Abstract:
The inventive device comprises a tool holder ( 1 ), which can be displaced in an x-direction, in a y-direction that is perpendicular thereto, and in a z-direction that is perpendicular to both the x-direction and the y-direction, and which can rotate about the z-direction. A solid matter dosing head ( 350 ), provided as a tool, is automatically attached in a removable manner to the tool holder ( 1 ) by means of a permanent magnet ( 351 ). The tool can be easily exchanged for another tool due to this automatic removable attachment of said tool to the tool holder ( 1 ) involving the use of a permanent magnet ( 351 ).

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application is a divisional application of Ser. No. 10/381,403, filed Mar. 24, 2003, which is a 371 of PCT/CH01/00598, filed Apr. 10, 2001. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     The present invention relates to a device having a tool holder, which can be displaced in an x direction and a z direction which is perpendicular to the x direction, and a first tool in the form of a metering head, which can be removably secured to the tool holder.  
         [0003]     Devices of this type are used, inter alia, for automatically metering substances into a plurality of reaction vessels or test tubes which are arranged, for example, next to one another.  
         [0004]     In a device which is known as Caco-2 Assay produced by Mettler Toledo Bohdan, Greifensee, Switzerland, there are two tool holders with different tools. The tool holders can be displaced in a horizontal x direction, a horizontal y direction which is perpendicular to the x direction, and a vertical z direction which is perpendicular to the x and y directions, and in this way can serve reaction vessels arranged next to one another under the control of software. One of the tools is designed for metering liquid as a metering head in the form of a four-needle head with four parallel hollow needles which can be spread apart. The other tool is a gripper for handling substance plates which have a multiplicity of recesses for holding substance. To weigh matter which can be handled by the device, there is a balance, on which, by way of example, a corresponding substance plate or a test tube is placed.  
         [0005]     Although the two fixedly installed tools do make it possible to handle liquids and solids, they do not, for example, allow a solid to be metered directly into a reaction vessel. Moreover, there are two tool holders which have to be able to move independently of one another, in which context it must be ensured that they do not collide with one another. Finally, accurate weighing out of a defined quantity of substance is relatively complex.  
       SUMMARY OF THE INVENTION  
       [0006]     In view of the drawbacks of the devices of the prior art which has been described above, the invention is based on the object of providing a device which allows a very wide range of forms of substances to be handled as simply as possible.  
         [0007]     This object is achieved by the device according to the invention as defined in the independent patent claim  1 . Preferred variant embodiments will emerge from the dependent patent claims.  
         [0008]     The essence of the invention consists in the following: a device comprises a tool holder, which can be displaced in an x direction and a z direction which is perpendicular to the x direction, and a first tool in the form of a metering head, which can be removably secured to the tool holder. It comprises at least one further, other tool, which can be removably secured to the tool holder as an alternative to the first tool and which has at least one part which can move actively and independently of the movement of the tool holder, it being possible for the securing and removal of in each case one of the tools to be carried out automatically.  
         [0009]     In the present context, the terms automatic securing and removal of a tool is understood as meaning that the securing and removal are carried out not by hand but rather by the device itself, at most under the control of an operator.  
         [0010]     The fact that the device comprises various tools with different functions which can automatically be secured to and removed from the tool holder as alternatives means that a very wide range of substances, solids, etc. can be handled without problems. Since there is in each case only one tool attached to the tool holder, there is no risk of different tool holders and tools getting in one another&#39;s way.  
         [0011]     The fact that the further tool has at least one part which can move actively and independently of the movement of the tool holder results in better and additional use options compared to a mechanically passive tool or a tool whose movement is dependent on the tool holder.  
         [0012]     In an advantageous exemplary embodiment, the metering head carries with it a storage container which contains all the substance which is to be metered. This eliminates the need for substance-feed hoses, etc. leading to the metering head or to the tool holder. This has the additional advantage that the metering head can move more freely, without being impeded by hoses, etc.  
         [0013]     In a preferred exemplary embodiment, the tool holder can rotate about the z direction. This in particular allows the tool to rotate through, for example, 90.degree., i.e. allows, by way of example, a multi-needle head having a plurality of hollow needles arranged next to one another to be used to meter substances, which may differ according to the hollow needle used, to vessels belonging to a matrix in rows, then allows the multi-needle head to be rotated through 90.degree and substances, which once again may differ according to the hollow needle used, to be metered to the vessels of the matrix in columns. It is thus possible for a different combination of substances to be metered to each vessel of the matrix in a simple way. Moreover, the rotation allows reaction vessels, starting-material bottles, etc. to be arranged over an area and not just on a straight line.  
         [0014]     Preferably, the tool holder can additionally be displaced in a y direction, which is perpendicular to the x direction and the z direction. This enables reaction vessels, starting-material bottles, etc. to be arranged over a larger area.  
         [0015]     In an advantageous variant embodiment, the tool is secured to the tool holder by means of magnets, in which case it is preferable, where there are two permanent magnets which attract one another, for one of the two permanent magnets to be arranged on the tool holder and the other of the two permanent magnets to be arranged on the tool, and for it to be possible for the action of the attraction between the two permanent magnets to be cancelled out by means of at least one electromagnet. Connecting tool and tool holder by means of magnets allows automatic securing of the tool to the tool holder, for example by the tool holder being guided over the tool and then lowered onto it or the tool holder being moved laterally onto the tool. Detaching the tool from the tool holder by activating the at least one electromagnet by means of current pulses also contributes to enabling the tool change to take place automatically.  
         [0016]     In alternative advantageous variant embodiments, the tool is secured to the tool holder by screw connection, by means of a bayonet catch or by means of a clamping connection, etc. Although these methods of securing are normally more complex to implement, they are relatively simple to automate, in particular if the tool holder can be rotated about the z direction.  
