US3886767A

US3886767A - Method of modifying a pile fabric machine

Info

Publication number: US3886767A
Application number: US399144A
Authority: US
Inventors: Philip A Dargie
Original assignee: Malden Mills Industries Inc
Current assignee: Malden Mills Industries Inc
Priority date: 1973-09-20
Filing date: 1973-09-20
Publication date: 1975-06-03
Anticipated expiration: 1992-06-03

Abstract

There is disclosed a method of modifying a pile-fabric knitting machine so that it is capable of producing fabrics at a much faster rate. In a conventional prior art machine, yarn-feed and fiber-feed stations alternate with each other around the needle cylinder; each needle picks up fiber and then forms a stitch. In accordance with the invention, yarn-feed stations are added so that two yarn-feed stations separate successive fiber-feed stations. This results in the knitting of alternate courses of plain stitches and fiber stitches. Because there are twice as many yarn-feed stations, fabric can be produced at twice the rate. By doubling the fiber feed rate so that each fiber stitch contains twice the amount of fiber in a stitch of a fabric made on a comparable prior art machine, there is no loss in fabric quality.

Description

United States Patent [191 Dargie June 3, 1975 METHOD OF MODIFYING A PILE FABRIC MACHINE [75] Inventor: Philip A. Dargie, Andover, Mass.

[73] Assignee: Malden Mills, Inc., Lawrence, Mass.

[22] Filed: Sept. 20, 1973 211 Appl. No.: 399,144

[52] US. Cl. 66/9 B; 66/194 [51] Int. Cl. D04b 9/14; D04b 9/12 [58] Field of Search 66/9 B, 10, ll, 12, 190, 66/194,191, 9 R, 42 R [56] References Cited UNITED STATES PATENTS 229,896 7/1880 Love 66/194 1,894,596 1/1933 Moore. 66/9 B 2,146,647 2/1939 Page 66/42 2,255,078 9/1941 Moorew. 66/9 B 3,023,596 3/1962 Hill 66/9 B 3,328,979 7/1967 Frishman 66/9 B 3,413,823 12/1968 Beucus et a1. 66/194 F I BE R FE ED 0 Primary Examiner-W. C. Reynolds Assistant Examiner-A. M. Falik Attorney, Agent, or FirmGottlieb, Rackman, Reisman & Kirsch [57] ABSTRACT There is disclosed a method of modifying a pile-fabric knitting machine so that it is capable of producing fabrics at a much faster rate. In a conventional prior art machine, yarn-feed and fiber-feed stations alternate with each other around the needle cylinder; each needle picks up fiber and then forms a stitch. In accordance with the invention, yarn-feed stations are added so that two yarn-feed stations separate successive fiber-feed stations. This results in the knitting of alternate courses of plain stitches and fiber stitches. Because there are twice as many yarn-feed stations, fabric can be produced at twice the rate. By doubling the fiber feed rate so that each fiber stitch contains twice the amount of fiber in a stitch of a fabric made on a comparable prior art machine, there is no loss in fabric quality.

2 Claims, 10 Drawing Figures Y1 Fl) FIBER FEED 17' PM'EWEDJJIH m5 SHEET COURSE Y4=WWWWWWWWWWWW YFWWWWWWWWWWWW YUWWWWWWWWWWWW YUWWWWWWWWWWWW FIG. 3

METHOD OF MODIFYING A PILE FABRIC MACHINE This invention relates to pile-fabric knitting machines. and more particularly to prior art type machines which, with relatively simple modifications. can produce the same quality but at a much increased rate.

A conventional pile-fabric knitting machine is provided with alternating fiber-fced and yarn-feed stations around a needle cylinder. As each needle rotates with the cylinder, it is first raised to pick up fiber at a fiberfeed station, and it then engages yarn at the immediately following yarn-feed station. After the yarn is engaged, the needle is lowered and a stitch is formed. The needle is raised once again as it approaches the next fiber-feed station. A machine of this type produces a knitted fabric in which every stitch contains fiber. The number of courses, that is, the length of the fabric, which is knitted during each cylinder revolution is directly proportional to the number of yarn feeds.

Because each fiber-feed station occupies so much space on top of and along the circumference of the cylinder, a pile-fabric knitting machine can be equipped with only a fraction of the number of yarn feeds that is usually found on an ordinary knitting machine. Accordingly, the rate of fabric production is very low.

It is a general object of my invention to increase the rate of production of pile fabrics using prior art type knitting machines.

