Note: Descriptions are shown in the official language in which they were submitted.
CA 02332217 2003-03-26
IMPROVED APPARATUS FOR AFFIXING
CLIMBING SKINS TO SKIS
FIELD OF THE INVENTION
This invention relates to a system for securing a climbing skin to the bottom
of a
ski. In particular, the invention relates to a system for securing a climbing
skin to
one end of a resilient tensioning member used to affix the skin to a ski.
BACKGROUND OF THE INVENTION
Climbing skins have been used on skis for many, many years to assist skiers in
ascending slopes. Original climbing skins were made from the skins of animals.
More recently, climbing skins have been made from synthetic fabrics which have
a
nap of stiff, rearwardly angled fibres projecting from their bottom surfaces.
When
the skins are attached to the skis, the skis can be slid in a forward
direction
relatively easily. When the skis are moved in a rearward direction then the
fibres
bite into the snow. By attaching climbing skins to both skis, a skier can
climb up
even a reasonably steep snow slope by sliding one ski forward and then the
other.
Attaching a climbing skin securely to the bottom of a ski in such a way that
the
climbing skin will not be easily dislodged during use and snow will not build
up
between the base of the ski and the climbing skin can be difficult. The
problem of
securely attaching climbing skins to skis is exacerbated by the fact that a
skier may
repeatedly put climbing skins onto skis and take them off during the course of
a
day's skiing.
Early climbing skins simply had straps which were used to attach the climbing
skin
to the ski. Typically straps were provided to stretch the climbing skin
between the
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tip and tail of the ski and additional straps were provided along the edges of
the
climbing skin. The additional straps could be used to tie the climbing skin to
the ski
itself. Such climbing skins tended not to work very well because it is
generally not
possible to tie the skin to a ski tightly enough to prevent snow from building
up
underneath the climbing skin. Furthermore, the numerous straps were time
consuming to attach and keep properly adjusted.
More recently, adhesive climbing skins have been developed. Some adhesive
climbing skins have a hook or the like which hooks over the tip of the ski.
The skin
is simply pressed against the ski base and is detachably held in place by a
tacky
adhesive. Such climbing skins provided acceptable performance when the base of
the ski was dry. However, if the adhesive on the climbing skins becomes
covered
with snow or if the base of the ski becomes wet and has snow adhering to it,
then
the adhesive may not properly hold the climbing skin to the base of the ski.
In such
cases, the climbing skin can become unstuck from the ski especially at the
tail.
Climbing skins which use an adhesive as well as tail and tip straps to hold it
in place
have also become popular. This common tail fixation method is problematic in
that
it is usually necessary to modify the ski to provide a way to attach a strap
to the tail
end of the ski. Some current climbing skin systems have a fixture, such as a
pin
which is screwed into the top surface of the ski near the tail. A strap from
the rear
end of a climbing skin can then be stretched around the tail of the ski and
attached to
the pin. This is not desirable because it requires modification of the ski
itself.
In another common tail fixation method, the skin is riveted to a pair of
sandwiching
metal plates that include an integral hook for engaging the tail end of the
ski.
Because the metal hook is relatively rigid, the strap must be moved to the tip
end of
the ski. Two rectangular metal wire hooks (clips) are typically connected by a
short
(about 4 inches long) elastic, rubbery strip. The skin is fed through a
portion of one
of these separate clips and is looped back to adhere onto itself. The clip on
the other
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end of the elastic strip is hooked over the tip of the ski to hold the skin in
place.
Having the elastic strip located at the tip can be a problem when the skier
accidentally hits the wire loop with the opposite ski thereby knocking the
clip
completely off the tip of the ski. Once the skin is free from the tip of the
ski, it can
drag through the snow and the skin adhesive can become contaminated and
eventually fail.
The straps, or elastic tensioning members, in strap-based skin attachment
systems
are usually made of plastic or rubber. These systems are prone to failure due
to the
harsh conditions they are exposed to. The plastic or rubber tensioning members
can
crack and tear in extreme cold. They are also subject to chemical breakdown
through radiation exposure and oxidation. The metal plate and rivet systems
used for
fastening to the skin fabric can tear out of the comparatively weak skin
fabric and
are extremely difficult to replace in the field. Existing tip and tail systems
have not
directly addressed the long-term reliability issues and repair issues often
encountered
in ski touring.
