Abstract: An improved hydraulic system for a twin propeller marine propulsion unit. A vertical drive shaft is operably connected to the engine of the propulsion unit and carries a pinion that drives a pair of coaxial bevel gears. An inner propeller shaft and an outer propeller shaft are mounted concentrically in the lower torpedo section of the gear case and each propeller shaft carries a propeller. To provide forward movement for the watercraft, a sliding clutch is moved in one direction to operably connect the first of the bevel gears with the inner propeller shaft to drive the rear propeller. A hydraulically operated multi-disc clutch is actuated when engine speed reaches a pre-selected elevated value to operably connect the second of the bevel gears to the outer propeller shaft, to thereby drive the second propeller in the opposite direction.

Abstract: An improved hydraulic system for a twin propeller marine propulsion unit. A vertical drive shaft is operably connected to the engine of the propulsion unit and carries a pinion that drives a pair of coaxial bevel gears. An inner propeller shaft and an outer propeller shaft are mounted concentrically in the lower torpedo section of the gear case and each propeller shaft carries a propeller. To provide forward movement for the watercraft, a sliding clutch is moved in one direction to operably connect the first of the bevel gears with the inner propeller shaft to drive the rear propeller. A hydraulically operated multi-disc clutch is actuated when engine speed reaches a pre-selected elevated value to operably connect the second of the bevel gears to the outer propeller shaft, to thereby drive the second propeller in the opposite direction.

Abstract: A skeg assembly for a marine propulsion unit includes a generally U-shaped saddle that is removably attached to the lower torpedo section of the gearcase of the propulsion unit, and a thin wedge-shaped skeg extends downwardly from the saddle. During planing conditions of the boat, the water line is slightly below the lower torpedo section so that the saddle is out of the water. The side surfaces of the skeg having opposed water intake openings each of which is bordered rearwardly by a laterally projecting shoulder that terminates in a sharp vertical edge and the intake openings are bordered forwardly by a curved surface that connects the side surfaces of the skeg. The water intake openings communicate with a water passage in the skeg which, in turn, communicates with a water passage in the torpedo section so that water can be delivered to the cooling system of the propulsion unit.

Abstract: A twin propeller marine propulsion unit for a watercraft. A vertical drive shaft operably connected to the engine is journaled for rotation in a lower gear case and carries a beveled pinion that drives a pair of coaxial bevel gears. An inner propeller shaft and an outer propeller shaft are mounted concentrically in the lower torpedo-shaped section of the gear case and each propeller shaft carries a propeller. To provide forward movement for the watercraft, a sliding clutch, is moved in one direction to operably connect a first of the bevel gears with the inner propeller shaft to thereby drive the rear propeller. When the engine speed reaches a pre-selected elevated value, a hydraulically operated multi-disc clutch is actuated to operably connect the second of the bevel gears to the outer propeller shaft, to thereby drive the second propeller in the opposite direction.

Abstract: A marine drive (10) has two counter-rotating surface operating propellers (12 and 14). The drive has a vertical X-dimension (254) in the range of about 13 inches to 19 inches in combination with a shaft-spacing dimension (258) in the range of about 8 inches to 15 inches in combination with a surfacing dimension .gtoreq. zero. In one embodiment, the shaft-spacing dimension is 13.5 inches, the vertical X-dimension is 16 inches, and the surfacing dimension is 2 inches.

Abstract: In a rotary vane positive displacement pump (28), the pump impeller (56) has weights (68-73) at the outer tips of the vanes (58-63) of greater mass per unit volume than the vanes and increasing outward centrifugal force urging engagement of the outer tips against the pump housing sidewall (44). In another embodiment, enlarged outer tips (86) of the vanes (82) are offset from the radial center-line (83) of the vane in a direction opposite the direction of rotation. In a further embodiment, a plurality of filler blades (91-96) are provided between respective vanes (101-106) and occupy space therebetween and displace volume in the pumping chamber (46). The filler blades have tapered leading edges (93a) accommodating flexure of the respective vane (103) during greatest flexure thereof. In further embodiments, the leading edges of the filler blades have a concave arcuate profile (128, 146) receiving in complementary relation enlarged outer tips (122, 138) of respective vanes upon flexure thereof.

Abstract: An inboard/outboard stern drive system incorporates a chain drive mechanism. A chain drive extends between the propeller shaft and an intermediate shaft mounted in the stern drive lower unit above the waterline during boat operation for driving the propeller shaft in response to rotation of the intermediate shaft. An input shaft is mounted in the upper portion of the stern drive lower unit, and is drivingly engageable with the intermediate shaft. Appropriate gears and/or sprockets are mounted to the input shaft and the intermediate shaft for transferring rotation therebetween. In a preferred embodiment, a reversing mechanism is employed for selectively imparting rotation to the intermediate shaft in either a first or second rotational direction, thereby controlling the direction of rotation of the propeller shaft. The reversing mechanism is disposed above the waterline during normal operation so as not to impinge on the submerged area of the lower unit.

