Patent Application
20150050198
The invention relates to a device (pipette) for dosed dispensing of a medium from a container, which comprises a plunger, by depressing the plunger, comprising: a housing; a dispensing mechanism with a dispensing element; an actuating element which can be moved from a first stop to a second stop, wherein the actuating element is coupled to the dispensing mechanism such that, upon movement of the actuating element from the first stop to the second stop, the dispensing element depresses the plunger by a distance; and a setting mechanism for setting the distance travelled by the dispensing element for every movement of the actuating element from the first stop to the second stop, wherein the setting mechanism can be set in steps by rotation of a setting element and has at least a cylindrical wall section.
In laboratory applications, especially, it happens that serial dosing with a predetermined volume (e.g. 1 μl-5 ml) must be performed. The manual dispensing of a plurality of smaller quantities from a syringe without the use of aids is not only difficult, but also error-prone. For this reason, aids, e.g. hand-held dispensers, were developed which make it possible to perform series dosing by presetting the volume to be dispensed. The desired dispensing volume per actuation cycle is pre-set by a setting mechanism.
Prior to dosing, a syringe is inserted into the device and a specific volume of the fluid is drawn up into the syringe. Then, the actuating element is repeatedly actuated until serial dosing has been completed or until the syringe has been emptied.
To reduce the number of auxiliary equipment in the laboratory, most hand-held dispensers are designed so that syringes of various sizes and of different construction can be inserted into the instrument for the purpose of dosing. However, if that increases the versatility of using the device on one hand, the problem arises on the other that it makes it more difficult to set the desired dosing volume, since the plungers of different types of syringes must be depressed by different distances to deliver a specific dosing volume. The desired distance per actuating cycle for a given dosing volume depends in particular on the cross-section of the syringe body.
To find the appropriate setting in each case, guide tables are used that specify the correct setting step of the setting mechanism for various known types of syringes and dispensing volumes per actuation cycle. Even if this approach clearly specifies which step of the setting mechanism is to be selected for a particular type of syringe and dosing volume, there is a significant risk of incorrect settings. For example, it can inadvertently happen that even trained personnel fail to read the correct value from the table, but rather e.g., read a value from an adjacent column on the row. In this way, it can turn out that an entire dosing series is flawed.
Proceeding therefrom, the object of the invention is to provide a device for dosed dispensing of a fluid from a syringe that reduces the susceptibility to errors for the setting of the dosing quantity to be dispensed.
This object is achieved by a device for dosed dispensing of a medium from a container, which comprises a plunger, especially from a syringe, in accordance with claim 1. Advantageous embodiments result from the characteristics of the dependent claims.
The device for dosed dispensing of a medium from a container, which comprises a plunger, by depressing the plunger, comprises: a housing; a dispensing mechanism with a dispensing element; an actuating element which can be moved from a first stop to a second stop, wherein the actuating element is coupled to the dispensing mechanism such that, upon movement of the actuating element from the first stop to the second stop, the dispensing element depresses the plunger by a distance; and a setting mechanism for setting the distance travelled by the dispensing element for every movement of the actuating element from the first stop to the second stop, wherein the setting mechanism can be set in steps by rotation of a setting element and has at least a cylindrical wall section. The device further comprises a display element, having a slot-shaped opening in the housing through which a slot-shaped portion of the cylindrical wall section can be seen from outside the housing; and a tabular list of the respective quantities that are dispensed upon movement of the actuating element from the first stop to the second stop for a predetermined number of different types of syringes at various step-like settings of the setting mechanism, wherein the tabular list is arranged on the cylindrical wall section.
The device is a so-called hand-held dispenser or a pipette for dispensing serial doses, e.g. in the volume range between 1 μl and 5 ml. Through actuation of an actuating element, e.g. a push button, the plunger of the syringe is depressed by a distance corresponding to the desired dosing volume per actuation or actuation cycle. This process is repeated until the syringe is empty or until the serial dosing is complete.
The actuating element is coupled to the dispensing mechanism, which comprises a dispensing element that co-operates directly with the syringe plunger, such that, upon full depression of the actuating element from a first stop to a second stop, the dispensing element is moved precisely by the correct, pre-set plunger stroke.
