Watercraft Lift

This application is a continuation of U.S. patent application Ser. No. 18/597,736, filed Mar. 6, 2024, and is a continuation of U.S. patent application Ser. No. 17/324,059, filed May 18, 2021, issued as U.S. Pat. No. 11,932,364, issued Mar. 19, 2024, and claims the benefit of U.S. Provisional Patent Application No. 63/026,618, filed May 18, 2020, the disclosures of which are incorporated herein by reference in their entirety.

The present invention is directed to a freestanding watercraft lift, and more specifically, to a freestanding watercraft lift, such as a boat lift, which has a frame with typically four feet supported by the seabed, and translating bunks that support a watercraft and are lifted by pivoting arms.

There are a number of advantages to storing a boat out of the water when not in use. Out-of-water storage prevents damage resulting from the boat bumping against adjacent docks, other watercraft or floating debris. It reduces the possibility of the boat breaking free from its moorage and either floating away or running aground. Out-of-water storage also lessons boat damage associated with long-term exposure to water (e.g., corrosion electrolysis, rusting, and blistering), and the attachment of barnacles and other marine growth on the bottom of the boat.

Examples of prior art hydraulic boat lifts are shown in U.S. Pat. Nos. 5,908,264, 6,976,442, 7,246,970, 6,830,410, and 8,911,174, and U.S. Patent Application Publication No. 2014/0017009. This style boat lift has the boat supported by two laterally spaced apart bunks. The bunks are attached to at least two pivotally movable H-frames, which are pivotally attached to a lower frame and connected to one end of one or more hydraulic cylinders, which provide pivotal drive to the H-frames. The other end of the hydraulic cylinders is typically connected to a hydraulic beam of the lower frame, which extends laterally between left and right lateral beams of the lower frame. Other examples of prior art of hydraulic cushioning are U.S. Pat. Nos. 845,827, 2,642,845, and 2,719,510.

Some boat lift designs allow for lateral adjustment of the bunks of boat lift. However, these designs add significant complexity, weight and cost. Other concerns are installation time, durability, maintenance and aesthetics.

The invention generally relates to a watercraft lift system generally used for lifting powerboats, however, the design could be applied to other type boat and watercraft lift systems and other type boats and watercraft. U.S. Pat. No. 8,911,174 and U.S. Patent Application Publication No. 2014/0017009 are incorporated herein by reference in their entirety.

A first embodiment of the watercraft liftof the present invention is illustrated inand in subsequent figures, with several other embodiments also being illustrated with constructions somewhat similar to the embodiment of. As illustrated inshowing the watercraft liftin a fully raised position, the watercraft lift includes a substantially rectangular lower framecomprised of rearward lateral beamat a rearward endof the watercraft lift and a forward lateral beamat a forward endof the watercraft lift. The lower framefurther includes a longitudinal left side beamwith a rearward end portionA and a forward end portionB, and a longitudinal right side beamwith a rearward end portionA and a forward end portionB.

The longitudinal left side beamcomprises a left side forward beam portionand a left side rearward support member. The left side forward beam portionhas a rearward end portionA and a forward end portionB, and the left side rearward support memberhas a rearward end portionA and a forward end portionB.

The longitudinal right side beamcomprises a right side forward beam portionand a right side rearward support member. The right side forward beam portionhas a rearward end portionA and a forward end portionB, and a right side rearward support memberhas a rearward end portionA and a forward end portionB.

The rearward end portionA of the left side rearward support memberand the rearward end portionA of the right side rearward support memberare supported by the rearward lateral beam. The forward end portionB of the left side forward beam portionand the forward end portionB of the right side forward beam portionare supported by the forward lateral beam. The forward end portionB of the left side rearward support memberis rigidly attached to the rearward end portionA of the left side forward beam portion, and the forward end portionB of the right side rearward support memberis rigidly attached to the rearward end portionA of the right side forward beam portion. The left side rearward support memberis in longitudinal alignment with the left side forward beam portion, and the right side rearward support memberis in longitudinal alignment with the right side forward beam portion.

The lower frameis supported by four legs, each of which has a substantially circular or oval footpositionable on the seabed. It is to be understood that the footmay have other shapes.