Abstract: A marine drive for a boat (3) includes a longitudianlly extending propeller shaft (17, 37, 38) which effectively carries the propeller hub (18, 41, 42) between a pair of fore and aft conical surfaces (26-29; 44-47; 51-54) which mate with similar conical surfaces associated with the hub. These mating surfaces prevent orbiting movement of the propeller. The mating surfaces also center the hub on its axis and provide for high torque retention. The construction is such that water is kept out of the joint between the hub and propeller shaft, with pre-applied lubricant being retained therein. The inventive concepts may be utilized with a single propeller system (FIG. 2), or dual propeller installation (FIG. 4).

Abstract: A marine propulsion device is provided wherein a flexible bellows (33) surrounding the universal joint (20) disposed between a marine engine (5) and a stern drive unit (2) is mounted to rotate with the universal joint itself. The universal joint is disposed within a chamber (61) delineated by the bellows itself and by end caps (34,43) mounted to the universal joint shafts (25,30). Supports (53,56) for the universal joint bearings (54) are constructed to permit free flow of fluid around the bearings. A quantity of lubricating oil is supplied to the chamber and at least partially fills the chamber when the latter is at rest. Upon driving rotation of the device, the bellows and universal joint and lubricating oil all rotate together. The resultant centrifugal force causes the oil to flow radially outwardly through the bearing supports to lubricate the bearings, with the oil forming a rotating mass engaging the inner bellows face.

Abstract: A marine drive (1) for a boat (3) includes a construction wherein a propeller supporting bearing device (29, 40) is disposed in a recess (28, 39) inside the propeller hub (23, 22). A bearing carrier (24, 37) is concentrically associated with a propeller shaft (20, 18). The carrier is provided with a rearwardly extending nose portion (27, 38) which is telescoped within the forwardly facing recess in an adjacent rearward propeller hub. The propeller shaft is journalled in the bearing device which is disposed between the carrier and the shaft and within the recess. In one aspect of the invention, the carrier is prevented from rotating about the shaft axis (17). In another aspect, a sealing device (26) is disposed between the propeller shaft and the rear end portion (8a) of an adjacent supporting gear case (8). In the embodiment disclosed, dual propellers and dual bearing carriers are utilized, with bearing carrier noses disposed in recesses in both propeller hubs.

Abstract: A marine propulsion device (1) includes a drive housing (6) to which is attached a suitable engine (4), the exhaust of which is pumped downwardly through a suitable passage (20) in the drive housing to adjacent a torpedo housing (7) carrying at least one propeller (9,10). A generally horizontal antiventilation plate (8) is disposed above the torpedo housing, and a strut (22) extends between the plate and the torpedo housing, just forwardly of the upper portion of the propeller. Substantially all of the engine exhaust is forced by the engine from the drive housing passage for discharge into the path of the upper portion of the propeller. In one embodiment, substantially all of the exhaust passes through the strut and is discharged rearwardly therefrom into ventilating engagement with the forward face of the propeller. In another embodiment, a portion of the exhaust (31) is also discharged downwardly through the antiventilation plate onto the upper edge portion of the propeller.

Abstract: A marine drive (1) for a boat (3) includes a longitudinally extending propeller shaft (18, 20) which concentrically carries the hub (21, 22) of a propeller (10, 11) at the aft end of the shaft, with the shaft serving to rotatably drive the hub. The shaft is provided with a threaded outer peripheral portion (48, 36) at its end. The hub is provided with a rearwardly disposed annular flange (44, 32) and an annular rearwardly facing recess (45, 33) having a threaded outer periphery (47, 35). A dual-threaded nut (49, 37) is removably disposed within the hub recess. The outer nut threads engage the hub threads, while the inner nut threads engage the threads of the propeller shaft. A device (56, 43) is provided for securing the nut against threadable rotation in its mounting. The inventive concepts may be utilized with a single or dual propeller system or any other hub and shaft connection.

Abstract: A marine drive unit (1) includes a lower propeller torpedo housing (9) of generally cylindrical configuration having a longitudinal centerline (19). A propeller shaft (17) is mounted in the housing for rotation on an axis (20) offset from the centerline. The shaft is journalled in a forward bearing assembly (18) which is held in place by a support (25) adjustably mounted to the housing and on the offset axis. A nose (30) is removably secured to the forward housing end by a mounting bolt (40) which extends into the support on the offset axis. A single multi-purpose opening or port (34) in the forward end of the nose communicates to an interior entry passage (35) in the nose. The entry passage in turn merges into a pair of passage branches (36,37). One branch (36) is disposed on the offset propeller shaft axis and receives the mounting bolt. The other branch (37) is positioned to communicate with the cooling water passages (21-23) in the lower unit, and which lead to the marine drive engine (4).

