Abstract: In a machine for edge welding magnetically permeable work pieces, e.g. ar plate, the improvement comprising probe means for centering the torch on the centerline of the gap between the work pieces. The probe also provides an electric signal representing the path taken by the torch along the gap joint. The signal can be used to program the machine for successive multiple passes over the gap joint.

Abstract: The present invention is a concept to provide a means of movement control for a powered prosthetic device. An externally detectable article is implanted on a biological site where the exertion of muscle tension will impart a movement of the article. The muscle can be attached to an antagonistic natural muscle or some means of exerting an opposing tension on the natural muscle. The recipient controlled tension in the appropriate muscle moves the externally detectable article and an external detector monitors that movement and generates control signals to the means powering the device in relation to the amount and direction of movement of the implanted article.