# Patent

## Title
Watercraft lift system

## Abstract

A clamping assembly for a watercraft lifting system comprises a load transferring member, a load receiving member, and a clamping member. The load receiving member has an outer tapered surface. The clamping member has opposing flanges extending from a base portion, an outer surface of at least one opposing flange attachable to the load transferring member. An inner surface defined by the flanges and base portion being complementarily tapered to closely nest with the outer tapered surface of the load receiving member.

## Background
RELATED APPLICATIONS
This application U.S. patent application Ser. No. 13/786,080, filed Mar. 5, 2013, is a continuation of U.S. patent application Ser. No. 13/415,791 filed Mar. 8, 2012, now U.S. Pat. No. 8,388,265 which issued on Mar. 5, 2013.
U.S. patent application Ser. No. 13/415,791 is a continuation of U.S. patent application Ser. No. 12/692,520 filed Jan. 22, 2010, now abandoned.
U.S. patent application Ser. No. 12/692,520 claims benefit of U.S. Provisional Patent Application Ser. Nos. 61/146,645 filed Jan. 22, 2009, and 61/146,985 filed Jan. 23, 2009.
The subject matter of all related applications listed above are incorporated herein by reference in its entirety.


TECHNICAL FIELD
This invention relates generally to a watercraft lift system, and more specifically relates to a watercraft lift having load distribution devices arranged on various portions of a lift frame assembly.
BACKGROUND
Conventional watercraft lift systems typically include a kinematically linked frame assembly that generally takes the shape of a parallelogram. By way of example, U.S. Pat. No. 4,895,479 describes a parallelogram-shaped lift having a stationary base coupled to parallel links, which in turn are coupled to a lift platform for supporting a watercraft. As described in U.S. Patent Publication No. 2006/0147268, one or more hydraulic actuators may be coupled to cross members of the lift such that pressurization or depressurization of the actuator moves the lift from a collapsed configuration to a raised configuration, or vice-versa. Other versions of conventional watercraft lift systems include a cable-pulley system for moving the lift between the collapsed and raised configurations.
Conventional watercraft lift systems, whether having a parallelogram-shape or not, have frame members that are typically pin-pin connected. For example, the links are pin-connected to the base and bunk (e.g., upper rail assembly), respectively.
SUMMARY
The present invention generally relates to a watercraft lifting system having one or more devices or assemblies for distributing a weight of the watercraft more efficiently into a frame system that may include a bunk rail assembly, an intermediate frame assembly and a base frame assembly. As discussed above, the conventional pin-pin connections or other hard-point connections used in watercraft lift systems often require structural reinforcements around the connection point. Without such reinforcements, these connection points, which are often in contact with various types of water (salt, brine, river, etc.), become the locus regions for various types of structural failures, such as, but not limited to corrosion and fatigue.
In accordance with an aspect of the invention, a bunk rail assembly for a watercraft lifting system includes a rail having a length sufficient to support a desired type of watercraft; and a load distribution member having a bearing surface shaped to be closely received by a correspondingly shaped surface of the rail, wherein the respective surfaces permit rotation of the rail relative to the load distribution member, wherein the load distribution member is coupled to the rail with a fastener assembly arranged in a through slot formed in a wall of the load distribution member.
In accordance with another aspect of the invention, a watercraft lifting system includes a base frame assembly; an intermediate frame assembly pivotally coupled to the base frame assembly; and a bunk rail assembly pivotally coupled to the intermediate frame assembly, the bunk rail assembly having a rail engaged with a load distribution member that is pin-connected to the intermediate frame assembly, the load distribution member having a periphery surface shaped to be closely received within a correspondingly shaped inner surface of the rail.
In accordance with yet another aspect of the invention, a clamping assembly for a watercraft lifting system includes a load transferring member; a load receiving member having an outer tapered surface; and a clamping member having opposing flanges extending from a base portion, an outer surface of at least one opposing flange attachable to the load transferring member; an inner surface defined by the flanges and base portion being complementarily tapered to closely nest with the outer tapered surface of the load receiving member.’