Although the basic concept of my invention has application to machines of different manufacture, and to machines which produce many different types of pile fabrics, the principles of the invention can be best understood by considering a machine for producing a jersey knit in which pile fabric is included in each stitch, a machine such as that described above. In one illustrative embodiment of the invention, I add a yarn-feed station following each yarn-feed station on the original machine. Thus, there are two yarn feeds between successive fiber feeds. As each needle picks up fiber at a fiber-feed station and then engages a yarn, it forms a fiber-containing stitch in one course. The needle is then raised, engages the next yarn, and is then lowered to form a stitch in the next course. The process then repeats itself. The resulting fabric has alternating courses of two types. The courses of the first type are the same as those in prior art fabrics; each stitch contains fiber. The courses of the second type contain plain stitches, with no fiber. Because the modified machine hastwice as many yarn feeds, fabric can be produced at twice the rate.

I have found that this can be done with many different type fabrics with no loss in quality, and especially with shearling, shag and trim fabrics. All that is required is to double the rate of each fiber feed so that twice as much fiber is contained in each of the fiber courses, that is, the weight of the fiber per unit area in the fabric or my invention is the same as the weight of the fiber in a comparable prior art fabric having the same appearance.

It is a feature of my invention to provide a pile-fabric knitting machine which has at least two yarn feeds with no fiber-feeding device between them.

It is another feature of my invention to modify an existing pile-fabric knitting machine by adding to it at least one yarn feed which immediately follows an already existing yarn feed in the direction of the needle movement.

It is another feature of my invention to provide a knitted pile fabric which contains some plain courses with no fiber in the stitches thereof.

It is another feature of my invention to provide such a fabric with fiber courses which contain a greater amount of fiber in each stitch than comparable fabrics which have no plain courses, so that the two fabrics have substantially the same appearance and weight of fiber per unit area.

Further objects, features and advantages of my invention will become apparent upon consideration of the following detailed description in conjunction with the drawing, in which:

FIG. 1 depicts a conventional weft fabric made on a circular knitting machine;

FIGS. 28 depict symbolically the following machines and the fabrics which they produce:

FIG. 2 a prior art machine for producing a jersey knitted pile fabric in which every stitch has the same type of fiber,

FIG. 3 the machine of FIG. 2 as modified in accordance with the principles of my invention,

FIG. 4 a prior art machine having a needleselecting capability for producing fabrics with walewise patterns,

FIG. 5 a prior art machine which is a modification of the machine of FIG. 4 for producing fabrics having walewise patterns at a faster rate,

FIG. 6 the machine of FIG. 5, as modified in accordance with the principles of my invention for producing fabrics at an even faster rate,

FIG. 7 another type of prior art machine for producing fabrics having walewise patterns at a rate comparable to the rate at which fabrics are produced by the prior art machine of FIG. 5, and

FIG. 8 the machine of FIG. 7, as modified in accordance with the principles of my invention;

FIG. 9 depicts symbolically the arrangement in a prior art machine of those parts necessary for an understanding of the present invention, and

FIG. 10 depicts symbolically the changes required in the machine depicted in FIG. 9 to achieve the faster fabric production rate contemplated by my invention.

High-pile fabrics are generally manufactured on circular knitting machines equipped with fiber-feeding devices which take fibers from silver or other loosely bound fiber assemblies and transfer the fibers to the hooks of the knitting needles. As the knitting needles are manipulated to form yarn into interlocking loops, the fibers supplied by the fiber-feeding devices are bound in with the yarn loops to form a pile surface on the face of the knitted fabric. As with conventional fabrics made on circular knitting machines, after the initial knitting operation a high-pile fabric is slit longitudinally and subjected to a variety of finishing treatments.

Typically, the weft knitting machine used to manufacture high-pile fabric is provided with a revolving open-top cylinder which carries latch needles. Around the top of the cylinder there are provided silver-feed stations, which basically are the type of carding units employed in yarn manufacture. A plain jersey fabric is formed by conventional needle and sinker action from yarns fed from a yarn creel. When a needle is raised. the carding unit doffer allows the needle hook to seize strands of fiber just prior to the feed of yarn to the needle. The resulting stitch which is then formed in a conventional jersey stitch but with fiber locked into place on the fabric.

The speed at which fabric can be manufactured on a revolving cylinder knitting machine depends upon the number of yarn feeds disposed around the cylinder. The number of needles carried by the cylinder determines the number of stitches formed in each course (that is, the number of stitches around the circumference of the circular knitted fabric). But the length of the circular knit fabric which is made during each revolution of the revolving cylinder is a function of the number of courses which are formed, and this, in turn. is a function of the number of yarn feeds. A conventional 23-inch diameter knitting machine, for example, is typically equipped with up to 64 yarn feeds. But not nearly as many yarn feeds can be employed on the same machine when making a pile fabric. This is because each fiber-feed station takes up a considerable amount of space on top of the cylinder an are along the circumferential edge of the cylinder which could otherwise have supported above it several yarn feeds (with the necessary needle cams for each yarn feed). In a conventional present-day pile-fabric knitting machine, no more than a dozen yarn feeds are provided, each yarn feed having a carding unit for furnishing fiber to each needle as it revolves with the cylinder just before it reaches the yarn feed. Thus no more than a dozen courses in the circular knitted fabric can be made during each cylinder revolution.

