METHOD AND APPARATUS FOR CONVEYING A SAMPLE TO A SAMPLE VESSEL

Abstract: The application introduces a method and apparatus for conveying a sample disk into a reaction vessel. According to the invention, the sample disk (11) is attached to a tooth (2), where the sample disk is further conveyed to the reaction vessel.

Description: Method and apparatus for conveying a sample to a sample vessel Background of the invention The present invention relates to laboratory technology and in particular to a method of analysis where in a porous, sheet-like material, such as filter paper, there is absorbed a sample, such as a specimen of dried blood, of which material there is cut a disk, which disk is then conveyed to a vessel or a vessel matrix, such as a set of test tubes or cuvettes, where the sample disk is eluted. After elution, the sample disk can be removed, and the obtained solution is subjected to the analysis in question. In the above described tasks for conveying a sample disk into a reaction vessel and for removing it therefrom, there are generally used a pair of tweezers, and the method requires a lot of manual work. The analyses are usually carried out in series, for instance on a microtitration plate, in which case the analysis is made simultaneously in each well of the plate. The US patent publication 5,474,742 introduces an apparatus whereby sample disks can be simultaneously inserted in and removed from all wells on the plate. The apparatus comprises a framework with arms for each well, and the bottom part of each arm is provided with a shelf-like sample disk retainer. The method and apparatus according to the invention is designed to facilitate and speed up the conveying of samples of the described type in and out of the vessel of analysis. Description of the invention We have now invented a method and apparatus according to the independent claims. Other claims represent a few preferred embodiments of the invention. According to the invention, a sample disk is attached to a tooth, where it is conveyed to the reaction vessel. The sample disk can also be removed from the vessel by the tooth. One rack may contain several teeth, corresponding to the pitch of the cuvettes provided in the plate used in the analysis, which further facilitates the task of perforrning several analyses in series. A tooth may include a sharp, cutting part, in which case the tooth penetrates the sheet with as little damage as possible. Moreover, the tooth may include barbs in order to improve the grip. A sample disk can be cut of a larger sheet, for instance by punching it directly onto the tooth. In this fashion, less steps are needed in the process. The punching is advantageously carried out by pushing the punching tool downwardly, against the sample sheet. The apparatus may include means for shifting the tooth rack, preferably automatically, for the length of a tooth interval at a time. The apparatus may also include means for ensuring an accurate position for the shifted rack. In order to shift the rack, it may contain a suitable grip member, such as an indentation. A combined sample disk punching and fastening can be realized by means of separate actuators, or by means of one and the same actuator. A preferred embodiment of the present invention is explained in more detail below. The accompanying drawings form part of the description. In the drawings figure la illustrates a tooth rack according to the invention, seen from the side to the teeth of which rack the sample disks are attached, figure lb illustrates the tooth rack of figure la from the end, figure lc illustrates one tooth of the rack of figure la from the top, figure 2 illustrates the different stages of attaching the sample disk to the tooth, figure 3 illustrates a tooth rack installed in a set of cuvettes, figure 4 illustrates an apparatus according to the invention, provided with separate actuators for attaching the sample disk and for moving the tooth rack, figure 5a illustrates from the side an apparatus according to the invention, provided with only one actuator both for attaching the sample disk and for moving the tooth rack, and figure 5b illustrates the apparatus of figure 5a from the end. Figures la to lc illustrate a comb-like straight strip 1, provided with vertical teeth 2 spaced according to the pitch of the test tube or cuvette matrix 3 (figure 3). The number of teeth 2 corresponds for example to the number of the wells in a row of the plate, for instance a microtitration plate. Each tooth head is advantageously designed so that it includes a sharp, paper-cutting peak 4, and hooking barbs 5 on opposite sides. In the longitudinal direction of the barbs, the peak of the tooth 2 is somewhat longer than in the transversal direction thereof. The strip 1 can be provided with an indentation 6 or other gripping or slutting member needed for the transfer, as well as with centering means 7 for centering the strip 1 in the cuvette matrix 3. Figure 2 illustrates how in the method according to the invention, a filter paper 8 or other porous plate saturated with a sample is set on top of a punching bed 9, whereafter the user either pulls the lever of a manually operated device, or presses the button or pedal (16) of an automatic device (figure 4, figure 5a), in which case the punching tool 10 cuts out of the paper 8 a sample, most advantageously a round sample 11, shifts it towards the tooth 2, which penetrates the paper 11 simultaneously as the barbs 5 fasten the sample disk 11 onto the tooth 2. Thereafter the punching tool 10 returns to the top position, and the strip 1 can be shifted, either manually or automatically, by means of a grip member such as an indentation 6, forward for the length of an interval according to the pitch of the teeth, as far as the next tooth, and the next cutting step may begin. Figure 3 illustrates how a matrix formed of the teeth 2 of the strip 1 is partly or completely loaded with sample disks 11 and turned upside down to a cuvette matrix 3, in which case the sample disks 11 are submerged in the elution liquid or reagent 12, and the sample of the desired material, such as blood ore serum, is removed from the sample disk. The centering means 7 center the teeth 2 in the cuvette matrix 3. After elution, the strip complete with sample disks 11 can be easily removed. Figure 4 illustrates a preferred embodiment of an automatic punching and conveying device. There an actuator 13, for instance a spindle motor or a pneumatic cylinder, moves a cutting punching tool 10, and another actuator 14, for instance a stepping motor, moves the strip 1 by intermediation of a gear wheel 25. Each actuator can be either electric, such as a magnet, a stepping motor or a spindle motor, or alternatively a pneumatic or a hydraulic cylinder or motor. The cutting and the moving of the strip 1 is synchronized by means of a electronic card or a control unit 15, which is connected to a press button or foot pedal 16 for starting the cutting process. Figures 5 and 5b illustrate a preferred embodiment of an automatic device which is provided with only one motor 13 or other actuator, whereby both the cutting of the paper 8 and the conveying of the strip 1 are performed. For instance a gear motor 13 rotates a cam 17, which fiirther presses the punching tool 10 downwardly by intermediation of a lever 18. The lever 18 is returned to the top position by means of a lever spring 19, and the punching tool 10 is returned by means of a punching tool spring 20. To the lever 18, there is geared a push bar 21, the bottom end whereof moves the bent lever 22 back and forth. The bent lever 22 is attached to shaft 23, and said shaft 23, along with its alternating motion, during the returning motion of the push bar 21 pulls the gear wheel 25 by intermediation of a one-way clutch 24, and the gear wheel further moves the strip 1 by means of the indentation 6 provided therein. Thus the one-way clutch 24 ensures that the gear wheel 25 and the strip 1 only move in one direction. The length of the bent lever 22 and the diameter of the gear wheel 25 are chosen so that the strip 1 moves, during the alternating motion of the lever 18, exactly for the length of the pitch of the teeth 2. A spring-loaded ball 26 is slipped in the notches 27 provided at the side of the strip 1, thus ensuring that the strip 1 is stopped at a point which corresponds to the pitch of the teeth 2. Instead of the lever 18, the apparatus may be provided with a vertical slide. The tooth rack 1 can also be provided with a position sensor, for example a hole at the other end thereof, which ensures that the rack is put in the device in the correct position, and that the order of the sample disks attached in the teeth 2 of the comb is known, as well as the corresponding order of patients.

