US3718270A

US3718270A - Devices for picking-up, sucking and dragging textile filaments and yarns

Info

Publication number: US3718270A
Application number: US00093972A
Authority: US
Inventors: Alo B D; P Parmeggiani; D Nicita
Original assignee: SNIA Viscosa SpA
Current assignee: SNIA Viscosa SpA
Priority date: 1969-12-04
Filing date: 1970-12-01
Publication date: 1973-02-27
Anticipated expiration: 1990-02-27
Also published as: IE34787L; ES386165A1; FR2072829A5; IE34787B1; DE2059199A1; NL7001048A; BE759801A

Abstract

A device for pneumatically sucking and dragging the cut ends of textile filaments and yarns traveling at high speeds includes a passage wherein filaments or yarns travel in front of a suction orifice and a related removal duct to which a subatmospheric pressure is imparted. On the other side of the passage and coaxial with the orifice a nozzle is provided to form a superatmospheric pressure air stream incident to the filaments or yarns in cooperation with the suction orifice.

Description

United States Patent [191 Parmeggiani et al.

[ 51 Feb. 27, 1973 [54] DEVICES FOR PICKING-UP, SUCKING AND DRAGGING TEXTILE FILAMENTS AND YARNS [75] Inventors: Paolo Parmeggiani; Domenico Nicita; Bruno D'Alo, Milan, Italy [73] Assignee: Snla Vlscosa SocietaNazionale Industria Applicazioni Viscosa, Milan, Italy [22] Filed: Dec. 1, 1970 [21] Appl. No; 93,972

[30] Foreign Application Priority Data Dec. 4, 1969 Italy ..25357 A/69 [52] US. Cl ..226/97, 57/34.5 [51] Int. Cl. ..B65h 17/32 [58] Field of Search ..226/91, 97, 7; 57/345 [56] References Cited UNITED STATES PATENTS 2,661,588 12/1953 Griset ..226/97 X 3,423,000 1/1969 Heinen ..226/97 3,452,910 7/1969 Richter ..226/97 X Primary Examiner-Richard A. Schacher Attorney-Wenderoth, Lind & Ponack [5 7] ABSTRACT A device for pneumatically sucking and dragging the cut ends of textile filaments and yarns traveling at high speeds includes a passage wherein filaments or yarns travel in front of a suction orifice and a related a removal duct to which a subatmospheric pressure is imparted. On the other side of the passage and coaxial with the orifice a nozzle is provided to form a superatmospheric pressure air stream incident to the filaments or yarns in cooperation with the suction orifice.

2 Claims, 5 Drawing Figures PATENTEI] FEB 2 71973 11111111... TL'D/ ELJ PAOLO PARMEGGIANI,

DOMENICO NICITA and BRUNO D 'ALO' INVENTOR s dwm/m Attorneys DEVICES FOR PICKlNG-UP, SUCKING AND DRAGGING TEXTILE FILAMENTS AND YARNS BACKGROUND This invention relates to improvements in and to mechanisms or devices usually called aspirators and utilized in spinning and more particularly in picking-up and winding operations on textile filaments and yarns. The devices are associated with winding frames or similar winding equipments for taking-up and removing filament and yarn ends otto be taken away during different doffing and throwing operations of the filaments and yarns on taking-up and winding equipment. Obviously, the improvements of this invention may be applied when substantially equivalent operating conditions exist in any other filed of processing and winding filaments and yarns.

This invention also relates to devices which are carried-out and operate according to such improvements and for the stated or equivalent applications and comprising the features as specified below.

Such suction devices and their operations and uses are well known in the art and therefore no particular explanation or comment should be required. Such already known devices basically comprise a body conveniently located and directed in respect of filament or yarn path and having an orifice or hole with an inner diameter of a few millimeters and wherein a vacuum is produced and maintained (when the device is to be operated) by means of a system essentially in the form of a Venturi tube, to which compressed air is fed in order to create downstream thereof an air flow which is fed through a duct for dragging and drawing away the filaments or yarns.

Such device is utilized to take-up yarns that are continuously fed by production and/or processing equipment (stretching equipment or the like), at the end of each winding step thereof (in particular when a bobbin or spool is completely wound-up) and during related doffing operations as well as subsequent throwing operations, e.g. at the start of a next winding step. Obviously such devices may be used every time one or more filaments or yarns are to be picked-up, deflected and removed for temporarily interrupting their regular travel along a given path. In order to perform such picking-up operation, the filaments or yarns are led in front of the orifice and diametrically thereto. Then the filaments or yarns are cut downstream of the orifice (in the travel direction thereof) and the yarn trailing end is picked-up and drawn away through a suction and removal duct.

