Abstract:
In order to so improve a cutting machine comprising a machine frame, an anvil roller rotatable on the machine frame about an axis of rotation and having an anvil surface, a cutting tool mounted on the machine frame for rotation about an axis of rotation, with a cutter interacting with the anvil surface and with supporting rings which are held on the cutting tool and support it relative to the anvil roller with their supporting ring surfaces and/or vice versa, that the quality of the cutting effect can be maintained even when the cutter becomes worn, it is proposed that the diameter of the supporting ring surface of each supporting ring be adjustable by radial stretching of the supporting ring within the range below an elastic expansion limit of its material by means of an expansion device.

Description:
[0001]    The present disclosure relates to the subject matter disclosed in German application No. 100 40 024.8 of Aug. 16, 2000, which is incorporated herein by reference in its entirety and for all purposes.  
         BACKGROUND OF THE INVENTION  
         [0002]    The invention relates to a cutting machine comprising a machine frame, an anvil roller rotatably mounted on the machine frame about a rotary axis and having an anvil surface, a cutting tool mounted on the machine frame for rotation about a rotary axis, with a cutter interacting with the anvil surface and with supporting rings which are held on the cutting tool and support it relative to the anvil roller with their supporting ring surfaces and/or vice versa.  
           [0003]    A cutting machine of this type is known e.g. from German patent application 198 34 104.0.  
           [0004]    The problem with such cutting machines is that the cutter itself wears down in the course of time, and even slight wear on it may lead to an inadequate cutting effect with sensitive webs of material.  
           [0005]    The object underlying the invention is therefore to improve a cutting machine of the generic type so that the quality of the cutting effect can be maintained even when the cutter becomes worn.  
         SUMMARY OF THE INVENTION  
         [0006]    In a cutting machine of the above type this object is solved, according to the invention, in that the diameter of the surface of each supporting ring is adjustable by radial stretching of the supporting ring within the range below an elastic expansion limit of its material by means of an expansion device.  
           [0007]    The advantage of the solution according to the invention is thus that the possibility has been created of making the diameter of the supporting ring surfaces variable, as a means of allowing for changes in the radial extent of the cutter and particularly for wear on it.  
           [0008]    In the solution according to the invention, initially with a new, i.e. unworn cutter, the supporting ring is stretched to the maximum, though still within the range below its elastic expansion limit, so that the supporting ring surface has its maximum diameter. When the cutter becomes worn the expansion can be reduced by the adjustable expansion device; as the stretch is within the range below the elastic expansion limit of the supporting ring, that ring contracts automatically through its elastic action when the expansion device is reset to less expansion, and the diameter of the supporting ring surface can thus be reduced according to the wear on the cutter.  
           [0009]    The solution according to the invention may therefore have the expansible supporting rings according to the invention on the cutting tool or on the anvil roller or on both; in the latter case a supporting ring on the cutting tool and a corresponding supporting ring on the anvil roller will have their surfaces in contact, so that twice the adjustment range can be obtained.  
           [0010]    The expansion device might for example operate hydraulically, comprising e.g. hydraulically actuated clamping jaws. A particularly favorable solution is for the device to have interacting wedge surfaces which are adjustable in their position relative to each other, in order to expand the supporting ring adjustably by stretching.  
           [0011]    The wedge surfaces might e.g. be simple (flat) surfaces, in which case the supporting ring could be stretched evenly by a plurality of wedge surfaces.  
           [0012]    A particularly favorable solution provides for at least one of the wedge surfaces to be in the form of a conical surface relative to the rotary axis. A conical surface of this type allows particularly uniform stretching of the supporting ring.  
           [0013]    However it is particularly beneficial for both wedge surfaces to be in the form of conical surfaces relative to the rotary axis, in order to stretch the supporting ring as evenly as possible and especially to obtain uniform radial rigidity for the support between the cutting tool and anvil roller.  
           [0014]    In a particularly favorable solution in respect of adjustability, one of the wedge surfaces is an internal one and the other is a corresponding external one, and they are movable relative to each other in a direction parallel with the rotary axis to adjust the expansion of the supporting ring.  
           [0015]    A particularly appropriate way of adjusting the expansion with the expansion device is for an internal wedge surface to be arranged on a radially expansible element carrying it; that element allows the supporting ring to be supported radially in a simple manner.  
           [0016]    A particularly appropriate solution provides that, in all diameter adjustments of the supporting ring surfaces the internal wedge surface is seated on the external wedge surface with elastic expansion of the element carrying the internal surface, so that the expansion device operating with the wedge surfaces does not allow any play or radially reduced rigidity through the superimposed wedge surfaces, which would have a negative effect on the support between the cutting tool and the anvil roller.  
