US2872894A - Automatic immersion apparatus - Google Patents

Description

J. ISREELI AUTOMATIC ,IMMERSION APPARATUS Feb. 10, 1959 Filed Dec.

10 Sheets-Sheet 1 FIG. I

INVENTOR. Jck Bree/1' ATTORNEYS FIG.

A Feb. 10, 1959 ISREEL, 2,872,894

AUTOMATIC IMMERSIQN APPARATUS Filed Dec. 9, 1954 10 Sheets-Sheet 2 INVENTOR. Jae/Z [57'66/2' BYEMMi- ATTORNEYS Feb. 10, 1959 J. ISREELI' AUTOMATIC IMMERSION APPARATUS l0 Sheets-Sheet 5 INVENTOR. z/Zm/i' [area/z BY ma Filed Dec. 9, 1954 ATTORNEYS F 1959 J. ISREELI AUTOMATIC IMMERSION APPARATUS l0 Sheets-Sheet 6 Filed Dec. 9, 1954 FIG. 20

INVENTOR. Jbck Israeli ATTORNEYS J. ISREEL! Feb. 10, 1959' l0 Sheets-Sheet 9 Filed Dec. 9, 1954 FIG.39

FIG. 37

8 R2! 3 m E/ wf y 1 J 4 w 6 8 a 2 1 8 8 m: /M n A 2 1 1 B x IL 4 2 fl\ 1 w d rm im BY ecu. M .& m BL ATTORNEYS Feb. 10, 1959 Filed Dec. 9, 1954 J. ISREELI AUTOMATIC IMMERSION APPARATUS FIG.- 42

10 Sheets-Sheet 1O INVENTOR. (20k [area/1' BY 8% M ATTORNEYS AUTOMATIC IMMERSION APPARATUS Jack Israeli, 'iuclsahoe, N. Y., assignor to Technicon International, Ltd, New York, N. Y., a corporation of New York Appiication December 2, 1954, Serial No. 474,210 94 Claims. (Cl. 118-40) asmsst Patented Feb. to, was

tion and mode of operation of apparatus according to this invention are hereinafter described.

In the accompanying drawings:

Fig. 1 is a side elevational view of a single stack automatic immersion apparatus embodying this invention with portions thereof cut away to more clearly illustrate the construction of the apparatus;

Fig. 2 is a plan view of automatic immersion apparatus embodying this invention with portions thereof broken away to more clearly illustrate several features of this invention;

specimens and the staining of the sections which are mounted on microscope slides. More particularly, in the preparation of tissue, it is necessary to immerse the tissue successively in a plurality of liquid agents for certain lengths of time,.first to fix the tissue, then to wash the same for removing the fixative, then to dehydrate the tissue, usually by immersion of the tissue successively in a plurality of alcohols or other dehydration agents, then to immerse the tissue in a clearing agent, thereafter to infiltrate the tissue with an infiltration agent such as,

for example, paraflin, celloidin, etc. After the tissue is thus treated, it is cut into sections of desired thickness; then the paraffin or other infiltration medium is removed from said sections, usually by a solvent for the parafiin, after which the sections are mounted on the slides and stained.

One object of the present invention is to provide an automatic immersion machine which is of such construction that it is of reduced size and weight in comparison with previously known machines of the same and smaller capacities.

Another object of the present invention is the provision of mechanism of improved construction and operation for transferring tissue or other material from one receptacle to another of a series of receptacles.

A further object is the provision of simplified mechanism which is operable to move the material from an elevated position over one receptacle to a position over another receptacle in the operation of transferring the material from one receptacle to another and which is efiective for positively preventing lateral movement of the material when it is not in an elevated position.

Yet another object is the provision of improved mechanism for raising and lowering material in automatic immersion apparatus.

A still further object is the provision of improved devices for controlling the operation of automatic immersion apparatus.

An additional object is to provide means for preventing unintended displacement or movement of the liquid receptacles on their support.

Another object of the invention is the provision of automatic immersion apparatus that is more readily convertible from a single to a double stack machine than apparatus heretofore employed.

A yet further object is generally to improve the construction andoperation of automatic immersion apparatus.

Other objects and features of this invention will become apparent as the characteristic features of construc- Fig. 3 is a sectional view taken along the line 3-3 of Fig. 2;

Fig. 4 is a sectional view taken along the line 44 of Fig. 3;

Fig. 5 is a sectional view taken along the line 55 of Fig. 3;

Fig. 6 is a sectional view taken along the line 66 of Fig. 1;

Fig. 7 is a sectional view taken along the line 7-7 of Fig. 6;

Fig. 8 is a sectional view taken along the line 8-8 of Fig. 3;

Fig. 9 is a side elevational view looking along the line 9-9 of Fig. 10;

Fig. 10 is a sectional view taken along the line 10-10 of Fig. 9; I

Fig. 11 is a partial sectional "iew similar to Fig. 10 illustrating another condition of the novel intermittent rotary drive included in the automatic immersion apparatus;

Fig. 12 is yet another sectional view similar to Fig. 10 showing still another condition of the intermittent rotary drive included in this invention;

Fig. 13 is a partial enlarged view similar to Figs. 10l2 illustrating in more detail the contact actuator employed in this automatic immersion apparatus;

Fig. 14 is a sectional view taken along the line 14-14 of Fig. 13;

v Fig. 15 is a partial side elevational view looking along the arrow 15 of Fig. 2;

Fig. 16 is a sectional view taken along the lines 1616 of Fig. 15;

Fig. 17 is a sectional view taken along the line 1717 of Fig. 16;

Fig. 18 is a sectional view taken along the line 18-18 of Fig. 2;

Fig. 19 is a sectional View taken along the line 1919 of Fig. 18;

Fig. 20 is a plan view taken along the line 2020 of Fig. 18;

Fig. 21 is a partial sectional view taken along the line 2121 of Fig. 1;

Fig. 22 is a side elevational view taken along the line 22-22 of Fig. 21;

Fig. 23 is a plan view of a timing mechanism for controlling the automatic immersion apparatus embodying this invention;

Fig. 24 is a sectional view taken along the line 24-24 of Fig. 23;

Fig. 25 is a sectional view taken along the line 25-25 of Fig. 23 illustrating a locking means for the timing disc of the timing mechanism shown in Fig. 21;

- Fig. 26 is a sectional view similar to Fig. 25 showing the locking means in its locking condition;

Fig. 27 is a view similar to Figs. 25 and 26 showing a modification of the locking means in the timing mechanism;

Fig. 28 is a sectional view taken along the line 28-48 of Fig. 27;

Fig. 29 is a view similar to Figs. 25 and 26 showing another form of means for locking the timing disc in the ch ck mechanism shown in Fig. 23; i V

Fig. 30 is a side elevational view of automatic immersion apparatus embodying this invention having two tiers or stacks of receptacles, with some portions cut away to more clearly illustrate the construction of the apparatus;

Fig. 31 is an enlarged sectional view taken along the line 3l-31 of Fig. 21;

Fig. 32 is a perspective view illustrating the manner in which the material holders are mounted on their support;

Fig. 33 is a partial sectional view similar to Fig. 18 illustrating a material holder support provided withultrasonic transducer meansg i Fig. 34 is a sectional view taken along the line 34-34 ofFig. 20; i

Fig. 35 is a view similar to Fig. 34 showing the modification in the construction of the elongated slot cover;

Fig. 36 is a top plan view of a receptacle for parafiin, with some parts cutaway to more clearly illustrate the construction of the paraffin receptacle;

Fig. 37 is a sectional view taken along the line 37-37 of Fig. 36;

Fig. 38 is a partial elevation view looking along the arrow 38 of Fig. 37;

Fig. 39 is a view similar to Fig. 3, with several parts deleted, illustrating a modified means for biasing the con veyor to its lowest position;

Fig. 40 is an enlarged partial plan view of the locking member of the intermittent rotary drive mechanism illustrating the means for adjustably positioning the locking roller. thereon;

Fig. 41 is an enlarged partial plan viewof a conveyor employed in the automatic immersion apparatus disclosed herein illustrating the indexing means for positioning a material holder support on the conveyor;

Figs. 42 and 43 are circuit diagrams with more-or-less schematic illustrations of associated swichingdevices and illustrate the conditions for longer and shorter operating time cycles, respectively.

