US3566621A - Arrangement for positive yarn tension control on double row warp knitting machine - Google Patents

Abstract

THE PRESENT ARRANGEMENT IS PARTICULARLY ADAPTED FOR VARYING THE FEED OF SELECTED SETS OR GROUPS OF WARP YARNS DURING THE KNITTING OF TUBULAR FABRIC ON A DOUBLE ROW WARP KNITTING MACHINE. THE SELECTED VARIATION IN THE FEED RATE OF THE WARP YARNS IS PARTICULARLY ADAPTED FOR KNITTING TUBULAR HOSIERY BLANKS WHEREIN A DIFFERENT STITCH PATTERN IS EMPLOYED IN KNITTING THE REINFORCED AND PLAIN KNIT SECTIONS OF THE HOSIERY BLANK.

Description

March 2, 1971 M. A. PERRIER 3,566,621

ARRANGEMENT FOR POSITIVE YARN TENSION CONTROL ON DOUBLE ROW WARP KNITTING MACHINE 4 Sheets-Sheet 1 Filed July 14. 1969 Inventor MARILJS ANTOINE PEREJEE BY flwwfljfizlf, 1%.M9 JM A T702 IVE V5 March 2, 1971 M. A. PERRIER 3,566,621

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Inventor.- Mmams ANTOINE PERRIER BY wzzwwgw wwwm ATTORNEYS United States Patent 0 3,566,621 ARRANGEMENT FOR POSITIVE YARN TENSION CONTROL ON DOUBLE ROW WARP KNITTING MACHINE Marius Antoine Perrier, Lyon, France, assignor to Somarco S.A., Fribourg, Switzerland Filed July 14, 1969, Ser. No. 841,192 Claims priority, application Germany, July 13, 1968, P 17 60 879.6 Int. Cl. D04b 23/02 US. CI. 6687 5 Claims ABSTRACT OF THE DISCLOSURE The present arrangement is particularly adapted for varying the feed of selected sets or groups of warp yarns during the knitting of tubular fabric on a double row warp knitting machine. The selected variation in the feed rate of the warp yarns is particularly adapted for knitting tubular hosiery blanks wherein a different stitch pattern is employed in knitting the reinforced and plain knit sections of the hosiery blank.

This invention relates to an arrangement for the positive continuous take-off of yarn or thread from multiple warp beams of flat warp knitting machines with two needle rows, particularly Raschel knitting machines for knitting seamless hosiery blanks in the form of one or more tubular knitted fabrics. Each tube contains continuous repetitions of the hosiery lengths and is formed in two circumferential halves which are knit on different needle rows. The halves are knit along adjacent portions of the two needle rows and the halves are interknitted and joined together by alternately knitting across and between neighboring needles of the two needle rows. The thread take-off speed of at least one warp beam feeding each needle row is variable in two or more steps to permit the knitting of different stitch patterns of the group of warp yarns. An independent shift gear transmission is provided and the speeds of the warp beams are infinitely readjustable, in accordance with the yarn tension, to compensate for their decreasing diameters.

Contrary to ordinary tubular knitted fabrics, such as for night caps, gas light mantles, or the like, tubular fabrics for ladies hosiery require reinforcements for certain sections which later form the toe, the sole, the heel and the welt of the finished stocking, in order to provide for the special stresses on these parts. One part of these reinforcements, i.e., those for the toe, the sole,- the heel are only needed on one circumferential half of the hosiery tube whereas the part forming the welt is reinforced on the whole circumference of the hose.

Whereas the above-noted prior types of tubular knitted fabrics have been exclusively made on circular knitting machines as weft knitted fabrics, it has been recently suggested in French Pat. 1,321,541 that flat warp knitting machines with two needle rows, among which is in particular the Raschel knitting machine, may be used to knit tubular hosiery fabric blanks. In this type of machine, the alternate interlacing of whole groups of warp yarns on the two needle rows produces the circumferential halves of the hose and thereby yields essentially higher manufacturing performance and reduces the manufacturing cost considerably. By means of the integral knitting of two different kinds of stitch patterns with at least two rows of guide bars on each needle row, run-proof fabric can also be knit.