         [0017]     Preferably, one of the tools is a screw metering head, which comprises a screw which can rotate forward and backward about the z direction in a tube which is at least partially open at its lower end and which can be used to take up and dispense substance. A screw metering head of this type can be used for targeted removal of pulverulent or liquid substance from a storage vessel and also for targeted dispensing of this substance.  
         [0018]     Advantageously, the lower open end of the tube can be closed off by a diaphragm provided with holes, and there is preferably a ram, which runs on the screw and presses substance through the diaphragm as the screw rotates when substance is being dispensed, arranged in the tube. The use of a diaphragm leads to more uniform dispensing of substance, since the substance is forced uniformly through the holes in the diaphragm. This in turn has the advantage that metering can be carried out more accurately.  
         [0019]     Advantageously, one of the tools is a capsule-transporting head, by means of which a capsule can be picked up and released, preferably by suction. A tool of this type makes it possible to transport substances in capsules or similar containers.  
         [0020]     Preferably, one of the tools is a matrix-capsule-transporting head, by means of which capsules which are arranged in the manner of a matrix can be picked up, preferably by suction, and the capsules can be released individually, together or in groups. The matrix-capsule-transporting head also makes it possible to transport substances in capsules, it being possible for a large number of capsules which are arranged in matrix form to be handled at the same time.  
         [0021]     Advantageously, one of the tools is a capsule-handling head, by means of which at least one capsule can be picked up, which capsule can be opened in the tool, preferably by means of a hollow needle, and in which tool the contents of the capsule can preferably be mixed with another substance, in particular a solvent. The mixing can be effected, for example, by adding solvent to the capsule, sucking up substance and solvent from the capsule and returning the material which has been sucked up into the capsule. Alternatively, the hollow needle can also be used to suck substance out of the capsule and dispense it again at another location. The capsule-handling head according to the invention makes it possible to prepare even more successfully for chemical reactions outside a reaction vessel.  
         [0022]     In a preferred variant embodiment, one of the tools is a matrix-capsule-handling head, by means of which a plurality of capsules which are arranged in the form of a matrix can be picked up, which capsules can be opened in the tool, preferably using hollow needles, and in which tool the contents of one capsule can preferably in each case be mixed with another substance, in particular a solvent. The mixing can be effected, for example, by adding solvent to the capsule, sucking up substance and solvent from the capsule and returning the material which has been sucked up into the capsule. Alternatively, the hollow needle can also be used to suck substance out of the capsule and dispense it again at another location. The matrix-capsule-handling head also makes it possible to handle substances in capsules and to prepare for chemical reactions, it being possible for a multiplicity of capsules which are arranged in the form of a matrix to be picked up and processed simultaneously.  
         [0023]     In another preferred variant embodiment, one of the tools is a capsule-dispensing head, in which a multiplicity of capsules are stored and can be dispensed individually, together or in groups, it preferably being possible for the capsules to be opened in the capsule-dispensing head, and it even more preferably being possible for the contents of the capsules to be mixed with another substance, in particular a solvent, in the capsule-dispensing head. The capsule-dispensing head according to the invention makes it possible to prepare for chemical reactions largely outside a reaction vessel and means that the appropriate capsules or the contents thereof simply have to be added to the reaction vessel in order to carry out these chemical reactions.  
         [0024]     Advantageously, one of the tools is a needle head with a hollow needle, a multi-needle head with a plurality of hollow needles, which can preferably be displaced individually in the z direction and/or the distance between which can preferably be adjusted, a gripper, a lid opener, or a solids-metering head. Tools of this type are each known per se on their own and additionally increase the possible uses of the device according to the invention.  
         [0025]     Advantageously, one of the tools is a combination head having at least two identical or different tool parts, one of the tool parts preferably being a needle head, multi-needle head, gripper, lid opener, capsule-transporting head, matrix-capsule-transporting head, capsule-handling head, matrix-capsule-handling head, capsule-dispensing head, screw metering head or solids-metering head. This allows a plurality of method steps to be carried out in succession or simultaneously using a single tool.  
         [0026]     In a preferred exemplary embodiment, a balance, which can be used to weigh substance or capsules which has/have been taken up or dispensed by the tool, is arranged on the tool or on the tool holder.  
         [0027]     The fact that a balance is arranged directly on the tool or on the tool holder makes it possible to weigh a substance, a substance capsule or another object which has been taken up or dispensed without the substance, the substance capsule or the other object or the tool for this purpose having to be placed onto a separate balance. Weighing in situ means that the material to be weighed does not have to be displaced, yet it is not necessary for a balance to be arranged at each working position, e.g. under each reaction vessel. This significantly simplifies the weighing operation.  
         [0028]     A method for weighing out a desired quantity of substance using a device having a tool holder, which can be displaced in an x direction and a z direction which is perpendicular to the x direction, and a tool in the form of a metering head, which is secured to the tool holder, and a balance arranged on the tool or on the tool holder, by means of which substance which has been taken up by the tool can be weighed, is characterized by the steps that  
         [0029]     a) substance is taken up by the tool;  
         [0030]     b) the substance is weighed;  
         [0031]     c) the difference between the weighed value obtained and the desired set value is calculated; and  
         [0032]     d) if the difference lies outside the range of a desired level of accuracy, the tool is used to discharge substance or take up additional substance depending on this difference;  
         [0033]     steps b) to d) being repeated until the difference is equal to zero within the range of a desired level of accuracy.  
