Abstract:
A crank drive system ( 10 ) of a shaft ( 11 ) of a microtome ( 1 ) encompasses a first and a second shaft ( 11, 12 ). The first shaft ( 11 ) is rotatable with a crank ( 13 ) and comprises a first transfer gear ( 14 ). The second shaft ( 12 ) comprises a second transfer gear ( 15 ). A rotation of the first shaft ( 11 ) is transferable from the first transfer gear ( 14 ) to the second transfer gear ( 15 ) to cause the second shaft ( 12 ) to rotate. To make possible, with a microtome ( 1 ), an advance or a lowering of the specimen ( 2 ) in two respective oppositely directed rotation directions with the same crank drive system ( 10 ), the crank drive system ( 10 ) is characterized in that a third transfer gear ( 16 ) is provided. The first transfer gear ( 14 ) is selectably engageable with the second transfer gear ( 15 ) or with the third transfer gear ( 16 ) so that as a result, while the rotation direction of the second shaft ( 12 ) is maintained, the rotation direction of the first shaft ( 11 ) is reversible.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims priority of German patent application 10 2006 031 136.1 filed Jul. 3, 2006, which is incorporated by reference herein. 
     FIELD OF THE INVENTION 
     The present invention relates to a crank drive system of a shaft of a microtome. More particularly, the invention relates to a microtome crank drive system of a type comprising a first and a second shaft or axle. The first shaft is rotatable with a crank and comprises a first transfer means. The second shaft comprises a second transfer means. A rotation of the first shaft is transferable from the first transfer means to the second transfer means of the second shaft. The second shaft can thereby capable of being caused to rotate. The first transfer means is usually joined in permanently nonrotatable fashion to the first shaft. In similar fashion, the second transfer means is joined in permanently nonrotatable fashion to the second shaft. 
     BACKGROUND OF THE INVENTION 
     The aforesaid crank drive system of a shaft of a microtome is used in particular in the context of a sliding microtome of the Applicant, namely in the “Leica SM2000R” model. This sliding microtome is described in printed form in a company brochure of March 2003. In a sliding microtome, the knife that sections the specimen is moved back and forth on a movably arranged slide in order to section the specimen arranged in a specimen holder. The specimen holder is moved vertically onto the knife via a corresponding mechanism, namely a micrometer mechanism; this is also referred to as “advance.” The increment with which the specimen is advanced toward the knife can be set to an accuracy of 0.5 μm via a rotary knob fitted with a scale. Provided on the aforementioned sliding microtome as a further operating element is a crank with which a coarse drive mode for specimen movement toward the knife or away from the knife, i.e. substantially in a vertical direction, can be realized. It is possible as a result, after a sample change, to advance the specimen holder along with the specimen rapidly onto the knife, so that sectioning operations with a definable desired cut thickness can directly follow one another. Provided as a further operating element is a lever (activation lever), guided in an elongated hole and having a knob, with which a manual advance motion of the specimen holder toward the knife can be activated. This knob or lever is usually utilized only in the context of advance in sectioning mode, the advance occurring at the increment currently set using the rotary knob fitted with the scale. This sliding microtome also encompasses an operating state with automatic advance, the operating element relevant thereto being arranged on the microtome slide. This automatic advance is usually utilized upon initial cutting of the sample, and replaces actuation of the activation lever. 
     With regard to the crank drive system for coarse drive, it is at present possible to produce an advance only upon a clockwise rotation. Correspondingly, upon a counterclockwise rotation of the crank drive system, the specimen or specimen holder is moved away from the knife or lowered. It may, however, be desirable to allow an advance of the specimen also to be produced with a counterclockwise rotation, for example because different operators operate a single sliding microtome, and one operator is left-handed and another operator right-handed. Such a requirement at present can be met only by making available two different sliding microtomes, specifically such that with the one sliding microtome an advance is produced by rotating the crank clockwise, and in the case of the other sliding microtome a counterclockwise rotation of the crank produces a respective advance. The rotation direction of the crank drive system is therefore permanently defined in terms of the design. 
