Recreational sled

A recreational snow sled comprises an elongated molded plastic shell having a longitudinal central rib forming a U-shaped bottom channel of gradually increasing depth toward the rear of the sled. The sled is designed to carry a person seated in a kneeling position straddling the hump formed by the central channel. The rider is restrained at the knees by a strap running across the forward gunwales of the shell. When the sled is sliding downhill, the central channel tends to form a ridge of packed snow enhancing axial stability and maneuverability. The angle of attack may be controlled by leaning backwards so that the front of the sled is tilted up by the knee strap.

BACKGROUND OF THE INVENTION 
The invention relates generally to recreational snow sleds of the molded 
plastic toboggan type. 
Because of their rugged low cost lightweight construction, one-piece vacuum 
formed thermoplastic shell type sleds have became extremely popular in 
recent years. However, the rudimentary runners molded into the bottom of 
conventional plastic shell sleds provide no steering capability and little 
axial stability in deep snow, thus restricting the practical use of the 
sleds to packed snow conditions where the loose snow depth is minimal. 
So-called deep powder snow conditions found in high mountainous areas such 
as the Rocky Mountains in the western United States are generally 
unsuitable for conventional sledding. 
SUMMARY OF THE INVENTION 
The general object of the present invention is to enhance the control and 
axial stability of a one-piece plastic shell sled so that it can be used 
under all snow conditions including deep powder. More specifically, the 
objects of the invention include endowing a one-piece plastic sled with 
true steering capability in deep snow and providing a form of natural 
braking action. A corollary objective is to promote a new form of 
recreational sledding known as downhill powder sled racing. 
These and other objects of the invention are achieved through the 
geometrical design of a one-piece elongated molded thermoplastic shell 
racing sled having a continuously curved bottom with a pronounced central 
longitudinal channel of increasing depth from fore to aft. The sled 
carries one rider seated in a kneeling position straddling the resulting 
longitudinal hump in the floor of the sled. The legs are restrained at the 
knee by means of an adjustable knee strap running transversely across the 
forward gunwales of the sled. The strap and central hump stabilize the 
position of the rider to establish the center of gravity of the sled and 
rider. When the sled is racing downhill, the central channel tends to 
construct a monorail of packed snow enhancing axial stability and enabling 
more precise steering. A natural braking action is effected by leaning 
backwards and lifting the bow of the sled by the knee strap.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The downhill racing sled according to the invention is specifically 
designed to take advantage of deep powder snow conditions. As shown in 
FIGS. 1-3, the sled is comprised of a one-piece elongated molded shell 10, 
preferably of vacuum-molded thermoplastic. (The bow or front is on the 
right as viewed in FIGS. 1 and 2.) The shell 10 presents a generally 
crescent-shaped profile as shown in FIG. 2. The upper outwardly rolled 
molded edge of the shell forms a continuous railing or gunwales 12 
surrounding the sled. The gunwales 12 are raised at the bow to afford 
handholds and to protect against the intrusion of snow. The bottom of the 
sled while generally curved in profile as shown in FIG. 2, exhibis a 
radical hull design with a complex symmetrical geometry. In cross-section 
as shown in FIG. 3, a pair of generally flat parallel runners 14 and 16 
are defined by molded downwardly protruding parallel ribs 18 and 20 and 22 
and 24. The flat areas 26 and 28 between the pairs of ribs act like wide 
skis to support the sled while moving through the snow. The projecting 
ribs 18, 20, 22 and 24 serve to guide the sled in a straight path and 
enhance tracking in packed snow in the conventional manner. Between the 
two runners 14 and 16, a main central channel 30 extends longitudinally 
from the front to the rear of the sled with progressively increasing depth 
as shown in FIGS. 2 and 3. The inside ribs 20 and 22 define the edges of 
the recess 30 and are slightly outwardly flared with gradually increasing 
spacing at both ends of the sled. Inside the sled the molded channel 30 
forms a large longitudinal central rib or keel-like hump 32 running down 
the center of the sled. Because of the increasing depth of the snow 
channel 30 toward the rear of the sled, the hump 32 becomes more 
pronounced toward the rear as shown in phantom in FIG. 2. In the bow, a 
pair of slots 34 are formed in opposite side walls just beneath the 
gunwales to receive the adjustable knee strap 36 (FIG. 4) which extends 
transversely across the gunwales. 
In the embodiment of FIGS. 5 and 6, additional means are included for 
securing the rider in the sled. A center tie-down strap 38 secures the 
bottom of the knee strap 36 to the hump 32 between the rider's thighs. An 
optional cushioned knee stop 40 and foot straps 42 are used in combination 
with the knee strap 36 to maintain the axial position of the rider 
constant relative to the sled. 
In operation, as shown in FIGS. 7 and 8, the sled 10 accommodates a single 
rider seated in a kneeling position straddling the center hump 32. The 
legs are restrained at the knee by the knee strap 40 which can be 
appropriately tensioned and buckled as shown. In the embodiment of FIGS. 5 
and 6, the foot straps form loops which engage the bottom of each foot to 
stop backward sliding of the rider relative to the sled. Forward sliding 
is prevented by the knee stop 40. The object of the various straps and 
stops is to secure the rider to the sled so that the sled serves as a 
controllable surface action as an extension of the body rather than an 
independent vehicle in which the rider is merely a passenger. As the sled 
slides downhill in deep snow, the shallow tapering lead-in portion 30a 
(FIG. 2) tends to pack the snow into the channel 30 and form a continuous 
monorail-like rige of snow under the rider. Leaning backwards slightly 
tends to rotate the sled about a transverse axis pitching the bow of the 
sled upwards so that the deepest part of the channel 30 is brought under 
the center of gravity of the rider thus tending to slow the sled. At the 
same time, the monorail effect provides the sled with greater 
maneuverability. When the rider leans to one side, the snow monorail 
becomes banked tending to turn the sled in an arc. The channel 30 provides 
a kind of "edge-control" analogous to skiing. 
Leaning forward reduces the effect of the channel 30. The shallower depth 
of the channel directly below the rider reduces the sled area in 
frictional contact with the snow. The result is a dramatic increase in the 
sled's speed when schussing downhill. 
Unlike conventional sleds, which are designed with packed snow sledding 
hills in mind, the above-described downhill racing sled displays a new 
principle of sled design which takes advantage of the loose snow depth to 
selectively enhance control while maintaining low cost molded one-piece 
shell design. The large central channel exhibits a pseudo-twin-hull design 
approach not apparent in prior art sleds. 
The channel serves three known functions. First, to a varying degree 
controlled by the rider, the channel serves to pack the snow under the 
rider in a monorail configuration improving axial stability and allowing 
steering of the sled in otherwise loose amorphous snow conditions in which 
conventional runners would be useless. Second, the straddled hump helps 
secure the rider. Third, the channel is a reinforcing rib which increases 
the longitudinal rigidity of the shell thus permitting extremely 
lightweight construction. 
The development of the downhill racing sled described herein with its 
inherently superior maneuverability opens to avid sled enthusiasts 
sledding country formerly accessible only to skiers. Indeed, the radical 
hull design of the downhill sled has the potential to create a distinctly 
new sport. 
The foregoing description of the preferred embodiments is intended to be 
illustrative of one specific configuration according to the general 
principle of the invention. For example, other devices for securing the 
rider on the sled may provide equivalent restraint. These and other 
variations, modifications or additions may be made without departing from 
the spirit and scope of the invention define by the appended claims and 
equivalents thereto.