Ships – Vessel raising and docking
Reexamination Certificate
2000-06-01
2001-05-15
Swinehart, Ed (Department: 3617)
Ships
Vessel raising and docking
C405S003000
Reexamination Certificate
active
06230639
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a boat lift having a single drive motor and a plurality of synchronized lifting cables. At least a pair of cables are driven horizontally and longitudinally relative to the boat being lifted or lowered. The boat lift is mounted to multiple pilings or support posts arranged on opposing longitudinal sides of the boat.
BACKGROUND OF THE INVENTION
The boat lifts currently designed for use with medium and larger size vessels exhibit a number of shortcomings. Normally, such lifts feature a respective motor, winder and independently driven cable system mounted to support posts or pilings on each longitudinal side of the boat. As a result, these mechanisms tend to be quite expensive and complicated. Installation is usually time consuming and labor intensive. Utilizing multiple motors is particularly costly and inefficient. Moreover, it is often quite difficult to accurately synchronize the operation of the motors. The respective sides of the lift platform which supports the vessel are apt to be raised or lowered at different rates. The platform is thereby likely to tilt during operation.
At least one known four piling boat lift has eliminated independently operated cables and associated cable beams from respective longitudinal sides of the lift. Instead, that device employs a pair of motors and corresponding pulley assemblies mounted at the front and back ends of the boat lift. This apparatus continues to require a pair of motors, which are quite costly and inefficient. It also exhibits synchronization problems because of the use of multiple independent motors.
Most conventional multiple cable/multiple piling boat lifts experience problems associated with speed reduction and cable wear. The output of each motor must be reduced to provide an appropriate speed and torque for raising and lowering the lift. Today, this almost always necessitates the use of a fairly complex reduction system. Standard cable winders or drums also tend to cause difficulties. Most known winders have a relatively small diameter, which tends to over-stress the cable as it is being wound onto or off of the winder. This can shorten the life of the cables, thereby requiring the lift owner to change cables more often. Such repairs are costly and render the lift inoperable while they are being performed.
SUMMARY OF THE INVENTION
It is therefore an object of this invention to provide a boat lift that utilizes only a single motor to operate multiple lifting cables or wires on both longitudinal sides of the lift.
It is a further object of this invention to provide a single motor boat lift which greatly reduces the expense and complexity normally associated with multiple cable/multiple piling boat lifts.
It is a further object of this invention to provide a boat lift that automatically and accurately synchronizes raising and lowering of the cables or wires on both longitudinal sides of the boat lift so that an improved, stable and level lifting and lowering operation is achieved.
It is a further object of this invention to provide a three or four piling boat lift that employs only a single cable beam on one side of the lift and which therefore eliminates considerable expense and complexity from such lifts.
It is a further object of this invention to provide a single motor, multiple cable boat lift that operates much more reliably and efficiently than known boat lifts.
It is a further object of this invention to provide a boat lift that exhibits simplified drive reduction and reduced cable failure.
It is a further object of this invention to provide a single motor, multiple cable boat lift that may be installed and repaired relatively quickly and conveniently.
It is a further object of this invention to provide a boat lift that may be used effectively with various combinations of single and multiple part lifting cables.
This invention features a single motor, multiple cable boat lift including a lift platform that extends generally between a proximal support structure on one longitudinal side of the boat to be lifted and a distal support structure located on the opposite longitudinal side of the boat. There is a single drive motor mounted to the proximal support structure. As used herein “proximal” is intended to refer to the structure on which the single drive motor and its related transmission components are supported. The motor is selectively driven in opposing first and second directions. The boat accommodating platform includes proximal and distal sides located relatively adjacent to the proximal and distal support structures, respectively. There are first cable means including at least a pair of cables operably connected to the proximal side of the platform for enabling raising and lowering thereof. There are also second cable means including at least a pair of cables operably connected to the distal side of the platform for enabling raising and lowering thereof. At least one cable in each of the first and second cable means is operably mountable to the proximal support structure such that operating the motor causes a portion of the cable to be driven generally horizontally and longitudinally relative to the boat. Cable transmission means operably interconnect each of the cable means with the single motor for retracting the cables when the motor is driven in a first direction to synchronously raise the proximal and distal sides of the platform. The cable transmission means advance the cables when the motor is driven in the second direction to synchronously lower the proximal and distal sides of the platform. As a result, the watercraft mounted on the platform is selectively raised and lowered relative to the water.
In a preferred embodiment, the proximal support structure includes a plurality of spaced apart pilings or support posts disposed on one longitudinal side of the watercraft and the distal support structure includes a second pair of pilings or support posts disposed on the opposite side of the watercraft. The single drive motor and the cable transmission means are preferably mounted to the proximal support structure. That support structure may also specifically comprise a longitudinal cable beam that horizontally interconnects the pilings in the proximal support structure. The motor and cable transmission means may be attached to and generally depend from the longitudinal cable beam between the support post or pilings. Alternatively, the motor and/or cable transmission means may be mounted directly to one or more of the support posts.
Means may be provided for operably mounting at least one cable of each cable means to the proximal support structure such that the cable is movable longitudinally and horizontally relative to the boat. Preferably, both the proximal and distal cable means are mounted in this manner such that each cable in the lift is movable in a generally horizontal and longitudinal fashion. The means for operably mounting the cable means may include directional pulleys that are rotatably mounted in the longitudinal beam.
The proximal cable means may include a pair of single part (e.g. one vertical drop) cables. The distal cable means may include a pair of multiple part (e.g. three part) cables. Each single part cable may engage a pair of directional pulleys in the cable beam, which pulleys direct the single part cable upwardly from the transmission means, longitudinally through the cable beam and vertically downwardly to fasten to the proximal side of the lift platform. More particularly, the lift platform may include a pair of spaced apart cradle beams that are extendable transversely beneath the boat. The lower end of each single part cable may be attached to a proximal end of a respective cradle beam. The lift platform may include a parallel pair of transversely extending cradle beams. Each single part cable is typically attached by a releasable locking apparatus to a respective one of the cable beams adjacent the proximal support structure.
Each multiple part cable may interengage a respective set of multiple directional pulleys. For examp
Carter Daniel S.
Kohlhauff John
McLaughlin Shawn M.
Sargent Charles L.
Noonan William E.
Quality Boat Lifts Inc.
Swinehart Ed
LandOfFree
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