US3799212A

US3799212A - Yarn feeding device for textile machines

Info

Publication number: US3799212A
Application number: US00271129A
Authority: US
Inventors: S Krmela; L Klinecky
Original assignee: Zbrojovka Vsetin np; VYZKUMNY USTAV LYKOVYCH VLAKEN
Current assignee: Zbrojovka Vsetin np; VYZKUMNY USTAV LYKOVYCH VLAKEN
Priority date: 1971-07-14
Filing date: 1972-07-12
Publication date: 1974-03-26
Anticipated expiration: 1991-03-26
Also published as: GB1372325A; FR2145705B1; FR2145705A1; NL7209687A; DE2233116A1; CH550269A; CS152234B1

Abstract

A device for feeding yarns in textile machines, particularly for weft measuring devices in looms with hydraulic or pneumatic weft insertion. The device includes two rotary bodies, one rotary body being constituted by a ring provided with an inner frictional surface and an outer frictional surface, the ring being mounted on a rotary conical driving body. The other rotary body is a yarn pressing disc, the axis of rotation of which is parallel to the axis of rotation of the rotary conical driving body. The ring and the pressing disc form a yarn-forwarding nip between them. The ring and the conical rotary driving body constitute a frictional pair of which at least one member is axially traversable with respect to the other member of said frictional pair.

Description

United States Patent Stanislav et a1.

[11] 3,799,212 1451 Mar. 26, 1974 YARN FEEDING DEVICE FOR TEXTILE MACHINES Inventors: Krmela stanislav; Ladislav Klinecky, both of Sumperk, Czechoslovakia Assignees: Zbrojovka Vsetin, narodni podnik, Vsetin; Vyzkumny ustav Lykovych Vlaken, Sumperk, both of, Czechoslovakia Filed: July 12, 1972 Appl. No.: 271,129

Foreign Application Priority Data July 14, 1971 Czechoslovakia 5168/71 US. Cl. 139/122 R, 226/184 Int. Cl D03d 47/36 Field of Search 139/122 R, 122 H, 127 P;

References Cited UNITED STATES PATENTS 1 1971 Fransen 139 122 3,596,683 8/1971 Dendo 139/122 Primary ExaminerI-Ienry S. .laudon c1 [57] ABSTRACT A device for feeding yarns in textile machines, particularly for weft measuring devices in looms with hydraulic or pneumatic weft insertion. The device includes two rotary bodies, one rotary body being constituted by a ring provided with an inner frictional surface and an outer frictional surface, the ring being mounted on a rotary conical driving body. The other rotary body is a yarn pressing disc, the axis of rotation of which is parallel to the axis of rotation of the rotary conical driving body. The ring and the pressing disc form a yarn-forwarding nip between them. The ring and the conical rotary driving body constitute a frictional pair of which at least one member is axially tra- I versable with respect to the other member of said frictional pair.

25 Claims, 17 Drawing Figures PMENTH] R25 814 SHEEI 3 OF 7 PAIENTEB mzs i974 SHEET 6 OF 7 YARN FEEDING DEVICE FOR TEXTILE MACHINES The present invention relates to a device for feeding yarn in textile machines, particularly for weft measuring devices in looms with hydraulic or pneumatic weft insertion, said device including two cooperating nipforming rotary bodies.

There are known devices for feeding yarn in textile machines which have two nip-forming rotary bodies, of which the lower rotary body is the driving element and the upper rotary body is the pressing element. Each of the rotary bodies has a cylindrical shape with parallel axes of rotation, or each is in the form of a truncated cone, the two truncated cones having converging axes of rotation. In front of and behind'said pair of rotary bodies, a yarn guide is mounted for directing said yarn to the appurtenant point of the nip line of said rotary bodies. Between the feeding device and the yarn supply bobbin there is mounted a yarn brake.

When the bodies are cylindrical, the two yarn guides are mounted stationarily. The velocity of feeding depends in this case upon the diameter of the lower driving cylinder. For the purpose of changing the feeding velocity, the lower driving cylinder is arranged so as to be replaceable or its drive is provided with a transmission mechanism providing a gradually adjustable yarn feeding velocity.

However, the device for feeding yarn with a replaceable lower driving cylinder is not suitable for used in machines requiring a change of yarn velocity during the operation of the machine. The disadvantage of the variable speed transmission consists in high costs and space requirements.

When using a pair of nip-forming truncated cones, the two yarn guides are arranged adjustably along the nip line of the two bodies. The velocity of yarn feeding is adjusted by the position of the yarn guides with respect to the nip line. Upon change of yarn feeding velocity, the yarn is subjected to a lateral traction, which results in higher tension at the nip point of the yarn. This phenomenon might cause either breakage of certain yarn materials, or e.g., with synthetic rayon produce undesired irreversible drafting.

The disadvantage of the nip line between two rotary bodies made between two conical surface lines consists in irregular withdrawing speed caused by oscillation of the yarn along the nip line, namely when the yarn has, e.g., a variable character, as the yarn speed changes along the nip line.

