BACKGROUND OF THE INVENTION  
         [0001]    The present invention relates to an apparatus for finishing pieces cut from a length of textile material unwound from a roll by sewing their leading edge, particularly for closing the leading edge of a tubular piece.  
           [0002]    Hereinafter, for the sake of convenience of presentation, the term “length” is understood to designate woven or non-woven textile articles of different kinds, composed of one or more layers, even tubular and mutually different as for quality and consistency, while the term “piece” is understood to designate a portion cut from said length of textile material.  
           [0003]    In the preparation of pieces of textile material, particularly padded pieces as used for example to cover mattresses or to prepare quilts, the need is felt to finish the leading edge in order to keep the various layers of the piece properly superimposed one another and avoid staggering of the edges, so that the piece can be positioned easily for the subsequent processes.  
           [0004]    This need is felt even more when the pieces are cut from a length of textile material composed of multiple layers and unwound from a roll, or when the length of textile material is prepared by joining multiple layers unwound from respective rolls.  
           [0005]    Tubular pieces are also known which are used to cover, for protective purposes, blocks of rubber latex, for example in the manufacture of mattresses.  
           [0006]    Such tubular pieces, once cut to size from the unwound length of textile material, must be closed at one end so as to form a pouch for containing the latex block.  
         SUMMARY OF THE INVENTION  
         [0007]    The aim of the present invention is therefore to provide an apparatus that is suitable to be inserted in a line for producing pieces of textile material, particularly tubular pieces, and allows to meet this requirement.  
           [0008]    Within this aim, an object of the present invention is to provide an apparatus that is relatively simple to manufacture and therefore economically advantageous.  
           [0009]    This aim and this and other objects which will become better apparent hereinafter, are achieved with an apparatus for finishing a piece cut from a length of textile material unwound from a roll by sewing its leading edge, particularly for closing the leading edge of a tubular piece, characterized in that it comprises: means for causing the advancement of said length of textile material, suitable to unwind two successive portions of the length of material, for a total longitudinal extension equal to the longitudinal extension of said piece; cutting means, arranged downstream of said advancement means and suitable to cut a piece from said length of textile material with a cut that is perpendicular to said unwinding direction and forms the rear edge of the cut piece and the leading edge of the length of textile material to be unwound; positioning means, arranged downstream of said cutting means and suitable to arrange the leading edge of said unwound length of material with respect to a sewing machine; said advancement, cutting and positioning means being coordinately operatable so that: in a first step, said advancement means unwinds said length of material for a said first portion whose longitudinal dimension is such that said leading edge is engaged in said positioning means; in a second step, said positioning means is actuated so as to position said leading edge in alignment with the sewing path of said sewing machine; in a third step, said sewing machine is actuated so as to produce a stitched seam along said leading edge; in a fourth step, said advancement means unwinds a said second portion from said length of material; and in a fifth step, said cutting means cuts a piece from said length of material. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]    Further characteristics and advantages of the present invention will become better apparent from the following description of a preferred embodiment thereof, illustrated only by way of non-limitative example in the accompanying drawings, wherein:  
         [0011]    [0011]FIG. 1 is a partially schematic perspective view of the apparatus;  
         [0012]    [0012]FIG. 2 is an axial schematic view of the apparatus of FIG. 1 in the initial condition of the operating cycle;  
         [0013]    [0013]FIG. 3 is an enlarged-scale view of a detail of FIG. 2;  
         [0014]    [0014]FIGS. 4, 5,  6  and  7  are schematic views of the apparatus of FIG. 1 in four successive operating situations;  
         [0015]    [0015]FIG. 8 is a view of a second embodiment of the apparatus;  
         [0016]    [0016]FIGS. 9, 10,  11 ,  12 , and  13  are schematic views of a third embodiment in five operating situations. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0017]    Specifically with reference to FIG. 1, the apparatus comprises means (not shown) for rotatably supporting a roll  1  on which a length of textile material  2 , from which the pieces to be finished will be obtained, is wound. The length of material  2  is constituted for example by a tubular article for wrapping latex mattresses, or by a plurality of superimposed layers. In this last case, the length of material, instead of being pre-manufactured and wound on a single roll, can be produced by conveying and coupling at the inlet of the apparatus individual layers unwound from a corresponding number of rolls.  
         [0018]    The length of material  2  is unwound from the roll  1  in the direction A by means of an advancement assembly generally designated by the reference numeral  3 . Said assembly  3  is composed of two parallel grip rollers  4  and  5 , between which the length of material is guided from above. The rollers  4  and  5  are perpendicular to the direction A and have, at one end, respective gears  6  and  7  that mesh with each other and are actuated so as to rotate in opposite directions by means of an electric motor  8  and a transmission composed of a belt  9  wound on a pair of pulleys that are keyed respectively to the output shaft of the electric motor  8  and on the roller  4  adjacent to the gear  6 .  
         [0019]    Below the grip and unwinding assembly  3  and at the rear of the length of textile material  2 , a rail  10  is provided, which is parallel to the rollers  4  and  5  and acts as a sliding guide for a carriage  11  that comprises a bracket on which an electric motor  12  is supported, said motor having a shaft with a vertical axis that protrudes upward. A disk-like blade  13  is keyed to the shaft  12  and intersects the plane of the length of material  2  below the rollers  4  and  5 .  
         [0020]    The carriage  11  is rigidly coupled to a portion of a transmission belt  14  that is parallel to the rail  10 . The belt  14  is wound in a closed loop around a driven pulley  14   a  and around a driving pulley  15  actuated by an electric motor  16 .  
         [0021]    At the rear of the length of material  2 , i.e., on the side engaged by the roller  4 , and below the grip and unwinding unit  3 , there is an abutment bar that is parallel to the roller  4  and is composed of two L-shaped profiled elements  17   a  and  17   b,  between which there remains a gap  17   c  along which the blade  13  can slide. Opposite the abutment bar  17   a  and  17   b , but on the opposite side of the length of material  2 , there is a locking bar  18 , constituted by a profiled element that has a C-shaped cross-section with two superimposed longitudinal wings  18   a  and  18   b  that delimit a longitudinal gap  18   c  that is directed toward the length of material  2  and faces the gap  17   c . The profiled element  18  is supported, at the level of the circular blade  13 , by two pneumatic actuators  19  and  20 , which are suitable to move it between a position that is spaced from the length of material  2  and a position for locking the length of material  2  between the profiled elements  17   a  and  17   b  and the wings  18   a  and  18   b  in order to allow the blade  13  to slide in the gaps  17   c  and  18   c  during the cutting of the end portion of the piece  2  that will constitute the piece to be finished.  
         [0022]    Below the bar  10  and parallel thereto there is an abutment bar  21  to which a plurality of equidistant elastic tabs  22  are fixed. The tabs  22  are substantially perpendicular to the plane of the length of material  2  and protrude so as to form a sort of comb.  
         [0023]    Proximate to the bar  21 , but at the rear of the length of textile material  2 , a strip  23  is articulated which is actuated by pneumatic actuators  24  capable of imparting to the strip an oscillation of 90° between a vertical position and a horizontal position. In the vertical position, the strip  23  is flush with the length of material  2 , while in the horizontal position the strip  23  arranges itself below the tabs  22  and so that its free edge coincides with the ends of the tabs.  
         [0024]    In front of the abutment bar  21  and parallel thereto there is a rail  24   a  that acts as a guide for a slider  25 . The slider  25  supports a sewing machine  26  whose working plane is co-planar to the plane formed by the tabs  22 .  
         [0025]    The slider  25  is actuated with a reciprocating motion along the rail  24   a  so that the sewing machine  26  can be moved from one end to the other of the abutment bar  21 . For the actuation of the slider  25  along the rail there is an electric motor  27  provided with a vertical output shaft on which a driving pulley  28  is keyed. A belt  29  is wound around the driving pulley  28  and is closed in a loop around a driven pulley  30 . The portion of the belt  29  is parallel to the rail  24   a  and the slider  25  is fixed thereto in a manner similar to the fixing of the carriage  11  to the belt  14 .  
         [0026]    The operation of the apparatus is described hereinafter assuming that the apparatus is in the position assumed at the end of an operating cycle shown in FIG. 2. In this position, the locking bar  18  is kept spaced from the length of textile material  2 , which by being fed by the grip unit formed by rollers  4  and  5  can slide between the profiled elements  17   a  and  17   b  and the bar  18 . The strip  23  is turned vertically downward and the sewing machine  26  is in stand by at one end of the rail  24 .  
