Abstract:
Rotary cutting apparatus has a frame, a first rotary device and a second rotary device. Each of the first and second rotary devices has a shaft concentrically arranged about a rotational axis and a drum and are arranged in the frame in such a way that said first and second axes are substantially horizontal and substantially in the same vertical plane. A pair of bearing housings is arranged on either side of each of the drums. A first pair of bearing housings is movable relative to the frame in a transverse direction to the first rotational axis by means of a force means. Means is provided for passive vibration attenuation of at least the first shaft that includes a mass damper having a housing and a damping body movably arranged inside the housing, wherein the mass damper is associated with the first pair of bearing housings.

Description:
RELATED APPLICATIONS 
       [0001]    This application is based on and claims priority under 37 U.S.C. §119 to Swedish Application No. 1150313-3, filed 8 Apr. 2011, the entire contents of which are incorporated herein by reference. 
       FIELD OF THE DISCLOSURE 
       [0002]    The present invention relates to a rotary cutting apparatus, comprising
       a frame;   a first rotary device, such as a rotary cutter or a rotary anvil comprising a first shaft concentrically arranged about a first rotational axis and a first drum, such as an anvil drum or a cutter drum concentrically arranged on said first shaft, said first shaft being provided with a first pair of bearing housings arranged on either sides of said first drum;   a second rotary device comprising a second shaft concentrically arranged about a second rotational axis, and a second drum, such as an anvil drum or a cutter drum concentrically arranged on said shaft, said second shaft being provided with a second pair of bearing housings arranged on either sides of said second drum;   said first and second rotary devices being arranged in said frame in such a way that said first and second axes are substantially horizontal and substantially in the same vertical plane;   said second shaft being connected to the frame via said second pair of bearing housings;   said first shaft being associated with said frame via said first pair of bearing housing, said first pair of bearing housings being movable relative to said frame in a transverse direction to said first rotational axis by means of a force means.       
 
       TECHNICAL BACKGROUND OF THE INVENTION 
       [0009]    In the discussion that follows, reference is made to certain structures and/or methods. However, the following references should not be construed as an admission that these structures and/or methods constitute prior art. Applicant expressly reserves the right to demonstrate that such structures and/or methods do not qualify as prior art against the present invention. 
         [0010]    A rotary cutting apparatus is known from EP-A-1 710 058. The known rotary cutting apparatus however suffers from the drawback that it is not adapted for high speed cutting. 
         [0011]    EP-A-1 721 712 discloses a rotary cutting apparatus provided with a controllable lifting device for actively lifting the anvil in response to a sensor for sensing protection of the anvil and the cutter against foreign bodies. 
         [0012]    EP-A-1 612 010 discloses an anvil drum and the cutter drum for a rotary cutting apparatus, the anvil drum and/or the cutter drum being divided into a peripheral sleeve and and an intermediate sleeve, the material of the latter being chosen depending on the desired properties, such as vibration damping, thermal insulation, thermal conduction, weight reduction or weight increase. 
         [0013]    WO 03/093696 discloses a mass damper for a machine tool intended for turning or milling. 
       SUMMARY OF THE INVENTION 
       [0014]    An object of the present invention is to improve the stability of the first and the second rotary devices of the rotary cutting apparatus, such that can be used for higher speeds. 
         [0015]    This has been achieved by a rotary cutting apparatus as initially defined, wherein means is provided for passive vibration attenuation of at least said first shaft, said means for passive vibration attenuation comprising a mass damper having a housing and a damping body movably arranged inside said housing, wherein said mass damper is associated with said first pair of bearing housings. 
         [0016]    Hereby is achieved that vibrations depending on e.g. the web to be cut will be dampened. The web is uneven in its contents and structure and thus causes a more or less continuous vibration. Furthermore, the web may contain large debris of a size larger than that of the thickness of the web, or undesired items like tools may fall onto the web. Either of them may cause an impact, in turn causing a sudden movement of the first shaft, resulting in a transient in the vibration pattern. Consequently, a possibility of quickly damping strong transients, due to impacts by e.g. foreign objects on or inside the web is achieved by means of said mass damper. 
