U.S. patent application number 11/358209 was filed with the patent office on 2006-10-19 for camming device for climbing or use thereof.
Invention is credited to Reese Morley Dawes, Bryson David Ross Robertson, Scott Jacob Thumlert.
Application Number | 20060231708 11/358209 |
Document ID | / |
Family ID | 36889423 |
Filed Date | 2006-10-19 |
United States Patent
Application |
20060231708 |
Kind Code |
A1 |
Robertson; Bryson David Ross ;
et al. |
October 19, 2006 |
Camming device for climbing or use thereof
Abstract
A camming device is provided that has a superior range of
operation, is lighter and has lower internal compressive forces.
The improvement is a result of using a composition having a
co-efficient of friction ranging between 0.35-0.55 affixed to the
contact area, for example, a semi-metallic composition. An improved
method of fall protection is also provided, as is a method of
manufacture.
Inventors: |
Robertson; Bryson David Ross;
(Vancouver, CA) ; Thumlert; Scott Jacob;
(Lethbridge, CA) ; Dawes; Reese Morley;
(Vancouver, CA) |
Correspondence
Address: |
Scott Thumlert
221 Heritage Close
Lethbridge
AB
T1K6R9
CA
|
Family ID: |
36889423 |
Appl. No.: |
11/358209 |
Filed: |
February 22, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60672569 |
Apr 18, 2005 |
|
|
|
Current U.S.
Class: |
248/231.9 ;
248/925 |
Current CPC
Class: |
A63B 29/024 20130101;
A63B 2209/00 20130101 |
Class at
Publication: |
248/231.9 ;
248/925 |
International
Class: |
A47F 5/08 20060101
A47F005/08 |
Claims
1. In a camming device for use as protection in cracks during rock
climbing, comprising at least one pair of lobes, one axle per pair
of lobes, a stem, a loop and a release mechanism, said lobes
comprising: a face having a contact area; an inside edge; an apical
end; and a basal end, to define an inner surface and an outer
surface, wherein the improvement comprises: a composition
comprising at least one metal affixed to said contact area.
2. The camming device of claim 1 wherein said composition is housed
in a recess in said face.
3. The camming device of claim 2 wherein said recess extends
substantially from said apical end to said basal end.
4. The camming device of claim 3 wherein said recess terminates in
a tab at said apical end and a tab at said basal end.
5. The camming device of claim 4 wherein said composition has a
co-efficient of friction in the range of 0.35-0.55.
6. The camming device of claim 5 wherein the co-efficient of
friction is in the range of 0.45-0.55.
7. The camming device of claim 1 wherein the composition comprises
metal selected from the group consisting of aluminum, copper,
bronze and brass.
8. The camming device of claim 4 wherein said composition is
affixed with an adhesive.
9. The camming device of claim 8 wherein said composition is
additionally mechanically affixed.
10. In a camming device for use as protection in cracks during rock
climbing, comprising at least one pair of lobes, one axle per pair
of lobes, a stem, a loop and a release mechanism, said lobes
comprising: a face having a contact area; an inside edge; an apical
end; and a basal end, to define an inner surface and an outer
surface, wherein the improvement comprises: a composition having a
co-efficient of friction ranging between 0.35-0.55 affixed to said
contact area.
11. The camming device of claim 10 wherein said composition is
housed in a recess in said face.
12. The camming device of claim 11 wherein said recess extends
substantially from said apical end to said basal end.
13. The camming device of claim 12 wherein said recess terminates
in a tab at said apical end and a tab at said basal end.
14. The camming device of claim 13 wherein the composition is a
semi-metallic composition.
15. The camming device of claim 13 wherein the composition
comprises a metal selected from the group consisting of aluminum,
brass, bronze and copper.
16. The camming device of claim 15 wherein said composition is
affixed with an adhesive.
17. The camming device of claim 16 wherein said composition is
additionally mechanically affixed.
