Liquid transfer pipetting device

Claim 2

In a hand-held pipetter comprising an elongated barrel shaped handle, a piston chamber within said barrel, means at one end of said barrel for holding a disposable tip and for providing fluid communication between said piston chamber and an interior portion of said tip, a piston in said piston chamber, a plunger operably communicating at one end thereof with said piston and extending out of said barrel to a free end thereof through an aperture at another end of the barrel thereby to permit operation of said piston for displacing fluid within said piston chamber by moving the free end of the plunger, and spring means normally urging said piston and plunger toward said another end of the barrel, the improvement comprising: means providing two positive stops of the plunger relative to the barrel shaped handle for selectively limiting travel of the piston with respect to the piston chamber, whereby fluid displacement within the piston chamber is accurately determined by selection of one of said two positive stops for limiting travel of said plunger and piston, a collar on said plunger portion within said barrel handle, a slot oriented with its length extending along a length of said handle, and an adjustable stop carried by and manually movable along the slot to limit the spring return of said plunger collar to a predetermined position engaging the stop, said stop including means operable from outside the handle to fix the stop to the handle at a selected position along the length of said slot.

Claim 3

The improved pipetter according to claim 1 wherein said spring means consists of only one spring.

Claim 4

The improved pipetter according to claim 1 wherein the two positive stops of said selective piston travel limiting means includes first and second calibrated ledges on the plunger portion normally held outside said barrel handle by said spring means, said two positive stops being positioned to engage an outside surface of said another end of said barrel as the plunger is depressed in a manner to operate against said spring means.

Claim 5

The improved pipetter according to claim 3 wherein the aperture at said another end of the barrel and said plunger are of cooperating shape so that when the plunger is pushed against said spring, said first stop hits said another end of the barrel and the plunger can then be released for further movement into the barrel by first moving said plunger laterally with respect to the barrel and then pushing said plunger further into said barrel until the second stop hits said another end of the barrel.

Claim 6

The improved pipetter according to claim 1 wherein the improvement additionally comprises: an adjustment block held by and slidable along the plunger within said barrel handle, said block being selectively tightenable onto said plunger for engaging some portion of said barrel handle interior structure to limit the distance of plunger spring return, said spring means urgiNg said adjusting block toward said another end of said handle, whereby said plunger is urged by the spring only through its connection with said adjusting block, and an opening in the side of said barrel handle adjacent said another end thereof to permit access to said calibrating block for securely fastening it to the plunger.

Claim 7

In a hand-held pipetter comprising an elongated barrel shaped handle, a piston chamber within said barrel, means at one end of said barrel for holding a disposable tip and for providing fluid communication between said piston chamber and an interior portion of said tip, a piston in said piston chamber, a plunger connected at one end thereof with said piston and extending out of said barrel to a free end thereof through an aperture at another end of the barrel thereby to permit operation of said piston for displacing fluid within said piston chamber by moving the free end of the plunger, and spring means normally urging said piston and plunger toward said another end of the barrel, the improvement comprising means providing two positive stops of the plunger relative to the barrel shaped handle for selectively limiting travel of the piston with respect to the piston chamber, whereby fluid displacement within the piston chamber is accurately determined by selection of one of said two positive stops for limiting travel of said plunger said piston, said plunger including a cross-sectional shape in a first portion along its length that fills substantially all of the aperture in said another end of the barrel in at least one direction, a section portion adjacent to said first portion and outward thereof toward the free end of the plunger that is smaller in said one direction than the aperture size in the barrel end member in said at least one direction, a third portion including a first ledge forming one of said positive stops adjacent the second portion of the plunger and extending outward therefrom toward the free end of the plunger with a dimension greater than that of the second section in said at least one direction but still small enough to fit through said aperture of said another end of the barrel handle, a fourth portion immediately adjacent said third portion toward the free end of the plunger and including a second ledge forming the other of said positive stops and having a dimension in excess of the aperture at said another end of the barrel handle in said at least one direction thereby to limit travel of the plunger into the barrel, whereby the small dimension of said second portion permits lateral movement of the plunger with respect to the barrel after said first ledge contacts said another end of the barrel handle.

