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DESCRIPTION
CANE AND CYLINDRICAL BODY
TECHNICAL FIELD
The present invention relates to a cane such as a white cane
for the visually disabled. More particularly, the present
invention relates to a cane that has a sufficient
impact-resistant strength against a force in a direction
perpendicular to the axis of its shaft; and is excellent in
safety, durability and repairability and also lightweight but
has a high stiffness.
BACKGROUND ART
A cane is also called a stick or a pole, and used not only
by the visually disabled and people with limb disabilities, such
as elderly people, but also by healthy people for trekking,
light mountain climbing, etc. Such a cane usually has a
rod-shaped shaft, a grip which is designed for the user to grasp
and formed at the upper end of the shaft, and a ferrule attached
to the lower end of the shaft. Conventional canes, although
are more or less structurally different from each other, are
made of wood, an aluminum alloy, etc. in the most cases.
For example, a so-called white cane for the visually
disabled is usually used with its tip slightly lifted from the
ground for a prolonged period, and thus weight saving is desired,
but conventional wooden canes are heavy and give a heavy burden
to the users.
Furthermore, such wooden canes are
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unsatisfactory in strength, and may be repeatedly swelled and
dried by environmental changes, resulting in undesired warpage
of the shaft and detachment of the superficial coating thereof.
Aluminum alloy canes are more lightweight than wooden canes,
but still heavy for prolonged use and disadvantageously tend
to dent and bend in response to impact.
Meanwhile, a cane having a shaft made of a carbon
fiber-reinforced resin is recently proposed (for example, see
Patent Literature 1) . The cane having such a shaft is more
lightweight than conventional wooden canes and aluminum alloy
canes and is resistant to undesired warpage and corrosion.
However, the cane according to Patent Literature 1, although
is more lightweight than conventional canes made of wood, an
aluminum alloy, etc., is not lightweight enough, particularly
to allow the visually disabled etc. to use for a prolonged period,
and thus further weight saving is desired.
The above-mentioned cane having a shaft made of a carbon
fiber-reinforced resin has, due to the high tensile strength
and elastic modulus of carbon fibers, such a high flexural
modulus as applied to, for example, a golf shaft. However,
since carbon fibers as inorganic fibers have a low elongation
and lack flexibility, the shaft disadvantageously tends to
break in response to an impact in a direction transverse to the
shaft (flexural impact) . Considering this, the
above-mentioned shaft has a sufficient mechanical strength as
a golf shaft in striking, but is unsatisfactory as a cane shaft.
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This is because a cane using this shaft is given an impact when
the user frequently hits the road surface and obstacles with
the cane in order to examine their conditions, and the impact
is transmitted to the shaft via the ferrule and may cause
microcracks in the carbon fiber. Thus, when given an external
force by bumps (against a person, a bicycle and other obstacles) ,
etc., the cane may easily fracture at the site where cracks have
been generated. Therefore, development of a cane having a
sufficient strength (flexural stiffness) against a force in a
transverse direction, namely a direction perpendicular to the
axis of its shaft is desired.
Further, the above-mentioned cane having a shaft made of
a carbon fiber-reinforced resin may fracture in response to
impact etc., be heavily damaged on the fracture surface, and
have spiky ends of stiff fibers projected from the fracture
surface. In this case, for example, when the visually disabled
check the fracture site and the damage level, naturally by touch,
the fibers exposed on the fracture surface may get stuck in the
hand. Therefore, the above-mentioned cane needs to be
thicker-walled so as not to easily fracture at the time of impact
etc., but in this case, the weight of the cane is increased.
Further, the repairability of the above-mentioned cane is
unsatisfactory because the fracture site is damaged so heavily
that simple repair on site is difficult. Thus, development of
a cane that can be easily repaired on site has been desired.
The above-mentioned disadvantages can be overcome, for
example, by forming a shaft using a high-strength organic
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fiber-reinforced resin composed of a para-aramid fiber, an
epoxy resin and the like. However, such a shaft is excellent
in impact resistance but has a lower stiffness compared with
the shaft formed of a carbon fiber-reinforced resin. This
stiffness of the shaft can be enhanced by thickening the layer
of the high-strength organic fiber-reinforced resin, but in
this case, the shaft is thicker, the amount of the resin used
is increased and the weight of the cane is excessively
increased.
[Citation List]
[Patent Literature]
Patent Literature 1: JP-A 2005-218473
SUMMARY OF INVENTION
TECHNICAL PROBLEM
A technical problem to be solved by the present invention
is to provide a cane that is free from the above-mentioned
disadvantages; has a sufficient impact-resistant strength
against a force in a direction perpendicular to the axis of its
shaft; and is excellent in safety, durability and repairability
and also lightweight but has a high stiffness.
SOLUTION TO PROBLEM
As a solution to the above-mentioned problem, the present
invention has, for example, the following constitutions, which
will be described based on Figs. 1 to 18 showing embodiments
of the present invention.
That is to say, the present invention relates to a cane
having a shaft (4) and a grip (1) provided at the upper end of
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the shaft (4), the shaft (4) comprising a
high-strength-organic-fiber-reinforced-resin layer (31) and a
carbon-fiber-reinforced-resin layer (32), the
high-strength-organic-fiber-reinforced-resin layer (31)
5 being integrally laminated onto at least the outside surface
of the carbon-fiber-reinforced-resin layer (32).
The present invention 2 is a cylindrical body, comprising
a cylindrical high-strength-organic-fiber-reinforced-resin
layer (31) and a cylindrical carbon-fiber-reinforced-resin
layer (32), the high-strength-organic-fiber-reinforced-resin
layer (31) being integrally laminated onto at least the outside
surface of the carbon-fiber-reinforced-resin layer (32).
The organic fiber which constitutes the
high-strength-organic-fiber-reinforced-resin layer is
lightweight but has a high tensile strength. Also, since
organic fibers have a higher elongation compared with inorganic
fibers such as carbon fibers, for example, even when the user
hits the ground etc. with the tip of the cane, there is no
possibility of impact-triggered microcrack generation in the
organic fiber. Further, when the shaft or the cylindrical body
is given an impact in a direction perpendicular to the axial
direction (flexural impact), the
high-strength-organic-fiber-reinforced-resin layer buckles
and deforms without fracturing, and buffers this impact.
The carbon-fiber-reinforced-resin layer in each of the
shaft and the cylindrical body has a high stiffness since carbon
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fibers have a higher elastic modulus than that of organic fibers,
and thus the high-strength-organic-fiber-reinforced-resin
layer does not have to be excessively thick.
Carbon fibers themselves easily break in response to
flexural impact, but since the carbon-fiber-reinforced-resin
layer has a high- strength-organic- fiber- reinforced-resin
layer integrally laminated onto the outside surface and is
protected thereby, even if carbon fibers break in response to
an impact in a direction perpendicular to the axis of the shaft
or the cylindrical body, the shaft or the cylindrical body only
buckles and deforms without heavily fracturing, and broken
spiky carbon fibers are prevented from projecting from the
fracture site. In addition, a cane buckled and deformed in the
shaft etc. can be easily repaired by use of, for example, a
commercial repair kit etc.
The high-strength-organic-fiber-reinforced-resin layer is
integrally laminated onto at least the outside surface of the
carbon-fiber-reinforced-resin layer, and may be integrally
laminated onto each of the outside and inside surfaces. The
latter case is preferable since
the
carbon-fiber-reinforced-resin layer is sandwiched in between
the inner and outer
high- strength-organic- fiber- reinforced- resin layers and
protected thereby much more favorably, and thus fracture of the
shaft or the cylindrical body is prevented.
The high-strength organic fiber is not limited to specific
kinds as long as it has a high mechanical strength (for example,
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tensile strength), etc. Examples thereof include
ultra-high-molecular-weight-polyethylene fibers,
wholly-aromatic polyamide fibers, wholly-aromatic polyester
fibers, heterocyclic high-performance fibers and polyacetal
fibers. These fibers can be used alone or as a mixture formed
of two or more kinds at any ratio. Specifically, para-aramid
fibers are preferably used and poly(p-phenylene
terephthalamide) fibers are particularly preferable.
The shaft and the cylindrical body each comprise at least
one carbon-fiber-reinforced-resin layer and at least one
high-strength-organic-fiber-reinforced-resin layer, and one
or both of the carbon-fiber-reinforced-resin layer and the
high-strength-organic-fiber-reinforced-resin layer may be
plural. It is also possible that the shaft and the cylindrical
body each consist of these layers. However, it is preferable
that the shaft comprises a
cylindrical
glass-fiber-reinforced-resin layer on the inner side of the
innermost high-strength-organic-fiber-reinforced-resin layer.
One reason for this is that such a constitution can provide a
favorable wear resistance of the inner surface. Another reason
is that, when the shaft or the cylindrical body is cut into pieces
of a predetermined length etc., such a constitution can prevent
organic fibers from raveling on the inner surfaces of the cut
ends and keep the cut ends in a favorable shape.
It is also preferable that the shaft comprises a cylindrical
glass-fiber-reinforced-resin layer on the outer side of the
outermost high-strength-organic-fiber-reinforced-resin layer.
