US2494006A - Clutch mechanism for sewing machines - Google Patents

Description

Jan. l0, 1950 E. scHolJ CLUTCH MECHANISM FCR SEWING MACHINES 3 Sh'eets-Sheet l Filed Oct. 1, 1946 Jan. 10, 1950 E. scHolJ 2,494,006

CLUTCH MECHANISM FCR SEWING MACHINES Filed Cot. 1, 194e s sheets-sheet 2 IEW/MII@ V 4,

`Fan. l0, 1950 E. scHolJ CLUTCH MECHANISM FCR sEwINC MACHINES 3 SheetsfSheeb 3 Filed OCT.. l, 1946 wuemlov @w MC1" mm @Fla BARRCL wlrH ECCENTRICITY uP RRE/L wm-l accENTmCnTY DowN Patented Jan. 10,3195() CLUTCH MECHANIsMFoR SEWING MACHINES Edgar Schoij, Chicago, Ill., assigner to Union Special Machine Company, Chicago, Ill.,'a corporation of Illinois Application octeber 1, 1946, serial No.' vomito The invention relates to new and useful improvements in a clutch mechanism of the barrel type for imparting intermittent movements to the 'feeding mechanism of a sewing machine.

An object of the invention is to provide an intermittently operating clutch mechanism of lthe above type wherein the gripping surface fof the clutch barrel is eccentric to its axis of rotation so that theV gripping line between the roller and the clutch block shifts back and forth on the clutch block for each rotation of the shaft and wherein the gripping face i the clutch block is so shaped that the wedge angle between the clutch barrel and the clutch block remains sub'- stantially constant as the gripping lines shift. i A further object of the invention is to provide a clutch mechanism of the above type wherein means is provided for changing the eccentricity of the clutch barrel so that the area over which the grip shifts may be increased or decreased to further distribute the wear and increase the life and efficiency of the clutch.

lThese and other objects will in part be obvious and will in part be hereinafter more fully stated.

In the drawings which show the invention as applied to a cup feed type of sewing machine,

Figure l is a View partly in side elevation with parts broken away to show some of the inner mechanism and with parts in vertical section,

Figure 2 is a vertical sectional View through a portion of the machine and showing the means whereby access may be had to the clutch mechanism for varying the eccentricity of the setting of the clutch barrel on the actuated feed shaft,

Figure 3 is a front view of a portion of the housing for the clutch mechanism showing the cap screw removed from the opening and the indicia on the clutch barrel for indicating the relative amount of eccentricity,

Figure 4 vis an enlarged sectional View through the clutch mechanism, the section being taken on line iof Figure l,

Figure 5 is a section on line 5 5 of Figure 4,

Figure 5 is a sectional View taken on the line 6 5 of Figure 4,

Figure is a sectional View taken on the line 'I-'i of Figure 4,

Figure 8 is a' sectional view on the line 8--8 of Figure fi,

^ Figure 9'is a diagrammatic view showing the f 7 Claims. (Cl'. 'I4- 144) in f '2 angle between theinnei surfaceof'the clutc Ybarrel and the gripping-surface of the clutch block is substantially 'equal for eachincremen't of rotation of thev clutch' barrel, n

Figure 10 isa diagrammatic view showing the shifting ofthe setting of 'theclutch barrel'from zero where the inner surface of the clutch barrel is concentric tothe axis'of the actuated shaft to maximum eccentricity 'of the clutch barrel relative to the axis of said shaft. f

