Disposable Pipette Tip

A disposable pipette tip for use with a pipetting system having a tip mounting shaft that includes a locking section having a stop, two or more outwardly extending lobes located above the stop and spaced circumferentially around the locking section of the mounting shaft, and recessed relief portions spanning circumferentially between the lobes and recessed relative to the lobes, each respective lobe having a catch surface that is spaced longitudinally from the stop on the mounting shaft by a predetermined distance, said disposable pipette tip comprising:

• a barrel having a lower opening through which liquid is aspirated into the barrel and dispensed from the barrel;
• a collar having a upper opening for receiving the tip mounting shaft, the lower end of the collar having an inside diameter that is larger than the inside diameter of the upper end of the barrel;
• a circumferential shelf connecting the lower end of the collar to the upper end of the barrel;
• and
• means for engaging the catch surfaces on the respective locking lobes when the disposable pipette tip is mounted on the tip mounting shaft with the circumferential shelf of the tip engaging the stop on the mounting shaft;
• wherein the collar of the disposable pipette tip is sufficiently flexible to distort outwardly at the lobes on the mounting shaft and inwardly at the recessed relief portions on the mounting shaft between the lobes when the pipette tip is mounted on the tip mounting shaft.

A disposable pipette tip for use with the pipetting system having a tip mounting shaft with a locking section including a stop, two or more outwardly extending lobes spaced circumferentially around the locking section of the mounting shaft and located above the stop on the mounting shaft and recessed relief portions spanning circumferentially between the lobes and recessed relative to the lobes, each respective lobe having a catch surface that is spaced longitudinally from the stop on the mounting shaft by a predetermined distance, said disposable pipette tip comprising:

• a barrel having a lower opening through which liquid is aspirated into the barrel and dispensed from the barrel;
• a collar having an upper opening for receiving the tip mounting shaft, the lower end of the collar having an inside diameter that is larger than the inside diameter of the upper end of the barrel;
• a circumferential shelf connecting the lower end of the collar to the upper end of the barrel;
• and
• a substantially circumferential locking element extending inward from the inside surface of the collar and located below a rim of the upper opening of the collar and above the circumferential shelf at a longitudinal distance above the circumferential shelf substantially equal to said first predetermined distance;
• wherein, when the disposable pipette tip is fully mounted on the tip mounting shaft, the circumferential shelf engages the stop on the tip mounting shaft and the substantially circumferential locking element on the collar engages the respective catch surfaces on the circumferentially spaced outwardly extending lobes on the mounting shaft such that the collar distorts outwardly at the lobes and inwardly at the recessed relief portions on the mounting shaft between the lobes;
• and further wherein the collar of the disposable pipette tip is sufficiently flexible to distort outwardly at the lobes on the mounting shaft and inwardly at the recessed relief portions on the mounting shaft between the lobes when the pipette tip is mounted on the tip mounting shaft.

A disposable pipette tip for use with a pipetting system having a tip mounting shaft with a lower sealing section and an upper locking section, the upper locking section including a stop, two or more outwardly extending lobes spaced circumferentially around the locking section of the mounting shaft and located above the stop on the mounting shaft, and recessed relief portions spanning circumferentially between the lobes and recessed relative to the lobes, the lower sealing section of the tip mounting shaft having a diameter less than the diameter of a portion of the upper locking section immediately adjacent the stop, said disposable pipette tip comprising:

• a barrel having a lower opening through which liquid is aspirated into the barrel and dispensed from the barrel;
• a collar having an upper opening for receiving the tip mounting shaft, the lower end of the collar having an inside diameter that is larger than the inside diameter of the upper end of the barrel;
• a circumferential shelf connecting the lower end of the collar to the upper end of the barrel;
• and
• means on the barrel below the circumferential shelf for sealing the pipette tip against the lower sealing section of the tip mounting shaft when the disposable pipette tip is mounted on the tip mounting shaft;
• wherein the collar of the disposable pipette tip is sufficiently flexible to distort outwardly at the lobes on the mounting shaft and inwardly at the recessed relief portions on the mounting shaft between the lobes when the pipette tip is mounted on the tip mounting shaft.

A disposable pipette tip for use with a pipetting system having a tip mounting shaft with a lower sealing section and upper locking section, the upper locking section including a stop, two or more outwardly extending lobes spaced circumferentially around the locking section of the mounting shaft and located above the stop on the mounting shaft, and recessed relief portions spanning circumferentially between the lobes and recessed relative to the lobes, the lower sealing section of the tip mounting shaft having a diameter less than the diameter of the portion of the upper locking section immediately adjacent to the stop, said disposable pipette tip comprising:

• a barrel having a lower opening through which liquid is aspirated into the barrel and dispensed from the barrel, the inside surface of an upper portion of the pipette tip barrel including a circumferential ring encircling the inside surface of the pipette tip and extending inward from the inside surface of the barrel;
• a collar having an upper opening for receiving the tip mounting shaft, the lower end of the collar having an inside diameter that is larger than the inside diameter of the upper end of the barrel;
• and
• a circumferential shelf connecting the lower end of the collar to the upper end of the barrel, the circumferential ring of the pipette tip barrel being located below the circumferential shelf;
• wherein, when the disposable pipette tip is fully mounted to the mounting shaft, the circumferential shelf engages the stop on the tip mounting shaft and the collar engages the circumferentially spaced outwardly extending lobes on the mounting shaft above the stop such that the collar distorts outwardly at the lobes and inwardly at the recessed relief portions on the mounting shaft between the lobes, and the circumferential ring at the upper end of the tip barrel engages the lower sealing section of the tip mounting shaft.