Continuous track outboard motor for watercraft propulsion

A watercraft propulsion system configured to be coupled to the transom of a boat. A continuous track is supported by a suspension frame and operably coupled to an outboard motor.

BACKGROUND AND SUMMARY OF THE DISCLOSURE

Early watercraft propulsion was often provided by paddle wheel systems including a rotating wheel partially submerged in water to provide forward propulsion. Such paddle wheel systems were largely replaced by underwater propellers, which were found to be more efficient when adequate water depth permitted their use.

Continuous track propulsion systems for amphibious vehicles and snowmobiles are known. These continuous track propulsion systems operate on the same general principal as a paddle wheel when utilized for waterborne propulsion, but offering the advantage of keeping a larger portion of the drive train perpendicular to water and therefore offering better efficiency than conventional paddle wheel designs. It is also known that a modern snowmobile can operate across the surface of water when dynamic lift from its track drive system keeps the nose of the snowmobile lifted and the skis ‘skim’ the surface of the water. However, when a conventional snowmobile slows down or stops on the surface of water, it will sink because of the lack of positive buoyancy and the lessening of the dynamic lift provided by the track drive system.

The present invention is configured to take advantage of a continuous track propulsion system, while incorporating it into an outboard motor, and coupling it with existing boats that can accept a standard transom-mounted motor and provide flotation with the advantages of a standard designed boat.

More particularly, the continuous track outboard motor (CTOM) for watercraft propulsion of the present disclosure is configured to be a modular, transom-mounted boat motor that better enables boat operation in shallow and/or obstructed water, where mud, sand, rocks, vegetation, logs, snags, frozen and semi-frozen surfaces, and other obstacles may be impediments to a standard propeller-driven outboard motor. Even specialty surface-drive “mud motors” typically cannot traverse ice or beach scenarios, where the illustrative continuous track outboard motor of the present disclosure can operate. The watercraft propulsion system of the present disclosure is intended to better enable shallow water operations for military, search and rescue, and recreational (e.g., hunting and fishing) small boat operators, by providing a reliable and simple drive mechanism that offers multiple advantages over alternatives such as air boats, air cushion vehicles (hovercraft), mud motors, or other amphibious vehicle propulsion systems.

According to an illustrative embodiment of the present disclosure, a watercraft propulsion system includes an outboard motor, a suspension frame supported below the motor, a drive wheel supported by the suspension frame and operably coupled to the motor, a first driven wheel supported by the suspension frame in spaced relation to the drive wheel, and a second driven wheel supported by the suspension frame in spaced relation to the drive wheel and the first driven wheel. A continuous track is supported by the drive wheel, the first driven wheel and the second driven wheel, the continuous track including an upper run engaging the first driven wheel, the second driven wheel and the drive wheel, and a lower run engaging the first driven wheel and the second driven wheel, the lower run extending below the upper run and including a downwardly facing water engagement surface. A transom mount is configured to couple the motor to the transom of a boat, the transom mount including a trim control for vertical adjustment of the suspension frame relative to the transom, and a tilt control for pivoting adjustment of the suspension frame relative to the transom.

According to another illustrative embodiment of the present disclosure, a watercraft propulsion system includes an outboard motor, a suspension frame supported by the motor, a drive wheel operably coupled to the motor, a first driven wheel supported by a suspension frame in spaced relation to the drive wheel, and a second driven wheel supported by the suspension frame in spaced relation to the drive wheel and the first driven wheel, a track path defined between the drive wheel, the first driven wheel and the second driven wheel. A continuous track is supported by the drive wheel, the first driven wheel and the second driven wheel, the continuous track including a downwardly facing water engagement surface. The suspension frame includes a base member and an upright member coupled to the base member. A base actuator is coupled to the base member for adjusting the length of the base member, and an upright actuator is coupled to the upright member for adjusting the length of the upright member. The distance between the first driven wheel and the second driven wheel may be adjusted to vary the water engagement surface. A controller is operably coupled to the base actuator and the upright actuator for maintaining a constant length of the track path as the length of the base member and the length of the upright member of the suspension frame are adjusted.

