US2441189A

US2441189A - Warp knitting machine

Info

Publication number: US2441189A
Application number: US697987A
Authority: US
Inventors: Richard F Eshleman
Original assignee: American Viscose Corp
Current assignee: Akzo Nobel UK PLC
Priority date: 1945-12-05
Filing date: 1946-09-19
Publication date: 1948-05-11
Anticipated expiration: 1965-05-11

Description

May 11, 1948. R. F. ESHLEMAN WARP KNITTING MACHINE 2 Sheets-Sheet 1 Original Filed March 27, 1945 May 11, 1948. ESHLEMAN 2,441,189

WARP KNITTING MACHINE Original Filed March 27, 1945 Z-Sheets-Sheet 2 IN EN TOR. @MxmM Patented May 11, 1948 WARP KNITTING. MACHINE Richard F. EshlemamWest Chester, Pa., assignor to American Viscose Corporation, Wilmington, DeL, a corporation of Delaware Y Continuation of application Serial No. 585,052, March 27, 1945. This application September 19, 1946, Serial No. 697,987. In Great Britain December 5, 1945 This invention relates to warp or tricot knitting machinery and is particularly concerned with arrangements for feeding the yarns from the Warp beams or sectional warp beams under controlled tension to the needles of the machine. This is a continuation of an application now abandoned, filed March 27, 1945, Serial No. 585,052.

In the conventional warp knitting machine, the threads are drawn from the warp beam by pulling action initiated by the needles themselves. The warp beam is associated with a suitable brake or equivalent mechanism whereby it is released for rotation whenever the needles or other knittin elements, such as the guides, call for thread, and whereby it is secured against rotation in the intervening periods. This arrangement has various disadvantages, the most important of which being the limitation of the speed at which the machine may operate. Since the feeding of thread is dependent upon the release of the brake in response to increase in tension of the yarns, it is apparent that the thread feeding tends to lag behind the knitting element or needle requirements. This lagging effect gives rise to a wide variation in the tension which becomes most pronounced at high speed and definitely limits the maximum speed at which satisfactory fabrication can be effected. There have been various suggestions to provide for positive feeding of the yarn independently of the drawing action of the needles but none of the suggested arrangements has been found to be practical. For example, it has heretofore been proposed to intermittently drive the yarn supply beams independently of the needles but such intermittent motions are not adaptable to high speeds.

In accordance with the present invention, the supply beams for a given warp are rotated continuously at the same constant peripheral (yarn periphery) speed and there is provided between the feeding means and the knitting elements a positively driven means for varying the path of the yarns in timed relation to the knitting cycle so that when the knitting elements draw a thread at a greater linear speed than the delivery speed of the feeding means, the length of the yarn path is decreased proportionately to make up the additional length of yarn needed by the elements and when the requirements of the elements are less than the rate of feed from the supply means, the. yarn will take a longer path, thereby compensating for the discrepancy between the constant feeding rate and the varying requirements during the knitting cycle. This positively driven means may be associated with, or entirely independent 16 Claims. (Cl. 6.686)

of, the tensioning devices, such as the conventional tension bars and may advantageously take its movement from the cam shaft of the knitting machine which controls the knitting cycle.

In the drawing, illustrative of the invention- Figure 1 is a somewhat diagrammatic end view (partially in cross-section) of a machine embody-f ing the present invention,

Figure 2 is a back elevational view of the embodiment of Figure 1,

Figure 3 is an end view of a modification,

Figure 4 is an end view of another modification, and l I Figures 5 to 8 illustrate the knitting cycle.

For the purposes of illustration, the invention is shown in connection with a two-warp machine though it may be used with a single warp, a triple warp or higher warp machine. All of such machines comprise the guides G and G the needles N, the sinkers S, all of which constitute the'insides or knitting elements-0f the machine, and the presser bar P. The needles, guides, presser and sinkers are mounted on corresponding bars which partake of motions controlled by various cams disposed on the cam shaft of the machine driven by a motor in the conventional manner.

