US2481175A - Presser foot - Google Patents

Description

Sept. 6, 1949 F. P. TAMBURRO PRES SER FOOT 3 Sheds-Sheet 1 Filed Feb. 28, 1944 INVENTOR j mflvis P Tamurro ATTORNEYS Sept. 6, 1949. F. P. TAMBuRRo PRES SER FOOT 5 Sheets-Sheet 2 Filed Feb. 28, 1944 lNyENTOR liramcw]? Tamburm,

ATTORNEYS Sept. 6, 1949. F. P. TAMBURRO PRESSER FOOT 3 Sheets-Sheet 3 Filed Feb. 28, 1944 ATTORNEYS Patented Sept. 6, 1949 PRESSER, FOOT Francis P. Tamburro, Ozone Park, N. Y.. assignor to Willcox & Gibbs Sewing Machine Company, New York, N. Y., a corporation of New York Application February 28, 1944, Serial No. 524,159

8 Claims. (Cl. 112- 235) This invention relates to sewing mach nes, and more particularly to machines adapted to stitch together the edges of fabric sections and the like to form felled seams.

An object of this inventon is to provide an improved presserdevice which is so articulatedand controlled that it functions to maintain a close control of the material at the felled seam regardless of wide variations in the thickness and size of said seam, as caused by the meeting and interfolding of cross-seams in the material.

This is accomplished by a novel mounting of a front presser foot and a rear presser foot in tandem for pivotal and translational movement whereby thepivots are so located with respect to each other and to the work that movement of the presser feet in riding over cross-seams in the work is in a direction which has no component opposing the feeding movement of the work. As a result, a uniform and positive work feed is obtained.

When joining fabric sections which have felled cross-seams by sewing the sections together using a felled scam, I have found that the most difficult condition for feeding and sewing arises when the fabric sections are arranged so that theleading ro llof the cross-seams is on the top of the sections where it will contact the front presser foot ahead of the rest of the cross-seam, such contact usually being abrupt and having a certain amount of impact, especially when the speed of the work feed is substantial.

- It is another object of the present invention to provide an improved presser device which functions to effect apositive work feed regardless of whether the roll of the cross-seams onthe top surface ofthe work is leading or trailing as the seam approaches the presser feet.

This is accomplished by providing an auxiliary pressure means associated with the rearpresser foot and functioning independently of the pressure of the presser bar of the machine but augmenting the latter whereby the pressure on the work of the front foot and the rear foot, has a relation which results in a uniform feeding of :the cross-seams past the sewing means of the machine.

A feature of the invention is the provision of an improved material control means as above which may be readily adapted to existing machines with but little change being required. 1

Another feature of the invention is the .provision' of means as above which are simple to manufacture and reliable in operation.

. Other features and advantages will hereinafter appear. r In the accompanying drawings- .Figure 1 is a fragmentary side elevation of a machine embodying the invention.

Fig. 2 is a fragmentary side elevation of the material control means of the invention, showing the tandem-arranged presser feet in lowered position, and showing felled cross-seams approaching same. I

Fig. 3 is a similar view showing the action of the presser feet asv the cross-seams begin to engagethe forward foot. y

Fig. 4 shows the action of the presser feet as the cross-seams reach the pivot point of the forward foot. s

Fig. 5 shows the position of the. feet when the cross-seams are just past the pivot point of the forward foot, and beginning to engage the rear foot.

Fig. 6 shows the position of the feet when the cross-seams are raisin the front part of the rear foot.

Fig. '71s a view like Fig. 2 but partly in section, andshowing the relative positions of the feet as the cross-seams reach the pivot point of the rear foot.

Fig. 8 is an exploded view of the improved tandem presser-feet control.

' Fig. 9 is a vertical section taken on the line 9-9 of Fig. 2.