The devices hitherto known for feeding yarn are not suitable for processing flat tapes of plastic material such as polypropylene, polyethylene or modifications of said materials in the form of weft in looms with hydraulic or pneumatic weft insertion, such looms being provided with a weft measuring device located behind the feeding device. I

When axially unwinding the flat tape from the supply bobbin, a false twist is imparted thereto which varies with the diameter of the supply bobbin. Upon passage of the twist through the nip line of the two rotary bodies, the material of said tape is oscillated along the nip line due to its toughness and resilience, giving rise to irregular feeding. As the measuring device operates in dependence upon the fed yarn, or upon tape-length, wefts of different length are formed due to irregular feeding, thus causing long ends in the fabric at the opposite ends of the shed.

The yarn brake frequently causes weft breakage. After accumulation of the' twist in frontof the brake, said twist penetrates the nip line of the brake, which is thus out of action during the time of passage of the yarn therethrough. This phenomenon, which impairs the quality of the fabric thus manufactured, frequently causes yarn collisions in further parts of the weft measuring zone, which usually results in yarn breakage.

The purpose of the present invention is to provide a feeding device of simple construction and high operation reliability which makes possible a quick change of yarn feeding speed during machine operation; this is particularly suitable for use with the weft measuring device in looms with hydraulic or pneumatic weft insertion for weaving with a weft having the shape of a flat tape. The requirements as given above are substantially fulfilled by the device according to the present invention for feeding yarn in textile machines. Such device includes two rotary bodies forming a yam-feeding nip, said device according to the present invention being characterized in that one rotary body is constituted ,by an annulus or ring provided with inner and outer friction surfaces, said annulus being freely mounted on a conical driving rotary body having a diameter which changes from a minimum continuously to a maximum diameter which corresponds to the inner diameter of the annulus. The annulus is brought into rotation by contact of at least a part of the inner friction surface of the annulus with the housing of the driving rotary body. The second rotary body is at least one pressing disc, the axis of rotation of which is parallel with the axis of rotation of the driving rotary body. The annulus and the driving friction body constitute a friction pair, of which at least one element is axially displaceable with respect to the other element of said friction pair.

The driving rotary body may be constituted by a truncated cone, a paraboloid, a hyperboloid, a barrelshaped body, etc. The most suitable shape from the viewpoint of both manufacture and construction is that of a truncated cone.

The pressing disc is rotatably and movably mounted on a carrier in such manner as to be enabled to move away from the annulus, said carrier being provided with at least one means for pressing said pressing disc towards the annulus. The carrier is provided with a fork for holding the annulus in its adjusted operative position.

On the carrier, at least one yarn guide is arranged for bringing the yarn or yarns into immediate proximity of the nip line of the pair of rotary bodies.

According to one basic modification of design of the present device, the carrier is adjustably displaceable on a stationary guideway along an axially stationary driving rotary body, and is provided either with a swingable carrier arm, on which a pressing, disc is rotatably mounted, or a gate, in which there are guided the pins of the pressing disc.

The pressing means is constituted by a spring mounted between the carrier-arm and the carrier, or the pressing means may be a spring arranged on the carrier so as to thrust upon the pins of the pressing disc.

According to another basic modification, the driving rotary body is axially and adjustably displaceable with respect to an axially stationary carrier. The driving rotary body in this embodiment is traversably mounted on a driving shaft and connected in its movement, on the one hand, with this driving shaft, and on the other hand with a control member for adjusting the position of the driving rotary body on the driving shaft. The control element is constituted by a screw and a driver which engages the groove of the hub of the driving rotary body.

At least one rotary body is preferably provided with a friction coating for improving the frictional engagement between the said rotary bodies.

At least one of the pair of rotary bodies is provided with a circumferential groove in which the second body of said pair is guided.

An embodiment of particular advantage is that in which the carrier is made of an annular sleeve mounted contactlessly on a driving rotary body and fastened to a pressing arm swingably mounted on a stationary support; the carrier is stationarily connected to the inner annulus of a ball bearing on which an outer ball bearing ring carrying an annulus is rotatably mounted. The annulus is made of a rectilinear housing which passes over to a one-sided flange with an inner friction surface. The pressing arm is spring loaded for securing a frictional engagement between the annulus and the driving rotary body.

The device according to the present invention makes possible the simultaneous feeding of several yarns. For that purpose, on one of the pair of rotary bodies there is provided a circumferential groove which divides the nip line into two partial nip lines; a collar engages said groove and is mounted on the other rotary body of said pair, to which there is attached a pair of independently controllable yarn guides for selective engagement of the yarn into the partial nip line and disengagement therefrom.

At least two pressing discs can be attached to one annulus. The arrangement of the device according to the present invention for selectively feeding several yarns is characterized in that each carrier arm is assigned a control mechanism for moving the pressing disc away from the annulus. The control mechanism is advantageously formed by an electromagnet. Between the annulus and the pressing disc there is a step on at least one side for introducing the yarn between the said pair.

The device according to the present invention further makes it possible to feed the yarn by wrapping it around an annulus. The said annulus is provided with a circumferential groove; yarn is guided in the circumferential groove of the pressing disc, a guiding comb being attached to said annulus for spreading the yarn windings around the annulus mounted in front of the gap for the free passage of yarn made between the annulus and the driving rotary body.

