US3093330A

US3093330A - Feeding mechanism for yarn winding and processing machines

Info

Publication number: US3093330A
Application number: US21480A
Authority: US
Inventors: Schmidt Richard
Original assignee: Franz Morat GmbH
Current assignee: Franz Morat GmbH
Priority date: 1960-04-11
Filing date: 1960-04-11
Publication date: 1963-06-11
Anticipated expiration: 1980-06-11

Description

hm; y A.

June 1963 R. SCHMIDT 3,093,330

FEEDING MECHANISM FOR YARN WINDING AND PROCESSING MACHINES Filed April 11. 1960 5 Sheets-Sheet l IN V EN TOR.

BY WWI/6M1 3. WA.

his ATTORNEY June 11, 1963 R. SCHMIDT 3,093,330

FEEDING MECHANISM FOR YARN WINDING AND PROCESSING MACHINES Filed April 11, 1960 5 Sheets-Sheet 2 HHMIM, HHHHIIHI" INVEN TOR.

R. SCHMIDT June 11, 1963 FEEDING MECHANISM FOR YARN WINDING AND PROCESSING MACHINES 5 Sheets-Sheet 3 am 8 5 6 55.. ?(1 J 4 0 a i w W W. q a m w -4 W m w H his A 7'TOR/YEY June 11, 1963 R. SCHMIDT 3,

FEEDING MECI IANISM FOR YARN WINDING AND PROCESSING MACHINES Filed April 11, 1.960 5 Sheets-Sheet 4 ZZZ VIII/III IN V EN TOR.

his Afro/Mfr June 1 1, 1963 R. SCHMIDT FEEDING MECHANISM FOR YARN WINDING AND PROCESSING MACHINES Filed April 11, 1960 5 Sheets-Sheet'S many Filed Apr. 11, 1960, Ser. No. 21,480 12 Claims. (Cl. 24245) The present invention rel-ates to a yarn feeding mechanism, and more particularly to a universal yarn feeding mechanism which is equally useful in yarn winding machines as well as in yarn processing machines such as sewing, knitting and hosiery machines.

This application is a continuation-in-part of my application Serial No. 773,427, filed November 12, 1958, now abandoned.

iAn import-ant object of the present invention is to provide a yarn feeding mechanism which may exert an accelerating or advancing action as well as a braking action upon the yarn to insure uniform movements of yarn to the needle means of a knitting or sewing machine or to the spindles of a winding machine under all kinds of working conditions.

Another object of the invention is to provide a yarn feeding mechanism of the above outlined characteristics which is of very simple construction and which may be readily incorporated in many types of known winding, sewing, knitting and hosiery machines without requiring substantial modifications in the construction and design of such machines.

A further object of the invention is to provide a yarn feeding mechanism which may operate with variable degrees of sensitivity and which may be readily adjusted to change its yarn advancing or braking action.

A concomitant object of the instant invention is to provide a yarn feeding mechanism which may be utilized for simultaneous control of two, three, or more yarns.

Still another object of the invention is to provide a yarn feeding mechanism which insures uniform advance of yarn to the yarn receiving or takeup element of a Winding machine regardless of exact configuration of the takeup element and of the yarn package to be formed thereon.

An additional object of the invention is to provide a yarn feeding mechanism which occupies little space in a yarn winding or processing machine, which requires no attention once it is in operation, and which is capable of operating in a fully automatic way to adapt its yarn advancing or braking action to different operating conditions.

In circular knitting and hosiery machines of presently known design, the yarn feeding mechanism usually comprises two meshing gear Wheels which are driven by the motor of the machine. The yarn passes between the teeth of the Wheels whose axial distance is adjustable by hand or by a lever which is engaged by and is responsive to changes in tension of the processed yarn. A disadvantage of such construction is that the yarn is caused to buckle between the teeth and that, owing to inevitable slippage of yarn, an accurate regulation of the rate at which the yarn is fed is not possible. When the regulation of feed is automatic, the mechanism must comprise complicated transmissions mounted between the aforementioned lever and the wheels which adds to the initial cost and, moreover, cannot avoid at least some slippage so that the automatic regulation of yarn feed is not reliable under all operating conditions.

In so-called flat knitting machines, the yarn is payed out by spools in response to the pull of knitting needles during the formation of each successive loop. The required tension is generated by conventional yarn tensioning and braking devices. In order to insure uniform loop forma- 3,@3,33ii Patented June ll, 1963 tion and to produce a knitted fabric of uniform elasticity and stretch, the spools must supply the yarn at a uniform rate. Despite careful winding of the yarn onto such spools, certain irregularities in the formation of convolutions on a spool and varying tensions in the yarn body on the spool cannot be avoided. During unwinding of differently tensioned or improperly convoluted yarn portions, the yarn must be drawn by knitting needles with an increased force which results in irregular loop [formation or may break the yarn. In addition, since the needle carrier performs a continuous reciprocating movement with respect to the supply spool, the distance between the yarn guide and the supply spool is subject to continuous changes which also contributes to variations in the tension of the yarn.

The yarn feeding mechanisms presently utilized in circular knitting machines comprise pairs of rollers or meshing gear wheels which should advance the yarn at the exact speed at which the yarn must reach the needles. Such speed is comparatively low and, therefore, the feeding mechanisms must be equipped with costly step-down transmissions. To utilize such feeding mechanisms in flat knitting machines would result in greatly increased cost, particularly if the feeding mechanisms are to operate in a fully automatic way, i.e. if their rate of speed should be subject to automatic changes in response to varying degrees of yarn tension.

