parts of the machine extends longitudinally of the frame, substantially. along a line about midway between the front and rear walls and midway between the planes of the bottom plate- 22 and the work supporting surface of cloth plate 25. Adjacent its left end, shaft 26 is supported by a pair of bearing sleeves 27 and 28 suitably mounted in the wall 23 of the frame. As shown, the bearing sleeve 28 is preferably mounted in a retainer 29 having a press fit in. an enlarged recess in the outer face of the wall 23.
A support member (Figs. 1, 2, 3 and 14) mounted on frame 20 is arranged to carry three thread tension devices 41, 42 and 43 for overedge looper thread 0, needle thread N, and under looper thread U, respectively. Tension device 41, as shown in Figs. 1, 2, 4 and 5, comprises a; screw 44having a knurled head 45 and a threaded stem portion 46. This screw passes through a hole in the top ofv support 40, through a bushing washer 47, through two mating tension discs 48 and 49 and through a tension spring 50. Threaded stem portion 46 engages a threaded hole in thecenter of a circular spring supporting plate 51 and is seated in an unthreaded recess or hole provided therefor in the-base 52 of support member 40. Plate 51 is provided with a slot 51A in one side thereof adapted to mate-with a pin 53.which is rigidly set in the base 52. Pin 53 prevents plate 51 from turning with screw 44, so that as the. screw is turned, by means of its knurled head 45, the plate 51 is raised or lowered, depending upon which way thescrew 6: is turned. Raising of the plate 51 compresses spring and hence forces the tension discs 48 and 49 under greater pressure into engagement with each other and, against the bushing washer 47. Similarly, lowering of:plate 51 decreases the tension of spring 50, reducing the force exerted. on tension. discs 48 and 49. The tension discs regulate the tension on the thread passing between them, and this thread tension is adjusted by turning head, 45.
Tension devices 42 and 43: may be identical with the device 41 described. Support member 40' performs an important. function with respect to each of the tension devices: in, that the side plate of member 40 acts as a shield covering. the tension. springs on the side facing the thread supply (Fig. 1), so that the thread cannot be caughtand broken in one of the. springs. The protection afforded thereby is of great significance at high sewing speeds. because, at such speeds, a substantial whipping action occurs between the thread supply and the tension discs.
The three threads 0'; N, and U come from their respective supply sources, which might be, for example, thread cones, and pass between the respective tension discs, as shown most clearly in Fig. 1 with respect to overedge looper thread 0. Inlet and outlet eyelets 54 and 55, respectively, are provided in member 40 for guiding each thread to and from a respective pair of tension discs, the thread being passed between the tension discs somewhat to one side of the associated screw 44.
After passing through tension device 42, needle thread N passes through an adjustable stationary guide eyelet 6% (Fig. 1), through a takeup 61 adjustably mounted on a trimmer bar 62 by means of a screw 63 cooperating with an elongated slot 64 in the takeup, thence successively through two eyelets in a stationary guide bar 65 extending from a plate 65a adjustably mounted on the machine frame by means of screws 66 cooperating with slots 67 (Fig. 1), and finally to the eye of a curved needle 68. Needle 68 is carried in a socket 68' on an arm 69 mounted on and oscillated by a rock shaft 70. Rock shaft 7%) is operated by suitable connect-ions (not shown in the drawings) with main shaft 26. Details of these connections, as well as other connections to the main shaft 26 to be set forth hereinafter, may be found in the aforementioned Wallenberg et al. applicatron.
The needle thread N tightens up and thread is drawn from the associated thread cone on the down stroke of the needle 68. The takeup 61 is normally carried as high on the. trimmer bar 62 as possible without causing threadto be drawn from the cone on the up stroke of the needle and of the trimmer bar. The principal purpose in providing the takeup 61 is to facilitate adjustment of needlethread N under various sewing conditions. Normally it only takes up a nominal amount of needle thread slack when the needle rises and delivers a nominal amount of needle thread when the needle'descendn'the operationof the trimmer bar being suitably coordinated with the. needle carrying arm and the takeup 61 being suitably adjusted on the trimmer bar to accomplish this. However, takeup 61 may be adjusted on trimmer bar 62 so that it will take and give more thread. In fact, takeup 61 may be adjusted to draw needle thread from theneedle thread cone should this prove desirable in meeting certain sewing conditions. Trimmer bar 62, which carries takeup 61, also carries a movable trimmer blade which is adapted to cooperate with a stationary trimmer blade (not shown) in shearing the edges of the work between successive advances, as is fully described in the said Wallenberg et al. application. Trimmer bar 62 is carried on a rock shaft 76, suitably connected by means (not shown) to main shaft 26. Rock shaft 76 and trim= rner bar 62 oscillate once upon each revolution of main shaft. The trimmer bar oscillations are timed together with those of needle 68, so that the trimmer bar descends when the needle descends and vicever'sa.
