US2718859A - Looper spreader mechanisms for sewing machines - Google Patents

Description

Sept. 27, 1955 F. F. ZElER LOOPER SPREADER MECHANISMS FOR SEWING MACHINES Filed Oct. 17, 1951 2 Sheets-Sheet l SQ IN V EN TOR;

ATTORNEY F. F. ZEIER Sept. 27, 1955 LOOPER SPREADER MECHANISMS FOR SEWING MACHINES 2 Sheets-Sheet 2 Filed Oct.

1 ix INVENTOR.

fiedericfi cf eier A T TORNE Y M s Eon SEWING The present invention relates to chain-stitch sewing machines andhasfora primary object to provide an improved thread-lobp forming mechanism, particularly for the looper-thread, of such machines. 1 t

More specifically, the present invention has for its ob ject to provide a-positive thread-detaining means for seizing and holding the thread, andparticularly the looper thread, of a chain-stitch sewing machine to insure proper formation of a thread triangle and enchaining of the looper-thread with the needle thread; i"

Having in mind these and other objects that will'be evident from an understanding of this disclosure, apresently preferred embodiment of this invention is' hereinafter set forth in such detail as to enable those skilled in the art to readily understand the function, operation, construction and advantages of it, when read in conjunction with the accompanying drawings, in which:

Fig. 1 is a front end elevation of a two-needle, twothread, chain-stitch, feed-off-the-arm sewing machine, with the work-arm shown in vertical longitudinal section and including a thread detaining mechanism constructed in accordance with the present invention:

Fig. 2 is a horizontal section on an enlarged scale taken substantially on the line 2 2"of Fig. l, but'having the feed mechanism of the machine omitted to more clearly illustrate the inventionw r r Figs. 3 and 4 are fragmentary views on an enlarged scale of Fig, 2, showing the left-hand portion of the workarm as seen in Fig. 2 and showing the mechanisms in different positions. I

Fig. 5 is a vertical section taken substantially on the line 5-5 ofFig. 3. p

Figs. 6 and 7 are detail views in perspective of two of the component elements of the thread-detaining mechamsm.

The machine that has been selected for purposes of illustrating the preferred embodiment of the present invention is a two needle, two-third, chain-stitch, feed-olfthe-arm sewing machine substantially as disclosed in. my co-pending U. S. patent'application, Serial No. 15,805, filed March 19, 1948, now Patent No. 2,623,484, dated December 30, 1952, to which reference may be made for a more complete understanding ofthe details of the illustrated machine. The following description relates more particularly to those elements'ofthe machine that are necessary to completely understand the present invention.

The sewing machine illustrated in the drawings includes a frame 10 having a vertically depending arm 11 carrying a horizontal work-supporting cylinder-bed or arm 12 which is of very small diameter to permit small diameter articles to be sewed thereon. The work-arm 12 is so disposed that the free end thereof underlies a head 13 in which are journaled a needle-bar 141 and ajpresser-bar 15 carrying, respectively, a pair of needles 16 and a resser-foot 17. t

Mounted within the work-arm 12 is a feed-dog 18 that vance the work past the stitching mechanism. The feeddog 18 is carried upon one end of a. feed-bar 19 extending longitudinally of the Work-arm. The feed-bar 19 is longitudinally slidable and crosswise pivotally mounted on bearing blocks 20 embracing an eccentric pin 21 which provides for vertical adjustment of the blocks. Feed-advance and -return movements are imparted to the feed-bar 19 by a rock-lever 22 and feed-lift movements by a link 23. The rock-lever 22 and link 23 are secured to the feed-bar 19 in appropriate driving relation, and they receive their motions from a driven shaft 24 journaled horizontally in the frame 10 and having an end thereof projecting into the upper portion of the depending arm 11. The rock-lever 22 is driven by the shaft24 through an adjustable eccentric (not shown) to provide for adjusting the feed-stroke, and the link 23 is driven by the shaft 24 through an eccentric and the appropriate driving connections.

The stitching mechanism in the present machine includes two threaded loopers 25, each adapted to co-act with the corresponding one of the needles 16 in the formation of conventional two-thread chain-stitches. The loopers 25 are secured to one end of a carrier 26 that is pivoted at the opposite end to a looper-bar 27 in order that the loopers can be swung outwardly into a readily accessible position for threading. In addition to the usual loop-seizing and loop-shedding movements, the present loopers are also moved sidewise in loop-spreading movements as the thread is heldby loop-detaining mechanism hereinafter described. Therefore, the looper-bar 27 must be so mounted as to be longitudinally slidable and transversely pivotable about a point intermediate its ends, which is accomplished in the present device by fulcrumblocks 28. Suitable guides such as the plates 29 and 30 and block 31 are provided to guide and steady the looperbar in its movements. The guide-plate 30 which is adapted to overlie the looper-carrier 26 is secured to the under side of a needle-guide 32 mounted on the wall of the work-arm 12 as by screws 33, while the guideplate 29 and guide-block 31 are secured directly to the work-arm. I

