Note: Descriptions are shown in the official language in which they were submitted.
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21 27223
TRACTION DEVICE
BACKGROUND OF THE INVENTION
The present invention relates to portable traction devices used to
provide traction on ice, snow, mud, or sand.
Many roads can become difficult to traverse due to snow, ice, mud, and
sand. Vehicles attempting to navigate roads under these conditions can lose
traction and become stuck. When this occurs the vehicle is usually freed by
having any passengers get out and push the vehicle forward or backward until
there is sufficient momentum and traction for the vehicle to move under its
own power once again. If no one is available to push then the driver must seek
assistance from passersby or arrange to have the vehicle towed by another
vehicle both of which can be difficult and time consuming.
Attempts have been made to solve this problem using various devices
such as winches which are expensive and require a fixed point to which a
cable may be attached. Other traction devices are known but they are made of
inflexible materials which makes them difficult to transport and store.
A traction device is required that is easy to transport and use by one
person and which will provide traction on ice, snow, mud, sand, or other
surfaces where it is advantageous to spread out the weight of the automobile
over a greater area to prevent slippage or sinking while at the same time
increasing traction by improving force transfer between the tire and the
supporting surface.
SUMMARY OF THE INVENTION
The invention relates to a traction device designed to provide traction on
ice, snow, mud, sand, or other surfaces where it is advantageous to spread
out the weight of the automobile over a greater area to prevent slippage or
sinking while at the same time increasing traction by improving force transfer
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21 2722 3
between the tire and the supporting surtace.
According to one aspect of the present invention there is provided a traction
device comprising; elongate flexible means, and a plurality of elongate
traction bars
each having two sides that meet at a vertex in an inverted V shaped cross
section
and each side having an edge opposite the vertex forming a contact surface,
the
traction bars being substantially parallel with respect to one another and
connected
to the elongate flexible means adjacent the respective vertices of the
traction bars
at spaced locations along the flexible means such that the elongate flexible
means
may be extended with the contact surfaces of the traction bars placed in
contact
with the ground, and such that the elongate flexible means and traction bars
may
be rolled up for transport or storage.
The traction device is placed between the tire and supporting surface for
biting into both the tire and the surface. Each set of traction bars connected
together by the flexible means forms a gang. The gangs are usually used in
pairs,
where one gang is placed in front of each tire on an automobile for which
improved
traction is required. Each gang is placed such that the first traction bar is
just under
the front of the tire. As the tire begins to turn the first traction bar will
be mounted by
the tire. A vertex of the traction bar presses into the adjacent surface of
the tire
while at the same time the weight of the automobile presses the edges of the
traction bar into the supporting surface. The net result is improved traction.
According to a further aspect of the invention there is provided a traction
device comprising; elongate flexible means, and a plurality of elongate
traction bars
each having two sides that meet at a vertex in an inverted V shaped cross
section
and each side having an edge opposite the vertex forming a contact surface,
the
traction bars being substantially parallel with respect to one another and
connected
to the elongate flexible means at spaced locations along the flexible means
such
that the elongate flexible means may be extended with the contact surfaces of
the
traction bars placed in contact with the ground, and such that the elongate
flexible
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means and traction bars may be rolled up for transport or storage wherein a
plurality of notches are spaced apart along each contact surtace such that the
surface is interrupted.
The notches may have various shapes including, U shape, square shape, V
shape, the V shaped notches may be spaced or side by side to provide a
sawtooth
configuration.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be described in conjunction with the accompanying
drawings in which:
l0 Figure 1 is a top view of one embodiment of the traction device
Figure 2 is a top view of another embodiment of the traction device.
Figure 3 is a side view of the embodiment of Figure 1 showing a cross
section of the traction bars.
Figure 4 illustrates a traction bar with uninterrupted contact surfaces.
Figure 5 illustrates a traction bar with U shaped notches in the contact
surfaces.
Figure 6 illustrates a traction bar with spaced apart V shaped notched edges
in the contact surfaces.
Figure 7 illustrates a traction bar with V shaped notched edges in the contact
surfaces.
Figure 8 illustrates a traction bar with square shaped notched edges in the
contact surfaces.
Figure 9 is a side view illustrating the interaction of the traction bars with
the
tire.