Claim 8

In a hand-held pipetter comprising an elongated barrel shaped handle, a piston chamber within said barrel, means at one end of said barrel for holding a disposable tip and for providing fluid communication between said piston chamber and an interior portion of said tip, a piston in said piston chamber, a plunger connected at one end thereof with said piston and extending out of said barrel to a free end thereof through an aperture at another end of the barrel thereby to permit operation of said piston for displacing fluid within said piston chamber by moving the free end of the plunger, and spring means normally urging said piston and plunger toward said another end of the barrel, the improvement comprising means providing two positive stops of the plunger relative to the barrel shaped handle for selectively limiting travel of the piston with respect to the piston chamber, whereby fluid displacement within the piston chamber is accurately determined by selection of one of said two positive stops for limiting travel of said plunger said piston, said plunger including a cross-sectional shape in a first portion along its length that fills substantially all of the aperture in said another end of the barrel in at least one direction, a section portion adjacent to said first portion and outward thereof toward the free end of the plunger that is smaller in said one direction than the aperture size in the barrel end member in said at least one direction, a third portion including a first ledge forming one of said positive stops adjacent the second portion of the plunger and extending outward therefrom toward the free end of the plunger with a dimension greater than that of the second section in said at least one direction but still small enough to fit through said aperture of said another end of the barrel handle, a fourth portion immediately adjacent said third portion toward the free end of the plunger and including a second ledge forming the other of said positive stops and having a dimension in excess of the aperture at said another end of the barrel handle in said at least one direction thereby to limit travel of the plunger into the barrel, whereby the small dimension of said second portion permits lateral movement of the plunger with respect to the barrel after said first ledge contacts said another end of the barrel handle.

Claim 9

The improved pipetter according to claim 6 wherein said barrel handle includes a finger hold piece extending outward of said another end thereof and curving to the side and further extending generally in said at least one direction, thereby to permit gripping said barrel handle between the fingers and operating of said plunger with the thumb.

Claim 10

In a hand-held pipetter comprising an elongated barrel shaped handle, a piston chamber within said barrel, means at one end of said barrel for holding a disposable tip and for providing fluid communication between said piston chamber and an interior portion of said tip, a piston in said piston chamber, a plunger connected at one end thereof with said piston and extending out of said barrel to a free end thereof through an aperture at another end of the barrel thereby to permit operation of said piston for displacing fluid within said piston chamber by moving the free end of the plunger, and spring means normally urging said piston and plunger toward said another end of the barrel, the improvement comprising: means providing two positive stops of the plunger relative to the barrel shaped handle for selectively limiting travel of the piston with respect to the piston chamber, whereby fluid displacement within the piston chamber is accurately determined by selection oF one of said two positive stops for limiting travel of said plunger and piston, a collar on said plunger portion within said barrel handle, a stop adjustable along the side of said barrel to limit the return of said plunger by said spring means to a predetermined position, said adjustable stop being located in the interior of said barrel handle and providing an abutment for said collar, a tightening screw threaded to said stop and extending outside of said barrel handle so that the stop and screw are slidable along a slot extending a portion of the length of said barrel for selectively adjusting the stop inside of the barrel, and markings along the one side of the plunger which normally extends outward of said aperture to denote the volume displacement of said piston within said piston chamber, thereby to permit adjustment of said stop for a predetermined volume displacement of said piston.

Claim 11

In a hand-held pipetter comprising an elongated barrel shaped handle, a piston chamber within said barrel, means at one end of said barrel for holding a disposable tip and for providing fluid communication between said piston chamber and an interior portion of said tip, a piston in said piston chamber, a plunger connected at one end thereof with said piston and extending out of said barrel to a free end thereof through an aperture at another end of the barrel thereby to permit operation of said piston for displacing fluid within said piston chamber by moving the free end of the plunger, and spring means normally urging said piston and plunger toward said another end of the barrel, the improvement comprising: means providing two positive stops of the plunger relative to the barrel shaped handle for selectively limiting travel of the piston with respect to the piston chamber, whereby fluid displacement within the piston chamber is accurately determined by selection oF one of said two positive stops for limiting travel of said plunger and piston, a collar on said plunger portion within said barrel handle, a stop adjustable along the side of said barrel to limit the return of said plunger by said spring means to a predetermined position, said adjustable stop being located in the interior of said barrel handle and providing an abutment for said collar, a tightening screw threaded to said stop and extending outside of said barrel handle so that the stop and screw are slidable along a slot extending a portion of the length of said barrel for selectively adjusting the stop inside of the barrel, and markings along the one side of the plunger which normally extends outward of said aperture to denote the volume displacement of said piston within said piston chamber, thereby to permit adjustment of said stop for a predetermined volume displacement of said piston.

