Abstract:
Cutter head for wood working machines comprising a carrier with at least one receptacle for detachably receiving a cutter unit and a means for adjusting the flight circle of a cutting edge of the cutter unit, wherein in order to facilitate such a cutter head in view of the manufacture and installation thereof and to improve the resharpening ability of the cutter unit, the adjusting means comprises at least one spacer arranged between the cutting edge and the receptacle in an exchangeable manner and defining the distance between the cutting edge and a bearing surface of the receptacle.

Description:
FIELD OF THE INVENTION 
     The invention relates to a cutter head for wood working machines. 
     Such cutter heads are, for instance, used for milling, profiling or planing wood, and, depending on the required cutting performance and the material to be processed, they may be equipped with compact cutters made of the usual cutting steels or with hard metal cutting plates and support plates placed underneath. 
     BACKGROUND OF THE INVENTION 
     A cutter head for wood working machines having a hard metal cutting plate and a support plate placed underneath is known from EP 726 838 B1. In order to guarantee that the cutting edge can rotate again on the same flight circle also after it has been resharpened, the cutting plate can be adjusted. For this purpose the cutting plate comprises a micro toothing on the reverse side thereof engaging into a corresponding micro toothing of the support plate. The micro toothings extend axially relative to the flight circle and have a predetermined distance radially thereto. If the cutting plate needs resharpening, the pressure of the cutting plate acting against the support plate is released and the cutting plate is offset outwardly relative to the support plate by one tooth of the micro toothing. Thus the cutting plate can be resharpened in a manner that the cutting edge is positioned again on the previous flight circle after the resharpening. The possibility of adjustment by micro toothings engaging each other, however, has essential disadvantages. On one hand it is not excluded that the cutting place is inadvertently adjusted by more than one tooth, with the result that more of the expensive hard metal material than would be actually necessary is cut off. Also the mounting of the known cutter unit is difficult, since it has to be secured that the selected engagement points of the micro toothing are maintained also when the cutter unit is inserted and tightened. Moreover, the micro toothings must come up to requested dimensions and must be manufactured with precision, which in view of hard metal cutting plates is possible only with expensive diamond tools. Finally, the cutting plate is in a radial direction only supported on the support plate by the relatively small oblique surfaces of the micro toothing, so that relatively high pressure forces are required. 
     SUMMARY OF THE INVENTION 
     Therefore, the invention is based on the object to provide an easy to manufacture and easy to mount cutter head offering good support of the cutter unit in a radial direction. 
     By the embodiment according to the invention the mode of adjusting the cutter unit is exactly predefined by the previously selected spacer without involving the risk that said predefinition is inadvertently changed during the installation of the cutter unit in the receptacle on the carrier. Moreover, a good support on the carrier is achieved by means of the spacer. Said spacers may be used for cutter units consisting of a compact cutter made of the usual cutting steels as well as for cutter units consisting of a hard metal cutting plate and a support plate. 
     If an adjustment in more than two grades is desired, the spacers should usefully be provided in a set. 
     By the step according to claim  3  with the present invention the radial support is improved. 
     The spacer may be fastened to the cutter unit in advance so that the mounting of the cutter unit is facilitated. 
     Especially advantageous is the use of the embodiment according to the invention in a cutter unit comprising, a cutting plate and a support plate. 
     The invention provides a first preferred possibility to dispose the spacer between the cutting edge and the receptacle. There is also an additional possibility to dispose the spacer between the cutting edge and the receptacle. 
     With this invention the positional security of the spacer relative to the cutter unit is improved. 
     One embodiment of the pressure jaw described in this invention facilitates the mounting additionally. There is also described a particularly preferred embodiment of the pressure jaw facilitating both the mounting of the cutter unit and the adjustment thereof. 
     One embodiment of the pressure jaw generates a pressure force component acting inwardly in radial direction so as to facilitate the mounting and so as to guarantee a firmer seat of the cutter unit in the receptacle. 
