Abstract:
The invention relates to a device for needling a web of fiber, said device comprising at least one driven needle beam. A vertical reciprocal movement of the needle beam is carried out by a vertical drive unit and a superposed horizontal reciprocal movement is carried out by a horizontal drive unit or due to a phase adjustment by the vertical drive unit. A weight balancing device is provided for balancing the inertia forces of the crank mechanisms. In order to be able to balance both vertical and horizontal inertia forces in a simple manner, the weight balancing device is formed by at least one balance weight which is associated with the crank mechanism of the vertical drive unit and which is set-off by an angle in the range of &lt;180° from an eccentric element of the crank mechanism.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention concerns a device for needling of a fiber web. 
     2. Description of Related Art 
     In devices for needling of a fiber web, a needle beam, on whose bottom a number of needles are held, is driven in an oscillating up-and-down movement, so that the needles repeatedly perforate the fiber web guided on a substrate. Crank mechanisms are ordinarily used to drive such needle beams, in which an eccentrically rotating eccentric weight for weight balancing is ordinarily compensated by corresponding balancing weights on the crankshaft. The inertial effects, because of the rotating and oscillating weight within the device, can be kept low, so that no inadmissible vibrations in the machine frame occur. In order to achieve higher production speeds during needling of a fiber web, drive concepts of the needle beam are now known, in which a superimposed back-and-forth movement of the needle beam aligned in the horizontal direction is generated relative to the up-and-down movement. Such a device is known, for example, from DE 196 15 697 A1. 
     In the known device, the needle beam is driven by a vertical drive mechanism in an up-and-down movement and by a horizontal drive mechanism in a superimposed back-and-forth movement. The inertial forces in the device occur both in the vertical direction and in the horizontal direction. To balance the weight and inertia, several balancing shafts are arranged in the known device in the machine frame, which counteract the weight and inertia of the crank mechanisms by oppositely rotating eccentric masses. This form of balancing is technically very demanding and requires significant space requirements within the device. The free weight forces and inertial forces occurring with variable stroke adjustment of the horizontal drive mechanism are particularly problematical, since they increase quadratically with stroke frequency and linearly with stroke height. Higher stroke frequencies and therefore higher production speeds, as well as greater horizontal strokes of the needle beam in the known device, therefore necessarily lead to increased vibrations in the machine frame. Such vibrations, however, are very negative with respect to noise, and especially with respect to product quality. 
     The task of the invention is therefore to design a device for needling of a fiber web of the generic type, so that balancing of the inertial forces occurring in the vertical and horizontal direction is possible by simple means. 
     Another objective of the invention is to provide a device of the generic type that permits variable stroke adjustments of the needle beam with relatively large horizontal strokes and high stroke frequencies. 
     SUMMARY OF VARIOUS EMBODIMENTS 
     This task is solved according to the invention by a device with the features described herein. 
     Advantageous modifications of the invention are also defined by the features and feature combinations described herein. 
     The invention is separated from the principle of compensating for inertial forces acting on a crank mechanism by a counterweight, which is arranged in an eccentric plane opposite the eccentric weight. The invention is based on the finding that the crank mechanism of the vertical drive mechanism can be used to counteract the horizontally directed inertial forces, in addition to the vertically directed inertial forces. For this purpose, a balancing weight of the weight balancing device is assigned to the crank mechanism of the vertical drive mechanism and offset by an angle in the range &lt;180° relative to an eccentric of the crank mechanism. The size of the balancing weight and the angular position of the balancing weight on the crank mechanism can be chosen as a function of the weight forces and the inertial forces acting in the vertical and horizontal directions. Balancing functions can therefore be implemented on the existing crank mechanisms, which would otherwise be achieved only by additional balancing shafts or other demanding measures. The balancing weight for this purpose is arranged directly on a crankshaft or an eccentric shaft of the crank mechanism. In this case, it is unessential whether the superimposed horizontal movement of the needle beam is produced by a horizontal drive mechanism or during phase adjustment directly by the vertical drive mechanism. In each case, the occurring horizontal inertial forces can be balanced by the balancing weight on the crank mechanism of the vertical drive mechanism. 
