Search Images Maps Play YouTube News Gmail Drive More »
Sign in
Screen reader users: click this link for accessible mode. Accessible mode has the same essential features but works better with your reader.

Patents

  1. Advanced Patent Search
Publication numberUS3646817 A
Publication typeGrant
Publication dateMar 7, 1972
Filing dateSep 30, 1969
Priority dateMar 21, 1952
Also published asCA946337A1, CA954836A1, CA958383A1, CA966096A1, CA976929A1, CA1025821A1, DE1598123A1, DE1598123B2, DE1598124A1, DE1598124B2, DE1916515A1, DE1917491A1, DE1917491B2, DE1927773A1, DE1927773B2, DE1927773C3, DE1952774A1, DE1952774B2, DE1955807A1, DE2227731A1, DE2227731B2, DE2227731C3, DE2245413A1, DE2245413B2, DE2245413C3, DE2248573A1, DE2248573B2, DE2324681A1, DE2324681C2, DE2505431A1, DE6943120U, DE7236386U, US2724275, US3244009, US3494201, US3506164, US3525264, US3741732, US3757585, US3766784, US3766785, US3853012, USRE27637
Publication numberUS 3646817 A, US 3646817A, US-A-3646817, US3646817 A, US3646817A
InventorsGerald V Hinchman, William D Schmitz, James L Sommerville
Original AssigneeBio Dynamics Inc
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Pipette
US 3646817 A
Abstract
A pipette pump having two pistons therein with a smaller one of said pistons telescoped and movable within a larger of said pistons. The pistons are normally held in projected position by a pair of springs one of which is much stronger than the other so that the larger piston against which it acts is depressed after the smaller piston. The travel of each piston is adjustable and the pistons are both depressed by depressing a cap which is fixed to the smaller piston.
Images(2)
Previous page
Next page
Claims  available in
Description  (OCR text may contain errors)

United States Patent [151 3,646,817 Hinchlman et al. 1 Mar. 7, 1972 PIPETTE 2,660,342 11/1953 Ruf ..73/425.6 X 3 045 494 7/ l962 Gerarde... ..73/425.6 72 l t Gerald V. lllnch m L. Somme l 1 vine; wflum 'f'fi f a" of 3,494,201 2/1970 Roach ....73/425.6 anapousy [m1 3,500,689 3/ 1970 Band ..73/425.4 [73] Assignee: lilo-Dynamics, lnc., lndianapolis, lnd. primary Examiner muis Prince 22 Filed; Sept 30 9 9 Assistant Examiner-William A. Henry, ll pp o 8 Attorney-Woodard, Weikart, Emhardt and Naughton Related u.s. Application Data [571 ABSTRACT [63] continuatiomimpan of Sen No. 770,663, Oct. 25 A pipette pump having two pistons therein with a smaller one 1968 abandone of said pistons telescoped and movable within a larger of said pistons. The pistons are normally held in projected position by [52] [1.5. CI ..73/425.6 a P of springs one of which is much stronger than the other 51 Int 3 U Go 1 14, 301 1 3 /02 so that the larger piston against which it acts is depressed afler [58] Field of Search .11 ..I:.....73/425.6; T the smaller piston. The travel of each piston is adjustable and 141/24-27; 128/233, 223 the pistons are both depressed by depressing a cap which is fixed to the smaller piston. 56 References Cited W UNITED STATES PATENTS I 1,747,523 2/l930 McCormick ..73/425.6 m Drawing Figures 76 57 55 5 5 J6 /z 4/ a2 0 i I i l /7 /v 4 9| T 5? rm 22 j a L \/y\ /l l/ 1 1/ 2/ /4 46 47 62 40 .37 4 2 5/ /6 PATENTEDHAR 7 I972 SHEET 1 UF 2 M Rh J km. y nun R Q INVENTORS GERALD V. Hmcwmm JAMES L. SOMMERVILLE WILLIAM D. Scnmwz MW MM M $220 ATTOZ/VEVS PATENTEDHAR 7 I972 MIMI/ll)!!! Fig. 3.

Fig.7.

