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Publication numberUS3815790 A
Publication typeGrant
Publication dateJun 11, 1974
Filing dateSep 18, 1972
Priority dateSep 18, 1972
Also published asDE2456049A1, DE2456049B2, DE2456049C3
Publication numberUS 3815790 A, US 3815790A, US-A-3815790, US3815790 A, US3815790A
InventorsAllen D, Lee T
Original AssigneeKensington Scient Corp
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Precision liquid pipetting devices
US 3815790 A
Abstract
Precision liquid pipetting devices for use with disposable pipettes having improved means for adjusting the stroke of the plunger within the pipette and for precisely calibrating the volumetric capacity.
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Description  (OCR text may contain errors)

United States Patent 1191 Allen et al. 1 June 11, 1974 [5 PREClSlON LIQUID PIPETTING DEVICES 3.343.539 9/1967 Moorehouse 222/309 x 3.3 6,286 l l968 Kl h 222 386 [75] Inventors: Allen Pmole? Thomas 3,4?7904 12/1968 222/386 Lafayette, both of Cahf- 3,606.086 9/1971 Drummond 222/309 x [73] Assignee: Kensington Scientific Corporation,

Emeryville, Calif. Primary Examiner-Robert B. Reeves [22] Flled: Sept 1972 Assistant ExaminerTh0mas E. Kocovsky [211 App]. N0.: 289,996

[52] US. Cl 222/309, 128/218, 222/386 511 1m. (:1. G01f 13/00 [57] ABSTRACT [58] Field of Search 222/308, 309, 386;

73/4254 P, 425,6; 128/218 P, 218 PA, 218 Precision liquid pipetting devices for use with dispos- C, 218 D, 218 F, 234 able pipettes having improved means for adjusting the stroke of the plunger within the pipette and for pre- [56] References Cited cisely calibrating the volumetric capacity.

UNITED STATES PATENTS 3.334,?88 8/1967 Hamilton 222/386 X 7 Claims, 8 Drawing Figures PRECISION LIQUID PIPETTING DEVICES This invention relates generally to precision liquid pipetting devices and more particularly to improved means for adjusting the stroke of and calibrating the capacity of pipetting dispensers.

The principal object of this invention is to provide improved means for calibrating the volumetric capacity of a pipetting dispenser with a reproducible high degree of accuracy.

Another object of this invention is to provide simple means for selectively varying the volume of liquid dispensable from a micropipette of a particular size.

Other objects and advantages of the invention will become apparent upon consideration of the following description and the accompanying drawings wherein FIG. I is an overall view of one embodiment of precision pipetting device employing a disposable pipette of relatively large diameter;

FIG. 2 illustrates another embodiment of precision pipetting device which employs a disposable micropipette of much smaller diameter;

FIG. 3 is a cross-sectional view of the barrel and plunger assembly of the pipetting device of FIG. 1;

FIG. 4 is a cross-sectional view of the end of the barrel of the pipetting device of FIG. 3 with a different end cap in place;

FIG. is an end view of the cap ends of the pipetting devices of FIGS. 1 and 2;

FIG. 6 is a cross-sectional view of the calibration assembly of the pipetting device of FIG. 2;

FIG. 7 is a cross-sectional view of an alternate end construction for the pipetting device of FIG. 2; and

FIG. 8 is a cross-sectional view of the calibration assembly of the pipetting device of FIG. 1.

This invention relates to improvements in precision pipetting devices of the type generally disclosed in M. E. Drummond, et al. US. Pat. No. 3,606,086 issued Sept. 20, 1971 for Microdispensing Device. The devices include an elongated barrel 1 and a disposable pipette demountably mounted on the barrel, such as the extruded plastic pipette 2 of relatively large diameter illustrated in FIG. 1 or the smaller precision glass micropipette 2' illustrated in FIG. 2. A reciprocable plunger 3 carried in part within the barrel 1 has one end within the pipette to draw liquid into and to dispense liquid from it.

Each of the described embodiments of barrel 1 has an interior bore into which the plunger 3 passes and is affixed to a plunger holder 4 at one end. The coil spring means 5 within the bore of the barrel seats at one end against the barrel itself and at the other end against a seat 6 on the plunger holder, for example, to bias the plunger toward the withdrawn end of its stroke as is shown in FIGS. 3 and 4.