An H-shaped rearward lifting frameand an H-shaped forward lifting frameare pivotally connected to the lower framefor raising and lowering a left side bunkand a right side bunk, or other style watercraft support members or platforms. The rearward lifting framecomprises a left side rearward lifting arm, a right side rearward lifting arm, and a rearward connector member, and the forward lifting framecomprises a left side forward lifting arm, a right side forward lifting arm, and a forward connector member. The rearward connector memberextends between and is connected to the left side rearward lifting armand a right side rearward lifting arm. Similarly, the forward connector memberextends between and is connected to the left side forward lifting armand the right side forward lifting arm.

In the preferred embodiment, the rearward and forward connector members are a tube, which is bolted to an open channel shape connected to the arms. In an alternate embodiment, the rearward and forward connector members are channels, connected to either channels or tubes, connected to the arms. This enables the connector member to be easily removed, verses a telescoping shape that can easily jam, especially if adjusting needs to be synchronized between multiple telescoping tubes. It is preferred to have the connector member to be a tube, since a tube is efficient in torsion, which keeps the left and right sides of the lift synchronized. In another alternate embodiment, a lateral member is connected to the inside of the right arms, and another lateral member is connected to the inside of the left arms. The left and right lateral members are bolted together in a plurality of possible positions that would provide various distances between the arms.

A lower end portionA of the left side rearward lifting armis pivotally connected to the left side rearward support memberwith a pivot axis at a location toward but forward of the rearward lateral beam, and an upper end portionB is pivotally connected to a rearward portionA of the left side bunk. A lower end portionA of the right side rearward lifting armis pivotally connected to the right side rearward support memberwith a pivot axis at a location toward but forward of the rearward lateral beam, and an upper end portionB is pivotally connected to a rearward portionA of the right side bunk.

Similarly, a lower end portionA of the left side forward lifting armis pivotally connected to the forward end portionB of the left side forward beam portionof the longitudinal left side beamwith a pivot axis at a location forward of or adjacent to the forward lateral beamand higher than an upper side of the longitudinal left side beam (i.e., at an elevation above the upper side), and an upper end portionB is pivotally connected to a forward portionB of the left side bunk. A lower end portionA of the right side forward lifting armis pivotally connected to the forward end portionB of the right side forward beam portionof the longitudinal right side beamwith a pivot axis at a location forward of or adjacent to the forward lateral beamand higher than an upper side of the longitudinal right side beam (i.e., at an elevation above the upper side), and an upper end portionB is pivotally connected to a forward portionB of the right side bunk. The pivotal connection of the left and right side forward lifting armsandto the left and right side forward beam portionsandalong a pivot axis at a location forward of the forward lateral beamenables the watercraft liftto be used in shallower water when facing an upward slope on the seabed, since moving the forward feetand forward lateral beamrearward enables rest of the lift to be installed further forward in shallower water. The described pivotal connections are preferably made using pivot pins.

The pivotal connections of the lifting arms,,andto the left and right side rearward support membersand, to the longitudinal left and right side forward beam portionsand, and to the left and right side bunksand, are preferably accomplished using corresponding through holes in the components to be pivotally connected together sized to receive pivot pins.

shows the watercraft liftin a fully lowered position. The left and right side bunksandare sloped rearward to assist in stopping forward movement of a watercraft “W” when being loaded on the watercraft lift. The slope is also necessary when using the hydraulic actuatorsandonly in the rear, since the hydraulic actuators produce load that is transferred to the left and right side rearward lifting armsand, then along the left and right side rearward support membersand. The left and right side rearward support membersandpush on the upper pivots of the left and right side forward lifting armsandand create a moment centered around the lower pivots of the left and right side forward lifting arms. The loads and required cylinder pressure decrease the higher the elevation of the upper pivots of the left and right side forward lifting armsand. In the preferred embodiment, it is desirable to have a small slope at the fully raised position to assist with drainage inside the watercraft “W,” and a larger slope in the fully lowered position to assist with docking, and to minimize the loads. Too much slope in the fully lowered position can increase the minimum required water depth.

shows the watercraft liftin a fully raised position and supporting the watercraft “W” on the bunksand, andshows the watercraft lift in a fully lowered position and supporting the watercraft on the bunks. As will be explained in greater detail below, inthe watercraft liftis shown using an alternative manner of connecting each footto the lower framethat allows use of the watercraft lift in shallower water.

The right side support membersandare best to be flexible enough to conform to most boat shapes, but stiff enough to spread the load evenly to a hull of a watercraft.