         [0017]    Furthermore, the life time of the anvil and the cutting edge will be extended. 
         [0018]    Yet furthermore, the relative displacements (other than rotational movement) between the rotary anvil and the rotary cutter will be reduced, resulting in an improved cut of the article from the web. 
         [0019]    Suitably, said housing has the shape of an elongated cylinder with circular cross-section, said housing being provided with a rod or a tubing, said rod or tubing being concentrically arranged inside said housing by means of at least one bushing. 
         [0020]    Preferably, said bushing connects the rod or tubing to said housing in such a way that a space is created between said rod or tubing and housing, the space comprising said damping body. 
         [0021]    Suitably, said damping body comprises a plastic material and/or a metallic material. 
         [0022]    Preferably, said damping body is substantially prevented from moving in an axial direction inside said housing, and wherein said damping body is allowed to move in a radial direction in relation to said rod or tubing inside the housing. 
         [0023]    Suitably, said housing comprises a fluid, such as a liquid or a gas. In particular, said fluid is one of or a combination of air, water, oil and grease. 
         [0024]    Preferably, said elongated housing is arranged parallel to said first rotational axis. Alternatively, said elongated housing is arranged transversely to said first rotational axis. In particular, one housing is arranged on either sides of said first drum. 
         [0025]    Suitably, said first rotary device comprises a rotary anvil and said second rotary device comprises a rotary cutter. 
     
    
     
       DRAWING SUMMARY 
         [0026]    In the following, preferred embodiments of the invention will be described in further detail with reference to the accompanying drawings, in which 
           [0027]      FIG. 1A  is a front perspective view of a rotary cutting apparatus according to a first embodiment of the invention having cutter drum and an anvil drum. 
           [0028]      FIG. 1B  is a front perspective view of the rotary cutting apparatus shown in  FIG. 1A , including a mass damper, parts of the frame being omitted. 
           [0029]      FIG. 1C  is a rear perspective view of the rotary cutting apparatus shown in  FIG. 1A , parts of the frame being omitted. 
           [0030]      FIG. 2  is a front perspective view of a rotary cutting apparatus according to an alternative aspect of the invention including a mass damper. 
           [0031]      FIG. 3  is a front perspective view of a rotary cutting apparatus according to a further aspect of the invention. 
           [0032]      FIG. 4  is an anvil drum as shown in  FIGS. 1A-1C  and  FIGS. 2-3 , partly with details omitted, partly in cross-section. 
           [0033]      FIG. 5  is a front perspective view of a rotary cutting apparatus according to a further aspect of the invention. 
           [0034]      FIGS. 6   a  and  6   b  is a schematic view of a web cut to articles by the cutting apparatus shown in  FIGS. 1 to 5 . 
           [0035]      FIG. 7  illustrates schematically the principle of the mass damper shown in  FIGS. 1B and 2 . 
       
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0036]      FIGS. 1A-1C  show a rotary cutting apparatus  2  comprising a frame  4  adapted to be attached to a not-shown basement. In the frame  4 , a rotary cutter  6  and a rotary anvil  8  are arranged. In  FIG. 1A , the rotary cutter  6  and the rotary anvil  8  are shown in a cutting relationship, whereas in  FIGS. 1B  and  FIG. 1D , they are shown in a separated relationship. 
         [0037]    The rotary cutter  6  is provided with an elongated cutter shaft  10  and a cutter drum  12 , the cutter drum  12  being coaxially arranged on the cutter shaft  10  about a rotation axis A-A. The shaft has an axial extension on each side of the cutter drum  12 , where a cutter bearing housing  14  is provided, respectively. The cutter bearing housings  14  are each connected to the frame  4  by means of a fastening element  16 , such as a screw. The cutter shaft  10  is preferably made of steel and is adapted to connected to a not shown rotatable power source. 