         [0034]     A similar method for selecting a capsule with a desired quantity of substance using a device having a tool holder, which can be displaced in an x direction and a z direction which is perpendicular to the x direction, and a tool in the form of a metering head, which is secured to the tool holder, and a balance which is arranged on the tool or on the tool holder and can be used to weigh capsules which have been picked up by the tool, is characterized by the steps that  
         [0035]     a) the tool is used to pick up a capsule containing substance;  
         [0036]     b) the capsule with substance is weighed;  
         [0037]     c) the difference between the weighed value obtained and the desired set value is calculated; and  
         [0038]     d) if the difference lies outside the range of a desired level of accuracy, the capsule is released again from the tool and a new capsule containing substance is picked up;  
         [0039]     steps b) to d) being repeated until the difference is equal to zero within the range of a desired level of accuracy.  
         [0040]     These two weighing methods which operate in accordance with the test principle make it easy to weigh out a desired quantity of substance or a desired object with the desired level of accuracy.  
         [0041]     Advantageously, the device according to the invention has a camera, which is preferably arranged on the tool holder and which can be used to film an area below the tool holder, as well as a control computer having an image-processing unit, which evaluates images which have been filmed by the camera, it preferably being possible for the displacement of the tool holder and, the selection, securing or release of one of the tools to be controlled on the basis of the evaluation result.  
         [0042]     In an advantageous alternative variant, the device according to the invention has an infrared analysis unit, which is preferably arranged on the tool holder and has an infrared transmitter, by means of which infrared waves can be radiated into an area below the tool holder, and an infrared sensor, which can be used to measure reflected infrared waves, as well as a control computer having a measured-value-processing unit, which evaluates the reflected infrared waves measured by the infrared sensor, it preferably being possible for the displacement of the tool holder and, the selection, securing or release of one of the tools to be controlled on the basis of the evaluation result. The precise way in which an infrared analysis unit of this type functions is described, for example, in U.S. Pat. No. 6,031,233, which is hereby specifically incorporated by reference in the present description.  
         [0043]     The camera or the infrared analysis unit, together with the control computer, allows the device to operate completely automatically without an operator having to evaluate the substance or capsule to be handled and then actively control the displacement of the tool holder and/or the selection, securing or release of one of the tools.  
         [0044]     Further advantageous tools comprise, for example, a sensor, e.g. a pH sensor, a bar code reader, etc.  
         [0045]     In an advantageous variant embodiment, the device according to the invention comprises a further tool holder for attachment of a further tool which can be displaced in an x direction and in a z direction which is perpendicular to the x direction, it preferably additionally being able to rotate about the z direction and/or to be displaced in a y direction which is perpendicular to the x direction and to the z direction. The second tool holder may be designed and controlled in the same way as the first. With two or even more tool holders with tools attached to them, it is possible to multiply the speed of the device; at the control, it must be ensured that the various tool holders and tools do not impede one another. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0046]     The devices according to the invention are described in more detail below with reference to the appended drawings and on the basis of exemplary embodiments. In the drawings:  
         [0047]      FIG. 1  shows a tool holder which can be displaced in all three spatial directions x, y and z on a linear axis system and can rotate about the z direction;  
         [0048]      FIG. 2  shows the tool holder from  FIG. 1 , having a needle head with a hollow needle as tool;  
         [0049]      FIG. 3  shows the tool holder from  FIG. 1 , having a needle head with four hollow needles which can be displaced with respect to one another as tool, the four hollow needles being at a minimum distance from one another;  
         [0050]      FIG. 4  shows the tool holder with needle head from  FIG. 3 , with the four hollow needles at a maximum distance from one another;  
         [0051]      FIG. 5  shows the tool holder from  FIG. 1  with a capsule-transporting head as tool;  
         [0052]      FIG. 6  shows the capsule-transporting head from  FIG. 5  when it is holding a capsule;  
         [0053]      FIG. 7  shows the capsule-transporting head from  FIG. 5  when a capsule is being placed in a reaction vessel arranged in a matrix;  
         [0054]      FIG. 8  shows the tool holder from  FIG. 1  with a matrix-capsule-transporting head as tool;  
         [0055]      FIG. 9  shows the tool holder from  FIG. 1 , with a gripper as tool;  
         [0056]      FIG. 10  shows the tool holder from  FIG. 1  with a lid opener as tool;  
         [0057]      FIG. 11  shows a section view of a tool in the form of a capsule-handling head with hollow needle;  
         [0058]      FIG. 12  shows the capsule-handling head from  FIG. 11  on the tool holder from  FIG. 1  with a closed capsule which has been picked up;  
         [0059]      FIG. 13  shows the capsule-handling head with a capsule which has been picked up as shown in  FIG. 12  during the addition of solvent after the capsule has been punctured by the hollow needle;  
         [0060]      FIG. 14  shows the capsule-handling head with punctured capsule as shown in  FIG. 13  when the capsule, which now contains dissolved substance, is being dispensed;  
         [0061]      FIG. 15  shows the tool holder from  FIG. 1  with a diagrammatically depicted matrix-capsule-handling head as tool and capsules arranged in a matrix;  
         [0062]      FIG. 16  shows a sectional view of a tool in the form of a first exemplary embodiment of a capsule-dispensing head having a multiplicity of stored capsules at the tool holder shown in  FIG. 1 ;  
         [0063]      FIG. 17  shows a sectional view of a tool in the form of a second exemplary embodiment of a capsule-dispensing head having a multiplicity of stored capsules which can be opened in the capsule-dispensing head, at the tool holder shown in  FIG. 1 ;  
         [0064]      FIG. 18  shows the tool holder shown in  FIG. 1  with a screw metering head as tool, with a diaphragm which has been pivoted away, in a partially sectional illustration;  
         [0065]      FIG. 19  shows the tool holder with screw metering head from  FIG. 18  with a diaphragm which has been pivoted under the screw, in a partially sectional view; and  
         [0066]      FIG. 20  shows the tool holder from  FIG. 1  with a solids-metering head as tool. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0067]    
       FIG. 1 
     
         [0068]     A linear axis system for holding and displacing a tool holder  1  comprises two guide rails  6 ,  61 , which run parallel to one another in the y direction and are anchored in a fixed position in a manner which is not illustrated. The first ends of the two guide rails  6 ,  61  are connected by a rotary rod  7 , which can be rotated by means of a stepper motor  71 . An upper running rail  5  is secured to the two guide rails  6 ,  61  in such a manner that it can be displaced in the y direction. The upper running rail  5  is fixedly connected to a lower running rail  51  by means of two end plates  52 ,  53 . As a result of the rotary rod  7  being rotated by means of the stepper motor  71 , in each case one toothed belt in the interior of the guide rails  6 ,  61  is driven, causing the running rails  5 ,  51  to be displaced in the y direction. In the present context, the term displacement in the y direction is to be understood as meaning both a displacement in the +y direction and in the −y direction (the opposite direction).  
