Patent Publication Number: US-11643765-B2

Title: Control device for controlling the movement of the needles of a needleloom, notably of an elliptical needleloom, and needle loom comprising such a device

Description:
TECHNICAL FIELD 
     The present invention relates to a movement control system monitoring the path of the needles of a needling machine, in particular the component in the direction MD of movement in an elliptical path of the needles of a needling machine with elliptical movement, and a needling machine, in particular elliptical, comprising a control system of this type. 
     BACKGROUND 
     Classically, an elliptical needling machine to consolidate a fleece or web of fibres, in particular non-woven by needling, comprises at least one needle plate, in front of which the fleece or web of fibres passes in the direction of advance or machine or MD direction, and driving systems configured to impart to at least one needle plate and/or needles a to and fro motion perpendicular, or essentially perpendicular, to the plane of the fleece or web so that the needles cross the fleece or web of fibres first in one direction, then the other, in an elliptical path. 
     To impart to the plate or needles for example an elliptical motion, MD drive systems are fitted configured to impart to the needles and/or needle plate the MD component of their elliptical motion. 
     Known MD drive systems are of complex structure and occupy a lot of space. It would be desirable to have a drive system available with a more simple structure that can, in particular, be adjusted while running or when stopped. In addition, in some cases, it would be desirable to locate the MD drive systems in a sealed housing, alongside the drive system for the plates in the longitudinal direction, and a more compact structure is being sought to achieve that. 
     SUMMARY OF THE INVENTION 
     According to the invention, a control system for the component in a given direction, for example the MD direction, of motion in a given path, for example elliptical, of the needles of a needling machine, for example an elliptical needling machine, designed to consolidate a fleece or web of fibres, in particular non-woven, by needling, comprising at least one needle plate with an array of needles and drive systems configured to impart a to and fro motion to the at least one needle plate and or needles so that the needles follow a given path, for example elliptical, to cross in one direction, then the other, the fleece or web of fibres that is moved in front of them in the machine or drive direction MD to consolidate it, the control system being as defined in claim  1 . 
     According to a favoured method of implementation, the said one direction given above is the MD direction and the said given path is elliptical, the drive system comprises an MD drive system configured to impart to the at least one plate and/or the needles the MD component of their elliptical motion. 
     According to another favoured method of implementation, the said one given direction is the vertical direction and the said one given path is straight. The motion of the needles being to and fro in the vertical direction. 
     Beneficial improvements and methods of implementation are defined in the claims below. 
     The present invention also relates to a needling machine, in particular elliptical, comprising a control system according to the invention. 
     In particular, the needling machine comprises one or more columns to which one of the respective needle plates is or are connected, in particular oscillating, longitudinal drive systems being fitted to impart to each column a to and fro motion parallel to the longitudinal axis of the column, at least part of each column and the longitudinal drive system being enclosed in a sealed housing, in which the MD control system is also enclosed. 
     According to the invention, a less complex system than those of the prior art is thus obtained, in particular from a mechanical point of view, which is also more compact. In particular, it is no longer necessary to provide phase shifting between two cam shafts. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       As an example, preferred methods of implementation of the invention are now described with reference to the drawings in which: 
         FIG.  1    is a front view of the assembly partly in cross section and cut away, of a needling machine comprising a control system according to a method of implementation of the invention; 
         FIG.  1 A  is a larger scale view of part of  FIG.  1   ; 
         FIG.  2    is a front view of the assembly partly in cross section and cut away, is a front view of the assembly partly in cross section and cut away comprising a control system according to a method of implementation of the invention; 
         FIG.  2 A  is a front view of the assembly partly in cross section and cut away, of a needling machine according to yet another method of implementation according to the invention; 
         FIG.  3    is a front view of the assembly partly in cross section, of yet another needling machine comprising a control system according to a method of implementation of the invention; 
         FIG.  4    is a front view of the assembly partly in cross section, of yet another needling machine comprising a control system according to a method of implementation of the invention; 
         FIG.  5    is a perspective view of a method of implementation of a control system according to the invention; 
         FIG.  5 A  is a perspective view of another method of implementation of a control system according to the invention; 
         FIG.  5 B  is a perspective view of yet another method of implementation of a control system according to the invention; 
         FIG.  6 A  is a view of the assembly in another method of implementation of a control system according to the invention; 
         FIG.  6 B  is a rear view of the control system in  FIG.  6 A ; and 
         FIG.  7    is a view of the assembly of yet another method of implementation of a control system according to the invention; 
         FIG.  8    is a front view of the assembly partly in cross section, of a needling machine comprising a control system according to the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG.  1    shows a first method of implementation of a needling machine according to the invention. The housing is shown in cross section and the rest of the needling machine in front view, part of the guide pot being cut away. 