Referring now to the drawings in detail, the apparatus embodying the present invention comprises a housing or cabinet having a cylindrical base portion 12 and 'an upwardly extending dome shaped enclosure 14. The base portion 12, which primarily houses the timing mechanism to be referred toin detail hereinaften'is provided with two hinged doors 16 and 18. The portion of the base underlying the dome shaped enclosure 14 is open but has secured thereto a relatively strong disc-like plate 20 which overlies substantially all of the opening inthe base 12. The plate may be secured to the base by any suitable securing means such as welding or, as shown in Fig. 3,. by screws 21 and plate 20 is suitably secured to enclosure 14 as by screws 22 extending through dome shaped enclosure 14 and cars 24 on the plate 26.

Base 12 is preferably made of sheet metal and to stiffen the structure, three angle brackets 26 spaced 120 apart are secured to the side wall of base- 12 within the base in a suitable manner such as spot Welding, as indicated at 27 in Fig. 2. To further stiffen base'12, an angle iron 28 is secured to the bottom of thebase as by spot welding and extends around the entire periphery thereof. Angle ironZfi rests throughout its entire'extent on an oiled felt ring 3i) which is supported by a U- shaped member 32 of a sub-base 33. At a number of locations, U-shaped member 32 is provided with horizontal extensions 34 to limit relative vertical movement of base 12 and sub-base 33 to prevent inadvertent removal of the sub-base 33 from base 12. 'Furthermore, member 32 is provided with a plurality of apertures 35. A plurality of support elements 36 formed of rubber or similar. ma-

terial are secured to member 32 of the sub-basev by means of enlarged knobs 37 which are forced through.

apertures 35 and spread outabove the. apertures asbestseen in Fig. 31 to thus support the entire apparatus on a flat surface such as a table or desk top. Elements 36 have a sufficiently high ccefiicient of friction to resist movement of the sub-base on the table. With the above described support arrangement, base 12 can be rotated on sub-base 33 while the latter remains stationary. When the base is turned the horizontal portion of angle iron 28 slides over oiled felt pad 30 which does not produce an excessive amount of resisting frictional force. However, the friction between the angle iron and felt ring 36 is more than enough to prevent accidental rotation of the base.

The cylindrical base 12 has a substantially larger diameter than the diameter of enclosure 14 and the two are arranged concentrically. An inturned flange member 38 is secured to the upper part of the cylindrical wall of base 12 as by welding (Fig. 18). flange member 38 extends inwardly of base 12 to a point under enclosure 14 to form a platform or support for a plurality of receptacles 42 which contain tissue treating reagents. Preferably a fiat Bakelite ring 40 overlies the receptacle support 33 to resist corrosion by the liquids in said receptacles. Receptacles 42 are arranged in a circular row and are supported by the receptacle support 38 of cylindrical base 1238 best shown in Fig. 2. Each of said receptacles is provided with a front wall 44, a rearwall 46, and a pair of fiat side walls 48 which diverge as they extend from the rear to the front wall. The rear Walls as of the receptacles all abut against enclosure l4 to prevent movement of the receptacles toward the center of the circular rowc With this configuration for the receptacles, the receptacles can be brought into side-by-side relation to thus occupy a relatively small area for a given size of receptacles as compared with the cylindrical receptacles heretofore employed in such apparatus. For instance, for a given amount of liquid area per receptacle the total area occupied by the 12 receptacles shown in Pig. 2 is substantially reduced over that heretofore necessary when sub--- stantially cylindrical receptacles or beaker-s were employed since there is no waste space between the receptacles. Because of this configuration for the receptacles, the entire apparatus may be reduced in size and weight without reducing the size of the tissue holders and, accordingly, the capacity of the machine, as explained in further detail and claimed in respect to the broader aspects of this feature of the apparatus in the United States patent application of Nelson G. Kling, Serial No. 474,138, filed concurrently herewith and assigned to the assignee of my present application.

Preferably, although not necessarily, except for the beaker for the impregnating agent, paraffin, which will be described subsequently, the wedge shaped beakers are made of a suitable plastic material such as nylon, polytetrafiuoroethylene or polytrifluorochloroethylene, the latter two being purchasable under the trademarks Teflon and Kel-F, respectively. These materials are highly desirable because they do not undergo any physi cal or chemical changes as a result of contact with any of the liquid reagents used in the preparation of tissue since they are inert to the reagents. Furthermore, the beakers need only have wall thicknesses of about 4 of an inch as opposed to as much as 7X32 of an inch wall thickness necessary for the glass beakers of similar shape. With this substantial reduction in the wall thickness, these plastic beakers have a capacity which is approximately lOpercent greater than glass beakers of the same outer dimensions. Since it is well established that as the ratio of the volume of reagent to the volume of tissue increases, the effectiveness of the reagent on the tissue increases, the efliciency of'the entire apparatus is in- It will be obvious that either choice will result in highly beneficial effects.

According to another novel feature of the present invention, the wedge shaped receptacles 42 may be held in side-by-side relationship and prevented from moving either horizontally or vertically by novel stop means. In order to prevent substantial vertical movement of the receptacles, a narrow groove 50 is provided in each side wall of each receptacle so that when the receptacles are in side-by-side relation, the grooves in the sides thereof will cooperate to form relatively narrow channels 52. Secured to the side of the dome shaped enclosure 14 is a plurality of finger members 54 which fit into the channels 52 and thereby prevent substantial vertical movement of the receptacles 42. Furthermore, in order to prevent horizontal movement of the receptacles, hemispherically shaped buttons 56 are fixedly secured to Bakelite plate 4d) at each outer corner of a receptacle in such positions that if the receptacles are moved horizontally along the plate 4-0, they will engage their associated buttons and will not be able to move further outward in a horizontal direction.

With the receptacles or beakers in such close side-byside relation due to their wedge shape, means are provided for gripping the receptacles in order to remove them when desired. This means is provided herein by continuing the channels 52 along the sides of the receptacles and widening and deepening the grooves near front walls 44 so that there are substantially enlarged channels 58 at the front or wide ends of the wedge shaped receptacles which are adapted to receive the fingers of the operator or technician who is running the apparatus. The walls surrounding enlarged channels 58 are provided with ribs 59 to render the walls easier to grip when it is desired to remove one of the receptacles from the circular arrangement. In order to remove a receptacle from the circular arrangement as shown in Fig. 2, the

operator or technician need merely insert his fingersinto two adjoining channels 58 in order to grip the sides 48 of the receptacles and then move the receptacle upward the extent that the finger members and channel arrangement permit which is sufiicient to allow the bottom of the receptacle to clear the buttons 56 and thereafter pull the receptacle in a horizontal direction over the buttons and out from the circular arrangement.

The tissue to be treated for microscopic examination may be carried in any suitable material holder. Preferably, however, the tissue will be carried in material holders similar to that shown and described in a U. S. patent application of Edwin C. Weiskopf and Andres Ferrari, In, Serial No. 423,187, filed and assigned to the assignee hereof. These material or tissue holders 60 are made of some suitable material such as a phenolformaldehyde resin like Bakelite which is molded into a circular disc-like form with a perforated base 62 which has a slightly smaller diameter than the upper rim 64. The upper rim is provided with an annular groove 66 which is adapted to retain a perforated paper cover 68 in covering relationship after it has been pressed into the groove. The paper cover is provided with a tab '76 having a keyhole shaped aperture '72 therein. The tissue, of course, is placed in the Bakelite receptacle and the cover is thereafter pressed into the groove on the rim to close the receptacle.

To support a number of the aforedescribed material holders 60 for simultaneous immersion in a beaker, a support 74 is employed. Support 74 comprises a rod 76 and acircular flange or horizontal shelf 78 for said holders 6%. Said support 78 has three pin-like protrusions 8i) thereon spaced at 120 degrees to limit horizontal movement of said holders in relation to said support. Preferably, although not necessarily, the entire assembly is molded as one integral unit out of nylon, Teflon or KelF, although numerous other materials.

can be used. Furthermore, the assembly need not be one on top of the other.

molded but may be constructed out of separate com-- ponents. It is to be noted that with the material holders, their supports and the receptacles all made out of non-metallic material, with the exception of the paraifin bath which will be described subsequently, the tissue does not come into contact with any metallic element throughout its entire processing.