The situation is reversed in yarn winding machines, i.e. in such machines which wind a yarn package onto tubes, bobbins, spools, cones or other types of yarn receiving elements for storage or for use in knitting, hosiery and sewing machines. In all such winding machines, the yarn must be wound under constant and uniform tension since, and as explained hereinabove, any changes in such tension may cause irregularities in the characteristics of knitted or otherwise produced fabrics. In addition, any irregularities in the tension of yarn supplied to a spool or other yarn receiving element in a winding machine may cause irregularities in the formation of convolutions such as may again cause unsatisfactory advance of yarn from the yarn receiving element to the knitting needles, sewing needles or the like. Different tension in the yarn supplied to a yarn receiving element in a winding machine may develop as a result of irregular operation of the thread guides, as a result of a shift in the position of supporting means for the yarn receiving elements, as a result of changing resistance to withdrawal of yarn coming from the spinning room, or as a result of irregular operation of brakes.

In sewing machines, one or more yarns are engaged by the sewing needle and by one or more catchers or grippers. On their way to the needle and to the catchers, the yarns are subjected to a braking action and are subjected to different degrees of tension during the formation of consecutive stitches. The braking means usually comprises two spring-biased discs which receive the yarn therebetween. Different degrees of tension in the yarn are caused by changing the distance which the yam must cover between the braking means and the needle. A disadvantage of such conventional .discoid yarn brakes is that they fail to react to comparatively small fluctuations in tension and that they produce undesirable braking action if the yarn is of non-uniform thickness.

The improved yarn feeding mechanism overcomes the above outlined drawbacks of aforedescribed conventional feeding and braking mechanisms and consists essentially of a rapidly rotating referably cylindrical roller whose peripheral surface is of mirror-like smoothness and tempered hardness. Depending on its rotational speed and on the direction of its rotation, the roller may be utilized as a yarn advancing or as a yarn braking means and, depending upon whether the yarn forms a fraction of a convolution, a full convolution, or more than one convolution about its peripheral surface, the roller may react to any changes in yarn tension with a higher or lower degree of sensitivity. If desired, the roller may be utilized for simultaneously controlling the advance of two or more yarns and, in its preferred form, constitutes the rotor of an electric motor. Such construction avoids undesirable vibrations and results in lower initial cost because the yarn feeding mechanism may operate without costly transmissions, externally mounted tension-responsive devices and the like.

The automatic adjusting action of the improved roller is due to the fact that any changes in the tension of oncoming or leaving yarn portion bring about changes in friction between the yarn and the peripheral surface of the roller so that the advancing or braking action of the roller becomes more positive in response to increasing yarn tension, and vice versa.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following detailed description of certain specific embodiments when read in connection with the accompanying drawings, in which:

FIG. 1 is an axial section through a yarn feeding mechanism embodying one form of my invention;

FIG. 2 is a transverse section through a flat knitting machine which comprises two yarn feeding mechanisms of the type shown in FIG. 1;

FIG. 3 is a front elevational view of a modified feeding mechanism which may be utilized with advantage in circular knitting and hosiery machines;

FIG. 4 is a side elevational view of the feeding mechanism shown in FIG. 3;

FIG. 5 is a schematic view of a spool winding machine which comprises a feeding mechanism of the type shown in FIG. 1;

FIG. 6 is a schematic view of a pirn winding machine which also utilizes a feeding mechanism of the type shown in FIG. 1;

FIG. 7 is a schematic view of a cop winding machine which utilizes a feeding mechanism of the type shown in FIG. 1;

FIG. 8 is a partly elevational and partly sectional view of a sewing machine which is combined with the feeding mechanism of FIG. 1 and in which the feeding mechanism acts as a braking device;

FIG. 9 is a schematic illustration of certain parts in a slightly modified sewing machine which utilizes two feeding mechanisms of the type shown in FIG. 1, one such feeding mechanism acting as a braking device and the other feeding mechanism being utilized to advance the yarn toward the braking device.

Referring now in greater detail to the illustrated embodiments, and first to FIG. 1, there is shown a yarn feeding mechanism P which comprises a cylindrical roller 1 whose peripheral surface is dead smooth or of mirrorlike smoothness and tempered hardness and which is rotated at a peripheral speed of, say, between 600-1000 meters per minute. For example, if the diameter of the roller 1 is in the range of about 60 mm., the roller will rotate at 75 0015000 r.p.m. Since it is highly desirable that the roller rotate without any vibration, and since it is difiicult to avoid vibration if a bod-y revolving at such speeds is driven by a system of meshing gears or other types of indirect drive means which normally include a step-up or a step-down transmission, the roller is preferably directly coupled to the shaft of an electric motor. Accordingly to an important and preferred feature of my invention, the roller 1 constitutes the rotor of an electric motor whose stator is mounted in the roller as is shown in FIG. 1. The roller 1 is shown as a cupped hollow cylindrical body and consists of a current conducting material, e.g. steel. The stator including the winding 2 is mounted on a tube 3 whose rear end is formed with a discoid flange 3a. This flange is fixed to a disc 5 by a plurality of screws 4. The disc 5 is formed with a coaxial stud 5a which is secured to a frame member 6 by means of a threaded coaxial bolt 7. The flange 3a carries a panel 8a for the terminals of conductors 8 which are connected to the winding 2.