In a warp knitting machine of the-typeshown in Figures 1 and 2, the knitting cycle comprises generally the following sequence of steps taken by the knitting elements referring -to the rela tionships shown in Figure 5- as the starting position. In Figure 5, the guides G and G are in their forward position in front of the needles N which are in their lapping position of intermediate height with their shanks extending through the most recently formed loops of the fabric F. As shown in Figure 6, the guides-move back of the needles and then move laterally to lap their threads around the needles. Then the guides return to their forward positions to complete the loops around the needles at which time the needles rise to their uppermost position to place the new loops under their beards. As the needles start downwardly, the presser bar P moves forward to close the beards of the needles over these loops andthe sinkers S move back somewhat so that the relative positions of Figure 7 are reached. Thenthe needles continue to'move downwardly toidraw ,the' new. loops within the closed beards through the previously formed loops.

this position, the needles rise-to lapping position,

as shown in Figure 5.

It will thus be seen that there arecer'tain in tervals of time when the needles require thread and others when they do not. The chief demand for thread is during the time that the new loops are drawn downwardly by the needles through the old loops. Immediately after this period 'of the knitting cycle, until the needles have risen again to their lapping position there is no demand for thread whatsoever. When the guides lap the threads about the needles, there is some demand by the guides for thread which may be of less, comparable, or greater magnitude than the demand when the new loops are drawn through the old loops depending upon the number of needles about which the loops are formed.

Referring particularly to the embodiment of Figures 1 and 2, both the upper and lower tiers of sectional warp beams 2 for supplying front and back warps respectively are mounted for free rotation and are supported upon pairs of parallel rolls 3 which are driven in synchronism. The rolls-may have cork or rubber surfacesto ive good ffhctional driving contact with'the periphera? windings of yarn on the beams without abrasion thereof; As shown, the pairs of rolls are driven by sprocket and chain connections wan the common shafts 4 extending the length of the machine. The common driving shaft 4 for each warp supply is connected to that of each of the others, such as by the 5 and sprocket connection shown, the sizes of the sprockets 6 and 1 being predetermined in. retaticn to the speed or'take-up to produce definite ratio of yarn speed in the several warps. This ratio may be varied widely depending upon the pattern of fabric desired. For driving the common-shafted a chain 8 and sprocket connection with tnemctor a may be used and it isadvantageous to provide an infinitely variable speed reducer -I Fbetween' the motor 9 and the sprocket for driving chain 8 in order to obtain any desired feeding speed. The motor 9 for driving the yarn-feeding rolls may be the same as that for driving the cam shaft of the machine, as shown, or separate motors may be used if desired. As the yarns proceed from each warp supply, they proceed about the tension bars H and thence to thegoides G" and and needles N. The tension bars maybe carried in conventional fashion upon pivotally mounted levers 1 2 provided at each end thereof, each lever having an arm is agafnstwhich a, spring i exerts a pressure in opposition to-the'tendency of any sudden development of tension in the yarns to move the tension bars downwardly.

The cam shaft [5 is provided with the conventionai' cams and the machine has the conventional followers for transmitting the motion to the various knittingelementssuch as the needles, guides and sinkers as well as to the pres'ser bfar associated therewith. These various cams and cam fol-lowers may be conventional and hence are not shown. In accordance with the present invention, however; the cam shaft is also provided with cams [6 which are associated with the followers IT comprising the pivoted levers H? and the rods [9 connected thereto. The rods areconnectedby a pin and slot joint to the levers i2 carryingthc tension bars. A separate cam 18 and cam follower system H is rovided for each warp tension bar I I. These cams l6 positively'vary'the paths taken bythe warp sheet withiwhich they are associated and while their shape mayvary' widely depending upon the particular fabric pattern desired, they are functionally reiated tothe cams of the knitting elements and particularly the needles so that the path taken by the yarns in the warp sheet is decreased when there is a demand for yarn by the needles and/or guides in excess of the normal rate of supply by the respective warp supply beams and increases thepath when the reverse relationship between the supply rate and the knitting requirement occurs during the knitting cycle. Preferably, the cams are of the split variety which are readily removable from the cam shaft without dismantling the machines so that. they may be replaced with cams of other patterns to provide other fabric patterns.

