U.S. patent number 3,871,671 [Application Number 05/366,615] was granted by the patent office on 1975-03-18 for radial ski having a profiled running surface.
Invention is credited to Heinz Bildner.
United States Patent |
3,871,671 |
Bildner |
March 18, 1975 |
Radial ski having a profiled running surface
Abstract
A ski having a sole profile which is symmetric to the
longitudinal axis of the ski and defined at both sides by edges of
wear-resistant material and comprising a further edge on each side
projecting laterally over the corresponding first edge on this
side.
Inventors: |
Bildner; Heinz (8221 Seebruck,
DT) |
Family
ID: |
25763399 |
Appl.
No.: |
05/366,615 |
Filed: |
June 4, 1973 |
Foreign Application Priority Data
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Jun 8, 1972 [DT] |
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2227980 |
Feb 27, 1973 [DT] |
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2309782 |
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Current U.S.
Class: |
280/608 |
Current CPC
Class: |
A63C
5/0485 (20130101); A63C 5/04 (20130101) |
Current International
Class: |
A63C
5/00 (20060101); A63C 5/048 (20060101); A63C
5/04 (20060101); A63c 005/04 () |
Field of
Search: |
;280/11.13E,11.13J,11.13V,11.13N,11.13P,11.13Q,11.13L |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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213,292 |
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Jan 1959 |
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OE |
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188,909 |
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Jan 1937 |
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CH |
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Primary Examiner: Goodman; Philip
Attorney, Agent or Firm: Pennie & Edmonds
Claims
I claim:
1. A ski having a profiled running surface which is symmetric to
the longitudinal axis of the ski and defined at both sides by edges
of wear-resistant material, characterized in that at least one
guide strip is provided at each side of the ski forming a further
edge projecting laterally over an edge of wear-resistant material,
in that each said guide strip extends in excess of one-half the
longitudinal length of the ski, and in that each said guide strip
has its lateral projection diminished continuously from the middle
of the ski towards the tip end and tail end thereof.
2. A ski as claimed in claim 1 further characterized in that each
of said guide strips has a vertical extending portion superimposed
over a portion of a lateral end of an edge of wear-resistant
material.
3. A ski as claimed in claim 1, characterised in that the guide
strips are formed by the edges of a metal layer extending
throughout the ski.
4. A ski as claimed in claim 1, characterised in that the guide
strips are strips of uniform width and thickness throughout their
extension and are inserted to different degrees into a groove in
the ski.
5. A ski as claimed in claim 1, characterised in that the guide
strips are angular strips secured to the side walls of the body of
the ski.
6. A ski as claimed in claim 1, characterised in that two
superposed guide strips of symmetric design with respect to the
center plane of the ski are provided, the guide strip arranged
directly above the running surface being narrower than the second
guide strip arranged on said first guide strip.
7. A ski as claimed in claim 1, comprising a carrier provided with
a casing, characterised in that one or several parallel sectional
hollows are included in the carrier.
8. A ski as claimed in claim 1, characterised in that the running
surface profile is of outwardly convex shape.
9. A ski as claimed in claim 8, characterised in that the running
surface is arranged to be slid between steel edges provided with
undercuts.
10. A ski as claimed in claim 1, characterised in that the running
surface is of concavely curved cross sectional shape in the area of
the shovel and of flat cross sectional shape in the middle of the
ski.
Description
THE BACKGROUND OF THE INVENTION
A ski consists of a body or carrier, a running surface or sole and
steel edges at both sides of the running surface. The ski body is
made up of layers or sheets of wood, steel and/or plastic, the
running surface is formed by a plastic coat, and the steel edges
are either bars of rectangular cross section inserted at both sides
of the running surface or metal sectional material with a sharp
outer edge embedded in the plastic.
The running surfaces or soles of known skis have so-called running
grooves to improve the tracking properties of the ski. In most
cases a semi-circular fluting is provided which extends in the
middle of the sole, in other cases, e.g., with jumping skis a
plurality of parallel flutings are provided in the sole. Moreover,
it is known to design the running groove as a broad channel with
rectangular cross section. Finally, ski edges are known which
comprise skids or have an edge profile that tapers outwardly, as
seen in cross section, or have a hollow polished or ground section
similar to skates. It is the purpose of these measures to improve
the ski such that it will better maintain the direction determined
by the skier, in other words hold the track better than is possible
with smooth running surfaces.