There are many variations of the basic pile-fabric knitting machine just described. For example, in a machine equipped for needle selection, not every needle picks up fiber from every doffer. Similarly, it is often possible to automatically change the type of fiber (silver) fed to each doffer as the cylinder revolves. The effects of needle and silver selection will be described below. But all machines of the general type described can knit at increased capacity if they are modified by the addition of yarn feeds in accordance with the principles of my invention. Several different types of prior art machines and the types of fabrics that they can produce will now be described, together with the fabrics which they can produce when they are modified in accordance with the principles of my invention.

FIG. 1 depicts a conventional weft fabric made on a circular knitting machine. It is to be understood that the fabric has a cylindrical configuration, with each course being along a circle defined by the intersection of a horizontal plane with the vertical cylindrical fabric. Looking in the vertical direction, each set of stitches is referred to as a Wale. It will be noted that each course is made of a single yarn; a complete course is made by every needle on the revolving cylinder forming a stitch. Thus the diameter of the circular knitted fabric is a function of the number of needles. The number of courses made during each revolution of the cylinder is equal to the number of yarn feeds; the length of fabric produced per unit time on a machine whose cylinder speed is constant is directly proportional to the number of yarn feeds.

Although the fabric depicted in FIG. 1 is a conventional jersey fabric, it is to be understood that the drawing also depicts a pile fabric. A pile fabric simply has fiber strands intersected in each stitch.

FIG. 2 depicts the arrangement of yarn and fiber feed stations on top of a revolving cylinder in a machine which produces a jersey knit pile fabric. There are four fiber-feed stations, numbered 1-4, and four yarn-feed stations numbered Y1-Y4. The letter W adjacent to each fiber-feed station is intended to indicate that each station feeds white fiber to each needle which moves past it. The cylinder revolves in the counter-clockwise direction as indicated, and every needle picks up fiber and then yarn as it passes each of the four fiber-yarn stations around the periphery of the needle cylinder. As is known in the art. as each needle approaches a fiberfeed station a cam causes it to rise so that it passes by the doffer during which time fibers are furnished to the hook of the needle. As the needle moves on, it engages the respective yarn. after which a cam surface causes the needle to move downward and a stitch to be formed. (The terms fiber-feed station and yarn-feed station include the mechanisms known in the art for controlling needle movement at the stations.)

The four rows of symbols on the right side of FIG. 2 are intended to depict the type of pile fabric made by the respective machine. During each revolution of the cylinder, the first course is made with yarn fed at station Y]. The second course is made with yarn fed at station'Y2, etc. Since the knitted fabric moves downward, the first course is represented in row Yl,and the last course is represented in row Y4. In the hypothetical example under consideration, it is assumed that there are 12 needles in the cylinder. (In an actual knitting machine, there are many. many more.) Since white fiber is supplied to every needle at each fiber-feed station, every stitch along each course contains such fiber, and is represented by a W in FIG. 2. During a single revolution of the cylinder, four courses are formed, and each course has 12 stitches each of which contains white fiber.

The machine configuration of FIG. 2 is very common; many pile fabrics are of a single color. In accordance with the principles of my invention, the machine of FIG. 2 can be modified so that it produces a fabric of the same quality and appearance, but at twice the rate (even though the speed of the cylinder remains constant). Of the upmost significance of the following:

I. The doubled capacity can be achieved at minimal additional cost and by using standard parts, and

2. the numerous existing machines already in use can be modified to double their capacity. that is, the invention is not limited to new" machines.

FIG. 3 depicts the modified machine. It is the same as the original machine, except that four additional yarn-feed stations Yl'-Y4' are provided around the periphery of the cylinder. Each additional yarn-feed station is the same as an old one; in addition to the yarn feed itself, cams are provided for raising each needle as it approaches the yarn and then lowering it after the yarn has been engaged so that a stitch can be formed. A yarn-feed station requires so little space along the periphery of the cylinder that even eight-fed (fiber eightfeed yarn) machines have been modified by adding to them eight additional yarn feeds.