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One reason for this is that such a constitution can provide a
favorable wear resistance of the outer surface. Another reason
is that, when the shaft or the cylindrical body is cut into pieces
of a predetermined length etc., such a constitution can prevent
organic fibers from raveling on the outer surfaces of the cut
ends and keep the cut ends in a favorable shape.
For function as an external indicator to help, for example,
the visually disabled to recognize the location and the function
of the cane, or for decoration etc., the shaft preferably
comprises an indicating layer on the outer side of the outermost
high-strength-organic-fiber-reinforced-resin layer. The
indicating layer may be a coating film of any color, pattern
or the like, but is preferably a reflective tape, a red-colored
tape, etc. because such tapes enable easy formation of the
indicating layer in a predetermined color etc., easy repair
thereof and the like.
The indicating layer on the outer surface of the shaft may
be externally exposed, but it is preferable that a cylindrical
glass-fiber-reinforced-resin layer or a wear-resistant
transparent resin layer is provided on the outer side of the
indicating layer. This is because that the indicating layer
protected by such a glass-fiber-reinforced-resin layer or
wear-resistant transparent resin layer has an increased wear
resistance and water resistance and can also be prevented from
changing in color and getting detached from the shaft.
The cross-sectional shape of the shaft is not limited to
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specific kinds and may be an odd shape, but is preferably a
circular shape. Examples of the odd shape include an oval shape,
a hollow shape, an X shape, a Y shape, a T shape, an L shape,
a star shape, a leaf shape (for example, a 3-leaf shape, a 4-leaf
shape, a 5-leaf shape, etc.) and other multangular shapes (for
example, a triangular shape, a square shape, a pentagonal shape,
a hexagonal shape, etc.) .
The shaft may be solid unless the effects of the present
invention are hindered, but in terms of weight saving of the
cane, it is preferable that the shaft is a hollow structure
composed of a hollow and a shell surrounding the hollow. In
the cross-section perpendicular to the axis of the shaft, the
cross-sectional area ratio of the hollow and the shell is not
limited to specific values unless the ratio hinders the effects
of the present invention. In order that the shaft may have a
sufficient strength against a force perpendicular to the axial
direction and be so lightweight as to allow prolonged use, the
cross-sectional area ratio is preferably 85:15 to 56:44, and
further considering excellent safety and repairability, the
cross-sectional area ratio is more preferably 80:20 to 60:40,
and particularly preferably 75:25 to 62:38. When the
cross-sectional area ratio of the hollow to the whole of the
shaft is less than 56%, the cane is not sufficiently lightweight
and has such a hard shaft to tend to make the user exhausted
in prolonged use, and therefore this case is not preferable.
Conversely, when the cross-sectional area ratio of the hollow
to the whole of the shaft exceeds 85%, the cane is too lightweight
and does not have a sufficient strength against a force
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perpendicular to the axial direction, and therefore this case
is not preferable, either.
The cane may be a non-foldable, so-called, straight cane
5 having a shaft formed of one cylindrical body etc. Such a shaft
without junctions etc. is lightweight and thus is preferable.
Alternatively, the cane of the present invention may be a
so-called folding cane having a shaft composed of a plurality
of shaft parts. Such a cane, while not in use, can be folded
10 up into a size compact enough to easily carry and thus is also
preferable.
In the case of the above-mentioned folding cane, the shaft
is composed of a plurality of mutually connectable and separable
shaft parts, and in the shaft parts adjacent to each other, a
first connecting end of one shaft part is provided with a
smaller-diameter part that can be inserted into and removed from
a second connecting end of the opposite shaft part. In this
case, the number of shaft parts, i.e., the number of folds is
not limited to specific numbers, and depending on the cane
length and the folded dimensions, may be any appropriate number,
for example, 5 to 7. The smaller-diameter part may be produced
separately from the shaft part and attached thereto with an
adhesive, or be formed integrally with the connecting end of
the shaft part. The adhesive may be a known adhesive and is
not particularly limited.
The material of the smaller-diameter part is not limited
to specific kinds, but it is preferable that the
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smaller-diameter part is formed of a
high-strength-organic-fiber-reinforced-resin layer as used
for the shaft because this
high-strength-organic-fiber-reinforced-resin layer can
favorably reinforce the junction(s) of shaft parts and
effectively prevent fracture at the junction(s), which is
susceptible to stress. It is more preferable that the
smaller-diameter part is formed of only a
high-strength-organic-fiber-reinforced-resin layer composed
of a para-aramid fiber and the like.
Preferably, the folding cane comprises a cylindrical joint
cover to cover the first connecting end and the second
connecting end which are connected to each other, one end of
the joint cover being fitted onto one of the first and second
connecting ends and fixed thereto, the other end of the joint
cover being configured such that the other connecting end can
be inserted thereinto and removed therefrom. This is
advantageous because such a joint cover can tightly hold the
ends of these shaft parts connected to each other and does not
allow any backlash.
The shape of the grip is not particularly limited unless
the shape hinders the effects of the present invention, and
examples thereof include an I shape and a T shape. The grip
maybe composed of only resin, or formed by coating the outside
of any core with resin. The grip is preferably hollow
structured in terms of weight saving, and in this case, a hollow
structured core may be used.
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The resin used for the grip is not particularly limited
unless the resin hinders the effects of the present invention.
Examples thereof include polyester resins, polyamide resins
(for example, nylons such as nylon 6, 66 nylon and MC nylon),
acrylate resins, ABS resins, polyolefin resins (for example,
polypropylene resins, polyethylene resins, etc.),
polybutylene terephthalate resins and polyethylene
terephthalate resins. Fiber-reinforced resins may be also
used. Examples of the material used for the core include
silicone and nylon. In particular, it is preferable that the
grip is formed of, for example, the same materials as those of
the shaft, namely a carbon fiber-reinforced resin and a
high-strength organic fiber-reinforced resin, because such a
grip is lightweight, highly strong and producible at low cost.
The dimensions such as the length and diameter of the grip
are appropriately determined if needed. The production method
of the grip is not particularly limited and known methods can
be used. Commercial products may be also used.
Preferably, the grip has a hollow-structured grip body
extended from the upper end of the shaft, the cross-section
perpendicular to the axis of the grip body being larger than
that of the shaft. This is advantageous because such a grip
is lightweight but thick enough for the user to firmly grasp.
The outer surface of the grip body may be externally exposed
as it is, or be in an antislip shape such as uneven patterns.
However, it is preferable that the grip has an antislip member
on at least part of the outer surface of the grip body etc.,
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the antislip member being a coating layer formed of rubber, a
synthetic resin, etc. or being a commercial grip tape or the
like. This is advantageous because the user can securely grasp
such a grip.
A ferrule may be provided at the lower end of the shaft.
The shape and material of the ferrule are not limited to specific
kinds, but it is preferable that the ferrule is formed of a
high-strength organic fiber-reinforced resin in which staple
fibers of a high-strength organic fiber are dispersed in a
synthetic resin, because such a ferrule is excellent in usage
characteristics and wear resistance.
That is to say, in the case of a cane having a ferrule formed
of such a high-strength organic fiber-reinforced resin, when
the user, while walking, lightly hits and traces the road
surface with the tip of the cane in order to examine the
conditions thereof, the ferrule favorably reacts against the
objects. For example, when the ferrule touches the road surface,
the ferrule lightly bounces back therefrom and transmits
information such as the degree of bouncing-back movement, a
sound generated when the ferrule hits the road surface, and a
feel given when the ferrule moves along the road surface, and
such information clearly varies with the kind and material of
the road surface such as an asphalt pavement and a concrete
pavement. Such a movement and the like are considered to be
influenced collectively by various characteristics of the
ferrule, such as hardness, density, elastic coefficient,
frictional resistance and wear resistance, based on the
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material of the ferrule.
Accordingly, a cane having such a ferrule is advantageous
because the cane can clearly transmit information to the user,
regarding not only obstacles and unevenness on the road surface
but also detailed unevenness, feels of materials, etc., so as
to enable more accurate recognition of the kind of the road
surface toward the walking direction etc., and therefore the
visually disabled can walk more safely with a sense of great
security. More advantageously, since the ferrule favorably
reacts against objects to be examined, the necessity of
excessively swinging around the cane or poking about therewith
is reduced and the burden to the user's hand and wrist is
reducible. More advantageously, the sound generated when the
cane hits objects to be examined is not so loud, and thus the
manipulability is excellent. From the above, it is understood
that the cane is excellent in usage characteristics and
particularly preferable as a white cane for the visually
disabled because the cane favorably works as a sensor, and that
the cane is also lightweight and excellent in durability.
The high-strength organic fiber content of the
high-strength organic fiber-reinforced resin is not limited to
specific amounts. However, when the content is too small, usage
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The high-strength organic fiber is not limited to specific
kinds as long as it has a high mechanical strength (for example,
tensile strength), etc. Examples thereof include
5 ultra-high-molecular-weight-polyethylene fibers,
wholly-aromatic polyamide fibers, wholly-aromatic polyester
fibers, heterocyclic high-performance fibers and polyacetal
fibers. These fibers can be used alone or as a mixture formed
of two or more kinds at any ratio. Specifically, para-aramid
10 fibers are preferably used, and because of the properties of
being easily fibrillated and dispersible, poly(p-phenylene
terephthalamide) fibers are particularly preferable.
