Pipette device

Abstract

The present invention provides a pipetting device that can achieve a stable and normal fit without inserting the nozzle cone into the pipette tip more than necessary. [Solution] The nozzle cone 2 is provided with a stopper projection 22a that abuts against the rear end of the pipette tip 4 when the fitting portion 23 is fitted to the pipette tip 4 to its normal fitting length, and a cone-side engaging projection 23a is provided at the tip of the nozzle cone 2 so as to engage with a tip-side engaging recess 41 provided on the inside of the pipette tip 4.

Description

Technical Field

[0001] The present invention relates to a pipette device.

Background Art

[0002] Mainly, as an instrument used for weighing a small amount of liquid (fluid) in a laboratory or a test room, a pipette device in which a pipette tip is detachably provided on a nozzle cone (also referred to as a "chip cone") is used (see Patent Document 1). That is, as shown in FIGS. 5 and 6, this pipette device includes a pipette device main body 100 and an exchangeable pipette tip 400.

[0003] The pipette device main body 100 includes a nozzle cone 200 and an ejector 300. The nozzle cone 200 is inserted until its tip 210 cannot be inserted any further into the rear end of the pipette tip 400 as shown in FIG. 6, and holds the pipette tip 400 in a fitted state.

[0004] The pipette tip 400 fitted to the tip of the nozzle cone 200 as described above is suction-exhausted through the vent hole 220 at the tip of the nozzle cone 200 by operating a push button (not shown) of the pipette device main body 100, so that a desired amount of liquid can be sucked and weighed from the tip of the pipette tip 400 and discharged. When the ejector button (not shown) of the pipette device main body 100 is pressed, the ejector 300 slides in the direction indicated by the arrow in FIG. 6, and as shown by the two-dot chain line in FIG. 6, its tip contacts the rear end of the pipette tip 400, and while maintaining the contact state, the pipette tip 400 can be pressed to be detached from the nozzle cone 200.

Prior Art Documents

Patent Documents

[0005] [Patent Document 1] Japanese Patent Publication No. 2000-107613 [Overview of the project] [Problems that the invention aims to solve]

[0006] By the way, with conventional pipetting devices, it is difficult for the user of the pipetting device to clearly determine whether or not the pipette tip 400 has been properly fitted into the nozzle cone 200. Therefore, users tend to apply more force than necessary to press the nozzle cone 200 into the pipette tip 400. Therefore, excessive force must be applied to the ejector 300 to detach the pipette tip 400, which places a significant burden on the repetitive task of pipetting.

[0007] In view of the above circumstances, the present invention aims to provide a pipette device that can achieve a stable and normal fitting state without inserting the nozzle cone into the pipette tip more than necessary. [Means for solving the problem]

[0008] The pipette device of the present invention comprises a pipette device body having a pipette tip, a nozzle cone having a fitting portion at its tip that fits onto the rear end of the pipette tip, and an ejector that is externally fitted onto the slide cone so as to be axially slidable of the nozzle cone, wherein when the fitting portion of the nozzle cone is fitted onto the rear end of the pipette tip, the ejector slides toward the tip side of the nozzle cone and presses against the rear end of the pipette tip, thereby allowing the pipette tip to be detached, and the nozzle cone is characterized in that it has a stopper projection that abuts against the rear end of the pipette tip when the fitting portion is fitted to the pipette tip to its normal fitting length.

[0009] In the present invention, the stopper protrusions may be provided continuously in the circumferential direction of the nozzle cone, or they may be provided intermittently in a radial pattern.

[0010] The pipette device of the present invention is not particularly limited, but it is preferable that the pipette tip has a tip-side engaging recess or tip-side engaging protrusion on the inner wall surface of the portion into which the fitting portion of the nozzle cone is fitted, and that the nozzle cone has a cone-side engaging protrusion or cone-side engaging recess that engages with the tip-side engaging recess or tip-side engaging protrusion in the normal fitting state. In other words, as the stopper projection is received by the rear end of the pipette tip, the tip-side engaging recess or tip-side engaging projection engages with the cone-side engaging projection or cone-side engaging recess, resulting in a click sensation, which clearly indicates that the nozzle cone has been properly fitted to the pipette tip.