The overedge or upper looper thread 0' coming from, its' supply source passes through tension device 41 and then goes directly through aligned overedge looper thread takeup eyelets 8 0 and 80' and then to and through a; vertical tube 81 mounted on the machine frame and finally to the eye of an overedge looper 82 which is mounted: for reciprocation and oscillation on a looper shaft 83. Looper 82, is given a' combined r'e'ciprocatory and oscillatory movement, by suitable connections such" as shown in said Wallenberg et al. application, which imparts to the active end of the looper a spiral or'helical path. Overedge looper 82 is adapted to pass its thread through a loop of the under looper thread and then carry the loop of its own thread upwardly and over the edge of the work into the path of the curved needle 68 while the latter is in its uppermost position. Upon a subsequent oscillation of the needle 68,v its thread will be carried through the loop of the-overedge looper thread. Thread takeup eyelets 80. and 80. are formed, respectively, in parallel bars 84 and 84' adjustably mounted on a bracket 85 by means of screw 86 acting in elongated slot 87 and in a threaded hole through base or connecting sleeve 88 for the bars 84 and 84' (Fig. 6). Base 88 and bars 84 and 84 form a generally U-shaped bracket with aligned eyelet holes 80 and 80, as is shown most clearly in Fig. 6. Bracket 85 is adjustably mounted on the machine frame by suitable means shown in Fig. 7. A foot portion of the bracket is provided with an elongated slot 85a through which is passed a screw 85b for fastening the bracket to the frame. It will be apparent that the guide bars 84 and 84' may be adjusted both rotatably about the axis of the screw 86 and bodily with the latter in the slot 87 Also the bracket 85 may be adjusted bodily and even angularly on the frame to the extent permitted by slot 85a and screw 85b. This enables correct positioning of the eyelets 80 and 80 for all sewing conditions.
The under or lower looper thread U extends from its thread supply through tension device 43, through a stationary eyelet 95 (Figs. 2 and 3) adjustably mounted on the machine frame 20, through aligned under looper 5 thread takeup eyelets 96 and 96' (Figs. 1 and 13) and through spaced stationary eyelets 97 and 98 to an under looper 99. Eyelets 96 and 96' are formed in a bracket similar to the one shown in Fig. 6 and comprising apair of parallel bars 100 and 100 formed on a base 101 having a hole adapted to receive a screw 102 which cooperates with an elongated slot 103 in bracket 85. It is evident that bars 100 and 100' are rotatably and laterally adjustable within bracket 85 and may be adjusted with the latter in the same manner as bars 84 and 84'. Eyelets 97 and 98 are formed in end projections of a thread supporting member 104 rigidly mounted on an adjustable guide member 105, as shown in Fig. 7. Guide member 105 together with a second adjustable guide member 106 maintains feed bars 107 and 108 in place.
Guide 106 is mounted on the machine frame by screws 109 and 110 which act in an elongated slot 111 in a laterally extending arm of guide 106, as best shown in Fig. 7a. Provision of elongated slot 111 permits lateral adjustment of guide 106. Guide 105 is mounted on the machine frame by a screw 112 acting in an elongated slot 113 in guide 105, as best shown in Fig. 7b. Provision of elongated slot 113 permits lateral adjustment of guide 105. It is evident that lateral adjustment of guide 105 will also provide a slight lateral adjustment of eyelets 97 'and 98.
Under looper 99, which carries thread U, is mounted for reciprocation on a rod 110 actuated from main shaft 26 by suitable connections, not shown in the drawings but disclosed in said Wallenberg et a1. application. Looper 99 executes a simple reciprocatory movement along a straight line. Rod 110 is disposed at an acute angle, preferably between 20 and 30 to the horizontal, and serves upon reciprocation to carry the thread-carrying eye of the under looper 99 from a position at the left of the path of the needle and some distance below the cloth plate to a point at the right of the path of the needle and substantially in the plane of the cloth plate 25 (Fig. 2). In such movement, the looper 99 is adapted to pass its thread through the loop of needle thread which is, at this time, presented below the cloth plate.
Both looper threads 0 and U are acted upon by a takeup member 115 which is mounted on and oscillated by the needle bar rock shaft 70. Takeup member 115, which is best illustrated in Figs. 8 through 13, comprises an arm 116 clamped to the shaft 70, adjacent the needle carrying arm, and a bifurcated member 117 fastened to arm 116 by means of a screw 118. The branches of member 117 are divided into straight takeup portions 119 and 119', which extend radially in relation to shaft 70, and curved or bent reentrant portions 120 and 120' which provide cast-off edges at the lower ends of portions 119 and 119 and surfaces to receive the cast-off thread. Portions 119 and 119 of takeup member 115 are arranged to move along an arcuate path between eyelet bars 84 and 84' and between eyelet bars 100 and 100',
which, it will be remembered, are adjustably mounted on bracket 85. A castoif member 125 is adjustably mounted on bracket by means of a screw 126 acting in an elongated slot 127 in a rearward extension of member 125. This extension is clamped within a slotted downward extension 128 of bracket 85, the inner branch of which is threaded to receive the screw 126. Cast-01f member 125 extends upwardly and outwardly to act between the forked takeup portions 119 and 119' of arm 117.
