Pipette for sampling and dispensing adjustable volumes of liquids

• US 5,413,006 A
• Filed: 09/28/1993
• Issued: 05/09/1995
• Est. Priority Date: 09/28/1992
• Status: Expired due to Term

• Current Assignee: Gilson, Inc.
• Original Assignee: Gilson Medical Electronics
• Inventors: D'Autry, Eric M.
• Primary Examiner(s): RAEVIS, ROBERT R
• Application Number:
  US08/128,370
• Time in Patent Office: 588 Days
• Field of Search: 73/864.13, 73/864.18, 422/100, 222/309
• US Class Current: 73/864.18
• CPC Class Codes: B01L 2300/026 Drum counters
• CPC Class Codes: B01L 3/0224 having mechanical means to set stroke length, e.g. movable stops B01L3/0231, B01L3/0234 take precedence

Abstract

A pipette body extends along a longitudinal axis and a piston mounted in sliding fashion along this axis inside the said pipette body so as to define a chamber of variable volume emerging at a sampling orifice, said piston being driven over a limited distance of travel in the direction of the sampling orifice by means of pressure manually exerted on a push rod mounted in sliding fashion in the pipette body, and in the opposite direction by the reaction of elastic return means until it abuts against an axial extremity of a metal sheath extending along the said longitudinal axis in side the pipette body. The sheath has an external thread which works by engaging with a thread inside the pipette body in such a way as to move the sheath longitudinally when driven in rotations, in order to adjust the distance of travel of the piston in the opposite direction and the volume of the chamber.

Claims

1. Pipette for sampling and dispensing adjustable volumes of liquid of the type comprising a pipette body extending along a longitudinal axis and a piston mounted in sliding fashion along this axis inside the said pipette body so as to define a chamber of variable volume emerging at a sampling orifice, said piston being driven over a limited distance of travel in the direction of the sampling orifice by means of pressure manually exerted on a push rod mounted in sliding fashion in the pipette body, and in the opposite direction by the reaction of elastic return means until the piston abuts against an axial extremity of a metal sheath extending along the said longitudinal axis inside the pipette body, the sheath having an external thread which works with a thread inside the pipette body in such a way as to move the sheath longitudinally when driven in rotation, in order to adjust the distance of travel of the piston in the opposite direction and the volume of the chamber, a first adjustment knob being secured to the sheath, and also the sheath intermeshing with means for displaying the volume to be dispensed, the push rod being mounted in sliding fashion in the sleeve, wherein:

the push rod has a non-symmetrical cross-section of revolution over at least a portion of its length, the sheath being rigidly locked by locking means to a sleeve arranged coaxially with respect to the sheath and in which the portion of the push rod with a non-symmetric cross-section of revolution is also engaged, the sleeve having an internal profile complementary or homologous to the said portion of the push rod so as to rigidly lock the push rod and sheath in rotation while allowing the push rod to move longitudinally inside the sheath to provide rapid adjustment of the volume to be dispensed.

2. The pipette of claim 1 wherein the sleeve is glued inside the sheath.

3. The pipette of claim 1 wherein the sleeve is received in a bore emerging on the axial extremity of the sheath serving as a distance of travel end stop in the reverse direction of the piston, the radially external face of the sleeve having hollowings to house fixing glue in the bore of the sheath.

4. The pipette of claim 1 wherein the push rod has a portion located outside the pipette body having a button comprising a second adjustment knob with means for rigidly locking the second adjustment knob in rotation with the said push rod and a cover mounted free in rotation about the said longitudinal axis which covers the axial extremity section of the knob located opposite the pipette body.

5. The pipette of claim 1 wherein the said cross-section of the portion of the push rod which is non-symmetrical in revolution engaged in the sleeve is hexagonal.

6. The pipette of claim 1 wherein the sleeve is made from phenylene polysulphide.

7. The pipette of claim 1 wherein the sleeve is glued inside the sheath and the glue is an epoxy glue.

8. Pipette for sampling and dispensing adjustable volumes-of liquid of the type comprising a pipette body extending along a longitudinal axis and a piston mounted in sliding fashion along this axis inside the said pipette body so as to define a chamber of variable volume emerging at a sampling orifice, said piston being driven over a limited distance of travel in the direction of the sampling orifice by means of pressure manually exerted on a push rod mounted in sliding fashion in the pipette body, and in the opposite direction by the reaction of elastic return means until the piston abuts against an axial extremity of a metal sheath extending along the said longitudinal axis inside the pipette body, the sheath having an external thread which works with a thread inside the pipette body in such a way as to move the sheath longitudinally when driven in rotation, in order to adjust the distance of travel of the piston in the opposite direction and the volume of the chamber, a first adjustment knob being secured to the sheath, and the sheath also intermeshing with means for displaying the volume to be dispensed, the push rod being mounted in sliding fashion in the sleeve,

wherein the push rod has a non-symmetrical cross-section of revolution over at least a portion of its length, the sheath being rigidly locked by locking means to a sleeve arranged coaxially with respect to the sheath and in which the portion of the push rod with a non-symmetric cross-section of revolution is also engaged, the sleeve having an internal profile complementary or homologous to the said portion of the push rod so as to rigidly lock the push rod and sheath in rotation while allowing the push rod to move longitudinally inside the sheath to provide rapid adjustment of the volume to be dispensed,

wherein the push rod has a portion located outside the pipette body having a button comprising a second adjustment knob with means for rigidly locking said second adjustment knob it in rotation with the said push rod and a cover mounted free in rotation about the said longitudinal axis which covers the axial extremity section of the 5 knob located opposite the pipette body, and

wherein the means for rigidly locking the second adjustment knob in rotation with the push rod comprise two longitudinal slots formed on two diametrically opposed sides of the push rod and which engage with two projecting ribs of complementary profile on the bearing surface of the second adjustment knob.

