Watercraft lift

Abstract

A watercraft lift including opposing first and second lift assemblies, a cradle, and at least one cable. Each lift assembly includes a screw having a shaft and a helical thread and an electric motor configured to rotate the screw. The cradle is suspended from the first and second lift assemblies. The first and second lift assemblies are synchronized thereby balancing the cradle. The at least one cable connects the cradle to the first and second lift assemblies. The at least one cable is configured to raise and lower the cradle upon the motor rotating the screw.

Description

Docket No. 61469-PCTWATERCRAFT LIFTRELATED APPLICATIONS

[0001] The current international patent application claims priority benefit of earlier filed U.S. Non-Provisional Application Ser. No. 19 / 412,067, entitled “WATERCRAFT LIFT”, and filed December 8, 2025, which claims priority benefit, with regard to all common subject matter, of earlier-filed U.S. Provisional Application Ser. No. 63 / 729,616, entitled “UNIVERSAL HIGH SPEED HYDRAULIC WATERCRAFT LIFT", and filed December 9, 2024. The U.S. Provisional Application and U.S. Non-Provisional Application are hereby incorporated by reference, in their entireties, into the current international patent application.BACKGROUND

[0002] Watercraft lifts often use relatively complex hydraulics and mechanical linkages for raising and lowering watercraft. Such systems can be unreliable, complicated, unsightly, and difficult to integrate into docks and other structures. Furthermore, conventional watercraft lifts can make boarding and handling the watercraft dangerous since requiring the watercraft to be laterally centered on the lift often creates a wide gap between the watercraft and the dock.SUMMARY OF THE INVENTION

[0003] Embodiments of the present invention solve the above-mentioned problems and provide a distinct advance in the art of watercraft lifts. More particularly, the present invention provides a watercraft lift that includes one or more lifting assemblies that utilizes a screw for lifting and lowering. The screw and other components of each lifting assembly may be housed in a compact lift tube.

[0004] An embodiment of the present invention is a watercraft lift including opposing first and second lift assemblies, a cradle, and at least one cable. Each lift assembly includes a screw having a shaft and a helical thread and an electric motor configured to rotate the screw. The cradle is suspended from the first and second lift assemblies. The first and second lift assemblies are synchronized thereby balancing the cradle. The at least one cable connects the cradle to the first and second lift assemblies. The at least one cable is configured to raise and lower the cradle upon the motor rotating the screw.Docket No. 61469-PCT

[0005] In another embodiment, each lift assembly further includes a lift tube having an internal chamber. The screw and the electric motor are housed in the internal chamber of the lift tube.

[0006] In another embodiment, the cradle includes a crossbeam configured to index to a bottom of each lift tube for minimizing or eliminating sway of the cradle.

[0007] In another embodiment, the screw is a ball screw. Each lift assembly further includes a nut and a nut brake. The nut is connected to the at least one cable and configured to longitudinally traverse the screw when the screw is rotated. The nut brake is configured to prevent backdrive of the nut.

[0008] In another embodiment, each lift assembly further includes a battery configured to power the electric motor. The electric motor is a direct current (DC) motor and is configured to regeneratively charge the battery when the cradle is lowered.

[0009] In another embodiment, each lift assembly further includes a lift tube having an internal chamber. The battery is positioned in the internal chamber of the lift tube.

[0010] In another embodiment, each lift assembly further includes a brake. Each lift assembly is configured to lower the cradle in an emergency down mode upon release of the brake.

[0011] In another embodiment, each lift assembly further includes a nut, a stopping collar, and a thrust bearing. The nut is connected to the at least one cable and configured to longitudinally traverse the screw when the screw is rotated. The thrust bearing is positioned on the screw near the stopping collar and configured to engage the nut thereby preventing the nut from sticking to the stopping collar.

[0012] In another embodiment, each lift assembly further includes a nut and a cable clamp. The nut is configured to longitudinally traverse the screw when the screw is rotated. The cable clamp is configured to secure the at least one cable to the nut such that opposing ends of the at least one cable extend to the cradle. The at least one cable is configured to self-adjust in the cable clamp by slipping in the cable clamp when a pre-determined load is reached thereby preventing the at least one cable from being overloaded.

[0013] In another embodiment, each lift assembly further includes a nut and a cable retaining means. The nut is configured to longitudinally traverse the screw when the screw is rotated. The cable retaining means is connected to the nut and configured to secure the at least one cable to the nut such that opposing ends of the at least one cable extend to the cradle. The at leastDocket No. 61469-PCT one cable is configured to self-adjust in the nut when one end of the at least one cable is loaded more than the opposing end of the at least one cable by a predetermined ratio.

[0014] In another embodiment, a first portion of the at least one cable extending from the nut is longer than a second portion of the at least one cable extending from the nut. The first portion is pre-loaded a greater amount than the second portion when the cradle is in a home position to reduce a load on the second portion.

[0015] In another embodiment, the cradle includes a middle crossbeam and a rearward crossbeam configured to support a watercraft and a forward crossbeam configured to support a platform. The at least one cable is connected to the middle crossbeam. The watercraft lift further includes an additional cable connected to the forward crossbeam and the at least one cable.

[0016] In another embodiment, the electric motor of the first lift assembly and the electric motor of the second lift assembly are constant RPM motors thereby synchronizing the first and second lift assemblies for controlling a side-to-side level of the cradle.

[0017] In another embodiment, the first lift assembly and the second lift assembly are configured to automatically relevel the cradle when the cradle is in a home position.

[0018] In another embodiment, the watercraft lift further includes a control system having a control wire communicatively connected to at least one of the electric motors of the first lift assembly and the second lift assembly. The at least one cable includes a first cable connecting the cradle to the first lift assembly and a second cable connecting the cradle to the second lift assembly. At least one of the first lift assembly and the second lift assembly further includes a nut connected to one of the first and second cables. The control wire is secured to the nut for lifting the control wire out of the water when the first lift assembly and the second lift assembly raise the cradle.

[0019] In another embodiment, the cradle includes a forward crossbeam, a rear crossbeam, and a crossbeam connector configured to prevent rotation of the forward crossbeam and the rear crossbeam.

[0020] In another embodiment, the electric motor is a submersible motor including a controller and a gearbox. The watercraft lift further includes a submersible battery configured to power the electric motor.

[0021] In another embodiment, each lift assembly further includes a lift tube, a nut, and a nut carrier. The lift tube has an internal chamber. The nut is connected to the at least one cable and configured to longitudinally traverse the screw when the screw is rotated. The nut carrier includesDocket No. 61469-PCT a number of guides, a groove, and a cable clamp. The guides entrain the nut in the internal chamber. The groove is configured to receive the at least one cable therein. The cable clamp is configured to secure the at least one cable to the nut carrier.

[0022] In another embodiment, the watercraft lift further includes a pin and a pin reinforcer. The cradle includes a tubular member. The at least one cable is connected to the cradle via the pin. The pin reinforcer is configured to distribute bending forces in the pin. The pin reinforcer includes geometry for accepting a rope loop and geometry for accepting a cable eye.