Loop-seizing and loop-shedding movements, i. e., longitudinal reciprocation, is imparted to the looper-bar 27 by an oscillating arm 34 secured to a vertical shaft 35 journaled in the depending arm 11 and having the free end thereof slidingly projecting through an upstanding pin 36 journaled for free turning movement in the looper-bar 27. The shaft 35 is oscillated by a crank connection (not shown) with the shaft 24. I

Loop-spreading movements, i. e. transverse oscillation about the fulcrum-blocks 28, are imparted to the looperbar 27 by a link 37 pivoted at opposite ends to the looperbar and to a rock-arm 38 secured to the lower end of a vertical-shaft 39 journaled in the arm 11 and oscillated about its longitudinal axis by an eccentric connection (not shown with the shaft 24.

The loop-detaining mechanism comprises, an angle bracket 41 secured to the side wall of the work-arm 12 as by screws 40, and to which is pivotally secured as by a screw 42, a movable or locking element 43, shown per se in Fig. 7, and an arm 44. IThe bracket 41 also has secured thereto as by screws 45, a stationary element 46 shown per se in Fig. 6. The arm 44 and locking-element 43 are adjustably secured together, as by a screw 47, and the arm 44 includes an extended portion carrying a roller 48 adapted to cooperate with a slotted camblock 49 secured to the looper-bar 27.

With reference to Fig. 6, it-will be seen that the stationary element 46 comprises'a flaLS'ubStan'tiaIly-rectangular base bar 50 havi'ng.a' downwardly pcje'cting transverse rib s1 that i's seated in' aided/e52? a i lmaminnqmr or: it) \f tlll! and on w th; hm; ,0

Patented Sept. 27, 1955 the bracket 41 which serves to properly position the element 46 longitudinally of the work-arm 12. As seen in Fig. 3, the bracket 41 is adjustable by virtue of the enlarged apertures through which the screws extend. Apertures 53 are formed in the bar 50, which apertures are adapted to receive the screws and are transversely elongated to provide for adjustment. Secured to the one corner of the bar is an upstanding and forwardly extending arm 54 that carries at its upper end a flat head member 55 which is slotted, as at 56.

Referring to Fig. 7, the locking element 43 comprises a flat substantially pear-shaped base member 57 provided with a large aperture 58 adapted to receive the screw 42, and a smaller arcuate aperture 59 to adjustably receive the screw 47. Bent upwardly and forwardly from the base member 57 is an arm 60 from the end of which is bent a head member 61 provided with curved locking fingers 62. As seen in Figs. 1 and 5, the elements 43 and 46 are so dimensioned that, when they are mounted upon the bracket 41, the head 61 of the element 43 normally underlies the head 55 of the element 46 with the slots 56 and spaces between the fingers 62 in registry, and as seen in Figs. 3 and 4, when the elements are moved relatively, the locking fingers 62 of the head 61 are adapted to extend across the respective slots 56 in the head 46 at the mouth thereof to close the slots and thus convert them into enclosed apertures.

It will be obvious to those skilled in the art that the number of pairs of stitching instrumentalities employed would not alter the method of operation of the present machine. Thus, to simplify the following description, even though a two needle machine has been disclosed the operation thereof will be set forth as though it were provided only with a single needle and its cooperating looper. Also, for convenience, on the drawings the needlethread is designated Tn and the looper-thread T1.

In operation, the looper-bar 27 is actuated through a four-motion cycle in timed relation to the actuation of the needle. To effect the four-motion cycle, the looperbar is pivoted about the axis of the fulcrum blocks 28 and given lengthwise translation to impart substantially elliptical motion to the looper-carrying end thereof, the major axis of the elliptical path being longitudinally of the work-arm 12. During the loop-seizing movement of the stitching cycle, the looper moves in a substantially straight line up the arm toward the needle, or to the right as seen in Figs. 3 and 4, at the same time that the needle is being withdrawn from the work and casting a thread loop in the needle-thread Tn. The line of travel of the looper is designed to pass on the left side of the needle looking up the arm 12 as seen in Figs. 3 and 4, but sufficiently close thereto to enter the thread loop cast by the needle. As the needle is completely withdrawn from the work, the looper, which now extends through a loop in the needle-thread, continues to travel up the arm where the point thereof passes just beneath the head 61 of the element 43 of the spreader mechanism. One limb of the loop in the looper-thread Tl that has been carried through the loop in the needle-thread Tn by the looper is then carried into a slot 56 in the stationary element 46. This point in the stitching cycle is illustrated in Fig. 3.