The high-strength organic fiber is dispersed as a staple
15 fiber in the synthetic resin. The thickness and length of the
staple fiber are not limited to specific values as long as the
staple fiber can be dispersed in the synthetic resin. Inter
alia, a high-strength organic fiber with a filament fineness
of about 1.1 to 2.3 dtex and with a fiber length of about 2 to
8 mm can favorably disperse and thus is preferable. Further,
such a high-strength organic fiber can sufficiently deliver
usage characteristics, wear resistance, etc. required for
ferrules.
The synthetic resin is not limited to specific kinds as long
as it can disperse high-strength organic fibers and be formed
into a ferrule, but is preferably a thermoplastic synthetic
resin in terms of easy shaping. Specific examples thereof
include polyester resins, polyamide resins ( for example, nylons
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such as 6 nylon, 66 nylon and MC nylon), acrylate resins, ABS
resins, polyolefin resins (for example, polypropylene resins,
polyethylene resins, etc.), polybutylene terephthalate resins
and polyethylene terephthalate resins. Polyamide resins are
particularly preferable because of their excellent wear
resistance.
ADVANTAGEOUS EFFECTS OF INVENTION
The present invention, which has constitutions and
functions as described above, exhibits the following effects.
(1) Since the carbon-fiber-reinforced-resin layer has a high
stiffness, even when given a force in the axial direction, the
shaft does not curve or bend, and thus the user can use the cane
with a sense of security.
(2) Since the high-strength-organic-fiber-reinforced-resin
layer is excellent in vibration damping, vibration etc. of the
tip of the cane can be accurately transmitted to the user's hand.
(3) Since a
lightweight
high-strength-organic-fiber-reinforced-resin layer and a
highly stiff carbon-fiber-reinforced-resin layer are
comprised in combination, the shaft and the cylindrical body
each have a high strength and are lightweight without the need
of an excessively thick
high-strength-organic-fiber-reinforced-resin layer.
(4) Since the high-strength-organic-fiber-reinforced-resin
layer is comprised, even when the user hits the ground,
obstacles, etc. with the tip of the cane, there is no possibility
of impact-triggered microcrack generation in the high-strength
organic fiber, and thus the durability is excellent.
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(5) Even when a great flexural impact is applied in a direction
perpendicular to the axial direction, the
high-strength-organic-fiber-reinforced-resin layer can
buffer the impact by buckling deformation, deliver an excellent
performance in mechanical strength such as impact resistance,
and thus favorably prevent the shaft from fracturing.
(6) Even if carbon fibers break in response to a great flexural
impact in a direction perpendicular to the axial direction, the
carbon-fiber-reinforced-resin layer is protected by the
high-strength-organic-fiber-reinforced-resin layer
integrally laminated onto the outside surface thereof, and thus
heavily fracturing is prevented. Broken spiky carbon fibers
are also prevented from projecting from the site to which the
flexural impact has been given. Accordingly, for example, the
visually disabled etc. can safely check such a damaged site by
touch or the like.
(7) Since each of the shaft and the cylindrical body does not
easily fracture even when given a great flexural impact in a
direction perpendicular to the axial direction, they can be
easily repaired by use of, for example, a commercial repair kit
etc., for example, at the venue where the impact has been given,
and the repaired cane etc. can be continuously used.
BRIEF DESCRIPTION OF DRAWINGS
Fig. 1 shows a first embodiment of the present invention,
Fig. 1 (a) is an outline view of a straight cane, and Fig. 1
(b) is an A-A arrowed cross-sectional view of Fig. 1 (a). An
outline view of a straight cane is shown.
Fig. 2 is a partially cutaway view showing the laminated
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structure of the shaft according to the first embodiment.
Fig. 3 is a partially cutaway view of the grip of the cane
according to the first embodiment.
Fig. 4 is a partial cutaway and perspective view showing
the vicinity of the ferrule of the cane according to the first
embodiment.
Fig. 5 is a partially cutaway view showing the laminated
structure of the shaft according to a second embodiment of the
present invention.
Fig. 6 shows a third embodiment of the present invention,
Fig. 6 (a) is an outline view of a folding cane, and Fig. 6 (b)
is an enlarged sectional view of part B in Fig. 6 (a) .
Fig. 7 is an outline view of the cane in a folded state
according to the third embodiment.
Fig. 8 is a sectional view of the vicinity of the joint cover
of the cane in an unconnected state according to the third
embodiment.
Fig. 9 is a sectional view of the vicinity of the joint cover
of the cane in a connected state according to the third
embodiment.
Fig. 10 is an outline view of the grip according to modified
example 1 of the present invention.
Fig. 11 is a segmentary view of the vicinity of the ferrule
according to modified example 2 of the present invention.
Fig. 12 is a perspective view showing the emergency repair
kit used for the repairability test.
Fig. 13 is a perspective view showing the state of the main
part of the cylindrical body in the repairability test.
Fig. 14 is comparison table 1 showing the measurement
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results of each characteristic value of the shaft of the present
invention in comparison with Comparative Examples.
Fig. 15 is a schematic view of the measuring device used
for measurement of the wear resistance of the outer surface of
the shaft.
Fig. 16 shows the road surfaces used for examination of the
usage characteristics of the ferrule, Fig. 16 (a) is an image
of an asphalt pavement, Fig. 16 (b) is an image of a concrete
pavement arranged with gravels on the surface, and Fig. 16 (c)
is an image of a concrete pavement with a tiled pattern.
Fig. 17 is comparison table 2 showing the measurement
results on the usage characteristics of the ferrule of the
present invention in comparison with Comparative Examples.
Fig. 18 is comparison table 3 showing the measurement
results on the wear property of the ferrule of the present
invention in comparison with Comparative Examples.
DESCRIPTION OF EMBODIMENTS
Hereinafter, the present invention will be described in
detail based on the drawings.
As shown in Fig. 1 (a), a cane (7) of a first embodiment
has a shaft (4), a grip (1) provided at the upper end of the
shaft (4), and a ferrule (6) fixedly attached to the lower end
of the shaft (4).
As shown in Fig. 1 (b), the shaft (4) is in the shape of
a hollow cylinder of which the cross-section perpendicular to
the axis is in a circular shape. As shown in Fig. 2, the shaft
(4) comprises a
cylindrical
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high-strength-organic-fiber-reinforced-resin layer (31), a
cylindrical carbon-fiber-reinforced-resin layer (32), and a
cylindrical glass-fiber-reinforced-resin layer (33).
That is to say, a first
5 high-strength-organic-fiber-reinforced-resin layer (31a) is
integrally laminated onto the inside surface of the
carbon-fiber-reinforced-resin layer (32), and a cylindrical
first glass-fiber-reinforced-resin layer (33a) is integrally
laminated onto the inside surface of the first
10 high-strength-organic-fiber-reinforced-resin layer (31a).
Further, a second
high-strength-organic-fiber-reinforced-resin layer (31b) is
integrally laminated onto the outside surface of the
carbon-fiber-reinforced-resin layer (32), and a cylindrical
15 second glass-fiber-reinforced-resin layer (33b) is integrally
laminated onto the outside surface of the second
high-strength-organic-fiber-reinforced-resin layer (31b).
As shown in Figs. 1 and 2, to the outside surface of the
20 second glass-fiber-reinforced-resin layer (33b), which is
laminated onto the outside surface of the second
high-strength-organic-fiber-reinforced-resin layer (31b), a
white reflective tape (15) and a red-colored tape (16) are
attached as an indicating layer (34). The outside surface of
the indicating layer (34) is covered with a wear-resistant
transparent resin layer (35). As long as the wear-resistant
transparent resin layer (35) is so excellent in wear resistance,
water resistance, etc. as to effectively protect the indicating
layer (34), the material thereof is not limited to specific
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kinds. Specifically, ionomer resin films, such as HIMILAN
( trade name, manufactured by DU PONT-MITSUI POLYCHEMICALS) , and
others are used as a monolayer or a multilayer.
In the cross-section perpendicular to the axis of the shaft
(4) , the cross-sectional area ratio of a hollow (17) and a shell
(18) surrounding the hollow is not limited to specific values.
In order that the shaft may have a sufficient strength and
stiffness against a force perpendicular to the axial direction
and be so lightweight as to allow prolonged use, the
cross-sectional area ratio is appropriately selected from the
ranges of usually 85:15 to 56:44, preferably 80:20 to 60:40,
and more preferably 75:25 to 62:38.
To prevent the shaft (4) from easily fracturing even when
the shaft (4) is given an impact perpendicular to the axial
direction, for example when a bicycle bumps against the user
of the cane (7) , the impact resistance against a force
perpendicular to the axial direction is preferably such a degree
that an impact energy of 10J or larger is absorbable. In terms
of increased safety and repairability, 15J or larger is more
preferable. The impact resistance can be measured using the
Drop Weight Impact Tester manufactured by Instron (product
name: Drop Weight Impact Tester, Dynatup (registered trademark)
9200 series) , etc., according to the three point flexural test
specified in JIS K 7055:1995 (Testing method for flexural
properties of glass fiber-reinforced plastics) .
