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:
Nov. 05, 1996
Filed:
Jul. 17, 1995
Charles W Pratt, Estes Park, CO (US);
Other;
Abstract
Windmill (10) having a plurality of hydrodynamic, folding blades (12, 14, 16 and 18) secured to a hub (64). The blades are propelled by wind current such that the windmill rotates about a central axis of a shaft (20) on which a hub (64) is journalled. Each folding blade extends radially from the hub and includes a lower blade portion (24) attached to the hub and an upper blade portion (22) pivotally attached to the lower blade portion. The lower blade portion includes a hydrodynamic surface extending from a first edge(43) and terminating at a trailing edge (42). The upper blade portion is hydrodynamically contoured so as to form a nose cone (44). An apex of the nose cone forms a leading edge (40) of the upper blade portion that is opposite a trailing edge (41). The nose cone is weighted such that the trailing edge of the upper blade portion balances in a position slightly separate from the trailing edge of the lower blade portion when the fluid current fails to flow at a speed that exceeds a minimum threshold. However, when the fluid current impinges the trailing edge of the upper blade portion and the fluid current flows at a speed that exceeds a minimum threshold, the weighted nose cone of the upper blade portion causes the upper blade portion to pivot away from the lower blade portion so that the trailing edge of the upper blade portion is separated from the trailing edge of the lower blade portion at an acute angle. Accordingly, when the fluid current ceases to impinge the trailing edge of the upper blade portion, the weighted nose cone of the upper blade portion causes the upper blade portion to pivot toward the lower blade portion such that the trailing edge of the upper blade portion approaches the trailing edge of the lower blade portion.