The next motion in the four-motion cycle of the looperbar 27 which, of course, begins slightly before the termination of the previous motion, is a counterclockwise pivoting of the bar about the axis of the fulcrum blocks 28, which movement carries the cam-block 49 to the right looking up the arm 12 in Fig. 4. Sidewise movement of the cam-block causes the arm 44 and the attached locking link 43 to pivot about the screw 42, moving the head 61 of the locking element to the left looking up the arm 12 in Fig. 4. As the head 61 is moved relative to the stationary element head 55 in the direction indicated, the finger 62 moves into a position across the mouth of the slot 56, and since the one limb of the looper-thread is lodged in the slot at this time, it thus becomes locked therein.

The following motion in the cycle, which is the loopshedding motion, comprises a lengthwise sliding movement of the looper-bar 27 while in the sidewise pivoted condition. The loop in the looper-thread is held in the detaining mechanism and the legs thereof extend in divergent directions therefrom, one to the last stitch set in the work and the other to the looper. Thus, as the looper moves down the arm, the two legs of the looperthread are pulled out at an acute angle to each other.

Although the angle is small it is nevertheless made sufficiently wide so that the needle will with reasonable certainty pass between the two legs of the looper thread on its next penetration of the work. At the same time that the two legs of the looper-thread are being pulled out, the needle-thread loop through which the looper has previously passed, begins to slide off the looper, which movement is aided by the action of the thread take-up. The needle-thread loop that encloses the looper-thread loop acts to form a triangle with the two legs of the looper thread, through which the needle passes on its next penetration. To insure the proper formation of the thread triangle, theneedle-thread take-up action is timed so that it will not be so great as to cause the legs of the looper thread to be drawn together and thus destroy the spacing between them, until after the needle has entered therebetween.

Near the completion of the lengthwise motion of the loper-bar 27 down the work-arm 12, which position is illustrated in Fig. 4, the loop in the needle-thread is pulled off the looper. At this time, the needle has again penetrated the work and entered the thread triangle. Completion of the take-up action on the needle-thread sets the stitch in the work, which stitch comprises a loop of the needle-thread through which has been passed a loop of the looper-thread.

To complete the cycle, the looper-bar is pivoted clockwise about the axis of the fulcrum blocks 28 into position to begin again the cycle as above set forth, which pivotal movement acts to move the head 61 of the locking element 43 relative to the head 55, and thus opens the slots 56 therein and permits the looper-thread to be withdrawn therefrom and set in the work.

It will be obvious to those skilled in the art that various modifications may be made in the details of the looperthread-detainer without departing from the broader aspects to the present invention. For the lack of a better term, the looper-thread-detainer is referred to in the following claims as including a locking means which is intended to include all Structural equivalents of the mechanism disclosed. In particular, the provision of a looper-thread-detainer that positively locks or clamps the looper-thread is intended to be included within the scope of the term locking means as used in the following claims.

Having thus set forth the nature of the invention, what I claim herein is:

1. In a sewing machine having a work-support, a looper-barcarried longitudinally of the work-support, a looper secured to the looper-bar, and actuating mechanism adapted to impart four-motion cycles of movement to the looper-bar to produce movements of said looper about a substantially elliptical path the major axis of which is longitudinally of the work-support and the long sides of which constitute loop-seizing and loop-shedding movements, a stationary element carried by the worksupport including a head located adjacent the forward edge of the looper when at the end of its loop-seizing motion, a movable element pivotally carried by the worksupport and including a head located adjacent the head of the stationary element, a thread-slot formed in the head of one of said elements and a finger carried by the head of the other of said elements, said finger being adapted to project across the mouth of the slot when the elements are moved relative to each other, and operative connections between said movable element and said looper-bar whereby the movable element is actuated in timed relation to said looper.

2. In a sewing machine having a Work-arm, a looperbar slidingly and pivotally mounted intermediate its ends within the work-arm, a looper secured to the looper-bar, and actuating mechanism adapted to impart sliding and pivoting motions to said looper-bar to impart four-motion cycles of movement to the looper-bar to produce movement of said looper about a substantially elliptical path the major axis of which is longitudinally of the worksupport and the long sides of which constitute loop-seizing and loop-shedding movements, a stationary element carried by the Work-support including a head located adjacent the forward edge of the looper when at the end of its loop-seizing motion, a movable element pivotally carried by the work-support and including a head located adjacent the head of the stationary element, a thread-slot formed in the head of one of said elements and a finger carried by the head of the other of said elements, said finger being adapted to project across the mouth of the slot when the elements are moved relative to each other, and operative connections between said movable element and said looper-bar whereby the movable element is actuated in timed relation to said looper.

