Liquid transfer pipetting device with a tip ejector

Claim 2

In a liquid transfer pipetting device that includes a hollow barrel shaped handle member, a piston chamber within said barrel, said piston chamber having first and second ends, a piston element in said piston chamber that extends through said first piston chamber end, means extending through one end of said barrel member for imparting reciprocal motion to said piston element, resilient means within said barrel for normally urging said piston element to a rest position toward said first end of said piston chamber, and means extending from an opposite end of said barrel for engaging a hollow detachable tip and for providing fluid communication between said second end of said piston chamber and an internal portion of said tip, the improvement comprising mechanical means associated with said tip holding means and responsive to manual actuation for disengaging a detachable tip from said tip holding means, said tip disengaging means includes a pair of cooperating cam lobes held in a manner that rotation of an actuator with respect to said handle member causes an ejecting means associated with said detachable tip engaging means to force a tip therefrom upon rotation of the actuator.

Claim 3

In a hand-held liquid transfer pipetting device that includes a manually actuated fluid pump within an enclosure member for providing fluid communication from said fluid pump to an end of said tube member remote from the enclosure, said remote tube member end being shaped for a segment to frictionally engage an interior surface of a hollow detachable tip, the improvement comprising: a hollow sleeve held on said tube member in a manner to be rotatable with respect thereto and also movable along its length from a first position wherein said tip engaging segment of the tube member remains uncovered to a second sleeve position wherein at least a significant portion of said tip engaging segment of the tube member is covered, thereby permitting disengagement of a tip by breaking the frictional bond therebetween as the sleeve is moved from its said first to its said second position, resilient means positioned for normally holding said hollow sleeve in its said first position, whereby a detachable tip is removed by moving said sleeve against the force of said resilient means, and means cooperatively shaped between said tube member and said sleeve for converting rotational motion therebetween into movement of the sleeve along said tube into said second sleeve position, whereby rotation of said sleeve causes a tip to be ejected from frictional engagement with said remote tube member end.

Claim 4

In a hand-held liquid transfer pipetting device that includes a manually actuated fluid pump within an enclosure member for providing fluid communication from said fluid pump to an end of said tube member remote from the enclosure, said remote tube member end being shaped for a segment to frictionally engage an interior surface of a hollow detachable tip, the improvement comprising: a hollow sleeve held on said tube member in a manner to be rotatable with respect thereto and also movable along its length from a first position wherein said tip engaging segment of the tube member remains uncovered to a second sleeve position wherein at least a significant portion of said tip engaging segment of the tube member is covered, thereby permitting disengagement of a tip by breaking the frictional bond therebetween as the sleeve is moved from its said first to its said second position, resilient means positioned for normally holding said hollow sleeve in its said first position, whereby a detachable tip is removed by moving said sleeve against the force of said resilient means, and means cooperatively shaped between said tube member and said sleeve for converting rotational motion therebetween into movement of the sleeve along said tube into said second sleeve position, whereby rotation of said sleeve causes a tip to be ejected from frictional engagement with said remote tube member end.

Claim 5

The improved pipetter according to claim 2 which additionally comprises a resilient means for normally holding said hollow sleeve in Its said first position, whereby a detachable tip is removed by moving said sleeve against the force of said resilient means.

Claim 6

In a hand-held liquid transfer pipetting device that includes a manually actuated fluid pump within an enclosure member for providing fluid communication from said fluid pump to an end of said tube member remote from the enclosure, said remote tube member end being shaped for a segment to frictionally engage an interior surface of a hollow detachable tip, the improvement comprising: a hollow sleeve held on said tube member and movable along its length from a first position wherein said tip engaging segment of the tube member remains uncovered to a second sleeve position wherein at least a significant portion of said tip engaging segment of the tube member is covered, thereby permitting disengagement of a tip by breaking the frictional bond therebetween as the sleeve is moved from its said first to its said second position, a resilient means for normally holding said hollow sleeve in its said first position, whereby a detachable tip is removed by moving said sleeve against the force of said resilient means, and a first cam lobe attached to said enclosure member, a second mating cam lobe held fixed with respect to said sleeve and means for rotating said cam lobes with respect to one another, thereby providing movement of said sleeve between its said first and second positions in response to rotation of said lobe rotating means.

Claim 7

In a hand-held liquid transfer pipetting device that includes a manually actuated fluid pump within an enclosure member for providing fluid communication from said fluid pump to an end of said tube member remote from the enclosure, said remote tube member end being shaped for a segment to frictionally engage an interior surface of a hollow detachable tip, the improvement comprising: a hollow sleeve held on said tube member and movable along its length from a first position wherein said tip engaging segment of the tube member remains uncovered to a second sleeve position wherein at least a significant portion of said tip engaging segment of the tube member is covered, thereby permitting disengagement of a tip by breaking the frictional bond therebetween as the sleeve is moved from its said first to its said second position, a resilient means for normally holding said hollow sleeve in its said first position, whereby a detachable tip is removed by moving said sleeve against the force of said resilient means, and a first cam lobe attached to said enclosure member, a second mating cam lobe held fixed with respect to said sleeve and means for rotating said cam lobes with respect to one another, thereby providing movement of said sleeve between its said first and second positions in response to rotation of said lobe rotating means.

Claim 8

In a hand-held liquid transfer pipetting device that includes a manually actuated fluid pump within an enclosure member, and a hollow tube-like member extending from said enclosure member for providing fluid communication from said pump to an end of said tube member remote from the enclosure, said remote tube member end being shaped for holding an interior surface of a hollow detachable tip, the improvement comprising: a hollow cylindrical sleeve held on said tube in a manner to be movable both longitudinally and rotatably with respect to said tube member, a coiled spring positioned within said sleeve and around the outside of said tube member, said spring being attached in a manner to normally urge said sleeve toward said enclosure member, a first cam lobe attached as part of said enclosure member and extending outward adjacent said tube member, and an actuator fixed to said sleeve at its end adjacent the enclosure member, said actuator including a second cam lobe extending toward said enclosure member for engaging said first cam when the actuator is rotated with respect to the to the enclosure member, thereby to provide lateral movement of said sleeve along the tube member for disengagement of a tip frictionally held at a remote end of said tube member.

Claim 9

In a hand-held liquid transfer pipetting device that includes a manually actuated fluid pump within an enclosure member, and a hollow tube-like member extending from said enclosure member for providing fluid communication from said pump to an end of said tube member remote from the enclosure, said remote tube member end being shaped for holding an interior surface of a hollow detachable tip, the improvement comprising: a hollow cylindrical sleeve held on said tube in a manner to be movable both longitudinally and rotatably with respect to said tube member, a coiled spring positioned within said sleeve and around the outside of said tube member, said spring being attached in a manner to normally urge said sleeve toward said enclosure member, a first cam lobe attached as part of said enclosure member and extending outward adjacent said tube member, and an actuator fixed to said sleeve at its end adjacent the enclosure member, said actuator including a second cam lobe extending toward said enclosure member for engaging said first cam when the actuator is rotated with respect to the to the enclosure member, thereby to provide lateral movement of said sleeve along the tube member for disengagement of a tip frictionally held at a remote end of said tube member.

Claim 10

The improved pipetter according to claim 5 wherein said actuator includes a third cam lobe positioned 180* from said second cam lobe, whereby the actuator need be rotated a maximum of 180* to produce the desired laterla movement for removal of a detachable tip.

Claim 11

The improved pipetter of claim 5 wherein said actuator includes a cylindrically shaped sleeve positioned to shield said first and second cam lobes.