Patent Publication Number: US-11047079-B2

Title: Needle loom

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims priority based on European Patent Application No. EP 17 174 932.8, filed Jun. 8, 2017, the contents of which are incorporated by reference in its entirety. 
     FIELD OF THE INVENTION 
     The invention relates to a needle loom for needling a nonwoven web. 
     BACKGROUND OF THE INVENTION 
     Needle looms are generally known to the skilled person and are described in, for example, Lünenschloss and Albrecht: “Vliesstoffe” [Nonwovens], Georg-Thieme-Verlag, Stuttgart, 1982, pp. 122-129. 
     In needle looms, a nonwoven web is usually fed to the inlet side of the needle loom and conveyed in the web-conveying direction to a needling zone. In the area of the needling zone, at least one needle beam is arranged. A needle board, which is equipped with needles for consolidating the nonwoven, is attached to the beam. In this area, the nonwoven to be needled is usually guided between a stripper plate and a punching plate. To consolidate the nonwoven, the needles are pushed in a punching direction into the nonwoven and pulled back out again at high frequency. The needles pass through openings in the stripper plate and in the punching plate. The product thus being formed is a consolidated nonwoven. The person skilled in the art is familiar with a wide variety of forms of needle looms, including double needle looms, in which needling is performed from above and from below by two needle beams, and needle looms in which the needle beam is moved along with the nonwoven web in the conveying direction of the web during the consolidation process. 
     So that the needles arranged on the needle beam can be punched into the nonwoven web and pulled back out again, needle looms comprise a drive device, which causes the needle beam to execute a stroke in the punching direction. Such drive devices comprise, for example, two main shafts, on each of which a main conrod is eccentrically supported, so that a rotational movement of the main shafts is converted by the main conrods into a stroking movement of the needle beam in the punching direction. The main shafts can be coupled to each other by a gear stage and preferably turn in opposite rotational directions. This makes it possible to neutralize the forces acting transversely to the punching direction which can be caused by the eccentric movement of the main conrod. Because the two main shafts are coupled by a gear stage, it is sufficient for only one of the main shafts to be driven in rotation by a drive. 
     Needle looms in which the needle beam is to be moved along in the conveying direction of the nonwoven web during the consolidation process usually also comprise a secondary drive or at least a horizontal guide. As a result of the superimposition of the stroking movement of the needle beam in the punching direction on the stroking movement of the needle beam in the conveying direction of the nonwoven web, the needle beam is moved around a substantially elliptical path. Needle looms of this type are known from, for example, U.S. Pat. No. 6,161,269. 
     It is desirable to have the ability to adapt the stroke of the needle beam in the conveying direction of the nonwoven web to the requirements in the individual case. 
     One possibility of making such an adjustment consists in shifting the phasing of the two main shafts. Depending on the phasing of the main shafts with respect to each other, a form of movement similar to an ellipse is obtained, which the oscillating movement of the needle beam executes. Examples of needle looms which make it possible to adjust the phasing of the main shafts with respect to each other can be found in U.S. Pat. No. 7,107,658 B2 and in U.S. Pat. No. 8,793,848 B2. The adjusting of the phasing, however, must be accomplished manually and off-line. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a needle loom for needling a nonwoven web in which the phasing of the main shafts can be adjusted in a mechanically simple manner even during the operation of the needle loom. 
     According to an aspect of the invention, a needle loom for needling a nonwoven web comprises a needle beam arrangement with least one needle beam and further comprises a drive device for moving the needle beam arrangement back and forth in a punching direction. The drive device comprises a drive and a first main shaft and a second main shaft, wherein a first main conrod is eccentrically supported on the first main shaft and connects the first main shaft to the needle beam arrangement in articulated fashion, and wherein a second main conrod is eccentrically supported on the second main shaft and connects the second shaft to the needle beam arrangement in articulated fashion. The first and second main shafts are driven so that they rotate in opposite directions. The drive devices comprises an endless transmission element, which couples the first and second main shafts together. The transmission element also passes over a first and a second adjusting roller. An adjusting device is provided for the translational adjustment of the position of the first and second adjusting rollers. The translational adjustment of the position of the first and second adjusting rollers by the adjusting device brings about a rotational adjustment of the phasing of the first and second main shafts with respect to each other. 
     With this configuration, a needle loom for needling a nonwoven web is created by the phasing of the main shafts which can be adjusted in a mechanically simple manner. 
