US3540335A

US3540335A - Ultramicrotome with means for adjusting the level of the liquid in the collecting vessel of the microtome

Info

Publication number: US3540335A
Authority: US
Inventors: Hellmuth Sitte
Original assignee: C Reichert Optische Werke AG
Current assignee: C Reichert Optische Werke AG
Priority date: 1967-07-27
Filing date: 1968-07-25
Publication date: 1970-11-17
Anticipated expiration: 1987-11-17
Also published as: AT267217B; DE1993223U

Description

United States Patent Inventor Appl. No.

Filed Patented Assignee Priority ULTRAMICROTOME WITH MEANS FOR ADJUSTING THE LEVEL OF THE LIQUID IN THE COLLECTING VESSEL OF THE MICROTOME 13 Claims, 7 Drawing Figs.

U.S. Cl. 83/167, 8 3/9 1 5.5

[51] Int. Cl G0ln 1/06 [50] Field ofSearch 83/167, 170,171, 651, 915.5

References Cited UNITED STATES PATENTS 3,225,639 12/1965 Martinelli Primary Examinerwilliam S. Lawson Attorney-Michael S. Striker Patented Nov. 17, 1970 3,540,335

Sheet 1 of4 I INVENTOR 5 HEM/11477! 8 27 E ATTORNEY Patehted Nov. 11, 1970 3,540,335

Sheet 2 3 (Prior/4r! INVENTOR H :44 n u m 5 1 rr;

ATTORNEY Patented Nov. 17,- 1970 3,5405335 Sheet 3 of4 mvsmoa H unum 6/77:

BY 071.?100/ 16m!!!- ATTORNEY BACKGROUND OF THE INVENTION The present invention relates to ultramicrotomes, and more specifically to means for adjusting the level of the liquid in a collecting vessel fixed to the cutting knife of the microtome to one side of the cutting edge thereof.

As known in the art, cutting knives of ultramicrotomes are provided with small collecting vessels fixed to the cutting knife of the microtome to one side of the cutting edge of the knife, and such a collecting vessel is filled with liquid having a level flush with the upper edge of the cutting knife so that thin tissue sections cut by the knife may be collected on the upper surface of the liquid in the collecting vessel. The level of the liquid in the collecting vessel has to be adjusted, tor reasons which will be explained later on in detail, in a very exact manner so that the liquid vessel is in one plane with the upper edge of the cutting knife. Since the volume of such a collecting vessel is necessarily very small, in the order of l emf, the exact adjustment of the liquid level in the collecting vessel is connected with considerable difficulties.

It is one object of the present invention to provide means, which can be operated in an efficient manner and without requiring any special skills, for changing the amount of liquid in the collecting vessel.

It is a further object of the present invention to provide such means for adjusting the level of the liquid in the collecting vessel of a microtome which are releasably connected to the cutting knife of the microtome and which can be operated from a place spaced from the cutting knife.

It is a further object of the present invention to provide for adjusting means for adjusting the level of the liquid in the collecting vessel of a microtome which are constructed of relatively few and simple parts so as to be produceable at reasonable cost and so as to stand up properly under extended use.

SUMMARY OF THE INVENTION With these objects in view, the present invention comprises, in combination with an ultramicrotome having a cutting knife with an upper cutting edge and a collecting vessel fixed to the cutting knife to one side of the cutting edge and adapted to be filled with liquid up to the cutting edge ofthe knife for collecting sections cut by the ultramicrotome, means for changing the amount of liquid in the collecting vessel and for adjusting the level of the liquid in the vessel and including a tubular member extending from above into the vessel and having a lower open end for the passage of liquid into and out from the collecting vessel and being located at an elevation below that of the cutting edge of the knife so as to extend into the liquid in the vessel when the latter is filled with liquid up to the cutting edge of the knife.

Support means, preferably, support the tubular member adjustable in at least two directions relative to the cutting edge.

