GB1569644A - Method of compensating for charge loss during knitting of sliver high pile fabric - Google Patents

Description

(54) METHOD OF COMPENSATING FOR CHARGE LOSS DURING KNITTING OF SLIVER HIGH PILE FABRIC (71) We, HAYES-ALBION COR PORATION, a corporation organised and existing under the laws of the State of Delaware, United States of America, of 1300 Stanbridge Street, Norristown, Pennsylvania 19404, United States of America.

do hereby declare the invention. for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to a method of compensating for charge loss during knitting of sliver high pile fabric.

The sliver method of knitting high pile fabrics produces a charge loss known as ' fly loss". Such term. as used in the art, refers to all sliver fibres which are not incorporated into a sliver knit high pile fabric during knitting.

Fly loss occurs because the slivers or rovings used in knitting high pile fabrics are composed of relatively fine, short, discrete fibres, which are especially susceptible to diffusion during handling. In sliver knitting, an unavoidable relatively significant percentage of the fibres is lost as a sliver is transferred from its source of supply to the usual fibre carding and transfer mechanism, and thence to the needles of the knitting machine. The fly loss is relatively larger when a large number of needles are selected to rake sliver fibers from the doffer, whereas fly loss is relatively smaller when no needles, or only a small number of needles are selected to rake fibres from the doffer.

Wheelock U.S. Patent 2,993,351 and Thor U.S. Patent 3,728,872 illustrate apparatus designed for use with sliver knitters to recover fiber wasteage through fly loss.

The knitting of sliver high pile fabrics requires that a certain minimum quantity of fibers be in each sliver feeding system at all times, in order to produce fabrics of uniform pile density. This minimum quantity of fibres is defined as the "charge" of fibers in the feeding system necessary to meet the demand of the needles for fibers. The charge is composed of base fibers which tend to nestle within, and be retained by, the wire covering of the main cylinder and doffer of a sliver feed system, plus the fibers in transit to the needles, The transit fibres of the charge ride upon the base fibers, as they travel to the needles.

To produce pile fabrics of uniform pile density, the charge of fibres in a sliver feeding system must be maintained at a constant level. This presents no serious problem in the knitting of non-patterned work, since fly loss is relatively constant.

The rate of sliver input by sliver feed rolls is easily adjusted to feed sliver at a rate sufficient to produce fabric of selected pile denisty. while compensating for fly loss. In the knitting of non-patterned sliver high pile fabrics, it is possible to ignore fly loss altogether, and produce satisfactory fabric of uniform density. The finished fabric simply is of somewhat less pile density than would be the case if the fly loss either had been compensated for, or had not occurred.

However, in the knitting of multi-color patterned sliver high pile fabrics, which require selective feeding of various slivers either at variable rates or intermittently, a new problem arises. In knitting such fabrics, the sliver feed rolls cease feeding sliver altogether when needles are not selected.

Where only relatively few needles are selected, thereby diminishing the demand of the needles for fibers, the rate at which sliver is fed by the sliver feed rolls to the main cylinder and doffer may fall below the rate of fly loss. In such situations, the fly loss may create charge loss. i.e. may cause depletion of the fiber charge on the doffer and main cylinder in the sliver feeding system, thereby creating faults in the fabric being knitted. Charge loss results from fly loss and either the non-selection of needles or the minimal selection of needles. Charge loss may be defined as fly loss extending over a period of time when no additional fibers are added to the sliver feeding system, or insufficient fibers are added to compensate for fly loss.

In knitting multi-color sliver pile fabrics having intricate designs, it is essential, in order to obtain uniform pile density, to harmonize the rates at which selected slivers are fed by the doffer to selected needles with the demand of the needles for fibres. in accordance with the fabric pattern selected.

When, during the knitting of multi-color patterned fabrics, feeding of a sliver is stopped completely, or is reduced to a very low feeding rate, fly loss may cause partial or even complete depletion of the charge fibers from the sliver feeding system and particularly from the rapidly rotating doffer.

Where no sliver fibers are fed to a card for a sustained period, the doffer and even the main clyinder might empty completely of charge fibers through fly loss. If this occurs, the first needles eventually selected to receive fibers at such doffer may take no fibers at all, causing a fault in the fabric.