A series of end caps 7, 7 or more, each thread into the open end of the barrel and each has a bore through which the plunger holder 4 slides. These threaded end caps 7, 7' have a generally circular head 8 substantially larger in diameter than the barrel 1 which is flattened as at face 9 shown in FIG. 5 to prevent roll of the pipetting device when it is resting upon a generally horizontal surface. Each end cap 7, 7 also has a shoulder 10 spaced from its threads toward the coil spring means against which the plunger holder seat 6 abuts as the spring means biases the plunger toward the withdrawn end of its stroke. As will be noted by a comparison of FIGS. 3 and 4 the shoulder 10 of each of the series of end caps 7, 7', etc. is spaced a different difference from its threads so that by interchanging end caps one can selectively adjust the length of the plunger stroke in predetermined increments. A button head 11 threads into the remote end of the plunger holder 4 for manipulation of it. The thumb or forefinger of the user presses upon this button head and simultaneously pulls against the head 8 of end cap 7, 7'. etc. to extend the plunger 3. The bias coil spring means 5 returns the plunger 3 to the withdrawn end of its stroke.

The embodiment of dispenser illustrated in FIG. 1 includes a plunger 3 which carries at its free end a semiresilient tip 15 which is substantially larger in diameter than the plunger and flexibly embraces the interior walls of the pipette 2 to force fluid from or draw fluid into the pipette. A similar construction is shown in FIG. 6 in the tip 15' of the other embodiment of the invention. The precision micropipette 2 can be formed with an internal diameter so precise that for small diameters the plunger 3 may be deployed within it without any tip 15' as is shown in FIG. 7.

The device of FIG. 1 has a pipette stop 20 mounted adjacent to the pipette-end of the barrel which is adjustably positionable along the axis of travel of the plunger. In that embodiment the pipette stop 20 as shown in FIG. 8 comprises a hub 21 with an interior bore 22 which slides upon a cylindrical tip 23 of substantially the same diameter which protrudes from that end of the barrel 1 and sleeves over reciprocable plunger 3. Set screw 24 in the hub 21 of the pipette stop 20 can be tightened against cylindrical tip 23 to position the stop 20 at any point along it. A smaller diameter sleeve portion 25 of the stop 20 carries the flanged end of plastic pipette 2 press fit upon it with its flange 26 seated against hub 21. By precisely positioning stop 20 on the protruding cylindrical tip 22 of the barrel, one can precisely calibrate the volume of the pipette into which liquid is drawn and from which it is dispensed for any particular plunger stroke.

The structure of the dispenser embodiment of FIG. 2 is similar in function. As is illustrated more particularly in FIG. 6 the pipette stop 20 has a bore for the plunger 3 which is smaller than the diameter of the pipette 2' that mounts at the end of the barrel. The stop 20', too, is adjustably positionable along the axis of travel of the plunger 3 by shifting its position within a cylindrical bore 28 in the end of barrel 1 and by holding it there with set screw 24'. The pipette 2 seats against the pipette stop 20 and is held against it by a knurled collet 30 having female threads which thread upon a male threaded portion 31 of the barrel 1. A conical seat 32 within the threaded portion 31 of the barrel and next to bore 28 diverges outwardly toward the collet. A semi-resilient truncated generally conical pipette retainer 33 encompasses the pipette and is forced against the conical seat 32 as the collet 30 threads upon the threaded portion 31 of the barrel.

The precision pipetting dispensers of this invention provide the user with a means for precisely measuring and dispensing volumes in the order from I to I00 lambda or larger. They also provide a given dispenser with a variety of stroke lengths by an appropriate series of interchangeable end caps 7, 7', etc. Accuracy and reproducibility in the order of :1 percent is easily attained. The dispenser is easily calibrated by placing in either of pipettes 2 or 2' a calibration tool which is nothing more than a wire or rod of predetermined length, loosening the set screws 24, 24 and in the embodiment of FIG. 2 loosening collet 30 also. With the calibration tool of known length slipped into the open end of the pipette, the pipette is placed vertically with that end against a flat horizontal surface so that the end of the tool aligns precisely with the end of the pipette. This automatically positions the loosened pipette stop for correct calibration for that particular calibration tool. The set screw 24, 24 is then tightened in this position and, in the embodiment of FIG. 2, the collet is tightened to hold the pipette against the stop The press fit of pipette 2 upon sleeve portion of the stop 20 in the embodiment of FIGJI holds that pipette in place against hub 21 of the stop The two embodiments of this invention have been described for illustrative purposes only. The invention is defined in the following claims.