Preferably, the support means for adjustably supporting the tubular member are mounted on mounting means which adjustably mount the cutting knife on a support so that the support means and the tubular member mounted thereon will follow any adjustment of the position of the cutting knife.

It is further preferred to connect the support means supporting the tubular member releasably to the mounting means.

which carry the cutting knife so that before any necessary exchange 'of the cutting knife the support means may be removed from the mounting means of the cutting knife so as not to hamper any necessary exchange of the cutting knife.

The other end of the tubular member is preferably connected by a flexible tubing to the outlet end of a resiliently compressible liquid container with which means cooperate for gradually compressing the container so as to transfer liquid from the latter through the flexible tubing and the tubular member into the collecting vessel.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawing.

BRIEFDESCRIPTION OF THE DRAWING FIGS. 1 and 2 are partially sectioned side views respectively schematically illustrating the cutting knife of an ultramicrotome, the collecting vessel fixed to the cutting knife, and other elements of the ultramicrotome cooperating with the aforementioned elements;

FIG. 3 is a side view schematically illustrating an arrangement according to the prior art for adjusting the liquid level in the collecting vessel of the microtome;

FIG. 4 is a schematic, partially sectioned, perspective view of an arrangement according to the present invention for adjusting the liquid level of the collecting vessel of a microtome;

FIG. 5 is a partially sectioned schematic side view and illustrating part of the arrangement shown in FIG. 4;

FIG. 6 is a sectioned side view illustrating part of another embodiment according to the present invention; and

FIG. 7 is a partially sectioned front view of a portion of the arrangement shown in FIG. 5.

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 1 and 2 schematic-ally illustrate the general arrangement of a microtome provided with a collecting vessel on the cutting knife of the microtome. As shown in FIG. I the microtome may include a cutting knife I of substantially triangular cross section which may be formed from glass, and a collecting vessel the wall of which is formed by a thin strip of plastic material 2 connected at the bottom edge thereof to the cutting knife I in a sealed manner by a small mass of wax 3 or the like. The thus formed collecting vessel is arranged to one side of the upper cutting edge of the cutting knife 1 and the collecting vessel is filled with a suitable liquid, for instance distilled water, so that the level of the liquid in the collecting vessel is in one horizontal plane with the upper cutting edge of the knife. Inthis way, thin tissue sections 6 cut from the block 4 during reciprocation of the latter along a path 5 may float away on the upper surface ofthe liquid in the collecting vessel from the upper cutting edge of the knife so that the sections 6 may be picked up by carrier strips or nets from the upper surface of the liquid in the collecting vessel.

An exact adjustment of the level of the liquid in the collect- 'ing vessel is for various reasons very important. If the upper surface of the liquid in the collecting vessel is convex, as shown at 7 in FIG. 2, then microvibrations will be created in the sections 6 cutoff from the block 4, and such microvibration will hinder an electrone optical examination of the sections. On the other hand, a concave upper liquid surface. as indicated at 8 in FIG. 2, will quickly cause withdrawal of liquid from the upper edge of the cutting knife I so that the sections will not properly slide any longer on the dry cutting edge but will be pushed together and not be usable any longer. A further reason for exactly adjusting the upper surface of the liquid in the collecting vessel is that the thickness of the cuttissue sections has to be estimated according to interference colors. For this purpose it is known to provide on ultramicrotomes a source of light, preferably in the form of a fluorescent tube 9, as shown in FIG. 1, arranged in such a manner that the light emanating therefrom will be reflected by the planar horizontal upper liquid surface in the collecting vessel directly into the objective pair 10 of a stereomicroscope indicated in FIG. I. The interference phenomena which permit on the basis of brightness and color differences an estimation of the thickness of the cuts can be observed only from the objective pair 10.