The tube 3 rotatably receives a spindle 9 whose rear end defines a seat for a ball 10, this ball constituting a thrust bearing for the roller 1. The spindle 9 is held against axial displacements by a snap ring 11. The forward end of the spindle is non-rotatably connected with the bottom of the roller 1. Owing to the just described mounting of spindle 9, the roller 1 rotates with little or no vibration. The frame member 6 may consitute a portion of the carriage or another component part of a twobed flat knitting machine which is shown in FIG. 2. This machine comprises a frame 12 mounting a spool 13 with a yarn package 13a thereon. The yarn 14 passes over a first feeding mechanism F which is mounted on a bracket 15 vertically adjustably carried by an upright member 16. The yarn 14 may form a fraction of a single convolution, one full convolution, or more than one convolution about the peripheral surface of the roller 1, and is thereupon led through a pot eye 17 mounted on a horizontal arm 18 at the upper end of the upright member 16. The yarn 14 is then led about the peripheral surface of the roller 1' forming part of a second yarn feeding mechanism F. This mechanism supplies yarn to a tensioning and braking device 19 and thence to the needle 20.

The mechanism F may be supplied with electric current through a loose cable 21 or through the upright 16. The other mechanism F receives current through a loose cable similar to the cable 21 or, preferably, through a rail 22 which slidably supports that portion 23 of the knitting machine which mounts the mechanism F, the needle or needles 20 and the tensioning means 19, it being assumed that the mechanism F travels along the frame 12.

The arrangement shown in FIG. 2 is particularly suitable for use in connection with elastic yarns made of rubber or the like. Each yarn 14 requires a separate feeding mechanism F and a separate feeding mechanism F, or the length of

rollers

1, 1 may be selected in such a way that they may accommodate two or more yarns 14. The mechanism F may be omitted (therefore shown in broken lines in FIG. 2) and the knitting machine may operate only with the set of mechanisms F.

It will be readily understood that the provision of a yarn feeding mechanism F which may receive current through a loose cable or a rail 22 constitutes a considerable simplification if compared with a mechanism which must be driven by gears, transmissions or other indirect drives because the mounting of such indirect drives on a movable part of the machine is extremely complicated. In addition, the weight of one or more sets of such indirect drives on the reciprocable portion 23 of the knitting machine represents an additional load upon the frame 12.

The sensitivity of the

roller

1 or 1 depends upon the extent to which a yarn is convoluted about its peripheral surface and also upon the rotational speed of the roller. The higher the rotational speed, the greater the sensitivity of the feeding mechanism, i.e. the roller will react more rapidly to varying tensions in the yarn if it rotates at a higher speed. The reaction of the roller to changing tension is such that, provided the tension arises in that portion of the yarn which has already passed beyond the roller, the convolution or convolutions on the peripheral surface of the roller engage the roller with increased frictional force and the roller therefore conveys the yarn with a more positive force until the tension drops to the desired level. On the other hand, if tension increases in that portion of the yarn which is about to contact the peripheral surface of the roller, the frictional force again increases causing the roller to exert a greater pulling force upon the oncoming yarn to thus compensate for increasing resistance of yarn to the advancing action of, say, a knitting needle 20 or a tensioning device 19.

FIG. 3 illustrates a modified construction F of a yarn feeding mechanism which may be utilized in many types of knitting and hosiery machines, preferably in circular knitting machines. The mechanism F comprises two coaxial rollers lfila, 10111 rotatably mounted on a supporting member 195 which is fixed to the frame member 166 of a knitting or hosiery machine by bolts insertable through cutouts 105a, 10517. The supporting member 105 mounts a casing 108a comprising terminals 108b, 1080 for conductors (not shown) utilized to convey electric current to the motor means of which the roller 101a and/ or the roller ltllb forms a component part. The supporting member 105 further comprises an annular bracket lttSc which supports the stators 102a, 1021). These stators are secured to the bracket 1050 by bolts 124a, 1242: (see FIG. 4). The switch means 125, mounted on the bracket 105a, may be utilized for starting or arresting the roller-shaped rotor 101a and/ or the rotor ltllb.

The yarns 114 (only one shown) pass from the bobbins (arrow A) through the eyes 126, 127, and are wound once or more than once about the rollers 191a, 1011) to be advanced toward the knitting machine (arrow B).

The control switch for the main motor of the knitting or hosiery machine is preferably connected with the switch means 125 in such a way that the

motors

101a, 102a and 10112, 1021; are started shortly before the knitting or hosiery machine is started and that the motors 101a, 1tl2a and 101b, 1921: are disconnected before the machine comes to a halt. Such arrangement eliminates idle running or piling up of yarns and requires less attention from an operator because the starting and arresting of the yarn feeding mechanism is fully automatic.

Alternately, the yarn feeding mechanism may comprise a single electric motor (say, the

motor

101a, 102a) and a friction clutch or the like which latter couples the motor ltlla, 102a with the roller 10112.

It is equally possible to utilize slightly conical rollers instead of fully cylindrical rollers ltlla, 10112, and to place the conical rollers at an angle with respect to each other. Furthermore, each of rollers 101a, 1011b may be of such length that it may simultaneously feed and control the tension of two or more yarns.

