FR2529678A1 - MICROTOME COMPRISING MEANS FOR VERIFYING THE STATE OF THE KNIFE - Google Patents

Abstract

THE KNIFE 3 IS CARRIED BY A KNIFE HOLDER 12 WHICH CAN PIVOT AROUND AN AXIS EXTENDING ALONG THE CUT EDGE 3 OF THE KNIFE, BETWEEN A CUTTING POSITION OF THE SPECIMEN AND AN OFFSET POSITION, FOR WHICH THE SURFACE DISPLAY 15 OF CUTTING EDGE 3 OF KNIFE 3 AND OPTICAL PATH 8 OF A LIGHTING SOURCE FROM BELOW DEFINE AN ANGLE OF AT LEAST 20. CHECKING THE STATE OF THE KNIFE WITHOUT CHANGING THE POSITION OF THE MICROSCOPE D 'OBSERVATION OR LIGHTING.

Description

The present invention relates to microtomes and, in particular,

  Ultramicrotomes More particularly, the invention relates to means for verifying the knife

such microtomes.

  The quality of the thin sections that can be produced by means of a microtome depends substantially on the quality of the cutting edge of the knife. In particular, in the case of ultra-microtomes, in which glass knives are normally used, It is important to be able to check that the knife is not damaged (for example it does not show any splinters or serrations) and that it is not soiled, before implementing the

  cutting operations The inspection of the knife is usually

  For this purpose, it is provided in known microtomes that the microscopes and / or the lighting system from below is adjustable, or that the knife is immobilized at an angle.

  more oblique in the knife holder for examination.

  It is also known to install on the ultramicrotome a complementary directional light source to check the quality of the cutting edge, this light source illuminating the cutting edge obliquely, from above. These known methods for verifying the quality of the edge of

  cut are either annoying to implement, or neces-

  additional material because it is necessary to rotate the observation microscope and / or the light source from below in the position which makes it possible to see precisely the cutting edge of the knife, after which they must be brought back into their position

  normal to perform the cutting operation.

  The present invention aims to provide means for verifying the quality of the cutting edge of a knife in a simple manner and without expense

significant additional.

  For this purpose, the invention provides a microtome comprising

  a cutter for cutting thin sections of a specimen, an observation microscope, a beneath light source directed on the cutting edge of the knife, and knife checking means comprising a a knife support which is adapted to pivot about an axis extending along the cutting edge of the knife, between a cutting position of the specimen and an offset position in which the uncovered surface of the cutting edge of the knife and the optical path of the lighting source from underneath

  define an angle of at least 200.

  Preferably, this angle does not exceed 450, however.

  In known ultramicrotomes of the type described above,

  the knife support can be pivotally adjusted, but this possibility is used only for the purpose of setting, at the most advantageous value for the specimen in question, the angle of attack of the cutting edge of the knife. , ie the angle between the exposed surface of the knife and the surface of the specimen exposed to the cutting operation As a general rule, this angle does not exceed 100 and, for this reason, the pivoting ability The knife support is limited to 15 by reference to the point O defined by the arc on which the specimen carrying arm of the ultramicrotome is rotatable. The present invention is based on the discovery that it is possible, by significantly increasing the possible offset range of the knife support, without significant additional expense, to move the unclipped surface of the knife to a position that provides good visibility of its cutting edge, for verification purposes of this edge, and to lock it in this position, which

  eliminates the need for additional movement of the micros-

  viewing cope and / or lighting source from below. To obtain the desired result, the minimum angle on which movement must be possible is 200, but

  is advantageous that the angle is greater.

  An embodiment of the invention is described below with reference to the accompanying drawings in which:

  FIG. 1 is a schematic sectional representation of

-3- than an ultramicrotome, and

  Figures 2 and 3 are detailed representations

  schematic of the knife support respectively in the offset position for checking the cutting edge of the knife and in the cutting position. The ultramicrotome shown in FIG. 1 comprises a specimen carrying arm 1 which can be raised and lowered

  and on which a specimen or preparation 2 is attached.

  During this upward and downward movement, the specimen 2 is guided along the cutting edge of a knife 3 so as to produce thin sections. An observation microscope 4 is provided for observing the cutting operation and for check the state of the knife, the optical axis of the microscope being designated by 5 To illuminate the region of the

  knife and specimen, a source of illumination by

  under 6 is disposed within the ultramicrotome, the light beam from the light source 6 being deflected by a deflector mirror 7 according to an optical path

directed to the top 8.

  The ultramicrotome shown in FIG. 1 is of known design and, for this reason, its structure

will not be described.

  Figures 2 and 3 show, on a larger scale, the means provided to allow the movement of -décalage the knife 3 Below -its cutting edge 3 ', the knife 3 carries a receiving bowl 11 When the ultramicrotome is in operation, the bowl 11 is filled with a liquid which receives the thin sections cut from the specimen by the cutting edge 3 'of the knife A cutting support 12, which grips the knife 3 in known manner, is carried by a rocker 13 which can slide along a cylindrical path 14 on the support of the ultramicrotome The movement of the rocker on the cylindrical slide 14 causes the pivoting of the knife support 12 and the

  knife 3 around the cutting edge 3 'of the knife.

  Thanks to these means, it is possible to fix the angle of the uncovered surface 15 of the knife 3 with respect to the surface of the specimen 2 subjected to cutting (this surface is not shown in FIGS. 2 and 3) and also of set the angle X 1 (figure 2) which is necessary for

  observe the cutting edge 3 'of the knife.

  The adjustment is carried out by means of an eccentric cam wheel 16 (shown diagrammatically in FIGS. 2 and 3), the cam of which cooperates with the end face of the balance beam. The eccentricity of the cam is chosen so that, in the offset position of the knife support shown in FIG. 2, the exposed surface 15 and the optical axis 8 define an angle "of at least 200 cm.

  angular position is sufficient to allow observa-

  clear cutting edge 3 'of the knife 3 in order to check the quality of this edge without modifying the optical axis 5 and / or the optical path 8 Although this is not shown in detail in the drawing, it it is obvious that the knife support 12 can be locked by means of known clamping devices both in the offset position shown in FIG. 2 and in the position of

section shown in Figure 3.

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Claims (3)

  1 Microtome comprising a knife adapted to cut thin sections of a specimen, a microscope of observations and a source of illumination from below directed on the cutting edge of the knife, characterized in that it comprises means for checking the state of the knife which comprises a knife support (12) pivotable about an axis extending along the cutting edge (3 ') of the knife (3) between a position adapted to the cutting of the knife specimen (2) and an offset position in which the uncovered surface (15) of the cutting edge (3 ') of the knife (3) and the optical path (8) of the light source below   define an angle of at least 200.   Microtome according to Claim 1, characterized in that   this angle does not exceed 450.   Microtome according to Claim 1, characterized in that the knife support (12) is adapted to slide along a cylindrical path (14) and in that an eccentric device (16) is provided which is adapted to move. the knife carrier (12) between its specimen cutting position and its offset position.