The adjustment of the upper level of the liquid in the collecting vessel has up to now been done mainly by dropwise adding or sucking off water from the collecting vessel by means of a burette or by means of a syringe, which method has however various disadvantages, Persons who are not very dexterous will encounter considerable difficulties to exactly adjust the small volume of liquid in the collecting vessel, which is usually in the order of about 1 cm.", in such a manner that the upper surface of the liquid will be located in one horizontal plane with the upper edge of the cutting knife. Since during use of the ultramicrotome the position of the liquid level in the collecting vessel continuously changes due to removal of liquid from the collecting vessel during fishing of the cut sections 6 therefrom, as well as due to e\ aporation of the liquid, small leaks in the collecting vessel and other circumstances, it is necessary to continuously adjust the liquid level in the collecting vessel. Even a person highly skilled in this manipulation will spend a considerable time for adjusting the liquid level. Manipulation in the region of the cutting edge of the cutting knife 1 will, in addition, produce a thermal effect on the instrument which will detrimentally affect the further cutting operation. Furthermore, the upper surface of the liquid is in most cases due to small irregularities in the wall of the collecting vessel and on the cutting edge of the knife not perfectly plane so that only a limited area of the upper surface will satisfy the above-mentioned, reflection requirements. In other areas it is hardly possible to recognize the cut sections and in no case it is possible to judge the thickness and quality thereof. In this case it is necessary in order to properly observe the cut section to move the latter on the upper surface or to adjust the position of the upper surface of the liquid in the collecting vessel. Both manipulations may lead to a loss of some of the cut sections.

A perfect arrangement for adjusting the level of the liquid in a collecting vessel of the aforementioned kind has therefore to satisfy the following conditions:

The arrangement has to be'independent from the skill of the operator, i.e., it has to be operable in an extremely simple manner. The arrangement has also to permit adjustment of the liquid level without manipulation in the region of the cutting edge of the knife, that is by remote control. In addition the arrangement has to assure an exact dosing of the liquid addition or an exact dosing of removal of liquid so that the upper level of the liquid may be located in one horizontal plane including the upper edge of the knife so as to provide a perfect reflection of the image of the cut sections into the objective pair 10.

For this purpose an arrangement as schematically illustrated in FIG. 3 has already been suggested in which a collecting vessel formed by a sheet metal member 11 cemented to the glass cutting knife 1 was provided and in which a small tube 12 extended through an opening in the sheet metal member 11 and was carried thereby. It was also suggested to fasten such a tube connection to the metal frame of diamond cutting knives. The tube 12 has been connected by a hose 13 to means for supplying liquid to the tube, for instance a syringe 14 the piston 15 of which was movable in axial direction by a screw arrangement 16, 17 connected thereto and turnable by a knob 18 at the outer end of the screw so as to move the piston 15 in axial direction. While the arrangement shown in FIG. 3 theoretically satisfies the above-mentioned conditions, this arrangement did not work out satisfactorily in practice, since cementing of the sheet metal member 11 carrying the tube 12 onto the cutting knife has been considerably more difficult than the forming of a collecting vessel by a plastic strip and since the mounting of such an arrangement on the frame of a diamond knife was connected with the risk of damaging the cutting edge of the diamond knife.

The arrangement according to the present invention differs basically from the known arrangement shown in FIG. 3. In the arrangement according to the present invention the collecting vessel is formed from a plastic strip in the same manner as shown in FIGS. 1 and 2, but the tube for feeding liquid in and out of the collecting vessel is not carried by the wall of the collecting vessel, but the tube extends from above into the collecting vessel so that the lower open end of the tube is below the normal level of the liquid in the collecting vessel. Accord ing to the present invention the tube is supported by support means independent from the wall of the collecting vessel and the tube support means are preferably connected to the mounting means which carry the cutting knife so as to be adjustable together with the latter. However, the support means which support the tube are constructed in such a manner so as to permit adjustment of the position of the tube with respect to the cutting knife.

The arrangement according to the present invention is shown in a nonlimiting manner in FIGS. 4-7.