           [0017]    In an advantageous embodiment the external wedge surface is provided on an expansion member arranged on the cutting tool or the anvil roller; this expansion member may be either part of the cutting tool or the anvil roller or may be a separate part placed on and supported against the cutting tool or anvil roller.  
           [0018]    The expansion member could itself have a certain radial elasticity. In order to obtain defined expansion of the supporting ring it is however advantageous for the expansion member to be substantially non-elastic in a radial direction.  
           [0019]    Particularly simple adjustment of radial expansion can be obtained if the radially expansible element carrying the internal wedge surface and the expansion member are movable relative to each other in the direction of the rotary axis, so that the required amount of expansion can be set.  
           [0020]    It is particularly beneficial if the radially expansible element carrying the internal wedge surface and the expansion member may be fixed in the various positions relative to each other on the cutting tool or on the anvil roller.  
           [0021]    Especially simple adjustability can be obtained if the radially expansible element and the expansion member may be positioned varying distances away from an end face of the cutting tool or the anvil roller, in order to hold these in the required position relative to each other which predetermines the expansion.  
           [0022]    This can be engineered particularly appropriately if the radially expansible element or the expansion member may be positioned by a distance element different distances away from the end face of the cutting tool or on the anvil roller, so that the necessary relative positioning of the expansion member and radially expansible element can be defined in a simple manner.  
           [0023]    It would be possible to construct the expansion device with an expansion member and a radially expansible element provided, these parts then interacting to stretch the supporting ring in a radial direction.  
           [0024]    A structurally particularly simple and hence cost-effective solution is for the radially expansible element to be the supporting ring itself, so that the supporting ring itself is part of the expansion device provided that the ring carries the internal wedge surface.  
           [0025]    In a structurally especially simple embodiment the external wedge surface is seated on a central expansion member which is surrounded by the supporting ring.  
           [0026]    To obtain easy adjustability of the stretch but also stable fixing of the supporting ring on the cutting tool, the supporting ring may be braced against an end face of the cutting tool or of the anvil roller, in order not only to brace the supporting ring in a radial direction but also to put it in a defined position in a plane perpendicular to the rotary axis, thus achieving extremely precise bracing of the cutting tool and anvil roller relative to each other.  
           [0027]    The solution according to the invention can be obtained particularly easily if the supporting ring can be positioned against the cutting tool an adjustable distance away from the end face of the cutting tool or anvil roller according to the elastic expansion state.  
           [0028]    It is particularly appropriate if the supporting ring can be positioned various distances away from the end face by the distance element, as clamping is then still possible, enabling the supporting ring to be held securely to the cutting tool or anvil roller.  
           [0029]    In addition the above-mentioned object can be solved according to the invention by a cutting tool rotatable about a rotary axis, with a cutter which interacts with an anvil surface of an anvil roller rotatable about a rotary axis, and with supporting rings which are held to the cutting tool and support it relative to the anvil roller with their supporting ring surfaces, in that in the case of each supporting ring the diameter of the supporting ring surface is adjustable by radial expansion of the supporting ring within the range below an elastic expansion limit of its material, by means of an expansion device.  
           [0030]    The above-mentioned object can further be solved according to the invention by an anvil roller rotatable about a rotary axis, comprising an anvil surface which interacts with a cutter of a cutting tool rotatable about a rotary axis, and further comprising supporting rings which are held to the anvil roller and support it relative to the cutting tool with their supporting ring surfaces, in that in the case of each supporting ring the diameter of the supporting ring surface is adjustable by radial expansion of the supporting ring within the range below an elastic expansion limit of its material, by means of an expansion device. 
       
    
    
       [0031]    Other features and advantages of the invention are the subject of the following description and of the drawings of an embodiment.  
       BRIEF DESCRIPTION OF THE DRAWINGS  
       [0032]    [0032]FIG. 1 is a vertical section through a cutting machine according to the invention taken along line  1 - 1  in FIG. 2;  
         [0033]    [0033]FIG. 2 is a vertical section taken along line  2 - 2  in FIG. 1;  
         [0034]    [0034]FIG. 3 is a larger-scale representation of the anvil roller and cutting tool in FIG. 2;  
         [0035]    [0035]FIG. 4 is a plan view of a cutting tool in the direction of arrow A in FIG. 2;  
         [0036]    [0036]FIG. 5 is a section taken along line  5 - 5  in FIG. 4 with the supporting ring stretched to the maximum;  
         [0037]    [0037]FIG. 6 is a section similar to FIG. 5 with the stretching of the supporting ring reduced by moving it away from an end face of the cutting tool, and  
         [0038]    [0038]FIG. 7 is a section similar to FIG. 5 with the stretching of the supporting ring reduced, and with the ring simultaneously fixed to the end face of the cutting tool by a distance element. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0039]    A cutting machine according to the invention, shown in respective sections in FIGS. 1 and 2, comprises a machine frame referred to generally as  10  and having two spaced bearing members  12  and  14 .  