BRIEF DESCRIPTION OF THE DRAWINGS
Preferred and alternative embodiments of the present invention are described in detail below with reference to the following drawings:
FIG. 1 is a top, right isometric view of a watercraft lifting system in an upright configuration according to an embodiment of the present invention;
FIG. 2 is a side elevational view of the watercraft lifting system of FIG. 1 in a stowed configuration;
FIG. 3 is a perspective, cut-away view of a bunk rail assembly coupled to a load distribution member according to an embodiment of the present invention;
FIG. 4 is an exploded view of the bunk rail assembly of FIG. 3 according to an embodiment of the present invention;
FIG. 5A is a cross-sectional view of the bunk rail assembly of FIG. 4 with the rail rotated with respect to the load distribution member in a first direction according to an embodiment of the present invention;
FIG. 5B is a cross-sectional view of the bunk rail assembly of FIG. 4 with the rail rotated with respect to the load distribution member in a second direction according to an embodiment of the present invention;
FIG. 5C is a perspective view of a load distribution member engaging an accessory component according to an embodiment of the present invention;
FIG. 6 is a perspective view of a contoured clamping system applied to the watercraft lifting system of FIG. 1 according to an embodiment of the present invention;
FIG. 7 is a perspective, exploded view of one of the clamps of FIG. 6;
FIG. 8 is a perspective view of a stanchion-to-base plate assembly for a watercraft lifting system according to an embodiment of the present invention; and
FIG. 9 is a bottom, plan view of the stanchion-to-base plate assembly of FIG. 8 with the base plate removed according to an embodiment of the present invention.