in the ascending portion of its oscillatory cycle, takeup member engages under looper thread U between eyelets 96 and 96 and carries the same on takeup portions 119 and 119 (Fig. 11) until thread U is urged off of the same by the lower edge of cast-off member 125. Cast-off member 125 casts thread U off the lower edges of takeup portions 119 and 119 and into the curved portions and 120' as the takeup reaches about the position indicated in Figs. 10 and 12. It will be observed that the arrangement of cast-off member prevents interference with overedge looper thread 0 by under looper thread U. As takeup member 115 rises, the overedge looper thread 0, which is normally resting on the upper edges of cast-off member 125 (Fig. 2) is engaged by portions 119 and 119 (Figs. 11 and 12) and is carried along or somewhat above the upper edge of cast-01f member 125 and away from eyelets 80 and 80 (Fig. 13). The extent of the takeup action on the thread 0 at different points in the cycle may be controlled in part by the member 125.
it should be observed that the overedge looper thread eyelet bars 84 and 84, the under looper thread eyelet bars 100 and 100, and the cast-oif member 125 are individually adjustable relative to their common supporting bracket 85. Furthermore, these thread controlling elements are adjustable as a unit because, as has been noted hereinbefore, bracket 85 is adjustable relative to the machine frame.
A complete stitching cycle of the thread control and stitching instrumentalities will. now be described. Looper motions will be considered forward when a looper enters a thread triangle or loop and backward when a looper sheds thread. Starting with needle 68 in its uppermost position and ready to begin its descent, the overedge looper 82 just reaches its uppermost and foremost position as the needle starts to descend, so that the needle will enter a thread triangle formed by overedge looper 82 as the latter starts its return from this position. The under looper 99 has started its backward motion and sheds the needle loop seized thereby in the preceding cycle. The looper thread takeup member 115, being fixed to the needle bar rock shaft 70, starts its upward movement when needle 68 commences its downward travel. At substantially the same time, needle thread takeup 61, which is mounted on trimmer bar 62, starts its downward motion. Just after the needle enters the overedge looper thread triangle but before it enters the Work, the looper thread takeup 115 engages the under looper thread U. Under looper thread U starts to be drawn from its supply while it is still around the overedge looper 82. Most of the thread is drawn as under looper thread U approaches and comes off the point of overedge looper 82, although a little more thread is drawn as the under looper thread is pulled to the edge of the Work. Looper thread takeup 115 engages the overedge looper thread 0 as the overedge looper 82 moves away from the line of stitch formation. The under looper thread U is cast off from the overedge looper 82, pulled down to the stitch and then is cast off takeup portions 119 and 119'. Following this step, the under looper 99 starts forward to enter the needle thread loop and the overedge looper tive. supply. cones. stops as the needlelfiS reaches the. bottom of. its. stroke; The-under looper 99' enters the needle thread. loop as. the needle 68 begins to rise and the looper thread takeup 1 15. is starting its backward motion. When needle. 68 is. approximately midway in its ascent, the overedge looper 82 enters the lower looper thread triangle, as shown in Fig; 2. The various stitch forming elements continueon to their original positions preparatory to commencement of another stitch forming cycle. Feeding of the work, which may be performed as described in the said Wallenberg et al. application, takes place when the needleis out of the Work.
It will be observed that thepath. of overedge looper thread from tension. device 41. to the eye of overedge looper 82 may conveniently be divided into two portions, one extending from tension device 43 to-talzeup-mernber 115 .and the other from takeup member 115 to the overedge looper 82. A substantial frictional resistance to thread passage is provided in the latter portion because ofthe thread guiding surfaces provided therein and particularly because of thenumber, extent, and angular disposition ofthe. surfaces encountered. More specifically, during a portion of the ascent of takeup member 115, thread 0 is drawn from the associated supply cone or bobbin, through v tension device 41, eyelet 55 and eyelet 80 to takeup member 115. The thread controlling means from the takeup to the stitch are so arranged for the overedge looper thread that at each thread contacting surface thereof when thread is being drawn from the supply, i. e., as the needle is approaching the bottom of its stroke, the tension is reduced on the side closest the.
stitch by the amount of friction created at each of said thread contacting surfaces. This is accomplished by arranging such thread control so that at each of the contacting surfaces thereof the thread moves relative to the thread contacting surface away from the stitch. As a result, the tension in thread 0 decreases from takeup member 115 to overedge looper 82, providing a relatively low tension at the stitch whereby the overedge looper thread 0 is laid onto the material in a relaxed manner. The overedge looper thread tension at the stitch is preferably made about one third of the overedge looper thread tension adjacent the takeup member. Decrease in thread tension at overedge looper 82 is also aided by the fact that over-edge looper 82 is moving away from the stitch point. when takeup member 115 contacts Because of the drop in tension between takeup member 115 and the overedge looper 82, a relatively high tension may he provided at tension discs 48 and 49 of tension device 41, so that the effect of thread variation is reduced. For example, if a tension at the stitch of one ounce is required and the tension at the takeup H5 is normally ounces, then a variation of one ounce at the tension discs 43 and 49'means only a variation of of an ounce at the stitch. However, if the tension at the tension discs is'the' same as the tension at the stitch, then a variation of one ounce at the tension discs will cause azvari'ationof one ounce at the point of stitch formation. Similarly, if the tension at the stitch is higher than at the tension discs, then a variation at the tension discs will result in a correspondingly higher variation at the stitch. A desirable effect of the reduction in thread tension atthe stitch and the permissible increased. tension at the tension discs 48 and 49 is the formation of more uniform stitches.
