US3906749A

US3906749A - Weft storage device for warp knitting machines

Info

Publication number: US3906749A
Application number: US428232A
Authority: US
Inventors: Gunter Frehn
Original assignee: W Schlafhorst AG and Co
Current assignee: Oerlikon Textile GmbH and Co KG
Priority date: 1972-12-27
Filing date: 1973-12-26
Publication date: 1975-09-23
Anticipated expiration: 1992-09-23
Also published as: DD109686A5; IT1000390B; JPS4994960A; DE2263561A1

Abstract

Weft storage device for warp knitting machine having knitting needles at a given location for knitting weft and warp threads into a fabric web, including a first and a second group of holding members spaced from one another at locations at which they are respectively adjacent opposite edges of a fabric web that is being knitted in the machine, the holding members being loopable thereabout by weft threads and being rotatably mounted and revolvable in direction toward the knitting needles; and rotary drive means for the holding members.

Description

United States Patent [191 Frehn WEFT STORAGE DEVICE FOR WARP KNITTING MACHINES [75] inventor: Gilnter Frehn.Monchengiadbach.

Germany [73] Assignee: W. Sehlaihorst & Co.

Mesehlneniabrllt. Monchengladbach. Germany [22] Filed: Dec. 26. i973 [2i] Appl. No.: 428.232

[30] Foreign Application Priority Date Dec. 27. [972 Germany 226356i [$2] [1.8. 66/84 A [5 1] Int. CL'DlMB 23/06; 0048 23/08; D048 23/l0; D048 23/l2 [58] Field of Search 66/85. 85 A. 86. 84 A. 66/83. 84. 87. 88

[56] References Cited UNITED STATES PATENTS 2/l97l Furst 66/84 A l0ll97l Furst 66/84 A [4 1 Sept. 23, 1975 3.6l6.657 ll/l97l Furst 66/84 A 3.620.048 ll/l97l Furst 66/84 A 3.643.47i 2/l972 Furst 66/84 A 3.648.459 3/l972 Furst et al 66/84 A 3.690.l26 9/l972 Relners et al 66/84 A 3.70l.267 10/1972 Furst 66/86 3.705.503 i2/l972 Svoboda 66/84 A 3.732.707 5li973 66/84 A Primary Examiner-Ronald Feldhaum Attorney. Agent. or Firm-Herbert L. Lerner [57] ABSTRACT Well storage device for warp knitting machine having knitting needles at a given location for knitting weft and warp threads into a fabric web. including a first and a second group oi holding members spaced from one another at locations at which they are respectively adjacent opposite edges oi a fabric web that is being knitted in the machine. the holding members being loopable thereabout by welt threads and being rotatably mounted and revolvable in direction toward the knitting needles; and rotary drive means for the holding members.

4 Claims. 5 Drawing Figures US Patent Sept. 23,1975 Sheet 10m 3,906,749

US Patent Sept. 23.1975 Sheet 2 of 2 3906.749

WEFI STORAGE DEVICE FOR WARP KNITTING MACHINES The invention relates to a weft thread storage device for warp knitting machines and. more particularly. to such a device having holding members oppositely disposed on both sides of the edges of a fabric web being knitted in the warp knitting machine. the holding members being rotatably mounted and revoivingin direction toward the knitting needles of the machine. and about which weft threads are looped.

Weft thread storage devices of this general type continuously accept lengths of welt thread drawn out in the form of loops. which are. for example. unwound from a stationary supply reel. The weft thread storage device feeds the lengths of weft thread to the knitting tools which attend to the continuous intermeshing of the weft threads with the fabric.

For this purpose. a device has become known heretofore. wherein the rotatably supported holding members over which the weft threads are looped are constructed in the form of rolls which are supposed to effect a reduction in the large frictional stress of the weft thread material. This is also to apply particularly when several threads rubbing against each other are to be inserted or fed. Through the introduction of the rolls. the use of a lubricant which reduces the coefficient of friction of the thread is furthermore supposed to be rendered unnecessary.