As shown in, each of the lifting arms,,, andmay include a lower arm member “L” with an open upper end portion sized to telescopically receive therein a lower end portion of an upwardly adjustably extendable telescoping upper arm member “U.”is an enlarged view of the left side rearward lifting armand illustrates that the lower arm member of each lifting arm has a through hole and the telescoping upper arm member has a plurality of longitudinally spaced apart through holes, with the through holes sized to receive a bolt or pinto secure the upper arm member at an adjustable desired extension out of the lower arm member. Once an upward extension is selected for the telescoping upper arm member relative to the lower arm member in which positioned and from which it is projecting, the bolt or pin is used to hold the telescoping upper arm member relative to the lower arm member in the extended position selected during use of the watercraft lift.

Using telescoping lifting arms,,, and, the upper end portion of the telescoping upper arm member “U” are pivotally connected to the left and right side bunksand. The use of telescoping lifting arms,,, andto effectively lengthen the lifting arms permits adjustment of the lifting range of the rearward and forward lifting framesand, and hence the vertical position of the left and right side bunksandrelative to the lower framewhen in the raised position. A similar adjustable range feature is described in U.S. Pat. No. 6,976,442, which is incorporated herein by reference in its entirety. It is to be understood that while the telescoping upper arm member “U” is illustrated as extending from within the lower arm member “L,” the telescoping lifting arms may be designed with the upper arm member receiving an upper end portions of the lower arm member within an open lower end portion of the upper arm member.

An alternative means of reducing the lifting range of the rearward and forward lifting framesandmay be achieved by cutting off the same amount of an upper portion of each of the upper arm members “U” of the lifting arms,,, and(at a location below the original through holes for their connection to the left and right bunksand), and drilling new through holes by which the upper arm members are to be pivotally connected to the left and right bunks, or by providing a secondary set of through holes predrilled below the original upper set.

As illustrated in, the watercraft liftincludes a left side dual-directional hydraulic actuatorand a right side dual-directional hydraulic actuator. Each of the left and right side hydraulic actuatorsandhas an actuator bodywith an extendable actuator rod(see) within a flexible corrugated boot. A similar boot is described in U.S. Pat. No. 8,291,810, which is incorporated herein by reference in its entirety.

As shown in, the actuator bodyhas a lower end portion, and the actuator rodhas an upper end portion. The lower end portionof the actuator bodyof the left side hydraulic actuatoris pivotally connected to the left side rearward support memberwith a pivot axis at a location toward but forward of the rearward lateral beamand rearward of the pivotal connection of the lower end portionA of the left side rearward lifting armto the left side support member, and the upper end portionof the actuator rodof the left side hydraulic actuatoris pivotally connected to a rearward sideC of the left side rearward lifting arm, and when the watercraft liftis in the fully raised position, at a position above the lower end portionA of the left side rearward lifting arm with a pivot axis at a location rearward of the rearward side of the left side rearward lifting arm whereat pivotally connected. Similarly, the lower end portionof the actuator bodyof the right side hydraulic actuatoris pivotally connected to the right side rearward support memberwith a pivot axis at a location toward but forward of the rearward lateral beamand rearward of the pivotal connection of the lower end portionA of the right side rearward lifting armto the right side support member, and the upper end portionof the actuator rodof the right side hydraulic actuatoris pivotally connected to a rearward sideC of the right side rearward lifting arm, and when the watercraft liftis in the fully raised position, at a position above the lower end portionA of the right side rearward lifting arm with a pivot axis at a location rearward of the rearward side of the right side rearward lifting arm whereat pivotally connected. The actuator rodof each of the left and right side hydraulic actuatorsandis selectively extendable from and retractable into the corresponding actuator body.

is a right side view,is rear elevational view andis a rear isometric view of the watercraft liftin the fully raised position.

Selective operation of the left and right side hydraulic actuatorsandin unison rotates the rearward and forward lifting framesandforward and rearward, and as a result, respectively, raises and lowers the left and right side bunksand. The watercraft liftis shown in the fully raised position in, and in a fully lowered position in. When in the fully raised position, preferably, the rearward and forward lifting framesandare rotated forward to a position about 1 to 12 degrees over center to prevent accidental lowering of the left and right side bunksand, and any watercraft thereon, should hydraulic power being applied to left and right side hydraulic actuatorsandbe interrupted. In a preferred embodiment, the pivot through holes in the upper end portionsB,B,B, andB of the lifting arms,,, andused to make the pivotal connections between the lifting arms and the left and right side bunksandare positioned to be adequately over-center, but the lifting arms are approximately vertical for aesthetics, and not to create a lack of over-center concern if the lifting arms have a rearward angle when fully up.