An essential factor in considering the usefulness of a ski is the
coordination between the steel edges and the elasticity of the ski.
The steel edges make it possible to bring the ski into engagement
with the ground during a change of direction, i.e., when swinging
or turning so that the skier can dominate the radial drift or
sideslip during a swing, in other words keep it as small as
possible. The elastic properties of the ski should be chosen such
that the steel edge will engage the ground approximately uniformly
over its entire length upon a turn. This engagement of the steel
edges during swinging or turning is necessary especially on trails
or runs, above all on hard runs. With all the known skis only one
steel edge will engage the ground in a turn during which the ski is
slightly tilted inwardly. Any attempt made so far at improving this
engagement was always directed at improving the elasticity of the
ski.
THE OBJECT OF THE INVENTION
It is the object of the invention to provide a ski affording
improved engagement between the edges and the ground not only by
virtue of the elastic properties of the ski but also by the shaping
of the sole of the ski. In this respect optimum properties of the
ski as regards the easiest possible guidance of the ski at the
increased grip are aimed at. This is of essential importance in
particular for slalom skis.
DESCRIPTION OF THE INVENTION
The invention meets this object by the provision of a ski having at
least one guide strip at both sides which forms another edge,
projects laterally beyond the respective edge of the running
surface, and has this lateral projection diminish from the middle
of the ski towards the tip and tail ends. The projection preferably
amounts to zero in the area of the tip and tail ends of the ski, in
other words near the ends there is only one effective steel edge at
each side of the ski, while there are two or more steel edges at
each side in the area of the middle of the ski which enter into
engagement during a turn.
These measures make it possible to enlarge the number of edges in
the central range of the ski which will enter into engagement with
the ground. Furthermore, during a straight run or schuss on a trail
or course only the sole will become effective as a bearing or
supporting surface so that the shaping of the sole according to the
invention makes it possible to decrease the supporting area of the
ski and thus the friction during schussing or straight skiing on
smooth ground at unaltered strength and bearing characteristics in
deep snow. Hereby the speed attainable in comparison with known
skis is higher, under otherwise equal conditions. It is essential
that the edges of the guide strip be separated from the edges of
the base. It was found that such design according to the invention
will impart to the ski a resistance against torsion which does not
surpass the desired extent. A ski according to the invention may
also be furnished with plastic edges instead of steel edges,
provided the plastic edges are of the required strength.
As the multiplication of the steel edges makes it possible to bring
the ski of the invention into better engagement with the ground
during swinging than any known ski, the radial drifting or side
slipping of the ski during a swing can also be kept smaller
without, however, causing the ski tip and tail ends to "dig", i.e.,
to establish too strong an engagement with the ground. Any possible
greater stress on the strength of the ski may be balanced in
accordance with the invention by the provision of hollow spaces
extending side by side along the ski throughout the body. These may
be formed by pipes or tubes or other forms of hollows which may
have condensed or compacted rims, if desired.
Furthermore, it was discovered that a ski according to the
invention can be turned more easily if the running surface is
shaped so as to be slightly convex outwardly, in other words
crowned in the area of the middle of the ski. Preferably this
running surface may be arranged for replacement by being slidable
between the two steel edges of the lowest guide strip.
In another embodiment of the invention the running surface of the
ski has concave shape, as seen in cross section, in the range of
the forward third of the length of the ski, i.e., near the shovel.
This provides for further improvement of the tracking quality of
the radial ski according to the invention.