The disadvantage of the foregoing herctobeforeknown device. how. ever. is that a weft thread loop sliding from the roll-shaped holding members toward the knitting tools at the moment of the transfer of the weft thread. forms a rather long length of free thread because of the dimensions of the rolls and the distance between the drawn-out weft thread lengths. whichleavcs rather messy web edges or sclvagc having long. loosely dangling loops of thread. These loose loops of thread become yet many times longer. if several weft threads are fed to the holding members simultaneously in the form of a weft thread bunch and if. in the cause of the operation. the individual weft thread loops must be placed around more than one of the holding members. The appearance of a selvage with long loop ends produced in this manner is not only poor. but such a selvage also makes more difficult subsequent passes or operations wherein the web of material or fabric must continuously run through machines for finishing or similar purposes. Furthcmtore. due to such long loops. an unnecessary increase in the consumption of valuable weft thread material is produced.

it is accordingly an object of the invention to provide a weft storage device for warp knitting machines that eliminates the disadvantages described hereinabove of heretofore known weft storage devices for warp knitting machines.

With the foregoing and other objects in view. there is provided in accordance with the invention. weft storage device for a warp knitting machine having knitting needles at a given location for knitting weft and warp threads into a fabric web. comprising a first and a second group of holding members spaced from one another at locations at which they are respectively adjacent opposite edges of a fabric web that is being knitted in the machine. the holding members being loopable thereabout by weft threads and being rotatably mounted and revolvable in direction toward the knitholding members. whereby, depending upon the peripheral speed and the nature of the surface of the hold ing members. a tensile force is exerted on that strand of the weft thread which becomes slack when the weft thread is transferred to the knitting tools.

in accordance with another feature of the invention. the rotary drive means comprise a plurality of pressure members frictlonally engaged with the holding members. Such pressure members can abut the periphery of the holding members. clamp or grip the weft thread looped around the latter, and be driven in such a manner that the tensile force acting on the weft thread is reinforced to any extent desired. and. in fact. freed loop sections are stored.

in accordance with a further feature of this invention. the rotary drive means comprise a plurality of stationary pressure members associated with the revoivin g holding members.

The rotary drive means having stationary pressure members assures. in a particularly simple, operationally reliable and economically favorable manner. that the individual holding members roll on the stationary pressure members in the direction toward the knitting tools completely synchronously with a continuous or even stepwise motion of the rotatably mounted holding members. and specifically, as with the rotary drives hereinbefore described. in direction toward the knitting tools against the feeding movement of all the holding members that are mounted on a disc. a chain drive or the like. Since there is looped around one or more holding members. a length of thread of the weft between each holding member and the pressure members. the length of thread. which is released when a weft thread loop slides off the holding member, is transported back against the direction of withdrawal of the weft thread or threads. and thus the thread of a weft thread loop is reliably shortened to the absolutely necessary length. Since the lholding members on the one side of the knitted web are furthermore forced to rotate in opposite direction to those on the other side of the knitted web. a length of thread consumed on theone side of the edge of the fabric web of material is returned to the same extent by the opposite holding members. The result thereof is that a bunch of threads located in the weft thread storage device is always maintained in stretched condition. Also. in the case of a break in a weft thread. the pressure members prevent uncontrolled unwinding of slack sections of the weft thread from the weft thread storage device.

For optimal adaptation to very different thread materials and in order to compensate for possible occurring velocity differences between the rotating holding members. there are provided in accordance with yet another feature of the invention. resiliently and temporarily liftable pressure members mounted on the stationary pressure members.

An especially slippage-free yet thread-protecting transport of the weft thread material is achieved in an advantageous manner when. in accordance with an added feature of the invention. the pressure members are formed of elastic material.

Other features which are considered as characteristic for the invention are set forth in the appended claims.

