Patent ID: 6871759

Claim:
An ambulatory infusion pump for expelling fluid from a fluid reservoir bag, comprising: a generally rectangular housing defining a longitudinal central axis, said housing having an interior space therein; a first wall within said interior space defining a first surface for contacting said fluid reservoir bag; a second wall within said interior space defining a second surface for contacting said fluid reservoir bag, said second surface facing said first surface, said second wall being moveable between a first position and a second position relative to said first wall, said second position being closer than said first position; an elongated first guide rod and an elongated second guide rod spaced from said central axis on opposing sides thereof, said first and second guide rods being oriented generally parallel to said central axis; a first moveable stop and a second moveable stop, each of said first and second movable stops being slideably engaged with each of said first and second guide rods; at least one parallelogram linkage assembly having first and second opposing pivots connected to said housing and said second wall, respectively, and third and fourth opposing pivots connected to said first and second moveable stops, respectively; and at least one spring configured apply a force tending to bias said first and second stops toward one another, thereby moving said third and fourth pivots toward one another and moving said first and second pivots away from one another to move said second wall toward said second position.