U.S. patent number 3,739,728 [Application Number 05/059,944] was granted by the patent office on 1973-06-19 for portable ski tow and method of operating same.
Invention is credited to John L. Thompson.
United States Patent |
3,739,728 |
Thompson |
June 19, 1973 |
PORTABLE SKI TOW AND METHOD OF OPERATING SAME
Abstract
A portable ski tow winch unit with tow cable serving also as a
control link between a control switch station on the handle end of
the tow cable and controlled actuation means in the winch unit for
operating the winch unit either to wind up cable under power or to
release cable from the winch spool, thereby enabling the winch to
be used to pull itself to the top of a ski hill and when anchored
at the top to be used by skiers to ascent the hill.
Inventors: |
Thompson; John L. (Carbonado,
WA) |
Family
ID: |
22026311 |
Appl.
No.: |
05/059,944 |
Filed: |
July 31, 1970 |
Current U.S.
Class: |
104/173.2;
254/323 |
Current CPC
Class: |
B61B
11/00 (20130101) |
Current International
Class: |
B61B
11/00 (20060101); B61b 011/00 () |
Field of
Search: |
;254/186R,150,168,175.5,175.7,187R ;180/3R,6R ;280/15,16
;242/86.5R,86.5A ;272/56.5SS,32 ;104/173R,173ST |
Foreign Patent Documents
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|
|
|
|
|
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431,598 |
|
Aug 1967 |
|
CH |
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1,121,039 |
|
Apr 1956 |
|
FR |
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555,835 |
|
Apr 1923 |
|
FR |
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Other References
"Portable Ski Lift," Popular Mechanics, February 1969, page
153..
|
Primary Examiner: Oechsle; Anton O.
Assistant Examiner: Kramer; Arnold W.
Claims
What is claimed is:
1. A portable ski tow comprising a sled adapted to be moved on a
snow laden surface, and having a winch and power means for driving
the winch mounted thereon, said winch having a length of cable
wound on the spool thereof, one end of which cable is attached to
the spool of the winch, and the other end of which cable is free of
the winch for unwinding of up to the full length of said cable from
the spool, fairleader means addressing the free end portion of the
cable relatively away from one end of the sled, means on the
opposite end portion of the sled for attaching the sled to a fixed
point on the surface, whereby a substantially fixed relationship
can be maintained between the sled and the point while tension is
applied to the cable, electrically actuatable control means
interconnecting the power means with the winch, to selectively
operate the winch, either in terms of winding the spool or in terms
of releasing the same for pay out of the cable, a weight adapted to
freely slidably engage the snow laden surface, means on the free
end portion of the cable and the weight whereby the cable and
weight can be releasably interconnected to one another, and the
cable can be unwound from the spool by allowing the weight to slide
down an incline of the surface while the spool is released for pay
out of the cable, and manually operable means on the cable adjacent
the free end thereof and electrically interconnected with the
control means along the length of the cable to actuate the control
means from a point adjacent the free end of the cable when the sled
is fixed to a point adjacent the top of the incline.
2. The portable ski tow according to claim 1 wherein the sled
attachment means include an elongated flexible member which is
connected to a fixed point on the sled and extendable to and/or
about the point on the surface.
3. The portable ski tow according to claim 1 wherein the means for
actuating the control means includes an electrical switch element
which is carried on a handle for the skier on the free-end portion
of the cable, and connected in an electrical circuit extending
within the cable to an electrically operated relay disposed on the
sled for the control of the power drive to the winch.
4. The portable ski tow according to claim 1 wherein the weight
takes the form of an inanimate toboggan.
5. The portable ski tow according to claim 4 wherein said
interconnecting means includes means on toboggan for releasably
fastening the cable to the same.
6. A method of setting up and operating a portable ski lift,
comprising attaching to a fixed point adjacent the top of a snow
laden incline or the like, a sled having a power driven winch
mounted thereon which in turn has a length of cable wound on the
spool thereof, one end of which is unwound from the spool and
addressed relatively away from the sled downwardly of the incline;
and while maintaining a substantially fixed relationship between
the sled and the point, alternately repeatedly unwinding and
rewinding the cable from and on the spool, by releasably
interconnecting with one another, the cable and a freely slidable
weight resting on the ground, and allowing the weight to slide down
the incline under the force of gravity, while the spool is released
from the power drive for pay out of the cable, and thereafter
manually operating an actuator on the cable adjacent the one end
thereof, to operate the winch and rewind the cable up the incline
while a skier is in tow thereon.
