This invention relates to a propulsion unit for an inboard-outboard motor and more particularly to an improved propulsion unit that lends itself to reversal of the rotation of the propulsion device in a simple and expedient manner for twin outboard drive arrangements.
It is well known that a marine outboard drive generally has a side thrust due to the direction of rotation of either the propeller or other propulsion device. This side thrust may be countered by employing twin counterrotating outboard drives. For this and a variety of other reasons, it has been increasing practice to use such twin outboard drives, be they outboard motors or the outboard drive unit of an inboard-outboard arrangement.
In connection with such twin outboard drives, normally there is a separate internal combustion engine that powers each outboard driven. In order to achieve the counterrotation of the outboard drives, either the internal combustion engines must rotate in opposite directions or the gearing associated in the drive between the engine and the propulsion device must include a reversing mechanism for reversing the direction of rotation. In addition, each outboard drive normally includes its own forward, neutral, reverse transmission so as to permit propulsion of the watercraft in either forward or reverse directions.
Because of the fact that the outboard drives, either outboard motors or inboard-outboard drives, may be used either singly or in pairs, it is very desirable if the same basic construction can be utilized for both single and twin installations. This presents problems in connection with twin installations since, as aforenoted, the drives should rotate in opposite directions in such applications.
It is, therefore, a principal object of this invention to provide an improved and simplified arrangement for permitting reverse rotation of a marine outboard drive.
It is further object of this invention to provide a marine outboard drive that lends itself to ease in reversing the direction of rotation without necessitating major changes to the overall construction.
In conjunction with most conventional outboard drives, they are designed so that the input shaft rotates in a constant direction and the driving thrust on the unit always apply in the same direction. However, when the drive is designed so as to be driven in reverse directions for facilitating application with twin drives, the previously proposed constructions have not been completely satisfactory.
It is, therefore, a still further object of this invention to provide a marine outboard drive which can easily be rotated in either of two selected directions and wherein the mechanism is designed so as to take loadings regardless of the direction of drive.