The shaft (4) may be a tapered cylindrical body in which
CA 02825701 2013-07-25
22
the outer diameter changes in the direction from one end toward
the other end, but it is preferable that the shaft (4) is a
cylindrical body in which the outer diameter is at constant
length from one end to the other end, because such a shaft (4)
can be easily produced by forming a cylinder of any length and
cutting into pieces of a predetermined dimension.
The high-strength-organic-fiber-reinforced-resin layer
(31) which constitutes the shaft (4) can be produced by a known
method, that is, for example, by impregnating high-strength
organic fibers, such as para-aramid fibers, with resin such as
an epoxy resin, shaping the mixture into a predetermined
cylinder, heating the cylinder, for example, at a temperature
of room temperature to about 130 C for curing of the resin, and
cutting the cured product into pieces of a predetermined length.
The carbon-fiber-reinforced-resin layer (32) and the
glass-fiber-reinforced-resin layer (33) can be similarly
produced.
The organic fiber which constitutes the
high-strength-organic-fiber-reinforced-resin layer (31) is
not limited to specific kinds. For example, any of
ultra-high-molecular-weight-polyethylene fibers,
wholly-aromatic polyamide fibers, wholly-aromatic polyester
fibers, heterocyclic high-performance fibers, polyacetal
fibers and the like can be used alone or in a combination of
two or more kinds.
Examples of the carbon fiber which constitutes the
carbon-fiber-reinforced-resin layer (32) include
CA 02825701 2013-07-25
23
polyacrylonitrile-based carbon fibers and pitch-based carbon
fibers. Examples of the glass fiber which constitutes the
glass-fiber-reinforced-resin layer (33) include alkali glass
fibers, alkali-free glass fibers and low-dielectric glass
fibers. However, the organic, carbon and glass fibers used for
the present invention are not limited to the foregoing examples.
The ultra-high-molecular-weight-polyethylene fiber means
a fiber composed of ultra-high-molecular-weight-polyethylene
resin. Here, a suitable
ultra-high-molecular-weight-polyethylene resin has a
molecular weight of about 200,000 or more, preferably about
600,000 or more, and examples thereof include, besides
homopolymers, copolymers with lower a-olefins having about 3
to 10 carbon atoms such as propylene, butene, pentene and hexene .
In the case of a copolymer of ethylene with an a-olefin, it
is suitable that the ratio of the latter per 1000 carbon atoms
is about 0.1 to 20 molecules, preferably about 0.5 to 10
molecules on average. The method for producing
ultra-high-molecular-weight-polyethylene fibers is disclosed
by, for example, JP-A 55-5228 and JP-A 55-107506, and such
disclosed methods known per se may be used. Commercial products,
such as Dyneema (trade name, manufactured by Toyobo Co., Ltd.),
Spectra (trade name, manufactured by Honeywell International,
Inc.), and HI-ZEX MILLION (trade name, manufactured by Mitsui
Chemicals, Inc.) may be also used as the
ultra-high-molecular-weight-polyethylene fiber.
The wholly-aromatic polyamide fiber is not particularly
CA 02825701 2013-07-25
24
limited and examples thereof include aramid fibers. As the
aramid fiber, para-aramid fibers are preferred. Examples of
the para-aramid fiber include poly(para-phenylene
terephthalamide) fibers (manufactured by DU PONT-TORAY CO.,
LTD., trade name: KEVLAR 29, 49, 149, etc.) and
copoly(p-phenylene-3,4'-diphenyl ether terephthalamide)
fibers (manufactured by TEIJIN LIMITED, trade name: Technora).
Inter alia, poly(p-phenylene terephthalamide) fibers are
particularly preferred. The wholly-aromatic polyamide fiber
can be produced by a known method or its modified method.
Alternatively, the commercial products as mentioned above may
be also used.
The wholly-aromatic polyester fiber is not particularly
limited and examples thereof include fibers composed of, for
example, a self-condensed polyester made of p-hydroxybenzoic
acid, a polyester made of terephthalic acid and hydroquinone,
or a polyester made of p-hydroxybenzoic acid and
6-hydroxy-2-naphthoic acid. The wholly-aromatic polyester
fiber can be produced by a known method or its modified method.
Alternatively, commercial products such as Vectran (trade name,
manufactured by Kuraray Co., Ltd.) can be also used.
The heterocyclic high-performance fiber is not
particularly limited and examples thereof include
poly(p-phenylene benzobisthiazole) (PBZT) fibers and
poly(p-phenylene benzobisoxazole) (PBO) fibers. The
heterocyclic high-performance fiber can be produced by a known
method or its modified method. Alternatively, PBO fibers such
CA 02825701 2013-07-25
as Zylon (trade name, manufactured by Toyobo Co., Ltd.) and the
like can be also used.
The polyacetal fiber is not particularly limited and can
5 be produced by a known method or its modified method.
Alternatively, commercial products such as Tenac (trade name,
manufactured by Asahi Kasei Corporation) and Dirline (trade
name, manufactured by Du Pont) can be also used.
10 The resin
with which the above-mentioned high-strength
organic fibers, carbon fibers or glass fibers are impregnated
is not particularly limited unless the resin hinders the effects
of the present invention. Examples thereof include
thermosetting resins such as epoxy resins, unsaturated
15 polyester resins and vinyl ester resins. Thermoplastic resins
are also included. These resins can be used alone or as a
mixture formed of two or more kinds at any ratio.
Examples of the epoxy resin include diglycidyl ether
20 compounds
of bisphenol A, bisphenol AD, bisphenol F or bisphenol
S, or their
high-molecular-weight homologs, poly (glycidyl
ether) of phenol novolac, and poly (glycidyl ether) of cresol
novolac . In
addition, halogenated derivatives of the
foregoing examples can be also used. Further, aromatic epoxy
25 resins etc. obtainable by reaction of a phenol, such as
bisphenol A, bisphenol AD, bisphenol F and bisphenol S, with
a glycidyl ether thereof may be used, and aliphatic epoxy resins
may be used as well. The epoxy resin is not particularly limited
unless it hinders the effects of the present invention. The
CA 02825701 2013-07-25
26
epoxy resin can be obtained according to a known production
method, and commercial products thereof may be also used.
The unsaturated polyester resin is not particularly limited
unless it hinders the effects of the present invention. The
unsaturated polyester resin can be produced by a known method,
and commercial products thereof may be also used. For example,
the unsaturated polyester resin can be obtained from an alcohol
component (polyhydric alcohol) , an cc, 13-unsaturated polyvalent
carboxylic acid, and an acid component (saturated polyvalent
carboxylic acid and aromatic polyvalent carboxylic acid)
according to a known production method. The vinyl ester resin
is not particularly limited unless it hinders the effects of
the present invention. The vinyl ester resin can be produced
by a known method, and commercial products thereof may be also
used.
The thermoplastic resin is not particularly limited unless
it hinders the effects of the present invention. Any of
thermoplastic styrene resins, thermoplastic polyolef in resins,
thermoplastic polyvinyl chloride resins, thermoplastic
polyurethane resins, thermoplastic polyester resins,
thermoplastic polyimide resins and other thermoplastic resins
may be used, but thermoplastic polyolef in resins are preferred.
The thermoplastic polyolef in resin is not particularly limited
and examples thereof include thermoplastic polypropylene
resins, thermoplastic polystyrene resins and thermoplastic
acrylonitrile-butadiene-styrene resins (ABS resin) . In
addition, synthetic resins, such as ethylene-propylene rubber
CA 02825701 2013-07-25
27
(EPDM), synthetic rubber based on a styrene-butadiene copolymer
(SBR), and nitrile rubber (NBR), can be also used.
The content ratio of the fiber and the resin in each of the
above-mentioned layers is not particularly limited to specific
values unless the content ratio hinders the effects of the
present invention. The content ratio varies with the kinds of
the organic fiber and the resin, and the dimension of the shaped
product. In order that the shaft may have a desired strength,
for example, a sufficient flexural stiffness, and be so
lightweight as to allow prolonged use, resistant to fracture
and excellent in safety and repairability, the content ratio
as a mass ratio is selected from the ranges of 80:20 to 60:40,
preferably 75:25 to 65:35, and more preferably 70:30 to 67:33.
When the amount of the impregnating resin is too large, an
appropriate strength cannot be easily maintained. When the
amount of the impregnating resin is too small, shaped products
cannot be obtained or, if obtained, do not have an appropriate
strength. Here, the term "appropriate strength" means a
strength for achieving the effects of the present invention.
The specific gravity of the shaft (4) varies with the kinds
of the high-strength organic fiber and the resin to be used,
the content ratio thereof and the like, but is preferably about
1.30 to 1.45, more preferably 1.32 to 1.37, and particularly
preferably 1.33 to 1.36.