         [0040]    Each bearing member, e.g. member  12  in FIG. 1, comprises two side mounts  16  and  18  with a lower bearing mount  20  and an upper bearing mount  22  arranged between them.  
         [0041]    The lower bearing mount  20  is on the one hand located between the side mounts  16  and  18  and on the other hand seated securely on a base plate  24  of the machine frame  10 . The mount  20  has a bearing receiver  26  in which the outer race  30  of a lower pivot bearing referred to generally as  28  is inserted, the outer peripheral side of the race  30  lying against an internal surface of the receiver  26 . The race  30  is fixed in the receiver  26  by an external retaining member  32  and an internal retaining member  34 ; these have retaining rings  36  and  38  which lie against lateral annular surfaces of the external race  30  and thus fix it in the receiver  26 . In addition the external retaining member  32  has a cover  40 .  
         [0042]    The upper bearing mount  22  is located between the side mounts  16  and  18  and arranged displaceably in a direction  42  parallel with that in which the mounts  16  and  18  extend, in the direction of the lower bearing mount  20 . The upper mount  22  also has a bearing receiver  46  in which an upper pivot bearing  48  is inserted.  
         [0043]    The outer race  50  of the upper pivot bearing  48  is held in and against the bearing receiver  46  in the same way as the outer race  30  of the lower pivot bearing  28 , and an external retaining member  32  and an internal retaining member  34  are also provided; these are in the same form as the retaining members provided in the lower bearing mount  20 , and they fix the outer race  50  of the upper bearing  48  in the same way.  
         [0044]    The upper bearing mount  22  is itself supported by a biasing means referred to generally as  60 , against an abutment  62  which is held on an upper plate  64  extending parallel with the base plate  24 ; the upper plate  64  also connects the bearing members  12  and  14  and fixes the side mounts  16  and  18  relative to each other.  
         [0045]    Bearing member  14  is in the same form as bearing member  12 .  
         [0046]    A shaft stub  72  is mounted in each of the two lower pivot bearings  28 ; the stubs  72  project laterally from an anvil roller referred to generally as  70  and are arranged concentrically with a rotary axis  74  of the roller  70 , which has a larger radius than the shaft stub  72  and is provided with a circular cylindrical anvil surface  76  arranged coaxially with the axis  74 .  
         [0047]    The two lower pivot bearings  28  thus support the anvil roller  70  securely in the lower bearing mounts  20 , which in turn rest on the base plate  24  and are located between the side mounts  16  and  18 .  
         [0048]    In the upper pivot bearings  48  of the upper bearing mount  22  a cutting tool  80  which is driven in rotation and which has a tool shaft  82  is mounted for rotation about an axis  84 ; the tool shaft  82  for example extends through the bearing member  12  and has a drive stub  86  projecting beyond the member  12  at the side opposite its rotating cutting tool  80 ; the stub  86  provides a rotary drive for the rotating cutting tool  80  by means of a drive, e.g. a motor.  
         [0049]    The rotating cutting tool  80  is movable in the direction of the anvil roller  70  owing to the arrangement of the upper pivot bearings  48  in the upper bearing mounts  22  and their displaceability in direction  42 . With the aid of the biasing means  60  which act on the upper bearing mounts  22  the rotating cutting tool  80  may be biased in the direction of the anvil roller  70 , in such a way that the tool as an entity acts on the roller  70  with a biasing force V.  
         [0050]    The rotating cutting tool  80  has cutters  92  for severing a web  90  of material, referred to generally as  90  and passed through between the rotating tool  80  and the anvil roller  70 ; the cutters  92  project from a base which is e.g. cylindrical of the rotary axis  84 , radially of the rotary axis  84  and extending constantly radially of that axis. The cutter  92  may for example comprise two limbs  92   a  extending in an azimuthal direction relative to the rotary axis  84  and merging into cutter curves  92   b  extending transversely thereof, the cutter curves  92   b  then being joined by a transverse cutter  92   c  running approximately perpendicular to the azimuthal direction  96  and thus approximately parallel with the rotary axis  84  (FIG. 3).  
