Patent ID: 7581995
Filing Date: 2009-09-01
Classification: B63H

Abstract:
1. In an apparatus that cuts foreign matter including lines, wires, nets and weeds that may be encountered by propeller driven vessels when under way, said vessels where the propeller is mounted to a rotatable propeller shaft that extends from a propeller shaft housing connected to the vessel's hull, and in which there is axial movement of said propeller shaft, said apparatus having: at least one first blade having a first shearing plane, said first blade arranged to rotate in conjunction with said propeller with said first shearing plane substantially perpendicular to the shaft axis; a first support adapted to support said first blade in a position extending radially beyond said first support to engage said foreign matter, said first support adapted to fixedly attach to at least one member of the pair consisting of said shaft and said propeller; at least one second blade having a second shearing plane, said second blade arranged with said second shearing plane substantially parallel to said first shearing plane; a second support adapted to support said second blade in a position extending radially parallel to said first blade to engage said foreign matter for shearing said foreign matter between said first and second blades, said second support including attaching means for fixedly attaching to a non-rotating member of said hull; said first blade and said second blade each having radially extending shearing edges on at least one margin of said shearing planes for cutting said foreign matter when said propeller rotates; said second support arranged to provide limited axial movement of second blade with adjustable clamping means for limiting movement of said second blade with adjustable tension, said clamping means including elastic bias members for maintaining said adjustable tension; a combination of a slot and a slot follower for regulating the axial position of said second blade, one of said combination of said slot and said slot follower connected to said first blade and the other connected to said second blade, each arranged in a plane perpendicular to said axis of said propeller shaft and extending through an arc so that said slot follower fits within said slot during a fraction of each rotation of said shaft to regulate the axial position of said second blade for close approximation of said first and second shearing planes for enhanced shearing action between said blades, said second support providing limited pivotal movement of said second blade; a combination of a wedge and a valley for interacting to apply axial force to move said second blade toward said first blade when said second blade pivots in said second support; one of said combination of said wedge and said valley is connected to said second blade and the other is connected to said second support, and said limited pivotal movement is generated by said foreign matter interposed between said first and second blades during propeller rotation, wherein the improvement in the apparatus comprises: a) said second support having an elongate, axially disposed cylindrical passage that holds a cylindrical member affixed to the second blade adapted for limited movement of the blade as the cylindrical member reciprocates within the passage, the passage provided with a lubricant seal at a forward end thereof and a lubricant seal at an aft end thereof for retention of lubricant within said passage; b) said adjustable clamping means for limiting movement of said second blade including said elastic bias members applying tension between the cylindrical member and the passage to limit motion therebetween, the elastic bias members being enclosed within rigid elements including a piston sliding within an enclosing sleeve to prevent deformation of the elastic bias members over time; c) said attaching means for fixedly attaching said second support means to a non-rotating member of said hull comprising a rigid metal member for affixing to the hull, the rigid metal member having a first surface adapted for receiving thereon at least one alignment screw member threadedly engaged by said second support, the first surface provided with at least two threaded apertures for receiving threaded fasteners from said second support for removably affixing the metal member to said second support after said at least one alignment screw member has been adjusted to maintain said second shearing plane parallel to said first shearing plane.