The weight and strength of the cane (7) vary with the
thickness of the cane (7), the thickness of the shell (18), the
CA 02825701 2013-07-25
28
fiber-resin content ratio in each of the fiber-reinforced resin
layers (31, 32, 33) , the thickness of each of the layers, the
kind of the resin, etc. Since high-strength organic fibers have
a smaller specific gravity than that of carbon fibers, by using
less of the carbon-fiber-reinforced-resin layer (32) and more
of the high-strength-organic-fiber-resin layer (31) , a
lightweight and strong cane (7) is obtainable. In this case,
the specific gravity of the shaft (4) is not limited to specific
values, but is preferably 1.30 to 1.45. In order that the shaft
(4) may have a sufficient flexural stiffness against a force
perpendicular to the axial direction and be so lightweight as
to allow prolonged use, the specific gravity is more preferably
1.32 to 1.37, and particularly preferably 1.33 to 1.36.
In the first embodiment, the grip (1) is in an I shape, and
if needed, a connector (2) , a strap (3) , etc. may be attached
to any site of the grip (1) . Alternatively, in the present
invention, the grip (1) may be in other shapes such as a T shape
as mentioned below. The length and thickness of the grip (1)
are appropriately determined as such dimensions that the user
can firmly grasp the grip (1) .
As shown in Fig. 3, the grip (1) has a hollow-structured
grip body (19) extended upward from the upper end of the shaft
(4) . The grip body (19) may be formed integrally with the shaft
(4) by expanding one end of the shaft (4) into a predetermined
shape by, for example, blow molding, vacuum molding, etc. In
this case, since the cross-section perpendicular to the axis
of the grip body (19) is larger than that of the shaft (4) , the
CA 02825701 2013-07-25
29
grip (1) is easy for the user to firmly grasp. In addition,
since the grip (1) is hollow-structured, weight saving of the
grip (1) can be easily achieved. Further, since the same
fiber-reinforced resin materials as those of the shaft (4) are
used, a strong grip (1) can be produced at low cost.
Alternatively, in the present invention, the grip (1) may
be separately formed and fixed to the upper end of the shaft
(4) with an adhesive etc. Further, the grip (1) may be also
formed by coating the outside of any core with resin. In this
case, the core may be hollow structured. These grips (1) can
be commercial products, or produced by a known method. The
production method is not particularly limited and the
dimensions such as the length and diameter of the grip are
appropriately determined if needed.
The resin used for the grip (1) is not particularly limited
unless it hinders the effects of the present invention.
Examples thereof include polyester resins, polyamide resins
(for example, nylons such as nylon 6, 66 nylon and MC nylon),
acrylate resins, ABS resins, polyolefin resins (for example,
polypropylene resins, polyethylene resins, etc.),
polybutylene terephthalate resins and polyethylene
terephthalate resins. Fiber-reinforced resins may be also
used. Examples of the material used for the core include
silicone and nylon. In particular, it is preferable that the
grip (1) is formed of, for example, a carbon fiber-reinforced
resin and a high-strength organic fiber-reinforced resin,
because such a grip (1) is lightweight, highly strong and
CA 02825701 2013-07-25
producible at low cost.
The outer surface of the grip body (19) may be externally
exposed as it is, but preferably the outer surface of the grip
5 body (19) is in an antislip shape such as uneven patterns, or
has an antislip member (20) attached thereto as shown in Fig.
3 because such a grip (1) is easy for the user to hold. The
antislip member (20) may be a coating made of synthetic resins
such as urethane, rubber materials, etc. Alternatively, as the
10 antislip member (20) , a tape made of such materials may be
attached around the gripper. Particularly, the latter case is
preferable because such an antislip member (20) , after damaged
as a result of wear etc., can be easily replaced by a new antislip
member (20) .
As shown in Figs. 1 and 4, the ferrule (6) is fixed to the
lower end of the shaft (4) . The ferrule (6) is formed of a
high-strength organic fiber-reinforced resin and in a so-called
teardrop shape, in which the upper part is truncated conical
and the lower part is spherical. The ferrule (6) has a joint
hole (25) as a recess in the upper end, and the lower end of
the shaft (4) is fitted into the joint hole (25) and fixed
thereto.
Fixation of the ferrule (6) to the shaft (4) may be performed
using adhesives etc. so that the ferrule (6) and the shaft (4)
are inseparable. This is preferable because the ferrule (6)
does not separate from the shaft (4) during use. Alternatively,
separable fixation may be performed by press fit etc. This case
CA 02825701 2013-07-25
31
is also preferable because such a ferrule (6), after worn out,
can be easily replaced by a new one.
It is also preferable that the ferrule (6) is fitted onto
the lower end of the shaft (4) as described above, because the
lower end of this shaft (4) can be protected by the ferrule (6) .
Alternatively, in the present invention, for example, a joint
part, which may be in the shape of rod or the like, may be
protruded from the upper end of the ferrule (6), inserted into
the lower end of the shaft (4) and thereby fixed thereto.
The thickness and length of the ferrule (6) can be
appropriately determined within the range where the effects of
the present invention are not hindered. For example, the outer
diameter of the ferrule (6) is larger than that of the shaft
(4) and is such a dimension to prevent the ferrule from being
easily caught in the grating covers on the road surface, etc.
The outer surface of the ferrule (6) is smoothly curved so that
the ferrule is not stuck to steps on roads, stairs and the like,
obstacles, etc.
The high-strength organic fiber-reinforced resin which
constitutes the ferrule (6) is one obtainedbydispersing staple
fibers of a high-strength organic fiber in a synthetic resin.
When the high-strength organic fiber content is too low, the
ferrule (6) does not fully work as a sensor. Conversely, when
the content is excessively high, the fibers cannot be easily
dispersed in the synthetic resin. Therefore, the ratio of the
high-strength organic fiber in the high-strength organic
fiber-reinforced resin is preferably 10 to 60 mass%, and more
CA 02825701 2013-07-25
32
preferably 20 to 50 mass% .
Examples of the high-strength organic fiber include
ultra-high-molecular-weight-polyethylene fibers,
wholly-aromatic polyamide fibers, wholly-aromatic polyester
fibers, heterocyclic high-performance fibers and polyacetal
fibers, as is the case with the high-strength organic fiber
which constitutes the shaft (4) . These fibers may be used alone
or in a combination of two or more kinds. Specifically,
para-aramid fibers are preferably used and poly (p-phenylene
terephthalamide) fibers are particularly preferable.
The dimensions of the high-strength organic fiber dispersed
in the synthetic resin vary with the kinds of the high-strength
organic fiber and the synthetic resin, etc., but preferred is
a high-strength organic fiber with a filament fineness of about
1 .1 to 2 .3 dtex and with a fiber length of about 2 to 8 mm because
such a high-strength organic fiber can favorably disperse.
The synthetic resin used for dispersion of the high-strength
organic fiber may be a thermosetting synthetic resin etc., but
thermoplastic synthetic resins are preferable because they
enable easy formation of the ferrule (6) in a predetermined
shape. The thermoplastic synthetic resin is not particularly
limited to specific kinds, but polyamide resins such as 6 nylon,
66 nylon and MC nylon are preferable because they enable easy
dispersion of the high-strength organic fiber and easy
formation of the ferrule (6) and are excellent in wear
resistance etc.
CA 02825701 2013-07-25
33
The high-strength organic fiber-reinforced resin may
contain any fibers such as polyamide fibers, in addition to the
above-mentioned high-strength organic fiber. Further, any
additives for enhancing wear resistance, durability, light
resistance, etc., bulking agents, colorants, etc. may be
contained.
In the first embodiment, a case where the indicating layer
is covered with a wear-resistant transparent resin layer is
described. However, in the present invention, for example, a
cylindrical glass-fiber-reinforced-resin layer (33b) may be
laminated onto the outside surface of the indicating layer (34),
according to a second embodiment shown in Fig. 5.
That is to say, according to the second embodiment, the
indicating layer (34) is formed on the outside surface of a
second high-strength-organic-fiber-reinforced-resin layer
(31b), and a second glass-fiber-reinforced-resin layer (33b)
is integrally laminated onto the outside surface of the
indicating layer (34). The second
glass-fiber-reinforced-resin layer (33b) is transparent, and
thus the indicating layer (34) can be clearly seen from the
outside. Further, the second glass-fiber-reinforced-resin
layer (33b) is excellent in wear resistance and water resistance,
and thus prevents the indicating layer (34) from getting worn
or getting wet and detached. Unlike the first embodiment, no
wear-resistant transparent resin layer is needed and thus the
corresponding cost can be cut. Other constitutions are the same
CA 02825701 2013-07-25
34
as those of the first embodiment and function similarly.
Therefore, descriptions therefor will be omitted.
In the first embodiment, a straight cane is described.
However, the cane of the present invention may be a folding cane,
for example, as shown in Figs. 6 and 7.
According to a third embodiment, as shown in Fig. 6 (a),
a cane (7) has a shaft (4), a grip (1) provided at the upper
end of the shaft (4), and a ferrule (6) fixedly attached to the
lower end of the shaft (4), as is the case with the first
embodiment. However, unlike the first embodiment, the shaft
(4) consists of a plurality of mutually connectable and
separable shaft parts (14), for example, five shaft parts (14),
and a cylindrical joint cover (5) is provided to cover each
junction where two shaft parts (14) are connected to each other.
The grip (1) is extended from the upper end of the top shaft
part (14) and formed integrally therewith.
