Abstract: A chamber structure in a blood pump or the like is described. The structure includes a deformable sac having an annular side wall which is held in a rigid condition, and a pair of opposed circular walls, each joined to the annular side wall through a flexible annular wall portion. A circular pusher plate acting against each circular wall has an initial deflection position at which the associated flexible wall portion in the sac takes the form of a circumferentially uniform roll having an outwardly convex, bulged cross sectional curvature. The rolls in the sac maintain their circumferentially uniform, bulge-like character as the pusher plates are moved toward inwardly moved positions.

Abstract: A pump is described in which a flexible enclosure defines a pump chamber whose contents are expelled by movement of a pusher plate engaged with the enclosure. The pusher plate is moved by an elongate beam spring interconnecting the pusher plate with a solenoid drive mechanism. Solenoid actuation causes flexing of the beam spring from a relatively less stressed to a relatively more stressed position, the increased stress in the spring being relieved by pusher element movement. A preferred embodiment of the invention includes a symmetrical arrangement of opposed pusher elements and associated beam springs.

Abstract: A pump is described in which a flexible enclosure defines a pump chamber and in which the contents of the pump chamber are expelled by movement of a pair of opposed pusher elements engaged with the enclosure. The pusher elements are displaced by at least one pair of beam springs, each of which is pivotally supported at one end and is engaged with one of the pusher elements at the other end. The ends of the beam springs opposite the pusher elements are pivoted by actuation of symmetrical solenoid armatures, causing each of the springs to be stressed. Relief of the spring stress forces the pusher elements toward each other. De-energization of the solenoid armatures permits the beam springs to pivot back to the original position upon filling of the pump chamber.