US2949756A - Yarn furnisher for knitting machines - Google Patents

Description

Aug. 23, 1960 cu s 2,949,756

YARN FURNISHEIR FOR KNITTING MACHINES Filed May 8, 1957 4 Sheets-Sheet 1 //7l/8/7 for v HoraceL. Cuff/'5 H By his afforneys 1960 H. L. CURTIS 2,949,756

YARN FURNISHER FOR KNITTING MACHINES Filed May 1957 4 Sheets-Sheet. 2

, Horace L Curf/s By his affomeys 1950 H. 1.. CURTIS 2,949,756

YARN FURNISHER FOR KNITTING MACHINES Filed May 8, 1957 4 Sheets-Sheet 3 Haroce L. Cur/1's By his af/omeys Aug. 23, 1960 H. L. CURTIS 2,949,756

YARN FURNISHER FOR KNITTING MACHINES Filed May 8, 1957 4 Sheets-Sheet 4 //7 van I r Horace L. Curr/s By his aflomeys MMJM YARN FURNISHER FOR KNITTING MACHINES Horace L. Curtis, Gilford, N.H., assignor to Scott & Williams, Incorporated, Laconia, N.H., a corporation of Massachusetts Filed May 8, 1957, Ser. No. 657,835

3 Claims. (Cl. 66-132) This invention relates to a yarn furnisher for a knitting machine and more particularly to one adapted to furnish yarn at a constant yarn tension despite variations in drag on the yarn coming from the supply or variations in the yarn demand from the knitting machine.

In knitting seamless hosiery on fine gauge circular machines it is often quite important that the nylon or other yarn be fed to the needles under a uniform but light tension. If this is not done with considerable uniformity horizontal bands of stitches will appear which vary in length from band to band. One cause of variation in the tension of the yarn is faulty winding of the yarn on the pirn, cone or other supply from which the yarn is being drawn. When using yarn furnishers, to overcome this, a compensating type of yarn furnisher is required. With this type of furnisher it is very diflicult to start and stop the yarn fast enough when an automatic yarn change takes place during the knitting. Thus when a yarn finger drops into action or is suddenly lifted out of action the sudden start or stop of the yarn demand of the machine makes it hard for a compensating yarn furnisher to follow with sufiicient rapidity to avoid objectionable changes in tension of the yarn going to the knitting machine. It is the object of the present invention to produce a compensating yarn furnisher which will furnish yarn to the needles at a uniform rate in accordance with the demand despite variations in the drag on the yarn from the supply or sudden stops and starts in the machine demand. It is characteristic of my invention that there is a rotating inverted conical member Whose axis is substantially vertical and around which the yarn to be furnished is wrapped, and a travelling guide responsive to gravity through which the yarn passes as it leaves the conical member to drag the yarn off and back onto the conical member to stop and start furnishing promptly.

In the drawings Fig. 1 is a side elevation of a simple embodiment of my invention showning yarn being furnished to the needles and the dash lines showing the position of the yarn when the yarn finger is out of action.

Fig. 2 is a view of the conical member, the rest and the yarn of Fig. 1 at the moment that the travelling guide has dragged the yarn down to idle position.

Fig. 3 is another view of the same parts as Fig. 2 showing the situation just after the knitting machine has resumed demanding yarn and the travelling guide is dragging the yarn up onto the rotating conical member.

Fig. 4 is a view in elevation on an enlarged scale of the travelling guide of Figs. 1, 2 and 3 on its slide rail when the knitting machine is drawing yarn.

Fig. 5 is a view similar to Fig. 4 but viewing the guide from the right instead of from the front as it appears in Fig. 1.

Fig. 6 is a plan view of the guide of Figs. 4 and 5.

Fig. 7 is a view in elevation similar to Fig. 1 but of a preferred embodiment of the invention in which the yarn Patented Aug. 23, 1960 is wrapped twice around the rotating conical member and the lower end of that member has spiral grooves.

Fig. 8 is a view on an enlarged scale of the guide, the yarn and a portion of the conical member of Fig. 7 showing how the yarn iswrapped around the conical member.

Fig. 9 is a view from the bottom of the rotating conical member of Fig. 7.

