Motor vehicles – Ski- or skate-type vehicle for imparting movement to a...
Reexamination Certificate
1996-10-23
2001-02-27
Johnson, Brian L. (Department: 3618)
Motor vehicles
Ski- or skate-type vehicle for imparting movement to a...
C180S184000, C180S190000
Reexamination Certificate
active
06193003
ABSTRACT:
BACKGROUND OF THE INVENTION
FIELD OF THE INVENTION
MORE DETAILED BACKGROUND OF THE INVENTION
A key task in the development of power devices for skiers is to allow the skier maximum degrees of freedom to control the skis while delivering efficient driving thrust.
The shifting of a skier's weight and posture comprise a principal means of controlling skis. It follows that the skier's control task is complicated, and control likely is impaired, to the extent that the operational requirements of a driving device limit the skier's posture and balance on the skis or limit the motion of the skis themselves. Of course, any driving device, by adding a new force into the skier's balancing task, necessarily complicates that task to some degree.
Where the driving thrust is directly applied to the skis themselves, the connection between the skis and the tractor necessarily limits the degrees of freedom of the skis, to the detriment of control. There is, of course, an advantage to driving the skis directly because this can reduce the stress on the skier's legs which otherwise are required to transmit the power to drive the skis uphill. The instant invention avoids direct drive on the skis, thereby leaving greater freedom of movement to the skis and greater potential control of the skis to the skier, but at the price of some additional stress on the skier's legs to transmit the power to the skis.
Where the driving thrust is applied to the body of the skier, that necessarily limits the degrees of freedom in the skier's posture and muscular control. This problem can be better illustrated by reference to some existing devices to power skiers.
For example, in the device of Mehne, U.S. Pat. No. 3,826,323, the driving thrust is delivered through rigid frame against the skier's buttocks and requires that the skier shift some body weight away from the skis onto the driving tractor. These requirements tend to limit or confine the skier's posture on the skis, thus reducing the degrees of freedom available to the skier's body to control the skis.
Mehne's device patented in 1974 shows an apparently rigid frame
7
which delivers thrust from a tracked tractor to the buttocks of the skier when the skier rests a portion, but not all, of his body weight onto frame
7
. Frame
7
, when used to drive the skier, is secured in position on the skier's buttocks by a belt
12
. Frame
7
also is adapted to serve as a backpacking frame to carry the tractor when not in use. Mehne discloses that the proportion of the skier's weight which rests upon the tractor, through frame
7
, is critical to efficient operation of the tractor. This is because the Mehne device alone, without some of the skier's weight, lacked sufficient traction. However, Mehne discloses that if the skier rests too much body weight on the Mehne device it requires an excessively heavy engine to achieve adequate speed. Mehne's device also includes straps
27
and
28
which attach the skier's ankles or boots to the tractor, for the purpose of limiting the separation between the skis and the tractor. Mehne's straps further limit the skier's freedom of movement.
In Allisio's device, as depicted in U.S. Pat. No. 4,519,470, the skier is delivered dual power thrust from both (A) the driven skis and also (B) rigid “ski sticks” (which apparently are the skier's own ski poles) that extend from the tractor between the skier's legs and bear a “seat”
35
which drives against the back of the skier's thighs. Allisio's “ski sticks”
37
are clipped together with a handle
4
, and the tips of the ski sticks are inserted into a plate
39
to form a “rigid connection” to the crawler tractor. At the same time the tractor also drives the skis directly through plates
16
on the rear end of the skis which connect to plates
19
on an ‘articulated connection’
15
to the tractor. It is apparent that adjusting these dual power thrusts on both the skier's thighs and on the skis may be critical to the skier's own balance, hence to control of the skis. It also appears that balancing these dual thrusts on the skier's thighs and the skis must to some extent dictate, and confine, the skier's posture on the skis. The skier's balancing task is further complicated by Allisio's disclosure that “a large part of the skier's weight acts on the self-propelled unit”. Allisio Specification, Column 1, line 25. It appears, therefore, not only that the adjustment of the seat
35
, relative to the tractor's driving connection to the skis, may be critical, but also that the skier's balancing of body weight between the seat
35
and the skier's feet on the skis may be critical.
In the Allisio device, the use of dual thrusts on both the skier'Is thighs and on the skis may be viewed as disadvantageous to the extent that it complicates a skier's balance on the skis by confining the skier's posture and compelling weight-shifting, while simultaneously also limiting the degrees of freedom of the skis themselves by the power thrust through a connection to the ski tails. In addition, the Allisio device requires use of the skier's hands on the handle
4
and deprives the skier of the normal uses of the hands and ski poles for balance and control.
RELATED ART
U.S. PATENT DOCUMENTS.
A variety of tractors and propulsion devices for skis exists.
One functional distinction in the prior art is between those tractors which attach to and directly drive the skis and those which drive the body of the skier rather than the skis.
Some of the many examples of devices which directly drive the skis are Van Voorhees, U.S. Pat. No. 2,625,229, issued Jan. 13, 1953; Gremeret, U.S. Pat. No. 3,568,787, issued Mar. 9, 1971; Thompson, U.S. Pat. No. 3,645,348, issued Feb. 29, 1972; Thompson, U.S. Pat. No. 3,710,881, issued Jan. 16, 1973; McLoed, U.S. Pat. No. 3,809,173, issued May 7, 1974; Husted, U. S. Patent No. 3,853,192, issued Dec. 10, 1974; Husted, U.S. Pat. No. 3,964,560, issued Jun. 22, 1976; and Husted, U.S. Pat. No. 4,035,035, issued Jul. 12, 1977.
A device which drives the body of the skier, rather than the skis, is Mehne, U.S. Pat. No. 3,826,323, issued Jul. 30, 1974. The device of Allisio, U.S. Pat. No. 4,519,470, issued May 28, 1985, drives both the body of the skier and the skis.
A control device for powered skis is disclosed by Shiber, U.S. Pat. No. 3,996,010, issued Jun. 29, 1976.
The foregoing list is intended as illustrative, not exhaustive.
SUMMARY OF THE INVENTION
The invention has several aspects. One aspect is comprised of a rigid pole and belt configured to deliver power to the body of a skier to move the skier uphill, while leaving the skier's hands free to use ski poles and the skier's feet and legs free to balance upon and control the skis. Modifications adapt the invention to power persons riding on snow boards, skates, skate boards, or equivalent devices.
Another aspect of the invention comprises hinged cleats on a crawler-type tractor, adapted to power skiers. The cleats engage the travelling surface when the tractor's forward motion is driven by the rotation of the treads, but the cleats fold back, disengage from the travelling surface and form a sliding surface when the tractor's forward motion is faster than the rotation of the treads. Thus, the cleats automatically engage when the treads are the driving force, as when travelling uphill or on the flat, but disengage, turning the tractor treads into sled runners so that the skier can ski downhill pulling the tractor. The cleats of the invention thus eliminate the necessity to dismount the tractor, fold it into a backpack, and carry it down slope on the skier's back. Of course, the tractor still can be folded into a backpack and carried when desired. A similar mechanism which allows a wheeled tractor's driving wheels to ‘freewheel’ downhill can be employed where a wheeled tractor is used to power a person on skates.
OBJECTIVES, FEATU
Avery Bridget
Johnson Brian L.
Mitchell Silberberg & Knupp LLP
LandOfFree
Lightweight, portable, power-drive unit and accessory... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Lightweight, portable, power-drive unit and accessory..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Lightweight, portable, power-drive unit and accessory... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2611266