DETAILED DESCRIPTION
As will be described in further detail below, at least one embodiment of the invention includes a watercraft lifting system with a moveable frame assembly and where at least some of the frame members are coupled together using load distribution and/or clamping devices. The moveable frame assembly necessitates some type of pin-connection between frame members. However, these pin-connection joints are also the locations where weight and other forces are transferred through the frame assembly. As a result, the pin-connection joints can be a common maintenance and/or failure region. Thus, the load distribution and/or clamping devices for the watercraft lifting system described herein advantageously provide an improved load transition and consequently reduce local stresses around the pin-connection regions. In turn, the reduced local stresses improves the overall life of the watercraft lifting system, substantially reduces the need to replace an entire frame member in the event of a wear, corrosion or other issue, and reduces the need to structurally reinforce the pin-connection region (e.g., the frame members can be produces a uniform thickness extrusions).
FIGS. 1 and 2 show a watercraft lifting system 100 having a bunk rail assembly 102, an intermediate link or frame assembly 104, a base assembly 106 and a ground support assembly 108. The watercraft lifting system 100 may be used for lifting a variety of watercraft, such as, but not limited to, boats, jet skis, float planes, etc. The various frame members of the watercraft lifting system 100 may take the form of extrusions made from metal, fiber-reinforced composites, or some other material. In the illustrated embodiment, the watercraft lifting assembly 100 takes the form of a parallelogram-type lift in an upright configuration (FIG. 1) and in a stowed configuration (FIG. 2).
The bunk rail assembly 102 includes bunk rails 110 and hull supports 112. The bunk rails 110 will be described in greater detail below. The hull supports 112 may be sized and configured based on the type of watercraft to be lifted and/or transported by the watercraft lifting system 100.
The intermediate frame assembly 104 includes telescoping frame members or links 114 that may be structurally stabilized by upper cross members 116 and lower cross members 118. Similar to the frame members, the cross members 116, 118 may be extrusions made from a desired material. The telescoping links 114 may be coupled together with a detent pin 117 that allows the links 114 to be adjustably lengthened or shortened depending on a water depth, for example. In the illustrated embodiment, an actuator 120, which may take the form of a hydraulic piston-cylinder type actuator, is coupled to the lower cross members 118. Pressurization of the actuator 120 moves the watercraft lifting system 100 from the upright configuration to the stowed configuration, or vice-versa.
The base assembly 106 includes base frame members 122 arranged to support the intermediate frame assembly 104. First clamps 124 are attached to the base frame members 122 to distribute load thereto. In addition, second clamps 126 are arranged to couple the base frame members 122 to the support assembly 108. The first and second clamps, 124, 126, which are described in more detail below, permit load to be transferred through the various frame assemblies without necessitating any local, structural reinforcement of the extruded frame members. Advantageously, this permits the various frame members to be made using lighter and thinner-walled materials.
The support assembly 108 includes the structure for leveling and supporting the watercraft lifting assembly 100 such as when a watercraft vehicle is being deployed into or removed from the water. In the illustrated embodiment, the support assembly 108 includes stanchions 128 adjustably received within sleeves 130 and coupled to base plates 132. Support members 133 engage the sleeves 130 and are configured to also receive the second clamps 126.
FIGS. 3 and 4 show the upper rail assembly 102 having the bunk rail assembly 110 pivotally coupled to the link 114. The bunk rail assembly 110 may include a bunk rail member 134, a load distribution member 136 and an optional end cap 138. The bunk rail 134 may take the form of an extruded or monolithic component having an inner surface that is complementarily shaped and closely receives the load distribution member 136. In addition and as explained in greater detail below, the bunk rail 134 may be coupled to the load distribution member 136 such that the bunk rail 134 may freely rotate over at least a limited range as indicated by arrow 139 when the bunk rail 134 comes into contact with a hull of a watercraft (not shown).
Referring to FIG. 4, a bunk cushion 140 is slideably coupled to the rail 134 and forms a channel therewith in which a reinforcement board 142 may be located. In the illustrated embodiment, the reinforcement board 142 is fixed to the rail 134 with fasteners 144. By way of example, the bunk cushion 140 may take the form of an extruded, elastomeric material while the reinforcement board 142 may take the form of a wood, wood composite, or other durable, yet sufficiently rigid material. The bunk cushion 140 may be grooved or ribbed on its outer surface to help prevent sliding when in contact with the hull of the watercraft. The end cap 138 is configured to engage the rail 134, the bunk cushion 140 and the board 142. In one embodiment, the end cap 138 may be bonded to one or more of the aforementioned components.
The load distribution member 136 operates to distribute load (i.e., weight or other forces) from the bunk rail 134 into the intermediate frame assembly 104 (FIG. 1) by way of links 114. The distribution of load through the load distribution member 136 may advantageously permit the bunk rail 134 to have a constant and uniform cross-sectional shape and therefore not require any structural build-up or padding local to or in vicinity of its connection with the links 114. In turn, the use of the load distribution member reduces the structural complexity and cost of the rail 134. As mentioned above, the load distribution member 136 also provides a bearing surface 145 on which the rail 134 can rotate. The bearing surface 145, as well as the inner surface of the rail 134, may be coated or otherwise treated to resist wear.
In the illustrated embodiment, the load distribution member 136 is pin-connected to the link 114 with a pin 146 received in a link bore 148 and further received in a bore 150 of the load distribution member 136. The pin-connection permits the link 114 to move relative to the rail 134 as the watercraft lift system 100 (FIG. 1) transitions from the upright configuration (FIG. 1) to the stowed configuration (FIG. 2). Slots 152 located on an upper portion of the load distribution member 136 allow for the limited rotation of the rail 134 relative to the load distribution member 136. A fastener assembly that includes a threaded fastener 154 and a bushing 156 may be used to couple the rail 134 to the load distribution member 136. In the illustrated embodiment, the fastener assembly cooperates with the slot 152 to structurally limit the rotation of the rail 134 relative to the load distribution member 136. It is appreciated that the slot and fastener assembly may be replaced with other types of rotational restraint designs, such as structural stops attached to or integrally formed with the rail 134 and arranged to contact the link 114 after the rail has rotated a desired amount.
