Patent Publication Number: US-6986316-B2

Title: Device for precise placement of the toe of a hosiery item during automated insertion thereof in the conveyor of a sewing machine for closing the toe

Description:
BACKGROUND OF THE INVENTION 
   U.S. Ser. No. 10/459,526 to which reference is made for the sake of completeness, discloses a double-cylinder circular hosiery knitting machine equipped with a device which, at the end of the formation of the hosiery item, extracts from the machine such hosiery item, which is turned inside out and is aspirated into the upper needle cylinder, and automatically inserts it, with the portion of its toe that must be closed, into the conveyor of a sewing machine. 
   The device that transfers the hosiery item from the double-cylinder circular machine to the conveyor of the sewing machine comprises two grippers, which can engage two diametrically opposite regions of the opening of the toe of the hosiery item to be closed by sewing, so as to hold the hosiery item so that it hangs at its toe to be sewn. The two grippers can be moved apart on command, after engaging the toe of the hosiery item, so as to flatten and move closer the two flaps of the open toe that must be joined by sewing in order to close the toe of the hosiery item. 
   The two grippers insert the portion of the hosiery item that lies proximate to the opening of the toe to be closed into the conveyor of a sewing machine, which is constituted by two laminas that are arranged side by side on a substantially horizontal plane, so as to form between them a passage for the portion of such hosiery item. 
   The region of the hosiery item that ends at the toe to be closed is generally produced by providing an additional portion with respect to the actual hosiery item, which is used during the placement of the hosiery item on the sewing machine and is designed to be removed during sewing. This additional portion is composed, starting from the body of the hosiery item, of a few rows of knitting formed with an elastic thread that has a reduced diameter and of a final border that is thicker than said rows. The hosiery item is gripped by the grippers at the thicker border and is dragged by the grippers, which move above the laminas of the conveyor of the sewing machine, so that the insertion of the toe of the hosiery item in the passage formed between the laminas occurs so that the thicker border is arranged above said laminas and the region that is formed with elastic threads of reduced diameter, and therefore has a reduced thickness, is located at the passage formed between the laminas. 
   In order to achieve a good result in sewing, the thicker border must rest along its entire extension against the upper side of the laminas of the conveyor. This is the only way in which the sewing line or lines will affect the first rows of knitting of the actual hosiery item and the additional hosiery item portion will be removable substantially completely, achieving a scarcely visible seam. 
   SUMMARY OF THE INVENTION 
   The aim of the present invention is to provide a device that allows to achieve extremely precise placement of the toe of the hosiery item during its automated insertion in the conveyor of a sewing machine, so as to have a fully satisfactory result in the subsequent sewing operation for closing the toe of the hosiery item. 
   Within this aim, an object of the invention is to provide a device that allows to rest, along its entire extension, the thicker border of the additional portion of the toe of the hosiery item against the upper side of the laminas of the conveyor. 
   Another object of the invention is to provide a device that can have a modest space occupation, so that it can be easily applied proximate to conveyors of sewing machines of limited size. 
   Another object of the invention is to provide a device that ensures high precision and reliability in operation even if the thickness of the hosiery items to be processed varies. 
