Land vehicles – Wheeled – Occupant propelled type
Reexamination Certificate
1999-01-22
2001-03-20
Mai, Lanna (Department: 3619)
Land vehicles
Wheeled
Occupant propelled type
C280S261000, C280S267000, C280S282000, C280S124141, C280S124136
Reexamination Certificate
active
06203043
ABSTRACT:
FIELD OF INVENTION
The present invention relates, generally, to semi-recumbent, four-wheel, human powered cycles.
BACKGROUND OF THE INVENTION
Bicycles of semi-recumbent configuration have potential for greater comfort and speed than conventional bicycles that are ridden with upright posture. However, due to their configuration, semi-recumbent bicycles are more awkward to ride and significant practice is required of experienced riders of conventional bicycles to transition to them. For example, many of the long and short wheel base semi-recumbent bicycles have handlebars for steering mounted on a pivot point beneath the rider. Other semi-recumbent bicycles—mostly those with long wheel bases—have handle bars extending rearwardly from steering shafts mounted in a steering head positioned well forward of the rider. The result of this configuration is that the rider's hands sweep through a large radius arch, in the manner of a tiller on a boat, when steering rather than rotating about a near central pivot point as is typical of a conventional bicycle.
Semi-recumbent, four-wheel cycles are, on the other hand, stable and easy to ride. However, known primarily as utilitarian vehicles, they have been relegated to use in industrial applications for transportation of materials and people in novelty rental fleets near destination resorts and vacation areas. For many reasons they are not satisfactory for bicycle enthusiasts who ride for exercise and sport. For example, a typical four-wheel cycle has a frame constructed of jig-welded heavy steel tubing in a ladder frame configuration. Thus, it is comparatively very heavy and not considered portable by bicycle standards. Due to its weight and size, it cannot be easily carried atop an automobile like a bicycle in a roof top carrier. Outfitted with a canopy for sun or rain protection, relatively small wheels (e.g. 20″ or smaller in diameter) and high gearing, the typical four-wheel cycle is intended to move only at modest speeds.
Furthermore, a typical four wheel cycle has one or both rear wheels driven using a chain drive system with sprockets that requires a long chain run length from the pedaling cranks to the rear wheels. Its ladder frame configuration usually has a fixed seat or an adjustable seat that moves along the ladder frame to accommodate riders of varying leg length. However, it does not compensate for torso length for steering purposes, thus placing the steering wheel or bars in an awkward position for many people.
Additionally, the typical four-wheel cycle does not have a suspension between the frame and wheels to dampen road shock to the rider and allow the tires to maintain constant contact with the road surface for traction and steering control. Instead it relies only on padding in the seat assembly and relatively thick pneumatic tires to dampen shocks to the rider. Without suspension, the framing and wheel sets must be built heavier and stronger to endure the shocks. Since it is not possible to stand up off the seat, as with a conventional bicycle, it can be very uncomfortable to control at high speeds on standard roadways and on off-road terrain. And, the heavy framing and thick pneumatic tires slow the cycle.
SUMMARY OF THE INVENTION
The objective of the invention is an improved semi-recumbent, four-wheel, human powered cycle that is comfortable to ride and may be ridden by riders with minimal training or practice, and that overcomes one or more of the aforementioned problems with prior art four wheel cycles.
In accordance with one aspect of the invention, a semi-recumbent, four-wheel cycle includes a main frame comprised of a single, stiff beam extending from front to back along the axis of the cycle. To make the beam light, it is hollow and possesses a cross-section of a type that provides good rigidity. Thus, it is comparatively portable, and can be transported by an automobile on a roof top carrier. In a preferred embodiment, the beam possesses a hollow U-shaped or box-shaped cross-section. Front and rear wheel assemblies are attached to opposite ends of the beam, each assembly extending in opposite directions. The wheel assemblies are adjusted so that the beam is inclined from front to rear. A seat is mounted on the beam. Adjustment of the seat along a fore-aft direction will also conveniently result in a vertical adjustment of the seat with respect to a steering column and pedals located in fixed positions with respect to the frame. Thus, the cycle is adaptable to allow riders within a large range of body sizes and proportion to ride comfortably and effectively.
Another aspect of the invention includes a semi-recumbent, four-wheel cycle having a fully independent front suspension assembly that depends from the main frame and is steered. In the preferred embodiment, each of two front wheels is attached to an axle integrated with a steering knuckle. Upper and lower A-frame assemblies are pivotally coupled attached to the cycle's main frame and hold between them the steering knuckle. The load of the cycle is supported by a dampened spring extending between the lower arm and the main frame.
Yet another aspect of the invention includes a semi-recumbent, human-powered four-wheel cycle having one or both front wheels driven. Such an arrangement avoids a long chain drive run to a driven rear wheel and offers the advantages of a steering wheel that is also powered by a drive line. In a preferred embodiment, a front wheel is mounted on a drive axle that passes through support bearings in a steering knuckle. A universal joint couples the drive axle to one end of a splined, telescoping drive shaft. The opposite end of the telescoping drive shaft is coupled through a second universal joint to one end of a drive shaft extension. The drive shaft extension is supported by bearings in a fixed position relative to the main frame. Mounted on the drive shaft is a free-spinning hub and chain drive gear cassette cluster. A common cycle chain drive, sprockets, crank set and chain derailluer system thus can be used in an inverted format to power the front wheel.
Finally, in accordance with yet another aspect of the invention, a semi-recumbent, human-powered four-wheel cycle has all four wheels driven.
These and other aspects and advantages of the invention and its preferred embodiments are described below in connection with the appended drawings, in which:
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Hubbard Marc A.
Ilan Ruth
Mai Lanna
Munsch Hardt Kopf & Harr P.C.
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