Boat Lift
A boat lift for raising boats out of the water to facilitate maintenance and to reduce corrosion and contamination. The boat lift includes two or more boat lift assemblies positioned and spaced apart so that each boat lift assembly lifts approximately the same fraction of the overall weight of the boat. Each boat lift assembly has a lifting structure with bunk cushions mounted on pivoting bunk bases to prevent damage to the boat hull when lifting. Hydraulic lift mechanisms are enclosed within each boat lift assembly providing a cleaner appearance as well as protection against corrosion and fouling. A dual-pulley mechanism enables lifting distances substantially larger than the length of the lift mechanism. A hydraulic control system ensures that all the boat lift assemblies move up and down simultaneously and at the same rate, thereby maintaining the boat horizontal at all lifting positions.
The present application claims priority from U.S. Prov. Pat. No. 62/857,711, filed Jun. 5, 2019.
TECHNICAL FIELD OF THE INVENTIONThe present invention relates to systems for lifting boats out of the water to facilitate maintenance and to reduce corrosion and contamination.
BACKGROUND OF THE INVENTIONBoat maintenance, cleaning, repairs and/or storage may be facilitated by raising the boat out of the water, typically using a boat lift. Thus, boat lifts are now widely used. However, these boat lifts may be visually unattractive at the pier, as well as presenting dangers to both equipment and personnel when a boat has been raised from the water and is suspended on cables with a danger of unwanted swinging motions.
Often, boat lifts have employed cable lifting mechanisms which are essentially overhead cranes. For stability, there are typically at least two or more of these hoisting mechanisms spaced along the length of the boat to enable more even lifting of the hull and to avoid undue bending stresses as the boat emerges from the water and buoyancy is reduced. However, suspending the boat from hanging cables presents difficulties in an outdoor environment since wind forces on the boat may induce swinging which can be hazardous to both the boat and personnel. During lifting or lowering, while the boat is partially out of the water, wave forces present additional opportunities for unwanted boat motions possibly leading to hull damage and/or personnel injuries. In addition to these operational disadvantages, a group of overhead cranes arrayed along the length of a pier clearly will present an unattractive appearance.
Thus, it would be advantageous to configure a boat lift which may raise a boat uniformly with minimal stresses to the hull during lifting, while avoiding environmental effects such as wind and wave forces during lifting and lowering, as well as when the boat has been fully lifted out of the water for maintenance, cleaning, repairs and/or storage.
It would also be advantageous to configure a boat lift with an improved visual appearance at the pier while maintaining these desirable operational improvements.
SUMMARY OF THE INVENTIONAn object of the invention is to provide a lifting system for a boat. The lifting system is designed with improved stability for the boat when it is lifted out of the water, as well as a more attractive visual profile for the lifting assembly.
The foregoing has outlined rather broadly the features and technical advantages of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter. It should be appreciated by those skilled in the art that the conception and specific embodiments disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the scope of the invention as set forth in the appended claims.
For a more thorough understanding of the present invention, and advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:
Various embodiments of the invention provide different advantages over the prior art. Not all embodiments provide all the advantages made possible by the invention.
Some embodiments provide multiple lifting structures for raising and lowering a boat. Embodiments can be adapted to particular application by using any desired number of lifting structures and positioning the lifting structure at different positions to provide the desired support for a particular size and boat design. For example, a light boat may use only two lifting structure, while a heavy boat may use 3, 4, or more lifting structures, and the lifting structure may be closer together under the heavier portions of the boat. The lifting structures are preferably arranged with a center lifting structure at the center of gravity of the boat, with additional lifting structures proportionally placed toward the transom and the bow to keep the boat balanced as it is raised and lowered. Each lifting structure, in one embodiment, can lift about 3,500 pounds. A jet ski lift can use a single lifting structure. In some embodiments, the lifting structures are standardized, and additional lifting structures are added for heavier boats. In other embodiments, each of the lifting structures themselves can be designed for an appropriate load, for example, by using thicker structural components, heavier cabling, and higher capacity hydraulics for heavy boats, or thinner structural components, lighter cabling, and lower capacity hydraulics for lighter boats. That is, a boat lift can be readily customized by changing the capacity and/or the number of lifting structures.