7. The method according to claim 6 wherein the weight takes the
form of an inanimate toboggan.
8. The method according to claim 6 wherein before the steps
recited, the one end portion of the cable is connected to a point
adjacent the top of the incline, and the winch is operated to wind
the cable on the spool and draw the sled up the incline toward the
point, whereafter the cable is detached from the point and the sled
is reversed to address the cable relatively down the incline for
the earlier recited steps.
Description
DESCRIPTION
This invention relates to a new and improved system, including
method and apparatus, for ski tow applications and the like and has
for its broad object the provision of a practicable and economical
ski lift device that can be used in relatively undeveloped areas so
as to remove some of the effects of pressure of mobs of skiers
crowding in on existing commercial facilities in the more developed
ski areas.
The invention is herein illustratively described by reference to
the presently preferred embodiment thereof; however, it will be
recognized that certain modifications and changes therein with
respect to details may be made without departing from the essential
features involved.
Another object of the invention is to devise a practical method and
apparatus of the described nature emphasizing portability,
versatility and safety. A related purpose of this invention is to
devise ski tow apparatus of a portable nature the manufacture of
which in commercial production will be greatly simplified by
adaptability thereto of existing components now in commercial use
for other, although unrelated, purposes.
A versatile lightweight and relatively inexpensive device of the
described nature which can be afforded by individual families or
small groups of ski enthusiasts is believed to represent an
important contribution to the growing recreational needs of the
people. At the present time commerical ski resorts are overcrowded
and the pressure is increasing. Furthermore, the decreasing number
of remaining areas which lend themselves to development on a
commercial scale without interfering with timber stands, and other
land use requirements, or incuring unduly high development costs,
indicates that there is an end in sight to practical expansion
possibilities following present growth patterns. Accordingly, it is
believed that a portable and versatile individualized ski tow
system will fill an important need inasmuch as it can be used in
many areas which are already available and ready for use without
any development costs and without any interference with other
usages of the lands. Numerous areas exist which will accommodate a
few skiers or perhaps dozens of skiers, but will not justify an
expensive ski lift installation on a commercial scale, nor the cost
of operation thereof requiring attendants and related expenses.
These areas can be found scattered throughout the mountains and
hilly countries of the countryside and can also be found in
municipal areas such as in parklands, golf courses and sometimes
streets that are closed off to traffic during periods of snowfall.
By providing a ski tow device which can easily be transported by
automobile or trailer to these sites, unloaded manually or by
simple handling equipment, then moved under its own power into
operating position, an almost limitless number of ski areas can be
"opened up" to usage without undue effort or expense.
In accordance with this invention, a ski-mounted power-driven
portable winch unit incorporating a selectively drivable and
releasable cable spool is provided with means for selectively
controlling operation of the spool from a remote station.
Preferably, the remote station comprises switch means associated
with one or more handles on the ski tow cable itself and connected
by electrical conductors extending through the cable to the winch
unit where electric control signals provided by the switch means at
the remote control station may be employed to start and stop driven
rotation of the spool, vary the speed at which the spool is being
driven and effect release of the spool when the cable is to be
drawn from the spool downhill for picking up another load of
skiers. In accordance with this invention the device is preferably
intended to pull itself up a ski hill to a suitable operating point
at the top of the hill using the tow cable and winch unit to
perform the function. Once the winch unit draws itself up by its
cable to a suitable operating position at the top of the hill and
is there anchored to a tree or otherwise secured in place, turned
around now so that the spool addresses itself downhill, the cable
may be withdrawn from the spool by appropriate controls releasing
the spool for rotation. When a sufficient length of the tow cable
has been drawn out to reach the bottom of the hill, the unit is
then ready for operation to tow skiers to the top, the process
being repeated any number of times.
Typically, the power unit and control means for the cable comprises
an internal combustion engine and suitable clutching device for
releasably engaging the spool with the power transmission train of
the engine. Such engines, clutches and transmissions are well known
and commercially available. Speed regulating and speed controlling
means of a suitable or conventional nature may also be employed in
the power unit so as to enable the winch to maintain more or less
instant cable take-up speed in each throttle setting of the engine
despite changes of effective spool diameter as accumulated wrap of
the cable increases.
These and other features, objects and advantages of the invention
will become more fully evident from the following description
thereof by reference to the accompanying drawings:
FIG. 1 is a simplified side elevation showing use of the ski tow
device in its normal mode of operation to pull skiers uphill on a
ski slope area.
