US3831554A

US3831554A - Specimen agitator

Info

Publication number: US3831554A
Application number: US00374182A
Authority: US
Inventors: H Wilton
Original assignee: American Optical Corp
Current assignee: American Optical Corp; Leica Microsystems Inc
Priority date: 1973-06-27
Filing date: 1973-06-27
Publication date: 1974-08-27
Anticipated expiration: 1991-08-27
Also published as: DE2430945A1; JPS5038590A; JPS5654574B2; GB1444065A

Abstract

A motor driven agitator providing slow rotational movement of a specimen holder rack with momentary periodic motion in the direction of the rotational axis induces maximum penetration of a treating fluid into specimens held in porous capsules on the rack. A self-aligning, automatic engaging clutch arrangement permits the agitator cover with motor, to be conveniently removed and replaced without complex mechanical components or annoying delays caused by unsuccessful efforts to align separated driving and driven members.

Description

United States Patent 1191 Wilton Aug. 27, 1974 SPECIMEN AGITATOR Primary Exandner-Morris Kaplan T. B [75] lnvmor Henry Wilton uffalo N Y Attorney, Agent, or firm-Alan H. Spencer; W1ll1am Asslgneei American pt al Co po ation, C. Nealon; l-loward R. Berkenstock, 1

Southbridge, Mass. 22 Filed: June 27, 1973 L d f T l l motor nven agltator provr ing s ow rotationa [21] Appl' 374l82 movement of a specimen holder rack with momentary periodic motion in the direction of the rotational axis [52] U.S. Cl. 118/416, 118/53 i u s max mum p netration of a treating fluid into [51] Int. Cl. B05c 3/08 specimens held in p us apsules on the rack. A self- [58] Field of Search 118/416, 418, 425, 426, g g, ati ngaging clutch arrangement per- 1 18/417, 52-57; 117/ 109, 113 mits the agitator cover with motor, to be conveniently removed and replaced without complex mechanical [5 6] References Cit d components or annoying delays caused by unsuccess- UNITED STATES PATENTS ful efforts to align separated driving and driven mem- 2,539,s02 1/1951 Weiskopf 118/416 hers 2,845,044 7/1958 Cohen 118/425 10 Claim, 9 Drawing Flglll'es PAIENTED mszmn ,55

sum 10$ 2 PATENTEDwszmm saw 20? 2 aia ams a i an IHIIIIIII I SPECIMEN AGITATOR BACKGROUND OF THE INVENTION The present invention relates to an agitator, and more particularly to mechanical agitators for efficiently treating a plurality of specimens with a liquid.

Advanced microscopy'techniques frequently require that specimens being prepared for examination be subjected to treatment with one or, more liquids. Such specimens are usually treated with a succession of liquids with alternate wash or rinse. After treatment, conventional specimen preparation may include mounting or embedding and slicing to obtain a sample ready for examination.

It is of prime importance to obtain maximum contact and circulation of specimens with the treating liquid while using a minimum amount of liquid, i.e.,just sufficient liquid to surround the specimens being treated. The specimens being treated are generally placed in some form of porous container to prevent damage to the specimens, prevent agglomeration or clumping of specimens and enable identification of individual specimens to be maintained by isolation. It is very desirable to use the minimum amount of liquid in treatment, since it is standard practice to discard the treating liquids without re-use. Efficient circulation of the treating liquid through porous specimen containers and about the specimens is extremely desirable in order to minimize the time necessary for treatment. Since treating fluids are frequently extremely dilute solutions, efficient circulation is also essential to uniformly andthoroughly treat a plurality of specimens.