Figs. 10 and 11 are enlarged views of the conical memher and slider of Figs. 7, 8 and 9 showing the relation of the yarn and the grooves of the conical member when yarn demand ceases and begins. Fig. 10 shows the relation immediately after the machine demand for yarn has ceased and the guide is dragging the yarn down onto the rest below the conical member, while Fig. 11 shows the situation when the demand has suddenly begun and the guide is starting to drag the yarn upward.

Referring first to the embodiment of Figs. 1 to 6, the yarn supply shown in Fig. 1 is a cone 1, the yarn 2 coming off the cone, passes through a disk tensioning means 3 which supplies a light tension, an eye 4, and then moves horizontally to the compensating cone yarn furnisher of my invention. There should be a substantial distance between the eye above the cone 1 and the slide or travelling yarn guide 17 hereinafter referred to. When the yarn emerges coming from my yarn furnisher, it passes downwardly through another guide eye 5 into a pivoted yarn finger 6 and thence to the needles 7 of the machine as shown in Fig. 1.

The yarn furnisher itself can be a self-contained unit of great simplicity. It can be mounted on a constant speed continuously running electric motor 8, the furnisher itself being carried on a platform 9 above the motor. The platform is larger than the rotating member on it. On the center of this platform 9 is a non-rotating or stationary yarn rest 10. It is preferably made of polished metal and tapered slightly, the upper end being a little smaller than the lower end of the rotating element about to be described. Projecting upwardly part way through the center of the yarn rest is the stub end 11 of the shaft of the motor 8. Carried on this stub shaft is the principal member of my yarn furnisher. This is the rotating conical member designated generally in the drawings by the reference character 12. It is of an inverted conical shape with an axis extending centrally of the cone from its apex being in the vertical direction. Specifically it is an inverted frustum of a cone. The cone is adapted to be rotated continuously at a constant speed by the motor 8 through the intermediary of a hollow socket 13 extending downwardly below, and engaging the main portion of the rotating conical member with the stub shaft 11. The surface 14 of this main rotating conical member 12 is made of rubber or other material having some gripping or adhesive quality for knitting yarns. The rotating conical member can be hollow as shown in Fig. 1 if desired. The lower end of the conical member overlaps the yarn rest 10. The lower end of the conical member 12 can be made of polished metal 39 for a distance of say three quarters of an inch to one inch if desired. There are four or more yarn pick-up lips 15 extending downwardly and outwardly from the lower end at points preferably spaced equally around the member. These lips are shaped and polished to enable the yarn to drop down over them freely as well as to avoid snagging when a yarn is being carried upward. These lips help to bring the yarn back into action as will be explained later. Mounted on the platform 9 near its edge on a line between the yarn supply 1 and the conical member 12 is a vertical guide rod or rail 16. It extends upwardly to a point above the rotating conical member 12. Riding freely on this rod, and

therefore alfected by gravity, is a rider or travelling yarn guide 17. This travelling yarn guide performs several functions. It serves to guide the yarn from the supply onto the conical member. It also takes the yarn from the conical member and directs it onward in its trip to the needles of the knitting machine. It further varies the position of the yarn on the conical member in accordance with the demand of the machine for yarn. The amount of yarn furnished varies according to the diameter of the conical member at the level where the guide is momentarily located. In addition to these functions, the travelling guide plays a part in cooperation with the yarn rest and the lips in facilitating the moving of the yarn into and out of action as shown in Figs. 2 and 3 of the drawings.

The guide 17 is constructed with loops 18 at its top and bottom encircling the guide rod 16 but permitting it to slide freely thereon. Connecting these loops 18 is the body 19 extending out to one side of the road (See Figs. 5 and 6.) There is a horizontal hole 20 extending through the middle of the body 19, this serving to pass the yarn from the yarn supply to the conical member. In addition there is a vertical hole 21 in the body preferably not connected to the horizontal hole 20. The yarn coming from the conical member enters this hole 21 at the bottom and exits from the top. Upon leaving the guide the yarn goes up toward the top of the guide rod 16 where it passes through an eye 22 carried by the rail 16 and thence to eyelet 5 and yarn finger 6.

