(Background of the Invention) 1. Field of the Invention This invention relates to the method of reading parameters of exchangeable pipette shafts and a pipette with the system for reading parameters of exchangeable pipette shafts.

2. Description of the Related Art The German patent publication No. 4342178 discloses a pipetting system with a syringe comprising a mounting part, and a syringe piston, and a pipette having in its housing a catcher for a fixing part, and in the sampling part a piston catcher for the syringe piston, a fixing device to fix the mounting part and the syringe piston in catchers, and a piston setting device for sliding the sampling part and the syringe piston in the pipette housing, whereas the syringe comprises an information carrier with information about the syringe and/or its state, and the pipette has a reading device to read information from the information carrier. The syringe collar has a flange with a few axially disposed reading surfaces in one axial position to act as the information carrier. Moreover the pipette has a device to analyse the information read by the reading device, taking into account the setting of the piston setting devices, and an indicator of the dosed quantity of

liquid. The information concerning the syringe and/or its state is read by the pipette reading device when the syringe is mounted in the pipette.

The Polish patent publication No. 151372 discloses an automatic pipette with a microprocessor controller, wherein its shafts comprise coded information concerning their volume in the form of one, two and three stripes contrasting with the shaft colour, while in the controller housing, in a recess therein, an optical or magnetic system for reading this information is located.

Further, the Polish patent publication No. 178640 discloses an automatic pipette, particularly manual repeating pipette for multiple dosing of the same volume of liquid, equipped with a mounting assembly for mounting various exchangeable shafts to take in and dose liquid, each of which comprises a cylinder with a piston axially and slidably positioned therein, whereas exchangeable shafts of various kinds and sizes, when they are mounted to the pipette, assume the same relative piston position inside the cylinder, and are equipped with an element for coding the type of the exchangeable shaft, while the pipette itself is equipped with an assembly for automatic identification of the exchangeable shaft mounted thereto, the assembly being the code reader. The element coding the pipette exchangeable shaft constitutes a coding head connected with the piston, while the pipette assembly for shaft automatic identification is disposed at a location where the coding head is positioned when the exchangeable shaft is mounted to the pipette.

Moreover, the Polish patent application No. P. 341465 discloses a method for electronic read-out of the pipette shaft parameters for a pipette comprising a handle with the electronic system and a display, to bottom part of which shafts are mounted, constructed of a sleeve and a plunger placed therein, controlled by the pipette button. In this known method, while the shaft is mounted to the pipette handle with a turning move, the microswitch disposed in the pipette handle detects shape elements on the shaft upper portion, and the pipette electronic system counts the electric pulses, and when all pulses are counted, an information concerning at least one parameter of the mounted shaft is displayed on the display.

(Summary of the Invention) According to the present invention, in the method of reading parameters of exchangeable pipette shafts in a pipette comprising a handle with a plunger drive assembly and an electronic system for reading and displaying the set volume, whereas to the bottom part of the pipette the shafts constructed of a sleeve and a plunger placed therein are mounted, and the shaft is mountable to the pipette handle by sliding it into the handle with an axial movement, and turning it around the longitudinal axis by a pre- determined angle, where the exchangeable shaft comprising a coding head with at least one coding element on its perimeter bearing information about the parameters of the exchangeable shaft is turned in the handle, the information coded on the coding head is read in the radial direction by at least one sensor positioned in the handle, basing on the read information at least one parameter of the mounted shaft is identified, and on the display of the electronic system the set volume for the identified shaft is displayed.

In the method according to the invention, after identification of the exchangeable shaft on the display of the electronic system the recognised shaft type is displayed, and next the displayed value is either accepted or corrected, and this corrected value is accepted.

In the method according to the invention, the coded information is read in mechanical, electrical, optical, magnetic, inductive, capacitive or acoustic way.

In the method according to the invention, longitudinal groves on the coding head perimeter are employed as coding elements of the coding head, whereas the coded information is read in an optical way.

In the method according to the invention, longitudinal nicks on the coding head perimeter are employed as coding elements of the coding head, whereas the coded information is read in an optical way.

In the method according to the invention, longitudinal stripes on the coding head perimeter, the stripes having different light reflection coefficient, are employed as coding elements of the coding head, whereas the coded information is read in an optical way.

In the method according to the invention, the coding elements are located on the coding head perimeter on one level, and the coded information is read at this one level.

In the method according to the invention, the coding elements are located on the coding head perimeter on few levels, and the coded information is read at these few levels simultaneously.

In the method according to the invention, after the identification of mounting of an exchangeable shaft to the handle, control electric pulses generated by the coding head during turning of the shaft with the coding head around its longitudinal axis are counted within a pre-set time, and after elapsing of this time the frequency of the control electric pulses is decreased to the value sufficient to properly identify the removal of the shaft, while after removal of the shaft from the handle the original frequency of sending electric pulses is restored.