Although the invention is illustrated and described herein as embodied in weft storage device for warp knitting machines, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.

The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the lullo ing description of specific embodiments when read I connection with the accompanying drawings, in \vhic FIG. I is a side elevational view of one of the discs at ofa weft storage device according to the invention that are disposed on both sides of the edge of a web of goods, and including various other essential parts;

FIG. 2 is a fragmentary view of FIG. 1;

FIG. 3 is a cross-sectional view of FIG. 1 taken along the line llI--III in direction of the arrows;

FIG. 4 'is a top plan view, rotated clockwise through 90, of the weft thread storage device of FIG. I', and

FIG. 5 is a perspective view of the weft thread storage device with feeding members for the weft threads.

Referring now to the drawing and first, particularly, to FIG. 1 thereof, there is shown, in front of a weft thread storage device I constructed in accordance with the invention, the knitting tools of a Raschel or warp knitting machine, including part of a casting-off or knocking-over bar 2, a latch needle 3, eye needles 4 and a comb 5. Warp threads 6 are passed through the eye needles 4, and part of a finished web of material 7 is located adjacent the knocking-over bar 2. The weft thread storage device 1, which is of circular construction in the illustrated embodiment, has two discs 8 disposed opposite each other in the vicinity of the edges of the web of material 7. Like its non-illustrated counterpart, the disc 8 is firmly connected to a driving shaft 9. The weft thread storage device I rotates toward the knitting tools 2-8 in the direction of the arrow I0 in synchronism with the knitting speed during the operation of the machine, so that the weft threads, which are held and separated by the holding members II and 18, can be transferred continuously to the knitting tools by the comb 5, which oscillates back and forth in a conventional manner, so as to be intermeshed. with warp threads.

FIG. 2 shows another phase of this operation particularly clearly in a fragment of FIG. 1. Furthermore, there is shown in FIG. 2, as in FIG. I, one of a plurality of pressure members 12. In the embodiment shown in FIGS. I and 2 the pressure member 12 is a stationary pressure member, which is held in position by two stay bolts 13; the latter. in turn, being securable to a nonillustrated stationary part of the machine frame. By means of hinges l4 visible in FIG. 4, additional pressure members 15, which are mounted so that they can be raised and which normally also abut againstthe 3 11, shown partly in cross section, is in contact with a holding members II and 18 by the action of the torsion liftable pressure member 15. The shortened base 21 of the holding members II can pass the shoulder 19 of the liftable pressure members IS unimpeded. This is also the case for the similar shoulders on the stationary pressure member 12. As mentioned, hereinbefore, only an elongated or lengthened base 28 of the holding members 18 is thus in a position to lift a movable pressure member 15. This lifting or raising action permits equallziation of the tension and the length of the weft threads F should differences in the speeds of the individual holding members oeettr. All of the holding members II and II are relatively easily rotatable on pins 20 that are press-titted into the discs 8, as illustrated by the holding member II shown in FIG. 3. it is further apparent from FIG. 3 that the pressure member 15 is lined with a segment 15' formed of elastic material. The stationary pressure members 12 are similarly lined. The elastic material segments 15' ensure gentle treatment of the weft threads F and simultaneously afford a reliable drive of the holding

members

11 and 18. The pressure members I2 and 15 can, of course, also be formed completely of a dimensionally stable but nevertheless elastic material. In FIG. 3 as well as in FIG. I, there are shown particularly clearly several spacers 36, which are affixed to the inside of the discs Band which ensure the requisite pitch separation for the threads, even when the diameter of the holding member is relatively small. The number and distribution of the spacers 36 on the periphery of each disc 8 depend upon the number of weft threads that are to be fed in or inserted simultaneously.

