Land vehicles – Runner vehicle – With brake
Reexamination Certificate
1999-12-01
2001-10-30
Mai, Lanna (Department: 3619)
Land vehicles
Runner vehicle
With brake
C180S183000, C188S006000
Reexamination Certificate
active
06308966
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates, in general, to snowmobile and other ski vehicle braking and steering systems. More specifically, the invention relates to braking and steering systems that improve control of the vehicle's forward or backward motion even when the conventional braking method, that is, slowing or stopping the drive track for snowmobiles, for example, fails to adequately control the vehicle.
2. Related Art
Snowmobiles, for example, are conventionally slowed or stopped by slowing or stopping the drive track, that is, the endless belt that moves against the snow or ground to power the snowmobile. Because the drive track causes the snowmobile's movement relative to the snow/ground, the drive track is conventionally used to achieve slower movement or to stop movement of the snowmobile. Using this as the sole breaking method, however, can be ineffective and even dangerous in conditions in which the drive track's frictional contact with the snow or ground is not optimum. For example, when the drive track is “clogged” with snow, engagement of the track with the snow on the snowmobile's course is not always sufficient to quickly slow or stop the snowmobile. Or, when the snowmobile is traveling downhill or on icy terrain, the track tends not to grip the terrain adequately. Under these conditions, therefore, the track tends to slip rather than grip the terrain, and the conventional braking system is inadequate. Also, the conventional braking system provides no steering capability, and, in fact, tends to interfere with steering because it tends to lock up the drive tracks and cause skidding.
One attempt at a solution to the braking problem has been posed in the patent literature, as shown in U.S. Pat. No. 5,673,772 (Martin, Oct. 7, 1997). Martin discloses a ski-type runner system which includes a downwardly extendable flap at the rear end of each runner that may be actuated to drag into the snow. Martin teaches that the two flaps are actuated in unison so that balanced braking force is applied to each trailing ski end on both sides of the snowmobile. It is understood, however, that the rearward flap of Martin adversely effects the handling characteristics of the snowmobile during operation.
Another attempt at a solution to this braking problem in shown in U.S. Pat. No. 5,931,481 (Hoffman, Aug. 3, 1999). Hoffman discloses a snowmobile braking system with two (2) blades which are downwardly extendible from each side of the central portion of a ski. Only one of the snowmobile's two skis is equipped with the braking system. It is expected that the single-ski brake of Hoffman will also adversely affect the handling characteristics of the snowmobile during operation.
Still, an effective and safe ski vehicle braking and steering system is needed to improve handling in icy or downhill conditions, for example. Such a braking and steering system is needed that does not depreciate or interfere with handling of the ski vehicle.
SUMMARY OF THE INVENTION
The present invention comprises a braking and steering mechanism that is located near but behind the steering pivot point of a ski runner on a ski vehicle, for example, a snowmobile. In a conventional snowmobile, the steering pivot point is near the middle of the longitudinal axis of the runner, and, hence, the preferred braking and steering mechanism extends from behind the middle of the runner, but not at the rear end as in the Martin reference, to contact the snow or ground to slow or stop the snowmobile movement relative to the snow or ground. The preferred braking and steering mechanism comprises a brake that is a retractable, protruding member that extends down relative to the runner bottom surface near, but behind, the steering pivot point a sufficient distance to frictionally engage the snow/ground significantly more than does the bottom of the runner. The protruding member may take the forms of a prong or spike, a blade or plate, or other single, plural, smooth or toothed member(s) that can make frictional contact with the snow/ground. Preferably, the brake comprises one or more elongated members that extend through and from the bottom of the runner to stab 2-6 inches into the snow/ground. Alternatively, the brake may comprise one or more elongated members that extend alongside the runner to stab 2-6 inches into the snow/ground, provided that the center of gravity of the elongated members and their activating mechanism combined is located near, but behind, the steering pivot point of the ski.
The invented braking and steering system includes an actuator for applying the brake and for retracting the brake. A power screw, hydraulic piston, or other actuator may be used. Controls may be included, preferably at least an on/off system that applies the brake and then retracts the brake, respectively, in a quick and reproducible manner. Optionally, there may be included a control system for partial or incremental application of the brake, for example, for moving the brake varying depths into the snow/ground, or moving the brake to varying angles and positions relative to the snow/ground for varying amounts of frictional engagement or digging action.
Preferably, the invented brake and steering system is installed on both ski runners of the snowmobile. Also, there may be included a control system for differential application of the brake on one side of the snowmobile relative to the other side. This way, assistance in steering the snowmobile may also be obtained. Also, the brake may be controlled so that it is automatically activated when the operator falls off or steps off the vehicle.
REFERENCES:
patent: 1122707 (1914-12-01), Eisen
patent: 3711109 (1973-01-01), Hofbauer
patent: 3726354 (1973-04-01), LaPlante
patent: 3909024 (1975-09-01), Salomon
patent: 4152007 (1979-05-01), Smith
patent: 5853061 (1998-12-01), Yamamoto et al.
patent: 6102413 (2000-08-01), Khennache et al.
Cook Travis A.
Putney Joseph L.
Mai Lanna
Pedersen Barbara S.
Pedersen Ken J.
Restifo Jeff
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