FIG. 5 illustrates one form of a yarn winding machine which utilizes a feeding mechanism of the type shown in PEG. 1. The feeding mechanism F insures that the yarn is convoluted onto a yarn receiving element 30 in such manner that the tension in each convolution of the yarn package 31 remains the same. The roller 1 of the mechanism F rotates at a peripheral speed of between 1500'- 3000 meters per minute which, at a diameter of 60 mm. or thereabouts, corresponds to about BOO-15,000 rpm. The roller I normally rotates at a peripheral speed higher than the speed at which the yarn 32 must be advanced to the element 30, i.e. there normally exists a certain amount of slippage between the yarn 32 and the peripheral surface of the roller. However, if the tension in the yarn increases, the friction between the peripheral surface of the roller 1 and the yarn 32 also increases so that the roller exerts a more positive feeding action and compensates for the increasing resistance of the yarn to advance toward the yarn receiving element 30. As stated before, the yarn may form less than one, one, or more convolutions about the peripheral surface of the roller 1 and the sensitivity of this roller increases proportionally with the length of yarn 32 in contact therewith as well as with the increasing rotational speed of the roller.

The reasons for variable tension in the yarn 32 are many. If the yarn is wound onto the element 30 under varying tension, the convolutions of the yarn package 31 are also under varying tension which results in nonhomogeneousncss of the yarn package. Consequently, when the yarn is payed out by the element 30, e.g. in a kntting or sewing machine, it must be drawn with variable force which is very undesirable for the reasons already explained 'hereinabove.

As is known, all types of winding machines comprise a series of horizontal or vertical spindles mounted for rotation on a supporting structure called a bed. The means for rotating the spindles may comprise a gear train, belts, rollers or the like which, in turn, are driven by the main drive shaft of the machine. Owing to such rotation of the spindles, the yarn is caused to be wound thereabout, either directly or onto suitable spools, bobbins or the like, and is automatically drawn from a payout or supply reel. In addition, since the yarn must be wound about the spindles in the form of a package whose layers must be arranged in a predetermined manner, each winding machine comprises suitable yarn guides which are reciprocated by suitable cam means so as to deposit the yarn in convolutions and layers of predetermined inclination with respect to the axes about which the spindles rotate. The various types of winding machines are distinguishable by specific yarn guiding assemblies which they utilize. The yarn receiving element may assume the form of a reel which is freely rotatable about a shaft or the convoluted yarn may simply consist of a skein which is formed on the spindle. Alternately, the yarn receiving element may assume the shape of a cupped member which is filled by convolutions of the yarn, or an immovable pin from which the yarn is withdrawn in a substantially radial direction. Still further, the yarn package may be a pirn from which the yarn is drawn in substantially axial direction. Such arrangement is also known as drawing the yarn over the head.

FIG. 5 shows an arrangement which winds the yarn 32 onto a receiving or takeup element in the form of a specific spool 3d whose discs or flanges sea consist of wood, cardboard or paper and whose tubular central portion between the discs 39:: receives the convolutions at a slight inclination with respect to the radial direction. The consecutively formed layers of convolutions 33 are slightly inclined with respect to each other, i.e. they are arranged substantially crosswise. Consequently, the convolutions at the respective longitudinal ends of the tubular central spool portion could not be properly supported were it not for the discs 3tltz.

The yarn 32 is dispersed by a payout reel 34, known as a wift, which supports a source of yarn in the form of a package 35 and which is rotatably mounted in the frame 36 of the winding machine. The wift 34 is caused to rotate due to tension in the yarn 32 when the latter is wound onto the spool 30. It will be readily understood that the wift 34 represents but one form of means for paying out or dispensoing the yarns in a Winding machine and that it may be replaced by any other suitable yarn supporting device. The yarn 32 is led through an eye-shaped guide 3-7 which is fixed to the frame 36, and thereupon about the peripheral surface of the roller 1 forming part of the feeding mechanism P which latter, too, is fixed to the frame 36. The wift 34 and the eye 37 together constitute a retarding means for the yarn. The yarn 32 may form part of a single convolution, a full convolution, or more than one full convolution about the roller 1, and then advances toward the reciprocable guide eye 38 and is finally wound onto the spool 30. The spool is mounted on a horizontal takeup spindle 39 which is jou-rnaled in a stationary bearing 40. The rear end of the spindle 39 carries a bevel gear 41 which meshes with a second bevel gear '42 mounted on the main drive shaft 43 of the winding machine. This shaft also carries a heart cam 44 whose periphery is scanned by a follower roller 45. The follower roller is rotatably mounted in a lever 46 whose lower end is pivoted to the machine frame 36, as at 47, and whose upper end is biased by a spring 7 48 so that the follower roller is permanently urged into contact with the cam 44.

The reciprocable guide eye 38 is connected to a shifting member 49 which is mounted in

stationary bearings

50, 51 and which is reciprocable by a connecting rod 52 articulately connected to the lever 46. In this manner, the heart cam 44 causes the yarn 32 to be uniformly distributed over the tubular central portion of the yarn receiving spool 30. Of course, it will be readily understood that the wift 34 need not necessarily be mounted at a level above the spool 30, and also that the spindle 39 may be vertical, if desired. Moreover, the axial length of the roller 1 which is mounted between the yarn package supporting wift 34 and the guide eye 38 may be such that it may simultaneously feed two or more yarns 32.