         [0038]    The cutter drum  12  is provided with a pair of annular support rings  17  and a pair of annular cutter sleeves  18   a,    18   b  each provided with cutting members  20  for cutting articles from a web (see  FIG. 6 .). The support rings  17  may be separate parts. Alternatively, one of the support rings may be an integrated part of the cutter sleeve  18   a  and the other support ring an integrated part of the other cutter sleeve  18   b.  An intermediate annular sleeve  22  without cutting edges is provided between the annular cutter regions  18   a,    18   b,  the intermediate sleeve  22  and the cutter sleeve  18   a,    18   b  being coaxially arranged in relation to the axis A-A. Alternatively, the support rings  17 , the annular cutting sleeves  18   a,    18   b  and the intermediate annular sleeve  22  may be made of one single piece, forming a an integrated annular sleeve, the axial extension of which corresponding to that of the cutter drum  12 . 
         [0039]    The support rings  17 , the annular cutter sleeves  18   a,    18   b  and/or the intermediate piece may be made of steel, but are preferably made of a cemented carbide. They are press-fit onto a portion of the cutter shaft  10  having an enlarged diameter, altogether constituting said cutter drum  12 . 
         [0040]    The rotary anvil  8  is provided with an elongated anvil shaft  24  and an anvil drum  26 , the anvil drum  26  being coaxially arranged on the anvil shaft  24  about a rotation axis B-B. 
         [0041]    The anvil drum  26  comprises a pair of support rings  27  and three coaxially arranged annular anvil sleeves  28   a,    28   b,    28   c,  each having a rotational symmetrical anvil surface  29 , coaxial to the axis B-B. 
         [0042]    The support rings  27  may be separate parts. Alternatively, one of the support rings may be an integrated part of the peripheral anvil sleeve  28   a  and the other support ring an integrated part of the other peripheral anvil sleeve  28   c.  The peripheral anvil sleeves  28   a,    28   c  are arranged on either sides of the anvil sleeve  28   b.  Together, they are coaxially arranged in relation to the rotational axis B-B and are preferably made of steel. Alternatively, the peripheral sleeves  28   a,    28   c,  the intermediate sleeve  28   b  and the support rings  27  are made as a single piece, forming an integrated annular sleeve, the axial extension of which corresponding to that of the cutter drum anvil drum  26 . 
         [0043]    They are press-fit onto a portion of the anvil shaft  24  having an enlarged diameter, altogether constituting said anvil drum  26  (see also  FIG. 4 ). 
         [0044]    The support rings  27  are adapted to bear against the support rings  17  of the cutter drum during the cutting operation. 
         [0045]    The anvil shaft  24  is arranged vertically above the cutter shaft  10  in such a way that the axis B-B is parallel to and is in the same vertical plane as the axis A-A. 
         [0046]    An anvil bearing housing  30  is arranged on either sides of the anvil drum  26  and connected to an intermediate piece  32  (best shown in  FIG. 1B ). The intermediate piece  32  is in sliding relationship with a pair of C-shaped parts  34  of the frame  4 , having an upper shank  34   a,  a lower shank  34   b  and an interconnecting portion  34   c,  via four guide members  36 . The C-shaped part  34  is provided with an opening  37  for allowing access to the anvil bearing housing  30 , two of the guide members  36  being arranged between the upper and lower shanks  34   a,    34   b  and on opposite sides of one of the anvil bearing housings  30 , while two further guide members are arranged between the upper and lower shanks  34   a,    34   b  and on opposite sides of the other anvil bearing housing  30 . 
         [0047]    A pair of pneumatic cylinders  38  are each provided with a piston  40  (best shown in  FIG. 1C ) and a hose  42  for connection to a not shown pneumatic source. During operation, the piston will press the intermediate piece  32  including the anvil bearing housings  30  and thus also the anvil support ring  27  as well as the surface of the annular anvil rings  28   a,    28   c  towards and against the support rings  17  and the cutting members  20  of the cutter drum, respectively. 
