This invention provides a vertical-input outboard-motor angled-drive lower unit apparatus and method for improved operations.
Conventional outboard motors have performance deficiencies when operating in shallow, muddy, marshy water or water choked with vegetation or obstacles. The propellers are mounted perpendicular to the water surface and therefore must be submerged at least the full length of their diameters. The gearboxes are located immediately in front of the propellers and therefore must be submerged, placing a bulk of material under water where it generates drag. Cooling is achieved by taking water in through a port and circulating it, which can lead to corrosion and damage when used in salty or polluted water, and to blockage of the intake port and overheating when used in muddy or vegetation- or obstruction-filled water. When being operated in reverse, a significant portion of reverse thrust is directed toward the water surface where it meets the negligible resistance of air pressure and is wasted while churning up the water surface, or is directed toward the transom of the boat where that portion of the thrust is counteracted. The conventional outboard motors are subject to fouling and damage from obstructions, including thick vegetation and floating objects.
Typical shallow-water outboard motors are known, having an output shaft and propeller extending downward into the water at an angle. These shallow-water outboard motors have cumbersome gearboxes located entirely above the water line, where they are subject to overheating. The gearboxes are attached to the outboard-motor engine at the back of the engine and can only be driven by engines having a horizontal rotational output, excluding engines having a vertical rotational output. The gearing and connections of these shallow-water outboard motors make shifting between forward and reverse awkward and cumbersome and place the propeller at a long distance from the steering pivot point, making steering operations awkward and cumbersome. These typical shallow-water outboard motors, when operated in reverse, exhibit the same defects as the conventional outboard motor, with a significant portion of reverse thrust being wasted against the air and the transom, with churning at the surface, and are subject to fouling and damage from obstructions.
What is needed is an outboard-motor lower unit which utilizes engine power provided as vertically oriented rotation, which provides output at an angle to the water surface, which provides water cooling without blockage or internal corrosion, which provides easy and efficient shifting from forward to reverse, which provides a smaller distance from the steering pivot point to the propeller, which shields against damage or fouling by objects in the water, and which redirects otherwise wasted thrust, especially in reverse, into useful thrust without churning the water surface.
This invention provides a vertical-input outboard-motor angled-drive lower unit apparatus and method for improved operations especially in shallow, muddy, marshy water or water choked with vegetation or obstacles. Vertically applied single-direction rotational power from an outboard motor engine is transferred to operator-controlled forward and reverse rotational power applied at an acute angle to the horizontal water surface. The apparatus is cooled by an external flow of water without being taken into any port which might become blocked. A thrust redirection plate reflects otherwise wasted propeller thrust, especially when operating in reverse, for more efficient operation and reduced churning of the water surface. An angled skeg and the angled orientation of the output shaft and housing deflect obstructions.
Reference will now be made to the drawings, wherein like parts are designated by like numerals, and wherein:
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The vertical-input outboard-motor angled-drive lower unit 10 uses rotational force supplied by the outboard-motor engine to a vertical input shaft 31 and transfers either the force or the reversed rotational direction of the force to the propeller mount 39, which is angled away from the vertical orientation of the vertical input shaft 31. A propeller mounted on the propeller mount 39 is at an acute angle to the surface and presumably to the bottom of the water. The preferred angle is 30 degrees from horizontal. At this angle, a propeller will only require a vertical clearance of half its diameter, for example, a 10-inch diameter propeller will only require a 5-inch depth of water. A thrust redirection plate 61 is provided, above the mounted propeller and at a less-acute angle to the surface of the water. When the propeller is thrusting to the rearward and downward, pushing the boat forward, the thrust redirection plate reflects the peripheral part of that force away from breaking the surface of the water and being wasted. When the propeller is thrusting to the forward and upward, pulling the boat rearward, the thrust redirection plate reflects the main part of that force, which is initially directed toward the surface of the water and the transom of the boat, into a downward-angled, more efficient thrust. An angled skeg 62 is provided to shield the vertical-input outboard-motor angled-drive lower unit 10 and the mounted propeller.
