US2688293A - Looper mechanism for sewing machines - Google Patents

Description

Sept. 7, 1954 R. A. HAYES ET AL LOOPER MECHANISM FOR SEWING MACHINES 6 Sheets-Sheet 1 Filed Aug. 3. 1951 FIG! l .ILI 1, AN

l II I IN 1 U q p' i INVENTORS.

ROBERT A. HAYES BY ARTHUR w. VIRTA, sR.

ATTORNEY.

Sept. 7, 1954 R. A. HAYES ETAL LOOPER MECHANISM FOR SEWING MACHINES 6 Sheets-Sheet 2 Filed Aug. 3. 1951 N l INVENTORS. ROBERT A. HAYES ARTHUR W. VIRTA,SR.

ATTORN EY.

Sept. 7, 1954 R. A. HAYES ETAL 2,688,293

LOOPER MECHANISM FOR SEWING MACHINES Filed Aug. 3, 1951 6 Sheets-Sheet I5 JNVENTORS. ROBERT A. HAYES ARTHUR w. VIRTA,SR.

ATTORNEY.

Sept. 7, 1954 R. A. HAYES ET AL LOOPER MECHANISM FOR sawmc; MACHINES 6 Sheets-Sheet 4 Filed Aug. 3, 1951 INVENTORS. ROBERT A. HA ARTHUR w. VIRTA,

YES SR.

ATTORNEY.

Sept. 7, 1954 R. A. HAYES ETAL LOOPER uzcmmxsm FOR sswzuc MACHINES 6 Shee'ts-Sheet -5 Filed Aug. 3. 1951 wbmb .8 0

q INVENTORS ROBERT A. HAYES ARTHUR w. vmm,sn. 1n!

ATTORNEY.

Sept. 7, 1954 R. A. HAYES ETAL LOOPER MECHANISM- FOR SEWING mcuxums 6 Sheets-Sheet 6 Filed Aug. 3, 1951 INVHVTORS.

ROBERT A. HAYES ARTHUR W. VIRTA,$R.

ATTORNEY.

Patented Sept. 7, 1954 UNITED STATES LOOPER MECHANISM FOR SEWING MACHINES Robert A. Hayes, Franklin Park, and Arthur W. Virta, Sn, Zurich Heights, 111., assignors to Union Special Machine Company, Chicago, 111., a corporation of Illinois Application August 3, 1951, Serial No. 240,106

14 Claims. 1

The present invention relates to sewing machines and more particularly to a throw-out means for the looper mechanism and a. cloth feeding device applicable to sewing machines having a plurality of needles and a plurality of loopers and needle guards which are adjustably mounted in the machine so as to form a plurality of parallel lines of stitching which may be spaced from one another as desired within the limits of adjustability. Certain principles of the present invention, however, are applicable to machines of other types including single needle machines.

For purposes of illustration, the present invention will be disclosed in a multiple needle machine wherein the loopers and needle guards oscillate in the direction of the line of feed of cloth during stitch formation. In this machine the loopers are of the two-motion type and spreaders are used in a well-known manner for the purpose of opening the loops of the looper thread in a direction transverse of the line of feed. In the cycle of stitch formation, the needles are projected through the work and into the level in which the loopers and needle guards reciprocate. When the needles are in such position the loopers and needle guards have been swung into a position where the major parts of the supporting structure therefor are behind the needles and certain of these parts would collide with the needles if it were attempted at this time to swing the loopers forwardly, for example, to throw the loopers out into accessible position for threading.

According to the present invention, the loopers are arranged to be uncoupled from the rocking mechanism in order that they may be swung forwardly into a threading position and it is a particular feature of the present invention that the means for effecting such uncoupling of the loopers cannot be operated at any time when the needles are down in such position as to present the danger of collision with any part of the looper mechanism.

In accordance with one embodiment of this invention the looper uncoupling means is constantly connected with the looper carrier but is disabled by means of an interlock during such time as the needles are down. In another form the looper uncoupling device includes parts on the looper carrier and the machine frame which come into interengaging position only at such time as the needles are out of the way of any part of the looper mechanism.

Inasmuch as the needles and the loopers with their associated needle guards are adjustable transversely of the line of feed for the purpose of varying the distance between at least some of the adjacent lines of stitching, the cloth feeding mechanism, particularly a cloth feeding mechanism of the type which employs intermeshing cloth puller rolls beyond the needles, must be of such width as to pull directly in the line of any and all lines of stitching which the machine may form in all positions of adjustment of the needles and loopers. When a cloth puller of such width is employed, some provision must be made to prevent the cloth from following the lower feed roll below the cloth plate.

According to the latter phase of the present invention, there has been provided a guard particularly suitable for maintaining the cloth at the level of the cloth plate during its traverse of the feed rollers.