As shown to the right of the drawing of FIG. 3, the course formed from the yarn at station Yl contains twelve stitches. each having white fiber in it. This is because the fiber feed and the yarn feed at the first combined station cooperate with each of the 12 needles just as the same combined station in the machine of FIG. 2 cooperates with each of the needles. But after each needle forms a stitch in course Yl, it is then raised as it approaches yarn-feed stations Yl'. It then engages the additional yarn and forms a stitch as it is lowered. Thus the twelve needles form an extra course represented by row Yl in FIG. 3. Since no fiber is fed into each needle hook before it reaches station Y1, course Yl' is shown in FIG. 3 by 12 dashes. Thus in the first quadrant of the machine, two courses are formed, one with pile fibers and the other without. Similar remarks apply to the other four quadrants. It is thus apparent that the number of courses formed during each cylinder revolution is eight, rather than four, and the length of the fabric in the wale direction which is formed during each unit of time is exactly twice that formed with the machine of FIG. 2. The capacity of the machine can thus be doubled simply by adding an additional yarn feed following each fiber-yarn station on the original machine.

The full advantages of my invention usually cannot be achieved unless the quality of the fabric produced with the machine of FIG. 3 is the same as the quality of the fabric produced with the machine of FIG. 2. I have found that with many fabrics, especially those with a long pile or a high fiber density, the same quality fabric can be produced simply by doubling the fiber feed to each needle at each of the fiber-feed stations. (Each fiber-feed station includes a fiber-feed rate control mechanism.) When this is done, even experts cannot tell the difference between fabrics produced on the two machines when examining the fabric faces. Because the amount of fiber fed to each needle is doubled, there is not net serving in fiber cost; eight courses of fabric made with the machine of FIG. 3 have the same amount of fiber as eight courses of fabric made with the machine of FIG. 3. (Of course, variations are contemplated; the fiber-feed rate need not be exactly doubled.) The difference between the two machines 2. that it takes only one revolution of the cylinder in the machine of FIG. 3 to make the eight courses, while it takes two revolutions of the cylinder of the machine of FIG. 2 to make the same number of courses.

It might be thought that for fabrics made with the machines of FIGS. 2 and 3 to have the same appearance, the stitches in the plain courses of the latter fabric should be smaller. This could be accomplished by decreasing the rate at which yarn is fed at yarn-feed stations Y1 'Y4' as compared to the rate at which yarn is fed at yarn-feed stations Yl-Y4. A typical pile-fabric knitting machine is equipped with a tape which drives the yarn-feed mechanisms. Where two different yarnfeed rates are equipped in a machine, tandem tapes are generally used. It was originally thought that tandem tapes would be required, and that the plain-stitch courses should have smaller stitches. (This would allow a less than doubled capacity to be achieved.) However, it has thus far been found that fabric made on a ma- Chine having a single tape drive, that is, in which the size of the plain stitches is the same as the size of the pile stitches, is of the highest quality. Thus, it is not necessary to equip a machine with an additional tape drive mechanism; the same tape drive used to control the feed of yarns Yl- Y4 can be used to control the feed of yarns Yl'-Y4'.

Of course, it is to be understood that different effects can be achieved by varying the stitch sizes (for example, with the use of tandem tapes). as well as the amount of fiber fed to the needles. But the advantages of the invention can be appreciated by noting that the machine rate of fabric production can be doubled without any sacrifice in fabric quality, and at a cost which is only a fraction of the cost of the original machine. The crux of the invention is that additional yarn feeds are provided between regular pairs of fiber and yarn feeds, so that a fabric can be knit with additional plain yarn courses all around the circumference of the fabric. A circular knitting machine so equipped has at least two yarn feeds with no fiber-feeding device between them. (Of course, if one of the additional yarn feeds' YI'Y4 is omitted, then the capacity of the machine would be increased by only percent: but unless the various pairs of fiber and yarn stations are not equally spaced, there would be no advantage in omitting any of the additional yarn feeds which can be squeezed in.) It should further be noted that it is possible to provide two additional yarn feeds between each pair of fiberyarn stations. But this would result in a fabric having two plain courses between successive fiber courses, and it has been found that the quality of such a fabric is not as good as the quality of the fabric produced on the original machine.

It is to be expected that some prior art machines actually did knit fabrics with courses having plain, nonfiber stitches but by accident. In a typical plant, workers constantly supervise the sliver supplies for the various fiber-feed stations; when the sliver supply at any station is low, more sliver is added. But suppose that a sliver supply is accidentally allowed to run out While the machine continues to run, for example, the sliver supply at fiber-feed station 2 in FIG. 2; in such a case, although all needles should pick up fiber prior to reaching yarn-feed station Y2, they do not. The resulting fabric has plain, non-fiber stitches in course Y2. It it is to be expected that such accidents have happened in the past.