A decreasein tension of thread 0 from takeup member 115. to1 overedge looper 82 reduces thread breakage and permits the use of poorer grade threads. If the tension were to increase rather than decrease, the tension atthe tension discs would have to be substantially lower than is. desirablev inorder. to preventexcessive; threadtbreakage".
between thetakeup and overedge-looper.
It. will be observed that the tension. in under looper" thread U decreases between; takeup. member and; underlooper 9.9 because of' the relatively high frictional; resistanceof this: portion of the. lower looper'threadpath andbecause v of the direction of, thread movementacross. each threadcontactingsurface. Thisaresult is aided. also;
bythe direction of. movement. of the looper duringthe:
takeup actiorrof. member 115. Thetension in the; lowcr thread at the stitchdoes-not have:as significant anreifect; on the stitch as isin the. case of the overedge looperthread' 0 because the. stitch tongue". 138 onthe throat. plate 159 (Fig. l) helps keep the thread-.from;diggi ng.- intothe material. Since theneedle thread doesnotcome: over the edge of the materiahitisnottroublesomeinthis; respect. the needle thread N. at the stitch. because. of difficulty; in; pulling up theneedlethread. This tension should be-.-the-; highest in the system and the tension in'the. thread be+ tween thewtension. discsof device: 42=andthe needle68 should be maintainedas closeto the maximum. aspossible to reduce effects of thread variation; a
it should-be notedthat under looper threadU isrcomr pletely drawn. fronrits cone'or: bobbin'prior to the complete drawing. of. needlethreadN and overedge looper thread. 0. from theirrespective cones or'bobbins- Draw.- ingof. the needle thread.N=and the overedge looper thread; 0 does not: start untildrawing of. the-under looper; thread is almost. complete, resulting in formationv of a. more; elastic chain. When the needle thread N and overedge thread. 0 are tightened up as the needle 681gpes to the: bcttornof its stroke and. the under looper thread-U isnct tight,v the. stitch is not distorted. to any. extent because: the needle thread. N. is being pulled. up. to the material: and does notpulltheunderlooper thread U: away from the edge. The overedge looper thread 0 is around the: needle 63 and cannot. pull the under looper threadU oven the edge because. of thesnubbing action of the needle 68, and because the under looper thread U is held to some extent by the needle thread N. When chainingthe under looperthread U tightens up, when. it is around the overedge looper. Prior to this time theneedle threadN, has, slipped. off the under looper and. isrelatively slack. The tight. under looper thread. U. coming off. the. overedge looper is pulled quickly tov the. edge of the throat", plate stitch tongue. and the needle thread loop is located: at the edge of the stitch tongue. Thisaction causes-the needlethread to form in the chain in. an S-shape on the under. surface of the stitch tongue so that sufficient needle thread; is pulled into the chain to make: it elastic. When sewing the tightening of the under looper thread U when the under thread is still. around. the overedge looper tends to,- pull" down the previously pulled. needle thread loop,.butsuch. pulling down is corrected. when the needle: descendsto. the bottom of its. stroke. The fact that the. under looper U is slack when the needle thread- N is being pulled. up to its final position. permits a minimum amount of needle thread tension to be used for pulling upthe needle thread. An elastic chain facilitates feeding the chainv out when no material is being sewn and also facilitates pulliug the material out to cut the chain, which reduces thread breakage.
Referring now to Figs. 14 and 15, the thread stand illustrated has been found well suited. for supplying the three threads to the overedge sewing machine. The thread stand comprises an upright supporting rod 140 which is mounted at its lower end, in suitable socket 141 provided in a table top 1.42. An adjustable clamp 143 is mounted on the upper end of a rod 1.40.. A hori zontal arm or rod 144 is supported in clamp 143'. Adjacent, either end; and at the center of rod. 144: are mounted. three upright supporting rods 145, 146 and 1.47, respec: tively, each terminating in an inverted L-shaped head at the upper end thereof. At the free end. of each supporting it is desirableto provide a maximumtension; in
rod there is provided an S-shaped hook 148 adapted to fit into a hole 149 of the associated rod and into a hole 150 of a respective cone supporting rod 151. Each of rods 151 is provided adjacent each extremity thereof with a collar 152. secured to rod 151 by set screws 153. Slidably mounted on each rod 151 between the limits provided by collars 152 is a wood block 154 having a generally frustro-conical shape. Thread cones O, N, and U which supply, respectively, threads 0, N, and U, may be placed upside down on the respective blocks 154. By jamming the thread cones on the respective blocks and against the upper collars 152, the cones are frictionally held to the blocks. When it is desired to remove a cone from the associated block, the cone may be pulled downwardly and off the block, lower collar 152 retaining the block on the rod 151. A C-shaped horizontal guide member 155 is mounted in rod 144 and provided with thread guiding holes 156, 157 and 158 each disposed below a respective thread cone and adapted to receive and guide threads 0, N, and U respectively.
