Patent Publication Number: US-6702218-B1

Title: Thread-feed device, comprising an adjustable thread-guide unit

Description:
FIELD OF THE INVENTION 
     The invention relates to a yarn feeder for textile machines. 
     BACKGROUND OF THE INVENTION 
     Yarn feeders are used to feed yarns to yarn using stations, such as individual knitting stations in loop-forming textile machines. The yarn feeders are separate devices, which must be secured in great numbers to the machine. Depending on the use, special demands may ensue for the yarn feeder that require a certain adaptation. From the standpoint of the manufacturer of the yarn feeder, it is therefore expedient if the yarn feeders are easily adaptable to different situations, which can result from the type of textile machine used in a given case or from a particular practical use. Adaptation should be feasible at the least possible expense and with the simplest possible means. 
     OBJECT AND SUMMARY OF THE INVENTION 
     The invention is carried out by a yarn feeder having an adjustable yarn guide arrangement. The latter includes a yarn guide element, such as a yarn eyelet, which can be adjusted between two different oblique draw-off positions relative to the yarn guide drum. Drawing the yarn off obliquely enables the traveling yarn to keep the yarn guide drum clean. The adjustment is affected along a specified path. Thus the yarn guide element can be moved to at least two different positions, in which the yarn travels along the lower rim of the yarn guide drum at different angles. With a comparatively shallower payout course, that is, in a first position in which the yarn guide element is relatively high or in other words is only slightly below the lower rim of the drum, but in turn is at a greater horizontal spacing from it, the yarn being paid out separates relatively slowly from the windings located on the yarn guide drum and is then paid out along the lower rim of the drum. This prevents the situation in which the yarn being paid out could tear the windings on the yarn guide drum down along with it. In this mode of operation, the yarn feeder is especially suitable for spun yarns, in which windings located side by side adhere relatively strongly to one another because of the filaments protruding from the yarn. 
     In a second position, the yarn guide element is at a comparatively great vertical spacing from the lower rim of the yarn guide drum but in turn is set at a lesser horizontal spacing from the pivot axis. The yarn being paid out is drawn downward relatively steeply, so that it sweeps firmly over the lower rim of the yarn guide drum. In this mode of operation, fluff deposits and rings of fiber, which could form on the lower rim of the yarn guide drum, are swept off especially well. This operation is especially suitable for continuous-filament yarns. 
     The advantage of the adjustable yarn guide element is that the payout angle of a yarn guided by the yarn guide element is adjustable. If the yarn is changed, for instance by being cut upstream of the yarn feeder and with a new yarn being spliced to the remaining end of the old yarn, then the new yarn travels through the yarn feeder to the textile machine without having to be threaded in manually. The yarn guide element can be adapted accordingly in its position to the filament properties of the yarn. 
     Another advantage is attained if an existing yarn feeler lever (i.e. shutoff means) is capable of functioning in both adjusting positions of the yarn guide element without having to be repositioned. For instance, one yarn feeler lever is disposed such that it scans the yarn in the vicinity of a fixed yarn eyelet. Any adjustment of the yarn guide element does not substantially shift the switching point of the yarn feeler. 
     The yarn feeder is furthermore preferably modularly designed. The basic device has a basic carrier, which on one end has a fastening device that is arranged for connection to the textile machine, and that at a point spaced apart from this has a rotatably supported, preferably vertically disposed shaft. The shaft is arranged on one end for connection to a yarn guide drum and on its other end is provided with a drive device. This device may be embodied by a pulley or the like. 
     A coupling device is provided on the yarn feeder, and additional modules can be connected to it. Thus the yarn feeder can be adapted to different kinds of use by means of a plurality of modules. Beginning with a basic device, a construction kit can thus be created, with which a number of additional modules can be made. For the yarn feeder manufacturer, this means that the many types required can be made using only a few basic elements. 
     Essentially, the yarn feeder is formed as a basic device by the parts that are each needed in a large number of applications. These include the basic carrier, its fastening device for connection to a machine, and a rotatably supported shaft along with a drive device, and a yarn guide drum that is preferably secured interchangeably to the shaft. Additional parts are connected to the basic carrier via one or more coupling devices. The coupling devices are disposed for instance on both sides of the shaft., which makes greater freedom of design possible for the mounting of additional modules. 
