Pipette apparatus

Claim 2

Pipetting apparatus comprising: a body including an internal bore therein having a shoulder located at a selected depth within the internal bore, the body having a narrowing portion comprising a volume cylinder which is hollowed to form a volume chamber which is axially spaced away from said body internal bore and which communicates with said internal bore through an axially aligned aperture within the body; sleeve means mounted within said body for slidable movement therewithin in a direction substantially along the axis of said internal bore; a plunger including a volume rod attached thereto mounted within said body for slidable movement therewithin with said plunger slidably movable within said internal bore and with said volume rod protruding through said aperture into said volume chamber; coupling means between said plunger and said sleeve means for engaging the sleeve means to slide with said plunger within said body only over a preselected nearer portion of the slidable movement of the plunger which is near the shoulder of the internal bore and for disengaging the sleeve means from said plunger over a remaining portion of the slidable movement of said plunger which is remote from said shoulder; first spring means disposed within said body for resiliently biasing said plunger away from said shoulder; second spring means disposed within said body to resiliently bias said sleeve means with respect to said body for yieldably maintaining said sleeve means in fixed position of disengagement from the plunger during said remaining remote portion of slidable movement thereof; and electrical switch means disposed within said body to be actuated in response To sliding movement of said sleeve means with said plunger during said preselected nearer portion of the movement thereof.

Claim 3

Pipetting apparatus as in claim 1 wherein: said plunger includes a manually-actuatable push rod coupled thereto to protrude from the end of said body remote from said shoulder in substantially coaxial alignment with said plunger; said body includes substantially diametrically opposed, laterally extending portions near the end of the body from which said push rod protrudes; and said switch means is supported within a laterally extending portion of the body to be actuated by sliding movement of said sleeve means within said internal bore of the body.

Claim 4

Pipetting apparatus comprising: a body including an internal bore therein having a shoulder located at a selected depth within the internal bore, the body having a narrowing portion comprising a volume cylinder which is hollowed to form a volume chamber which is axially spaced away from said body internal bore and which communicates with said internal bore through an axially aligned aperture within the body; sleeve means mounted within said body for slidable movement therewithin in a direction substantially along the axis of said internal bore; a plunger including a volume rod attached thereto mounted within said body for slidable movement therewithin with said plunger slidably movable within said internal bore and with said volume rod protruding through said aperture into said volume chamber; coupling means between said plunger and said sleeve means for engaging the sleeve means to slide with said plunger within said body only over a preselected nearer portion of the slidable movement of the plunger which is near the shoulder of the internal bore and for disengaging the sleeve means from said plunger over a remaining portion of the slidable movement of said plunger which is remote from said shoulder; first spring means disposed within said body for resiliently biasing said plunger away from said shoulder; second spring means disposed within said body to resiliently bias said sleeve means with respect to said body for yieldably maintaining said sleeve means in fixed position of disengagement from the plunger during said remaining remote portion of slidable movement thereof; a liquid-holding tip for said apparatus having a tapered internal bore which communicates with an orifice at the narrow end of the tip and with a connection port at the wide end within which the distal end of the volume cylinder is inserted; said tip includes volumetric graduations thereon for visually measuring a volume of liquid within the region of the internal tapered bore thereof adjacent said orifice; and the extreme outside lateral dimension of the volume cylinder near the distal end thereof corresponds with the internal dimension of the tapered bore in said tip for sealingly engaging the internal tapered bore of said tip above and proximate the volumetric graduation that is representative of said volume rod protruding into said volume chamber by the amount of the calibrated portion of slidable movement of said plunger.

Claim 5

Pipetting apparatus comprising: a body including an internal bore therein having a shoulder located at a selected depth within the internal bore, the body having a narrowing portion comprising a volume cylinder which is hollowed to form a volume chamber which is axially spaced away from said body internal bore and which communicates with said internal bore through an axially aligned aperture within the body; sleeve means mounted within said body for slidable movement therewithin in a direction substantially along the axis of said internal bore; a plunger including a volume rod attached thereto mounted within said body for slidable movement therewithin with said plunger slidably movable within said internal bore and with said volume rod protruding through said aperture into said volume chamber; coupling means between said plunger and said sleeve means for engaging the sleeve means to slide with said plunger within said body only over a preselected nearer portion of the slidable movement of the plunger which is near the shoulder of the internal bore and for disengaging the sleeve means from said plunger over a remaining portion of the slidable movement of said plunger which is remote from said shoulder; first spring means disposed within said body for resiliently biasing said plunger away from said shoulder; second spring means disposed within said body to resiliently bias said sleeve means with respect to said body for yieldably maintaining said sleeve means in fixed position of disengagement from the plunger during said remaining remote portion of slidable movement thereof; a liquid-holding tip for said apparatus having a tapered internal bore which communicates with an orifice at the narrow end of the tip and with a connection port at the wide end within which the distal end of the volume cylinder is inserted; said tip includes volumetric graduations thereon for visually measuring a volume of liquid within the region of the internal tapered bore thereof adjacent said orifice; and the extreme outside lateral dimension of the volume cylinder near the distal end thereof corresponds with the internal dimension of the tapered bore in said tip for sealingly engaging the internal tapered bore of said tip above and proximate the volumetric graduation that is representative of said volume rod protruding into said volume chamber by the amount of the calibrated portion of slidable movement of said plunger.

Claim 6

A universal liquid-holding tip adapted to attach to the inlet and discharge ends of pipetting apparatus having end diameters that are representative of the maximum capacities of the pipetting apparatus, the tip comprising: an elongated vessel having an internal bore which communicates with and diverges from an orifice at the narrow end of the vessel and which also communicates with a connection port at the wide end of the vessel, said elongated vessel having volumetric graduations thereon from the orifice end thereof corresponding substantially to the maximum capacities of pipetting apparatus to be associated therewith; and the divergence of the internal bore providing sealing engagement with the end of associated pipetting apparatus at a depth within the internal bore that substantially corresponds with a volumetric graduation for a liquid volume in the region adjacent the orifice which is not less than the maximum capacity of the associated pipetting apparatus.

Claim 7

A universal liquid-holding tip adapted to attach to the inlet and discharge ends of pipetting apparatus having end diameters that are representative of the maximum capacities of the pipetting apparatus, the tip comprising: an elongated vessel having an internal bore which communicates with and diverges from an orifice at the narrow end of the vessel and which also communicates with a connection port at the wide end of the vessel, said elongated vessel having volumetric graduations thereon from the orifice end thereof corresponding substantially to the maximum capacities of pipetting apparatus to be associated therewith; and the divergence of the internal bore providing sealing engagement with the end of associated pipetting apparatus at a depth within the internal bore that substantially corresponds with a volumetric graduation for a liquid volume in the region adjacent the orifice which is not less than the maximum capacity of the associated pipetting apparatus.