Culture media transfer assembly

Claim 1

In a machine for transferring liquid to a multi-well culture plate having a frame, a support on the frame for a multi-chamber transfer plate which receives the liquid from a source and deposits it in the culture plate, a piston plate having an array of pistons for entering the chambers to draw liquid into and discharge liquid from the chambers, said piston plate and transfer plate being movable with respect to the culture plate, and guide means on the frame for establishing the path of travel of the piston plate; wherein the improvement comprises said guide means for controlling the movement of the piston plate comprising: a rotatable shaft on the frame, a cam on the shaft operatively connected to the piston plate causing the piston plate to follow the cam surface as the cam rotates with the shaft, a handle operatively secured to the shaft for rotating the shaft on the frame to in turn rotate the cam, first detent means on the frame adjacent the shaft, second detent means on the shaft for engaging the first detent means to establish a first reference position for the shaft which represents a starting position for the piston plate with respect to the transfer plate wherein the pistons enter the chambers a limited extent, third detent means movable on the shaft for engaging the first detent means, for establishing a second reference position for the shaft which represents a volume measurement position for the piston plate with respect to the transfer plate wherein the pistons enter the chambers a greater extent than the first position, and means for varying the postion of the third detent means with respect to the shaft for changing the volume measurement postion for the piston plate.

Claim 6

An apparatus for moving a piston plate mounted on a frame between a first reference position and a second reference position, said apparatus comprising: a piston plate mounted on a frame; a rotatable shaft extending horizontally through the frame; means for rotating the shaft; a cam on the shaft operatively connected to the piston plate causing the piston plate to follow the cam surface as the cam rotates with the shaft; a first disc mounted on the shaft and having first detent means on its periphery; a second disc rotatably mounted on the shaft and having second detent means on its periphery; clutch means for releasably engaging the second disc to the shaft so that when said clutch means is disengaged the first and second discs can be rotated with respect to one another in order to establish a relative displacement between said first and second detent means, and when clutch means is engaged said relative displacement is fixed; and third detent means mounted on the frame for engaging either the first or second detent means, wherein, with said clutch means engaged to fix a relative displacement between said first and second detent means, by rotating the shaft the piston plate can be moved from a first reference position where one of said first and second detent means is positioned in the third detent means to a second reference position where the other of said first and second detent means is positioned in the third detent means.

Claim 7

An apparatus for moving a piston plate mounted on a frame between a first reference position and a second reference position, said apparatus comprising: a piston plate mounted on a frame; a rotatable shaft extending horizontally through the frame; means for rotating the shaft; a cam on the shaft operatively connected to the piston plate causing the piston plate to follow the cam surface as the cam rotates with the shaft; a first disc mounted on the shaft and having first detent means on its periphery; a second disc rotatably mounted on the shaft and having second detent means on its periphery; clutch means for releasably engaging the second disc to the shaft so that when said clutch means is disengaged the first and second discs can be rotated with respect to one another in order to establish a relative displacement between said first and second detent means, and when clutch means is engaged said relative displacement is fixed; and third detent means mounted on the frame for engaging either the first or second detent means, wherein, with said clutch means engaged to fix a relative displacement between said first and second detent means, by rotating the shaft the piston plate can be moved from a first reference position where one of said first and second detent means is positioned in the third detent means to a second reference position where the other of said first and second detent means is positioned in the third detent means.