US2419698A - Thread case and carrier therefor for lock-stitch sewing machines - Google Patents

Description

April 29, 1947. R WOQD 2,419,698

I THREAD-CASE AND CARRIER THEREFOR FOR LOCK-STITCH SEWING MACHINES Filed Aug. "21, 1945 Patented Apr. 29, 1947 2,419,698 THREAD CASE AND CARRIER THEREFOR FOR LOCK-STITCH SEWING MACHINES Alfred R. Wood, Bridgeport, Conn., assignor to The Singer Manufacturing Company, Eliza- I both, N. J a corporation of New Jersey Application August 21, 1945, Serial No. 611,722

28 Claims. 1

. the center of the cop, or a conventional bobbin,

inwhich the thread is delivered from the periphery of the bobbin.

Another object of the invention is to provide a thread-case having thread-directing means capable of leading the bobbin-thread from its supply to a thread-tensioning device and thence to the work in a free condition, thus eliminating any objectionable binding of the thread in its passage from the supply to the work.

A further objective of the present invention is the provision of an improved thread-controlling means which is uniform in its action and not afiected. by variations in the size of the thread, not sensitive and not in need of close adjustment when changing from one diameter of thread to a diiferent diameter of thread.

A still further object of the invention is the provision of simplified means for encouraging the free passage of the needle-thread loop about the thread-case and past the usual rotationrestraining projection, which means also functions to absorb the needle-thread-loop and thereby control the same as the loop is cast oif and is being pulled up by the action of the take-up.

With the above and other objects in view, as will hereinafter appear, the invention comprises the devices, combinations and arrangements of parts hereinafter set forth and illustrated in the accompanying drawings of a. preferred embodiment of the invention, from which the several features of the invention and the advantages attained thereby will be readily understood by those skilled in the art.

In the accompanying drawing:

Fig.1 represents a fragmentary front elevational view, partly in section, of a sewing machine equipped with a horizontal axis rotary loop-taker embodying the invention.

Fig. 2 represents a front elevational View of the thread-case carrier.

Fig. 3 represents a left side elevational view,

partly in section, of the rotary loop-taker, showing the manner in which the thread-case carrier is journaled in the loop-taker body.

Fig. 4 is a perspective view of the thread-case carrier, showing clearly the preferred shape and location of the keeper-apertures for the threadcase latch.

Fig. 5 represents a top case carrier.

Fig. 6 represents a right side elevational View of the thread-case.

Fig. 7 represents a left'side elevational view of the thread-case.

' Fig. 8 represents a sectional view taken substantially along the line 8-8, Fig. 1.

Fig. 9 represents a perspective View of the thread-case with the latch-lever in raised orreleased position, showing the relatively straight path of travel of the bobbin-thread to the work as the thread emerges from the center thread-eye plan view of the threadused when the bobbin-thread is supplied by a cop.

Fig. 10 represents a disassembled perspective view of the thread-case, illustrating the details of construction of the latching means and the thread-tensioning device.

Referring to' the drawings, the present invention has been embodied in a straight hole buttonhole sewing machine of the type disclosed in the U. S. patent of E. B. Allen et al., No. 1,966,432, dated July 17, 1934. The sewing machine has a vertically reciprocatory and laterally vibratory needle I adapted to penetrate work which is held by an upper work-clamp 2 upon a movable workplate 3 longitudinally slidable on a bed-plate 4 of the machine-frame 5. 'Formed in the bedplate 4 is a needle-aperture 6 elongated in a direction transversely of the line of seam-formation to accommodate the lateral vibrations of the needle I.

