US3776282A

US3776282A - Method of and apparatus for metering and storing weft yarn for intermittent insertion into the shed of shuttleless looms

Info

Publication number: US3776282A
Application number: US00270044A
Authority: US
Inventors: Z Sevcik; J Jankovsky
Original assignee: Individual
Current assignee: Vyzkumny a Vyvojovy Ustav Zavodu Vseobecneho Strojirenstvi
Priority date: 1972-07-10
Filing date: 1972-07-10
Publication date: 1973-12-04
Anticipated expiration: 1990-12-04

Abstract

Method of and apparatus for metering and storing continuously metered weft yarn for intermittent inserting into the shed of a shuttleless loom. In such method the weft yarn metering rate is higher than the winding of the same onto a yarn storage drum, the remaining portion of the metered weft yarn length being stored as a loose loop. The device comprises a storage drum provided with a gripper controlled by a cam disc, a metering drum, a chamber, on the entering side of the chamber there being provided a pressing roller attached to the metering drum, and on the exit side thereof there being provided a device for weft yarn braking.

Description

United States Patent [191 Sevcik et al. Dec. 4, 1973 [54] METHOD OF AND APPARATUS FOR 3,140,633 7/1964 Vincent 139/127 P METERING AND STORING WE YARN 3,575,217 4/1971 Pfarrwaller 139/122 R FOR INTERMITTENT INSERTION INTO THE SHED OF SHUTTLELESS LOOMS Primary Examiner-Henry S. Jaudon Attorney-Arthur O. Klein [57] ABSTRACT Method of and apparatus for metering and storing continuously metered weft yarn for intermittent insening into the shed of a shuttleless loom. In such method the weft yarn metering rate is higher than the winding of the same onto a yarn storage drum, the remaining portion of the metered weft yarn length being stored as a loose loop. The device comprises a storage drum provided with a gripper controlled by a cam disc, a

metering drum, a chamber, on the entering side of the chamber there being provided a pressing roller attached to the metering drum, and on the exit side thereof there being provided a device for weft yam braking.

l6 Claims, 4 Drawing Figures [75] Inventors: Zdenek Sevcik; Josef Jankovsky,

both of Brno, Czechoslovakia [73] Assignee: Vyzkumny a vyvojovy ustav Zavodu vseobecneho strojirenstvi, 11519, Czechoslovakia [22] Filed: July 10, 1972 [21] Appl. No.: 270,044

[52] US. Cl 139/122 R [51] Int. Cl [58] Field of Search; 139/122 R, 122 H, 139/127 P, 125, 126; 66/132 [56] References Cited UNITED STATES PATENTS 2,519,786 8/1950 Paabon 139/127 P J/ J? z METHOD OF AND APPARATUS FOR METERING AND STORING WEFT YARN FOR INTERMITTENT INSERTION INTO THE SHED OF SHUTTLELESS LOOMS This invention relates to a method of and a device for adjustably metering and storing yarn which is continuously metered and intermittently inserted into the shed of shuttleless looms, especially of jet looms.

On shuttleless looms with a jet or a similar pick, it is necessary to meter the required yarn length for each individual pick. For this purpose various devices are used, such devices being placed on the loom near the picking jet.

Up to now the most perfect known way of carrying out the above method consists in the continuous metering of the weft yarn all the time between two consecutive picks, the yarn metered in the time interval between picks being stored in a spiral form on a storing drum. In the moment of the pick, due to the action of the inserting jet, the stock on the drum is first drawn off and the remaining portion of the weft yarn length required is metered before the pick is accomplished.

The device for carrying out the above-described method consists of a rotating storage drum, a pivoted pressing roller being closely fitted to the metering portion of the surface of the drum. Theyam unwound from the bobbin is carried between thefstorage drum surface and the pressing roller, and is wound up onto the threaded portionofthe storage drum, the diameter of which is approximately in accordance with the diameter of the metering portion of the storage drum.

A disadvantage of the described method and thus of the device in question is that afterdrawing off the stock on the drum, which takes place in a short time at a high delivery speed of the inserting jet, a sudden braking of the weft yarn occurs, the speed of which decreases to a metering speed, this being less than the weft insertion rate. This sudden change of the weft insertion rate causes irregularities in the pick, thereby reducing the quality of the fabric.

A method of and a device for yarn metering is also known wherein the weft yarn is continuously metered by a couple of drums and forms a loopdue to its kinetic energy, either in a free space or one limited by means of a limiting screen, a guard board parallel with the plane of the loop, or a chamber. In some cases the metered yarn comes into contact with a stream of air under pressure to insure a more perfect loop formation and at the same time to prevent the torsion of the same, which may occur due to the considerable size of the loop.