     This needling machine comprises a needle plate  10  comprising needles  1  projecting from the lower face of the plate and arranged either in rows and columns, or randomly, or pseudo-randomly, as is well known in the field. The needle plate  10  is carried by a beam  2 , called a moving beam. The beams  2  and plate  10  are connected rigidly together, but removable, to enable a plate to be easily replaced with a new plate when the needles are worn and/or broken. The needles are designed to have an elliptical to and fro motion from top to bottom and from bottom to top to cross in one direction, then the other, a fleece or web of fibres passing before them in the drive or MD direction, that is left to right horizontally in the diagram. 
     A longitudinal column  3  extending in a longitudinal axis  11  perpendicular to the plane of the plate connected rigidly to the moving beam  2 , so that the motions of column  3 , the moving beam  2 , the needle plate  10  and the needles are the same, that is with the same elliptical path. 
     Drive systems are fitted to impart to the column  3  (and therefore also the needle plate  10 , the moving beam  2  and the needles  1 ) a motion with a component parallel to the longitudinal axis  11  and a component in the MD direction, so that it follows an elliptical path as shown in  FIG.  1    by an ellipse for the needles. 
     A sealed housing  7  encloses the drive systems and part of the column  3 , the latter passing through the wall of the housing  7  and a guide pot  4  whose interface with the housing  7  is made oil-tight by means of a seal which according to a possible method of implementation may take the form of an expansion joint  50 . The guide pot  4  oscillates in relation to a pin  5  fixed in relation to the housing  7 , parallel to the direction CD (perpendicular to the direction MD and the longitudinal axis  11 ). The column  3  can slide inside the guide pot  4 . Guide bushes  16  are fitted in the wall of the guide pot  4 , to ensure sliding and lubrication between the column  3  and the guide pot  4 . Oil-tightness between the column  3  and the guide pot  4  is ensured by a seal (not shown) fixed to the base of the guide pot. 
     In a highly favoured manner, in particular in terms of long life and oil-tightness of the housing, the fixed pin  5  is located essentially at the level of the opening in the housing passed through by the guide pot  4 , in particular in the opening. 
     The drive systems comprise first longitudinal drive systems configured to impart a to and fro motion to the column parallel to the longitudinal axis. The first drive systems consist of two systems  6  with cam shafts  12  and rods  13  and an intermediate tie-rod  9 . 
     The shafts  12  rotate the heads of the two tie-rods  13  (as shown by the two arrows at the top of  FIG.  1   ) in opposite directions. The feet  14  of the two tie-rods  13  are each hinged at one end of the intermediate tie-rod  9  which extends in the MD direction. The intermediate tie-rod  9  also comprises a leg  15  projecting centrally downwards. The end of the leg  15  is hinged to the upper end of the column  3 . 
     The first longitudinal drive systems impart to the column  3  a solely longitudinal to and fro motion. 
     A second transverse drive system in the form of a main tie-rod  8  fitted in the MD direction is also fitted. One end of the tie-rod  8  is hinged to the guide pot  4 , inside the housing  7 , at a point  17  at a distance from the axis of rotation  5  of the pot, in particular essentially at the upper end of the pot. An oscillatory to and fro motion is thus imparted to the guide pot  4  which is transferred to the column  3  which passes though it with a to and fro motion in the MD direction, or essentially in the direction MD (as shown by the double arrow above the tie-rod  8  in  FIG.  1   ). The other end of the tie-rod  8  is coupled to a control system, called the advance system, which can be any one of those shown below in  FIGS.  5 ,  6 A,  6 B and  7   . 
     Secondly, a system balance weight  19  is coupled to the guide pot  4 , fixed to the latter on the side opposite the advance system. 
     Finally, the advance system being enclosed in the sealed housing, it can be driven either by an independent motor, or by one of the control shafts  6  of the first vertical drive system, or by a rod mounted directly on a cam shaft rigidly connected to one of the control shafts  6  of the first drive system. 
