U.S. patent application number 11/115434 was filed with the patent office on 2005-09-01 for liquid sample pipette with detachable ejector.
This patent application is currently assigned to Gilson, Inc.. Invention is credited to Viot, Francois.
Application Number | 20050191215 11/115434 |
Document ID | / |
Family ID | 8848992 |
Filed Date | 2005-09-01 |
United States Patent
Application |
20050191215 |
Kind Code |
A1 |
Viot, Francois |
September 1, 2005 |
Liquid sample pipette with detachable ejector
Abstract
The sampling pipette comprises a body (2) and an arm movable
relative to the body to eject a cone (9) fixed to the pipette,
ejection taking place in a longitudinal direction (10) of the
pipette, the arm having both a first portion (16, 18, 20) suitable
for coming into contact with the cone, and a second portion (14).
The two portions are engaged one in the other and, starting from an
operating position, they enable the first portion to be separated
from the body (2) by means of an initial movement in a direction
that is essentially perpendicular to the longitudinal direction
(10).
Inventors: |
Viot, Francois;
(Auvers-sur-Oise, FR) |
Correspondence
Address: |
FOLEY & LARDNER
150 EAST GILMAN STREET
P.O. BOX 1497
MADISON
WI
53701-1497
US
|
Assignee: |
Gilson, Inc.
|
Family ID: |
8848992 |
Appl. No.: |
11/115434 |
Filed: |
April 27, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11115434 |
Apr 27, 2005 |
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10240348 |
Mar 24, 2003 |
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10240348 |
Mar 24, 2003 |
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PCT/FR01/01071 |
Apr 9, 2001 |
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Current U.S.
Class: |
422/400 |
Current CPC
Class: |
B01L 3/0279
20130101 |
Class at
Publication: |
422/100 |
International
Class: |
B01L 003/02 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 7, 2000 |
FR |
00/04470 |
Claims
What is claimed is:
1. A sampling pipette comprising: (a) a body; and (b) an ejector
arm attached to the body, the ejector arm comprising an ejector rod
and an actuator connected to the ejector rod, wherein the ejector
rod and the actuator are engaged one in the other such that the
ejector rod and the actuator may be separated by moving the ejector
rod sideways with respect to the actuator.
2. The sampling pipette of claim 1, wherein the ejector rod can be
separated from the actuator without removing the actuator from the
body.
3. The sampling pipette of claim 2, wherein the ejector rod can be
separated from the actuator only when the ejector rod is at the
bottom end of a purge stroke.
4. The sampling pipette of claim 1, wherein the ejector rod and the
actuator can be assembled in only one direction.
5. The sampling pipette of claim 1, wherein the connection between
the actuator and the ejector rod comprises a connection screw.
6. The sampling pipette of claim 5, wherein the ejector rod
comprises a vertical duct for housing the connection screw.
7. The sampling pipette of claim 6, wherein the ejector rod further
comprises a ring capable of slidable engagement with an endpiece of
the body.
8. The sampling pipette of claim 1, wherein the connection between
the ejector rod and the actuator comprises a male-female
connection.
9. The sampling pipette of claim 1, wherein the connection between
the ejector rod and the actuator comprises a bayonet-type
connection.
10. A sampling pipette comprising: (a) a body; (b) an ejector arm
attached to the body, the ejector arm comprising an ejector rod and
an actuator engaged one in the other through a connection, wherein
the connection comprises a sideways facing generally U-shaped
portion and a male portion adapted to be received in a lateral
direction by the generally U-shaped portion.
11. The sampling pipette of claim 10, wherein the generally
U-shaped portion comprises a bottom edge comprising shoulder
forming a step projecting radially from the inside of the
U-shape.
12. The sampling pipette of claim 10, wherein the male portion is
disposed on a T-shaped connection screw.
13. The sampling pipette of claim 12, wherein a support connects
the T-shaped connection screw and the male portion.
14. The sampling pipette of claim 13, wherein the T-shaped
connection screw comprises a core and a threaded rod.
15. The sampling pipette of claim 14, wherein the threaded rod is
screwed into an opening in the ejector rod.
16. The sampling pipette of claim 10, wherein the generally
U-shaped portion comprises limbs that spread apart to accept the
male portion.
17. The sampling pipette of claim 10, wherein the generally
U-shaped portion and the male portion are constructed from
thermoplastic material.
18. A detachable ejector for a liquid sample pipette, the ejector
comprising a connection screw threaded into an ejector rod through
a knurled wheel, wherein the ejector rod is capable of reversible
assembly with a pipette body.
Description
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 10/240,348 filed Mar. 24, 2003, which claims
priority to International Application PCT/FR01/01071, filed Apr. 9,
2001, which claims priority to French Patent Application 00/04470,
filed Apr. 07, 2000. Each of these priority documents, including
the specification, drawings, claims, and abstract, are incorporated
herein by reference in their entirety.