     A first disk-shaped engagement element with a substantially circular cross section is preferably connected nonrotatably to the first main shaft, and a second disk-shaped engagement element with a substantially circular cross section is connected nonrotatably to the second main shaft. These engagement elements cooperate with the transmission element. The first and second engagement elements are preferably configured as toothed-belt pulleys. In this way, force can be reliably transmitted between the transmission element and the engagement elements, and thus the two main shafts can be reliably coupled to each other. A double-sided toothed belt is especially well-adapted for use as the transmission element. 
     In a preferred embodiment, the circumference of the first and second engagement elements is larger than the circumference of the first and second adjusting rollers. Thus the phase angle of the two main shafts to each other can be adjusted with an especially high degree of accuracy. 
     A reliable coupling of the two main shafts, which are to be driven in opposite directions, is guaranteed when a first side of the transmission element engages with a circumferential region of the first engagement element, and the second side of the transmission element engages with a circumferential region of the second engagement element. 
     It is especially preferred that the transmission element be arranged substantially in the form of a sideways-oriented U-shape. 
     In this case, it is preferable for the first and second engagement elements to be arranged next to each other in the area of a base section of the U-shape of the transmission element in such a way that an outer loop of the transmission element wraps around the circumferential region of the first engagement element in the area of the base section of the U-shape, and an inner loop of the transmission element wraps around the circumferential region of the second engagement element in the area of base section of the U-shape. 
     It is also preferable for the first adjusting roller to be arranged on an end section of a first leg of the U-shape of the transmission element in such a way that a loop of the transmission element wraps around a circumferential region of the first adjusting roller, and for the second adjusting roller to be arranged on an end section of a second leg of the U-shape of the transmission element in such a way that a loop of the transmission element wraps around a circumferential region of the second adjusting roller. 
     As the transmission element travels around the first adjusting roller and around the second adjusting roller, the transmission element preferably undergoes a substantially 180° turn in each case. 
     The adjusting device preferably comprises a pivotable arm, on the opposite ends of which the first and second adjusting rollers are supported. Because of the symmetric structure, therefore, a length compensation of the transmission element upon the pivoting of the pivotable arm can be easily achieved. 
     In a preferred embodiment, the adjusting device comprises a spindle stroking device for the translational adjustment of the first adjusting roller. In this way, the translational adjustment of the first adjusting roller can be achieved with especially good accuracy. 
     In this case it is possible for the adjusting device to comprise a tensioning device for applying a pretension to the second adjusting roller. In this way, a length compensation of the transmission element upon the translational adjustment of the first adjusting roller can be easily achieved. Alternatively, the adjusting device can comprise an additional spindle stroking device for the translational adjustment of the second adjusting roller. 
     It is especially preferable for the adjusting device to be actuated by a motor. In this way, the control of the phase adjustment of the main shafts can be achieved automatically in a closed-loop manner. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic perspective view of an embodiment of a needle loom according to the invention; 
         FIG. 2  is a schematic side view of essential components of an embodiment of a needle loom according to the invention; 
         FIG. 3  is a schematic side view of essential components of another embodiment of a needle loom according to the invention; 
         FIG. 4  is a schematic side view of essential components of another embodiment of a needle loom according to the invention; 
         FIG. 5  is a schematic side view of essential components of another embodiment of a needle loom according to the invention; and 
         FIG. 6  is a schematic side view of essential components of another embodiment of a needle loom according to the invention. 
     
    
    
     DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS 
     The drawings show only the components of a needle loom which are essential to the description of the invention. For example, the machine housing, the stripper plate, and the punching plate, the arrangement of which is familiar to the skilled person, are not shown for the sake of clarity. The nonwoven web to be needled is not shown either. 
       FIG. 1  shows a schematic diagram, in perspective, of part of an embodiment of a needle loom  1  according to the invention. The needle loom  1  comprises a needle beam arrangement  10  and a drive device  20 . The needle beam arrangement  10  comprises at least one needle beam  12 . In the embodiment shown here, two needle beams  12  are provided, which are attached to a needle beam carrier  11  and are supported by it. It is obvious that, depending on the existing requirements, it is also possible to use only one needle beam  12  or as many additional ones as desired. By way of example, a needle board with only single needles at the edges is shown here, these needles projecting from the surface of each of the needle beams  12  facing away from the drive device  20 . It is obvious that, in an actual realization of a needle loom  1  according to the invention, multiple rows of needles will be arranged on the bottom surface of each needle board. 