       FIG.  2    shows another method of implementation of a needling machine according to the invention. The housing is shown in cross section and the rest of the needling machine in front view, part of one guide pot being cut away. 
     This needling machine comprises two needle plates  10 ′ comprising needles  1 ′ projecting from the lower face of the plate arranged either in rows and columns, or randomly, or pseudo-randomly, as is well known in the field. Each needle plate  10 ′ is carried by a respective beam  2 ′, called the moving beam. The needles are designed to have an elliptical to and fro motion from top to bottom and from bottom to top, crossing in one direction, then the other, a fleece or web of fibres passed before it in the drive or MD direction, that is left to right horizontally in the diagram. 
     Two longitudinal columns  3 ′ extend with longitudinal axes  11 ′ perpendicular to the plane of the plate. The columns  3 ′ are each connected rigidly to a moving beam  2 ′, so that the motions of the column  3 ′, the moving beam  2 ′, the needle plate  10 ′ and the needles are the same, that is with the same elliptical path. 
     Drive systems are fitted to impart to each column  3 ′ (and therefore also to the needle plates  10 ′, the moving beams  2 ′ and the needles  1 ) a motion with a component parallel to the longitudinal axis  11 ′ and a component in the MD direction, to give an elliptical path as shown in  FIG.  2    by an ellipse for the needles. 
     A sealed housing  7 ′ encloses the drive systems and part of the columns  3 ′, which pass through the wall of the housing  7 ′ through respective guide pots  4 ′, whose interfaces with the housing  7 ′ are made oil-tight by means of seals (not shown), but that, for example, may be in the form of expansion joints as shown in  FIG.  1 A ). Each guide pot  4 ′ oscillates about a pin  5 ′, fixed in relation to the housing  7 ′ and parallel to the direction CD (perpendicular to the direction MD and the longitudinal axis  11 ′). Each column  3 ′ can slide within the respective guide pot  4 ′. Guide bushes  16 ′ are fitted to the internal wall of each guide pot  4 ′ to ensure sliding and lubrication between the column  3 ′ and the respective guide pot  4 ′. Sealing between the column  3 ′ and the respective guide  4 ′ is by means of a seal (not shown) fixed to the base of the guide pot. 
     The drive systems comprise first longitudinal drive systems configured to impart a to and fro motion to each column parallel to the longitudinal axis. The first drive systems consist of two shaft systems  6 ′ with cams  12 ′ and tie-rods  13 ′. 
     The drive shafts  12 ′ drive the heads of the two tie-rods  13 ′ that rotate in opposite directions (as shown by the two arrows at the top of  FIG.  1   ). The feet  14 ′ of the two tie-rods  13 ′ are each hinged at one end of a respective column  3 ′. 
     The first longitudinal vertical drive systems impart to each column  3 ′ a to and fro motion essentially parallel to the longitudinal axis. 
     Second transverse drive systems are also fitted in the form of a main tie-rod  8 ′ and an auxiliary tie-rod  9 ′ fitted in the direction MD inside the housing  7 ′. One end of the tie-rod  8 ′ is hinged to one of the guide pots  4 ′ at a point  17 ′ at a distance from the axis  5 ′ of rotation of the pot, in particular essentially at the upper end of the pot. The other end of the tie-rod  8 ′ is coupled to a control system, called the advance system, which is any one of those shown below in  FIGS.  5 ,  6 A,  6 B and  7   . 
     The auxiliary tie-rod  9 ′ is hinged at its two opposite ends to one of the respective pots  4 ′. In particular, the tie-rod  9 ′ is also hinged to the end of the tie-rod  8 ′ at the point  17 ′. 
     A to and fro oscillatory motion is thus imparted to the two guide pots  4 ′ that is transferred to the columns  3 ′ which pass through them with a to and fro motion in the direction MD, or essentially in the direction MD (s shown by the double arrow above the tie-rod  8 ′ in  FIG.  2   ). 
     Secondly, a system balance weight  19 ′ is coupled to the auxiliary tie-rod  9 ′, being fixed to the latter on the upper side half way between the two shafts  12 ′. 
     Finally, as the advance system is enclosed in the sealed housing, it can be actuated either by an independent motor, or by one of the control shafts  12 ′ of the first vertical drive system, or by a rod mounted directly on a cam rigidly connected to one of the control shafts  12 ′ of the first drive system. 