While the invention has been described in a specific embodiment thereof and in a specific use, it should be understood that the invention is not limited thereto for obvious modifications thereof will occur to those skilled in the art without departing from the spirit and scope of the invention as set forth in the appended claims:
What is claimed is:
1. In an overedge sewing machine having a main drive shaft stitch forming means including a needle, an overedge looper and an under looper, and connections from said shaft for operating said stitch forming means in coordination to form overedge stitches, the combination of thread controlling devices for controlling the delivery of threads from sources of supply to said stitch forming means, said devices including a plurality of thread guiding means for each of the threads delivered to the needle, the overedge looper and the under looper, a plurality of thread takeup members arranged to act upon the several threads in the course of their delivery to said stitch forming means, and connections from said shaft for operating said takeup members in such timed relation as to completely draw the thread delivered to said under looper from its source of supply before the threads delivered to said needle and said overedge looper are completely drawn from their sources of supply, said takeup members being arranged to draw all of said threads from their sources of supply during the latter part of the downward movement of the neddle.
2. In an overedge sewing machine having a main drive shaft stitch forming means includin a needle, an overedge looper and an under looper, and connections from said shaft for operating said stitch forming means in coordination to form overedge stitches, the combination of thread controlling devices for controlling the delivery of threads from sources of supply to said stitch forming means, said devices including a plurality of thread guiding means for each of the threads delivered to the needle, the overedge looper and the under looper'and a plurality of thread takeup members arranged to act upon the several threads in the course of their delivery to said stitch forming means, connections from said shaft for operating said take up members, and thread tensioning means acting upon the several threads between their sourses of supply and said takeup members, said devices and said means for operating said stitch forming means and said take up members being constructed and arranged to exert the primary takeup action on the overedge looper thread as said looper is moving away from the point of stitch formation and as the path of said thread is being shortened from the point of stitch formation to the nearest guide for said thread, so ,as to impart a substantially lower tension to the thread delivered to said overedge looper at the point of stitch formation than adjacent the associated takeup member. i
3. An overedge sewing machine comprising a main shaft, a reciprocable needle, an under looper, an overedge looper, means for drawing needle thread and looper threads from a supply, said means serving to draw off all of said threads from their sources of supply during the latter part of the downward movement of the needle and being arranged to completely draw from the supply the amount of under looper thread desired. for each stitch before completely drawing from the supply the corresponding amounts of overedge looper thread and needle thread, said means including a takeup member for operating on both of the looper threads, and driving connections from said shaft for actuating said needle, said loopers and said takeup member to effect said timing of their actions.
4. An overedge sewing machine comprising a reciprocable needle, an under looper, an overedge looper, means for drawing needle thread and looper threads from a supply, said means serving to draw thread from the supply for said needle and said loopers as the needle is descending and being arranged to draw from the supply the amount of under looper thread desired for each stitch before drawing from the supply the corresponding amounts of overedge looper thread and needle thread, and said means including a needle thread takeup element arranged to cooperate with said needle in drawing thread from said supply, a takeup member having a takeup portion for engaging and drawing from said supply said under looper thread and said overedge looper thread and having a cast-off thread receiving portion, said takeup member being arranged to draw most of said under looper thread from said supply before drawing said overedge looper thread from said supply and to completely draw said under looper thread from said supply before completely drawing said overedge looper thread from said supply, a cast-off member arranged to cooperate with said takeup portion to cause said under looper thread to be disengaged from said takeup portion and engaged by said cast-off thread receiving portion as said takeup member is moving in a direction to takeup thread, and driving connections for actuating said needle, said loopers, said takeup element and said takeup member in coordinated relation to effect said timing of their actions.
5, An overedge sewing machine comprising a reciprocable needle, an under looper, an overedge looper, means for drawing needle thread and looper threads from a supply, said means serving to draw thread from the supply for said needle and said loopers as the needle is descending and being arranged to draw from the supply the amount of under looper threaddesired for each stitch before drawing from the supply the corresponding amounts of overedge looper thread and needle thread, and said means including a needle thread takeup element arranged to cooperate with said needle in drawing thread from said supply, a takeup member having a takeup por: tion for engaigng and drawing from said supply said under looper thread and said overedge looper thread and having a cast-01f thread receiving portion, said takeup member being arranged to draw most of said under looper thread from said supply before drawing said overedge looper thread from said supply and to completely draw said under looper thread from said supply before completely drawing said overedge looper thread from said supply, a cast-off member arranged to cooperate with said takeup portion to cause said under looper thread to be disengaged from said takeup portion and engaged by said cast-off thread receiving portion as said take up member is moving in a direction to take up thread, and driving connections for actuating said needle, said loopers, said takeup element, and said takeup member in coordinatedrelation to effect said timing of their actions, said driving" connections including a rock shaft for'reciprocating said needle and said takeup member. f
6. An overedge sewing machine comprising a recipro cable needle, an under looper, an overedge looper,means fondrawingneedle: threadand loopenthreads from .a supplyasaidsmeansaserving: to ,drawthread; from, the supply.