Referring; to Fig. 1, a sewing machine embodying the present invention is shown as having a supportingarm 12- extending in a lateral direction to. cooperate with a sewing head 13 which supports the presser. bar and needle operating mechanisms of the machine. Needles M are mounted for reciprocating movement in the usual manner, and cooperate with loopers (not shown) in the work-supporting arm 12 for .stitching work,-which may comprise fabric sections and the like, fed over the arm. As shown in Fig. 2, feed dogs l5 are provided to feed the work [6 past the needles I4, said dogs beingmounted for fourmotionmovement in the arm l2 and having teeth extending through apertures in a throat-plate l1.

feller or interfolder i8, Fig. 1, is located on the arm l2 ahead of the needles [4 for automatically interfolding the edges of the fabric sections in advance of the needles to be joined by thestitching. As shown, the feller I8 is of the type adapted to handle sections having felled cross-seams whereby the latter as they are made to meet or align are interfolded at their ends in the same manner as the rest of the edges making up the seam.

. .The machine shown may be of the type oommercially-well known as theWillcox and Gibbs SewingMachine Company's Feldlock Machine, as illustrated in Patent No. 1,796,111, issued to G; M. Lewis March 10, 1931.

Accordingto the present invention, for controlling the felled edges of the work it after they leave.the feller 18, there is provided an'improved presser means cooperating with the feed dogs l5 and .throat-plate l1 so as to cause the felled the thickness of the seam may be of considerable magnitude, since as shown in Figs. 2 through 7, the thickness of the seam 20 at the point '2! where the two felled cross-seams l3 meet and are interfolded is equal to sixteen. times thethl-ckness of a single fabric section-. 22,Whereas1the thickness of the seam where there are no cross-seams, is only four times that of a single section. This improved presser means,-in the embodiment shown, includes tandem-connected feet pivotally mountedin. an improved advantageous manner, and .yieldably. held in engagement with the work in a novelway whereby they function to insure uniform feeding of the work past the needles l4.

As shown in Figs. 1 and. 2, the head I 3 has axially movable thereinbetween extended andv retracted positions, a. presser bar 23 which is non-rotatable and yieldably urged toward the work-supporting arm "l2 to extendedposition by a helical coil sprin 24. The lower portion of the barl23extends adjacent to the needles l4, and carri'es'at its end a bracket 25' having a split-collar 2t" and draft screw 21 by means of whichthe bracket is. secured to the bar. Referring to Figs. 8an'd 9,'the "body of the bracket 25constitutes ayoke i 28 having a pair of depending lugs 29"which'are apertured to pivotally carry a pair of rocker arms 30' at the centers thereof, saidarms being pierced and "threaded to receive shouldered pivot screws 3| for this purpose. The rocker arms 30 pivotally carry at their forward ends a front presser foot 32, and attheir rear ends arear presser foot 33, said ends of the arms 'being'apertured to receive respectively shoulderedpivot screws 34 and 35 which are in turn threaded into -upstanizling ears 36'of'thefront foot andthebodyofthe rear foot.

'The front presser foot'32 has'a body '3'L the underside 38 of which constitutes asubs'tantially planar work-engagin surface, said bodyha'ving needle apertures 39'and an upturned toe 40,th'e latterbeingadapted to guide the foot "over irregularities, such 'as cross=seams and thelike, in the work.

"For the purpose of guiding the reuse seam 23 which is being sewed, the body'3'l of the front presser foot has along its sides depending flanges flland '32 respectively, which preferably'extend toa depth the equivalent of three thicknesses of a single fabric section. Thus, as shown 'in Fig. 2;"wh'en a portion of the felled-seam'm which has'no cross-seams is passing'between the foot 32 and theithroatplate I! the flange-el-exten'ds past the side of the roll comprising the upper three 'thickne'sses'of the seam, and engagesand guides said side-and the'fabric section 22. The flange 42 on the'other side of the foot depresses the top fa'bric'sectio'n 22a at points alongside the seam 20,'as' seen in Fig. 9, so that the latter is accurately. guided and prevented from having side movement while 'being'sewed. 'Ihe flange E2'is continued along the un'dersi-deof the toe but tapers off toward the tip, as shown by the dotted line'42a in Fig. 2. The flange 4| is also continued along the toe 40 to taper off at-the tip, but it first deepens at the point- 43 in order to adequately guide the seam 20 where a deep rolloocurs, as at thepoint2l showing two'crossseams interfolded.