Each lifting structures is preferably supported by, and move up and down on, a lifting beam. The lifting beam is preferably stationary. The top of each lifting beams can be attached, directly or indirectly, at a pier. The bottom of each lifting beam can be supported on the bottom of the water on a submerged footing or can be supported on the side of the pier, depending on the pier structure. If supported on a submerged footing, the lifting beam is typically oriented at an acute angle to the pier. Different lifting beams of the same boat lift may be supported differently. The same lifting beam can be oriented vertically and attached to the side of the pier or slanted and supported by a submerged footing. The design of the lifting beam does not need to be modified for different support methods, thereby standardizing components and providing flexibility in adapting the boat lift to different piers. The boat lift does not rely on vertical posts extending above the water line as part of its lifting and support mechanism, although an optional guide post may extend above the water when a boat is lifted.
The lifting structure is supported on only one side by the lifting beam, that is, the lifting structure is a cantilevered out from the lifting beam. The cantilevered design eliminates the requirement for providing a dock, footing, or other means to anchor the lifting structure on the opposing side of the slip space. This design reduces cost, eases installation, and provides a cleaner-looking boat lift.
By using standardized lifting structures and varying the number of lifting structures and the method of support of the lifting beam (e.g., bottom supported or attached to the side of the pier), the boat lift can be adapted to different sized boats and different pier structures using standardized components. An optional dampener, i.e., shock absorbers, such as springs or pneumatic cylinders, acting as wave attenuators, may be attached to the lifting cables to reduce the forces on the boat lift and on the boat being lifted due to waves and wind.
In some embodiments, cables are used to transfer the mechanical force to lift a boat and the cables are attached to the wave attenuators. Some embodiments use two cables in each lifting assembly, the two cables reduce the required cable thickness and provide redundancy in case one of the cables breaks. In some embodiments, the cables are retracted to lift the boat by a hydraulic cylinder in each of the lift beams. Using a common hydraulic pump to pressurize all of the lift beams facilitates in the boat lift facilitates moving all the lift beams in unison to keep the boat level as it is being lifted. A flow divider is preferably used to ensure equally proportion flow to raise each of the lift assemblies uniformly and keep the boat level as it is being raised. Mechanical flow dividers are preferred as they are more accurate.
Positioning the hydraulic pistons inside the lifting beams keeps the hydraulic mechanism out of sight and reduces the visibility of the boat lift, improving aesthetics. Nothing is exposed and the system provides a lower profile compared to prior art lifts that include winches on top of the I-beams. The lift beam may be sealed to keep the interior with the hydraulic cylinder dry or immersed in oil, or the interior of the lift beam may be exposed to the water. The hydraulic lift assemblies could alternatively be located in or on the lifting beams.
In some embodiments, each lifting beam is connected to a top beam supported by the surface of the pier. The top beams spread the weight of the boat and boat lift over a broad area of the pier, reducing the dependence on connecters screwed into the pier to support the weight of the boat and boat lift. A pier counterweight may be attached to the top beam on the side opposite of the lift beam to counter the weight of the boat as it is lifted out of the water. For example, the pier counterweight may hang below surface of the pier from the top beam on the opposite side of the pier from the The combination of a top beam supported on the surface of the pier and the lifting beam, connected to the top beam and supported on the side of the pier or on the bottom of the water, provides a novel support method that allows much of the boat lift to be invisible when a boat is not being lifted.
As use herein, “pier” refers to any platform adjacent to, or extending in to, a body of water and used as a landing stage for boats.