9. The pipette of claim 8 wherein the cover is mounted free in rotation on the push rod and held axially onto it by complementarity of shapes.

10. The pipette of claim 8 wherein the cover is mounted free in rotation on the second adjustement knob and held axially onto it by complementarity of shapes.

11. Pipette for sampling and dispensing adjustable volumes of liquid of the type comprising a pipette body extending along a longitudinal axis and a piston mounted in sliding fashion along this axis inside the said pipette body so as to define a chamber of variable volume emerging at a sampling orifice, said piston being driven over a limited distance of travel in the direction of the sampling orifice by means of pressure manually exerted on a push rod mounted in sliding fashion in the pipette body, and in the opposite direction by the reaction of elastic return means until the piston abuts against an axial extremity of a metal sheath extending along the said longitudinal axis inside the pipette body, the sheath having an external thread which works with a thread inside the pipette body in such a way as to move the sheath longitudinally when driven in rotation, in order to adjust the distance of travel of the piston in the opposite direction and the volume of the chamber, a first adjustment knob being secured to the sheath, and also the sheath intermeshing with means for displaying the volume to be dispensed, the push rod being mounted in sliding fashion in the sleeve,

wherein the push rod has a non-symmetrical cross-section of revolution over at least a portion of its length, the sheath being rigidly locked by locking means to a sleeve arranged coaxially with respect to the sheath and in which the portion of the push rod with a non-symmetric cross-section of revolution is also engaged, the sleeve having an internal profile complementary or homologous to the said portion of the push rod so as to rigidly lock the push rod and sheath in rotation while allowing the push rod to move longitudinally inside the sheath to provide rapid adjustment of the volume to be dispensed,

wherein the sleeve is received in a bore emerging on the axial extremity of the sheath as a distance of travel end stop in the reverse direction of the piston, the radially external face of the sleeve having hollowings to house fixing glue in the bore of the sheath;

and

wherein the said hollowings provided on the external surface of the sleeve are made up of longitudinal flat parts extending axially over only a 5 portion of the length of the sleeve.

12. The pipette of claim 11 wherein these hollowings are made of three longitudinal flat parts equally distributed angularly about a longitudinal axis of symmetry for the sleeve and symmetrically extending axially either side of a transverse plane of symmetry P for the sleeve.

13. Pipette for sampling and dispensing adjustable volumes of liquid of the type comprising a pipette body extending along a longitudinal axis and a piston mounted in sliding fashion along this axis inside the said pipette body so as to define a chamber of variable volume emerging at a sampling orifice, said piston being driven over a limited distance of travel in the direction of the sampling orifice by means of pressure manually exerted on a push rod mounted in sliding fashion on the pipette body, and in the opposite direction by the reaction of elastic return means until the piston abuts against an axial extremity of a metal sheath extending along the said longitudinal axis inside the pipette body, the sheath having an external thread which works with a thread inside the pipette body in such a way as to move the sheath longitudinally when driven in rotation, in order to adjust the distance of travel of the piston in the opposite direction and the volume of the chamber, a first adjustment knob being secured to the sheath, and the sheath also intermeshing with means for displaying the volume to be dispensed, the push rod being mounted in sliding fashion in the sleeve, wherein:

the push rod has non-symmetrical cross section of revolution over at least a portion of its length, the sheath being rigidly locked by locking means to a sleeve arranged coaxially with respect to the sheath and in which the portion of the push rod with a non-symmetric cross-section of revolution is also engaged, the sleeve having an internal profile complementary or homologous to the said portion of the push rod so as to rigidly lock the push rod and sheath in rotation while allowing the push rod to move longitudinally inside the sheath to provide rapid adjustment of the volume to be dispensed, and

wherein the sleeve is received in a bore emerging on the axial extremity of the sheath serving as a distance of travel end stop in the reverse direction of the piston, the radially external face of the sleeve having hollowings to house fixing glue in the bore of the sheath.