FIELD OF THE INVENTION
[0002] The invention relates to pipettes for taking liquid
samples.
BACKGROUND OF THE INVENTION
[0003] A sampling pipette is known, e.g. from document FR
2,696,110, that is suitable for receiving a discardable cone at its
bottom end, which cone is held on the pipette by means of friction.
The pipette has an ejector that can be actuated by means of a
button adjacent to a sampling button. Pressing on that button
enables the cone to be pushed away from the pipette when it is
desired to replace a used cone with a new cone.
[0004] In that pipette, the ejector has an arm with a bottom
portion for coming into direct contact with the cone, and a top
portion to which the bottom portion is secured by friction
engagement in the longitudinal direction of the pipette. This
engagement enables the bottom portion of the ejector to be
assembled simply and quickly onto the pipette and to be removed
with the same advantages. Nevertheless, while ejecting a cone, at
the moment when the cone gives way and becomes detached from the
tip of the pipette, the ejector follows the cone and its speed
increases suddenly. The movement of the ejector is then stopped
sharply because the top portion comes into abutment against the
body of the pipette. The same braking force is transmitted to the
bottom portion via the friction engagement. Unfortunately, this
force tends to undo the engagement between the bottom and top
portions and to separate them from each other. After ejecting some
number of cones, it can thus happen that the bottom portion of the
ejector becomes separated from the pipette in untimely manner.
[0005] Document WO 96/37302
[0006] has a FIG. 19 providing for an ejector in which the bottom
portion that pushes against the cone is itself engaged in the
longitudinal direction of the pipette in a top portion of the
ejector. A fixing tongue holds together the two interconnected
portions and prevents them from separating in untimely manner.
Nevertheless, in order to remove the bottom portion, it is
necessary to reach the tongue, and that is rather awkward.
[0007] An object of the invention is to provide a pipette of a
different type that avoids untimely separation of the bottom
portion of the ejector, but in which the ejector remains easy to
remove.
SUMMARY OF THE INVENTION
[0008] To achieve this object, the invention provides a sampling
pipette comprising a body and an arm movable relative to the body
to eject a cone fixed to the pipette, ejection taking place in a
longitudinal direction of the pipette, the arm having both a first
portion suitable for coming into contact with the cone, and a
second portion, wherein the two portions are engaged one in the
other and, starting from an operating position, they enable the
first portion to be separated from the body by means of an initial
movement in a direction that is essentially perpendicular to the
longitudinal direction.
[0009] Thus, because the arm still comprises two portions that are
assembled together, it can continue to be removed in simple manner.
Nevertheless, the invention prevents the portions separating in
untimely manner under the effect of forces that arise during
ejection. In addition, since the friction connection is no longer
essential, a connection can be provided that is suitable for being
assembled and disassembled without applying force.
[0010] The invention may also present at least any one of the
following characteristics:
[0011] the pipette is organized in such a manner that the
engagement direction is lateral;
[0012] the pipette is organized in such a manner that there is only
one engagement direction;
[0013] one of the arm portions is T-shaped, suitable for being
received in a correspondingly-shaped housing of the other
portion;
[0014] the pipette is organized in such a manner that the two
portions can be separated from each other without previously
disassembling the pipette;
[0015] the body of the pipette forms an obstacle to separating the
two portions, at least when the arm lies at a high end of the
ejection stroke;
[0016] the pipette is organized in such a manner that the body
enables the two portions to be separated when the arm lies at a low
end of the ejection stroke; and
[0017] the pipette includes adjustment means, enabling the length
of the arm to be varied continuously over a range of values.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Other characteristics and advantages of the invention appear
further from the following description of a preferred embodiment
given by way of non-limiting example. In the accompanying
drawings:
[0019] FIG. 1 is a perspective view of the ejector mechanism of a
pipette constituting a preferred embodiment of the invention;
[0020] FIG. 2 is a fragmentary axial section view of the pipette
showing the location of the FIG. 1 mechanism;
[0021] FIGS. 3 and 4 are two perspective views of the actuator of
the FIG. 1 device;
[0022] FIG. 5 is a fragmentary axial section view on plane V-V of
the FIG. 3 actuator;
[0023] FIG. 5A is an axial section view on plane A-A of the FIG. 5
actuator;
[0024] FIGS. 6 and 7 are a rear view and a left-hand view of the
connection screw of the FIG. 1 mechanism;
[0025] FIGS. 8 and 9 are two cross-section views on planes
VIII-VIII and IX-IX of the FIG. 7 screw;
[0026] FIGS. 10 and 11 are a perspective view and an axial section
view of the ejector rod of the FIG. 1 mechanism;
[0027] FIG. 12 is a plan view of the FIG. 10 ejector 5 rod; and
[0028] FIG. 13 is a diagram showing how the ejector rod is put into
place on the pipette.