         [0069]     Carriage  4  is secured to the two running rails  5 ,  51  in such a manner that it can be moved in the x direction. In the present context, the term movement in the x direction is once again to be understood as meaning both a movement in the +x direction and in the −x direction (the opposite direction). The carriage  4  is driven by a stepper motor  54  via a toothed belt arranged in the hollow upper guide rail  5 .  
         [0070]     A tool rod  3  is secured to the carriage  4  in such a manner that it can move in the z direction. In the present context, the term movement in the z direction is once again to be understood as meaning both a movement in the +z direction and in the −z direction (the opposite direction). In order for the tool rod  3  to be displaced, a stepper motor  31  is attached to it via a hollow plate  32 , and a toothed belt is arranged in the hollow plate  32  and the tool rod  3 .  
         [0071]     At the lower end of the tool rod  3  there is a rotary drive  2 , to which the tool holder  1  is secured. The tool holder  1  can be rotated both ways about the z direction, as indicated by the arrow c, with the aid of a rotary motor  21 . In order to secure and release a tool, the tool holder  1  substantially consists of a permanent magnet, in which an electromagnet is arranged.  
         [0072]     A camera  10 , which is directed downward in the z direction and can be used to film an area below the tool holder  1 , is attached to the tool holder  1 . The images which are filmed by the camera  10  are transmitted via a data line to an image-processing unit of a control computer  11 , which evaluates these images. The control computer  11  can then control the displacement of the tool holder  1  in the x, y, z and c directions by means of the motors  54 ,  71 ,  31  and  21  and the selection, securing or release of a tool on the basis of the evaluation results.  
         [0073]     The following consideration applies to the whole of the remainder of the description. If a figure includes reference symbols which are provided for the purpose of clarity of the drawing but these reference symbols are not mentioned in the immediately associated text of the description, or vice versa, reference is made to the corresponding explanations given in preceding descriptions of figures.  
         [0074]    
       FIG. 2 
     
         [0075]     In this case, a needle head  100  is removably secured as the tool to the tool holder  1  by means of a permanent magnet  101 . The permanent magnet  101  of the needle head  100  and the permanent magnet of the tool holder  1  attract one another, so that when the needle head  100  is removed it can be secured to the tool holder  1  by placing the tool holder  1  on it, an operation which can be performed automatically, i.e. the needle head  100  does not have to be attached to the tool holder  1  manually. The needle head  100  is detached from the tool holder  1  by means of the electromagnet which is arranged in the tool holder  1 , cannot be seen and, when it receives a current pulse, cancels out the action of the attraction between the permanent magnet  101  of the needle head  100  and the permanent magnet of the tool holder  1 .  
         [0076]     A linear drive  103  is attached to the permanent magnet  101  via a plate  102 . A hollow needle  105  is secured to the outer cylinder of the linear drive  103  by means of two holding parts  104 , which are provided with continuous receiving holes for the hollow needle  105 . With the aid of the linear drive  103 , the hollow needle  105  can be displaced in the z direction.  
         [0077]     A hollow needle  105  of this type can be used, for example, to meter or remove liquid substances into or from reaction vessels. In particular, for this purpose a suction and/or blowing means can be connected to the top end of the hollow needle  105 .  
         [0078]      FIG. 3  and  4   
         [0079]     The tool is in this case formed by a needle head  120  with four hollow needles  125 , which can be individually displaced in the z direction and the distance between which can be adjusted from a minimum distance a.sub.min to a maximum distance a.sub.max, the distance between each pair of adjacent hollow needles  125  always being identical. To this end, the hollow needles  125  are each secured to the outer cylinder of a linear drive  123  by means of two holding parts  124  which are provided with continuous hollow-needle-receiving holes. The linear drives  123  which can be used to displace the hollow needles  125  individually in the z direction are for their part in each case attached to an associated plate  122 . The four plates  122  are arranged movably in two grooves in a permanent magnet  121 , the drive for this purpose being effected by means of two spindles which are driven by a motor and are located inside the permanent magnet  121 . The needle head  120 , as described in connection with  FIG. 2 , is connected to the tool holder  1  via the permanent magnet  121 . Once again, the needle head  120  is detached from the tool holder  1  by means of the electromagnet (not visible) arranged in the tool holder  1 .  
         [0080]     A needle head  120  of this type can be used, for example, to successively meter different liquids to a reaction vessel or to meter liquid to or remove liquid from a plurality of reaction vessels simultaneously. In particular suction and/or blowing devices can be connected to the top end of the hollow needles  125  for this purpose.  
         [0081]      FIG. 5  to  7   
         [0082]     The tool is in this case formed by a capsule-transporting head  140 , by means of which a tightly closed capsule  150 , which is in the form of a small tube and contains a pulverulent substance  151 , can be picked up by suction. The capsule-transporting head  140  comprises a permanent magnet  141 , by means of which, as described in a corresponding way in connection with  FIG. 2 , it is connected to the tool holder  1 . It can be released by means of the electromagnet arranged in the tool holder  1 . A suction tube  143  having a capsule-holding end piece  144  is attached to the permanent magnet  141  via an intermediate part  142 . A reduced pressure can be generated in the suction tube  143  by means of a conventional suction means (not shown).  
