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. 25, 1990
Filed:
Apr. 18, 1990
David N AbuJudom, II, Brookfield, WI (US);
Paul E Thoma, Wauwatosa, WI (US);
Roger V Hajny, Cedarburg, WI (US);
Steven A Linstead, North Prairie, WI (US);
Johnson Service Company, Milwaukee, WI (US);
Abstract
A shape memory actuator for controlling the position of a control member, such as a damper plate in a duct, the actuator including first and second shape memory elements each having an austenite phase transition temperature above which each element assumes a predetermined memory shape and a lower phase which forms when said element is stretched from the predetermined memory shape, the first and second elements being connected to move the control member in different directions when one or the other of the elements are heated to a temperature above its austenite phase transition temperature and an electrical circuit for selectively raising the temperature of one or the other of the elements. The control member may be held in a position between full open and full closed by holding mechanisms which connect the actuator to the control member. The holding mechanisms include a visco elastic mechanism, a positive interlock mechanism that is released by a shape memory element, or a magnetic member formed of alternately arranged magnetic poles. A number of connectors are disclosed for connecting the SMA members to the dampers.