It is an object of the present invention to provide looper throw-out and cloth feeding mechanism of the type described above for cooperation with a sewing machine of the multiple needle type, although certain features of the looper throw-out mechanism are adaptable to machines of other types.

In the drawings:

Fig. l is an elevational view of one end of a sewing machine embodying the present invention, with parts in section and parts removed for purposes of illustration;

Fig. 2 is a generally horizontal sectional view of the machine with the cloth plate removed to reveal parts of the mechanism of the present invention;

Fig. 2a is a detail sectional view taken along y the axis of the main drive shaft of the machine;

Fig. 3 is a front elevational View of the machine with parts in section and parts broken away;

Fig. 3a is a vertical section taken along the line 3a3a in Fig. 1;

Fig. 4 is an enlarged fragmentary top plan view showing the relationship between the looper mechanism and the Spreaders;

Fig. 5 is an exploded View of the looper mechanism and throw-out mechanism therefor;

Figs. 6, '7 and 8 are fragmentary detailed views illustrating the operation of the looper throwout mechanism;

Fig. 9 is a view similar to Fig. 5 but showing a modified form of the invention; and

Fig. 10 is a fragmentary vertical sectional view showing the relationship between the modification illustrated in Fig. 9 and the feed dog tilting mechanism of a sewing machine in which it may be embodied.

Referring now to the drawings:

The frame of the machine comprises a base 20, having a work supporting surface 22 from one end of which rises a standard 24 and over which extends an overhanging arm 26 terminating in a needle head 28. The main drive shaft of the machine is made up of two aligned sections 30 and 32 connected by a coupling 34 and 3 this shaft extends longitudinally of the machine in suitable bearings formed in the base 20. As seen in Figs. 2 and 3 the right hand section of the main drive shaft projects from the frame and carries a combined hand wheel and pulley 36 through which power may be supplied from any suitable source. The section 30 has formed therein a crank portion 38 carrying a strap member 40 connected through a pitman 42, ex-

tending upwardly through the standard 24, to l the right hand end of a needle lever 44 pivoted at 46 in the overhanging arm 26. The needle lever 44 extends forwardly into the needle head 28 where it is pivotally connected with a needle bar 48 adapted to be verticaly reciprocated in the needle head in response to rocking of the needle lever 44 when the main drive shaft is rotated.

The needle bar 43 carries one or more needles 50, there being four such needles illustrated in the particular embodiment of this invention chosen for illustration. The needles 50 are clamped in any desired positions relative to one another in a frame 49 carried by the needle bar 48.

Cooperating with the needles 50 in the simultaneous formation of four lines of stitching, there is provided a looper mechanism, generally indicated at 52, having provision for the handling of four looper threads. of the two-motion type arranged to cooperate with spreaders 54 carried by a longitudinally reciprocable spreader bar 56. As shown particularly in Fig, 4, the spreaders 54 are in the form of fingers, one for each of the threads handled by the looper mechanism. The spreaders 54 project through suitable openings in the bar 56 and are secured therein as by set screws 58. The spreader bar 56 is carried in suitable sliding hearings in the frame for reciprocation longitudinally of the machine and to the latter end is connected through a link 60 (see Fig. 3) with a rock arm 62 fixed to a rock shaft 64 extending transversely of the machine and arranged to rock in suitable timed relation with the rocking of the looper mechanism 52.

As seen in Fig. 2, the shaft 64 extends across the frame of the machine where it is received in a bearing 66 to which is clamped a rock arm 68 (see Fig. 2a). lower end of a pitman 10 carried by an eccentric strap 12 mounted upon an eccentric l4 fixed to the section 30 of the main drive shaft. It will be apparent that, through the linkage just described, rotation of the main drive shaft will be effective to reciprocate the spreader bar 56.

The looper mechanism 52 is also rocked in response to rotation of the main drive shaft. For this purpose a looper rock shaft 16 extends longitudinally of the machine and is received in suitable bearings within the frame. On its forward end the looper rock shaft carries the looper mechanism 52 while toward its rearward end it has clamped thereto an arm 18 (see Fig. 5)

which is pivoted at 60 to a lug 82 formed upon an eccentric strap 84 surrounding the main drive shaft section 30. The eccentric strap 84 rides on an eccentric 66 fixed to the main drive shaft section 30.

The looper rock shaft 16 also has clamped thereto a looper driving arm 88 having a perforation 90 therein with which a suitable part of the looper mechanism 52 engages when the latter is in position for operation.