[0023] In another embodiment, the at least one cable is a synthetic cable including a bullet embedded therein and configured to engage one of the first and second lift assemblies thereby limiting movement of the cradle.

[0024] Another embodiment is a bracket assembly configured to secure a horizontal watercraft lift beam to a piling. The bracket assembly includes a clip, a central mounting structure, and a pile mounting bracket. The clip is configured to be attached to the watercraft lift beam. The clip is also configured to be secured to the central mounting structure. The pile mounting bracket is configured to be mounted to the piling. The central mounting structure and hence the clip are configured to pivot relative to the pile mounting bracket.

[0025] Another embodiment is a telescoping bracket for raising a watercraft lift on a number of pilings. The telescoping bracket includes a lower tube and an upper tube. The lower tube is configured to be mounted to one of the pilings. The upper tube is configured to be attached to the watercraft lift. The upper tube is configured to translate vertically relative to the lower tube.

[0026] Another embodiment is a watercraft lift including a frame, opposing first and second lift assemblies, a cradle, and at least one cable. The frame includes a number of vertically- extending legs and a crossbeam connecting at least some of the vertically-extending legs. The first and second lift assemblies are mounted on the frame and each includes a screw having a shaft and a helical thread and an electric motor configured to rotate the screw. The cradle is supported by the first and second lift assemblies, The first and second lift assemblies are synchronized thereby balancing the cradle. The at least one cable suspends the cradle from the first and second lift assemblies and extends between the first and second lift assemblies via the crossbeam of the frame. The at least one cable is configured to raise and lower the cradle upon the motor rotating the screw.

[0027] Another embodiment is a watercraft lift including opposing floating dock fingers, opposing first and second lift assemblies, a cradle, and at least one cable. Each of the first andDocket No. 61469-PCT second lift assemblies is mounted on one of the opposing floating dock fingers and includes a screw having a shaft and a helical thread and an electric motor configured to rotate the screw. The cradle is suspended from the first and second lift assemblies. The first and second lift assemblies are synchronized thereby balancing the cradle. The at least one cable connects the cradle to the first and second lift assemblies. The at least one cable is configured to raise and lower the cradle upon the motor rotating the screw.

[0028] In another embodiment, each floating dock finger includes a middle channel. The first and second lift assemblies are positioned in the middle channels.

[0029] In another embodiment, the at least one cable extends downward from a midline of one of the floating dock fingers.

[0030] Another embodiment is a watercraft lift including a lift assembly, a vertically- extending track, a cradle, and at least one cable. The lift assembly includes a screw having a shaft and a helical thread and an electric motor configured to rotate the screw. The cradle is configured to vertically traverse the vertically-extending track. The at least one cable connects the cradle to the lift assembly. The at least one cable is configured to raise and lower the cradle upon the motor rotating the screw.

[0031] Another embodiment is a watercraft lift including a number of pilings, a dock finger, a lift assembly, a cradle, and at least one cable. The dock finger is supported on the pilings. The lift assembly is mounted to the dock finger and includes a lift tube, a screw, an electric motor, and a battery. The lift tube includes an internal chamber. The screw has a shaft and a helical thread. The electric motor is configured to rotate the screw. The battery powers the electric motor. The screw, the electric motor, and the battery are housed in the internal chamber of the lift tube. The cradle is suspended from the lift assembly. The at least one cable connects the cradle to the lift assembly and is configured to raise and lower the cradle upon the motor rotating the screw.

[0032] This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. Other aspects and advantages of the current invention will be apparent from the following detailed description of the embodiments and the accompanying drawing figures.Docket No. 61469-PCTBRIEF DESCRIPTION OF THE DRAWING FIGURES

[0033] Embodiments of the present invention are described in detail below with reference to the attached drawing figures, wherein:

[0034] FIG. l is a perspective view of a watercraft lift constructed in accordance with an embodiment of the invention;

[0035] FIG. 2 is a perspective view of certain components of the watercraft lift of FIG. 1;

[0036] FIG. 3 is an elevation view of certain components of the watercraft lift of FIG. 1; and

[0037] FIG. 4 is a perspective view of a component of the watercraft lift of FIG. 1;

[0038] FIG. 5 is an elevation view of a component of the watercraft lift of FIG. 1;

[0039] FIG. 6 is a perspective view of certain components of the watercraft lift of FIG. 1;

[0040] FIG. 7 is a perspective view of a component of the watercraft lift of FIG. 1;

[0041] FIG. 8 is an elevation view of certain components of the watercraft lift of FIG. 1;

[0042] FIG. 9 is an elevation view of certain components of the watercraft lift of FIG. 1;

[0043] FIG. 10 is an elevation view of certain components of the watercraft lift of FIG. 1;

[0044] FIG. 11 is an elevation view of certain components of the watercraft lift of FIG. 1;

[0045] FIG. 12 is a perspective view of certain components of the watercraft lift of FIG. 1 ;

[0046] FIG. 13 is a perspective view of certain components of the watercraft lift of FIG. 1;

[0047] FIG. 14 is a perspective view of certain components of the watercraft lift of FIG. 1;

[0048] FIG. 15 is a perspective view of certain components of the watercraft lift of FIG. 1;

[0049] FIG. 16 is a perspective view of certain components of the watercraft lift of FIG. 1;

[0050] FIG. 17 is a perspective view of certain components of the watercraft lift of FIG. 1;

[0051] FIG. 18 is a perspective view of certain components of the watercraft lift of FIG. 1 ;

[0052] FIG. 19 is an elevation view of certain components of the watercraft lift of FIG. 1;

[0053] FIG. 20 is an elevation view of certain components of the watercraft lift of FIG. 1;

[0054] FIG. 21 is an elevation view of certain components of the watercraft lift of FIG. 1;

[0055] FIG. 22 is a perspective view of certain components of the watercraft lift of FIG. 1;

[0056] FIG. 23 is a perspective view of certain components of the watercraft lift of FIG. 1 ;

[0057] FIG. 24 is a perspective view of certain components of the watercraft lift of FIG. 1;

[0058] FIG. 25 is a perspective view of certain components of the watercraft lift of FIG. 1;

[0059] FIG. 26 is a perspective view of certain components of the watercraft lift of FIG. 1 ;Docket No. 61469-PCT

[0060] FIG. 27 is a perspective view of certain components of the watercraft lift of FIG. 1 ;

[0061] FIG. 28 is a perspective view of certain components of the watercraft lift of FIG. 1;

[0062] FIG. 29 is a perspective view of certain components of the watercraft lift of FIG. 1 ;

[0063] FIG. 30 is a perspective view of certain components of the watercraft lift of FIG. 1 ;

[0064] FIG. 31 is a perspective view of certain components of the watercraft lift of FIG. 1;

[0065] FIG. 32 is an elevation view of certain components of the watercraft lift of FIG. 1;

[0066] FIG. 33 is a perspective view of certain components of the watercraft lift of FIG. 1;

[0067] FIG. 34 is a perspective view of certain components of the watercraft lift of FIG. 1;

[0068] FIG. 35 is a perspective view of certain components of the watercraft lift of FIG. 1 ;

