Chemical apparatus and process disinfecting – deodorizing – preser – Control element responsive to a sensed operating condition
Reexamination Certificate
2001-01-12
2003-07-22
Ludlow, Jan (Department: 1743)
Chemical apparatus and process disinfecting, deodorizing, preser
Control element responsive to a sensed operating condition
C422S091000, C073S864010
Reexamination Certificate
active
06596240
ABSTRACT:
BACKGROUND OF THE INVENTION
Pipettes and pipette tips come in many configurations. Seals between the pipette and the tip can be formed in several different ways: two conical surfaces coming together, raised rings forming annular pressure points, and a blunt corner or radiused corner forced into a conical tip. To insure a good seal, a technical must insert the pipette into the pipette tip with enough force to affect a seal by displacing plastic in the tip. In some instances this can be considerable.
One solution is proposed in U.S. Pat. No. 4,748,859 to Magnussen, Jr., et al. A disposable pipette tip member is disclosed having three inner coaxial annular sealing bands spaced axially from an open proximal end for receiving a conical pipette tip mounting shaft. The first two sealing bands are relatively resilient and simultaneously engage, guide and laterally support the pipette shaft as it enters the tip member to form annular fluid-tight seals with the shaft. The third band is relatively rigid and upon engagement with the shaft, forms a third annular fluid-tight seal and a controllable stop for the shaft such that the tip member is seated on the shaft adjacent the pipette tip ejector mechanism.
Removal of the tip can be difficult as well, and over many uses during a day, can cause fatigue and even injury over time. A need exists for a method for producing a pipette tip that can be inserted and ejected with a minimal force, maintain a good seal, and provide for a good fit on a variety of pipettes.
Also, a need exists for a method of forming relatively large and resilient rings on the internal sealing surface of the pipette tip. Typically, the size of an internal ring is limited since it is “undercut” in the mold that forms the tip. In order to remove the part from the mold, it must expand for the ring to be released from the groove on the mold core that forms it. This limits its size, and can “smear” the ring as it is removed.
SUMMARY OF THE INVENTION
The present invention is directed to a pipette tip member for releasably mating with a pipette shaft. The tip member comprises an elongated tubular receptacle having a central axis, a protrusion on an inner surface of the receptacle, and a recess on the inner surface adjacent the protrusion. The tip member can have a generally conical shape and the inner surface is tapered from a rear opening at a proximal end to a tip opening at a distal end.
In one embodiment the protrusion extends around the inner surface to form an annular sealing ring and the recess extends around the inner surface to form an annular groove.
The protrusion preferably has a V-shaped axial cross section. In one embodiment the protrusion has first and second generally straight edges that intersect at an angle between about 30° and about 120°, preferably between about 45° and about 90°. In another embodiment, the first and second edges intersect at an angle of about 60°.
The recess preferably has a generally circular axial cross section and at least a portion of the recess is collinear with at least a portion of the protrusion. In one embodiment the tip member extends from a rear opening at a proximal end to a tip opening at a distal end and the recess is disposed proximal to the protrusion in the axial direction.
In one embodiment the recess extends radially outward from the inner surface and has a depth and the protrusion extends radially inward from the inner surface and has a height and the recess depth is about as great as the protrusion height. In another embodiment the recess depth is greater than the protrusion height.
The present invention is also directed to a method of forming a tubular pipette tip member, comprising the steps of: providing a mold including a mold core with a conical shape and including a mold protrusion disposed adjacent and proximal to a mold recess, introducing mold material into the mold; and removing the mold material by forcing the mold material off of the mold core. In one embodiment, during the step of removing the mold material, the mold material is forced radially outward by the mold protrusion and the tip protrusion is lifted radially outward from the mold recess. In yet another embodiment, during the step of removing the mold material, the tip protrusion is spaced from the mold core after tip protrusion is lifted out of the mold recess.
REFERENCES:
patent: 3732734 (1973-05-01), Avakian
patent: 4072330 (1978-02-01), Brysch
patent: 4187724 (1980-02-01), Citrin
patent: D255601 (1980-06-01), De Vaughn
patent: D256052 (1980-07-01), De Vaughn
patent: D274651 (1984-07-01), De Vaughn
patent: 4487081 (1984-12-01), De Vaughn et al.
patent: D286570 (1986-11-01), Williams
patent: 4679446 (1987-07-01), Sheehan et al.
patent: 4707337 (1987-11-01), Jeffs et al.
patent: D297054 (1988-08-01), Williams
patent: 4824641 (1989-04-01), Williams
patent: 4917274 (1990-04-01), Asa et al.
patent: 4961350 (1990-10-01), Tennstedt
patent: 4999164 (1991-03-01), Puchinger et al.
patent: 5032343 (1991-07-01), Jeffs et al.
patent: 5200151 (1993-04-01), Long
patent: 5232669 (1993-08-01), Pardinas
patent: 5496523 (1996-03-01), Gazit et al.
patent: 5556598 (1996-09-01), Raybuck et al.
patent: D384418 (1997-09-01), Torti et al.
patent: 5779984 (1998-07-01), Kelly et al.
patent: 5807524 (1998-09-01), Kelly et al.
patent: 5833927 (1998-11-01), Raybuck et al.
patent: 5851491 (1998-12-01), Moulton
patent: D414562 (1999-09-01), Tajima
patent: D416625 (1999-11-01), Torti et al.
patent: 6045757 (2000-04-01), Moriarty et al.
patent: 6066297 (2000-05-01), Torti et al.
patent: 6117394 (2000-09-01), Smith
patent: 0 148 333 (1985-07-01), None
patent: 0 733404 (1996-09-01), None
patent: 0 743 095 (1996-11-01), None
patent: 2 172 218 (1986-09-01), None
patent: WO 90/14162 (1990-11-01), None
patent: WO 91/16975 (1991-11-01), None
patent: WO 00/27528 (2000-05-01), None
patent: WO 0027529 (2000-05-01), None
patent: WO 0027530 (2000-05-01), None
New ProGard Filter Tips; Cole-Parmer Instrument Company, Niles, Illinois; 1995-96 catalog; pp. 270-271.
Fisherbrand Pipet Tips; Fisher Scientific Company LLC, Pittsburgh, PA; 1993-94 catalog; pp. 1242-1243.
Blaszcak Peter Paul
Spencer Howard Keith
Taggart Thomas
Ludlow Jan
Pennie & Edmonds LLP
Porex Corporation
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