Cooperating with the needle I in the formation of lock-stitches is a rotary loop-taker, indicated generally as 1, disposed below the level of the bed-plate 4 and preferably of the rotary hook type. The loop-taker 1 is carried by a horizontally disposed loop-taker shaft 8 having its axis disposed substantially in a vertical plane bisectin the needle aperture 6, the loop-taker I having a cup-shaped body 9 provided at the outer edge'of its periphery with the usual needle-thread loop-seizing beak l0. Formed in the cup-shaped body 9 of the loop-taker 1 is an internal raceway ll (Fig. 3) .of which the outer side wall is provided by adetachable gib l2 secured to the looptaker body by screws I3. I

an opposed shoulder i1 defining therebetween a thread-loop clearance gap. Extending upwardly from the body of the thread-case carrier I4 is a substantially C-shaped rotation-restraining projection or lug it which is adapted to enter between two stop-fingers l9 endwise adjustably secured beneath the bed-plate t, the lug l8 and the stop-fingers I9 cooperating in maintaining the thread-case carrier and thread-case substantially stationary during the rotation of the looptaker. The thread-case carrier is formed at its upper side, and substantially at the base of the rotation-restraining lug ill, with an elongated needle-clearance opening or slot 20, Figs. 3 and 5, affording an inner needle-guide-wall 2i and an outer needle-guide-wall 22, which outer wall is contained in the vertical plane containing the extremities of the vertically spaced limbs of the C-shaped rotation-restraining lug H8. The inner wall 2| prevents deflection of the needle I into the path of the hook-beak Ill. The outer wall 22 guides the needle against deflection away'from the path of the hook-beak l and assists in preventing the needle-thread loop from bowing outwardly on the wrong side of the needle I.

The thread-case carrier I4 is formed in front of the bearing-rib with a substantiall conically shaped guard-flange 23, the base 23 of which flange is somewhat larger in diameter than the bearing-rib ['5 and overlaps, but is spaced slightly from, the gib l2. The guard-flange at its outer end terminates in the outer edge 24, Fig. 4, of the side-wall of the thread-case car'- rier M. The guard flange 23 serves to prevent contact of the front limb of the needle-threadloop with the oiled bearing rib l5 during the loopcasting operation. As shown in Figs. 1, 2 and 4, the conical wall of the guard-flange 23 is formed with a notch or pocket 25 for the reception of the hook-shaped free end 26 of a vibratory opener-arm 2'! carried on a rock-shaft (not shown) which is adapted to be actuated in a manner disclosed in the above mentioned U. S. patent of E. B. Allen et al., No. 1,966,432. As is customary, a mechanical opener of the type just described functions intermittently to turn or oscillate the thread-case carrier in a direction opposite to the direction of rotation of the rotary loop-taker for the purpose of moving the rotation-restraining member out of contact with the stop-fingers, thereby providing an open passageway on each side of the rotation-restraining member for the unobstructed free travel of the needle-thread-loop about the thread-case carrier during stitch-formation.

It will be observed in the drawings that the -Cshaped rotation-restraining member l8 extends forwardly of the vertical plane containing the outer edge 24 of the thread-case carrier l4; To prevent snagging of the needle-thread-loop as it is being expanded about the thread-case on this extended portion of the rotation-restraining member, there is secured by screws 28 on a flat 29, provided adjacent the rotation-restraining lug 18 on the cast-ofi side of the thread case carrier M, a curved sheet-metal plate-member 30 shaped at its lower end to form a continuation or extension of the conical wall of the guard flange 23 and at its upper endv bent so that its outer edge 3| lies in substantially the same vertical plane as the outer surface of the rotationrestl'aining lug l3. It will be seen in Fig. 3, that the outer edge 3| of the plate-member 30 is convexly curved from the edge 24 of the threadcase carrier to the outer surface of the rotationrestraining lug H8. The curved outer edge 3|, in addition to directing the needle-thread-loop about the rotation-restraining lug I8, also serves to absorb some of the thread contained in the needle-loop when the same has been cast off and is being pulled up into stitch-setting position by the action of the usual take-up. In order that the needle-thread-loop cannot become snagged on the sheet-metal plate-member 39, the lower end is bent inwardly so as to project into a small hole 32 formed in the conical wall of the guardflange 23. That portion of the plate-member adjacent the inwardly bent lower end is chamfered ofi to blend in with the conical wall of the guard-flange 23, thereby to present a smooth surface to the needle-thread-loop as it is cast about the thread-case carrier.