To manufacture reinforced hose sections, the type of stitch pattern is changed either on one or both needle rows. If two or even more sets of warp yarns are fed to each needle row, it is sufficient to change the type of ice stitch pattern being formed of one of such sets of warp yarns. While the main part of the stockings, particularly the leg length, includes a tricot pattern integrally knit with a plain pattern to form a double yarn stitch loop tricot fabric, the plain pattern is replaced in the reinforced sections by an open or closed twill pattern. The thereby increased thread consumption is compensated for by stepless change of the take-off speed of the respective group of warp yarns by means of a special change gearing which is independent of the drives of all the other warp beams, such as is known from the French Pat. No. 1,488,796. Since the reinforcements are needed for the hose toe on the one circumferential half and for the sole and heel on the other circumferential half while reinforcements are required for the knitted-on welt on the whole hose circumference, at least one warp beam feeding to each needle row has to be separately driven over an independent change gearing which allows the take-off speed to be adapted to the changing type of stitch pattern being knit of the groups of warp yarns being furnished by these warp beams. Further, by means of well-known infinitely variable transmissions which are preferably controlled by the thread tension (Swiss Pat. No. 414,924), the differently decreasing warp beam diameters are compensated for in such a way that the thread take-off speed for a certain type of stitch pattern is kept constant, independently of the effective warp beam diameter.

Despite the most careful setting of the control devices for such infinitely variable transmissions used with two or multi-step change gearings, it is still not possible to obtain sufficiently uniform tension and feed of the yarn in those parts of the hose in which both circumferential halves of the tubular knitted fabric have the same stitch pattern. Even slight deviations yield streaks along the juncture connecting the two circumferential halves, which even visually stays on the finished hose after it has been finally shaped by steam or other heat treatment and thus reduces the market value of the hosiery, even if it does nglt completely ruin it or renders the hosiery unmarketa e.

It is an object of this invention to eliminate such streakingness in the hosiery fabric. To this end, the corresponding independent change gearings of the warp beams corresponding to the two needle rows are preceded by a common infinitely variable transmission which is dependent on the yarn tension of the corresponding groups of warp yarns of these beams. The feeds to the two needle rows and the changes of the shifts of the gear transmissions are correspondingly programmed so that the coordlnation of the two circumferential halves of the tubular knit fabric to the two needle row changes from hose length to hose length.

By changing the coordination of the two hose halves to the two needle rows, the different amounts of thread consumption caused by the unilateral reinforcement feeds on the warp beams engaged in this process, is constantly compensated so that their diameters decrease in a substantially uniform manner. Under these conditions the infinitely varia'ble transmission of such a pair of warp beams maintains an exact conformity of the warp takeoff speed and the same gear ratios of the shift gear transmissions as they have during the knitting of the leg portion of the hose.

In the following, the invention is explained in detail by referring to the drawings, in which- FIG. 1 is a side elevation of a partially reinforced ladies stocking in finished form, illustrating its shape after boarding;

FIG. 2 is a side elevational view of one side of a tubular knitted hosiery blank, from which the stocking of FIG. 1 is formed;

FIG. 3 is a perspective view of the tubular knitted hosiery blank of FIG. 2;

FIG. 4 is a somewhat schematic transverse vertical sectional view of a Raschel knitting machine with two needle rows for making tubular knitted hosiery blanks of the type shown in FIGS. 2 and 3;

FIG. 5 is a fragmentary plan view of the needle beds, schematically illustrating the longitudinal distribution of the latch needles and hold or blind needles adjacent the end areas of each tubular blank;

FIGS. 6-10 show the point diagram for the laying of the yarns and the formation of the stitch patterns in the different hose sections; and

'FIG. 11 is a somewhat schematic view showing the principal drive and control devices for the positively driving of the warp beams of the Raschel knitting machine.