Rod 76 is provided with a narrowed throat 82 which is of such diameter that the narrow portion of the keyhole shaped aperture 72 can fit around it. The round enlarged portion of aperture 72 has a diameter which is slightly larger than the diameter of the rod 76 below the throat. Accordingly, when it is desired to position a tissue holder on a support, the tab 70 is aligned with throat 82 and the holder is moved horizontally until the round portion of aperture 72 registers with the rod, as best illustrated in Fig. 32. Thereafter, the holder is moved downward until base 62 rests on flange 78 between two pins 80. Thereafter, other tissue holders may be stacked Since there is room for three tissue holders to rest on flange 78, three stacks of tissue holders spaced 120 degrees from each other may be positioned on support 74 as best shown in Fig. 19. Certain features of the support 74 and tissue holders 60 are claimed and described in further detail in the U. S. patent application of Edwin C. Weiskopf and Andres Ferrari, Jr., Serial No. 474,218, and of Edwin C. Whitehead, Serial No. 474,244, both filed concurrently therewith and assigned to the assignee of my present application.

Support 74 is mounted on a conveyor 84. Conveyor 84 comprises a dome shaped circular carrier 86 and, at the center of the carrier, a depending thin walled hollow shaft 88. Carrier 86 is connected to shaft 88 to form conveyor 84 by any suitable means such as a removable pressed fit joint and a removable pressed fit pin 90 extending through both the top of the carrier and shaft 88. Shaft 88 extends through an aperture 39 in enclosure 14 and at the aperture is surrounded by an oil ring 91 which lubricates shaft 88 and prevents entry of dust and other foreign matter into the enclosure. Carrier 86 is provided with an annular groove 92 adjacent its outer peripheral edge. Furthermore, at each point where it is desired to suspend a tissue holder support 74 from the carrier indexing means 93 is provided to properly orient the tissue holder support relative to receptacles 42. This indexing means comprises a radial slot 94 extending from an aperture 95 in the groove 92 to the peripheral edge of the carrier is provided. A pair of horizontal arms 96 and 98 at right angles to each other are secured to rod 76 at its upper end. When the rod is properly positioned on the carrier, arm 96 will be positioned in groove 92 and arm 98 will fit into slot 94. The indexing or keying arrangement at the top of rod '76 and on the carrier together with the pin arrangement on flange "/8 all cooperate to insure that the tissue holders are properly positioned for introduction into the wedge shaped receptacle or beaker 42. It will be noted that any orientation of the tissue holders other than that shown in Fig. 2 will cause the tissue holder to engage the tops of the walls of the receptacles and thus prevent their immersion.

It will be noted that the diameter of rod 76 above throat 82 is substantially larger than the remainder of the rod. The rod is so shaped in order to readily adapt the entire apparatus for use in conjunction with ultrasonic vibrating means for accelerating the penetration of the tissue by the various reagents according to the invention. of Andres Ferrari, Jr. described and claimed in his U. S. patent application Serial No. 440,441, filed June 7 The structure of the tissue support below throat 82a is substantially the same as that of support 74 in Fig. 18. Above the throat rod 76:; is hollow and has mounted thereon, by any suitable means, ultrasonic vibrating means such as a magnetostrictive transducer 160. Power for the transducer is supplied over a pair of conductors (not shown) which preferably extend through the hollow portion of rod 76a to the transducer. It is because rod 76a is hollow above throat 82a and must support the added weight of the transducer that it must be larger than the remainder of the rod. Accordingly, in order to make the two types of supports interchangeable, rod 76 must also have the enlarged diameter above throat 82. The manner of controlling the supply of energy to the transducer is not within the scope of this invention.

As will be described in greater detail subsequently, conveyor 84 is movable in an up and down direction and also is rotatable about the longitudinal axis of shaft 88 for moving the tissue holder out of one receptacle and into another. In order to prevent evaporation and contamination of the various reagents a cover member 162 is provided. This cover member, as shown best in Figs. 1 and 2, is a flat member having a central opening 103 and a radial width which is slightly greater than the radial width of the receptacles. The large central aperture 103 of member 102 is of approximately the same diameter as the vertically extending part of enclosure 14. The cover is provided with a number of small apertures 1434 which register with a like number of apertures 1436 in the dome-shaped carrier 8-6. Slidably extending through apertures 166 are studs the heads of which are larger than the diameter of apertures 106 and the shanks of which are larger than the diameter of apertures M34. The shank ends of. the studs bear against cover 102 over apertures 104 and are internally threaded. Threadedly secure/.1 to studs 1% are screws 110 which have heads larger than apertures H84 and which extend through the cover apertures when in threaded engagement with the studs, thus fixing the studs relative to the cover. It will be seen that with this arrangement, when the conveyor is in its lowered position, cover N2 will rest on the tops of the receptacle walls to effectively cover the receptacles, thus preventing contamination and evaporation of the reagents. When the conveyor is raised, it will travel upwardly for a short distance while the cover remains on the beaker-s. apertures 106 moving longitudinally relative to the studs. When the carrier engages the heads of studs 1%, the upward movement of the conveyor will be transmitted to the cover for lifting the cover off the beakers.

With the cover mounted as just described, provision is made for removing the tissue holder supports without interference from the cover. To accomplish this aim, the cover is provided with a plurality of radial slots M2 extending from the outer periphery of the cover to point far enough in from the periphery to permit support rod 76 to extend therethrough ina vertical direction. Of course, the number of slots 112 preferably corresponds to the number of tissue holder support positions and, as shown herein, that number is twelve. To prevent evaporation or contamination of the reagents through slots 112, covering means for the slots are provided. This covering means comprises a fiat elongated member 114 having an upper portion 116 of width slightly wider than slots 112 and a lower portion 113 of slightly less width than slots 112 to fit therein for slidable movement, the wide portion 116 resting on top of the cover. Wide portion 116 is provided at one end with a concave curved portion 127 of the same curvature as rod 76 and portion 11.8 is provided with a convex curved portion 119 of the same curvature as the end of slots 112. When a rod extends through a slot 112 the associated member 114 is moved inwardly until the concave portion 117 of wide part 116 fits around rod 76 thus effectively eliminating anyopening in thecover member 102. When 8. there is no rod extending through the slot, the member 114 is moved further inward until the convex end 11? of narrow portion 113 fits against the end of the slot,

thus effectively covering the entire slot. When it is desired to remove a tissue holder support from its mounted position on conveyor 84, cover member 114 is slidably removed from cover 102 and thereafter the support is raised to detach it from carrier 86 and moved radially outward through the slot together with the corresponding receptacle.

Fig. 35 shows a modified structure for member 114 with provision for positively preventing vertical movement of the member relative to cover 102. To accomplish this a third portion 12% similar in configuration to wide portion 116 is provided to sandwich narrow portion 118 therebetween thus defining a pair of longitudinal grooves on the member. When in position in the slots 112, the outwardly extending part" will lap over and under the cover adjacent the slots to prevent vertical movement of member 1M relative to the cover. The outer end of lower portion 129 is shorter than portions 116 and 113 so that it does not engage the top edges of receptacles 42 which would result in preventing the cover 102 from seating properly on the tops of said receptacles.

The infiltrating agent commonly used to infiltrate tissue so that it can be out into sections for mounting on slides is parafiin, which, as is well known, is solid at room temperature. Accordingly, means must be provided in the receptacle for the paramn for heating it to a temperature at which the paraflin will be sufficiently liquid to effectively infiltrate the tissue. Accordingly, a novel beaker or receptacle 3.22 has been provided to contain the infiltrating agent. Beaker 122 is best shown in Figs. 3638. This beaker 122 has substantially the same configuration a the aforedescribed beakers 42, except that it is approximately one-fourth of an inch shorter than the beakers 42 as shown in Fig. 1. With beaker 122 shorter, cover 1tl2'will rest on the tops of beakers 42 but not on the top of beaker 122 thus preventing the cover from coming into contact with the paraffin. Another advantage of keeping the cover out of covering relationship with the parafiin beaker 122 is that parafiin itself at the temperature to which it is heated herein is not particularly volatile but any of the other reagents will be relatively volatile. Accordingly, any of the other reagents contaminating the parathn will evaporate and will be free to pass out of beaker $22 which, as already de scribed, is always uncovered.

