Abstract:
A knife holder ( 5 ) for a microtome for cutting samples ( 4   a ) is disclosed. The knife holder ( 5 ) encompasses several knives ( 2   a,    2   b ) each of which defines a cutting edge ( 16 ). The knife holder ( 5 ) is arranged pivotably about a shaft ( 18 ); and the shaft ( 18 ) is arranged substantially perpendicularly to each cutting edge ( 16 ) of the knives ( 2   a,    2   b ).

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application claims priority of the German patent application 103 46 995.8 filed Oct. 7, 2003 which is incorporated by reference herein.  
       FIELD OF THE INVENTION  
       [0002]     The invention concerns a knife holder. The invention concerns in particular a knife holder for microtome knives for cutting samples. Additionally the invention concerns a microtome with the inventive knife holder.  
       BACKGROUND OF THE INVENTION  
       [0003]     Microtomes and ultramicrotomes are, as a rule, equipped with two knives. One knife serves to trim the sample, and the other knife serves to produce the thin sections. Microtomes and/or ultramicrotomes can also be provided with a cooling chamber. During operation of a microtome with a cooling chamber, two or three knives are usually present in the chamber. One is used for trimming, and the second for producing the ultrathin sections. When a new knife is introduced from outside into the cooling chamber, it is necessary to wait a few minutes for temperature stabilization.  
         [0004]     In the case of the CR-X chamber of RMC, for a knife change the entire chamber must be displaced laterally by means of a drive. This displacement unit is located at the point on the ultramicrotome at which the chamber is attached. If a base-mounted illumination system is built into the chamber as a presetting aid for the alignment operation between knife and specimen, it is also displaced laterally. The illumination geometry must, however, be maintained exactly while observing the presetting operation with the stereomicroscope. The arrangement of the illumination system can therefore only be a compromise between the two knife positions.  
         [0005]     The Leica FCS cooling chamber possesses a capability for displacement of the knife holder in the chamber without modifying the position of the illumination system. In this arrangement, it is possible always to position the knife above the illumination system. This additional displacement capability has, however, the disadvantage that operator errors occur. The knife holder is often displaced along with the illumination system for a knife change, thus disadvantageously modifying the illumination geometry.  
         [0006]     During operation of a microtome or ultramicrotome, it is also necessary at regular intervals to replace, after a certain operating time, the knives that are being used. When a cooling chamber is used, operation of the microtome is interrupted during replacement of the knife, since the temperature equilibrium (or “climate”) inside the cooling chamber is disturbed by the introduction of the new knife. In addition, it is once again necessary to position, i.e. align, the specimen that is to be cut with respect to the new knife, in accurately positioned and exact fashion. This so-called presetting operation also requires time, and care must be taken that neither the knife nor the specimen is damaged in the process.  
       SUMMARY OF THE INVENTION  
       [0007]     It is therefore the object of the present invention to configure a knife holder in such a way that knives can be changed in simple and precise fashion without a long interruption in the cutting process.  
         [0008]     This object is achieved, according to the present invention, by a knife holder for microtome knives for cutting samples, comprising at least two knives are carried by the knife holder, each of which defines a cutting edge, and a shaft being provided by the knife holder about which the knife holder is pivotably arranged, wherein the shaft is arranged substantially perpendicularly to each cutting edge of the at least two knives. It is noted that as used herein, the term “perpendicularly” and alternate forms thereof do not require intersection of two lines or axes, but merely that the lines or axes extend in orthogonal directions relative to one another.  
         [0009]     It is a further object of the present invention to configure a microtome which allows an easy and fast changeover of knives without a long interruption in the cutting process.  
         [0010]     The above object is achieved by a microtome comprising: a cooling chamber, a knife holder surrounded by the cooling chamber, a sample holder arranged opposite to the knife holder, wherein the knife holder carries at least two knives each of which defines a cutting edge, and a shaft is provided around which the knife holder is pivotably arranged for rotation about an axis extending substantially perpendicularly to each cutting edge.  
         [0011]     According to the present invention, a knife holder for a microtome for cutting sample is disclosed, the knife holder carrying several knives each of which defines a cutting edge. The knife holder is arranged pivotably about a shaft, and that shaft is arranged substantially perpendicularly to each cutting edge of the knives. The microtome can also be provided with a cooling chamber. The knife holder is also arranged in the cooling chamber.  
         [0012]     It is particularly advantageous that the knife holder carries two knives that are arranged in such a way that their cutting edges are oriented substantially perpendicularly to one another. In addition, the cooling chamber contains respectively a first and a second stop that coact with the knife holder in order thereby to ensure orientation of the knives.  