The ladies stocking, broadly indicated at in FIG. 1, includes a reinforced toe 11, sole 12, heel 13 and welt 14 with the reinforced areas being cross-hatched while the upper part of the foot 15 and the leg length 16 remain unreinforced.

The first step in the formation of such a hose includes knitting a hosiery blank, represented as one continuous tubular knit length A (FIG. 2). The upper end of this tubular knit blank is reinforced at a on the two circumferential halves v and h and over the same length to form a turned and hem-med welt 17, on the finished hose, while the bottom section represents different lengths of reinforcements a and 11 on the two circumferential halves v and h. The reinforcement a on the back circumferential half is longer and forms the heel and sole of the finished hose while the shorter reinforcement a on the front circumferential half forms the hose toe after the tubular hosiery blank has been cut along a curved line 18 (FIG. 2) which is adapted to the shape of the foot and stitched at the same time along the curved edges. A comparison between FIGS. 1 and 2 shows the different lengths of formation of the reinforcements a and u while the upper foot part 15 is unreinforced as desired and the stitches are the same as the stitches of the leg length 16.

FIG. 4 shows the general construction of a Raschel knitting machine with two needle rows for simultaneously knitting a plurality of such tubular hosiery blanks as side by-side warp knit fabrics. For example, it is possible to make simultaneously twelve knitted stockings on the same machine. As is known, the Raschel knitting machine is equipped with two rows of active latch needles Z and Z and a number of blind or hold needles, reasons explained later on. Latch needle leads 21 and 22 are located on each side of grooved needle beds 23 and 24 which are fixed on respective needle bars 25, 26, carried by levers 27, 28. The levers 27, 28 swing around the pivots 29, 30 and are driven by push rods 31, 32 and roll guides which are supported on levers 33, 34. Cam discs 37, 38 are fixed on the synchronously driven main shafts 35, 36 of the machine and impart alternate raising and lowering movements to the needle bars 25, 26.

Guide bars I through VIII are supported for lengthwise shifting or shogging movement on spaced supports 39 which are fixed along the length of a guide bar swinging shaft 40, only one of such supports 39 being shown in FIG. 4. The guide bars are provided with yarn guide fingers which swing across the needles by means of a lever 41 and a connector rod 42. A lever 43 is connected to the rod 42 and is provided with a roll guide which rides on a cam disc 44 fixed on the main shaft 35. Swinging movement is thus imparted to the shaft 40 in the proper proportion to the upward and downward movement of the latch needle bars 25, 26. Further, the guide bars separately make the longitudinal shogging movements required for the over and under laying of the yarns to the latch needles, which as is controlled by well-known pattern link chains, not shown, running over a pattern chain drum at one end of the machine. The threads in the form of groups or sets of Warp threads 45, 46, 47, 48 (FIG. 4)

are fed from the four respective warp beams K K K K and over respective thread tension rods 49, '50, 51, 52 and then through the guide fingers located on the eight guide bars I through VIII. The tension rods extend over the total machine length and are supported on the ends of respective levers 53, 54, 55, 56 which are maintained under respective tension springs 57, 58, 59 and 60 so that the warp thread groups running above the rods are kept under flexible tension. The construction of the above-described parts does not differ from that of conventional Raschel knitting machines with two needle rows for knitting fiat ribbed fabrics. Moreover, tubular hosiery blanks are now being knit in a continuous manner on machines with two latch needle rows. However, in all such knitted hose, the halves which form the front circumferential part of the stocking are continuously knit on one latch needle row and all knitted hose halves which form the back circumferential part of the hose are continuously knit on the other latch needle row, the two knitted hose halves being interlaced at the longitudinal edges by alternately placing yarn around neighboring latch needles of the two needle rows.