According a further illustrative embodiment of the present disclosure, a method of propelling a watercraft includes the steps of providing a boat including a transom, providing an adjustable suspension frame coupled to the transom of the boat, and rotating a continuous track on the suspension frame, wherein the continuous track includes an upper run engaging a first driven wheel, a second driven wheel, and a drive wheel, and a lower run engaging the first driven wheel and the second driven wheel, the lower run extending below the upper run and including a downwardly facing water engagement surface. The method further includes the steps of detecting the speed of the continuous track, and varying the downwardly facing water engagement surface of the continuous track contacting the water based upon the detected speed.

DETAILED DESCRIPTION OF THE DRAWINGS

With reference initially toFIGS. 1-3, an illustrative watercraft propulsion system10is shown coupled to a boat12. The boat12may be of conventional design as including a buoyant hull14configured to be supported on the surface of water15, and having a port side16and a starboard side18extending between a front end or bow20and a rear end or stern22. A vertical wall or transom24is supported by the stern22and extends between the opposing port and starboard sides16and18. The watercraft propulsion system10of the present disclosure is illustratively coupled to the transom24of the boat12by a transom coupler or mount26.

With reference toFIG. 1, a water or boat speed sensor28is illustratively coupled to the hull14of the boat12and is configured to detect the speed of the boat12travelling through the water15. The boat speed sensor28may be of conventional design as including a paddle wheel that is driven in rotation by water impacting paddles. Other types of boat speed sensors may be substituted therefor, such as global positioning sensors (GPS).

With reference toFIGS. 3 and 4, a steering system30is operably coupled to the watercraft propulsion system10for pivoting the propulsion system10about an upwardly extending steering pivot axis32. More particularly, the steering system30may pivot the watercraft propulsion system10to the left and right about an upwardly extending pivot axis32for steering the boat12.

The illustrative watercraft propulsion system10includes a continuous track outboard motor34operably coupled to a user interface36. As further detailed herein, the motor34may include a throttle40for controlling operating speed of the watercraft propulsion system10. The motor34illustratively comprises a conventional outboard engine38of the type used to drive a propeller (not shown). The engine38illustratively includes rotatable drive or crank shaft42extending parallel to the stern22. A suspension frame44is illustratively supported below the motor34and supports an endless or continuous belt or track46driven in movement by the drive shaft42of the engine38. A controller48may be operably coupled to the user interface36and the motor34(FIG. 4).

The illustrative motor34may comprise a two or four stroke internal combustion engine38mounted to a frame50and received within an engine cowling52. The continuous track outboard motor34is illustratively configured such that no water needs to be supplied to an impeller, such as is typically required by a conventional outboard motor. The continuous track outboard motor34is illustratively includes an air cooling system or a closed loop cooling system, either of which is configured to allow the operation in little or no water-such as is the normal method for employing mud motors (air cooled) or snowmobiles (air cooled and closed loop cooled). A closed loop cooling system would illustratively require a heat transfer design that would use contact with the water as a heat sink, but would not require the drawing up of the lake water via an impeller water pump such as in a conventional outboard motor.

While the motor34is illustratively an internal combustion engine38, it should be appreciated that other drive actuators may be substituted therefor. For example, an electric motor or a hydraulic motor may be used as motor34.

The motor34is illustratively configured to drive in rotation the horizontal engine drive shaft42mounted parallel to the stern22of the boat12, and perpendicular to the direction of intended travel of the boat12along longitudinal axis54(FIG. 2). The drive shaft42illustratively transfers its torque to a drive wheel56via a transmission58. In certain illustrative embodiments, the transmission58may be eliminated such that the drive shaft42of the motor34is directly coupled to the drive wheel56.