Ccmplemental to the thread-case carrier I4 in providing a thread-mass enclosing means for the locking or bobbin-thread supply, is a thread-case 33. The thread-case 33 comprises an outer endwall 3% and an inwardly extending cylindrical flange or skirt-portion 35, which skirt-portion is adapted to be telescopically received within the usual bobbin-receiving circular cavity 36 in the thread-case carrier Hi. There is provided in the center of the end-Wall 34 a hardened insert having extending therethrough a thread-eXit-eye 31 which is utilized to guide the bobbin-thread B when a center-unwind cop is used in the threadcase. When a conventional bobbin is used, the thread B is guided by a thread-exit-eye 38 provided in the cylindrical skirt-portion 35 of the thread-case. To facilitate threading the eye 38, the skirt-portion 35 is formed with an inclined threading-slit 39 opening into the inner edge of the skirt-portion.

The thread-case 33 and the thread-case carrier M are maintained in telescoped relation by means of a latch-member 4i) slidingly disposed in an undercut guicleway ll (Fig. 10) provided in the end-wall 3d of the thread-case. The latch-member 49 is substantially U-shaped with the extremities of the two limbs 42, 43 thereof shouldered to form latch-lugs M, 45 adapted to enter suitable keeper-slots d6, 41 (Fig. 4) provided in the thread-case carrier M. It will be seen in Fig. 10 that the limb 43 of the latch-memher at is preferably reversely bent backwardly and that the latch-lug 45 is provided at the free end of the reversely bent limb. The advantage of this feature is that the latch- lugs 44 and 55 can be more widely spaced apart circumferentially of the thread-case 33, thus making possible the latching of the thread-case to the carrier in a manner such that shaking and tilting of the thread-case is reduced to a minimum. The two 1atch-lugs 44, st are yieldingly maintained in the keeper-slots 455, t? by a coil-spring 38 housed in a spring-receiving hole 49 (Fig. 8) formed in the endwall 3 3 of the thread-case parallel to the guideway M; the free end of the coil-spring 18 bearing against a shoulder 59 formed by the base of the latch-lug lid on the latch-member 43-. To provide for retracting the two latch-lugs 44 and d5 out of their respective keeper-slots, whereby the thread-case can be removed from the thread-case carrier, there is disposed between the two limbs '32 and 23 a latch-retracting cam-arm 5| pivotally supported on a fulcrum-pin 52 fixed in and extending between the two limbs of the latch-member 40. That end of the latch-arm 5| adjacent the fulcrum-pin 52 is formed with a cam-projection 53 which is adapted to extend into a suitably located aperture 54 in the end- Wall 34 of the thread-case 33. At its opposite end, the latch-arm 5| is preferably formed with an enlarged segmental head 55 beneath which the operator may insert his finger-nail and swing the latch-arm outwardly on the fulcrum-pin 52, thus causing the cam-projection 53 to engage the side of the aperture 54 and retract the latch- lugs 44 and 45 out of their respective keeper- slots 46 and 41. Fig. 9 shows the latch-arm 5| in its lugretracting position, and it will be seen from this view that the latch-arm affords convenient means for grasping the thread-case to insert it in the thread-case carrier and to remove it therefrom. To facilitate the latching of the thread-caseto the thread-case carrier, each of the latch- lugs 44 and 45 are chamfered, as at 44' and 45', and the keeper- slots 46 and 41 are chamfered, as at 45' and 41' (Fig. 4). These chamfers on the latch-lugs and keeper-slots cooperate and are in a direction (Fig. 8) such that, after the threadcase 33 is inserted into the thread-case carrier M, a manual pressure against the end-wall 34 of the thread-case in a direction to force the threadcase into the carrier l 4 will cause the latch-member 40 to shift against the action of the spring 48 into retracted position. When the threadcase 33 is properly seated in the thread-case carrier I 4, the latch-lugs snap into the keeper-slots and secure the parts in thread-mass confining relationship. To provide for limiting the retracting movement of the latch-member 40, the limb 42 thereof has threaded into it a stop-screw 56 (Fig. which, in its effective stop-position, contacts the bottom of a clearance slot 51 formed in the end-wall 34 of the thread-case. In addi: tion to serving as a stop, the screw 56 fastens to the latch-member 4!] a leaf-spring extension 58 reversely bent to project through the clearanceslot or -opening 51 and provide a bobbinor copgripping element which functions to hold the bobbin or cop within the thread-case when the same is removed from the thread-case carrier. The leaf-spring extension 58 is so shapedat its free end that when the extension is shifted into its effective gripping position it will engage the periphery of the thread-cop only sufiiciently to prevent the cop from falling out of the threadcase without crushing the cop, even after a major portion of the center of the cop has been unwound. The latch-member 40 and the latchretracting cam-arm 5i are substantially flush with the outer face of the thread-case end-wall 34 when the thread-case is latched to the threadcase carrier, and accordingly the latch-member does not interfere with the passing of the needlethread loop about the thread-case by the looptaker. Moreover, the co-planar arrangement of the latch-member and latch-arm minimizes the required thickness of the thread case end-wall, and thereby affords a maximum of thread-carrying capacity within the thread-case. It will be appreciated that the latching of the thread-case 33 to the thread-case carrier M at two widely spaced points eliminates shaking and tilting of the case relative to the carrier.