Lifting structure 116 comprises a plurality (four shown) of bunk cushions 506 which contact the hull of a boat being lifted when the lifting structure is moved vertically upwards (compare
A lower end of lift beam 510 may be attached to pier wall 524 by a bottom foot assembly 513 comprising: a bottom foot beam bracket 520 pivotally-connected by a bottom foot pivot 522 to a stationary bracket 512 (see
Vertical motion of carriage channel 516 along lift beam 510 is supported and guided by an upper roller assembly 534 and a lower roller assembly 532. Each of the roller assemblies 532 and 534 may comprise one or more rollers (see
A beam extension assembly 548 comprising an inner beam extension 546 telescoping into, and rigidly attached to, an outer beam extension 518, provides support for carriage channel 516 (see
It should be noted that, in some embodiments, bottom foot assembly 513 (
During installation of the boat lift, the horizontal spacing between the roller assemblies 532 and 534 should be set to correspond to the width of lift beam 510 so that lower rollers 1105 and upper rollers 1107 will simultaneously be in contact with opposing walls of lift beam 510. Also, the orientation of carriage channel 516 also must be set during installation to be horizontal (independent of the orientation of lift beam 510). Both of these settings are effected by sliding inner beam extension 546 into outer beam extension 518 a distance which simultaneously configures carriage channel 518 to be horizontal while both upper roller assembly 534 and lower roller assembly 532 may roll along the walls of lift beam 510—once this has been achieved, one or more holes are match-drilled through the wall of outer beam extension 518 (over a portion of outer beam extension 518 which overlaps with inner beam extension 546) and then continues through the wall of inner beam extension 546. Once this hole is drilled, a pin, screw or other fastening means may be inserted through the match-drilled hole to lock-in the distance that inner beam extension 546 extends into outer beam extension 518—this operation sets the length of the beam extension assembly 548. During installation of the boat lift, a carriage shaft 1502 is fitted through a hole in carriage channel 516. Slot 1504 may enable adjustment of the location of carriage shaft 1502 along the length of carriage channel 516.
Other types of linear actuators may perform the function of hydraulic cylinder 1702 in some embodiments, such as motorized lead-screw actuators, motorized recirculating-ball lead-screw actuators, motorized rack-and-pinion geared actuators, motorized worm-gear actuators, etc. Different numbers of moving pulleys 1704 and fixed pulleys 1708 may be employed in some embodiments—the choice of number of pulleys may be determined by the requirements for how far to raise a boat from the water, as well as the weight to be raised by each boat lift assembly and the drive capacity of the linear actuator.
In some embodiments, hydraulic lines 3116, 3120, and 3124, may be single bi-directional hydraulic lines in which the pressurized hydraulic fluid may flow out from hydraulic controller 3110 to the lifting assembly to cause upward (lifting) motion, and the pressurized hydraulic fluid may also flow back to hydraulic controller 3110 from the lifting assembly during downward (lowering) motion. In some embodiments, lines 3116, 3120, and 3124 may comprise multiple hydraulic lines, wherein at least one line may enable pressurized hydraulic fluid to flow from hydraulic controller 3110 to the lifting assembly (during lifting), while one or more lines may enable pressurized hydraulic fluid to flow from the lifting assembly back to the hydraulic controller 3110 (during lowering).
Hydraulic controller 3110, operating under control of computer 3102 through commands conveyed over link 3112, may control each of the lifting assemblies 3114, 3118 and 3122 individually to ensure that the boat lift will lift and lower a boat uniformly and smoothly, to avoid undesirable tilting or bending of the boat as it is raised out of the water and an increasing fraction of the weight of the boat falls on the lifting assemblies as buoyant support decreases.
The following are additional example embodiments according to the present disclosure:
A first embodiment, which is a boat lift, comprising multiple boat lift assemblies, at least one boat lift assembly including a lift beam; a lifting structure configured to move along the lift beam; and a lifting actuator assembly, located inside the lift beam and configured to move the lifting structure.
A second embodiment, which is the boat lift of the first embodiment, wherein the boat lift assembly further comprises a top beam; and a pier counterweight; wherein a first end of the top beam is attached to an upper end of the lift beam, and wherein a second end of the top beam is attached to the pier counterweight.
A third embodiment, which is the boat lift of the first embodiment, wherein in the boat lift assembly, the lifting structure further comprises a bunk pivot; and a bunk cushion attached to the bunk pivot.
A fourth embodiment, which is the boat lift of the third embodiment, wherein in the boat lift assembly, the lifting structure further comprises a carriage channel; and a bunk base; wherein the bunk base is attached to the carriage channel, and wherein the bunk pivot is pivotally attached to the bunk base.
A fifth embodiment, which is the boat lift of the first embodiment, wherein in the boat lift assembly, the lifting structure further comprises a guide post.
A sixth embodiment, which is the boat lift of the first embodiment, wherein in the boat lift assembly, a lower end of the lift beam is configured to be mounted on a wall of a pier.
A seventh embodiment, which is the boat lift of the first embodiment, wherein the boat lift assembly further comprises a submerged footing, and wherein a lower end of the lift beam is configured to be mounted on the submerged footing.