     A preferred embodiment for a set of spacers used for the cutter head according to the invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Embodiments of the invention will hereinafter by explained in more detail by means of the drawings, wherein 
     FIG. 1 shows a top view on a cutter head constructed according to the invention in a schematic illustration, 
     FIG. 2 shows the support plate of FIG. 1 in a lateral view, 
     FIG. 3 shows the front view of FIG. 2, 
     FIG. 4 shows the front view of the spacer of FIG. 1, 
     FIG. 5 shows the top view on the spacer of FIG. 1, 
     FIG. 6 shows a lateral view of a set of spacers for the cutter head according to FIG. 1, 
     FIG. 7 shows a front view of a cutting plate usable for the cutter head according to FIG. 1, 
     FIG. 8 shows a front view of a pressure jaw usable for the cutter head according to FIG. 1, 
     FIG. 9 shows the lateral view of the pressure jaw according to FIG. 1, 
     FIG. 10 shows a lateral view of another embodiment of a support plate for a a cutter head according to the invention, 
     FIG. 11 shows the front view of FIG. 10, 
     FIG. 12 shows the front view onto a spacer for the support plate according to FIG. 10, 
     FIG. 13 shows the lateral view onto a spacer set for the support plate according to FIG. 10, and 
     FIG. 14 shows a top view on another embodiment of a cutter head according to the invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 1 shows a cutter head  1  constructed according to the invention, which, in the present embodiment, is designed as a milling cutter for wood working. The cutter head  1  comprises a cylindrical carrier  2 , which, in the wood working machine, is rotatably driven in the direction of arrow A about a rotational axis  3  extending perpendicularly to FIG.  1 . In the present embodiment four receptacles  4  for respectively one cutter unit  5  are distributed at regular intervals over the circumference of the carrier  2 . Each of the receptacles  4  is, as is normal with said cutter heads, designed as a groove extending in axial direction relative to the rotational axis  3  and open in circumferential direction. Flanks  4   a  of each of the receptacles  4  after-running in the rotational direction A are designed as support surfaces for the cutter units  5  with flanks  4   a  of all receptacles  4  having the same alignment relative to the rotational axis  3  and the circumference of the carrier  2  and, if four cutter units  5  are used, being positioned to each other at right angles. The usual micro toothing may be disposed on flanks  4   a , whereby the micro toothing, in the illustrated embodiment, serves the support against centrifugal forces during the operation and as positioning aid during the installation of the cutter unit, and which is shown in FIG. 1 in a dot-dash line. 
     Flanks  4   b  positioned opposite flanks  4   a  of each receptacle  4  are interspersed with an opening  6 , in which a fastening bolt  7  or the like for fastening the cutter unit  5  in the carrier  2  can be accommodated and lowered beneath the surface of the carrier  2 . 
     The base of each receptacle  4  has a bearing surface  4   c , which is preferably slightly raised over the remaining lower periphery of the receptacle  4  and which is exactly aligned to the flank  4   a  in view of its angular position, i.e., in the present embodiment, it forms a right angle with flank  4   a.    
     Each cutter unit  5  comprises in the illustrated embodiment a cutting plate  8  of hard metal having a cutting edge  8   a , a support plate  9  placed behind the cutting plate  8 , a pressure jaw  10  placed between bolt  7  and cutting plate  8  and a spacer  11  acting—as will be explained hereinbelow—as adjusting means, which is detachably connected with the support plate  9  by a catch spring  12 . 
     Each of the cutter units  5  is disposed in the receptacle  4  such that the cutting edges  8   a  of all cutting plates  8  rotate on a common flight circle F with the diameter D about the rotational axis  3 . Diameter D of the flight circle F should preferably be maintained also after the cutting edges  8   a  have been resharpened. 