Beaker ll); may be made of any suitable material but is preferably made of cast aluminum because of that materials excellent thermal properties. The beaker has two bosses 12-4 extending along the sides and bottom. These bosses are provided with circular bores or cavities 125 which have removably positioned therein heating elements 126. The front wall of beaker 122, rather than being 00th and curved as are the front walls of beaker 42 extends outwardly andthe upper surface of the protrusion is provided with a threaded aperture 123 which is adapted to threadedly engage a threaded collar 13th on a thermostatic control unit 132 so that the main body of the unit 132 is immersed in the paraffin. The thermostatic control unit may be of any suitable design but is preferably of construction substantially the same as that shown and described in the U. S. patent application of George Gorham, Serial No. 188,605, filed on October, 5, 1950, and assigned to the assignee hereof. An adjusting knob 134, mounted on a rotatable shaft 3.36 which extends into and is connected with the thermostatic control mechanism, is employed to calibrate control unit 132 as described in the aforementioned Gorham application. Shaft 136 is sufficiently long so that knob 13 5 will be positioned outside of an enclosure 138 mounted on the front wall of receptacle 122 to enclose the thermostatic control unit. To connect heating element 126 to unit 132 wires 140 extend therebetween. To give beaker 122 a neat appearance and to run the wires so that they will not be easily accessible to tamperers, a channel 142 is provided along the front wall of the receptacle adjacent the bottom and this channel is closed by enclosure 138. Accordingly, the wires extend out of view from the heater, through channel 142, upwardly within enclosure 138 to the thermostatic control unit. With heating elements 126 removably positioned in cavities 125, if they become defective for any reason, they may be removed readily and be replaced with relative ease, there being no necessity to disturb anything else on the heating receptacle other than enclosure 133.

As heretofore stated, conveyor 84 is movable up and down and rotatably in order to transfer the material holders from one receptacle to another. In order to effect the vertical movements of conveyor 84, a motor 144 having an integrally housed and connected reduction gearing 145 is provided. Shaft 146 which is the output shaft of the reduction gearing extends through a bracket 147 having a bearing 149 for shaft 146 and is connected directly to a crank 148 so that the crank will rotate with shaft 146. Bracket 147 is secured to plate 28 by suitable means such as screws 151. Crank 148 is connected to a link 1150 by means of a crank pin 152 and the other end of link 15% is connected to a member 154 at a point intermediate the two ends of said member. One end of member 154 is pivotally mounted on fixtures 156 as at pivots 158. It will be seen that when shaft 146 is rotated by the motor 144 through the reduction gearing mechanism, crank 148 will rotate so as to cause link 150 to move outwardly and upwardly as shown in the dotted positions in Fig. 3. With the link 1550 so moving in response to rotation of the motor, member 154 will pivot about pivots 158 from the position shown in solid lines in Fig. 3 to the uppermost dotted position shown in Fig. 3. Member 154 is provided with a roller 160 at its free end which roller engages the underside of a collar 162 fixedly mounted on hollow shaft Sit of conveyor 84 as by a pressed fit to cause the collar and shaft to move upwardly in response to the upward pivotal movement of member 154. With the roller 160 provided, the friction caused by the relative movement between collar 162 and member 154 is substantially reduced.

As may best be seen in Fig. 3, shaft 146 has connected thereon a bevel gear 164 which engages a companion bevel gear 166 which in turn is mounted on a rotatable shaft 168. As shown herein and as is presently preferred, the bevel gears 164166 are so proportioned that shaft 168 rotates at one-half the angular velocity of shaft 146. Fixed in any suitable manner on shaft 168 is a cam 170. A substantially vertically disposed member 172 is mounted on a pivot 174 which is mounted in bracket 147. Member 172 is provided with a cam follower 176 which is suitably secured to member 172 and is adapted to engage cam 17%. In order to insure that cam follower 176 is held in engagement with cam 170, both gravity and spring biasing means are employed. The gravity biasing means comprises a relatively heavy semicircular member 178 which is secured to member 172 below pivot 174 by any suitable securing means such as screws 180. With weighted member 178 so positioned, it will be seen that it will tend to rotate member 172 counterclockwise about pivot 174 thus maintaining cam follower 176 in engagement with cam 17%. Extending through weighted member 178 adjacent member 172 is a hole 182. A spring 184 having its uppermost convolution of greater diameter than the remaining convolutions and its bottom few convolutions of smaller diameter than the remaining convolutions is positioned in hole 182 with its top convolution bearing against the upper surface of member 178 adjacent the hole to limit the downward movement of the spring. A screw 186 having a head of greater diameter than that of the bottom convolutions is positioned in said spring in holding engagement with the convolutions of smaller diameter and threadedly engages a threaded aperture in bottom plate 20. The parts are so proportioned that spring 184 is under tension so as to bias cam follower 176 against cam 170. The tension of said spring can be adjusted by turning the screw 186 by a screw driver which may be inserted through the top of said spring. it is to be understood that either of the above described biasing means is efiective in and of itself to bias cam follower 176 against cam 17%. However, both means have been provided so that the apparatus will continue to function in the normal manner even if one of these biasing means should become defective. Cam 170 is so shaped that once per revolution of shaft 168 member 172 turns about pivot 17 4 from the position shown in solid lines in Fig. 7 to the position shown in dotted lines in that figure and back to the solid line position. It will be noted that in the position shown in solid lines in Fig. 7, a roller 188 which is rotatably mounted on the uppermost end of member 172 is in position to engage the bottom of collar 162 to prevent movement of conveyor 84 to the lowered position. With the conveyor 84 in its lowered position, when motor 144 commences operating, member 154 commences moving upward and roller engages the bottom of collar 162 to move the conveyor in an upward direction. During this time member 172 is in its retracted position as shown in solid lines in Fig. 3 so that collar 162 can move freely past roller 13% rotatably mounted on member 172. As collar 162 moves past roller 188, cam causes member 1'72 to move to the position shown in solid lines in Fig. 7, that is the position in which roller 188 prevents a downward movement of conveyor 84 by engaging the under side of collar 162. As the motor continues operating, member 154 commences moving in a downward direction but the conveyor is held in its raised position by the engagement of roller 183 with collar 162. The member 154 moves to its lowermost position as shown in solid lines in Fig. 3 and then commences a second movement upward until it once again engages collar 1.62. At this point cam 174) has rotated sutficiently to again impart motion to member 172 so that it pivots to the position shown in solid lines in Fig. 3 in which position roller 18% is out of the line of downward movement of the collar. Accordingly, as member 154 moves downwardly for the second time, the collar remains in engagement with roller 160 and the conveyor thus moves to its lowered position downward under the control of member 1534. As described herein, conveyor 84 moves downward due to its own weight which has been found to be satisfactory. If, however, it is desired to provide a more positive means for assuring that the conveyor will move downward and will not stick in its uppermost position, spring biasing means may be employed. As shown in Fig. 39, such spring means includes a helical spring 190 mounted at one end on pin 90 which secures carrier 86 to shaft 88 and at its other end on a pin 192 which is suitably fixedly mounted such as on a fixed shaft 193 to be referred to in more detail hereinafter. With the spring so mounted, each time conveyor 84 is moved to its raised position, spring 190 urges the conveyor downwardly toward its lowest position. It will be seen therefore that by employing a 2:1 ratio in the gearing 164466, the vertical movement of shaft 88 may be so controlled that for one rotation of shaft 163, the conveyor remains in its upper position for 50% of the time. The reasons and advantages for this type of movement will be described below.