If. due to reduced needle selection. sliver fibers are fed at a minimal rate to the doffer.

the rate of feed may be less than the rate of fly loss. thereby reducing the fiber charge in the card. As a result. the few needles selected may draw an insufficient supply of fibers, causing a fault in the fabric.

Usually. fly loss presents no problems when a large number of needles are selected to rake sliver fibers from a doffer, because the level of the charge in the sliver feeding system remains constant. It is only when relatively few needles are selected, or none are selected, and the rate of sliver feeding varies accordingly, that the problem arises.

A primary object of this invention is to provide a new and improved method of knitting multi-colored patterned sliver high pile fabrics on circular knitting machines, which compensates for charge loss during knitting.

A further object of the invention is to provide a new and improved method for feeding sliver to a high pile fabric circular knitting machine in which the rate of sliver feed is proportional automaticallv to harmonize with the demand of selected needles for sliver fabrics, while compensating for charge loss resulting from fly loss and the nonselection or minimal selection of needles.

According to the present invention there is provided a method of compensating for charge loss in a sliver feeding system during knitting of mutli-colour patterned sliver high pile fabric on a multi-feed circular knitting machine, to provide patterned high pile fabric of substantially uniform pile density throughout the pattern, said sliver feeding system including a rotatable doffer for delivering fibers to the needles, a pair of selectively rotatable sliver feed rolls, characterised by continuously rotating the sliver feed rolls at selectively variable rates of speed to advance sliver fibers to the doffer at rates equal to any selected fabric patterning rate plus a selectively variable rate adjusted to approximate the rate of charge loss resulting from fly loss and the nonselection or the minimal selection of needles.

Further according to the present invention there is provided a method of compensating for charge loss in a sliver feeding system during knitting of multi-colour patterned sliver high pile fabric on a multi-feed circular knitting machine, to provide patterned high pile fabric in which the density of the pile is substantially uniform throughout the pattern, said machine having a plurality of sliver feeding cards spaced about the circle of needles. each card including a rotatable doffer for delivering sliver to the needles, a pair of selectively rotatable sliver feed rolls and a rotatable main cylinder interposed between the doffer and the feed rolls. and a needle selecting mechanism associated with each card and a varn feed disposed adjacent selected cards, the method comprising; feeding sliver fibers and yarns to the needles to knit multi-coloured patterned high pile fabric and sliver fibers being fed by each card to the needles at selected rates of feed; continuously selecting needles, according to predetermined needle selection pattern data, to receive sliver fibers from the doffers of selected cards and continuously rotating the sliver feed rolls at selected rates of speed to deliver sliver fibers to the main cylinder and doffer of each card at rates equal to any selected fabric patterning rate plus a rate calculated to compensate for the rate of charge loss resulting from fly loss and the non-selection or the minimal selection of needles.

Thus a minimum quantity of sliver fibers is maintained on each doffer during knitting. to ensure that sufficient quantities of pile fibers are available at all times to meet the demand of selected needles for fibers, to ensure the production of high quality fabric of uniform pile density.

Also, the rate of feed of each sliver to the needles is proportionate to the number of needles selected according to the design, the speed of rotation of the circle of needles, the selected pile density of the fabric and the rate of fly loss, but not less than a rate sufficient to compensate for any depletion of the charge fibers in the sliver feeding system.

Embodiments of the present invention will now be described by way of example with reference to the accompanying drawings in which: - Figure 1 is a schematic diagram illustrating an electronically controlled multi-feed sliver high pile fiber circular knitting machine incorporating a preferred embodiment of this invention; Figure 2 is a schematic block diagram illustrating functionally the data transfer electronic circuitry for controlling the rates of feed of the sliver feed rolls of each sliver feeding mechanism of the knitting machine: Figure 3 is a fragmentary, partially schematic view in perspective, showing one of the sliver feeding mechanisms or cards of the machine, utilizing a stepping motor to drive its sliver feed rolls; and Figure 4 is a fragmentary, schematic block diagram showing the data transfer electronic circuitry of Figure 2 incorporating supplemental control circuitry for the sliver feed rolls to operate the same continuously, at selected minimum rates of speed, to provide selected minimum rates of sliver feed to compensate for charge loss.

