Land vehicles – Wheeled – Coasters
Reexamination Certificate
1998-03-23
2004-02-03
Dickson, Paul N. (Department: 3616)
Land vehicles
Wheeled
Coasters
C280S288100
Reexamination Certificate
active
06685201
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a wheeled, one-person vehicle, and, more particularly, to a road luge.
A snow luge is a one-person, unpowered sled having a light-weight frame and snow runners. The snow luge is designed so that the rider reclines on the frame of the snow luge with the feet extending forwardly. The snow luge is typically used in timed race events run down an icy, trough-type track with banked sides. Snow luges have long been popular in winter sports.
To extend the training period and enjoyment of the snow luge to the summer months and to those areas which get little snow, the road luge was developed. In its most basic form, the road luge replaces the snow runners of the snow luge with wheels, so that the road luge may operate by rolling downhill on pavement. In the most commonly used road luge, a pair of wheels is supported on pivoting axles at each of the front and back ends of an elongated frame, upon which the rider reclines.
Because the road luge does not ride in a fixed track in the manner of a snow luge, there must be a convenient approach for steering the path of the road luge. In the usual approach, neither pair of wheels is directly steerable. Instead, steering is accomplished as the rider leans into the turn and the pairs of wheels naturally pivot to follow the banking of the road luge. The front pair of wheels and their front axle pivot toward the turn, and the rear pair of wheels and their rear axle pivot away from the turn, leading to a tendency for the rear end of the road luge to skid outwardly during the turn. Even in those cases where the front wheels are directly steerable, the rear wheels pivot away from the turn and tend to skid. Inasmuch as steering is accomplished primarily by the shifting of the weight of the rider, errors in steering may often be made which cause the inside or outside wheels to lift off the ground, reducing the contact of the wheels to the pavement and leading to a loss of traction and directional stability in turns. The braking of the conventional road luge is accomplished by the dragging of the rider's feet on the ground. Consequently, the rider feels somewhat insecure when turning the road luge at speed, because of a well-founded perception of lack of stability, a tendency for the rear end to skid outwardly and the road luge to spin out of the turn, and an inability to brake the road luge after it has entered a turn.
The result is that the maximum speed of the road luge on curved courses is limited by the concern of the rider for stability. The popularity of the road luge is also adversely affected by its perceived and actual lack of stability, because many potential users view the road luge as requiring a “daredevil” attitude.
There is a need for an improved design for a road luge which is more stable and steerable than available road luges. The present invention fulfills this need, and further provides related advantages.
SUMMARY OF THE INVENTION
The present invention provides a road luge which is extremely stable in both straight-line and turning conditions at low and high speeds. Steering is accomplished by directly steering the front wheels, accompanied by a natural shifting of the weight of the body of the rider. Direct steering of the wheels and the proper shifting of weight improves the ability to steer the road luge through curved courses, without errors resulting from the overshifting or undershifting of weight as in conventional road luges. There is little if any tendency for the rear end of the road luge to skid outwardly during turns. All of the wheels remain in contact with the ground, both in straight-line and turning movement. Prototypes of the road luge have reached speeds of 80 miles per hour in downhill testing with excellent actual and perceived stability on straight and curved courses.
In accordance with the invention, a road luge used by a reclining rider comprises an elongated frame having a front end and a back end, a back axle supported from the back end of the frame and fixed in orientation relative to the frame, and a single back wheel rotationally mounted on the back axle along a longitudinal centerline of the frame. A front assembly is attached to the frame at a location adjacent to the front end of the frame. The front assembly includes two rotationally mounted and steerable front wheels, with one front wheel on each side of the frame. A body rest is supported on the frame, so that the rider may recline to a substantially horizontal position on the body rest with the rider's feet extending toward the front end of the frame. The body rest is preferably relatively positioned to the back axle such that a center of gravity of the reclining rider is below the back axle. A steering dampener and/or a back-suspension dampener, operable to damp vibrations transmitted through the back wheel, may be provided.
In one preferred embodiment, the front assembly comprises an axle pivot attached to the frame, a front axle support fixed to the axle pivot and pivotable relative to the frame on the axle pivot, and a front axle mounted in the front axle support, with the two front wheels rotationally mounted on the front axle. Preferably, the axle pivot has a pivot axis lying in the vertical plane and oriented at a forwardly inclined axle pivot angle to the horizontal of from about 48 to about 60 degrees. Inclining the pivot angle forwardly improves the stability of the road luge in turns by causing the body of the rider to lean into the turn by the proper amount. The front axle is desirably steerable with foot rests on the front axle support. The back wheel is preferably relatively large in diameter, allowing the back axle to be above the rider's center of gravity and also permitting the use of a bicycle-type brake that is actuatable by the rider.
In another embodiment, the front assembly comprises a front axle hinge having a hinge pivot axis lying in the horizontal plane and oriented parallel to the longitudinal centerline of the frame. A front axle support is hingedly attached to the frame through the front axle hinge, and a front axle is mounted in the front axle support, with the pair of front wheels rotationally and pivotably mounted on the front axle. A linkage causes the wheels to pivot when the rider leans the frame to one side by shifting body weight.
The road luge of the invention substantially increases the stability of this type of vehicle. Both the actual and perceived stability are improved over prior designs, allowing the road luge to be operated at higher speeds. The present design features are preferably applied to an unpowered vehicle, but may also be applied in various combinations to powered vehicles of a similar type. Other features and advantages of the present invention will be apparent from the following more detailed description of the preferred embodiment, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the invention. The scope of the invention is not, however, limited to this preferred embodiment.
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Brendan I. Koerner, “Extreme”, U.S. News & World Report, pp. 52-60 (Jun. 30, 1997).
Dickson Paul N.
Dunn David R.
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