Richard D Thornton

US Patent:

41498089, Apr 17, 1979

Filed:

Sep 14, 1977

Appl. No.:

5/833271

Inventors:

Dan W. Matthias - Downingtown PA
Richard D. Thornton - Concord MA

Assignee:

Exxon Research & Engineering Co. - Florham Park NJ

International Classification:

B41J 1930
B41J 904
H04L 1730

US Classification:

4001442

Abstract:

A serial impact printing element is mounted on the slider of a high performance linear stepper motor. The slider moves through the stator-to-stator air gap of the linear motor stator comprising an active stator portion having windings associated therewith and a passive stator portion without windings. In order to achieve high performance of the motor, the slider is relatively short as compared with the stator, and longitudinal flux leakage through and the weight of the slider are minimized by the use of nonmagnetic discontinuities therein. The impact printing element includes a wheel having a plurality of circumferentially spaced character elements which are rotated to the printing position by means of a rotary stepper motor. Since there are no windings on the passive portion of the stator, the character elements of the wheel are able to pass in close proximity to the passive portion thereby allowing the center of gravity of the rotary motor to be low so as to achieve stability of the impact printing element during high speed operation.

US Patent:

41985826, Apr 15, 1980

Filed:

Jun 24, 1977

Appl. No.:

5/809646

Inventors:

Dan W. Matthias - Downingtown PA
Richard D. Thornton - Concord MA

Assignee:

Exxon Research & Engineering Co. - Florham Park NJ

International Classification:

H02K 4100

US Classification:

310 12

Abstract:

A high performance stepper motor comprises a stator having a plurality of pole positions. Each of the pole positions includes a plurality of stator elements or teeth on opposite sides of a stator-to-stator air gap with nonmagnetic material located in the spaces between the extremities of the teeth. Energization means in the form of a plurality of windings adapted to be connected to a multiphased drive source are associated with the stator means at the various pole positions respectively. Motive means comprising a rotor or a slider includes a plurality of motive elements which comprise teeth or slugs. In order to further achieve low inertia and a high force-to-mass ratio of the passive means, the motive means comprises discontinuities in the magnetic material thereof including nonmagnetic material between the extremities of the motive elements so as to reduce flux leakage in the direction of movement of the passive means through the air gap while simultaneously reducing the mass of the motive means.

US Patent:

45070008, Mar 26, 1985

Filed:

Sep 23, 1983

Appl. No.:

6/534933

Inventors:

Dan W. Matthias - Downingtown PA
Richard D. Thornton - Concord MA

Assignee:

Exxon Research and Engineering Co. - Florham Park NJ

International Classification:

B41J 130

US Classification:

4001442

Abstract:

A print wheel comprising a plurality of character elements for use in a serial impact printer such as a typewriter is directly attached to a rotor of a high performance rotary stepper motor. The rotor which is characterized by a high force-to-mass ratio includes a plurality of circumferentially spaced magnetic drive elements which are integrally formed with the rotor hub which also supports the print wheel. In one embodiment, the stator of the rotary motor forms an axial air gap between an active stator portion and an inactive stator portion, and the rotor and print wheel are removably mounted in the air gap. In another embodiment, the stator of the rotary motor forms a radial air gap between the active stator portion and the inactive stator portion.

US Patent:

42887097, Sep 8, 1981

Filed:

Oct 17, 1979

Appl. No.:

6/085614

Inventors:

Dan W. Matthias - Downingtown PA
Richard D. Thornton - Concord MA

Assignee:

Exxon Research & Engineering Co. - Florham Park NJ

International Classification:

H02K 3700

US Classification:

310 49R

Abstract:

A high performance stepper motor comprises a stator having a plurality of pole positions. Each of the pole positions includes a plurality of stator elements or teeth on opposite sides of a stator-to-stator air gap with nonmagnetic material located in the spaces between the extremities of the teeth. Energization means in the form of a plurality of windings adapted to be connected to a multiphased drive source are associated with the stator means at the various pole positions respectively. Motive means comprising a rotor or a slider includes a plurality of motive elements which comprise teeth or slugs. In order to achieve low inertia and a high force-to-mass ratio, the motive means is located within and confined to the air gap of the stator. The motive elements comprise magnetic material and have extremities juxtaposed to the extremities of the stator elements on both sides of the air gap so as to establish flux paths transverse to the air gap and movement of the motive means relative to the stator means with the resulting force acting on the motive elements at both sides of the air gap. In order to further achieve low inertia and a high force-to-mass ratio of the passive means, the motive means comprises discontinuities in the magnetic material thereof including nonmagnetic material between the extremities of the motive elements so as to reduce flux leakage in the direction of movement of the passive means through the air gap while simultaneously reducing the mass of the motive means.