FIG. 6 illustrates a pirn winding machine which comprises a series of vertical takeup spindles 53 (only one shown) mounted in the spindle bed 54 and rotatably received in

bearings

55, 56. The spindle 53 is driven by the motor shaft (not shown) through an endless belt 57, and carries a yarn supporting or takeup element in the form of a tube 58 made of paper, cardboard or wood. The yarn package in the form of a pirn 59 has a cylindrical median portion and two conical end portions as is well known in the art. The broken lines 59a indicate the individual layers of the yarn body 59. The yarn 60 is delivered by a supply or payout reel 61 which supports a package 62. This reel 61 is mounted below the level of the bed 54. A stationary eye 63 guides the yarn 60 to the peripheral surface of the roller 1 which forms part of the above-described yarn feeding mechanism F and is fixed to the machine frame 64. The yarn thereupon passes through a rockable or oscillatable yarn guide 65 which controls the arrangement of layers 59a in the yarn pack age 59. The rockable guide 65 is pivoted to a sleeve 66, as at 67, the sleeve being mounted on a threaded spindle 68 which latter is secured to the frame 64. The spindle further carries a threaded nut 69 which is connected with a disc 70. The diameter of this disc is selected in such a Way that its periphery contacts the cylindrical median portion of the pirn 59. The disc 70 is formed With a downwardly extending belt arm 71 whose free end projects into an annular groove in the periphery of the sleeve 66. If the disc 70 rotates, the nut 69 travels about the spindle 68 in upward direction and entrains the sleeve 66. Such rotary movements of the disc 70 are brought about whenever a yarn layer 59a reaches its maximum diameter so that the guide 65 is intermittently lifted by the sleeve 66 which causes the formation of pirn 59. r

The yarn feeding mechanism F compensates for any variations in the tension of yarn 60 between the reel 61 and the spindle 53.

FIG. 7 illustrates a cop winding machine. The yarn supplying or payout element assumes the form of an open cylinder 72 which contains a yarn package 73. The yarn 74 travels in upward direction through a stationary eye 75 and about the periphery of a roller 1 which forms part of the yarn feeding mechanism F. The cylinder 72 is mounted in a stationary bearing 76 carried by the machine frame and is driven by the machine shaft through an endless belt 77. Owing to rotation of the cylinder 72, the yarn 74 is twisted as it passes upwardly toward the feeding mechanism F.

The winding machine of FIG. 7 further comprises a swingable yarn guide 78 which is pivoted to the machine frame, as at 79, and is combined with a swingable lever 80 formed with a pot eye 81. The yarn 74 passes from the mechanism F, through the pot eye 81, and through the swingable guide 78 on its way into a slotted funnelshaped container 82 which is rigidly fixed to the machine frame 83. This takeup spindle 84 extends coaxially through the container 82 and is journaled in bearings 85, 85a. The main drive shaft 86 of the winding machine which, as described hereinabove, drives the cylinder 72 through the belt 77, also rotates the spindle 84 through a driving pulley 87, an endless belt 88 and a. driven pulley 89. The yarn package or cop 90 is wound directly onto the bare spindle 84 and forms a series of conical layers. Owing to the conicity of the funnelshaped container 82, the cop 90 is automatically pushed upwardly and along the spindle 84 until it reaches a desired length.

It will be understood that the yarn feeding mechanism F is equally useful in yarn winding machines different from those shown in FIGS. 5 to 7. Also, and as explained hereinabove, each mechanism F may be formed with a roller of such length that the roller is capable of simultaneously feeding two or more yarns, or each feeding mechanism may comprise two rollers (FIGS. 3 and 4) at least one of which may be of slightly conical contour, if desired.

An important advantage of the improved feeding mechanism is that it is capable of immediately reacting to any changes in tension of the conveyed yarn in contrast to certain known yarn feeding mechanisms which were described hereinabove. The feeding mechanism of my invention may rotate within the range of, say, between 400- 2000 meters per minute and, owing to such high speed, will react immediately and will instantaneously compensate for any changes in the yarn tension. In addition, the feeding mechanism is capable of reacting to very small changes in tension such as could not be detected at all by yarn feeding mechanisms of presently known design. As stated above, the sensitivity of the feeding mechanism is in creased if the yarn forms one full convolution or more than one convolution about the roller 1, i.e. proportionally with the length of contact between the roller 1 and the yarn. It is further possible to drive the roller through suitable belting, cords or the like directly from the main drive shaft of a winding, hosiery, knitting or sewing ma chine, but the arrangement of FIGS. 1, 3 and 4 is preferred because it reduces vibration of the roller. Regardless of whether the roller 1 is driven by an electric motor, whether it forms part of an electric motor, or whether it is driven by belting, cords or in any other way, it may extend the full length of a yarn winding or processing machine so as to simultaneously feed yarns to all needles or to all spindles of the respective machine. Such comparatively long rollers are then preferably supported in suitably spaced bearings whose number and spacing depends upon the overall length of the rollers, i.e. upon the number of spindles in a winding machine, upon the number of needles in a flat knitting machine, and so forth. In a winding machine, the roller of the feeding mechanism is parallel with the spindle bed (i.e. with the part 54 shown in FIG. 6).

The feeding mechanism of my invention is utilized wherever it is likely that the yarn may be subjected to variable tension, i.e. the mechanism is preferably mounted in close proximity of that yarn guide which leads a yarn to the package formed on a spindle in a winding machine. The improved feeding mechanism may be used for winding of all types of yarns, e.g. those made of organic, fully synthetic or partially synthetic material, and even of rubber yarns and the like.