As is the case with the shaft (4) of the first embodiment,
the shaft part (14) is in the shape of a hollow cylinder of which
the cross-section perpendicular to the axis is in a circular
shape. In addition, as shown in Fig. 6 (b), the shaft part (14)
comprises a carbon-fiber-reinforced-resin layer (32) and a
high-strength-organic-fiber-reinforced-resin layer (31)
integrally formed on each of the inside and outside surfaces
of the carbon-fiber-reinforced-resin layer (32). Further, on
each of the outer and inner
high-strength-organic-fiber-reinforced-resin layers (31), a
glass-fiber-reinforced-resin layer (33) is provided. On the
CA 02825701 2013-07-25
outside surface of the second glass-fiber-reinforced-resin
layer (33b) , a white reflective tape (15) and a red-colored tape
(16) are attached, and the outside surface of each tape is
covered with a wear-resistant transparent resin layer (35) .
5
As shown in Figs. 8 and 9, in the shaft parts (14) adjacent
to each other, an inner pipe (9) as a smaller-diameter part is
fixedly secured to a first connecting end (21) of one shaft part
(14) , and a rubber cord (8) connecting the shaft parts (14) is
10 inserted through the inner pipe (9) . The protruding length of
the inner pipe (9) protruding outward from the first connecting
end (21) is not limited to specific values as long as the length
is enough for firm connection of the shaft parts (14) . For
example, the length is about 30 to 50 mm.
15 The material and thickness of the rubber cord (8) are not
particularly limited as long as the rubber cord (8) is so elastic
and stretchy as to allow easy separation and connection of the
shaft parts (14) , and known rubber cords can be used.
20 The inner
pipe (9) has an outer diameter approximately equal
to the inner diameter of the shaft part (14) , and can be inserted
into and removed from a second connecting end (22) of the
opposite shaft part (14) . According to this embodiment, the
inner pipe (9) is formed separately from the shaft part (14)
25 and one end thereof is fixed into the first connecting end (21)
by press fit, known adhesives, etc. Alternatively, in the
present invention, the smaller-diameter part may be formed
integrally with the connecting end of the shaft part (14) . The
material of the inner pipe (9) is not limited to specific kinds,
CA 02825701 2013-07-25
36
but the inner pipe (9) preferably comprises a
high-strength-organic-fiber-reinforced-resin layer and a
glass-fiber-reinforced-resin layer as used for the shaft part
(14) , and more preferably comprises only a
high-strength-organic-fiber-reinforced-resin layer composed
of a para-aramid fiber and the like. Unlike the shaft part (14) ,
it is preferable that the inner pipe (9) does not comprise any
carbon-fiber-reinforced-resin layer.
One end of the joint cover (5) is fitted onto the first
connecting end (21) and fixed thereto. The joint cover (5) is
not limited to specific shapes as long as it is cylindrical and
can connect the shaft parts (14) . However, it is preferable
that the outer surface of the joint cover (5) is so smooth as
not to be caught in other objects. For example, the joint cover
(5) is in a cylindrical shape with the diameter slightly
decreasing toward both ends, and has a ring-shaped stopper (23)
inside centered on the length of the joint cover. The rubber
cord (8) penetrates the stopper (23) . The first connecting end
(21) is inserted from one end of the joint cover (5) until it
abuts against the stopper (23) , and is firmly fixed by press
fit, known adhesives, etc.
The other end of the joint cover (5) faces and is open for
the second connecting end (22) , and has an inlet (24) therein.
By inserting the second connecting end (22) into the inlet (24) ,
the shaft parts (14) are connected to each other, and by removing
the second connecting end (22) from the inlet (24) , the shaft
parts (14) are separated from each other.
CA 02825701 2013-07-25
37
The inlet (24) has a tapered part (10) with the diameter
gradually decreasing inward from the outer end, and a straight
part (11) having a predetermined inner diameter and extended
further inward from the inner end of the tapered part (10) to
the stopper (23). The inner diameter of the straight part (11)
is determined as such a dimension that the inner surface of the
straight part (11) can tightly press the outer surface of the
second connecting end (22) without any backlash.
The length of the joint cover (5) is not limited to specific
values and can be appropriately determined within the range
where the effects of the present invention are not hindered.
The length of the tapered part (10) is preferably larger than
that of the straight part (11). In this case, the axial
alignment of the shaft parts (14) to be connected is easy and
the second connecting end (22) can be smoothly guided.
Specifically, the tapered part-straight part ratio is
preferably about 5 to 2 : 1 . The length of the straight part (11)
is not limited to specific values as long as the length neither
allows any backlash in the junction nor hinders any effect of
the present invention. However, because connection and
separation cannot be easily performed in the case of an
excessively long straight part, the length of the straight part
(11) is preferably about 20 to 80% of the outer diameter of the
shaft (4) in general.
The joint cover (5) is produced from, for example,
polyamides such as nylon 6. As long as the joint cover (5) can
CA 02825701 2013-07-25
38
firmly hold the junction and effects of the present invention
are not hindered, the material thereof is not limited to
specific kinds. Specifically, for example, thermosetting
resins such as epoxy resins, unsaturated polyester resins and
vinyl ester resins may be used. In addition, thermoplastic
resins such as polyester resins, polyamide resins (for example,
nylons such as nylon 6, 66 nylon and MC nylon) , acrylate resins,
ABS resins, polyolef in resins (for example, polypropylene
resins, polyethylene resins, etc. ) ,
polybutylene
terephthalate resins and polyethylene terephthalate resins may
be used. Further, materials having rubber elasticity, such as
synthetic rubbers and elastomers, may be used. The joint cover
(5) can be produced by a known method. In the production, known
additives, pigments, etc. may be appropriately added if needed,
and fiber-reinforced resins may be used. Also, coloring etc.
may be performed after the production.
After the second connecting end (22) is inserted into the
inlet (24) of the joint cover (5) , the second connecting end
(22) is smoothly guided by the tapered part (10) , passes along
the straight part (11) and then abuts against the stopper (23) .
In this way, connection as shown in Fig. 9 is achieved. In this
connection, the outer surface of the second connecting end (22)
is tightly pressed by the inner surface of the straight part
(11) , and thus no backlash is allowed.
The above constitution prevents stress from concentrating
on specific parts of the cane (7) , such as the above-described
connecting ends, and enhances the mechanical strength of the
CA 02825701 2013-07-25
39
junctions, on which stress tends to concentrate, by sufficient
reinforcement with the external joint covers (5). Therefore,
the cane (7) has less risk of breaking due to such a stress
concentration and less risk of the user's falling, can be safely
used, and thus is preferable. Further, since there is no
backlash, the connecting ends are prevented from early wear-out
due to mutual friction at the time of connection/separation,
and therefore the durability of the cane (7) is increased.
Further, the axis of the cane (7) does not bend during use, and
thus the user can use the cane with a sense of security. For
the shaft parts (14), special structures such as screw clamps
in connecting ends are not needed since only insertion/removal
of the connecting ends and the smaller-diameter part (9)
provided thereon are needed at the time of
connection/separation. Therefore, the shaft parts (14) have
a simple structure, can be produced at low cost, allow easy
connection/separation, and thus are preferable.
In the third embodiment, one end of the joint cover (5) is
fixed to the first connecting end (21), and the second
connecting end (22) can be inserted into and removed from the
other end of the joint cover (5) . Alternatively, in the present
invention, it is possible that one end of the joint cover (5)
is fixed to the second connecting end (22) of the shaft part
(14) not provided with a smaller-diameter part, and that the
first connecting end (21) of the opposite shaft part (14)
provided with a smaller-diameter part can be inserted into and
removed from the other end of the joint cover (5).
CA 02825701 2013-07-25
According to the third embodiment, the ferrule (6) is a
standard type, that is, in a cylindrical shape with a smoothly
curved surface in the lower part. The upper part has a curved
surface that has a diameter gradually decreasing toward the
5 upper end and is continued to the outer surface of the shaft
(4). As is the case with the first embodiment, the ferrule (6)
is formed of a high-strength organic fiber-reinforced resin and
has a joint hole (25) as a recess in the upper end, and the lower
end of the shaft (4) is fitted into the joint hole (25) and fixed
10 thereto. Other constitutions, such as the grip (1), are the
same as those of the first embodiment and function similarly.
Therefore, descriptions therefor will be omitted.
In the above embodiments, canes (7) with a so-called
15 I-shaped grip (1) are described. However, the cane of the
present invention may have a grip (1) of other shapes such as
modified example 1 shown in Fig. 10. For example, Fig. 10 (a)
shows a cane (7) provided with a so-called T-shaped grip (1),
Fig. 10 (b) shows a cane (7) provided with a so-called L-shaped
20 grip (1), and in both cases, the grip (1) is extended from the
upper end of the shaft (4).
In the first embodiment, a teardrop type ferrule is used,
and in the third embodiment, a standard type ferrule is used.
25 However, the ferrule (6) used for the present invention is not
limited to specific shapes unless the use as a cane is hindered.
For example, the above standard type ferrule may be used in a
straight cane as illustrated in the first embodiment, and the
above teardrop type ferrule may be used in a folding cane as
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illustrated in the third embodiment. In addition, for example,
like modified example 2 shown in Fig. 11, the above standard
type ferrule can be a standard type ferrule (6) which has a
shoulder and has a smaller diameter in the upper part to reduce
the risk of being caught in other objects.