   This aim and these and other objects that will become better apparent hereinafter are achieved by a device for precise placement of the toe of a hosiery item during its automated insertion in the conveyor of a sewing machine for closing the toe, said conveyor being composed of two laminas that are arranged side by side on a substantially horizontal plane so as to form between them a passage for a portion of the hosiery item proximate to the toe to be closed by sewing, characterized in that it comprises, proximate to the inlet of said passage, tensioning means, which are arranged below said pair of laminas and can engage a portion of the hosiery item that hangs at the opening of the toe to be closed by sewing so that the two flaps of the opening face each other, said tensioning means being actuatable in order to tension the hosiery item downwardly during its insertion into said passage. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Further characteristics and advantages of the present invention will become better apparent from the description of a preferred but not exclusive embodiment of the device according to the invention, illustrated by way of non-limiting example in the accompanying drawings, wherein: 
       FIG. 1  is a partially sectional front elevation view of the device according to the invention, prior to the engagement of the tensioning means with the hosiery item; 
       FIG. 2  is a partially sectional top plan view of the device according to the invention in the operating condition that corresponds to  FIG. 1 ; 
       FIG. 3  is a sectional view of  FIG. 2 , taken along the line III—III; 
       FIG. 4  is a partially sectional front elevation view of the device according to the invention, with the tensioning means engaged with the hosiery item prior to its insertion in the passage of the conveyor; 
       FIG. 5  is a top plan view of the device according to the invention in the operating condition that corresponds to  FIG. 4 ; 
       FIG. 6  is a sectional view of  FIG. 5 , taken along the line VI—VI; 
       FIG. 7  is a partially sectional front elevation view of the device according to the invention during insertion of the hosiery item in the passage of the conveyor; 
       FIG. 8  is a top plan view of the device according to the invention in the operating condition that corresponds to  FIG. 7 ; 
       FIG. 9  is a sectional view of  FIG. 8 , taken along the line IX—IX; 
       FIG. 10  is a perspective view of one of the tensioning means; 
       FIG. 11  is a perspective view of the tensioning means. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   With reference to the figures, the device according to the invention, generally designated by the reference numeral  1 , is designed to be fitted proximate to the inlet of the passage  2  of the conveyor of a sewing machine for closing the toe of hosiery items by sewing. 
   The conveyor of the sewing machine is composed, in a per se known manner, of two laminas  3   a ,  3   b  that lie on a substantially horizontal plane and are arranged laterally side by side so that the passage  2 , in which a portion of the hosiery item  4  proximate to the toe to be closed by sewing must be inserted, is formed between said laminas. 
   The hosiery item  4  is preferably formed, in a per se known manner, at the open toe that is designed to be closed by sewing, with an additional portion that is constituted, starting from the body  4   a  of the hosiery item and continuing toward the end or toe to be closed by sewing, by a certain number of rows of knitting  4   b , which are formed with an elastic thread of reduced diameter so as to have a reduced thickness, and with a final border  4   c,  which is made of threads having a larger diameter so as to be significantly thicker than at the rows  4   b  and thicker than the width of the passage  2 . 
   The hosiery item  4 , upstream of the device according to the invention along its direction of insertion within the passage  2 , designated by the arrow  5 , hangs, at the toe to be closed, from a pair of grippers  6   a,    6   b,  which are inserted in the opening of the toe and engage two diametrically opposite regions of the border  4   c.  The grippers  6   a  and  6   b  may be constituted for example by the grippers disclosed in U.S. Ser. No. 10/459,526 cited above, or by other grip and support means capable of inserting the hosiery item in the passage  2 . 
   The grippers  6   a ,  6   b  can move apart, so as to tension the hosiery item  4  at the opening of the toe to be closed in order to flatten the two flaps of the opening that face each other, arranging the toe of the hosiery item in a condition that is suitable for its insertion into the passage  2  between the pair of laminas  3   a ,  3   b.    
   The device according to the invention comprises tensioning means, which are arranged below the pair of laminas  3   a ,  3   b  and can engage a portion of the hosiery item  4  that hangs at the opening of the toe to be closed by sewing so that the two flaps of the opening face each other. The tensioning means can be actuated in order to tension the hosiery item  4  downwardly during its insertion into the passage  2 . 
   The tensioning means can engage the outer sides of the two flaps of the hosiery item  4 , so as to make the border  4   c  rest, substantially along its entire extension, against the upper face of the laminas  3   a ,  3   b  during the insertion of the hosiery item  4  in the passage  2 . 
   The tensioning means preferably comprise a pair of rollers  10 ,  11 , which contrarotate about respective axes  10   a,    11   a,  which are substantially horizontal and parallel to the longitudinal axis of the passage  2 , i.e., parallel to the insertion direction  5 . The rollers  10 ,  11  face with their lateral surface, on opposite sides, an imaginary vertical plane that passes through the longitudinal axis of the passage  2 , so as to face the outer sides of the two mutually facing flaps of the hosiery item  4  during its insertion into the passage  2 . 
   The pair of rollers  10 ,  11  comprises a first roller  10 , which can be rotationally actuated about its own axis  10   a,  and a second roller  11 , which is supported so that it can rotate freely about its own axis  11   a  and can rotate by contact with the first roller  10  with the interposition of the two flaps of the hosiery item  4 . 