FIGS. 5A and 5B show a cross-sectional view of the bunk rail assembly 110, which best shows the structural interaction between many of the aforementioned components. Of particular interest, the cross-sectional shapes of the bunk rail 134 and the bunk cushion 140 cooperate to form the channel 157 for the reinforcement member 142. In addition, the cross-sectional shape of the rail 134 permits the bunk cushion 140 to be slideably received and retained.
FIGS. 5A and 5B also show the rotational range of motion permitted by the slot and fastener assembly. Specifically, FIG. 5A shows the rail 134 rotated to a first stopped position where the bushing 156 contacts the load distribution member 136. Likewise, FIG. 5B shows the rail rotated to a second stopped position.
FIG. 5C shows the load distribution member 136 coupled to an accessory component 157. The load distribution member 136 includes one or more flats 159 that form at least a portion of its inner surface. In addition, the load distribution member 136 further includes longitudinal grooves or channels 161. In the illustrated embodiment, the accessory component 157 includes a square or rectangular profile and is sized to be closely received by the flats 159. Fasteners 163 may be used, but may not be necessary, to secure the accessory component 157 to the load distribution member 136. The flats 159, the channels 161 or both may be utilized to receive and secure the accessory component 157. Both features may also advantageously provide a means of anti-rotation, thus preventing the accessory component 157 from rotating relative to the load distribution member 136. Further, the ability to couple the accessory component 157 directly to the load distribution member 136 permits forces from the accessory component 157 to be transferred into the load distribution member 136 while bypassing the bunk rail assembly 102. By way of example and briefly referring back to FIG. 1, the hull supports 112 may be coupled to the load distribution members 136 as discussed above, which in turn means bending loads induced in the hull supports 112 could be reacted by the load distribution members 136 instead of the bunk rail 134 (FIG. 3).
FIG. 6 shows the first and second clamps 124, 126 secured respectively to frame members 122 and 133. In the illustrated embodiment, a load path of the frame assembly may be through the link 114, a load transferring member, into the clamp 124, then into the frame member 122 where the load is beamed over to the clamp 126, which in turn transmits the load into the frame member 133 and finally into the stanchions 128 and base plates (FIG. 1). Some frame members, such as frame member 122, may function as both a load receiving member and a load transferring member. The clamps 124, 126 operate as load distribution devices to eliminate a direct load transfer between frame members.
FIG. 7 shows the clamps 124, 126 having opposing flanges 158 that extend from a base (e.g., upper) portion 160. Each clamp 124, 126 includes an inner, transfer surface 162 defined by the flanges 158 and base portion 160 such that the inner surface 162 is complementarily shaped to closely nest with an outer, contoured, transfer surface of a respective frame member (FIG. 6). In particular, as shown in FIGS. 6 and 7, the inner surface 162 is continuous curved between the opposing flanges 158, as is the complementarily shaped outer transfer surface of the frame member 122. FIG. 7 further illustrates that a thickness of the clamp 124 between the outer attachment surface of the clamp 124 at which the link 114 is attached and the inner transfer surface 162 is greater at one of the opposing flanges than at the other of the opposing flanges. FIG. 6 shows that the clamp 126 similarly defines a continuously curved inner surface and that a thickness of the clamp 126 between the outer attachment surface of the clamp 126 at which the frame member 122 is attached and the inner transfer surface thereof is greater at one of the opposing flanges 158 than at the other of the opposing flanges 158. In addition, the clamps 124, 126 may include a tensioning assembly 164, which may take the form of a bolt, washer and nut assembly. By way of example, the tensioning assembly 164 operates to urge or clamp the opposing flanges 158 toward one another and correspondingly provide a contact pressure between the inner surface 162 of the clamp 126 and the outer contoured surface of the frame member 133. In one embodiment, the inner surface 162 of the clamp 126 includes a parabolically-shaped surface that corresponds to a similarly contoured surface of the respective member. However, the inner surface 162 may have a variety of contours, which generally will have some type of taper or curvature to permit a close fit and sufficient load distribution with the frame member. For example, the sufficient load distribution may include the clamp cooperating with the frame member to distribute load approximately over the length of the clamp. The inner surface 162 may also function as a bearing or wear surface. Thus, the close nesting of the respective clamp and frame member surfaces may advantageously reduce friction between the surfaces when the watercraft lifting system is being utilized.
FIGS. 8 and 9 show the support assembly 108 having the leveling and supporting structure for the watercraft lifting assembly 100. In the illustrated embodiment, the stanchion 128 is fixed to a tubular member 166 extending from the base plate 132 with a fastener assembly 168. Referring to FIG. 9, the stanchion 128 includes a non-circular cross-section, which takes the form of a triangular cross-section in the illustrated embodiment, and an inner surface 170 includes a plurality of protuberances 172 sized to closely receive the circular outer surface 174 of the tubular member 166. The protuberances 172 may take the form of semi-circular bumps according to one embodiment. The protuberances 172 permit a non-circular cross-sectional structural member (e.g., the stanchion 128) to securably receive and join with a substantially circular cross-sectional structural member (e.g., the tubular member 166).
While the preferred embodiment of the invention has been illustrated and described, as noted above, many changes can be made without departing from the spirit and scope of the invention. Accordingly, the scope of the invention is not limited by the disclosure of the preferred embodiment. Instead, the invention should be determined by reference to the claims that follow.