EXAMPLES
Hereinafter, the present invention will be illustrated in
more detail by examples and comparative examples, but is not
limited to the examples below.
<Example 1>
As a high-strength organic fiber, a poly (p-phenylene
terephthalamide) fiber, KEVLAR K-29 1670 dtx (manufactured by
DU PONT-TORAY CO., LTD.) was used. From this organic fiber,
a unidirectional (UD) sheet with a fiber areal weight of 73 g/m2
was prepared, and the sheet was impregnated with an epoxy resin
by a hot melt method in such a manner that the fiber-resin content
ratio might be 67:33. In this way, a high-strength organic
fiber prepreg with a fiber areal weight of 110 g/m2 was obtained.
As a carbon fiber prepreg, TORAYCA (registered trademark)
prepregs (type: 9052S-17 and 3252S-05, manufactured by Toray
Industries, Inc.) were used. Each of these prepregs is a carbon
fiber prepreg with a fiber areal weight of 330 g/m2 and is
produced by impregnating a UD sheet with a fiber areal weight
of 220 g/m2 with an epoxy resin in such a manner that the
fiber-resin content ratio may be 67:33.
As a glass fiber, a glass fabric, WPA-240D (manufactured
by Nitto Boseki Co., Ltd. ) , which is a UD sheet with a fiber
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areal weight of 100 g/m2, was used, and the glass fabric was
impregnated with an epoxy resin by a hot melt method in such
a manner that the fiber-resin content ratio might be 67 :33 . In
this way, a glass fiber prepreg with a fiber areal weight of
150 g/m2 was obtained.
Next, one layer of the glass fiber prepreg as the innermost
layer, three layers of the high-strength organic fiber prepreg,
one layer of the carbon fiber prepreg, two layers of the
high-strength organic fiber prepreg, and one layer of the glass
fiber prepreg were laminated in this order, integrated and cured
with heat. Around the surface of the cured product, a
reflective tape was attached and a 0 . 06-mm-thick HIMILAN film
(trade name, manufactured by DU PONT-MITSUI POLYCHEMICALS) as
a wear-resistant transparent resin film was laminated to cover
the tape. In this way, a cylindrical body of Example 1 was
obtained.
<Comparative Example 1>
According to the procedures of Example 1 except using the
above-mentioned carbon fiber prepreg instead of the
high-strength organic fiber prepreg and the glass fiber prepreg
of Example 1, a cylindrical body of Comparative Example 1 was
obtained.
<Comparative Example 2>
According to the procedures of Example 1 except using the
above-mentioned high-strength organic fiber prepreg instead of
the carbon fiber prepreg and the glass fiber prepreg of Example
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1, a cylindrical body of Comparative Example 2 was obtained.
Regarding each of the obtained cylindrical bodies, the outer
diameter was 12 mm and the cross-sectional area ratio of the
hollow and the shell was 67:33.
Next, these cylindrical bodies were measured for stiffness
(flexural property), impact resistance, safety and on-site
repairability, and the respective characteristic values were
determined. The measurement was performed according to the
following methods.
<Stiffness (Flexural property)>
Each cylindrical body in the above-mentioned Example and
Comparative Examples was supported by two fulcrum points the
distance between which was 780 mm, and a 3-kg weight was hooked
on the cylindrical body in the middle between the fulcrum points
and left to stand for 10 seconds. The degree (mm) that the
cylindrical body bent in response to the weight was measured.
<Impact resistance>
A 30-cm piece was cut from each cylindrical body in Example
and Comparative Examples and used as a sample. According to
the three point flexural test specified in JIS K 7055:1995
(Testing method for flexural properties of glass
fiber-reinforced plastics), using a Drop Weight Impact Tester
(trade name: Dynatup (registered trademark) 9210, manufactured
by Instron), the sample was fixed by two fulcrum points the
distance between which was 105 mm, and given an impact force
of 110J by use of an indenter 22 mm in diameter. The fracture
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condition, the absorbed energy, etc. of each sample were
determined.
The evaluation criteria for the fracture condition are as
follows.
A: Not fractured
B: Partially fractured
C: Easily and completely fractured
<Safety>
After the impact resistance test, the safety was evaluated
based on the presence or absence of spiky fibers projected from
the impact site of each cylindrical body.
The evaluation criteria for the safety are as follows.
A: There were no spiky fibers projected and sufficient safety
was confirmed.
B: There were a few spiky fibers projected.
C: There were spiky fibers projected and they might get stuck
in the hand.
<On-site repairability>
After the impact resistance test, the fractured or damaged
site was repaired by use of an emergency repair kit for domestic
white canes ( trade name: YATSUHASHI -KUN; product number: 3 9 03 2 )
distributed by the Tool Sales Division of Japan Braille Library,
and the on-site repairability was evaluated based on whether
the repaired cylindrical body was usable as a cane shaft. This
emergency repair kit (26) contains one pair of semicylindrical
supporting plates (13) , for example, as shown in Fig. 1 2 .
Repair of a fractured shaft (4) by use of this emergency repair
CA 02825701 2013-07-25
kit (26) is performed as follows. The release tape of a
double-sided tape (12) stuck on the back of each supporting
plate (13) is stripped off, the two supporting plates (13) are
attached onto the fractured shaft in such a manner that the
5 fracture site of the shaft (4) is centered on the length of each
supporting plate and is sandwiched in between the supporting
plates, and accessory reflective tapes (15) are attached over
the upper and lower ends of the supporting plates (13) to firmly
fix the supporting plates to the cylindrical body. In this way,
10 the fractured shaft comes into the state as shown in Fig. 13.
The evaluation criteria of the on-site repairability are
as follows.
A: After impact was given, simple repair on site reproduced a
usable cane.
15 C: After impact was given, simple repair on site was not
applicable and did not reproduce a usable cane.
The measurement results of the above-mentioned
characteristic values are as shown in Measurement Result
20 Comparison Table 1 in Fig. 14.
As is clear from the measurement results, Comparative
Example 1 formed of only a carbon-fiber-reinforced-resin layer
had a high stiffness, but was not enough in impact resistance
against a force in a direction perpendicular to the axis of the
25 cylindrical body. Also, at the time of impact, Comparative
Example 1 fractured with spiky fibers projected, and thus was
not excellent in safety or on-site repairability. Comparative
Example 2 formed of only a
high-strength-organic-fiber-reinforced-resin layer had an
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excellent impact resistance and did not fracture at the time
of impact, and thus was excellent in safety and on-site
repairability. However, the flexural degree was high when the
load was applied in a direction perpendicular to the axial
direction, and thus the stiffness was low.
By contrast, Example 1 of the present invention was more
excellent in stiffness than Comparative Example 2. In addition,
Example 1 bent only slightly at the time of impact and thus was
excellent in impact resistance against a force in a direction
perpendicular to the axis of the cylindrical body. Moreover,
Example 1 did not allow spiky fibers to be projected from the
impact site and thus was excellent in safety, and did not
fracture and thus was also excellent in on-site repairability.
Example 1 of the present invention, which comprises a
glass-fiber-reinforced-resin layer inside, is excellent in
wear resistance of the inner surface unlike Comparative Example
2, which comprises only layers made of a high-strength organic
fiber prepreg. For example, in the case of a folding cane having
a rubber cord arranged inside its shaft, the shaft ends are
prevented from early wear-out due to the friction against the
rubber cord.
Since Example 1 had a wear-resistant transparent resin film
laminated to cover a reflective tape attached around the outer
surface of the cylindrical body, it was expected that Example
1 would be much more excellent in wear resistance of the outer
surface and thus could be more favorably prevented from wear-out
of the reflective tape, as compared with conventional products
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without the film. For confirmation of these effects, the wear
resistance of the outer surface was measured according to the
following method.
<Wear resistance of outer surface>
An abrasive cloth sheet 25 mm in width and 300 mm in length
(grain size: 4*240, manufactured by Noritake Coated Abrasive Co.,
Ltd.) was used. As shown in Fig. 15, the shaft (4) was kept
in a horizontal position, the abrasive cloth sheet (36) was
horizontally and vertically placed in the 90-degree direction
to the axis of the shaft (4) in such a manner that the sheet
was in contact with a quadrant part ( 90 -degree part) of the shaft
(4) surrounded by the upper horizontal plane and the vertical
plane. Under the condition that a 330-g weight (37) was hung
on the lower end of the upright portion of the abrasive cloth
sheet (36), the abrasive cloth sheet (36) was moved 200 mm
against the shaft at the speed of 2 seconds per stroke to abrade
the surface of the shaft (4).
As a result of the measurement, in the case where the
reflective tape was externally exposed without the
wear-resistant transparent resin film, the superficial
reflective tape was worn out in five strokes and the
glass-fiber-reinforced-resin layer under the tape was exposed.
By contrast, in the case of Example 1 of the present invention,
which had a wear-resistant transparent resin film laminated
onto the outside surface of the reflective tape, the reflective
tape was not worn out at all even after 100 strokes.