     In particular, as shown in  FIG.  2 A , which shows a variant of the method of implementation in  FIG.  2   , but which can also be applied to the method of implementation in  FIG.  1   , a mechanical linkage is fitted between the main tie-rod  8 ′ and a transverse drive rod  51  driven by the cam shaft  12 ′ of one of the two rod and cam shaft systems  6 ′, for example, as shown in  FIG.  2 A , by the cam shaft  12 ′ that also drives the rod  13 ′ hinged to the pot  4 ′ also directly connected to the tie-rod  8 ′. In this variant of  FIG.  2 A , an intermediate lever  52  is fitted that can rotate about a pin  53  fixed in relation to the housing  7 ′ and hinged directly at both ends to the rod  51  and the main tie-rod  8 ′. 
     In the above description, the first longitudinal drive systems are different from the second transverse drive system. Although this separation into two distinct drive systems has advantages, single drive systems however could be fitted that perform the two functions of first and second drive systems, while remaining within the scope of the invention as defined by the claims. 
       FIG.  3    shows yet another method of implementation of a needling machine comprising a control system according to the invention. The housing is shown in cross section, while the rest of the needling machine is shown in front view. 
     This needling machine comprises two needle plates  10 ″ comprising needles  1 ″ projecting from the lower face of their respective plate and arranged either in rows and columns or randomly or, pseudo-randomly, as is well known in the field. Each needle plate  10 ″ is carried by a beam  2 ″, called the moving beam. The beam  2 ″ and the respective plate  10 ″ are rigidly connected to each other, but removable so that when the needles are worn and/or broken, a plate can be easily replaced with a new plate. The needles are designed to have an elliptical to and fro motion from top to bottom and from bottom to top so that they pass first in one direction then the other through a fleece or web of fibres passed before them in the drive or MD direction, that is from left to right horizontally in the diagram. 
     Two longitudinal columns  3 ″ extending with a longitudinal, vertical axis  11 ″ perpendicular to the plane of the plate are each linked to a respective moving beam  2 ″ by means of two respective intermediate vertical tie-rods  9 . 
     Each vertical tie-rod  9 ″ is hinged firstly, at its upper end to the lower end of one respective column  3 ″ and secondly, at its lower end to a point  17 ″ on the upper part of a respective moving beam  2 ″ mobile. 
     First longitudinal drive systems are fitted to impart to each column  3 ″ a straight to and fro motion parallel to the longitudinal axis  11 ″ which remains vertical throughout the motion. 
     A sealed housing  7 ″ encloses the first drive system and part of each column  3 ″, the latter passing through the wall of the housing  7 ″ through respective guide pots  4 ″. Each guide pot  4 ″ is fixed in relation to the housing. Each column  3 ″ slides within the respective guide pot  4 ″ during its vertical to and fro motion. Guide bushes  18 ″ are fitted inside the guide pot  4 ″ to ensure sliding and lubrication between the column  3 ″ and the guide pot  4 ″. The interface between the column  3 ″ and the guide pot  4 ″ is made oil-tight by means of a seal (not shown) fixed to the base of the guide pot. 
     The first longitudinal drive systems consist of two cam shaft systems  6 ″ whose shafts drive the heads of two tie-rods that rotate at the same speed in opposite directions. The feet of the two tie-rods are hinged to a respective column. 
     These first longitudinal, vertical drive systems impart a solely to and fro motion in the longitudinal, vertical axis to each column  3 ″. 
     Second transverse drive systems in the form of a main tie-rod  8 ″ in the direction MD are also fitted. One end of the tie-rod  8 ″ is hinged to the vertical tie-rod at the hinge point  17 ″ of the upper part of one of the moving beams  2 ″. A to and fro motion in the direction MD, or essentially in the direction MD (as shown by the double arrow above the tie-rod  8 ″ in  FIG.  3   ) is thus imparted to this moving beam  2 ″ The other end of the tie-rod  8 ″ is coupled to a control system, called the advance system, which may, in particular, be like those shown below in  FIGS.  5  to  7   . In addition, an auxiliary tie-rod  20 ″ is hinged firstly to the end of the main tie-rod  8 ″, in particular at the point  17 ″ on the moving beam  2 ″, and secondly to the other moving part, therefore also transmitting the to and fro motion in the direction MD to the latter. 