DESCRIPTION OF EXEMPLARY EMBODIMENTS
[0029] The sampling pipette constituting the present invention of
the invention is of the same type as that described in document
FR-2,696,110. Reference should therefore be made to that document
for various details of the pipette already disclosed therein. Only
certain aspects of the cone ejector mechanism are described in
detail below.
[0030] With reference to FIG. 2, the pipette conventionally
comprises a body 2 serving as a handle for holding in the user's
hand. The pipette has a piston 6 that is slidably movable along a
longitudinal axis 10 of the pipette in a bottom cavity of the
pipette in order to suck up a volume of liquid that is to be taken
into said cavity, or else to expel it therefrom. Displacement of
the piston is controlled in particular by means of a control rod on
the axis 10 having its bottom portion connected to the piston by
parts of known type. At its top end, the rod is surmounted by a
pushbutton that is rigidly fixed to the rod and that the user can
actuate with the thumb of the hand holding the pipette. The piston
thus moves down and up as a function of the same movement of the
button. The pipette includes a return spring suitable for returning
the piston and the rod to the high position at the end of their
down stroke for expelling liquid, and a purge spring whose effect
is added to that of the preceding spring when the stroke of the
piston is continued downwards for a purge stroke. The pipette has a
bottom tip 7 suitable for receiving a discardable sampling cone 9
in conventional manner, which cone is held by friction acting on
the outside of the bottom tip.
[0031] The pipette has a cone ejector mechanism as shown in FIGS. 1
and 2. This mechanism comprises, going downwards along the
longitudinal direction of the pipette: a control button 12; an
actuator 14; a connection screw 16; a knurled wheel 18; and an
ejector rod 20. The FIG. 1 ejector mechanism extends over the rear
portion of the pipette, i.e. the portion beside the palm of the
user's hand.
[0032] The actuator 14 is generally elongate in shape in a downward
direction and it tapers downwards. It is received in the body 2 of
the pipette so as to be slidably movable therein along the axis 10.
The pipette is arranged in such a manner that downward pressure on
the button 12 causes the actuator 14 to move down. The connection
between the button and the actuator can be of conventional type and
is not described herein. A return spring 19 shown in FIG. 2 serves
to raise the actuator 14 when force is no longer applied to the
button 12.
[0033] With reference to FIGS. 3, 4, 5, and 5A, the actuator 14
presents a bottom end formed by a female coupling portion 22. This
portion is shaped in a direction parallel to the axis 10 and has a
generally U-shaped cross-section, and more precisely a
cross-section in the form of a portion of an ellipse with both
limbs 24 of the U-shape extending towards each other at both ends.
The opening 26 of the U-shape faces sideways, in this case towards
the left-hand side of the pipette. The bottom edge of the coupling
portion 22 has a shoulder forming a step 28 projecting radially
towards the inside of the U-shape. Nevertheless, this shoulder is
also U-shaped. Each limb 24 is separated from the remainder of the
actuator by a horizontal notch 30 extending from a point situated
about halfway along the length of the branch to the free end
thereof. The coupling portion forms a cavity 32 between the limbs
24.
[0034] With reference to FIGS. 6 to 9, the connection screw 16 has
a top head 34. The head 34 includes a support 36 generally in the
form of a rectangular parallelepiped and a male coupling portion 38
suitable for penetrating into the female coupling portion 22 of the
actuator. For this purpose, the male coupling portion 38 is of
constant section parallel to the axis 10, while transversely to
said axis it is generally of elliptical shape. The connection screw
16 has a core 40 from which the support 36 projects upwards, being
offset laterally relative thereto. The height of the male portion
38 is less than the height of the support 36. The top ends of the
male portion 38 and of the support 36 are at the same level, but
the male portion lies at a distance from the core 40 so as to
enable the step 28 to pass between them. The male portion 38
extends towards the right, projecting from the support 36, and also
towards the front and towards the rear. Seen from the left and from
the right it presents a T-shaped profile.
[0035] The male portion 38 is suitable for being received by being
engaged in the female portion 22 in a lateral direction
perpendicular to the axis 10. During insertion, the limbs 24 spread
apart and then move back towards each other, thereby producing a
click indicating that the male portion has reached its reception
position. The limbs are capable of bending because of the notches
30 and because of the material used, which in this case is a
thermoplastic material. The step 28 takes up position between the
male portion 38 and the core 40. The connection screw 16 is thus
rigidly assembled to the actuator 14. This assembly can be
disassembled. Assembly and disassembly are performed by moving the
screw in translation relative to the actuator in a left-right
lateral direction.