The arrangement of the embodiment of Figures 1. and 2 is such that there is no interference with the spring-tensioning action of the tension bars and there isa variation in the yarn path imparted to the yarns of each warp, superimposed on the normal variation resulting from changes in tension, by the positive movement of the tension bars imparted by the cam shaft in timed relation to the knitting cycle. The connection of the rods [9 with the levers I 2 supporting the tension bars comprises a pin and. slot connection so that even when the tension bar supporting levers are moved positively they are still responsive to any increase in tension imparted to the yarn regardless of the cause thereof.

Figure 3 shows a modification in which the sectional beams 2 are supported in a guideway fit within which they are vertically movable and are carried. with their yarns in direct contact with the driving rolls 3a directly therebeneath, a single roll being used in each case instead of the two rolls of the embodiment of Figures 1 and 2. The cam shaft l5 drives a chain 22 which in turn drives a rotatable rod 23 having an eccentric yarn-engaging surface extending the length of the warp sheet so that as this eccentric rod rotates, the paths of the yarns in the warp sheet are increased and decreased at predetermined intervals, the sprockets 24 being of the same size so that the variation in the yarn path occurs in timed relation with the knitting cycle and has the same period as such cycle. Preferably, the eccentric 23 is so rotated that its surface moves in the same direction as that of the yarn in contact-therewith.

As: shown in- Figure l, the. supply beams 2 (only one being shown) may be driven positively by means of one or more supporting belts 25 carried and driven by rollers 26, a guideway 2| (similar to that of Figure 3) being provided at each end of the beam to allow it vertical movement in response to change of diameter.

While the embodiment of Figures 1 and 2 shows two warps and those of Figures 3 and 4 show one "warp, it is to be understood that the invention is applicable to machines using any number of warps. In all cases, all tension bars. are positively moved in timed relation to the knitting cycle. While in special cases, all the tension bars may take their movement from a single cam and follower system, in order to obtain the widest variety of fabric patterns, it is preferable to use a separate cam and follower system for each tension bar.

The present invention makes it possible to uniformly feed the yarns under controlled tension to the knitting elements. Whereas heretofore the fabric pattern or quality depended a great deal upon the adjustment of the tension bars and the toughness of the springs associated therewith, and such adjustments were not readily duplicable, the present invention makes it possible to determine the quality of fabric before any cloth is knitted and to duplicate a given quality of fabric simply by setting the take-up speed, at least one of the warp speeds, and the ratio between the warp speeds. 'I'hemovements of the various machine elements are continuous so that the present invention is adaptable to those machines in which high speeds are desired. In addition, the positive control of the yarn path in timed relation with the knitting cycle, Without relying on the drawing action of the needles to vary the yarn path or the speed of the warps, assures smooth operation without the development of sudden increases or decreases in tension.

It is to be understood that changes and variations may be made without departing from the spirit and scope of the invention as defined in the appended claims.

I claim:

1. In a warp knitting machine, knitting elements comprising guides and needles, a cam shaft for controlling the knitting cycle of the elements, at least one warp supply beam, means for continuously feeding yarn for a predetermined warp from the supply therefor at a predetermined constant speed, and means engaging the yarn proceeding from the supply thereof before it reaches the guides for varying the length of the path of the yarn from the feeding means to the elements in timed relation to the knitting cycle to substantially compensate for discrepancies between the constant feeding rate and varying yarn requirements of the elements during the knitting cycle.

2. In a warp knitting machine, knitting elements comprising needles, a cam shaft for controlling the knitting cycle of the elements, at least one warp supply beam, means for continuously feeding yarn for a predetermined warp from the supply therefor at a predetermined constant speed, and positively driven means for varying the length of the path of the yarn from the feeding means to th elements in timed relation to the knitting cycle to substantially compensate for discrepancies between the constant feeding rate and varying yarn requirements of the elements during the knitting cycle.

