CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to and the benefit of U.S. Provisional Application No. 63/369,991, filed August 1, 2022, and titled “LOWER UNIT STEERING CONTROL SYSTEM”, the entirety of which is incorporated herein.

TECHNICAL FIELD

[0002] The present invention generally relates to a steering system for a thruster (e.g., a trolling motor) and, more particularly, to a submersible steering system that can reduce the force reacted about a pivot mount when the motor is subjected to high loads.

BACKGROUND

[0003] A thruster is a generic term for a device that applies a thrust vector affecting the position and/or bearing of a vehicle (e g., a boat), which typically includes a motor that drives a propeller. A thruster may include the boat’s primary motor (i.e., a motor connected to the internal controls and steering mechanism of the boat) or one or more trolling motors (i.e., a self-contained electric motor that can be mounted/de-mounted from the boat and is generally smaller and less powerful than the primary motor). As shown in FIG. 1, external forces (e.g., wind, waves, etc.) can push a boat a particular distance (Range R) from a target position (T) and/or rotate the boat’s Heading H a particular angular offset from the target position (T). Application of appropriate thrust vectors generated by thruster(s) can return the boat to the target position.

[0004] A typical trolling motor includes a steering control system located somewhere substantially above the main thruster, typically above the water line. Such systems often include a shaft to connect the steering controls (e.g., steering control system) to the main thruster. Tn some cases, the steering control system includes a dedicated motor that acts to rotate the shaft. As trolling motor makers have pushed the boundaries of the amount of thrust and shaft length to accommodate larger vessels, it has created a significant moment about the pivot mount of the trolling motor. In some cases, the need to run power and control cables through the shaft to the main thruster has further contributed to weakness of the shaft. Although stronger pivot mounts with better bearing systems have been created to accommodate these forces, it is reaching the point where it is excessively costly and burdensome. An improved trolling motor with a lower unit steering control system that can accommodate the increased force and reduce the moment about the pivot mount is needed.

SUMMARY

[0005] Embodiments of the invention described herein relate to an improved trolling motor. This application will often describe the steering control system used to rotate the steering shaft thruster of a marine trolling motor. However, the ideas described herein can apply to any steering of any type of motor (e.g., automobile, droid, machinery, etc.) and to any steering control action (e.g., crankshaft, linkage assembly, etc.). As thrust forces and shaft lengths of trolling motors have increased to accommodate larger vessels, Applicant appreciated that a significant moment could result about the pivot mount, which can lead to failure of the bearings of the pivot mount and the resulting steering capabilities provided by the steering control system, among other negative outcomes. While one solution may be to use stronger pivot mounts with improved bearings to counter the increased moment about the pivot mount, this approach can increase costs dramatically. [0006] Applicant has invented a more cost-effective (among other benefits) solution to the problem. In particular, embodiments of the present invention feature a trolling motor with a submersible steering control system that locates the steering control unit closer to the lower unit (e.g., main thruster) of the trolling motor. In some cases, the steering control system can be integrated with the lower unit. This approach significantly reduces the moment generated about the pivot mount and also between the steering control system and the lower unit. Location of the steering control unit closer to the lower unit also eliminates the need to run power and connection cables through a large portion of the steering shaft, which enables a larger portion of the shaft to be solid rather than hollow. The stronger more robust steering shaft counteracts the force applied from the thruster better than a more hollow shaft, which further reduces the moment generated about the pivot mount. This approach was not previously attempted by others skilled in the art because of the challenges associated with submerging an dynamic electromechanical control system; however, Applicant discovered that the benefits of this approach can outweigh the challenges

[0007] In general, in one aspect, embodiments of the invention feature a trolling motor. The trolling motor can include a mount adapted to removably couple to a marine vessel, a shaft having a proximal end coupled to the mount and a submersible distal end, a submersible steering control system coupled to the shaft distal end, and a submersible thruster rotatably coupled to the steering control system.

[0008] In various embodiments, the mount can be adapted to be removably coupled to a deck of the marine vessel. The marine vessel can include a recreational fishing boat. The shaft can include a length in a range from three to ten feet and can be a solid cross section. The shaft can include a plurality of vertebrae stacked to form a column. The shaft can include at least one inelastic tension element threaded longitudinally through the plurality of vertebrae to link the vertebrae, wherein at least a portion of the shaft has a flexible configuration when the at least one tension element is released and a stiffened linear configuration when the tension element is tensed to react torque and bending moments on the shaft. The submersible steering control system can include a brushed DC motor. The submersible steering control system can be rotatably coupled to the submersible thruster with a steering shaft. The submersible thruster can include a horsepower in a range from about 0.25 hp to about 10 hp, about 0.3 hp to about 7.5 hp, about 0.33 hp to about 5 hp, or about 0.5 hp to about 3.5 hp.