A disadvantage of this method and of the device for metering the weft yarn length inaccordance therewith is a high initial resistance or tension of the yarn being taken-up into the shed, this being caused by a relatively great inertial mass of the length of metered yarn. The weft yarn therefore starts slowly, this causing, especially in the case of a yarn of a less strength or in the case of a heavy yarn, partial defibering resulting in an increased rate of breakage. i

In the final phase of the pick, a further disadvantage appears, as well as in the case of the storage drum, in the sudden braking of the weft yarn decreasing the metering speed of the metering drum, the metering speed being less than the weft insertion rate.

A further disadvantage of this device, especially when metering a greater weft length, e.g.; for modern jet looms, there are required relatively large dimensioned magazines for storing the loop.

A disadvantage of both of the above known devices is the short service life of the metering drum, where either wearing or permanent deformation of the drum is caused by thelmetered yarn, this becoming evident in the reduced accuracy of the length of the metered weft yarn. A further disadvantage of both of such devices is a considerable difficulty in changing the length of the metered yarn.

All the above-described disadvantages and. drawbacks are eliminated by the method of metering and storing the yarn according to the present invention wherein the metering of the weft yarn metering rate is higher thanthe rate of winding of the same onto the storage drum, the remaining portion of the metered weft yarn length being stored as a loose loop.

All disadvantages and drawbacks described in connection with the known devices are eliminated by the device according to the invention, which comprises a pivoted storage drum provided with a swinging gripper controlled by a cam disc pivoted and mounted coaxially of the storage drum, this being provided with a pul-. ley by means of which the same is connected with the adjustable pulley of the metering drum. The diameter of the storage drum is larger than the diameter of the adjustable pulley. In the plane of rotation of the meter ing drum there are arranged two guide plates defining a chamber, on the entering side of which a pressing roller is attached to the metering drum, and on the exit side of the drum there is provided a device for braking the weft yarn. A distributing disc with a curved groove is pivotably adjoined to the pressing roller.

In accordance with a preferred embodiment of the invention, weft yarn braking device includes a cylindrical member which is pivotally and adjustably mounted, an adjustable braking element being attached to such member.

The adjustable'pulley preferably consists of jaws adjustably attached by means of screws to the disc ofthe metering drum. i

A considerable advantage of the method according to the invention consists in an easy and fast-starting of the metered weft yarn movement at the beginning of the pick when a small inertial mass of the continuously rapidly unwound weft yarn from the storage drum acts on the draw-off force into the she-d. Thus, the weft yarn remains qualitatively unchanged, the breakage rate of the same being low. In the final phase of the pick, after drawing off the yarn stock from the storage drum, the yarn stock of the loop is used via the braking elements. This passage is absolutely continuous without any disadvantageous effect on the proper weft insertion.

By action of the braking elements there occurs a gradual decrease of the weft delivery speed from the loop to the metering rate; thus the weft in this phase is inserted continuously, thereby advantageously affecting the fabric quality.

The device for carrying out the method according to the invention has all the advantages described.

A further advantage of this device consists in its relatively small dimensions even when it is used on looms of greater widths.

Another advantage of the device is a substantially longer life of the metering drum, the wear of which is considerably reduced. This fact becomes evident in the permanent metering of the same lengths of weft yarn. A further advantage of the deviceaccording to the invention is an easy change of the rate of yarn metering, such change being made in the portion of the me tered weft length which is stored in a loose loop.

The method of metering and storing of the continu ous metered weft yarn is evident from the following example:

The weft yarn is metered at a rate which is time dependent and which depends further on the required weft length in such a manner that in the time between two consccutive'wcft insertions the required weft yarn length is metered. The metering rate is, at the same time, higher than the rate at which the metered weft yarn is stored on the storage drum. The excess length portion of the metered weft yarn therefore forms a loose loop as a supply stock for the final phase of weft yarn insertion.

An exemplary embodiment of the device according to the invention is illustrated in the drawings:

FIG. 1 is a diagrammatic section of the device viewed from in front;

FIG. 2 is a view in side elevation of the device;

FIG. 3 is a sectional view of the pressing roller and of the yarn distributing disc; and i FIG. 4 is a view in perspective of a jet loom to which the apparatus of the invention may advantageously be applied.

To a housing 1 which is an integralpart of the loom, a flange 2 is attached, e.g., by means of screws (not shown). Between the housing 1 and the flange 2 there is fixed a supporting plate 3. In the housing 1 there is a bearing 4, in which the shaft 5 provided with a gear wheel 6 is journalled. The shaft 5 is further journalled in a eoaxially arranged hollow shaft 7, this being journalled in the flange 2 and inside of the housing 1 being provided with a gear wheel 8. Both gear wheels, the gear wheel 6 and the gear wheel 8 are, via other unillustrated gears, connected with the main shaft of the loom in such a manner that the shaft 5 turns through one more or one less revolution than the hollow shaft 7 in each cycle of the loom.