     In a particularly preferred modification of the invention, the balancing weight is offset by an angle of 90° to the eccentric of the crank mechanism and a second balancing weight is offset by an angle of 180° to the eccentric of the crank mechanism. The vertical inertial forces of the needle beam on the crank mechanism can therefore be fully compensated. The balancing weight, arranged offset by 90° to the eccentric weight of the crank mechanism, is then opposite the horizontal inertial forces. At constant horizontal stroke of the needle beam, complete weight balancing can be implemented. The needle beam can be operated with correspondingly high stroke frequencies, without inadmissible vibrations becoming active on the machine frame. 
     The balancing weights assigned to a crank mechanism can be the same or different in size. The choice of size of the balancing weight is essentially dependent on the inertial forces occurring during operation. 
     In order to achieve parallel guiding of the needle beam within a machine frame, the vertical drive mechanism is preferably formed by two synchronously running drive mechanisms. In this case, according to an advantageous modification of the invention, one or more balancing weights is assigned to each crank mechanism. Each crank mechanism can therefore be used for weight balancing of the vertical and horizontal inertial forces. The balancing weights on the crank mechanisms of the vertical drive mechanism can be designed identical or different on each of the crank mechanisms. For example, one of the crank mechanisms can be equipped with two balancing weights, whereas the second crank mechanism receives only one balancing weight. 
     In particularly complex drive concepts of the needle beam, the balancing device can also be expanded, in that an additional balancing shaft is arranged within the machine frame with a rotating eccentric weight. The inertia within the machine frame, in particular, can be fully compensated by this. Depending on the drive concept, the balancing shaft can be equipped with a rotating eccentric weight or with two rotating eccentric weights offset by 90°. 
     For a case, in which the horizontal movement is produced by phase adjustment of the vertical drive mechanism, the phase adjustment device preferably has two separately controllable servo motors assigned to the crankshafts of the crank mechanisms of the vertical drive mechanism. Depending on the phase difference between the crankshafts, strokes of different height can then be implemented in the horizontal movement. For weight and inertial balancing, the balancing shaft is preferably arranged symmetric to the two crankshafts of the crank mechanisms. 
     In order to be able to directly compensate the inertial forces acting in the horizontal drive mechanism with a separate drive mechanism of the horizontal drive mechanism, according to an advantageous modification of the invention, at least one additional balancing weight is assigned to the crank mechanism of the horizontal drive mechanism and arranged offset by an angle in the range &lt;180° to the eccentric of the crank mechanism. 
     However, as an alternative, there is also the possibility to choose the arrangement of balancing weights on the crank mechanism of the horizontal drive mechanism, so that the balancing weight is offset by 90° relative to the eccentric and a second balancing weight is arranged opposite the eccentric weight. 
     In order to achieve the most flexible possible horizontal drive of the needle beam, the horizontal drive mechanism is preferably formed by two synchronously running crank mechanisms. In this case, at least one of the balancing weights is advantageously assigned to each of the crank mechanisms. 
     In order to permit variable stroke adjustment, the crank mechanisms of the horizontal drive mechanism can be driven oppositely and their phase positions designed adjustable. Through the balancing weights assigned to the crank mechanisms, variable inertial forces can be compensated, in addition to the constant inertial forces. With appropriate choice of balancing weights, the resulting inertial force therefore disappears approximately for each horizontal stroke adjustment between zero and a maximum stroke. 
     In order to obtain the most stable possible guiding of the drive movement of the needle beam, the crank mechanisms and horizontal drive mechanism are preferably connected to the needle beam by a coupling mechanism. The drive movement of the crank mechanisms can thus be converted by the coupling mechanisms into an almost exclusive grade movement on the needle beam. 
     The crank mechanisms of the vertical drive mechanism and the horizontal drive mechanism are ordinarily designed by means of a driven crankshaft or driven eccentric shaft, which are connected to a connecting rod via a connecting rod small end. 