         [0048]    A helical spring  44  is provided about each guide member  36  and acting on the intermediate piece  32  and the  34   b  lower shank of the C-shaped part  34 . Hereby, the anvil drum  26  is prevented from colliding with the cutter drum  12  when applying pressure by means of the pneumatic cylinders or after passage of a foreign body, in turn avoiding damages of the knife member  20  and/or the anvil surface  29 . The springs  44  also counter-balance the weight of the rotary anvil  8 , such that a minimum pressure is required for the anvil surface  29  to come into contact with the cutting members  20  during use. 
         [0049]    Between the intermediate piece  32  on each side of the anvil drum  26 , a passive damper  46  in the form of a mass damper  47  comprising an elongated cylinder  48  is arranged parallel to the rotational axis B-B of the anvil drum  26 . The cylinder  48  is connected to the intermediate pieces  32  by brackets  49 , respectively. The elongated cylinder  48  comprises a movable damping body  50 , tunable to a predetermined frequency range. 
         [0050]    A further passive damper  46  in the form of the members  52  shown as circular-cylindrical tubes and made of any elastomeric material having a high damping coefficient, such as polyurethane (PU), rubber, silicone or neoprene. Each elastomeric member is are arranged about one of the helical springs  44  and thus also about one of the guide members  36 , as can be understood by the cross-section-in-part of  FIG. 1B . 
         [0051]    The elastomeric members  52  also adds to the stiffness of the rotary cutting apparatus  2 , adding to the stability of thereof. 
         [0052]    The elastomeric members  52  will isolate the anvil drum  26  from the vibrations transferred via the frame from the web or the source of power. 
         [0053]    As already mentioned above,  FIG. 1A  shows how the rotary cutter  6  and the rotary anvil  8  come into a cutting relationship by allowing the pneumatic cylinders  38  to press against an upper contact surface  54  of the intermediate piece and in turn on the rotary anvil. 
         [0054]    In  FIGS. 1B and 1C  the pneumatic cylinders  38  have been de-activated, such that no pressure is any longer exerted by them downwardly on the intermediate pieces  32 . Instead, the springs  44  exert a pressure upwardly on the lower shank  34   b  of the C-shaped portion  34  and on a lower contact surface  56  of the intermediate piece  32 . The springs  44  will thus cause the rotary anvil  8  to move vertically upwards and away from the rotary cutter  6  to the above mentioned non-cutting, in this case lifted position. 
         [0055]    When the anvil drum  26  is in a cutting relationship with the cutter drum  12 , the elastomeric members  52  (see  FIG. 1B ) will each contact the lower shank  34   b  of the C-shaped parts  34  as well as the lower contact surface  56  of the intermediate piece  32 . However, when the pneumatic cylinders  38  are inactivated, the springs  44  will press the intermediate piece  32  vertically upwards such that the upper contact surface  54  of the intermediate piece  32  will rest against the upper shank  34   a  of the C-shaped part  34 . There will be a free space between the elastomeric member  52  and the lower contact surface  56  of the intermediate piece, since the elastomeric member  52  has a shorter axial extension than the spring  44 . 
         [0056]    In order to lower the centre of gravity, the intermediate piece  32  is made of a light material, such as aluminium. Also other parts arranged at a high point influencing the centre of gravity should be made of a light material, such that it can be lowered. 
         [0057]    In  FIG. 1C  is also shown a guide roller  60  for a web  68  (see also  FIG. 6 ), as well as moisturizing rollers  62  for applying oil on the cutting members  20 .  FIG. 2  shows a second embodiment of the invention, according to which a pair of passive dampers  46  in the form of elongated cylinders  48  are connected to each intermediate piece  32  by retainers  61 . The elongation of the cylinders  48  are in this case across the rotational axis B-B of said anvil. 