         [0083]     To pick up a capsule  150 , the capsule-transporting head  140  is moved such that the capsule-holding end piece  144  is above the top end of the capsule  150 , and then the capsule  150  is picked up as a result of a reduced pressure being generated in the suction tube  143 , as illustrated in  FIG. 6 . Then, the capsule  150  is transported by the linear axis system to the intended location, in  FIG. 7 a  reaction vessel  171  arranged in a matrix  170 , where it is released into the reaction vessel  171  as a result of the reduced pressure in the suction tube  143  being eliminated.  
         [0084]    
       FIG. 8 
     
         [0085]     The tool is in this case formed by a matrix-capsule-transporting head  160  which comprises a permanent magnet  161 , by means of which, as has been described in a corresponding way in connection with  FIG. 2 , it is connected to the tool holder  1 . It is released by means of the electromagnet arranged in the tool holder  1 . Sixteen suction tubes  163 , which are arranged in the form of a matrix and each have a capsule-holding end piece  164 , are attached to the permanent magnet  161  via a suction-tube plate  162 . A reduced pressure can be generated in the suction tubes  163  via the suction-tube plate  162  by means of a conventional suction means (not shown).  
         [0086]     To pick up capsules  150 , the matrix-capsule-transporting head  160  is moved such that the capsule-holding end pieces  164  are above the top ends of the capsules  150 , and then the capsules  150  are picked up as a result of a reduced pressure being generated in the suction tubes  163 . Then, the capsules  150  are transported by the linear axis system to the intended location, in this case reaction vessels  171  arranged in a matrix  170 , where the capsules  150  are dispensed into the reaction vessels  171  as a result of the reduced pressure in the suction tubes  163  being eliminated.  
         [0087]    
       FIG. 9 
     
         [0088]     In this case, a gripper  180  is secured as tool to the tool holder  1  by means of a permanent magnet  181 . Once again, the gripper  180  is released from the tool holder  1  by means of the electromagnet arranged in the tool holder  1 . The gripper  180  comprises three gripper arms  182  which can be pivoted away from the permanent magnet  181  in the direction of the arrows illustrated. The pivoting drive is arranged inside the permanent magnet  181 .  
         [0089]     Similar grippers  180  of this type which, however, are fixedly connected to the tool holder  1  are already known from the prior art. They can be used, for example, to grip and transport solids.  
         [0090]    
       FIG. 10 
     
         [0091]     In this case, the tool is formed by a lid opener  200 , which comprises a permanent magnet  201 , by means of which, as has been described in a corresponding way in connection with  FIG. 2 , it is connected to the tool holder  1 . The lid opener  200  is released from the tool holder  1  by means of the electromagnet arranged in the tool holder  1 .  
         [0092]     On the one side, a motor  202 , which opens and closes, under computer control, a clamp  203  having two clamping arms  204  and  205  in the directions indicated by arrows A and B, is secured to the permanent magnet  201 . The clamp  203  engages around and holds a starting-material vessel  210  which is closed off by a lid  211 .  
         [0093]     On the other side, a strap  206 , to the free end of which a cap-like lid-gripping element  207  is rotatedly attached, and which can be folded up as indicated by arrow C, is articulatedly mounted on the permanent magnet  201 . The lid-gripping element  207  surrounds the lid  211  of the starting-material vessel  210  and is frictionally connected thereto. As an alternative, a positively locking connection would also be conceivable. To rotate the lid-gripping element  207  in the direction indicated by arrow D, a rotary motor  208  is attached to the strap  206 . Actuation of the rotary motor  208  causes the lid-gripping element  207  to be rotated, rotating the lid  211  with it via the frictional connection, with the result that the lid is detached from the starting-material vessel  210 . The strap  206  can then be folded up in the direction indicated by arrow C together with the lid-gripping element  207  and the lid  211 .  
         [0094]      FIG. 11  to  14   
         [0095]     In this case, the tool is formed by a capsule-handling head  220 , which comprises a cylindrical housing  221  which is divided into two compartments  223  and  224  by a partition  222  and is closed off at the top by an end wall  227 . At the open end of the bottom compartment  223 , in the cylindrical housing  221 , there is an air-filled sleeve  225 , for example made from rubber, which in the unladen state as shown in  FIG. 11  has an internal diameter da.sub.min. In the upper compartment  224  there is a plunger  226 , to which a plunger rod  228 , which projects out through the end wall  227  and is provided at its top end with an outer push-button  229 , is attached. Between the plunger  226  and the cylindrical housing  221  and between the plunger rod  228  and the end wall  227  there is in each case an annular seal  230 ,  231 . Between the plunger  226  and the partition  222  there is a coil spring  232 , which in the unladen state holds the plunger  226  in the position shown in  FIG. 11 . Between the plunger  226  and the end wall  227  there is an air-filled space  233 , which is in communication with the interior of the sleeve  225  via an air line  234 .  
         [0096]     In addition, the capsule-handling head  220  comprises a hollow needle  235 , to which an inner push-button  236  is attached. The inner push-button  236  is mounted movably in a recess  237  in the outer push-button  229 , a coil spring  238  being arranged in the recess  237  below the inner push-button  236 , which coil spring  238 , in the unladen state, holds the inner push-button  236  and the hollow needle  235  in the position shown in  FIG. 11 . The hollow needle  235  passes through the plunger rod  228 , the plunger  226  and the partition  222 . It is in communication with the internally hollow inner pushbutton  236 , which can be fed, for example, with a solvent or another liquid via a feed line  239 .  