After the bobbin-thread emerges from the center eye 3'! or the skirt-eye 38, it is directed to a tensioning device now to be described. Secured, preferably by means of a screw 59, to the endslit 6 wall 34 of the thread-case 33 is a flat L-shaped leaf-spring 60. The upper substantially horizontally disposed limb of the leaf-spring is adapted to bear upon a floating shoe 6| disposed Within an arcuate recess 62 provided in the base-portion of an upstanding C-shaped rotation-restrain ing member 63 extending upwardly from the thread-case and disposed in a vertical channel It formed in the similar C-shapcd rotationrestraining lug S8 of the thread-case carrier M. The shoe 6| is loosely supported at one end upon a positioning-pin 64 (Fig. 10), projecting outwardly from the back wall of the arcuate recess 62 and extending through an enlarged hole 65 in the shoe 6! and a hole 66 in the leaf-spring 50. The shoe 5! at its other end rests on the'bottom of the recess 62. As clearly shown in Fig. 9, the bobbin-thread B, after emerging from the center thread-eye 31, is led to the left of a thread-guiding pin 67, which projects from the face of the floating shoe 6! and through a clearance hole 68 in the leaf-spring member 68, thence between the shoe El and the leaf-spring 5B of the tension device. The degree of tension applied to the thread as it travels through the tension device is adapted to be regulated by a screw 69 (Figs. 6 and 10) threaded through the rotation-restraining member 63, which screw bears against the back of the shoe BI and is accessible for adjustment from behind the member 63. From the tension device, the bobbin-thread is led rearwardly behind a second thread-guiding pin 10 (Fig. 9) disposed in a threading-clearance-recess H and then vertically through a threading-slit '52 formed in the c-shaped rotation-restraining member 53. Secured in a recess 73 provided in the top surface of the rotation-restraining member 63 is a spring-plate 14 (Fig. 9) of which the free end thereof is disposed to maintain the bobbinthread at the inner end of the threading- As previously mentioned, the thread-case which I have invented is adapted equally well to handle a center unwind cop or a conventional bobbin. When using a cop, the latch-arm 5| on the thread-case is grasped and, after drawing a suitable length of thread from the center of the cop, the thread is inserted through the threadexit-eye 31 and past the guide-pin 5?, then laterally to the right for introduction between the leaf-spring 6i! and the shoe 54, after which it is directed behind the guide-pin 11], then through the threading-slit 12 and under the free end of the spring 14. When using a conventional bobbin, the thread is introduced through the inclined threading-slit 39 into the thread-exit-eye 38, thence through a notch 75 (Fig. 10) and about the guide-pin 61, then beneath the leafspring 60, then rearwardly behind the guide-pin 10, then upwardly through the threading-slit 12 and under the free end of the spring 14. It will be understood that the guide-pin 7G and the spring 14 serve to maintain the thread against the inner end of the threading-slit 12 formed in the rotation-restraining member 63 on the threadcase. The bobbin-thread is maintained in this position for cooperation with a thread pull-off member actuated to move in the space defined by the spaced limbs of the rotation-restraining member 63. The thread pull-01f member and its operating mechanism form the subject of my copending application Serial No. 611,724, filed August 21, 1945, and, thereforano further reference thereto will be made in this case.

