Abstract:
For automatic transportation and lifting and lowering of specimens in an automatic stainer, a drive system comprises a motor ( 16 ) and a side wall assembly ( 40 ), the motor ( 16 ) being coupled on the drive side to a first ( 12 ) and a second ( 14 ) crank system. The first ( 12 ) and second ( 14 ) crank systems are respectively coupled to the side wall assembly ( 40 ).

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims priority of the German utility model application 202 10 451.6 filed Jul. 5, 2002 which is incorporated by reference herein. 
     FIELD OF THE INVENTION 
     The invention concerns a drive system for an automatic stainer for staining specimens. 
     BACKGROUND OF THE INVENTION 
     In the microscopic examination of specimens, it is often necessary to mark certain parts or properties of the specimen by staining. In this way, for example, the structure in cells and tissues can be differentiated and made visible in high-contrast fashion. In order to emphasize structures selectively, it is necessary to adhere to certain staining procedures, called the “staining program,” which depend on the particular preparations to be treated and the specific properties to be examined within the preparations. In practical use, a standard staining process has proven successful (in addition to various special stains) for this purpose. In this so-called H.E. staining process, the specimens pass through a number of processing stages using xylene, alcohol, eosin, hematoxylin, acetic acid, and water. 
     Since the staining process is often very time-consuming, it is advantageous to stain a large number of preparations in a single staining program or to automate the entire staining operation. In the staining of histological preparations for microscopic examinations, for example, the physical and chemical properties of the structures in the cells and tissues are utilized for the binding of certain dyes. Both natural substances and synthetic dyes are used for histological stains. 
     A number of types of automatic stainers, which automatically convey the specimens to the respective processing steps, are used for staining specimens. The automatic stainers differ in terms of their mechanical configuration and manner of operation. 
     DE 41 17 831 and DE 41 17 833 disclose several automatic staining methods and apparatuses. In an automatic stainer of the Mediate company, a specimen slide holder containing the specimen slides with histological preparations is transported into treatment stations located one behind another. The preparations are then lowered into a treatment station (called a “trough”) and have applied to them an additional up-and-down motion that promotes complete staining. The motion mechanism of this device comprises two panels equipped with notches for receiving the specimens. One of these panels is located in front of the troughs and the other is located behind them. The two panels are each mounted on the frame of the device using a cross-type guide. A motor moves the panels, via a crank, in the vertical direction in order to extract the specimens from the reagent containers and lower them into the reagent containers. A second motor moves the specimens by way of a crank, when they have been extracted from the reagent containers, horizontally over the next reagent container. There they are lowered by a motion of the first motor. A third motor moves the panels, via a cam panel, vertically up and down in order to continuously mix the reagents. In this embodiment, two cross-type guides and three motors are required in order to perform the motions necessary for the staining process. The corresponding parts for motion transfer, and a number of sensors for each motor for position sensing, are additionally needed. 
     Also disclosed by the Shandon company is a staining device operating on the so-called carousel method. Here the treatment stations are arranged in a circle one behind another. The sequence in which the treatment stations can be traveled to is accordingly predefined. 
     U.S. Pat. No. 3,691,988 discloses a staining device for staining preparations that has a straight-line guide above the staining baths. A guide block that carries a number of preparations is arranged displaceably on this guide. That number of preparations is positioned by means of a chain drive, together with the guide block, over the desired staining bath and then lowered into the staining bath. 
     U.S. Pat. No. 4,911,098 additionally discloses an automatic staining apparatus that, using a gripper, can automatically lower into a staining bath a number of preparations that are to be stained. A tilting mechanism is provided for the gripper so that the chemical substances can easily drain off from the specimens being stained. 
     SUMMARY OF THE INVENTION 
     It is the object of the invention to propose an improved drive system for an automatic staining device, with which good staining results can be obtained even at high throughput rates. 