The driving rotary body is made of material with a high coefficient of friction and a sufficient resistance to abrasion, e.g., of hard rubber, wood, etc.

The annulus is preferably made, in view of the necessary low moment of inertia, of material of the lightest possible specific mass, e.g., aluminum, duraluminum, nylon, textile material, or any material of similar properties. It is desirable that this material has a maximum coefficient of slip friction with the material of the driving rotary body, in order to eliminate mutual slippage to a maximum extent.

The advantage of the device according to the present invention consists in that the nip line is formed by cylindrical surfaces, and thus the device is not responsive to changes of the point of entrance of the yarn into the nip line. This fact is particularly important when processing yarns in the form of a flat tape.

A further advantage of the device according to the present invention consists in that upon changing the yarn feeding velocity during operation of the machine, the thus fed yarn is not subjected to the effect of additional stressing caused by its rolling along the nip line upon axial displacement by means of yarn guides, as e.g., in the device with two rolling cones. Thus, there occurs no overtension of yarn, which might cause a breakage upon processing yarn of lower strength properties, or glazed yarns in the fabric upon processing silk yarns. I

The device according to the present invention makes possible the simultaneous feeding of several yarns by one feeding device, the selective feeding of several yarns, and the feeding of yarns without the usual gripping upon passing the nip line of the cooperating rotary bodies.

Further advantages of the device according to the present invention are described in the following specification and the diagrammatic drawings illustrating the present invention.

An embodiment in the form of an example of the device according to the present invention is diagrammatically shown in the accompanying drawings, in which:

FIG.1 shows a first embodiment of the device according to the present invention, in perspective view the device being employed in the measuring device of the loom with pneumatic weft insertion;

FIG.2 is a view in perspective on an enlarged scale of the embodiment of the feeding device shown in FIG.1;

FIG.3is a view in perspective of a second embodiment of the device according to the present invention;

F104 is a detail in partial section of an embodiment of the carrier;

FIGS is a detailed view in vertical axial section of another embodiment of the carrier;

FIG.6 is a view in vertical axial section of the arrangement of three rotary bodies;

FIG.7 is a view similar to FlG.6 of another arrangement of three rotary bodies;

FIG.8 is a view in perspective of an embodiment of the device with an alternative arrangement of the support;

FIG.9 is a view in section along the plane IX-IX as shown in FIGS;

FlGJi) is a view partially in side elevation and partially in vertical axial section of an arrangement of the device for feeding two yarns simultaneously;

FIG. is a view similar to FIG.10 of an arrangement of the device for selectively feeding two yarns;

FIG.12 is a view in plan of the arrangement of the device as shown in FlG.ll;

FIG.13 is a view from the side of another arrangement of the device for selectively feeding two yarns;

FIG.14 is a view in vertical section of an arrangement of the device as shown in FIG.13;

FlG.15 is a view in perspective of an arrangement of the device for feeding yarns by wrapping the yarn about the annulus;

FIG.16 is a view in section taken along plane XVI- XVI in F]G.15; and

FlG.l7 is a view in section along plane XVII-XVII in F1616.

ln FlG.l, the feeding device according to the present invention is shown employed on a measuring device of a weaving loom provided with pneumatic weft insertion. The feeding device 1 is mounted between a supply bobbin 2 with a winding or yarn 3, e.g. in the form of a flat tape, and a measuring device 4 constituted by a magazine 5 and a gripping mechanism 6, which is mounted in front of the pneumatic weft inserting nozzle 7 directed into the weft inserting plane. The input part of magazine 5 is made by an injector 8 connected by a tube 9 to a pressure air source (not shown).

The measuring device 4 consists of two jaws 10, 11, of which jaw 11 is controlled by a cam 12, the motion of which is derived, e.g., from the camshaft (not shown) of the loom. The shed of warp yarns is designated by reference number 13, the inserted weft by character 14, the fabric thus formed by 15, and the cutting mechanism by 16. The mechanisms 4 and 16 are currently known and thus not further described.

In FIG.2, the feeding device shown in FIG.1 is illustrated on an enlarged scale. The operative parts of the feeding device 1 are two cooperating nip-forming rotary bodies of which one is constituted by a ring or annulus l7 and the other by a pressing disc 18. Annulus 17 is freely mounted on a rotary driving body 19 in'the form of a trucated cone, which is mounted with its pivots 20, 21 in bearingsv 22, 22' formed in the frame 23 of the device. The frame 23 is mounted on the frame (not shown) of the weaving loom with pneumatic weft insertion. The axis of rotation O of the pressing disc 18 is parallel to the axis of rotation O of the rotary driving body 19.

Annulus 17, made e.g., of aluminum, is provided on one hand with an inner friction surface 24, made with a skewed (generally broad V-shaped) edge (FlGS.6 and 7) for engagement with the outer surface 25 of the driving rotary body 19, and on the other hand by an outer friction surface 25 with which a pressing disc 18 has rolling engagement. Disc 18 is pivotally mounted on a support 27 for the purpose of being moved toward and away from annulus 17.