18. In a rack of camming devices, for use as protection in cracks
during rock climbing, wherein each camming device in the rack
comprises at least one pair of lobes, one axle per pair of lobes, a
stem, a loop and a release mechanism, said lobes comprising: a face
having a contact area; an inside edge; an apical end; and a basal
end, to define an inner surface and an outer surface, wherein the
improvement comprises: five camming devices providing an
operational range of approximately 4.0 inches.
19. The rack of camming devices of claim 18 wherein the improvement
comprises four camming devices providing an operational range of
approximately 2.6 inches.
20. The camming device of claim 1 wherein there are two pairs of
lobes and two axles.
21. The camming device of claim 10 wherein there are two pairs of
lobes and two axles.
22. The camming device of claim 1 wherein there is one pair of
lobes and one axle.
23. The camming device of claim 10 wherein there is one pair of
lobes and one axle.
Description
RELATED APPLICATIONS
[0001] This application claims priority to U.S. provisional patent
application Ser. No. 60/672569, filed 18 Feb., 2005, entitled
Camming Device for Climbing and Use Thereof.
FIELD OF THE INVENTION
[0002] This invention is related to devices to assist rock and
mountain climbers. Specifically, this invention is a climbing cam
that has a superior range as a result of long-lasting high friction
material on the face of the cam and low weight "rope" stem.
BACKGROUND OF THE INVENTION
[0003] Mountain climbing is a sport of limits. Rock climbers are
relentlessly striving to push these limits by enduring personal
physical pain, improving technical climbing abilities and inventing
innovative technical gear. Lowering weight and increasing strength
of climbing gear are the fundamental improvements that are required
to extend the limits of climbable routes. Fall protection is the
key aspect to this. Fall protection is what a climber uses to
secure himself/herself to the rock face while climbing. In the
event of a fall, the "fall protection" will stop the climber
falling to their death. Fall protection requires a delicate balance
between strength requirements and weight conservation.
[0004] A climbing camming device (cam or friend) is one type of
device used as fall protection by mountain climbers. Primarily used
for crack climbing, the cam is inserted into a crack and the safety
rope is fixed to the stem loop. Friction from the rock/aluminum
lobe interface and the outward normal force generated by the unique
cam lobe shape holds the camming device in the crack when loaded by
a fall. Camming devices have revolutionized rock climbing because
climbing routes with parallel crack systems can now be protected.
Also, unlike pitons or other forms of permanent protection, camming
devices do not damage the rock and are easily placed and
removed.
[0005] Camming devices range in size and consist of two to four
aluminum spring-loaded cams (lobes) with a logarithmic spiral
contact shape. These cams are mounted onto a stainless steel axle
and connected to a 3/16'' 302 stainless steel aircraft cable stem.
The climbing rope is fixed to the stem with standard nylon webbing
and when weighted the downward force on the stem forces the cams to
spread and hold into the rock.
[0006] When traveling to and from the climbing site, and while on a
climb, a climber must carry a full range of camming devices in
order to accommodate various crack sizes. For this reason, it is
necessary to consider the weight of the rack of camming devices.
Various approaches have been taken to reduce the weight. Firstly,
aluminum is used as much as possible as it is lighter than steel.
Second, the weight has been further reduced by introducing
apertures into the camming devices. As the number of axles used
also affects the weight of a camming device, weight can be reduced
by using single axle camming devices, rather than the heavier
double axle camming devices. These approaches reduce the weight of
each camming devices, and therefore, the weight of the rack.
[0007] An alternative approach to lightening the weight of the
rack, is to reduce the number of camming devices that needed to be
carried. This can be done by increasing the range a given camming
device. Expansion range is the maximum minus the minimum crevice
size a camming device will tolerate. Double axle camming devices
have more expansion range than single axle camming devices, hence
fewer camming devices need to be carried. However, this gain may be
offset by the increased weight of the double axle camming devices
over that of the single axle camming devices.
[0008] The problem for climbers is how to reduce the weight
required for climbing while remaining within an acceptable safety
margin, based on fit of the camming device in the crack and
strength of the camming device. It is an object of the present
invention to overcome the deficiencies of the prior art.