BRIEF DESCRIPTION OFTHE INVENTION AND DRAWINGS Thorough and continuous circulation of a treating fluid about a plurality of specimens can be obtained by slowly rotating one or more racks having a plurality of specimens in containers about an axis and periodically reciprocating the racks parallel to the axis of rotation. While the speed of rotation is generally not critical and is related to the diameter of the specimen holder rack, suitable speeds are usually within the range of 0.1 to 30 RPM. It is generally desirable to select a speed which provides a specimen holder velocity not substantially exceeding feet per minute. While continuous rotation is preferred, it may be desirable to alternate the direction of rotation periodically. Obviously, rotational motion in a given direction must be continued until at least one complete displacement has occurred. Periodic axial reciprocation of the specimens during rotation is conveniently obtained by a cam action by one or more protrusions acting on a cooperating member connected to the racks and rotating therewith. It is convenient to utilize a tapered or funnel-shaped base in the agitator assembly having three or more raised areas spaced equidistant with a conical-shaped member having the same number or a multiple thereof, of recessed areas in equidistant corresponding locations. During rotation of the rack, the conical-shaped member will periodically engage the raised areas and be axially displaced and periodically return to the lower position as the raised areas become aligned with the recesses.

It is not essential that the axis of rotation be vertically oriented although there are several advantages to such an arrangement. One advantage is that gravity may be used to provide the motivating force for the return half of the reciprocal motion and another is that a selfengaging coupling means may be conveniently used to connect the drive means to the rack drive shaft without proper alignment by the operator and will fall into engagement during rotation when orientation occurs.

FIG. 1 is a perspective view of the assembled agitator;

FIG. 2 is a bottom view of the cam member for transferring reciprocating motion to the specimens;

FIG. 3 is a front view, partly in section, along plane IIIIII of the cam, showing the cam in its lower most position;

FIG. 4 is a front view in section, along plane IV-IV of the cam, showing many of the inwardly tapering surfaces of the cam and closure when the cam is in the lower most position;

FIG. 5 is a front sectional view, along plane III-III of the cam, showing the cam in its elevated position;

FIG. 6 is an enlarged, exploded view showing the drive shaft, driven shaft, and coupling member;

FIG. 7 is a perspective view of the coupling member;

FIG. 8 is an enlarged front view of the drive shaft, driven shaft and coupling member prior to operative engagement; and

FIG. 9 is an enlarged front view of the drive shaft, driven shaft, and coupling member in operative engagement.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. I, a hollow body 1, preferably of a clear material such as glass or plastic, which enables the operator to observe the action of the contents, is attached to a mounting plate 2. In the preferred embodiment, the hollow body defines a cylindrical cavity having a longitudinal axis therethrough. The mounting plate is used to 'mount the agitator assembly in operative association with apparatus (not shown) to provide desirable liquids for treating specimens with holders 3. A closure 4 is attached to the mounting plate, more clearly shown in FIG. 3, and has an inwardly-tapering surface of revolution 5 with two pairs of diametrically opposed protrusions 6 (only one protrusion shown). It is desirable to form the closure with an opening near the center of the surface of revolution to act as an inletoutlet for liquids used in specimen treatment. Cam 8 has an outwardly tapering surface of revolution 9 adapted to meet with inwardly tapering surface of revolution 5 as shown in FIG. 4. FIG. 2 illustrates the bottom view of the cam showing the outwardly tapering surfaces 9. Recesses in the outwardly tapering surface 9 are formed by diametrically opposed planar surfaces 10. Planar recesses are preferred because they provide passages permitting liquid to pass from one side of the cam to the other. A driven shaft 11 is connected to cam 8 with its axis aligned coincident with the axis of the surface of outwardly tapering surface of revolution 9. Driven shaft 11 is adapted to position specimen holder racks 12 and has axially extending irregular portion 13 adapted to rotate racks l2 therewith.

Electric motor 14 is carried by cover 15 which may be secured to the hollow body 1 by screw 16. FIGS. 6, 7, Sand 9 illustrate the preferred means for connecting the motor 14 to driven shaft 11. Motor shaft l7has a pair (only one shown) of diametrically opposed pins 18 near the distal end thereof. Coupling 19 has a generally cylindrical shape with a bore 20 in one end thereof, adapted to loosely receive motor shaft 17. Elongated slots 21 are diametrically opposed and attach the coupling to the motor shaft and permit universal motion of the coupling. The elongation of slots 21 further permits axial motion of the coupling with respect to the motor shaft 17. In the other end thereof, an inwardly tapering surface 22 has a cavity 23 with an irregular intersurface 24 adapted to rotationally engage driven shaft 11 which is axially moveable therein. The end 25 of driven shaft 11 is tapered to assist in alignment and engagement with coupling 19.