Applying hydraulic pressure to a first port of the left and right side hydraulic actuatorsandin unison to causes extension of their actuator rodsrelative to their actuator bodiesprovides the rotational drive to the rearward and forward lifting framesandto raise the left and right side bunksand, and applying hydraulic pressure to a second port of the left and right side hydraulic actuatorsandin unison to causes retraction of their actuator rods relative to their actuator bodies provides the rotational drive to the rearward and forward lifting frames to lower the left and right side bunksand. Alternatively, if the lifting arms are not over-center, relief of the hydraulic pressure applied to the first port of the left and right side hydraulic actuatorsandallows the bunks to move downward under the weight of lifting frames, bunks and any load on the bunks.

The rearward lifting frameand the forward lifting frameare pivotally connected to the lower framesuch that the left side rearward lifting armand the left side forward lifting armpivot in a first left side plane when raising and lowering the left side bunk, with the first left side plane preferably being defined by the longitudinal center lines of the left side forward and rearward lifting arms, and the right side rearward lifting armand the right side forward lifting armpivot in a first right side plane when raising and lowering the right side bunk, with the first right side plane preferably being defined by the longitudinal center lines of the right side forward and rearward lifting arms.

The pivotal connections of the left side hydraulic actuatorto the left side rearward support memberand the left side rearward lifting armare arranged such that the left side hydraulic actuator rotates about these pivotal connections in a second left side plane when raising and lowering the left side bunk, preferably the second left side plane being coplanar with the first left side plane, and the pivotal connections of the right side hydraulic actuatorto the right side rearward support memberand the right side rearward lifting armare arranged such that the right side hydraulic actuator rotates about these pivotal connections in a second right side plane when raising and lowering the right side bunk, preferably the second right side plane being coplanar with the first right side plane.

As best shown in, the left side rearward support memberincludes a vertically oriented, laterally outward side plateand a vertically oriented, laterally inward side plate, in spaced apart relation, with a connecting floor plateextending between them and rigidly attached to a lower portion of each side plate, to define an upwardly open, left side spacebetween the side plates. The outward side plateis positioned on an outward side of the rearward end portionA of the left side forward beam portionand rigidly attached thereto, and the inward side plateis positioned on an inward side of the rearward end portionA of the left side forward beam portion and rigidly attached thereto. A forwardly located upper support member pivot pinand a more rearwardly located lower support member pivot pinextend between forward end portions of the outward side plateand the inward side plateof the left side support member, which forward end portions comprise the forward end portionB of the left side support member. The upper support member pivot pinis located higher than an upper side of the left side forward beam portionat its rearward end portionA (i.e., at an elevation above the upper side), and the lower support member pivot pinis located lower than a lower side of the left side forward beam portion (i.e., at an elevation below the lower side) and rearward of a rearward end of the rearward end portionA of the left side forward beam portion. In a preferred embodiment, the distance the upper support member pivot pinis located above the upper side of the left side forward beam portionis the same as the distance the pivot axis of the lower end portionA of the left side forward lifting armis located above the upper side of the longitudinal left side beam.

Similarly, the right side support memberincludes a vertically oriented, laterally outward side plateand a vertically oriented, laterally inward side plate, in spaced apart relation, with a connecting floor plateextending between them and rigidly attached to a lower portion of each side plate, to define an upwardly open, right side spacebetween the side plates. The outward side plateis positioned on an outward side of the rearward end portionA of the right side forward beam portionand rigidly attached thereto, and the inward side plateis positioned on an inward side of the rearward end portionA of the right side forward beam portion and rigidly attached thereto. A forwardly located upper support member pivot pinand a more rearwardly located lower support member pivot pinextend between forward end portions of the outward side plateand the inward side plateof the right side support member, which forward end portions comprise the forward end portionB of the right side support member. The upper support member pivot pinis located higher than an upper side of the right side rearward beam portionat its rearward end portionA (i.e., at an elevation above the upper side), and the lower support member pivot pinis located lower than a lower side of the right side rearward beam portion (i.e., at an elevation below the lower side) and rearward of a rearward end of the rearward end portionA of the right side forward beam portion. In a preferred embodiment, the distance the upper support member pivot pinis located above the upper side of the right side rearward beam portionis the same as the distance the pivot axis of the lower end portionA of the right side forward lifting armis located above the upper side of the longitudinal right side beam.