But the accidental fabrics thus produced must have been of inferior quality (and were sold as such, if at all) because they were necessarily non-uniform. Even if stations Y2 and Y4 run out of fiber, while the resulting fabric will be uniform, it will not have its intended appearance; it will be of inferior quality. To distinguish the fabric of my invention from such accidental fabrics, it is to be understood that the fabric of my invention has a uniform appearance, and an appearance which it was intended to have (referred to as a quality knitted pile fabric). Furthermore, while prior art accidental fabrics may have had a limited number of plain, non-fiber courses, the fabrics of my invention have such courses uniformly distributed over a length of fabric having thousands of courses, e.g., at least 10,000 courses. A uniform distribution of courses of the type under consideration refers to a basic pattern which is repeated over and over again. For example, if in the machine of FIG. 3 yarn-feed station Y3 is omitted (with the fiber-feed rate at one or both of

stations

3 and 4 being reduced), the basic repeated pattern would have seven courses.

The machines described thus far produce a fabric of a single color. But it is often desirable to produce fabric having walewise pattern effects. This can be achieved by providing a needle-selection capability, although this generally results in a decreased capacity. Such a prior art machine configuration is shown in FIG. 4.

Here, the first and third fiber-feed stations feed white fiber to the needles which pass by them, and the second and fourth fiber-feed stations feed black (B) fiber to the needles which pass by them. Each station is equipped with a respective needle-selection device NS1-NS4. There are several conventional types of needle-selecting mechanisms. Each such mechanism raises only selected needles as all of the needles pass in succession by the respective stations. Thus at each fiberfeed station, only selected needles have fibers placed in their hooks. In addition to the use of needle-selecting mechanisms, the Y1 and Y3 yarn feeds in the machine of FIG. 4 are not used. This. necessarily reduces the capacity of the machine by a factor of two, since only two courses are made during each cylinder revolution. However, vertical stripes in the fabric can be formed.

If the 12 needles around the cylinder of the machine of FIG. 4 are considered to be numbered in sequence 1-12, needle-selecting mechanisms NS1 and N83 cause only needles 1-3 and 7-9 to be raised, while needleselecting mechanisms NS2 and NS4 cause only needles 4-6 and 10-12 to be raised. As the 12 needles pass by fiber-feed station 1, needles 1-3 and 7-9 are provided with white fiber. Because no yarn is fed at yarn station Y1, no stitches are formed and the white fiber simply remains in the hooks of these needles. These six needles are then lowered. As the 12 needles then pass by the second fiber-feed station, needle-selecting mechanism N82 causes only needles 4-6 and 10-12 to be raised. These needles are then furnished with black fiber. As they leave the second fiber-feed station, needles 4-6 and 10-12 are already raised. Although needles l-3 and 7-9 are low (so that they do not pick up black fiber at fiber-feed station 2), the cams at yarnhalf-revolution is that a single course in the fabric is formed. This is shown by row Y2 to the right of FIG. 4. The same thing happens as the twelve needles pass by fiber-

feed stations

3 and 4, and yarn-feed station Y4.

It is thus apparent that with needle-selecting mechanisms, walewise patterns can be achieved. In the hypothetical example under consideration, the twelve stitches in each circular course alternate in groups of three, and the fabric contains four stripes of alternating colors. The color effect is achieved, however, at the expense of reducing the capacity of the machine because two of the yarn feeds are not used.

The machine depicted in FIG. 5, also a prior art configuration, is designed to double the capacity of the machine of FIG. 4, that is, to achieve the original capacity of the machine of FIG. 2. The machine of FIG. 5 is the same of that of FIG. 4 except that yarn is fed at stations Y1 and Y3. At fiber-

feed stations

1 and 3, the needleselecting mechanisms still control white fiber to be fed only to needles 1-3 and 7-9, while the needle-selecting mechanisms at fiber-

feed stations

2 and 4 still control black fiber to be fed only to needles 4-6 and 10-12. But in addition to all twelve needles forming stitches at yarn-feed stations Y2 and Y4, all 12 needles now form stitches at yarn-feed stations Y1 and Y3 as well.

As the needles leave fiber-feed station 1, only needles 1-3 and 7-9 are raised. The cams at yarn-feed station Y1 cause the six lowered needles to be raised so that all twelve needles can form a stitch. Since needles 4-6 and 10-12 do not contain fiber in their books, the resuiting course formed at yarn-feed station Y] is of the form shown in the drawing, namely, alternating groups stitches with black pile fiber. During the second half of the revolution courses Y3 and Y4 are formed in the same way. The net effect is a striped pattern. and when each fiber station is made to feed twice the fiber which is fed by the stations in the machine of FIG. 4, the fabric made by the machine of FIG. 5 will have the same appearance and be of the same quality as the fabric made by the machine of FIG. 4. The advantage of the machine of FIG. 5 is that a striped pattern can be made with no loss in capacity. However, there is no increase in capacity vis-avis the original machine of FIG. 2.