FIG. 5 schematically represents the covering of the latch needle rows and the locations of the feed fingers on the corresponding guide bars. In each latch needle row Z Z for example, twelve groups of to adjacent needles form longitudinal sections of a length indicated at B which serve for making one tubular knitted hosiery blank. Between these groups of active latch needles, which are shown in full black in FIG. 5, there are some blind or dummy needles, indicated by circles. If desired, the latch needles between the sections B may be left out completely. In corresponding manner, the guide bars I, III, VI and VIII are also provided with yarn guides, as shown by circles on the guide bars, shown as dotted lines. Compared to this, the guide bars II and VII have only one yarn guide 61, 62 and 63, 64 respectively, at the end of each section B. Guide bars IV and V each have only one yarn guide 65, 66 respectively, staggered diametrically to each other and at each end of section B.

FIGS. 6 and 7 show the type of thread lapping, which the eight guide bars carry out during the knitting of the area of the leg length 16 of the stocking 10 and alternately at the front and back latch needle rows at V and H respectively. Supposing that the pattern chain drum on the right side of the machine, with reference to FIG. 5, is located at a link of the pattern chain having a height 0, the guide bars are at the extreme right positions (FIGS. 6 and 7), that is, with reference to FIG. 5 they are at their highest position, and move to the left and downward respectively by one latch needle distance as pattern links with heights 2, 4 and 6 are moved into operative position, as indicated by the corresponding figures 0, 2, 4 and 6 in the FIGS. 5 to 10, which will be presently described. As illustrated in FIG. 6, a closed stitch fabric pattern is formed by the guide fingers of the guide bar I on the front latch needle row Z while the guide fingers of the guide bar III form a tricot stitch pattern integral with this closed stitch fabric and on the same latch needle row Z Thus, integral tricot patterns are knit on the front latch needle row Z In the same way, the guide fingers of the guide bars VIII and VI on the back latch needle row Z lay the corresponding threads to knit integral tricot patterns. This pattern produces a knit fabric which has double yarn stitch loops and has the advantage of being run-proof, even if a warp thread is torn or if there is a hole in the stocking.

The same stitch patterns are also knit along the longitudinal edges b, b at the juncture of the two circumferential sections v and h of the knitted hose by means of guide bars II, IV, V and VII. FIG. 7 illustrates the movement of the guide bars in the same way as the guide bars III and VI form closed stitches alternately around two neighboring needles of the same latch needle row Z and Z respectively. The guide bars IV and V are only equipped with the guide fingers 65 and 66 respectively at the end of each section B and alternately form stitches around the last latch needles 67, 68, 69 and 70 respectively of the two needle rows at the end of each section B and thus also produce a tricot pattern. The guide fingers 61, 62 and 63, 64 respectively of the guide bars II and VII also alternately form endmost stitches around the last active latch needles 67, 68 and 69', 70 respectively and at opposite ends of the needle section and also around the next to last latch needles 71, 72 and 73, 74 respectively. It is obvious that the tubular knit fabric thus produced has the same stitch pattern over the whole circumference as is necessary for the whole leg length 16 of the stocking 10. There are only two other conditions to be met, that is, that the distance between the two latch needle rows must be the same as the needle gauge of each row, and the thread tensions of the warp thread groups fed to the guide bars I, II, VII and VIII and the thread tensions of the individual warp threads fed to the guide bars III, IV, V and VI must be the same.

From the last condition it is seen that the warp beam K does not only supply the warp thread group for the guide bar I, but also the warp threads for the individual guide fingers of the feed rail II. In the same way, not only the threads for the guide fingers of the guide bar VIII are taken off from the warp beam K but also those of the guide bar VII. Further, the warp beam K furnishes not only the guide bar III with the warp thread group but also supplies one warp thread each for each section B to the only guide finger of the guide bar IV. The warp beam K feeds not only the warp thread group to the guide bar VI but also supplies one warp thread each for each section B to the only guide finger of the guide bar V. FIG. 4 shows this coordination of each warp beam to two guide bars, by the divided path of the warp threads 45 through 48 below the thread tnesion rods 49-52.