[0036] The core 40 of the connection screw has a flat top plate 42
and a thin bottom portion 44 of essentially rectangular section. At
its bottom end it is extended by a threaded rod 46.
[0037] With reference to FIGS. 10 to 12, the ejector rod 20 is
elongate in shape in the vertical direction. Its transverse section
is essentially hollow and open. Nevertheless, this section is
closed at the bottom end 48 of the rod in order to form a ring that
is engaged slidably on a bottom endpiece 50 of the body 2 forming
its bottom end 7, as shown in FIG. 2. The ring is suitable for
coming directly into contact with the cone in order to eject it. In
addition, the rod 20 is essentially non-rectilinear in shape so as
to unite said bottom end 48 lying on the axis 10 of the pipette
with the rear portion of the pipette at the top end of the rod
which is off-center relative to the axis 10.
[0038] At its top end, the rod presents a top vertical duct 52 of
rectangular cross section extending from a top face 54 of the rod
to a notch 56 cut horizontally into the rod from its rear face and
going towards its front face. Beneath the notch, the rod has a
bottom duct 58 coaxial with the top duct 52, but this time of
circular cross section. The diameter of the bottom duct 58 is equal
to the width of the profile of the top duct 52, and likewise the
diameter of the threaded rod 46 of the screw 16 is equal to the
width of the bottom portion 44 of the support.
[0039] The knurled wheel 18 has a central threaded duct to form a
screw-and-nut connection with the rod 46 of the screw 16.
[0040] The wheel 18 is received in the notch 56 in alignment with
the ducts 52 and 58. The screw 16 penetrates into both ducts and
also into the wheel. The male portion 38 projects from the top face
54, with the rectangular portion 44 of the support being received
in the top duct 52, thereby preventing the rod 20 from turning
relative to the screw while allowing them to slide relative to each
other. The wheel 18 forms a screw-and-nut connection with the rod
46 of the screw. The bottom portion of the screw is slidably
received in the bottom duct 58. The rod 20 is thus connected to the
pipette firstly by the connection screw 16 and secondly by the ring
48 engaged on the endpiece.
[0041] The wheel 18 is directly accessible to the user from behind
the pipette through the notch. Turning the wheel causes the rod 20
to slide up or down relative to the body 2 parallel to the axis 10,
thereby adjusting its position as a function of the type of
discardable cone used.
[0042] In order to eject a cone, the button 12 is lowered so as to
bring the rod 20 to the bottom end of its stroke, thereby pushing
the cone downwards and detaching it from the pipette.
[0043] When the ejector mechanism is at rest, i.e. at the top end
of its stroke, the male and females portions 38 and 22 are received
inside the body of the pipette and they are inaccessible to the
user. In addition, they are protected therein against impacts and
against dirt. The rod 20 cannot be removed while in this
position.
[0044] In order to remove the rod 20 and separate it from the
pipette, the button 12 is lowered so as to place the rod in its
bottom end of stroke position. The male and female portions are
then visible. The rod 20 is then pushed sideways to separate the
male and female portions as described above and as shown in FIG.
13. This causes the rod 20 to tilt relative to the body of the
pipette, with such tilting being possible because of clearance at
the ring 48. The bottom portion of the rod is then slid downwards
so as to disengage it from the pipette. Reassembly is performed by
following the same operations in reverse order. The rod 20 can be
assembled and removed without applying force, unlike the
longitudinal connection obtained by friction in the prior art.
[0045] It can thus be seen that the rod 20, the knurled wheel 18,
and the screw 16 constitute a first portion of the ejector arm
suitable for being engaged laterally in the second portion of the
arm as formed by the actuator.
[0046] It should be observed that the rod can also be removed under
such circumstances by turning the wheel until it becomes disengaged
from the connection screw 16. However that would separate the rod
20, the screw 16, and the knurled wheel 18 from one another,
whereas the procedure described above keeps these three parts
connected together.
[0047] Because of the step 28, the rod 20 cannot be separated from
the actuator 14 by sliding parallel to the axis 10. It is necessary
to begin by imparting relative movement in a lateral direction.
There is thus no likelihood of untimely separation occurring while
ejecting a cone.
[0048] The knurled wheel 18 serves to adjust the length of the
ejector arm constituted by the actuator 14 and the rod 20 over a
known range of length values.
[0049] Naturally, numerous modifications could be applied to the
invention without going beyond the ambit thereof.
[0050] For example, the rod 20 could be connected to the actuator
14 by connections of other types that impede relative sliding
between these parts of the ejector, for example one or more
screw-and-nut connections or a bayonet type connection.
[0051] The characteristics enabling the length of the arm to be
adjusted over a known range of values can be implemented
independently of the characteristics relating to the arm being made
up of two portions that are engaged one in the other and that can
be separated in a direction that is perpendicular to the
longitudinal direction.
* * * * *