INVENTORS Guano V. HmcuMAu JAMES L. SOMMEQV\LLE Wmnmv. D. Scum-r2 BY wmMmmgwmvwm ATTORNEYS llO Fig.6.

CROSS-REFERENCES TO RELATED APPLICATIONS This application is a continuation-in-part of application Ser. No. 770,663, filed Oct. 25, 1968 now abandoned.

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a pipette pump.

2. Description of the Prior Art Various types of pipettes are used for medical testing and the like. For many years glass pipettes have been known and available. Such pipettes are emptied by the use of the finger or the mouth. In more recent years plastic pipettes of predetermined volume capacity have come into widespread use. The latter type of pipette in many cases is more convenient to use than the former and also is disposable. It is desirable, however, to provide a pipette which is less expensive, more accurate and more convenient to use. A representative grouping of prior art might include: US. Pat. Nos. 2,902,035 to Hartley; 3,062,056 to Wicoff; and 3,290,946 to Pursell.

SUMMARY OF THE INVENTION The present invention is an improved pipette pump for use with disposable pipettes. It may include a housing having a chamber therein, said chamber having an opening communicating with atmosphere and through which air is expelled for pumping, a piston reciprocably mounted on said housing for movement into and out of said chamber, and an O-ring sealingly mounted on said housing, said piston being slidable through said O-ring and sealing against said O-ring.

One object of the invention is to provide an improved pipette pump.

A further object of the invention is to provide an improved pipette.

Another object of the invention is to provide a pipette which is less expensive, more accurate and more convenient to use than existing pipette pumps and to provide a pipette which is easy to adjust with regard to liquid dispensed.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a section taken axially and longitudinally of the pipette pump of the present invention;

FIG. 2 is an enlarged detail view similar to FIG. 1 and showing certain of the parts illustrated in FIG. 1;

FIGS. 3 and 4 are enlarged axial sectional views of disposable pipette tips usable with the pipette pump of the present invention;

FIG. 5 is a fragmentary section similar to FIG. I of an alternative form of the pipette pump; and

FIGS. 6 and 7 are fragmentary side elevational views of the structure illustrated in section in FIG. 5 showing views of the structure in generally the same operating position but with the cap in FIG. 6 being rotated 180 about its axis relative to its position in FIG. 7 so as to show the scales on the opposite sides of the cap.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now more particularly to the drawings, there is illustrated a pipette pump 10 which includes a housing 11, a large piston 12 slidably received and telescoped with the housing 11 and a small piston 13 slidably received and telescoped within the large piston 12. A cap 15 having internal threads 14 is threadedly attached to the small piston 13. The housing 11 has a chamber 16 formed therein, said chamber communicating with a passage 17 which extends through a tip mount or projection 20. The projection 20 functions to mount a pipette tip 79 or 80 (FIGS. 3 and 4) which fits over the projection 20 and which in the case of pipette 80 abuts the radially extending surface 21 adjacent thereto. The tip mount 20 has an outwardly opening recess 22 therein which receives an O-ring 25. The O-ring 25, which may be formed of rubber or other suitable sealing material, assists in providing a sealed connection to the pipette tip so that no leakage occurs between the tip mount 20 and the pipette tip.

The large piston 12 includes a cylindrical portion 26 which is externally covered by an extruded sleeve 27 of a fluorocarbon resin such as Teflon fixedly secured to the cylindrical portion 26. The Teflon sleeve 27 sealingly engages an O-ring 30 which is seated within a recess 31. The Teflon material is slick and thus easily slides against the O-ring 30. The base and one wall of the recess 31 are formed by the housing 11. The other wall of the recess 31 is formed by a lower retainer 32 which squeezes against the O-ring 30 and causes it to sealingly engage the Teflon sleeve 27. The small piston 13 includes a cylindrical rod 35 fixedly embedded within the main body of the piston 13. The rod 35 has an extruded fluorocarbon sleeve 36 such as Teflon fixedly received thereon. The Teflon sleeve 36 slidably engages the O-ring 37 which is squeezed into sealing engagement with the sleeve 36 by means of the retainer 40 in the same fashion that the retainer 32 squeezes the O-ring 30 into sealing engagement with the sleeve 27. Both O-rings 30 and 37 are formed of rubber or other suitable sealing material. It has been found that the above mentioned extruded Teflon sleeves can be moved through their O-rings many hundreds of thousands of times without appreciable wear.