         [0097]      FIG. 12  shows the capsule-handling head  220  after it has picked up a capsule  150 , an operation which can be effected by placing the capsule-handling head  220  onto the capsule  150 . The capsule  150  is held by the sleeve  225 , which now has an internal diameter d which corresponds to the external diameter of the capsule  150  and is greater than the internal diameter d.sub.min in the stress-free state.  
         [0098]      FIG. 12  also illustrates that the capsule-handling head  220  comprises a permanent magnet  240 , via which, as described in a corresponding way in connection with  FIG. 2 , it is connected to the tool holder  1 . The capsule-handling head  220  is detached from the tool holder  1  by means of the electromagnet arranged in the tool holder  1 . Moreover, the figure diagrammatically indicates that the inner push-button  236  can be actuated by a rotary lever  242  and the outer pushbutton  229  can be actuated by a rotary lever  244 , the two rotary levers  242 ,  244  being articulatedly mounted on a rod.  243 , which is secured to the permanent magnet  240 , in such a manner that they can rotate in the direction indicated by the arrows. The drives for the two rotary levers  242 ,  244 , which are controlled by the control computer, are not shown.  FIG. 11, 13  and  14  do not show the permanent magnet  240 , the two rotary levers  242 ,  244 , the rod  243 , and the tool holder  1 , for reasons of clarity.  
         [0099]     The coil spring  238  is compressed as a result of the inner push-button  236  being pushed downward, and as a result the hollow needle  235  is forced into the capsule  150 , as illustrated in  FIG. 13 . As a result, the capsule  150  is opened and it can be supplied, via the hollow needle  235 , with a substance from the inner push-button  236 , which is fed via the feed line  239 . Alternatively, the feed line  239  could also be connected directly to the hollow needle  235 . The substance supplied, in this case a solvent, can be mixed with the substance which is already present in the capsule  150 , for example by the capsule-handling head  220  being shaken. If a sufficiently long hollow needle is used, the mixing could also be effected by the substances which are present in the capsule  150  being sucked up and discharged again a number of times.  
         [0100]     If pressure is no longer being exerted on the inner push-button  236 , the coil spring  238  forces it back upward into the starting position.  
         [0101]     In order for the capsule  150  to be released, the outer push-button  229  is pressed downward, as illustrated in  FIG. 14 . In the process, the plunger rod  228  and the plunger  226  are moved downward so as to compress the coil spring  232 , with the result that the size of the space  233  between the plunger  226  and the end wall  227  is increased greatly and a reduced pressure is generated therein. This reduced pressure causes air to be extracted from the interior of the sleeve  225  via the air line  234 , with the result that the internal diameter of the sleeve  225  is increased to a maximum value d.sub.max, which is greater than the external diameter of the capsule  150 , so that the capsule  150  is no longer held by the sleeve  225  and drops downward under the force of gravity.  
         [0102]     If pressure is no longer being exerted on the outer push-button  239 , the coil spring  232  forces it back upward into the starting position shown in  FIG. 11 .  
         [0103]    
       FIG. 15 
     
         [0104]     The tool is in this case formed by a matrix-capsule-handling head  250 , which comprises a holding plate  255  which is removably connected to the tool holder  1  by means of a permanent magnet, in a manner which is not illustrated. The matrix-capsule-handling head  250  is detached from the tool holder  1  by means of the electromagnet which is arranged in the tool holder  1  and the power supply line  8  of which can be seen. Two rods  252 ,  253 , which are fixedly connected to the holding plate  255 , extend upward in the z direction, i.e. vertically, from two diagonally opposite corner regions of the holding plate  255 . A release plate  254 , which can be displaced in the z direction and is guided by the rods  252 ,  253  in two diagonally opposite corner regions, is arranged above the holding plate  255 . A trigger plate  251  located above the release plate  254  can likewise be displaced in the z direction and is guided by the two rods  252 ,  253 . The vertical displacement of the release plate  254  and of the trigger plate  251  is effected by two motors (not shown), although in principle it could also be brought about manually.  
         [0105]     Sixteen capsule-handling elements  256  are secured in the holding plate  255 . The capsule-handling elements  256 , which are only diagrammatically depicted in this figure, apart from the connecting part  241  and the permanent magnet  240 , are constructed in substantially the same way as the capsule-handling heads  220  shown in  FIG. 11  to  14  and each comprise, in addition to a cylindrical housing  221 , an outer push-button  229  and an inner push-button  236 . The inner push-buttons  236  with the hollow needles attached to them can be actuated jointly as a result of the trigger plate  251  being lowered. The joint actuation of the outer pushbuttons  229  is effected as a result of the release plate  254  being lowered. The matrix-capsule-handling head  250  can be used to take hold of sixteen capsules  150  arranged in a matrix  149  together, to open each of them by means of a hollow needle  235  and if appropriate to mix the substances contained therein with other substances and release them again.  
         [0106]    
       16 
     
         [0107]     The tool is in this case a first exemplary embodiment of a capsule-dispensing head  280 , which comprises a permanent magnet  295 , by means of which, as has been described in a corresponding way in connection with  FIG. 2 , it is connected to the tool holder  1 . The removal of the capsule-dispensing head  280  from the tool holder  1  is effected by means of the electromagnet arranged in the tool holder  1 .  
         [0108]     The capsule-dispensing head  280  comprises a substantially cylindrical housing  281 , the lower part of which narrows to form a neck  282  and in which a large number of capsules  150 , which each contain a substance  151 , are stored. One of the capsules  150  is held by an air-filled sleeve  283 , which is arranged in the neck  282  and is made, for example, from rubber. In a separate cylinder  284  there is a plunger  285 , to which a plunger rod  286 , which projects out through an end wall  287  of the cylinder  284  and is provided at its top end with a push-button  288 , is attached. Between the plunger  285  and the cylinder  284  and between the plunger rod  286  and the end wall  287  there is in each case an annular seal  289 ,  290 . Between the plunger  285  and the base  291  of the cylinder  284  there is a coil spring  292 , which in the stress-free state holds the plunger  285  in the position illustrated. Between the plunger  285  and the end wall  287  there is an air-filled space  293 , which is in communication with the interior of the sleeve  283  via an air line  294 .  
