1. Field of the Invention
This invention relates to lifting devices for watercraft, specifically to improvements in such devices that are employed to lift lighter weight, low profile watercraft, such as personal watercrafts.
2. Description of the Related Art
Users of watercraft have need to lift their watercraft from the water, for example for maintenance or in preparation for land transportation of the watercraft as well as for safe storage. Equally, watercraft users have need to lower their watercraft into the water, for example for launching or simply for flotation at dock. Users have heretofore employed a number of devices for such lifting and lowering.
Exemplary of such devices for small profile watercraft such as Jet SkisĀ®, U.S. Pat. No. 5,143,182, issued to the inventor of the present invention, specifies a lift comprising a single heavy-duty column having a winch mounted on the top thereof for raising and lowering a carriage that is engaged with a track formed on the column. Adjustable arms and bunk rails on the carriage enable adjustment to fit a watercraft. The carriage may be locked in the raised position by a number of means, such as a retaining pin. The winch can be mounted to any side of the column to meet the needs of a particular installation.
Prior art personal watercraft lifts are typically comprised of a large number of welded connections. Such welded connections present risk of metal fatigue and fracture at welded stress points, leading to structural failure. Furthermore, in general there has heretofore been little effort in the art of personal watercraft lift crafting to modularize construction and minimize the number of distinct parts comprising a lift. Prior art design for lifts for personal watercrafts and other low profile watercraft does not lend itself easily to lift construction from a kit by unskilled users.
A further significant limitation of prior art personal watercraft lifts is that the carriage arms of the lift are subject to uneven forces without substantial supporting elements to balance such forces, creating the risk of twisting or even breaking a carriage arm when the lift is under load.
Yet further, while some prior art bunk rails, such as described in U.S. Pat. No. 6,830,410 to Davidson, et al. and U.S. Pat. No. 5,543,837 to Arbaugh, et al. are deformable to adapt to varying hull configurations, the adaptability of such bunk rails to the highly varied hull configurations found in personal watercraft and other light craft is limited.
What is needed is a lift for personal watercraft and other low profile watercraft employing few or no welds, that is adapted for modular assembly permitting distribution of lifts in kit form, that provides support for unbalanced loads on lift arms and that has bunk rails that are adaptable to highly varied hull configurations.
The present invention is a lift for low profile watercraft, substantially comprised of channel-ridge interlocking extruded components, enabling easy construction with minimal or no welded parts. The lift comprises a tower to be mounted to a dock. A winch is mounted on the tower for raising and lowering a carriage assembly engaged with the tower. The carriage assembly is comprised of a pair of forks in the form of a forked v-configuration, the intersection of the two arms retained by a carriage that engages and travels along a channeled track in the tower, transported by a winch-driven cable. Further comprising the carriage assembly and traversing the arms of the fork are two bunk assemblies, each bunk assembly comprising a pivot bar adjustably attached to both carriage forks. Each pivot bar has a ridge along its length, which is configured to engage with channels in bunk clips that are pivotally disposed on the pivot bar, the bunk clips retaining a bunk board, disposed upon which is a bunk for engaging the hull of the watercraft.
The foregoing objects, as well as further objects, advantages, features and characteristics of the present invention, in addition to methods of operation, function of related elements of structure, and the combination of parts and economies of manufacture, will become apparent upon consideration of the following description and claims with reference to the accompanying drawings, all of which form a part of this specification, wherein like reference numerals designate corresponding parts in the various figures, and wherein:
a is an exploded view of a portion of the carriage assembly for an embodiment of the invention, showing the manner of attaching the carriage forks to the carriage;
b is an exploded detail of a portion of the carriage assembly depicted in
a is a perspective view of a bunk assembly of the present invention;
b is an exploded view of the bunk assembly depicted in
a and 5b depict the pivoting action of a bunk assembly of the present invention;
Referring to
As will be clear to those of skill in the art, hand winch 108 is one of many means available for raising and lowering the carriage assembly 112 of the present invention. Among manually operated means are many providing gear advantage and racheting functionality, such as set forth in U.S. Pat. No. 5,211,124 to Reiser. Alternative means include electrically, hydraulically or pneumatically driven winches, such as that of Ledford in U.S. Pat. No. 7,226,041, as well as one or more retractable hydraulically or pneumatically powered pistons, and also cog-driven lift mechanisms and related assemblies well known to those in the art for raising and lowering carriage assemblies for watercraft lifts. The present invention incorporates all such means.
a shows an exploded view of the forks and carriage of carriage assembly 112. Left and right upper forks 202, 204 are connected with bolts to left and right lower forks 206, 208 respectively. The forks all connect to fork lock 210 via a plurality of bolts 212 along the vertical axis and bolts 214 along the horizontal axis (only one of each of bolts 212 and 214 are labeled in
Turning to
Turning now to
As will be evident to those in the art, all metal parts of the boat lift described herein are comprised of either mass produced parts (such as nuts and bolts) available off the shelf, or of extruded materials which are easily manufactured. The parts may be broken down into components that are easily shipped and reassembled, permitting the lift to be sold as a kit for purchaser assembly. As will be further evident to those in the art, the v-configuration of the forks and the engagement of the forks by the bunk pivot bars results in a lift carriage assembly of considerable strength, resisting the tendency of bunk carriage arms generally to twist under uneven loads.
Although the detailed descriptions above contain many specifics, these should not be construed as limiting the scope of the invention but as merely providing illustrations of some of the presently preferred embodiments of this invention. Various other embodiments and ramifications are possible within its scope.
While the invention has been described with a certain degree of particularity, it should be recognized that elements thereof may be altered by persons skilled in the art without departing from the spirit and scope of the invention. Accordingly, the present invention is not intended to be limited to the specific forms set forth herein, but on the contrary, it is intended to cover such alternatives, modifications and equivalents as can be reasonably included within the scope of the invention. The invention is limited only by the following claims and their equivalents.