Roller clamp for defining a flow lumen in tubing

Claim 1

In a roller clamp for controlling fluid flow through flexible tubing, the clamp having an elongated U-shaped body with rigid opposite upstanding walls joined by a base, a cylindrical roller having an axle mounted at its opposite ends in tracks formed in the walls, the tracks having axle bearing surfaces extending coplanar with one another and parallel to said base, the improvement comprising: a roller bearing surface in said base spaced uniformly below the axle bearing surfaces of the track a distance to obtain a biased fit between the roller and roller bearing surface by the axle snugly engaging the axle bearing surface on the body to substantially prevent movement of the roller perpendicular to said base and to permit only longitudinal movement of the roller upon application of a manual force to the roller in a direction along the body; surfaces forming a tube-compression slot in said base including a lower wall spaced uniformly below the level of said roller bearing surface along the body, the tube-compression slot having at least one shoulder joining the lower wall of the slot to the roller bearing surface; surfaces forming a channel in the lower wall of the tube-compression slot, the channel receiving a portion of the tubing to form a controlled lumen having a cross-sectional configuration substantially the same as that of the cross-sectional configuration of the channel; and said channel further having a cross-sectional area which varies progressively from one position along the base to another in the direction of said longitudinal movement, thereby enabling adjustment of liquid flow through the lumen of the tubing confined within the tube-compression slot and said channel depending on the position of the roller along the body, from the large flow to no flow, substantially without unintended perpendicular movement of the roller along the body and with minimal change in flow over time at any selected position of the roller.