     SUMMARY OF THE INVENTION 
     It is therefore the object of the present invention to describe and further develop a crank drive system of a shaft of a microtome, in particular a sliding microtome, with which, in the same microtome, an advance or a lowering of the specimen in coarse drive mode is made possible with two respective opposite rotation directions using the same crank drive system. 
     The crank drive system according to the present invention of the kind cited initially achieves the aforesaid object by way of the features described herein. According thereto, a crank drive system of this kind is characterized in that a third transfer means is provided. The third transfer means could also be joined in permanently nonrotatable fashion to the second shaft. The first transfer means is selectably engageable with the second transfer means or with the third transfer means, so that as a result, while the rotation direction of the second shaft is maintained, the rotation direction of the first shaft is reversible. In other words, a rotation direction reversal of the first shaft is possible by bringing the first transfer means selectably into engagement with the second or the third transfer means, so that as a function of the currently existing engagement situation of the two participating transfer means, the specimen can be advanced with a clockwise rotation of the crank or with a counterclockwise rotation of the crank. 
     What has been recognized according to the present invention is firstly that it is not necessary to provide two microtomes of differing design configuration, specifically in order to provide for a left-hander, for example, a microtome that he or she can operate optimally. Instead an additional mechanism is made available for the coarse drive mechanism that has already been discussed; this additional mechanism makes possible a switchover of the rotation direction of the first shaft while retaining the rotation direction of the second shaft. This additional mechanism encompasses substantially the third transfer means and means that enable the first transfer means to be brought selectably into engagement with the second or the third transfer means. 
     As a result of this action, which in this individual case can be provided relatively simply and inexpensively, in very particularly advantageous fashion a single microtome can be made available that has the desired additional functionality, namely implementing a coarse drive mode for specimen advance in selectably adjustable fashion in both rotation directions. It is thus no longer necessary to procure two microtomes of almost identical design each merely having a different rotation direction, which cannot be switched over, for coarse drive. 
     In a particularly preferred embodiment, the transfer means are embodied in such a way that the first transfer means is positively engageable with the second transfer means or with the third transfer means. With a positive transfer of rotary motion, it can usually be assumed that the rotation performed at the crank by the operator will be transferred from the first shaft to the second shaft without slippage and other transfer losses. A gearwheel pair is fundamentally suitable in each case as a positive transfer means, the first transfer means comprising a type of gear that is embodied in substantially complementary fashion to the gear type of the second or third transfer means. Concretely, the first, second, and/or third transfer means could respectively comprise a gear, a bevel gear, a spur gear, a helical gear wheel, a worm gear or a worm or worm shaft, with the stipulation that the first transfer means is engageable in substantially complementary fashion with the second and the transfer means, and that the first transfer means meshes with the second or third transfer means. 
     In a further embodiment, the transfer means could be embodied in such a way that the first transfer means is nonpositively engageable with the second or third transfer means. Slippage losses in the transfer of rotary motion from the first shaft to the second shaft can occur in this context. This could, however, be advantageous when the specimen is being advanced from below toward the knife and the knife is positioned directly above the specimen, and is moved farther upward without attention by the operator, so that the specimen becomes pressed against the knife and in some circumstances is damaged. In this case a further advance of the specimen could be prevented as a function of the properties to be selected for the nonpositive transfer, specifically if the specimen or specimen holder cannot be moved farther upward because of a resistance. Concretely, the first, second, and/or third transfer means could comprise a wheel having a surface with a high coefficient of friction or one commensurate with the properties just mentioned. 
