US2236830A

US2236830A - Loop-taker mechanism for sewing machines

Info

Publication number: US2236830A
Application number: US299415A
Authority: US
Inventors: Myers Walter
Original assignee: Singer Co
Current assignee: Singer Co
Priority date: 1939-10-14
Filing date: 1939-10-14
Publication date: 1941-04-01
Anticipated expiration: 1958-04-01
Also published as: FR868738A; GB534003A; DE748861C

Description

April 1, 1941. w. MYERS 2,236,830

LOOP-TAKER MECHANISM FOR SEWING MACHINES Filed Oct. 14, 1939 I 3 Sheets-Shet 1 ljalter J/l yers 4, a 8 MW W. MYERS April 1, 1941.

LOOP-TAKER MECHANISM FOR SEWING MACHINES 3 Sheets-Sheet 2 Filed Oct. 14, 1939 W. MYERS April 1, 1941.

LOOP-BAKER MECHANISM FOR SEWING MACHINES Filed Oct. 14, 1939 3 Sheets-Sheet 3 TJQ @N Patented Apr. 1, 1941 LOOP-TAKER MECHANISM FOR SEWING MACHINES Walter Myers, Bridgeport, Conn., assignor to The Singer Manufacturing Company, N. J., a corporation of New Jersey Elizabeth,

Application October 14, 1939, Serial No. 299,415

12 Claims.

This invention relates to loop-taker mechanisms for sewing machines and more particu larly to loop-taker mechanisms of the verticalaxis rotary hook type in which a bobbin-carrier is journaled in and restrained against rotation with the rotary hook.

A primary object of the invention is to provide bobbin-carrier rotation restraining means which will facilitate casting of needle-thread loops about the bobbin-carrier by the rotary hook and permit of operation of the sewing machine at high speeds.

A further object of the invention is to provide a rotary-hook mechanism assembly adapted to be detachably secured as a unit to a sewing machine and including improved bobbin-carrier rotation restraining means.

With these and other objects in view, as will hereinafter appear, the invention consists in the loop-taker mechanism described in connection with the accompanying drawings which illustrate a. preferred embodiment of the invention and in which:'

Fig. 1 represents a vertical section of the looptaker end portion of the bed-plate of a twoneedle sewing machine containing the present improvements, the left hand loop-taker mechanism being shown in vertical section and the right hand loop-taker mechanism mainly in front elevation. Fig. 2 is a bottom plan view and Fig. 3 a top plan view of the same portionof the machine, the throat-plate and side slideplan view of the loop-taker mechanism supporting bracket, and Fig. 5 represents a vertical section of said bracket substantially on the line 55 of Fig. 4. Figs. 6 and 7 represent different perspective views of the bobbin-carrier. is an enlarged vertical section of portions of one of the loop-takers and its bobbincarrier, the section being taken substantially on the line 8-8 of Fig. 3.

The sewing machine shown in the drawings has a work-supporting bed-plate I provided with the usual-side slide-plates 2 and 3, front slideplate 4 and throat-plate 5.

Operating through suitable feed-slots in the throat-plate 5 is a feed-dog 5 carried by a feedbar 1 deriving work-advancing movements from a horizontally disposed feed-advance rock-shaft Fig.8'

plates being removed'in Fig. 3. Fig. 4 is atop secured by screws I4. The bushing-aperture in the bearing-lug I3 is larger than the bushingperture in the bearing-lug l2 and the bushing I'll is correspondingly larger than the bushing 9 to accommodate the rock-shaft 8 of uniform diameter. The shaft-bearing arrangement described facilitates manufacture and particularly when it is desired to provide several alined shaftbearings, the split-bushings providing for taking up wear.

The feed-bar I has at its rearward end a fork I engaged by an eccentric [5 carried by a horizontally disposed rotary shaft l6 journaled in bushings l1 and I8 which are respectively secured in bearing-lugs l9 and 20 depending from the bed-plate I.