The machine of FIG. 5 is to be distinguished from machines made in accordance with the principles of my invention; the machine of FIG. 5 does not have at least two yarn feeds with no fiber-feeding device between them. Also, the fabric produced by the machine of FIG. 5 is to be distinguished from the fabric produced in accordance with the principles of my invention; the fabric depicted in FIG. 5 does not have any plain-yarn courses all around the circumference of the circular knitted fabric.

When additional yarn feeds are added to the machine of FIG. 5 in accordance with the principles of my invention, the capacity of that machine can be doubled, although the fabric produced in not of the same quality. Such a machine is shown in FIG. 6, which depicts four additional yarnfeeds Y1-Y4. Each needle forms a stitch as it passes one of the additional yarn-feed stations, and consequently the resulting fabric has four plain-stitch courses as shown in the drawing. Although the capacity of the machine is thus doubled, the quality of the fabric produced is poor. This is because there are as many as three successive stitches in the walewise direction without pile fiber, and the appearance of the fabric cannot duplicate that of a fabric having pile fiber in every stitch, even if the fiber feed rate in the machine of FIG. 6 is four times the fiber feed rate in the machine of FIG. 2. Even if yarn stations Y1 and Y3 (or Y2 and Y4) are omitted so that there are at most two successive non-fiber stitches in the walewise direction, the quality of the fabric is degraded. I

It will be recalled that the prior art machine of FIG. 5, as well as its modification in accordance with the principles of my invention shown in FIG. 6, evolved from the prior art machine of FIG. 4. The machine of FIG. 4 is basically the same as the machine of FIG. 2, except that two fiber-feed stations (for supplying different-type fibers) are provided between successive yarnfeed stations. and a needle-selecting mechanism deter mines which needles pick up which fibers. As an alternative to the machine of FIG. 4, there is another type of prior art machine which also is capable of producing fabric with walewise patterns. but without requiring a reduction in capacity.

This alternative prior art machine is shown symbolically in FIG. 7, and is described in detail in U.S. Pat. No. 3,413,823 issued on Dec. 3, 1968 to Beucus et al. The machine has four fiber-feed stations with a needleselecting mechanism associated with each, just as does the machine of FIG. 4. However, instead of being equipped with only two yarn feeds, the machine has four yarn feeds. The second major difference between the machines of FIGS. 4 and 7 is that in the latter two different fibers are supplied at each fiber-feed station. The machine includes a split doffer. On each half of the doffer a different type of fiber can be fed to passing needles. Each needle-selecting mechanism determines the type of fiber picked up by each needle as it passes the single associated fiber-feed station.

In FIG. 7, the W and B symbols at each fiber-feed station are intended to show that white and black fibers are fed continuously to separate halves of the doffer. This is to be distinguished from conventional clutch arrangements for selecting the type of fiber to be supplied at each fiber-feed station. Many pile-fabric knitting machines are provided with two silver-feed mechanisms for the single doffer at each fiber-feed station. Depending on the position of a clutch (which can be automatically controlled) one or the other of two slivers is fed via a doffer to those needles which are raised as they pass the station. This type of sliver selection allows control of stripes in the horizontal (circumferential) direction of the finished fabric. It is because the fiber feed cannot be changed quickly that the clutch mechanism is not used to control walewise stripes, that is, the fiber which is fed at a particular station cannot be changed fast enough so that successive needles are fed different types of fibers. In general, sliver selection is used to control course stripes, while needle selection is required to control wale stripes (the two of them together permitting checkerboard patterns, and patterns of arbitrary designs, to be produced). In a split-doffer machine, if a clutch mechanism is provided for each half of the doffer, then four different types of fibers can be fed at each station. The arrangement depicted in FIG. 7 does not relate to the clutch mechanism which controls which of two slivers is supplied to each half of the doffer. Instead, the arrangement is intended to show that two fibers are fed continuously, one to each half of the doffer.