forzsaid needletand said loopers as the needle .is descend ing andx-beingarranged ttocompletely: draw from the supply: the; amount of under looper. thread desiredqfor eachstitchbeforecompletely drawing from the supply, the .co,r-. responding. amounts of-overedge looper thread and needle thread, .and said means .includingatakeup mechanism for. operating;on-,the I looper; threads, driving connections for;
actuatingsaidtneedle, said loopersandsaid takeup mecha-.
nism,-., first: thread guidingmeansifor separately guiding thezlooperythreads fromthezsupply intoassociation with saidztakeup; mechanism, and secondthread guiding means. for separately guiding the;looper threads from said takeupmechanism to the respective loopers, said latter tthread:
guiding-;mea-nsz being constructed and arranged to provide substantialiresistance --to passage, of overedge looper thread between said;.takeup.mechanism and the overedge looper. andbeing; arranged to deliver thread to the overedge looper-alongsuch agpath that said looper yields thread as saidtakeup mechanism, is imparting its primary takeup action to the overedge looper thread, and said driving connections being so timed as to cause said takeup mechanism, to; engage the overedge looper thread as said overedge looper is operated awayfrom the stitch forming point whereby a substantially lower tension is imparted tothe-thread deliveredto theoveredge looper at the point of stitchzformation than is, imparted thereto adjacent said takeup mechanism during the interval inwhich said takeupmechanism is-imparting takeup action to said overedge looper thread.
7.v An overedge sewing machine comprising a reciproeableneedle,anunderlooper, an overedge looper, atake up mechanism for operating on threads to said loopers, driving connections-for actuating said needle, said loopers and. said, takeup mechanism, first thread guiding means for separately guiding the looper threads from a supplyinto. association with said takeup mechanism, and second thread, guiding means for separately guiding the looper threads from said takeup. mechanism to the respective loopers, said. latter thread guiding means having a plurality of thread contacting surfaces and being constructed and arranged to provide substantial resistance to passage of. overedge looper thread, between said takeup mechanism and the overedge looper and being arranged to deliver thread to theoveredge looper along such a path that saidlooper yields, thread as said takeup mechanism is imparting its primary: takeup action to the overedge looper, thread, and said driving connections being so timed. as to cause said takeup mechanism to engage theoveredge looper tthread and to, draw the same over the associated thread contactingsurfaces of said second thread guiding means in directions. away from the stitch when said overedge looper thread is being drawn from its 1 29 31 h tionship of the several parts being such that. the: overedge looper thread tension adjacent said takeup mechanism .is approximately three times the tension therein at the stitch.
8. An overedge sewing machine comprising a reciprocable needle, an under looper, an. overedgelooper, a takeup member for operating on threads to said loopers, drivingconnections; for actuating: said needle, said loopers and said takeup member, first thread guiding means for separately guiding the looper threads from a supply into association with said takeup member, and second thread guiding means for separately guiding the looper threads from said takeup member to the respective loopers, said latter thread guiding means being constructed and ar-. ranged. to provide; substantial resistance to passage ofthe looper threads between said takeup member and the re-. spective loopers and being arranged to, deliver threads to said, loopers along such paths that said loopers yield thread as said takeup member is, imparting its primary takeup action, to the looper threads, and said drivingconnections being so timed as to, cause said takeup member 12 to engage;v the overedge; looper threadassaid overedge looper-is operated away. fromthe. stitch forming point whereby asubstantial decrease, in overedgelooper thread tension between saidtakeupmember andsaidoveredge looper is provided during the interval in which said take:
up member is imparting takeup action to saidioveredgev looper thread.
9. An overedge sewingmachine comprising a recipro-v cable needle, an under looper, an overedgelooper, aitaker. up member for operatingon threads to said loopers, driv-, ing connections for actuating said needle, said loopersand said takeup member, first thread guiding means fonsepa; rately'guiding the looper. threads from supply. means into association with said takeup member, and second thread. guiding means for separately guiding the looper. threads from. said takeupmernber to the. respective loopers, saidj latter thread guiding means. comprising a. plu'raliti of thread guiding surfaces arranged. to carry thev overedge looper thread and to guidethe same along. a path having portions disposed at sharp angles relativeto "each other. between said takeup member and said overedge. looper thereby to provide substantial resistance to passage of overedge looper thread between said takeup memberand the overedge looper, said second thread guidingmeans being arranged also todeliver thread tofthe overedge looper along such a path. that said looper yieldsthread as said takeup member is imparting its primary takeup action to the overedge looper thread, and said driving connections being so timed as to cause said takeup member to engagethe overedge looper thread and to drawthe same over said thread guiding surfaces in directions away from the stitch. when said overedgelooper thread is being drawnfrom said supply whereby the tension in the overedge looper thread. at the stitch is substantially-lower than the tension therein adjacent said takeup memberwhen said overedge looper thread isbeing drawn from said supply.