FIG. 8 illustrates a sewing machine in which the yarn feeding mechanism F is utilized in connection with a conventional braking arrangement which imparts to the yarn a predetermined tension on its way to the needle means.

Certain presently utilized yarn brakes comprise two spring-biased dish-shaped substantially discoid members which are mounted face-to-face and receive the yarn therebetween. Any variations in the braking or retarding action are brought about by changing the bias of spring means which acts upon the discoid members.

When the improved yarn feeding mechanism is utilized in connection with a braking arrangement or when the feeding mechanism by itself acts as a braking device, it is rotated in a direction counter to the direction in which the yarn advances toward the needle means. For example, the feeding mechanism may rotate at a peripheral speed of between 200-3060 meters per minute, and its braking action again depends upon the length of contact with the yarn. The tension in the yarn generates proportionally increasing frictional forces which cause the yarn to adhere to the peripheral surface of the roller forming part of the feeding mechanism so that the rollers braking action increases.

Referring now in greater detail to FIG. 8, there is shown a sewing machine in which the feeding mechanism F, acting as a braking device, is shown on a greatly enlarged scale when compared with other components of the sewing machine. The machine comprises a frame 2% which mounts a reciprocable needle bar 2%, the movements of this bar 201 being brought about by a system of eccentrics and/ or cams mounted on the main drive shaft (not shown). The forward end of the needle bar 201 supports a sewing needle 2'92 which latter moves in rhythm with a catcher 293. This catcher is mounted on a bar 2% which is axially shiftable in a bearing 295. The bearing 295 receives a three-dimensional movement from a system of eccentrics (not shown) mounted on the main drive shaft of the sewing machine in a manner well known in the art.

It is assumed that the needle 2&2 must sew together two textile sheets 2%, 267 which are inserted between a pair of intermittently rotating drum-shaped transporting members 2%, 299. The rear transporting member 2% comprises a downwardly extending driving shaft 21% which is rotatable in a bearing sleeve 211. The bearing sleeve 211 is connected with the machine frame 2th) in such a way that the rear transporting member 209 may be swung to a certain extent in a direction to the right, i.e. away from the front transporting member 2%. Such mounting of the member 269 is necessary because it facilitates the insertion of workpieces 2%, 2%7. The front transporting member 263 has an upwardly extending shaft 212 which is rotatable in a bearing 213 but is held against axial movement in the bearing. The upper end of bearing 213 is rigidily connected to a frame member 214. The shaft 212 is intermittently rotated by a perforated endless belt 215 which travels about a first wheel 216 on the shaft 212 and about a second Wheel 217 on a shaft 218. The shaft 218 carries two

swingable arms

219, 220 which receive the wheel 217 therebetween and whose free ends rotatably mount a belt tensioning roller 221; the latter is biased by a helical spring 22-2 and bears against the belt 215 so that the belt is under constant and uniform tension.

The shaft 21S is operatively connected to and rotates with the shaft 2% of the rear transporting member 209 (the connection not shown) and is intermittently rotated with the shaft 218 by an eccentric mounted on the main drive shaft of the sewing machine through a suitable transmission of known design (not shown).

The sewing machine operates as follows:

When the transporting members 288, 2% are at a standstill, the needle 262 is caused to perform a forward stroke and to penetrate the workpieces 206, 2%! which are held by the members 2%, 299. When the needle performs its return stroke, the yarn forms a loop in front of the workpiece 2%7 and the loop is caught by the catcher 2% to be deflected over the edges of the workpieces to the exposed side of the workpiece 2M so that the needle 202 may pass through the loop when it performs the next working stroke and again penetrates the workpieces. While the needle passes above the peripheral zones of the transporting members 208, 299 which engage and hold the workpieces 2%, 207, the transporting members are caused to perform an angular movement so as to advance the workpieces, the extent of such angular movement corresponding to the desired length of stitches to be formed in the workpieces.

For the sake of simplicity, the FIG. 8 illustrates a sewing machine of the type which forms a single row of stitches. The yarn 223 is delivered by a supply spool 224 and passes between the adjacent end faces of two

dishshaped braking discs

225, 226 which are mounted on a bolt 227 and are biased by a helical spring 228 so that they may exert a controllable braking force upon the yarn 223. The tension of the spring is adjustable by a knurled knob 229 which is screwed onto the threaded end portion of the bolt 227.

The tension produced by the

braking discs

225, 226 in the yarn 223 varies when the sewing machine is in operation. The exact control of such tension is particularly important when the needle 202 performs a return stroke to tighten the last stitch formed in the workpieces 206, 207. The more tight the stitches formed in the workpieces, the greater must be the tension produced in the yarn by the

braking discs

225, 226. However, the

discs

225, 226 subject the yarn 223 to the same tension throughout the sewing operation, i.e. in all phases of stitch formation in the workpieces. The purpose of the additional braking device in the form of the aforedescribed yarn feeding mechanism F is to vary the tension in the yarn 223 in a fully automatic way so that the tension will reach a desired magnitude in each phase of stitch formation. The mechanism F is located between the

discs

225, 226 and the needle 202, and is mounted on a bracket 230 which is carried by the frame member 214. It is assumed that the yarn 223 forms a single convolution about the peripheral surface of the roller 1. As is indicated by the arrow 231, the roller 1 rotates in a direction counter to the direction of yarn advance, i.e. counter to the direction in which the yarn moves toward the needle 202 (arrow 232). When the sewing machine utilizes such a mechanism F, the

braking device

225, 226 may be omitted altogether.