         [0058]    Also in this case, the elongated cylinders  48  are mass dampers  47 . No further passive damper in the form of circular-cylindrical rings is provided. 
         [0059]    As described above, the springs  44  act in cooperation with the pneumatic cylinders  38 . As can be seen in  FIG. 2 , the anvil drum  26  is in its non-cutting, also in this case lifted position. 
         [0060]    Depending on the vibration damping requirements, the mass dampers  47  of  FIG. 2  could be combined with further passive dampers in the form of elastomeric rings  44  as shown in  FIGS. 1A-1C . 
         [0061]      FIG. 3  shows a third embodiment, according to which passive dampers in the form of elastomeric rings are provided about the springs. The springs are visible, sine the anvil drum  26  is in its non-cutting, also in this case lifted position. No mass damper is provided. 
         [0062]      FIG. 4  shows the rotary anvil  26  of  FIGS. 1A-1C ,  2  and  3  with its anvil shaft  24  and anvil sleeves  28   a,    28   b,    28   c  (the anvil sleeve  28   a  being omitted in the figure for facilitating understanding). 
         [0063]    In order to reduce vibrations in the rotary cutting apparatus  38 , it is preferred that the centre of gravity of the rotary cutting apparatus  2  is as low as possible. 
         [0064]    As can be seen in the figure, the anvil shaft has a larger radial extension than that of the opposite ends, where the bearing housings are to be arranged. Consequently, in order to reduce weight of the rotary anvil mounted above the rotary cutter  6 , radial blind holes  64  are provided in the anvil shaft  24  under the anvil sleeves  28   a,    28   c.  For the same purpose, a ring-shaped groove  66  is provided underneath the anvil sleeve  28   b,  hereby reducing of the diameter of the anvil shaft  24 . It should be noted that the radial blind holes  64  and/or the groove should be large enough to create a substantial weight reduction. 
         [0065]    It should be noted that the centre of gravity may be lowered by choice of material of relatively heavy parts, e.g. of the intermediate part  32  shown in  FIGS. 1A-1C  and  2 - 3 , to aluminium, carbon fibre or the like, instead of steel. 
         [0066]      FIG. 5  shows a fourth embodiment, according to which the rotary cutter  6  with knife members  20  is arranged vertically above the rotary anvil  8 . As described above, the anvil shaft  24  is connected via the anvil bearing housings  30  to the intermediate piece  32 , which is movably arranged in relation to guide members  36 . The pneumatic cylinders  38  are arranged below the rotary anvil  8  and thus press the anvil drum  26  upwards towards and against the cutter drum  12  to a cutting position. When the pneumatic cylinders  38  are inactivated, the springs will press the anvil drum  26  downwards to a non-cutting, in this case lowered position (not shown). In order to lower the centre of gravity, the extension of the cutter shaft  10  may be reduced such that it does not extend outside one of the cutter bearing housing  14 , the other extension being connected to a not shown power source. 
         [0067]    In this embodiment, the cutter shaft  10  may instead of the anvil shaft  24  be provided with the weight reduction as explained in connection with  FIG. 4 , since this will lower the centre of gravity of the rotary cutting apparatus  2 . Preferably, the intermediate piece  32  should in this case be made of steel, since the low position of it would in itself lower the centre of gravity. 
         [0068]    In  FIG. 6A , the anvil drum  26  is arranged above the cutter drum  12 , whereas in  FIG. 6B , the cutter drum is arranged above the anvil drum.  FIGS. 6A and 6B  show schematically how a web  68  is conveyed via the nip  69  between the cutter drum  12  and the anvil drum  26 , being in a cutting relationship, and how the cut articles are directed in another direction than what is the case for the residue of the web, and depending on which one of the drums is arranged on top of the other. 
         [0069]      FIG. 7  shows schematically the principle of the mass damper  47  shown in  FIGS. 1B and 2 . 