[0069] FIG. 36 is a schematic diagram of certain components of the watercraft lift of FIG. 1;

[0070] FIG. 37 is a perspective view of a watercraft lift constructed in accordance with another embodiment of the invention;

[0071] FIG. 38 is a perspective view of certain components of the watercraft lift of FIG. 37;

[0072] FIG. 39 is a perspective view of certain components of the watercraft lift of FIG. 37;

[0073] FIG. 40 is a perspective view of certain components of the watercraft lift of FIG. 37;

[0074] FIG. 41 is a perspective view of certain components of the watercraft lift of FIG. 37;

[0075] FIG. 42 is a perspective view of a watercraft lift constructed in accordance with another embodiment of the invention;

[0076] FIG. 43 is a perspective view of a watercraft lift constructed in accordance with another embodiment of the invention;

[0077] FIG. 44 is a perspective view of certain components of the watercraft lift of FIG. 43;

[0078] FIG. 45 is a perspective view of certain components of the watercraft lift of FIG. 43;

[0079] FIG. 46 is an elevation view of certain components of the watercraft lift of FIG. 43;Docket No. 61469-PCT

[0080] FIG. 47 is a perspective view of certain components of the watercraft lift of FIG. 43;

[0081] FIG. 48 is a perspective view of a watercraft lift constructed in accordance with another embodiment of the invention;

[0082] FIG. 49 is a perspective view of certain components of the watercraft lift of FIG. 48;

[0083] FIG. 50 is an elevation view of certain components of the watercraft lift of FIG. 48;

[0084] FIG. 51 is a perspective view of a watercraft lift constructed in accordance with another embodiment of the invention;

[0085] FIG. 52 is an elevation view of a watercraft lift constructed in accordance with another embodiment of the invention;

[0086] FIG. 53 is an elevation view of the watercraft lift of FIG. 52; and

[0087] FIG. 54 is a perspective view of the watercraft lift of FIG. 52.

[0088] The drawing figures do not limit the current invention to the specific embodiments disclosed and described herein. The drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the invention.DETAILED DESCRIPTION

[0089] Turning to FIGS. 1-36, a watercraft lift 100 constructed in accordance with an embodiment of the invention will now be described. The lift 100 may be used in several configurations as described below, but will initially be described in an integrated lift and piling configuration. In this embodiment, a plurality of pilings 12 may be paired laterally to each other for supporting the lift 100. The lift 100 broadly comprises a cradle 102, one or more lift assemblies 104, a power supply 106 (FIG. 36), and a control system 108 (FIG. 36).

[0090] The cradle 102 supports a boat and may include opposing forward and rear crossbeams 110, 112, longitudinal bunks 114 extending between the forward and rear crossbeams 110, 112, bunk brackets 118 connecting the longitudinal bunks 114 to the forward and rear crossbeams 110, 112, and a crossbeam connector beam 116.

[0091] The forward and rear crossbeams 110, 112 may be spaced apart from each other and extend laterally towards lift tubes (described below) of the lift assemblies 104. The forwardDocket No. 61469-PCT and rear crossbeams 110, 112 may be substantially rigid to transfer weight of a boat to the lift assembly 104.

[0092] The longitudinal bunks 114 may be laterally spaced from each other and extend between (and in some cases beyond) the forward and rear crossbeams 110, 112. The longitudinal bunks 114 may also be spaced above the forward and rear crossbeams 110, 112 for supporting the boat.

[0093] The bunk brackets 118 connect the longitudinal bunks 114 to the forward and rear crossbeams 110, 112. The bunk brackets 118 may be adjustable for effecting a desired height of the longitudinal bunks 114.

[0094] The crossbeam connector beam 116 extends between the forward and rear crossbeams 110, 112 to prevent rotation of the forward and rear crossbeams 110, 112. Alternatively, the longitudinal bunks 114 may provide this structural rigidity, however in such a case the forward and rear crossbeams 110, 112 should be stabilized if the longitudinal bunks 114 are unbolted for adjustment. The crossbeam connector beam 116 may be reachable from a dock for safe installation.

[0095] The lift assemblies 104 raise and lower the cradle 102 and hence the boat. The lift assemblies 104 may be substantially similar so only one lift assembly 104 will be described in detail. The lift assembly 104 may include a lift tube 132, an electric motor 134, a gearbox 136, an electric brake 138, a screw 140, a nut 142, a nut carrier 144, a collar 146, a thrust bearing 148, a first pulley 150, a second pulley 152, a third pulley 154, a forward crossbeam connector 156, a rearward crossbeam connector 158, and a cable 162. The cable 162 will be described as part of the lift assembly 104 but can be considered more generally as part of the lift 100 and may be part of multiple lift assemblies.

[0096] Turning to FIGS. 8-13, the lift tube 132 may be supported by pilings 12 or by the dock beam 14 positioned to be at an inside edge of the dock 10, and shimmed such that the top of the lift tube 132 is near a top of the dock surface. This saves the need for four additional pilings for the lift 100 and reduces the gap between the boat and the dock 10. The lift tube 132 may have an internal chamber 164 configured to house the electric motor 134, the gearbox 136, the screw 140, a battery (described below) and related components. The lift tube 132 may be an extruded tube, which provides stability and torsional stiffness. The extruded tube may be machined (or subjected to other subtractive manufacturing) to create openings while leaving ribs, bridges, orDocket No. 61469-PCT other reinforcing structures (and hence retaining the stability and torsional stiffness). Machining or other subtractive manufacturing could also be used to reduce weight of the lift tube 132 without sacrificing stability and torsional stiffness. The lift tube 132 may further include holes 166 for receiving the cable 162 therethrough. The holes 166 may have soft radiused edges for pulling the cable 162 through without chaffing and giving a guiding surface for an index of a D-ring block (described below). The lift tube 132 may also include one or more lids 168 (FIGS. 9 and 19) bolted or otherwise connected to a top of the lift tube 132 for access to the internal chamber 164.

[0097] The electric motor 134 may be drivably connected to the gearbox 136 and may be a direct current (DC) brushless motor, which allows accurate speed control. Alternatively, an alternating current (AC) motor may be used, which eliminates the need for a battery. However, this would require a high amp circuit and would not be solar compatible. The electric motor 134 may also provide regenerative braking, which reduces battery size by approximately thirty-three percent. This in turn reduces lift tube width, height, and length. Regenerative braking also reduces the amps required for solar charging and increases the number of back-to-back lift cycles that can be achieved. The electric motor 134 may be enclosed in waterproof material or structure.

[0098] The gearbox 136 may be drivably connected between the electric motor 134 and the screw 140. The gearbox 136 may have a number of gearbox ratios (or continuous variability) for varying lifting capacity and lifting speed. An output shaft of the gearbox 136 may be connected to the screw via a coupling.

[0099] The electric brake 138 slows and stops rotation of the screw 140. The electric brake 138 may be incorporated into the electric motor 134 or the gearbox 136. The electric motor 134, gearbox 136, and electric brake 138 may be a submersible unit. The electric brake 138 may be released by being energized in an emergency down mode if the lift 100 fails to lower.