While the clutch mechanism embodying the improvements' may be used for many purposes, it is particularly'designed Afor use in connection with the feeding mechanis'mfo'fasewingmachine whereinI the fabric# is 'advanced to the stitching mechanism :by 'an'in'termittently rotated part. The machinefillustratedin the drawings is a cup feed machine of the type shown in the patent granted'EdgarSchoij October 10, 1944, No. 2,360,075. Briefly, the machine` includes a 'housing orv frame Iin Whichis mounted the main 'actuating shaft`2; -`Said housing is provided with an overhanging portion 3xsupporting: an inner feed cup 4 andan outer feedv cup 5 between which the fabric; sections are gripped and fed through the stitching -mechanism. The stitch ing' mechanismv includes a needlev' which is'Y 'carriedby a needlefbarreciprocated bysuitable mechanism `from-the main vshaft 2. 'Cooperating with the needlei Iis a thread {carrying looper'I which moves into the needle threa'df loop at one *sideA of the'fabric and' then `positions' itself at the other side 'off1'the"-fabric.V The looperis carried byafsupporting bar-Which is actuated by suitablemechanism from the-main shaft 2. Cooperating with theloopen'l is a loop carrier or spreader 8 which engagesr the-looper thread loop and positions it for' theneedle to enter prior to penetrating the fabric sections. This spreader 8l is carried by aspreader bar which is actuated by suitable mechanism lfrom thev main shaft 2.

The feed cup 4 is carried by a shaft!) mounted for rotation in a sleeve I0 which in turn is fixed to the frame lofthe machine. -The feed cup 5 is carried by a shaft-II which is connected through a universal'joint with a'shaft I2 mounted in a suitable bearing inV the `-overhanging arm 3. At the upper end of the shaft 9 there is a -gear wheel I3 'carried-'by 'ahub I4 which is secured to a flat section I5y onthe actuated shaft by means of a set screw I6.` Thegear I3 meshes with agear I1 on the shaft I2v and thusrotationsv imparted to the shaft '9 arealsof-impalrted'to the'shaft II; thereby the feed cups are operated in unison and ,turned incrementi'byf'increment for'feeding the fabric to the stitching mechanism. Therpurpose parts, one of which is the actuating part for turn- Y ing the shaft 9, and the other is the holding 'or braking clutch for holding the shaft when turned moved in a clockwise direction and releasing the to a set position and preventing retrograded.

movements thereof as the actuating clutch is returned for a new grip.Y These atwo parts :are simi# lar in construction and a detailed descrtptioniof one will answer for the other. The clutch mechanism includes a sleeve I8 to whichtheclutch -bar. Y

rel I9 of the actuating clutch part is integrally connected. The clutch barrel 20 of the Vbraking clutch is also integrally connected with this sleeve. n theA actuating isha-ft .9 is fa -fhub -2| .which is cylindrical :buteccentrically set rela-tive 'tothe -axis or eenter'of thefshaft `9. This hub vis provided with a flat portionA 22 vandthe sleeve i8 .-isfsecuredto this .fiat portionby arsetA screw 23. Asshown in Figure -8 ,:there:are three 4set screws, one of 4which is' indicated at: 23;', another at 24, and another-at 25.. By loosening the set screws, the sleeve may be adjusted on this eccentric ihub so as to position any one of the three set screws directly over theflat section. isfor the pur- :pose of 'changing `theeccentric#setting of the clutchbarrels' on thek shaft y9,1'as ywill be more fully Aexplained hereinafter:

Mounted 'for free .rotation chitchplatea; This clutchplatefcarries on'its runder `face fa clutch block E26. The :clutch block :2E istrigidlyisecuredto the clutch plate by suita- Y lls'ilezscrews 21; 'Therclutch barrel t9. projects -upwardly :fromfthe sleeve I 8 fand Vthe lc'lu'tcl'i'blocl':

entends l'doxmmzaitdly ,from the 'clutch iplate i25a and the vouterrfacefofthe clutch block isiopposed to 'the :innery vface sof the mclutch barrel. The vclutch block has :three :wedging "faces which vare all similar Vin shape and :are:numberedV28;` 'Dis- 1 posed between each operating face' ofthe clutch Y hlockand the inner surface .29ffof1theclutdh barrel i9 lis 1a roller30. 'Thecperating surfaces .of