     To balance the inertial forces, the balancing weights are mounted directly on the crankshaft or on the eccentric shaft. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       The device according to the invention is further explained below by means of the practical example with reference to the accompanying figures. 
       In the figures: 
         FIGS. 1.1  and  1 . 2  schematically depict a side view of a first practical example of the device according to the invention 
         FIG. 2  schematically depicts a side view of a practical example of a crank mechanism with weight balancing 
         FIGS. 3.1  and  3 . 2  schematically depict a side view of another practical example of the device according to the invention 
         FIG. 4  schematically depicts a side view of another practical example of the device according to the invention 
         FIG. 5  schematically depicts a side view of another practical example of the device according to the invention 
     
    
    
     DETAILED DESCRIPTION 
     In  FIGS. 1.1  and  1 . 2 , a first practical example of the device according to the invention for needling of a fiber web is shown. The practical example is shown in different operating situations in  FIGS. 1.1  and  1 . 2 . The description therefore applies to both figures. The practical example of the device according to the invention has a beam support  2 , which holds a needle beam  1  on the bottom. The needle beam  1  holds a needle board  24  on its bottom with a number of needles  25 . 
     A vertical drive mechanism  3  and a horizontal drive mechanism  10  engage on the beam support  2 . The beam support  2  is moved oscillating in the vertical direction via the vertical drive mechanism  3 , so that the needle beam  1 , with needle board  24 , executes an up-and-down movement. The vertical drive mechanism  3  is formed by two parallel crank mechanisms  4 . 1  and  4 . 2 . The crank mechanisms  4 . 1  and  4 . 2  have two parallel crankshafts  5 . 1  and  5 . 2  arranged above the beam support  2 . The crankshafts  5 . 1  and  5 . 2  each have at least one eccentric  6 . 1  and  6 . 2  to accommodate a connecting rod  7 . 1  and  7 . 2 . 
     The connecting rods  7 . 1  and  7 . 2  arranged on the beam support  2  are shown in  FIG. 1 , which are held with their connecting rod small ends on the eccentrics  6 . 1  and  6 . 2  of the crankshafts  5 . 1  and  5 . 2 . Additional (not shown here) connecting rods can be arranged on crankshafts  5 . 1  and  5 . 2 . 
     The connecting rods  7 . 1  and  7 . 2  are connected with their free ends to the beam support  2  via pivot joints  8 . 1  and  8 . 2 . The crankshafts  5 . 1  and  5 . 2  are driven synchronously in the same or opposite direction, so that the beam support  2  is guided at least roughly parallel. 
     For superimposed horizontal movement of needle beam  1 , the horizontal drive mechanism  10  engages via a crank mechanism  11 . 1  directly on the beam support  2 . The crank mechanism  11 . 1  of the horizontal drive mechanism  10  has a crankshaft  12 . 1  and a connecting rod  14 . 1  for this purpose. The connecting rod  14 . 1  is connected via an eccentric  13 . 1  to crankshaft  12 . 1 . On the free end, the connecting rod  14 . 1  is coupled to the beam support  2  via a pivot joint  15 . The crankshaft  12 . 1  is driven synchronously to the crankshafts  5 . 1  and  5 . 2  of the vertical drive mechanism, so that the needle beam  1  executes a lifting movement with a constant horizontal stroke. 
     A weight balancing device to balance the inertial forces of the crank mechanisms is assigned to the vertical drive mechanism  3  in the horizontal drive mechanism  10 . The weight balancing device here is formed by several balancing weights assigned to the crank mechanisms  4 . 1 ,  4 . 2  and  5 . 1 . The crank mechanism  4 . 1  has balancing weights  9 . 1  and  9 . 2 . The balancing weight  9 . 1  is arranged offset by an angle of 180° to the eccentric  6 . 1  on crankshaft  5 . 1 . The balancing weight  9 . 2  is offset by an angle of 90° to the eccentric  6 . 1  on crankshaft  5 . 1 . 