[0100] The screw 140 may be drivably connected to the gearbox 136 via a coupler 172 and supported in the lift tube 132 by a thrust bearing 174 mounted on a bulkhead 1 6 near one end and a bushing 178 on a mount 180 near the opposite end. Pulling force from the cable 162 is transmitted to the lift tube 132 through the thrust bearings 174.

[0101] The screw 140 may include helical threads 170 (FIG. 12) and in one embodiment, may be a ball screw. This provides high speed lifting, a relatively low power requirement, less heat build-up, and greater efficiency. A ball screw is also compatible with a controller that enables ramping up and ramping down for smoother operation. Alternatively, an Acme screw may be usedDocket No. 61469-PCT without a brake. However, Applicant has found Acme screws have several disadvantages. Some disadvantages of Acme screws include overheating of the corresponding nut, a requirement of several batteries which increases weight, high power usage, high amp draw which requires large cable feeds and more expensive controllers, relatively slow operation, and impractical manual cranking during “emergency down” operation.

[0102] Turning to FIG. 19, the nut 142 may be entrained on the screw 140 via threads for traversing the screw 140 longitudinally as the screw 140 rotates. The nut 142 may include ball bearings and a brake to prevent backdriving in the case of a ball screw. Alternatively, the nut 142 may be a solid construction in the case of an Acme screw. The nut 142 may be seated in the nut carrier 144 for transferring forces to and from the cable 162.

[0103] The nut carrier 144 engages the nut 142 (e.g., via bolts) and may include a number of cable grooves 182, a cable clamp 184, and a plurality of guides 186. The nut carrier 144 secures the cable 162 between its ends up to a set force before allowing the cable 162 to slip. This prevents the full load of the screw 140 from being transferred to a single side of the cable 162, thereby preventing cable breakage. Since the portion of the cable 162 extending on the reversing second pulley 152 (i.e., the longer portion) is approximately twice as long as the opposing portion of the cable 162 (i.e., the shorter portion), the longer portion stretches about twice as much as the short cable. This causes excessive loading on the shorter portion when the cradle 102 is unloaded and being lifted. To counter this (i.e., evening the load) the lift assembly 104 is set up with about a half of an inch spacer between the top of the crossbeam corresponding to the shorter portion and the bottom of the lift tube 132. Then the cradle 102 is lifted to the top position, and the cable 162 naturally adjusts in the nut carrier 144. The cable clamp 184 (described below) is then secured, and the spacer is removed.

[0104] The cable grooves 182 retain the cable 162 in position relative to the nut carrier 144. In one embodiment, the cable grooves 182 may be positioned on opposite sides of the cable clamp 184.

[0105] The cable clamp 184 secures the cable 162 to the nut carrier 144. In one embodiment, the cable clamp 184 is a plate configured to cinch against the cable 162 via bolts 190. The cable clamp 184 may be positioned between the cable grooves 182. In the case of a synthetic cable, since synthetic cable gets damaged when clamped, the cable clamp 184 may include a pin 192 and a reversing detail 194. The cable 162 is routed around the pin 192, around the reversingDocket No. 61469-PCT detail 194, and around the pin 192 again. This creates a locking ratio of about 5-20:1 such that 500-2,000 pounds would be required to shift the cable given the approximately 100 pounds of the supported portion of the empty cradle 102. With no slipping, this could theoretically allow an entire 10,000 pound force to be supported on a single cable portion for a lift with 20,000 pound capacity. In one embodiment, the synthetic cable 162 may self-adjust in the cable clamp 184.

[0106] The guides 186 may be positioned on the nut carrier 144 to take vertical loads and horizontal loads and react them with the lift tube 132 while sliding longitudinal relative to the lift tube 132. The guides 186 may be positioned to react equal and opposite horizontal and vertical loads on the screw 140 to prevent the screw 140 from bending. To that end, the guides 186 may be plastic, or other low friction material. In one embodiment, two guides 186 may be used. Alternatively, guide wheels may be used, which may be more complicated and costly.

[0107] The collar 146 may be positioned near an end of the screw 140 for providing a travel stop for the nut 142 via the thrust bearing 148. The collar 146 may be clamped onto the screw 140 via a set screw or similar means.

[0108] The thrust bearing 148 may be positioned near the collar 146. The thrust bearing 148 may be configured to engage the nut 142 and prevent further travel thereof on the screw 140, thereby establishing a lower / lowered position of the lift 100 and cradle 102. The thrust bearing 148 may also be configured to retain rotational freedom of the nut 142 relative to the thrust bearing 148 such that the nut 142 does not jam against the thrust bearing 148. That is, the nut 142 can back off the thrust bearing 148 with virtually no rotational friction therebetween.

[0109] The first pulley 150 may be oriented vertically (i.e., configured to rotate about a horizontally-extending axis) and may be positioned in the lift tube 132 over one of the forward and rearward crossbeams 110, 112. The first pulley 150 may be configured to redirect the cable 162 substantially ninety degrees downward to the associated crossbeam 110, 112.

[0110] The second pulley 152 may be oriented horizontally (i.e., configured to rotate about a vertically-extending axis) near the first pulley for redirecting the cable substantially one hundred and eighty degrees towards the third pulley 154. Note the cable 162 is clamped operationally between the first pulley 150 and the second pulley 152.

[0111] The third pulley 154 may be similar to the first pulley in that the third pulley 154 may be oriented vertically (i.e., configured to rotate about a horizontally-extending axis). The third pulley 154 may be positioned in the lift tube 132 opposite the first pulley 150 over the oppositeDocket No. 61469-PCT one of the forward and rear crossbeam 110, 1 12. The third pulley 154 may be configured to redirect the cable 162 substantially ninety degrees downward to the associated crossbeam.

[0112] Turning to FIGS. 2-7 and 14-18, the forward crossbeam connector 156 and the rearward crossbeam connector 158 may be substantially similar so only the forward crossbeam connector 156 will be described in detail. The forward crossbeam connector 156 connects the cable 162 to the forward crossbeam 110 and may include a D-ring block 196, a D-ring 198, a chain link 200, a pin 202, and a pin reinforcement block 204. This is particularly suitable for a synthetic cable. Alternative embodiments utilizing a stainless wire cable may omit the D-ring block 196, the D-ring 198, and the chain link 200.

[0113] The D-ring block 196 receives the cable 162 through an opening 206 therein. The D-ring block 196 also includes a pocket 208 and opposing slots 210, one of which includes an index 212. The slots 210 receive the D-ring 198 with the index 212 retaining the D-ring 198 in the slots 210. Opposite the pocket 208 may be indexing geometry 214 that extends around the opening 206 to keep the D-ring block 196 from sliding and cutting the cable 162.

[0114] The D-ring 198 may be secured to an end of the cable 162 and to the chain link 200. The D-ring 198 may be configured to engage the D-ring block 196 via the slots 210. The D-ring 198 is retained in the slots 210 via the index 212. The cable 162 prevents the D-ring 198 from laterally sliding out of the slots 210, while the D-ring can be manually removed as needed.

