US 4,150,921 AGranted

Built-up marine propellers with adjustable pitch and axially removable blades

AssigneePropulsion Systems, Inc.

InventorsPeder K. Wennberg, Mark E. Eastman

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Abstract

Marine propellers are constructed with a split-hub design, permitting adjustment of the pitch of the blades, and axial removability of the blade. By virtue of the axial removability of the blades, blades can be removed easily for repair or replacement without increasing the diametral clearance between the blade tips and a tunnel or nozzle of the type in which propellers are frequently disposed. Also, individual blades can be removed without the necessity of dropping the rudder, which is necessary in many vessels utilizing solid propellers. The blades have their spindles or roots clamped in the hub, such that axial adjustment of pitch can be achieved by reducing the clamping force. The hub preferably is formed in two sections, one section being mounted to or forming part of the propeller shaft, and including recesses which partially house the blade spindles or roots. The other section preferably is made up of a plurality of independently removable clamping segments, each of which is formed with a recess which cooperates with a recess in the first section to house a blade spindle, and clamp the spindle in a fixed blade pitch position. By removal of a selected clamping segment, its blade can be removed axially rearwardly without necessitating substantial diametral clearance at the blade tips. Bolted connections are used between the clamping segments and the first section of the hub so as to facilitate both pitch adjustment and blade removal.

Claims8

Dependent claims

An adjustable pitch marine propeller comprising a hub and a plurality of blades removably mounted in said hub, each of said blades having a mounting root, said hub comprising forward and aft sections, said forward section having a plurality of recesses formed in an aft-facing surface thereof for at least partially receiving said blade roots such that each of said blades is removable from said recesses by axial displacement along an axis at least generally parallel to the longitudinal axis of said hub and is adjustable about its root axis so as to permit pitch adjustment, said aft hub section comprising a plurality of clamping segments formed with recesses therein to cooperate with said recesses in said forward section to form root housings for receiving and frictionally clamping the blade roots when the clamping segments are mounted on said forward hub section, such that pitch-changing rotation of said blade is selectively prevented or permitted by relatively increasing or decreasing the clamping friction between a blade root and its root housing without necessitating rearward movement of the blade, and means for removably mounting and connecting each segment independently on said forward hub section adjacent said aft-facing surface such that the clamping segment recesses mate with the recesses in said forward hub section, and such that each segment is removable or loosenable independently of the other segments such that one blade can be adjusted or removed without affecting the frictional clamping of the blade root of any other blade.

Dependencies are inferred from the claim text.