The rotary driving body 19 has both a minimum and a maximum diameter, of which the latter generally corresponds to the inner diameter of annulus 17. The annulus 17 is rotated by contact of at least a part of its inner friction surface 24 with surface 25 of the rotary driving body 19. Shaft of the rotary driving body 19 has mounted thereon a sprocket 28 which is connected by a chain transmission 29 with a sprocket (not shown) mounted either on the driven cam shaft or another driven shaft of the loom.

Support 27 is constituted in the exemplary embodiment of the device by the support 30, through threaded sleeve or nut 31 on which there passes an adjusting screw 32 mounted in bearings 33, 33', arranged in frame 23 of the device; said screw 32 is provided with a control wheel 34 for manual turning thereof.

The lower part of support 30 is traversably mounted on a guiding rod 35 mounted in frame 23 of the device.

On the holder 30 a carrier arm 37 is mounted by means 6 of a pivot 36, a pressing disc 18 being rotatably' mounted on the pin 38 thereof. On carrier arm 37 there is mounted a yarn guide 39, of which the eyelet is situated near the nip line of the pairof rotary bodies 17,

A coil tension spring 40 acts between support 27 and arm 37 for thrusting the pressing cylinder 18 against annulus 17, said spring 41 being fastened at one of its ends to carrier arm 37 and at its other end in one of openings 42 in holder 30. The pressing force is adjusted by changing the prestress or biasing force of spring 41.

Support 27 is provided with a fork 43, in which the lower part of annulus 17 is fastened. The purpose of fork 43 consists in 'entraining annulus 17 about the driving rotary body Hand in securing it in its adjusted axial operative position.

F163 shows a feeding device of which the ring 17a is arranged axially stationarily and the rotary driving body 19 is axially traversable. A support comparable to support 27 in the first described embodiment is here formed by a bracket 47 on a support plate 48 fastened to a frame (not shown) of the device. In fork 49 of bracket 47 there are mounted gates 50 (of which only one is shown) with traversably guided bearings 51 (of which also only one is shown), pins 52 being mounted in saidbearings (one pin being shown only), said pins mounting the pressing disc 18a. A pressure means 40 for exerting pressure between pressing disc 18 and ring 17 is in the form of-prestressed springs 53 (of which only one is shown) which are mounted in gates 50 and pressed against bearings 51. On bracket 47 .there is mounted a yarn guide 39 for feeding-yarn 3 into the nip line of ring 17a and pressingdisc 18a. The pressing force can be varied by variably prestressing springs 53. The lower part of ring 17 is guided in fork 43, mounted on support plate 48.

The rotary driving body 19, in the form of a truncated cone, is axially traversable on driving shaft 54 mounted in bearings 55, 55' arranged in frame 23 of the device. Driving shaft 54 is splined, being provided with grooves 56, in which there are guided the correspondent projections 58 of hub 57 mounted on the rotary driving body 19.

The axial traverse of the rotary driving body 19 on driving shaft 54 is secured by a control element constituted by a screw 59 provided with a control wheel 60 which is mounted in a bearing 61 arranged in frame 23 of the device. Screw 59 is threadedly connected to an element or entrainer 62 of fork shape, the arms 63 of which engage groove 64 of hub 57.

The lower straight part 65 of entrainer 62 is slidably mounted on the upper surface 66 of a support plate 48, whereby crossing and jamming of arms 63 is prevented in the groove 64. The motion of entrainer 62 caused by turning of screw 59 is indicated by a double arrow 67. The manner of drive of the driving shaft 54 is the same in the embodiment as shown in F162. I

Arms 63 are mounted slidably within groove 64 as shown in lFIG.3 and in modified embodiments in F1084 and 5. As shown in F104, arms 63 are provided at their ends with

rollers

68, 68. It is also advantageous to use a single row ball bearing 69, which is preferred from the viewpoint of the useful life of the said parts (1 10.5). The pressing disc 18 can be guided by ring 17 by pressing disc 18 (1 10.7).

7 The pressing disc (FIGS.2, 3, and 6) which is provided with a cylindrical front surface 70, is guided in the circumferential groove 71 of the annulus or ring. In

FIG.7, the frictionless arrangement is reversed. The ring, provided with a cylindrical front surface 72, is guided in the circumferential groove 73 of the pressing disc.

It is preferred that at least one of the friction surfaces of all rotary bodies be provided with a suitable friction coating, which prevents sliding between the said bodies. In FIG.6 a pressing disc 18 with a friction coating 74 is shown; in FIG.7 there is a ring 17 with a friction coating 74, and in PIC-.5 there is a rotary driving body 19 with a friction coating 74.

The mounting of the ring or annulus in the fork 43 is either slidable (FIGS.2, 3, and 6) .or frictionless (FIG.7). Upon slidable contact it is suitable to provide the operative surfaces of fork 43 with a lining 75 of antifrictional material, e.g. bronze, textile fabric dipped in hot oil, porous materials,etc. The said lining prevents the occurrence of a frictional moment, which at a certain vlaue has a disadvantageous effect upon the starting of the feeding device due to increase of sliding friction between the ring and the driving rotary member 19. Lining 75 may also be arranged on the ring.