' the clutch block 2282 are eccentric 'to the inner surface of the clutchbarrel 'and `the roIlersare -fso `dirnensioned Athat they lwill' 'be-ffrictionally' :gripped by theV l'clutchblock :and `pressed *into frictional gripping engagement 'with the inner face of the :carrying a lbamlfstud -341to' whicha `link 35 is con- .nected .This'lli'nk 5351's connectedlatits'othervend :to aslotted 'arm-fmounted on arenariaY 31 AThe carries .-anarm :38 '.to'which isrionnected Yan eccentric'- strap-' 9 cooperating :with an i eccentric 4U zionntlre 4'main :shaft': ias #the :main shaft lrotates ithisneccentr'ic,,will-:through the v'train of t mechanism' iustrlescribed :impart' oscillations to e clutch pIateiandmSther'lutch blockfmoves first I oneV ,aimee-tion` :and `then the other; :gripping .the rollers 4to anovefhe-:clutchcharrel when rollers so that the clutch block can be returned by a counter-clockwise movement to obtain a new clutch grip on the clutch barrel.

The clutching mechanism which serves to hold the shaft I9 in a set position is similar to the clutch mechanism for actuating the lshaft except that the clutch block 4IV is i'lxed to the sleeve l0 which in turn is fixed to the frame and held from :mo-vement. This clutch block 4| has the similarly shaped clutching faces 42 which engage rollers '43 `and force the same into gripping contact with the clutch barrel 29. The clutch barrel will be turned by. the actuating clutch block through `a given increment of movement and,

when the Lactuating clutch block is turned in the opposite direction for a new gripping connection withthe barrel I9, this barrel 20 will wedge the roller against the stationary clutch block 4l and prevent any turning of the shaft 9 in a reverse direction. Associated with therollers 43 'are compression springs 44 mounted on studs car- Vried y'by pests L15 'which are rigidly ati'laclfiedk tothe sleeve i@ and therefore these posts and springs are Vstationary the same as the clut'cl'i.y block 4I.

The .clutch .plate 25a is provided with an annular groove or channel 46 inthe upper face thereof. Oil may be supplied to this channel through openings 41' in the gear I3. There are cil holes 48 through the clutch plate 25a which are disposed between the posts 32 and the Arollers Yfor reciprocating .the clutch.

, In the operation -o-f Ithe Yactuatingclutchl the roller is gripped 'between the clutch block. and the inner `:surface A29 of Vthe clutch barrel. :If-the gripping line ofthe roller Withrthe clutch block were always in the same position, the clutch block would Wear rapidly, forming a pocket which would soon rpermit the clutch to slip. One of the purposes of the invention is to provide 'a construction wherein the line of-grip betweenfthe roller and the clutch block shifts for each'increment ofmovement of the clutch barrel. Thisshifting `of' the gripping line -of the'v clutch roller with the clutch block is accomplished by the eccentric setting of the clutch barrel. Y

As has already been noted, `the'outersurfa'ce of Ithe hub '2| Vis eccentric to the center of the shaft. Thecenter of `the inner surface of 'the' clutch barrel is also eccentric to the center of the hub.

Referring to Figure .10, the circle indicated at Xis the circumference of the shaft Yand the center of the :shaft is ,indicated at 'cs'. The. circle Z indicates the circumference vof the .hub and the ,center of the hub as shown in this View it at ch. The center of the inner surface of the clutch barrel, which is not indicated in this view, t' is shown `at cb. When the centers cs, ch and Vcb are in alignment, then'the clutch barrel is at its vmaximum eccentricity. In the preferred setting of these centers, the distance from the center of the shaft to the center of the hub vis .005 'inch andthe distance from the center of the hub to the center 'ofi the barrel is .005inch so that when the centers are in the position shown in this diagram, the eccentricity of the barrel lis .O10 vinch from the center of the shaft. The set screw'25 is shown on this diagram and lindicates ythe setting of the clutch barrel on the hub when the flat on the hub hasibeen brought opposite the set screw 25. At this setting, the eccentricity of the clutch ,bar-i rel is as noted .010 inch. Byloosening the. set screw 25, 'the clutch barrel can .be shifted on the hub so as to bring the set screw ..24 -oppositefthe :dat This anglefofshift is abouto degrees .and

when the set screw 24 is turned up against the -rel is .00'7 inch. Again by loosening the Vscrew 24 the barrel can be shifted about the hub until the flat is brought opposite the set screw 23, This shifting is through an angle of about'130 and when the set screw 23 is set up against the flat, then the eccentricity of the clutch barrel is .004 inch. The center of the clutch barrel as it is shifted about the hub moves in thecircle indicated at Y and at one time it passes through the center of the shaft so that the eccentricity of the clutch barrel then is zero. In other words, the clutch barrel is concentric to the center of the shaft.