In FIG. 4 there is shown how a weft thread bunch, formed of four

different weft threads

22, 23, 24 and 25, is placed continuously and in loop-fashion around the holding

members

11 and 18. it is clearly apparent from FIG. I that each of the weft threads 22 to 25 is looped around four holding members and must thereby form a weft thread loop of corresponding size. By means of the

arrows

26 and 27, there is. clearly shown in FIG. 4 how the Individual threads of such a thread bunch are altematlngly transported back as soon as they, with the holding members If and I8, come into the vicinity of the

pressure members

15 and 12. The illustration in FIG. 4 seeks to clarify how the excess weft thread length in the vicinity of the weft thread loops is re moved, so that the closed loops 29 remaining at the selvage of the material do not overhang but exhibit the normal size otherwise attainable only in woven goods.

In FIGS. 1, 2 and 4 there can further be seen a holddown device 30 which is swingable out above the weft threads F and which ensures correct positioning of the weft threads up to the direct transfer from the holding devices to the comb 5. The hold-down device 30 is a bent-away part of a bell crank or double-arm lever 35 which is pivotable about the axis of the drive shaft 9. The swinging or pivoting motion of the hold-down device 30 is produced in synchronism with the knitting speed by a cam 32, against which a roller 31 abuts under the biasing action of a tension spring 34 suspended at one end from an extension arm 33 and affixed to the machine frame at the other end thereof.

In FIG. 5 there are shown, in addition to the parts of the weft thread storage device I according to the invention, which were aforedescribed with respect to FIGS. 1 to 4, parts of a device previously alluded to for feeding-in or inserting the weft thread bunch formed or the four weft threads 22 to 25. This inserting device is formed essentially of a profiled tube 39, in which a pro jectile 38 is shot back and forth by a current of compressed air. The projectile 38 carries a sliding member 37, which pulls the four weft threads 22 to 25 off stationary supply reels, not illustrated in the drawing. At the reversal points of the sliding member 37, the weft threads 22 to 25 are placed altematingly around the holding

members

11 and 18. respectively, of the two discs 8 by means of feed or insert hooks employed in the aforementioned disclosed and described embodiment of the invention, and which have been represented, in the figures showing the embodiment, only b arrows for the sake of greater clarity.

in the claims:

I. Weft storage device for a warp knitting machine having knitting needles at a given location for knitting wefl and warp threads into a fabric web, comprising a first and second group of holding members spaced from one another at locations at which they are respectively adjacent opposite edges of a fabric web that is being knitted in the machine, said holding members being adapted to carry loops of weft threads and having rcspectlve axes about which they are rotatable, said holding members being disp laceable along a given path in direction toward the knitting needles; and rotary drive means for said holding members. said rotary drive means comprising a plurality of pressure members mounted adjacent said given path and having means for frictionally engaging said holding members so as to produce rotation of said holding members about the respective axes thereof as said holding members are displaced along said given path.

2. Weft storage device according to claim 1 wherein said pressure members associated with said revolvable holding members are stationary.

3. Weft storage device according to claim 2 including resiliently'and temporarily liftable pressure members mounted on said stationary pressure members.

4. Welt storage device according to claim 3 wherein said pressure members :are formed of elastic material. i i i i

Claims

1. Weft storage device for a warp kniTting machine having knitting needles at a given location for knitting weft and warp threads into a fabric web, comprising a first and second group of holding members spaced from one another at locations at which they are respectively adjacent opposite edges of a fabric web that is being knitted in the machine, said holding members being adapted to carry loops of weft threads and having respective axes about which they are rotatable, said holding members being displaceable along a given path in direction toward the knitting needles; and rotary drive means for said holding members, said rotary drive means comprising a plurality of pressure members mounted adjacent said given path and having means for frictionally engaging said holding members so as to produce rotation of said holding members about the respective axes thereof as said holding members are displaced along said given path.

3. Weft storage device according to claim 2 including resiliently and temporarily liftable pressure members mounted on said stationary pressure members.

4. Weft storage device according to claim 3 wherein said pressure members are formed of elastic material.