     It is conceivable in principle for the selectable engagement of the first transfer means with the second or the third transfer means to be implemented comparably with a transmission shifting point. In this case specifically, the second and third transfer means, for example, could be embodied in the form of an idler gear, in other words not be joined in permanently nonrotatable fashion to the second shaft. With a shift bushing joined nonrotatably to the second shaft, which bushing could be arranged between the second and the third transfer means, the second or the third transfer means could be connected nonrotatably to the second shaft as a function of the position of the shift bushing. In this case the first transfer means is constantly in engagement with the second and the third transfer means, and a rotation of the first shaft is always and directly transferred to the second and the third transfer means. Depending on the position of the shift bushing, the rotation of the first shaft is transferred to the second shaft via the second transfer means or via the third transfer means. If the shift bushing is in a neutral position, in which a nonrotatable connection does not exist between the second shaft and either the second or the third transfer means, the two shafts are mechanically decoupled. 
     As an alternative to a switchover system similar to a transmission shifting point, the first shaft could be movable relative to the second shaft, by means of a translating motion, in such a way that the first transfer means is thereby selectably engageable with the second or the third transfer means. In other words the entire shaft, and in some circumstances the crank secured thereon, is thus subjected to the translating motion. Corresponding guidance means arranged on the housing of the microtome are provided for this purpose, so that the translating motion of the shaft is possible in reproducible and purposeful fashion. This translating motion could be substantially a straight-line motion, although any displacement motions (depending on the design-related boundary conditions present in each case) are conceivable. It would also be conceivable in this connection for one shaft to be arranged tiltably or pivotably, in such a way that the first transfer means is thereby selectably engageable with the second or the third transfer means. The tilt or pivot axis would in this case be oriented or arranged around an axis transverse to the longitudinal direction of the tilted or pivoted shaft. 
     In a particularly preferred embodiment, the first shaft is movable relative to the second shaft, by means of a rotary or pivoting motion, in such a way that the first transfer means is thereby selectably engageable with the second or the third transfer means. The entire shaft is rotated or pivoted in this context, specifically about a rotation or pivot axis that is arranged substantially parallel to the longitudinal direction of the rotatably or pivotably arranged shaft, and laterally offset therefrom. 
     In terms of design, a rotary motion of the first shaft could be capable of implementation by way of a rotation of an eccentric sleeve, if the first shaft is rotatably mounted in the eccentric sleeve in an eccentric position. A physical embodiment of this kind is inexpensive and can be achieved economically with relatively simple means. The extent of the eccentric arrangement of the shaft in the eccentric sleeve will depend in general on the physical arrangement of the second and the third transfer means, specifically so that by way of a rotation of the eccentric sleeve, the first transfer means can be brought selectably into engagement with the second or the third transfer means. 
     For manual actuation, the eccentric sleeve could be joined nonrotatably to a shifting plate actuable by an operator. Provision could furthermore be made for the eccentric sleeve to be rotatably mounted directly in a bearing of the microtome housing or in a bushing, the bushing being secured in stationary fashion on the housing of the microtome. The shaft could in this context be combined with the transfer means, eccentric sleeve, and bushing into one modular assembly, thus considerably simplifying fabrication and production of a microtome. 
     The shifting plate and eccentric sleeve could then be embodied in such a way that upon a rotation of the shifting plate through an angle less than or equal to 270 degrees, preferably 180 degrees, the crank drive system is conveyable from a first operating state to a second operating state. In the first operating state the first transfer means is in engagement with the second transfer means, and in the second operating state the first transfer means is in engagement with the third transfer means. In other words, a switchover between the two operating states should be possible by rotation of the shifting plate through a relatively small angle and not through several complete revolutions, specifically so that the switchover can be performed manually by the operator in rapid and simple fashion. 
     End stops that limit the rotation of the shifting plate or of the eccentric sleeve could additionally be provided. For example, the first operating state could be established in the position of the one end stop, and the second operating state established in the position of the second end stop. A snap-locking means, as well as at least two snap-locked positions corresponding to the two operating states, could furthermore be provided, specifically in order to ensure that the shifting plate or eccentric sleeve remains in the position that corresponds to the respective operating state established by the operator. 