In order to move the tissue holders laterally when they have been moved out of the receptacles in the manner just described, an improved intermittent rotary drive mechanism is employed. The intermittent rotary drive mechanism is mounted on a three armed spider 198 which is secured in underlying relationship to plate 20 by means of bolts 200 extending through the plate and through lugs 202 on the ends of the spider arms. Fixedly secured to spider 198 by means of a nut 204 is shaft 193 which is relatively stifr but preferably hollow. Disposed around shaft 193 at both ends thereof are sleeve bearings 195 and disposed'around the sleeve bearings for rotation relative to shaft 193 is a shaft 194. Each sleeve bearing is provided with a radially extending portion 197 which fits over the adjacent ends of the shaft 194 to thus position the bearings relative thereto. Shaft 1% is secured in any suitable manner to a driven member 1% for rotation therewith. The means for connecting shaft 1% to driven member 1% is also effective to prevent longitudinal movement of shaft 194. Shaft 88 of conveyor 84 fits over shaft 1%. Furthermore, shaft 194 is provided with a keyway 26:3 extending longitudinally thereof and shaft 33 is provided with a key 207 which is fixedly secured to shaft 88 as by rivets 2ii8'and which extends into the keyway. With suchan arrangement, it will be seen that conveyor 84 is movable longitudinally relative to shaft 194 but due to the aforementioned key and keyway arrangement, the conveyor rotates with shaft 1%. in order to impart motion to driven member 1% and shaft 194, a plurality of radial slots 210 corresponding in number to the number of receptacles used in the mechanism are spaced around the periphery of the driven member equidistant from one another. For instance, in the embodiment shown having 12 receptacles, there are 12 slots provided therein with each of the slots being spaced at an angular distance of from the adjacent slots. A driving member 212 is fixedly mounted on shaft M8 for rotation therewith. Driving member 212 is provided with a pair of angularly disposed arms 214 and 216, one of said arms, that is arm 214, having secured thereto a pin 218 having a roller 22th mounted thereon, said roller being adapted to fit into slots 210 in driven member 1%. When shaft 163 is rotated in a counterclockwise direction as shown in Fig. 10, roller 22% on arm 214 enters one of the slots 21% to commence rotation of the driven member 1% in a clockwise direction. The length of the arm 214 is so proportioned that roller 22% will be traveling normal to the curvature of the circle of member 196 at the point of entry thereby eliminating any necessity for chamferring the slots to permit the roller 226 to enter therein and also eliminating any initial shock as the roller enters a slot. As the rotation of shaft 168 continues the movement of rolier proceeds into the slot and to move the member 1% in a clockwise direction as heretofore stated.

According to one feature of the present invention, a novel means is provided for preventing movement of driven member 196 during the time roller 22% is not in any of the slots 21%. This means for preventing motion of the member when such motion is not desired includes a iocking member 222 which is pivotally mounted at pivot 22- which in turn is secured to plate 2%. Locking memoer 222 is provided with a stop pin 226 adjacent one end thereof, A spring 228 secured at one end to plate 29 is attached to the locking member 222 at its end opposite the end at which pin 226 is secured in order to bias the locking member toward the driven member 196. Positioned between pin 226 and pivot 224 on member 22-2 is an elongated slot 23%. Secured to member 222 through slot 23% is a pin 232 on which is rotatabiy mounted a roller 234 having a slightly smaller diameter than the width of slots 21% in member 196. Asshown in Fig. 40, the position of roller 23; may be adjusted Within the limits provided by slot 23% so that as roller 234 moves out of a slot 216, roller 220 moves into one of the slots 21% in order to prevent any movement of the member 1%. Pin 226 is provided to limit the movement of roller 234 into the slots in the driven member 1%. For reasons that will become clear hereinafter, when motor 14% becomes energized, driving member 212 is in the position best shown in Fig. 12, with roller 22%) being relatively remote from the slot 210 which it will enter for the next movement of the driven member 1%.

Accordingly, it will take a substantial period of time for member 212 to rotate to the point at which roller, 229 enters one of the slots 219A to rotate driven member 196 a fraction of a revolution, here preferred at 30. It will be understood that the slot just referred to as slot 213A and the slots hereinafter referred to as slots 2.103 and 216C are so designated merely to facilitate the description of operation of the mechanism, all of these slots being the slots 2% hereinbefore described. As roller 220 approaches slot 2143A in a direction normal to the curvature of the member 196 at slot 216A, the long arm 216 of member 212 engages the bevelled face 236 01. locking member 222 to move it away from the periphery of member and thereby move roller 254 out of slot 2112B. Wilth roller 234 out of slot 219B, member 195 is conditioned for rotation and as roller 22% moves into slot 210A, as best shown in Fig. 11, driven member 196 commences rotating in a clockwise direction.

riving member 212 continues rotating in a counterclockwise direction thus maintaining arm 216 in engagement with member 222. When the curved end of arm 215 comes into engagement with the bevelled face 236 of member 222, member 222 gradually moves toward driven member 1%, until roller 234 slowly comes into engagement with the periphery of member 196. It will be seen that by providing a bevelled face on member 223, the possibility of roller 234 rapping into engagement with member 196 as arm 216 moves out of engagement with member 222 is obviated and the movement of roller 234 into engagement with member 196 is gradual. it will be noted however that after roller 234 on member 222 engages the periphery of member r96 between siots EMS and ZlltiC the roller 22% on driving member M2 is still positioned in slot 219A and is still rotating the driven member 196 and hence shaft 194 in the clockwise direction. This movement continues until the slot ZiliiC becomes aligned with roller 23d and permits that roller to enter slot 210C under the urging of spring 228 to thereby stop rotation of member 1%. It will be noted however that this registering of the roller 234 with slot ZLiGC occurs at precisely the time that roller 22-0 on driving member 212 moves out of slot 216A and, accordingly, there is no possibility of any jamming of the mechanism due to a inisproportionin of the parts. As already stated, the position of roller 23- is adjustable. so that means are provided to insure that roller 234 moves into slot 220C at the desired instant. After partial rotational movement of member 1% is completed, shaft 1-68 and member 212 continue rotating until arm 216 engages a contact actuator 233 at which time a switch will be 0perated to de-energize motor 144 in a manner to be made more clear hereinafter. As clearly shown in the drawings, the intermittent rotary drive is located at the base of shaft 194 and adiacent the top of base 12. By so disposing the rotary drive, shaft 163 is relatively short and stiff, thus permitting a substantial reduction its diameter. Furthermore, this disposition of the rotary drive adds to the general compactness of the entire apparatus since the bulky supports heretofore used for the rotary drive are eliminated. in addition, with shorter connections from the motor to the drive, the necessary tolerances in machining are decreased thus decreasing the costs of fabrication.

in order to pivotaily mount a contact actuator 22-3 for partly controlling motor 144 in a manner to become clear subsequently, one of the lugs 2:22 on spider we, is much shorter than the other two, thus providing room for such mounting between the top of the short lug and the bottom of plate 2d as best seen in Fig. 14. Contact actuator 238 is biased by a spring 24 2 so that it tends to rotate counterclockwise. The contact actuator is provided with a cam portion or face 24- and an 2% extending outward and away from the can portion. Arm 24-65 has a depending part 248 provided with. two threaded apertures 250 and 252. Threadedly engaged in apertures 250 and 252 are screws 254 and 256, respectively, having tapered ends which are adapted to engage under certain conditions of the contact actuator the rollers 253 and 260 of microswitches 262 and 264, respectively, to operate said switches between their two circuit controlling condition. Micro-switch 262 is employed to control motor 14d during both the dehydrationinfiltration cycle heretofore mentioned and the relatively Short staining cycle to be referred to in more detail hereinafter. Micro-switch 264 is employed to control the energization and de-energization of the clock motor in the timing mechanism which controls the staining immersion cycle, switch 264 being out of circuit when the apparatus is operating on the dehydration-infiitration immersion cycle. The reason for this will also become clear hereinafter. Sufiice it to say at this point that with the screws 254 and 256 threadedly mounted as described above, the position at which they operate their respective switches can be readily adjusted. lf desired, lock nuts 266 may also be threadedly mounted on screws 254 and 256 to lock them in their desired positions. Furthermore, the came face on actuator 238 is so shaped that when arm 216 of driving member 212 engages said face, the contact actuator turns clockwise against the bias of spring 242 as arm 216 moves from point A to point B, actuator 233 remains stationary as arm 216 moves over the constant radius portion from B to C, and it moves counterclockwise under the urging of spring 242 as arm 216 moves from point C to D. Screws 254 and 256 are so adjusted relative to switches 262 and 264, respectively, that as arm 216 moves over the cam face the following events occur in the stated sequence: prior to arm 216 engaging the cam face, switch 262 is in its first circuit controlling condition and switch 264 is open; just after arm 216 passes point A, switch 264 is closed; just'prior to arm 216 reaching point B, switch 262 is op erated to its second circuit controlling condition; just after arm 216 passes point C, switch 262 is restored to its first condition; and when arm 216 reaches point D, switch 264 is open. The manner in which the switches control the automatic immersion apparatus will become clear as this description progresses.