     According to the present invention, this object is achieved by way of a drive system for an automatic stainer comprising a motor ( 16 ); a side wall assembly ( 40 ) for carrying specimens to be stained; and a first crank system ( 12 ) and a second crank system ( 14 ) each coupled to the side wall assembly ( 40 ) and connected to the motor ( 16 ); wherein the motor ( 16 ) drives both the first and second crank systems ( 12 ,  14 ). 
     The drive system for an automatic stainer is thus characterized in that a motor is provided which is connected on the drive side to a first and a second crank system. The crank systems are in turn coupled to a side wall assembly of the automatic stainer that is designed to carry specimens. By way of this drive configuration, the first and the second crank system can be set in motion upon operation of the motor. Since the two crank systems are coupled to the side wall assembly, the motion of each of the crank systems is transferred to the side wall assembly. It is thus possible, using a single motor, to transfer to the side wall assembly of the automatic stainer a motion generated by the motor, different motion curves thereby being transferred via the two crank systems to the side wall assembly of the automatic stainer. 
     In a preferred embodiment, the two crank systems are mounted on a base frame of the automatic stainer. The crank systems each have a rotatably mounted shaft. Arranged at each of the end faces of the shafts are levers that extend parallel to one another. Each of the levers can have, at one of its ends, a rotatably mounted roller. The motor is advantageously arranged between the two crank systems, and on the drive side is in working engagement with the crank systems. The working engagement is preferably created by way of a toothed belt that runs from the motor respectively to the first and to the second crank system. With these two toothed belts, it is correspondingly possible to impose synchronous operation of the two crank systems. 
     To allow transport of the specimen preparations that are to be stained, there is provided on the automatic stainer a side wall assembly which has notches that are recessed, for example, into panels of the side wall assembly. The two panels are arranged parallel to one another and are joined rigidly to one another via transverse connections. At the two ends, each panel possesses a guide track. One of the crank systems can engage in each of these guide tracks, so that the motion of the crank system can be transferred to the frame. The guide track is preferably recessed into the frame by the fact that elements into which the guide track is recessed, in particular is milled, are attached onto the side wall assembly. Advantageously, these guide tracks have two surfaces that slope outward. 
     In a preferred embodiment of the invention, the rollers that are mounted rotatably on the cranks run in the guide tracks. Thus as soon as the motor begins to rotate, the rollers arranged and rotatably mounted at the ends of the cranks describe complete circles. Without additional actions, this complete-circle motion would of itself be transferred correspondingly to the side wall assembly. In order to lower the specimens that are present in the reagents vertically into the reagent containers and also pull them vertically back out, this complete-circle motion is trimmed. For that purpose, a gate is mounted rigidly on a base frame, and into it engages a peg that is attached to the side wall assembly. 
     With the use of the drive system according to the present invention, transport of the specimens in the automatic stainer can be accomplished using a single motor. The side wall assembly does not require a separate guide, since the drive mechanism that converts the rotary motion of the motor simultaneously provides guidance of the panels. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Further advantages and advantageous embodiments of the invention are the subject matter of the Figures below and the descriptions thereof, in which true-to-scale reproduction has been dispensed with in the interest of clarity. Specifically: 
         FIG. 1  is a perspective view of the drive system according to the present invention; 
         FIG. 2  shows a side wall assembly of the automatic stainer that can be coupled to the crank drive system; and 
         FIG. 3  is a perspective view showing the side wall assembly of  FIG. 2  coupled to the drive system of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  shows the drive portion of an automatic stainer  10  in a perspective depiction. The drive system for automatic stainer  10  is implemented by way of a motor  16 , a first crank system  12 , and a second crank system  14 . The two crank systems  12 ,  14  are connected to motor  16  on the drive side and are driven by toothed belts  18 . The two crank systems  12 ,  14  are of substantially identical construction. 