[0009] In general, in another aspect, embodiments of the invention feature a method of manufacturing a trolling motor. The method can include the steps of coupling a mount to a proximal end of a shaft, such that the mount is adapted to removably couple to a marine vessel; coupling a submersible thruster to a distal end of the shaft; and coupling a submersible steering control system adapted to control the submersible thruster to the shaft.

[0010] In various embodiments, the submersible steering control system can be coupled proximate to the submersible thruster. The marine vessel can include a recreational fishing boat. The shaft can include a length in a range from three feet to ten feet and can be a solid cross section. The shaft can include a plurality of vertebrae stacked to form a column. The shaft can include at least one inelastic tension element threaded longitudinally through the plurality of vertebrae to link the vertebrae, wherein at least a portion of the shaft has a flexible configuration when the at least one tension element is released and a stiffened linear configuration when the tension element is tensed to react torque and bending moments on the shaft. The submersible steering control system can include a brushed DC motor. Tn some instances, the method can also include the step of coupling the submersible steering control system to the submersible thruster with a steering shaft, such that the submersible steering control system is rotatably coupled to the submersible thruster. The submersible thruster can include a horsepower in a range from about 0.25 hp to about 10 hp, about 0.3 hp to about 7.5 hp, about 0.33 hp to about 5 hp, or about 0.5 hp to about 3.5 hp.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] In the drawings, like reference characters generally refer to the same parts throughout the different views. Also, the drawings are not necessarily to scale, emphasis instead generally being placed upon illustrating the principles of the invention. In the following description, various embodiments of the present invention are described with reference to the following drawings, in which:

[0012] FIG. 1 is an example diagram depicting various forces that act on a boat, according to various embodiments;

[0013] FIG. 2 is a side schematic view of a trolling motor with a conventional steering control system, according to various embodiments;

[0014] FIG. 3 is a side schematic view of a trolling motor with a lower unit steering control system, according to various embodiments; and

[0015] FIG. 4 is a parameter chart listing exemplary low, nominal, and high values of various parameters related to the submersible steering system, according to various embodiments.

DETAILED DESCRIPTION [0016] Tn various embodiments, the present invention is directed to an improved trolling motor with a lower unit (e.g., submersible) steering control system.. A trolling motor can provide for positioning and anchoring of a marine vessel. Examples of boat positioning and anchoring systems can be found in U.S. Patent No. 5,491,636, issued on February 13, 1996 and titled “Anchorless boat positioning employing global positioning system,” and U.S. Patent No. 6,678,589, issued on January 13, 2004 and titled “Boat positioning and anchoring system,” both of which are incorporated herein by reference in their entireties. FIG. 2 shows a trolling motor with a steering control system 1 located somewhere substantially above a main thruster 2, typically above the water surface 7. Trolling motor systems can include a shaft 4 that is rotatably coupled to a pivot mount 5 to removably couple the trolling motor system to a marine vessel (e.g., a recreational fishing boat). The shaft 4 can have a length in a range from three feet (36 inches) to ten feet (120 inches), e.g., in a range from 42 inches to 114 inches, in a range from 48 inches to 108 inches, in a range from 54 inches to 102 inches, in a range from 60 inches to 96 inches, in a range from 66 inches to 90 inches, in a range from 72 inches to 84 inches, or in some cases above or below these ranges. Example standard issue lengths of the shaft 4 are 84 inches and 96 inches. A steering handle (not shown) can be coupled to the top of the shaft 4. The lower unit 3 can be coupled to the bottom (e.g., a submersed end) of the shaft 4. The steering handle 6 (or another manual or powered mechanism of the steering control system 1) can rotate the shaft 4 about the pivot mount 5 to change the direction of the thrust vector(s) output by the main thruster 2 of the lower unit 3. Examples of techniques for determining the thrust vector(s) can be found in U.S. Patent No. 5,491,636, issued on February 13, 1996 and titled “Anchorless boat positioning employing global positioning system”, and U.S. Patent No. 6,678,589, issued on January 13, 2004 and titled “Boat positioning and anchoring system”, both of which are incorporated by reference herein in their entireties.