     In a very particularly preferred embodiment, an operating state is provided in which the first transfer means is in engagement with neither the second transfer means nor the third transfer means. A snap-locked position could likewise be allocated to this operating state. In this operating state the first shaft is mechanically decoupled from the second shaft so that, in the context of later sectioning and the very small advances (on the order of 1 μm) associated therewith, no blockage or disruption of the advance is caused by frictional losses or resistances of the crank or the first shaft. In this connection, no blockage of an advance motion occurs even if the operator inadvertently immobilizes the crank and thus the first shaft. 
     The first shaft could be joined nonrotatably to a crank. The shaft accordingly rotates, for example, through one-half revolution if the crank is likewise rotated through one-half revolution. Alternatively, a rotary motion of the crank could be transferable to the first shaft or to the first transfer means via an intermediate transmission stage having a definable step-down or step-up ratio. In this case the step-up ratio could be selected in such a way that, for example, the shaft is rotated through two complete revolutions if the crank is manually rotated by the operator through one complete revolution. The selection of the step-up ratio will generally depend on the other physical properties of the micrometer mechanism and on the mechanical drive system coacting therewith. 
     There are various ways of advantageously embodying and refining the teaching of the present invention. The reader is referred, for that purpose, on the one hand to the claims, and on the other hand to the explanation below of the preferred exemplifying embodiments of the invention with reference to the drawings. In conjunction with the explanation of the preferred exemplifying embodiments of the invention with reference to the drawings, an explanation is also given of generally preferred embodiments and refinements of the teaching. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the drawings: 
         FIG. 1  is a perspective view of a sliding microtome known from the existing art; 
         FIG. 2  schematically depicts a perspective view of a crank drive system according to the present invention of a shaft of a microtome; 
         FIG. 3  is a schematic sectioned view of part of the crank drive system according to the present invention; 
         FIG. 4   a  is a schematic plan view of the crank and the shifting plate in a first shift position; 
         FIG. 4   b  is a schematic side view of the crank drive system according to the present invention in a first operating state; 
         FIG. 5   a  is a schematic plan view of the crank and the shifting plate in a second shift position; 
         FIG. 5   b  is a schematic side view of the crank drive system according to the present invention in a second operating state; 
         FIG. 6   a  is a schematic plan view of the crank and the shifting plate in a third shift position; and 
         FIG. 6   b  is a schematic side view of the crank drive system according to the present invention in a third operating state. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Identical or similar components and assemblies are labeled in the Figures with the same reference characters. 
       FIG. 1  shows a sliding microtome  1  of the Applicant, namely the “Leica SM2000 R” model. This sliding microtome is already known from the existing art and does not comprise a crank drive system according to the present invention. In sliding microtome  1 , knife  3  that sections specimen  2  is moved back and forth on a movably arranged slide  4  in order to section specimen  2  arranged in specimen holder  5 . Specimen  2  is usually a histological preparation that is embedded in a paraffin block and is clamped into specimen holder  5 . Specimen holder  5  is moved vertically onto knife  3  via a corresponding mechanism, namely a micrometer mechanism provided in the housing of sliding microtome  1  and not shown in  FIG. 1 . The increment with which specimen  2  is advanced upward toward knife  3  can be set, to an accuracy of 0.5 μm, via a rotary knob  6  fitted with a scale. Provided on sliding microtome  1  shown in  FIG. 1  as a further operating element is a crank  7  with which a coarse drive mode for movement of the specimen toward knife  3  or away from knife  3  (i.e. substantially in a vertical direction) can be implemented. This makes it possible, after a sample change, to advance specimen holder  5  along with specimen  2  rapidly onto knife  3 , so that the sectioning operations at a definable desired cut thickness can directly follow one another. Provided as a further operating element is an activation lever  9 , guided in an elongated hole  8 , with which a manual advancing motion of specimen holder  5  toward knife  3  can be activated. Activation lever  9  is usually utilized only in the context of advance in sectioning mode; the advance occurs with the increment currently set on rotary knob  6  fitted with the scale. This sliding microtome  1  also encompasses an operating state with automatic advance, the operating element relevant thereto being arranged on microtome slide  4 , specifically on the back side (not visible in  FIG. 1 ) of slide  4 . This automatic advance is usually utilized upon initial cutting of the sample, and replaces actuation of activation lever  9 . 