In operation, specimens are placed in porous holders 3 which in turn, are supported by racks 12. The racks are conveniently positioned above cam 8 on shaft 11. It is not necessary that the racks must be full during operation, however, it is desirable that the racks have perforations to assist in providing uniform circulation of the liquid, particularly when the racks are full. In the event that less than a full rack is desired, it is recommended that specimens be evenly distributed in order to provide most effective circulation of the treating liquid. After the racks have been placed on shaft 11, the subassembly is inserted into the hollow body 1 and rests against closure 4. It is not essential that the cam be in any specific rotational orientation when inserted in order to obtain proper axial alignment of the driven shaft within the hollow body. Because the inwardly tapering surface of revolution of the closure meets with the outwardly tapering surface ofrevolution 9 of the cam and driven shaft is axially aligned therewith, the shaft will be substantially coincident with the axis of the agitator body. In the event that the subassembly is placed against the closure with the outwardly tapering surface of revolution in contact with protrusions 6, po-

sitioning the protrusions in a diametrically opposed relationship enables alignment of the driven shaft 11 to be maintained.

The operator next places on body 1, cover 15 which preferably has motor shaft 17 positioned to axially align with the longitudinal axis of body 1. It is not necessary for the operator to orient the irregular portion of cavity 23 with the irregular portion of driven shaft 11, since in the event of misalignment, coupling 19 will rest on top of the tapered end of driven shaft 11 as shown in FIG. 8. The tapered surface 22 of the coupling, in cooperation with the tapered end 25 of the driven shaft, assist in axially aligning the coupling to surround the distal portion of driven shaft 11 when properly aligned therewith. After the operator turns on the motor and the motor shaft begins to rotate coupling 19, the irregular portion of cavity 23 and the irregular portion 12 of shaft 11 will align during the first complete revolution of the coupling. Coupling 19 will drop down surrounding the distal portion of driven shaft 11 with the recess 23 as illustrated in FIG. 9 upon alignment of the respective portions. Following rotational engagement of cou pling 19 with driven shaft 11, cam 8 and racks 12 will be rotated. The rotation of cam 8 causes engagement of alternate portions of outwardly tapering surfaces of revolution 9 with a pair of diametrically opposed protrusions 6 as shown in FIG. 5. Engagement of the outwardly tapering surfaces of revolution 9 with protrusions 6 causes displacement of cam 8 in an axial direction. As rotation of the cam continues and the recesses formed by planar surfaces 10 become oriented with protrusions 6, cam 8 moves in an axial direction toward the inwardly tapering surface 5 of closure 4 until surface 9 is in engagement therewith. This camming action provides periodic reciprocating motion which is transferred to racks 12 during rotation of the specimen racks. An added feature of the preferred embodiment is derived from the pumping action which occurs as the cam 8 moves toward and away from inwardly tapering surface 5.

Since it is usually desirable to treat specimens with a plurality of liquids which are frequently alternated with washes, it is useful to have an inlet-outlet 7 located at the bottom of the closure 4 through which the liquids may be introduced and withdrawn.

The foregoing description of embodiments of the Applicants invention is given by way of illustration and not of limitation. The concept and scope of the invention is limited only by the following claims and equivalents thereof which may occur to others skilled in the art.

What is claimed is:

l. A specimen agitator assembly comprising a hollow open ended body, a closure for one end of said body, said body and closure being adapted to contain a liquid for treating a specimen, said closure having an internal inwardly-tapering surface of revolution, at least three equidistant raised areas on said inwardly-tapering surface, a rotary cam having a tapering surface of revolution adapted to cooperate with said inwardly-tapering surface, said cam having at least three equidistant recesses on said tapering surface on said cam to receive each of said raised areas, means to support at least one specimen within said body, said means being connected to said cam, and drive means to rotate said cam and said specimen thereby provides periodic reciprocal axial displacement of said specimen through the combined action of the raised areas and cam to provide circulation of the treating liquid.