It is more advantageous to use a frictionless mounting (FIG.7) which always has a lower friction value than that of sliding friction, particularly when the lubrication is poor. In the frictionless arrangement, fork 43 is provided with a pair of rotatably mounted rollers 76 and 76' of abrasionless'material.

The device as shown in FIG.2 operates as follows:

Upon operation of the loom, the weft inserting shaft drives through the chain transmission 29 of the rotary driving body 19, which entrains ring 17, of which the horizontal adjusted position is secured by being guided in fork 43; such fork and the guiding pressing disc 18 inside circumferential groove 71 of ring 17 retain the ring 17 in vertical position.

Yam 3 guided by guide 39 passes through the nip line between ring 17 and pressing disc 18, the guiding eyelet 39 being mounted near the nip line.

Yam 3 is withdrawn from supply bobbin 2 at a speed which equals the circumferential speed of ring 17, and is sucked in by injector 8 which leads said yarn into magazine 5, in which during the weft picks said yarn end is deposited in loop form. In the interval between two successive picks, yarn 3 is gripped in gripping mechanism 6. Immediately before picking, i.e., before admitting the weft inserting pressure agent into weft inserting nozzle 7, yarn 3 is released bythe upper jaw 11 upon turning cam 12, thus releasing for weft insertion, the yarn supply which is about 85 percent of the whole inserted yarn length. The remaining percent of the weft length is fed directly during weft insertion, i.e., at a time at which jaws 10, 11 are opened, at an average withdrawing speed adjusted by means of control wheel 34.

The weft insertion is finished by again closing jaws 10, 11. The weft measuring is thus dependent upon the accurately adjusted feeding velocity and function of the gripping mechanism 6. After inserting weft yarn 14 into the shed 13, the weft is beaten up by the reed towards the fabric 15 while being simultaneously cut by cutting mechanism 16.

After insertion of the weft supply, which is performed at a considerable speed, the weft yarn is not immediately stopped. The velocity of feeding of the weft does not drop immediately to zero, but drops to the average weft inserting velocity at which weft 14 is being withdrawn by the feeding device 1 from the supply bobbin 2. In that manner, the tension impact in the weft 14 is considerably reduced below what it would be upon stopping the yarn from the maximum weft inserting velocity to zero. This makes it possible, by use of the feeding device of the invention, to weave weft yarns with relatively low strengths. 7

At the same time, the breakage rate of the weft is substantially reduced, whereupon the economy of weaving is increased. A further advantage consists in that it is not necessary to brake the weft in front of feeding device I; thus, no twist accumulation takes place, the twist being continuously withdrawn upon passage of the yarn through the passage between the nip line of ring 17 and pressing disc 18.

A change of the circumferential speed of ring 17 is secured by the appurtenant axial adjustment of support 27 and thus of ring 17 by control wheel 34. Such axial traverse of ring 17 can take place during operation of the machine.

The nip line between ring 17 and pressing disc 18 is constituted in that case by two cylindrical surface lines, the device thus not being sensitive to the variation of the contact. point of yarn into the nip line. This fact is particularly important when processing weft in the form of a flat tape.

The device as shown in FIG.3 operates as follows:

Yarn 3, passing through the nip line of ring 17 and pressing disc 18, is withdrawn from a yarn supply winding (not shown) at a speed equal to the circumferential speed of ring 17. When necessary, the yarn feeding velocity of the device may be changed by adjusting the appurtenant axial position of the rotary driving body 19 relative to stationary ring 17 by means of control wheel 60. The speed control can be performed even during operation of the device.

The advantage of the device shown in F163 over the device shown in F162 consists in that upon variation of the yarn withdrawing speed, no change in the position of the nip line between ring 17 and pressing disc 18 occurs. Yarn 3 is thus fed for further processing from the same point. A partial disadvantage of that embodiment consists in its rather more intricate construction.

In FIGSB and 9 there is shown a feeding device in which the support 27 is constituted by an annular sleeve 77, which is fastened by means of screws 78 to a pressing arm 79 mounted swingably on pivot pin 80 on a stationary support 81 mounted on the frame 23 of the device.

An inner ring 82 of a single row bearing 83 is mounted, e.g. by pressing it into an annular sleeve 77 which embraces but does not contact the rotary driving body 19. Upon the outer ring 84 of said ball bearing 83 there is mounted, e.g. by pressing, a ring 17d which is formed by a straight cylindrical housing 85 which passes over into a radial flange 86, of whichthe inner friction surface 24 is at least in partial frictional engagement with the surface 25 of the rotary driving member 19.

On the annular sleeve 77 there is arranged a pivot 87 on which a support arm 37 is swingably mounted, on a pivot pin 38 of which there is rotatably mounted a pressing disc 18d. The pressing means 40 for exerting pressure between ring 17 and rotary driving cone 19 is a spring 89, secured at one end on support arm 37 and its other end on annular sleeve 77.

Between the stationary support 81 and pressure arm 79 there is mounted a torque spring 90 disposed about the hub of pressing arm 79; the spring tends to turn the pressing arm 79 in the counterclockwise direction (FlG.8).