An eighth embodiment, which is the boat lift of the first embodiment, wherein in the boat lift assembly, the lifting actuator assembly further comprises a hydraulic cylinder, having a first end attached at an end of the lift beam; a fixed pulley, attached at the first end of the hydraulic cylinder; a piston rod; a piston, inside the hydraulic cylinder, and attached to a first end of the piston rod; a moving pulley attached to a second end of the piston rod; and a cable routed between the fixed pulley and the moving pulley; wherein an end of the cable protrudes from the lifting actuator assembly, and wherein motion of the moving pulley away from the fixed pulley causes the protruding end of the cable to be retracted into the lifting actuator assembly.
A ninth embodiment, which is the boat lift of the eighth embodiment, wherein in the boat lift assembly, the retraction of the cable into the lifting actuator assembly raises the lifting structure.
A tenth embodiment, which is the boat lift of the eighth embodiment, further comprising a control computer; a hydraulic control system, configured with a hydraulic line to at least one boat lift assembly; a connection between the control computer and the hydraulic control system, the connection being configured to send commands from the control computer to the hydraulic control system; a non-volatile computer-readable storage medium, configured to store instructions to be executed by the control computer; and a connection between the control computer and the non-volatile computer-readable storage medium, the connection being configured to relay computer instructions to the control computer.
An eleventh embodiment, which is a boat lift assembly, comprising a lift beam; a lifting structure configured to move along the lift beam; and a lifting actuator assembly, located inside the lift beam and configured to move the lifting structure.
A twelfth embodiment, which is the boat lift assembly of the eleventh embodiment, further comprising a top beam; and a pier counterweight; wherein a first end of the top beam is attached to an upper end of the lift beam, and wherein a second end of the top beam is attached to the pier counterweight.
A thirteenth embodiment, which is the boat lift assembly of the eleventh embodiment, wherein the lifting structure further comprises a bunk pivot; and a bunk cushion attached to the bunk pivot.
A fourteenth embodiment, which is the boat lift assembly of thirteenth embodiment, the lifting structure further comprising a carriage channel; and a bunk base; wherein the bunk base is attached to the carriage channel, and the bunk pivot is pivotally attached to the bunk base.
A fifteenth embodiment, which is the boat lift assembly of the eleventh embodiment, the lifting structure further comprising a guide post.
A sixteenth embodiment, which is the boat lift assembly of the eleventh embodiment, wherein a lower end of the lift beam is configured to be mounted on a wall of a pier.
A seventeenth embodiment, which is the boat lift assembly of eleventh embodiment, further comprising a submerged footing, wherein a lower end of the lift beam is configured to be mounted on the submerged footing.
An eighteenth embodiment, which is the boat lift assembly of the eleventh embodiment, the lifting actuator assembly further comprising a hydraulic cylinder, having a first end attached at an end of the lift beam; a fixed pulley, attached at the first end of the hydraulic cylinder; a piston, inside the hydraulic cylinder; a piston rod, attached at a first end to the piston; a moving pulley attached to a second end of the piston rod; and a cable routed between the fixed pulley and the moving pulley; wherein an end of the cable protrudes from the lifting actuator assembly, and wherein motion of the moving pulley away from the fixed pulley causes the protruding end of the cable to be retracted into the lifting actuator assembly.
A nineteenth embodiment, which is the boat lift assembly of the eighteenth embodiment, wherein the retraction of the cable into the lifting actuator assembly raises the lifting structure.
A twentieth embodiment, which is a method for raising and lowering a boat out of and into the water, the method comprising configuring a boat lift to include a multiple boat lift assemblies, each boat lift assembly including a lift beam; a lifting structure configured to move along the lift beam; and a lifting actuator assembly, located inside the lift beam and configured to move the lifting structure; a control computer; a hydraulic control system, configured with a hydraulic line to at least one boat lift assembly; a connection between the control computer and the hydraulic control system, the connection being configured to send commands from the control computer to the hydraulic control system; a non-volatile computer-readable storage medium, configured to store instructions to be executed by the control computer; and a connection between the control computer and the non-volatile computer-readable storage medium, the connection being configured to relay computer instructions to the control computer; loading instructions from the non-volatile computer-readable storage medium into the control computer; executing the instructions in the control computer; sending commands to the hydraulic control system from the control computer; directing hydraulic fluid through the hydraulic lines from the hydraulic control system to each boat lift assembly to activate the lifting actuator assemblies based on the commands from the control computer.