         [0109]     In order for the capsule  150  which is being held by the sleeve  283  to be released, the push-button  288  is pressed downward. In the process, the plunger rod  286  and the plunger  285  are moved downward so as to compress the coil spring  292 , with the result that the size of the space  293  between the plunger  285  and the end wall  287  is increased greatly and a reduced pressure is generated therein. This reduced pressure causes air to be extracted from the interior of the sleeve  283  via the air line  294 , with the result that the internal diameter of the sleeve  283  is increased to a value which is greater than the external diameter of the capsule  150 , so that the capsule  150  is no longer held by the sleeve  283  and drops downward under the force of gravity. At the same time, a second capsule  150  moves up to take the place of the first capsule  150 , it being important for the pressure on the pushbutton  288  to be released again sufficiently quickly, so that the coil spring  292  moves the plunger  285  back upward into the starting position, the size of the space  293  is reduced again and air is fed back to the sleeve  283  via the air line  294  sufficiently quickly for the capsule  150  to be gripped by the sleeve  283 .  
         [0110]     Moreover, the figure diagrammatically indicates that the push-button  288  can be actuated by a rotary lever  297 , the rotary lever  297  being articulatedly mounted on a rod  296  in such a manner that it can rotate in the direction of the arrow, this rod being secured to the permanent magnet  295 . The drive of the rotary lever  297 , which is controlled by the control computer, is not illustrated.  
         [0111]    
       FIG. 17 
     
         [0112]     The tool is in this case a second exemplary embodiment of a capsule-dispensing head  300 , which comprises a permanent magnet  317 , by means of which, as has been described in a corresponding way in connection with  FIG. 2 , it is connected to the tool holder  1 . The removal of the capsule-dispensing head  300  from the tool holder  1  is effected by means of the electromagnet arranged in the tool holder  1 .  
         [0113]     The capsule-dispensing head  300  comprises a substantially cylindrical housing  301 , which in its lower part narrows to form a neck  302  and in which a multiplicity of capsules  150 , which each contain a substance  151 , are stored. One of the capsules  150  is held by an air-filled sleeve  303 , which is arranged in the neck  302  and is made, for example, from rubber, while the other capsules  150  are arranged in the cylindrical housing  301  in a chamber part  315  which can rotate in the manner of a revolver as indicated by arrow E. In a separate cylinder  304  there is a plunger  305 , to which a plunger rod  306 , which projects out through an end wall  307  of the cylinder  304  and is provided at its top end with a push-button  308 , is attached. Between the plunger  305  and the cylinder  304  and between the plunger rod  306  and the end wall  307  there is in each case an annular seal  309 ,  310 . Between the plunger  305  and the base  311  of the cylinder  304  there is a coil spring  312 , which in the stress-free state holds the plunger  305  in the position illustrated. Between the plunger  305  and the end wall  307  there is an air-filled space  313 , which is in communication with the interior of the sleeve  303  via an air line  314 .  
         [0114]     In addition, the capsule-dispensing head  300  comprises a hollow needle  316 , which passes through the pushbutton  308 , the plunger rod  306 , the plunger  305  and the base  311 . As a result of the hollow needle  316  being forced downward, the capsule  150  which is located above the capsule which is held by the sleeve  303  can be punctured. If necessary, another substance, in particular a solvent, can be fed to the open capsule  150  via the hollow needle  316 .  
         [0115]     In order for the capsule  150  which is being held by the sleeve  303  to be released, the push-button  308  is pushed downward. In the process, the plunger rod  306  and the plunger  305  are moved downward so as to compress the coil spring  312 , with the result that the size of the space  313  between the plunger  305  and the end wall  307  is increased greatly and a reduced pressure is generated therein. This reduced pressure causes air to be extracted from the interior of the sleeve  303  via the air line  314 , with the result that the internal diameter of the sleeve  303  is increased to a value which is greater than the external diameter of the capsule  150 , so that the capsule  150  is no longer held by the sleeve  303  and drops downward under the force of gravity. At the same time, the capsule located above this capsule  150  drops into the position which was occupied by the capsule  150  which has been released, it being important for the pressure on the push-button  308  to be released again sufficiently quickly, so that the coil spring  312  moves the plunger  305  back upward into the starting position, the size of the space  313  is reduced again and air is fed back to the sleeve  303  via the air line  314  sufficiently quickly for the next capsule  150  to be gripped by the sleeve  303 . Then, the chamber part  315  is rotated one step onward, so that a new capsule  150  moves into the position directly above the neck  302 . The rotation of the chamber part  315  may be effected externally, for example by hand, or may be triggered by the actuation of the push-button  308 . For this purpose, if necessary, the cylindrical housing  301  has access openings.  
         [0116]     Moreover, the figure diagrammatically indicates that the hollow needle  316  can be actuated by a rotary lever  319  and the push-button  308  can be actuated by a rotary lever  318 , the two rotary levers  319 ,  318  being articulatedly mounted on a rod  321 , which is secured to the permanent magnet  317 , in such a manner that they can rotate in the direction indicated by the arrows. The drives of the two rotary levers  319 ,  318 , which are controlled by the control computer, are not shown.  
         [0117]     A cuboidal housing, in which the capsules  150  are arranged in a plate which can be moved in the x direction and in the y direction, may also be provided instead of the cylindrical housing  301  and the chamber part  315  which can rotate in the manner of a revolver.  