The improvements of the present inven tion may be incorporated into any known type of sliver high pile fabric circular knitting machine such as, for example. the sliver knitters illustrated in the following United States patents: Hill No. 3,010,297, Hill No.

3,014,355. Wiesinger No. 3,427,829, Schmidt No. 3.563,058, Brandt et al No.

3,709,002 and Christiansen et al No.

4,007,607. At the present time, the best mode contemplated for carrying out the invention is to incorporate it into the elec tronically controlled multi-feed sliver high pile fabric circular knitting machine dis closed in Christiansen et al U.S. patent 4,007,607. The disclosure of that patent is incorporated herein by reference.

Referring to the drawing. in Figure 1 there is shown schematicallv in top plan the knitting head of a multi-feed sliver high pile fabric circular machine M such as that illustrated in Christiansen et al U.S. patent 4,007,607 and having a plurality of indepen dent latch needles (not shown) mounted in a circle in a conventional needle cylinder (also not shown). with capacity for selected recip rocal movement. The cylinder is rotatable in the direction of the curved arrow.

In the embodiment shown. the machine M is provided with 12 sliver feeding stations, F1 to F12 inclusive, spaced at uniform intervals around the needle cylinder. Each such station includes a card C (Figure 3) having the usual wire-clothed rotatable dof fer 10 and main cvlinder 12. and a pair of rotatable sliver feed rolls 14. 16. The latter transfer a roving or sliver (not shown) from a source of supply via the main cylinder 12 to the doffer 10 for delivery to selected needles. The feed rolls are driven by a stepping motor 20 through a conventional timing belt drive 22 and conventional gearing 24.Disposed at each sliver feeding station F1-F12, in advance of its card C, are needles selecting mechanisms S1 to S12, respectively, each of which is composed of a plurality of individual electromagnetic needles selecting acutators of the type illustrated in Christiansen U.S. patent 3,896,639.

The electronic control apparatus for selecting needles includes a main memory 30. a buffer memory 32 and needle control logic circuitry 34, the latter being connected electrically by conventional circuitry to each separate electromagnetic acutator of the needle selecting mechanisms S1 to S12 inclusive. A power amplifier 36 is interposed in the circuit connecting each needle selecting actuator to the needle control logic circuitry 34. In the interest of brevity, only one circuit is shown in Figure 1 connecting the needle control logic 34 to an electromagnetic needle selecting actuator (at S1).

Data is transferred from the main memory 30 to the electromagnetic actuators in response to signals generated by an absolute encoder 38 geared to the knitting machine M. Encoder 38 generates a train of pulses, proportional to the speed of rotation of the needle cylinder, to enable sequentially the several actuators of the successive needle selecting mechanisms S1-S12.

The electronic control apparatus for the knitting machine M also includes control circuitry for regulating continuously the speed of rotation of the stepping motors 20 associated with each of the 12 cards C, to control selectively the rate of sliver feed at each station F1-F12. The electronic control for the stepping motors includes card feed rate logic circuitry 40, connected electrically to each stepping motor 20 by separate circuitry which includes decoding logic circuitry 42 and a power amplifier 44. The decoding logic 42 decodes the pulse train from the card feed rate logic circuitry 40 to the input form required by the stepping motors 20.

For the purpose of illustration, only one circuit is shown in Figure 1 connecting the card feed rate logic 40 to one of the stepping motors 20 at a sliver feeding station (F1). It is to be understood that a separate circuit, each provided with its own decoding logic 42 and power amplifier 44, connects each stepping motor 20 of each card C to the card feed rate logic circuitry. To ensure that the sliver feeding rates of the 12 cards C are at all times proportional to the speed of rotation of the needle cylinder, the card feed rate logic circuitry 40 is clocked by a signal directly proportional to the rotative speed of the needle cylinder. The pulse output of the absolute encoder 38 may be utilized to provide the needle clock input to the card feed rate logic.

The card feed rate logic circuitry 40 is illustrated schematically in Figure 2 by the portion of the functional block diagram interposed between the buffer memory 32 and the stepping motor decoding logic 42.