According to the present invention, a pipette with the system of reading parameters of exchangeable pipette shafts comprises a handle with a plunger drive assembly and an electronic system for reading and displaying the set volume, whereas to the bottom part of the pipette an exchangeable shaft is mounted, the shaft constructed of a sleeve and a plunger placed therein, and a coding head connected to the sleeve of the shaft, the coding head comprising at least one coding element bearing on its perimeter the information about the parameters of the mounted shaft, whereas in the handle at least one sensor is disposed to read in the radial direction the information coded on the coding head.

In the pipette according to the invention, the coding element is a longitudinal groove in the coding head.

In the pipette according to the invention, the coding element is a longitudinal nick in the coding head.

In the pipette according to the invention, the coding element has different light reflection coefficient than that of the coding head surface.

In the pipette according to the invention, it comprises many coding elements placed on the perimeter of the coding head on one level.

In the pipette according to the invention, it comprises many coding elements placed on the perimeter of the coding head on few levels.

In the pipette according to the invention, the coding head is a part for mounting the sleeve of the shaft. to the handle.

An advantage of the solution according to the present invention is a fact that the invention enables reading parameters of exchangeable shafts mounted to the pipette handle.

(Brief description of the drawings) The accompanying drawings, which are incorporated in, and form a part of the specification, illustrate the embodiment of the present invention and, together with the description, serve to explain the principle of the invention. In the drawings: Fig. 1 shows the longitudinal section of the pipette with the handle and the exchangeable shaft mounted hereto in its bottom part; Fig. 2 shows the upper portion of the shaft with the coding head; and Fig. 3a to 3e show subsequent stages of identification of the exchangeable shaft in the pipette handle by the electronic system.

(Detailed description of the Invention) Reference will now be made in detail to the preferred embodiment of the invention, an example of which is illustrated in the accompanying drawings.

The pipette shown in Fig. 1 has a handle (1) to bottom portion of which an exchangeable shaft (2) is mounted, constructed of a sleeve (3) and a plunger (4) placed therein, whereas the plunger (4) is controlled by a plunger drive assembly (5) located in the upper portion of the handle (1). Moreover in the handle (1) an electronic system (6) is disposed to read and display the set volume.

Each exchangeable shaft (2) has in the upper portion of the sleeve (3) a coding head (7) with coding elements (8) upon its perimeter in the form of marks, whereas the coding elements (8) bear information about parameters of the exchangeable shaft (2). In turn, in the handle (1) the set of sensors (9) is disposed, connected to the electronic system (6), to read on the direction radial with respect to the pipette axis the information coded on the coding head (7). Preferably the coding head (7) simultaneously constitutes the part for mounting the sleeve (3) of the shaft (2) in the handle (1).

The coding element (8) in the pipette is a longitudinal groove or a longitudinal nick in the coding head (7), but it also may be in the form of a stripe of different light reflection coefficient than the coding head (7) surface. It is obvious that the exchangeable shaft (2) may comprise many coding elements (8) placed on the coding head (7) perimeter on one level, or many coding elements (8) placed on the perimeter of the coding head (7) on few levels.

The method of reading the parameters of exchangeable shafts in the pipette according to the invention is accomplished in the following way. Exchangeable shaft (2) is mounted to the handle (1) by sliding it into the handle (1) with an axial movement, and turning it around its longitudinal axis by a pre-determined angle, whereas while the exchangeable shaft (2) comprising the coding head (7) with coding elements (8) on its perimeter is turned in the handle (1), the information coded on the coding head (7) is read in the direction shown in Fig. 1 by the set of sensors (9) positioned in the handle (1).

Next, basing on the read information, the parameters of the mounted shaft (2) are identified, and the set volume for the identified shaft (2) is displayed on the display of the electronic system (6). Preferably after the identification of the exchangeable shaft (2) on the display of the electronic system (6) the recognised type of shaft (2) is displayed, and

next the displayed value is either accepted or corrected, and the corrected value is accepted.

In the pipette according to the invention, longitudinal groves or nicks, or longitudinal stripes on its perimeter which have different light reflection coefficients are applied as coding elements (8) on the coding head (7), and the coded information is read in optical way. It is obvious that the coded information may also be read in mechanical, electrical, optical, magnetic, inductive, capacitive or acoustic manner.

Detection of placing in or taking out the exchangeable shaft (2) from the handle (1) of the pipette is controlled by the electronic system (6), which generates control electric pulses. Fig. 3a shows a situation when the coding head (7) is not yet inserted to the handle (1). After insertion of the shaft (2) to the handle (1), as it is shown in Fig. 3b, the sensor (9) detects the presence of the shaft (2), while the electronic system (6) counts the control electric pulses in a pre-defined time determined by the interval of opening of its gate, Fig. 3c. Next, after elapsing of this time, the frequency of the electric pulses decreases to value sufficient for proper detection of removal of the shaft (2), and the display of the electronic system (6) displays the value of the set volume, as it is shown in Fig. 3d. When the shaft (2) is removed from the handle (1), Fig. 3e, the electronic system (6) resumes to generate the control electric pulses of the original frequency.