10. An overedge sewing-machine. comprising arecipro: cable needle, an under looper, an overedge looper, a takeup member for operating on threads to said loopers, saidtakeup member having a takeup portion for engaging said looper threads and for drawing the same from a supply and having a cast-off thread'receiving portion, a cast-off member so disposed relative to said takeup member as to disengage the under looper thread from said takeup portion as said member is moving in its thread take up direction and causing the same to be engaged by said cast-off thread receiving portion after the amountof under looper thread desired for a stitch has been drawn from the supply, driving connections for actuating said needle, said loopers and said takeup member, first thread guiding means for separately guiding the looper threads from said supply into association with said takeup member, and second thread guiding means for separately. guiding the looper threads from said takeup member to the, respective loopers, said latter thread guiding means being provided with a plurality of thread guiding surfaces constructed and arranged to, provide substantial resistance to passage of overedge looper thread between said takeup, member and the overedge looper, and said driving. con nections being so timed as to cause said takeup. member to engage the overedge looper thread and to draw the same over said thread guiding surfaces in directions away from the stitch when said overedge looper thread is being drawn from said supply whereby the tension in the over edge looper thread at the stitch is substantially lower than the tension therein adjacent said takeup member when said overedge looper thread is being drawn from said 13 member so disposed relative to said takeup member as to disengage the under looper thread from said takeup portion as said member is moving in its thread take up direction and causing the same to be engaged by said cast-off thread receiving portion after the amount of under looper thread desired for a stitch has been drawn from the supply, driving connections for actuating said needle, said loopers and said takeup member, first thread guiding means for separately guiding the looper threads from said supply into association with said takeup member, and second thread guiding means for separately guiding the looper threads from said takeup member to the respective loopers, said latter thread guiding means comprising a plurality of thread guiding surfaces arranged to carry the overedge looper thread and to guide the same along a path having portions disposed at sharp angles relative to each other between said takeup member and said over edge looper thereby to provide substantial resistance to passage of overedge looper thread between said takeup member and the overedge looper, and said driving connections being so timed as to cause said takeup member to engage the overedge looper thread and to draw the same over said thread guiding surfaces in directions away from the stitch when said overedge looper thread is being drawn from said supply whereby the tension in the overedge looper thread at the stitch is substantially lower than the tension therein adjacent said takeup member when said overedge looper thread is being drawn from said supply.
12. An overedge sewing machine comprising a reciprocable needle, an under looper, an overedge looper, a takeup member for operating on threads to said loopers, driving connections for actuating said needle, said loopers and said takeup member, first thread guiding means for separately guiding the looper threads from a supply into association with said takeup member, said first thread guiding means including a first takeup eyelet for the overedge looper thread and a second takeup eyelet for the under looper thread, said takeup member being arranged to engage said looper threads adjacent the respective takeup eyelets and having a generally straight takeup portion for engaging the looper threads and drawing the same from a supply and having a re-entrant cast-off thread receiving portion, a stationary cast-off member disposed adjacent the respective takeup eyelets and so arranged relative to said takeup member as to cause disengagement of the under looper thread from said takeup portion as said member is moving in its thread take up direction and to cause the same to be engaged by said cast-off thread receiving portion after the amount of under looper thread desired for a stitch has been drawn from the supply, and second thread guiding means for separately guiding the looper threads from said takeup member to the respective loopers, said second thread guiding means including third and fourth takeup eyelets for carrying said overedge looper thread and said under looper thread, respectively, and being spaced, respectively, from said first and second takeup eyelets, said takeup member and said cast-01f member being accommodated between said first and third takeup eyelets and between said second and fourth takeup eyelets, said second thread guiding means being provided with a plurality of thread guiding surfaces constructed and arranged to provide substantial resistance to passage of overedge looper thread between said takeup member and the overedge looper, and said driving connections being so timed as to cause said takeup member to engage the overedge looper thread and to draw the same over said thread guiding surfaces in directions away from the stitch when said overedge looper thread isbeing drawn from said supply whereby the tension in the overedge looper thread at the stitch is substantially lower than the tension therein adjacent said third takeup eyelet when said takeup member is imparting takeup action to said overedge looper thread.