     A third balancing weight  9 . 3  is arranged as counterweight on crankshaft  4 . 2 . For this purpose, the balancing weight  9 . 3  is offset by an angle of 180° to the eccentric  6 . 2  on crankshaft  5 . 2 . 
     The balancing weights  16 . 1  and  16 . 2  are assigned to the crankshaft  11 . 1  of the horizontal drive mechanism  10 . The balancing weight  16 . 1  is offset by an angle of 180° to the eccentric  13 . 1  on crankshaft  12 . 1 . The other balancing weight  16 . 2  is offset by an angle of 90° to the eccentric  13 . 1  on the crankshaft  12 . 1 . 
     To further explain the weight balancing device, the practical example in  FIG. 1.1  is shown in an operating situation, in which the needle beam is shown in its upper position with vertically directed inertial forces. The practical example in  FIG. 1.2 , on the other hand, is shown in a middle beam position, in which horizontal inertial forces are active. 
     In the situations depicted in  FIG. 1.1 , the inertial forces generated by the balancing weights  9 . 1 ,  9 . 2 ,  9 . 3 ,  16 . 1  and  16 . 2  are shown as vectors. The force vector of the balancing weight  9 . 1  is marked with the code letters F E1 . The inertial force of the balancing weight  9 . 2  on crank mechanism  4 . 1  is accordingly marked by the letters F N1 . Similarly, the force vector of the balancing weight  9 . 3  assigned to crank mechanism  4 . 2  is marked with the letters F E2 . The balancing weights  16 . 1  and  16 . 2  assigned to the crank mechanism  11 . 1  of the horizontal drive mechanism  10  are marked by the letters F N3  and F E3  and as force vectors. 
     In the operating positions depicted in  FIGS. 1.1  and  1 . 2 , the inertial force F B  engaging on the needle beam is compensated by the forces F E1 +F E2 +F E3  of the balancing weights  9 . 1 ,  9 . 2  and  9 . 3  of the crank mechanisms  4 . 1  and  4 . 2 . In the depicted operating positions, the inertial forces F N1  and F N3  of the balancing weights  9 . 2  and  16 . 2  are opposite. It is therefore possible to balance the horizontal and vertical inertial force with the balancing weights  9 . 1 ,  9 . 2  and  9 . 3 . The balancing weights  9 . 2  and  16 . 2 , which produce the inertial forces F N1  and F N3 , are now chosen, so that they mutually cancel out in each position of the needle beam and produce an inertia to compensate for the inertia caused by the action line distance between the beam forces and balancing forces. 
     In the practical examples depicted in  FIGS. 1.1  and  1 . 2 , there are essentially two possibilities for mounting the balancing weights on the corresponding crank mechanisms. Another possible arrangement of a balancing weight is shown in  FIG. 2 , as can be performed as an alternative on the crank mechanism  4 . 1  of the vertical drive mechanism  3  of the crank mechanism  11 . 1  of the horizontal drive mechanism  10 . For this purpose, a balancing weight  9 . 2  is assigned to the crank mechanism  4 . 1 . The balancing weight  9 . 2  is offset by an angle a to the eccentric  6 . 1  of the crankshaft  5 . 1 . The angle a is &lt;180° and is preferably chosen so that both horizontally acting and vertically acting forces can be compensated by the balancing weight  9 . 2 . The number of balancing weights can therefore be reduced with an equivalent effect. 
     Another practical example of the device according to the invention is schematically depicted in  FIGS. 3.1  and  3 . 2  in a side view in several operating positions. The practical example according to  FIGS. 3.1  and  3 . 2  is essentially identical to the practical example according to  FIGS. 1.1  and  1 . 2 , so that only the differences are explained here and otherwise reference is made to the aforementioned description. The practical example in  FIG. 3.1  is shown in an upper position of the needle beam and  FIG. 3.2  in a middle position of the needle beam. 
