Abstract:
To transfer the stitches from a first needle arc ( 7 X) to a second opposed needle arc ( 7 Y), a overturnable semicircular sector ( 19 ) presents elements ( 25 ) terminating in a bifurcate way ( 25 F) (flanking inside the respective sinkers ( 11 ) the relevant needle ( 7 X) of the first arc), each of which has an upper fork projection ( 25 A) embracing the needle ( 7 X) and forming a rear recess ( 25 X) and a front recess ( 25 C) suitable to engage an end stitch (M 1 ) formed by the corresponding needle ( 7 X), said stitch (M 1 ) then being transferred and engaged on a corresponding needle ( 7 Y) of the second needle arc.

Description:
FIELD OF THE INVENTION 
       [0001]    The invention relates to a device, which is combined with a circular knitting machine, for producing the closure of tubular hosiery articles produced by this machine. 
       BACKGROUND OF THE INVENTION 
       [0002]    Attempted solutions to this problem have not proved satisfactory. Solutions in which the articles are transferred from the production machine to a separate device have proved somewhat unsatisfactory and/or too costly and/or too bulky, especially if combined with each single machine. 
       SUMMARY OF THE INVENTION 
       [0003]    The invention solves these problems, and also achieves other objects and advantages, which are apparent from the text below. 
         [0004]    The device in question—for closing the end of hosiery articles on the same circular machine on which they are produced—is of the type of those that adopt a sector—generally semicircular—to transfer the stitches from a first needle arc to a second opposed needle arc, as defined in the Italian patent application no. FI2006A000025 of 21.01.2006, the contents of which are incorporated herein by reference. 
         [0005]    According to the invention, elements terminating in a bifurcate way are provided in said sector, each of which flanks—inside respective sinkers—the relevant needle of the first arc; each of said shaped elements terminating in a bifurcate way superiorly presents a fork projection embracing the needle and forming a rear recess and two front recesses, suitable to engage an end stitch formed by said needles. 
         [0006]    There are also provided: 
         [0007]    means to raise and lower the needles of the first arc to unload said end stitch, which thus remains engaged on said fork projection; 
         [0008]    means to rotate said sector through approximately 180° and to take the end stitches engaged on said recesses to correspond with the needles of the second arc; and 
         [0009]    means to raise said needles of the second arc to a retained level so that each of them maintains the stitch formed thereby and to engage also the corresponding stitch engaged on said recesses and to thus form ranks of double closing stitches with the needles of the second arc. 
         [0010]    Advantageously said fork projection presents the upper surface inclined. 
         [0011]    A profile can also be provided, suitable to ensure raising of the latch of the needle, during initial lowering of the needle to release the stitches that are to be transferred from the first needle arc to the second needle arc, regardless of the presence of the released stitch. 
         [0012]    A means may be provided for maintaining the shaped elements in an excluded lowered arrangement until the time of end closing of the article and for lifting the shaped elements such that the shaped elements engage the stitches on the fork shaped projections. 
         [0013]    A unit may be provided on which the sector is articulated. The assembly may be capable of rotating with the needle cylinder and to be raised and lowered axially with respect to the cylinder to reach a lowered idle position and a raised active position and to engage the stitches of the needles of the first arc and to transfer the stitches to the needles of the second arc such that the needles of the second arc engage an end stitch thereof. 
         [0014]    A tubular member may be provided for following raising and rotation of the needle cylinder. The tubular member may be partially rotated with respect to the needle cylinder for controlling overturning of the sector. 
         [0015]    The means for moving the sinkers may raise and lower the sinkers. The means for moving the sinkers and the means for raising the needles may be controlled to form tight end stitches and at least one final loose stitch in the first needle arc, and to form with the needles of the second needle arc close stitches tightened on both edges that are in a closing step and at least one final loose stitch. 
         [0016]    The invention also relates to a process for closing the end of hosiery articles on the same circular machine that produced them, with a sector—mostly semicircular—for transfer of the stitches from a first needle arc to a second opposed needle arc. 