When the yarn finger is down in the solid line showing of Fig. 1 it is feeding yarn to the needles 7. The solid line showing of the yarn and the arrows by it in this figure will make clear the action of the yarn 2 when being fed. It comes from the yarn supply 1 through the disk tension 3 and horizontal-1y straight across to the guide 17. Here it passes through the horizontal hole 20 in the body 19 of the guide. Thence it goes around the back of the frustum or conical member 12 as viewed in Fig. 1 and around to the front in the direction of rotation of the member 12 as shown by the curved arrow. The surface 14 of the conical member gives the yarn 2 a tendency to adhere thereto and therefore it is not until the yarn leaves the cone that it starts to bend down at point 23 to the bottom of the guide. (See Fig. 1.)

The operation of the embodiment of Figs. 1 to 6 is as follows: The yarn 2 comes from the supply 1 under a light drag due to the disk tensioning means 3. Thence it passes through the stationary yarn guide 4 which is at the approximate average level of the travelling guide 17 when the knitting machine is demanding yarn. This average elevation is the net result or position of equilibrium between the pull of gravity and the upward pull on the yarn due to the machines demand for yarn. The yarn goes straight through the horizontal hole 20 in the body 19 of the travelling guide and starts its wrap around the coming-on side of the conical surface 14. The portion of yarn on this side of the cone is identified by the number 24 in Fig. 1. Thence it goes to the coming-off side which is the one toward the observer in Fig. 1. This portion of the yarn is identified by the number 25. At point 23 where it breaks contact with the surface 14 of the cone 12 it makes any slight bend necessary to aim toward the bottom of the vertical hole 21 in the guide 17. Thence the yarn turns upwardly through the hole 21 to the top of the vertical guide rod 16 where it is threaded through the eye 22 at the top of the rod. At this point the yarn is shown turning toward the stationary eye 5, pivoted yarn finger 6 and needles 7. If the knitting operation requires more yarn the pull on the yarn will raise the travelling guide 17 to a higher level and the frustum of the rotating member 12 will deliver more yarn. If the needles absorb less yarn the travelling guide will drop to a lower level and less yarn will be delivered.

I will now describe how the above coordination fits in with the necessity of rapid cessation and resumption of yarn feeding when the yarn finger 6 goes out of or into action. When the yarn finger 6 is pivoted upward out of feeding position, the demand for yarn ceases instantly and with it the vertical upward pull on the travelling guide. The parts are now in the solid line position of Fig. 2. Note the relaxing of yarn on the conical member. The weight of the guide then causes it to drop to the bottom of the rail 16, leaving the parts in the dotted position of Fig. 2. Immediately thereafter the end of the yarn loop away from the travelling guide falls off the conical member 12 entirely and lies at a standstill, looped around the yarn rest 10 below the frustum. The yarn is now in the dotted position of Fig. 1 and completely idle.

When the yarn finger 6 drops back into action the sudden demand for yarn not only draws on the slack yarn around the rest but lifts the travelling guide upward. Immediately the loop of inactive yarn is carried upward to the point where it is booked by one of the yarn pick-up lips 15 on the bottom of the cone (see Fig. 3). This lip guides it up onto the end of the cone, thus transferring it from the stationary yarn rest to the revolving cone. The continuing demand for yarn continues to lift the travelling yarn guide, which, in turn, continues to feed the yarn upward on the surface of the friction cone until it reaches a point Where the surface speed of the cone equals the yarn demand speed of the knitting machine. At this point equilibrium is established. It will be seen that the furnisher is adapted to maintain a constant yarn tension even though the speed of the yarn passing through the yarn finger 6 varies ac cording to the demands of fashioning or varying machine speed.

The tension device 3 can be set to provide a minimum of tension on the yarn moving toward the rotating conical member 12. This may be as little as 2. or 3 grams. It has been found that under certain circumstances additional traction of the conical member on the yarn is desirable and the preferred construction to use in such a case is shown in Figs. 7 to 11. The additional traction is obtained by wrapping the yarn around the cone or frustum of the conical member twice. It is found that by this arrangement no amount of irregularity or jerking in the manner in which the yarn comes off the cone supply 1 is transmitted to the knitting point. It has also been found that an increase in tension from, say 1 to 10 grams on the supply side of the cone will only cause an increase of from 1 to only 1% grams at most on the discharge side. With this preferred construction the yarn is normally furnished with a tension of 1 gram. In this connection it is noted that the cone runs at full speed continuously and that the vertically movable yarn guide is very light.