The set screws may beaccessible-by removing Vthe cap plate of the machine, but prefereably the vhousing has an opening 49 at the-front thereof.

Opposite the set screw is an indexing numeral 4 (see Fig. 3) and this indicates that when the flat on the hub is opposite the set screw 23,*the eccentricity of the clutch barrel is .004 inch. A

like indexing numeral 1 is applied to the outer face of the clutch barrel oppositey the set screw ',ing of the feed cup prevents the flat from shifting.

The set screw 24 is then tightened. lThe other` set screw may also be tightened against the hub to aid in holding the clutch drum in a set position on the hub. In like manner, the'eccentrivcity may be further adjusted by shifting the clutch drum to bring the set screwv 25 opposite Ythe at. It is noted that the flatr l5 at thev upper end of the shaft, the flat 22 on the hub, and the flat 4a which is contacted with by a set screw 4b to lock the feed cup -to the shaft are all in alignment. This greatly facilitates the assembling o'f the parts.

There is shown diagrammatically in Figure 9 the inner surface of 'the clutch barrel,Y a'clutch block and one of the rollers. The clutch barrel is set eccentrically to the center of the shaft and :therefore the center of the clutch barrel will move in the circular path cb. In this view, the position of the gripping surface of the clutch barrel when` 'the maximum Aeccentricitycis at the upper side of -the figure is indicated by the circle 29a.

The gripping surface of the clutch barrel when the eccentricity is down is indicated'at 29h. The position of the roller when the eccentricity is up is indicated at 3l)a and itv will Ygrip the surface 2i)a of the clutch barrel at S and the clutch block at A. When the eccentricity is down, then the roller shifts to the position 39h so that it grips the clutch barrel surface 2lib at S and the clutch block at A'. It is noted that the line of grip `of the roller and the clutch block shifts from A to A' during the rotation ofthe 'clutch barrel through 180 degrees and through the next rotation of y180 degrees the line of grip will shift back `from A to A.

,of the surface is to'provide a substantially conv 'and the clutch barrel shifted until the screw 24 is 6 stant wedge angle for all positions in which the roller is gripped by the` clutch block. The wedge angle is the angle between a line tangent to the roller at the point of contact S` between'the roller and the clutch barrel and a line tangent to the roller at the point .of contact A ofthe roller with the curved surface 28. A wedge angle is selected with the clutch barrel at maximum ec'- centricity and the roller at the position 30a, which wedge angle will prevent slippage, and the curvature of the clutch block face is so shaped that the wedge angles for each gripping position 'of the roller as it shifts back and 'forth on the face of the clutch-block will be substantially equal regardless of where the gripping of the roller by the clutch blockv occurs.' The center of the curved surface 28 is determined bydropping a line from the center O 'of the roller through the point of contact A, and where this lineintersects a line drawn at right angles thereto and passing through the center Cof the shaft determines the center'ofthe curved surface of the block. This center is indicated at D. The angle between O-D and O'-C equals the wedge angle for the roller in the position 3i)a and likewise the angle between O1'D and O'-C equals the wedge angle for the roller at the position 30h. These wedge angles are substantially equal and likewise the wedges angles for all gripping points are substantially equal. With this shifting of the gripping line back and forth foreach rotation of the clutch barrel and with the wedge angles substantially yequal at all portion-s of grip, the life of the clutch is greatly increased before the wear on the clutch block` will be suiiicient so as to change any ofthe wedge angles to produce slipping.