As explained in Christiansen et al U.S.

patent 4,007,607 aforesaid, the logic depicted in Figure 2 renders unnecessary incorporating into the main memory 30 sliver feed control data, for controlling the rates at which sliver is fed at each sliver feeding station F1-F12. The electronic control system depicted in Figure 2 calculates continuously and accurately the necessary sliver feeding rates using the needle selection pattern data stored by the memory 30.

The calculations are carried out by a data calculating and transfer circuit, which includes the buffer memory 32 for the temporary storage of needle selection pattern data, counter 50, multiplier 52, divider 54. rate multiplier 56 and buffer shift register 60.

In addition to using needle selection pattern data retrieved from the memory 30, the data calculating and transfer electronic circuit incorporates into its calculations, from the input of clock pulses at the "ma" number, the selected speed of rotation of the needle cylinder. It also incorporates into its calculations the selected pile density of the fabric being knit, from a set of thumbwheel switches (not shown). the selected setting of which is applied to rate multiplier 58 interposed between rate multiplier 56 and buffer shift register 60.

The sliver feeding rate data obtained from the second rate multiplier 58 is stored in the buffer shift register 60. to which also are applied the "ma" clock pulses previously referred to. The data stored in the buffer shift register 60. at the appropriate time, is transferred to one of the active shift registers R1-R12 connected by suitable circuitry to one of the stepping motors for one of the twelve cards.

Figure 2 illustrates an arrangement by which rate data is transferred from the buffer shift register 60 to the active shift registers R1. which controls the stepping motor 20 of the card C at sliver feeding station F1. The active shift register R1 is clocked by the pulse output of the encoder 38. which is proportional to the speed of rotation of the needle cylinder. The data output of the active shift register R1 is combined with this clock, as indicated by the "and" function block 62.The resulting pulse train is decoded bv the stepping motor decoding logic 42 and amplified by the power amplifier 44. to drive the stepping motor 20 at the speed necessary for card C to feed sliver at a selected rate in harmonv with the fabric pattern selected. The result is to provide a card with continuously controlled sliver feed roll drive means, calculated to ensure that the sliver input to the machine harmonizes with the demand of selected needles for fibers, the speed of rotation of the circle of needles and the desired pile density of the fabric.

As explained previously, charge loss may arise and create faults in multi-color patterned sliver knit fabrics where the feed of a sliver temporarily is stopped completely, due to non-selection of needles or is reduced to a very low rate because relatively few needles are selected to receive fibers. To compensate for this, and maintain constant the fiber charge in a sliver feeding system.

the present invention provides for the continuous rotation of the sliver feed rolls 14.

16, at selectively adjustable minimum rates of rotation, calculated to feed sliver at minimum rates approximating the rate of fly loss. preferably at a rate equal to or slightly greater than the rate of fly loss during the non-selection or minimal selection of needles. Arranging for the sliver feed rolls 14, 16 to rotate continuously at selected minimum speeds of rotation to compensate for charge loss, ensures that a sufficient quantity or charge of fibers is maintained on the doffer 10 at all times during knitting to meet the demand of selected needles for fibers, and to avoid faults in the pile density of the fabric.

The additional logic or control circuitry required to obtain such selected minimum rates of sliver feed is illustrated in Figure 4.

It comprises a divider 70, rate multiplier 72.

anti-coincidence circuit 74 and "or" gate 76.

The control logic to obtain the desired selected minimum rates of sliver feed is interposed in the basic data calculating and transfer electronic circuit between rate multiplier 58 and buffer shift register 60.

By way of illustration, it will be assumed that not more than 93 of each 100 data bits (i.e. discrete commands for needles to take sliver or to welt) transferred from rate multiplier 58 and stored in the buffer shift register 60, will be binary or logic "1's" (i.e.

needle commands to take sliver). The sliver therefore is advanced at its selected maximum feeding rate by the feed rolls 14, 16 when 93 of each 100 data bits entered on the shift register 60 are logic "1's". This arrangement provides for the possibility of increasing the speed of the stepping motor 20 by 7/93, or approximately 7.5% beyond the selected maximum speed, resulting in a corresponding increase in the sliver feed rate.