From the above description and accompanying drawings, it will be appreciated that I have invented a thread-mass enclosing means for a sewing machine loop-taker, which means is adapted to permit employment of either a cop or a conventional bobbin. The thread-case of the thread-mass enclosing means can be readily inserted into the thread-case carrier and also removed therefrom for thread replenishment. The latching expedient devised by me secures the thread-case to the carrier at spaced points, and this is advantageous for the reason that it prevents, to a large extent, shaking of the threadcase relative to its carrier. The elimination of such shake contributes to the more quiet and efficient operation of the loop-taker. The improved tension device of the present invention utilizes a simple flat leaf-spring instead of the more common form of curved spring used heretofore. Obviously, it is easier to manufacture a flat spring of the type I employ than it is to produce a curved spring having a shape coinplemental to the curve of the periphery of the thread-case. Further, the use of a floating shoe opposed to the flat-spring, the shoe being backed up by an adjusting screw, provides a very successful form of tension regulating means.

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

1. A loop-taker for sewing machines, comprising, a circularly moving body-member having a thread-loop seizing beak and a raceway, threadmass enclosing means provided with a bearingrib journaled in said raceway, means for restraining said thread-mass enclosing means against turning movement with said body-member, a, guard-member on said thread-mass enclosing means having a portion thereof of greater diameter than said bearing-rib at the loopcast-off position of said body-member, and a thread-loop absorbing member carried on said thread-mass enclosing means and efiective with said guard-member in controlling the castof thread-loop.

2. A loop-taker for sewing machines, comprising, a circularly moving body-member having a thread-loop seizing beak and a, raceway, threadmass enclosing means provided with a bearingrib journaled in said raceway, means for restraining said thread-mass enclosing means against turning movement with said body-member, a guard-member on said thread-mass enclosing means for preventing the thread-loop from contacting said bearing-rib in the region of the casting off of said thread loop by said body-member, and a thread-loop absorbing member carried by said thread-mass enclosing means and forming an extension of said guard meinber, said guard-member and thread-loop absorbing member cooperating in controlling the cast-off thread-loop 3. A loop-taker for sewing machines, comprising, a circularly moving body-portion having a thread-loop seizing beak and a raceway, threadmass enclosing means providing with a bearingrib journaled in said raceway, means including a projection carried by said thread-mass enclosing means for restraining said enclosing means against turning movement with said body-portion, a guard-member on said thread-mass enclosing means having a thread-loop cast-on wall and a base-portion of greater diameter than said bearing-rib, and a thread-loop absorbing member shaped to form an extension of the cast-on wall of said guard-member and secured to said thread-mass enclosing means adjacent said rotation-restraining projection.

4. A loop-taker for sewing machines, comprising, a circularly moving body-portion having a thread-loop seizing beak and a raceway, threadmass enclosing means provided with a bearingrib journaled in said raceway, means including a projection carried by said thread-mass enclosing means for restraining said enclosing means against turning movement with said body-portion, a guard-member on said thread-mass enclosing means having a thread-loop cast-on wall and a base-portion of greater diameter than said bearing-rib, and a plate-like thread-loop absorbing member carried by said thread-mass enclosing means and shaped to form an extension of the cast-on wall of said guard-member and to provide a curved thread-loop engaging edge effective with the base-portion of said guard-member in controlling the cast-01f thread-loop.

