Marine propulsion – Operator powered drive for propelling means – Rotary cranking arm
Reexamination Certificate
2000-09-27
2001-05-15
Swinehart, Ed (Department: 3617)
Marine propulsion
Operator powered drive for propelling means
Rotary cranking arm
C440S026000
Reexamination Certificate
active
06231408
ABSTRACT:
TECHNICAL FIELD
The invention is directed to a molded plastic modular drive mechanism assembly for a peddle powered aquatic vehicle with a propeller driven by pedal cranks, a toothed pulley, and water-cooled belt drive transmission, T-bar steering handles, a saddle seat and lateral outriggers to enable a passenger to ride the vehicle in a manner similar to a bicycle over a water surface.
BACKGROUND OF THE ART
Recreational aquatic vehicles must be extremely low cost in order to enable them to be commercial viable. In addition, recreational aquatic vehicles must be practically maintenance free and very simple to operate since they are used by a wide variety of people of different ages in often remote locations.
Moulded plastic components are well recognized as being low cost and accurate, however for many mechanical components, the strength and reliability of plastic components is insufficient. In the recreational aquatic vehicle market, the use of plastic components has traditionally been limited to boat hulls, canoes and floats. Metal remains the designer's material of choice when motorized components are used, despite the relatively high cost and weight penalty.
The description of the invention uses a pedal powered aquatic vehicle as an example however, the invention is equally applicable to any recreational aquatic vehicle that does not require external power and is powered either by pedaling action of the passengers. The muscles in the legs on a person are the largest muscle group and the human body is naturally inclined to provide maximum power through the action of the legs.
Submerged propellers used almost exclusively in modern motorized nautical transport. To date however propellers have not been used for recreational non-motorized aquatic vehicles mainly since the associated mechanism is considered too complex, heavy and expensive for commercial viability.
It is an object of the present invention to provide a drive mechanism for a propeller driven pedal powered aquatic vehicle that can be produced inexpensively enough to render it practical for recreational use.
It is a further object of the invention to provide pedal powered drive means for an aquatic vehicle which can be produced using conventional plastic moulding techniques.
It is a further object of the invention to provide an easily maintained mechanism for a pedal powered aquatic vehicle which can be ridden in a manner similar to a bicycle wherein the passenger straddles the vehicle.
It is a further object of the invention to provide a propeller driven mechanism that is not subject to accidental damage during normally expected handling by unskilled operators.
Further objects of the invention will be apparent from review of the disclosure and description of the invention below.
DISCLOSURE OF THE INVENTION
The aquatic vehicle has a buoyant hull with a central longitudinal body with the saddle seat allowing a passenger to be supported in a straddling position. To provide lateral stability two elongate outriggers are disposed laterally from the central hull body with outrigger arms connecting the body to the outriggers. A manual steering mechanism is attached to the hull for steering by the passenger; preferably in the form of a T-bar journaled to the hull connected with cords to a rear mounted rudder.
Pedal powered drive means are mounted to the hull for driving a stem mounted propeller. A pair of pedal cranks are journaled for rotation about a transverse axis. A longitudinal drive shaft with a propeller mounted on the rear end is connected to transmission means mounted on the forward end of the shaft for rotating the shaft in response to rotation of the pedal cranks.
Within the hull of the vehicle is a hollow sump chamber within which the drive means are housed. Preferably, the transmission includes a toothed pulley and toothed drive belt providing gear reduction to a final drive sprocket disc mounted to the longitudinal shaft. The drive belt is twisted between the toothed pulley and the final drive disc in order to provide very inexpensive gear reduction and transfer the direction from rotation about transverse axis to rotation about the longitudinal shaft axis.
The sump is partially flooded with water from a water inlet. Water floods into the sump when the craft with passenger float on the water at a level which submerges the inlet. The drive mechanism is water cooled as water from the sump is splashed over moving parts. Water and any sand or foreign particles are discharged from the sump through a sleeve about the propeller shaft through a drain opening adjacent the propeller.
The propeller includes a central hub and pivotally mounted blades which fold rearwardly to avoid damage when encountering obstacles or when the vehicle is dragged on the beach. The folding of the propeller blades also permits gliding of the vehicle on the water surfaces reducing water resistance.
Therefore, the invention provides significant advantages over prior art aquatic vehicles. The simplicity of the drive system enables the vehicle to be manufactured very cheaply of plastic moulded parts and can be maintained by relatively unskilled persons. The simple drive mechanism is not more complicated than a typical bicycle drive system, for example. The toothed pulley however provides the continuity of thrust required for continuously driving a propeller at high rotational speeds. The simple twisting of the drive belt eliminates the need for complex gear reduction mechanisms to increase the rotational speed and transfer the orientation of rotation from transverse to axial which significantly adds to the cost, can be difficult to maintain and results in friction losses. The simple mechanism and housing can be constructed of relatively inexpensive plastic moulded components. Water-cooling is provided in order to maintain the operating temperature of such plastic components below a temperature where heat damage could occur.
The simple hull may be inexpensively made of plastic in a conventional blow moulding process. The steering mechanism and seat may also be formed of hollow blow moulded plastic shapes. The outriggers provide lateral stability required for a safe operation and permit the passenger to bank on curves providing a ride sensation similar to bicycle or motorcycle riding.
The drive mechanism is also constructed of moulded plastic components for simple assembly and results in an inexpensive lightweight drive compared to conventional metal components. The drive has a housing with two axially spaced apart shaft bearing cradles. The crank shaft is disposed in the cradles, with opposing crank arms and pedal mounts extending perpendicular to the crank shaft axis and outward of the cradles. A drive pulley is mounted on the shaft between the cradles by sliding a pulley central opening along the shaft over at least one pedal mount. Collars disposed on the shaft between the pulley and each cradle retain the assembly in a simple manner.
Further details of the invention and its advantages will be apparent from the detailed description and drawings included below.
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patent: 5651706 (1997-07-01), Kasper
Future Beach Corporation
Kusner Mark
Swinehart Ed
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