A compression spring 41 is received about the large piston 12 and bears against the radially extending abutment surface 42 of the large piston and also bears against the retainer 32. The spring 41 functions to hold the large piston 12 against a stop pin 45 which extends completely through the housing 11. The large piston 12 has a pair of slots 46 therein which define the limits of movement of the large piston inside the housing 11. The large piston is shown in its projected position, that is, with the spring 41 in its most extended position and holding the large piston 12 with the ends 47 of the slots 46 against the pin 45. The opposite ends 50 of the slots 46 define the other limit of travel of the large piston 12.

The limits of travel of the small piston 13 are in some cases also determined by the pin 45 which extends through a pair of slots in the opposite sidewalls of the small piston 13. Thus the slots 55 have ends 56 which are shown in engagement with the pin 45 and which determine the limit of projection of the small piston 13. The slots 55 also have ends 57 which determine the maximum amount of depression of the small piston 13. Received between the small piston and the retainer 40 is a further compression spring 60. The compression spring 60 acts against an abutment surface 61 on the retainer 40 and also acts against an abutment surface 62 on the small piston 13. The spring 41 is substantially stronger than the spring 60 and is also under a certain amount of precompression when in the illustrated position of the figure. The relative strengths of the springs and the precompression are such that the spring 60 is fully compressed before any compression is effected or any additional compression is effected in the spring 41.

Threadedly received upon the external threaded surface of the small piston 13 is an annular small piston adjustment member 70. The small piston adjustment member can be threaded rightwardly as shown in the drawing to a position closer to the large piston. As shown in the drawing, the annular member 70 is near its most leftwardly adjusted position. In operation, the cap 15 is forced or pressed rightwardly into the housing 11 and the small piston 13 moves rightwardly compressing the spring 60 until such time as the annular member 70 contacts the abutment surface 71 of the large piston 12. At this time, the operator experiences a substantial stop action. Further greater pressure exerted upon the cap 15 toward depressing the cap into the housing causes the spring 41 to be compressed and causes the large piston to be moved rightwardly until the member 75 contacts the pin 45. The member 75 is the large piston adjustment member. The member 75 is externally threaded and can be adjusted to any desired position within the internal threads 78 of the small piston 13 by means of an Allen head screwdriver being received within the Allen head recess 76 in the member 75.

In operation the present device contains all of the liquid within the pipette tip 79 or 80. In order to attach the pipette tip to the tip mount 20, the O-ring 25 should be lubricated with silicon grease. The tip is then placed on the tip mount by using a general pushing and turning motion so that the recess 81 or 82 seats on the O-ring 25. In order to dispense a small volume, the cap 15 is depressed until the first stop is felt. As suggested above this first stop occurs when the small piston adjustment 70 engages the abutment 71 on the leftward end of the large piston 12. The operator should not push the cap rightwardly past this point. Next the disposable tip is placed into the liquid in a container (not shown) and retained there while slowly allowing the cap to return to the original illustrated position. The liquid in the container will thereby be transferred into the disposable tip.

In order to dispense the liquid once it has been so drawn into the disposable tip, the cap is again slowly depressed to the first stop position. The cap is held in that position for approximately one second and then the operator continues to depress the cap at a moderate rate until the second stop is felt. As suggested above the second stop will be felt when the member 75 contacts the pin 45. This procedure will dispense the small volume for which the pipette was calibrated. Calibration of the pipette for a specific volume is, of course, effected by adjusting the position of the small piston adjustment member 70 by screwing the member rightwardly or leftwardly on the small piston 13. This may be effected by a spanner wrench.

in order to obtain and dispense a large volume of liquid, the cap is depressed until the second stop is felt. As mentioned, this occurs when the member 75 contacts the pin 45. The disposable tip is then placed into the liquid and the cap is slowly allowed to return to the illustrated position. The liquid is then dispensed by depressing the cap at a moderate speed until the second stop is reached. The operator should completely depress the cap until the second stop is reached without hesitation at the first stop.