Notwithstanding all improvements in the art, these known aspirator devices show given operational limits, particularly in the production of artificial or synthetic filaments or yarns at relatively high speeds. In particular, such devices can reliably operate only when the yarns travel at speeds in the order of some hundred meters per minute, or at the speeds usually maintained in conventional synthetic yarn producing techniques. In order to ensure a satisfactory operation of the device at even slightly higher speeds or at speeds of about one thousand meters per minute, given critical conditions and requirements must be met. Thus, the yarns are to be perfectly led to suction orifice and they must be cut at pre-established distances from such orifice, since otherwise the picking-up action would be insufficient or no sucking of the yarn end into the hole would occur. Irregular or missed operations of already known devices can occur due to many reasons, as e.g. the inertia of yarns traveling at high speeds, the elastic shrinkage thereof subsequent to their cutting, and the like.

The actual technique in producing textile fibers and in particular but not exclusively synthetic fibers, aims to attain a strong increase in the linear speed of such yarns or filaments, such speeds being always higher than at least 500 meters/minute up to many thousands of meters/minute. Equipment and plants were successfully tested wherein the yarns were taken-up at speeds of the order of 4,000 ormore meters/minute. At such speeds the operational reliability of the already known devices is reduced or even null.

SUMMARY Accordingly, an object of this invention is to recognize the technical requirements to be met when working with yarns traveling at high and very high speeds, of the order of many thousands e.g. of 5,000 meters/minute, to solve the technical problems arising from such recognition and to provide improved devices on the basis of such solved'problems.

Thus, a more specific object of this invention is to provide improved devices adapted to reliably pick-up and draw away filaments or yarns even of very fine counts and traveling at speeds of the'order of thousands of meters/minute.

It is to be noted that well known terms such as sucking and vacuum picking-up" refer in practice to the effect of a gradient between a subatmospheric pressure within a duct deriving from a so called suction orifice and the atmospheric pressure outside such orifice. Such pressure gradient between the orifice inside and outside, i.e. the absolute value of the difference between these pressures, results in air air stream from the outside into said orifice and adjacent duct, due to the outer atmospheric pressure which is not balanced by the inner subatmospheric pressure. Even assuming that a Venturi tube system (or anyother vacuum producing means) could succed in wholly reducing the inner pressure, then the pressure gradient would not exceed the value of the atmospheric pressure (about 1 kg/sq.cm.). Therefore, the resulting air stream speed would never exceed the theoretical speed of an air stream that flows across an orifice in a wall subjected to atmospheric pressure on one side and to an absolute vacuum on the other side. Obviously, such theoretical conditions cannot be attained in practice.

Therefore, a picking-up or dragging operation of yarns into the suction orifice and downstream thereof cannot occur with a force exceeding that resulting from the dynamic and viscosity effects to which the yarns (having a very small section) are subjected into an air stream having a speed not exceeding the upper limit. In such dragging operation will take place at a speed much lower than that of the air flowing into the suction orifice. It has been ascertained that such speed (and .even the speed which is theoretically attainable) as well as the resulting dynamic effects thereof, are insufficient to obtain a required practically instantaneous and strong picking-up operation that is essential for drawing away the cut ends of yarns traveling at very high speeds used in most modern plants. ln fact, when working on yarns traveling at high and very high speeds, the dragging operation shall occur at corresponding speeds.

According to a basic feature of this invention, a device is provided wherein the yarns, which travel at a very high speed in front of the suction orifice thereof, are subjected to the action of an air stream flowing at a very high linear speed caused by a pressure gradient higher than the value of atmospheric pressure, the yarns being then forced into the suction orifice. According to another feature of this invention, the im proved device comprises a nozzle by which a high speed air jet is directed toward the suction orifice and which is coaxial therewith, in order to intercept the yarns traveling in front thereof.

The subatmospheric pressure downstream of the orifice is preferably but not necessarily obtained by means of a Venturi tube system or other equivalent device to which highly pressurized air is fed in order to ensure that an air stream is maintained in the yarn removal duct at a speed much higher than that of the traveling yarns for ensuring the continuation of the dragging operation without any clogging and obstruction.

Moreover the device preferably comprises a partly enclosed portion wherein the yarns are brought and guided in front of the suction orifice, and wherein the air stream acts on the same. More detailedly, the device comprises a channel essentially perpendicular to the axis of a nozzle which in turn is connected to a compressed air source, the nozzle forming a high speed air jet originating means in a direction co-axial with the suction orifice and with the passage or the duct downstream thereof. The channel is opened preferably by means of a longitudinal slot through which the high speed traveling yarns may be introduced and positioned within the channel in such a manner as to be under the action of the dynamic pressure exerted by the air jet aiming to move the same toward and into the suction orifice.

The device can be obviously carried-out in the form of a structural unit comprising two or more means and systems as previously described, for'double winding frames and/or a plurality of winding frames.

DRAWINGS FIG. 1 is a longitudinal section of a device according to this invention, taken along the line 1-1 of FIG. 2.