Illustratively, the transmission58operably couples a driven pulley or wheel60to the drive pulley or wheel62via a belt and/or chain64. The transmission58may further include a clutch system66(e.g., a single or double clutch system) to optimize the torque curve of the engine38. The illustrative clutch system66includes a primary clutch70associated with the drive pulley60, and a secondary clutch72associated with the driven pulley62.

A driven jackshaft74is illustratively mounted on the suspension frame44and extends parallel to the engine drive shaft42. The drive wheel56is rotatably supported by the suspension frame44and is operably coupled to the motor34through the jackshaft74. A coupler76operably couples the driven pulley62to the jackshaft74. The coupler76may comprise a conventional gear assembly or chain (not shown) received within a case or housing78. More particularly, the jackshaft74is configured to drive in rotation the drive wheel56that, in turn, drives the continuous track46. First and second driven wheels80and82are also rotatably supported by the frame44and support the continuous track46. The first and second driven wheels80and82are supported by the suspension frame44in space relation to each other and to the drive wheel56.

With reference toFIGS. 5A-5C, the continuous track46extends along a track path around the wheels56,80and82of a predetermined length (illustratively approximately 8 feet). While the path of the track46is illustratively of a triangular shape based upon the number and location of the wheels56,80and82, it should be appreciate that the path of the track46may vary based upon different numbers and/or positions of track engaging wheels56,80and82. The track46illustratively includes an upper run84engaging the first driven wheel80, and a lower run86extending below the upper run84. In an illustrative embodiment, the upper run84engages the first driven wheel80, the second driven wheel82and the drive wheel56, and the lower run86engages the first driven wheel80and the second driven wheel82. The continuous track46is illustratively formed of a flexible material, such as an elastomeric belt or metal chain, and includes an outwardly facing surface88and an inwardly facing surface90. The continuous track46may be a conventional rubber snowmobile track, selected from many available styles to provide optimum propulsion in when partially submerged in water.

The outwardly facing surface88of the continuous track46illustratively includes a plurality of longitudinally spaced apart protrusions or paddles92. The outwardly facing surface88of the lower run86defines a downwardly facing water engagement surface94extending between the first and second driven wheels80and82. The paddles92of the continuous track46provide for improved water displacement and propulsion of the propulsion system10.

The inwardly facing surface90of the continuous track46includes a plurality of teeth or cogs96, and the wheels56,80,82each include a plurality of teeth or cogs98,100,102configured to engage with the cogs96of the track46. The continuous track46is configured to move around the frame44that is optimally shaped to contact the surface of the water immediately behind the boat12. The continuous track46rides on wheels56,80,82positioned around the frame44so as to minimize friction and minimize amount of water lifted and carried back to toward the engine38. At least one idler wheel104may be rotatably supported by the frame44to assist in guiding the continuous track46and to maintain tension in the track46. The idler wheel104may be operably coupled to a track speed sensor106in electrical communication with the controller48.

The paddles92of the continuous track46illustratively have a length (i.e., distance from the outwardly facing surface88to a tip or outer end of the paddle92) to provide optimal ‘grip’ of the water without causing undesired disturbance (either venting or cavitating) of the water, and of a spacing, or pitch, so that one paddle92does not overly interfere with the supply of water to the successive paddle92that follows behind it. The lateral width of the track46may vary based upon performance requirements. For example, the track46may be narrowed to lighten the track46and for use with a smaller engine38. Metal studs (not shown) may also be supported by the outwardly facing surface88of the track46to allow for improved operation, for example, over frozen or semi-frozen surfaces.

With reference toFIGS. 2 and 3, a housing encasement108is illustratively coupled to the engine cowling52and receives the upper run84of the continuous track46. The housing encasement108includes a rear shield or deflector110extending above the upper run84of the track46proximate the rear wheel82. The rear deflector110is configured to eliminate excessive water lifting and spray, and protect the engine38and the transmission58from over exposure to water and spray. All materials of the watercraft propulsion system10are selected to ensure endurance in a wet environment (plastic or fiberglass cowling, aluminum frame, alloy or composite or plastic wheels and shafts and engine components).