3. In a warp knitting machine, knitting elements comprising needles, a cam shaft for controlling the knitting cycle of the elements, at least one warp supply beam, means for continu-- ously feeding yarn for a predetermined warp from the supply therefor at a predetermined constant speed, spring means for tensioning the yarn between the feeding means and th needles, and positively driven means for varying the length of the path of the yarn from the feeding means to the elements in timed relation to the knitting cycle to substantially compensate for discrepancies between the constant feeding rate and varying yarn requirements of the elements during the knitting cycle.

4. In a warp knitting machine, knitting elements comprising needles, a cam shaft for controlling the knitting cycle of the elements, at least one warp supply beam, means for continuously feeding yarn for ,a predetermined warp from the supply therefor at a predetermined substantially constant speed, spring means for tensioning the yarn between the feeding means and the needles, and positively driven means associated with the tension means for varying the length of the path of the yarn from the feeding means to the elements in timed relation to the knitting cycle to substantially compensate for discrepancies between the constant feeding rate and varying yarn requirements of the elements during the knitting cycle, the positively driven means being arranged to impose its effects on the tension means in opposition to the spring means.

' 5. In a Warp knitting machine, knitting elements comprising needles, a camshaft for controlling the knitting cycle of the elements, at least one warp supply beam, means for continuously feeding yarn for a'predetermined warp from the supply therefor at a predetermined substantially constant speed, and means driven by the cam shaft for varying the length of the path of the yarn from the feeding means to the elements in timed relation to the knitting cycle to compensate for discrepancies between the constant feeding rate and the varying yarn requirements of the elements during the knitting cycle.

' 6. In a warp knitting machine, knitting elements comprising needles, a cam shaft for controlling the knitting cycle of the elements, at least one driven roll, a warp supply beam adapted to rest with its peripheral windings on said roll so as to be driven thereby, means for driving said roll at constant speed to feed yarn therefrom, and means driven by the cam shaft for varying the length of the path of the yarn from the feeding means to the elements in timed relation to the knitting cycle to compensate for discrepancies between the constant feeding rate andvarying yarn requirements of the elements during the knitting cycle.

'7. In a warp knitting machine, knitting elements comprising needles, a cam shaft for con trolling the knitting cycle of the elementsat least one Warp supply beam, means for continuously feeding yarn for a-predetermined warp from the supply therefor at a predetermined substantially constant speed, a tension bar for tensioning the yarn between the feeding means and the needles, and means driven by the cam shaft and connected to the tension bar for moving said tension bar in timed relation to the knitting cycle to substantially compensate for discrepancies between the constant feeding rate and the varying yarn requirements of the elements during the knitting cycle. 1 1

8. In a warp knitting machine, knitting elements comprising needles, a cam shaft for controlling the knitting cycle of the elements, at least one warp supply beam, means for continuously feeding yarn for a predetermined warp from the supply therefor at a predetermined substantially constant speed, a resiliently mounted tension bar for tensioning the yarn between the feeding means and theneedles, such tension bar being connected to and driven by the cam shaft in timed relation to the knitting cycle to substantially compensate for the discrepancies between the constant feeding rate and the 'varying' yarn requirements of the elements during the knitting cycle.

9. In a warp knitting machine, knitting elements comprising needles, a cam shaft for conv trollingthe knitting cycle of the elements, a plurality of supply beams for feedingyarns to a plurality of warps, means for continuously feeding yarn for each warp fromthe supply therefor at predetermined substantially constant speeds, means for adjusting the ratio between such speeds, and means driven by the cam shaft for varying the length of the path of the yarn in each of the warps from the feeding means to the elements in timed relation to the knitting cycle to substantially compensate for discrepancies between the constant feeding rate and vary- 7 ing yarn requirements of theelements during the: knitting: cycle;

10. In a warp knitting machine, knitting elements comprising needles, a cam shaft for controlling; the knitting cycleqofi the elements, a pair of substantially parallel driven rolls, a warp supply beam adapted to rest with its peripheral windings, on said roll so as to be driven thereby, means for driving at least one of said rolls at constant speed to supply yarn from the warp supply, and. means driven bythe cam shaft for varying the lengthof the path of the yarn from the feeding means to the elements in timed: relation to the, knitting cycle to compensate for discrepancies between the constant feeding rate and varying yarn requirements of the elements during the knitting cycle.- v Y 11. In a warp knitting machine, knitting elements comprising needles, a cam shaft for controlling the knitting cycle of the elements, a pair of substantially parallel rollers, at least one belt carried about said rollers, a'warp supply beam adapted to rest with its peripheral windings on the belt or belts so as to be driven thereby, means for driving said belt at constant speed to supply yarn from the warp supply, and means driven by the cam shaft for varying the length of the path of the yarn from the feeding-means to the elee ments in timed relation to the knitting cycle to compensate for discrepancies between the constant feeding rate and varying yarn requirements of the elements during the knitting cycle.