     In the exemplary embodiment described here, the punching direction of the needles into the nonwoven web, indicated in  FIG. 1  by the arrow E, is oriented vertically. It is obvious that a deviation from a precisely vertical orientation is possible under certain conditions. A needle beam guide  46  is provided to guide the needle beam arrangement  10  in the punching direction E and possibly also to guide the needle beam arrangement  10  in the conveying direction F of the nonwoven web. Such guides are generally known and will not be described in greater detail here. 
     The drive device  20  moves the needle beam arrangement  10  back and forth in the punching direction E. This normally corresponds to a vertical stroking movement of the needle beam  12 . The drive device  20  comprises a drive  22 , a first main shaft  24 , a first main conrod  26 , a second main shaft  30 , and a second main conrod  32 . The first main conrod  26  and the second main conrod  32  are each connected to the needle beam arrangement  10  in articulated fashion and are preferably fastened to the needle beam carrier  11 . The first main conrod  26 , at the end facing away from the needle beam arrangement  10 , is connected in articulated fashion to the first main shaft  24 , whereas the second main conrod  32 , at the end facing away from the needle beam arrangement  10 , is connected to the second main shaft  30  in articulated fashion. The first and second main conrods  26 ,  32  are connected to the first and second main shafts  24 ,  30  in such a way that a rotational movement of the main shafts  24 ,  30  is converted into a substantially linear movement of the needle beam arrangement  10 . Especially well adapted to use for this purpose is an eccentric connection of the main conrods  26 ,  32  to the main shafts  24 ,  30 , wherein in each case a conrod eye is rotatably supported on an eccentric section of the shaft in question. 
     The main shafts  24 ,  30  are driven by the drive  22  so that they rotate in opposite directions, as indicated by the arrows. The required gear arrangement  34  for coupling the two main shafts  24 ,  30  is described in greater detail on the basis of the following drawings and is indicated only schematically in  FIG. 1  for the sake of clarity. An electric motor, for example, is suitable as the drive  22 . In addition to the direct connection shown between the drive  22  and the second main shaft  30 , it is also possible to connect the drive  22  indirectly, i.e., by a belt transmission with a toothed belt, to the main shaft  30 . Similarly, the first main shaft  24  can be the main shaft which is driven directly. This is the preferred situation, as shown in the exemplary embodiments according to  FIGS. 2-6 . 
       FIGS. 2-6  show only the components of the needle loom  1  which are relevant to the phase adjustment of the main shafts  24 ,  30 . 
     As shown in  FIG. 2 , the drive device comprises an endless transmission element  14 , which couples the first and second main shafts  24 ,  30  to each other. The transmission element  14  is preferably configured as a double-sided toothed belt. The width of the transmission element  14  is usually in the range of 80-120 mm. So that force can be transmitted between the transmission element  14  and the two main shafts  24 ,  30 , engagement elements  38 ,  40  must be provided on the main shafts  24 ,  30 , with which the transmission element  14  can engage. In the embodiment shown here, these engagement elements  38 ,  40  are configured as toothed-belt pulleys, which are connected nonrotatably to the associated main shafts  24 ,  30 . Many other configurations could be considered, however, such as a chain as the transmission element  14  and sprockets as the engagement elements  38 ,  40 . 
     The transmission element  14  is arranged substantially as a sideways-oriented U-shape. More concretely expressed, the first and second engagement elements  38 ,  40  are arranged next to each other in the area of a base section  42  of the U-shape of the transmission element  14  in such a way that an outer loop of the transmission element  14  wraps around a circumferential region of the first engagement element  38  in the area of the base section  42  of the U-shape, and an inner loop of the transmission element  14  wraps around a circumferential region of the second engagement element  40  in the area of the base section  42  of the U-shape. 
     The transmission element  14  also passes over two adjusting rollers  16 ,  18 . The first of these adjusting rollers  16  is arranged at an end section of a first leg  48  of the U-shape of the transmission element, and the second adjusting roller  18  is arranged at an end section of a second leg  50  of the U-shape of the transmission element  14 . One loop of the transmission element  14  thus wraps around a circumferential region of the first adjusting roller  16 , and another loop of the transmission element  14  wraps around a circumferential region of the second adjusting roller  18 . As transmission element  14  passes around the first adjusting roller  16  and around the second adjusting roller  18 , it undergoes a 180° turn in each case. 