     The coupling device is preferably assigned a retaining device, with which the counterpart is retained in its desired position. The retaining device may be a clamping device, detent device, or other kind of fastening means. The clamping device can for instance be formed by a chucking device, which deforms the guide device somewhat and thus brings about clamping by frictional engagement. The result is secure bearing of the additional module and large-area transmission of force as well as seating of the additional module without rattling. The large-area force transmission makes it possible to embody the coupling device of the same plastic as the basic carrier, even if the coupling device is required to transmit some forces. 
     The additional module can be provided for receiving further elements, which are preferably retained interchangeably. If the additional module is a retainer that protrudes freely, for instance, then different yarn guide elements can be secured to it. Bearings for further supporting the shaft on the retainer can also be provided, if necessary. 
     Another additional module may for instance be a yarn brake. Depending on the application, various types of brake can be kept on hand (driven, nondriven, with magnetic clamping of the brake elements, spring clamping, etc.). A further fixture module may be a friction module, which in addition to a friction drum that feeds the yarn by frictional engagement has means for defining the wrap angle of the yarn around the yarn guide drum. For bearing the yarn guide means or similar parts that belong to the friction drum, suitable connection means may also be provided on the underside of the basic carrier. The basic carrier is preferably formed by a two-shell housing, which is divided approximately horizontally. The housing parts are then separably joined to one another, and as a result the housing interior becomes accessible. Additional devices, such as electric switches, circuits, bearings for yarn feeler levers and the like, can be accommodated in the housing interior. 
    
    
     Other objects and advantages of the invention will become apparent upon reading the following detailed description and upon reference to the drawings, in which: 
     DETAILED DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective of a modular yarn feeder in accordance with the present invention: 
     FIG. 2 is an enlarged vertical section of the yarn feeder shown in FIG. 1, provided with additional parts; 
     FIGS. 3A and 3B are perspectives of components of the coupling device of the illustrated yarn feeder; 
     FIG. 4 is a perspective of a yarn brake that can be used with the illustrated yarn feeder; 
     FIG. 5 is a side elevational view of the illustrated yarn feeder equipped with a retainer for a yarn guide tube; 
     FIG. 6 is a further side elevational view of the illustrated yarn feeder; 
     FIG. 7 is a side elevational view of the illustrated yarn feeder equipped with a friction feeder; 
     FIG. 8 is a side elevational view of the illustrated yarn feeder set for use with spun yarn; 
     FIG. 9 is a side elevational view, similar to FIG. 8, showing the yarn feeder set for use with continuous-filament yarn; and 
     FIGS. 10 and 11 are fragmentary perspective views of housing parts of the illustrated yarn feeder. 
    
    
     While the invention is susceptible of various modifications and alternative constructions, certain illustrated embodiments thereof have been shown in the drawings and will be described below in detail. It should be understood, however, that there is no intention to limit the invention to the specific forms disclosed, but on the contrary, the intention is to cover all modifications, alternative constructions and equivalents falling within the spirit and scope of the invention. 
     The yarn feeder has a basic carrier, embodied as a housing, with a fastening device  4  that serves to secure the yarn feeder  1  to a suitable retaining device, such as the retaining ring of a knitting machine. 
     The housing is constructed of two shells and has an upper housing part  5  and a lower housing part  6 , which abut one another or fit in one another at a dividing seam  7 . As seen from FIG. 2, the housing, which serves as a basic carrier  3  has two bearing seats  9 ,  10  for ball bearings  11 ,  12  for rotatably supporting a shaft  14 . The shaft is oriented approximately vertically and has a yarn guide drum  15  mounted on its lower end. This drum is preferably embodied in one piece as a deep-drawn sheet-metal part or as a ceramic part. By means of a retaining screw  17  screwed axially into a blind bore  16  of the shaft  14 , the drum is joined to the shaft  14  in a manner that prevents relative rotation. One or more drive disks  18 ,  19  are disposed on the upper end of the shaft  14 ; via bearing devices. The disks  18 ,  19  are rotatably supported on the shaft  14 , and they can be coupled to the shaft for rotation as needed by means of a coupling disk  21 . 