The looper mechanism 52 includes a looper The looper mechanism is The arm 68 is connected to the frame or carrier 92 having a smooth bore 94 freely rotatable upon the looper rock shaft 16. Spaced lugs 96 and 98 formed on the looper frame are perforated to receive a plunger I00 having a tapered end I02 adapted to be received in the perforation of the looper driving arm 88. The plunger I00 is urged by a spring I04, one end of which bears against lug 96 and the other end of which bears against a flange I06 fixed to the plunger I00, into a position such as shown in Fig. 4 in which the tapered end I02 is projected into the perforation 90. In this position of the parts the looper mechanism 52 is coupled with the rock shaft 16. At its opposite end the plunger I00 is provided with a head I08 by which the plunger may be retracted against the force of spring I04 to withdraw the tapered end I02 from the perforation 90 whereby to uncouple the looper mechanism 52 from looper driving arm 88.

The looper frame or carrier 92 is provided with a rail IIO of dove-tail cross section upon which may be adjustably mounted the desired number of loopers H2 and needle guards H4. As shown in the drawings there are four loopers H2 and four needle guards II4 which may be secured in desired adjusted position along the rail IIO as by set screws II6. While each looper H2 and its associated needle guard II4 may be indi vidually adjustable if so desired, the mechanism shown provides for adjustment of these elements in pairs. Thus two double seams may be formed with the distance therebetween adjusted as desired while the spacing within each seam remains constant.

As will be apparent from a consideration particularly of Fig. l, the looper mechanism just described occupies a position beneath the cloth plate in which it is relatively inaccessible. According to the present invention, provision is made for swinging the looper mechanism downwardly and to the right as vi wed in Fig. 1, to bring the loopers II2 into an accessible position for threading. Such position is illustrated in broken lines in Fig. 1. In general, the present invention provides a mechanism for uncoupling the looper mechanism 52 from the looper rock shaft '16 so that the looper mechanism may rotate freely about the rock shaft and thus be swung into an accessible position as aforesaid. The coupling mechanism is provided with an interlock or other form of disabling means which is effective to prevent swinging of the looper mechanism into a threading position when other parts of the machine are in positions such as to interfere with such swinging movement.

In a cycle of stitch formation, the needles 50 will be projected downwardly into the position shown in Fig. 1 wherein the points of the needles lie below the loopers l I2 and they will thereafter be raised to a position above the cloth plate 22 as illustrated in Figs. 6 and '7. During this same time the loopers will rock with the rock. shaft l0 in proper timed relation with the movement of the needles so as to carry the looper threads to the right of the needles 50 as viewed in Fig. 1. The spreaders 54 will thereafter move longitudinally of the machine to spread the looper threads into an open loop so that the needles and the needle threads carried thereby may be projected downwardly through such loops. After this operation the loopers will return to their initial positions as shown in Fig. 1. During a portion of each cycle of operation therefore, the needles 50 will be projected below the level of the loopers H2 and in such position they would be struck by certain parts of the looper and needle guard assembly if it were attempted to swing the looper mechanism '52 toward a threading position. The interlock or disabling mechanism referred to above is so arranged that the looper mechanism cannot be moved toward the threading position at any time that the needles 50 are within the path of the loopers II2. However, during the portion of the cycle in which the needles are in or near their upper position, the looper mecha nism may be thrown out for threading,

Referring now particularly to Figs. 5 through 8, one embodiment of the mechanism just discussed will be specifically described. In Fig. 5 the looper mechanism is shown in exploded relationship with the looper rock shaft I6 and various other parts heretofore described.

In Fig. 6 the needles 5B are in a position above the looper mechanism so that the looper mechanism may be swung into a threading position if so desired. In Fig. '7 the looper mechanism is shown swung into threading position. In Fig. 8 as in Fig. 1, the needles as have been projected downwardly below the level of the loopers H2 and in such position the looper mechanism cannot be swung to the right without collision. An interlocking mechanism is shown in these views, which mechanism is effective to prevent uncoupling of the looper mechanism when the parts are in or near the position shown in Figs. 1 and 8 and which will permit uncoupling when the parts are in or near the position shown in Figs. 6 and 7.

For the purposes thus generally described, the

preferred form of the present invention provides a rock shaft I It, (see Figs. 2 and 3) rotatably mounted in a sleeve I fixed in a suitable opening in the lower portion of the frame. One end of the rock shaft IIB extends forwardly into a position accessible from the front of the machine and carries a knurled knob I22 by which the rock shaft may be manipulated. The rock shaft IIB is also free for limited sliding movement within the .sleeve I20, the base of the knob I22 serving to limit such sliding movement inwardly of the machine and a split ring I24 fitted upon the shaft IIe serving to limit motion outwardly of the machine. As shown in Fig. 2 the inner end of the rock shaft H8 is threaded to receive a screw I26 by which a lever I28 is secured to the shaft I18. Referring now to Fig. 5, it will be observed that the lever I28 is bifurcated and straddles the plunger IilIi in the region between the head Hi8 and the lug 96. The length of the bifurcated lever I28 is such that it remains engaged with the plunger I00 throughout the swinging movement of the looper mechanism 52 both in normal operation thereof and in the movement thereof to threading position. Preferably a spring tilt and washer I32 are arranged between the lug 96 and the inner face of the bifurcated lever I23 (see Fig. 2). The spring I is weaker than the spring I04 and serves merely to confine the bifurcated lever I28 against the head of the screw I08.