Referring back to FIG. 4, it will be recalled that needle-selecting mechanism NSl causes needles 1-3 and 7-9 to be raised while they pass the first fiber-feed station, while the other six needles remain down; conversely, needle-selecting mechanism N52 controls only needles 46 and 9*l2 to be raised as successive needles pass fiber-feed station 2. All of the needles must pass two fiber-feed stations before each of them engages a yarn so that a course of alternating three-stitch white and black groups can be formed. In the machine of FIG. 7, needle-selecting mechanism NSl causes only needles 1-3 and 7-9 to be riased as the needles pass the right half of the doffer, and it causes only needles 4-7 and 9-12 to be raised as the needles pass the left half of the doffer. Consequently, as each of the 12 needles passes the first fiber-feed station, it is provided with its required color fiber. Thus a yarn-feed station may be provided immediately after the split-doffer fiber-feed station. Because it is no longer necessary to omit two of the four yarn feeds, the machine of FIG. 7 can produce fabric at the same rate as the basic machine of FIG. 2, while at the same time permitting walewise patterns to be formed.

It is believed that if the principles of my invention are applied to the machine of FIG. 7, then the rate at which fabric is produced can be doubled without any loss in quality. All that is required, as shown in FIG. 8, is that four additional yarn-feed stations Y1 Y4 be added to a conventional split-doffer machine. As shown in the drawing, the machine of FIG. 7 knits four courses with vertical stripes during each cylinder revolution. When this is compared to the fabric produced by the machine of FIG. 8, it will be noted that courses Yl-Y4 are the same, but successive ones of these courses are separated by plain-stitch courses formed by the needles as they pass yarn-feed stations Y1'Y4'. Consequently, successive courses exhibit either plain stitches in their entireties or fiber-containing stitches in their entireties. There should thus be no loss in quality, provided the fiber feed rates are doubled.

The machines of FIGS. 2 and 3 have a direct correspondence with the machines of FIGS. 7 and 8. Just as the addition of yarn feeds to the machine of FIG. 2 (without needle selection) doubles its capacity, so does the addition of yarn feeds to the machine of FIG. 7 (which is equipped with a split doffer and needle selection) double its capacity. In both cases, the provision of two successive yarn feeds with no fiber feed separating them allows the capacity of the machine to be increased with no sacrifice in quality.

Inasmuch as the machine of my invention is a conventional type knitting machine provided with additional yarn feeds and associated stitch cams, it will be apparent to those skilled in the art, especially in view of the numerous issued patents in the field such as the above-identified Beucus et al patent, that detailed drawings and a particular machine would serve no purpose. However, the basic concept of the invention can perhaps be more clearly understood by considering FIGS. 9 and 10, the former figure depicting symbolically the configuration of those elements necessary for an understanding of the invention which are included in a prior art machine of the type depicted in FIG. 2, while FIG. 10 illustrates symbolically the changes required to achieve the machine depicted symbolically in FIG. 3. The machine of FIG. 9 is provided with several fiber-feed stations, only two of which (F1, F2) are shown. Following each fiber-feed station, there is a respective yarn-feed station, only two of which (Y1, Y2) are shown. A combined fiber-yarn station has a circumferential length symbolized by dimension 15. The needles move in the direction of arrow 19 along cam track 17. The track is symbolic only, it being understood that in a conventional machine various cam surfaces control the raising and lowering of the needles. Each needle rises as it approaches fiber-feed station F1. As it passes the fiber-feeding doffer, the hook of the needle picks up fibers. As the needle exits the fiber-feed station, it engages the yarn at yarn-feed stationYl. The needle is then lowered, and a stitch is formed with the pile fabric being contained in the stitch. The needle then continues to move to the left (typically, it rises slightly and then continues to move on at intermediate level) until it approaches fiber-feed station F2, at which point the needle starts to rise once again.

The machine of FIG. 10 is basically the same as that of FIG. 9 except that track 17 is changed toward the end of each fiber-yarn station so that after the first stitch is formed, each needle rises to the upper level where it engages a new yarn feed at the added station Y1, after which the needle is moved downward to form another stitch. At the end of the downward movement, the needle starts to rise as it approaches fiberfeed station F2. Thus all that is required'to modify the machine of FIG. 9 is to add an additional yarn feed after an already existing yarn feed, and to provide the necessary cam surfaces for controlling stitches with the new yarn. In addition to these mechanical changes, in operating the machine the fiber-feed controlsshould be set so that the rate of fiber feed is greater in the machine of FIG. 10 than in FIG. 9; the fiber in each course of the fabric produced by the machine of FIG. 10 must simulate the fiber contained in two successive courses of the fabric produced by the machine of FIG. 9.

Of the upmost significance is the fact that the invention is not limited to new machines. Instead, the numerous machines already used in the industry can be modified at minimal cost to greatly increase their capacities. The machines now in use have sufficient space separating each yarn feed and the next fiber feed in the direction of needle travel to accommodate a new yarn feed and stitch-forming cam. Consequently, there is no need to re-position the fiber-feed devices.