The underside 44 of the rear-presserfoot33 constitutes a planar work-engaging surface also adapted to press against theseam 20 and the front endof said foot has a pair of spaced toes extending forwardly thereof into slots 46 in the rear portion of the foot 32, the under edge of the toes sloping upward as shown to cause the"foot to rise above obstructions such as crossseams and. the like. Spacing is provided between :the: adjacent interfitting portions of the feet 32 and -33 so that-each of the latter is independently pivotally movable on the rocker arms 30 with re- 1 spect to the'other within a predetermined range.

This-range is such that the feet do not interfere with each other as they pivot and bodily move in individually following irregularities in the work.

As thus pivotally mounted, the presser feet32 and 33 are adapted to engage and guide the felled seam 20 as it is being sewed by the needles M, said feet being made to press -firmly against the seam by thespring 24 acting on the presser'bar 23.

It will be noted that the three plvotpoints of each rocker armare located substantially in a straight line, equi-spaced from the seams2ll, the intermediate pivot being preferably substantially' midway betweenthe end pivots to divide the pressure of the spring 2 1 equally-between the feet. "This results in an important advantage 'Whenjoining seamed'fabric sections, or sections havingoth'er irregularities which'might interfere with uniform feeding of'the sections past the needles. -Ri=ferring to Fig.2, when a'felled seam is being sewed at apoint removed from crossseams so that the latter do not engage the'presser feet 32 and 33, no feeding problem is encountered since the work-engaging'surfaces'38 and-44 of the feet are in'alignment and the three pivot points of the rocker armsare equispaced from the seam.

"When cross-seams l9 approach the needles H, as seen in Fig. 3, they'first engage the front presser'foot 32 causing it to pivot and also bodily lift,'and causing a canting 0f the rocker arms 30, accompanied by a retracting of thejpivot 3| and presser-bar 23. This increases the pressure exerted by the spring 24, and as a result the pressure exerted by the feet 32 and 33 on the work. Dueto the fact that the pivots of the rocker arms 30 are initially'equispaced from the seam 20, theinitial retracting movementof the front foot 32 is" substantially perpendicular to the line of feed of the seam, and the subsequent retracting movement of the foot is in such a direction that there is no component opposing the feed'cf the seam, nor the feeding movement of the feed dogs [5. Asa result, feeding of the work proceeds'with the least amount of interference from the'front'foot. 'If the'center pivot 3| "of the rocker arms were spaced further'from' the work thanthe'corresponding spacing of the two end pivots, so that it was higher than same, the initialretracting movement of the front presser foot would notbe perpendicular to the line of feed of the seam 26, but would have a component opposing the feed of same and the feeding movement of the feed dogs I5. 1

Similarly, the location of the center pivot 3|, in line with the end pivots so that all three'are equispaced from the seam 20, reduces'the amount of feed-opposing movement of the rear foot which takes place during the retracting movementof thefront foot. By thus eliminating and reducing the forces opposing the feeding movement of the seam20'during the interval that the front foot 32 is riding'upand over an obstruction such as cross-seams l3 interfoldedas at 2l,"a=mor'e positive and uniform feed is assured during said interval. It is during this interval-that-the sew ing of the interfolded'cross seamstake place', as seen in Figs. 2 through 5. V