     The bearing seats  9 ,  10  are formed by tubular extensions on the upper and lower housing parts  5 ,  6 . They are aligned with one another and have a cylindrical chamber, opening toward the outside, for receiving the respective ball bearing  11 ,  12 . To assure the alignment of the two bearing seats  9 ,  10  to one another, a tubular extension  22  extending through the interior of the housing and surrounding the shaft  14  is provided on the lower housing part  6 . The tubular apperture  22  engages a corresponding receptacle  23  formed in the upper housing part  5  the extension  22  and the receptacle  23  fit together without play in one another. 
     A plurality of coupling devices  27  for securing additional modules are provided on the basic carrier  3 . The coupling device  25  is embodied on the basic carrier  3  between the shaft  14  and the fastening device  4  and is shown separately in FIG.  3 . The coupling device  25  includes a guide plate  28 , which is disposed parallel to a housing face  29  and is solidly joined to the housing part  5  via ribs  31 ,  32 . The guide plate  28 , with the guide face  29  and with its side toward the guide face  29 , defines two guide grooves  33 ,  34 . 
     A portion  28   a  of the guide plate  28  protruding freely past the rib  32  forms a fastening or clamping device for a foot that is meant to be slipped onto the guide plate  28 . Leading through an opening  37  is a fastening screw  38  whose head is braced on a suitable annular shoulder  39  formed on the lower housing part  6 . If the screw  38  is tightened, this causes a certain deformation of the guide plate portion  28   a.    
     In the yarn feeder shown in FIGS. 1 and 2, the coupling device  25  includes a blind cap  41 , which if needed completely covers the coupling device  25 . The clamshell-like blind cap  41  has an interior  42 , in which two opposed clamping cleats  43 ,  44  extend that define a slit. These cleats are arranged for being thrust into the guide grooves  33 ,  34 . Once the blind cap  41  has been slipped in this way onto the coupling device  25 , the fastening screw  38  can be tightened, causing the portion  28   a  to firmly clamp the blind cap  41  with its clamping cleats  43 ,  44 . In the same way as the blind cap  41 , other additional modules can be secured to the coupling device  25  and have a foot whose internal shape conforms to the internal shape of the blind cap  41 . One such additional module can be seen in FIG. 5. A retainer  46  is secured on the basic carrier  3  and fits over the drive disks  18 ,  19 ; on its free end  47 , it has a spring clamp  48  for securing a yarn guide tubule  49 . Still other devices can be secured to the arm  46  as needed. 
     The coupling device  26  shown in FIG. 2 serves for instance to secure a brake module  51 . The coupling device  26  is formed by an approximately rectangular recess or pocket, into which the brake module is inserted by a base  52 . The base  52  is guided and positioned by the side faces of the recess formed in the housing part  5 . By means of a clamping screw  53 , provided in the immediate vicinity of the recess, the base  52  is retained in the recess. 
     The break module  51  is shown separately in FIG.  4 . Its base  52  has two parts  56 ,  57 , which are joined via a film hinge  54  and can be locked to one another. This purpose is served by a detent cleat  58 , formed on the front free face end of the part  56 , and a corresponding detent recess  59  in the other part  57  is associated with this cleat. 
     The two parts  56 ,  57  serve the purpose of an axially displaceable bearing of a brake carrier  61 , which is formed by a bent wire element. This element has two legs  62 ,  63 , parallel to one another, which are displaceably supported in suitable guides. The leg  62  is braced on the part  57  via a compression spring  64  and prestresses the brake carrier  61  in one direction (toward the shaft  14 ; see FIG.  2 ). On its free end, the leg  62  has a tappet  66 , which cooperates with a cam provided on the shaft  14 . 
     Outside the base  62 , the brake carrier  61  is provided with a molded yarn guide piece  68 , which via a rib  69  carries two brake disks  71 ,  72 , which are supported freely rotatably on the rib. The break disks  71 ,  72  adhere magnetically to one another. 
     Additional fixtures may be a knot catcher  73  and a yarn inlet eyelet  74 , which are both retained by the fastening screw. As FIG. 1 shows, the yarn inlet eyelet  74  is open, so that the yarn  2  can simply be placed in it from the side. The knot catcher  73  is formed for instance by a metal sheet provided with a narrow slit. The fastening screw  53  can also serve to retain a yarn inlet eyelet  75 , which is disposed on an arm  76  above the drive disk  18 . 