5. A loop-taker for sewing machines, comprising, a circularly moving body-portion having a thread-loop seizing beak and a raceway, threadmass enclosing means provided. with a bearingrib journaled in said raceway, means carried by said thread-mass enclosing means for restraining said enclosing means against turning movement with said body-portion, and a thread-loop absorbing member disposed on the cast-off side or" said thread-mass enclosing means and having a convex thread-loop engaging edge effective for controlling the thread-loop after it is cast off by the body-portion.

6. A loop-taker for sewing machines, comprising, a circularly moving body-portion having a thread-loop seizing beak and a raceway, threadmass enclosing means provided with a bearingrib journaled in said raceway, means inciuding a projection carried by said thread-mass enclosing means for restraining said enclosing means against turning movement with said body-portion, and a blade-like thread-loop absorbing me i.- ber secured to said thread-mass enclosing means adjacent said projection and bent to provide a convex thread-loop-engaging edge spaced from said thread-mass enclosing means in a direction parallel to the axis of movement of said bodymember for effecting a controlling action on the thread-loop following cast off by said bcdy-portion.

7. A loop-taker for sewing machines, comprising, a circularly moving body-portion having a thread-loop seizing beak and a raceway, threadmass enclosing means provided with a bearingrib journaled in said raceway and having a substantially flat front end-wall, means for restraining said thread-mass enclosing means against turning movement with said body-member including a projection carried by said thread-mass enclosing means and having a portion thereof extending forwardly of the front end-wail of said thread-mass enclosing means, and a member carried by said thread-mass enclosing means and having a thread-loop deflecting portion for directing one limb of a cast thread-loop outwardly about said rotation-restraining projection.

8. A loop-taker for sewing machines, comprising, a circularly moving body-portion having a thread-loop seizing beak and a raceway, threadmass enclosing means provided with a bearingrib journaled in said raceway and having a. substantially flat front end-wall, means for restraining said thread-mass enclosing means against turning movement with said body-member including a projection carried by said thread-mass Q9 enclosing means and having a portion thereof terminating in a face contained in a plane spaced forwardly of the front end-wall of said threadmass enclosing means, and a plate-like member secured to said thread-mass enclosing means and having a thread-loop-deflecting edge beginning substantially at the front end-wall of said thread-mass enclosing means and terminating in the plane containing the face of said projection.

9. A thread-carrier for sewing machine 10op-.

takers, comprising, a cupped body having one end-wall and a side-wall, said side-wall being provided with a circumferential bearing-rib and with a needle-clearance slot at one side of said bearing-rib, a portion of said side wall at the same side of said bearing-rib as the needle-clearance slot being oonically convergent away from said bearing-rib to form a. cast-on guard-flange having its base spaced from and extending radially outwardly beyond said bearing-rib, and said side wall being provided with a thread-loop absorbing member forming a conical guard-flange continuation increasing in' depth in a direction away from the end-wall of said thread-carrier.

10. Thread-mass enclosing means for sewing machine loop-takers, comprising a thread-case and a carrier therefor, a single latch-member carried by said thread-case and having spaced limbs each provided with a latch-lug, a plurality of keeper-apertures in said carrier, means for maintaining said latch-lugs in engagement with said keeper-apertures, and a single manually operated means disposed between the limbs of said latch-member for effectin a withdrawal of said latch-lugs from said keeper-apertures.

11. Thread-mass enclosing means for sewing machine loop-takers, comprising a thread-case and a carrier therefor, a single U-shaped latchmember carried by said thread-case and having a latch-lug provided on each limb of said latchmember, a plurality of keeper-apertures in said carrier, means for maintaining said latch-lugs in engaging relation with said keeper-apertures,

and a single manually operated means disposed in the space between the limbs of said U-shaped latch-member for effecting disengagement of said latch-lugs from said keeper-apertures.

12. Thread-'mass enclosing' means for sewing machine loop-takers, comprising a carrier-member provided with a plurality of keeper-apertures, a thread-case adapted to be associated with said carrier-member in thread-mass enclosing relation and having an end wall, a single latch-member slidably disposed in said end Wall and having spaced limbs each provided with a latch-lug for engagement with said keeper-apertures, and an operating lever for said latch-member located between the limbs of said latch-member and disposed substantially flush with the outer surface of said latch-memberin the keeperaperture engaging positions of said latch-lugs.

13. Thread-mass enclosing means for sewing machine loop-takers, comprising a carrier-member provided with a plurality of keeper-apertures, a thread-case adapted to be associated with said carrier-member in thread-mass enclosing rela.. tion and having an end wall, a single latch-member slidably disposed in said end wall and having spaced limbs each provided with a latch-lug, spring means housed within said thread-case end-wall for yieldingly urging said latch-lugs into said keeper-apertures, and an operating lever for said latch-member located between the limbs of said latch-member for retracting said latch-lugs from said keeper-apertures.

l4. Thread-mass enclosing means for sewing 10 machine loop-takers, comprising a carrier-mem ber provided with a plurality of keeper-apertures, a thread-case adapted to be associated with said carrier-member in thread-mass enclosing relation and having an end-wall, a single latch-member slidably disposed in said endwall and having spaced limbs each provided with a latch-lug, a spring housed within said threadcase end-wall in parallel relation with the direction of sliding movement of said latch-member for yieldingly urging said latch-lugs into said keeper-apertures, and an operating lever pivoted to said latch-member between the spaced limbs thereof and actuable for retracting said latchlugs fromsaid keeper-apertures.

15. Thread-mass enclosing means for sewing machine loop-takers, comprising a carrier-member provided with a plurality of keeper-apertures, a thread-case adapted to be associated with said carrier-member in thread-mass enclosing relation and having an end-wall, a U-shaped latchmember slidably disposed in said end-wall substantially flush with the outer face of said endwall, latch-lugs provided on the limbs of said U-shaped latch-member, a spring housed within said thread-case end-wall for yieldingly urging said latch-lugs into said keeper-apertures, and an operating lever for said latch-member located between the limbs of said latch-member and disposed substantially flush with the outer surface of said thread-case end-wall in the keep er-aperture engaging positions of said latch-lugs.

16. Thread-mass enclosing means for sewing 'machine loop-takers, comprising a carrier-member provided with at least one keeper-aperture, a removable thread-case adapted to be associated with said carrier-member in thread-mass enclosing relation, latching means carried by said thread-case and having a latch-lug adapted to enter said keeper-aperture, manually operable means for shifting said latch-lug into a retracted position and out of engagement with said keeperaperture, whereby the thread-case can be removed from its carrier, and a resilient member carried by said latching means and movable into engagement with the thread-mass in said threadcase when said latch-lug is shifted into retracted position to retain the thread-mass within the thread-case when the latter is removed from its carrier-member.

17. Thread-mass enclosing means for sewing machine loop-takers, comprising a carrier-member provided with at least one keeper-aperture, a removable thread-case adapted to be associated with said carrier-member in thread-mass enclosing relation, latching means carried by said thread-case and having a latch-lug adapted to enter said keeper-aperture, manually operable means for shifting said latch-lug into a retracted position and out of engagement with said keeperaperture, whereby the thread-case can be refmoved from its carrier, and a leaf-spring member carried by said latching means and positioned to move into engagement with the thread-mass within the thread-case when said latch-lug is shifted into retracted position.

18. Thread-mass enclosing means for sewing machine loop-takers, comprising a carrier-member provided with at least one keeper-aperture,

a removable thread-case adapted to be associated with said carrier-member in thread-mass enclosing relation and having a clearance opening therein, latching means slidably disposed on said thread-case and having a latch-lug adapted to enter said keeper-aperture, manually operable means for shifting said latch-lug into a retracted position and out of engagement with said keeperaperture, and a leaf -spring carried by said latching means and having its free end positioned to move through said clearance opening and into engagement with the thread-mass within the thread-case when said latch-lug is shifted into retracted position.

19. A thread-mass enclosing means for sewing machine loop-takers, comprising a carrier-memher provided with a plurality of keeper-apertures,

a thread-case adapted to be associated with said carrier-member in thread-mass enclosing relation and having an end-wall, a single U-shaped latch-member slidably disposed in said end-wall and having one of its limbs reversely bent to increase the space between the free ends of the limbs, a latch-lug formed on the end of each limb, spring means for yieldingly urging said latch-lugs into said keeper-apertures, and an operating lever for said latch-member located between the limbs of said latch-member for retracting said latchlugs from said keeper-apertures.

20. A loop-taker for sewing machines, comprising, a circularly moving body-portion having a thread-loop seizing beak, a thread-mass enclosing means journaled in said body-portion and restrained against rotation therewith, and thread-tensioning means including a flat leafspring secured to said thread-mass enclosing means, and a member opposed to said leaf-spring and supported on said thread-mass enclosing means for free floating movement.

21. A loop-taker for sewing machines, comprising, a circularly moving body-portion having a thread-loop seizing beak, a thread-mass enclosing means journaled in said body-portion and restrained against rotation therewith, and thread-tensioning means including a fiat leafspring secured to said thread-mass enclosing means, a member opposed-to said leaf-spring and supported on said thread-mass enclosing means for floating movement, and means associated with said floating member for regulating the tension applied'to a thread passing between said spring and said floating member.

22. A thread-case for sewing machine looptakers, comprising a body-portion provided with a recess and having a substantially fiat end-Wall, a member supported on said thread-case forfloat- 0 ing movement and disposed in said recess with its outer face substantially flush with the outer surface or saidflat end-wall, and a thread-tension leaf-spring secured to said flat end-wall and having a'portion thereof opposed to said floating member;

23. A thread-case for sewing machine looptakers, comprising a cylindrical body-portion, a member extending substantially radially beyond the periphery of said body-portion and having a 0 recess formed therein, a free floatingmember disposed in said recess, and a thread-tension'leafher disposed in said leaf-spring secured to spring carried by said thread-case and having a portion thereof opposed to said floating member.

24. A thread-case for sewing machine looptakers, comprising a cylindrical body-portion having an end-wall, a member projecting beyond the periphery of said body-portion and having a recess formed therein, a free floating member disposed in said recess with its outer face substantially flush with the end-wall of said thread-case, and a thread-tension leaf-spring carried by Said thread-case and having a portion thereof opposed to said floating member.

25. A thread-case for sewing machine looptakers, comprising a cylindrical body-portion having an end-wall, a member projecting beyond the periphery of said body-portion and having a recess formed therein, a free floating member disposed in said recess with its outer face substantially flush with the end-wall of said thread-case, a thread-tension leaf-spring carried by said thread-case and having a portion thereof opposed to said floating member, and an adjustin screw engageable with said floating member for regulating the tension applied to a thread passing between said leaf-spring and said floating member.

26. A thread-case for sewing machine looptakers, comprising a body-portion, a supporting pin projecting from said body-portion, a member supported on said pin for limited universal movement, a thread-tension leaf-spring secured to said body-portion and having a part thereof opposed to said member, and means for regulating the amount of tension applied by said leaf-spring to a thread passing between said leaf-spring and said member.

27. A thread-case for sewing machine looptakers, comprising a body-portion, a member mounted on said body-portion for limited universal movement, a thread-tension leaf-spring secured to said body-portion and having a part thereof disposed in thread-engaging relation with said member, means for regulating the tension adapted to be applied by said leaf-spring, and a thread-guiding pin extending from the threadengaging face of said member for properly directing the thread between said leaf-spring and said member.

28. A thread-case for sewing machine looptakers, comprising a "body-portion having a recess formed "therein, a supporting pin projecting from the bottom of said recess, anelongated memrecess and supported on said pin for limited universal movemenuan L-shaped said body-portion and disposed so that one of its limbs is opposed to and extends'in the direction of length of said member, and a screw threaded into said body-portion and engageable with said member for regulating the tension applied to'a'thread passing between the leaf -spring and the member.

ALFRED 'R. WOOD.

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