As seen in Fig. 4, the front presser'foot 32'has entirely mounted-the interfolding 2 I of the cross seams l9, and'the needles I4 are stitching at the center of said interfolding. In'Fig. 5,the needles are completing the stitching cf-theinterfolding 2|, the front foot 3'2 being canted at a'comparatively sharp angle, and the rear foot 33fbeginning to cant as it starts to mount'the cross seams. At this position the center'pivot 3| is comparatively high and its spacing from the work is-greater than the spacing in Figs. 2 and 3. Now, as the interfolding 2! of the cross-seams leaves the front foot 32 and passes completely under the rear 'foot 33,"Figs; '6 and7 ,"the .latter foot in mounting over the seams moves' in a direction which again has no component opposing the feedof the seam. Thus; theaction of the presser feet androcker arms, as provided above by the invention, is such as to not interfere withfthe continued feeding and sewing of the seam 2il, yet these individually and collectively function to maintain a pressure on the fabric sections and seam thereof whereby the feed dogs I5 uniformly feedthe'workpast the needles. Where particularly heavy fabric sections having' felled cross-seams are to be joined, and especially if the cross-seams are fed with the leading roll of the seam on the top of the work where it will contact the presser feet; as shown in the figures, the invention provides'novel means further regulating the action of the presser feet 32 and 33 to insure a positive and uniform feeding of the seam 20. In theembodiment shown,

this embraces a mechanism for providing the rear presserfoot with a pressure component, to be transmittedto the work, that is independent of the pressure supplied by the bar 23 and functions to supplement said latter pressure in a" manner to maintain control at'all times of the seam being sewed. A

Referring to Fig. 1, the bridge portion 13 of the machine is provided with a stud l3b on which is mounted a rocker 4! having an arm 41a. Secured to the arm 41a is an extension 41b projecting toward the presser bar 23 and terminating between the end of the latter and the rear presser foot 33. The end portion of. the :extension 411) is divided into two fingers 49 and'ill, the finger 49 extending closely against theface 23a oft-the end of the bar and being adapted to engage same, and the finger 5'3 being located adjacent the upper surface of the rear foot 33 and'having'ade pending boss. 5! carrying a helical coil spring 52 extending into a recess 53 in said foot,isee Fig. 7. When the presser feet 32 and 33 are in extended position engaging the .work 16, and the extension 41b is in lowered position, as in Fig. 2, the finger 49 is spaced an extent from the end face 23a of the bar. and the spring 52 is compressed and presses down on the rear foot 33 at a point below the pivot thereof to yieldably .hold same horizon-- tally and evenly in engagementwith the'work. Thus the pressure exerted by'the rear presser foot 33, as supplied by the spring 24' of the' 'presse'r bar is augmented by the i'ndependent pressure of the spring 52. InFigs. 3a'nd 4, showingprogressive stages in the advance of the Work, the spring 52*does not change appreciably from the setting OfiEiE. P 2,. but acts continuously-to ipress idownion the rear foot 33 for supplementing the pressure of the presser bar spring 24. In Fig. 5, where the felled ends 2| of the cross-seams begin to engage and move the rear foot 33, the spring 52 is compressed a slightly greater extent. Figs. 6 and '7 illustrate still further compression of the spring 52 as therear foot mounts and rises over the felled ends 2| of the cross-seams, the latter figure showing the spring being compressed a maximum amount. As the spring 52 is compressed it exerts a greater pressure on the foot 33, and the latter on the seam 23, so that the feed dogs 15 encounter greater pressure and bite more deeply for these conditions, and therefore the likelihood of slippage occurring is reduced. As a result, this further regulation of the presser feet as accomplished byv the spring 52 efiects a more uniform and positive feeding of the work.

When theypresser. feet and 33 are to be raised from the work IS the rocker 41 is turned slightly in acounterclockwise direction by an arm l'lc, thus raising the arm 41a and extension 4112 an extent. After. the extension 41b has moved a short distance the finger 49 thereof engages the end face 23a of the bar 23, and further movement of the extension carries the bar, and the feet 32 and 33 to-their retracted position. The extension 41b and bar 23.niaybe locked in theirraised or retracted positions. until the new work is inserted in the machine and the latter is ready for sewing.