     The coupling device  27  is formed by the outer conical or cylindrical face of a tubular extension, which extends into the interior of the yarn guide drum  15 . As FIG. 6 or FIG. 2 also shows, the yarn guide drum  15  is therefore placed with its upper rim relatively far away from the underside of the housing part  6 , approximately at the same level as a yarn guide eyelet  78 , which is molded as a fixed yarn guide eyelet on the lower housing part  6 . The interstice can be closed by a cover hood  79 , which is slipped for instance onto the extension  10 . As FIG. 7 shows, the yarn guide drum  15  can be supplemented with or replaced by a friction module  80 . The friction module  80  includes the yarn guide drum  15  and a friction disk  81  joined to the drum in a manner fixed against relative rotation. The friction unit  80  also includes a setting lever  82 , which has a yarn guide eyelet  83  at approximately the level of the transition between the friction disk  81  and the yarn guide drum  15  and otherwise extends radially to the pivot axis of the shaft  14 . For pivotable bearing of the lever  82 , clamping rings  84 ,  85  are slipped onto the coupling device  27  and seated on it; between them, they clamp an annular bearing region of the lever  82 . The annular bearing region may be provided with one or more protrusions that engage corresponding recesses in the clamping rings  84 ,  85 , in order to fix the lever  82  in various detent positions. 
     In order to set the yarn feeder  1  for friction operation, in many cases an outlet brake  91  is expedient or required. This brake is preferably disposed between two yarn guide eyelets  93 ,  94  on the outlet side. For fastening the outlet brake  91  detachably to the yarn feeder, a base  95  is used, which is provided with a threaded opening and is located below the fastening device  4 . This allows the outlet brake to be screwed on. It has a lower, approximately horizontally disposed brake disk, which is carried by a pin  97  provided with an opening. An upper brake plate is supported displaceably in the direction of the arrow on this pin and can be locked in its upper position. This disk, by its own weight, presses the yarn  2  against the brake disk  96 . 
     The yarn feeder  1  has an adjustable yarn guide arrangement for the yarn guide eyelet  93 . To explain the structure and function, reference will be made below to FIGS. 8 through 11. As seen from FIGS. 8 and 9, the yarn guide eyelet  93  can be moved to at least two different positions and locked in those positions. In the first position, shown in FIG. 8, the yarn guide eyelet  93  is located a short distance below a plane E, defined by the lower rim of the yarn guide drum  15 , and is retained at a relatively large spacing from the pivot axis D of the drum. The preferably rectilinear path W along which the yarn guide eyelet  93  is adjustable or displaceable forms an acute angle with the pivot axis D, as shown in FIG.  9 . 
     The yarn guide eyelet  93  is carried by two substantially parallel wire legs  105  extending away from it, which are guided in a slot  106  formed in the housing. The slot  106 , as shown in FIGS. 10 and 11, is formed between the upper housing part  5  and the lower housing part  6 . For each leg  105 , there is one slot  106  on each side of the housing. In FIGS. 10 and 11, the same reference numerals are therefore used for the slots  106  and their details, and the description applies equally to both slots  106 . 
     The slot  106  includes a pocket, which is formed between the upper housing part  5  and the lower housing part  6  and is open toward the bottom. The pocket is formed on the part of the housing part  5  by two groove-like or channel-like indentations  107 ,  108 , between which a protrusion  109  is formed that is aimed at a corresponding cheek  111  of the lower housing part  6 . Between the cheek ill and the protrusion  109 , however, a gap remains, through which the applicable wire leg  105  can be thrust. The wire legs  105  yield outward, however, so that on both ends of their path, which are formed by the indentations  107 ,  108 , they snap into place. The channel-like indentations  107 ,  108  are thus both detent and guide means at the same time, because they support the wire legs  105  nonpivotably. The wire legs  105  are also seated axially nondisplaceably in the slot  106 . To that end, ends bent inward or angled in some other way are formed on the wire legs  105  and engage the cheek  111 , for instance, from behind, the cheek being embodied as flat itself and extending between to outward-protruding ribs  114 ,  115 . As needed, the ribs  114 ,  115  can either engage the indentations  107 ,  108  or adjoin them. The narrow ribs  114  can for instance engage the indentation  108  and thus with their inner flank can determine the alignment of the wire leg  105 . The vertical orientation of the yarn guide eyelet  93  is thus associated with the lower housing part  6 . The yarn guide eyelet  93  preferably allows a certain lateral play for the yarn but is disposed centrally on the housing. The yarn  2  traveling away from the yarn guide eyelet  93  and the pivot axis of the yarn guide drum  19  are thus preferably both located in the same plane. The yarn feeder of FIG. 1 described thus far functions as follows: 
     In operation, the yarn  2  is put in place and threaded into the yarn feed, as shown. The yarn  2  extends through the inlet eyelet  74 , through the space between the brake plates  71 ,  72 , to the yarn eyelet  78 , and the yarn  2  in the interstice holds a yarn feeler lever  100 , here supported pivotably, in a raised position. Beginning at the yarn eyelet  78 , the yarn  2  passes in multiple windings around the yarn guide drum  15  and then travels, obliquely sweeping the lower rim of the drum to the textile machine via the yarn guide eyelets  93 ,  94 . Between the yarn guide eyelets  93 ,  94 , a further yarn feeler lever  101  rests on the yarn, in order to monitor its tension. The yarn feeler lever  101  is connected to a switch, which furnishes a switching signal whenever the yarn feeler lever  101  drops below a minimum height. 