In order to make the reinforcements a a and a in the tubular knit halves v and h, in accordance with the present invention, the closed stitch shogging patterns of the guide bars I and VIII (covered completely with guide fingers in the sections B) are changed to a twill stitch shogging pattern. As is known, a twill stitch is formed by placing the thread over two latch needles with constant change of placing direction and a single displacement from stitch row to stitch row by the gauge of one needle. While there is only a single placement over the first latch needle, an open or closed stitch is formed on the second latch needle. As the case may be, either an open or a closed twill is formed.

The example of FIGS. 8 to 10 shows the placement of the threads for the formation of open twill. FIG. 8 shows the placement pattern for knitting the bottom part a of the tubular knit section (FIG. 2), where only the front circumferential half v is reinforced. Therefore, the twill is only placed by the guide fingers of the guide bar I.

FIG. 9 shows the placement pattern for knitting the part a of the tubular knit section, where only the back circumferential half h is reinforced, and in which case only the guide fingers of the guide bar VIII place the twill pattern. However, in FIG. 10 both the guide fingers of the guide bar I and the guide bar VIII place the twill pattern and thus simultaneously produce the reinforcements on both circumferential halves of the tubular fabric as they are required, both for the area a, of the welt and the longitudinally overlapped area of the sections a and Compared to this, the tricot placements of the guide bars III and VI remain unchanged in all areas and even on the longitudinal edges b, b of the circumferential halves v, h, the guide bars II, IV, V and VII continue to form the tricot pattern. The thus conditioned deviations of the stitches along the longitudinal juncture of the edges of the two circumferential halves v, h in the area 01 of the welt and in the overlapping area of sections a and a are not objectionable since, when wearing the stockings later, they are covered by the dress or skirt and shoes respectively.

As is quite obvious from a comparison of FIGS. 8 through 10 with FIG. 6, the thread requirements for the guide bars I and VIII to form the twill stitch pattern in the reinforced hose sections is considerably higher than for the closed stitch tricot pattern in the unreinforced section. Therefore, the thread take-off speeds of the warp beams K and K have to be in part individually and in part jointly higher, when knitting the reinforcements than when knitting the unreinforced hose sections. Further, it is indispensible when processing such fine yarns, as are used in the manufacture of hosiery, that the warp beams are driven mechanically, that is, that they work with positive feed thread take-off. This means that the thread take-off speeds of the warp beams K and K must vary by large amounts and independently of each other. On the other hand, within the individual hose sections in which the placements do not change, the thread take-off speeds must be kept constant in order to maintain a constant thread tension, which, because of the decreasing warp beam diameter requires a continuous and gradual or stepless increase of the warp beam speeds.

While the thread take-off speeds of the warp beams K and K remain unchanged, due to the ever constant placements of the warp thread groups supplied by them, and therefore the effective diameter of these warp beams decrease in conformity during the manufacture of each tubular knit section A, the thread requirements on the warp beams K and K are differentially high because of the different lengths of the reinforced areas a and a of the twill stitch pattern, and would actually require an individual readjustment of the speeds of these two warp beams, independently of each other. However, in accordance with this invention, this requirement can be avoided by the fact that the coordination of the tubular knit halves of the front and back sides of the stocking with the front and back needle beds changes from hose length A to hose length A so that the different thread requirements on the warp beams K and K balances again when knitting each second knit section A. Since the decrease in diameters of the warp beams while knitting two of such sections A is extremely low, the diameters of the warp beams K and K practically decrease in conformity and allow a common stepless resetting of their speed.

