Safety holder for a microtome knife

A knife holder device for a rotary microtome, the device comprising:

• a knife holder having a knife, said knife having a cutting edge;
• a blade guard constructed as a pivotable bow, said blade guard having an outer portion extending substantially parallel to said cutting edge;
• a support element, said support element having a guideway in which said knife holder is mounted such that it can be slid and fixed to deploy different regions of the cutting edge during sectioning operation;
• positioning means, said positioning means being constructed to position said outer portion of said blade guard in any of three positions:
• (i) a protective position directly above and closely spaced apart from said cutting edge of said knife, wherein when said blade guard is in said protective position, said positioning means simultaneously fixes said knife holder in said guideway;
• (ii) a knife-holder-sliding position permitting access to said knife holder with simultaneous release of said knife holder in said guideway, wherein, in said knife-holder-sliding position, said outer portion of said blade guard is lowered relative to said protective position;
• and
• (iii) a knife-changing position permitting free accessibility to said knife holder with simultaneous fixture of said knife holder in said guideway, wherein, in said knife-changing position, said outer portion of said blade guard is lowered relative to said knife-holder-sliding position.