Claim 12

In a hand-held pipetter comprising an elongated barrel shaped handle, a piston chamber within said barrel, means at one end of said barrel for holding a disposable tip and for providing fluid communication between said piston chamber and an interior portion of said tip, piston in said piston chamber, a plunger operably communicating at one end thereof with said piston and extending out of said barrel handle to a free end thereof through an aperture at another end of the barrel in a manner to permit operation of said piston for displacing fluid within said piston chamber by moving the free end of the plunger, and spring means normally urging said piston and plunger toward said another end of the barrel handle, the improvement comprising: said spring means normally urging the piston and plunger toward said another end of the barrel including a single strength spring element, a first calibrating ledge extending outward of said plunger and in the vacinity of its free end for striking said another end of said barrel handle adjacent said aperture, and a second calibrating ledge extending outward of said plunger and positioned along its length between its free end and said first calibrating ledge, said second calibrating ledge having dimensions which prohibit further movement of said plunger into the barrel handles when said second calibrating ledge strikes said another end of the barrel handle, the plunger having a dimension immediately adjacent the first calibrating ledge but on its side opposite to that of the second calibrating ledge that is significantly less than the aperture dimension in at least one direction in a manner permitting sufficient lateral movement of the plunger with respect to the barrel handle for movement of the first calibrating ledge through said aperture to permit engagement of the second calibrating ledge with said another end of the barrel handle.

Claim 13

In a hand-held pipetter comprising an elongated barrel shaped handle, a piston chamber within said barrel, means at one end of said barrel for holding a disposable tip and for providing fluid communication between said piston chamber and an interior portion of said tip, piston in said piston chamber, a plunger operably communicating at one end thereof with said piston and extending out of said barrel handle to a free end thereof through an aperture at another end of the barrel in a manner to permit operation of said piston for displacing fluid within said piston chamber by moving the free end of the plunger, and spring means normally urging said piston and plunger toward said another end of the barrel handle, the improvement comprising: said spring means normally urging the piston and plunger toward said another end of the barrel including a single strength spring element, a first calibrating ledge extending outward of said plunger and in the vacinity of its free end for striking said another end of said barrel handle adjacent said aperture, and a second calibrating ledge extending outward of said plunger and positioned along its length between its free end and said first calibrating ledge, said second calibrating ledge having dimensions which prohibit further movement of said plunger into the barrel handles when said second calibrating ledge strikes said another end of the barrel handle, the plunger having a dimension immediately adjacent the first calibrating ledge but on its side opposite to that of the second calibrating ledge that is significantly less than the aperture dimension in at least one direction in a manner permitting sufficient lateral movement of the plunger with respect to the barrel handle for movement of the first calibrating ledge through said aperture to permit engagement of the second calibrating ledge with said another end of the barrel handle.

Claim 14

The improved hand-held pipetter of claim 9 which additionally comprises adjustable means within said barrel defining an extreme return position of said plunger and piston toward said barrel another end, whereby, a stroke distance of said plunger from said extreme return position to its depressed position wherein the first calibrating ledge strikes said barrel another end is variable while a stroke distance of said plunger as it is depressed between its said first and second calibrated ledges is fixed.

Claim 15

In a hand-held pipetter comprising an elongated hollow handle, a piston chamber within said handle means at one end of said handle for holding a disposable tip and for providing fluid communication between said piston chamber and an interior portion of said tip, a piston in said piston chamber, a plunger operably connected at one end thereof with said piston and extending out of said handle at another end thereof, thereby to permit operation of said piston for displacing fluid within said piston chamber by moving the plunger, and spring means normally urging said piston and plunger toward said another end of the handle, the improvement comprising: a collar rigidlY attached to said plunger along a portion thereof within said barrel handle, a slot oriented with its length extending along a length of said handle, and an adjustable stop carried by and manually movable along the slot to limit the spring return of said plunger to a predetermined position engaging the stop, said stop including means operable from outside the handle to fix the stop to the handle at a selected position along the length of said slot.