       FIG.  4    shows another method of implementation of a needling machine according to the invention. The housing is shown in cross section, while the rest of the needling machine is shown in front view. 
     This needling machine comprises a needle plate  10 ′″ fitted with needles  1 ′″ projecting from the lower face of their respective plate, being arranged either in rows and columns, or randomly, or pseudo-randomly, as is well known in the field. The needle plate  10 ′″ is carried by a beam  2 ′″, called the moving beam. The beam  2 ′″ and plate  10 ′″ are connected rigidly together removably, so that when the needles are worn and/or broken, a plate can easily be replaced with a new plate. The needles are designed to have an elliptical to and fro motion from top to bottom and from bottom to top in one direction then the other, over a fleece or web of fibres passed before them in the drive or MD direction, that is left to right horizontally in the diagram. 
     A longitudinal column  3 ′″, extending in a longitudinal vertical axis  11 ′″ perpendicular to the plane of the plate, is linked to the moving beam  2 ′″ with an intermediate vertical tie-rod  9 ″. 
     The vertical tie-rod  9 ′″ is hinged firstly, at its upper end to the lower end of the column  3 ′″ and secondly, at its lower end to a point  17 ″&#39; on the upper part of the moving beam  2 ″. 
     First longitudinal drive systems are fitted to impart to the column  3 ′″ a straight to and fro motion parallel to the longitudinal axis  11 ″&#39;, which remains vertical throughout the motion. 
     A sealed housing  7 ′″ encloses the first drive systems and part of the column  3 ′″, the latter passing through the wall of the housing  7 ′″ through a respective guide pot  4 ″. The guide pot  4 ′″ is fixed in relation to the housing. During its to and fro vertical motion, the column slides within the guide pot  4 ″. Guide bushes  18 ″&#39; are fitted in the wall inside each guide pot  4 ′″, to ensure sliding and lubrication between the column  3 ′″ and the respective guide pot  4 ″. The interface between the column  3 ′″ and the guide pot  4 ′″ is made oil-tight with a seal (not shown) fixed to the base of the guide pot. 
     The first longitudinal drive systems consist of two cam shaft systems  6 ′″ whose shafts drive the heads of two tie-rods rotating at the same speed in opposite directions. The feet of the two tie-rods are hinged to the respective lateral arms of a T-shaped tie-rod  19 ″′, while the main arm or stem of the T-shaped tie-rod is hinged to the column  3 ″. These first longitudinal, vertical drive systems impart a solely to and fro motion in the vertical longitudinal axis to the column  3 ′″. 
     Second transverse drive systems are also fitted in the form of a main a tie-rod  8 ′″ fitted in the direction MD. One end of the tie-rod  8 ′″ is hinged to the hinge point  17 ′″ on the upper part of the moving beam  2 ′″ to the vertical tie-rod. A to and fro motion in the direction MD, or essentially in the direction MD (as shown by the double arrow above the tie-rod  8 ′″ in  FIG.  4    is therefore imparted to this moving beam  2 ″). The other end of the tie-rod  8 ′″ is coupled to a control system, called the advance system, which can, in particular, be like those shown below in  FIGS.  5  to  7   . 
       FIGS.  5 ,  6 A,  6 B and  7    show methods of implementation of the control system of the to and fro motion in the direction MD of the tie-rods  8 ,  8 ′,  8 ″ and  8 ′″, respectively of the methods of implementation in  FIGS.  1 ,  2 ,  3  and  4   . 
     In  FIG.  5   , the system comprises a cam shaft  21  coupled to a rod  22  hinged directly to a one piece (or possibly consisting of several parts hinged together) vertical lever  23  that pivots vertically in relation to a fixed offset pivot pin  24  below the articulation axis of the rod  22  to the lever  23 . A tie-rod  27  is coupled directly to the lever  23 . The tie-rod  27  is rigidly connected to a slider  25  and one end of a pin  26  whose axis is parallel to the pin  24 . 
     The relative position of the rod pin  26 , and therefore also of the tie-rod  27 , in relation to the pivot pin  24  of the lever in the vertical direction and/or in relation to the hinge pin of the rod  22  to the lever can be adjusted by means of an adjustment system consisting of an auxiliary adjustment cam shaft  29  and an adjustment tie-rod  28 . The adjustment tie-rod  28  is hinged at its upper end to the cam shaft (or crankshaft)  29 , while its lower end can pivot in relation to the pin of the pin  26 . 