[0017] In general, in various embodiments, the invention includes a trolling motor with a lower unit steering control system 1 located closer to the lower unit 3 than in conventional trolling motor system. In some embodiments, the lower unit steering control system 1 is either fully or partially submerged and located fully or partially below the water surface 7. In general, the steering control system 1 can be located at any appropriate distance from the lower unit 3, e.g., within 0.5 inches, within 1 inch, within 2 inches, within 4 inches, within 10 inches, within 20 inches, within 40 inches, within 60 inches, within 80 inches, or within 100 inches. In some embodiments, the lower unit steering control system 1 can be integrated with the lower unit 3. As an example, if the lower unit 3 resembles the body of a submarine, the lower unit steering control system 1 can be housed in an area resembling the conning tower of the submarine.

[0018] Accordingly, in some embodiments, the point of rotation is located at or about the lower unit 3 (e.g., via the lower unit steering control system 1). In some embodiments, placing the point of rotation at or about the lower unit allows forces associated with rotating the thruster (e.g., thruster 2) to be reduced as compared to if the steering control system 1 or other point of rotation was located higher (e.g., at or about the mount 5, also see FIG. 2 for exemplary existing design), thereby improving the overall structural design of the motor (compared to existing designs).

[0019] FIG. 3 is a side schematic view of a trolling motor with a submerged lower unit steering control system 1. As shown, the trolling motor system can include a mount 5 adapted to removably couple to a marine vessel. The trolling motor system can include a shaft 4 coupled (e g , fixedly coupled, removably coupled, rotatably coupled) to the mount 5 and a bottom end submersed below the water surface 7. In some embodiments, the shaft comprises a hollow portion therein. In some embodiments, the hollow portion acts as a passageway coupling one or more components to the trolling motor 3 and/or steering control system 1. For example, one or more wires, cables, etc. can be directed through the shaft hollow portion.

[0020] In some embodiments, the portion of the shaft 4 between the mount 5 and the steering control system 1 can be substantially solid or have a reduced hollow portion therein, because there is a reduced amount of power and control / connection wires needed to traverse the shaft over that portion. In some cases, there are no power and control / connection wires traversing the shaft over that portion. In some embodiments, locating the steering control system 1 closer to the lower unit 3 than conventional systems results in a much longer solid portion of the shaft than conventional systems (where most if not all of the shaft is hollow). Accordingly, the shaft 4 in Applicant’s invention can be much stronger and counteract significantly more force than a hollow shaft, thereby reducing the amount of force counteracted by the mount 5, which eliminates or reduces failure of the mount 5. In some embodiments, the trolling motor system having the shaft 4 fixedly coupled to the mount 5 can have increased stability / strength at the coupling mechanism, which can further eliminate or reduce failure at the mount 5.

[0021] In various embodiments, as shown in FIG. 3, the lower unit steering control system 1 can be coupled (e.g., fixedly coupled, removably coupled, rotatably coupled) to the bottom end of the shaft 4. The lower unit steering control system 1 can be any type of steering control mechanism. For example, the lower unit steering control system 1 can be a gear or belt drive driven by a DC motor, direct drive stepper motor, or any other appropriate actuator. In some embodiments, the lower unit steering control system 1 can include means of positional feedback (e g , encoder, potentiometer, etc.) that provides angular position feedback to an operator or an external control system. The angular positional feedback can be used to determine the direction of the thrust vector(s) output by the main thruster 2 of the lower unit 3 as described herein. In some embodiments, the steering control system is located from about 0 to 10 ft, about 1 to 8 ft, about 2 to 6 ft, or about 3 to 5ft below the water line surface 7. In some embodiments, the steering control system is located from about 0 to 12 inches, about 1 to 10 inches, about 2 to 8 inches, or about 3 to 5 inches above the water line surface 7.

[0022] In some embodiments, placing the point of rotation at or about the lower unit (as described herein) allows the thruster 2 to be a standalone azimuthing thruster. Accordingly, this provides for greater flexibility in mounting methods. For example, in some embodiments, one or more of the mount 5, the shaft 4, the steering control system 1, and the trolling motor 3 represents a modular component of the invention. As disclosed herein, in some embodiments, the shaft is removably coupled to the mount and/or one or both of the steering control system and the trolling motor. Accordingly, in some cases, various types of shafts can be swapped based on action by the marine vessel (e.g., remaining at a stationary position in the open water, docking at a marina, etc.). Other mounting methods (e.g., flex shaft, stern thruster, etc.) may also or alternatively employed for any embodiment described herein. Thus, in some cases, providing a standalone azimuthing thruster allows for it to be used with multiple mounting methods.