     In the practical example depicted in  FIGS. 3.1  and  3 . 2 , two needle beams  1 . 1  and  1 . 2  are held on the beam supports  2 , each of which carries a needle board  24  and a number of needles  25  on their bottoms. The beam support  2  is connected to a vertical drive mechanism  3 , designed identical to the aforementioned practical example. For horizontal movement of the beam support  2 , the beam support  2  is connected to a linkage  19  via a pivot joint  15 . In this practical example, the pivot joint  15  is arranged essentially with the pivot joints  8 . 1  and  8 . 2  to connect the vertical drive mechanism  3  at a common height on beam support  2 , so that the linkages  19  arranged relative to the transverse sides of the beam support  2  permit force introduction and guiding of the beam support  2 . 
     For deflection of linkage  19 , a horizontal drive mechanism  10  is provided, which is formed by two crank mechanisms  11 . 1  and  11 . 2 . The crank mechanisms  11 . 1  and  11 . 2  each have a crankshaft  12 . 1  and  12 . 2  arranged parallel to each other and, together with crankshafts  5 . 1  and  5 . 2  of vertical drive mechanism  3 , form a common drive plane. The crankshafts  12 . 1  and  12 . 2  are each connected to a connecting rod  14 . 1  and  14 . 2  via their eccentrics  13 . 1  and  13 . 2 . The connecting rods  14 . 1  and  14 . 2  are directed toward each other with an oblique position, so that the free ends of the connecting rods  14 . 1  and  14 . 2  are connected together to a coupling mechanism  17  via a double pivot joint  21 . 
     The coupling mechanism  17  in this practical example consists of a toggle lever  18 , which is mounted to pivot on a pivot bearing  26 . The toggle lever  18  has a pivot joint on the free end beneath pivot bearing  26 , with which the linkage  19  is connected to toggle lever  18 . Another pivot joint is provided on the opposite free end of toggle lever  18 , on which a push rod  20  engages. The push rod  20  is connected to connecting rods  14 . 1  and  14 . 2  with an opposite end through double pivot joint  21 . 
     The crankshafts  12 . 1  and  12 . 2  of the crank mechanisms  11 . 1  and  11 . 2  are driven oppositely with the same speed, in which the phase positions of the crankshafts  12 . 1  and  12 . 2  are adjustable relative to each other as a function of a desired horizontal stroke. The phase positions and therefore the desired horizontal stroke of crankshafts  12 . 1  and  12 . 2  can be accomplished, for example, by two separate servo motors that produce a rotation of crankshafts  12 . 1  and  12 . 2  relative to each other. Drive of crankshafts  14 . 1  and  14 . 2  can be accomplished by a common drive or separately by separate drives. 
     To compensate for inertial forces on the crank mechanisms  4 . 1 ,  4 . 2 ,  11 . 1  and  11 . 2 , a balancing device is provided, which is formed by several balancing weights assigned to the crank mechanisms. Each of the crank mechanisms  4 . 1  and  4 . 2  of the vertical drive mechanism  3  has two balancing weights. A first balancing weight is arranged as counterweight on the crank mechanisms  4 . 1  and  4 . 2  and offset by an angle of 180° relative to eccentrics  6 . 1  and  6 . 2  of crankshafts  5 . 1  and  5 . 2 . The balancing weights are designed with the reference number  9 . 1  on the crank mechanism  4 . 1  and  9 . 3  on the crank mechanism  4 . 2 . A second balancing weight is offset by 90° relative to eccentrics  6 . 1  and  6 . 2  on crankshafts  5 . 1  and  5 . 2 . The balancing weights  9 . 2  and  9 . 4  of crank mechanisms  4 . 1  and  4 . 2  are then designed greater in weight than the balancing weights  9 . 1  and  9 . 3 . 