FIG. 2 is an enlarged side view of the portable winch unit.
FIG. 3 is a front view, and FIG. 4 is a top view of such winch
unit.
FIG. 5 is a simplified schematic diagram of a suitable winch unit
control system.
FIG. 6 is a view illustrating an alternative means (other than a
skier serving his turn of duty) to run the cable downhill for
picking up a load of skiers.
In the illustrated embodiment the power winch unit 10 is shown
mounted on a pair of skis 12, the upturned forward ends 12a of
which are situated at the end of the device addressed by the
fairlead of the spool 14 which carries the tow cable 16. The spool
14 is mounted in a frame with an opening 18 out of which the winch
cable is fed through a fairlead or level wind mechanism 20, the
spool being driven by suitable gearing connected to the
gasoline-powered engine 18, all in a suitable or conventional
manner the details of which may vary and are not essential to an
understanding of the invention. Preferably, the engine unit 18 is
of the gasoline-powered type conventionally employed in power chain
saws and includes a starter cable 20, engine housing 22, fuel tank
24, control handle 26 and associated controls such as throttle,
choke, and ignition switch which are not specifically illustrated.
Provision may also be made for a storage rack 28 at the heel end of
the supporting skis upon which spare fuel tanks 30 may be mounted
along with other equipment such as a tool kit and the like. Also at
this end of the unit there is provided a fastening or anchoring
means 32 to which may be connected a securing strap 34 for
anchoring the unit to the base of a tree, stump or other stationary
object. The fastening 32 may be mounted on one of the skis or a
similar element may be mounted on each ski and the strap ends
connected to the respective elements; alternatively, a similar
fastening 32 may be mounted on a crossbar interconnecting the skis
and constituting part of the platform 28.
As will be appreicated, it is readily possible and desirable in
most applications to provide for changing the speed of cable takeup
at will during towing. This may be done in any of different ways
including shifting gears in the power train between the engine and
the winch spool, changing engine speed, or a combination of both
techniques. In the illustration of FIG. 5 the main tow handle 16a
serves as a remote control station. It is provided with switch
means 16b with multiple contactors, 16b1 and 16b2 in the example,
selectively operable at will by the skier when grasping the tow
handle. Actuation of switch contactor 16b1 to the closed position
forms a circuit through the low-speed control electrical conductor
16c extending lengthwise through the tow cable 16, and the core
cable or ground conductor 16d likewise extending lengthwise through
the tow cable so as to actuate a low-speed control relay 40 which
sets the engine throttle (and/or the drive train from the engine to
the winch spool) for low-speed operation. Alternatively, actuation
of switch element 16b2 to the closed position forms a circuit for
the high-speed control relay 42 through the cable conductor 16e and
the ground conductor 16d so as to set the power unit for high-speed
operation. In either setting a speed clutch 44, normally disengaged
with the engine at idle, is automatically engaged so as to form a
drive connection to the cable spool 14. Such a speed clutch is
conventional in chain saws and the like. Engine governor means may
also be employed, if desired; also, variable-ratio drive mechanism
operable like a governor but referenced to the spool and operable
so as to maintain a substantially constant rate of takeup of the
tow cable 16 during towing operations by compensating for the
increasing effective diameter of the winch spool as cable
accumulates thereon. In any case it will be recognized that control
of winch operation from the remote location of a skier using the
tow is important to his comfort and safety, also to the prudent
operation of the equipment for its protection. Any of different
kinds of operating and speed-changing or regulator control
techniques may be employed to assure such results within the broad
objective thus conceived.
In FIG. 6 there is illustrated a sliding weight 46 to which the
handle end or free end of the tow cable 16 may be fastened at 46a
so as to provide one means of pulling out the cable in a downhill
direction. The bottom of the weight is convex so as to slide easily
over the snow as a tobaggon in an upright position and the top face
of the weight is flat or otherwise formed or adapted to support the
end portion of the cable including the handle 16a and auxiliary
handles 16g, if the latter are mounted at intervals along the
length of the tow cable near such free end to accommodate a number
of skiers at one time. Typically, however, the inanimate weight
will not be used, and instead individual skiers take its place by
taking turns in drawing cable from the winch 10 downhill after each
ascent. This function may be facilitated by providing the skier
with a belt B to the back of which the handle 46 may be fastened
leaving the skier with both hands free during the outhaul
operation.
These and other variations in the practice of the invention will be
evident on the basis of an understanding of the preferred
embodiment disclosed herein.
* * * * *