     In the present case, the two adjusting rollers  16 ,  18  are oriented vertically with respect to each other. The adjusting rollers  16 ,  18  in the embodiment shown here are, with respect to their horizontal orientation, located laterally next to the two engagement elements  38 ,  40 , wherein the first adjusting roller  16  is also, with respect to its vertical orientation, above the engagement elements  38 ,  40 , and the second adjusting roller  18  below the engagement elements  38 ,  40 . It is preferable for the circumference of the engagement elements  38 ,  40  to be larger than the circumference of the first and second adjusting rollers  16 ,  18 . 
     As a result of this arrangement, a first side of the transmission element  14  engages with a circumferential region of the first engagement element  38 , and a second side engages with a circumferential region of the second engagement element  40 . Because of this coupling of the two main shafts  24 ,  30  by way of the transmission element  14 , only one of the two main shafts  24 ,  30  must be actively driven by the drive  22  during the operation of the needle loom  1 , whereas the other one of the two main shafts  23 ,  40  is driven indirectly by way of the transmission element  14  in the opposite rotational direction. 
     An adjusting device  36  for the translational adjustment of the position of the first and second adjusting rollers  16 ,  18  is also provided. In the exemplary embodiment of  FIG. 2 , the adjusting device  36  comprises a pivotable arm  52 , at the opposing end areas of which the first and second adjusting rollers  16 ,  18  are rotatably supported. The pivot axis  53  of the pivotable arm  52  is arranged at substantially the center of the pivotable arm  52 . To achieve the desired pivoting of the pivotable arm  52 , a spindle stroking device  54 , which acts on an outer end section of the arm  52 , is provided. By pivoting the arm  52 , the spindle stroking device  54  leads to a translational adjustment of the first and second adjusting rollers  16 ,  18  in opposite directions. 
     As a result of the U-shaped arrangement of the transmission element  14 , a translational adjustment of the adjusting rollers  16 ,  18  in opposite directions brings about, while the engagement element  38  is stationary (i.e., while the main shaft  24  is kept stationary), a rotation of the second engagement element  40  around a certain angle α. This angle α is correlated with the pivot angle β of the pivotable arm  52 . When, in the example of  FIG. 2 , the spindle stroking device  54  travels toward the left, the second adjusting roller  18  therefore also shifts toward the left, whereas the first adjusting roller  16  shifts toward the right. Because of the engagement of the teeth of the transmission element  14  with the adjusting rollers  16 ,  18 , the transmission element  14  moves in a clockwise direction in the area of the second engagement element  40  and thus turns the second engagement element  40  and the second main shaft  30  connected to it around the angle α onward in the clockwise direction. As a result, a phase difference between the two main shafts  24 ,  30  is produced. If there was already a phase shift between the main shafts  24 ,  30 , this can be adapted in the manner just described. 
     It would also be possible to keep the second engagement element  40  stationary instead of the first engagement element. Then the translational adjustment of the adjusting rollers  16 ,  18  brings about a rotation of the first engagement element  38  around the angle in the counterclockwise direction. Finally, it is also conceivable that an adjustment of the relative phase angle α of the two main shafts  24 ,  30  to each other could be produced by allowing the two main shafts  24 ,  30  to rotate in opposite directions upon the adjustment of the adjusting rollers  16 ,  18 . 
     By the arrangement described above, it is possible to adjust the phase angle even during ongoing operations. The angle α typically has a value in the range of 1-20°. In this way, a horizontal stroke of the needle beam arrangement  10  can be easily set to a value in the range of 1-15 mm by changing the phasing of the two main shafts  24 ,  30  to modify the tipping movement of the needle beam and the elliptical curve of its movement. 
     The embodiment according to  FIG. 3  corresponds to the embodiment of  FIG. 2  with the difference that the translational adjustment of the first adjusting roller  16  and of the second roller  18  is achieved in a different manner. The adjusting device  36  comprises now a spindle stroking device  54 , which can move the first adjusting roller  16  actively back and forth. The spindle stroking device  54  is driven by a motor  60 , which can be a servo motor, for example. This is preferably done by element of a toothed belt  62  and belt pulleys  64 , but obviously there are also other ways in which the force could be transmitted from the motor  60  to the spindle stroking device  54  such as by a chain and sprockets. 