Referring now to FIGS. 5, 6 and 7 there is illustrated an alternative form of the invention which is generally identical to the embodiment of FIG. 1 except that the cap 100 has a threaded recess 101 formed therein which is much deeper than the recess in the embodiment of FIG. 1. The adjustment member 70 is eliminated so that the cap 100 instead contacts the abutment surface 102 of the large piston 105. The position of the cap on the small piston 106 is adjustable by rotation of the cap on the small piston so that the threads 107 move the cap rightwardly or leftwardly relative to the abutment surface 102. The size of the Teflon covered rod corresponding to rod 35 is selected so as to cause one complete 360 rotation of the handle 100 relative to the small piston to produce a change in dispensed volume of a given amount. Referring to FIGS. 6 and 7, it can be seen that housing 110 has an indicator mark 111 thereon. Also the cap 100 has two scales 1 l2 and 115 thereon which are located 180 from one another and which include markings which are intermediate of one another in the axial direction. The indicator mark 111 and the scales 112 and 115 indicate a particular reading when the edge 116 is flush with a particular mark in the scale and when the mark 111 extends perpendicularly from the middle of the particular mark.

it will be noted from the above description that the present invention provides a pipette pump which is less expensive. This is true because the disposable portion of the device includes only the tip and not the complete pump. The pump can be used repeatedly and will have a long service life. It will also be evident from the above description that the present invention is more accurate and more convenient to use than existing pipette arrangements.

The invention claimed is:

1. In a pipette pump, a housing having a chamber therein, said chamber having an opening communicating with atmosphere and through which air is expelled for pumping, a piston reciprocably mounted on said housing for movement in a direction into and out of said chamber, an O-ring of flexible resilient material, said piston being slidable through said O- ring means mounting said O-ring on said housing and squeezing the Oring in sealing engagement with said piston, said piston including a rigid member having a sleeve thereon of extruded fluorocarbon, said sleeve being slidable through said O-ring and in sealing engagement against said O-ring, said sleeve having a constant external cross section taken perpendicularly to its direction of movement into and out of said chamber whereby said sleeve maintains its sealing engagement against said O-ring as said piston is moved into and out of said chamber.

2. A pipette pump comprising a housing, said housing having a chamber therein, said chamber having an opening communicating with atmosphere and through which air is expelled for pumping, a first piston reciprocably mounted on said housing for movement into and out of said chamber, and a second piston reciprocably mounted on said first piston for movement into and out of said chamber.

3. The pipette pump of claim 2 additionally comprising a first spring acting between said housing and said first piston, a' second spring acting between said first piston and said second piston, one of said springs having a substantially different spring rate than the other of said springs whereby depressing of said second piston flexes one of said springs prior to flexing the other of said springs.

4. The pipette pump of claim 2 additionally comprising a first spring acting between said housing and said first piston, a second spring acting between said first piston and said second piston, said second piston being slidable inside of said first piston, stop means mounted on said housing for said first and second pistons, said first spring yieldably retaining said first piston against said stop means, said second spring yieldably retaining said second piston against said stop means, said second piston being movable through a given travel in said first piston and engageable with said first piston to move said first piston through a given travel in said housing, said second spring having a substantially less spring rate than said first spring whereby said second piston must move through its entire travel in said first piston before said first piston moves through its travel in said housing.

5. The pipette pump of claim 4 additionally comprising a first O-ring sealingly mounted on said housing, said first piston being slidable through said first O-ring and sealing against said first O-ring, a second O-ring sealingly mounted on said first piston, said second piston being slidable through said second O-ring and sealing against said second O-ring.

6. The pipette pump of claim 5 additionally comprising a cap threadedly secured to said second piston and slidable in said housing, said cap projecting from said housing and providing means for depressing said pistons.

7. The pipette pump of claim 6 additionally comprising means for adjusting the travel of said second piston in said first piston, said means for adjusting including an annular member threaded onto the exterior of said second piston and engageable with said first piston, and means for adjusting the travel of both of said pistons in said housing, said last-mentioned means including an externally threaded member threadedly received and threadedly adjustable within said second piston and engageable with said first stop means.

