Pulsatile blood pump

A pulsatile blood pump comprising a hermetically sealed housing, a disposable, substantially enclosed sac of anticoagulative material mounted in said housing, at least one portion of said sac being formed of highly flexible material, said sac being provided with a suction port having an inlet check valve and a delivery port having an outlet check valve to constitute a closed pump unit, said suction and delivery ports extending outwardly of said housing, a pressure transmissive fluid means located within said housing surrounding at least in part said highly flexible wall of said sac and drive means for generating a pulsatile pressure in said transmissive fluid to flex said highly flexible wall producing a pumping action in said sac having a delivery stroke and a suction stroke, said drive means comprising a cam mechanism including a disc rotatable about a central axis by said drive means and provided with an eccentric channel means for rotating said disc about a central axis, and means for converting the rotary motion of said disc into reciprocating motion comprising a follower member, a stroke control means connected to said follower member, a connecting rod and a piston communicating with said transmissive fluid, and torque reduction means adapted to render said suction and delivery stroke uniform, said torque reduction means including a rocking lever on which said follower member is mounted pivoted at one end to a fixed base member and engaging at its opposite end the eccentric channel and a resilient plunger fixedly secured within a cylinder having a connecting rod attached to said rocking lever.