The train of clock pulses "ma" applied to the buffer shift register 60 supplies one pulse for each data bit, i.e. for each logic "1" or '0", entered in the register. As explained in Christiansen et al U.S. patent 4,007,607 aforesaid, in the clock "ma" the designation "m" is a selected constant comprising a scaling factor and the designation "a" denotes the data bits or commands for a selected number of needles "a". In the example given, "a" = 100 data bits. Since the number of pulses of the buffer shift register clock "ma" is proportional to the maximum sliver feed rate (i.e. 93 logic "1's" randomly evenly distributed for each 100 data bits), a pulse train which represents any fraction of the maximum sliver feed rate may be obtained by dividing the "ma" clock pulses by any appropriate number "n".The divisor "n" is a number which, when divided into "ma", produces a quotient preferably and normally, but not necessarily, equal to or less than the difference between the data bits, "a" of the clock "ma" and the maximim logic "1's" per "a" data bits (in the example given. the difference is 100 - 93 7).

In the modified electronic circuit of Figure 4. the divider 70 and the rate multiplier 72 are utilized to divide by "n" the buffer shift register clock "ma". to provide the minimum sliver feed rate data. The divided clock is entered into the buffer shift register 60 as additonal data bv adding it via "or" gate 76 to the sliver feed rate data obtained from the data calculating and transfer circuit interposed between main memory 30 and buffer shift register 60. The minimum sliver feed rate data. obtained from the divided buffer shift register clock, must be added to the register 60 when the data entered from the rate multiplier 58 is a logic "0".The anit-coincidence circuit 74. connected to the rate multiplier 58 and the "or" gate 76 ensures this, bv detecting the presence of a logic "0" data bit entering the buffer shift register 60 from the rate multiplier 58.

The invention thus permits continuous feeding of sliver by the sliver feed rolls 14, 16 to the main cylinder 12 and doffer 10. at selectively variable rates of sliver feed. such rates being proportionate to the number of needles selected, the speed of rotation of the circle of needles. the selected pile density of the fabric and the rate of fly loss, to maintain the charge of fibers in the sliver feeding system at a constant level at all times.

In practice a minimum rate of sliver feed of 1% of the maximum rate of sliver feed may be sufficient to compensate for any depletion of the charge. However, since fly loss will occur at various rates. under various knitting conditions. it is desirable to provide means to adjust easilv and selectively the compensating minimum rate of sliver feed. For this purpose, a high-low divisor switch (not shown) providing for two basic speed ranges. m or 2m. furnishes a selected input to the divider 70. Additionally, a second thumbwheel switch (not shown), graduated from 0 through 9, with input to the rate multiplier 72, is provided for adjusting further the minimum sliver feeding rates through either of the two speed range settings provided by the divisor switch aforesaid.

The arrangement illustrated in Figure 4 ensures that, at all times during knitting, when needles are selected to rake fibers from the doffer, the sliver is fed at a rate adequate to provide sufficient quantities of fibers on the doffer to meet the fiber demand of selected needles, as required by the fabric pattern, and to compensate for charge loss resulting from fly loss and the non-selection or minimal selection of needles. Thus, there is provided a new and improved method of sliver knitting, whereby the rate of sliver delivery to the doffer at all times is carefully controlled, so that it is proportionate to the number of needles selected according to the design, the rotation of the needles, the pile density of the fabric and the rate of fly loss, to maintain the charge of fibers in a sliver feeding system at a constant level at all times.The method of the invention ensures operating the sliver feed rolls at selected minimum speeds necessary to advance sliver to the doffer at rates sufficient to compensate for any depletion of the charge.

In the claims which follow, the terms (1) "selected fabric patterning rate".shall indicate a rate of demand of selected needles for fibers. according to a selected fabric pattern, and (2) "mininal selection of needles" shall indicate the selection of so few needles that the demand of the needles for fibers, according to a selected fabric pattern, is less than the rate of fly loss from the sliver feeding system.

WHAT WE CLAIM IS: 1. A method of compensating for charge loss in a sliver feeding system during knitting of multi-color patterned sliver high pile fabric on a multi-feed circular knitting machine, to provide patterned high pile fabric of substantially uniform pile denisty throughout the pattern. said sliver feeding system including a rotatable doffer for delivering fibers to the needles, and a pair of selectively rotatable sliver feed rolls, characterized by continuously rotating the sliver feed rolls at selectively variable rates of speed to advance sliver fibers to the doffer at rates equal to any selected fabric patterning rate plus a selectively variable rate adjusted to approximate the rate of charge loss resulting from fly loss and the nonselection or the minimal selection of needles.

