Marine propeller lock

Claim 1

A locking device for marine propellers to prevent their removal from a power drive shaft of a marine engine, the device comprising: (a) retaining means mounted on said drive shaft for securing the propeller to the drive shaft, said retaining means having an elongated cylindrical outer surface arranged coaxially with said drive shaft; (b) cover means slidably mounted over said retaining means, said cover means being generally elongated and sized to surround and loosely fit over said retaining means to restrict access to and prevent unauthorized removal of the retaining means and propeller, the outer surface of said cover means being formed in a generally continuous curve and having no more than one flat surface to prevent a person or object from gripping and forcibly turning the cover in order to apply a removal force to the retaining means; (c) said cover means having a central axis and a first cylindrical recess arranged coaxially with said central axis and extending inwardly from one end, said recess being sized to loosely fit the retaining means to allow the cover means to rotate with respect to said retaining means; (d) said cover means further including a second cylindrical recess arranged coaxially with said central axis and extending inwardly from the opposite end of said cover means from said first recess, the interior ends of said first and second recesses being spaced apart so as to form a partition therebetween; (e) bolt means mounted through an aperture in said partition to secure said cover means to said retaining means, said bolt means having a head and an enlarged shank forming a shoulder which has a longitudinal dimension between the head and shoulder which is slightly greater than the thickness of said partition whereby when said bolt means is tightened to said retaining means the cover means will remain free to turn without applying a turning force to the bolt means; (f) cap means mounted in the end of the second recess of said cover means and sized to engagingly fit and close said second recess; and (g) wrench means having a gripping area at one end and a plurality of socket ridges having a non-standard pattern formed at the opposite end, said head of the bolt means having a plurality of recessed grooves formed therein which corresponds to the pattern formed by the socket ridges of said wrench means whereby only the corresponding wrench means can be used to install or remove said bolt means.