With reference toFIGS. 2 and 3, the transom mount26may illustratively include a clamp112configured to mechanically couple or secure the continuous track outboard boat motor34to the transom24of the boat12. A connector114defines a universal joint with the clamp112. More particularly, the connector defines the steering pivot axis32and a tilt pivot axis115extending substantially perpendicular to the steering pivot axis32and parallel to the stern22.

With reference toFIGS. 2 and 3, the steering system30and the throttle40may be operably coupled to the user interface36. In one illustrative embodiment, the user interface36is defined by a tiller steering and throttle control system116illustratively coupled to the motor34to control rotation of the track46about the steering pivot axis32, and the speed of the motor34and subsequent movement of the track46as a result of rotation of the drive wheel56. The tiller steering and throttle control system116illustrative includes a handle118supporting a rotatable grip120. In this tiller control arrangement, an operator of the boat12illustratively sits near the stern22of the boat12and provides throttle control via the grip120of the handle118, and steers the boat12by moving the tiller handle118left or right as is the standard method with a conventional outboard motor38. The tiller handle118may also include the trim and tilt controls122and124for optimizing the trim and tilt angle of the motor34and continuous track46with respect to the surface of the water15.

In another illustrative embodiment, the steering system30and the throttle40may be operably coupled to the user interface36, for example, through the controller48(FIG. 4). Illustratively, the user interface36may be defined by a console126including a steering wheel128operably coupled to the motor34to rotate the motor34about the steering pivot axis32. The illustrative user interface36may further include a hand (or foot) controlled throttle lever130(or pedal) operably coupled to the throttle40. The console steering wheel128and hand controlled throttle lever130may be substituted for, or used in addition with, the tiller steering and throttle control system116.

The steering console126, illustratively positioned either on the starboard side18or in the center of the boat12, supports the steering wheel128which may be operably coupled to the steering system30(such as a rack-and-pinion or hydraulic steering system) which, in turn, is connected to the outboard motor34. The throttle lever130may be present at the right hand or as a foot control (commonly called “hotfoot”) of the operator and the trim and tilt controls122and124are provided either on the throttle lever130, steering wheel128, or console126that the operator uses. The boat12could also be arranged with dual motors in a console steering scenario, such as is the manner with conventional outboards to provide more power to larger boats.

The motor34may be fluidly coupled to a fuel supply132(e.g., a gasoline tank) via a fluid supply tube134, and in electrical communication with an electrical supply136(e.g., a battery) via an electrical cable138. Both the fuel supply132and the electrical supply136are illustratively mounted inside the hull14of the boat12near the stern22.

With reference toFIGS. 3 and 4, a trim control actuator140and a tilt control actuator142are operably coupled to the transom mount26, and are in communication with the trim and tilt controls122and124, respectively, via the controller48. Each of the trim control and tilt control actuators140and142may be of conventional design, such as a hydraulic or electric jack. Actuation of the trim control actuator140raises and lowers the frame44and drive track46in a generally vertical direction, illustratively to maintain the water engagement surface94in contact with the surface of the water15. Actuation of the tilt control actuator142pivots the frame44and the drive track46about axis115. The tilt control actuator142pivots the frame44to change the angle of the water engagement surface94in response to changing inclination or attitude of the boat hull14relative to the surface of the water15as the speed of the boat increases (which may be measured by the boat speed sensor28).

Illustratively, the trim and tilt controls122and124are operably coupled to the motor34for raising and lowering the motor34relative to the stern22. As noted above, these features are configured to optimize the contact of the propulsion system10with the water15relative to load and speed.

