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:
Jan. 31, 1989
Filed:
Nov. 03, 1987
John A Norton, Norwell, MA (US);
Bird-Johnson Company, Walpole, MA (US);
Abstract
An adjustable diameter screw propeller includes a hub having a plurality of spindles, each mounted in the hub for rotation about an axis disposed radially of the hub axis and a mechanism for synchronously turning the spindles in a common direction. A plurality of propeller blades having a fixed pitch contour and a skew in the range of 60.degree. to 90.degree. are attached to respective ones of the spindles, such that as the spindles are turned, the blades rotate between a first disposition in which the diameter of the propeller is maximum and a second disposition in which the diameter of the propeller is reduced. In addition, the pitch of the propeller increases as the propeller diameter decreases to compensate for the loss of power that would otherwise occur as the propeller diameter is decreased.