8. The pipette pump of claim 6 wherein said cap has a scale thereon and said housing has an indicator marker thereon, said cap being rotatable on said second piston to vary the extent to which said cap is threaded on said second piston, said cap being positioned to engage said second piston when said second piston has moved through its entire travel in said first piston whereupon said cap can move said first piston against the urging of said first spring.

9. The pipette pump of claim 2 additionally comprising a first O-ring sealingly mounted on said housing, said first piston being slidable through said first O-ring and sealing against said first O-ring, a second O-ring sealingly mounted on said first piston, said second piston being slidable through said second O-ring and sealing against said second O-ring.

10. The pump of claim 9 wherein said first piston includes a rigid member having a sleeve thereon of extruded fluorocarbon and wherein said second piston includes a rigid member having a sleeve thereon of extruded fluorocarbon, each of said sleeves being slidable through a respective one of said O-rings 5 and sealing against its respective O-ring.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US1747523 *Nov 2, 1927Feb 18, 1930Mccormick Lewis MontfordSuction lifting device
US2660342 *Apr 1, 1949Nov 24, 1953Ruf HermanBurette with variable capacity
US3045494 *Mar 13, 1958Jul 24, 1962Gerarde Horace WilliamMethod of providing for blood count and pipette and assembly for use therein
US3494201 *Aug 16, 1968Feb 10, 1970Oxford LabPipetting system
US3500689 *Mar 18, 1968Mar 17, 1970American Hospital Supply CorpPipette construction
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3810391 *Jun 19, 1972May 14, 1974Suovaniemi Osmo AnteroAdjustable pipette
US3830108 *Aug 2, 1972Aug 20, 1974Spong FPipetting device
US3834590 *Oct 24, 1972Sep 10, 1974Drummond Scient CoMicroliter fluid delivery apparatus
US3883044 *Mar 30, 1973May 13, 1975Buchler Instr Division NuclearMicropipetter, especially for the discharge of a sample and a diluent
US3933048 *Feb 12, 1974Jan 20, 1976Medical Laboratory Automation, Inc.Pipettes
US4036064 *Sep 11, 1975Jul 19, 1977Gilford Instrument Laboratories, Inc.Pipette device
US4056360 *Feb 17, 1976Nov 1, 1977Risch Gerhard MApparatus for dilution of liquid specimens
US4061037 *Sep 20, 1976Dec 6, 1977Keegan William PPipettes
US4128009 *Aug 11, 1977Dec 5, 1978Marteau D Autry EricAdjustable diluting device
US4133211 *Nov 4, 1977Jan 9, 1979Sarstedt WSuction pipette
US4141250 *May 2, 1977Feb 27, 1979Marteau D Autry EricPlural piston, adjustable diluting device having a volume indicator assembly
US4263257 *Aug 30, 1979Apr 21, 1981Metsaele Seppo JuhaniPipette
US4442722 *Jan 7, 1983Apr 17, 1984Beckman Instruments Inc.Plunger operated pipet
US4734261 *Jan 28, 1986Mar 29, 1988Fuji Photo Film Co., Ltd.Duplex pipette
US4784834 *Dec 12, 1986Nov 15, 1988Glasgeratebau HirschmannPipette
US4824641 *Jun 20, 1986Apr 25, 1989Cetus CorporationSample carrier and pipette tips
US4909991 *Jan 14, 1988Mar 20, 1990Nichiryo Co., Ltd.Tubular body, spring, hollow'shaft, and plunger
US5012682 *Oct 23, 1989May 7, 1991Firma Eppendorf-Netheler-Hinz GmbhPipetting device