       FIG. 2  is a perspective view of crank drive system  10  according to the present invention that can be used in sliding microtome  1  of  FIG. 1 . Crank drive system  10  comprises a first shaft  11  and, arranged substantially perpendicular thereto, a second shaft  12 . First shaft  11  is rotatable manually by an operator using crank  13 . First shaft  11  comprises a first transfer means  14 , which is embodied in the form of a small bevel gear and which, for the sake of simplicity, will likewise be identified hereinafter by the reference character  14 . Small bevel gear  14  is joined nonrotatably to first shaft  11 . Second shaft  12  comprises a second transfer means  15  that is embodied in the form of a large bevel gear. Large bevel gear  15  is joined nonrotatably to second shaft  12 . The tooth set of large bevel gear  15  faces toward small bevel gear  14 . 
     According to the present invention, a third transfer means  16  is provided which is embodied in the form of a large bevel gear and, in this exemplifying embodiment, is joined nonrotatably to second shaft  12 . Both the second and the third transfer means  15 ,  16  are, for the sake of simplicity, hereinafter respectively identified by reference characters  15  and  16 . The tooth set of large bevel gear  16  likewise faces toward small bevel gear  14 . It is possible to bring small bevel gear  14  into engagement with large bevel gear  16  (i.e. the third transfer means) or with large bevel gear  15  (i.e. the second transfer means). In the first case, small bevel gear  14  accordingly meshes with large bevel gear  16 , so that in this operating state a rotation of shaft  11  is transferred via small bevel gear  14  to large bevel gear  16  of second shaft  12 , and second shaft  12  is thereby also rotated. If crank  13  of  FIG. 2  is therefore rotated counterclockwise (looking at crank  13  from the front), shaft  11  likewise rotates counterclockwise, and large bevel gear  16  and second shaft  12  rotate counterclockwise (looking from above at large bevel gears  15  and  16 ). With this rotation direction of second shaft  12 , specimen holder  5  (not shown in  FIG. 2 ) is moved or advanced vertically upward toward knife  3  of sliding microtome  1 . If small bevel gear  14  is then brought into meshing engagement with large bevel gear  15 , crank  13  of  FIG. 2  can thus be rotated clockwise (once again looking at crank  13  from the front). Shaft  11  likewise rotates clockwise and, in this case as well, large bevel gear  15  and second shaft  12  rotate counterclockwise (once again looking at large bevel gear  15  from above). The spur gear indicated with reference character  17  in  FIG. 2  is of no further significance for crank drive system  10  according to the present invention. Second shaft  12  is rotatably mounted in bearing block  18 . Shaft  12  drives the micrometer mechanism (not shown in the Figure) of the microtome indirectly via spur gear  17 . 
     Transfer means  14 ,  15 , and  16  are embodied in such a way that first transfer means  14  can be brought into positive engagement with second transfer means  15  or with third transfer means  16 . 
     First shaft  11  is movable relative to second shaft  12  by means of a rotary motion, in such a way that the first transfer means, or small bevel gear  14 , can thereby be selectably brought into engagement with the second transfer means (large bevel gear  15 ) or with the third transfer means (large bevel gear  16 ). The manner in which this is implemented in detail in terms of design, in the exemplifying embodiment of the present invention shown in  FIG. 2 , is evident from the schematic sectioned view of  FIG. 3 . 