It will be apparent from the construction just described that the lever I28 will rock with the looper mechanism I52 but in an opposite angular direction. The lever i293 is provided with a tail I34 which rocks into and out of a position to engage a tooth I36 formed on a bracket I38 secured to the frame of the machine (see Figs. 2 and 3). The tail its and tooth I36 are so proportioned that the tail will lie below and behind the tooth at all times when the needles are below the cloth plate to such an extent as to interfere with movement of the looper mechanism into threading position. so long as the tail I34 lies behind the tooth I36 the rock shaft I I8 cannot be pulled forward and therefore the plunger I00 cannot be pulled forward to uncouple the looper mechanism from the looper actuating lever 88 (see Figs. 1, 3 and 8). At all times in which the needles 53 are above the level of the loopers the tail I34 will lie above the tooth 536 (see Figs. 6 and '7). Under the latter conditions the rock shaft I I B and plunger we may be pulled forward to disengage the tapered end I02 from the perforation 9e thus to uncouple the looper mechanism 52.

When thus uncoupled, the looper mechanism may be swung clockwise as viewed in Fig. l by an anti-clockwise rotation of the knob I22 to bring the looper mechanism into a threading position. Furthermore, if so desired, there may be provided a torsion spring I4!) (see Fig. 5) extending between the looper driving arm 88 and the looper frame 92 and so arranged as to tend constantly to swing the looper frame in a clockwise direction or toward threading position. If such spring I40 is provided the looper mechanism will be automatically thrown out whenever the operator pulls the knob I22 provided, of course, that the tail I34 lies above the tooth I36.

After threading the loopers II2 the operator may rotate the knob I22 in a clockwise direction to return the looper mechanism 52 toward operative position. When such position is reached the spring I04 on the plunger I39 will be effective to project the tapered end Hi2 into the perforation 90 and the looper mechanism will be coupled with the looper rock shaft 78. For the latter operation the knob I22 need not be pulled out since the tapered end I02 of the plunger I530 will cam across the face of the looper actuating lever 88, compressing the spring Hi l until it reaches a position to snap into the perforation 98. Actually it is preferred that the knob I22 be pressed inwardly during return of the looper mechanism, such operation being possible because the Weaker spring I30 is readily compressed, inasmuch as this avoids the possibility of the knob I22 being snapped out of the operators fingers when the plunger I00 seats in the actuating lever 88.

A modified and simplified form of the invention is illustrated in Figs. 9 and 10. In this modification an actuating knob is provided on a frame part of the machine and cooperating parts are provided between the knob and looper which are in position for engagement only when the loo-per mechanism has been rocked into a position which it assumes when the needles are out of the way. Since such mechanism does not include the constant connection between the looper mechanism and the actuating knob, as provided in the foregoing codification, it is necessary to provide a spring or equivalent means for throwing the looper mechanism out when it is disengaged by the actuating knob. Furthermore, in this simplified form of the invention the actuating knob cannot be used to reset the looper mechanism after threading and such operation must be performed manually.

In the modification shown in Figs. 9 and 10, the looper mechanism 52' is freely rotatable upon a looper rock shaft 16 which in turn is rocked by mechanism which may correspond in all details with that described above in connection with Figs. 1 through 8. A looper driving arm 88 having a perforation 90' therein is secured to the rockshaft 16 and the looper mechanism 52' includes a plunger I having a tapered end I02 to enter the perforation 90 for coupling the looper mechanism with the rock lever 66. The plunger I00 is provided with an expansive spring I04 which bears against a flange I06 fixed to the lunger I00 so as constantly to urge the plunger I00 to the right as viewed in Fig. 9.

The plunger I00 .is provided with a head I06 to which there is secured a frusto-conical ring I42 having an outside diameter considerably greater than that of the plunger I 00'.

A torsion spring I40 is stressed between the lever 88 and the looper mechanism 52 which constantly urges the latter to rotate clockwise about the rock shaft 16. Thus, whenever the plunger I00 is moved toward the left, as viewed in Fig. 9, to withdraw the tapered end i 02' from the perforation 90, the looper mechanism will automatically swing forwardly into the threading position shown in Fig. 10.

In this modification of the invention, collision between the looper mechanism and needles is avoided by so positioning an actuating knob that it can be effective to withdraw the plunger I00 only when the needles are out of the way. To this end a rod I 44 is mounted for reciprocation in a sleeve I46 fixed to a portion of the base 20. The rod I44 is provided at one end with an actuating knob I48 and at the other end with a frusto-conical ring I50 secured to the rod as by a screw I52. An expansive spring I54 is positioned between the end of the sleeve I46 and a flange I56 fixed to the rod I44 so as constantly to urge the rod toward the right as viewed in Fig. 9.