         [0070]    In the mass damper  47  of  FIG. 7 , an elongated circular cylindrical housing  48  is concentrically provided with a rod or a tubing  70 . The housing is  48  connected to the rod or tubing  70  by means of a bushing  72 , preferably made of an elastomeric material, such that disassembly is allowed. A space  74  is defined between the housing and the rod. In the space, there is provided a damping body  50  made of e.g. plastic, steel or led. The damping body  50  is substantially prevented from moving in an axial direction by the bushings  72 . The damping body  50  is however allowed to move in a radial direction in relation to said rod or tubing  70  inside the housing  48 . The remaining space is filled with a fluid, such as air, water, oil or grease. 
         [0071]    The mass damper  50  may instead be constituted by a liquid of high density, such as mercury. Alternatively, the damping body may be comprise granules of a suitable material such as led, optionally combined with a fluid (cf. above) 
         [0072]    The mass damper  47  is possible to tune for different frequency ranges by choosing the length and diameter of the damping body  50  or the number of mass dampers  47 , by choosing material of the damping body and by choosing what kind of gas or liquid is filled in the remaining space inside the housing. 
       Operation 
       [0073]    A cutting operation as shown in  FIGS. 6A and 6B  has commenced. 
         [0074]    Vibrations will be caused due to unbalances in the rotary cutter  6  and/or rotary anvil  8 . 
         [0075]    The web  68 , is in itself relatively uneven as seen in a transverse direction of the web  68 . This is because the contents of the web itself is a a combination of layers of varying thickness of i.a. fibres and super-gel. When passing the nip  69 , a vertical movement of the rotary anvil  8  is caused. The larger the vertical movement, the larger the amplitude of the vibration. Due to the varying thickness of the web, continuous vibrations will be created when the web passes the nip  69 . 
         [0076]    In order to reduce the influence of continuous vibrations, it is important to lower the static and dynamic response and in particular to raise or lower the eigenfrequency by a proper design of the rotary cutting apparatus  2  including the frame  4 , e.g. by choice of dimensions and material of different parts. 
         [0077]    The springs  44  as such will add to the the stiffness of the frame and consequently move the eigenfrequencies to a desired frequency. 
         [0078]    Continuous vibrations will be possible to reduce by lowering the centre of gravity of the rotary cutting apparatus, e.g. as discussed in connection with  FIG. 4 . 
         [0079]    A foreign body inside or on the web causes the rotary anvil  8  to move vertically away from the cutting relationship with the rotary cutter even more. When the foreign body has passed the nip  69 , the anvil drum  26  will be pressed towards the cutter drum  12  by the force of the pneumatic cylinders  38 , possibly causing an impact. The springs  44  will reduce the return force of the impact, but they cannot reduce the vibrations due to the impact. For this reason, the passive dampers  46  as described above are provided. 
         [0080]    The passive dampers  46  in the form of elastomeric members  52  will instantaneously reduce the force of the impact due to the circular cylindrical shape, and the choice of material will add to the reduction of the vibrations caused by the impact. 
         [0081]    In the figures the elastic members have been shown as shorter than the axial elongation of the springs  44 . They may however be longer than the helical springs. 
         [0082]    The passive dampers  46  in the form of one or more mass dampers  47  will not be able to reduce the impact as such, but tests have proven that they will very efficiently and quickly reduce the vibrations caused by impacts. 
         [0083]    The claims are not restricted to the embodiments shown above. Accordingly, depending on the vibration damping requirements, the mass dampers and of  FIG. 2  could be combined with further dampers in the form of elastomeric rings as shown in  FIGS. 1A-1C . For the same reason, the elastomeric rings shown in  FIGS. 1A-1C  may be omitted. 
         [0084]    The housing  48  of the mass damper  47  may have any suitable shape, the cylinder having a cross-section being e.g. square, rectangular, triangular, polygonal or oval, the damping body  50  being adapted to the selected shape. Furthermore, the housing may have a non-cylindrical shape. 