For the-purpose pf preventing the front foot 32, when raised or retracted, from eantin in a clockwise direction whereby the toe 43 thereof would be loweredand would hamper insertion of new work, a flat spring 54 having a pair of arms 55 is mounted bymeans of a screw 56 on the rear face Of the yoke 28, the ends of the arms 55 being formed; into elongate eyes 55a, Fig. '7, which encircle and engage pins 51 respectively carried by the ears35 of said front foot. The spring 54 is arrangedto maintain the front foot 32 in a substantially horizontal position when the latter is retracted, free from the work.

Variations and modifications may be made within the scope of this invention and portions of the improvements may be used without others.

I claim:

' 1. A sewing machine having a throat plate; a presser bar; a front presser foot and a rear presser foot; means for mounting the presser feet in tandem on the presser bar to be bodily movable therewith and between limits relatively thereto whereby they are positioned under pressure supplied from the presser bar to engage and move independently of one another to follow variations in the thickness of'a workpiece passing over the throat 'plate; and means independent of the presserjbar and applyin pressure to the rear foot, yieldably holding the latter in worx engaging position and providing a force thereon in addition to that supplied by the presser bar.

2. 5A sewing machine having a frame; a throat plate; a presser bar; a front presser foot and a rear presser foot; means mounting the presserfeet. in tandem," and so that eachis pivotally mounted to turn independently of the other; means for pivotally mounting the mounting means on the presser bar whereby the presser feet are bodily movable relatively thereto between limits and are positioned by pressure supplied from the presser bar to engage and move independently of one another to follow variations in the thickness of a workpiece passing over the throat plate; and yieldable meansmounted on the frameand bear:-

ing upon theirear presser foot, operating :independently of the presser-bar, for yieldablyholding the foot in'work-engaging position :whereby the total feeding pressure exerted on the workpiece has .a component independent :f .the pressure variations resulting from movement of the presser bar :due to rising'and falling of the front foothin traversing a cross-seam.

3. The invention as defined in claimv2xin whic the. independent yieldable holding means i for 113116 rear foot comprisesa spring pressing onttheyfoot at-a point between its pivotal axis and its work engaging surface along a line normal to said surface when the foot is engaging a workpiece whereby the pressure ofsaid foot on the workpiece due to the spring tends to;distribute itself evenly over the work-engaging surface.

4. A sewing machine having a throat'plate; a'presser bar movably mounted on themachine frame adjacent the throat plate to have a predetermined line of movement intersecting the plane of feed of the work, and beingyieldably urged toward an extended position close to the throat plate; a front presser foot and a rear presser foot'each having planar work-engaging surfaces: a link mounting the presser feet in tandem by pivots located substantially equidistant from their respective work-engaging surfaces, said feet having their juxtaposed portions disconnected and-provided with clearance therebetween whereby the feet are free for independent purely rotative movement with respect to one another, and the link being pivoted on the prerser bar-at a point aligned with and intermediate the pivots 'of the presser feet whereby when the presser bar is in extended position said feet under yielding pressure supplied from the'bar so engage a workpiece that all the pivots of the link are substantially equi-spaced from the line of feed, and whereby movement of the front foot away from the surface of the'throat plate due to engagement of said foot with a cross-seam has no component opposin the feed of the work; and yieldable means independent of the presser bar, engaging the rear foot to yieldably hold the latter in work-engagin position and exert a 'force thereon in addition to that supplied by the presser bar.

5. A sewing machine having a, throat plate; a

presser bar; a front presser foot and a rear presser foot; means for mounting the presser feet in tandem on the presser bar to be bodily mbvable therewith and between limits'relatively thereto whereby they are positioned by pressure supplied from the presser bar :to engage and individually move to follow variations in the thickness of a workpiece passing over the throat plate; means functioning independently of the presser bar and bearing upon the rear foot for yieldably holding the latter in Work-engaging position whereby the total feeding pressure exerted on the workpiece has a component independent of the pressure variations resulting from movement of the presse'r bar due to rising and falling of the front foot 'in traversing a cross-seam; and meansforreleasing the independent yieldable holding means for the rear foot, and for moving the presser bar to retract the presser feet whereby a work-piece may be removed from under same.