     The lever comprises an opening in the form of a slot  30 , in which the slider  25  slides together with translation of the pin  26 . 
     Depending on the position of the connecting rod  28  which is determined by an appropriate rotation of the crank wheel  29 , the relative position of the slider  25  in the slot  30  can be chosen and adjusted to adjust the distance in the vertical axis of the lever between the pin  24  and an axis of the pin  26  (and therefore also the distance between the axis of the pin  26  and the pin of the rod  22 ), this distance can be varied between zero (the position of the slider  25  at the top of the slot  30  so that the axis of the pin  26  corresponds with the pin  24  and the maximum adjustment position, in which the slider  25  is right at the bottom of the slot  30 ). 
     The amplitude of the to and fro motion of the connecting rod  27  can be varied either while running or at rest, the motion repeated from the motion of the crankshaft  21  and the tie-rod  22  acting on the lever  23 . Regarding the tie-rod  27 , this can be rigidly connected or hinged to any of the tie-rods  8 ,  8 ′ and  8 ″ in the methods of implementation in  FIGS.  1 ,  2  and  3   . 
       FIG.  5 A  shows a variant of the arrangement in  FIG.  5   . In this variant, adjustment of the distance between the rod  22  and the drive tie-rod  7  is done by adjusting the position along the slot  30  of the hinge pin  31  of the rod  22  on the lever  23  used to adjust the distance between the hinge pin  31  of the rod  22  and the fixed pivot pin  24  of the lever, and therefore also to adjust the distance between the pin  31  and the tie-rod  27 , the distance between the tie-rod  27  and the pin  24  being fixed in this variant, while in the method of implementation in  FIG.  5   , it is the distance between the pin  31  and the pin  24  that is fixed. 
       FIG.  5 B  shows a variant of the arrangement in  FIG.  5   . In this variant, the distance between the rod  22  and the drive tie-rod  27  is adjusted by adjusting the position along a slot  30 ′ formed in the lever  23  of the fixed pivot pin  24  of the lever. The pin  24  of the lever is rigidly connected to a slider  25 ′ that slides in the slot  30 ′. The rod  22  is hinged to the lever  23  at a hinge pin  31  which is fixed to the lever  23 . The hinge end of the tie-rod  27  to the lever  23  is in a fixed position (as in the method of implementation in  FIG.  5   ). Similarly, the pin  26  projecting from the adjustment tie-rod  28  is hinged to the lever  23  at a fixed position. By means of the tie-rod  28  the relative position of the pin  24  in relation to the lever  23  can thus be adjusted, thus adjusting the relative position of the tie-rod  27  to the pin  24  and the relative position of the rod  22  in relation to the pin  24 , and therefore adjusting the to and fro stroke of the tie-rod  27 , the distance between the tie-rod  27  and the rod  22  being fixed in this variant. 
       FIGS.  6 A and  6 B , show another method of implementation. The main difference between the method of implementation in  FIG.  5    and those in  FIGS.  6 A and  6 B  is the manner in which the position of the slider  25  is adjusted in relation to the slot  30 . 
     In this method of implementation, a spiral cam is used, consisting of a disk  40  containing a spiral slot along which the pin  26  can move. During rotation of the disk  40 , the pin  26  follows the profile of the spiral slot, which moves the pin  26  and therefore the slider  25  along the slot  30 . Depending on the position chosen for the pin  26  along the spiral, a given maximum to and fro stroke for the tie-rod  27  is obtained. 
       FIG.  7    shows yet another method of implementation in which a ram  41  is used instead of the crankshaft  29  in  FIG.  5   , the rest of the method of implementation being the same. 
     In the methods of implementation described in  FIGS.  6 A,  6 B and  7   , instead of the arrangement described here, in which it is the distance between the pin  24  and the tie-rod  27  that is adjusted (as in the variant in  FIG.  5   ), arrangements as in the variants in  FIGS.  5 A and  5 B  could be implemented. 
     The control or advance device or system according to the invention is shown here in combination with the needling machines in  FIGS.  1  to  4   . However it can also be used with other needling machines known from the prior art, for example, those known from EP-A1-1736586, EP-B1-3372716, FR2738846, U.S. Pat. No. 6,161,269 and the like. Thus, for example,  FIG.  8    shows yet another method of implementation of a needling machine comprising a control system according to the invention. 