Referring now to Fig. 7 another feature of this invention is illustrated. According to the feature illustrated in Fig. 7, when the conveyor 84 is in its lowermost position thereby causing the material holders to be immersed in the liquid in the receptacles, collar 162 rests on a cam 268 which is rotated by a motor and unitized reduction gearing 270. Motor 270 is preferably continuously energized throughout the entire operation of the machine, it being controlled only by suitable circuit controlling means such as an ordinary knife switch (not shown) mounted on base 20. With collar 162 resting on cam 268 which is being rotated by motor 270, the cam causes conveyor 84 to vertically reciprocate through a short stroke to thereby cause the tissue holders to vertically reciprocate through a corresponding stroke. As already described in detail in a copending U. S. patent application of Edwin C. Weiskopf and Andres Ferrari, In, bearing Serial No. 358,812 and assigned to the assignee hereof, the vertical reciprocation of tissue holders in the liquids tends to increase the penetration of the liquids into the tissue and decrease necessary immersion time.

For controlling the above described apparatus through the successive movements for immersing the tissue holders successively in the plurality of liquids, timing mechanisms 272 and 274 are employed. Timing mechanism 272 is used to control the operation of the apparatus when the latter is used to dehydrate the tissue and to infiltrate it with paraffin preparatory to cutting the tissue into sections to be mounted on the microscope slides. The total time for so preparing the tissue is of the order of about 24 hours and, accordingly, timing mechanism 272 is adapted to make one revolution each 24 hours. The total time necessary for staining the tissue sections is of the order of about one hour and, accordingly, timing mechanism 274 is adapted to make one revolution in an hour. With the one exception heretofore noted, the two timing mecha nisms are of the same construction. According to one feature of this invention, for conveniently setting the timing devices and for maintaining them in good working condition, each of the timing devices is mounted in a horizontal position on a bracket 276 which in turn is suitably mounted on one of the doors in the base. More particularly, mechanism 272 is mounted on door 16 and mechanism 274 is mounted on door 18 so that each may be removed outward of base 12 by merely opening the doors, thus pivot-ally moving the mechanism out of the base.

These timing devices operate substantially in the same manner as the devices shown and described in a patent granted to Edwin C. Weiskopf, No. 2,157,875, and assigned to the assignee hereof. Referring particularly to Figs. 2l--29, each device contains a conventional clock motor 273 which causes a shaft 280 to rotate at the predetermined speed depending on whether the clock is for the 24 hour cycle or the 1 hour cycle. Shaft 280 is connected to a flanged bushing 282 by means of a pin 284 which extends through the bushing and shaft. Accordingly, rotation of shaft 280 imparts rotational movement to bushing 282. Bushing 282 is connected to a plate 286 by any suitable means such as screws 288 so that plate 286 rotates with shaft 280 and bushing 282 at the predetermined rotational speed. Plate 236 extends outwardly from the flanged bushing 282 and is substantially fiat throughout. Extending upwardly from the bushing 28?. are a pair of parallel ears or plates 29%. Pivotally mounted between plates 290 are a pair of locking dogs 292 and a locking arm 294 having at the end adjacent the locking dogs a cam member 296. The locking dogs 292 are biased upwardly to a non-locking position by a spring 297. With the locking arm 294 in its vertical or nonlocking position and locking dogs 292 in their non-locking positions as best shown in Fig. 25, a timing disk 298 having a central aperture therein may be placed over the plate 286 to rest thereon with the aperture in the timing disk fitting around the parallel plates 290 and the locking dogs. The timing disk may be made of any suitable relatively stiff material such as metal, pressed fiber, wood or stiff cardboard and is so proportioned that it extends outwardly from the edge of plate 286 as may best be seen in Fig. 23. In order to hold the timing disk in place a spider 300 having a circular peripheral rim 302 of substantially the same radius as plate 286 and a central hub 304 with an aperture therein is placed over timing disk 29% so that locking arm 294 and plates 290 fit through the central hub aperture in the spider. Radially extending arms 306 here shown as three in number, connect the hub to the rim of the spider. The spider is so constructed that it has a slightly concave shape in its unstressed condition so that when it is placed in position over the tim ing disk, as heretofore described, only the rim 302 engages the timing disk, the remaining portions of the spider being disposed upwardly of said timing disk. With the spider placed over the timing disk, locking arm 294 can be pivoted clockwise so that cam member 296 engages locking dogs 292 and moves them downwardly against the bias of spring 297. The outer edges of the locking dogs engage hub 304 and exert a downward force against the spider to cause the latter to clamp the timing disk between it and plate 286. When the spider is in its final clamped position, as best shown in Fig. 24, only rim 302 on the spider will be effective for clamping the timing disk in position, the remainder of the spider remaining out of engagement with the timing disk. With such an arrangement, timing disk 298 will be clamped adjacent its outer peripheral edge where the clamping is most effective for preventing movement of the timing disk relative to plate 286. Furthermore, with the aforedescribed arrangement for clamping the timing disk in position, it will be seen that no removable parts are employed other than the spider itself. Accordingly, there is no possibility of any parts being misplaced prior to the beginning of operation of the machine when the machine is being set up by the operator or technician.

Figs. 27 and 28 illustrate another form of means for clamping spider 3% against timing disk 29% to hold the latter in fixed position relative to plate 236. In this form, locking dogs 292 are eliminated and in their place, a fiat elongated member 333 is placed against hub 304 of the spider. A clamping arm 312 is pivotally mounted on parallel plates 2% and is provided with an eccentric cam portion 314. When the arm 322 is vertically disposed as shown in dotted lines in Fig. 27, the raised part of cam portion 314 is out of engagement with member 368 thus removing the pressure on the spider to enable movement of the timing disk relative to plate 286. With arm 312 horizontally disposed, as shown in solid lines in Fig. 27. the raised part or" cam portion 314 engages member 3% to clamp the timing disk between the spider and plate. Although in the clamping arrangement shown in Figs. 27 and 28, member 398 can be removed, there is no necessity of its removal in order to properly position the timing disk since movement of the disk is possible with arm 312 in its vertical position, even though member 308 is resting against the hub of spider 36d.

If it is desired to use a removable threaded arrangement to hold spider 390 in position, an arrangement similar to that shown in Fig. 29 may be employed. Referring to Fig. 29, the flanged bushing 282 is provided with an upwardly extending threaded stud 316 which stud extends through the registered apertures of the plate 236, timing disk 298 and spider 30%. An internally threaded cap 318 is threadedly mounted on stud 316 and the cap can be moved downwardly by rotating it until it engages spider 3% and moves into the position shown in Fig. 29.

As heretofore stated, timing disk 298 is made of a relatively rigid material such as sheet metal, fiber board or a stiff cardboard. The timing disk has cut therein a plurality of V-shaped notches 320 at the angular distance corresponding to the amount of time it is desired to have a tissue holder remain immersed in a particular liquid held by the receptacles described heretofore. For instance, if the clock motor is designed to rotate the timing disk one revolution for each 24 hours and-it is desired to hold the tissue holder in a particular recep- I tacle for 1 hour, then the angular distance between'the two notches which define the beginning and end of this particular immersion will be spaced at of the arcuate distance of the entire timing disk, that is 15 apart.