         [0118]      FIG. 18  and  19   
         [0119]     The tool is in this case formed by a screw metering head  320 , which comprises a permanent magnet  321 , by means of which, as has been described in a corresponding way in connection with  FIG. 2 , it is connected to the tool holder  1 . The removal of the screw metering head  320  from the tool holder  1  is effected by means of the electromagnet arranged in the tool holder  1 .  
         [0120]     A motor part  326  is attached to the permanent magnet  321  by means of a connecting part  322 , and an open tube  323 , in which a screw  324 , which can rotate forward and backward about the z direction as indicated by arrow F, with screw shaft  325  is mounted, is secured to its bottom end. The screw  324  can be rotated via the screw shaft  325  by a motor arranged in the motor part  326  and is stably anchored in the z direction. Rotation of the screw  324  results in a ram  327  which runs on the screw moving up or down. The lower, open end of the tube  323  can be closed off by means of a diaphragm  328  which is provided with holes  329  and is secured to two pivot arms  330 ,  331  which are mounted pivotably in a suspension  332  on the motor part  326 . In  FIG. 18 , the diaphragm  328  has been removed from the open end of the tube  323  and can be moved into the closed position illustrated in  FIG. 19  by being pivoted in the direction of the arrow.  
         [0121]     To take up substance, the open end of the tube  323  is moved onto the substance with the diaphragm  328  in its pivoted-away position. Rotation of the screw  324  in the direction which moves the ram  327  upward causes substance to be carried upward directly by the screw  324 .  
         [0122]     To dispense substance, the diaphragm  328  is pivoted under the screw  324  to cover the open end of the tube  323 . Then, the screw  324  is rotated in the direction which moves the ram  327  downward, with the result that substance is forced out downward through the holes  329  in the diaphragm  328  on the one hand directly by the screw  324  and on the other hand by means of the ram  327 .  
         [0123]     The diaphragm  328  is responsible for continuous delivery of substance, but in principle metering is also possible without a diaphragm  328 .  
         [0124]    
       FIG. 20 
     
         [0125]     The tool is in this case formed by a solids-metering head  350 , which comprises a permanent magnet  351 , by means of which, as has been described correspondingly in connection with  FIG. 2 , it is connected to the tool holder  1 . The removal of the solids-metering head  350  from the tool holder  1  is effected by means of the electromagnet arranged in the tool holder  1 .  
         [0126]     On the permanent magnet  351  there is a bearing part  352 , on which a carriage  353  is mounted in such a manner that it can move in the z direction. A holding plate  354  has been pushed laterally into the carriage  353  and has attached to it a metering housing  355 , the internal diameter of which decreases in steps toward the bottom and which has an intermediate base  371  with a conical metering opening which tapers upward. The holding plate  354  with the metering housing  355  can be detached from the carriage  353  by means of a horizontal movement involving little force.  
         [0127]     A rotating metering shaft  357 , which drives a stripper  356  and can be displaced in the z direction, runs in the z direction centrally through the metering housing  355  and the conical metering opening in the intermediate base  371 . At the lower end of the metering shaft  357  there is a closure cone  372  which tapers upward and partially or completely closes off the conical metering opening in the intermediate base  371  depending on the z position, substance which flows downward when the metering opening is partially open being fed to the stripper  356 .  
         [0128]     The rotating metering shaft  357  is fixedly connected to a co-rotating bearing part  368 , projects from below into a shaft  359  driven by a motor  360  and is rotated with the shaft  359 . A rotating stripper  358  which is arranged in the upper part of the metering housing  355  runs through the bearing part  368  and likewise projects into the shaft  359  from below. The stripper  358  can move in the z direction in the bearing part  368  and is driven, together with the metering shaft  357 , by the shaft  359 .  
         [0129]     The displacement of the metering shaft  357  in the z direction is brought about by two electromagnets  362  and  363 , which are mounted on the holding plate  354  and bear a cover plate  366  via two support parts  364 ,  365 . The cover plate  366  is connected to the bearing part  368  fixedly in the z direction, a ball bearing  361  enabling the bearing part  368  to rotate on the rotationally fixed cover plate  366 . On activation, the electromagnets  362 ,  363  generate a force in the z direction and raise or lower the cover plate  366  and as a result the bearing part  368  and the metering shaft  357 .  
         [0130]     The motor  360  and the electromagnets  362 ,  363  are controlled by a control part  367 , which is arranged laterally on the bearing part  352  and to which the motor  360  is secured.  
         [0131]     Moreover, a balance  369  with a minimum weighing range from 0 to 2 kg and an accuracy of 0.1 g, which is in contact with the carriage  353  via a pin  370 , is attached to the bearing part  352 . Balances of this type are commercially available, for example from Sartorius AG, 37070 Gottingen, Germany.  
         [0132]     If substance which is stored in the metering housing  355  is dispensed via the conical metering opening in the intermediate base  371 , the weight load applied to the carriage  353  is reduced and the carriage  353  is pulled downward less strongly, a fact which is measured by the balance  369  via the pin  370 .  
         [0133]     A solids-metering head of this type, but without magnet coupling to the tool holder  1  and without balance  369  arranged directly on the solids-metering head, is marketed by Auto Dose SA, CH-1228 Plan-les-Ouates.  
         [0134]     It is possible to execute further design variations on the devices according to the invention which have been described above. Express mention should also be made of the following at this point:  
         [0135]     The other tools, like the solids-metering head  350 , may also be provided with a balance  369 . As an alternative, it is also conceivable for the balance to be attached to the tool holder  1 .  
         [0136]     The connection between tool holder  1  and tool may also be formed in a different way than with magnets. By way of example, screw connections, bayonet catch connections or clamping connections are conceivable. However, it should be possible for the connection to be produced and released again automatically, i.e. not by hand.  
         [0137]     In addition to the tools described, it is also possible to use further tools which are equipped with a connection point to the tool holder. By way of example, the camera  10  or the infrared-analysis unit could also be designed as independent tools.