US5383372 *Jun 22, 1993Jan 24, 1995Drd Diluter Corp.For obtaining a precise measured dose of a liquid
US5511433 *Dec 16, 1992Apr 30, 1996Eppendorf-Netherler-Hinz GmbhPipette device
US5696330 *Apr 10, 1996Dec 9, 1997Labsystems, Ltd.Phase pipette
US5983733 *Nov 15, 1996Nov 16, 1999Hamilton CompanyManual pipette
US6197259 *Nov 6, 1998Mar 6, 2001Rainin Instrument Co., Inc.Easy eject pipette tip
US6805015May 22, 2003Oct 19, 2004H. Donald SchwartzDual resolution syringe
US7185551Oct 24, 2003Mar 6, 2007Schwartz H DonaldPipetting module
US7641859Nov 18, 2004Jan 5, 2010Matrix Technologies CorporationPipette tip mounting and ejection assembly and associated pipette tip
US8163256Jul 27, 2009Apr 24, 2012Matrix Technologies CorporationPipette tip mounting and ejection assembly and associated pipette tip
DE2505431A1 *Feb 8, 1975Aug 14, 1975Medical Laboratory AutomationPipette
DE2607583A1 *Feb 25, 1976Sep 9, 1976Medical Laboratory AutomationPipette
DE102004055562A1 *Nov 18, 2004Jun 1, 2006Eppendorf AgMetering system for metering liquids in the laboratory comprises a housing, a metering tip, units for detachedly holding the tip on the lower end of the housing, a displacement device, a push-button and a threaded unit
DE102004055562B4 *Nov 18, 2004Sep 28, 2006Eppendorf AgHandhabbares Dosiersystem
Classifications
U.S. Classification73/864.17, 422/932, 73/864.18, 422/510
International ClassificationA61B5/145, G01N1/00, G01F11/06, G01N33/487, G01N33/49, B01L9/06, C01B17/90, A61B5/15, B01L3/02, A61M1/00, G01N33/483, B01L9/00, A61M5/34, A61M5/315, A47G23/02
Cooperative ClassificationA61B5/150244, A61B5/1411, B01L3/0279, A61B5/150259, B01L2300/0838, B01L9/543, B01L3/0241, A61B5/150099, A61B5/14, A61B5/150022, A61M5/315, C01B17/907, B01L3/0282, A61M5/31531, B01L3/0231, A61B5/150236, A61M5/346, B01L2200/04, A61B5/150343, B01L3/0217, A61M5/344, A61M5/347, B01L3/0224, B01L3/0275, A61B5/150213, B01L3/021, A61M1/00, B01L3/0213, B01L9/06
European ClassificationB01L3/02C1, B01L9/543, A61B5/15B4B10, A61B5/15B8J, A61B5/15B8B, A61B5/15B10, A61B5/15B2B, A61B5/15B8N, A61B5/15B8H, B01L3/02F, B01L3/02E, B01L3/02C3D, A61M1/00, A61M5/315, A61M5/34C, A61B5/14, B01L9/06, B01L3/02C3P, B01L3/02C, B01L3/02C3, A61B5/14B2, B01L3/02E2, C01B17/90K, B01L3/02D
Legal Events
DateCodeEventDescription
Jul 5, 1988AS03Merger
Owner name: BOEHRINGER MANNHEIM CORPORATION, A IN CORP.
Owner name: BOEHRINGER MANNHEIM CORPORATION, A NY CORP.
Effective date: 19870625
Jul 5, 1988ASAssignment
Owner name: BOEHRINGER MANNHEIM CORPORATION, A IN CORP.
Free format text: MERGER;ASSIGNOR:BOEHRINGER MANNHEIM CORPORATION, A NY CORP.;REEL/FRAME:004912/0770
Effective date: 19870625
Owner name: BOEHRINGER MANNHEIM CORPORATION
Free format text: MERGER;ASSIGNOR:BOEHRINGER MANNHEIM CORPORATION, A NY CORP.;REEL/FRAME:4912/770
Oct 20, 1986ASAssignment
Owner name: BOEHRINGER MANNHEIM CORPORATION, A CORP. OF NEW YO
Free format text: CHANGE OF NAME;ASSIGNOR:BOEHRINGER MANNHEIM DIAGNOSTICS, INC. A CORP. OF DE.;REEL/FRAME:004624/0055
Effective date: 19861008
Mar 15, 1984ASAssignment
Owner name: BOEHRINGER MANNHEIM DIAGNOSTICS, INC., 9115 HAGUE
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:BIO-DYNAMICS, INC.;REEL/FRAME:004239/0504
Effective date: 19831028