FIG. 11 shows the driving parts which are required for the positive thread take-off. A sprocket is fixed on the main shaft 35 which drives, through chain 76, a sprocket 77 on an intermediate shaft 78. A gear 79, also located on the intermediate shaft 78, meshes with a gear 80 on the input shaft of an infinitely variable transmission 81, such as a PIV transmission. The output shaft of the infinitely variable transmission 81 drives, through a bevel gear transmission 82, 83, a worm gear transmission 84, 85, and a chain drive 86, 87, 88, the warp beam K The warp beam K is driven through a pair of gears 89, which serves only to reverse the rotary direction, and another chain drive 91, 92, 93. Since the pairs of gears 89, 90 and sprockets 91, 93 have the same meas urements, it is understood that the two intermediate warp beams K and K are synchronously driven in opposite directions.

The speed of the infinitely variable transmission 81 is adjusted by a reversible motor 95 acting through a reducing gear 94. The operation of the motor can be delayed for selected periods by a time relay 96, which is adjustable by a setting button 97. The direction of rotation of the motor 95 depends on which of two limit switches 98, 99 receives an impulse from fingers 100, 101, located on the tension lever shaft 55, when the corresponding thread tension rod (FIG. 4) swings beyond one or the other side of the normal swing range for the desired thread tension. The motor 95 is thereby switched on temporarily and changes the gear ratio of the infinitely variable transmission 81 so that the thread tension lever 7 51 returns to its normal swing size. By the correct regulation of the set button 97, the switch on time of the relay 96 is varied to avoid both an overswinging to the other side of the swing range and a too-frequent switching on of the motor from the same overswing side. Due to the identical diameters of the warp beams K and K and their synchronous drive in connection with the same thread requirements for both warp beams, the thread tension rod 50 (pertinent to the warp beam K in the position of its swing range) always harmonizes with the thread tension rod 51 of the-warp beam K so that all warp threads supplied from these two beams have always the same tension and produce a uniform tricot weave all over the tubular knit circumference.

In accordance with the invention, only one infinitely variable transmission 102 is provided for driving the warp beams K and K with partly different speed. The infinitely variable transmission is driven by the second main shaft 36 of the machine through a chain drive 103, 104, 105 and a pair of gears 106, 107. However, on the output side of the infinitely variable transmission 102, this drive line is on the one hand branched off through bevel gears 108, 109 to a two-step change gear device 110 and on the other hand through a chain drive 111, 112, 113 and a pair of bevel gears 114, 115 to another or second two-step change gear device 116. An output shaft 117 of the change gearing 116 drives, through a worm gear transmission 118, 119 and a chain drive 120, '121, 122, the warp beam K An output shaft 123 of the change gearing 110 drives, through a worm gear transmission 124, 125 and a chain drive 126, 127, 128, the warp beam K The two change gearings 110, 116 are identical and are changed by adjusting devices 129, respectively, which act on respective keys 131, 132. The keys 131, 132 can be shifted between the positions shown to change the rotational speeds of the respective output to the degree required. It is not necessary to comment any further on the design and function of such two-step or two-speed change gearings, since the expert in this technical field is very familiar with them. A suitable speed adjusting device is represented and described for example in French Pat. No. 1,488,796. As a matter of fact, other shift or change gear transmissions with any adjusting devices may be used instead of this gearing, as long as they have the gear ratios required for the individual shift phases and their change can be controlled by the programmer of the machine with the necessary speed.

In order to adjust the infinitely variable transmission 102, as in the case of the infinitely variable gear 81, a reversible motor 133 is provided with reducing gear 134 and, this time, a time relay 139 with control set button 140. The motor 133 is controlled by the lever shaft 56 through fingers 135, 136 and corresponding limit switches 137, 138. The interior control of the timed relay is, for example, described in the U.S.A. patent specification 3,364,403. Other control devices can also be used for the infinitely variable transmissions 81, 102 instead of the respective limit switches 98, 99 and 137, 138 and the respective time relays 96 and 139, if they are suitable to readjust the gear ratios of the infinitely variable transmissions 81, 102 so that thread tension rods 49, 50, 51, 52 are returned to their normal operating area.