On the hollow shaft 7 outside the housing 1 there'is afflxed a storage drum 10 by means of a nut 9, the surface of the drum being divided into two parts.'One part 11, placed nearer to the flange 2, has the shape of a pulley, while the other part is provided with shallow grooves 12 arranged in a helix. To the web or disc 13 of the storage drum 10 there is afflxed a pin by means of a nut 14; on the pin 15 there is swingably mounted a gripper 16 in the shape of a double-arm lever, one arm 17 of which is provided on its outer end with a trapping claw 18 and the opposite arm 19 with the roller 20 on its outer end. At the point where the path of the end of arm 17 intersects the trapping claw 18 the storage drum 10, the same is provided with an aperture 21 for the intermittent projecting of the trapping claw 18 over the surface of the storage drum 10. The roller 20 attached to the other arm 19 engages a groove 22 formed in a cam disc 23, which is fixed on the end of shaft 5 and is locked by a nut 24. The cam disc 23 is placed in the hollow 25 of the storage drum 10. The storage drum 10 is partially covered with a cylindrical collar 26 affixed to the flange 2. A guard 28 covering and partially exceeding in axial length the remaining portion of the storage drum 10 is afflxed to the collar 26 by means of, e.g., a bayonet catch 27. The guard 28 is, at the point of the path of the trapping claw 18 of the gripper 16, provided with a circular groove 29, and at the point opposite to the shallow helical groove 12, is provided with a slot 30 for'the feeding of the weft yarn 31. To the outer surface of the guard 28 there is attached a screw 32, on which a bracket 33 with an eyelet 34, placed opposite to the shaft 5 and coaxial of drum 10, is mounted. The bracket 33 is locked in a preset position by means of a nut 35.

The supporting plate 3 is provided with a recess 36, in which another plate 38 is adjustably mounted by a projection 37 thereon which is joined with the supporting plate 3 by a stepped pin 39 and a nut 40 with a washer 41. On the stepped pin 39 there is pivoted a boss 42 with a triangularly shaped flange 43 to which the web or disc 45 of a metering drum is fixed by means of three screws 44. On the opposite side of the metering drum 46 there are adjustably attached six arcuate jaws 47 by means of screws 48 and nuts 49, the attaching means for the jaws 47 passing in the disc 45 through six symmetrically and radially arranged slots 50. The system of jaws 47 forms a pulley 51 of adjustable diameter, the diameter of pulley 51 being always less than the diameter of the metering drum 46. The pulley 51 is connected with the pulley 11, mounted on the storage drum 10, by means of a belt 52, passing through apertures (not shown) in the cylindrical collar 26 of the flange 2.

Above the metering drum 46 a supporting pin 53 is anchored in the plate 38 by a nut 54. On the stepped portion 55 of the pin there are fitted a holder 56 and two guide plates 57 and 58. The surfaces of the guide plates 57 and 58 which face each other define a cham ber 59, the plates being spaced on the portion 55 of the supporting pin 53 by a spacing ring 60 inserted between them. All parts fitted on the stepped portion 55 are tightened by a nut 61.

On the holder 56, as shown in FIGS. 1 and 2, there is adjustably pivoted a cylindrical braking element 62. Around a portion of its circumference in the holder 56 there is provided an arcuate slot 63 in which by means of a screw (not shown) an adjustable braking element 64 with projections 65 for guiding weft'yar'n 31 is adjustably fixed. Both

braking elements

62 and 64 are placed on the'side of the delivery of weft yarn 31 from the chamber 59.

On the side of the feeding of the weft yarn 31 into the chamber 59, there is attached a distributing pin 67 to the plate 38 by means of the nut 66, as shown in FIG. 3. A distributing roller 68 is journalled on pin 67, the surface of roller 68 being provided with an annular groove 69 of curved section. On the distributing pin 67 there is swingably mounted a boss 70 with an arm 71 to which the pin 73 is fixed by means of a nut 72. On the pin 73 there is freely journalled a pressing roller 74 with an elastic covering band 75 for engaging with the metering drum 46, as shown in FIG. 2. The pressing rolmeans of unillustrated gears in the housing 1 and, simultaneously in the same direction, the gear wheel 8 in such a manner'that the revolutions of thegear wheel 6 are by one revolution higher or lower than the revolutions of the gear wheel 8 in each cycle of the loomQThe shaft 5 and the cam disc 23 rotate in accordance with the rotation of the gear wheel 6. The hollow shaft 7 and the storage drum 10 rotate in accordance with the rotation of the gear wheel 8. Due to the different number of revolutions of