[0011] Furthermore, it is preferable that the pipette tip has a groove-shaped tip-side engagement recess with a substantially arc-shaped cross-section, and that the nozzle cone is formed so that its cross-sectional shape follows the cross-sectional shape of the tip-side engagement recess. In other words, the ring-shaped undercut portion of a conventional pipette tip can be used as the tip-side engagement recess, and only the shape of the nozzle cone of the conventional pipette device needs to be changed, so the pipette device of the present invention can be manufactured without incurring significant costs. [Effects of the Invention]

[0012] The pipette device of the present invention comprises a pipette tip, a nozzle cone having a fitting portion at its tip that fits onto the rear end of the pipette tip, and a pipette device body having an ejector that is externally fitted onto the slide cone so as to be axially slidable of the nozzle cone. The pipette device is configured such that when the fitting portion of the nozzle cone is fitted onto the rear end of the pipette tip, the ejector slides toward the tip of the nozzle cone and presses against the rear end of the pipette tip, thereby allowing the pipette tip to be detached. The nozzle cone is provided with a stopper projection that abuts against the rear end of the pipette tip when the fitting portion is fitted to the pipette tip to its normal fitting length, thereby reducing strain on the wrist during repetitive work and improving work efficiency. [Brief explanation of the drawing]

[0013] [Figure 1] This is a front view showing one embodiment of the pipette device of the present invention. [Figure 2] Figure 1 illustrates the process of attaching a pipette tip to the nozzle cone of the pipette device, with Figure (a) showing the state at the start of attachment, Figure (b) showing the state during attachment, and Figure (c) showing the completed state. [Figure 3] This diagram illustrates the process of removing the pipette tip from the pipetting device shown in Figure 1. [Figure 4] Figure 1 is a semi-cross-sectional view of the tip holder of a pipette device. [Figure 5] This diagram shows the nozzle cone of a conventional pipette device before a pipette tip is attached. [Figure 6] This diagram shows a conventional pipette device with a pipette tip attached to the nozzle cone. [Modes for carrying out the invention]

[0014] The present invention will be described in detail below with reference to the drawings illustrating its embodiments. Figure 1 shows one embodiment of the pipette device of the present invention.

[0015] As shown in FIG. 1, this pipetting device A includes a pipetting device main body 1 and a pipetting tip 4. The pipetting device main body 1 includes a nozzle cone 2, a push button 11, an ejector 3, and an ejector operation part 12.

[0016] As shown in FIG. 4, the nozzle cone 2 has a bottomed cylindrical shape with a head 21, an ejector slide part 22, and a fitting part 23, and a vent hole 24 is formed at the tip. As shown in FIGS. 2 and 3, the ejector slide part 22 is externally fitted with the ejector 3 described later so as to be slidable, and its inner diameter is larger than the inner diameter of the ejector receiving surface 42 provided at the rear end (upper end during use) of the pipetting tip 4 described later and smaller than the outer diameter of the ejector receiving surface 42. The lower end surface thereof is a stopper convex part 22a.

[0017] The fitting part 23 has a substantially frustum shape that once reduces in diameter stepwise from the lower end of the ejector slide part 22 so that the stopper convex part 22a is formed, and then gradually tapers and reduces in diameter toward the lower end, and a ring-shaped cone-side engaging convex part 23a is provided at its lowermost end. The cone-side engaging convex part 23a is provided such that its circumferential surface gradually expands toward the tip of the fitting part 23, and its cross-section has a substantially 1 / 4 circular arc shape that engages with the tip-side engaging concave part △ of the pipetting tip 4 described later.

[0018] Although not shown, the push button 11 is capable of advancing and retreating a piston provided in the pipetting device main body 1 in the direction of the tip of the nozzle cone. By this advancing and retreating, it is possible to suck and discharge liquid to the pipetting tip 4 described later through the vent hole 24. The ejector 3 has a cylindrical shape and is externally fitted to the nozzle cone 2 so as to be slidable in the axial direction of the nozzle cone 2, and its lower end surface has an inner diameter smaller than the outer diameter of the pipetting tip 4.

[0019] As shown in Figure 1, the ejector 3 has an engaging projection 31 at its upper end that engages with an engaging groove 12a at the lower end of the ejector operating section 12, and is designed to descend when the ejector operating section 12 is pushed downward. The pipette tip 4 is made of the same material as conventional products and has an undercut with an arc-shaped cross-section. This undercut is used as a tip-side engagement recess 41, and the rear end is provided with an ejector receiving surface 42.

