Patent ID: 6959216
Filing Date: 2005-10-25
Classification: A61N

Abstract:
1. An electronic muscle pump comprising: a controller including a sequencer switchable between an on condition and an off condition, the sequencer providing a low level output signal in the on condition and a high level output signal in the off condition; a functional electrical stimulator including an ankle position sensor in electrical communication with the sequencer, the ankle position sensor being adapted for providing a position signal proportional to the position of a foot relative to a leg and selectively switching the sequencer from the off condition to the on condition, and a plurality of electrodes adapted for transmitting the stimulation current to one or more muscles; wherein the controller includes an ankle position threshold generator providing a reference signal and a comparator in electrical communication with the ankle position threshold generator and the ankle position sensor, the comparator comparing the position signal to the reference signal and sending an initiation signal to the sequencer when the position signal and the reference signal are in a predetermined relationship, wherein the ankle position sensor includes a linear potentiometer having a housing adapted for mounting to a patient's leg and a potentiometer shaft adapted for connection to the foot extending from the leg, whereby relative movement between the foot and the leg changes the electrical resistance of the potentiometer, and wherein the ankle position sensor includes a sensing wire and a tension take-up spring, the potentiometer shaft, the sensing wire, and the tension take-up spring each having oppositely disposed first and second ends, the first end of the sensing wire being adapted for mounting to the patient's foot, the first and second ends of the tension take-up spring being mounted to the second end of the sensing wire and the first end of the potentiometer shaft, respectively, and the tension take-up spring absorbing any tension resulting from relative movement between the patient's foot and leg which would urge the potentiometer shaft beyond a mechanical limit of motion.