The pressure between ring 17d and pressing disc 18d is provided by the spring 89. Ring 1711 is thus not pressed towards the rotary driving body 19 by pressing disc 18d, as in the preceding embodiments, but by means of an inner ring 82 of the annular sleeve 77 and the pressing arm 79 of spring 90.

In an exemplary embodiment, rqng 17d is made axially immovable, while the rotary driving body 19 is axially traversable in the direction of the double arrow in FlG.9. The arrangement of support 27 shown in FIGS. 8 and 9 can, with a small obvious modification, be used even for the modification of the withdrawing mechanism with an axially immovable rotary driving body 19 and an axially adjustable ring 17d.

The device as shown in FlGS.8 and 9 operates as follows:

Upon rotation of the rotary driving cone 19, ring 17d is entrained by engagement of its inner frictional surface 34 with the surface of rotary driving body 19, the outer ring of ball bearing 83 rotating on an immovable inner ring 82. Yarn 3, which is directed by a yarn guide (not shown), enters the nip line of the ring 17d and pressing disc 18d. The control of the withdrawing speed is performed by adjusting the axial position of the rotary driving body 19 with respect to the axially immovable ring 17d. 9

The advantageof the said arrangement consists in a more accurate and more reliable guiding of ring 17d particularly. at higher speeds of rotation, which prevents undesirable vibrations which would act unfavorably upon the lifetime of the device. A further advantage consists in the possibility of independently adjusting the pressure of ring 17d against the rotary driving body 19 and the pressing disc 18d towards ring 17d.

It is not necessary to press the yarn 3 passing through the nip line towards the ring 17d with a force necessary for pressing ring 17d on to the rotary driving body 19; said force is usually too high for pressing yarn and thus unfavorably affects the quality of the fed yarn. A smaller disadvantage consists in the more intricate construction and a higher inertia of ring 17d; this has an unfavorable effect upon the starting of the machine.

In FlG.l0, a device is shown for feeding two yarns. The pressing disc 18c is provided with a step 92 which engages the circumferential groove 93 disposed intermediate the width of ring 17a. The nip line between the pressing disc 18:: and ring 17c is divided into two partial nip

lines

95, 95, through which there pass yarns (not shown). it is advantageous to provide one or both frictional contact surfaces of ring 17c and pressing disc 18c with a frictional coating; in F1610, ring 17s is provided with a frictional coating 74.

The device described above is intended for feeding two yarns from two supply bobbins at the same speed. This arrangement can be advantageously employed with weaving machines with hydraulic or pneumatic weft insertion, operating with two measuring devices;

In FIGS.11 and 12, a modification of the embodiment of the feeding mechanism according to the present invention is shown, such device, in contrast to the preceding embodiments, feeding yarns intermittently.

This modification is suitable wherever an accurate yarn length has to be fed at predetermined time intervalsj Collar 92 of pressing disc 19 engages the circumferential groove 93 of ring 17f, said collar dividing the nip line-into two partial nip lines 95, 95'. At both sides of pressing disc 18 there are tapers 96, 96' for introducing

yarns

3, 3 into said partial nip

lines

95, 95. The tapers are formed, e.g., by chamfering at least one frictional contact surface. In FlG.11, the

taper

96,96 is formed by chamfering the side edges of pressing disc 18.

The device is further provided with two swingably mounted yarn guides 39, 39, of which the movement in the direction of double arrow 97, 97'is derived from a known means (not shown), e.g., a cam or other eccentric mechanism. The yarn guides 39, 39' are swingable into both operative and inoperative positions. In the operative position, the yarn guides 39, 39 are mounted in such manner that yarns 3, 3' are directed out of the partial nip lines 95, 95' (FlG.l1). In the op erative position-of yarn guides 39, 39, yarns 3, 3' enter directly between ring 17f and feeding cylinder 18f.

The device as shown in FIGS.11 and 12 operates as follows:

Upon rotation of ring 17f pressing disc 18f rolls thereabout and the

yarns

3, 3 threaded in the yarn guides 39, 39' in their inoperative position are guided to the respective partial nip

lines

95, 95, and thus withdrawn from supplybobbins (not shown) at a speed corresponding to the circumferential speed of ring 17. Upon stopping the feeding of

yarn

3 or 3 the

appurtenant yarn guide

39, 39 returns to its inoperative position and disengages the yarn from the partial nip line 95 or 95'.

It is obvious that the feeding mechanism .can also be arranged for intermittent feeding of one yarn. in that case, a single nip line is formed by contact of ring 17f and pressing disc 18f, and taper 96 is made on that side of the feeding disc 18f at which a movable yarn guide 19 is arranged.

The device as shown in FlGS.13 and 14 is designed for the samepurpose as the device as shown in FlGS.l 1- and 12. The construction of the device as shown in FlGS.13 and 14 differs from the arrangement as shown in FIGSB and 9 by the use of another embodiment of the pressing element. One ring 17g is assigned two pressing discs 18g, 18g which are rotatably mounted on swingably mounted support arms 37, 37' carried by tie rods 99, 98' constituting the armatures of two electromagnets 99 (of which only one is shown), the energizing of which is controlled by a known control mechanism (not shown). The feeding device is arranged behind a yarn brake (not shown). The

support arms

37, 37 are swingably mounted on support 27 by means of elements (not shown).