The invention will be described further, by way of example, with
the aid of the accompanying drawings, in which:
FIG. 1 is a perspective view of a radial ski in accordance with the
invention,
FIG. 1a is a perspective view and a section view of the end of the
ski,
FIGS. 2a, 2b, 3a, 3b, 4a, 4b, and 5a, 5b are cross sectional and
part sectional views, respectively, of skis according to the
invention, each figure marked with an a referring to a section
taken in the area of line I--I in FIG. 1, and each figure marked
with a b referring to a section taken in the area of line II--II in
FIG. 1,
FIG. 6 is an exploded view of a cut through the middle of a ski
according to the invention having three edges at each side and
showing the laminated structure of the ski,
FIGS. 7 to 9 are cross sectional views through the middle of
various embodiments of skis according to the invention,
FIG. 10 represents an embodiment of the invention having a crowned
running surface.
A ski 1 in accordance with the invention is provided in its central
portion with a guide strip 2 having its degree of projection
diminish according to the invention towards the shovel 3 and tail
5, as shown in FIG. 1. In FIG. 2a the guide strip 2 is shown in
section in the area where its projection is the greatest. The
distance by which the guide strip 2 projects in this area is marked
a. FIG. 2b shows a section along line II--II, and it is obvious
that in this area the degree of projection b is much less already
and will become approximately zero at position 4. The same is true
of position 5 at the end of the ski.
In the embodiment shown in FIG. 2 the guide strip 2 is superposed
at both sides over the steel edge 6, the degree of projection 7
diminishing lengthwise of the ski. Both sectional steel edges 6 and
7 are embedded in the body 8 of the ski. The running surface 9
extends between the steel edges 6, 6. As may be seen from FIG. 2b
the running surface has concave shape in the front portion of the
ski.
In the embodiment shown in FIG. 3 the guide strip 2' is in the form
of a continuous metal layer, its projections 7', 7' diminishing
towards the tip and tail ends of the ski. With the embodiment
according to FIG. 4 the guide strips 2" are of uniform width
throughout and are merely inserted to different extents into the
body 8 of the ski. During assembly of the ski resin may be cast
into the remaining spaces 10 and 10' in the recesses for the guide
strips. An alternative solution provides for fixing this guide
strip by screws so that the extent of projection a or b is
adjustable.
FIGS. 5a and 5b show an embodiment with which the guide strip 2"'
may be attached subsequently to the outside of the ski by fastening
means 11.
The embodiment of the invention shown in FIG. 6 comprises a body 8
having three edges at each side. Of these three edges the lowest
one 13, 14 on each side may be tapering. The running surface 9 is
limited by the steel edges 13 and 14. The body 8 is composed of a
plastic casing 15 and of a core 16 likewise made of plastic and
including hollow sections 17 in accordance with the invention. Such
hollow sections may be obtained by the installation of pipes or
tubes or by cavities of any desired cross sectional shape having
edges or rims 17' which consist of the hardened and/or condensed
plastic material of the carrier. In accordance with the invention
two projecting guide strips 19 and 20 are provided, each being
defined by separate steel edges 21 and 22 and 23 and 24,
respectively. FIG. 8 is a diagrammatic sectional view of the
structure shown perspectively in FIG. 6. If the ski is tilted
during a turn such that its edges 14, 22 and 24 will engage the
ground indicated here by the discontinuous line 25, the radial
drift (arrow 26) can be kept much smaller, due to the engagement of
the three steel edges, than in cases where there is only one steel
edge. Moreover, during schussing and on hard runs the ski will move
only on the running surface 9, which means that the frictional
resistance is considerably decreased without affecting the strength
of the ski since the body 8 itself corresponds to the full width of
the ski.
With the embodiment shown in FIG. 7 the guide strip has nearly the
same width as the running surface 9.
The embodiment shown in FIG. 9 comprises a guiding groove 28.
FIG. 10 shows an embodiment of the invention with which an
outwardly convex or crowned running surface 9"' is slidably engaged
between steel edges 31 and 32 provided with undercuts 41 and 40,
respectively. The curvature of the crowned running surface
preferably decreases towards the middle of the running surface. The
curvature as illustrated in FIG. 10 is exaggerated. In a practical
embodiment of the invention the dimension c determined by the
degree of curvature of the running surface is between 0.2 and 1
millimeter, preferably between 0.3 and 0.5 millimeters.
In FIGS. 2a and 5b and 7 to 10 the body 8 is merely shown
diagrammatically in section. All steel edges are marked by narrower
hatching.
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