[0115] The chain link 200 connects the D-ring 198 (and hence the cable 162) to the pin 202. The chain link 200 may be a “removable link” for separating the cable 162 from the cradle 102. The chain link 200 may allow 2-axis motion without moving the cable 162 thereby limiting fatigue while enabling some motion of the hanging load.

[0116] The pin 202 extends between walls of the corresponding crossbeam connector and attaches the cable 162 (via the D-ring 198 and the chain link 200) to the cradle 102. The pin 202 may be reinforced by the pin reinforcement block 204 as described below, which allows a decreased pin diameter. This in turn allows for easier manufacturing and installation.

[0117] The pin reinforcement block 204 supports the pin 202 in a cavity of the corresponding crossbeam connector and includes opposing lugs 216, and opposing shoulders 218. In one embodiment, the pin reinforcement block 204 also includes a U-shaped or teardrop shaped groove 220. The lugs 216 include through-holes 222 for receiving the pin 202 therethrough. The shoulders 218 extend laterally outward from the lugs 216 for engaging the pin 202. The grooveDocket No. 61469-PCT220 extends around a bottom of the pin reinforcement block 204 and may be used for receiving a synthetic cable. In another embodiment, the groove 220 extends above the lugs 216. Synthetic cable is not suitable for looping around a small-diameter pin, so the groove 220 allows for a larger diameter loop in the end of the synthetic cable. This may be used instead of the D-ring block 196 and D-ring 198.

[0118] The pin reinforcement block 204 distributes loads from the cable 162 to the pin 202 more evenly. More specifically, the cable 162 exerts an upward force on a middle of the pin 202. The pin 202 in turn exerts an upward force on the lugs 216 of the pin reinforcement block 204. The pin reinforcement block 204 in turn exerts an upward force on the pin 202 nearer ends of the pin 202. In this way, a reduced bending moment is created on the pin 202 than if the pin reinforcement block 204 was omitted. The pin 202 can thereby have a reduced diameter. This may be desirable for adjusting the width of the crossbeam connectors, which requires hand-drilled pin holes.

[0119] The cable 162 may be a wire rope with a swaged end, a synthetic cable, or any other suitable cable. Generally speaking, the cable 162 extends from one crossbeam connector to the other crossbeam connector while being routed in and through the lift tube 132. More specifically, the cable 162 may extend vertically upward from the D-ring 198, through the D-ring block 196, turn ninety degrees at the first pulley 150, and continue horizontally to the nut carrier 144. The cable 162 may further continue through one of the guides 186 of the nut carrier 144 and encircling the nut carrier 144 to the cable clamp 184 where the cable 162 is secured to the nut carrier 144. The cable 162 may then continue encircling the nut carrier 144 (thereby reversing direction) through the opposing guide 186 and horizontally to the second pulley 152. The cable 162 may then pass around the second pulley and continue horizontally in another reversal of direction to the third pulley 154. The cable 162 may then turn ninety degrees at the third pulley and continue vertically downward through another D-ring block and to another D-ring. Alternatively, two separate cables can extend to the nut carrier or can be clamped together. However, a single cable simplifies assembly and adjustment. For example, the lift 100 can self-adjust by the cable 162 sliding at the cable clamp 184, which prevents cable overloading. In the case of a synthetic cable, the cable 162 may include one or more bullets 224 embedded in a core of the cable 162 as seen in FIG. 21, which can act as a bidirectional stop. Synthetic cable may also be more durable than stainless wire ropeDocket No. 61469-PCT in fatigue environments and is better for smaller pulley diameters. For many applications, use of synthetic cable is more compact than using steel wire cable.

[0120] The port and starboard (or left and right) lift assemblies 104 may be mirror images about a centerline of the cradle 102. This allows the cradle 102 to be loaded symmetrically and evenly, since the cables do not exit the respective lift tubes 132 on centerlines of the lift tubes 132.

[0121] Turning to FIG. 36, the power supply 106 provides power to the lift assembly 104 and may include a battery 226 and a charger 228. In some embodiments, the power supply 106 may power multiple lift assemblies and even multiple lifts.

[0122] The battery 226 provides DC power to the electric motor 134, the controller 232, and other electric or electronic components. To that end, the battery 226 may be connected to such components via battery wire 230 and may be positioned in the lift tube 132 or in a remote control panel (see FIG. 9, for example). Having the battery next to the motor reduces the length and gauge of heavy gauge wire. The battery 226 may include a plug for charging via generator or line power. The battery 226 may also be enclosed in waterproofing material such as shrink-wrap plastic regardless of location. Several innovations described here, such as the use of regenerative braking, have reduced the battery size to be suitable for installation in the lift tube 132 and have even reduced the size of the lift tube 132. The battery 226 may be electrically connected to a battery of the other lift assembly via a battery wire 230 to ensure equal charge level between the batteries. The battery wire 230 may be bundled with control wires (described below) and enclosed in a guide chain 244 for protection.

[0123] The charger 228 may be an AC trickle charger, a solar panel, or a combination thereof. The charger 228 may be mounted externally from the lift tube 132, such as in the control box 234. This allows the charger 228 to be closer to an AC outlet and allows the charger 228 to be easily removable before a flooding event. Mounting the charger 228 externally also reduces the length of the lift tube 132. Regenerative braking adds significant charge while lowering the cradle 102, which enables a much smaller battery and less battery charging. The charger 228 may be configured to not fully charge the battery 226 such that the battery 226 does not get overcharged when lowering and using regenerative charging.

[0124] With reference again to FIG. 36, the control system 108 controls operation of the lift 100 and may include a controller 232, a control box 234, a remote controller 236, and a plurality of inputs 238. In some embodiments, the control system 108 may control multiple lifts.Docket No. 61469-PCT

[0125] The controller 232 activates the electric motor 134 in response to remote control signals and may be positioned in the lift tube 132 and even included in the electric motor 134 so the controller 222 can be inside a water resistant casing, and wires can be concealed. The controller 232 may be set to operate the electric motor 134 at a constant or predetermined RPM (or according to a predetermined RPM curve) regardless of the load. This eliminates the need to keep the boat centered for level lifting. The controller 232 may also limit maximum torque, which limits overloading the lift, thereby providing additional safety. The controller 232 may be configured to deactivate (stop) the electric motor 134 when a set maximum torque is reached or any other suitable condition is met. In this way, any slight difference in the level of the cradle 102 is corrected at the top position. This eliminates the need for encoders and sensors. The controller 232 may ramp up to speed and decelerate when stopping for smooth operation. The controller 232 of left and right lift assemblies 104 may be communicatively connected via control wires 242 to lift and lower both lift assemblies 104 at the same time.

[0126] Turning to FIG. 20, the control wires 242 may be attached to the nut 142 (FIG. 19), routed to a hole in the bottom of the lift tube 132, through one of the crossbeams 110, 112, up through a hole in the opposite lift tube 132, and attached to the nut of the opposite lift tube 132 such that the control wires 242 are retractable. Slack should be removed from the control wires 242 by securing extra portions via cable ties and storing this excess in the crossbeam. This keeps the control wires 242 out of the water when the lift 100 is in the up position. The control wires 242 may be bundled with the battery wire 230 and enclosed in a guide chain 244 (FIG. 36) for protection. This prevents the control wires and the battery wire 230 from getting pinched or damaged.