In either illustrative embodiment, using the tiller steering and throttle control system116or the steering console126, the continuous drive outboard motor34is configured to operate in a nearly identical manner to a standard outboard boat motor. An operator that is familiar with tiller or console operated conventional outboard motor would be able to easily operate the continuous track outboard motor34with no significant additional learning required.

With reference now toFIGS. 5A and 5B, the suspension frame44may be an articulating frame configured to modify the path of the continuous track46. In one illustrative embodiment, the frame44includes a base member144, an upright member146and a connecting member148. The drive wheel56is rotatably coupled to the upper end of the upright member146at the intersection with the connecting member148. The first driven wheel80is rotatably coupled the lower end of the upright member146at the intersection with the forward end of the base member144. The second driven wheel82is rotatably coupled to the rear or aft end of the base member144at the intersection with the connecting member148. A suspension frame base actuator150is coupled to the base member144for adjusting the length of the base member144, and thereby the distance between the first driven wheel80and the second driven wheel82. A suspension frame upright actuator152is coupled to the upright member146for adjusting the length of the upright member146, and thereby the distance between the drive wheel56and the first driven wheel80. A connecting actuator154may be coupled to the connecting member148for adjusting the length of the connecting member148, and thereby the distance between the drive wheel56and the second driven wheel82.

The base actuator150and the upright actuator152are operably coupled to the controller48. The controller48illustratively includes a memory156configured to store configuration data. For example, the configuration data may include information associating desired contact between the water engagement surface94of the drive track46in relation to a speed as detected by the boat speed sensor28and/or the track speed sensor106. In response to the detected speed from the sensor(s)28,106, the controller48may operate the trim control actuator140to adjust trim (i.e., vertical height) of the water engagement surface94, and/or may operate the tilt control actuator142to adjust tilt (i.e., angle of the water engagement surface94). The controller48may also adjust the suspension frame44to control the length, and resulting available contact area, of the water engagement surface94.FIG. 5Aillustrates a low speed configuration of the suspension frame44and drive track46, whileFIG. 5Billustrates a high speed configuration of the suspension frame44and drive track46.

In an illustrative operation, if speed detected from the boat speed sensor28and/or the track speed sensor106increases then the base actuator150extends, thereby increasing the length of the base member144(i.e., distance between the first and second driven wheels80and82). Concurrently, the upright actuator152retracts, thereby decreasing the length of the upright member146(i.e., distance between the drive wheel56and the first driven wheel80). The connecting actuator154may adjust accordingly to maintain a constant path length of the track46(and resulting tension within the track46). As such, the downwardly facing water engagement surface94of the track46increases while maintaining a constant path length of the track46.

Conversely, if speed detected from the boat speed sensor28and/or the track speed sensor106decreases, then the base actuator150retracts, thereby decreasing the length of the base member144(i.e., distance between the first and second driven wheels80and82). Concurrently, the upright actuator152extends, thereby decreasing the length of the upright member146(i.e., distance between the drive wheel56and the first driven wheel80). The connecting actuator154may adjust accordingly to maintain a constant path length of the track46(and resulting tension within the track46). As such, the downwardly facing water engagement surface94of the track46decreases while maintaining a constant path length of the track46.

FIG. 5Cshows the suspension frame44in a further illustrative configuration providing for the tilting of the water engagement surface94. For example, if the speed detected from the boat speed sensor28increases, then the base actuator150extends, thereby extending the length of the base member144(i.e., distance between the first and second driven wheels80and82). Concurrently, the connecting actuator154retracts, thereby decreasing the length of the connecting member148and moving the second driven wheel82upwardly relative to the first driven wheel80, while maintaining a constant path length of the track46(and resulting tension within the track46). As such, the downwardly facing water engagement surface94of the track46is pivoted upwardly in order to facilitate engagement with the surface of the water15as the inclination or attitude of the boat12changes as a result of speed. It should be appreciated that if the speed detected from the boat speed sensor28decreases, then the base actuator150may retract, and the connecting actuator may extend, thereby causing the downwardly facing engagement surface94to pivot downwardly.