Claims: Claims 1. A method for conveying a sample disk to a reaction vessel, comprising attaching the sample disk to a tooth and conveying the tooth with the sample disk to the reaction vessel. 2. A method according to claim 1, wherein the sample disk is cut of a larger sheet. 3. A method according to claim 2, wherein the sample disk is attached by cutting it directly onto the tooth. 4. A method according to claim 2 or 3, wherein the sample disk is cut by punching. 5. A method according to any of claims 1 to 4 for conveying a sample disk containing a specimen of blood or serum 6. An apparatus for conveying a sample disk to a reaction vessel, wherein the apparatus comprises a rack (1) provided with a tooth (2) for fastening the sample disk. 7. An apparatus according to claim 6, wherein the rack (1) is provided with a plurality of teeth (2) for fastening sample disks. 8. An apparatus according to 7, wherein the rack is provided with teeth (2) in a row. 9. An apparatus according to claim 8, wherein the teeth (2) are at a constant pitch. 10. An apparatus according to claim 9, wherein the apparatus comprises means (14; 25) for shifting the rack for a length according to the pitch. 11. An apparatus according to claim 10, wherein the apparatus comprises means (14; 25) for sliifting the rack automatically. 12. An apparatus according to any of claims 6 to 11, wherein the tooth has a sharp peak (4). 13. An apparatus according to any of claims 6 to 11, wherein the tooth has a cutting peak (4). 14. An apparatus according to claim 12 or 13, wherein the tooth has barbs (5) for fastening the sample disk. 15. An apparatus according any of claims 6 to 14, wherein the apparatus comprises means (10) for cutting the sample disk of a larger sheet. 16. An apparatus according claim 15, wherein it comprises means (10) for punching the sample disk. 17. An apparatus according to any of claims 6 to 16, wherein the rack (1) comprises grip members (6) in order to convey the rack. 18. An apparatus according to claim 17, wherein the rack (1) comprises an indentation (6) in order to convey the rack. 19. An apparatus according to any of claims 6 to 18, wherein the apparatus comprises one motor (13) for shifting the rack. 20. An apparatus according to claim 19, wherein the apparatus comprises a punching tool (10) working with an alternating motion, so that that from the alternating motion of the punching tool, there is provided lever transmission through a one-way clutch to a gear wheel (25), which moves the comb-like rack (1) forward in a stepping fashion. 21. An apparatus according to any of claims 6 to 20, wherein apparatus comprises means (26; 27) for ensuring an accurate position of the rack (1). 22. An apparatus according to claim 21, wherein the rack comprises notches (27), and a spring-loaded ball (26) is provided order to ensure the accurate position.

Inventors: MIKKONEN JOUKO, TERVAMAEKI JUKKA, TUUNANEN JUKKA, MIKKONEN, JOUKO, TERVAMAEKI, JUKKA, TUUNANEN, JUKKA
Applicants: LABSYSTEMS OY
Application year: 1999
Main classification: G01N1
IPC codes: B01L11, G01N1, G01N35