Browse Prior Art Database

Linear Actuator

IP.com Disclosure Number: IPCOM000097665D
Original Publication Date: 1961-Apr-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 56K

Publishing Venue

IBM

Related People

Anderson, WF: AUTHOR [+3]

Abstract

The electromagnetic linear actuator has an acceleration in excess of 600 times the acceleration of gravity. It also has plane stability within less than +- 25 x 10/-6/ inches over a maximum excursion of one-half inch. The actuator consists of a permanent magnet 1 having a magnetizable core 2 with a circular air gap 3 into which a cylindrical pole piece 4 of the magnet extends. A winding 5 fixed to a hollow magnesium shaft 6 extends between the pole piece 4 and the air gap 3. The shaft 6 and an extension 7 are supported by hydrostatic air bearings 8 and 9.

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Linear Actuator

The electromagnetic linear actuator has an acceleration in excess of 600 times the acceleration of gravity. It also has plane stability within less than +- 25 x 10/-6/ inches over a maximum excursion of one-half inch. The actuator consists of a permanent magnet 1 having a magnetizable core 2 with a circular air gap 3 into which a cylindrical pole piece 4 of the magnet extends. A winding 5 fixed to a hollow magnesium shaft 6 extends between the pole piece 4 and the air gap 3. The shaft 6 and an extension 7 are supported by hydrostatic air bearings 8 and
9.

An alternating current in the frequency range between 10 and 40,000 cycles per second applied to the winding 5 causes winding 5 and shaft 6 to oscillate about an arbitrary center position. A momentary direct current component superimposed upon the A. C. component causes the winding 5 and shaft 6 to shift their center position. The direction depends upon the direction of the direct current. The usual spider for maintaining a center position is not required. A focusing lens or transducer 10 is mounted on the shaft 7. The device is capable of imparting an axial excursion of .5 inches, .25 inches in either direction from an actual center position, to the element 10.

The shaft 6 is prevented from rotating by fins 11. The latter are fixed to the shaft and guided in a hydrostatic air bearing (not shown). This comprises two parallel plates having apertures in their inner surfaces through which air jets a...