If the sewing machine is of the type which utilizes two or more yarns simultaneously, it must comprise two mechanisms F or the roller 1 must be of such length that it can simultaneously control the tension in two or more yarns. The improved feeding mechanism, here acting as a brake, is particularly useful in rapidly operating commercial sewing machines used in the garment industry. The roller 1 insures smooth transition from one yarn tension to a different yarn tension; its braking action depends on its diameter, on its rotational speed, and on the length of contact between its peripheral surface and the yarn 223, and may be varied by changing any of these three factors.

P16. 9 is a diagrammatic view of a modified sewing machine which utilizes two yarn feeding mechanisms F and F the first of which acts as a braking device in the manner as described in connection with FIG. 8 and the second of which acts as a yarn advancing device in the manner disclosed in connection with FIGS. 2-7. The mechanism F is mounted between the braking device F and a supply spool 224; its purpose is to prevent any fluctuations in tension of the yarn 223 as the latter advances toward the braking device. Such fluctuations develop as a result of non-uniform winding onto the spool 224 or as a result of imperfections in the yarn. When the tension in the yarn payed out by the spool 224 (arrow 232) increases, the feeding mechanism F will produce a stronger feeding action because the friction between the peripheral surface of its roller 1 and the yarn 223 increases. Of course, it is possible to lead two or more yarns about the roller of the feeding mechanism F and about the roller of the braking device F i.e. to provide the sewing machine with two elongated parallel rollers 1, one of which rotates in the direction of the arrow 231 (braking) and the other of which rotates in the direction indicated by the arrow 233 (feeding).

On its way to the sewing needle 202, the yarn passes through an eye 234, about the roller of the feeding mechanism F about the roller of the braking device F and through a second eye 235 which latter forms part of a deflecting system 236. When the deflecting system moves into the position 236', it causes simultaneous shifting of the eye 235 into the phantom-line position 235', so that the yarn 223 is subjected to a greater tension which brings about a stronger braking action by the roller of the device F This device then delivers yarn at a reduced speed or arrests the yarn at a selected stage of the sewing operation. When the yarn tension is normal, the feeding mechanism F advances the yarn at a requisite rate to the needle 202.

Depending upon whether the braking device F permits the advance of yarn 223 at a faster or slower rate or arrests the yarn altogether, the feeding mechanism F advances the yarn at the required speed, that is, its operation is synchronized with the operation of the braking device. Thus, the tension in the yarn portion extending between the roller of the braking device F and the supply spool 224 is always the same. If the tension of yarn between the braking device and the spool would tend to increase, e.g. owing to improper formation of yarn convolutions on the spool, the feeding mechanism F immediately eliminates undesirable tension in that portion of the yarn which travels toward the roller of the braking device F because the yarn adheres to the roller 1 of the feeding mechanism with a greater force and the feeding mechanism produces a more positive advancing action in the direction of the arrow 232. In other words, the feeding mechanism insures that the yarn 223 reaches the roller of the braking device at constant and uniform tension.

According to a slight modification of my invention, the eye 235 may remain stationary if the movements of the needle 202 can insure requisite tension in the yarn 223 at a point between the braking device and the needle. It is further possible to omit the braking device and to utilize a

conventional braking assembly

225, 226 together with the feeding mechanism F Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic and specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be secured by Letters Patent is:

1. In a textile machine, a feeding mechanism for moving a pair of yarns in predetermined directions and at predetermined constant speeds against variable resistance which the yarns offer to such movements, said mechanism comprising a rotary engine including a pair of coaxial electric motors each of which comprises a rotor, said rotors having smooth peripheral surfaces of tempered hardness, each of said surfaces engaging one of the yarns along at least a portion thereof, and said motors being adapted to drive the respective rotors at such peripheral speeds and in such directions that the peripheral speeds of the rotors exceed said predetermined speeds and that said rotors feed the respective yarns by friction in said predetermined directions whereby slippage occurs between the yarns and the respective surfaces, the peripheral speeds of said surfaces and the friction between said surfaces and the respective yarns being correlated with the resistance which the yarns offer in such a way that the yarns moving in said predetermined directions advance at said predetermined speeds.

2. In a textile machine, a yarn feeding mechanism for moving a yarn in a predetermined direction and at a predetermined constant speed against variable resistance which the yarn offers to such movement, said mechanism comprising a rotary element having a smooth peripheral surface of tempered hardness, said surface engaging the yarn along at least a portion thereof, and drive means for rotating said element at such peripheral speed and in such direction that the peripheral speed of said surface exceeds said predetermined speed and that the element feeds the yarn by friction in said predetermined direction whereby slippage occurs between the yarn and said surface, the peripheral speed of said surface and the friction between the yarn and said surface being correlated with the resistance which the yarn offers in such a way that the yarn moving in said predetermined direction advances at said predetermined speed, said drive means and said element together constituting an electric motor and said element constituting the rotor of said motor.

3. In a textile machine, in combination, yarn receiving means adapted to take up a yarn at a predetermined constant speed; a yarn dispensing arrangement comprising a source of yarn and retarding means adapted to resist withdrawal of yarn from said source with a predetermined force; and feeding means for withdrawing the yarn from said source and for advancing the yarn to said dispensing arrangement, said feeding means comprising an electric motor including a stator and a rotor, said rotor surrounding and being directly coupled with said stator and having a smooth peripheral surface engaging the yarn along at least a portion thereof so that, when the motor is started, the rotor withdraws yarn from said source and feeds it to said receiving means owing to friction which develops between the yarn and said surface, said motor being adapted to drive the rotor at a peripheral speed which is substantially higher than said predetermined speed and which is correlated to said predetermined force and to the friction between the yarn and said surface in such a manner that said rotor withdraws the yarn from said source at said predetermined speed.