6 A sewing machine having a throat plate; a presser bar; a front presser foot and a rear presser foot; means for mounting the presser feet in tandem on the presser bar to be bodily movable therewith and between limits relatively thereto whereby they are positioned byipressure suppliedffrom the .presser libar tmengage and m dividually move-to'followvariations in the thickness of: atworkpiecepassing over the throat plate; means i functioning independently of the presser bar-and engaging the rear foot for yieldably holding the latter in work-engaging position wherebythe total feeding pressure exerted :on the workpiece *hasi-a1component independent of the pressure variations resulting from movement of the presser-bardue to rising and falling of the" front 'foot in -.traversing a cross-seam; and means :for releasing the independent yield-able holdingmeans forthe rear foot and for-moving the-presser bar to retract the presser feet wherebya workpieceymay be 'removed;from under same, said sfirstenamed means including-a lever connected to-.the holding means and a lug adapted: toengage thegpresser' bar, and connectedwith saidlever.

"'7. In a sewing machine; theacombinationof; a work .tablepa presser bar mounted'adjacent the machine-needle for predetermined extending'and retracting movement with respect to the work table;;the line-of'saidmovementextendin at an angle-with respect to the line of feed'of the work; means for yieldably holding the presser barinextended position; afront presser foot and azrear-presser footreach having ;planar workengaging surfaces; a link having pivots at its ends for mounting thepresser feet in tandem, said pivots'being located substantially equidistant fromtherespective work-engaging surfaces oftthe feet, saidfeet-being rotatable independently of each --other, said link being pivoted-at its center on the-presser bar so that all pivots are in alignment-andzso that thepresser feet, under pressure supplied'by said yieldin means, engage a workpiece whereby'all pivots of the link are substantiallyiequispacedafrom the line of feed, and whereby-movementof thefront foot away from the'surface of the worktableldue toenaeementiofsaid footwith a cross-seam has no component opposing the feed-of the work; means cooperable :withrboth-plan-ar work-engaging surfaces-of the feet for. feeding a workpiece past the machine needle; a spring functioning independcntly'ofx-th'e presser-bar'disposed between an arm mounted on the" machine and the rear presser foot and engaging. the-latter at a point between the-pivotand work-engaging surface thereof, foryieldablyi holding said foot in work-engaging position;'-and-meansforyreleasing the spring and retractingnthe presser-bar to move both presser feetawav from the work table whereby a workpiece-may be removed-from betweensaid feeding means and-feet.

"8. :A-sewing machine-having a'frame; a throat plate; apresserbarya front presser foot and a rearipresser: foot;. means-pivotally mounting the presser "f-eet.;in tandem, and so that each is mounted torturn independently 'of'the other; meansfor .rpivotally mounting the mounting means .onthe presser bar whereby the presser feet are "bodily nmovable relatively thereto between'limits and are positioned by pressure supplied from the-presser bar to engage and move independently ;of one another to follow variations in the thickness of'a workpiece passing over the throat plate; and yieldable means mounted on" the; frame "and applying pressure to the rear :presser foot, operating independently of the presser 'bargfor yieldably holding the foot in work-engagingmositiou wherebythe total feed- .ing pressure-exerted on the workpiece'has a com ponentindependentofthe'pressure variations re- 9 10 Selting from movement of the presser bar due to UNITED STATES PATENTS nsmg and fallmg of the front foot 1n traverslng a cross-seam, the pivotal mounting of the rear Number Name Date presser foot being located substantially vertical- 617,751 Laskey Jan. 17, 1899 1y above the point of application of pressure to 5 8 ,399 -D5 1 1935 said rear foot by the yieldable means. 2,916,354 k an Oct. 8, 1935 FRANCIS P. TAMBURRO. 2,147,128 Sailer Feb. 14, 1939 2,156,535 Kucera, May 2, 1939 REFERENCES CITED 2,340,647 Cu'mfer F b. 1, 1944 The following references are of record in the 10 file of this patent:

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