[0020] The following describes how to use this pipette device A. [Attaching pipette tip 4] As shown in Figure 2(a), the lower end of the nozzle cone is positioned above the pipette tip 4, and then, as shown in Figure 2(b), the pipette device body 1 and the pipette tip 4 are moved relative to each other so that the fitting portion 23 of the nozzle cone fits into the pipette tip 4. Furthermore, as the nozzle cone fitting portion 23 is inserted into the pipette tip 4, the pipette tip 4 undergoes elastic deformation such that its wall surface bends outward due to the cone-side engaging projection 23a. As shown in Figure 2(c), the fitting portion 23 is further inserted into the pipette tip 4 until the stopper projection 22a contacts the ejector receiving surface 42. As the stopper projection 22a contacts the ejector receiving surface 42, the cone-side engaging projection 23a fits into the tip-side engaging recess 41, and the wall surface of the pipette tip 4 returns to its original state due to the elastic restoring force, so that the outer circumferential surface of the cone-side engaging projection 23a is in close contact with the inner wall surface of the tip-side engaging recess 41. Furthermore, when the cone-side engaging projection 23a fits into the tip-side engaging recess 41 due to the elastic restoration described above, a click sensation is transmitted to the user's hand, making it easy to sense that the device has been properly engaged.

[0021] [Removing pipette tip 4] The ejector operating unit 12 is operated to bring the lower end surface of the ejector 3 into contact with the ejector receiving surface 42 of the pipette tip 4, as shown in Figure 3. Then, the ejector 3 is further slid toward the tip of the nozzle cone to detach the pipette tip 4 from the nozzle cone.

[0022] As this pipette device A is configured as described above, it has the following effects and benefits. (1) Since a stop projection 22a is provided, the fitting portion 23 of the nozzle cone will not be inserted into the pipette tip 4 beyond the normal fitting position. (2) As the stopper projection 22a contacts the ejector receiving surface 42, the cone-side engaging projection 23a engages into the tip-side engaging recess 41, so that a click sensation is transmitted to the user's hand, making it easy to feel that the engagement has been completed correctly, and thus improving work efficiency. (3) Since conventional general-purpose products can be used as pipette tips 4, the pipette device body 1 can be manufactured without incurring additional costs by simply changing the nozzle cone portion of the pipette device body 1.

[0023] The present invention is not limited to the embodiments described above. For example, in the above embodiment, only one pipette tip could be attached to the pipette device body, but multiple nozzle cones can be arranged in parallel, and a pipette tip can be attached to the tip of each nozzle cone, allowing for simultaneous aspiration and discharge of liquid to each pipette tip with the operation of a single push button. In the above embodiment, the nozzle cone had a cone-side engaging projection and the pipette tip had an undercut recess which was a tip-side engaging recess. However, it is also acceptable to provide a cone-side engaging recess at the lower end of the fitting portion of the nozzle cone and a tip-side engaging projection on the inner surface of the pipette tip.

[0024] In the above embodiment, as shown in Figure 1, the ejector can be operated by the ejector operating section by engaging the engagement projection of the ejector with the engagement groove of the ejector operating section. However, it is also possible to connect them by other means, and the connecting section may be housed inside the casing of the pipette device body so that it is not visible from the outside. [Explanation of Symbols]

[0025] A Pipette device 1. Pipette device body 11 Push buttons 12 Ejector operating section 12a Engagement groove 2 Nozzle cones 21 Head 22 Ejector slide section 22a Stopper protrusion 23 Fitting part 23a Cone-side engaging projection 24 ventilation holes 3 Ejectors 31 Engagement protrusion 4 pipette tips 41 Chip-side engagement recess 42 Ejector receiving surface

Claims

1. Pipette tips, and, A nozzle cone having a fitting portion at its tip that is fitted to the rear end of this pipette tip, The pipette device body comprises an ejector fitted onto a slide cone so as to be slidable in the axial direction of the nozzle cone, A pipette device in which, with the fitting portion of the nozzle cone fitted to the rear end of the pipette tip, the ejector slides toward the tip of the nozzle cone and presses against the rear end of the pipette tip, thereby enabling the pipette tip to be detached, A pipette device characterized in that the nozzle cone has a stopper projection that abuts against the rear end of the pipette tip when the fitting portion is fitted to the pipette tip to its normal fitting length.

2. The pipette tip has a tip-side engaging recess or tip-side engaging projection on the inner wall surface of the portion into which the nozzle cone fitting portion is fitted. The pipette device according to claim 1, wherein the nozzle cone has a cone-side engaging projection or cone-side engaging recess that engages with the tip-side engaging recess or tip-side engaging projection in the normal fitting state.

3. The pipette tip has a groove-shaped tip-side engagement recess with a substantially arc-shaped cross-section, The pipette device according to claim 2, wherein the nozzle cone is formed such that its cross-sectional shape conforms to the cross-sectional shape of the tip-side engaging recess.

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