         [0017]    The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its uses, reference is made to the accompanying drawings and descriptive matter in which preferred embodiments of the invention are illustrated. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0018]    In the drawings: 
           [0019]      FIGS. 1 to 3  are axial sectional views of the upper part of the needle cylinder with accessories and with the device of the invention, in three subsequent arrangements; 
           [0020]      FIGS. 4 ,  5  and  6  are local sectional views according to IV-IV, V-V and VI-VI of  FIG. 1 ; 
           [0021]      FIG. 7  is a sectional view of the area indicated by the arrow f VII  of  FIG. 1 , in a step prior to transfer; 
           [0022]      FIGS. 8 and 9  are local sectional views in arrangements subsequent to that of  FIG. 7 ; 
           [0023]      FIGS. 10 ,  11  and  12  are sectional views that show, analogously to  FIG. 7 , two of the arrangements prior to transfer; 
           [0024]      FIGS. 13 ,  14  and  15  are sectional views showing the area indicated by the arrow f XI  of  FIG. 3 , in subsequent operating steps implemented after transfer; 
           [0025]      FIGS. 16 and 17  are plan views of a portion of the semicircular sector isolated, without stitches and with stitches; 
           [0026]      FIG. 18  is a local sectional view according to XVIII-XVIII of  FIG. 16 ; and 
           [0027]      FIG. 19  is an enlarged detail view of  FIG. 18 , viewed from the line XIX-XIX of  FIG. 18 . 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0028]    Referring to the drawings, the reference  1  indicates a motor cylinder which rotates to draw in rotation—by means of tabs  3  or equivalent members—the needle cylinder  5 , in the external longitudinal channels  5 A of which the needles  7 X and  7 Y slide. The conventional collar  9  with radial channels  9 A for sliding of the sinkers  11  is combined superiorly with the needle cylinder  5 . Arrangement is customary. 
         [0029]    The reference  13  indicates a cylinder which is coaxial and which rotates with the motor cylinder  1  and with the needle cylinder  5 ; two diametrically opposed supports  15  are provided on the upper edge  13 A thereof, on which a semicircular sector  19  is pivoted with diametrical pins  17 ; said sector  19  is capable of overturning through approximately 180° to be arranged alternately corresponding to a first approximately semicircular needle arc  7 X and at a second and opposed needle arc  7 Y. To control overturning of the sector  19  alternately, a cylinder  21  is provided around the cylinder  13 ; the upper edge  21 A of the cylinder  21  presents at least one toothing  23  which meshes with a toothing  24  of the sector  19  and coaxial to the pins  17 . The cylinder  21  can rotate with the cylinders  13  and  5  through the action of the motor cylinder  1 , as a constraining pin  27  is provided. The cylinder  21  can be angularly displaced by a few degrees with respect to the cylinder  13 , to control overturning of the sector  19  through the toothings  23  and  24 . 
         [0030]    The two cylinders  13  and  21  and the sector  19  can be raised and lowered together axially with respect to the needle cylinder, for purposes that will be explained below; this is permitted by a vertical slot  1 Y of the cylinder  1 , through which the pin  27  that draws the two cylinders  13  and  21  in rotation passes. Also the needle cylinder  5  with the sinkers  11  can be axially displaced, to obtain prompt dimensional variations of the stitches of the tubular knitted fabric of the article. The cylinder  21  presents a limited slot  21 X ( FIG. 5 ), so that it can be made to rotate with respect to the other cylinders  13  and  1 . 
         [0031]    A customary tubular guide  31  is provided inside the cylinder  13 , to implement pneumatic tensioning of the article being formed, with a suction current. 
         [0032]    Each sinker  11  presents the customary shaped slot  11 A, to cooperate with the hook of the needle  7 X and  7 Y, for customary knitting of the tubular article of the sock or other equivalent article. 
         [0033]    At the end of forming of the tubular fabric, the toe of the article can be closed, if necessary after forming a pocket with the needles of the first arc, with continuous motion or with alternating motion of the needle cylinder. The sector  19  must then be overturned with the end edge formed by the first needle arc  7 X, until the last stitches formed by the needle arc  7 X are combined with the last stitches formed by the second needle arc  7 Y. This is implemented by the special structure of the sector  19 , suitable to cooperate with the sinkers and with the needles. 
         [0034]    The sector  19 —according to the invention—can be moved between a lowered and inactive position below the area in which the shaped slots  11 A of the sinkers  11  are located, and a raised and active position ( FIGS. 2 ,  8 ,  12 ) almost at the level of said shaped slots  11 A. In the lowered position and in the arrangement of the sector  19  in correspondence of to the needles of the first needle arc ( FIGS. 1 ,  2 ,  7 ), the circular machine can form the article in the conventional manner, with or without the end pocket for the toe to be closed. 