[0127] The control box 234 may be an external station that provides easier access to an operator. The control box 234 may be mounted on a dock or similar structure within approximately fifteen feet of the lift tube 132. The control box 234 may house the remote controller 236, the charger 228, and other electrical or electronic components.

[0128] The remote controller 236 directs lift and lower commands from the inputs 238, an application on a remote operator device 20, or a transmitter to the lift tubes 132 via the controller 232 and may be mounted in the control box 234. The inclusion of a remote controller 236 provides easier access to an operator and eliminates the need for a locking door access in the lift tube 132. The remote controller 236 may also have a security feature that disables the inputs 238 so that theDocket No. 61469-PCT lift 100 can only be operated via the application on the remote operator device 20, which eliminates the need for a locking door on the control box 234. The remote controller 236 may include two wire harnesses — one wire harness to control the port side of the lift 100 and another wire harness to control the starboard side of the lift 100. A third wire harness may be included for charging and operation of an optional automatic boat cover.

[0129] Turning to FIGS. 22 and 23, in another embodiment, the lift tube 132 may include geometry 300 on or near its lower side for engaging a universal piling mount 302 having one or more clips 304, a vertically oriented orthogonal (e.g., square) tube 306, and an angle bracket 308. The geometry 300 may be a flange, a lip, a tab, a protrusion, a groove, a recess, a slot, a hole, or the like. The clips 304 may be configured to be bolted onto the orthogonal tube 306 and securely grasp the lift tube 132. The angle bracket 308 connects the orthogonal tube 306 to the piling 12. This enables the angle bracket 308 to be positioned off-center relative to the piling 12 but with the clips 304 aligned to the lift tube 132.

[0130] Turning to FIGS. 24-27, in another embodiment, it may be desirable for the lift tube 132 to be installed near or at dock level to keep out of view and for easier boarding. However, this limits the lifting height, which can be a problem during storm surges. To enable increased lifting height such as before a storm surge, the lift tube 132 may mounted to the piling 12 via a telescoping pile mount 400 including a lower tube 402 and an upper tube insert 404. The lower tube 402 may include welded tabs 406 for bolting the lower tube 402 to the piling 12. The lower tube 402 may be configured to accept the upper tube insert 404. The upper tube insert 404 may be attached to the lift tube 132 via the above-described universal piling mount 302. For additional lifting range, the bunks 114 can be raised by using insert risers in the bunk brackets 118. To ease raising and lowering the bunks 114, a come-along or other pulling or pushing device may be used.

[0131] Turning to FIGS. 28 and 29, in another embodiment, an existing dock piling 500 may be used instead of driving a new piling. To that end, a side bracket 502 may be installed to support the lift tube 132. The side bracket 502 may include a vertical member 504, a horizontal member 506, a bar 508, and an orthogonal (e.g., square) tube 510. The vertical member 504 may be bolted to the piling 500 or a bulkhead. The horizontal member 506 may extend cantilever from the vertical member 504 toward a middle of the boat slip. The bar 508 may be bolted to the horizontal member 506. The orthogonal tube 510 may be welded to the bar 508 and bolted to the clip 304 of the above-described universal piling mount 302 thereby engaging and supporting theDocket No. 61469-PCT lift tube 132. The horizontal member 506 may be a tube such that another tube can be inserted therein to provide additional length and to enable the lift tube 132 to be slid out for service if the top of the lift tube 132 cannot be accessed.Platform Configuration

[0132] Turning to FIGS. 30-35, in a platform configuration, a third crossbeam 600 can be added to the lift 100 (with one of the previously-described forward and rear crossbeams 110, 112 being a middle crossbeam) to enable a platform 602 to be added that extends near the bow of the boat. The port and starboard ends of the third crossbeam 600 may be lifted via an additional cable 604, which may be clamped to the cable 162 near the nut 142. The additional cable 604 may extend past the pulley 150 to a fourth pulley 606 that directs the additional cable 604 downward to the third crossbeam 600. Structural channels may extend fore and aft of the third crossbeam 600 to support decking on the platform.Floating Configuration

[0133] Turning to FIGS. 37-42, in a floating configuration, a lift 100 may have port and starboard lift assemblies 104 mounted in a middle channel 700 of port and starboard floating dock fingers 702. The lift assemblies 104 may be positioned such that the cables 162 extend downward on a centerline of the corresponding dock finger 702 to effect a balanced load. Each dock finger 702 may be attached to a main dock 10 by a ramp 704 which allows the dock finger 702 to translate up and down. The floating dock fingers 702 may be stabilized by pilings 12, an underwater yoke 18 (FIG. 42) connecting the floating dock fingers 702 together, or via ramps with torsional stiffness. If multiple lifts are used at one location, such as at a marina, boat slips with a lift 100 may be separated by an empty space (e.g., a boat slip without a lift) so that the floating dock fingers 702 can translate up and down without impacting neighboring boats. As seen in FIGS. 39-41, in one embodiment, the floating dock fingers 702 may be constructed of plastic modular sections connected with rubber unions. A hollow plastic filler member 706 may fill in the middle channel 700 of floating dock fingers 702 with no lift assembly installed. The cable 162 may be self- adjusting for balancing the lift 100. The cable 162 may include a bullet as described above to limit slip therein.Floating Covered Marina ConfigurationDocket No. 61469-PCT

[0134] In a floating covered marina configuration, a roof structure or underwater truss distributes vertical load of floating dock fingers to keep elevations of the floating dock fingers similar to elevations of neighboring floating dock fingers and of a main dock.Freestanding Configuration

[0135] Turning to FIGS. 43-47, in a freestanding configuration, a watercraft lift 100 includes opposing lift assemblies 104 (each with a lift tube 132), a cradle 102, a frame 800, and a control system 108. The frame 800 may be freestanding and may include four or more uprights, fore and aft members and side-to-side members connecting the uprights. The uprights may be telescoping or otherwise adjustable for changing a height of the watercraft lift 100. The fore and aft members and / or side-to-side members ay also be telescoping or otherwise adjustable for changing a width of the frame 800.