FIG. 2 is a cross-section, taken on the line [1-11 of FIG. 1, on the same device.

FIGS. 3 and 4 are further cross-sections taken on the lines III-III and IV-IV respectively of FIG. 1.

FIG. 5 is a diagrammatic view on a larger scale of a more characteristic portion of the device shown in FIG. 1, in order to outline the operation thereof and the physical phenomena wherefrom such operation depends.

PREFERRED EMBODIMENT As shown in FIGS. 1 to 4 of the'drawings, the device comprises a structural body preferably but not necessarily consisting of two components and 12, the latter being fitted on top of the former and connected thereto by suitable means (screws, bolts and the like) not shown, as well/as of a third essentially tubular component 14, such components forming together a device The path followed by the yarn to be submitted to action of the device during doffing and throwing opera-1 tions of a winder or winding frame is shown by the segment BB in FIGS. 2 and 3, and also indicated with B in the sections of FIGS. 1 and 5. The yarns are forced to follow this path due to a narrow channel 24, comprising a slot 26 open to the atmosphere for the introduction of the yarns and positioned within the plane of the channel axis in order to facilitate the introduction of yarns traveling at very high speeds.

Perpendicularly to the axis of the narrow channel 24 and to the plane of the slot 26 (which is preferably defined by the structure of the mutually engaging components l0 and 12) a passage 28 is formed within the component 14 and coaxial to duct 22, in order to remove the ends of cut yarns through the same. A nozzle 30 is co-axially positioned with reference to the passage. The outlet of the passage 28 defines a suction orifice wherein the yarn ends are sucked and led into the removal duct 22. The yarns are diagrammatically shown at F in FIG. 5, at the beginning of the picking-up action thereon.

A suitable subatmospheric pressure is formed and maintained, by already known means, within the passage 28, the outlet end of which preferably opens into a larger passage 32 in the pipe fitting 20. All around the passage outlet end a plurality of crown arranged narrow passages 34 have their outlets, such passages deriving form an annular chamber 36 wherein high pressure air is fed, e.g. with a pressure in the range of 10 to 35 kg/sq.cm.

Preferably, both the chamber 36 and nozzle 30 are fed with compressed air coming from the pipe fitting 16 which is connected to a passage 38 having a branched duct 40 that leads into chamber 36 and an extension duct 42 by which the air is fed to nozzle 30 through a crosswise directed passage 44. An air jet comes therefore from nozzle 30 in a direction crosswise to the path B-B of the yarns, which are thus forced toward and into the suction orifice and passage 28.

From the above discussed and from the accompanying drawings it is obvious that the yarns, traveling along the pats B--B, undergo. to a combined action of the vacuum maintained in passage 28 and respectively of the dynamic thrust exerted by the air jet coming from nozzle 30, having a speed depending on the pressure gradient between the upand downstream sides of the nozzle opening into channel 24.

It is obvious that, since no theoretical limit is set for the air pressure fed to nozzle 30, the speed of the air jet coming therefrom may be selected theoretically at will, and an air speed always higher than the yarn traveling speed can be easily and practically attained. Therefore, both a very strong thrust to deflect the yarn ends toward the inlet of passage 28, and a very quick inbe obchannel 24 due to the air jet of nozzle 30. Therefore the air jet must be co-axial with said passage 28 and have a crosssection such as to prevent any interference with the walls of the suction orifice. Further the air stream flow must meet two opposed requirements, namely to ensure the necessary dynamic thrust action on the yarns at the point B, and to maintain a substantial vacuum in passage 28 at the orifice 26, in order to prevent any disturbance in the correct position of the yarns along the path B-B.

Accordingly, the free section of nozzle 30 must be smaller than that of passage 28. The ratio of the inner diameters of nozzle 30 and respectively of passage 28 shall be preferably in the range of one-sixth to one-half when operating with equal pressures in chamber 36 and feed passage 44.

Obviously, the device is dimensioned accordingly to the total count of yarns traveling at high speeds therein and which are to be picked-up and led into the removal duct. Practical experiments have proven the high efficiency and absolute reliability of a device as shown in FIGS. 1 to 4 when operating on synthetic yarns having a count of deniers to 5,000 deniers, said device including a nozzle 30 with a diameter of 1 mm, a suction passage 28 having a diameter of 3 mm, and a channel 24 having a diameter of 3.2 mm and in communication with the outside through a slot-shaped passage 26 having a thickness of 2.5 mm.

The yarn picking-up and pulling force into and beyond the suction orifice will obviously depend on the air pressure fed to the device. For instance, with a device dimensioned as stated above, an absolute operational regularity and reliability, greatly independent from the distance between the device and the cutting points of yarns traveling at high speeds, up to 4,000 m/min., were obtained by feeding air at a pressure of 25 kg/sq.cm.

