US 2461621 A
Description (OCR text may contain errors)
Feb. 15, 1949. R. R. ALLEN 2,461,621
MIQROTOME BLADE HOLDER Filed April 25, 1947 2 Sheets-Sheet 1 I l/ I l INVENTOR. Poels/PT /P Anf/V l 'Hwa-.JWM l 19 T TOP/Vf? Feb. 15, 1949. Y R] R. ALLEN 2,461,621
MICROTOME BLADE HOLDER Filed April 23, 1947 r 2 sheets-sheet 2 d i2 Z INVENToR.
P05597 P 240V [73:1.5 l T. y I BYQMffV/)M Patented Feb. 15, 1949 MICBQTQME BLADE FOLDER Robert R. Allen, rlington, N. J., assignor t o Cusy tom '.;Scientic- Instruments, yInc., Arlington, 1 N. J., a corporation of New Jersey My present invention relates to improvements in micrctomes',=that is,AV in apparatus fort'cuttin'g specimens to:tldnsslices for microscopic `investi-Uf' l' gation.--.More particularly vit.` relates to micro tome'sfior,` the pre1.`arationV oiispecimens of extreme t-ninness` for1ultramicroscopic examina-- tiernas yfor example, forthe investigation ofr crysv tal lattice `4or atomic -structuresof metals" and' The Vslicing of specimens to the thinness de- Y from the outer endofj the blade; j
sired for -thi's'purpose (insome'cases' as thin' as 0.1 micron or vabout 0.000004A inch) presents exceptional diiiiculties and is 'generally beyond the ability of slicing machines" heretofore available.
In -my present invention I 'provide a microtome carrying a slicing blade which 'moves' at ahigh velocityyasfor example, at a velocity of V-500 to` 600 feet per second,l transversely of the specimen.
lustrated, by way of example, inthe accompany-:: v ying drawings in which- Fig. l is a side view and Fig. 2 an edge viewovf a rotor for moui'it'in'g'y the cutting blades; Fig. S-is a detail view on a somewhat larger scale 05a. page 0f the rotor and cutting blade; Q,"
Fig. *4? fis ka view; of a partv of'therotor Fig. 6 is a lplan view,v and Fligf'l` an of a cutting blade- Fig; 2ll isa viewsimilar to that of Fig, 3A of a part ofr'lthefdi'sc in which'the balancing blank is inountellyA ln the embodiment of the invention shown inV the accompanying drawings, a rotor l 0' for car- Tying `the 'blade may be mounted on a rotatable A slicing blade is rigidly mounted' in radial po'- sition on adisc rotatable Yat ahigh' speed; as for example, on a disc of about three and' one-half inches in diameter to project radially onequarter of an inch beyond the periphery of the disc. It
is balanced by a 'blankso mounted on the disc as to provide an equal and opposite centrifugal When a, rod of the material to be sliced, and of a small' diameter, as for example one-sixteenth of an inch, is movedrslowlylongitudinally and parallel to the axis of the disc against the blade while-the disc is rotated at ahiglrspeed, as for example '70,000 revolutions per minute', slicesof' the specimen arecut to th'edesired thinness and may be caught on a suitable screen for micro-v scopic -investigation.
During rotation'the blade must be supported and held without substantial vibration. The
supporting disc has, therefore, a long hub for mounting ona .coned spindle and tapers radially on a concave taper to a narrow margin in which' the blades are mounted and secured. For this purpose a pair of slots are provided in balanced or diametrically in opposite positions in the edge of the disc, in one of which a knife blade is mounted and secured by a pair of screws and a clamping plate tting into and opening through one face of the disc, and in the other of which a balancing blank is similarly mounted. One radial edge of the knife is sharpened toward the leading face against which the specimen stock is to be fed. This leading face may also slope away from the cutting edge by a slight angle, so as to clear the cut surface of the specimen.
The various features of the invention are il-Y 'spindle ll ofjtapered or Vconed surface on which. it may'be'lsecured by va cap l2 and yscrew I3. The v. rotor li! is widened atits central part to form a 'long hub portion t4 from which it tapersconcavely as at i5 to a relatively 'thin edge margin.
The'surace of the tapering part l 5 is pref'era-v bly concaveinwardlyon a line whichin crossk section is of circular curvature. The curvature lis suchasto 'reducefthe centrifugal force in .thev disc to' aminimum and to Amaintain greater strength where the tension is greatest.
Ondia'metrically'opposite sides of the disc are v provided'slots"for mounting a cutting blade or konsolede e6 adja'blank n. As shown more "particlilarlyin Figs. A3,4 and 5 the blade is inserres radially' late a. no1-, l e' which' extends ln` wardly'a' limited distance from theA peripheral surface of the disc. This slot is somewhatv larger in dimensi'onthanthe blade and preferably one face le of the slot is'on the median plane of the` disc, that isf, it ishalf way between the opposite' iaces'of tneimarginal part. This leaves a `rela-A rtively thinner wall Ztl' on one side and a relatively thicker wall Von the opposite side of the slot. An opening 22, preferably of circular formation, is formed in the thinner wall 20 and is filled with a Vplate 23. A recess 24 is similarly formed in the outer face of the thicker wall 2| and is filled With a plate 25.
