Marine drive having two counter-rotating surfacing propellers and dual propeller shaft assembly

A marine drive having two counter-rotating surface operating propellers comprising:

• a housing having a horizontal bore and an intersecting vertical bore therein;
• a vertical driveshaft positioned in said vertical bore;
• a pinion driving gear mounted on the lower end of said vertical driveshaft;
• a first inner propeller shaft and a second hollow outer propeller shaft,
• said second propeller shaft positioned over said first propeller shaft to form a dual propeller shaft assembly,
• said dual propeller shaft assembly positioned in said horizontal bore;
• a first surface operating propeller and a second surface operating propeller,
• each of said first and second propellers mounted to a respective one of said first and second propeller shafts,
• one of said propellers being a right hand rotation surface operating propeller,
• the other of said propellers being a left hand rotation surface operating propeller;
• a first driven gear fixed on said first propeller shaft for engagement with said pinion gear for drivingly rotating said first propeller shaft in a first rotational direction;
• a second driven gear fixed on said second propeller shaft for engagement with said pinion gear for drivingly rotating said second propeller shaft in a second rotational direction;
• and
• spool means having
• a bearing support housing fixed in said horizontal bore for supporting said propeller shaft assembly,
• said bearing support housing formed as a first cylindrical member, and a locking member fixed in said horizontal bore adjacent said bearing support housing,
• said locking member formed as a second cylindrical member surrounding the second propeller shaft.

A marine drive having two counter-rotating surface operating propellers comprising:

• a housing having a horizontal bore and an intersecting vertical bore therein;
• spool means positioned in said horizontal bore,
• a first inner propeller shaft and a second hollow outer propeller shaft,
• said second propeller shaft positioned concentrically over said first propeller shaft, said second propeller shaft being supported by said spool means,
• said first propeller shaft rotating in a first rotational direction,
• said second propeller shaft rotating in a second opposite rotational direction;
• a first surface operating propeller mounted to said first propeller shaft and a second surface operating propeller mounted to said second propeller shaft,
• one of said propellers being a right hand rotating propeller,
• the other of said propellers being a left hand rotating propeller;
• and
• retaining means for holding said spool means fixed for non-rotation within said horizontal bore in both said first rotational direction and said second rotational direction as said propellers strike and pierce the surface of the water,
• wherein said retaining means for holding said spool means fixed comprises:
• a first right hand thread set in said horizontal bore;
• and
• a second left hand thread set in said horizontal bore,
• said thread sets being spaced along the rotational axis of said first and second propeller shafts,
• such that said right hand thread set prevents right hand rotational loosening of said spool means, and
• said left hand thread set prevents left hand rotational loosening of said spool means.

A marine drive comprising:

• a housing having a horizontal bore and an intersecting vertical bore therein;
• a first inner propeller shaft;
• a second hollow outer propeller shaft positioned over propeller shaft to form a dual propeller shaft assembly,
• said dual propeller shaft assembly positioned in said horizontal bore,
• said first propeller shaft counter-rotating with respect to said second propeller shaft;
• a vertical driveshaft positioned in said vertical bore;
• a pinion driving gear mounted on the lower end of said vertical driveshaft;
• a fore driven gear on said first propeller shaft and engaged by said pinion gear to drivingly rotate said first propeller shaft in a first rotational direction;
• an aft driven gear on said second propeller shaft and engaged by said pinion gear to drivingly rotate said second propeller shaft in a second rotational direction, said fore and aft driven gears being separated by an axial gap therebetween;
• a thrust bearing transferring forward thrust from said second propeller shaft to said first propeller shaft at a location aft of said fore driven gear.

A marine drive comprising:

• a housing having a horizontal bore and an intersecting vertical bore therein;
• a first inner propeller shaft;
• a second hollow outer propeller shaft positioned over said first propeller shaft to form a dual propeller shaft assembly,
• said dual propeller shaft assembly positioned in said horizontal bore,
• said first propeller shaft counter-rotating with respect to said second propeller shaft;
• a vertical driveshaft positioned in said vertical bore;
• a pinion driving gear mounted on the lower end of said vertical driveshaft;
• a fore driven gear on said first inner propeller shaft and engaged by said pinion gear to drivingly rotate said first propeller shaft in a first rotational direction;
• an aft driven gear on said second propeller shaft and engaged by said pinion gear to drivingly rotate said second propeller shaft in a second rotational direction;
• a tapered roller bearing supporting said aft driven gear for rotation in said housing, said tapered roller bearing having
• an inner race engaging said aft driven gear, and
• an outer race engaging said housing;
• a threaded locking member engaging said housing in thread mounted relation within said horizontal bore and holding said tapered roller bearing in place and preventing rearward movement of said tapered roller bearing and said aft driven gear.

A marine drive comprising:

• a housing having a horizontal bore and an intersecting vertical bore therein;
• a spool positioned in said horizontal bore;
• a first inner propeller shaft and a second hollow outer propeller shaft, said first propeller shaft being within said second propeller shaft and spaced therefrom by a first annulus, said second propeller shaft being within said spool and spaced therefrom by a second annulus;
• a first aft bearing within said first annulus and supporting said first propeller shaft for rotation within said second propeller shaft;
• a second aft bearing within said second annulus and supporting said second propeller shaft for rotation within said spool;
• a first oil passage comprising a passage in said housing supplying oil to said second annulus to lubricate said second aft bearing;
• a second oil passage comprising a passage in said second propeller shaft supplying oil from said second annulus to said first annulus to lubricate said first aft bearing.