The relative size and positions of the frustoconical rings I42 and I50, carried respectively by the looper mechanism '52 and the rod I44, are such that portions thereof will become horizontally aligned only when the looper mechanism is rocked substantially into a position such as that shown in full lines in Fig. 10. When this occurs the rod I44 may be pulled forwardly and engagement between the fiat surfaces of the rings I50 and I42 will cause retraction of the plunger I00 to uncouple the looper mechanism from the looper driving arm 88' whereupon the looper mechanism will be thrown forwardly into threading position by action of the torsion spring I40. Such position is illustrated in broken lines in Fig. 10. After threading the looper mechanism is returned to operative position by manual operation during which the tapered end I02 of plunger I00 will be cammed across the face I58 of the lever 88 to a position wherein it will snap into the perforation 90.

At all times during which the needles are projected below the cloth plate into a position such as to interfere with throwing out of the looper mechanism, the ring I42 will not be horizontally aligned with any portion of the ring I50 and therefore it will be impossible to uncouple the looper mechanism by actuation of the knob I48.

In Figs. 1, 2 and 3, there is shown a cloth pulling apparatus embodying an improvement particularly useful in connection with a multiple needle flat bed sewing machine in which the loopers rock in the direction of cloth feed. This improvement relates to a guard arranged to prevent cloth from following the lower feed roll below the surface of the cloth plate.

The mechanism just referred to includes an upperfeed roll I60 which is provided with longitudinally extending teeth I62. The roll 60 is fixed to a shaft I64 to which there is also fixed a spiral gear I66 meshing with a smaller spiral gear I68 fixed to a vertical shaft I61 driven through a coupling I69 by a clutch mechanism I10. The clutch mechanism I10 imparts a step by step rotation to the feed roll I and may be of the form shown in United States Letters Patent No. 1,692,130 granted November 20, 1928 to Long et al.

The shaft I64 for the upper feed roll I60 is carried in .a frame I6I which is yieldably urged downwardly by a spring I63 to place the roll I60 in feeding position. A lever I having a cam I1.I arranged to abut a pin I13 on the frame I6I may be provided to lift the frame I6I and feed roll I60 when desired.

A lower idler feed roll I12 having longitudinally extending teeth I14 is carried by a shaft I16 .freely rotatable in suitable bearings in the base 20 of the machine. 'Ieeth I14 are of a size to mesh with the teeth I62 of the upper roll I60 when the latter is lowered into operative position.

The lower feed roll I12 is of such diameter, as clearly shown in Fig. 1, that the roots of the teeth I14 lie in a plane no higher than and preferably slightly below the plane of the top of the cloth plate 22. A circumferential groove I18 (see Fig. 3a) is formed in the lower feed roll I12, said circumferential groove being somewhat deeper than the teeth I14 for a purpose to be described.

The cloth plate 22 has a generally rectangular opening I formed therein. Preferably the cloth plate is curved downwardly along the longitudinal edges of said rectangular opening I80 to form rounded lips I82 which project slightly below the lower surface of the cloth plate thus providing smooth rounded edges extending transversely 'of the direction of cloth feed. A wire guard I 84 is positionedacross the opening I80 in the directiono'f cloth feed so as to lie within the groove I18 of the lower feed roll I12. Preferably the guard I84 is formed of wire which may be bent around and under the lips I82 where the ends may be secured as by soldering, welding 'or the like in shallow recesses in the lower surface of the cloth 'plate 22. The guard I84 .is;so positioned that the upper surface of the :horizontally extending portion 185 thereof lies .substantially within the plane tangent to the roots of the teeth 0f lower feed roll I12 adjacent the upper surface of the cloth plate 22 and parallel therewith. Thus the central part 'of the guard 'wire lies wholly within the groove I18 in thelower feed roll I12 and it is not necessary to provide -'a-groove in the upper feed ro'll I60.

The horizontally'extending portion I85 of the guard 186 serves to prevent cloth from followin the lower 'roll I12 into the recess I80 where it might become entangled with operating parts of the machine. Obviously a plurality of guards such as I84 may 'be provided if so desired.

The simple and effective means, including the guard I84, just described is of particular utility in a machine of the general typedisclosed herein.

' It will be apparent that in-certain positions of adjustment at least, the four lines of stitching formed by thismachine willextend over a considerable width of'cloth. The feed rolls I60 and 112 :must therefore have an axial length sufficient to span-the lines of stitching at maximum spacing so as to pull directly inline with all of said lines'of'stitching. With rolls of such length there is. increased likelihood of the clothdropping below the far edgeof the opening Land the guard I84 thus assumes a particularly important status.