## Claims

1. A clamping assembly for a watercraft lifting system, the clamping assembly comprising:
a load transferring member;
a load receiving member having an outer transfer surface; and
a clamping member having
opposing flanges extending from a base portion,
an outer attachment surface of the clamping member attachable to the load transferring member, and
an inner transfer surface defined by the flanges and base portion, where the inner transfer surface is continuously curved between the opposing flanges; wherein

the clamping member supports the load receiving member such that the outer transfer surface engages a bearing surface portion of the inner transfer surface;
the outer transfer surface and the inner transfer surface are complementary and shaped such that loads are transferred from the load transferring member to the load receiving member substantially evenly at the bearing surface portion of the inner transfer surface; and
a thickness of the clamp member between the outer attachment surface and the inner transfer surface is greater at one of the opposing flanges than at the other of the opposing flanges.

2. The clamping assembly of claim 1 further comprising a tensioning assembly arranged to urge the opposing flanges toward one another and correspondingly increase a contact pressure between the outer transfer surface and the inner transfer surface, where the outer transfer surface and the inner transfer surface are shaped such that, with the clamping member supported on the load receiving member, loads are transferred from the load transferring member to the load receiving member substantially evenly across the outer transfer surface and the inner transfer surface when the tensioning assembly urges the opposing flanges toward one another.

3. The clamping assembly of claim 1 wherein the tensioning assembly includes a threaded fastener that extends through both flanges.

4. The clamping assembly of claim 1 wherein the outer transfer surface of the load receiving member is substantially parabolically-shaped.

5. The clamping assembly of claim 1 wherein a length of the clamping member cooperates with the load receiving member to distribute load from the load transfer member over approximately the length of the clamping member.

6. The clamping assembly of claim 1 wherein at least one opposing flange is attachable to the load transferring member, where the at least one opposing flange attachable to the load transferring member includes the load transferring member pivotally coupled to the flange.

7. The clamping assembly of claim 1 wherein a thickness of the clamp member between the outer attachment surface and the inner transfer surface is greater at the base portion than at the opposing flanges.

8. The clamping assembly of claim 1 wherein the outer transfer surface and inner transfer surface closely nest together such that frictional engagement between the surfaces structurally locks the clamping member onto the load receiving member.

9. A watercraft lifting system comprising:
a base frame assembly comprising
a load transferring member;
a load receiving member having an outer transfer surface, and
a clamping member having opposing flanges extending from a base portion, where
an outer attachment surface of the clamping member is attachable to the load transferring member, and
an inner transfer surface defined by the flanges and base portion, where the inner transfer surface is continuously curved between the opposing flanges, where
the clamping member supports the load receiving member such that the outer transfer surface engages a bearing surface portion of the inner transfer surface; and
the outer transfer surface and the inner transfer surface are complementary and shaped such that loads are transferred from the load transferring member to the load receiving member substantially evenly at the bearing surface portion of the inner transfer surface;


an intermediate frame assembly pivotally coupled to the load transferring member;
a bunk rail assembly pivotally coupled to the intermediate frame assembly; and
a thickness of the clamp member between the outer attachment surface and the inner transfer surface is greater at one of the opposing flanges than at the other of the opposing flanges.

10. The watercraft lifting system of claim 9 further comprising a tensioning assembly arranged to urge the opposing flanges toward one another and correspondingly increase a contact pressure between the outer transfer surface and the inner transfer surface, where the outer transfer surface and the inner transfer surface are shaped such that, with the clamping member supported on the load receiving member, loads are transferred from the load transferring member to the load receiving member substantially evenly across the outer transfer surface and the inner transfer surface when the tensioning assembly urges the opposing flanges toward one another.

11. The watercraft lifting system of claim 9 wherein the tensioning assembly includes a threaded fastener that extends through both flanges.

12. The watercraft lifting system of claim 9 wherein the outer transfer surface of the load receiving member is substantially parabolically-shaped surface.

13. The watercraft lifting system of claim 9 wherein a length of the clamping member cooperates with the load receiving member to distribute load from the load transfer member over approximately the length of the clamping member.

14. The watercraft lifting system of claim 9 wherein the at least one opposing flange is attachable to the load transferring member, where the at least one opposing flange attachable to the load transferring member includes the load transferring member pivotally coupled to the flange.

15. The watercraft lifting system of claim 9 wherein a thickness of the clamp member between the outer attachment surface and the inner transfer surface is greater at the base portion than at the opposing flanges.

16. The watercraft lifting system of claim 9 wherein the outer transfer surface and inner transfer surface closely nest together such that frictional engagement between the surfaces structurally locks the clamping member onto the load receiving member.

17. The clamping assembly of claim 1 wherein a portion of the outer attachment surface is angled relative to the inner transfer surface.

18. The watercraft lifting system of claim 9 wherein a portion of the outer attachment surface is angled relative to the inner transfer surface.