In Fig. 7 of the drawings the yarn coming from the yarn supply enters the travelling guide 26 through a horizontal hole 27 which is somewhat larger than the similar hole in the guide of the embodiment of Figs. 1 to 6. The first turn of yarn coming from the supply cone which is located on the coming-on side of the cone is identified in the drawings by the reference character 28. By the phrase coming-on is meant the coming of the yarn onto the inverted revolving cone. The first turn of yarn on the coming-off side, i.e., where the yarn comes off the cone again, is identified in the drawings by the reference character 30. From this first turn 30 on the coming-01f side the yarn re-enters the horizontal hole 27 and emerges again to form the second turn 29 of yarn on the coming-on side and the second turn 31 of yarn on the coming-off side. It has been noted that there is a tendency for the two wrappings of the yarn around the cone to support each other slightly in the vertical dimension.

As previously intimated, a fast out and in of the yarn when the machine demand for yarn ceases or begins again is very valuable and I will now describe the features of the preferred embodiment of Figs. 7 to 11 directed to this aspect. In the first place there is a circle of spiral grooves 32 on the lower end of the drawing member, i.e., the revolving conical member, and these spiral grooves revolve with the rest of the member. The grooves are so inclined as to assist in the fast out and in of the yarn in an ingenious manner. This out and in feature is intimately involved with certain other aspects of the construction. It will be observed in the drawing that the grooves are inclined all in one direction and in the embodiment shown in the drawings where the direction of rotation of the frustum is indicated by the horizontal arrows, the lower ends of the grooves are ahead of the upper ends in the direction of rotation. In other words, the grooves are pitched backward when considered from bottom to top. This by itself is not enough to achieve the fast out and in but taken with the difference between the feeding on and feeding ofi sides and the relative tensions of the yarns from the supply and from the knitting part at the ceasing and commencing of the yarn demand by the knitting machine, I have a correlation which gives me the desired action.

At the bottom of the slanted flutes on the lower end of the frustum, the member is scalloped so as to produce points 33 facing downwardly. The vertical guide rail 34 provided in the same location as the guide rail 16 of Figs. 1 to 6 has at its top a sensitive shock absorbing tension spring 36 on which is carried a guide eye 35. The yarn in the travelling guide 26 passes upwardly to its eye 35 and thence to the yarn finger and needle as heretofore. Acting as a limit stop through the movements of the travelling guide and the eye carried by the tension spring 36 is a separator or limit stop 37 (see Figs. 10 and 11 It will be noted that owing to the presence of disk tension 3 near the cone supply 1 the foot-long strip of the yarn 2 coming to the travelling guide 27 is under a low but uniform tension at all times. Therefore the portions 28 and 29 of the yarn on the coming-on side are drawn against the frustum. When the yarn demand of the machine ceases, the equilibrium between gravity and the upward pull of the yarn on the traveling guide is upset and the guide drops, dragging down with it the portions of the yarn which are passing through it at that moment. This brings the portions of the two loops around the frustum which are nearest to the guide down to a position below the grooves 32. However, on the coming-on side of the frustum, the grooves are sloping downward to the right as viewed in Fig. 7, while the portions of the yarn over them are sloping downward to the left under the conditions set forth. Therefore, the yarns are lying across the grooves rather than in them. As a result the grooves cannot possibly grasp the yarn. Since the grooves cannot interfere with the dropping of the guide and the material of the grooves is polished, the yarn slips off the frustum and the grooves down on to the rest it? without any delay.

Turning now to the coming-01f side we find the following situation: The grooves 32 and the turns 30 and 31 of yarn on the coming-off side are practically parallel and one might think that the yarn would get into the grooves and cause the loops to be thrown back up onto the frustum. I have found, however, that because the machine demand for yam has ceased and the yarn finger raised, the yarn between the yarn finger 6 and the traveling guide is relatively slack in spite of the dropping of the guide. This slackness transmits itself to the turns 30 and 31 of the yarn on the coming-off side suificiently so that the yarn is slack enough not to get caught in the grooves. The entire loops therefore are first pulled down by the guide until the left side of the loop is off the frustum and immediately thereafter the right side of the loop drops down. This operation occurs with the speed of the gravity movement of the traveling guide 26.