     The components of each cutting unit  5  will hereinafter be explained by means of FIGS. 2 to  9 . As is shown in FIGS. 2 and 3 the support plate  9  may comprise a toothing  9   a  corresponding to the toothing of flank  4   a  resulting, apart from the pressure force caused by bolt  7 , also in a form-fit engagement between the flank  4   a  of the receptacle  4  and the support plate  9 . On the side opposite the toothing  9   a  the support plate  9  is provided with the support surface  9   b  for the cutting plate  8 . In the area of the support plate  9  facing the base of the receptacle  4  a recess  13  is formed in the support surface  9   b , which extends over the total axial width of the support plate  9  in the direction of the rotational axis  3  and which is open inwardly, i.e. in the direction of the rotational axis  3 . The periphery  9   c  of recess  13  radially facing inwardly extends perpendicularly to the toothed reverse side  9   a  and to the support surface  9   b  so as to extend essentially parallel to the bearing surface  4   c  in the receptacle  4  and being positioned directly opposite thereof during the installation of the cutter unit  5 . Two grooves  14  end in said recess  13  for fastening the catch spring  12 . 
     The recess  13  is designed so as to accommodate the spacers  11  illustrated in FIGS. 4 to  6 . The spacer  11  has a ledge-shaped basic body  15  having an upper side  15   a  and a likewise ledge-shaped shoulder  16  projecting from one of the two wider sides of the basic body  15  and being preferably designed to be integral with the basic body  15 . Basic body  15  and shoulder  16  preferably have the same axial length as the support plate  9 . On the upper side of the shoulder  16  a first bearing surface  16   a  is provided. The underside of the shoulder and basic body are flush and form a second bearing surface  15   b . The upper side  15   a  of the basic body  15  corresponds in view of width and length essentially to the periphery  9   c  of the recess  13  of the support plate  9 , so that the periphery  9   c  is supported on the upper side  15   a , if the spacer  11  is received in the recess  13  and if no toothing is provided between the support plate  9  and flank  4   a . If a toothing is provided, both surfaces  9   c  and  15   a  may have a distance to each other, which should be smaller or equal to half the tooth pitch (about 0.8 mm). In both cases the shoulder  16  projects over the support surface  9   b  so that the cutting plate  8  stands on the bearing surface  16   a  with its inwardly facing bearing surface  8   b . Also the spacer  11  is provided with grooves  17 , which, in a top view, are designed as part of a bore for receiving the catch spring  12 , i.e. they have undercut peripheries. 
     By means of the spacer  11  it is possible to displace the cutting plate  8  relative to the support plate  9  and the rotational axis  3  further radially from the rotational axis  3  in an outward direction once the cutting edge  8   a  has been used up, so that the cutting edge  8   a  of the cutting plate  8  is positioned again with diameter D on the flight circle F after the resharpening, i.e. it has essentially the same distance H to the bearing surface  4   c  as it had prior to the resharpening. In principle this is feasible with only one spacer if a single adjusting possibility is enough, whereby the cutting plate  8  stands with its bearing surface  8   b  on the bearing surface,  4   c  of the receptacle  4  prior to the resharpening and is placed with its resting surface  8   b  onto the bearing surface  16   a  of the single spacer after the sharpening. 
     Preferably, however, a set of spacers  11  in different dimensional grades is provided, as is shown in FIG.  6 . FIG. 6 shows a set of six spacers  11 . 1 ,  11 . 2 ,  11 . 3 ,  11 . 4 ,  11 . 5  and  11 . 6 , whereof each shows an identically dimensioned basic body  15 , however, staggered distances h (h 1 , h 2 , h 3 , h 4 , h 5 , h 6 ) between the bearing surface  15   b  resting on the bearing surface  4   c  in the receptacle  4  and the bearing surface  16   a  on which rests the bearing surface  8   b  of the cutting plate  8 . 
     If the cutting edge  8   a  is now to be resharpened, the user merely has to remove the cutter unit  5  from the receptacle  4 , separate the possibly already used spacer  11  from the support plate  9  by releasing the catch spring  12 , fasten the spacer of the following dimensional grade, for example, spacer  11 . 2 , again on the support plate  9  by means of catch spring  12 , insert the cutting plate  8  and fasten it again in the receptacle  4  by tightening bolts  7 . Afterwards cutting edges  8   a  may be resharpened and the predetermined flight circle diameter D may be cut in again. The spacers  11  are sufficiently large to have them provided with a clearly visible mark so as to facilitate the exchange and to make sure that always the spacer of the directly following dimensional grade is used, so that an inadvertent higher adjustment of the cutting plate can no longer occur. 