The lower end portionA of the left side rearward lifting armis pivotally connected to the left side support memberby the upper support member pivot pinfor rotation about the upper support member pivot pin, and the lower end portionof the actuator bodyof the left side hydraulic actuatoris pivotally connected to the left side support memberby the lower support member pivot pinfor rotation about the lower support member pivot pin. Similarly, the lower end portionA of the right side rearward lifting armis pivotally connected to the right side support memberby the upper support member pivot pinfor rotation about the upper support member pivot pin, and the lower end portionof the actuator bodyof the right side hydraulic actuatoris pivotally connected to the right side support memberby the lower support member pivot pinfor rotation about the lower support member pivot pin.

The upper end portionof the actuator rodof the left and right side hydraulic actuatorsandare pivotally connected to the rearward sidesC andC of the left and right side rearward lifting armsandusing connection lugsA andA, respectively, thus during rotation of the left and right side rearward lifting arms by the hydraulic actuators to raise the left and right side bunksand, the hydraulic actuators are pushing upward on the lifting arms from under their location of connection to the lifting arms to move the left and right side rearward lifting arms in the first left and right side planes. The connection lugsA andA each support a pivot pinextending between two flanges by which the upper end portionof the actuator rodof the corresponding left and right side hydraulic actuatorsandare pivotally connected to the left and right side rearward lifting armsand. The lugsA andA each have a one-piece extruded construction, which creates a stronger joint since there are no welds that can experience a stress concentration at the edge of the lug. This construction also simplifies the design and reduces cost.

As described above, with these pivotal connections of the left side hydraulic actuatorto the left side support memberat a location between the outward and inward side platesand, the left side hydraulic actuator rotates about the lower support member pivot pinin the second left side plane when raising and lowering the left side bunksubstantially coplanar with the first left side plane, and with these pivotal connections of the right side hydraulic actuatorto the right side support memberat a location between the outward and inward side platesand, the right side hydraulic actuator rotates about the lower support member pivot pinin the second right side plane when raising and lowering the right side bunksubstantially coplanar with the first right side plane. The upper end portionof the actuator rodof each of the left and right side hydraulic actuatorsandis pivotally connected to the corresponding rearward sidesC andC of the left and right side rearward lifting armsandfor rotation about the pivot pin. This coplanar arrangement of the left and right side hydraulic actuatorsand, with the left and right side support membersand, respectively, crates a direct load path, which adds stiffness, strength and durability to the watercraft lift, while reducing the number of bolts required, welding, weight, cost and assembly time. Further, having the upper end portionof the actuator rodof the left and right side hydraulic actuatorsandpivotally connected to the rearward sidesC andC of the left and right side rearward lifting armsandresults in the upward force exerted between the left and right side hydraulic actuators and the left and right side rearward lifting arms having the load applied to the rearward lifting arms in alignment with the first left and right side planes, which reduces the torsion on the rearward lifting arms and the tension stress on the welds, thereby reducing the risk of weld cracking and enables higher hydraulic cylinder loads and higher lifting capacity without increasing the number of hydraulic cylinders used.

One function of the floor platesand(see) is to laterally stiffen the longitudinal beam extending between the rearward and forward lateral beamsandof the lower frame, formed by the combination of the longitudinal left and right side beamsand. The left side spacebetween the outward and inward side platesandis sufficiently wide to receive therein the actuator bodyof the left side hydraulic actuator, with the floor plateserving as a support shelf for the actuator body during assembly of the watercraft lift. The floor plateis positioned such that when the actuator bodyis laid thereon for connection of its lower end portionto left side support member, an aperture in the lower end portion is properly aligned to receive the lower support member pivot pin. Similarly, the right side spacebetween the outward and inward side platesandis sufficiently wide to receive therein the actuator bodyof the right side hydraulic actuator, with the floor plateserving as a support shelf for the actuator body during assembly of the watercraft lift. The floor plateis positioned such that when the actuator bodyis laid thereon for connection of its lower end portionto right side support member, an aperture in the lower end portion is properly aligned to receive the lower support member pivot pin. As best seen in, the distance between the pair of side platesandand the distance between the pair of side platesandis wider at the rearward end (i.e., the pairs of side plates flare outward in the rearward direction) to provide more clearance for the hydraulic actuator bodyand larger diameter corrugated boot, as well as the pinspivotally connecting the upper end portionsof the actuator rodsto the connection lugsA andA, and to provide a wider footprint on rearward connector or saddleson the rearward lateral beamto add strength. The forward end portions of the floor platesandalso dips downward to provide clearance for the hydraulic hoses connected to the hydraulic actuatorsand. The left and right side spacesandbetween the side plates and the floor plates are sufficiently large to receive and nest therein a sufficient portion of the corresponding left and right side hydraulic actuatorsandwhen the watercraft liftis in the fully lowered position, as shown in, without being damaged by contact with the left and right side rearward lifting armsand.