2. The method of Claim 1, characterized by rotating the sliver feed rolls at selectively

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (11)

**WARNING** start of CLMS field may overlap end of DESC **. aforesaid, in the clock "ma" the designation "m" is a selected constant comprising a scaling factor and the designation "a" denotes the data bits or commands for a selected number of needles "a". In the example given, "a" = 100 data bits. Since the number of pulses of the buffer shift register clock "ma" is proportional to the maximum sliver feed rate (i.e. 93 logic "1's" randomly evenly distributed for each 100 data bits), a pulse train which represents any fraction of the maximum sliver feed rate may be obtained by dividing the "ma" clock pulses by any appropriate number "n".The divisor "n" is a number which, when divided into "ma", produces a quotient preferably and normally, but not necessarily, equal to or less than the difference between the data bits, "a" of the clock "ma" and the maximim logic "1's" per "a" data bits (in the example given. the difference is 100 - 93 7). In the modified electronic circuit of Figure 4. the divider 70 and the rate multiplier 72 are utilized to divide by "n" the buffer shift register clock "ma". to provide the minimum sliver feed rate data. The divided clock is entered into the buffer shift register 60 as additonal data bv adding it via "or" gate 76 to the sliver feed rate data obtained from the data calculating and transfer circuit interposed between main memory 30 and buffer shift register 60. The minimum sliver feed rate data. obtained from the divided buffer shift register clock, must be added to the register 60 when the data entered from the rate multiplier 58 is a logic "0".The anit-coincidence circuit 74. connected to the rate multiplier 58 and the "or" gate 76 ensures this, bv detecting the presence of a logic "0" data bit entering the buffer shift register 60 from the rate multiplier 58. The invention thus permits continuous feeding of sliver by the sliver feed rolls 14, 16 to the main cylinder 12 and doffer 10. at selectively variable rates of sliver feed. such rates being proportionate to the number of needles selected, the speed of rotation of the circle of needles. the selected pile density of the fabric and the rate of fly loss, to maintain the charge of fibers in the sliver feeding system at a constant level at all times. In practice a minimum rate of sliver feed of 1% of the maximum rate of sliver feed may be sufficient to compensate for any depletion of the charge. However, since fly loss will occur at various rates. under various knitting conditions. it is desirable to provide means to adjust easilv and selectively the compensating minimum rate of sliver feed. For this purpose, a high-low divisor switch (not shown) providing for two basic speed ranges. m or 2m. furnishes a selected input to the divider 70. Additionally, a second thumbwheel switch (not shown), graduated from 0 through 9, with input to the rate multiplier 72, is provided for adjusting further the minimum sliver feeding rates through either of the two speed range settings provided by the divisor switch aforesaid. The arrangement illustrated in Figure 4 ensures that, at all times during knitting, when needles are selected to rake fibers from the doffer, the sliver is fed at a rate adequate to provide sufficient quantities of fibers on the doffer to meet the fiber demand of selected needles, as required by the fabric pattern, and to compensate for charge loss resulting from fly loss and the non-selection or minimal selection of needles. Thus, there is provided a new and improved method of sliver knitting, whereby the rate of sliver delivery to the doffer at all times is carefully controlled, so that it is proportionate to the number of needles selected according to the design, the rotation of the needles, the pile density of the fabric and the rate of fly loss, to maintain the charge of fibers in a sliver feeding system at a constant level at all times.The method of the invention ensures operating the sliver feed rolls at selected minimum speeds necessary to advance sliver to the doffer at rates sufficient to compensate for any depletion of the charge. In the claims which follow, the terms (1) "selected fabric patterning rate".shall indicate a rate of demand of selected needles for fibers. according to a selected fabric pattern, and (2) "mininal selection of needles" shall indicate the selection of so few needles that the demand of the needles for fibers, according to a selected fabric pattern, is less than the rate of fly loss from the sliver feeding system. WHAT WE CLAIM IS:

1. A method of compensating for charge loss in a sliver feeding system during knitting of multi-color patterned sliver high pile fabric on a multi-feed circular knitting machine, to provide patterned high pile fabric of substantially uniform pile denisty throughout the pattern. said sliver feeding system including a rotatable doffer for delivering fibers to the needles, and a pair of selectively rotatable sliver feed rolls, characterized by continuously rotating the sliver feed rolls at selectively variable rates of speed to advance sliver fibers to the doffer at rates equal to any selected fabric patterning rate plus a selectively variable rate adjusted to approximate the rate of charge loss resulting from fly loss and the nonselection or the minimal selection of needles.