There is a general need for an attachment system for climbing skins which
ameliorates at least some of the disadvantages of the prior art skin affixing
systems .
SUMMARY OF THE INVENTION
In one of its aspects, the invention is an assembly for attaching an elongated
resilient
tensioning member to a climbing skin. The assembly comprises a generally
rectangular cutout extending inward from one end of the skin, two flat rigid
plates
secured about opposite faces of the end of the skin by means of a plurality of
rivets
extending through apertures in the plates and through the skin. At least one
of the
plates has an opening therethrough. The tensioning member has an elongated
body
portion of substantially uniform thickness. One end portion of the member has
a
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thickness greater than the thickness of the opposite end and than the body
portion,
and the end portion is no longer than the length of the opening. The end
portion is
retained in the opening between the plates and a portion of the tensioning
member
adjacent the end portion extends between the plates along the cutout.
In another aspect of the invention, the portion of the tensioning member that
is
adjacent the end portion is wider than the body portion and the width
corresponds to
the width of the cutout.
In another aspect of the invention, there are at least three rivets on at
least three
sides of the cutout.
In another aspect, the invention is a kit for a climbing skin system
comprising an
elongated climbing skin, a generally rectangular cutout extending inward from
one
end of the skin, two flat rigid plates secured about opposite faces of the end
of the
skin by means of a plurality of rivets extending through apertures in the
plates and
through the skin, with at least one of the plates having an opening
therethrough. The
kit also includes an elongated resilient tensioning member comprising an
elongated
body portion of substantially uniform thickness and two ends, a first of the
ends
having an end portion extending from the first end and having a thickness
greater
than the thickness of a second of the ends and greater than the thickness of
the body
portion. The end portion is no longer than the length of the opening.
In another aspect of the kit invention, a portion of the resilient tensioning
member
adjacent the end portion is wider than the body portion and the width
corresponds to
the width of the cutout.
In a further aspect of the invention, there are at least three rivets on at
Least three
sides of the cutout.
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Other aspects of the invention will be appreciated by reference to the
detailed
description which follows.
BRIEF DESCRIPTION OF THE DRAWINGS
In drawings which illustrate various non-limiting embodiments of the
invention:
Figure 1 is a section through a climbing skin mounting system on the
rear of a ski;
Figure 2 is a top view thereof;
Figure 3 is a bottom view of the tail end of the ski, showing an
attachment assembly according to the invention for attaching the skin to the
strap;
Figure 4 is a cross sectional view (along the line 4-4) of the skin, strap
and attachment assembly according to the invention;
Figure 5 is a schematic, partially cut-away top view of a mounting
system according to an alternative embodiment which has a pair of cords held
in a dual-cord cord lock;
Figure 6 is a side elevation of a clip having a pin projecting from a
location on its rear side;
Figure 7 is a top view of a further alternative embodiment wherein a
cord is held 5 between a pair of spring-loaded cams;
Figure 8 is a section through a further alternative embodiment wherein
a strap is held by a tension lock; and
Figure 9 is a side elevation of a clip according to an alternative
embodiment wherein a strap passes through an upright flange on the clip.
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DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Figures 1 and 2 show a ski IO to which is attached a climbing skin 12.
Elongated
climbing skin 12 has a nap 13 made of rearwardly angled bristles and is
attached to
the base l0A of ski 10 with a suitable removable adhesive 14. An elongated
tensioning strap 16 is affixed to the rear end of skin 12 as discussed in
greater detail
below. Strap 16 is affixed at the tail 10B of ski 10 with a mounting clip 18.
Mounting clip 18 is very generally C-shaped in cross-section and hooks around
the
tail lOB of ski 10. Clip 18 has a low rigid flat portion 15 which extends
underneath
the base l0A of ski I0. Clip 18 is rigid so that it can slide onto tail lOB of
ski 10
but cannot rotate when it is on ski 10. Strap 16 has a number of spaced apart
apertures 17 in its distal portion. A user can apply tension to strap 16, pull
strap 16
around the rear end of clip 18 and then hold strap 16 in place on clip 18 by
hooking
one of apertures 17 around a projecting pin 20 on clip 18.