To provide for adjustment of the lateral distance between the left and right side bunksand, so as to better accommodate watercraft of different sizes and hull shapes on the watercraft lift, and also side shift both of the bunks such as to position the watercraft thereon at a desired distance from a dock, the rearward end portionsA andA of the left and right side support membersandare laterally movably and adjustably attached to the rearward lateral beam, and the forward end portionsB andB of the longitudinal left and right side beamsand(and forward end portionsB andB of the left and right forward beam portionsand) are laterally movably and adjustably attached to the forward lateral beam. Each of the rearward end portionsA andA of the left and right side support membersandhas a rearward saddle, through which the rearward lateral beamextends, and each of the forward end portionsB andB of the left and right side forward beam portionsandhas a forward connector or saddlethrough which the forward lateral beamextends, permitting the sliding of the rearward saddlesalong the rearward lateral beam and the sliding of the forward saddlesalong the forward lateral beam during setting up the watercraft liftfor the watercraft to be using the watercraft lift or subsequent lateral positional adjustments of the bunksand. The rearward and forward saddlesandmay be securely clamped to the rearward and forward lateral beamsand, respectively, once the left and right side support membersandand the longitudinal left and right side beamsandare moved to the positions that place the left and right side bunksandat the desired lateral spacing for use of the watercraft liftand retained in that position during subsequent use of the watercraft lift. The saddlesandare used for clamping to the rearward and forward lateral beamsandverses bolted connections since aligning bolt holes or drilling underwater is difficult. The saddlesandhave a downwardly facing open side to assist in assembly, and to enable the lateral side beams to be secure when the saddlesandare loosened for adjusting. The length of the saddlesandis sized to be adequately long to provide stability when the rearward and forward connect membersandare not attached and saddlesandare loosened when bunk width is being adjusted.

By being able to adjust the lateral spacing between the left and right side support membersandand the longitudinal left and right side beamsandto adjust the later spacing between the left and right side bunksand, a number of benefits may be realized. Widening the distance between the left side rearward lifting armand the right side rearward lifting arm, and between the left side forward lifting armand the right side forward lifting arm, also results in the watercraft liftbeing adjustable to minimize the water depth needed to float the watercraft on and off the watercraft lift. The farther the bunks are moved outward to increase the space between them, the lower the keel will be for a typical V-hull watercraft. In this manner, the keel can be lowered until it is just slightly above the rearward lateral beam, hence allowing the watercraft to use the watercraft liftin water shallower than otherwise possible if the lateral spacing between the bunks was not adjustable and fixed at a lateral spacing holding the keel higher above the rearward lateral beam.

Also, watercraft hulls often have running strakes that are longitudinal protruding features or ridges that assist the watercraft in tracking and performance, and other hull protrusions, and if a running strake or other protrusion is located in line with and contacting the bunk, the watercraft will not sit centered or level on the left and right side bunksand. By adjusting the lateral spacing between the longitudinal left and right side beamsandto adjust the lateral spacing between the bunksand, contact of the bunks with strakes and other hull protrusions can be avoided.

In the preferred embodiment, the rearward connector memberand the forward connector member, which extend between the left and right side rearward lifting armsand, and extend between the left and right side forward lifting armsand, respectively, each include a tubeadjustably connected to a left side channel memberA and a right side channel memberB. The rearward connector memberis illustrative of the construction of both the rearward and forward connector membersand, and is best understood by reference to. The use of the tubeand channel membersA andB allows the rearward and forward connector membersandto better handle torsion, which assists in synchronizing movement of the left and right side lifting arms,,, andwhen raising and lowering the bunksand. It further allows the length of the rearward and forward connector membersandto be adjusted to accommodate desired changes in the lateral spacing between the left and right side bunksandto accommodate a particular size and style of watercraft.