The change of gearings 110, 116 is controlled by the programmer of the machine, which in most cases will be formed by a paper tape or cards, and simultaneously with the change of the pattern chains to knit other type of stitch patterns of the warp threads fed from the warp beams K and K In accordance with the invention, the programmer is so programmed that the tubular knit half v of one hose length A (FIGS. 2 and 3) is knit on the front needles Z and the corresponding threads are fed from the first two warp beams K and K Then, the tubular knit half 1 of the next successive hose length A is knit on the rear needles Z and the corresponding threads are fed from the last two warp beams K and K This procedure reverses with the knitting of each successive hose length A so that the different thread take-01f and consumption for each hose length A from the warp beams K and K constantly balances and their effective diameters also decrease uniformly and the tensions of the Warp threads fed from these beams are exactly identical at the same switching position of the change gearings 110, 116, particularly at the switching positions between the knitting of the reinforced sections and the unreinforced leg area 16 of the hose 10.

In the drawings and specification there has been set forth a preferred embodiment of the invention and although specific terms are employed they are used in a generic and descriptive sense only and not for purposes of limitation.

I claim:

1. In a flat warp knitting machine for knitting successively interconnected seamless hosiery blanks having reinforced stitch patterns in selected areas and including front and rear needle rows, a plurality of positively driven warp beams feeding sets of warp threads to said needle rows, and warp thread guide means for feeding the warp threads to said needle rows to form one circumferential half of each hosiery blank on each needle row and to interknit the halves at opposed edges, and wherein one circumferential half of each hosiery blank includes a greater length of the reinforced stitch pattern than the other half so that the knitting of said one half consumes a greater length of the warp threads than the knitting of the other half; the combination therewith of means for uniformly controlling the positive take-off of thread from said warp beams, said control means comprising (a) means for knitting said one half of alternate hosiery blanks of threads fed from certain warp beams while knitting said other half of alternate hosiery blanks of threads fed from other warp beams, and

(b) means for knitting said one half of intervening hosiery blanks of threads fed from said other warp beams while knitting said other half of intervening hosiery blanks of threads fed from said certain warp beams so that the length of threads fed from said certain and said other warp beams is equalized over the period of the knitting of a number of hosiery blanks.

2. A knitting machine according to claim 1 wherein said positive thread take-off means includes change gear transmission means for switching the rotative speed of selected warp beams to increase the speed thereof during the knitting of the reinforced areas of the hosiery blank and to reduce the speed thereof during the knitting of the remaining areas of the hosiery blank.

3. A knitting machine according to claim 2 including infinitely variable transmission gear means drivingly connected to said change gear transmission means, and control means for said infinitely variable transmission gear means for gradually increasing the rotative speed of said selected warp beams as the warp threads are fed therefrom and as the diameters decrease.

4. A knitting machine according to claim 3 wherein said control means includes means operable in response to variations in the tension on the warp threads to adjust said infinitely variable transmission gear means, and time delay relay means preventing the operation of said control means with momentary variations in tension on the Warp threads.

5. A knitting machine according to claim 1 wherein said plurality of warp beams includes first and second warp beams feeding threads to said front needle row and third and fourth warp beams feeding threads to said rear needle row during the knitting of a given hosiery blank, and wherein said positive thread take-01f means includes separate change gear transmission means drivingly connected to said first and fourth warp beams for switching the rotative speeds of said Warp beams to increase the speed thereof durin the knitting of the reinforced areas of the hosiery blank, common infinitely variable transmission gear means drivingly connected to each of said separate change gear transmission means for gradually increasing the rotative speed of said first and fourth Warp beams as the Warp threads are fed therefrom and as the diameters decrease, and second infinitely variable transmission gear means drivingly connected to said second and third warp beams for gradually increasing the rotative speed of the same as the warp threads are fed therefrom and as the diameters decrease.

References Cited UNITED STATES PATENTS Bassist 6686 Lambach et a1. 66-86 Bassist 6686 Bassist 6686 Liebchen 6686UX Perrier 66195 10 RONALD FELDBAUM, Primary Examiner

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