It is to be understood that the principles of the invention are applicable to a wide variety of machines. For example, they are applicable to machines with needleselecting capabilities, whether the needles are selected by pattern wheels, or by cam tracks which operate differently upon different types of needles (such as is shown in the above-identified Beucus et al patent). Similarly, the invention is applicable to machines which produce vertical stripes some of which contain fibers and the others of which do not. In such a machine, needle-selecting mechanisms control some of the needles not to engage a particular doffer at all, so that when these needles reach the next yarn-feed station they form plain stitches, the resulting fabric exhibiting plain stripes in the wale direction. The addition of a yarn feed to such a machine in accordance with the principles of my invention would produce courses which have plain stitches in their entireties. It is contemplated that even the newest type of machines which have twelve fiber-yarn feed stations can be modified by the addition of twelve yarn feeds because even in these maximum-capacity machines there is more than one inch between successive fiber-yarn stations, and a yarnfeed station requires only approximately one inch along the circumference of the cylinder.

My invention has been found to have particular application to the manufacture of a shearling fabric (a simulated sheep pelt). The fabric is first knitted, then slit open, and then subjected to a series of finishing operations which develop a fabric with a pebbled surface having the desired aesthetic properties. When an eight-feed Wildman Maxi-Pile knitting machine was modified so that sixteen courses were formed during each cylinder revolution, with twice as much fiber being fed at each of the fiber-feed stations as was fed in the unmodified machine, it was virtually impossible to distinguish the old and new fabrics from each other. Another fabric that is especially suitable for production on the machines of my invention is the long pile or shag type of fabric used for coat trim, toys, outerwear and home furnishings. By providing different yarn feed rates for the pile courses and the non-pile courses, that is, by providing different stitch sizes for the two types of courses, the cover of the fabric may be optimized for particular applications. It is also possible to produce fabrics in which stretch yarns are used for the plain feeds, resulting in a stretchable fabric. Thus although the invention has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the application of the principles of the invention. Numerous modifications may be made therein and other arrangements may be devised without departing from the spirit and scope of the invention.

What I claim is:

1. The method of modifying a pile-fabric knitting machine which has alternating fiber-feed and yarn-feed stations in the direction of the needle travel for increasing the rate of fabric production comprising the step of adding a yarn-feed station following at least one yarnfeed station on the machine without providing another fiber-feed station therebetween such that the modified machine contains at least two yarn-feed stations for controlling the formation of respective separate courses arranged one after the other in the direction of the needle travel without any fiber-feed station being positioned therebetween, whereby on the modified machine two courses, only one of which has pile fabric held by its constituent loops, are formed in place of the single course formed on the machine before it is modi fied, which two courses may be controlled to have the same fiber weight per unit area as said single course be increasing the rate at which fiber is fed during the formation of said only one course.

2. The method of modifying a pile-fabric knittin maching in accordance with claim 1 wherein a yarnfeed station is added between each pair of successive fiber-feed stations.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 6,767 Dated June 1975 Inventor(s) Philip A. Dargie It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1, line 59, "or" should read "of".

' Column 3, lines 35-36, "silver" should read "sliver".

Column 4, lines 57-58, "eight-fed (fibereight-feed yarn)" should read'"eightfeed (fiber and yarn)".

. Column 5, line 31, "not" should read "no".

Column 5, line 34, "FIG. 3" should read "FIG. 2".

Column 5, line 36, "2." should read "is".

Column ll, line 12, '"upmost" should read "utmost".

G Column 12, line 43, "he" should read "by".

Signed and Scaled this eighteenth Day Of Norember1975 {SEAL} v Attesl:

RUTH C. MASON C. MARSHALL DANN .IIICSIIHX ()fjuvr (nmmissmm-r of IUH'IHS and Trutlumurkx UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No, 3,886,767 Dated June 3, 1975 Invent0 Philip A. Darqie It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 10, line 54, "fabric should read "fiber" Column 12, line 39, "fabric"should read "fiber" "mashing" should read "machine" Signed and Scaled this twenty-third D 8) Of December I 975 Column 12, line 47 [SEAL]

Claims

1. The method of modifying a pile-fabric knitting machine which has alternating fiber-feed and yarn-feed stations in the direction of the needle travel for increasing the rate of fabric production comprising the step of adding a yarn-feed station following at least one yarn-feed station on the machine without providing another fiber-feed station therebetween such that the modified machine contains at least two yarn-feed stations for controlling the formation of respective separate courses arranged one after the other in the direction of the needle travel without any fiber-feed station being positioned therebetween, whereby on the modified machine two courses, only one of which has pile fabric held by its constituent loops, are formed in place of the single course formed on the machine before it is modified, which two courses may be controlled to have the same fiber weight per unit area as said single course be increasing the rate at which fiber is fed during the formation of said only one course.