         [0013]     The knife holder encompasses a baseplate in which is embodied a recess by which removal of the knife holder from the cooling chamber is enabled, and can be performed without damage to the sample and/or the sample holder. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]     Further advantages and advantageous embodiments of the invention are evident from the dependent claims, and are the subject matter of the Figures below and their descriptions. In the individual Figures:  
         [0015]      FIG. 1  is a side view of an ultramicrotome with cooling chamber, parts of the cooling chamber being omitted in order to elucidate the association between the knife and sample holder;  
         [0016]      FIG. 2  shows a portion of the cooling chamber from above with the arrangement of the rotatable knife holder in a first position;  
         [0017]      FIG. 3  shows a portion of the cooling chamber from above with the arrangement of the rotatable knife holder, the knife holder being pivoted 90 degrees with respect to the first position of  FIG. 2 ;  
         [0018]      FIG. 4  shows a portion of the cooling chamber from above with the arrangement of the rotatable knife holder, the knife holder being pivoted into a removal position; and  
         [0019]      FIG. 5  is a three-dimensional view of the knife holder according to the present invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0020]      FIG. 1  is a side view of a microtome or ultramicrotome  1  having a cooling chamber  10 . Parts of cooling chamber  10  are omitted in order to elucidate the association between at least one knife  2  and sample holder  4 . The at least one knife  2  is inserted into a knife holder  5 . Knife holder  5  is arranged with respect to a base-mounted illumination system  6  in such a way that exit opening  8  of base-mounted illumination system  6  is positioned below knife  2  that is currently in the working position. The working position is defined by the fact that knife  2  is positioned opposite sample holder  4 . In the working position, thin sections of a sample  4   a  that is clamped in sample holder  4  can be produced with the knife.  
         [0021]     Microtome  1  is provided with a stereomicroscope  12  that is mounted at a fixed angle a with respect to perpendicular  13 . This configuration results in optimum contrast during alignment of knife  2  with respect to the surface of sample  4   a  that is to be cut. The provision of base-mounted illumination system  6  means that cutting edge  16  of the particular knife  2  that is in the working position can be better detected and, if necessary, oriented with respect to sample  4   a.    
         [0022]      FIG. 2  shows a portion of cooling chamber  10  from above, with the arrangement of rotatable knife holder  5  in a first position. Knife holder  5  is pivotable or rotatable about a shaft  18 . In the embodiment depicted in  FIGS. 2 through 5 , knife holder  5  carries a first and a second knife  2   a  and  2   b.  Each of knives  2   a  and  2   b  has a cutting edge  16 . Shaft  18  of knife holder  5  is arranged in such a way that it is substantially perpendicularly to cutting edges  16  of knifes  2   a  and  2   b.  Provided between first and second knife  2   a  and  2   b  is a screw  20  with which the position of knife holder  5  after pivoting can be additionally immobilized. Provided respectively in cooling chamber  10  are a first and a second stop  22   a  and  22   b  with which knife holder  5  coacts, and by means of which a respective knife is positioned with respect to sample  4   a  clamped in sample holder  4 . In the depiction of  FIG. 2 , sample holder  4  is pivoted in such a way that first knife  2   a  is positioned opposite sample  4   a.  Knife holder  5  coacts, in this context, with first stop  22   a.    
         [0023]      FIG. 3  shows a portion of cooling chamber  10  from above, with the arrangement of rotatable knife holder  5 , knife holder  5  being rotated 90 degrees with respect to the first position in  FIG. 2 . Second knife  2   b  is here positioned opposite sample  4   a.    
         [0024]      FIG. 4  shows a portion of cooling chamber  10  from above. Rotatable knife-holder  5  is pivoted into a removal position. Knife holder  5  is pivoted 45 degrees so that first and second knife  2   a  and  2   b  are positioned respectively on either side of sample  4   a.  Knife holder  5  can thus easily be lifted upward out of cooling chamber  10 .  
         [0025]      FIG. 5  is a three-dimensional view of knife holder  5  according to the present invention. The two knives  2   a  and  2   b  are arranged at an angle of 90 degrees to one another. Knife holder  5  is rotatable about shaft  18 . With screw  20 , knife holder  5  can be immobilized in a selected position in cooling chamber  10 . Knife holder  5  is furthermore provided with a thread  24  into which a removal aid (not depicted) for knife holder  5  can be threaded. Knife holder  5  comprises a baseplate  26  on which an angle element  28  is embodied. Angle element  28  possesses a first and second limb  28   a  and  28   b.  First knife  2   a  rests against first limb  28   a,  and second knife  2   b  against second limb  28   b.  A first block  30   a  is spaced away from first limb  28   a.  A second block  30   b  is spaced away from second limb  28   b.  First and second block  30   a  and  30   b  are each engaged by a clamping knob  32  adjustably connected to respective limbs  28   a  and  28   b,  whereby first knife  2   a  and second knife  2   b  are respectively pressable against first and second limbs  28   a  and  28   b.  Clamping of first and second knife  2   a  and  2   b  is achieved with knob  32 . Provided on each block  30   a  and  30   b,  in addition to clamping knob  32 , is an angle adjustment knob  34  operatively connected to the associated microtome knife  2   a  or  2   b,  and on which a scale  36  is provided. The relief angle of the two knives  2   a  and  2   b  is respectively adjustable with associated angle adjustment knob  34 . Baseplate  26  moreover possesses a recess  38 . As depicted in  FIG. 4 , knife holder  5  is pivoted into a position such that the entire knife holder  5  can be removed from cooling chamber  10 . In this case recess  38  of baseplate  26  is oriented so that exit opening  8  of base-mounted illumination system  6  is completely visible.