The left side channel memberA of the rearward connector memberis a generally U-shaped rearwardly opened channel with an end portion rigidly attached to the left side rearward lifting armand extends laterally inward toward the right side rearward lifting armand terminates in a free end portionA. The right side channel memberB of the rearward connector memberis a generally U-shaped rearwardly opened channel with an end portion rigidly attached to the right side rearward lifting armand extends laterally inward toward the left side rearward lifting arm and terminates in a free end portionB. The distance between the free end portionsA andB is determined by the desired lateral spacing between the left and right side bunksand, with the minimum lateral spacing of the bunks being when the free end portionsA andB touch. To adjust the lateral spacing between the left and right side bunks, the longitudinal left and right side beamsandare laterally moved to a position along the rearward and forward lateral beamsandthat provides the desired lateral spacing between the bunks.

To maintain that lateral spacing during normal use of the watercraft lift, the tubeis positioned within the rearwardly open channels of both the left and right side channel membersA andB, so that it longitudinally extends along at least a portion of both channel members. To secure the tubeto the channel membersA andB, the tubehas a longitudinally extending, rearwardly facing recessA with the inward wall portion of the recess and the forward wall of the tube having a series of laterally spaced apart through holes sized to receive a bolttherethrough. Each of the left and right channel membersA andB has two laterally spaced apart through holes. With the tube and channel members assembled, a plurality of boltsare extended through the through holes of the tube and the corresponding through holes of the left and right channel members and tightened. If subsequently a different lateral spacing between the bunksand, the boltsare loosened for both the rearward and forward connector membersandto allow lateral movement of the longitudinal left and right side beamsandas needed to provide a different desired lateral spacing between the bunks. The width of the recessA is sized to capture the nut of the boltand prevent the nut from rotating and the bolt is tightened or loosened, thus requiring only one wrench to set or change the lateral spacing of the bunks. This tube and channel construction avoids the jamming typically occurring when using telescoping tubes. It should be understood that a similar alternative arrangement for the connector member may use left and right side tubes attached to the left and right side lifting arm, respectively, with a central channel that extends along at least a portion of both of the left and right side tubes and is securable in the manner described above to both to maintain the desired lateral spacing of the bunksand. The recessA may also be configured to accept a decorative trim strip (not shown) to hide the holes of the tubeand the bolts.

An alternative embodiment for adjusting the lateral spacing between the bunksandis shown in. The rearward connector memberis illustrative of the construction of both the rearward and forward connector membersand. In this embodiment, the rearward connector memberand the forward connector member, which extend between the left and right side rearward lifting armsand, and extend between the left and right side forward lifting armsand, respectively, each comprise a left side armA and a right side armB. The left side armA of the rearward connector memberis rigidly attached to the left side rearward lifting armand extends laterally inward toward the right side rearward lifting arm, and the right side armB of the rearward connector memberis rigidly attached to the right side rearward lifting armand extends laterally inward toward the left side rearward lifting arm. The left and right side arms are sufficiently long to overlap at all desired lateral spacings between the bunksand. To secure the left and right side armsA andB together to maintain that lateral spacing of the bunks during normal use of the watercraft lift, each of the left and right side armsA andB has a series of laterally spaced apart through holesC sized to receive bolts (not shown) through corresponding pairs of through hole of the left and right side arms. The preferred embodiment is more desirable since various lengths of connector tubescan be used for a wider range of adjustment without cutting.

The forward saddlesat the ends of the forward end portionsB andB of the left and right side forward beam portionsandeach have a bracket, which projects forwardly beyond and upwardly above the forward lateral beamand support a pivot pinextending between two spaced apart flanges Thus, the lower end portionsA andA of the left and right side forward lifting armsandpivot about a pivot axis forward of the forward lateral beam.

To reduce the movement of the watercraft lift, and hence the water craft supported on the left and right side bunksand, when the watercraft liftis reaching the fully raised position shown inin response to operation of the left and right side hydraulic actuatorsand, the hydraulic actuators have a hydraulic cushion that slows the end-of-stroke movement of the hydraulic actuators as the watercraft lift nears the fully raised position. For watercraft lifts that go over-center in the up position, the boat accelerates in speed as the lift nears the top position, which causes the boat to abruptly stop, which causes the lift to have forward/rearward movement.

