Brunswick Corporation

Daniel R Lindgren

Michael A Karls

A marine drive having a drive sleeve and a drive sleeve adapter between the propeller shaft and the propeller hub where the drive sleeve absorbs the shock of the propeller striking an object by torsionally twisting a forward end of the drive sleeve which is keyed to the propeller hub and where the adapter is keyed to the propeller shaft and the drive sleeve is keyed to the adapter. The combination provides both high load capability and shock protection.

Torsionally twisting propeller drive sleeve and adapter

In a marine drive (10), a drive sleeve (50) between the propeller shaft (22) and the propeller hub (34) absorbs shock after the propeller (12) strikes an object by torsionally twisting between a forward end keyed to the propeller hub and a rearward end keyed to the propeller shaft. The drive sleeve is composed of a plastic material providing torsional twisting angular rotation at a first spring rate less than 100 lb. ft. per degree from 0.degree. to 5.degree. rotation, a second higher spring rate beyond 5.degree. rotation, and supporting over 1,000 lb. ft. torque before failure.

Torsionally twisting propeller drive sleeve

A shock absorbing drive sleeve (50) is provided by a molded plastic member directly mounting the propeller hub (14) to the propeller shaft (22). The sleeve has a rearward inner diameter portion (52) engaging the propeller shaft in splined relation, and a forward inner diameter portion (56) spaced radially outwardly of and disengaged from the propeller shaft. The drive sleeve has a rearward outer diameter portion (58), and a forward outer diameter portion (60) engaging the propeller hub. The drive sleeve and the propeller hub are tapered relative to each other such that a forward outer diameter portion (60) of the drive sleeve snugly engages the propeller hub, and a rearward outer diameter portion (58) is spaced slightly radially inwardly of the hub by a small gap (62) and may partially rotate relative to the propeller hub in response to rotation of the propeller shaft drivingly engaging the rearward inner diameter portion. When the propeller strikes an object, the shock is absorbed by torsional twisting of the drive sleeve wherein the rearward inner diameter portion and the rearward outer diameter portion continue to rotate to a further rotated position than the forward outer diameter portion, whereafter the splined teeth of the rearward inner diameter portion shear.

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Fond du Lac, WI, United States of America

Daniel R Lindgren