     The crank mechanisms  11 . 1  and  11 . 2  of the horizontal drive mechanism  10  each have a balancing weight  16 . 1  and  16 . 2 . The balancing weight  16 . 1  on crank mechanism  11 . 1  is offset at an angle &lt;180° relative to eccentric  13 . 1  and crankshaft  12 . 1 . The angle a that designates the offset between the eccentric  13 . 1  and the balancing weight  16 . 1  on the crankshaft  12 . 1  is about 20° in this practical example. The position of the balancing weight  16 . 1 , and also the position of the balancing weight  16 . 2  are essentially determined by the arrangement on the crank mechanisms  11 . 1  and  11 . 2  relative to each other. The connecting rods  14 . 1  and  14 . 2  are arranged in an oblique position and connected to each other via the double pivot joint  21 . The balancing weight  16 . 2  on crank mechanism  11 . 2  is therefore in the same position and with the same size on crank mechanism  11 . 2 . 
     To drive the needle beams  1 . 1  and  1 . 2 , both the crank mechanisms  4 . 1  and  4 . 2  of the vertical drive mechanism  3  and the crank mechanisms  11 . 1  and  11 . 2  of the horizontal drive mechanism  10  are driven synchronously and oppositely. A situation is shown in  FIG. 3.1 , in which the beam support  2  is held at top dead center with the needle beams  1 . 1  and  1 . 2 .  FIG. 3.2  shows the practical example in the operating situation, in which the beam support  2 , with the needle beams  1 . 1  and  1 . 2 , is in the middle position during execution of a horizontal movement. The inertial forces assigned to the balancing weights  9 . 1  to  9 . 4  and the balancing weights  16 . 1  and  16 . 2  are designated with the letters F A  and F B . 
     The four balancing forces F A1  to F A4  of the balancing weights  9 . 2 ,  9 . 4 ,  16 . 1  and  16 . 2  are compensated in the dead positions of beam support  2 , as is apparent from  FIG. 3.1 . The inertial forces F E1  and F E2 , caused by the balancing weights  9 . 1  to  9 . 4 , all run counter to the inertial force F B  engaging on beam support  2 . Because of the oblique position of the force components, a resulting inertial force remains between the dead positions. With appropriate choice of balancing weights  9 . 2 ,  9 . 4 ,  16 . 1  and  16 . 2 , the horizontal inertial force of the beam support with these force components with needle beams  1 . 1  and  1 . 2  is compensated in the horizontal direction. In the vertical direction, the balancing force is changed, especially at low adjustment angles and therefore oblique positions of the force components only slightly, so that force balancing for each horizontal stroke up to a maximum adjustment angle of about 20° is retained in very good approximation, as follows from the situation in  FIG. 3.2 . 
     However, it is also possible to design balancing for an adjustment angle that is different from zero. This means that the balancing weights on the crank mechanisms  11 . 1  and  11 . 2  of the horizontal drive mechanism  10  are mounted rotated by the angle a, so that the corresponding balancing forces are vertical at a corresponding adjustment angle. This means that the useful adjustment angle can be doubled without noticeable deviations occurring in vertical force balancing. The balancing weights  9 . 1  to  9 . 4  and the crank mechanisms  4 . 1  and  4 . 2  of the vertical drive mechanism  3  are adjusted in this case, so that for the region of horizontal stroke, the inertial forces are balanced in the vertical and horizontal direction. 
     In order to compensate for any form of free inertias occurring in addition to balancing of the inertial forces, the variant of the device according to the invention depicted in  FIGS. 3.1  and  3 . 2  can be made with a balancing device, in which a balancing shaft with a rotating concentric weight is provided, in addition to the balancing weights. This type of practical example is depicted in  FIG. 4 . 
     The practical example according to  FIG. 4  is identical to the practical example according to  FIG. 3.1 , except for the balancing device. To this extent, the previous description is referred to and only the differences are explained. 
     For weight balancing, the balancing device has several balancing weights, as well as a balancing shaft with rotating eccentric weight. The balancing shaft  22  is arranged in the drive plane between the crank mechanisms  11 . 1  and  11 . 2  of the horizontal drive mechanism  10 . The balancing shaft  22  extends parallel to the crankshafts  12 . 1  and  12 . 2  lying in the drive plane, which are also parallel to the crankshafts  5 . 1  and  5 . 2  of the vertical drive mechanism  3  arranged in the same plane. An eccentric weight  23  is arranged on the balancing shaft  22 . The balancing shaft  22  is driven synchronously with the crankshafts  12 . 1  and  12 . 2  of the crank mechanisms  11 . 1  and  11 . 2 , in which the balancing shaft  22  and the crankshaft  12 . 1  have the same direction of rotation. 