     First shaft  11  is rotatably mounted in eccentric sleeve  19  and can be rotated relative to eccentric sleeve  19  and independently thereof. The two plain bearings  20 ,  21  are provided for this purpose. Eccentric sleeve  19  is in turn rotatably mounted in a bushing  22  that can be installed in stationary fashion on a housing part  27  of the microtome. First shaft  11  is arranged in an eccentric position in eccentric sleeve  19 , specifically in such a way that rotation axis  23  around which first shaft  11  is rotated exhibits a parallel offset from the central longitudinal axis  24  of eccentric sleeve  19 . Longitudinal axis  24  of eccentric sleeve  19  is drawn in extended fashion, and is located on the lower rim (as drawn in  FIG. 3 ) of shaft  11 , so that longitudinal axis  24  is not visible there. Because of the eccentric arrangement of shaft  11  in eccentric sleeve  19 , upon rotation of eccentric sleeve  19 , shaft  11  is subjected to a rotary motion around longitudinal axis  24  of eccentric sleeve  19 , so that small bevel gear  14  can be brought into engagement with large bevel gear  15  or with large bevel gear  16 , depending on the rotational state of eccentric sleeve  19 .  FIG. 3  further shows that small bevel gear  14  is joined nonrotatably to shaft  11 . 
     Eccentric sleeve  19  is nonrotatably joined to a shifting plate  25  that can be actuated by an operator. Shifting plate  25  and eccentric sleeve  19  are embodied in such a way that upon a rotation of shifting plate  25  through an angle of 180 degrees, crank drive system  10  can be conveyed from a first operating state to a second operating state. In the first operating state, small bevel gear  14  is in engagement with large bevel gear  15 . In the second operating state, small bevel gear  14  is in engagement with large bevel gear  16 . 
       FIGS. 4   a ,  5   a , and  6   a  each show a plan view of crank  13  and of shifting plate  25 . Shifting plate  25  is shown in three different respective positions which correspond to the three operating states provided for crank drive system  10  according to the present invention.  FIGS. 4   b ,  5   b , and  6   b , arranged alongside, respectively show side views of crank drive system  10  according to the present invention in the operating states that correspond respectively to the shift positions of shifting plate  25  that are shown in  FIGS. 4   a ,  5   a , and  6   a.    
     For example, the position of shifting plate  25  in  FIG. 4   a  corresponds to the position shown in  FIG. 2 . Correspondingly, when crank  13  is rotated counterclockwise, shaft  11  and small bevel gear  14  likewise rotate counterclockwise. Small bevel gear  14  is in meshing engagement with large bevel gear  16 . The result of this in turn is that large bevel gear  16  is rotated counterclockwise (looking from above at shaft  12 ). A rotation of second shaft  12  in this rotation direction produces an advance of specimen  2  toward knife  3 . This relationship is also indicated by symbol  26  arranged at the left, toward which grip element  33  of shifting plate  25  points in  FIG. 4   a.    
     The position of shifting plate  25  in  FIG. 5   a  corresponds to the operating state in which first shaft  11  is decoupled from second shaft  12 , and small bevel gear  14  is not in engagement with either large bevel gear  15  or large bevel gear  16 . Even if crank  13  were to be rotated in this operating state, this rotation will not be transferred to shaft  12 . This operating state is shown in the side view in  FIG. 5   b . This relationship is also indicated by symbol  26  arranged at the top center, toward which grip element  33  of shifting plate  25  points in  FIG. 5   a.    
     When shifting plate  25  is in the position according to  FIG. 6   a , small bevel gear  14  is in meshing engagement with large bevel gear  15 . Correspondingly, when crank  13  is rotated clockwise, shaft  11  and small bevel gear  14  likewise rotate clockwise. Large bevel gear  15  and shaft  12  are thus rotated counterclockwise (looking from above at shaft  12 ). A rotation of second shaft  12  in this rotation direction produces an advance of specimen  2  toward knife  3 . This relationship is also indicated by symbol  26  arranged at the right, toward which grip element  33  of shifting plate  25  points in  FIG. 6   a.    
