Removable marine gearcase plate

Details Removable marine gearcase plate Removable marine gearcase plate

2000-07-21

2002-12-24

Avila, Stephen (Department: 3617)

Marine propulsion

Screw propeller

With means effecting or facilitating movement of propulsion...

Reexamination Certificate

active

06497594

ABSTRACT:

BACKGROUND OF THE INVENTION
This invention relates generally to propulsion systems and, more particularly, to an engine mounting assembly for a marine propulsion system.
Mechanical propulsion systems for propelling watercraft generally are classified as either outboard systems or inboard systems. Outboard systems typically are characterized by an outboard motor mounted to a vertical transom plate located on an outside stern of a boat hull. A propeller drive unit is attached to the motor, or powerhead, and extends from the powerhead into the water to generate thrust and propel the watercraft. Outboard motor systems are versatile, compact, and cost-effective units that are relatively easy to install on the boat hull. Also, because the outboard system is attached to the outside of the hull, the outboard motor system generally does not occupy interior space of the boat hull. However, due to structural constraints of the vertical transom plate mounts of outboard systems, watercraft with outboard systems are typically limited to certain motor capacities within size and weight constraints.
Inboard systems are typically characterized by larger, complicated, and relatively expensive engines in comparison to outboard systems. Inboard system engines are mounted in an engine compartment in a boat hull interior, and a drive unit, or stern drive, extends through a vertical wall of the boat hull into the water to generate thrust and propel the watercraft. Inboard systems, however, are much more complicated to install in a boat hull, which further increases the cost of a watercraft. Furthermore, bulky inboard engines and engine compartments often occupy a substantial amount of interior hull space due to the proximity of the engine compartment to a running surface of the hull.
BRIEF SUMMARY OF THE INVENTION
In an exemplary embodiment of the invention, a removable gearcase plate for a marine propulsion system allows drop down installation of the marine propulsion system through a recess in a platform extending from a boat hull. The gearcase plate includes contoured edges conforming to a shape of a top surface of a gearcase, and covers only a portion of the gearcase top surface. The removable plate is attached to the gearcase adjacent a trunnion that is also attached to the gearcase top surface. After the gearcase is attached to a pre-installed trunnion of the marine propulsion system, the gearcase plate is attached to the gearcase to complete installation.
In an exemplary embodiment, the removable gearcase plate is part of a marine propulsion system including an outboard propulsion system powerhead mounted to a horizontal mounting plate in an outside engine compartment enclosed by an engine cover at a stern of a watercraft. The marine propulsion system includes an upper unit that includes the powerhead and a lower unit that includes a propeller drive unit. A four point mounting assembly eases installation of the upper and lower units and absorbs vibration of the upper and lower units to produce smooth, quiet propulsion of a watercraft. The outboard powerhead is mounted stationary to the horizontal mounting plate, and a steering arm yoke and trunnion assembly is attached to the transom plate and extends outside of the boat hull to maneuver the watercraft.
The outboard powerhead, the horizontal mounting plate, and the steering arm yoke and trunnion assembly are pre-assembled, and the assembly is lowered at least partially through a recess in the platform extending from the boat hull. The transom plate is secured horizontally to the platform above a running surface of the hull. A pre-assembled gear shift mechanism, gearcase, and propeller are then attached to the trunnion, and the removable gearcase plate is attached to the gearcase. Installation is completed by making hydraulic connections for trim, tilt, and steering of the propeller drive unit, and by making appropriate fuel, electrical and control system connections to the various components of the propulsion system.
Thus, the removable gearcase plate facilitates a marine propulsion system that provides the versatility, compactness and cost savings of an outboard powerhead with the stability and performance advantages of an inboard system. Structural limitations and instability of vertical transom plate mounts are avoided by mounting the outboard powerhead to the horizontal mounting plate in the boat hull interior.
Drop down installation of pre-assembled propulsion system components greatly simplifies installation in comparison to conventional inboard systems which, when combined with cost savings of an outboard powerhead, substantially reduces the cost of a completed watercraft. Further, because the outboard powerhead is located outside the vertical wall of the hull, the powerhead does not occupy any interior space available for use and enjoyment by operators, for placement of furniture, or for storage space.


REFERENCES:
patent: 2633817 (1953-04-01), Pedranti
patent: 2681029 (1954-06-01), Canazzi
patent: 3382839 (1968-05-01), Kiekhaefer
patent: 3452704 (1969-07-01), Watkins
patent: 3982496 (1976-09-01), Blanchard
patent: 4040378 (1977-08-01), Blanchard
patent: 4911666 (1990-03-01), Gage et al.
patent: 4959033 (1990-09-01), Bland et al.
patent: 5342228 (1994-08-01), Magee et al.

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