     For weight balancing, the balancing weights  16 . 1  and  16 . 2  are arranged on the crankshafts  12 . 1  and  12 . 2  of the crank mechanisms  11 . 1  and  11 . 2 . The arrangement is then identical to the previously described practical example according to  FIG. 3.1 . 
     The crank mechanisms  4 . 1  and  4 . 2  of the vertical drive mechanisms  3  are also assigned to balancing weights in offset arrangement. The balancing weights  9 . 1  and  9 . 2  are assigned to the crank mechanism  4 . 1  and the balancing weights  9 . 3  and  9 . 4  to the crank mechanism  4 . 2 . The balancing weights  9 . 1  to  9 . 4  of the crank mechanisms  4 . 1  and  4 . 2  are different in size. The balancing weight  9 . 2  arranged essentially to balance the horizontal inertial forces on the crank mechanism  4 . 1  is smaller than the balancing weight  9 . 4  on the second crank mechanism  4 . 2  of the vertical drive mechanism  3 . 
     Overall, in the situation depicted in  FIG. 4 , force equilibrium is produced between the forces generated by the balancing weights. The inertial force F M  of the eccentric weight  23  acts in the same direction as the inertial force F A4  of the balancing weight  16 . 2  on the crank mechanism  11 . 2 . The inertial forces F M  and F A4  are opposite the inertial forces F A1 , F A2  and F A3 . The vertical inertial force F B  acting on the beam support  2  is balanced by the balancing weights  9 . 1  to  9 . 4  arranged on the crank mechanisms  4 . 1  and  4 . 2  and their inertial forces F E1  and F E2 . 
     Another practical example of the device for needling of a fiber web is schematically depicted in  FIG. 5  in a side view. The practical example according to  FIG. 5  differs essentially from the aforementioned practical examples in that no separate or horizontal drive mechanisms present degenerate an overlapping horizontal movement of the needle beam. In the practical example depicted in  FIG. 5  of the device according to the invention, the superimposed horizontal movement of the needle beam is introduced via the vertical drive mechanism  3 . 
     For this purpose, the vertical drive mechanism connected to the beam support  2  has two parallel arranged crank mechanisms  4 . 1  and  4 . 2 . The crank mechanisms  4 . 1  and  4 . 2  have two parallel arranged crankshafts  5 . 1  and  5 . 2 , which are arranged above the beam support  2 . The crankshafts  5 . 1  and  5 . 2  each have at least one eccentric section to accommodate at least one connecting rod. The connecting rods  7 . 1  and  7 . 2  arranged on a beam support  2  are shown in  FIG. 5 , which are guided with their connecting rod small ends on the crankshafts  5 . 1  and  5 . 2 . 
     The crankshafts  5 . 1  and  5 . 2  are assigned a phase adjustment device  36 . The phase adjustment device  36  has two servo motors  34 . 1  and  34 . 2  assigned to the crankshafts  5 . 1  and  5 . 2 . The servo motors  34 . 1  and  34 . 2  are connected to a control device  35 . The servo motors  34 . 1  and  34 . 2  can be activated independently of each other by the control device  35 , in order to rotate the crankshafts  5 . 1  and  5 . 2  into their positions. The phase position between the two crankshafts  5 . 1  and  5 . 2  can therefore be adjusted. In addition to the pure vertical up-and-down movement of the beam support  2 , a superimposed horizontal movement can therefore be executed on the beam support  2 . During offset of the phase position of crankshafts  5 . 1  and  5 . 2 , an oblique position is introduced to the beam support  2  via the connecting rods  7 . 1  and  7 . 2 , which produces, during continuing movement, a movement component directed in the movement direction of a fiber web. The size of the phase adjustment between the crankshafts  5 . 1  and  5 . 2  is directly proportional to a stroke length of the horizontal movement. The stroke of the horizontal movement can therefore be adjusted via the phase angle of the crankshafts  5 . 1  and  5 . 2 . 