There are several means to create a hydraulic cushion, with many designs being complex using springs and valves which adds significant cost, and increases failure risk. In the preferred embodiment of, for example, an as illustrated in, an upper portof the hydraulic actuator is positioned such that the flow restricting piston ringcovers an upper portwith approximately 0.3″ remaining in the stroke. With the upper port covered, the fluid is forced to bypass through the flow restricting piston ring in the piston. This embodiment provides the cushion feature with little to no additional cost. An optional check valve may be used to prevent fluid from flowing from the lower part of the cylinder to the top section, which increases lowering speeds for the first approx. 0.3 inches when the upper port is uncovered.

As previously noted, the lower frameis supported by four legswith the footattached to a lower end of the leg for positioning on the seabed. Since the seabedupon which the watercraft liftis positioned is often not completely level, the left end portionA and the right end portionB of the rearward lateral beam, and the left end portionA and the right end portionB of the forward lateral beam, each has an upright leg socketrigidly attached thereto (as illustrated in), through which one of the legsextends, permitting the leg to slide up and down within the leg socket during setting up the watercraft lift. The leg sockethas a pair of through holesspaced apart to correspond to a selected pair of a plurality of through holesin the leg, with the holes sized to receive boltsto secure the leg within the leg socket with a desired extension of the leg out the lower end of the leg socket. The amount of the extension of each of the four legsout of the four leg socketsis selected to position each of the feeton the seabedwhile maintaining the lower framewith a horizontal orientation.

In addition to the use of bolts to secure each of the legsin the selected position within the leg socket, as shown in, a set screwis located in a threaded aperturelocated in a cornerof the leg socketto provide the maximum number of threads in the aperture in the leg socket corner receiving the set screw, and pushes the leg against the two opposite, perpendicularly arranged faces of the inside of the leg socket (i.e., into the interior corner opposite the aperture defined by these interior faces), which secures the leg within the leg socket in both laterally and longitudinally. This assists in reducing the movement between the leg and the leg socket, to provide greater stability and reduced movement of the watercraft liftwhen in use. This and other features add stiffness to the watercraft liftto reduce movement of the watercraft on the lift when the watercraft lift is operating and also when stationary.

As shown in, the lower through holeof the leg socketis positioned such that if the shaft of a bolt B is inserted into the through holeof the legimmediately below the leg socket, and the leg socket is moved down into contact with the bolt B, the through hole of the leg socket will align with the through hole of the leg immediately above the through hole of the leg into which the shaft of the bolt was inserted. With the through holes of the leg socket and the leg so aligned, the boltshown incan be easily inserted. The same methodology may be used on most any mating telescoping shapes.

As shown in, each of the four leg socketshas a pair of drain holesA which are in fluid communication with an open end of the one of the left end portionA and the right end portionB of the rearward lateral beam, and the left end portionA and the right end portionB of the forward lateral beam, to which it is attached, such that water within the rearward and forward lateral beams drains out through the drain hole and into the interior of the leg socket for discharge. This reduces or eliminates the machining of the large rearward and forward lateral beams to accommodate the drainage of water from within the lateral beams and provides a cleaner look to the watercraft lift.

As shown in, in the preferred embodiment the footis a casting with structural ribbing, and has an upwardly projecting foot connection stud or insert membersized to be received within a lower end portion of the legand be connected thereto with a bolt or pinextending through a through holeA in the foot connection insert member and into the lower one of the through holesof the leg (see). To lower the lower framecloser to the seabedso as to allow use of the watercraft liftin shallower water as shown in, or simply to lower the cost, the legsmay be eliminated and the foot connection insert membersinserted into the lower ends of the leg socketsand be connected thereto with bolts or pinsextending through the lower ones of the through holesof the leg sockets and through holeA in the foot connection insert member, as shown in. The advantage of this approach is shown by a comparison of the use of the leginserted into the leg socketas illustrated inand the use of the foot connection insert memberinserted into the leg socket as illustrated in. The studmay be cross drilled to enable two options for bolt elevation, which can enable geometry for the ‘bolt trick’, which uses a bolt shank temporarily in the first unused exposed hole under the leg sleeve, but also allows for geometry that enables the foot to bolt directly to the leg sleeve with the foot orientated 90 degrees without a leg to save water depth.