     Shifting plate  25  comprises an annular groove  35  extending over a half-circle, which groove is shown in the sectioned view of  FIG. 3 . Provided on housing part  27  and projecting from the outer surface is a pin (not shown) that engages into groove  35 ; end stops for the rotation range of shifting plate  25  are thereby implemented, namely from the one end position shown in  FIG. 4   a  to the other end position shown in  FIG. 6   a . It is apparent from  FIGS. 4   a ,  5   a , and  6   a  that housing part  27  comprises, on its surface facing toward crank  13 , a depression  28  that, inter alia, visually indicates the rotation range of shifting plate  25  and eccentric sleeve  19 . 
     It is not shown in further detail in the Figures that a ball catch is provided in bushing  22 , which catch snaps into three cutouts  29  (one of which is shown in  FIG. 3 ) each offset 90 degrees. A snap-locking means and three snap-lock positions corresponding to the three operating states are thereby provided, so that shifting plate  25  and eccentric sleeve  19  remain in a position that corresponds to the particular operating state established by the operator. 
     In  FIG. 3 , screw  34  indicates that the cover of crank  13  shown in  FIG. 2  can be secured onto component  30 . Component  30  can be rotated with respect to shaft  11 . Component  31  is joined nonrotatably to shaft  11 . Two cup springs  32  are provided between component  30  and component  31 . Cup springs  32  are preloaded in such a way that component  31  is forced away from component  30  and from small bevel gear  14  (connected via first shaft  11 ). Component  30  is thereby caused to abut against shifting plate  25 , and can be moved very little in an axial direction. Component  31  engages positively, via ball pins  36 , into the cover (not shown in  FIG. 13 ) of crank  13 , so that ultimately crank  13  is joined nonrotatably to shaft  11 . In the event of excessive torque on crank  13 , ball pins  36  (spring-loaded via component  31 ) slip out of the depressions in crank  13  and thus implement a slip clutch. 
     In conclusion, be it noted very particularly that the exemplifying embodiments discussed above serve merely to describe the teaching claimed, but do not limit it to the exemplifying embodiments. 
     Parts List 
     
         
         
           
               1  Sliding microtome or microtome 
               2  Specimen 
               3  Knife 
               4  Slide 
               5  Specimen holder 
               6  Rotary knob 
               7  Crank 
               8  Elongated hole 
               9  Activation lever for activating manual advance 
               10  Crank drive system 
               11  First shaft 
               12  Second shaft 
               13  Crank 
               14  First transfer means of ( 11 ) 
               15  Second transfer means of ( 12 ) 
               16  Third transfer means of ( 12 ) 
               17  Spur gear 
               18  Bearing block of ( 12 ) 
               19  Eccentric sleeve 
               20  Plain bearing in ( 19 ) for ( 11 ) 
               21  Plain bearing in ( 19 ) for ( 11 ) 
               22  Bushing in which ( 19 ) is rotatably mounted 
               23  Rotation axis of ( 11 ) 
               24  Central longitudinal axis of ( 19 ) 
               25  Shifting plate 
               26  Symbols identifying the respective operating state 
               27  Housing part of ( 1 ) in which ( 22 ) is installed 
               28  Depression on ( 27 ), end stop for ( 25 ) 
               29  Cutout on ( 25 ) 
               30  Component on which ( 13 ) can be secured 
               31  Component that is joined nonrotatably to ( 11 ) and engages positively into the cover of crank ( 13 ) 
               32  Cup springs 
               33  Grip element of ( 25 ) 
               34  Screw for fastening cover of ( 13 ) to ( 30 ) 
               35  Groove in ( 25 ) for limiting the rotation range 
               36  Ball pins on ( 31 ) for positive engagement into cover of crank ( 13 )