     The mounting and the adjustment of the cutting plate  8  is improved by the form-fit connection between the cutting plate  8  and the pressure jaw  10  shown in FIGS. 7 to  9 . As is shown in FIG. 7, the cutting plate  8  has two parallel grooves  18  extending in the rotational direction of the rotational axis  3 , which are disposed at a spot of the cutting plate  8  positioned inside the receptacle  4  and opposite the pressure jaw  10 , even if the cutting plate  8  was resharpened to the last possible dimension. It is not absolutely required that the grooves  18  are produced as dimensionally accurate and precise as the toothing between the support plate  9  and the flank  4   a.    
     As is shown in FIGS. 8 and 9, the pressure jaw  10  has a shoulder  19  on the surface  10   a  facing the cutting plate  8  which is so dimensioned that it can immerse into the grooves  18  while the surface  10   a  presses against the cutting plate  8 . Also the shoulder  19  extends over the entire axial length of the pressure jaw  10 . 
     Opposite surface  10   a  a contact surface  10   b  for the bolt  7  is provided on the pressure jaw  10 , which is even, straight and long enough in radial direction to the flight circle F that the bolt  7  finds a plurality of contact points. The contact surface  10   b  and surface  10   a  are inclined towards each other by an acute angle α, whereby the point having the greatest distance between surfaces  10   a  and  10   b  is arranged radially internally in view of the flight circle F. The angle a is so dimensioned that surface  10   b  extends essentially in the direction of diameter D of the flight circle F about the rotational axis  3  when the pressure jaw  10  is installed. Thus, if the bolt  7  contacts surface  10   b  a component of the fastening force acting radially inwardly is produced, which assists to retain the cutter unit  5  in the receptacle  4  even though the receiving recesses for bolts  7  known from the prior art are not provided. This allows an essentially infinitely variable alteration of the mutual position of bolts  7  and pressure jaw  10 . 
     Due to the engagement of the shoulder  19  of the pressure jaw  10  with one of the two grooves  18  the pressure jaw  10  can thereby, during the installation, be positioned in its position relative to the cutting plate  8  and the support plate  9 , so that the insertion is substantially facilitated. Depending on the spacer  11  used, the groove radially positioned further outside or radially positioned further inside is selected for a form-fit engagement of the shoulder  19 , whereby the contact point of the bolt  7  on the surface  10   b  is infinitely variable. 
     FIGS. 10 to  14  show another embodiment of a support plate  109  comprising an associated spacer  111 . The support plate  109  differs from the support plate  9  by the arrangement and the design of a recess  113 , which, in the present embodiment, is designed as a groove extending over the entire axial length of the support plate  109 . The recess  113  contains a bearing surface, or receiving surface  109   c , facing radially towards the inside and a bearing surface, or receiving surface  109   d , facing radially towards the outside. The support plate  109  may likewise be provided with a back toothing  109   a . If this is not the case, the side of the support plate  109  facing radially towards the inside can be provided with another bearing surface  109   e  underneath recess  113 , with which bearing surface  109   e  the support plate  109  is supported on a bearing surface  4   c  of the receptacle  4 . 
     In said embodiment the support plate  109  is provided with a guiding mechanism for screws  114  for screwing the spacer  111 . In the guiding mechanism for the screw  114  a non-illustrated slider may be received, which is defined in the predetermined position by a screw interspersing the support plate  109  and a screw opening  117  in the spacer  111 . 
     FIGS. 12 and 13 show spacers  111  to be used in the support plate  109 . Each of the spacers  111  is provided with the same ledge-shaped basic body  115  the dimensions of which are so selected that it is accommodated in the recess  113 , whereby each of the outwardly and inwardly facing peripheries  115   a  and  115   b  of the basic body  15  dash against the inwardly and outwardly facing receiving surfaces  109   c  and  109   d  of the support plate  109 . 