In the preferred embodiment shown in Figure 1, clip 18 has a raised portion 21
comprising an aperture 22. Strap 16 passes through aperture 22. Thus, clip 18
remains on strap 16 even when skin 12 and strap 16 are removed from the ski
10.
The shape of clip 18 tends to prevent clip 18 from rotating relative to tail
10B of ski
10 under the tension forces exerted on strap 16. Clip 18 may be made from any
suitable material such as steel or a rigid plastic.
Preferably the rear portion 26 of clip 18 has a surface 26A which is disposed
at an
acute angle relative to base portion 15. Thus, when clip 18 is installed and
strap 16
is under tension, the tail end 10B of ski 10 is wedged into the rear end of
clip 18
between surface 26A and lower portion 15 of clip 18. This tends to prevent
clip 18
from sliding sideways in either direction on the tail 10B of ski 10.
Preferably strap I6 and/or skin 12 are slightly resilient so that skin 12 and
strap 16
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remain under tension while in use. Strap 16 may be made from a strip of fabric-
reinforced rubber, or the like. Most preferably, the rearmost end 19 of strap
16 is
broadened. This both prevents the accidental removal of clip 18 from strap 16
and
provides a convenient hand grip for applying tension to strap 16 when
attaching skin
12 to a ski.
In the embodiment shown in Figures 1 and 2, the strap 16 is releasably affixed
to
clip 18 by means of a pin 20 on clip 18 which is received through an aperture
17 in
strap 16. Other suitable means for holding the strap 16 in a tensioned manner
to clip
18 may also be used.
Fox example, the clip may include a jam lever which can be pressed down so as
to
hold the strap in place on the clip by compressing a strap between a cam and a
surface on the clip. Jam levers are known in the art and can be readily
purchased
from various sources. Preferably, the jam lever is installed so that tension
on the
strap tends to tighten the cam, and thereby prevent the strap from loosening
during
use.
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Figures 3 and 4 show a novel attachment means for connecting the resilient
strap 16 to
the climbing skin 12. In the preferred embodiment, two flat rigid plates 60,
fabricated
from steel or other suitable materials, are positioned on the two opposite
sides or faces of
the skin material so as to sandwich the skin material between them. A
generally
rectangular cutout 61 is made in the central portion of the tail end of the
skin to make
room for the strap 16, i.e. it extends inward from the tail end of the skin.
Three holes are
punched through the fabric to make room for the rivets 62. In the preferred
embodiment,
three soft, solid rivets 62 are deformed using a press or hammer to tightly
squeeze the
rigid plates 60 together, thereby securely pinching the skin fabric 12.
Preferably the
rivets are provided on at least three sides of the cutout 61 to maximize the
integrity of the
connection and to minimize fabric tear.
At least one of the two plates 60 includes an opening 63 that is sized to
allow the clip end
of strap 16 to be fed through opening 63 as will be explained below.
The end 64 of the strap that is adapted to be retained in the rivet assembly
includes a
thickened end portion, comprising opposed enlarged (thickened) sides 66, 68.
The end
portion is thicker than the elongated body portion of the strap 16 which has a
substantially uniform thickness, and it is thicker than the opposite end of
the strap. The
thickened end portion is also preferably made no longer than the length of the
opening 63
so as to allow it to be seated within the opening and the cutout in order to
minimize its
profile against the snow or the ski as the case may be.
Preferably the body of the strap 16 and the broadened clip end of the strap
have a
thickness of about 0.080 inches while the thickness through the combined
raised portions
66, 68 of the strap is about 0.180 inches. It is contemplated that the
combined thickness
may range from 0.16 inches and 0.20 inches to achieve the objects of the
invention.
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The portion of the strap that is adjacent the thickened end portion 64 is
broadened to
a width approximately equal to the width of the cutout 61. Once the plates 60
are
assembled with the rivets 62, the strap lb can be fed rearward, i.e. starting
at its
unthickened clip end, through the opening 63 in the plates 60. The strap 16
snaps
into place and is held within the opening in the plates 60 by the dual
opposing raised
portions 66, f>8 of the strap. The thickened end portion is then retained in
opening
63 between the plates b0 and the broadened portion of the strap 16 that is
adjacent
the thickened end portion extends between the plates along the cutout 61. It
will be
appreciated that the strap and skin attachment assembly can be provided as a
kit for
assembly by the skier. Such a kit may comprise, for example, the skin one end
of
which is already sandwiched between the two plates and an elongated strap 16
as
described above including the thickened end portion and preferably the
broadened
adjacent portion matching the width of the cutout.