We claim:

1. In a sewing machine the combination of a bed, work feeding means, a reciprocating needle, looper mechanism rochably mounted on said bed, looper rocking means for rocking said looper mechanism through a path a portion of which intersects a portion of the path of said needle, operating means for driving said needle and looper rocking means in coordinated relation to provide a stitch forming cycle, movable means for coupling said looper mechanism with said rocking means, and a looper throwout means for moving said movable means to effect uncoupling of said looper mechanism from said rocking means, said looper throwout means including a first member carried by said bed and a second member connected with said looper mechanism and movable relative to said first member as an incident to rocking of said looper mechanism, one of said members being movable bodily to effect said uncoupling, said members having cooperating portions arranged for coaction during only a part of the rocking movement of said looper mechanism in the course of a stitch forming cycle and serving to render said looper throwout means ineffective to uncouple said looper mechanism from said rocking means at any time during which said needle occupies any portion of its path which intersects the path of said loo-per mechanism.

2. In a sewing machine the combination of a frame, a main drive shaft, work feeding means, a reciprocating needle, connections from said shaft for reciprocating said needle, looper mechanism, means mounting said looper mechanism on said frame for rocking movement through a path a portion of which intersects a portion of the path of the needle, a rock shaft operatively connected with said main shaft, coup-ling means for connecting said looper mechanism with said rock shaft, said coupling means including means movable with said looper mechanism during rocking thereof and movable relatively to said looper mechanism and said rock shaft between a position in which it connects said looper mechanism with said rock shaft for rocking of said looper mechanism and a position in which said looper mechanism is uncoupled from said rock shaft,

actuating means mounted on the frame of said machine and accessible to the operator thereof, and means operatively connecting said actuating means with said coupling means, said connecting means including parts which are movable relatively to one another as an incident to the rocking of said looper mechanism, said parts when in certain relative positions enabling movement of said coupling means by said actuating means to uncoupling position and in other relative positions preventing such movement of said coupling means by said actuating means, said certain relative positions being assumed by said parts only during such time that said needle occupies a portion of its path which does not intersect the path of said looper mechanism.

3. In a sewing machine the combination of a bed, work feeding means, a reciprocating needle, looper mechanism rockably mounted on said bed, looper rocking means for rocking said looper mechanism through a path a portion of which intersects a portion of the path of said needle, operating means for driving said needle and said looper rocking means in coordinated relation to provide a stitch forming cycle, movable means for coupling said looper mechanism with said rocking means, and a looper throw out means including a first member carried by said bed, a second member connected with said looper mechanism and movable relative to said first member as an incident to rocking of said looper mechanism, and a manually operable element connected with one of said members and arranged to move said movable means to eifect uncoupling of said looper mechanism from said rocking means, the movement of said second member relative to said first member placing said members in a first relationship: during a selected portion of each stitch forming cycle in which said element is operable at will to uncouple said looper mechanism from said rocking means and into a second relationship during a different portion of each stitch forming cycle in which efiective operation of said element is prevented, and means for moving said looper mechanism when uncoupled into a position readily accessible for threading.

4. In a sewing machine the combination of a bed, work feeding means, a cloth plate, a. reciprocating needle, looper mechanism rockably mounted beneath said cloth plate, looper rocking means for rocking said looper mechanism to cooperate with said needle in the formation of a line of stitches, operating means for driving said needle and said looper rocking means in coordinated relation to provide a stitch forming cycle, movable means for coupling said looper mechanism with said rocking means, and a looper throwout, a first member carried by said bed, a second member connected with said looper mechanism and movable relative to said first member as an incident to rocking of said looper mechanism, and a manually operable element connected with one of said members and arranged to move including means, said movable means to effect uncoupling of said looper mechanism from said rocking means, means for moving said uncoupled looper mechanism downwardly and outwardly of said cloth plate into a position readily accessible for threading and through a path at least a portion of which intersects a portion of the path of said needle, the movement of said second member relative to said first mem ber placing said members in a first relationship during a portion of each stitch cycle in which said looper throwout means is operable at will to uncouple said looper mechanism from said rocking means and into a second relationship during a different portion of each stitch cycle in which operation of said looper throwout means is prevented at any time during which said needle occupies any portion of its path which intersects the path of said looper mechanism.