SUMMARY OF THE INVENTION
[0009] An improved camming device is provided that has a superior
range of operation, is lighter and has lower internal compressive
forces. A camming device is for use as protection in cracks during
rock climbing, and comprises at least one pair of lobes, one axle
per pair of lobes, a stem, a loop and a release mechanism. The
lobes comprise: a face having a contact area; an inside edge; an
apical end; and a basal end, to define an inner surface and an
outer surface. The improvement comprises a semi-metallic
composition comprising at least one metal affixed to the contact
area.
[0010] The composition may comprise metals selected from the group
consisting of aluminum, brass, bronze and copper. The composition
may be semi-metallic. By semi-metallic it is meant that a portion,
ranging from a trace to a substantial amount of the composition is
metal, but that it is only one component of the composition, which
may comprise one or more other components.
[0011] In another aspect of the invention the composition is housed
in a recess in the face.
[0012] In another aspect of the invention the recess extends
substantially from the apical end to the basal end.
[0013] In another aspect of the invention the recess terminates in
a tab at the apical end and a tab at the basal end.
[0014] In another aspect of the invention the composition has a
co-efficient of friction in the range of 0.35-0.55.
[0015] In another aspect of the invention the co-efficient of
friction is in the range of 0.45-0.55.
[0016] In another aspect of the invention the co-efficient of
friction is about 0.46.
[0017] In another aspect of the invention the composition is
affixed with an adhesive.
[0018] In another aspect of the invention the semi-metallic
composition is additionally mechanically affixed.
[0019] In another aspect of the invention, an improved camming
device is provided that has a superior range of operation, is
lighter and has lower internal compressive forces. A camming device
is for use as protection in cracks during rock climbing, and
comprises at least one pair of lobes, one axle per pair of lobes, a
stem, a loop and a release mechanism. The lobes comprise: a face
having a contact area; an inside edge; an apical end; and a basal
end, to define an inner surface and an outer surface. The
improvement comprises a semi-a composition having a co-efficient of
friction ranging between 0.35-0.55 affixed to the contact area.
[0020] In another aspect of the invention the composition is housed
in a recess in the face.
[0021] In another aspect of the invention the recess extends
substantially from the apical end to the basal end
[0022] In another aspect of the invention the recess terminates in
a tab at the apical end and a tab at the basal end.
[0023] In another aspect of the invention the co-efficient of
friction is in the range of 0.45-0.55.
[0024] In another aspect of the invention the co-efficient of
friction is about 0.46.
[0025] In another aspect of the invention, the composition is
comprised of a metal selected from the group consisting of
aluminum, copper, bronze and brass.
[0026] In another aspect of the invention, the composition is a
semi-metallic composition.
[0027] In another aspect of the invention the composition is
affixed with an adhesive.
[0028] In another aspect of the invention the composition is
additionally mechanically affixed.
[0029] In yet another aspect of the invention, an improved method
of fall protection cracks during rock climbing is provided. The
method comprises employing a camming device having a maximum range
of about 0.9''-1.18''.
[0030] In another aspect of the invention the maximum range is
about 1.0''-1.18''.
[0031] In another aspect of the invention the camming device has a
co-efficient of friction on a contact area between 0.45 and
0.50.
[0032] In another aspect of the invention the camming device has a
co-efficient of friction of about 0.46.
[0033] In another aspect of the invention, a rack of climbing cams
is provided having five camming devices providing an operational
range of approximately 4.0 inches.
[0034] In another aspect of the invention, the rack comprises four
camming devices providing an operational range of approximately 2.6
inches.
[0035] In another aspect of the invention, the rack comprises three
camming devices providing an operational range of approximately 1.7
inches.
[0036] In another aspect of the invention, the camming device has
two axles and two pairs of lobes.
[0037] In another aspect of the invention, the loop comprises a
composite cord.
[0038] In another aspect of the invention, a method of
manufacturing an improved a camming device is provided. The camming
device is comprised of at least one pair of lobes, one axle per
pair of lobes, a stem, a loop and a release mechanism, the lobes
comprising: a face having a contact area; an inside edge; an apical
end; and a basal end, to define an inner surface and an outer
surface. The method comprises increasing the static co-efficient of
friction on a contact area by affixing a semi-metallic composition
to the contact area.
