Land vehicles – Ski or skate appliance or attachment
Reexamination Certificate
2001-07-26
2003-07-15
Johnson, Brian L. (Department: 3618)
Land vehicles
Ski or skate appliance or attachment
C280S816000, C280S818000
Reexamination Certificate
active
06592150
ABSTRACT:
BACKGROUND
1. Field of Invention
This invention relates to downhill skiing and other sliding sport activities, specifically to a training device that assists the user with maneuvering and controlling speed.
2. Description of Prior Art
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Skiers and other sliding sport enthusiasts begin their sport without the ability to control their speed, and, or their direction of travel. This lack of control causes embarrassment, anxiety, and sometimes injury. Beginners frequently fall hard on the ground or slide out of control. Beginners often slide near and into people, or obstacles. Most beginning siders first learn to control their speed with a braking wedge maneuver, and later learn to control speed with turning.
Braking Wedge
For speed control, most professionally certified ski instructors in the United States (certified through the Professional Ski Instructors of America) presently teach beginners the braking wedge, formerly called “snow-plow”, before teaching turning. The braking wedge is the main goal of most initial skiing lessons. It requires the beginners assume an awkward position. A braking wedge is not easy to accomplish. The following paragraphs demonstrate why the braking wedge maneuver is unsatisfactory for most beginning skiers:
To perform a braking wedge, the skier arranges their ski tips near one another and positions the tails wide apart, creating a “V” like position with their skis. This pigeon toed and legs spread wide apart position is uncomfortable. In a braking wedge, skiers use a combination of axial forces and surface drag to slow down. The “V” half angle of wedged skis is typically 30° degrees or less. Axial braking forces result from the lateral force times the angle of skis. Thus, only one half of any lateral force is converted into a useful braking force. Insufficient braking encourages people to rail a ski (over-edging it so that it stops slightly laterally). One railed ski may cross over the other ski, or create unwanted travel in the direction that the railed ski is pointing. Adequate surface drag is also difficult to create, especially on icy slopes, steep slopes, or once a beginner has sped up. Drag is created by maximizing the area of the ski that contacts the supporting surface in a laterally displaced manner across the slope. Basically, the skier increases their wedge angle and flattens their skis by supinating (rolling out) their ankles to create more surface drag. This positioning of the body isn't basic for beginners.
Beginners often irritate their knees trying to twist a ski railed while attempting the braking wedge. It is difficult for a tense beginner to lift, or flatten, and correctly reposition a railed ski. To ski straight while braking in a wedge, the skier must maintain their skis in a sufficiently wide wedge stance, with appropriate edge, and create the same friction and drag on each side. Additionally, the wide braking wedge position can result an unexpected split. Many novice skiers abandon the sport after several hours of practice. Other potential skiers never want to try skiing.
The relevant prior art reviewed below concerns training devices that purport to assist skiers with turning and/or controlling speed. Prior art is crowded with braking devices that purport to solve problems with performing the braking wedge, or otherwise controlling speed. Some devices purport to assist with turning as well as braking. Applicable prior art braking devices include devices that help skiers perform a braking wedge, skier-activated braking systems, harness and pole braking systems, and ski-equipped crutches. All these training devices have significant disadvantages. Several prior art snow vehicles are included at the end of the prior art even though none disclose training devices for beginner skiers.
Prior Art Braking Devices
Braking devices that have uses other than providing a moving skier with speed control have been included for completeness because their titles suggest that they are be related. There are two categories of non-applicable ski brake devices. U.S. Pat. No. 3,980,322 is one of a large number of patents residing in prior art listed that relate to devices which prevent a ski from running away from the skier downhill after the binding opens as the skier falls. Such devices have a usefulness which is limited to stopping a run away ski. U.S. Pat. Nos. 2,510,476 (La Salle, 1950) and 4,219,214 (Kostov, 1980) are representative of patents residing in prior art which disclose blade devices mounted to skis and moveable for downward entry into the snow upon which the users skis are operated. Most typically, such devices are employed as brakes during a prior to upward climbing motions to retard a rear slippage of the skis. Such devices have a usefulness which is generally limited to walking or climbing where the skier moves the skis from static starting positions as they climb, not to downhill skiing. If used for slowing skiers, these devices would have the same problems as those listed under the following hand and leg activated devices.
Hand and Leg Activated Braking Devices
Several prior art braking devices provide speed control for skiers with the engagement of probes, flaps or other braking members that dig into the snow. Most devices are attached to or built into the users skis. The brakes are activated by hand held brake layers, ski poles or by rolling the skis onto their edges. U.S. Pat. No. 4,227,708 (Cote, 1980) relates to a plate fixed on the upper surface of a ski. The plate is provided with a notch into which the lower end of a ski pole may be inserted to produce drag against the snow. While the primary purpose of this device is to provide walking traction during cross country skiing, it purports to provide active braking for a cross-country skier moving downhill. It would be difficult for a beginner to pierce the pole tip through the notch while moving. Additionally, the ski pole applies drag only on the outside of each ski while braking. This would tend to spread the tips of the skis, making the skis more difficult to maneuver. U.S. Pat. No. 4,152,007 (Smith, 1979) provides snow flaps that dig down into the surface at the rear ends of skis. They are activated by hydraulic pressure controlled through the grips on the ski poles. Because the flaps in this device are at the rear of the skis, behind the center pivot point of the skis, it interferes with the skiers rotational efforts to pivot their skis left and right about the axis of their leg.
Devices Built Into One'Skis
U.S. Pat. Nos. 4,986,561(Humphrey, 1991); 4,911,461(Humphrey, 1990); 5,145,200 (Humphrey, 1992); and 5,370,415 (Humphrey, 1994) provide ski control systems built into the users skis, where probes are deployed out of the running surface of the skis into the snow surface. They purport to achieve enhanced maneuverability and speed control when downhill skiing. First, the probes are too short to be practical in all conditions, such as soft powder or slush. Furthermore, these devices, like all braking systems that deploy braking members from the users snow skis, cause beginners to develop a non-functional back leaning stance. Skiers quickly establish a preferred for-aft stance when learning to ski. It is best to learn a centered stance, leaning neither forward or backward on the boot cuff, by letting the shins barely touch the forward tongue of the ski boots. As the brakes are engaged on these devices, skiers will lean back to resist to the increased pressure on their leg muscles. Novice skiers can get stuck in this bad habit of leaning back while skiing.
Alteratively, skiers can be taught to lean forward against the cuff of their rigid modern ski boots when engaging the probes. But, this encourages the skier to learn a bad habit of leaning too far forward with their stance. Pressure on the front of the ski can make one's ski tail wash out at the end of a turn, resulting in a skier pointed up hill and about to slide backwards. A skier could avoid leaning fore or aft by using the quadriceps muscles to resist the braking force, but this would b
Johnson Brian L.
Phan Hau
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