Pipettes

Claim 2

A manual pipette adapted to have a disposable tip wedge fitted at one end thereof and in co-axial relationship thereto, the arrangement being such that a disposable tip is secured to the pipette only by the frictional force of the wedge fit, said pipette comprising a de-tipping member for removing a disposable tip that is wedge fitted to the pipette, said member being slideably mounted on said pipette in a direction parallel to the axis of the pipette and movable between a normal position away from a disposable tip and a position where it engages the end of a disposable tip and thereafter pushes the tip in an axial direction to free it from frictional engagement with the pipette.

Claim 3

A manual pipette according to claim 1 including resilient means for biasing said de-tipping member to its normal position.

Claim 4

A manual pipette according to claim 1 wherein said de-tipping member is a sleeve member concentric with the pipette.

Claim 5

A manual pipette according to claim 3 including spring means for biasing said sleeve member to its normal position.

Claim 6

A manual pipette according to claim 4 wherein said pipette comprises an elongated tubular member on which a disposable tip is wedge fitted, a finger grip member connected to said elongated tubular member, a plunger assembly mounted within said finger grip member for sliding movement between two stop positions, an adjustment means for determining one of said positions, means for biasing said plunger assembly to the position determined by said adjustment means, and wherein said sleeve member biasing spring means is a compression spring fitted over said tubular member, and including means secured to said tubular member for restraining one end of said compression spring while its remote end bears against said sleeve member and urges said sleeve member to its normal position.

Claim 7

A manual pipette according to claiam 5 wherein said adjustment means is adjustably connected to said finger grip member, and including locking means for securing said adjustment means in its adjusted position.

Claim 8

A manual pipette according to claiam 5 wherein said adjustment means is adjustably connected to said finger grip member, and including locking means for securing said adjustment means in its adjusted position.

Claim 9

A manual pipette adapted to have a disposable tip wedge fitted at the end thereof, said pipette comprising a permanent tip member, a sleeve member within which said permanent tip member slides and from which said permanent tip member projects, and spring means for biasing said permanent tip member to its projected position whereby when a disposable tip is being wedge fitted to said permanent tip member as by the pipette being held by said sleeve member and said permanent tip member pressed into engagement with a disposable tip, the force urging said permanent tip member into engagement with the disposable tip is determined by said spring means.

Claim 10

A manual pipette adapted to have a disposable tip wedge fitted at the end thereof, said pipette comprising a permanent tip member, a sleeve member within which said permanent tip member slides and from which said permanent tip member projects, and spring means for biasing said permanent tip member to its projected position whereby when a disposable tip is being wedge fitted to said permanent tip member as by the pipette being held by said sleeve member and said permanent tip member pressed into engagement with a disposable tip, the force urging said permanent tip member into engagement with the disposable tip is determined by said spring means.

Claim 11

A manual pipette according to claim 7 wherein said permanent tip member projects from said sleeve member by a predetermined distance so that when a disposable tip is being wedge fitted to said permanent tip member the end of said sleeve member will engage the end of the disposable tip and the force urging said permanent tip member into engagement with the disposable tip will be determined and limited by said spring means and its amount of compression.

Claim 12

A pipette adapted to have a disposable tip mounted at one end thereof, said pipette comprising, a permanent tip member to which a disposable tip is frictionally joined so as to form an air-tight connection, and disposable tip removing means for removing a disposable tip from said permanent tip member, said permanent tip member and said disposable tip removing means being supported so as to enable relative movement therebetween as a result of which a disposable tip is disconnected from said permanent tip member.

Claim 13

A pipette adapted to have a disposable tip mounted at one end thereof, said pipette comprising, a permanent tip member to which a disposable tip is frictionally joined so as to form an air-tight connection, and disposable tip removing means for removing a disposable tip from said permanent tip member, said permanent tip member and said disposable tip removing means being supported so as to enable relative movement therebetween as a result of which a disposable tip is disconnected from said permanent tip member.

Claim 14

A pipette according to claim 9 wherein the disposable tip is a hollow conical element and said permanent tip member is adapted to fit within the disposable tip which is frictionally held thereon, and wherein the relative movement between said permanent tip member and said disposable tip removing means causes the latter to bear against the end of the disposable tip and thereby to push it off said permanent tip member.

Claim 15

A pipette according to claim 10 including resilient means for biasing the end of said permanent tip member on which a disposable tip is held and the bearing end of said disposable tip removing means away from each other.

Claim 16

A pipette according to claim 11 including a grip member means integrally connected with but spaced from said permanent tip member, and wherein said disposable tip removing means is a sleeve-like unit that encloses said permanent tip member but leaves the end thereof projecting from the sleeve-like unit, and wherein said disposable tip removing member is biased into abutting relationship with said grip member means by said resilient means.

Claim 17

A pipette according to claim 10 including means to effect relative movement between said permanent tip member and said disposable tip removing means whereby a disposable tip is removed from said permanent tip member.

Claim 18

A manual pipette comprising a permanent tip member adapted to have a disposable tip coupled thereto in an air-tight relationship, means for drawing a liquid into and for expelling it from a disposable tip coupled to said permanent tip member, and means independent of said last named means disposed adjacent said permanent tip member and in spaced relationship from the end thereof to which a disposable tip is coupled for dislodging a disposable tip from said permanent tip member when a relative sliding motion between said permanent tip member and said dislodging means is effected.

Claim 19

A manual pipette comprising a permanent tip member adapted to have a disposable tip coupled thereto in an air-tight relationship, means for drawing a liquid into and for expelling it from a disposable tip coupled to said permanent tip member, and means independent of said last named means disposed adjacent said permanent tip member and in spaced relationship from the end thereof to which a disposable tip is coupled for dislodging a disposable tip from said permanent tip member when a relative sliding motion between said permanent tip member and said dislodging means is effected.

Claim 20

A manual pipette according to claim 14 including spring means for biasing said permanent tip member and said disposable tip dislodging means to said spaced relationship.

Claim 21

A manual pipette according to claim 15 including means for applying a force to overcome the force exerted by said spring means and thereby effect a relative movement between said permanent tip member and said disposable tip dislodging means.

Claim 22

A manual pipette comprising a permanent tip member adapted to have a disposable tip frictionally connected to the outside surface of said member, a tip removing member adjacent the outside surface of said permanent tip member, and means supporting said members for relative movement therebetween whereby as a result of such movement a disposable tip is engaged by said tip removing member and freed from its frictional connection with said permanent tip member.

Claim 23

A manual pipette comprising a permanent tip member adapted to have a disposable tip frictionally connected to the outside surface of said member, a tip removing member adjacent the outside surface of said permanent tip member, and means supporting said members for relative movement therebetween whereby as a result of such movement a disposable tip is engaged by said tip removing member and freed from its frictional connection with said permanent tip member.