Although the present invention and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made to the embodiments described herein without departing from the scope of the invention as defined by the appended claims. Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification.
As one of ordinary skill in the art will readily appreciate from the disclosure of the present invention, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized according to the present invention. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.
Claims
1. A boat lift, comprising multiple boat lift assemblies, at least one boat lift assembly including:
- a lift beam;
- a lifting structure configured to move along the lift beam; and
- a lifting actuator assembly, located inside the lift beam and configured to move the lifting structure.
2. The boat lift of claim 1, wherein the lifting structure extends cantilevered from the lift beam.
3. The boat lift of claim 1, wherein the boat lift assembly further comprises: wherein a first end of the top beam is attached to an upper end of the lift beam, and wherein a second end of the top beam is attached to the pier counterweight.
- a top beam for resting on a pier surface; and
- a pier counterweight;
4. The boat lift of claim 3 further comprising a pier deck grating over the top beam.
5. The boat lift of claim 1, wherein in the boat lift assembly, the lifting structure further comprises: wherein the bunk base is attached to the carriage channel, and wherein the bunk pivot is pivotally attached to the bunk base.
- a carriage channel; and
- a bunk base;
6. The boat lift of claim 5 in which the lifting structure further comprises an outer beam extension extending from the carriage channel to the lift beam.
7. The boat lift of claim 6 further comprising at least one roller connected between the outer beam extension and the lift beam.
8. The boat lift of claim 7 further comprising at least a second roller connected between the carriage channel and the lift beam.
9. The boat lift of claim 1, wherein in the boat lift assembly, the lifting structure further comprises a bunk pivot; and a bunk cushion attached to the bunk pivot.
10. The boat lift of claim 1, wherein in the boat lift assembly, the lifting structure further comprises a guide post.
11. The boat lift of claim 1, wherein in the boat lift assembly, a lower end of the lift beam is configured to be mounted on a wall of a pier.
12. The boat lift of claim 1, wherein the boat lift assembly further comprises a submerged footing, and wherein a lower end of the lift beam is configured to be mounted on the submerged footing.
13. The boat lift of claim 1, further comprising an actual within the lift beam and at least one cable connected to the actuator for raising and lowering the lifting structure.
14. The boat lift of claim 13, in which the at least one cable comprises two cables.
15. The boat lift of claim 13, in which the at least one cable is connected to the lifting structure through a damper to attenuate motion due to waves or wind.
16. The boat lift of claim 1, wherein in the boat lift assembly, the lifting actuator assembly further comprises: wherein an end of the cable protrudes from the lifting actuator assembly, and wherein motion of the moving pulley away from the fixed pulley causes the protruding end of the cable to be retracted into the lifting actuator assembly.
- an actuator rod;
- a linear actuator, having a first end attached at an end of the lift beam, and wherein the linear actuator is configured to move the actuator rod linearly along a long axis of the lift beam;
- a fixed pulley, attached at the first end of the linear actuator;
- a moving pulley attached to an end of the actuator rod; and
- a cable routed between the fixed pulley and the moving pulley;
17. The boat lift of claim 16, wherein the linear actuator comprises a hydraulic cylinder.
18. The boat lift of claim 16, wherein the linear actuator comprises a motorized lead-screw actuator, a motorized rack-and-pinion geared actuator, or a motorized worm-gear actuator.
19. The boat lift of claim 16, wherein in the boat lift assembly, the retraction of the cable into the lifting actuator assembly raises the lifting structure.
20. The boat lift of claim 16, further comprising:
- a control computer;
- a hydraulic control system, configured with a hydraulic line to at least one boat lift assembly;
- a connection between the control computer and the hydraulic control system, the connection being configured to send commands from the control computer to the hydraulic control system;
- a non-volatile computer-readable storage medium, configured to store instructions to be executed by the control computer; and
- a connection between the control computer and the non-volatile computer-readable storage medium, the connection being configured to relay computer instructions to the control computer.
21. The boat lift assembly of claim 1 in which the lift beam is sealed to prevent water from contacting the lifting actuator assembly.
22-36. (canceled)
Type: Application
Filed: Jun 4, 2020
Publication Date: Dec 10, 2020
Inventor: Curtis Wayne Brown (Spicewood, TX)
Application Number: 16/893,396