         [0051]    The cutter  92  may for example have two transverse cutters  92   c , from which the curves  92   b  extend in opposite directions and then merge into the limbs  92   a , which link the curves  92   b  located at each side of the transverse cutters  92   c  as shown on a larger scale in FIG. 3.  
         [0052]    The cutting action of the cutter  92  takes place as shown in FIG. 3, through the combined action of an effective section of cutter  92   s  located the most minimal distance opposite or almost touching a corresponding section of anvil surface  76   s ; rotation of the rotating cutting tool  80  and co-rotation of the anvil roller  70  cause successive sections of cutter  92   s  and anvil surface  76   s  to be in their effective position and cooperate in cutting.  
         [0053]    In order to define a short distance between the cooperating cutter sections  92   s  and anvil surface sections  76   s  or so-called slight contact between them, the rotating cutting tool  80  is provided with two supporting rings  100  and  102  which are non-rotatably connected; the rings may for example be arranged on both sides of the cutter  92  coaxially with the rotary axis  84  and may have respective surfaces  104  and  106  arranged e.g. cylindrically of the axis  84  and lying on supporting surfaces  108  and  110  of the anvil roller  70 , the supporting surfaces  108  and  110  possibly being formed e.g. by parts of the anvil surface  76 .  
         [0054]    Support is provided by supporting ring sections  104   s  and  106   s  seated on corresponding sections  108   s  and  100   s  of supporting surfaces  108  and  110 ; when the rotating tool  80  is turned successive supporting ring sections  104   s  and  106   s  in the direction counter to the rotary direction of the tool cooperate with successive supporting surface sections  108   s  and  110   s  in the direction counter to the rotary direction of the anvil roller  70 .  
         [0055]    The cooperating supporting ring sections  104   s ,  106   s  and supporting surface sections  108   s  and  100   s  take up a total load pressure A with which the rotating curring tool  80  bears on the anvil roller  70  and which is a part of the biasing force V comprised in that force.  
         [0056]    However the biasing force V leads not only to the formation of load pressure A acting on the anvil roller  70  via supporting rings  100  and  102  but also to a cutting force S, which is connected to an effective cutting length in the particular cutter section  92   s.    
         [0057]    As shown in FIG. 4 taking the supporting ring  102  as an example, each supporting ring  100 ,  102  is seated on an expansion member  120  which engages round the respective tool shaft  82 ,  86  in the form of an expansion member ring and which has a load pressure surface  122  associated with and seated on a peripheral surface  124  of the respective tool shaft  82 ,  84 , the expansion member being supported thereby radially of the rotary axis  84 .  
         [0058]    The expansion member  120  further has an annular surface  126  facing towards the cutting tool  80  and lying against an end face  130  of a cylindrical base member  132  of the cutting tool  80 , the member  120  is preferably fixed against the end face  130  by tensioning elements  134  e.g. in the form of screws and is thus fixed non-positively to the end face  130  by the annular surface  126 .  
         [0059]    Relative to the rotary axis  84  the expansion member preferably has a radius smaller than a radius of the base member  132  of the cutting tool  80 .  
         [0060]    The expansion member  120  further has an outer conical surface  140  extending at a small conus angle to the rotary axis  84 ; the conus angle of the outer conical surface  140  may for example have a conus ratio of 1:10.  
         [0061]    The shape of the conical surface  140  is such that it starts from an external annular surface  136  of the expansion member  120  facing away from the base member  132  and widens out towards the annular surface  126  facing towards the base member  132 , that is to say, an outer radius of the external annular surface  136  is smaller than an outer radius of the internal annular surface  126 , provided that both annular surfaces  126 ,  136  extend from the load pressure surface  122  extending cylindrically of the rotary axis  84 , in a radial direction and perpendicular to the axis  84  as far as the external tapering surface  140 .  
         [0062]    The respective supporting ring, ring  102  in FIGS. 4 and 5, itself has an internal conical surface  150  at a side opposite the supporting ring surface  106 ; the surface  150  runs conically to an axis of the supporting ring  102 , which coincides with the rotary axis  84  in the state mounted on the cutting tool  80 , and has the same conus ratio as the external conical surface  140 .  
         [0063]    The internal conical surface  150  similarly extends over the whole width of supporting ring  102 , i.e. from an external annular surface  152  thereof to an annular surface  154  of the ring  102  at least partially facing towards the end face  130  of the base member  132  of the cutting tool  80 .  