     Four bearing blocks  28  are attached for this purpose on a base frame  26 . Ball bearings  29  are pressed into bearing blocks  28 . Two shafts  20  are mounted rotatably by means of ball bearings  29 . Levers  19  are mounted rigidly on, in particular pressed onto, each of the ends of shafts  20 . At the free ends of levers  19 , a ball bearing  13 , onto which a roller  17  is set, is provided on a pin  11 . 
     Between bearing blocks  28 , toothed-belt pulleys  15  are arranged on shafts  20 . They are joined rigidly to the respective shaft  20 . From toothed-belt pulleys  15 , toothed belts  18  run toward motor  16 . A double toothed pulley  32  that drives toothed belts  18  is mounted on motor shaft  30 . Displaceable tension pulleys  34  can be provided for tensioning toothed belts  18 . Mounted rigidly on shaft  20  of second crank system  14  is a coding disk  36  with which an angle code can be identified and thus the exact angular position of shaft  20  can be ascertained. For that purpose, coding disk  36  can have, for example, an imprinted code that can be read by sensors. These sensors can, for example, be arranged on a board  38  or associated with board  38 . It is correspondingly possible, using this coding disk, to identify the respective present position of the entire transport mechanism, and thus to control the motion of the transport mechanism. Board  38  can, for example, be attached to base frame  26  using an angle bracket  39 . 
       FIG. 2  shows a side wall assembly  40  that can be coupled to the two crank systems  12 ,  14  as depicted in  FIG. 3 . Side wall assembly  40  has two panels  44  that form a lateral boundary of the side wall assembly. The two panels  44  are fixed in position with respect to one another at their long-side ends by transverse connectors  43  in such a way that they are aligned parallel. On each of panels  44 , guide tracks  24  are provided at the two lower ends. Advantageously, these guide tracks are machined into so-called assembly elements  41  that are connected immovably to panels  44  and thus to side wall assembly  40 . The assembly elements can be produced from any suitable material, in particular from sheet metal or a strong plastic. Guide track  24  extends in an outward-sloping fashion. As also depicted in  FIG. 1 , a gate  22  is additionally attached to base frame  26 . Gate  22  possesses a milled-in gate guide track  24  in which a peg  46 , attached to side wall assembly  40 , can engage. 
     As soon as motor  16  is put into operation, the drive-side connection of motor  16  to first and second crank system  14 ,  14  causes levers  19  to be moved out of their lower position. Because of the connection of side wall assembly  40  to the drive system, side wall assembly  40  follows that motion until peg  46  comes to a stop against the outer boundary of gate guide track  48  of gate  22 . At this point, panels  44  and therefore frame  40  are lifted vertically upward. Levers  19  continue to describe their circular path, and rollers  17  follow outward under guide track  24  of guide  41 . Since guide track  24  is tilted outward, a horizontal force component is created which pushes pin  46  against the outer side of gate guide track  48 . This prevents any horizontal motion of panels  44  during the lifting operation. As soon as roller  17  located on lever  19  approaches the upper reversing point of its circular motion, upper point  47  of guide track  24  snaps back onto roller  17 . Side wall assembly  40  then once again follows the circular path of rollers  17  until pin  46  touches gate guide track  48  on the other side of gate  22 . From that point on, side wall assembly  40  moves vertically downward. 
     PARTS LIST 
     
         
           10  Automatic stainer 
           11  Pin 
           12  First crank system 
           13  Ball bearing 
           14  Second crank system 
           15  Toothed-belt pulley 
           16  Motor 
           17  Roller 
           18  Toothed belt 
           19  Lever 
           20  Shaft 
           22  Gate 
           24  Guide track 
           26  Base frame 
           28  Bearing block 
           30  Motor shaft 
           32  Double toothed pulley 
           34  Tension pulleys 
           36  Coding disk 
           38  Board 
           39  Angle bracket 
           40  Side wall assembly 
           41  Assembly element 
           42  Guide 
           43  Transverse connector 
           44  Panel 
           46  Peg 
           47  Upper point 
           48  Gate guide track