4. In a textile machine, in combination, yarn receiving means adapted to take up a yarn at a predetermined constant speed; a source of yarn; retarding means adapted to resist withdrawal of yarn from said source with variable force; and feeding means for moving the yarn from said retarding means to said receiving means and comprising an electric motor having a rotor provided with a smooth peripheral surface of tempered hardness around which at least one convolution of the yarn withdrawn from said source is wound, and a stator directly coupled with and driving the rotor at a constant peripheral speed exceeding said predetermined speed and in such direction that the rotor advances the yarn toward said receiving means whereby said peripheral surface advances the yarn by friction but with substantial slippage, the peripheral speed and the smoothness of said surface being such that, in response to increasing or decreasing force of said retarding means; friction between the yarn and said surface respectively increases and decreases sufficiently to insure that the yarn advances toward said receiving means at said predetermined speed.

5. A combination as set forth in claim 4, wherein the peripheral speed of said rotor is a multiple of said predetermined speed.

6. A combination as set forth in claim 5, wherein said rotor is driven at a peripheral speed of 1500-3000 meters per minute.

7. In a sewing machine, in combination, means for advancing a yarn in a first direction; and a braking device for the yarn, said braking device comprising an electric motor including a rotor adapted to rotate at a high speed in a second direction counter to said first direction and having a dead-smooth peripheral surface of tempered hardness, the yarn being convoluted about and being in frictional engagement with said peripheral surface whereby said surface tends to oppose the advance of yarn in said first direction.

8. In a sewing machine, in combination, needle means; means for advancing a yarn toward said needle means, said advancing means comprising a feeding mechanism including a first electric motor comprising a rotor adapted to rotate at high speeds; and a braking device disposed between said needle means and said advancing means, said braking device comprising a second electric motor including a rotor adapted to rotate at high speeds in a direction counter to the direction of said first mentioned rotor having a dead-smooth peripheral surface of tempered hardness, the yarn being convoluted about and being in frictional engagement with each of said surfaces whereby the rotor of said braking device tends to oppose the advance of the yarn toward said needle means.

9. In a sewing machine, in combination, needle means; means for advancing a yarn toward said needle means, said advancing means comprising a feeding mechanism including a first electric motor comprising a rotor adapted to rotate at high speeds; and a braking device disposed between said needle means and said advancing means, said braking device comprising 'a second electric motor including a rotor adapted to rotate at high speeds in a direction counter to the direction of said first mentioned rotor, each said rotor having a dead-smooth peripheral surface of tempered hardness and the yarn being convoluted about and being in frictional engagement with each of said surfaces whereby the rotor of said braking device tends to oppose the advance of yarn toward said needle means.

10. In a sewing machine, in combination, means for advancing a yarn in a first direction; and a braking device for the yarn, said braking device consisting of an electric motor having a roller-shaped rotor adapted to rotate at a high speed in a second direction counter to said first direction, said rotor having a dead-smooth peripheral surface of tempered hardness, the yarn being convoluted about and being in frictional engagement with said surface whereby the rotor tends to oppose the advance of yarn in said first direction.

11. In a sewing machine, in combination, needle means; means for advancing a yarn toward said needle means, said advancing means comprising a feeding mechanism consisting of an electric motor having a rollershaped rotor formed with a dead-smooth peripheral surface of tempered hardness adapted to receive at least one convolution of the yarn, said rotor adapted to be rotated at high speeds in a direction to advance the yarn; and a 14 brakingdevice disposed rearwardly of said advancing means as seen in the direction in which the yarn advances, said braking device consisting of an electric motor having a roller-shaped rotor formed with a dead-smooth peripheral surface of tempered hardness, the yarn being convoluted about and being in frictional engagement with the surface of said last mentioned rotor whereby said last mentioned rotor tends to oppose the advance of the yarn toward said needle means.

12. In a sewing machine, in combination, means for advancing a plurality of yarns in a first direction; and a braking device for each yarn, each braking device comprising an electric motor including rotor means adapted to rotate at high speed in a second direction counter to said first direction and each of said rotor means having a deadsmooth peripheral surface of tempered hardness, each yarn being convoluted about and being in frictional engagement with the surface of the respective rotor means whereby said rotor means tend to oppose the advance of yarns in said first direction.

References Cited in the file of this patent UNITED STATES PATENTS 2,223,914 Karns Dec. 3, 1940 2,227,355 Lawson Dec. 31, 1940 2,227,356 Lawson Dec. 31, 1940 2,284,244 Allquist May 26, 1942 2,537,000 Stibbe et a1. Jan. 2, 1951 2,656,126 Kinsgbury et al. Oct. 20, "1953 2,744,399 West May 8, 1956 2,746,410 Rassons May 22, 1956 2,802,957 Gievers Aug. 13, 1957 2,826,939 Dever Mar. 18, 1958 2,899,199 Stobb Aug. 11, 1959 2,950,067 Keith Aug. 23, 1960 2,964,251 Samuels et a1. Dec. 13, 1960 2,972,439 Cunningham et a1 Feb. 21, 196 1