The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 13, 1994
Filed:
Mar. 10, 1993
David W Barrett, East Hartland, CT (US);
Richard E Peruggi, Glastonbury, CT (US);
Louis Bialy, Simsbury, CT (US);
Ernest P Gagnon, Manchester, CT (US);
Otis Elevator Company, Farmington, CT (US);
Abstract
A linear motor is used to actuate an elevator door in response to a control signal for counteracting rotational torque caused by a variable-length moment arm about the center of gravity of the door by varying the magnitude of a linear force exerted on the door acting through a fixed-length moment arm about the center of gravity of the door for providing an opposing rotational torque, thereby counteracting the rotational torque caused by the normal force. The first and second rotational torques may be controlled to decrease and increase linearly as the door goes through its motion. In this way, the velocity profile varies in a curve similar to one side of the major axis of an ellipse. The normal force may be provided so as to levitate the door to reduce gravitational forces acting on door rollers. The control may be carried out in an open- or closed-loop fashion.