'Pivotally mounted on bracket 276 is a sensing member 322 which has a free outwardly extending end 324 adapted to move into and out of notches 320. In engagement with member 322 'at the end opposite to end 324 is a limit switch 326 of any suitable design such as the well known microswitch. The spring in switch 326 which biases the contact actuator 327 of the switch into engagement with member 322 is efiective for biasing the member 322 against the periphery of the timing disk. The switch is so controlled that when end 324 is riding along the periphery of timing disk 298, the switch 326 is in one condition and when the free end of member 322 is in one of the notches 320, switch 326 is in another condition. The manner in which switch 326 functions to control the apparatus will be described subsequently. Suffice it to say for the present, when free end 324 of member 322 moves into a notch 320, switch 326 is operated to close an energizing circuit for motor 144 to cause the conveyor to move upwardly, to turn a fraction of a revolution and then to be lowered so as to transfer the material holders from one receptacle to another. 7

According to another of the features of this invention, a timing shut-off member 323 is pivotally mounted on the rim 302 of spider 309. Furthermore, detent means 329 are provided on the shut-0d member and the spider so that the shut-oil member may be pivoted between a first or retracted position in which the periphery of the shut-0E member is more or less coincident with the periphery of the spider, as shown in Fig. 23, and to a second or extended position in which the periphery of the shut-off member extends outwardly beyond the periphery of the timing disk, as may best be seen in Fig. 21. The shut-0E member in its distended or second position is adapted to engage the her 330 is pivotally mounted on bracket 276 and has a notched edge 332 which is adapted to engage a latch or pin 334 mounted on member 322 to hold member 322 out of engagement with the periphery of the timing disk. In order to insure that the latching will be accomplished, the latching member is biased by a spring 336 so that the edge of the latching member will always be in engagement with the latch 334. When end 324 engages the periphery of the distended shut-off member 328 and rides outwardly from the periphery of the timing disk along said edge, the latch 334 moves downwardly as viewed in Fig. 23 to permit the latching member 33!) to move to the right with the notched edge 332 riding over the top of latch 334. Spring 336 subsequently holds the latching member in the described position to prevent any return of end 324 into engagement with the periphery of the timing disk. For reasons which will become clear hereinafter in such a position microswitch 326 opens the energizing circuit for motor 144 and thereby prevents any further energization of that motor. .Therefore, any further movement of the conveyor and material holders is prevented. This shut-elf mechanism is particularly desirable since automatic immersion apparatus so provided may be set up on a Fri day night for operation over the weekend and when the cycle of operation is complete some time during the weekend, the machine will automatically shut off to prevent any further action. When the operator returns on Monday he may remove the tissue holders from the receptacles and reset the machine for daily operation. It is to be noted that one of the highly desirable features of the aforedescribed shut-off mechanism is the permanent pivotal mounting of the shut-off member on the spider. With such an arrangement, it will be seen that the shut-oh member cannot be removed from the spider in which removed condition it is possible for it to be misplaced or lost. With the present arrangement, the shut-off member is firmly and permanently mounted on the spider to prevent any loss thereof. Another feature of the shut-off mechanism is that the latch member is spring biased which permits the disposition of the entire timing mechanism any plane desired, for instance, in the horizontal plane as is shown in the preferred embodiment illustrated herein. In the event that a gravity bias were employed, it would be necessary to mount the timing mechanism in the vertical plane which would obviate the possibility of employing the convenient mounting on the hinged doors l6 and 18. Furthermore, with the timing mechanisms disposed in a vertical plane, the necessity of making the base 12 of the mechanism substantially larger would arise which, of course, would increase the cost of manufacture of the apparatus.

As heretofore stated, the operation of the automatic immersion apparatus for moving the tissue holders from one receptacle to another is initiated when end 324 of member 322 moves into one of the notches 320 on timing disk 2%. When motor 14-4 becomes energized shaft 146 commences rotating at a predetermined speed and shaft will commence rotating at a speed one-half the angular velocity of shaft 145 as already made clear. With the starting of rotation of these two shafts, shaft 146 imparts through crank 143 and link 159, the pivotal movement to member 154 which commences moving upwardly and causes roller to engage collar 162 and move conveyor 84 in an upward direction. At this time, member 172 is in its retracted position so that it does not block the upward movement of shaft 88 by engaging collar 162, and driving member 212 is rotating but has not as yet moved to the position in which roller 224i enters slot 210A to start turning member 196 and hence the conveyor 84. Conveyor 84 continues its upward movement to the uppermost dotted position shown in Fig. 3 at which time cam 178 actuates member 172 and rocks it to its blocking position so that as member 154 starts moving in a downward direction, collar 162 comes to rest on roller 188 to thereby prevent further downward movement of the conveyor. Member 154, of course, continues moving in a downward direction and furthermore, at this time, driving member 212 continues its rotary movement, but roller 228 has not as yet entered slot 216A. Accordingly, the carrier remains stationary in its raised position during the downward move of member 154 to thereby provide a period of dwell for the tissue holders over the receptacles they were just removed from so that the liquid on the material holders can drip back into the proper receptacle, thus reducing the contamination of one liquid by another. At approximately the time that member 154 reaches its downwardmost position, as shown in solid lines in Fig. 3, arm 216 of driving member 212 engages locking member 222 to move roller 234 out of slot 210B and roller 220 enters slot 210A to thereby impart rotary movement to member 196 and therefore to shaft 194. Through means of the key and keyway arrangement on shafts 88 and 194 the rotary movement of shaft 194 is imparted to shaft 88 which revolves with collar 162 moving on roller 183. During the rotary movement of conveyor 84, member 154 makes a second upward movement. At the time that the rotary movement is completed, roller 234 moves into slot 210C as heretofore described, and at approximately the same time member 154 again engages the 'unclerside of collar 162 and cam 170 causes member 172 to rock to its non-holding or retracted position to thereby permit the conveyor to move downwardly. Accordingly, it will be seen that conveyor 84 moves downwardly while collar 162 is resting on roller 160 of member 154 until collar 162 is engaged by continuously rotating cam 263 which commences to vertically reciprocate the conveyor. At this time arm 216 engages contact actuator 238 at a point between points A and B thereon and thereby operates switch 262 to deenergize motor 144.

It should be noted that the motor control system herein employed is a two switch, three wire control system similar to that used in the aforementioned Weiskopf Patent No. 2,157,875. In such a control system, each time a reversal of condition of either switch occurs, a reversal of the condition of the controlled mechanism occurs. For instance, as shown in Fig. 42, if motor 144 is deenergized, the operation of switch 262 or switch 326 energizes the motor. As heretofore stated, when free end 324 of member 322 drops into a notch 320 of timing disk 298, the condition of switch 326 is reversed so as to energize motor 144 which remains energized until shaft 168 makes approximately one complete revolution at which time arm 216 of driving member 212 engages pivotally mounted contact actuator 238 near point B to reverse the condition of switch 262 thereby deenergizing motor 144. Because clock 272 turns so slowly as compared with the time it takes arm 212 to make one revolution, end 324 of member 322 is still in the notch of the timing disk at the time motor 144 is initially deenergized at the completion of the material holder transfer. Subsequently, the timing disk moves sufliciently to lift end 324 along the angular face of the notch so that the condition of switch 326 is again reversed thus reenergizing motor 144. Motor 144 causes the outer end of arm 216 to move along contact actuator 238 to a point adjacent point C on its surface where, due to the contour of the cam face 244 of said contact actuator, the latter rotates counterclockwise to thus operate switch 262 for a second time, hence deenergizing motor 144 again. This second energizingdeenergizing cycle of motor 144, known as a reload cycle, is of very short duration and because of the lost motion in member 154 at the bottom of its path of movement, moves conveyor 84 an imperceptible amount or not at all. However, the reload cycle does condition the apparatus for the next transfer of the material holders from one receptacle to another so that when free end 324 of member 322 drops into the next notch 320, motor 144 will once again become energized to repeat the above described sequence of movements.

It will be noted that with a dwell period provided over each receptacle, the entire transfer cycle can be speeded up since the only limiting factor in the movement of the tissue holders from one receptacle to the other is a period of time sufficient to insure a predetermined amount of dripping of the liquid back into the receptacle from which the tissue holder has just been removed so that the liquids in the adjacent receptacles will not become contaminated.