[0039] In another aspect of the method, the semi-metallic
composition is housed in a recess in the face.
[0040] In another aspect of the method, the recess extends
substantially from the apical end to the basal end.
[0041] In another aspect of the method, the recess terminates in a
tab at the apical end and a tab at the basal end.
[0042] In another aspect of the method the semi-metallic
composition has a co-efficient of friction is in the range of
0.35-0.55.
[0043] In another aspect of the method the semi-metallic
composition has a co-efficient of friction is in the range of
0.45-0.55.
[0044] In another aspect of the method the semi-metallic
composition has a co-efficient of friction of about 0.46.
[0045] In another aspect of the method the semi-metallic
composition is affixed with an adhesive.
[0046] In another aspect of the method the semi-metallic
composition is additionally mechanically affixed.
[0047] In another aspect of the invention, the method further
comprises utilizing a suitably selected composite cord for
manufacture of the loop.
[0048] In another aspect of the invention, a method of
manufacturing an improved a camming device is provided. The camming
device is comprised of at least one pair of lobes, one axle per
pair of lobes, a stem, a loop and a release mechanism, the lobes
comprising: a face having a contact area; an inside edge; an apical
end; and a basal end, to define an inner surface and an outer
surface. The method comprises increasing the static co-efficient of
friction on a contact area by affixing a composition having a
co-efficient of friction in the range of 0.40-0.55 to the contact
area.
[0049] In another aspect of the method, the composition is housed
in a recess in the face.
[0050] In another aspect of the method, the recess extends
substantially from the apical end to the basal end.
[0051] In another aspect of the method, the recess terminates in a
tab at the apical end and a tab at the basal end.
[0052] In another aspect of the method the composition has a
co-efficient of friction is in the range of 0.35-0.55.
[0053] In another aspect of the method the composition has a
co-efficient of friction is in the range of 0.45-0.55.
[0054] In another aspect of the method the composition has a
co-efficient of friction of about 0.46.
[0055] In another aspect of the method the composition is affixed
with an adhesive.
[0056] In another aspect of the method the composition is
additionally mechanically affixed.
[0057] In another aspect of the invention, the method further
comprises utilizing a suitably selected composite cord for
manufacture of the loop.
FIGURES
[0058] FIG. 1 is a perspective view of a camming device in
accordance with an embodiment of the invention.
[0059] FIG. 2 is an exploded view of the camming device of FIG.
1.
[0060] FIG. 3A and B are drawings of the radius of the extended and
contracted camming device of FIG. 1.
[0061] FIG. 4 is a perspective view of a lobe of the camming device
of FIG. 1.
DETAILED DESCRIPTION OF THE INVENTION
[0062] A camming device for climbing, generally referred to as 10,
is shown in FIG. 1. The camming device 10 has two cams 12 in
parallel relation to each other, each comprising two lobes, an
inner lobe 14 and an outer lobe 16, for engaging a crack when
actuated. The lobes 14, 16 are aluminum. The two cams 12 are
rotatably mounted on a stainless steel axle 18, by means of a bore
20, such that inner lobes 14 oppose one another and the outer lobes
16 oppose one another as shown in FIG. 2. The lobes 14, 16 define a
radius that expands as the camming device 12 is actuated, as shown
in FIG. 3A and B. Each lobe 14, 16 is generally triangular and has
a face 22, and an inside edge 24 terminating at an apical end 26,
and a basal end 28 opposing the apical end 26 as shown in FIG. 4.