     To ensure the length compensation function for the loops of the transmission element  14  without any change in the tension of the transmission element  14 , the second adjusting roller  18  is supported on a tensioning device  56 . The tensioning device  56  can contain, for example, a compression spring, which pushes the second adjusting roller  18  in a direction toward the second leg  50  of the U-shape of the transmission element  14 . It would also be possible for the tensioning device  56  to contain a tension spring or some other type of tensioning element. 
     In the embodiment according to  FIG. 4 , a similar configuration of the adjusting device  36  is shown, in which the position of the first adjusting roller  16  is shifted in a manner nearly identical to that used in the exemplary embodiment according to  FIG. 3 . Here, however, a second spindle stroking device  58  is provided to shift the position of the second adjusting roller  18 . The two spindle stroking devices  54 ,  58  can be actuated by separate drives, but it is a logical option to use the same motor  60  to drive both spindle stroking devices  54 ,  58  to ensure in a simple manner that both adjusting rollers  16 ,  18  experience a translation distance of the same absolute value but in opposite directions. Again, a toothed belt  62  and belt pulleys  64  can be used to transfer force between the motor  60  and the spindle stroking devices  54 ,  58 . It would also be possible to use chains and sprockets or similar, known force-transmitting mechanisms. 
     A simultaneous clockwise movement of the two belt pulleys  64 , which are connected to the first and second spindle stroking devices  54 ,  58 , brings about, for example, a retraction of the first spindle stroking device  54  and thus a movement of the first adjusting roller  16  toward the right. Simultaneously, the spindle stroking device  58  is extended, and the second adjusting roller  18  is moved to the left by the same amount. 
     The embodiment shown in  FIG. 5  corresponds substantially to the embodiment according to  FIG. 2 , wherein two passive deflecting pulleys  66  instead of the two adjusting rollers  16 ,  18  are arranged in the area of the end sections of the two legs  48 ,  50  of the U-shape of the transmission element  14 . The adjusting rollers  16 ,  18 , in contrast, are, with respect to their horizontal orientation, arranged in the area between the two engagement elements  38 ,  40  and are oriented vertically with respect to each other. One of the adjusting rollers  16  is arranged above the engagement elements  38 ,  40 , the other one below. 
     The two adjusting rollers  16 ,  18  are preferably supported on a carrier  68 , which can be moved back and forth in the up and down directions by a spindle stroking device  54 . As a result of this vertical displacement, a phase adjustment of the two main shafts  24 ,  30  with respect to each other by the angle α is again achieved. 
     It would also be conceivable that the two adjusting rollers  16 ,  18  could be arranged in the position shown in  FIG. 5 , but on a pivotable arm like the arm of  FIG. 2 . A pivoting movement of this arm would then achieve a similar effect. 
     The embodiment of  FIG. 6  corresponds to the embodiment of  FIG. 2 , the only difference being that the needle beam guide  46  is configured here as a cam lever guide. A cam lever guide could also be used as the needle beam guide  46  in the embodiments shown in  FIGS. 3-5 . 
     In addition to the relative geometric arrangements of the engagement elements  38 ,  40  and of the adjusting rollers  16 ,  18  shown here, the skilled person will perceive that there are also many other arrangements which are possible within the scope of the invention. The important point in each case is that, because of the geometric arrangement of the elements with respect to each other, a translational adjustment of the position of the two adjusting rollers  16 ,  18  will automatically result in a rotational adjustment of one of the two engagement elements  38 ,  40  and thus of one of the two main shafts  24 ,  30  with respect to the other. 
     Each of the spindle stroking devices  54 ,  58  can be actuated by a motor. Each of the spindle stroking devices  54 ,  58  can also be monitored by sensors. 
     A display unit, which shows the extent of the horizontal stroke in millimeters, is preferably available at the control panel of the needle loom. The operator can preferably set the horizontal stroke by way of an input device, and a controller will control the motor  60  of the adjusting device  36  on the basis of the input value. For this purpose, the controller can make use of data stored in a library, for example. 
     It is especially preferable for the adjusting process to be conducted under closed-loop control. The actual values which are required for this closed-loop control and which are compared with stored nominal values can be acquired by the sensor technology of the adjusting device itself, or preferably by a sensor which detects the extent of the horizontal stroke. 
     Overall, the present invention makes it possible to achieve a relatively simple electromechanical adjustment of the phase angle of the two main shafts of a needle loom with respect to each other. 
     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.