We claim:

1. In a precision liquid pipetting device having an elongated barrel,

a pipette mounted upon one end of the barrel, and

a plunger carried in part within the barrel and reciprocable with a predetermined stroke within the pipette to draw liquid into and to dispense liquid from the pipette,

the improvement comprising a pipette calibration stop mounted adjacent said end of the barrel and being adjustably positionable along the axis of travel of the plunger, such that the pipette can be adjustably positioned with respect to the stroke of said plunger, and

means holding the pipette against the pipette stop.

2. The precision liquid pipetting device of claim 1 wherein the improvement further comprises a semiresilient tip on the end of the plunger flexibly embracing the interior walls of the pipette.

3. The precision liquid pipetting device of claim 1 wherein the means holding the pipette against the pipette stop is a cylindrical sleeve integral with the stop upon which the pipette press fits.

4. The precision liquid pipetting device of claim 1 wherein the means holding the pipette against the pipette stop is a collet threaded to said end of the barrel.

5. The precision liquid pipetting device of claim 4 wherein the improvement further comprises a semi-resilient truncated conical pipette retainer encompassing the pipette;

a male threaded portion on said end of the barrel and a conical seat within the threaded portion that diverges toward said end; and

corresponding female threads on the collet for forcing the retainer against the seat when threaded upon the male threads to retain the pipette against the pipette stop.

6. In a precision liquid pipetting device having an elongated barrel,

a pipette mounted upon one end of the barrel.

a plunger carried in part within the barrel and reciprocable with a predetermined stroke within the pipette to draw liquid into and to dispense liquid from the pipette, and

coil spring means within the barrel for normally biasing the plunger to a withdrawn end of its stroke, the improvement comprising a pipette calibration stop mounted adjacent said end of the barrel and being adjustably positionable along the axis of travel of the plunger such that the pipette can be adjustably positioned with respect to the stroke of said plunger;

means holding the pipette against the pipette stop;

and

one of a series of end caps threaded to the barrel at its other end, each of the series having a shoulder spaced a different distance toward the spring means and by abuttment selectively limiting the travel of the plunger at the withdrawn end of its stroke.