Claim 16

In a hand-held pipetter comprising an elongated hollow handle, a piston chamber within said handle means at one end of said handle for holding a disposable tip and for providing fluid communication between said piston chamber and an interior portion of said tip, a piston in said piston chamber, a plunger operably connected at one end thereof with said piston and extending out of said handle at another end thereof, thereby to permit operation of said piston for displacing fluid within said piston chamber by moving the plunger, and spring means normally urging said piston and plunger toward said another end of the handle, the improvement comprising: a collar rigidlY attached to said plunger along a portion thereof within said barrel handle, a slot oriented with its length extending along a length of said handle, and an adjustable stop carried by and manually movable along the slot to limit the spring return of said plunger to a predetermined position engaging the stop, said stop including means operable from outside the handle to fix the stop to the handle at a selected position along the length of said slot.

Claim 17

In a hand-held pipetter comprising an elongated hollow handle, a piston chamber within said handle, means at one end of said handle for holding a disposable tip and for providing fluid communication between said piston chamber and an interior portion of said tip, a piston in said piston chamber, a plunger operably connected at one end thereof with said piston and extending out of said handle at another end thereof, thereby to permit operation of said piston for displacing fluid within said piston chamber by moving the plunger, and spring means normally urging said piston and plunger toward said another end of the handle, the improvement comprising: a collar rigidly attached to said plunger along a portion thereof within said barrel handle, an adjustable stop located in the interior of said handle to limit the return of said plunger by said spring means to a predetermined position upon engagement of said collar with said stop, a tightening screw threaded to said stop and extending outside of said handle, the stop and screw being slidable along a slot extending a portion of the length of said handle for selectively adjusting the stop inside of the barrel, and markings along the one side of the plunger which normally extend outward of said handle to denote the volume displacement of said piston within said piston chamber, thereby to permit adjustment of said stop for a predetermined volume displacement of said piston.

Claim 18

In a hand-held pipetter comprising an elongated hollow handle, a piston chamber within said handle, means at one end of said handle for holding a disposable tip and for providing fluid communication between said piston chamber and an interior portion of said tip, a piston in said piston chamber, a plunger operably connected at one end thereof with said piston and extending out of said handle at another end thereof, thereby to permit operation of said piston for displacing fluid within said piston chamber by moving the plunger, and spring means normally urging said piston and plunger toward said another end of the handle, the improvement comprising: a collar rigidly attached to said plunger along a portion thereof within said barrel handle, an adjustable stop located in the interior of said handle to limit the return of said plunger by said spring means to a predetermined position upon engagement of said collar with said stop, a tightening screw threaded to said stop and extending outside of said handle, the stop and screw being slidable along a slot extending a portion of the length of said handle for selectively adjusting the stop inside of the barrel, and markings along the one side of the plunger which normally extend outward of said handle to denote the volume displacement of said piston within said piston chamber, thereby to permit adjustment of said stop for a predetermined volume displacement of said piston.

Claim 19

In a hand-held pipetter comprising an elongated hollow handle, a piston chamber within said handle, means at one end of said handle for holding a disposable tip and for providing fluid communication between said piston chamber and an interior portion of said tip, a piston in said piston chamber, a plunger operably connected at one end thereof with said piston and extending out of said handle at another end thereof, thereby to permit operation of said piston for displacing fluid within said piston chamber by moving the plunger, and spring means normally urging said piston and plunger toward said another end of the handle, the improvement comprising: a calibrating block held by and slidable along the plunger within said handle, said block being selectively tightenable onto said plunger for engaging a portion of the handle''s interior structure to limit the distance of the plunger spring return, said spring means urging said adjusting block toward said another end of said handle, whereby said plunger is urged by the spring only through its connection with said adjusting block, and an opening in the side of said barrel handle adjacent said another end thereof to permit access to said calibrating block for securely fastening it to the plunger.

Claim 20

In a hand-held pipetter comprising an elongated hollow handle, a piston chamber within said handle, means at one end of said handle for holding a disposable tip and for providing fluid communication between said piston chamber and an interior portion of said tip, a piston in said piston chamber, a plunger operably connected at one end thereof with said piston and extending out of said handle at another end thereof, thereby to permit operation of said piston for displacing fluid within said piston chamber by moving the plunger, and spring means normally urging said piston and plunger toward said another end of the handle, the improvement comprising: a calibrating block held by and slidable along the plunger within said handle, said block being selectively tightenable onto said plunger for engaging a portion of the handle''s interior structure to limit the distance of the plunger spring return, said spring means urging said adjusting block toward said another end of said handle, whereby said plunger is urged by the spring only through its connection with said adjusting block, and an opening in the side of said barrel handle adjacent said another end thereof to permit access to said calibrating block for securely fastening it to the plunger.