[0023] In various embodiments, and in general, the lower unit 3 can include any form of thruster, for example, a propeller as shown in FIG. 3. In general, the thruster 2 can include any appropriate horsepower, e.g., in a range of about 0.25 hp to about 10 hp, about 0.3 hp to about 7.5 hp, about 0.33 hp to about 5 hp, or about 0.5 hp to about 3.5 hp. Tn some embodiments, the steering control system 1 is fixedly coupled with the lower unit 3 and corresponding thruster 2. In some embodiments, the steering control system 1 and the lower unit 3 (and corresponding thruster 2) are rotatable about the shaft 4 (e.g., about a longitudinal axis of the shaft 4), such that the steering control system 1 and the thruster 2 rotate in unison. In some embodiments, the steering control system 1 is mounted onto and/or integrated with lower unit 3. In some embodiments, the steering control system 1 is coupled to the lower unit 3 via a steering shaft 8 that may rotate in unison with the steering control system 1 and lower unit 3. In some embodiments, the steering shaft 8 has a length (e.g., between the steering control system and lower unit) of about 0.1 inches to about 24 inches, of about 0.5 inches to about 16 inches, of about 1 inch to about 12 inches, of about 3 inches to about 9 inches, or about 4 to 5 inches. [0024] In various embodiments, the steering control system 1 and lower unit 3 can be deployed and retracted from an underwater environment using any known technique. For example, as described above the steering control system 1 and lower unit 3 can be coupled to a shaft 4. The shaft can be rigid (as depicted) and deployed/retracted by linear motion or flexible and deployed/retracted by a coiling/uncoiling motion. In other embodiments, the steering control system 1 and lower unit 3 can be coupled to a transom mounted deployment system that can deploy/retract (motorized or manually) in a linear or non-linear manner.

[0025] In some cases, the lower unit steering control system 1 can be rotatably coupled to the lower unit 3 with the shaft 4 or a steering shaft 8 (e.g., a secondary shaft located between the lower unit 3 and the steering control system). The lower unit steering control system 1 can rotate the lower unit 3 (e.g., by shaft 4 or the steering shaft 8) to change the direction of the thrust vector(s) output by the thruster 2 of the lower unit 3. In some embodiments, the steering shaft 8 has a length (e.g., between the steering control system and lower unit) of about 0.1 inches to about 24 inches, of about 0.5 inches to about 16 inches, of about 1 inch to about 12 inches, of about 3 inches to about 9 inches, or about 4 to 5 inches.

[0026] In some embodiments, the shaft 4 can be configured to have a flexible configuration to enable improved storage and a stiffened configuration to be used during operation. In some such cases, the shaft 4 can include a plurality of stacked vertebrae to form a column. The shaft 4 can include a tension element (e.g., an inelastic tension element) threaded longitudinally through the plurality of vertebrae to link the vertebrae. Some or all of the vertebrae of the plurality of stacked vertebrae can be in a flexible configuration when the tension element is released, and some or all of the vertebrae of the plurality of stacked vertebrae can have a linear and/or stiffened configuration when the tension element is tensed. Examples of the shaft 4 having this flexible and stiffened configuration are described further can be found in U.S. Patent Application Publication No. 2020/0290714 Al, published on September 17, 2020 and titled “Stiffening shafts for marine environments”, which is incorporated by reference herein in its’ entirety.

[0027] FIG. 4 is a chart including example parameters related to the submersible steering system. Each numerical value presented herein is contemplated to represent a minimum value or a maximum value in a range for a corresponding parameter. Accordingly, when added to the claims, the numerical value provides express support for claiming the range, which may lie above or below the numerical value, in accordance with the teachings herein. Every value between the minimum value and the maximum value within each numerical range presented herein (including the low, nominal, and high values shown in the chart shown in FIG. 4), is contemplated and expressly supported herein, subject to the number of significant digits expressed in each particular range.

[0028] Having described herein illustrative embodiments of the present invention, persons of ordinary skill in the art will appreciate various other features and advantages of the invention apart from those specifically described above. It should therefore be understood that the foregoing is only illustrative of the principles of the invention, and that various modifications and additions, as well as all combinations and permutations of the various elements and components recited herein, can be made by those skilled in the art without departing from the spirit and scope of the invention. Accordingly, the appended claims shall not be limited by the particular features that have been shown and described but shall be construed also to cover any obvious modifications and equivalents thereof.