An inner surface 30 and outer surface 32 are defined by the face
22, edge 24 and ends 26, 28. The face 22 has a logarithmic contact
shape, with the contact area 34 comprising a semi-metallic
composition. The semi-metallic composition is brake pad material,
having a static coefficient of friction of about 0.46 when
contacted with rock. The semi-metallic composition on the contact
area 34 is affixed using adhesive and is housed in a recess 36 of
the lobe 14, 16 with tabs 38, 40 extending from the apical end 26
of the lobe 14, 16 and the basal end 28, of the lobe 14, 16 as
shown in FIG. 4. The semi-metallic composition increases holding
power, allows for an increased operational range and lowers
internal compressive forces. A stop 42 subtends the recess 36 in
the vicinity of the basal end 28 and protrudes from the inner
surface 30 of the outer lobe 16 and the outer surface 32 of the
inner lobe 14, such that the stop 42 of one lobe 14 abuts the basal
end 28 of the other lobe 16, when the camming device 10 is fully
retracted. In this position, the camming device 10 may function as
passive protection.
[0063] The axle 18 is retained in the bore 20 of the lobes 14, 16,
by means of a hub 44 on either end 46 of the axle 18. Between the
pairs of cams 12, a stem 48 comprising a composite cord made of
Parallay.TM. construction HMPE fibre is rotatably mounted on the
axle 18. A washer 47 is located on the axle 18 between the stem 48
and each inner lobe 14. A loop 50 is affixed to a distal end 52 of
the stem 48 by splicing. A guide, 51, is rotatably mounted on the
axle 18 and accepts the stem 48.
[0064] A release mechanism 56 is slidably mounted on the stem 48 by
a plate 58 with a centrally located release bore 60, through which
the stem 48 slides. Adjacent the release bore 60 on either side of
the release bore 60 are a pair of bores 64 through which a
resilient member, such as a cable 66 is threaded. The cable 66 is
aligned such that the distance between the two lobes 14, 16 and the
plate 58 is the same. Each lobe 14, 16 has an aperture 54 to accept
the cable 66. The aperture 54 on the outer lobe 16 is on the outer
surface 32 and the aperture 54 on the inner lobe 14 is also on the
outer surface 32. The cable 66 of the release mechanism 56 is
rotatably within the aperture 54.
[0065] The lobes 14, 16 are biased from one another in a cam 12 by
biasing means, such as a spring 68. Hence, when downward pressure
is exerted on the camming device 10, the cams 12 spring open into
an actuated position, in which the face 22 with its contacting
surface 34, engages a crack by abutting opposing rock walls of the
crack. When the climber wants to release the camming device 10 from
the crack, he pulls the plate 58 of the release mechanism 56 away
from the rock while pushing the stem 48 in towards the rock, and
the camming device 10 is released. The camming device 10 is then
returned to a rack of camming devices.
EXAMPLE 1
[0066] Detailed friction testing of five advanced composite
friction materials against 8 different types of rock, laboratory
testing of twelve different two-part adhesives (including expoxies,
acrylics and urethanes) for break away and internal strength and
extensive research into new market products, in terms of cords,
heat shrink tubing and metal based putties was carried out. This
led to inventing a camming device with an 81.3% increase in the
standard working range and a 34.5% reduction in stem weight.
TABLE-US-00001 TABLE 1 Friction Material Testing Co-Efficient of
Friction (.mu.) (Frictional Force/Normal Force) AFT- AFT- Al- F4-3-
Friction Materials HF-61 9010 1006 200 6106 252 Rock Types Black
Sandstone 0.38 0.58 0.45 0.35 0.48 0.38 Green Sandstone 0.48 0.41
0.62 0.53 0.53 0.64 Yellow Quartzite 0.59 0.62 0.62 0.55 0.52 0.55
Pink Quartzite 0.63 0.61 0.66 0.06 0.42 0.58 Gneiss 0.53 0.66 0.56
0.47 0.42 0.46 Basalt 0.33 0.55 0.33 0.39 0.34 0.45 Limestone 0.43
0.55 0.27 0.39 0.36 0.23 White Granite 0.67 0.67 0.51 0.54 0.45
0.43 Average Co-Efficient 0.51 0.58 0.50 0.41 0.44 0.47 of Friction
Claimed Co-Efficient 0.61 0.46 0.52 0.42 0.31 0.41 of Friction
Corrected Test Values 0.36 0.41 0.35 0.29 0.31 0.33
[0067] The introduction of a high frictional co-efficient material
to the rock/lobe interface increases the frictional forces of the
cam. This increased holding power allows for an increased
operational range and lower internal compressive forces. The
operational ranges for a set of cams of the present invention is
shown in Table 3. The increase in range for #6 Trango cam is 0.35''
this corresponds to a 49.3% increase. The increase in range for a
#7 Trango cam=1.36'' which translates to an 81.3% increase.