'It is believed that from the foregoing description, it will also be clear that the ratio of rotational speeds of shafts 146 and 168 may be any desired ratio. For instance, if the shafts have a 1:1 speed ratio, there is no dwell period, the rotary movement commencing towards the end of the upward movement of member 154 and finishing towards the beginning of the downward movement of member 154. If the ratio is, for instance, 3:1, then member 154 moves conveyor 84 upward Where member 172 holds it and then member 154 makes two upward and downward moves without any effect upon the apparatus. Thereafter, member 172 is moved out of its holding position to permit the downward movement of the conveyor 84. Accordingly, in a 3:1 movement the dwell period takes up approximately or 42% of the time of a complete cycle of upward, lateral and downward movements of the tissue holders as compared with a 25% dwell period when a 2:1 ratio is employed. When operating the automatic immersion apparatus on the one hour or staining cycle, timing mechanism 272 is switched out of the control circuit for motor 144 and timing mechanism 274 is switched into the control circuit, see Fig. 43. With the switching of timing mechanism 274 into the control circuit, microswitch 264 is also connected into a control circuit for the clock motor of timing mechanism 274. This latter control circuit is so arranged that when switch 264 is closed, the timing mechanism motor is energized and when switch 264 is open, the clock motor is deenergized. Referring to Fig. 13, during the period of immersion in one of the staining liquids, arm 216 of member 212 is in engagement with contact actuator 238 at a point between locations C and D thereon. In such a position, motor 144 is deenergized and switch 264 is closed thus energizing the clock motor of timing mechanism 274. When free end 324 of member 322 falls into a notch on the timing disk of timing mechanism 274, the condition of switch 376 which functions in the same manner as switch 326 of timing mechanism 272 is reversed to energize motor 144. Accordingly, shaft 168 starts rotating to turn driving member 212 of the intermittent rotary drive. Accordingly, arm 216 moves along the cam face of actuator 238 past point D at which point actuator 238 has turned counterclockwise a sufiicient amount to open switch 264 and hence deenergize the clock motor of timing mechanism 274. Therefore, the timing disk ceases rotating and the end 324 of member 322 remains in the notch on the timing disk. Conveyor 84 moves upward, laterally and downward in the same manner as heretofore described. At about the time the conveyor is returned to its lower position, arm 216 of driving member 212, which has been rotating in a counterclockwise direction, comes into engagement with contact actuator 238 and as it moves by point A of the cam face thereon, the actuator rotates clockwise so as to close switch 264 and reenergize the clock motor of timing 19 mechanism 274. Arm 216 continues moving along the cam face until it is just in approach to point B thereon where, as already stated, contact actuator 238 is moved sufiiciently counterclockwise to reverse the condition of switch 262 and thus deenergize motor 144 to discontinue movement of the conveyor. With the timing mechanism reenergized, the timing disk rotates until it moves end 324 out of the notch at which time switch 376 reverses its condition. Accordingly, motor 144 again becomes energized and thus causes arm 216 to move over the cam face of actuator 238 until it moves just past point C where the condition of switch 262 is reversed to again deenergize motor 144, in the same manner as described with regard to the reload cycle above.

The principal reason for deenergizing the clock motor during the time in the one hour cycle that the material holders are being transferred from one receptacle to another is due to the fact that the timing disk on mechanism 274 is turning at such a fast rate that free end 324 of member 322 may be forced out of notch 320 while the tissue is in raised position out of the receptacles. When end 324 is moved outward of the notch, it causes switch 326 to reverse its condition and thus deenergize motor 144, thereby stopping further movement of the conveyor.

With the conveyor stopped, further processing of the tissue would be discontinued and the required treatment of the tissue would not be completed. Of course, in the 24 hour cycle, because of the slow movement of the timing disk on mechanism 272, there is no possibility of the conveyor stopping in mid-air, except for the desired dwell period described above, and hence, no provision for deenergizing the motor in timing mechanism 272 is necessary.

In accordance with one of the objects of this invention, the machine disclosed herein is readily convertible from the single stack machine heretofore described to a double stack machine shown in Fig. 30. The double stack machine may be employed to double the capacity of the apparatus by treating twice as much tissue with the same reagents at the same time, the reagents in one stack of receptacles being the same as those in the other stack. On the other hand, if desired, the double stack apparatus may be operated so that one stack is idle during the operation of the apparatus.

The double stack machine shown in Fig. 30 employs the identical mechanism for moving the material holders up and down and laterally as was heretofore described with regard to the single stack machine. The double stack conveyor 338, however, is provided with a hollow shaft 340 which is longer than shaft 88. Mounted on shaft 340 for movement therewith are a lower carrier 86 and an upper carrier 344. Carrier .86 is the same as the carrier on conveyor 84 in the single stack arrangement and is mounted on shaft 340 in the same manner as it is mounted on shaft 88, that is by means of pin 90 in addition to the pressed fit. Upper carrier 344 is a flat disk-like member with a center aperture 346. Carrier 344 has a raised portion adjacent aperture 346 and this portion is pressed fit on shaft 340 to connect the two parts. To further insure a good connection, a fixed pin 348 extends through shaft 340 and the raised portion of carrier 344, thus positively connecting the two. Extending around carrier 344 adjacent its outer peripheral edge is an annular groove 350 which cooperates with radial slots therein to serve as a supporting and keying arrangement for material holder supports 74 as already described in connection with the single stack machine. Each carrier supports a cover 192 of the same construction and in the same manner as heretofore described.

Secured on the side wall of base 12 opposite brackets 26 therein are a plurality of apertured brackets 354, here shown as three in number, that are spaced from each other at 120 degrees, as best illustrated in Fig. 2. Extending through the apertures in the brackets aresupport rods 356 which are internally threaded at each end. Screws 358 threadedly engage rods 356 at the bottom in order to secure the rods to their respective brackets. Mounted on the support rods at their upper ends is a receptacle support 360. The receptacle support is circular in shape and has a horizontal portion 362 and a vertical portion 364. In order to mount the receptacle support on rods 356 and to secure it thereto, a number of brackets 366. one associated with each rod, are secured to portion 362 of the receptacle support in any suitable manner as by screws 363. Brackets 366 extend inward from the outer edge of horizontal portion 362 and the brackets are provided with apertures which are of slightly greater diameter than rods 356 from the bottom of the bracket to some intermediate point where the aperture narrows to a diameter substantially the same as the threaded aperture in rods 356. Accordingly, when the receptacle support is placed over rods 356 so that the apertures in the brackets 366 register with the rods, the support may be moved downward until the rods contact the narrowing points in the bracket apertures at which point the support will be prevented from further movement. To secure the receptacle support to the support rods, screws 370 are inserted through the bracket apertures and threadedly engage rods 356. To resist corrosion of receptacle support 360 by the liquids in the receptacles thereon, a flat Bakelite ring 372 similar to ring 40 may be placed in overlying relationship with horizontal portion 362 of the receptacle support.

Resting on the horizontal portion of receptacle support 360 is a plurality of beakers 42 which are the same as those used in the single stack machine. The inner or narrow wall of the beakers bear against the vertical portion of the beaker support which limits the beakers horizontal movement toward shaft 343. Secured to vertical portion 364 by suitable securing elements 374 are another plurality of radially extending finger members 54 which fit into the channels 52 defined by the grooves 55) in the side walls of the beaker to prevent substantial vertical movement of them. Furthermore, hemispherical buttons 56 are secured to Bakelite ring 372 to prevent horizontal movement of the receptacles as already described. From the foregoing discussion, it will be seen that a simplified double stack machine is disclosed.

Furthermore, with the double stack arrangement described, it is believed clear that the single stack machine described earlier in this application may be readily converted to the double stack machine described herein with little expenditure in time or money. In order to accomplish the conversion of the above described single stack machine to the double stack machine, only the following steps need be taken. Pin 90 is forced out of its connecting relationship with carrier 86 and shaft 88 and the carrier 86 is moved upwardly oh the shaft. Dome shaped enclosure 14 is disconnected from plate 20 by the removal of screws 22. Thereafter, enclosure 14 is moved off the plate 29 and out of enclosing relationship with the actuating mechanism and the lower part of shaft 83. Shaft 83 is then moved upwardly off shaft 194 and long shaft 340 is slidably moved downward onto shaft 194 until its collar 162 operatively engages the actuating mechanism. Enclosure 14 is then replaced over the actuating mechanism and reconnected to plate 20 by means of screws 22. Carrier 86 is then pressed downwardly onto shaft 340 to its intended position and pin 90 is inserted through the carrier and shaft 34% to positively hold the two in the desired relative position. Carrier 344 is then pressed downwardly onto shaft 346 to its desired position and pin 348 is inserted through carrier 344 and shaft 346 to hold them in the desired relative position. Thereafter, the support rods are connected to brackets 354 and the upper receptacle support 360 is mounted thereon to complete the conversion. It is to be understood that the above steps necessary to convert a single to a double stack machine need not be per-

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