         [0035]    The sector  19 , along the arcuate extension thereof, presents a plurality of radial appendages  25 , each terminating with a pair of radially extending shaped elements  25 F (see in particular  FIG. 19 ); the two elements  25 F of each pair extend approximately radially to flank one of the needles  7 X of the first needle arc in the first arrangement ( FIGS. 1 and 2 ) and also one of the needles  7 Y of the second needle arc, in the second overturned arrangement ( FIG. 3 ) of the sector  19 ; the two shaped elements  25 F of each pair are located between the relevant needle  7 X and the two sinkers  11  which flank the needle and which cooperate therewith. The two shaped elements  25 F of each pair superiorly present—in the arrangement in correspondence of the first needle arc  7 X—a projection  25 A which in the plan view extends in a radially oriented U-shape open toward the outside (see in particular  FIGS. 16 to 18 ) with an upper edge  25 B which—when the sector  19  is in the raised arrangement of  FIGS. 2 ,  8 ,  9 —approximately follows the profile of the shaped slot  11 A of the relevant sinker; said edge  25 B extends outward (with respect to the axis of the cylinders) with two edges  25 C sunken toward the end of the element  25 ,  25 F following approximately laterally the bottom of the slot  11 A of the sinkers but projecting slightly with respect to said slot  11 A. 
         [0036]    In the placement described, with the element  25 ,  25 F from the arrangement of  FIGS. 7 and 10  with the needles  7 X maintained lowered without taking up thread, the sinkers  11  are moved away according to f 19  ( FIG. 11 ). In this manner, the last stitch M 1  remains engaged on the element  25 ,  25 A, so that the fabric ending with the rank of stitches M 1  can be easily transferred to the needles  7 Y of the second needle arc, with overturning of the sector  19  about the pins  17 . 
         [0037]    The needles  7 Y of the second arc are maintained idle and lowered, with the last stitch Mo engaged thereon. The needles  7 X of the first needle arc are lowered without taking up thread, so that the last formed stitches M 1  remain engaged as specified above between the recesses  25 C and  25 X; these stitches M 1  are stressed by pneumatic tensioning through suction from the tube  31 . To ensure that the latch of the needles  7 X is lowered on the end thereof, said element  26  is provided, which promptly ensures raising of the latch of the needles  7 X that start to be lowered; therefore the needles  7 X safely release the stitch M 1 , which remains retained between the recesses  25 X and  25 C. 
         [0038]    At this point—to actuate transfer of the stitches M 1  to the needles  7 Y—the cylinder  13  and therefore the sector  19  are raised and through the toothings  23 ,  24  the sector  19  is overturned through 180° about the pins  17  drawing the stitches M 1 , which remain pneumatically tensioned and thus in an elongated and also enlarged arrangement, being engaged on the respective projections  25 A extending with a radially oriented U-shape. 
         [0039]    After overturning of the sector  19  (as indicated by the broken lines in  FIG. 3 ) until reaching the position indicated in  FIGS. 3 ,  13 ,  14 , the shaped elements  25 A are positioned so as to embrace the relevant needles  7 Y of the second needle arc. At this point, the needles  7 Y of the second needle arc are raised inside the space of the respective projections  25 A to a limited level (retained level) in which said needles  7 Y maintain the stitch Mo of the last rank of stitches produced thereby but they come ( FIG. 14 ) so that they are able also to engage—together with the stitch Mo—the relevant stitch M 1 , which is enlarged by the respective projection  25 A and by the pneumatic tensioning applied by the tube  31 ; in this manner the stitches Mo and M 1  are both engaged by the relevant needles  7 Y of the second arc. At this point said needles  7 Y of the second arc—with alternating motion or with continuous motion, and with final cut of the thread, form further ranks of stitches, in particular tight stitches and a final loose stitch or another solution, to in any case prevent unraveling of the finishing ranks of the article, for example closure of the final end of the article. The article—when finished—is released. 
         [0040]    With inverse movements, all parts are returned to the initial conditions. 
         [0041]    While specific embodiments of the invention have been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles.