Abstract:
The needle board for use in a needling machine for needling a flat textile material comprises first needle rows and second needle rows, wherein the first needle rows and the second needle rows are arranged inclined with respect to a longitudinal direction of the needle board, which longitudinal direction corresponds to a direction in which the flat textile material to be needled is conveyed in the needling machine. The first needle rows are arranged at a first angle to the longitudinal direction, and the second needle rows are arranged at a second angle to the longitudinal direction. An absolute value of the second angle is different from an absolute value of the first angle.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority based on European patent application EP 15 193 390.0 filed Nov. 6, 2015. The entire disclosure and contents of this application is incorporated by reference into the present application. 
       FIELD 
       [0002]    The present invention relates to a needle board, and more particularly, to a needle board for use in a needling machine for needling a flat textile material such as a nonwoven, a woven fabric or a laid material. 
       BACKGROUND 
       [0003]    When flat textile materials are needled, especially nonwovens, it is desirable to achieve the most uniform possible needling without the formation of patterns in the flat textile material. 
         [0004]    It has been found advantageous for this purpose for rows of needles to be arranged in a herringbone pattern and not simply to extend in rows and columns in the longitudinal and transverse directions of the needle board. Nevertheless, stripes or patternings still occur in the needled flat textile material, especially at high feed-per-stroke ratios. 
         [0005]    It is an object of the present invention to provide a needle board for use in a needling machine for needling a flat textile material of which a uniformly needled flat textile material is obtained even at high feed-per-stroke ratios or over a wider feed range of the needling machine. 
       SUMMARY 
       [0006]    According to an aspect of the invention, the needle board for use in a needling machine for needling a flat textile material comprises first needle rows and second needle rows, wherein the first needle rows and the second needle rows are arranged inclined with respect to a longitudinal direction of the needle board, which longitudinal direction corresponds to a direction in which the flat textile material to be needled is conveyed in the needling machine. The first needle rows are arranged at a first angle to the longitudinal direction, wherein the second needle rows are arranged at a second angle to the longitudinal direction. An absolute value of the second angle is different from an absolute value of the first angle. 
         [0007]    Through variation of the absolute values of the angles and the nonuniform distribution of the needles in the needle board thus achieved, the formation of patternings in the needled flat material can be prevented even at high conveying speeds of the flat textile material through the needling machine in the great majority of cases. This is highly preferable. 
         [0008]    Preferably, the first needle rows are arranged in a first block, and the first needle rows of the first block are parallel to each other. Further, preferably the second needle rows are arranged in a second block, wherein the second needle rows of the second block are parallel to each other. 
         [0009]    It is also preferable to promote the further homogenization of the stitching pattern in the needled flat textile material, the needle board comprises a plurality of first blocks and a plurality of second blocks, wherein the first blocks and the second blocks are arranged to form a herringbone pattern. 
         [0010]    An especially homogeneous stitching pattern is preferably obtained when the first needle rows and the second needle rows are arranged in such a way that a first projection of the first needle rows and of the second needle rows in or opposite to the longitudinal direction of the needle board yields at least certain sections in a transverse direction of the needle board, the transverse direction being perpendicular to the longitudinal direction of the needle board, in which sections transverse distances between first individual needle projections are equal. 
         [0011]    It is highly preferred that to obtain a satisfactory stitching density, the transverse distances between the first individual needle projections are in the range of 0.05-2.5 mm, preferably of 0.1-1.5 mm, and more preferably of 0.2-1.0 mm. 
         [0012]    Furthermore, preferably the first needle rows and the second needle rows are arranged in such a way that a second projection of the first needle rows and of the second needle rows in a transverse direction of the needle board, the transverse direction being perpendicular to the longitudinal direction of the needle board, yields at least certain sections in the longitudinal direction of the needle board, where longitudinal distances between second individual needle projections are different. 
         [0013]    Preferably, when the needles in all of the first and second needle rows are spaced equally apart, this result is obtained automatically, thanks to the different absolute values selected for the first and second angles of the needle rows to the longitudinal direction of the needle board. All of the needle rows of a block of needle rows are usually arranged next to each other in such a way that the same needles of each needle row, i.e., all of the needles in the first position, all of the needles in the second position etc., together form a line extending in the transverse direction. From this follows in turn that the transverse projections of the needles within a block of needle rows comprise the same longitudinal distances from each other. 
         [0014]    The transverse projections of the needles within a first block of first needle rows comprise first longitudinal distances from each other in the range of 0.5-20 mm, preferably of 1.0-15 mm, and more preferably of 2.0-5.0 mm. 
         [0015]    The transverse projections of the needles within a second block of second needle rows comprise second longitudinal distances to each other in the range of 0.3-15 mm, preferably of 0.7-10 mm, and more preferably of 1.5-4.0 mm. 
         [0016]    It has been found to be especially preferable for the absolute value of the first angle of the first needle rows to the longitudinal direction of the needle board to be in the range of 10-30°, preferably of 15-25°, and more preferably of 17-23°. 
         [0017]    It has also been found preferable and advantageous for the absolute value of the second angle of the second needle rows to the longitudinal direction of the needle board to be in the range of 25-65°, preferably of 30-60°, and more preferably of 42-48°. 
         [0018]    A needle row usually preferably comprises 5-40 needles. In a preferred embodiment, the needles of each needle row are connected to each other and thus form a needle module, which is arranged in a slot in the needle board. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]    The invention is explained in greater detail below with reference to the embodiments illustrated in the drawings: 
           [0020]      FIG. 1  is a top view of part of an embodiment of a needle board according to the invention; and 
           [0021]      FIG. 2  is a top view of the detail marked “X” in  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION 
       [0022]      FIG. 1  shows a top view of an embodiment of the needle board according to the invention. The individual needles  2  of the needle board are arranged in first needle rows  6  and second needle rows  7  and are indicated in this top view ( FIG. 1 ) as dots. The tips of these needles  2  project into the plane of the drawing beyond the base body  4  of the needle board. In the embodiment shown, each first or second needle row  6 ,  7  comprises approximately 20 needles. A needle row  6 ,  7  usually comprises between 5 and 40 needles. 
         [0023]    The expert is familiar with many different possible ways in which needles  2  can be attached to base body  4  of the needle board. These ways include in particular the insertion of individual needles  2  into individual bores in base body  4  of the needle board. It is also possible, as shown in  FIG. 1 , for individual needles  2  of a first or second needle row  6 ,  7  to be connected to each other to form a needle module  8 , which in turn is inserted as a unit into a slot  10  in base body  4  of the needle board. First and second needle rows  6 ,  7  are formed in both of these cases. 
         [0024]    First and second needle rows  6 ,  7  are preferably arranged in first and second blocks  12 ,  13 . Needle rows  6 ,  7  are in turn arranged to form a herringbone pattern extending in the longitudinal direction L of the needle board. This is understood to mean an arrangement in which needle rows  6 ,  7  are arranged inclined with respect to longitudinal direction L of the needle board, in such a way that the angle of all needle rows  6 ,  7  of one block  12 ,  13  to longitudinal direction L of the needle board has a certain sign (+ or −), and the angle of all of first or second needle rows  6 ,  7  of a first or second block  12 ,  13  adjacent thereto in longitudinal direction L has the opposite sign. Often successive needle rows  6 ,  7  have the same absolute value for this angle, as a result of which a homogeneous herringbone pattern can be formed in parts of the needle board. 
         [0025]    In the needle board shown in  FIG. 1 , a distinction is made between first needle rows  6 , which are combined into first blocks  12 , and second needle rows  7 , which are combined into second blocks  13 . It is clear from  FIG. 1  that all of first or second needle rows  6 ,  7  of a specific first or second block  12 ,  13  are parallel to each other. In addition, the needles of first or second needle rows  6 ,  7  of a first or second block  12 ,  13  should ideally have the same spacing in the direction in which first or second needle rows  6 ,  7  extend, and, considered in longitudinal direction L of the needle board, first or second needle rows  6 ,  7  should begin and end at the same length, i.e., begin and end at points such that the rows are all of equal length. In the transverse direction Q of the needle board, first and second blocks  12 ,  13  can extend over the entire width of the needle board or over only parts of it. 
         [0026]    In the following, the first and second angles α, β are always to be understood as the smaller of the two angles of intersection of a first or second needle row  6 ,  7  with a straight line extending in longitudinal direction L of the needle board. The absolute value of second angle β of second needle rows  7  to longitudinal direction L of the needle board is different from the absolute value of first angle α of first needle rows  6  to longitudinal direction L of the needle board. The absolute value of first angle α of first needle rows  6  to longitudinal direction L of the needle board is in the range of 10-30°, preferably of 15-25°, and even more preferably of 17-23°. The absolute value of second angle β of second needle rows  7  to longitudinal direction L of the needle board is in the range of 25-65°, preferably of 30-60°, and even more preferably of 42-48°. 
         [0027]    First and second needle rows  6 ,  7  are arranged in such a way that a projection  14  of first and second needle rows  6 ,  7  in the transverse direction Q of the needle board, i.e., the direction perpendicular to the longitudinal direction of the needle board, yields at least certain sections in longitudinal direction L of the needle board where the longitudinal distances L 1 , L 2  between the projections  16  of the individual needles are different. Projections  16  of the needles within a block  12 ,  13  of needle rows  6 ,  7  comprise the same longitudinal distances L 1 , L 2  from each other. 
         [0028]    In the present application, needle projections  16  within a first block  12  of first needle rows  6  are separated from each other by longitudinal distance L 1 , whereas needle projections  16  within a second block  13  of second needle rows  7  are separated from each other by longitudinal distance L 2 . Longitudinal distance L 1  separating needle projections  16  within a first block  12  of first needle rows  6  is in the range of 0.5-20 mm, preferably of 1.0-15 mm, and even more preferably of 2.0-5.0 mm. Longitudinal distance L 2  separating needle projections  16  within a second block  13  of second needle rows  7  is in the range of 0.3-15 mm, preferably of 0.7-10 mm, and even more preferably of 1.5-4.0 mm. 
         [0029]    It is especially preferable for needle rows  6 ,  7  to be arranged in such a way that a projection  18  of needle rows  6 ,  7  in or opposite to longitudinal direction L of the needle board yields at least certain sections in the transverse direction Q of the needle board, preferably large areas or the entire area, where the transverse distances T between individual needle projections  20  are equal. This is best seen in the enlarged diagram of the detail “X” in  FIG. 2 . The transverse distances T between individual needle projections  20  are in the range of 0.05-2.5 mm, preferably of 0.1-1.5 mm, and even more preferably of 0.2-1.0 mm. 
         [0030]    It should be clear that the configuration of the needle board can be modified in many ways. This pertains to the number of needles  2  in each first and second needle row  6 ,  7 , as well as to angles α and β of needle rows  6 ,  7  to longitudinal direction L of the needle board, to the number of first and second needle rows  6 ,  7  within a first or second block  12 ,  13 , to the spacing of individual needles  2  from each other within a first or second needle row  6 ,  7 , and also to the distances between individual blocks  12 ,  13  or first and second needle rows  6 ,  7 . It is also conceivable that the individual needles could be spaced apart in different ways within a needle row  6 ,  7 . 
         [0031]    The number of first and second blocks  12 ,  13  is also variable as is their arrangement with respect to each other. Five blocks  12 ,  13  are shown in  FIG. 1 , i.e., three first blocks  12  of first needle rows  6  and two second blocks  13  of second needle rows  7 . First blocks  12  of first needle rows  6  are arranged one after the other, as are also second blocks  13  of second needle rows  7 . It would also be conceivable that first and second blocks  12 ,  13  of first and second needle rows  6 ,  7  could be arranged in alternating fashion or in any other desired sequence. 
         [0032]    Finally, first and second needle rows  6 ,  7  of first and second blocks  12 ,  13  in  FIG. 1  are arranged to form a herringbone pattern extending in longitudinal direction L of the needle board. It would also be conceivable that angled first and second needle rows  6 ,  7  could be arranged differently, e.g., two or more successive first or second blocks  12 ,  13  at a positive angle to longitudinal direction L and at least one other first or second block  12 ,  13  at a negative angle to longitudinal direction L or vice versa. 
         [0033]    The invention has been described so far on the basis of first and second blocks  12 ,  13  of first and second needle rows  6 ,  7  arranged to form a herringbone pattern. First and second needle rows  6 ,  7  could also be arranged next to each other in such a way as to form a herringbone pattern without forming first and second blocks  12 ,  13 . 
         [0034]    A wide variety of materials are available for the various parts discussed and illustrated herein. While the principles of this device have been described in connection with specific embodiments, it should be understood clearly that these descriptions are made only by way of example and are not intended to limit the scope of the device.