TABLE-US-00002 TABLE 3 Cam operational ranges Cam Trango Improved
cam #6 1.38 to 2.09 1.56 to 2.62 #7 1.89 to 2.64 2.60 to 3.96 #8
2.40 to 3.58 *All in inches*
[0068] The lobe shape of the cam is a logarithmic spiral defined
as: r=e.sup.c.theta. [0069] Where: r=radius of spiral [0070]
e=natural logarithm [0071] c=coefficient defining how fast the
spiral opens [0072] .theta.=angle measured in radians
[0073] The coefficient c, in equation (1) is limited by the
coefficient of friction between the rock and the lobe interface.
The claimed 0.42 coefficient of friction for material 9010 was used
for the coefficient c in the lobe shape equation. Trango.TM. #7
(size 7 in Trango's range of cams) cam was used in the prototype
model of the camming device, so the lobe size coefficient which
factors the lobe equation to determine size is 0.515. This
coefficient ensures that the vertical distance from the axle to the
lobe surface is 1.00'', the distance for Trango cams. FIGS. 3A and
B show an extended and a contracted cam lobe, demonstrating the
range dimensions of the lobes for extended and contracted
positions, respectively. The specified range of Trango's #7 Flex
cam is 1.89'' to 2.64'' for a maximum range of about 0.75''. As
shown in FIGS. 3A and B, the improved range is 2.60'' to 3.96'' for
a maximum range of about 1.36''. The range of the improved camming
devices of the present invention are shown relative to Trango
camming devices. It can be seen from Table 3 that the range of the
camming devices are significantly greater and hence, fewer camming
devices are needed to cover the range of sizes. As would be known
to one skilled in the art, the range is determined from a
logarithmic equation, hence the percentage change in range will be
exponential. For example, after detailing another cam of Trango's
(the #6), the range increase was found to be 49.3%. This reduces
the number of camming devices needed for a given rack.
TABLE-US-00003 TABLE 2 Adhesives Evaluated Product Item Batch
Number Number Number Product Description 326/7649 32629/ 2IP228B/
18,000 cP, amber, two-part no-mix 38402 3IV8700D urethane
methacrylate acrylic adhesive. E-05CL 29299 3I29723A 1,900/2,800
cP, ultra clear, 5 minute work life, two-part mercaptan epoxy.
U-05FL 29348 3AZ9618A 640/35,000 cP, off white, 5 minute work life,
two-part polyurethane adhesive.
[0074] The foregoing is a description of an embodiment of the
invention. As would be known to one skilled in the art, there can
be variations in design of the camming device that do not change
the scope of the invention. For example, the camming device can be
a single cam or double cam device. The plate of the release
mechanism may be machined or forged metal, or may be injection
moulded and comprise a polymeric material. The stops may be
contoured flush with the face of the lobe. The composite cord can
be comprised of, for example, but limited to non-metallic advanced
climbing or sailing materials and can be spliced, knotted, sewn,
glued, or mechanically fastened to form a loop. The cord is the
main tensile load bearing member of the camming device. Suitable
materials and means of fastening would be known to one skilled in
the art. A protective sheath can surround the loop in the stem. The
semi-metallic composition may be affixed to the face of the lobe by
mechanical means or by a combination of mechanical and adhesive
means. Further, a ceramic composition might replace the
semi-metallic composition, and this would alter the coefficient of
friction accordingly. Still further, the semi-metallic composition
can be replaced with soft metals, such as, but not limited to
Aluminum 5052 and 3003, coppers, brasses, and bronzes, that have a
co-efficient of friction of about 0.35 and higher. The coefficient
of friction can range from about 0.35-0.55. These and other
modifications are within the scope of the invention.
* * * * *