Patent ID: 7569049

Claim:
A method of operating an implantable drug pump system, the implantable drug pump system comprising (i) a battery for powering the implantable drug pump system, (ii) a valve assembly to control a flow of infusate from the implantable drug pump into the patient's system, (iii) a cantilever arm that is physically coupled to the valve assembly, the cantilever arm being physically adapted to return without consumption of power to a stable first state after application of force to the cantilever arm to move the cantilever arm along a first direction, wherein the cantilever arm comprises first and second opposing longitudinal portions with a distal end of the cantilever arm extending past the valve assembly along a second direction that is generally perpendicular to the first direction, (iv) an actuator for applying force to the cantilever arm to move the cantilever arm along the first direction, and (v) a moveable physical stop that is moveable along the second direction, the method comprising: (a) moving the physical stop along the second direction to move the physical stop past the distal end of the cantilever arm to permit movement of the cantilever arm along the first direction; (b) applying power to the actuator to move the cantilever arm along the first direction past the physical stop to cause the valve assembly to change flow states from a first flow state to a second flow state; (c) moving the physical stop along the second direction to move the physical stop inside the distal end of the cantilever arm after the cantilever is positioned past the physical stop and while power is applied to the actuator; (d) ceasing to apply power to the actuator to permit the cantilever arm to move along the first direction towards the first stable state; (e) contacting the distal end of the cantilever arm against the physical stop to prevent the cantilever arm from reaching the first stable state, wherein the contacting causes the cantilever arm to rest against the physical stop in a second stable state without consuming power from the battery and the valve assembly remains in the second flow state.