Patent ID: 7083068

Claim:
An infusion pump for expelling fluid from a fluid bag having an outlet, comprising: a base having a bag-engaging inner surface for supporting said fluid bag, said base having a substantially continuous side wall extending away from said bag-engaging inner surface, said side wall having a port configured to accommodate a fluid delivery tube of said bag; a cover cooperating with said base to define a space in which said bag may be positioned, said cover configured such that it may be selectively connected to said base; a pressure plate movably connected to said cover and moveable from a first position in which a bag-engaging surface of said pressure plate is located a first distance above said inner surface of said base to a second position in which said bag-engaging surface of said pressure plate is located a second distance nearer said inner surface of said base than said first distance, said bag-engaging surface of said pressure plate being complementary to said bag-engaging inner surface of said base, said pressure plate connected to said cover by an assembly comprising a linkage, a shaft having a first end and a second end, a pair of slides movable along said first and second shafts, and a spring mounted between each of said ends of said shaft and said slides, said linkage having a parallelogram shape formed by four arms, said arms rotatably connected to said slides and rotatably connected to said pressure plate and said cover; and a fluid level indicator arrangement comprising a view window within said side wall of said base and encompassing both said first and second positions of said pressure plate such that a fluid level within said fluid bag may be determined from external said infusion pump.