Claim 21

In a hand-held pipetter comprising an elongated barrel shaped handle, a piston chamber within said barrel, means at one end of said barrel for holding a disposable tip and for providing fluid communication between said piston chamber and an interior portion of said tip, a piston in said piston chamber, a plunger operably communicating at one end thereof with said piston and extending out of said barrel handle to a free end thereof through an aperture at another end of the barrel in a manner to permit operation of said piston for displacing fluid within said piston chamber by moving the free end of the plunger, and spring means normally urging said piston and plunger toward said another end of the barrel handle, the improvement comprising: said spring means normally urging the piston and plunger toward said anothEr end of the barrel including a single strength spring element, a single finger hold attached to the barrel adjacent said another end thereof and extending outward of a side of the barrel in one direction, a first calibrating ledge extending outward of said plunger in said one direction and in the vacinity of its free end for striking another end of said barrel handle adjacent said aperture, a second calibrating ledge extending outward of said plunger in said one direction and positioned along its length between its free end and said first calibrating ledge, said second calibrating ledge having dimensions with prohibit further movement of said plunger into the barrel handle when said second calibrating ledge strikes said another end of the barrel handle, the plunger having a dimension immediately adjacent the first calibrating ledge but on its side opposite to that of the second calibrating ledge that is significantly less than the aperture dimension in said one direction in a manner permitting sufficient lateral movement of the plunger with respect to the barrel handle in a direction away from said finger hold to permit movement of the first calibrating ledge through said aperture to permit engagement of the second calibrating ledge with said another end of the barrel handle, a collar on said plunger portion within said barrel handle, a slot oriented with its length extending along a length of said handle, and an adjustable stop carried by and manually movable along the handle slot to limit the spring return of said plunger collar to the predetermined position engaging the stop, said stop including means operably from outside the handle to fix the stop to the handle at a selected position along the length of said slot.

Claim 22

In a hand-held pipetter comprising an elongated barrel shaped handle, a piston chamber within said barrel, means at one end of said barrel for holding a disposable tip and for providing fluid communication between said piston chamber and an interior portion of said tip, a piston in said piston chamber, a plunger operably communicating at one end thereof with said piston and extending out of said barrel handle to a free end thereof through an aperture at another end of the barrel in a manner to permit operation of said piston for displacing fluid within said piston chamber by moving the free end of the plunger, and spring means normally urging said piston and plunger toward said another end of the barrel handle, the improvement comprising: said spring means normally urging the piston and plunger toward said anothEr end of the barrel including a single strength spring element, a single finger hold attached to the barrel adjacent said another end thereof and extending outward of a side of the barrel in one direction, a first calibrating ledge extending outward of said plunger in said one direction and in the vacinity of its free end for striking another end of said barrel handle adjacent said aperture, a second calibrating ledge extending outward of said plunger in said one direction and positioned along its length between its free end and said first calibrating ledge, said second calibrating ledge having dimensions with prohibit further movement of said plunger into the barrel handle when said second calibrating ledge strikes said another end of the barrel handle, the plunger having a dimension immediately adjacent the first calibrating ledge but on its side opposite to that of the second calibrating ledge that is significantly less than the aperture dimension in said one direction in a manner permitting sufficient lateral movement of the plunger with respect to the barrel handle in a direction away from said finger hold to permit movement of the first calibrating ledge through said aperture to permit engagement of the second calibrating ledge with said another end of the barrel handle, a collar on said plunger portion within said barrel handle, a slot oriented with its length extending along a length of said handle, and an adjustable stop carried by and manually movable along the handle slot to limit the spring return of said plunger collar to the predetermined position engaging the stop, said stop including means operably from outside the handle to fix the stop to the handle at a selected position along the length of said slot.

Claim 23

The improved pipetter according to claim 14 wherein the improvement additionally comprises markings on one side of the plunger along a length thereof adjacent said free end to denote the volume displacement of said piston within said piston chamber, whereby the volume displacement of the pipetter may be set with reference to said markings.