The machine is equipped as above noted with Vmeans whereby the eccentric setting of the clutch barrel may be varied by loosening the screws securing the clutch barrel to the hub and shifting the same on the eccentrichub. The machine is preferably adjusted at the factory so that the Screw 23 is in contact with the flat and this pro- 'vides for an eccentricity o'f .004 inch. -When the machine has been operated for some time and wear occurs, then the set screw 23 is loosened opposite the flat. This increases the eccentricity of the setting of the clutch barrel and it will alsoincrease the distance between A and A', vthe limits ofthe area where the roller grips the clutch block, and bring new surfaces into contact with the roller. Then again, when wear is apparent, the set screw 24 can be loosened and the screw 25 brought opposite the flat and this will increase the eccentricity of .010 inch and it will also further increase the distance from A to A over which the line of contact between the roller and the clutch block shifts. By these three settings, the area of the line of contact is increased from the original setting and thus the wear and life of the clutch are prolonged. Regardless of the eccentricity of the clutch barrel, the wedge angles for all setting will be substantially constant. This not only permits a greater range of adjustment of theeccentricity, but it also prolonge the life of the clutch before wear can possibly change the wedge angle sufficiently to bring about slippage.

Let us assume that the machine is set for producing ten stitches to the inch and that the inner circumference of the clutch barrel is five inches. Then for each rotation of the clutch barrel there would 'be ftyY increments of movement of the clutch'barrelf" While moving the clutch barrel'through.18.0.Jdegrees there. `would `be twentyeve increments-of movement, Let-us 4assume that the .distance fronilA--A is at a maximum because ofthe setting of the clutch 'barrel' vat a maximum -eccentricity Each increment iof movement` alongxthis line A-A would ybe 1,55 the'distance.` If' thezeccentricity Iof vthe `clutch barrel is shifted sofas to shorten the line A-A still the increments of movement would be of whateverY the distance is and therefore the distance between .the vlines of' Contact for one setting will be different 'than the distance between thelines-of lContact for. another setting of theeccentriciiw of the. clutch barrel. '.ituthier Yaids inthe distnihutionfof the wear aon the'surface fromA-LAC f i This construction vof clutchv wherein the Vwedge -angieis maintainedsub'stantially constant .for all 'points of -grip accomplishes twoY distinct advantages in the voperation of4 an eccentric-ally set clutch barrel." One, it enab-l'es'the wedge angl/e to be selected which willgive a long'lfe tov the crutch before. the Wear on'the clutching face `of the clutch block will be .sufficient to produce:

`this constant wedge angle clutch Vall three rollers 1 may have the same Wedge. angle and 'therelore each roller will carry about the :same amount of lead .which'rerluces the wear rate.

Vinstead of the rollersV .ballsv might .be used. Itis preferred, however, ato use. rollers,as the-contact between the rollers. and the partssd'irectly This rclutch block .being curved soithat the wedge angle is substantially constant for all gripping positions` of the rollers.'

vrassociated therewthis a line contact instead of Y a pointcontact. While the :clutch has been "described :in detail inconnection with a feed cup type ofV machine, it will `nowzloe understood that the clutchmay be -used for'imparting intermittent movementr toa `rot-ary part in other typesfof Y feeding mechanisms andralso Vin other types =of machines. i

lt will alsobe Vobvious that minor Ichanges .in

the details of construction may be made without departing from the spiritof the invention asset forth in the appendedv claims; f

' I claim: Y

' 51. A 4v@hitchnieclfianism for sewing machines x comprising an actuatedshaft, a clutch barrel on said shaft, a clutch block-'associated with said barrel, gripping rollers between the clutch block positions of the rollers.