13. An overedge sewing machine comprising a recipro- 14 cable needle, an under looper, an overedge looper, a takeup member for operating on threads to said loopers, driving connections for actuating said needle, said loopers and said takeup member, first thread guiding means for separately guiding the looper threads from a supply into association with said takeup member, said first thread guiding means including a first takeup eyelet for the overedge looper thread and a second takeup eyelet for the under looper thread, said takeup member being arranged to engage said looper threads adjacent the respective takeup eyelets and having a generally straight takeup portion for engaging the looper threads and drawing the same from a supply and having a re-entrant cast-off thread receiving portion, a stationary cast-off member disposed adjacent the respective takeup eyelets and being so arranged relative to said takeup member as to cause disengagement of the under looper thread from said takeup portion and to cause the same to be engaged by said cast-oif thread receiving portion after the amount of under looper thread desired for a stitch has been drawn from the supply, and second thread guiding means for separately guiding the looper threads from said take-up member to the respective loopers, said second thread guiding means including third and fourth takeup eyelets for carrying said overedge looper thread and said under looper thread, respectively, and being spaced, respectively, from said first and second takeup eyelets, said takeup member and said cast-off member being accommodated between said first and third takeup eyelets and between said second and fourth takeup eyelets, said second thread guiding means comprising a plurality of thread guiding surfaces for said overedge looper thread including said third takeup eyelet and a thread carrying tube located between said third eyelet and said overedge looper and being angularly disposed relative to the path therebetween, said third eyelet and said tube providing a relatively high resistance path for passage of overedge looper thread between said takeup member and the overedge looper, and said driving connections being so timed as to cause said takeup portion to engage the overedge looper thread and to draw the same over said thread guiding surfaces in directions away from the stitch when said overedge looper thread is being drawn from said supply whereby the tension in the overedge looper thread at the stitch is substantially lower than the tension therein adjacent said third takeup eyelet when said takeup member is imparting takeup action to said overedge looper thread.
14. An overedge sewing machine comprising a reciprocable needle, an under looper, an overedge looper, takeup means for operating on threads to said loopers, driving connections for actuating said needle, said loopers and said takeup means, first thread guiding means for separately guiding the looper threads from a supply into association with said takeup member, adjustable thread tensioning means associated with said first thread guiding means for tensioning the looper threads between the supply and said takeup member, and second thread guiding means for separately guiding the looper threads from said takeup member to the respective loopers, said second thread guiding means having a plurality of thread guiding surfaces arranged to provide greater frictional resistance to movement of said threads between said loopers and said takeup member than is provided by said thread guiding means to movement of threads between said tensioning means and said takeup member, and said loopers and guides being so arranged and said driving connections being so timed as to cause said takeup member to draw said looper threads over said thread guiding surfaces in directions away from the stitch when said looper threads are being drawn from the supply whereby the tensions in said looper threads at the stitch are substantially lower than the tensions therein adjacent the takeup member when said looper threads are being drawn from the supply.
15: Ann oyeredgensewingsmachine comprising a. reciprocablesneefdle, an under looper, an overedgeilooper, takeup meansyforhoperatinglon threads to saidloopers, driving connections for actuating said needle, said loopers. and said takeup means, firststhread guiding means for separatelyaguiding the looper threads from a supply into association with saidtakeup. member, adjustable thread tensioningmeans associated with saidvfirst thread guiding means for .tensioning the loopervthreads between the sup-' ply and said, takeup member, and second thread guiding meanslfor separately guiding the looper threads from said takeup vmeanssto the respective loopers, saidsecond thread guiding means comprising a plurality of thread contact.- ing surfaces, arranged toprovide greater frictional resistance to movement of said threadsbetween said loopers and said takeup, member than'is provided by saidtthread guiding means 'to movement ofthreads between said 16 andrguidesrb eing so arranged'and said driving connections being so timed that said overedge looper thread is drawn over the associated thread contactingsurfaces' of said second thread guiding means in directions away from the stitch when said overedge looper thread is being drawn from said supply whereby the overedge looper 1988,051 Rubel Jan. 15, 1935 2,054,493: Ebert Sept. 15, 1936 2,157,373 was May9f, 1939 2,265,678 Summers et a1 Dec. 9,l
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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2871486A (en) * 1955-06-06 1959-02-03 Cluett Peabody & Co Inc Non-shrinking seam and method of making
US2973731A (en) * 1955-05-31 1961-03-07 Man Sew Corp Compound stitching device
US3101686A (en) * 1959-01-19 1963-08-27 Union Special Machine Co Machine for producing safety stitch

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1988051A (en) * 1932-04-05 1935-01-15 Union Special Machine Co Thread controller for sewing machines
US2054498A (en) * 1933-03-08 1936-09-15 Ebert Fritz Overcasting sewing machine
US2157373A (en) * 1936-12-29 1939-05-09 Willcox & Gibbs Sewing Machine Thread handling device for sewing machines
US2265678A (en) * 1938-11-19 1941-12-09 Willcox & Gibbs Sewing Machine Sewing machine

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1988051A (en) * 1932-04-05 1935-01-15 Union Special Machine Co Thread controller for sewing machines
US2054498A (en) * 1933-03-08 1936-09-15 Ebert Fritz Overcasting sewing machine
US2157373A (en) * 1936-12-29 1939-05-09 Willcox & Gibbs Sewing Machine Thread handling device for sewing machines
US2265678A (en) * 1938-11-19 1941-12-09 Willcox & Gibbs Sewing Machine Sewing machine

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2973731A (en) * 1955-05-31 1961-03-07 Man Sew Corp Compound stitching device
US2871486A (en) * 1955-06-06 1959-02-03 Cluett Peabody & Co Inc Non-shrinking seam and method of making
US3101686A (en) * 1959-01-19 1963-08-27 Union Special Machine Co Machine for producing safety stitch

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