gears

6 and 8, the cam disc 23 overruns the storing drum 10 or vice versa; there is thus caused a periodical swinging motion of the gripper 16 carried by the storage drum 10, this being a consequence of the asymmetric position of the groove 22 in the cam disc 23, engaged by the roller 20 of the gripper 16. Due to the swinging motion of the gripper '16, the trapping claw 18 of the gripper l6 alternately hides or protrudes over the surface of the storage drum 10. The rotary motion of the storage drum 10 is transmitted to the adjustable pulley 51 by the belt 52 and simultaneously to the metering drum 46, joined with the same. The metering drum 46 by friction sets the pressing roller 74 into rotary motion, the rotary motion being transmitted by means of the pulley 76 and the belt 77 to the distributing disc 68 withthe curved groove 69.

As can be seen in FIG. 2, the weft yarn 31 passes from a supply bobbin (not shown) through the eyelet 81 and the yarn brake 80, from which the yarn is guided to the distributing disc 68, in which the weft yarn engages a portion of length of the curved groove 69. From here it passes between the metering drum 46 and the pressing roller 74 to the chamber 59, and from the chamber between the adjustable braking element 64 and the cylindrical braking element 62 to the slot 30 in the guard 28, thence to the surface of the storage drum 10 and from it through the eyelet 34 to a picking mechanism, e.g., to the jet of the loom.

After completing the insertion of weft yarn 31, the cam disc 23, due to its continuous rotary motion, assumes a position in which the gripper l6 swings due to the asymmetry ofthe groove 22 in the cam disc 23 and the trapping claw 18 of the same protrudes over the surface of the storage drum l0. ln its continuous rotary motion with the storage drum 10, the trapping claw 18 traps the weft yarn 31, which is held in its path by the slot 30 and the eyelet 34. The weft yarn 31 trapped in this way starts taking up into the shallow helical groove 12 on the surface of the storage drum 10. The taken-up weft yarn 31 is taken off via the cylindrical braking element 62 and the adjustable braking element 64 from the stock of the weft yarn 31 in the loop shape located in the chamber 59 between the guide plates 57 and 58. The stock in loop shape is continuously replenished with weft yarn by the metering drum 46 and the pressing roller 74. Between the metering drum 46 and the pressing roller 74 the weft yarn 31 is led by the distributing disc 68, the curved groove 69 of which, due to ro- In view of the fact that the diameter of the metering drum 47 is always larger than the diameter of the adjustable pulley 51 joined by means of the belt 52 with the storage drum 10, the metering speed of the weft yarn is higher than the winding speed of the same on the storage drum 10, so the portion of the metered weft yarn 31 not taken up rapidly thrust upwardly against the action of gravity to form an enlarging loop L in the chamber 59.

At the moment of starting of weft insertion 31 into the loom, the cam disc 23 assumes a position in which the gripper 16 swings out due to the asymmetry of the groove 22 in such a manner that its trapping claw 18 clips under the surface of the storage drum 10, thus enabling the weft yarn 31 to be continuously, thread by thread, withdrawn from the surface of the storage drum 10 by the action of the drawing-ofi force of the picking mechanism. After drawing off this stock, further weft yarn 31 is drawn-off from the loop in the chamber 59 tation of the distributing disc 68, continuously alterby the picking mechanism over the

braking elements

62 and 64, the loop diminishing in size in spite of its being continuously replenished-by the metering drum 46. The reason is that the delivery speed of theweft yarn 31 is several times higher than the metering rate. At the moment of completing the insertion of the weft yarn 31, the stocking loop is fully spent and the gripper 16 with its trapping claw 18 again traps the weft yarn 31, which starts winding-up onto the storage drum 10.

The whole cycle described above is regularly repeated during the weaving process.

By changing the diameter of the adjustable pulley 51 it is possible to change the metering rate of the weft yarn 31 when it is necessary to change the weft yarn length 31 metered in an interval of one operation cycle. This change of diameter can be achieved by moving the jaws 47 by hand after a preyious loosening of the nuts 49.

By moving the adjustable braking element 64 in the slot 63 it is possible to change the intensity of braking effect of both

braking elements

62 and 64 by changing the amount of their embracement of the yarn. By changing the intensity of the braking effect, the amount of the course of withdrawal from the stock loop up to its full drawing off can be changed, when the weft yarn 31 partially encircles the spacing ring 60 and the remaining length of the weft yarn 31 required for the pick is drawn-off from the metering drum 46.