Abstract: A marine drive unit (1) includes a lower torpedo housing (9). At least one propeller shaft (21) is mounted in the housing for rotation about a drive axis (17). The propeller shaft is driven by a driving gear (16) suitably connected to a marine engine (4) and mounted on the drive axis. A first forward thrust bearing (41) is disposed between the driving gear and the housing. In addition, a second forward thrust bearing (42) is disposed adjacent the forward end of the propeller shaft. A pre-loading device, in the present embodiment a washer-like Belleville spring (43) of a desired capacity, is disposed to provide an adjustable rearwardly biasing force on the second thrust bearing.

Abstract: A marine drive unit (1) includes a lower gear case (8) forming a torpedo housing (9). A pair of coaxial propeller shafts (21, 25) are rotatably mounted in the housing and carry a pair of propellers (10, 11) thereon. The propeller shafts are driven by a pair of opposed driving gears (16, 24) suitably connected through a generally vertical main drive shaft (14) to a marine engine (4) and mounted on the horizontal drive axis (17). A pair of thrust bearings (44, 45) adapted to carry forward thrust loads are respectively disposed adjacent the facing portions of the opposed driving gears, with the pair being separated by a spacer (46) tightly confined therebetween. The spacer is locked against rotation but is freely floatable in an axial direction, and transfers the forward thrust load from one bearing to the other, so that the load is ultimately transferred from the outer propeller shaft (25) to the inner central shaft (21).

Abstract: A spider differential assembly (7) of a marine drive is constructed so that the spider (16) and its associated spider pinion gears (20) can float in all directions, except about the common central axis (5) of the propeller drive shafts (4, 8). More particularly, a spider is provided with a central hub opening (18) through which the main drive shaft passes. A plurality of radially extending spindles (19) carry the spider gears and extend outwardly where they terminate in an enclosure (30, 31) arranged to prevent circumferential spider movement about the common drive shaft axis, but which permits free spider floating.

Abstract: A marine stern drive for a boat (3) includes a propeller assembly (36) having a carrier (13) for a pair of concentric drive shafts (12, 19) to which are mounted a pair of closely adjacent fore and aft coaxial surface piercing propellers (21, 22) mounted on a common axis. The carrier also includes a downwardly extending skeg (31). The shafts are connected to a source of power (5) and drive the propellers in contra-rotating relationship at essentially equal rotational velocities. The carrier is connected to devices (39-41) for swinging the carrier laterally for steering, and also vertically. A control (45) is provided for positioning and maintaining the carrier vertically such that both contra-rotating propellers are continuously disposed in surface piercing position during normal operation of the drive. The result is that lateral forces created on the propeller carrier by one rotating surface piercing propeller are counterbalanced by the other propeller when the skeg is parallel to the boat centerline (4).

Abstract: In a marine stern drive unit (1), oil is circulated upwardly from the propeller housing (9) and through the drive shaft sleeve (22) to the upper gear case (7). A return oil line (28) connects from the upper gear case and downwardly through the lower gear case (8) to the propeller housing. The return line is disposed within a cooling water chamber (33) communicating with the drive engine (4) to create an intercooling or heat exchanging effect whereby the incoming water from a lake or the like cools the recirculating stern drive unit lubricant. A combination of threaded drive shaft (13, 36) and internally grooved sleeve (37, 38) is utilized to pump the oil through the system.

Abstract: A cone clutch sleeve (18) on a main shaft (15) is moved axially between forward and reverse counter-rotating gears (13 and 14) by a yoke (102) having mirror-image oppositely tapered cams (108 and 109) on opposite sides thereof which are selectively rotatable to engage eccentric rings (132 and 133) on the forward and reverse gears. This engagement drives the yoke away from the one engaged gear and toward the other gear to in turn drive the clutch sleeve out of engagement with the one gear such that torque applied through the cam-engaged gear ring assists clutch disengagement of the one gear such that requisite shift force decreases as speed and torque increases. The eccentric face surface of each ring actuates the yoke and drives the sleeve member out of engagement with the one gear and into engagement with the other gear with a pulsed impact hammer effect due to the eccentricity of the face surface as it rotates in a circumferential plane about the main shaft.

Abstract: Clutch apparatus (2) for a marine drive lower gear case (4) includes a wrapped spring clutch (18) mounted to a propeller shaft (6) for engaging drive gear means (8) for driving the propeller shaft. The clutch is radially expandable to engage the drive gears along an axially extending friction face engagement surface.