   More particularly, the first roller  10  is keyed to the end of a shaft  12  that is supported, so that it can rotate about its own axis, which coincides with the axis  10   a,  by a supporting structure  13  by interposing bearings  14 . A pulley  15  is keyed to the end of the shaft  12  that is opposite with respect to the end provided with the roller  10 ; said pulley is connected, by means of a belt  16 , to a motor shaft  17 , which can be actuated, for example by means of an electric motor, so that it rotates about its own axis, so as to turn the roller  10  about its own axis  10   a.    
   The shaft  17  can be actuated autonomously or can be connected to the motor that drives the various components of the sewing machine. 
   The second roller  11  is substantially cylindrical, with an initial portion  11   b,  starting from its axial end that is first reached by the hosiery item  4  in its advancement toward the passage  2 , which is shaped like a frustum, with a diameter that gradually increases along the direction of advancement  5  of the hosiery item  4  toward the passage  2 . 
   The first roller  10  has a shape provided with a substantially cylindrical main lateral surface and with at least one tooth that protrudes radially from said lateral surface. 
   Preferably, the first roller  10  has a first tooth  18  and a second tooth  19 , which protrude radially from its main lateral surface and are angularly spaced with respect to each other about the axis  10   a  of the first roller  10 . 
   The first tooth  18  has a profile that is contoured like a portion of a conical surface whose axis coincides with the axis  10   a,  with a diameter that increases along the direction of advancement  5 . The first tooth  18 , which covers a limited portion of the axial extension of the first roller  10  starting from the axial end of the roller  10  that is first reached by the hosiery item  4  in its advancement along the direction  5 , laterally faces, during the rotation of the first roller  10  about its own axis  10   a,  the initial portion  11   b  of the second roller  11 . 
   The second tooth  19  has, starting from the axial end of the roller  10  that is first reached by the hosiery item  4  in its advancement along the direction  5 , a first portion  19   a  that is substantially shaped like the first tooth  18  and a second portion  19   b  that is formed as a continuation of the first portion  19   a  and is substantially shaped like a portion of a cylindrical surface whose axis coincides with the axis  10   a.  The second portion  19   b  laterally faces, during the rotation of the first roller  10  about its own axis  10   a,  the cylindrical portion of the second roller  11 . 
   The second roller  11  is arranged at such a distance from the first roller  10  that the first roller  10 , in rotating about its own axis  10   a,  does not substantially hinder, with its main lateral surface, the advancement motion of the hosiery item  4  toward the passage  2 . 
   Conveniently, means are provided for adjusting the minimum distance of the second roller  11  from the first roller  10 . 
   Moreover, elastic means are provided that elastically contrast the movement of the second roller  11  away from the first roller  10  due to the insertion of the hosiery item  4  between the two rollers  10  and  11 . 
   More particularly, the second roller  11  is mounted, with an interposed bearing  20 , on a shaft  21 , fixed to the end of a lever  22 , which is pivoted, in an intermediate region of its extension, to a supporting element  23  about a rotation axis  22   a  that is parallel to the axes  10   a,    11   a  of the rollers  10 ,  11 . 
   At the end of the lever  22  that lies opposite the end that supports the second roller  11  there is a grub screw  24 , which rests against a fixed abutment  25  of the supporting element  23 , delimiting the rotation of the lever  22  about the axis  22   a  in the direction of rotation that makes the second roller  11  approach the first roller  10 , constituting thus the distance adjustment means. The position of maximum approach of the roller  11  to the roller  10  can be adjusted, by acting on the grub screw  24 , so that the first roller  10 , when it faces the second roller  11  with its main lateral surface, does not substantially hinder the advancement of the hosiery item  4  along the direction  5 . 
   A piston  26  acts on the lever  22  and is pushed by elastic means, in particular by a spring  27  that elastically contrasts the rotation of the lever  22  about the axis  22   a  in the direction of rotation that moves the second roller  11  away from the first roller  10 . The loading of the spring  27  can be adjusted by elastic force adjustment means, in particular constituted by a screw  28 . 