\ The feed-dog 6 has needle-apertures 2| to receive the two needles 22 carried by a needle-bar 23, said needle-bar being actuated by means oi needle-reciprocating and vibrating mechanism (not shown) which, in the present machine, is substantially the same as that disclosed in my prior'U. S. Patent No. 2,128,031, Aug. 23, 1938. Opposed to the feed-dog 6 is the usual springdepressed presser-foot 24.

Complemental to the.needles 22 in the forma tion of lock-stitches are two corresponding 1oop-' takers of the vertical-axis rotary hook type disposed at opposite sides of the feed-bar 1. Each of the loop-taker mechanisms'including threadcase rotation restraining means, is assembled as a.complete unit in a supporting-

bracket

25 or 26 commercially known as a hook-saddle. Each bracket 25 or- 26 has a rearwardly extending split bracket 26 being clamped upon the bushing l8.

Each supportlng-

bracket

25 or 26 also has a forwardly extending and slotted lug 29 adjustably secured by a screw 38 to a rib 3| at the under side of the bed-plate I. As'the loop-taker mechanisms of the two supporting-brackets are the same the description of one will suflice.

The supporting bracket 25 has vertically spaced bearing-

lugs

32 and 33, provided with vertically

alined apertures

34 and 35, the lower portions of which apertures are threaded. Disposed in the upper unthreaded portions of the

apertures

34 and 35 are ball-

bearings

36 and 31 which are vertically located in said apertures by bushings 38 and 39 threaded into the

lugs

32 and 33, respectively, from the under sides of said lugs.

that the hook-shaft rotates twice for eachJ rotation of the actuating shaft 55.

I The rotary-hook shaft 40 has a longitudinal bore 43 enlarged at the lower end of said shaft to receive the reduced stem of an eccentric 56 disposed below the supporting bracket 25. The

eccentric 4% is secured for rotation with the hook-shaft Qt, by means of a pin 65 extending transversely through the stem of the eccentric it and entering suitable notches in the lower end of the hook-shaft. Threaded intothe upper end of the'stem of the eccentric is an elongated screw E6 extending downwardly through the bore d3 of the hook-shaft and serving to hold the hook-shaft and the eccentric 4% in assembled relationship.

Integral with the upper end of the hook-shaft 60 is the cup-shaped'body of a rotary hook ti, and interposed between the bottom wall of said rotary hook and the upper ball-bearing 36 is a shouldered washer 48 providing at the under side thereof a recess 'in which is disposed a washer 69 of felt or other similar material and overlying the race-rings of the ball-bearing 35. Similar washers, indicated i'n'the drawings by the same reference characters, are interposed between the hook-shaft gear 40 and the lower ball-bearing 31. While the rotary hook 41 is, in the present case, integral with the hook-shaft fit, 'it will of course be understood that the rotary-hook may comprise a separate body secured to the hook-shaft in any usual manner, or it may be secured to the hookshaft by the screw 45.

The side wall of the cup-shaped body of the rotary hook M is partly cut 'away to provide a loop-seizing beak 50, and a needle-guard memher 5! is detachably secured upon the side wall of the rotary hook to extend across the gap of said cutaway portion and under the beak of the hook.

The inner face of the hook-body, within the rim thereof, is shouldered to provide a bobbincarrier raceway comprising a vertically cylindrical bearing wall 52 and an inwardly extending bearing ledge 53. Journaled in-said raceway is an interrupted bearing-rib 54 of a bobbincarrier 55, said bearing-rib 55 being retained in thehookqaceway by a gib 56 secured by screws 51 upon the hook-rim. The gib is shaped substantially the same as that more fully disclosed in my-prior U. S. Patent No. 1,917,771, July 11, 1933, although it is preferably made in two endto-end abutting sections. One end of the interrupted bearing-rib 54 of the bobbin-carrier provides an inclined thread-loop detaining shoulder 58.

The bobbin-carrier 55 has an interrupted peripheral flange 59 overhanging the hook-gib 56, which flange has a beveled or inclined portion 59' at the thread-loop cast-on side of the bobbincarrier directly above the end portion of the bearing-rib 5% which terminates in .the shoulder 58. Adjacent its opposite end, the flange 59 of the bobbin-carrier is provided with an upwardly open segmental oil-pocket 60 preferably containing an oil-absorbent material 6L. As shown in Fig. 8 of the drawings, the bottom wall of the oil-pocket 60 is connected by a vertical duct 62 in the side wall of the bobbin-carrier with a radial duct B3 til) aaeaeac terminating in the outer face of the bearing-rib 54, thereby providing means for supplying lubricant to the thread-carrier raceway.

The bobbin-carrier flange 59 is partly cut away in the portion thereof substantially opposite to the bearing-rib and flange gaps to provide a shouldered recess 6%. Secured by screws 65 to p the outer face of the vertical side wall of the recess 68 is a bobbin-thread tension-spring 66 bearing against said side wall between two thread-slits G1 and 68 in the bobbin-carrier side wall. The bobbin-carrier 55; has the usual bobbin-post 6Q rising from the bobbin-carrier bottom wall, and pivoted to said post 89 is, the usual spring-pressed latch-member it having its free end adapted to enter a recess H in the rim of the bobbin-carrier 55, whereby the latch member H3 in its closed or bobbin-retaining position is'flush with the rim of the bobbin-carrier. sub

stantially opposite to the latch-recess H, the

inner edge of the bobbin-carrier rim is partly cut away to provide a finger-notch i2 facilitating removal of, the bobbin 13 when the latch-member 70 has been opened.

When threading the bobbin-carrier, the bobbinthread is passed outwardly from the bobbin 13 through the thread-slit 67, under the tension-- spring 6'6, and inwardly through the thread-slit 68, from which the bobbin-thread then passes across the upper flange of the bobbin '83 to the needle-aperture 2! in the feed-dog 6.

The bobbin-carrier 55 is restrained against rotation with the rotary hook 51 by an escapement device permitting free passage of the needlethread loops about the bobbin-carrier. To this end, the bobbin-carrier flange 59 is provided at substantially diametrically opposite sides of the bobbin-carrier with two horizontally arcuate apertures It adapted to be entered by opposed and horizontally arcuate fingers of a rocking escapement-yoke 16. The escapement-finger receiving apertures M. of the bobbin-carrier flange aperture 8] of a bushing 82 adjustably secured by a set-screw 83 in a vertical aperture 84 providedin the supporting-bracket 25. The head 19 of the rock-shaft is smaller in diameter than the bracket-aperture 8t and rests upon the upper end of the bushing 82. As the bushing 82 terminates below the upper end of the bracketaperture 88, the latter thereby provides ancilrecess above the bushing 82. The squared lower end 82' of the bushing82 extends slightly below the supporting-bracket.25, whereby the bushing 82 may be turned to properly position the escapement-flngers i5 with respect to the bobbin-carrier escapement-apertures 14.

The escapement rock-shaft 80 extends below the bushing 82,'and clamped to the lower end of said rock-shaft by a screw 85 is the split hub of a horizontally disposed crank-arm 86. The crankarm- 86 is forked at its free end to embrace the eccentric 66 secured for rotation with the hookshaft at. It will therefore be understood tha thread loops about the bobbin-carrier.

Detachably secured by screws 81 to the flattened lower face of each supporting-

bracket

25 or 25, is a casing 88 which houses the hookshaft eccentric and the crank-arm actuated thereby, said casing also functioning to collect lubricant escaping from the lower hook-shaft bearing and from the escapement rock-shaft, whereby the actuating mechanism housed by said casing is adequately lubricated.

As illustrated in Figs. 4 and 5 of the drawings, the supporting-bracket 26 has a vertical oil-well aperture 89 disposed adjacent the bracket-

lugs

32, 33, and the upper face of said bracket is provided with oil-conducting grooves 98 and 9|. The groove 90 connects the upper end of the oil- ,well 89 and the felt-washer 49 overlying the upper ball-bearing 36, and the groove 9| connectsthe oil-well 89 and the bracket-aperture 84 above same manner with means for lubricating the, hook-shaft and the escapement rock-shaft journaled therein.