Advantages of the continuous track outboard boat motor34may be found in the shallow and obstructed water in which it can operate when compared to a traditional propeller driven outboard motor. No part of the motor, other than the paddles92of the continuous track46will be submerged below the surface of the water15, which equates to less drag and shallower water operation. Also, since no water will be used to cool the engine38, as is typically the case with conventional outboard motor, again shallow water operation will be enabled. Even more unique in a continuous track outboard motor34is that operation on ice or surf and even beach scenarios will be enabled. Such operation would compete with the capability of an airboat. Modern airboats use high power engines and air propellers to force a relatively flat bottomed boat over water, ice, swamp, grass, and even land. However the fuel consumption, noise levels, engine configuration, and special boat design and skills required to operate an airboat are sometimes prohibitive for use with most average boaters.

A boat using a continuous track motor34would be intuitively operated by almost any conventional boater, would require little extra skill sets over conventional boating skills, and could enable nearly all the terrain that an airboat could cover without being so purpose built. The only extra modification that a conventional boat might require for a continuous track outboard motor might be a coating or material on the hull—which would typically be aluminum—to lessen friction and increase durability. Polymers and coatings are well known for this employment. Military, law enforcement and rescue personnel using a continuous track outboard motor34could run their small craft right up onto the beach or riverine and delta terrains, and with dual or sufficiently powered single engines, might even be able to power a boat up onto a beach, turn around, and come back into water in a semi-amphibious operation that would require no disembarking from the craft.

The continuous track outboard motor34is illustratively impervious to fouling barriers that might be used to try to snag other types of conventional propeller driven craft. Search and rescue crews with a boat with a continuous track outboard motor34could use small boats for search and rescue on thin ice or ice that turns to open water. The continuous track outboard motor34would allow a craft to be powered across ice, then into thawed, open water areas, and back onto the ice for rescue operations, and in flooding scenarios, without the skills required to operate a helicopter, hovercraft, or airboat that might have to be used for a similar operation otherwise. A small boat equipped with a continuous track outboard motor34would be a multi-use craft with more durability, less specialized skills, and less initial purchase and operating cost than a hovercraft, helicopter, and airboat.

The continuous track outboard motor34provides a unique configuration of a continuous track46being used in a design arrangement of a transom mounted outboard motor configuration, to enable operation with common boats in shallow water and normally inaccessible terrains such as mud and ice. The focus of the continuous track outboard motor34is making a common boat much more flexible without a special, purpose-built craft that is typically high cost. The continuous track outboard motor34also uses commonly available components—hydraulic trim/tilt, jacks, clamps, engines, drive trains, tracks—commonly found in other related industries to configure a design that has a high percentage of off-the-shelf parts to drive a relatively low cost motor system.

The continuous track outboard motor34equipped small boat would be ideal for fisherman who must traverse shallow water, such as is found in multiple freshwater lakes and especially in the saltwater flats of the Gulf of Mexico. The continuous track outboard motor34, with its rubberized track, would also likely prevent injury to marine mammals such as manatees and dolphins, which are known to commonly be cut and even killed by conventional propeller motors. Operators of shallow, rocky rivers, who typically rely on jet boats, would find a continuous track outboard motor34advantageous because of the disadvantages of jet motors requiring high horsepower and their tendency to ingest rocks and sand that wear on or severely damage their impellers.

The continuous track outboard motor34, appropriately set up with a hydraulic lift for adjusting the height above the transom, could be lowered for more contact with terrains such as beach and ice, and with wheels on the front of a boat, could even enable hard surface operation (boat ramps, gravel roads, paved roads, ice, slush, hard packed snow). This could enable access to typically inaccessible waters or surfaces for all manner of individuals-hunters, fisherman, search and rescue, and military.