The plates 23 and 25 and the wall 2l at the bottom of the opening 2li are provided with a pair The part 28 of the knife I6 that is received in vthe slot I8 has a similar pair of spaced openings The plates 2a kand 25 win, of course, be noshV with the parallel marginal surfaces of the disc. The blade I6 has a part, indicated at 3l, that projects beyond the periphery of the vdisc with a cutting edge 32. This cutting edge is somewhat in advance of the radial line ofthe disc on which the openings 29 and 39 are centered and is preferably advanced slightly beyond the leading edge of the part 28, as indicated at 33 in Fig. 3
i The cutting edge 32 is formed by grindingfthe leading edge on a plane 34 at an angle 35 of 39 or lessandthen on a larger angle 36.- The face 31 of the blade against which thejspeoimen is to be fed isalso cutaway at a slight angle 38 so as to clear the` newly out surface of the speci-men. The blank l1 is received in a slot similar to the slot land on the diametrically opposite part of tn'edisc..V t is securedtherein by a clamping plate, similar to the plateY 23, and screws 39 as shown in Figs. 1 and 3. It is of suiciently greater mass, th an ,the knife IG to compensate for the projection of the knife blade beyond the edge of the discs, and to provide a centrifugal force equal to that ofthe knife whenthe disc'is rotated. The additional mass may be provided'by making the blankof vheavier material and of a larger size.
Withea'ch rotation of the blade a slice of the speciifneumay be obtained, the thickness of which may beycontrolledby the Vrate of feed of the specimen relative Ytothe speed of rotation of the disc.J t
Having described the inventiomwhat I claim is: Y
1. Microtome blade mounting disc having a hub to receiveua spindle, an intermediate zone of decreasing'lthickness rand a Yperipheral margin of relatively less thickness, said margin having slots extending from thewperiphery of said disc inwardly at balanced positions relative to said disc, said disc having openings, one for each slot, entering "from one face to said slot, a plate in each 'said opening, vsaidplate having a pair of tapped" holes, and a pair of screws countersunk in the ina'rginof said vdisc from the face opposite said opening and threaded into said tapped holes of said-plate. v
2. Microtorne .blade mounting disc having a hub torec'eive a spindle, an intermediate zone of decreasing' thickness and a peripheral margin of relatively'lcss thickness, said margin having slots at balanced positions extending from the periphery ofsaid disc inwardly, said disc having a recess in one face of said margin and an opening from the opposite face to said slot, a screwholding plate in said recess, a clamping plate in said opening, said clamping plate having a pair of threaded holes, screws mounted in said plate and extendingthrough said slot into the holes in said clamping'plate. Y
3. The mounting disc of claim 1 in which said slots have one face in the mid plane of said disc.
4. :The mounting disc of claim 2 in which said slotsare at one side of the mid plane of said disc and in which said clamping plate enters from the face nearest'said slot.
5. Microtome cutting element which comprises a blade'mounting disc having a hub to receive a spindle, an intermediate zone of decreasing thickness and a peripheral margin of relatively less thickness, said margin having slots at balanced positions extending inwardly from the periphery, said disc having openings one for each slot, entering from one side face to said slot, a plate in each' said opening, said plate-having a pair of tapped holes,a blade for one of said slots having ashank mounted in said slot and having a pair -of'spaced i openings aligned with the openings of said plate and having an extension beyond the periphery of said disc sharpenedto a- Wedge edge at one side, and a pair of screws extending from the faceof said disc opposite said opening through the holes in said blade and into the holes in said plate and a balancing blank in the other of said slots.
6. Microtorne cutting Velement which. comprises a mounting disc having ahub to receive a spindle,
an intermediate Zone, of decreasing thickness and a peripheral marginof relatively less thickness,
said margin havingslots at balanced positions extending inwardly from the peripheryof Vsaid disc, said slots bein-g at one side of the .midplane of said disc, a cutting blade having a shank portion mounted in one of said slots and projecting beyondthe periphery thereof, means to secure said blade in said slot, the projecting part of said blade being sharpened to wedge shape toward the v mid plane or" said disc and the side face near said sharpened edge being cut away at a slight angle from the mid plane of said disc. ROBERT R. ALLEN.
` REFERENCES CITED The following references are of recordin the l file of this patent: Y
UNITED STATES 'PATENTS Number Name u Date 959,104 Barker May 24, 1910, 1,635,732 Wittv T Julya12, 1927 1,664,050 Sheehan Mar` 27, 1928 1,231,723V Molins r Oct. 15, 1929 1,860,197 Molins May 24, 1932 2,115,265 i "Jennett' Q Apr. 26, 1938