In order that the correct volume may be set, the inventive device has a setting mechanism. In the context of the invention, the setting mechanism has a setting element by way of which a cylindrical wall section, especially a sleeve and/or setting cylinder, can be adjusted, especially step-wise, and relative to the housing, between different radial settings. This setting determines the translation between the actuator travel of the actuating element and the movement distance of the dispensing element. The dispensing mechanism can moreover have a latch which, after the actuating element has been moved over a certain distance, engages with corresponding counter-toothing of the dispensing element. The actuating element is arranged in an axial direction relative to the setting cylinder; the setting cylinder is arranged so as to be axially immovable relative to the housing. To an extent depending on the angular position of the setting cylinder, the latch coupled to the actuating element is blocked for a distance prior to engagement with the counter-toothing of the dispensing element until the latch is moved along the inner wall of the sleeve. At the lower edge of the sleeve, that is, after a certain distance has been travelled by the actuating element, the latch engages under the action of a force (e.g., generated by an elastic element) with counter-toothing. To an extent depending on the angular position of the setting mechanism and/or the setting cylinder, the latch thus enters sooner or later into engagement with the counter-toothing. Since the counter-toothing is part of the substantially rigid dispensing element, the latch pushes the dispensing element down as far as the stop of the actuating element at the second stop. Then, the actuating element and the latch move under the influence of a restoring force (e.g., a spring) back to the first stop and into the starting position. The latch is configured such that it disengages from the counter-toothing while returning to the first stop, thereby leaving said counter-toothing in its position corresponding to the second stop. The latch thus moves back into its starting position in the setting cylinder. The actuation cycle is now repeated until the serial dosing process complete.
According to the invention, the housing has, relative to the setting cylinder, an axial, slot-shaped recess and/or opening, and/or window. The column of the table arranged in the region of the opening can be seen through this opening from the outside. At different angular positions of the setting cylinder, different columns of the table can be seen, such that the dosing quantity for each type of syringe can be read in a simple manner and with reduced susceptibility to errors.
The columns of the tabular list can each specify the dispensed quantity per actuation of the actuating element for the different types of syringes at the particular setting of the setting mechanism, while the rows can specify the dispensed quantity for a particular type of syringe at the various step-like settings of the setting mechanism.
The slot-shaped opening is especially arranged relative to the cylindrical wall section such that, for a given setting step of the setting mechanism, the appropriate dispensed quantity per actuation of the actuating element can be seen for each type of syringe.
Preferably, information on the various types of syringes and/or information on the properties of the various types of syringes is arranged near the slot-shaped opening at the outer wall of the housing.
The setting mechanism preferably comprises a latch and a counter-toothing, e.g. a rack, wherein, at various settings of the setting mechanism, said latch engages between the stops with the counter-toothing after various movement distances of the actuating element.
The setting mechanism can especially comprise a blocking element, which blocks the engagement of the latch with the counter-toothing until the actuating element is depressed downwards by a certain movement distance, wherein the movement distance depends on the setting of the setting mechanism.
Especially, the housing has a receptacle for attaching a syringe to the housing.
The device can further comprise a locking mechanism for fastening the plunger to the dispensing element.
The device can have a filling element having an actuating slider for filling the syringe. Thus, the plunger can be withdrawn from the syringe body and the syringe thereby filled up before serial dosing begins.
The filling element and the locking mechanism are especially coupled.
Preferably, the device has a restoring mechanism which exerts a (restoring) force on the actuating element in the direction of the first stop.
Further features and advantages of the invention are apparent from the description of preferred an embodiment according to the drawings.
The respective dosing quantities for the different types of syringes for a given setting step are displayed in the remaining rows.
The dosing device 1 also has an actuating button 20 which, from a first stop position (top, as shown in
Furthermore, the dosing device 1 has a setting wheel 30 by way of which the volume to be dispensed in a single dose can be set. By way of a slider 40, which can be moved from a lower position 41 into the illustrated upper position 40, the syringe, which was introduced into a receptacle 14 of the housing 10, can be filled up. The button 42 is provided for the purpose of actuating a locking mechanism with which the plunger or piston of the syringe can be fastened to a corresponding dispensing element.
A central element of the invention is a setting cylinder 31 which is axially fixed relative to the housing. The setting cylinder can be radially rotated or set by way of a setting wheel 30. Quantitative indications of the dispensing volumes for various types of syringe at various settings are arranged in columns on the setting cylinder 31 in the form of a table (the setting step is indicated in the last row).
The cylinder 31 is oriented relative to the window 11 in the housing 10 such that, at a given angular setting of the cylinder 31, the correct dispensing volume can be seen in the window 11 for every type of syringe. To an extent depending on the angular setting of the cylinder 31, the dispensing volumes for a specific type of syringe are displayed in the rows.
The lower edge of the setting cylinder has steps 311, 312, 313, etc., of different axial height. To an extent depending on the angular position at which the cylinder 31 is set, a specific step of the lower edge of the setting cylinder 31 is facing the rack 44. Upon depression of the actuating element 20, a latch, initially at the inner wall of the setting cylinder 31, also moves downwards. To an extent depending on the axial height of the instantaneous setting of the angular position and thus step (e.g., 311, 312, 313, etc.), this latch will now sooner or later engage with the rack 44 and push the dispensing element 4 down into the remaining distance traversed by the actuating element 20 as far as the second stop. Thus, a piston rod coupled to the dispensing element 4 is also pushed downwards by this distance until the desired volume has been dispensed.
Then the actuating element 20 is moved upwards again, as is especially apparent from
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2012 102 292.5 | Mar 2012 | DE | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2013/053835 | 2/26/2013 | WO | 00 |