   The position of the rollers  10 ,  11  with respect to the laminas  3   a ,  3   b  of the conveyor of the sewing machine is such that an imaginary vertical plane that is perpendicular to the longitudinal axis of the passage  2  and passes through the insertion end of the passage  2  intersects an intermediate region of the axial extension of the cylindrical region of the second roller  11  and of the portion  19   b  of the second tooth  19  of the first roller  10 . 
   Preferably, at least the lateral surface of the cylindrical portion of the second roller  11  has a surface with increased friction, in particular a knurled surface in order to increase the grip of the roller  11  against the hosiery item  4 . 
   Operation of the device according to the invention is as follows. 
   The hosiery item  4 , which hangs from the grippers  6   a ,  6   b  with its border  4   c  held at a slightly higher level than the plane of arrangement of the laminas  3   a ,  3   b , is moved, so that the two flaps of the opening of the toe face each other and are aligned with the passage  2 , along the direction  5  in order to insert it in the passage  2  at the region affected by the rows  4   b  ( FIGS. 1  to  3 ). 
   In its advancement toward the passage  2 , the hosiery item  4  is inserted between the rollers  10 ,  11 . The first roller  10 , actuated with a rotary motion about its own axis  10   a,  during the advancement of the hosiery item  4  toward the passage  2  cyclically affects, with the teeth  18 ,  19 , the hosiery item  4 , pressing it against the second roller  11 , which is thus turned about its own axis  11   a  ( FIGS. 4  to  6 ). 
   It should be noted that the initial portion  11   b  of the second roller  11  and the shape of the first tooth  18  and of the portion  19   a  of the second tooth  19  of the roller  10  constitute a guide for the correct insertion of the hosiery item  4  between the rollers  10  and  11 , while the cylindrical portion of the second roller  11  and the portion  19   b  of the second tooth  19  of the first roller  10  engage the outer sides of the two mutually facing flaps of the hosiery item  4 , pulling them downwardly while the hosiery item  4  is inserted in the passage  2  ( FIGS. 7  to  9 ). 
   This traction has the effect of achieving the reliable resting, over its entire extension, of the border  4   c  against the upper face of the laminas  3   a ,  3   b , achieving excellent precision in the placement of the hosiery item  4  during its insertion in the passage  2 . 
   The tension applied by the rollers  10 ,  11  to the hosiery item  4  also has the effect of further reducing the thickness of the rows  4   b , facilitating the insertion of said rows in the passage  2 . 
   It should be noted that the particular shape of the first roller  10  achieves a cyclic engagement of the rollers  10 ,  11  with the hosiery item  4 , so as to allow the hosiery item  4  to advance along the passage  2 . The degree of downward tension applied to the hosiery item  4  is proportional to the ratio between the rotation rate of the roller  10  and the advancement speed of the grippers  6   a ,  6   b  along the direction  5 . 
   After the hosiery item  4  has been inserted completely into the passage  2 , the action of the rollers  10  and  11  on the hosiery item  4  ceases, and the hosiery item is made to advance along the passage  2  by the traction means with which the sewing machine is equipped. 
   It should be noted that the minimum distance between the rollers  10  and  11  can be adjusted, according to the thickness of the hosiery item  4 , by acting on the grub screw  24 , and the pressure of the rollers  10  and  11  on the hosiery item  4  can be adjusted by acting on the adjustment screw  28 . 
   In practice it has been found that the device according to the invention fully achieves the intended aim, since by ensuring precise resting of the end border of the toe of the hosiery item to be sewn against the upper face of the laminas of the conveyor of the sewing machine it ensures the correct placement of the hosiery item in input to the sewing machine and therefore ensures correct execution of the seam, leading to a fully satisfactory sewing result. 
   Although the device according to the invention has been conceived in particular in order to equip a machine of the type disclosed in U.S. Ser. No. 10/459,526, it can in any case be used more generally to equip conveyors arranged in input to sewing machines of a known type, in order to achieve a precise placement of the hosiery item during its insertion into the conveyor. 
   The device thus conceived is susceptible of numerous modifications and variations, all of which are within the appended claims; all the details may further be replaced with other technically equivalent elements. 
   In practice, the materials used, as well as the dimensions, may be any according to requirements and to the state of the art. 
   The disclosures in Italian Patent Application No. MI2003A000896 from which this application claims priority are incorporated herein by reference.