The device is further provided with two stationary guide yarns 39 (of which only one is shown), by which

yarns

3, 3 are introduced between the partial nip

lines

95, 95. Springs (not shown) act upon support arms 37;

such springs press the pressing discs 18, 18' towards ring 17 when the electromagnets are deenergized. ln FIG.13 there is shown an injector 8 of a measuring device (not shown) of the weaving machine with pneumatic weft insertion.

The device as shown in FIG.13 and 14 operates as follows:

For example, upon energizing the electromagnets 99, their armatures lift tie rods 98 into their upper position, whereupon the pressing disc 18g is moved away from ring 17g, the feeding of yarn 3 being thus interrupted (FIG. 13).

The assumption of a correct function of the device is that the traction exerted on the yarn by injector 8 should not overcome the braking of the yarn by means of a brake (not shown), as thereupon the yarn would be withdrawn in an uncontrolled manner even after lifting pressing disc 18g or 18g, respectively. After deenergizing the electromagnets, a spring (not shown) draws the pressing disc 18g again into contact with ring 17g and thread 3' is again withdrawn.

While the arrangement with swingably mounted yarnguides 39, 39 (FIGSJI and 12) can be applied in all modifications of the feeding device, the embodiment with controllable pressing discs 18g, 18g (FIGS.13 and 14) can be used only in devices with ring 17g mounted on a ball bearing 83 (FIG.9).

The two modifications of construction as shown in FIGS.11, l2 and 13, 14 can be advantageously used for weft change in looms with pneumatic or hydraulic weft insertion. For that purpose, the introducing yarn guides 39, 39 or electromagnets 99 are controlled by a programming device, which controls on one hand the feeding of yarn into the separate magazines of the measuring devices, and on the other hand the withdrawal of the accumulated weft supply by the weft inserting mechanism. The feeding of yarn during weaving with one weft is continuous. Upon weft change, immediately after finishing weft insertion, the feeding of the inserted weft yarn is interrupted and a further weft is fed which is to be inserted into the shed upon the following weft inserting step.

In FIGS.11, l2, l3, and 14, a device is shown for two pick change. Upon multi-pick change, a wider ring or annulus and several pressing discs are used.

In FIGS. 15, 16, and 17 a feeding device is shown, in which the yarn 3 is fed, not by passing through the nip line between the pressing disc 18h and ring 17h, but by being wrapped about said ring 17h.

Ring 17h, which has a form similar to that of the ring shown in FIG.2, is guided within a fork 43 of a support (not shown), said fork being provided with an antifrictional coating 75. The bottom of the circumferential groove 71 is provided with a suitable frictional coating 74, e.g. of rubber, which provides a good adhesion be-' tween ring 17h and yarn 3.

The flanges of ring 17h are guided in circumferential groove 73 of pressing disc 18h. Between the ring 17h and the pressing disc 18h there is a gap 100 for the free passage of yarn 3. On the support arm 37 there is mounted a guiding comb 101.

The arrangement as shown in FIGS.15, l6, and 17, which can operate without the usual yarn guide, can be applied for the feeding device with an axially immovable as well as an axially movable rotary driving body 19. The most suitable application is the embodiment of the feeding device with ring 17 mounted on a ball bearing 83 (FIG.9). In that case, it is necessary to complete this device only by a yarn guide and to eliminate the pressing disc 18h.

Yarn 3, which is wrapped at least once about ring 17h, is fed by rotation of ring 17h, the function of the pressing disc 18 consisting only in constituting the necessary pressure of ring 1711 towards the rotary driving body 19. I

The advantage of the arrangement as shown in FIGS.I5, l6 and 17 consists in that the yarn 3 is not gripped upon feeding, this being advantageous upon weaving textured yarns.

Although the invention is illustrated and described with reference to a plurality of preferred embodiments thereof, it is to be expressly understood that it is in no way limited to the disclosure of such a plurality of preferred embodiments, but is capable of numerous modifications within the scope of the appended claims.

What is claimed is:

l. A device for feeding yarns in textile machines, comprising two rotary bodies which cooperate to form a yarn feeding means, one rotary body comprising a ring provided with an inner frictional surface and an outer frictional surface, a rotary driving body of revolution which has a diameter which increases continuously from a minimum to the maximum diameter, the ring fitting over the rotary driving body and being rotational by contact of at least a part of its inner frictional surface with the surface of the rotary driving body, the other rotary body being at least one pressing disc, the axis of rotation thereof being parallel to the axis of rotation of the rotary driving body, the ring and the rotary driving body constituting a frictional driving pair of members of which at least one member is axially traversable with respect to the other member of said frictional pair, whereby to vary the speed of the yarn fed thereby.

2. A device as claimed in claim 1, wherein the rotary driving body is a truncated cone.

3. A device as claimed in claim 1, comprising a support, means rotatably mounting the pressing disc on the support, the pressing disc being selectively movable away from the ring, and at least one pressing means on said support for urging the pressing disc towards the ring.

