GB2283762A

GB2283762A - Yarn feeding device for a loom

Info

Publication number: GB2283762A
Application number: GB9323262A
Authority: GB
Inventors: Fabio Botturi
Original assignee: Individual
Current assignee: Individual
Priority date: 1993-11-11
Filing date: 1993-11-11
Publication date: 1995-05-17
Anticipated expiration: 2013-11-11
Also published as: GB9323262D0; GB2283762B

Abstract

A yarn feeding device, for regulating the yarn feed speed in a loom, comprises a T-shaped hollow conveying element (14) in the upper portion (15) of which is provided a conveying passage, eg a suction passage, for yarns and to the vertical portion (16) of which is attached means, such as a piston cylinder unit (17), actuating an obturator member (20) to obstruct the conveying passage and thereby brake the yarns when required during operation of the loom. The cylinder height and consequently the projection of the member (20) is adjustable. The piston cylinder unit may be replaced by an electromagnet controlled by the loom circuit. <IMAGE>

Description

YARN FEEDING DEVICE FOR A LOOM The present invention relates to a yarn feeding device for a loom.

In looms, yarn is unwound from spools and conveyed to the loom for the weaving process. In order to facilitate unwinding of the yarn from the spools, a suction conveying device is provided to suck air from a passage through which the yarn unwinding from the spools pass. As only a suction device is provided for the operation of several looms, when a loop stops the yarn is continuously sucked on and accummulates near the loom. Because of this, the operator is obliged, before starting the loom for a new weaving process, to wind the yarn back onto the spools. This prejudices productivity and thus increases production costs.

Another drawback is that the feed speed of the yarn is always the same, regardless of change in the yarn characteristics or in the operation of the loom. This may lead to reduction in the quality of the product, as when the yarn characteristics and loom operation vary it may be necessary to vary the feed speed of the yarn in order to obtain an optimum weaving result.

It would thus be desirable to overcome the above-described disadvantages, especially by way of a device for regulating conveyance of yarns to enable adaptation of looms independently of a centralised feed system.

According to the present invention there is provided a device for regulating the yarn speed in weaving machines characterised in that it comprises an internally hollow conveying element for said yarns and means adapted to partialise and to plug the cavity of the conveying element in sequence with the operative cycle of said machines, said means being fixed in adjustable manner to the conveying element.

Preferably, said means comprises a pneumatic cylinder provided with a round-ended shank adapted to fit the profile of said cavity, said cylinder being screwed on a cap fixed to the conveying element.

For preference, the conveying element is T-shaped, in the upper portion of which the yarns pass and in the vertical portion of which is positioned the cylinder. The cylinder screwed on the cap can be locked in position by a nut, so that said end of the shank projects into said cavity of the conveying element for pressing said yarns during the operation of a weaving machine, said end of the shank plugging said cavity when the machine stops.

An embodiment of the present invention will now be more particularly described by way of example with reference to the accompanying drawings, in which: Fig. 1 is a schematic perspective view of a device embodying the present invention, applied to a loom; Fig. 2 is a cross-sectional view, to an enlarged scale, of the device; and Fig. 3 is a partial view of the device as a detail of Fig.

1.

Referring now to the drawings, there is shown a weaving installation comprising a loom 10 which receives yarns 10 to be woven. The yarns 11, withdrawn from spools 12 and guided through a thread guider 13, arrive in a suction conveying element 14 by which they are conveyed through suction. The conveying element has a Tshaped form,in the upper portion 15 of which is provided a conveying passage for the yarns 11 and in the vertical portion 16 of which is provided a guide passage receiving an obturator member 20, a piston rod 19 of a piston-cylinder unit and part of the cylinder 17 of the unit. The cylinder 17 is screwed into a cap 18 closing the lower end of the vertical guide passage. The member 20 is attached to the rod 19 and has a rounded end matching the internal profile of the yarn conveying passage.

When the loom 10 stops, or if a specific yarn is not necessary in a particular working cycle, the piston-cylinder unit is actuated, for example pneumatically, to cause the member 20 on the rod 19 to be brought into contact with the upper wall surface 21 of the conveying passage in the upper portion 15 of the conveying element 14. By this operation, the conveying passage is plugged or blocked by the member 20 so that the passage of the yarns 11 and of air is reduced or blocked. In this manner the suction systems of the other looms cannot suck the blocked yarns and as a consequence the spools 12 are not unwound.

If the yarn characteristics are different, in order to regulate the yarn speed from the spools to the loom it is sufficient for the operator to adjust the cylinder 17 by screwing it into or out of the cap 18 and locking it in a desired position by means of a nut 22, so that the member 20 projects as much as necessary into the conveying passage of the upper portion 15 of the conveying element 14. It will be self-evident that the greater the extent of projection of the member 20 into the conveying passage the more the yarns are pressed and the greater the decrease in the yarn speed due to suction.

In the above-described embodiment a pneumatic piston-cylinder unit was employed for regulating the yarn speed, but instead of such a unit an electromagnet or other system may be provided which is controlled by the loom circuit and which can construct the conveying passage and consequently regulate the yarn speed.

Claims

1. A yarn feeding device for at least one loom, comprising conveyinc means with a conveying passage for conveying of yarn therethrough anc conveying control means to constrict or block the passage cross-section in dependence on the operation of the loom or looms, the control means being adjustably mounted on the conveying means.

2. A device as claimed in claim 1, the control means comprising e piston-cylinder unit and an obturator member which is connected to the piston of the unit and shaped for co-operation with the wall of the conveying passage.

3. A device as claimed in claim 2, wherein the cylinder of the unit ia mounted in a cap attached to the conveying means.

4. A device as claimed in claim 2 or 3, wherein the conveying means ha a guide passage communicating with the conveying passage, the obturator member being guided in the guide passage.

5. A device as claimed in claim 4, wherein the guide passage extends downwardly from the conveying passage with respect to an intended mounting orientation of the device.

6. A device as claimed in claim 3 or in claim 4 or claim 5 when appended to claim 3, wherein the cylinder is threadedly mounted in the cap and releasably locked in a selected position by means of a lock nut, the cylinder being adjustable in the cap to allow the member to project into the conveying passage to a selectable extent in the retracted state of the piston of the unit.

7. A yarn, feeding device substantially as hereinbefore described with reference to the accompanying drawings.

8. A loom equipped with a device as claimed in any one of the preceding claims for feeding of yarn thereto.

9. Weaving equipment comprising a plurality of looms and a single device as claimed in one of claims 1 to 7 for feeding yarn to all the looms.