     The yarn feeler lever  101  is disposed such that when the yarn is held taught, in each setting position of the yarn guide element  93 , it is held in the same or at least nearly the same position. The rated position of the feeler lever  101  is as a result independent of the setting of the yarn guide element  93 . This is attained by means of a pivotable bearing of the yarn feeler lever  101  in the vicinity of the pivot axis D and by a relatively long lever length; the yarn  2  is scanned in the vicinity of the fixed yarn guide eyelet  94 . If needed, further yarn feeler elements may be provided, whose rated and switching positions are equally unaffected by the adjustment of the adjustable yarn guide arrangement. 
     In operation, the yarn guide drum  15  is driven to rotate and thus feeds specified quantities of yarn. For instance, if a spun yarn, which has relatively many filaments protruding from the yarn, is to be processed, then the setting of the yarn feeder  1  as shown in FIG. 8 is preferred. The yarn guide eyelet  93  here is in an upper position at a relatively slight spacing below the plane B, but at a greater spacing from the pivot axis D. The yarn  2  is drawn off relatively shallowly and thus deviates rather slowly from the package located on the yarn guide drum  15 . This prevents the yarn  2  being paid out from tearing windings of the package downward. 
     If a comparatively smooth continuous-filament yarn is to be processed, then the yarn  2  is torn off upstream of the yarn feeder  1 , and the new yarn is knotted to the end of the old yarn. Furthermore, for setting to the smoother continuous-filament yarn, the yarn guide eyelet  93  is transferred downward to the position shown in FIG. 9, in which it is farther away from the plane B but in turn closer to the pivot axis D. This spacing, however, is still greater than the diameter of the lower rim of the yarn guide drum  15 . The yarn is now drawn off relatively steeply, so that it reliably sweeps over the rim of the yarn guide drum  15  and strips off any fluff or the like present there. 
     For adjusting the yarn guard eyelet, the wire legs  105  are pressed together, counter to their own spring force, so that they emerge from the respective indentations  107  and  108  (see FIG.  10 ). The element formed by the yarn guide eyelet  93  and the wire legs  105  can be displaced in this condition along the path W. Once it is released at the end of the path, the wire legs  105  snap back into the respective indentations  107  or  108 , and the yarn guide eyelet  93  is locked in its new position. The path W can be linear, or in other words a straight line. If needed, it can also be curved, for instance by disposing the yarn guide eyelet  93  on the end of a pivotably supported arm. 
     If needed, intermediate positions can be provided, by forming suitable grooves in the protrusions  109 . If the yarn guide drum  15  is replaced with the friction unit  80  of FIG. 7, then the yarn  2  wrapping around the friction disk  81  is correspondingly carried along and advanced. Replacing the yarn guide drum  15  with the friction unit  80  thus makes it possible to vary the functional principle. 
     The brake module  51  can also be replaced by a non-driven yarn brake module. The yarn feeder  1  can also be refitted by removing the blind cap  41  and replacing it with the arm  46  (FIG.  5 ). 
     From the foregoing, it can be seen that in the modular yarn feeder  1 , the basic carrier  3  is a basic component of the apparatus on which additional modules can be secured as needed by suitable coupling devices. This makes the yarn feeder more adaptable to different kinds of use and situations.