14. Pipette for sampling and dispensing adjustable volumes of liquid of the type comprising a pipette body extending along a longitudinal axis and a piston mounted in sliding fashion along this axis inside the said pipette body so as to define a chamber of variable volume emerging at a sampling orifice, said piston being driven over a limited distance of travel in the direction of the sampling orifice by means of pressure manually exerted on a push rod mounted in sliding fashion in the pipette body, and in the opposite direction by the reaction of elastic return means until the piston abuts against an axial extremity of a metal sheath extending along the said longitudinal axis inside the pipette body, the sheath having an external thread which works with a thread inside the pipette body in such a way as to move the sheath longitudinally when driven in rotation, in order to adjust the distance of travel of the piston in the opposite direction and the volume of the chamber, a first adjustment knob being secured to the sheath, and the sheath also intermeshing with means for displaying the volume to be dispensed, the push rod being mounted in sliding fashion in the sleeve, wherein:

the push rod has non-symmetrical cross section of revolution over at least a portion of its length, the sheath being rigidly locked by locking means to a sleeve arranged coaxially with respect to the sheath and in which the portion of the push rod with a non-symmetric cross-section of revolution is also engaged, the sleeve having an internal profile complementary or homologous to the said portion of the push rod so as to rigidly lock the push rod and sheath in rotation while allowing the push rod to move longitudinally inside the sheath to provide rapid adjustment of the volume to be dispensed, and

wherein the push rod has a portion located outside the pipette body having a button comprising a second adjustment knob with means for rigidly locking the second adjustment knob in rotation with the said push rod and a cover mounted free in rotation about the said longitudinal axis which covers the axial extremity section of the knob located opposite the pipette body.

15. Pipette for sampling and dispensing adjustable volumes of liquid of the type comprising a pipette body extending along a longitudinal axis and a piston mounted in sliding fashion along this axis inside the said pipette body so as to define a chamber of variable volume emerging at a sampling orifice, said piston being driven over a limited distance of travel in the direction of the sampling orifice by means of pressure manually exerted on a push rod mounted in sliding fashion in the pipette body, and in the opposite direction by the reaction of elastic return means until the piston abuts against an axial extremity of a metal sheath extending along the said longitudinal axis inside the pipette body, the sheath having an external thread which works with a thread inside the pipette body in such a way as to move the sheath longitudinally when driven in rotation, in order to adjust the distance of travel of the piston in the opposite direction and the volume of the chamber, a first adjustment knob being secured to the sheath, and the sheath also intermeshing with means for displaying the volume to be dispensed, the push rod being mounted in sliding fashion in the sleeve, wherein:

the push rod has non-symmetrical cross section of revolution over at least a portion of its length, the sheath being rigidly locked by locking means to a sleeve arranged coaxially with respect to the sheath and in which the portion of the push rod with a non-symmetric cross-section of revolution is also engaged, the sleeve having an internal profile complementary or homologous to the said portion of the push rod so as to rigidly lock the push rod and sheath in rotation while allowing the push rod to move longitudinally inside the sheath to provide rapid adjustment of the volume to be dispensed,

wherein the push rod has a portion located outside the pipette body having a button comprising a second adjustment knob with means for rigidly locking the second adjustment knob in rotation with the said push rod and a cover mounted free in rotation about the said longitudinal axis which covers the axial extremity section of the knob located opposite the pipette body, and

wherein the means for rigidly locking the second adjustment knob in rotation with the push rod comprise two longitudinal slots formed on two diametrically opposite sides of the push rod and which engage with two projecting ribs of complementary profile on the bearing surface of the second adjustment knob, and wherein the cover is mounted free in rotation on the push rod and held axially onto it by complementarity of shapes.

16. Pipette for sampling and dispensing adjustable volumes of liquid of the type comprising a pipette body extending along a longitudinal axis and a piston mounted in sliding fashion along this axis inside the said pipette body so as to define a chamber of variable volume emerging at a sampling orifice, said piston being driven over a limited distance of travel in the direction of the sampling orifice by means of pressure manually exerted on a push rod mounted in sliding fashion in the pipette body, and in the opposite direction by the reaction of elastic return means until the piston abuts against an axial extremity of a metal sheath extending along the said longitudinal axis inside the pipette body, the sheath having an external thread which works with a thread inside the pipette body in such a way as to move the sheath longitudinally when driven in rotation, in order to adjust the distance of travel of the piston in the opposite direction and the volume of the chamber, a first adjustment knob being secured to the sheath, and the sheath also intermeshing with means for displaying the volume to be dispensed, the push rod being mounted in sliding fashion in the sleeve, wherein:

the push rod has non-symmetrical cross section of revolution over at least a portion of its length, the sheath being rigidly locked by locking means to a sleeve arranged coaxially with respect to the sheath and in which the portion of the push rod with a non-symmetric cross-section of revolution is also engaged, the sleeve having an internal profile complementary or homologous to the said portion of the push rod so as to rigidly lock the push rod and sheath in rotation while allowing the push rod to move longitudinally inside the sheath to provide rapid adjustment of the volume to be dispensed,

wherein the push rod has a portion located outside the pipette body having a button comprising a second adjustment knob with means for rigidly locking the second adjustment knob in rotation with the said push rod and a cover mounted free in rotation about the said longitudinal axis which covers the axial extremity section of the knob located opposite the pipette body,

wherein the means for rigidly locking the second adjustment knob in rotation with the push rod comprise two longitudinal slots formed on two diametrically opposed sides of the push rod and which engage with two projecting ribs of complementary profile on the bearing surface of the second adjustment knob and held axially onto it by complementarity of shapes.