Referring now to these FIGS., and especially to FIGS. 4 and 5, it will be seen that the arrangement according to the present invention includes a cutting knife I of substantially triangular cross section having an upper cutting edge which is mounted on mounting means 19 ofa cross section as best shown in FIG. 5, movable on the mounting means in substantially horizontal direction in a known manner, not forming part of the present invention, by the knob 19a shown in FIG. 4, and the mounting means 19 are in turn mounted in a slot of a support or block 20 angularly adjustable about a horizontal axis in a known manner by means of the knob 20a so that the angle e (FIG. 5), which the front face of the cutting knife 1 includes with the path 5 along which the block 4 is reciprocated, may be adjusted.

The small tubular member 21 which serves to feed liquid in and out of the collecting vessel formed by the plastic strip 2, sealingly connected at the bottom edge thereof to the rear face of the cutting knife 1, extends with a bent portion thereof over the upper edge of the plastic strip 2 into the interior of the collecting vessel so that the lower open end of the tubular member 21 is below the normal level of the liquid in the col lecting vessel. The tubular member 21 is carried by support means so that the position thereof with regard to the collecting vessel may be adjusted in substantially vertical and substantially horizontal direction or by turning the support means about its axis as indicated by the arrows in FIG. 5. The support means supporting the tubular member 21 preferably comprise a substantially upright hollow cylindrical member 23 formed in the wall thereof with a pair of opposite longitudinally extending slots 23a and a solid tubular member 22 in the hollow tubular member 23 and frictionally engaging the inner surface thereof so as to be shiftable in axial direction and to be held by friction in any shifted position. The member 22 is formed with a bore transverse to its axis through which the tubular member 21 extends to be shiftable in axial direction while being frictionally held in any adjusted position. The member 22 may for instance be formed from rubber so as to be slightly compressible. The support means 22, 23 supporting the tubular member 21 are preferably mounted on the mounting means 19 for the cutting knife and removably therefrom in a simple manner. For this purpose a pair of cooperating means respectively fixed to the lower end of the member 23 and to the mounting means 19 may be provided for releasably attaching the support means, that is the member 23 thereof, to the mounting means 19.

The pair of cooperating means may be constituted, for instance, by a permanent magnet 25 mounted in the lower end portion of the member 23 and engaging with the flat bottom face thereofa magnetizable portion of the mounting means 19 as shown in FIG. 6.

On the other hand, the pair of cooperating means may comprise a female socket member 24a projecting upwardly from the mounting means 19 as shown in FIG. 5, and a male socket member 24 fixed to the lower end of the member 23 and projecting downwardly therefrom into the cavity of the female socket member 2411, as shown in FIGS. 5 and 7. The male member 24 has preferably a cylindrical outer surface so as to be turnable in the socket member 24a.

The tubular member 21 is connected by a hose or flexible tubing 13 to a liquid supply means which may comprise a rubber ball 26 having an outlet end to which the hose 13 is connected, and the rubber ball 26 is loosely mounted in the cavity of a cylindrical member 30 which above the cavity in which the rubber ball 26 is located is provided with an axial bore formed with an inner screw thread with which the outer screw thread of a spindle 29 extending through the axial bore of the member 30 is threadingly engaged. The spindle 29 is likewise formed with an axial bore in which a cylindrical rod 28 is slidably arranged extending with its upper end beyond the upper end of the spindle 29. The rod 28 serves for quickly filling the interior of the rubber ball 26 with liquid by detaching the support means 22, 23 from the mounting means of the cutting knife and by dipping the open end of the tubular member 21 in a liquid container after first pressing the rod 28 downwardly into the spindle and thereby compressing the rubber ball 26. After release of the rod 28, the rubber ball 26 will resiliently expand so that water will be sucked into the interior of the rubber ball. Subsequently thereto, the support means 22, 23 are again mounted on the mounting means 19 of the cutting knife 1 and liquid from the rubber ball 26 may be transferred into the collecting vessel formed by the plastic strip 2 by turning the spindle 29 by means of its upper serrated portion 27 so that liquid is transferred from the interior of the rubberball 26 through the hose l3 and the tubular member 21 into the collecting vessel. By turning the spindle subsequently thereto in one or the other direction, the upper level of the liquid in the collecting vessel may be very exactly adjusted. The position of the end portion of the tube 21 can be adjusted so that the end portion in the collecting vessel will be below the level of the liquid therein and so that the end portion will be out of the way of the cut sections 6 floating on the liquid in the collecting vessel. Any necessary adjustment can be made in a simple manner by shifting the tube in the bore of the member 22 or by shifting the member 22 in axial direction within the hollow cylindrical member 23. Whenever an exchange of the cutting knife 1 is required, the support means 22, 23 for the tubular member 21 may easily be removed from the mounting means of the cutting knife to facilitate exchange of the latter.