     The housing here is shown in cross section, while the rest of the needling machine is shown in front view. 
     This needling machine comprises two needle plates  110  comprising needles  101  projecting from the lower face of their respective plate and arranged either in rows and columns, or randomly, or pseudo-randomly, as is well known in the field. Each needle plate  110  is carried by a beam  102 , called the moving beam. The respective beam  102  and plate  110  are connected rigidly together removably so that when the needles are worn and/or broken, a plate can easily be replaced with a new plate. The needles are designed to have a vertical to and fro motion from top to bottom and from bottom to top passing in one direction, then the other, over a fleece or web of fibres made to pass before them in the drive or MD direction, that is from left to right horizontally in the diagram. 
     Two longitudinal columns  103 , extending in the longitudinal, vertical axis  111  perpendicular to the plane of the plate, are each connected rigidly to a respective moving beam  102 . 
     Longitudinal drive systems are fitted to impart to each column  103  a straight, vertical to and fro motion parallel to the longitudinal axis  111 , which remains vertical throughout the motion. 
     A sealed housing  107  encloses the drive systems and part of each column  103 , the latter passing through the wall of the housing  107  through respective guide pots  104 . Each guide pot  104  is fixed in relation to the housing. During its vertical to and fro motion, each column  103  slides within the respective guide pot  104 . Guide bushes  118  are fitted inside the wall of each guide pot  104 , to ensure sliding and lubrication between the column  103  and the respective guide pot  104 . Oil-tightness between the column  103  and the guide pot  4 ″ is achieved by a seal (not shown) fixed to the base of the guide pot. 
     The longitudinal drive systems consist of two cam shaft systems  106  whose shafts drive the heads of two tie-rods rotating at the same speed in opposite directions. The feet of the two tie-rods are hinged to their respective column. 
     These longitudinal, vertical drive systems impart to each column  103  a solely to and fro motion in the longitudinal, vertical axis. 
     Control systems are also fitted, in particular to adjust the stroke of the needles. The control systems are fitted between the drive systems  106  and each column  103 . They comprise a lever  123  to which the rod  122  of the shaft  106  is hinged. The lever  123  pivots in relation to the offset pivot pin  124  in relation to the hinge pin of the rod  122  to the lever  123 . A tie-rod  127  is coupled to the lever  123 . The tie-rod  127  is rigidly connected to a slider  125  and one end of a pin  126  whose axis is parallel to pin  124 . 
     The lever comprises an opening in the form of a slot  130  in which the slider  125  slides linked rigidly in the translation of the pin  126  (pin  126  which can be seen better in  FIG.  7    which describes the same drive systems which comprise pin  26  corresponding to this pin  126 ). 
     The relative position of the pin  126  in relation to the pin  124  along the lever can be adjusted by means of an adjustment system consisting of a ram  141  and an adjustment tie-rod  128 , hinged at one end to the ram  141  and at its other end to the pin  126 . 
     Depending on the position of the tie-rod  128  which is determined by an appropriate movement of the ram  141 , the relative position of the slider  125  in the slot  130  can be chosen and adjusted to adjust the distance along the lever between the pin  124  and an axis of the pin  126 , this distance can thus be varied between a minimum (the slider  125  is at one end of the slot so that the axis of the pin  126  is as close as possible to the pin  124  and a maximum position, in which the slider  125  is at the other end of the slot, as far as possible from the pin  124 . 
     The amplitude of the to and fro motion of the tie-rod  127  can be varied either while running or at rest, the motion transmitted by movement of the ram  141  and the tie-rod  122  acting on the lever  123 . 
     In  FIG.  8   , it is the control system in  FIG.  7    which has been adapted to the needling machine, one of the control systems shown in  FIGS.  5  and  6 A and  6 B  could also have been adapted instead. 
     Furthermore, it would also be possible, while remaining within the scope of the invention, to fit an advance control system according to the invention in the methods of implementation in  FIGS.  1  to  4    to control the vertical motion of the columns of the elliptical needling machines described herein. In particular, it would also be possible in these methods of implementation to implement the advance control system of the invention either, as described in  FIGS.  1  to  4   , only for the MD component of the elliptical motion or, on the other hand, only for the vertical component of the elliptical motion, or for both the MD component and the vertical component, in particular by fitting two combined systems of the invention, one for the MD component and the other for the vertical component.