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

1. Stitch-forming mechanism for sewing machines comprising, a vertically reciprocatory needle, a vertical-axis rotary hook having a bobbin-carrier raceway, a bobbin-carrier having a bearing-rib joumaled about which bobbin-carrier the needle-thread loops are cast by said rotary hook, said bobbincarrier having a flange overhanging saidbearing-rib and provided at opposite sides of the bobbin-carrier within the thickness of said flange with substantially horizontal and upwardly closed escapement-apertures, a vertical-axis yoke having escapement-fingers adapted alternately to enter the respective escapement-apertures of the bobbin-carrier flange, and means for actuating said yoke in timed relation with respect to the rotation of the rotary hook to provide a free passage for the needle-thread loops.

2. Stitch-forming mechanism for sewing machines comprising, a vertically reciprocatory needle, a rotary hook having a bobbin-carrier raceway, a vertically disposed rotary-hook carrying shaft, means for rotating said shaft, a bobbin-carrier joumaled in said raceway and provided in opposite sides thereof with substantially horizontal escapement-apertures, said bobbin-carrier having an upper rim presenting a smooth and unbroken surface above said apertures, a vertical-axis rock-shaft disposed adjacent to said hook-shaft, a yoke carried by the upper end of said rock-shaft and having escapementfingers adapted alternately to enter the respective escapement-apertures of the bobbin-carrier, an eccentric carried by the lower end of said rotary hook-shaft, and a crank-arm extending in said raceway and from said rock-shaft and having a fork engaging said eccentric.

3. A rotary-hook mechanism assembly adapted to be detachably secured as a unit to a sewing machine, comprising, a supporting bracket having spaced bearing-lugs, a rotary-hook shaft journaled in said bearing-lugs, a spiral-gear carried by said hook-shaft between said bearinglugs, a rotary hook carried by said hook shaft,

a bobbin-carrier joumaled in said rotary hook and provided with a pair of escapement-apertures, an escapement yoke supported by said bracket for rocking movements about an axis substantially parallel to the axis of rotation of said hook-shaft, said yoke having escapement-fingers adapted alternately to enter the respective escapement-apertures of the bobbincarrier, and means operatively connected to said hook-shaft for actuating said escapement-yoke. 4. A rotary-hook mechanism assembly adapted to be detachably securedas a unit to a sewing machine, comprising, a supporting bracket, a rotary-hook shaft joumaled in said bracket, a spiral-gear carried by said hook-shaft, a rotary hook carried by one end of said shaft, an eccentric carried by the other end of said shaft, a bobbin-carrier journaledin said rotary hook and provided with a pair of escapement-apertures, a rock-shaft joumaled in said bracket and disposed substantially parallel to said rotary-hookshaft, a yoke carried by one end of said rockshaft and having escapement-fingers adapted alternately to enter the respective escapementapertures of said bobbin-carrier, a crank-arm extending from said rock-shaft and having a fork engaging said eccentric, and a casing detachably secured to said supporting bracket and housing said eccentric and crank-arm. 5. A rotary-hook mechanism assembly adapte to be detachably secured as a unit to the frame of a sewing machine, comprising, a supporting bracket having spaced bearing-lugs, a rotaryhook shaft joumaled in said bearing-lugs, a gear-wheel carried by said hook-shaft between said bearing-lugs, a rotary hook carried by said hook-shaft at one side of said bracket, an eccentric carried by said hook-shaft at the opposite side of said bracket, a bobbin-carrier joumaled in said rotary hook, a rock-shaft journaled in said bracket and disposed substantially parallel to said hook-shaft, an escapement-yoke carried by one end of said rock-shaft and providing e scapement-fingers adapted alternately to engage. said bobbin-carrier for restraining the bobbin-carrier against. rotation with said rotary hook, a crank-arm extending from the other end of said rock-shaft and in operative engagement with said eccentric for actuating said rock-shaft, and a casing detachably secured to said supporting bracket and housing said eccentric and crank-arm.