The vertical-input outboard-motor angled-drive lower unit 10 provides housings 20 enclosing geared shafts 30 and bearings 40. Most of the parts of the housings 20 sit at least partially below the water line during use, which serves to keep the vertical-input outboard-motor angled-drive lower unit 10 cool during use. This cooling provides an advantage over the prior art, where some components are located above the water line and are essentially not cooled, or are cooled by water being taken into ports, which is a less-desirable solution when operating in salty or otherwise corrosive or polluted water or in muddy, vegetation-choked, or otherwise obstruction-filled water, where a water-intake port might become blocked and result in overheating. An angled main housing 21, forward housing 22, input shaft housing 23 output shaft housing 24 and rear housing 25 are provided.
The vertical-input outboard-motor angled-drive lower unit 10 provides a direction-shifting unit 50 which provides improvements over the prior art. A shift actuator rod 51 provides operator control for shifting between forward and reverse gears. Other components of the direction-shifting unit 50 are housed within the rear housing 25 and are consequently at least partially below the water line and are cooled.
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An intermediate shaft 33 with intermediate shaft bearings 43 is provided, enclosed primarily within the angled main housing 21, located below and at a right angle to the vertical input shaft 31, therefore running horizontally, and running from a forward end to a rearward end in relation to the direction of travel of the outboard motor in use. Around the intermediate shaft 33 in a freely rotating manner are mounted a forward gear 34 with forward gear bearing 44 and a reverse gear 35 with reverse gear bearing 45. The forward gear 34 and the reverse gear 35 are each mounted facing inward toward the middle of the intermediate shaft 33 and therefore each facing the other. Both the forward gear 34 and the reverse gear 35 make contact with the input gear 32 and continually rotate with the input gear 32. In use, the forward gear 34 rotates in a direction yielding a propeller rotation producing a forward thrust, and the reverse gear 35 rotates in the opposite direction yielding a propeller rotation producing a reverse thrust.
The intermediate shaft can be rotated either in a forward direction by the forward gear 34 or in a reverse direction by the reverse gear 35. The direction-shifting unit 50 controls which gear is engaged with the intermediate shaft 33, under the control of an operator using the shift actuator rod 51, which moves a shifting wedge 52 enclosed within the rear housing 25. A shifting clutch dog 54 mounted upon the intermediate shaft 33 between the forward gear 34 and the reverse gear 35 engages with either the forward gear 34 or the reverse gear 35 and transfers the rotation of the engaged gear to the intermediate shaft 33. A clutch dog actuator pin 53 is mounted at the rearward end of the intermediate shaft 33. The clutch dog actuator pin 53 makes contact with the shifting wedge 52 and changes position corresponding to the portion of the shifting wedge 52 being contacted. The change of position of the clutch dog actuator pin 53 is transferred to a change of position of the shifting clutch dog 54 such that the shifting clutch dog 54 changes between engaging either the forward gear 34 or the reverse gear 35, thereby shifting the rotational direction of the intermediate shaft 33.
A driving bevel gear 36 with driving bevel gear bearing 46 is mounted at the forward end of the intermediate shaft 33. This driving bevel gear 36 rotates with the intermediate shaft, either in a forward or reverse direction according to the operation of the direction-shifting unit 50.
An output shaft 38 with output shaft bearings 48 is provided below, in line with, and at an acute angle to the intermediate shaft 33. As stated above, the preferred angle is 30 degrees from horizontal, which is 120 degrees from the vertical line of the vertical input shaft 31.
A driven bevel gear 37 with driven bevel gear bearings 47 is mounted at the forward upward end of the output shaft 38. Together, the driving bevel gear 36 and the driven bevel gear 37 transfer the rotational force of the intermediate shaft 33 to the output shaft 38, at an acute angle. The rotational force transferred can be either a forward-thrust producing force or a reverse-thrust producing force.
The rotational force applied to the output shaft 38 is transferred through the propeller mount 39 to a mounted propeller, producing the corresponding forward or reverse thrust.
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Many other changes and modifications can be made in the system and method of the present invention without departing from the spirit thereof. I therefore pray that my rights to the present invention be limited only by the scope of the appended claims.
This application is a continuation-in-part of co-pending application Ser. No. 15/834,797 filed on Dec. 7, 2017, the full disclosure of which is incorporated by reference herein and priority of which is hereby claimed.
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20190178309 | Provost | Jun 2019 | A1 |
Number | Date | Country | |
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20200317316 A1 | Oct 2020 | US |
Number | Date | Country | |
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Parent | 15834797 | Dec 2017 | US |
Child | 16908326 | US |