It is to be understood that the above disclosed device represents a preferred embodiment only, to which many changes and modifications may be made without departing from the spirit and scope of this invention. Thus, e.g. inlet passage 26 could be V-shaped or have a flared inlet end, to make easier the yarn introduction. Means for adjusting the cross section of

passages

40 and 42 respectively leading to subatmospheric pressure generating means 34 and said to said air jet producing nozzle for picking-up and dynamically deflecting the yarns may be provided in order to allow the ratio and absolute values of respective air feeding flows to be modified. If required, these means may be connected to different com pressed air sources.

Moreover, multiple devices may be provided wherein two or more operating systems as diagrammatically shown in FIG. 5 or equivalent thereto, may be associated in a single structural assembly and fed by means of a single pipe fitting connected to a compressed air source, such single pipe fitting comprising different passages (such as

passages

40, 42 and 44) parallely branched therefrom for feeding different nozzles and related vacuum picking-up means.

We claim:

1. A device for sucking and dragging the ends of textile filaments and yarns which are cut during movement at speeds of at least 1,000 meters/minute thereof to collecting and winding equipment, said device comprising a filament or yarn removal duct having a suction orifice at one end thereof; pressure means spaced from said suction orifice to create a subatmospheric pressure condition at said suction orifice; means guiding said filament or yarn in a direction substantially perpendicular to the axis of said suction orifice and adjacent thereto; a passage having a circular cross-section surrounding said filament or yarn and communicating with said suction orifice; a nozzle having a cross-section smaller than that of said suction orifice and coaxially aligned therewith, said nozzle being in communication with said passage at a position opposite said orifice, the ratio of the diameter of said nozzle to the diameter of said suction orifice being in the range of from 1:6 to 1:2, and means for imparting a superatmospheric pressure to said nozzle in order to push said filament or yarn into and within said suction orifice by means of a high speed pneumatic jet orthoganally incident on said filament or yarn, the speed of said pneumatic jet corresponding to the difference between said superatmospheric and subatmospheric pressures at said nozzle and said suction orifice, respectively; said passage being in communication with the atmosphere through a longitudinal slot having a width smaller than the crosssectional diameter of said passage and lying in a plane including the axis of said filament or yarn and substantially perpendicular to the common axis of said nozzle and said suction orifice, said slot allowing the introduction therethrough into said passage of said filament or yarn within said passage and in front of both said nozzle and orifice; said passage having an axis intersecting said common axis of said nozzle and suction orifice and lying within the plane of symmetry of said slot.

2. A device as claimed in claim 1, further comprising a conduit connected to a superatmospheric pressure source and a first pressure duct connected to said conduit; said pressure means comprising a second pressure duct connected to said first pressure duct and divergently joining said filament or yarn removal duct; and said means for imparting a superatmospheric pressure to said nozzle comprising a third pressure. duct joining said first pressure duct and said nozzle.

Claims

1. A device for sucking and dragging the ends of textile filaments and yarns which are cut during movement at speeds of at least 1,000 meters/minute thereof to collecting and winding equipment, said device comprising a filament or yarn removal duct having a suction orifice at one end thereof; pressure means spaced from said suction orifice to create a subatmospheric pressure condition at said suction orifice; means guiding said filament or yarn in a direction substantially perpendicular to the axis of said suction orifice and adjacent thereto; a passage having a circular cross-section surrounding said filament or yarn and communicating with said suction orifice; a nozzle having a cross-section smaller than that of said suction orifice and coaxially aligned therewith, said nozzle being in communication with said passage at a position opposite said orifice, the ratio of the diameter of said nozzle to the diameter of said suction orifice being in the range of from 1:6 to 1:2, and means for imparting a superatmospheric pressure to said nozzle in order to push said filament or yarn into and within said suction orifice by means of a high speed pneumatic jet orthoganally incident on said filament or yarn, the speed of said pneumatic jet corresponding to the difference between said superatmospheric and subatmospheric pressures at said nozzle and said suction orifice, respectively; said passage being in communication with the atmosphere through a longitudinal slot having a width smaller than the cross-sectional diameter of said passage and lying in a plane including the axis of said filament or yarn and substantially perpendicular to the common axis of said nozzle and said suction orifice, said slot allowing the introduction therethrough into said passage of said filament or yarn within said passage and in front of both said nozzle and orifice; said passage having an axis intersecting said common axis of said nozzle and suction orifice and lying within the plane of symmetry of said slot.

2. A device as claimed in claim 1, further comprising a conduit connected to a superatmospheric pressure source and a first pressure duct connected to said conduit; said pressure means comprising a second pressure duct connected to said first pressure duct and divergently joining said filament or yarn removal duct; and said means for imparting a superatmospheric pressure to said nozzle comprising a third pressure duct joining said first pressure duct and said nozzle.