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DETAILED DESCRIPTION 21 2 7 2 2 3
Referring to Figures 1 and 3 the traction device is shown comprising an
elongate flexible means in the form of chains 7, and a plurality of elongate
traction bars 1 each having two sides 2 and 3 that meet at a vertex 4 in an
inverted V shaped cross section. The two sides 2 and 3 have free edges
opposite the vertex 4 extending the length of the traction bar providing
respective contact surfaces 5 and 6. The traction bars 1 are arranged parallel
to one another. The traction bars are connected in sequence to alternate links
in the chains 7, joining said traction bars into a gang. The chain links are
welded to the bar vertices at points 8,9,10 and 11. The chains are spaced in
from the end of the traction bar 12 and 13. The chains provide stability and
prevent twisting of the traction bars when in use and allow the traction bars
to
be rolled up for transport or storage.
For vehicles with standard wheeled tires such as cars, vans, and light
duty trucks two different sized traction bars are recommended. The first
having traction bars of 3/4 x 3/4 x 1 /8 inch angle iron, 12 inches long, the
second having traction bars of 1 x 1 x 1/8 inch angle iron, 12 inches long.
These two sizes are joined by 3116 x 11 /16 x 1 5/8 inch link chains spaced 2
1 /2 inches apart. The spacing is such that it will provide good force
transfer
and traction.
In Figure 2 a second embodiment of this invention is shown wherein a
bolt 14 or other elongate member is placed through every fourth link 15 in
each of the two chains and welded to the link. Each bolt is also welded into
the V at the end of a respective one of the traction bars, thereby fixing the
chains to the ends of the traction bars. For heavy duty use this embodiment is
preferred. The traction bars are 1 1 /4 x 1 1 /4 x 3/16 inch angle iron, 12
inches
long and spaced 3 inches apart. They are joined by 3/16 x 3/16 x 1 1 /8 link
chains. The heavier chain and traction bars makes the traction device
stronger.
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The larger spacing provides better force transfer and therefore traction for
larger tires.
Referring to Figures 4 to 8 the contact surfaces of the traction bars may
be straight 25 or have notches spaced along their lengths to improve the
ability of the traction bars to grip the supporting surface. Exemplary
configurations are: an inverted U notch 26; an inverted V notch 27, with the
notches spaced; an inverted V notch 28, with notches adjacent one another;
and a square notch 29.
Referring to Figure 9 the traction device is usually used in pairs of
gangs, one gang is placed in front of each tire on a vehicle for which
improved
traction is required, usually the drive wheels. Each gang is placed such that
the
first traction bar is just under the front of the tire requiring traction. As
the tire
begins to turn the first traction bar will be mounted by the tire. The vertex
of
the traction bar 4 presses into the tire tread 31 while at the same time the
weight of the automobile presses the contact surfaces 5 and 6 of the traction
bar into the supporting surface. As the tire moves forward the weight of the
vehicle is transferred from one traction bar to the next in sequence.
Because of the spacing of the traction bars the weight of the vehicle is
distributed over a number of traction bars in a manner that provides
continuous force transfer giving super for traction. The traction bars are
spaced
such that the traction device has three or more traction bars in contact with
the tire at any time. The tire is shown riding on the traction bars positioned
to
give the maximum amount of traction. The tire 30 is shown leaving a trailing
traction bar 32, thereby transferring most of the vehicle's weight to the next
following bar 33. The trailing traction bar 32 is held in place during this
process and supplies a limited amount of traction to the tire. Most of the
weight of the vehicle acts on the second traction bar 33 for gripping and
force
transfer. The third traction bar 34 is also in contact with the tire. It is
stablized
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in position by the tire and chains linking it to the second traction bar to
accept
the tire next for gripping and force transfer.
The traction bars being joined together and wider than a tire distribute
the weight of the vehicle over a larger area reducing the localized ground
pressure under an individual tire thereby helping to prevent the tire from
slipping or sinking in. If the tire and traction device do begin to sink,
additional
traction bars are drawn onto the tire by the chains supplying additional
traction
for the vehicle and further distributing the weight of the vehicle helping to
prevent further slipping or sinking.
Since various modifications can be made in my invention as herein
above described, and many apparently widely different embodiments of same
made within the spirit and scope of the claims without departing from such
spirit and scope, it is intended that all matter contained in the accompanying
specification shall be interpreted as illustrative only and not in a limiting
sense.