12. In a warp knitting machine, knitting elements comprising needles, a cam shaft for con; trolling the knitting cycle ofthe elements, at least one driven roll, a warp supply beam adapted to rest with its peripheral windings on said roll so as to be driven thereby, means for driving said roll at constant speed to feed yarn from the supply, and a roller driven by the cam shaft having an eccentric surface engaging the yarns proceeding from the warp supply beam for varying the length of the path ofthe yarn from the feeding means to the elements in timed relation to the knitting cycle to compensate for discrepancies between the constant feeding rate and varying yarn requirements of the elements during the knitting cycle. 1 I

13. In a warp knitting machine, knitting elements comprising guides and needles, a cam shaft for controlling the knitting cycle of the elements, at least one warp supply beam, means for continuously feeding yarn for a predetermined warp from the supply therefor at a predetermined substantially constant speed, said feeding means comprising at least oneroll and means for rotating the roll at constant speed, said feeding means being arranged to support the beam associated therewith with some of its peripheral windings resting thereon so as to make driving engagement therewith, and means engaging the yarn proceeding from the supply thereof before it reaches the guides for varying the length of the path of the yarn from'the feeding means to theelements in timed relation to the knitting cycle to substantially. compensate for discrepancies between the constant feeding rate and varying yarn requirements of the elements during the knitting cycle.

14-. In.;a warp knittingv machine; knitting: ale.- ments comprising-needles, acam shaft for controlling" the knitting cycle of the-elements; at least one warp; s upply beam, -means for contin uously feeding yarn for a predetermined warp from the supply therefor ata predeterminedsube stantially constant speed, said feeding means comprising at least one roll and means for rotating the roll at constant speed, said feeding means being arranged to support the beam associated therewith with some of its peripheral windings resting thereon so as to make driving engagement therewith, and positively driven means for varying the length of the path of the yarn from the feeding means to the elements in: timed relation to the knitting cycleto substantially compensate for discrepancies between the constant feeding rate and varying yarn requirements of the elements during the knitting cycle.

15. In a warp knitting machine, knitting elements comprising needles,- a cam shaft for, controlling the knitting cycle of the elements, at least one warp supply beam, means for continuously feeding yarn for a predetermined Warp fromthe supply therefor at a predetermined substantially constant speed, said feeding means comprising at least one roll and means for rotating the roll at constant speed, said feeding means being arranged to support the. beamassociated therewith, with some of its peripheral windings resting thereon so as to makedriving engagement therewith, and means driven by the camshaft for varying the length of the path of the yarn fro-m the'feeding means to the, elements in timed relation to the knitting cycle to compensate for discrepancies between the constantfeeding rate and the varying yarn requirements jof. the elements during the knitting cycle.

1'6.'In a warp knitting machine, knitting elements comprising needles, a cam shaft for controlling the knitting cycle of the elements, a plurality of supply beams. for feeding yarns to a plurality of warps, means for continuously feeding yarn for each warp from the supply therefor at predetermined substantially constant speeds, means for, adjusting the ratio between such speeds, each of said feeding means comprising at least one roll and means for rotating the roll, at constant speed, said feeding means being arranged to support the beam associated therewith with some of its peripheral windings resting thereon so as to make driving engagement therewith, and means driven by the cam shaft for varying the length of the path of the yarn in each of the warps from the feeding means to. the elements in timed relation to the knitting cycle to substantially compensate for discrepancies between the constant feeding rate and varying yarn requirements of the elements during the knitting cycle.

- RICHARD F. ESHLEMAN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Name Date