Push-pull linear motor

Claim 1

An improved drive means to shift an axially shiftable member forwardly and rearwardly to and from a central normal position comprising an elongate armature shaft with front and rear ends, coupling means connecting the front end of the shaft with the member, a pair of front and rear armatures on the shaft in spaced relationship and defining forwardly and rearwardly, axially and radially outwardly disposed conical surfaces, front and rear electro magnet field units arranged forwardly and rearwardly of the front and rear armatures and having axially and radially inwardly disposed conical north and south poles in normal predetermined spaced and opposing relationship with the conical surfaces of the armatures, resilient support means at the ends of the shaft maintaining the shaft on a common axis and biased to exert equal and opposing forces axially inwardly at the ends of the shaft and normally yieldingly holding the shaft with the armature in its normal position, said field units normally energized by quiescent currents and establishing equal and opposite magnetic fields intersecting the armatures related thereto whereby the armatures are normally magnetized and held in their normal position by the fields, said armatures and shaft being shifted axially toward one field unit upon an increase of current thereto and a decrease of current to the other field unit resulting in increase and decrease in the magnetic fields of the units acting on their related armatures, the armatures having progressively magnetically saturable portions whereby the saturable portion of the armatures saturate progressively upon linear longitudinal movement toward their related field units and in response to linear differentials in the currents to the field units.