7. The precision liquid pipetting device of claim 6 wherein the end cap is generally circular with a diameter greater than the barrel and has a flattened face for preventing roll of the pipetting device when resting upon a generally horizontal surface.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US3334788 *Aug 13, 1963Aug 8, 1967Hamilton Clark HSyringe for chromatographic analyses
US3343539 *Oct 22, 1964Sep 26, 1967Moorhouse Turkey Hatchery IncPiston type artificial insemination syringe having stroke adjusting means
US3366286 *Oct 23, 1965Jan 30, 1968Garth A. KloehnHigh precision syringe
US3417904 *Jan 11, 1966Dec 24, 1968Fischer & Porter CoSyringe and method of making same
US3606086 *Nov 10, 1969Sep 20, 1971Drummond Instr CoMicrodispensing device
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3921864 *Sep 20, 1973Nov 25, 1975Dawes Ernest FrederickSyringes for making precision volume measurements
US4020698 *Oct 28, 1975May 3, 1977Marteau D Autry EricPipette which may be calibrated
US4084730 *Sep 15, 1976Apr 18, 1978Labora Mannheim Gmbh Fur LabortechnikMeasuring and pipetting device
US4098125 *Mar 30, 1977Jul 4, 1978Lee Thomas EAdjustable volume pipetting device
US4140488 *Sep 6, 1977Feb 20, 1979Hycel, Inc.Sample liquid transfer means in an automatic chemical testing apparatus
US4141469 *May 2, 1977Feb 27, 1979Lee Thomas EMicrodispensing dilution system
US4154108 *Mar 13, 1978May 15, 1979Labora Mannheim GmbhHand pipette
US4165646 *Jul 26, 1978Aug 28, 1979Shapiro Justin JAdjustable micro-dispensing liquid pipet
US4178803 *May 11, 1978Dec 18, 1979Lee Thomas EPipetting devices
US4249419 *Jan 5, 1979Feb 10, 1981Thomas Bradley SMicropipette system
US4442722 *Jan 7, 1983Apr 17, 1984Beckman Instruments Inc.Plunger operated pipet
US4679446 *Sep 9, 1985Jul 14, 1987Baxter Travenol Laboratories, Inc.Multi-volume displacement pipette
US5725831 *Mar 24, 1995Mar 10, 1998Becton Dickinson And CompanyNucleic acid amplification apparatus
US6547432 *Oct 17, 2001Apr 15, 2003Stryker InstrumentsBone cement mixing and delivery device for injection and method thereof
US6702990 *Feb 5, 2002Mar 9, 2004The Gel CompanySpot picker
US7393342Aug 13, 2007Jul 1, 2008Stryker CorporationBone cement mixing and delivery system including a delivery gun and a cartridge having a piston, the delivery gun configured to release the piston
US7677418Jun 13, 2008Mar 16, 2010Stryker CorporationBone cement cartridge with a releasably locked drive piston, the piston configured to be unlocked by a delivery device
US8061887Feb 12, 2010Nov 22, 2011Stryker CorporationCartridge in which bone cement is mixed and from which bone cement is delivered, the cartridge having a compressible blade with plural vanes
US8353622Nov 11, 2011Jan 15, 2013Stryker CorporationCartridge from which bone cement is discharged, the cartridge having a removably coupled nozzle
US8721600Nov 30, 2012May 13, 2014Stryker CorporationDelivery gun for dispensing bone bement from a cartridge, the gun having a multi-link linkage and capable of dispensing the cement at different flow rates
US8758705 *Aug 30, 2011Jun 24, 2014Medicatec Kabushiki-KaishaDispenser
US8833576 *Jul 4, 2011Sep 16, 2014Lameplast S.P.A.Re-closable container for fluid products, particularly for medical, pharmaceutical and cosmetic products
US20120255378 *Aug 30, 2011Oct 11, 2012Medicatec Kabushiki-KaishaDispenser
US20130098864 *Jul 4, 2011Apr 25, 2013Lameplast S.P.A.Re-closable container for fluid products, particularly for medical, pharmaceutical and cosmetic products
DE2633530A1 *Jul 26, 1976Feb 3, 1977Pasteur InstitutVorrichtung zur aufnahme und/oder abgabe kleiner dosierter fluessigkeitsmengen
DE2759305C3 *Feb 10, 1977Sep 3, 1981Thomas E. Lafayette Calif. Us LeeTitle not available
EP0076406A2 *Sep 17, 1982Apr 13, 1983Miles Laboratories, Inc.Analytical device and method
WO1993011870A1 *Dec 11, 1992Jun 24, 1993Poulten Ltd JohnPipetter
Classifications
U.S. Classification73/864.13, 222/309, 222/386, 73/864.14, 422/925, 604/208
International ClassificationG01F11/06, G01F11/02, B01L3/02
Cooperative ClassificationB01L3/0224, G01F11/06
European ClassificationG01F11/06, B01L3/02C3D
Legal Events
DateCodeEventDescription
Jan 30, 1990ASAssignment
Owner name: BAXTER INTERNATIONAL INC.
Free format text: CHANGE OF NAME;ASSIGNOR:BAXTER TRAVENOL LABORATORIES, INC., A CORP. OF DE;REEL/FRAME:005050/0870
Effective date: 19880518
Mar 2, 1987AS03Merger
Owner name: AMERICAN HOSPITAL SUPPLY CORPORATION INTO
Effective date: 19870126
Owner name: BAXTER TRAVENOL LABORATORIES, INC. A CORP. OF DE
Mar 2, 1987ASAssignment
Owner name: BAXTER TRAVENOL LABORATORIES, INC. A CORP. OF DE
Free format text: MERGER;ASSIGNOR:AMERICAN HOSPITAL SUPPLY CORPORATION INTO;REEL/FRAME:004760/0345
Effective date: 19870126
Jun 27, 1984ASAssignment
Owner name: AMERICAN HOSPITAL SUPPLY CORPORATION,
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST. EFFECTIVE DATE JULY 3,1983;ASSIGNOR:SMI ACQISITION CORPORATION;REEL/FRAME:004277/0228
Effective date: 19840622
Jun 27, 1984AS02Assignment of assignor's interest
Owner name: AMERICAN HOSPITAL SUPPLY CORPORATION,
Effective date: 19840622
Owner name: SMI ACQISITION CORPORATION
Jul 7, 1983AS02Assignment of assignor's interest
Owner name: SCIENTIFIC MANUFACTURING INDUSTRIES,
Effective date: 19830701
Owner name: SMI ACQUISITION CORPORATION, A DE CORP.
Jul 7, 1983ASAssignment
Owner name: SMI ACQUISITION CORPORATION, A DE CORP.
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:SCIENTIFIC MANUFACTURING INDUSTRIES,;REEL/FRAME:004149/0597
Effective date: 19830701