5. In a sewing machine the combination of a bed, work feeding means, a reciprocating needle, looper mechanism rockably mounted on said bed, looper rocking means for rocking said looper mechanism through a path a portion of which intersects a portion of the path of said needle, operating means for driving said needle and said looper rocking means in coordinated relation to provide a stitch forming cycle, a longitudinally movable plunger carried by said looper mecha nism and adapted in one position to effect coupling between said looper mechanism and said rocking means, and a looper throwout means including a first member carried by said bed, a second member connected with said looper mechanism and movable relative to said first member as an incident to rocking of said looper 1 l mechanism, and a manually operable element connected with one of said members and arranged to move said plunger longitudinally to effect uncoupling of said looper mechanism from said rocking means, the movement of said second member relative to said first member placing said members in a first relationship during a portion of each stitch cycle in which said looper throwout means is operable at will to uncouple said looper mechanism from said rocking means and into a second relationship during a different portion of each stitch cycle in which operation of said looper throwout means is prevented at any time during which said needle occupies any portion of its path which intersects the path of said looper mechanism.

6. In a sewing machine the combination of a bed, work feeding means, a reciprocating needle, looper mechanism rockably mounted on said bed,

looper rocking means for rocking said looper P mechanism through a path a portion of which intersects a portion of the path of said needle, operating means for driving said needle and said looper rocking means in coordinated relation to provide a stitch forming cycle, a longitudinally movable plunger carried by said looper mechanism and adapted in one position to effect coupling between said looper mechanism and said rocking means, and a looper throwout means including a first member carried by said bed, a second member connected with said looper mechanism and movable relative to said first member as an incident to rocking of said looper mechanism, and a manually operable element connected with one of said members and ar- :u

ranged to move said plunger longitudinally to effect uncoupling of said looper mechanism from said rocking means, and means for moving said uncoupled looper mechanism into a position readily accessible for threading, the movement of said second member relative to said first member placing said members in a first relationship during a portion of each stitch cycle in which said looper throwout means is operable at will to un couple said looper mechanism from said rocking means and. into a second relationship during a different portion of each stitch cycle in which operation of said looper throwout means is prevented at any time during which said needle occupies any portion of its path which intersects the path of said looper mechanism.

7. In a sewing machine the combination of a bed, work feeding means, a reciprocating needle, looper mechanism rockably mounted on said bed,

looper rocking means for rocking said looper mechanism to cooperate with said needle in the formation of a line of stitches, operating means for driving said needle and said looper rocking means in coordinated relation to provide a stitch forming cycle, a longitudinally movable plunger carried by said looper mechanism and adapted in one position to effect coupling between said looper mechanism and said rocking means, and a looper throwout means including a first member carried by said bed, a second member connected with said looper mechanism and movable relative to said first member as an incident to rocking of said looper mechanism, and a manually operable element connected with one of said members and arranged to move said plunger longitudinally to effect uncoupling of said looper mechanism from said rocking means, and means for moving said uncoupled looper mechanism into a position readily accessible for threading through a path at least a portion of which intersects a portion of the path of said needle, the movement of said second member relative to said first member placing said members in a first relationship during a portion of each stitch cycle in which said looper throwout means is operable at will to uncouple said looper mechanism from said rocking means and into a second relationship during a different portion of each stitch cycle in which operation of said looper throwout means is prevented at any time during which said needle occupies any portion of its path which intersects the path of said looper mechanism.

8. In a sewing machine the combination of a bed, work feeding means, a vertically reciprocating needle, looper mechanism mounted on said bed for oscillation in vertical planes, looper rocking means for rocking said looper mechanism to cooperate with said needle in the formation of a line of stitches, operating means for driving said needle and said looper rocking means in coordinated relation to provide a stitch forming cycle, a longitudinally movable plunger carried by said looper mechanism and adapted in one posi tion to effect coupling between said looper mechanism and said rocking means, and looper throwout means including a first member carried by said bed, a second member connected with said looper mechanism and movable relative to said first member as an incident to rocking of said looper mechanism, and a manually operable element connected with one of said members and arranged to move said plunger longitudinally to effect uncoupling of said looper mechanism from said rocking means, and means for moving said uncoupled looper mechanism into a position readily accessible for threading through a path at least a portion of which intersects a portion of the path of said needle, the movement of said second member relative to said first member placing said members in a first relationship during a portion of each stitch cycle in which said looper throwout means is operable at will to uncouple said looper mechanism from said rocking means and into a second relationship during a different portion of each stitch cycle in which operation of said looper throwout means is prevented at any time during which said needle occupies any portion of its path which intersects the path of said looper mechanism.

9. In a sewing machine the combination of a bed, means for feeding material in a pro-determined direction through said machine, a vertically reciprocating needle, looper mechanism mounted on said bed for oscillation in a path parallel with the line of feed and a portion of which intersects a portion of the path of said needle, operating means for driving said needle and said looper rocking means in coordinated relation to provide a stitch forming cycle, a longitudinally movable plunger carried by said looper mechanism and adapted in one position to effect coupling between said looper mechanism and said rocking means, and a looper throwout means in eluding a first member carried by said bed, a

second member connected with said looper mechanism and movable relative to said first member as an incident to rocking of said looper mechanism, and a manually operable element connected with one of said members and arranged to move said plunger longitudinally to effect uncoupling of said looper mechanism from said rocking means, means for moving said uncoupled looper mechanism into a position readily accessible for threading through a path at least a portion of which intersects the path of said needle, the movement of said second member relative to said first member placing said members in a first relationship during a portion of each stitch cycle in which said looper throwout means is operable at will to uncouple said looper mechanism from said rocking means and into a second relationship during a dilferent portion of each stitch cycle in which operation of said looper throwout means is prevented at any time during which said needle occupies any portion of its path which intersects the path of said looper mechanism.