4. A device as claimed in claim 3, wherein the support is provided with a fork for axially traversing the ring.

5. A device as claimed in claim 3, comprising at least one yarn guide on the support.

6. A device as claimed in claim 3, comprising a stationary guideway, means mounting the support for adjustment along said guideway, and wherein the driving body is axially stationary, and the guideway is parallel to the axis of the rotary driving body.

7. A device as claimed in claim 3, wherein the support is provided with at least one swingable supporting arm on which the pressing disc is rotatably mounted.

8. A device as claimed in claim 7, wherein the pressing means is constituted by a spring arranged between the supporting arm and its support.

9. A device as claimed in claim 3, wherein the support is provided with a gate, in which there are guided pins on the pressure disc.

10. A device as claimed in claim 9, wherein the pressing means is a spring arranged on a support for acting with force upon pins of the pressing disc.

11. A device as claimed in claim 3, wherein the support comprises an annular sleeve mounted contactlessly on the rotary driving body and fastneed to a pressing arm swingably mounted on a stationary sup port, and the annular sleeve is immovably connected to an inner ring of a ball bearing on which an outer ring of a ball bearing carrying the ring is rotatably mounted.

12. A device as claimed in claim 11, wherein the ring is constituted by a straight cylindrical sleeve housing which passes over into a unilateral radial flange with an inner friction surface engaging the rotary driving body.

13. A device as claimed in claim 11, wherein the pressing arm is spring loaded for securing frictional engagement between the ring and the rotary driving body.

14. Adevice as claimed in claim 1, comprising means mounting the pressing disc in axially immovable position, and means mounting the rotary driving body for adjustment axially with respect to the axially immovable disc.

15. A device as claimed in claim 14, wherein the rotary driving body is traversably mounted on a driving shaft and is movably connected with said shaft on one side, and is connected with a control member for adjusting the position of the rotary driving body on the driving shaft on the other side.

16. A device as claimed in claim 15, wherein the control member is constituted by a screw with an entrained yoke which engages a groove in the hub of the rotary driving body.

17. A device as claimed in claim 1, wherein at least one of the pair of rotary members is provided with a frictional coating.

18. A device as claimed in claim 1, wherein at least one of the pair of rotary bodies is provided with a circumferential groove in which the other body of said pair is guided.

19; A device as claimed in claim 1, wherein one of the pair of rotary bodies has a circumferential groove dividing the nip line into two partial nip lines, said groove being engaged by a radial collar mounted on the other rotary body of said pair, and a pair of independently controllable yarn guides for selectively introducing yarn into either of the partial nip lines.

20. A device as claimed in claim 1, wherein there are at least two pressing discs for each ring.

21. A device as claimed in claim 20, wherein each support arm has a control mechanism for moving the pressing disc away from the ring.

22. A device as claimed in claim 21, wherein the control mechanism is an electromagnet.

23. A device as claimed in claim-20, wherein between the ring and the pressing disc there is arranged at least unilaterally a taper for introducing yarn between the said two rotary bodies.

24. A device as claimed in claim 2, wherein the ring and the presser disc form a yarn feeding nip between them.

25. A device as claimed in claim 1, wherein the yarn is wrapped at least once around the ring, the ring is provided with a circumferential groove, the ring is guided inside a circumferential groove in the pressing disc, and

Claims

1. A device for feeding yarns in textile machines, comprising two rotary bodies which cooperate to form a yarn feeding means, one rotary body comprising a ring provided with an inner frictional surface and an outer frictional surface, a rotary driving body of revolution which has a diameter which increases continuously from a minimum to the maximum diameter, the ring fitting over the rotary driving body and being rotational by contact of at least a part of its inner frictional surface with the surface of the rotary driving body, the other rotary body being at least one pressing disc, the axis of rotaTion thereof being parallel to the axis of rotation of the rotary driving body, the ring and the rotary driving body constituting a frictional driving pair of members of which at least one member is axially traversable with respect to the other member of said frictional pair, whereby to vary the speed of the yarn fed thereby.

11. A device as claimed in claim 3, wherein the support comprises an annular sleeve mounted contactlessly on the rotary driving body and fastneed to a pressing arm swingably mounted on a stationary support, and the annular sleeve is immovably connected to an inner ring of a ball bearing on which an outer ring of a ball bearing carrying the ring is rotatably mounted.

19. A device as claimed in claim 1, wherein one of the pair of rotary bodies has a circumferential groove dividing the nip line into two partial nip lines, said groove being engaged by a radial collar mounted on the other rotary body of said pair, and a pair of independently controllable yarn guides for selectively introducing yarn into either of the partial nip lines.

23. A device as claimed in claim 20, wherein between the ring and the pressing disc there is arranged at least unilaterally a taper for introducing yarn between the said two rotary bodies.

25. A device as claimed in claim 1, wherein the yarn is wrapped at least once around the ring, the ring is provided with a circumferential groove, the ring is guided inside a circumferential groove in the pressing disc, and a guiding comb cooperating with the ring for spreading the wraps of yarn around the ring, the comb being mounted in front of a gap in the ring for the free passage of yarn, mounted between the ring and the rotary driving body.