Seurin'Nv er 2. A clutch mechanismfor 4comprising an :actuated .fshafaa hub on Asaid shaft, vthe center of which 'is eccentric "to :the

rs1/raft, a .sleeve .mounted zonxsaid hub, a clutch .barrel ion saidsleeve; said clutch barrel ibeing eccentric 'to '.tli'eefcenter of the E1hub,f2a .clutch block 3. A .clutch mechanism for sewing machines comprising `an Aactuated: shaft, a `hub on .said shaft, thecenter ofrwhfic'h' is -eccentricto the center of the shaft, a sleeve on said hub, a driving clutch barrel and a Abraking.clutch barrel carried. by said. sleeve, the clutching surface of each barrel being eccentricfto the center of the hub, a clutch block associated with each barrel, means for holding one of :said: clutch blocks stationary, 'and means `for actuating the other clutch block, :rollers associated with 'each'- clutch 'block for gripping the clutch barrelsgand' a compression tending to 'holdV the rollerir-rclutchin'g engagement withthe clutch blocksand clutch barrels,

the clutching faces of' :each Aclutch block being curved so: that the wedge .angle is substantially 'constant for all. lpositionsvof the: rollers.

4. A clutch Irneclflanismy for'iseWi-ng.' machines comprising an actuated shaft', a hubron' 'said shaft, the center .of which is .eccentricv tofthe center` of the shaft, y`a :sleeve `on `said hub', .adrivving l'clutch' barrel.V and Aa braking vclutch .barrel carried' by said sleeve, the clutching surface of each barrel being/'eccentric to the center l'oi-the hub, a clutch block vassociated with reach barrel, means for holding one .of'said clutchblo'clrs stationary and :means for actuating the other clutch block, rollers associated with each clutch block 'for gripping the. clutch barrels, a .compression spring associatedwith each-roller and normally `.tending to Vhold' the roller in clutching engagementwiththe. clutch blocks andclutch barrels,

.the'clutching surfaces offthe clutch .blocks being curved so .that the wedge fangle. is vsubstantially constant for all gripping.'pos`itions of' the rollers.v

5. A .clutch- :mechanism 4for sewing machines v'comprising an actuatedy .Shar-t,V a hub on said shat, .thecenter of Vwhich 'is' .eccentric to the cen- Vrter of thefshart; a clutch "barrel mounted on said hub, the center of .the- `clutch barrel v.being eccentric to the center .of `the hubya clutch block as.- sociated with said barrel, .gripping rollers.' between ftheclutch block 'and said barrel, Vmeans for oscillating the clutch-block'for moving the .barrel intermittently', vandmeans whereby said clutch 'harrel-v may .be shifted fonsaifd :hub to. :different set positionsriforvarying'the eccentricity ofthe clutch "65 barrel relative `to .the center of the shaft.

6. A. clutch `mechanism'.forsewing machines comprising an actuatedlshaft'a hub onv said-shaft,

`the center 'ofiwlichis :eccentric to. the 'center of the .'s'hat, 'said' "hub .having .a :flat on one side .thereo'afsle'eve 'mounted 'on'fsaid hub, ya clutch barrel carried by sa-id sleeve, the center of the clutch barrel being eccentric 'to the center of thehub, a 'clutch block associated 'with said bar- :relgfgripping'rollersbetween they clutch 'block :and said barrel', 'means .iforloscilifatingthe clutch'blcck for moving said barrel intermittently, said sleeve having set screws extending therethrough at different radial points whereby a selected set screw may be positioned in radial alignment with the flat for securing the sleeve to the hub and by shifting from one set screw to another the eccentricity of the clutch barrel may be varied, and means associated with each set screw for indicating the eccentric setting of the clutch barrel.

7. A clutch mechanism for sewing machines comprising an actuated shaft, a hub on said shaft, the center of which is eccentric to the center of the shaft, a clutch barrel mounted on said hub, the center of the clutch barrel being eccentric to the center of the hub, a clutch block associated with said barrel, gripping rollers between the clutch block and said barrel, the clutching faces of each clutch block being curved so that the wedge angle is substantially constant for all positions of the rollers, means for oscillating the clutch block for moving the barrel intermittently,

10 and means whereby said clutch barrel may be shifted on said hub to different set positions for Varying the eccentricity of the clutch barrel relative to the center of the shaft.

EDGAR SCHOIJ.

REFERENCES CITED The following references are of record in the le of this partent:

UNITED STATES PATENTS

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