10. In a sewing machine the combination of a bed, work feeding means, a reciprocating needle, looper mechanism rockably mounted on said bed, looper rocking means for rocking said looper mechanism through a path a portion of which intersects a portion of the path of said needle, operating means for driving said needle and said looper rocking meansin coordinated relation to provide a stitch forming cycle, said looper rocking means including a rock lever having an opening formed therein, a longitudinally movable plunger carried. by said looper mechanism and adapted in one position to enter the opening in said rock lever to effect coupling between said looper mechanism and said rocking means, resilient means urging said plunger toward said position, and a looper throwout means including a first member carried by said bed, a second member connected with said looper mechanism and movable relative to said first member as an incident to rocking of said looper mechanism, and

a manually operable element connected with one of said members and arranged to move for moving said plunger longitudinally against said yieldable means to withdraw the same from said opening in said rock lever to efiect uncoupling of said looper mechanism from. said rocking means, said uncoupled looper mechanism being free to move into a position readily accessible for threading, the movement of said second member relative to said first member placing said members in a first relationship during a portion of each stitch cycle in which said looper throwout means is operable at will to uncouple said looper mechanism from said rocking means and into a second relationship during a different portion of each stitch cycle in which operation or said looper throwout means is prevented at any time during which said needle occupies any portion of its path which intersects the path of said looper mechanism.

11. The apparatus set forth in claim 10 in which said second member is constantly connected with said plunger and comprises a slotted lever straddling said plunger, and in which is provided means for rotating said slotted lever to move said uncoupled looper mechanism either towards or from its threading position.

12. The apparatus set forth in claim 10 in which said means for moving said longitudinally movable plunger includes an operating knob accessible from the exterior of said sewing machine, and in which said second member comprises a lever constantly connecting said operating knob with said plunger and which rocks in response to the movements of said looper mechanism in a stitch forming cycle, and in which said first member comprises a stop fixed with respect to the frame of said machine, and a projection carried by said second member which rocks with said second member into such relationship with said first member as to prevent uncoupling of said looper mechanism at any time during a cycle of stitch formation in which said needle occupies any portion of its path which intersects the path of said looper mechanism.

13. The apparatus set forth in claim 10 in which said means for moving said longitudinal plunger comprises a rod mounted in the bed of said sewing machine for longitudinal reciprocation in a fixed path substantially parallel with the path of movement of said plunger said first member being mounted on said rod, and in which said second member comprises means on said plunger which moves into interengaging relation with said first member in which longitudinal movement of said rod may be transmitted to said plunger only when said looper mechanism is rocked in a cycle of stitch formation into a position which it occupies during the time that said needle is in positions outside that portion of its path of travel which intersects any portion of the path of travel of said looper mechanism.

14. In a sewing machine the combination of means for feeding material in a predetermined direction through said machine; a plurality of needles; means for verticall r ciprocating said needles, a cloth plate; looper mechanism located beneath said cloth plate including a plurality of loopers corresponding respectively with said plurality of needles, and a needle guard associated with each of said loopers, said loopers and said needle guards being mounted for oscillation in vertical planes parallel with the line of feed; means for rocking said looper mechanism to move said loopers and said needle guards in said planes to cooperate with said needles in the formation of a plurality of parallel lines of stitching, said looper mechanism being thus rocked through paths having portions intersecting portions of the paths of said needles, said rocking means being so timed with said means for vertically reciprocating said needles that said needles and said looper mechanism occupy the intersecting portions of their respective paths at diilerent times within a cycle of stitch formation; and looper throw-out means for uncoupling said looper mechanism from said rocking means and swinging said looper mechanism downwardly and outwardly from said cloth plate into a position readily accessible for threading said loopers, said looper throw-out means including an actuating knob accessible from the exterior of said machine, a longitudinally reciprocable plunger carried by said looper mechanism and having an end portion adapted in one position of said plunger to effect coupling between said looper mechanism and said rocking means, means including a bifurcated lever straddling said plunger and rigidly connected with said actuating knob for maintaining a constant connection between said plunger and said actuating knob whereby movement of said knob may be effective to withdraw said References Cited in the file of this patent UNITED STATES PATENTS Name Date Zeier et al June 6, 1933 Hacklander Jan. 28, 1936 Number

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