The arrangement according to the present invention, especially the arrangement of the tubular member 21 and the support means therefore may be used in connection with cutting knives of any type and material and with collecting vessels connected thereto formed by a plastic strip or any other desired material.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of ultramicrotomes differing from the types described above.

While the invention has been illustrated and described as embodied in an ultramicrotome with means for adjusting the level of the liquid in the collecting vessel of the microtome, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range ofequivalence of the following claims.

lclaim:

1. In combination with an ultramicrotome having a cutting knife with an upper cutting edge and a collecting vessel fixed to the cutting knife to one side of the cutting edge and adapted to befilled with liquid up to the cutting edge of the knife for collecting sections cut by the ultramicrotome, means for changing the amount of liquid in the collecting vessel and for adjusting the level of the liquid in said vessel and comprising a tubular member extending from above into said vessel and having a lower open end located at an elevation below that of the cutting edge of the knife, a remote liquid container of changeable volume, and tubing connecting said remote container with the other end of said tubular member.

2. The combination as defined in claim 1, and including support means for supporting said tubular member adjustable in at least two directions relative to said cutting edge.

3. The combination as defined in claim 2, and including mounting means for mounting said cutting knife on a support, said support means for said tubular member being mounted on said mounting means.

4. The combination as defined in claim 3, wherein said mounting means are adjustably mounted on said support.

5. The combination as defined in claim 3, wherein said support means being releasably connected to said mounting means.

6.-The combination as defined in claim 3, wherein said support means have a lower end and means on said lower end of said support means for releasably connecting said support means to said mounting means.

7. The combination as defined in claim 3, and including a pair of cooperating means respectively fixed to said support means and said mounting means for releasably attaching said support means to said mounting means.

8. The combination as defined in claim 7, wherein said pair of cooperating means comprise a female socket member and a male member releasably inserted in said female socket member.

9. The combination as defined in claim 8, wherein said female socket member is fixed to said mounting means and said male member is fixed to a lower end of said support means and frictionally held in said socket member.

10. The combination as defined in claim 9, wherein said male member is turnably held in said socket member.

11. The combination as defined in claim 7, wherein said pair of cooperating means comprise a permanent magnet and a portion of magnetizable material cooperating with said magnet for releasably attaching said support means to said mounting means.

' 12. The combination as defined in claim 2, wherein said support means comprises a hollow substantially upright cylindrical member formed in opposite wall portions thereof with a pair of elongated slots extending substantially in the direction of the axis of said hollow cylindrical member, a solid cylindrical member in said hollow cylindrical member and frictionally engaging the inner surface thereof so as to be adjustable in axial direction, said solid cylindrical member being formed with a bore therethrough extending transverse to the axis thereof, said tubular member extending through said bore adjustable in longitudinal direction and turnable about the axis of the latter.

13. The combination as defined in claim 2, wherein said remote liquid container is resiliently compressible and including means cooperating with said compressible liquid container for gradually compressing the same so as to transfer liquid from said container into said collecting vessel.