[0136] In one embodiment, only one of the opposing lift tubes 132 includes a ball screw 140, a battery 226, an electric motor 134, a controller 232, a gearbox 136, an electric brake 138, a nut 142, and a nut carrier 144. The control system 108 includes a control box 234, a remote controller 236, and a charger 228 (AC and / or solar charger). The watercraft lift 100 further includes a single continuous synthetic cable 162 secured near the cable’s midsection to the nut carrier 144. One end of the cable 162 may be routed horizontally in the lift tube 132 to a first pulley 802, directing the cable 162 to a first section 804, which leads downward to an inboard side of a rear crossbeam 806 of the frame 800. The cable 162 may be secured to the rear crossbeam 806 via a short bullet 808 that expands to a diameter of the cable 162 and locks into a stopper plate 810 on the rear crossbeam 806. A chamfer in a hole 812 in the stopper plate 810 matches a chamfer of the bullet 808 to minimize stress concentration. The cable 162 continues downward in a second section 814 to a second pulley 816 at a level of a lower cross tube 818. The second pulley 816 directs the cable 162 horizontally defining a third section 820, routing the cable 162 along the cross tube 818 to a third pulley 822 on an opposite comer of the frame 800. The third pulley 822 directs the cable 162 upward defining a fourth section 824 and leading to a fourth pulley 826 in the far side lift tube 132 supported by a telescoping upright 828. The fourth pulley 826 reverses direction of the cable 162, leading the cable 162 downward to a fifth section 830 to a turning bracket 832 attached to the crossbeam 806. The turning bracket 832 directs the cable 162 horizontally inside the crossbeam 806 thereby defining a sixth section 834. This terminates the cable 162 with a loop around a termination mount 836 bolted to the crossbeam 806. The termination mount 836 may have severalDocket No. 61469-PCT holes for adjustment in the termination mount 836 and in the crossbeam 806. As mentioned above, the frame 800 may have an adjustable width. To that end, additional holes spaced approximately six inches apart may be added for the turning bracket 832 and for the cross tube 818 to make narrowing the frame 800 easier by cutting the crossbeam 806 and the cross tube 818 equally by six inch (for example) increments. Furthermore, a height and a lifting range of the lift assemblies 104 may be adjustable via the frame 800. In addition, the cable 162 may be adjustable (with fine tune adjustments) for port / starboard and / or forward / rearward balancing.Fixed Dock Configuration

[0137] Turning to FIGS. 48-50, in a fixed dock configuration, the watercraft lift 100 may be integrated into a fixed dock 10. Horizontal dock beams 14 may be connected near tops of pilings 12 to support dock joists 16. In this configuration, each boat slip of the dock 10 may include a watercraft lift 100. Because the fingers of the dock 10 are fixed, raising and lowering one watercraft lift 100 will not affect the adjacent watercraft lift 100.Catamaran Configuration

[0138] Turning to FIG. 51, in a catamaran configuration, a catamaran 900 may have opposing port and starboard hulls 902 each including an outboard motor 904 for propulsion and steering. Each hull 902 may have a lift assembly 104 including a lift tube 132. Each lift assembly 104 may be configured to pull on two cables 906 connected to crossbeams. Bunks 910 attached to the crossbeams support a boat being lifted. A lifting platform 912 can be added to better access the bottom of the boat being lifted and to reinforce the port and starboard hulls 902. The hulls 902 may be attached with an overhead arch 914 configured to enable the bow of the boat being lifted to clear underneath.Elevator Configuration

[0139] Turning to FIGS. 52-54, in an elevator configuration, a substantially horizontal lift assembly 100 may be attached to dock similar to some of the above-described embodiments. The lift assembly 100 and one or more associated cables attach to at least two carriages 1000 translating on vertically-extending tracks 1002. Each carriage 1000 may have a substantially horizontal crossbeam 1004 extending cantilevered from the carriage 1000. Boat bunks may be attached to the crossbeams 1004. In one embodiment, a single screw may be used with two cables for lifting and lowering the carriage(s) 1000. In another embodiment, two screws may be used with four cables for lifting and lowering the carriage(s) 1000.Docket No. 61469-PCTAdditional Considerations

[0140] Throughout this specification, references to “one embodiment”, “an embodiment”, or “embodiments” mean that the feature or features being referred to are included in at least one embodiment of the technology. Separate references to “one embodiment”, “an embodiment”, or “embodiments” in this description do not necessarily refer to the same embodiment and are also not mutually exclusive unless so stated and / or except as will be readily apparent to those skilled in the art from the description. For example, a feature, structure, act, etc. described in one embodiment may also be included in other embodiments, but is not necessarily included. Thus, the current invention can include a variety of combinations and / or integrations of the embodiments described herein.

[0141] Although the present application sets forth a detailed description of numerous different embodiments, it should be understood that the legal scope of the description is defined by the words of the claims set forth at the end of this patent and equivalents. The detailed description is to be construed as exemplary only and does not describe every possible embodiment since describing every possible embodiment would be impractical. Numerous alternative embodiments may be implemented, using either current technology or technology developed after the filing date of this patent, which would still fall within the scope of the claims.

[0142] Throughout this specification, plural instances may implement components, operations, or structures described as a single instance. Although individual operations of one or more methods are illustrated and described as separate operations, one or more of the individual operations may be performed concurrently, and nothing requires that the operations be performed in the order illustrated. Structures and functionality presented as separate components in example configurations may be implemented as a combined structure or component. Similarly, structures and functionality presented as a single component may be implemented as separate components. These and other variations, modifications, additions, and improvements fall within the scope of the subject matter herein.

[0143] As used herein, the terms “comprises”, “comprising”, “includes”, “including”, “has”, “having”, or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a process, method, article, or apparatus that comprises a list of elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.Docket No. 61469-PCT

[0144] The patent claims at the end of this patent application are not intended to be construed under 35 U.S.C. § 112(f) unless traditional means-plus-function language is expressly recited, such as “means for” or “step for” language being explicitly recited in the claim(s).

[0145] Although the technology has been described with reference to the embodiments illustrated in the attached drawing figures, it is noted that equivalents may be employed and substitutions made herein without departing from the scope of the technology as recited in the claims.

[0146] Having thus described various embodiments of the technology, what is claimed as new and desired to be protected by Letters Patent includes the following:

Claims

Docket No. 61469-PCTCLAIMS1. A watercraft lift comprising: opposing first and second lift assemblies each including: a screw having a shaft and a helical thread; and an electric motor configured to rotate the screw; a cradle suspended from the first and second lift assemblies, the first and second lift assemblies being synchronized thereby balancing the cradle; and at least one cable connecting the cradle to the first and second lift assemblies, the at least one cable being configured to raise and lower the cradle upon the motor rotating the screw.

2. The watercraft lift of claim 1, wherein each lift assembly further includes a lift tube having an internal chamber, and wherein the screw and the electric motor are housed in the internal chamber of the lift tube.

3. The watercraft lift of claim 2, wherein the cradle includes a crossbeam configured to index to a bottom of each lift tube for minimizing or eliminating sway of the cradle.

4. The watercraft lift of claim 2, wherein the screw is a ball screw, and wherein each lift assembly further includes: a nut connected to the at least one cable and configured to longitudinally traverse the screw when the screw is rotated; and a nut brake configured to prevent backdrive of the nut.

5. The watercraft lift of claim 1, each lift assembly further including a battery configured to power the electric motor, wherein the electric motor is a direct current (DC) motor, and wherein the electric motor is configured to regeneratively charge the battery when the cradle is lowered.Docket No. 61469-PCT6. The watercraft lift of claim 5, wherein each lift assembly further includes a lift tube having an internal chamber, and wherein the battery is positioned in the internal chamber of the lift tube.