         [0027]    While the initial end of the length of textile material  2  is gripped between the rollers  4  and  5 , the motor  8  is activated (see FIG. 4) and, by actuating the rollers  4  and  5  so that they rotate in opposite directions, causes the unwinding of the length of material  2  by a preset extent. The portion of the length of material  2  which, due to the traction produced by the rollers  4  and  5 , is unwound from the roll  1 , after passing between the profiled elements  17   a  and  17   b  and the abutment bar  18 , arranges itself between the strip  23  and the bar  21 . The portion of the length of material  2  that is unwound in each instance from the roll  1  has such a longitudinal dimension that its leading edge  31  protrudes slightly below the edge of the strip  23 .  
         [0028]    At this point, the cylinders  24  are activated, turning the strip  23  horizontally below the tabs  22  (see FIG. 5) so as to block the front transverse margin  32  of the length of material  2  so that its leading edge  31 , by protruding forward from the tabs  22  and from the strip  23 , is now positioned on the line of advancement of the needle of the sewing machine  26 .  
         [0029]    By activating the motor  27 , the sewing machine  26  is made to advance along the rail  24   a  so as to sew the leading edge  31 . Once sewing has been completed, the cylinders  24  are actuated, returning the strip  23  to the vertical position (see FIG. 6).  
         [0030]    In the subsequent step (see FIG. 7), the rollers  4  and  5  of the assembly  3  are activated again, unwinding from the roll  1  a portion of the length of material whose longitudinal dimension corresponds to the longitudinal dimension of the piece  33  to be obtained.  
         [0031]    Then the pneumatic cylinders  19  and  20  are activated, causing the advancement of the bar  18  until the edges of the wings  18   a  and  18   b  that delimit the gap  18   c  abut against the profiled elements  17   a  and  17   b , thus locking the length of textile material  2 . Once the length of material  2  has been clamped, the electric motor  16  is activated and causes the advancement of the carriage  11  and therefore of the cutting assembly mounted thereon. In this manner, the rotating blade  13 , by advancing along the gaps  17   c  and  18   c  transversely to the unwinding direction A, cuts from the length of textile material  2  a piece  33  whose longitudinal dimension is equal to the longitudinal dimension between the edge  31  and the gap  18 .  
         [0032]    The operating cycle is then repeated in the manner described above.  
         [0033]    It is evident that the described apparatus allows to work on individual pieces obtained from a continuous length of textile material wound on a roll. This ensures that the various layers that compose the piece, once the cutting of the length of material has been completed, cannot arrange themselves out of place during the handling to which they are subjected in order to be prepared for successive treatments such as bordering, quilting and so forth. If the tubular part is constituted by a tubular article, the stitched seam closes the leading edge and forms a pouch that can be used to cover mattresses or the like.  
         [0034]    In the practical embodiment of the invention, numerous modifications and variations are possible all within the scope of the same inventive concept.  
         [0035]    In a second embodiment of the invention, the tabs  22  for elastic retention of the margin  23  of the length of textile material are obtained by cutting notches  34  into a metal plate as shown in FIG. 8.  
         [0036]    In a third embodiment of the invention (see FIGS.  9 - 13 ), the bar  21  is articulated about an axis  35  located at a higher level than the axis  36  of the strip  23 . A metal plate  37  is rigidly coupled to the bar  21 , instead of the tabs  22 , and in the inactive position arranges itself by gravity parallel to the strip  23  at a distance that is greater than the thickness of the length of textile material  2 . The height of the metal plate  37  is such that its free edge  38  is arranged at an intermediate level of the strip  23 .  
         [0037]    By way of the distance between the walls of the metal plate  37  and of the strip  23 , when said strip is turned so as to tilt horizontally the margin  32 , said margin is locked by the edge  38  against the strip  23 . As the rotation of the strip  23  continues, the axial offset of the axes  35  and  36  causes a sliding of the edge  38  on the strip  23  and the gradual expulsion of the margins  32  beyond the edge of the strip  23 .  
         [0038]    Once the strip  23  has reached the horizontal position, the edge  31  of the margin  32  is aligned with the sewing path of the sewing machine  26 .  
         [0039]    The disclosures in Italian Patent Application No. BO2000A000716 from which this application claims priority are incorporated herein by reference.
An apparatus for sewing finishing a piece cut from a length of textile material unwound from a roll and closing the leading edge thereof, comprising: advancement rollers for advancement of the length of textile material, to unwind two successive portions of the length of material, for a total longitudinal extension equal to the longitudinal extension of the piece; a cutting blade suitable to cut a piece from the length of textile material with a cut that is perpendicular to the unwinding direction and forms the rear edge of the cut piece and the leading edge of the length of textile material to be unwound; and positioning elements for arranging the leading edge of the unwound length of material with respect to a sewing machine.