2. The method of Claim 1, characterized by rotating the sliver feed rolls at selectively

variable rates of speed to advance sliver fibers to the main cylinder and doffer at rates sufficient to compensate for any depletion of the fiber charge.

3. A method according to either of Claims 1 or 2, characterized by rotating the sliver feed rolls, at selectively variable rates of speed to maintain a sufficient quantity of fibers on the doffer at all times to meet the demand of selected needles for fibers according to a selected pattern.

4. A method according to any of the preceding claims, characterized by continuously rotating the sliver feed rolls to advance sliver fibers to the doffer at selected rates not less than a rate substantially equal to the rate of charge loss.

5. A method of compensating for charge loss in a sliver feeding system during knitting of multi-color patterned sliver high pile fabric on a multi-feed circular knitting machine, to provide patterned high pile fabric in which the density of the pile is substantially uniform throughout the pattern, said machine having a plurality of sliver feeding cards spaced about the circle of needles, each card including a rotatable doffer for delivering sliver to the needles, a pair of selectively rotatable sliver feed rolls and a rotatable main cylinder interposed between the doffer and the feed rolls, and a needle selecting mechanism associated with each card and a yarn feed disposed adjacent selected cards, the method comprising (a) feeding sliver fibers and yarns to the needles to knit multi-colored patterned high pile fabric, said sliver fibers being fed by each card to the needles at selected rates of feed.

(b) continuously selecting needles, according to predetermined needle selection pattern data, to receive sliver fibers from the doffers of selected cards and (c) continuously rotating the sliver feed rolls at selected rates of speed to deliver sliver fibers to the main cylinder and doffer of each card at rates equal to any selected fabric patterning rate plus a rate calculated to compensate for the rate of charge loss resulting from fly loss and the non-selection or the minimal selection of needles.

6. The method of Claim 5 wherein the sliver feed rolls are driven rotatably by a variable speed motor, comprising continuously operating the motor to cause the sliver feed rolls to rotate at variable speeds of rotation, to deliver sliver fibers to the doffer at selected rates of feed to maintain a sufficient quantity of fibers on the doffer at all times to meet the demand of selected needles for fibers according to a selected pattern.

7. The method of Claim 5. wherein the rate of sliver delivery to the main cylinder and doffer of each card is continuously controlled, whereby the rate of sliver delivery is proportionate to (a) the demand of selected needles for sliver fibers in accordance with a predetermined needle selection pattern, (b) the speed of rotation of the circle of needles, (c) the selected density of the pile of the fabric being knit and (d) the rate of fly loss, but not less than a rate sufficient to compensate for any depletion of the fiber charge in the sliver feeding system.

8. The method of Claim 5, wherein each pair of sliver feed rolls is driven rotatably by a variable speed motor, comprising continuously operating and controlling the motor to cause the sliver feed rolls to rotate at selected speeds of rotation, to deliver sliver fibers to the doffer at a rate of delivery proportionate to (a) the number of needles selected to receive sliver fibers from the doffer, (b) the speed of rotation of the circle of needles, (c) the desired pile density of the fabric, and (d) the rate of fly loss. but not less than a rate sufficient to compensate for any depletion of the fiber charge in the sliver feeding system.

9. A method of compensating for charge loss in a sliver feeding system during knitting of multi-colour patterned sliver high pile fabric on a multi-feed circular knitting machine substantially as hereinbefore described with reference to the accompanying drawings.

10. Apparatus for carrying out the method claimed in any one of claims 1 to 10 substantially as hereinbefore described with reference to the accompanying drawings.

11. A mutli-feed circular knitting machine including means for compensating for charge loss in a sliver feeding system during knitting of multi-colour patterned sliver high pile fabric, substantially as hereinbefore described with reference to the accompanying drawings.