     On the side facing the cutting plate  8  the basic body  115  is provided with a ledge-shaped shoulder  116  carrying on its radially outwardly facing side the bearing surface  116   a  for the resting surface  8   b  of the cutting plate  8 . The shoulder  116  projects over the receiving surface  109   d  of the support plate  9 . 
     Analogously to the first embodiment a set of spacers  111  ( 111 . 1 ,  111 . 2 , . . .  111 . 6 ) is provided in different dimensional grades, i.e. with different distances h (h 1 , h 2 , . . . h 6 ) between the bearing surface, or supporting surface  116   a  and lateral edge  115   b.    
     FIG. 14 shows another embodiment of a cutter head  101  in an illustration according to FIG. 1, which, however, comprises the cutter unit according to FIGS. 10 to  13 . The support plate  109  is provided with a back toothing  109   a  engaging into a back toothing  104   a  of a slightly modified receptacle  104 . A pin  120  is provided on the cutter head extending in the base of the receptacle  104  until underneath the radially internally positioned surface  109   e  of the support plate  109 , which has, however, a distance to surface  109   e  being smaller or equal to half the tooth pitch of the toothing  109   a  and  104   a  thereby serving as a mounting aid in embodiments comprising back toothings, which facilitates the insertion of the cutter unit  105  in the predetermined depth. 
     The support plate  109  and the body  102  of the cutter head  101  bear a locating mark  121  visually visible from outside, by which the correct position of the support plate  109  in the receptacle  104  is marked. In this embodiment the cutting plate  8  therefore is supported with its lower edge  8   b  on the bearing surface  116   a  of the spacer  111 , and the spacer  111  is supported on the toothing  104   a  of the receptacle  104  in the carrier  102  via the surfaces of the recess  113  and the back toothing  109   a . It is thereby secured by the marking  121  that the support plate  109  is always in the same radial position in the receptacle  104 , no matter which of the spacers  111 . 1  to  111 . 6  is used. 
     If a support plate  109  without back toothing is used, the support plate  109  may also be supported with its lower surface  100   e  on the pin  120 , whereby the marking  121  is then not required. 
     FIG. 14 further shows a modified pressure jaw  110 , the surface  110   a  of which facing bolt  107  is disposed in a recess  122  being open in the direction of the rotational axis  3  of the carrier  102  and limited radially outwardly by a step  122   a . The recess  122  is so arranged that the surface  110   a  again extends essentially radially. 
     The non-described details correspond to the details of the preceding embodiment. 
     It is, however, also possible to insert the spacer  11  according to FIGS. 4 to  6  in the recess  113  of the support plate  109  according to FIGS. 10 and 11, whereby the support plate  8  is not supported on the bearing surface  4   c  by the detour over the support plate  109 , but solely by the portion of surface  15   b  of the spacer  11  projecting out of recess  113 . 
     In modifications of the described and illustrated embodiments the invention cannot only be used for hard metal cutting plates, but, for instance, also for cutters made of common cutting steel (HS, HSS), whereby, in this case, the bearing surface for the support on the spacer is directly provided on the body of the cutter. The invention can, moreover, not only be used for milling cutters, but, for instance, also for plane knives. Also, the constructive design of the spacers is not restricted to the illustrated embodiments. Thus it is conceivable, for instance, to provide, in the embodiment according to FIG. 10, the support plate with a plurality of parallel groove receptacles into which one and the same spacer may be inserted in a height-adjustable fashion. Furthermore, also the spacer according FIGS. 4 to  6  may be fastened to the support plate or the body of the cutter by screwing. In axial direction both the ledge-shaped shoulder  16 ,  116  on the spacer  11 ,  111  and the grooves  18  in the cutting plate  8  can only be designed as partial supports, e.g. for a two-point contact. Said shape of the grooves may already be molded without problems into the cutting plate during the sinter-metallurgic production thereof, so that a metal removing molding, which is possible only with special tools, is not necessary.