I will now explain how this construction works automatically in exactly the opposite manner when the machine begins to demand yarn again.

Assuming that the two loops of yarn around the rest 10 are in fixed position with the traveling guide 26 opposite the rest in somewhat the same manner as the yarn in dotted position of Fig. 1, a resumption of, demand of yarn stretches the tension spring 36 and brings the traveling guide 26 up to the position shown in Fig. ll. This occurs very rapidly of course and immediately thereafter the whirling points 33 at the bottom of the grooves 32 pick up the yarn and lift it off the stationary member or rest 10, on to the revolving flutes. Up to this moment the demand for yarn has been supplied by the rising of the traveling guide and the stretching of spring 36. The portions 30 and 31 of the yarn on the comingoff side are at right angles to, i.e., lie loosely across the flutes. However, on the coming'on side the yarn now lies in the flutes and is lifted up. Thus it will be seen that the leading action of the traveling guide 26 produces an angle in the wrappings of the yarn around the revolving member which, when taken in connection with the relative slackness and tautness of the loops on the leading-on and leading-off sides enables the apparatus to give prompt stoppage and prompt resumption of the yarnfurnishing operation.

What is claimed is:

l. A yarn furnisher for a circular knitting machine comprising a yarn supply, a constantly rotated inverted conical member with a substantially vertical axis and around which the yarn from the supply is wrapped, a traveling yarn guide beside the conical member, subject to the pull of gravity adapted to present yarn to the conical member from the yarn supply and to receive it back from the conical member after the yarn has passed therearound, in combination with a guide eye above the yarn guide to receive the yarn going to the knitting machine from the guide and to present the yarn demand to the guide in opposition to gravity, a non-rotatable rest in position below the conical member adapted to receive any yarn dropped by the latter, and a series of spiral grooves on the lower end of the conical member revolving therewith, said grooves being so inclined that when the yarn demand stops, the guide drops below the spiral grooves, the yarn coming from the yarn supply to the conical member is crossways of the grooves and drops below the grooves, and when the yarn demand begins and raises the guide, the grooves engage the yarn and speed it to a position on the conical member.

2. A yarn furnisher for a circular knitting machine comprising a drawing member which is an inverted frustum with a substantially vertical axis and adapted to be rotated at a constant speed, the surface of the inverted frustum being capable of drawing yarn at a rate dictated by the point of contact of the yarn with such surface, a guide movable along a path substantially parallel with the drawing member, said guide being adapted to drag the yarn below or up toward the frustum surface when the yarn demand of the machine ceases or begins, there being a series of spiral grooves on the lower end of the drawing member and revolving therewith, and a yarn supply whose yarn comes through the guide onto the frustum on one side of the latter and comes off the frustum to the guide and the knitting machine on the other side, the grooves being so inclined that when the guide drops because yarn demand ceases, the yarn on the coming-on side is crossways of the grooves and will not catch in the grooves, While when the yarn demand begins and raises the guide the yarn on the coming-on side lies in the grooves and is raised by them onto the drawing surface of the frustum.

3. A yarn furnisher for a knitting machine comprising a constantly rotatable inverted conical member whose axis is substantially vertical and around which the yarn to be furnished is wrapped, the surface of the member being capable of drawing yarn without slippage, a nonrotatable rest below the conical member adapted to receive any yarn dropped'by the rotatable member, in combination with a gravity guide threaded on the yarn where it comes to and leaves the conical member, said guide being movable vertically between the conical member and the rest in accordance with yarn, demand in combination with an eyelet through which the yarn passes from the guide on its way to the knitting machine and tension means tending to pull the eyelet away from the guide, gravity tending to pull the guide away from the eyelet and to drag the yarn down onto the rest when yarn demand ceases; whereby the commencement of yarn demand not only moves the eyelet toward the guide to give a momentary yarn supply but lifts the guide both to supply more momentary yarn and to start the regular yarn feed from the conical member.

References Cited in the file of this patent UNITED STATES PATENTS 1,853,020 Page Apr. 5, 1932 2,667,052 Lebocey Jan. 26, 1954 FOREIGN PATENTS 331,155 Germany Dec. 31, 1920 921,279 Germany Dec. 13, 1954 935,061 France Ian. 19, 1948

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