     In the situation depicted in  FIG. 5 , a phase difference is adjusted between crankshafts  5 . 1  and  5 . 2 , so that the beam support  2 , with needle beams  1 . 1  and  1 . 2 , executes a constant stroke in the horizontal direction. 
     To guide the beam support  2 , a guide device  27  is provided. The guide device has a linkage  19 , which is connected with one free end to the beam support  2  via a pivot joint  15 . On the opposite end of the linkage, a first rocker arm  28  engages, which is connected via a pivot bearing  32  to a machine frame and to the linkage via a pivot joint  30 . A second rocker arm  29  is provided at a spacing from the first rocker arm  28 , which is held in the middle area of the linkage  19  via a pivot joint  31  and via a pivot bearing  33 . 
     The guide device  27  is arranged above the beam support  2 . The pivot bearings  32  and  33  are arranged between the connecting rods  7 . 1  and  7 . 2 . The linkage  19  is connected in the beam center to the beam support via the pivot joint  15 . Secure guiding of the beam support during the drive movement by the vertical drive mechanism  3  can therefore be achieved. 
     The balancing device assigned to the crank mechanisms  4 . 1  and  4 . 2  is formed in this practical example by a total of four balancing weights  9 . 1 ,  9 . 2 ,  9 . 3  and  9 . 4 . The balancing weights  9 . 1  and  9 . 2  are assigned to the crankshaft  5 . 1 . The balancing weights  9 . 3  and  9 . 4  are fastened to the crankshaft  5 . 2 . The balancing weight  9 . 1  is offset on crankshaft  5 . 1  by an angle of 180° relative to eccentric  6 . 1 . The balancing weight  9 . 2  is offset by an angle of 90° relative to the first balancing weight  9 . 1  on crankshaft  5 . 1 . 
     The balancing weight  9 . 3  in the crank mechanism  4 . 2  is offset by 180° relative to the eccentric  6 . 2  on the crankshaft  5 . 2 . The balancing weight  9 . 4  is offset by an angle of 90° relative to the first balancing weight  9 . 3  on the crankshaft  5 . 2 . Both the vertical and horizontal inertial forces of the crank mechanisms  4 . 1  and  4 . 2  can therefore be advantageously balanced by the balancing weights  9 . 1  to  9 . 4 . 
     In order to achieve full balancing of the weighed and inertial forces, in particular, the balancing device additionally has a balancing shaft  22 , which is arranged around the crankshafts  5 . 1  and  5 . 2 . The balancing shaft  22  is held symmetric to the crank mechanisms  4 . 1  and  4 . 2 . Two eccentric weights  23 . 1  and  23 . 2  are arranged on the balancing shaft  22 . The balancing shaft  22  extends parallel to the crankshafts  5 . 1  and  5 . 2  and is driven synchronously with the crankshafts  5 . 1  and  5 . 2 . The direction of rotation of the balancing shaft  22  in the direction of rotation of the crankshafts  5 . 1  and  5 . 2  is marked by an arrow in  FIG. 5 . 
     The function for balancing of the inertial forces in operation of the device depicted in  FIG. 5  is identical to the aforementioned practical example, so that no further explanation occurs here. 
     The invention extends not only to the practical examples of a device for needling of a fiber web depicted in  FIGS. 1 ,  3  and  4 , but can also advantageously be used on other drive mechanism concepts, in which a needle beam is guided with constant horizontal stroke over variable horizontal strokes. The invention is particularly advantageous in those devices, in which the stroke adjustment of the horizontal stroke occurs by rotation of two eccentric shafts relative to each other. It is explicitly pointed out here that the invention is not restricted to the fact that crank mechanisms are driven by crankshafts. In principle, the crankshafts could be replaced without problem by eccentric shafts.