3. In a sewing machine having a needle and a looper, a needle-thread and a looper-thread carried by the needle and looper respectively, actuating mechanisms to drive the needle and looper through two-thread chain-stitch cycles during which said needle is adapted to be projected between two limbs of a triangle in the sewing threads, a loop-detainer including a releasable locking means for seizing and holding the looper-thread as the looper is being moved away therefrom, said locking means comprising a first element having a thread slot therein and a second element having a finger adapted to be projected across the mouth of the thread slot for closing the same, at least one of said elements being movable, and actuating means for producing relative motion between the first and second elements in timed relation to the actuation of the needle and the looper.

4. In a sewing machine having a needle and a looper, a needle-thread and a looper-thread carried by the needle and looper respectively, actuating mechanisms to drive the needle and looper through two-thread chain-stitch cycles during which said needle is adapted to be projected between two limbs of a triangle in the sewing threads, a loopdetainer including a releasable locking means for seizing and holding the looper-thread as the looper is being moved away therefrom, said locking means comprising a first element having a thread slot therein and a second element having a finger adapted to be projected across the mouth of the thread slot for closing the same, at least one of said elements being movable, and actuating means for producing relative motion between the first and second elements in timed relation to the actuation of the needle and the looper, said actuating means comprising operative connections between the movable element of said locking means and the looper-actuating mechanism.

5. In a chain-stitch sewing machine, a threaded looper having loop-seizing and loop-shedding movements, a threaded reciprocatory needle adapted to be actuated in timed and spaced relation with respect to said looper through a stitching cycle during which said needle is adapted to enter between two limbs of a triangle in the sewing threads, looper-thread detaining means comprising a releasable locking means having a pair of relatively movable locking elements for seizing the'looper-thread between the looper and the last stitch set in the work and for holding the looper-thread as the looper is moved away from the locking means to form a thread triangle into which the needle may enter, and means for actuating said locking means in timed relation to the actuation of said looper.

wise return movement, a threaded reciprocatory needle adapted to be actuated in timed and spaced relation with respect to said looper through a stitching cycle during which said needle is adapted to enter between two limbs of the looper-thread in the formation of a two-thread chain-stitch, looper-thread detaining means comprising a locking means constructed and arranged to receive the limb of the looper-thread between the looper and the last stitch set in the work during the loop-seizing movement of said looper, and actuating means for said looperthread locking means to close the same and to lock the looper-thread against withdrawal therefrom during the loop-spreading movements of the looper, to hold positively the looper-thread during loop-shedding movements of the looper, and to release the looper-thread during the sidewise return movements of the looper.

7. In a chain-stitch sewing machine, a threaded looper, actuating mechanism for imparting a four-motion cycle of actuation about a substantially elliptical path to said looper, said cycle of actuation including an endwise loopseizing movement, a sidewise loop-spreading movement, an endwise return loop-shedding movement and a sidewise return movement, a threaded reciprocatory needle adapted to be actuated in timed and spaced relation with respect to said looper through a stitching cycle during which said needle is adapted to enter between two limbs of the looper-thread in the formation of a two-thread chain-stitch, looper-thread detaining means comprising a locking means having a pair of relatively movable cooperating locking elements constructed and arranged to receive the limb of the looper-thread between the looper and the last stitch set in the work during the loopseizing movement of said looper, and actuating means for said looper-thread detaining means to close the same and to lock the looper-thread against withdrawal therefrom during the loop-spreading movements of the looper, to hold positively the looper-thread during loop-shedding movements of the looper, and to release the looperthread during the return movements of the looper.

8. In a sewing machine, a threaded looper actuated through a substantially four-motion stitching cycle including loop-seizing, loop-spreading, and loop-shedding movements, said looper being actuated in timed relation to the actuation of a cooperating threaded needle to enchain the threads of the looper and the needle to form a twothread chain-stitch in a stitching cycle during which said needle is adapted to enter between two limbs of the looper-thread, looper-thread-detaining means comprising locking means having a pair of relatively movable cooperating locking elements for receiving the limb of the looper-thread between the looper and the last stitch set in the work, and actuating means for said locking means to close the same and to hold positively the looper-thread as the looper is being moved away from said locking means.

9. In a sewing machine, a threaded looper actuated through ,a substantially four-motion stitching cycle including loop-seizing, loop-spreading, and loop-shedding movements, said looper being actuated in timed relation to the actuation of a cooperating threaded needle to enchain the threads of the looper and the needle to form a two-thread chain-stitch in a stitching cycle during which said needle is adapted to enter between two limbs of the looper-thread, and looper-thread-detaining means comprising a locking means having a pair of cooperating locking elements consisting of a stationary element and a movable element cooperating therewith to lock a thread from being freely withdrawn therefrom, one of said eleas the looper is being moved away from said locking 5 means.

References Cited in the file of this patent UNITED STATES PATENTS Zeier Mar. 6, 1934 Riviere et a1. July 7, 1936

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