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Next, a teardrop type ferrule (6) was attached to the
cylindrical body of Example 1 and the resulting product was
regarded as Example 2. For examination of the usage
characteristics of this ferrule (6) , the information
transmission performance and the manipulability were tested by
use of the actual road surfaces shown in Fig. 16, and the
antisticking property (smooth mobility over the uneven surface)
was tested by use of antislip parts of stairs, gaps on the road
surface, etc. For the test, three kinds of road surfaces were
used, that is, an asphalt pavement surface shown in Fig. 16 (a) ,
a concrete pavement surface arranged with gravels shown in Fig.
16 (b) , and a concrete pavement surface with a tiled pattern
shown in Fig. 16 (c) .
From a high- strength-
organic- fiber- reinforced- resin
material, the above-mentioned ferrule (6) was formed in a
teardrop shape 26.1 mm in maximum outer diameter and 40.4 mm
in length. Then, the lower end of the shaft (4) 12.5 mm in outer
diameter was inserted into a joint hole (25) 13 mm in inner
diameter formed in the upper end of this ferrule (6) and fixed
thereto with an adhesive. The
high- strength-organic- fiber- reinforced-resin material was
one in which
staple fibers of a poly (p-phenylene
terephthalamide) fiber were dispersed in a polyamide resin
(Nylon 6) , and was obtained by cutting 1.7-dtex filaments of
the poly (p-phenylene terephthalamide) fiber into 6-mm pieces,
and then dispersing the pieces in the polyamide resin. The
high- strength-organic- f iber- reinforced- res in material
contained 70 mass% of the polyamide resin and 30 mass% of the
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poly (p-phenylene terephthalamide) fiber.
<Information transmission performance>
It was tested whether the cane is capable of transmitting
information on road surface conditions such as unevenness and
smoothness to the user. In the case where the user examining
the road surface could detect the differences of the road
surfaces, the subject cane was evaluated as "good," and in the
case where the user could not detect such differences, the
subject cane was evaluated as "poor."
<Manipulability>
The burden given to the hand and wrist when the user swung
around the cane or poked the road surface etc. with the cane
was measured. In addition, the sound level was measured when
the ferrule touched the road surface. In the case where the
subject cane in use gave less burden to the hand and wrist and
did not make a loud sound, the subject cane was evaluated as
"good," and in the case where the burden was heavy and the sound
was loud, the subject cane was evaluated as "poor."
<Ant i st icking property>
It was tested whether or not the subject cane would be stuck
to or caught in antislip parts of stairs, gaps on the road surface,
etc. In the case where the subject cane was not stuck or caught,
the subject cane was evaluated as "good," and in the case where
the subject cane was stuck or caught, the subject cane was
evaluated as "poor."
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Regarding the above-mentioned usage characteristics, the
measurement results in comparison with conventional ferrules
for canes are shown in Measurement Result Comparison Table 2
in Fig. 6.
5 Each
conventional ferrule used for the comparison was made
of a polyamide resin (PA6) , a standard type was regarded as
Comparative Example 3, a teardrop type was regarded as
Comparative Example 4, and a palm tip type was regarded as
Comparative Example 5. The palm tip type as Comparative Example
10 5 was one
having an elastic member between the shaft and the
grounding part of the ferrule, as described in, for example,
the WO 07/058180 pamphlet. Specifically, the one having an
elastic member made of chloroprene rubber between the shaft and
the grounding part made of a polyamide resin was used.
As is clear from the results of the above-mentioned
measurement, Comparative Examples 3 to 5 did not enable easy
recognition of the kind of the road surface, and thus were poor
in information transmission performance. By contrast, Example
2 of the present invention enabled easy recognition of the three
kinds of road surfaces, and thus was extremely excellent in
information transmission performance.
Specifically, while using any of Comparative Examples 3 to
5, the user had a feel that the ferrule stuck to the road surface
as if writing letters with a crayon, and thus could not easily
detect the kind of the road surface. By contrast, while using
Example 2 of the present invention, the user had a feel that
the ferrule lightly touched the road surface and slightly
bounced back therefrom as if writing letters with a pencil, and
,
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the feel clearly varied with the kind of the road surface.
Further, Example 2 of the present invention was more
excellent in manipulability than not only Comparative Example
4 but also Comparative Examples 3 and 5.
Specifically, while manipulating Comparative Example 4,
the user was given a heavy burden to the hand and wrist, and
thus the manipulability was poor. Regarding Comparative
Examples 3 and 5, the burden was lighter than that of Comparative
Example 4, and thus the manipulability was favorable. By
contrast, regarding Example 2 of the present invention, the
ferrule favorably reacted against the road surface to be
examined, and thus the user was less required to excessively
swing around the cane or poke about therewith, and was given
further less burden to the hand and wrist than that in
Comparative Examples 3 and 5. In addition, the sound generated
when the user hit the road surface with the cane was not so loud,
and thus the manipulability was extremely favorable.
Next, the wear resistance of the ferrule (6) was measured.
The test product was made of the
high-strength-organic-fiber-reinforced-resin material used
for the standard type ferrule adopted in the third embodiment
and was regarded as Example 3. This
high-strength-organic-fiber-reinforced-resin material
consists of a polyamide resin (66 nylon) reinforced with staple
fibers of a poly(p-phenylene terephthalamide) fiber, which is
a high-strength organic fiber. The content ratio of the
high-strength organic fiber to the fiber-reinforced resin is
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30 mass%. As the comparative test products, a molded product
made of a polypropylene resin (PP) alone and a molded product
made of a polyamide resin (Nylon 6) alone were used and regarded
as Comparative Examples 6 and 7, respectively.
The test method was in accordance with method A specified
in JIS K7218:1986 (Testing methods for sliding wear resistance
of plastics) and the following conditions were adopted.
- Test piece: ring (hollow cylindrical shape)
- Opponent material: SUS304 ring (hollow cylindrical shape)
The surface roughness was adjusted by finishing with #1000
abrasive paper (0.1 mRa>).
- Measurement item: wear mass
- Measurement conditions
Sliding speed: 500 mm/second
Friction area: 2 cm2
Test load: 100 N
Test time: 100 minutes (3 km)
Number of measurement: n = 1
- Laboratory environment: temperature: 23 2 C, humidity:
50 10%RH
-Measuring device: rotary tribometer for kinetic friction and
wear tests, IIIT-2000-5000N model (manufactured by
Takachihoseiki Co., LTD.)
The test results are as shown in Measurement Result
Comparison Table 3 in Fig. 18.
As is clear from the test results, Comparative Example 6
formed of polypropylene resin was worn out at the early stage,
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and Comparative Example 7 formed of polyamide resin showed a
large wear mass and was frictionally heated, resulting in resin
melting in the middle of the test. By contrast, since the
high-strength organic fiber-reinforced resin was used in
Example 3 of the present invention, constant wear was maintained
till the end of the test and even the constant wear mass was
slight. Accordingly, it was confirmed that the ferrule of the
present invention formed of a high-strength organic
fiber-reinforced resin is excellent in wear resistance.
The canes and the cylindrical bodies used therefor described
in the above-mentioned embodiments are illustrated in order to
embody the technical ideas of the present invention. Therefore,
the shape, the dimension, the number of layers, etc. of each
component are not limited to those specified in these
embodiments, and various modifications can be made within the
scope of the claims.
For example, the shaft and the grip are integrally formed
in the first embodiment, but in the present invention, they may
be separately formed and fixed to each other.
Regarding the folding cane of the third embodiment, a case
where joint covers are provided at all the junctions of shaft
parts is described. However, in the present invention, the
joint cover may be omitted at any junction. For example, the
joint cover may be provided only at the lowermost junction,
which is prone to break, not at the other junctions.
In each of the above-mentioned embodiments, the indicating
layers are a reflective tape and a colored tape. However, in
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the present invention, other kinds of indicating layers maybe
used and these indicating layers may be omitted.
In the above-mentioned embodiments, a poly(p-phenylene
terephthalamide) fiber is used as a high-strength organic fiber,
but it will be understood that other kinds of high-strength
organic fibers may be also used in the present invention.
INDUSTRIAL APPLICABILITY
The cane of the present invention is useful as a cane for
sports such as mountain climbing and skiing or for ordinary
walking, as well as a white cane for the visually disabled.
Further, the cane of the present invention gives less physical
burden to the user, is greatly beneficial in particular to the
elderly, juniors and the visually disabled, and is also helpful
to facilitate self-support, to increase social participation
of people in need of nursing care, and to improve labor
productivity.
REFERENCE SIGNS LIST
1 ... Grip
4 ... Shaft
5 ... Joint cover
6 ... Ferrule
7 ... Cane
9 ... Smaller-diameter part (inner pipe)
14 ... Shaft part
17 ... Hollow
18 ... Shell
19 ... Grip body
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20 ... Antislip member
21 ... First connecting end
22 ... Second connecting end
31 ... High-strength-organic-fiber-reinforced-resin layer
5 31a ... First high-strength-organic-fiber-reinforced-resin
layer
31b ... Second high-strength-organic-fiber-reinforced-resin
layer
32 ... Carbon-fiber-reinforced-resin layer
10 33 ... Glass-fiber-reinforced-resin layer
33a ... First glass-fiber-reinforced-resin layer
33b ... Second glass-fiber-reinforced-resin layer
34 ... Indicating layer
35 ... Wear-resistant transparent resin layer