2. The specimen agitator according to claim 1 wherein there are four raised areas on said inwardly surface and four recesses on said tapering surface on the cam.

3. The specimen agitator according to claim 2 wherein the raised areas have a hemispherical surface and the tapering surface of said cam has four regularly spaced planar surfaces providing said recesses.

4. The specimen agitator of claim 1 wherein said drive means includes an electric motor having a driving shaft, a coupling axially connected thereto, and a driven shaft, said coupling surrounding at least a portion of said driven shaft.

5. The secimen agitator of claim 4 wherein said coupling comprises a generally cylindrical member slidably and universally connected at one end to the distal end of said driving shaft, said cylindrical member having a recess in the opposite end thereof to slidably engage and surround a portion of said driven shaft.

6. The specimen agitator of claim 5 wherein said recess in the opposite end of the cylindrical member has an inwardly-tapering surface of revolution to assist alignment of said driven shaft.

7. The specimen agitator of claim 2 wherein said body has a generally cylindrical chamber therein and is positioned with the axis thereof generally vertical and said drive means includes a motor having a drive shaft, a releasable coupling attached to the distal end thereof and a driven shaft having at least a portion of one end adapted to be surrounded by said coupling, the other end of said driven shaft being connected to said cam and said driven shaft being substantially axially aligned with the axis of said cam whereby said conical member is rotated about the axis thereof and reciprocates in a direction parallel to the axis thereof in response to alternate engagement of said raised areas on said tapering surface of the cam.

8. The specimen agitator of claim 7 wherein said releasable coupling is a generally cylindrical member slidably and universally connected to said driving shaft at one end; the other end of said cylindrical member having a recess of generally increasing depth in a direction toward the axis thereof and an axially aligned cavity at the apex of said recess adapted to releasably engage said one end of said driven shaft to transfer rotational motion from said driving shaft to said driven shaft and to permit axial reciprocation of said driven shaft without disengagement.

9. The specimen agitator of claim 8 wherein the drive shaft has a pair of diametrically opposed pins extending radially outward from said driving shaft, said cylindrical member has a pair of diametrically opposed slots extended in an axial direction and to receive said pins, said cylindrical member having a bore in said one end, said bore being larger than said driving shaft to provide limited freedom of movement of said cylindrical memher, a cover to close the other end of said body with said motor being positioned to align said driving shaft in substantially axial alignment with said body and driven shaft, whereby said closure generally aligns said driven shaft and cam with the driving shaft, and gravitation forces act on said releasable coupling to engage it with said driven shaft during the first revolution of said driving shaft.

10. The specimen agitator of claim 8 wherein said closure has a passage therethrough at the apex of the surface of revolution to introduce and withdraw liquids for treating the specimen.

Claims

1. A specimen agitator assembly comprising a hollow open ended body, a closure for one end of said body, said body and closure being adapted to contain a liquid for treating a specimen, said closure having an internal inwardly-tapering surface of revolution, at least three equidistant raised areas on said inwardly-tapering surface, a rotary cam having a tapering surface of revolution adapted to cooperate with said inwardly-tapering surface, said cam having at least three equidistant recesses on said tapering surface on said cam to receive each of said raised areas, means to support at least one specimen within said body, said means being connected to said cam, and drive means to rotate said cam and said specimen thereby provides periodic reciprocal axial displacement of said specimen through the combined action of the raised areas and cam to provide circulation of the treating liquid.

9. The specimen agitator of claim 8 wherein the drive shaft has a pair of diametrically opposed pins extending radially outward from said driving shaft, said cylindrical member has a pair of diametrically opposed slots extended in an axial direction and to receive said pins, said cylindrical member having a bore in said one end, said bore being larger than said driving shaft to provide limited freedom of movement of said cylindrical member, a cover to close the other end of said body with saiD motor being positioned to align said driving shaft in substantially axial alignment with said body and driven shaft, whereby said closure generally aligns said driven shaft and cam with the driving shaft, and gravitation forces act on said releasable coupling to engage it with said driven shaft during the first revolution of said driving shaft.