6. A rotary-hook mechanism assembly adapted to he detachably secured as a unit to a sewing machine, comprising, a supporting bracket, a rotary-hook shaft joumaled in said bracket, 9. gearwheel carried by said shaft, a rotary hook carried by said shaft atone side of said bracket, an escapement-actuating eccentric carried 'by said ment-fingers adapted alternately to engage said bobbin-carrier for restraining the bobbin-carrier yoke.

against rotation with said rotary hook, a crankarm carried by said rock-shaft and in operative engagement with said eccentric for actuating said rock-shaft, and a casing detachably secured to said supporting bracket and housing said eccentric and crank-arm.

7. A rotary-hook mechanism assembly adapted to be detachably secured as a unit to a sewing machine, comprising, a supporting bracket, a

rotary-hook shaft journaied in saidbracket, a

gear-wheel carried by said shaft, a rotary hook carried by said shaft, a bobbin-carrier joumaled in said rotary book, a rocking yoke having escapement-tlngers adapted alternately to engage said bobbin-carrier for restraining the bobbincarrier against rotation with said rotary hook, means for rocking said yoke, and means providing for lateral adjustment of the rocking axis of sai 8. A rotary-hook mechanism assembly adapted to be detachably secured as a unit 'to a sewing machine, comprising, a supporting bracket, a rotary-hook shaft journaled in said bracket, a 1'0- tary hook carried by said shaft, a bobbin-carrier journaled in said rotary hook, an eccentrlcally apertured bushing secured in said bracket for turning adjustment, a rock-shaft journaled in the eccentric aperture of said'bushing, a yoke carried by said rock-shaft and having escapement-fingers adapted alternately to engage said bobbin-carrier for restraining the bobbin-carrier against rotation with said rotary hook, and operative connections with said rotary-hook shaft assasao chines comprising, a reciprocatory needle, a'ro tal'y 1100!! having a bobbin-carrier raceway, a rotary hook carrying shaft, a bobbin-carrier journaled in said raceway and about which bobbincarrier the needle-thread loops are cast by said rotary hook, a rock-shaft disposed substantially parallel .to said rotary-hook shaft, a bushing having an eccentric-aperture in which said rockshaft is journaled, means providing for turning adjustment of said bushing about its longitudinal axis, a yoke carried by said rock-shaft and having escapement-fingers adapted alternately to enbin-carrier journaled in said rotary hook, a bushgage said bobbin-carrier for restraining the bobbin-carrier against rotation with said rotary hook, and operative connections with said rotary hook shaft for actuating said rock-shaft.

11. Stitch-forming mechanism for sewing machines comprising, a vertically reciprocatory nee die, a vertical-axis rotary-hook shaft, vertically spaced hearings in which said shaft is rotatably journaled, a spiral gear carried by said shaft between said bearings, a horizontally disposed rotary-hook actuating shaft, a spiral gear carried by said rotary-hook actuating shaft and in driving engagement'with the spiral gear carried by said rotary-hook shaft, va rotary hook carried by the upper end of said rotary-hook shaft and provided with a bobbin-carrier raceway, a bobbincarrier journaled in said raceway, a vertical-axis rock-shaft disposed adjacent to said hook-shaft, a yoke carried by the upper end of said rockshaft and having escapement-flngers adapted a1- ternately to engage said bobbin-carrier for restraining the bobbin-carrier against rotation with the rotary hook, an eccentric carried by the lower end of said rotary-hook shaft, and means actuated by said eccentric for rocking said rockshaft. g

12. A loop-taker mechanism for sewing machines, comprising, a vertically disposed and tubular rotary-hook shaft, a rotarymook carried by the upper end of said shaft and provided with a bobbin-carrier raceway, a bobbin-carrier journaled in said raceway, an eccentric having a stem extending into "the bore of said shaft from the lower end thereof, a screw extending downwardly through an aperture in the bottom wall of said rotary hook and threaded into said stem of the eccentric, means for securing said \eccentric against rotation relatively to said hook-shaft, and bobbin-carrier controlling mechanism actuated by said eccentric.

' WALTER MYERS.