         [0085]    Likewise, even though the mass damper  47  of  FIG. 5  has been shown as being solely of the cylindrical kind arranged parallel to the rotational axis B-B of the anvil drum, it could be replaced by the mass dampers  47  across the rotational axis B-B, as shown in  FIG. 2 , be exchanged to the elastometric rings as shown in  FIG. 3  or be constituted by a combination of the dampers, depending on the damping requirements. 
         [0086]    The pneumatic cylinders  38  may instead be hydraulic. The intermediate sleeve  22  shown in  FIG. 1A  may be constitutes by a further cutter sleeve. On the other hand, the cutter sleeves  18   a,    18   b  and the intermediate sleeve  22  may be constituted by a single cutter sleeve. 
         [0087]    The support rings  17  of the cutter drum  12  are described above as bearing against the support rings  27  of the anvil drum  26 . It should however be noted that the anvil drum  26  may not be provided with support rings  27  at all, such that the support rings  17  of the cutter drum will bear directly against the anvil drum  26 . Likewise, the cutter drum  12  may not be provided with the support rings  17  at all, such that the support rings of the anvil drum will bear directly against the cutter drum  12 . 
         [0088]    The springs  44  have been shown in the figures as helical springs. It should however be understood that any kind of resilient means having a spring action is meant. 
         [0089]    The passive damper  46  in the form of four elastomeric members  52  may be made of any suitable damping material and may have any shape, such as a cylinder with a square shape or another polygonal shape. Likewise, the cylindrical shape may instead have the shape of a cone or a truncated cone or even spherical. It may be solid or hollow, depending on whether it is to be arranged about the spring  44  or beside it. The number is also not restricted to four, but could be two, three, or five or more, depending on the desired properties. 
         [0090]    Even though it has been described above that the rotary anvil  8  is vertically movable in relation to the frame  4 , it should be understood that the rotary cutter  6  may instead be vertically movable in relation to the frame. In that case, the cutter bearing housings  14  of the cutter shaft  10  will be connected to the intermediate piece  32 , movably arranged at the guide members  36 , while the anvil bearing housings  30  of the anvil shaft  24  will be connected to the frame  4 . This relates to the both the upper (see  FIGS. 1A-1C ,  2  and  3 ) and the lower arrangement (see  FIG. 5 ) of the intermediate piece  32 . 
         [0091]    In the embodiment of  FIG. 5 , where the anvil drum is arranged underneath the cutter drum, the anvil drum may be made in one piece together with the shaft. 
         [0092]    Although the present invention has been described in connection with preferred embodiments thereof, it will be appreciated by those skilled in the art that additions, deletions, modifications, and substitutions not specifically described may be made without department from the spirit and scope of the invention as defined in the appended claims 
       LIST OF REFERENCE NUMERALS 
       [0000]    
       
           2  rotary cutting apparatus 
           4  frame 
           6  rotary cutter 
           8  rotary anvil 
           10  cutter shaft 
           12  cutter drum 
           14  cutter bearing housings 
           16  fastening element 
           17  support ring 
           18   a,    18   b  annular cutter sleeve 
           20  cutting members 
           22  intermediate annular sleeve 
           24  anvil shaft 
           26  anvil drum 
           27  support rings 
           28   a,    28   b,    28   c  annular anvil sleeve 
           29  anvil surface 
           30  anvil bearing housing 
           32  intermediate piece 
           34  C-shaped part 
           34   a  upper shank 
           34   b  lower shank 
           34   c  interconnecting portion 
           36  guide member 
           37  opening 
           38  pneumatic cylinder 
           40  piston 
           42  hose 
           44  spring 
           46  passive damper 
           47  mass damper 
           48  elongated cylinder 
           49  bracket 
           50  damping body 
           52  elastomeric member 
           54  upper contact surface 
           56  lower contact surface 
           60  guide roller 
           61  retainer 
           62  moisturizing roller 
           64  radial bore 
           66  groove 
           68  web 
           69  nip 
           70  rod or tubing 
           72  bushing 
           74  space