         [0064]    The radius of the internal conical surface in a plane defined by the external annular surface  152  and extending perpendicular to the rotary axis  84  is smaller than the radius of the internal conical surface  150  in a plane defined by the annular surface  154  and extending perpendicular to the axis  84 .  
         [0065]    Clamping elements  156  are likewise provided to fix the respective supporting ring  100 ,  102 , e.g. ring  102  in FIGS. 4 and 5; these elements may e.g. be screws which each pass through an opening  158  in the supporting ring  102  and have their threaded sections  160  screwed into tapped holes in the base member  132 , the holes starting from the end face  130  perpendicular to the rotary axis  84  and extending into the base member  132  preferably parallel with the axis  84 .  
         [0066]    The clamping elements  156  may be clamped on strongly enough to enable the particular supporting ring, i.e. ring  102  in this case, to have an internal part  164  of the annular surface  154  applied to the end face  130  and thus supported against that face.  
         [0067]    The internal conical surface  150  of the respective supporting ring, in this case ring  102 , is dimensioned so that, when the ring  102  is placed on the expansion member  120  and moved parallel with the rotary axis  84  towards the end face  130 , the material of the ring  102  is stretched in a radial direction and the whole ring is thus expanded radially of the rotary axis  84 ; the radial stretching of the supporting ring  102  is below the elastic expansion limit, which is dependent on the ring material, and is e.g. less than 0.1% of the ring diameter.  
         [0068]    Maximum stretching of the supporting ring  102  is e.g. at a value of less than 80% of the elastic expansion limit, and is used when the cutter  92  is new and unworn. When a web of material  90  is cut for a certain period with an initially new cutter  92  in the cutting tool  80 , the cutter  92  becomes worn and the distance to which it extends radially from the rotary axis  84  is thus reduced by some hundredths of a millimeter; this reduction is however enough to make the cutting action of the cutter  92  inadequate for sensitive webs of material  90 .  
         [0069]    In that case, in the cutting machine according to the invention, the radial stretching of the supporting ring  102  may be reduced by moving the ring  102  slightly away from the end face  130  of the base member  132  of the cutting tool  80 , and thus sliding the internal tapering surface  150  over the external tapering surface  140  parallel with the rotary axis  84 , thereby reducing the stretching of the ring  102  by some hundredths of a millimeter.  
         [0070]    For this purpose the clamping elements  156  are first released. As a simple way of moving the supporting ring  102  away from the end face  130  however, pressure elements  166 , e.g. in the form of screws, are inserted in the clamping elements; the screws engage in tappings  168  in the supporting ring  102  and, when tightened, act against an indentation  170  in the end face  130  which acts as a thrust bearing for the screws, thus enabling the part  164  of the annular surface  154  of the ring  102  to be positioned a distance A away from the end face  130  as shown in FIG. 6; as the ring  102  has been stretched only within a range below the elastic expansion limit, as already described, when the annular surface part  164  of the ring  102  is moved away from the end face  130 , the ring  102  contracts radially of the rotary axis  84  as permitted by the wedge angle of the conical surfaces  140  and  150 , and the diameter of the supporting ring surface  106  is reduced.  
         [0071]    In order to pre-define the reduction in the diameter of the supporting ring  102 , distance elements  180  of a thickness A′, e.g. in the form of pieces of foil or possibly an encircling foil ring, are inserted between the part  164  of the annular surface  154  of the ring  102  and the end face  130  as shown in FIG. 7; then the ring  102  is again clamped to the base member  132  so that the annular surface part  164  is braced against the distance element  80 , which is in turn clamped against the end face  130  again, and thus by means of the distance element  180  the supporting ring  102  is stabilized again by the end face  130  and the annular surface part  164 , which is supported against the end face by the distance element  180 ; even when the diameter of supporting ring area  106  is reduced, the stability of the ring  102  is consequently the same as at maximum stretching of the ring  102  with annular surface part  164  directly in contact with the end face  130 .  
         [0072]    According to the thickness A′ of distance elements  180 , successive insertion of a plurality of these elements enables the diameter of the surface  106  of the supporting ring  102  to be reduced and adapted to the wear on the cutter  92 .  
         [0073]    In accordance with the invention the internal conical surface  150  is always dimensioned relative to the external conical surface  140  in such a way that, even when a minimum diameter of the supporting ring surface  106  is envisaged, the supporting ring  102  itself is stretched radially of the rotary axis  84  by the internal conical surface  150  and the external conical surface  140 ; consequently the internal conical surface  150  is always seated on the external conical surface  140  with tension, in order to avoid any radial flexibility of the supporting ring  102  owing to its support by the expansion member  120 .