The invention can be applied to all types of weaving looms on which a metered length of weft yarn is inserted by the picking mechanism, e.g., by a jet, and where continuous uniform feed of an exactly metered length is required.

In FIG. 4 there is shown the illustrative embodiment of weft metering device of the invention applied to a conventional jet loom. Weft yarn 31 from alternative weft yarn supplies 85, passes to the weft metering device and thence to the jet nozzle 86 of the loom. The jet sequentially pulls weft yarn from the weft yarn supply through the weft metering device and inserts it into the shed in a warp 87 which travels from a warp beam (not shown) over a back rest 89. After each weft insertion the reeds 90 beat up the weft. The resulting cloth 91 is pulled forwardly by a draw beam 92, and is wound upon a cloth beam 94.

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

What is claimed is:

l. A method of handling weft yarn for insertion in successive picks into a shuttleless loom, comprising continuously metering the yarn and feeding it forward into a loose loop, withdrawing the yarn from the loop and winding it on a storage drum at a rate less than that of the metering of the yarn, and intermittently withdrawing the yarn from the storage drum and inserting it in a pick into the shed of the loom. v

2. A method according to claim 1, wherein the yarn is retarded in the zone thereof between the loop and the storage drum.

3. A method according to claim 2, wherein in each pick the yarn is first withdrawn from the storage drum, and thereafter, in the final phase of the pick, the yarn is withdrawn from the loop under the retardation thereof imposed thereupon in said zone.

4. A method according to claim 1, wherein the metering and feeding of the yarn into the loop takes place at constant speed.

5. A method according to claim 1, wherein the yarn is gripped to wind it upon the storage drum between successive picks, and the gripping of the yarn on the storage drum is released at the beginning of each pick.

6. Apparatus for handling weft yarn for insertion in successive picks into a shuttleless loom, comprising means for continuously metering the yarn and feeding it forward into a loose loop, a storage drum, means for withdrawing the yarn from the loop and winding it on the storage drum at a rate less than that of the metering of the yarn, and means for intermittently withdrawing the yarn from the storage drum and inserting it in a pick into the shed of the loom.

7. Apparatus according to claim 6, comprising means for retarding the yarn in the zone thereof between the loop and the storage drum.

8. Apparatus according to claim 7, wherein the means for intermittently withdrawing the yarn in each pick first withdraws it from the storage drum and thereafter, in the final phase of the pick withdraws the yarn from the loop under the retardation imposed thereupon in said zone.

9. Apparatus according to claim 6, wherein the means for metering and feeding the yarn into the loop is driven at constant speed.

10. Apparatus according to claim 6, comprising means for gripping the yarn to wind it upon the storage drum between successive picks and for releasing such gripping of the yarn on storage drum at the beginning of each pick.

11. Apparatus according to claim 10, wherein the storage drum is rotatably driven, and the means to grip and release the yarn comprises a selectively radially outwardly advanceable and inwardly retractable finger on the drum, the finger when outwardly advanced forming a bight in the yarn passing around the storage drum.

12. Apparatus according to claim 6, wherein the storage drum is provided with a swinging yarn gripper controlled by a rotatable cam disc mounted coaxially of the storage drum, the drum being provided with a pulley by means of which the same is connected with an adjustable pulley driving a metering drum, the diameter of the pulley on the drum being larger than the diameter of the adjustable pulley.

13. Apparatus according to claim 12, comprising two guide plates arranged to define a loop-containing chamber, on the entering side of the chamber there being a pressing roller attached to the metering drum, and on the exit side thereof there being a device for weft yarn braking.

14. Apparatus according to claim 12, comprising a distributing disc with a curved yarn-receiving groove joumalled adjacent the pressing roller in advance thereof.

15. Apparatus according to claim 12, wherein the means for retarding the weft yarn comprises an adjustably mounted rotatable cylindrical braking roller and a braking element adjustably mounted with respect thereto so that the yarn passes between the roller and the element.

16. Apparatus according to claim 12, wherein the adjustable pulley comprises radially adjustable jaws attached to a disc secured to the metering drum.

Claims

1. A method of handling weft yarn for insertion in successive picks into a shuttleless loom, comprising continuously metering the yarn and feeding it forward into a loose loop, withdrawing the yarn from the loop and winding it on a storage drum at a rate less than that of the metering of the yarn, and intermittently withdrawing the yarn from the storage drum and inserting it in a pick into the shed of the loom.

14. Apparatus according to claim 12, comprising a distributing disc with a curved yarn-receiving groove journalled adjacent the pressing roller in advance thereof.