7. The watercraft lift of claim 4, wherein each lift assembly further includes a brake, and wherein each lift assembly is configured to lower the cradle in an emergency down mode upon release of the brake.

8. The watercraft lift of claim 1, wherein each lift assembly further includes: a nut connected to the at least one cable and configured to longitudinally traverse the screw when the screw is rotated; a stopping collar; and a thrust bearing positioned on the screw near the stopping collar and configured to engage the nut thereby preventing the nut from sticking to the stopping collar.

9. The watercraft lift of claim 1, wherein each lift assembly further includes: a nut configured to longitudinally traverse the screw when the screw is rotated; and a cable clamp configured to secure the at least one cable to the nut such that opposing ends of the at least one cable extend to the cradle, the at least one cable being configured to self-adjust in the cable clamp by slipping in the cable clamp when a pre-determined load is reached thereby preventing the at least one cable from being overloaded.

10. The watercraft lift of claim 1, wherein each lift assembly further includes: a nut configured to longitudinally traverse the screw when the screw is rotated; and a cable retaining means connected to the nut and configured to secure the at least one cable to the nut such that opposing ends of the at least one cable extend to the cradle, the at least one cable being configured to self-adjust in the nut when one end of the at least one cable is loaded more than the opposing end of the at least one cable by a predetermined ratio.Docket No. 61469-PCT11 . The watercraft lift of claim 9, wherein a first portion of the at least one cable extending from the nut is longer than a second portion of the at least one cable extending from the nut, and wherein the first portion is pre-loaded a greater amount than the second portion when the cradle is in a home position to reduce a load on the second portion.

12. The watercraft lift of claim 1, wherein the cradle includes a middle crossbeam and a rearward crossbeam configured to support a watercraft and a forward crossbeam configured to support a platform, the at least one cable being connected to the middle crossbeam, the watercraft lift further comprising an additional cable connected to the forward crossbeam and the at least one cable.

13. The watercraft lift of claim 1, wherein the electric motor of the first lift assembly and the electric motor of the second lift assembly are constant RPM motors thereby synchronizing the first and second lift assemblies for controlling a side-to-side level of the cradle.

14. The watercraft lift of claim 13, wherein the first lift assembly and the second lift assembly are configured to automatically relevel the cradle when the cradle is in a home position.

15. The watercraft lift of claim 1, the watercraft lift further comprising: a control system including a control wire communicatively connected to at least one of the electric motors of the first lift assembly and the second lift assembly, the at least one cable including a first cable connecting the cradle to the first lift assembly and a second cable connecting the cradle to the second lift assembly, at least one of the first lift assembly and the second lift assembly further including a nut connected to one of the first and second cables, the control wire being secured to the nut for lifting the control wire out of the water when the first lift assembly and the second lift assembly raise the cradle.

16. The watercraft lift of claim 1, wherein the cradle includes a forward crossbeam, a rear crossbeam, and a crossbeam connector configured to prevent rotation of the forward crossbeam and the rear crossbeam.Docket No. 61469-PCT17. The watercraft lift of claim 1, wherein the electric motor is a submersible motor including a controller and a gearbox, the watercraft lift further comprising a submersible battery configured to power the electric motor.

18. The watercraft lift of claim 1, wherein each lift assembly further includes: a lift tube having an internal chamber; a nut connected to the at least one cable and configured to longitudinally traverse the screw when the screw is rotated; and a nut carrier including: a plurality of guides entraining the nut in the internal chamber; a groove configured to receive the at least one cable therein; and a cable clamp configured to secure the at least one cable to the nut carrier.

19. The watercraft lift of claim 1 , further comprising a pin and a pin reinforcer, wherein the cradle includes a tubular member, the at least one cable being connected to the cradle via the pin, the pin reinforcer being configured to distribute bending forces in the pin, and wherein the pin reinforcer includes geometry for accepting a rope loop and geometry for accepting a cable eye.

20. The watercraft lift of claim 1, wherein the at least one cable is a synthetic cable including a bullet embedded therein and configured to engage one of the first and second lift assemblies thereby limiting movement of the cradle.Docket No. 61469-PCT21. A bracket assembly configured to secure a horizontal watercraft lift beam to a piling, the bracket assembly comprising: a clip configured to be attached to the watercraft lift beam; a central mounting structure, the clip being secured to the central mounting structure; and a pile mounting bracket configured to be mounted to the piling, the central mounting structure and hence the clip being configured to pivot relative to the pile mounting bracket.Docket No. 61469-PCT22. A telescoping bracket for raising a watercraft lift on a plurality of pilings, the telescoping bracket comprising: a lower tube configured to be mounted to one of the plurality of pilings; and an upper tube configured to be attached to the watercraft lift, the upper tube being configured to translate vertically relative to the lower tube.Docket No. 61469-PCT23. A watercraft lift comprising: a frame including a plurality of vertically-extending legs and a crossbeam connecting at least some of the plurality of vertically-extending legs; opposing first and second lift assemblies mounted on the frame, at least one of the first and second lift assemblies including: a screw having a shaft and a helical thread; and an electric motor configured to rotate the screw; a cradle supported by the first and second lift assemblies, the first and second lift assemblies being synchronized thereby balancing the cradle; and at least one cable suspending the cradle from the first and second lift assemblies and extending between the first and second lift assemblies via the crossbeam of the frame, the at least one cable being configured to raise and lower the cradle upon the motor rotating the screw.Docket No. 61469-PCT24. A watercraft lift comprising: opposing floating dock fingers; opposing first and second lift assemblies, each being mounted on one of the opposing floating dock fingers and including: a screw having a shaft and a helical thread; and an electric motor configured to rotate the screw; a cradle suspended from the first and second lift assemblies, the first and second lift assemblies being synchronized thereby balancing the cradle; and at least one cable connecting the cradle to the first and second lift assemblies, the at least one cable being configured to raise and lower the cradle upon the motor rotating the screw.

25. The watercraft lift of claim 24, wherein each floating dock finger includes a middle channel, and wherein the first and second lift assemblies are positioned in the middle channels.

26. The watercraft lift of claim 25, wherein the at least one cable extends downward from a midline of one of the floating dock fingers.Docket No. 61469-PCT27. A watercraft lift comprising: a lift assembly including: a screw having a shaft and a helical thread; and an electric motor configured to rotate the screw; a vertically-extending track; a cradle configured to vertically traverse the vertically-extending track; and at least one cable connecting the cradle to the lift assembly, the at least one cable being configured to raise and lower the cradle upon the motor rotating the screw.Docket No. 61469-PCT28. A watercraft lift comprising: a plurality of pilings; a dock finger supported on the plurality of pilings; a lift assembly mounted to the dock finger and including: a lift tube including an internal chamber; a screw having a shaft and a helical thread; an electric motor configured to rotate the screw; and a battery powering the electric motor, wherein the screw, the electric motor, and the battery are housed in the internal chamber of the lift tube; a cradle suspended from the lift assembly; and at least one cable connecting the cradle to the lift assembly, the at least one cable being configured to raise and lower the cradle upon the motor rotating the screw.

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