The preferred embodiment of the strap and skin attachment assembly provides
numerous advantages over the state-of-the-art skin technology. Primarily, the
assembly allows for quick and easy replacement of strap 1G by the skier in the
field.
The skier simply slides a new strap into the plate opening 63. In addition,
the strap
16 can be designed to have a breaking tension lower than the force required to
pull
or tear the plates 60 from the skin 12. The completed assembly is lightweight,
thin,
reliable, and easily field serviceable.
Alternatively, strap 16 could comprise a cord instead of a flat strap or could
comprise a flexible flat member having a cord attached to its end. Such a cord
might
be attached to a climbing skin by passing it around the rear end of the clip
to be held
in place by a cord lock device. Cord lock devices of various types are well
known in
the art. One type has a plug slidably mounted within a housing. The plug is
biased
toward one side of the housing by a spring. The cord passes through apertures
in the
housing and the plug and is jammed between the plug and the housing. A release
button allows a user to displace the plug against the bias force exerted by
the spring
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to release the cord. The cord lock device is preferably of a type which is
designed in
such a manner that tension on the cord tends to tighten the cord lock device.
Figure 5 shows a clip 18C in which a skin 12 is tensioned on a ski 10 with a
dual-
cord cord lock 40. Cords 32 pass between a wedge 42 and inclined walls 43.
Tension on cords 32 tends to pull wedge 43 rearwardly, thereby tightly
gripping
cords 32. The angles of walls 43 relative to the longitudinal center of clip
1$C are
exaggerated in Figure 5. In the Figure 5 embodiment cords 32 pass around
locating
grooves 44 in the rear end of clip 18C . Locating grooves 44 guide cords 32.
When a strap is affixed to a clip 1C by a way of a tab which projects through
a hole
in the strap, it is not necessary that the tab be located in the same position
shown in
Figures 1 and 2. Figure 6 shows a clip 18D according to an alternative
embodiment
wherein a tab 20A projects generally rearwardly from clip 18. This embodiment
is
not preferable because of the enhanced likelihood that strap 16 may become
accidently dislodged from tab 20A in the Figure 6 embodiment during use.
Figure 7 shows a further alternative embodiment wherein a cord 32 which is
attached to the rear end of a climbing skin passes around clip 18E and is held
in
place while tensioned between a pair spring-loaded cams 46. Larger versions of
such
cams are used, for example, to secure ropes on sailing boats.
Figure 8 shows a clip 18F according to a further alternative embodiment
wherein a
strap 16 is held in place by a tension lock assembly 50. Tension locks are
well
known and are commonly used to adjust the lengths of straps on backpacks. In a
tension lock, a strap is doubled hack on itself around a number of surfaces
tending
to resist slippage.
As described above, in preferred embodiments the clip 18 is slidably disposed
on the
strap or cord which is attached to skin 12. This prevents clip 18 from
becoming lost
CA 02332217 2003-03-26
when skin 12 is detached from ski 10. The embodiment of Figures 1 and 2 shows
the strap 16 passing through a pair of slots on either side of a bend in the
upper
portion of clip 18. Clip 18 could be configured in any of various alternative
ways
which also cause clip 18 to be slidably disposed on a strap or cord when the
skin is
detached from a ski. For example, Figure 9 shows a clip 18G wherein a strap or
cord passes through an aperture 55 in a flange 56 which projects upwardly from
a
top surface of clip 18G. A strap or cord could also pass through a loop of
cord or
elastic attached to a clip 18.
While it is not preferred, a strap 16 could also be held to the top of clip 18
by a
section of hook and loop fastener material such VELCRO, having one part on the
clip and another part on the strap. A strap or cord could also be retained on
a clip 18
by a snap fastener, mechanical clamp, or the like. Where a mechanical clamp is
used, a user could pull a strap or cord tight and then secure the strap or
cord in
place by turning a screw or the like.
It will be appreciated that while the embodiments of the invention have been
described in some detail, modifications and alterations thereto may be
practiced
without departing from the scope of the invention.
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