Note: Descriptions are shown in the official language in which they were submitted.
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WO 99/05380 PCTIIQt98/00217
STRUCTURAL MEMBER HAVING A METAL SHELL
REINFORCED BY A REINFORCING PLATE
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a structural member
with an elongated hollow thin metal shell filled with a
filler; and, more particularly, to a novel structural member
provided with a.reinforcing plate attached to an inner wall
of the elongated hollow thin metal shell to improve the
tensile strength thereof.
BACKGROUND ART
In general, a structural member such as .a pillar,
column, post, pole, beam and the like is made of lumber,
concrete, metal or their composites according to its
intended use.
In particular, a structural member made of concrete' has
been widely used in the construction field because of its
high compressive strength and economy. Also, it has a
further advantage that it can be easily made in various
shapes by designing diverse molds. However, such concrete
columns and posts are not normally suitable for use in
decorative articles due to their rough surface
characteristics and non-aesthetic appearance. Accordingly,
additional finishing elements made of lumber and/or metal
plates are required to refurbish the crude surfaces of the
concrete members in order to employ them for sophisticated
purposes.
Consequently, hollow metal structural members made of,
e.g., aluminum, aluminum alloys, stainless steel, zinc
plated steel, special steel, copper or copper alloys are
increasingly employed in various structural members such as
supporting columns, connecting bars, ornamental poles and
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the like because of their appealing appearance, high
corrosive resistance and easy workability. In such hollow
metal members, a relatively greater thickness is required to
withstand a given load, thereby entailing a high
material/manufacturing cost.
Therefore, there have been attempts made to reduce the
thickness of such a hollow metal structure by way of forming
a section of the structure in a bent or inwardly grooved
shape, to thereby increase the bending strength and the
moment of inertia of the metal structure. However, the
manufacturing cost of such metal member still remains
relatively high because the formation of a particular shape
in the metal member adds further manufacturing steps. In
addition, reducing the thickness of the metal member in an
effort to reduce the cost can backfire as it makes the
structure vulnerable to an external impact.
Accordingly, various structural members have been
developed with the specific purpose of improving their
tensile and compressive strength.
There is disclosed in U.S. Patent Nos. 5,263,297 and
5,457,929 issued to the present applicant, a structural
member adapted to be used in combination with a base, the
structural member comprising an elongated hollow thin metal
shell, a reinforcing end piece engaged in an end portion of
the shell, the reinforcing end piece having a through-hole,
and a filler moulded into the hollow thin shell and the
through-hole of the reinforcing end piece. The reinforcing
end pieces disclosed in the above patents may be embedded in
the concrete filler, thereby preventing both ends of the
shell from being deformed in the process of injecting
concrete mortar into the shell and preventing both end
portions of the structural member from rupturing or breaking
during the transportation or construction thereof.
One of the major shortcomings of the prior structural
members is that they are essentially capable of supporting
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small to medium loads only. In other words, in situations
where they are required to support large loads, especially
large tensile loads such as bridge balustrades, building,
erection and the like, they cannot be used.
DISCLOSURE OF THE INVENTION
It is, therefore, a primary object of the present
invention to provide a structural member with a thin metal
shell capable of supporting even a large tensile load.
The above and other objects of the present invention
are accomplished by providing a structural member
comprising:
an elongated hollow case including at least two thin
metal shells, each side end of the metal shells having an
inwardly bent flange along its entire length and the bent
flanges facing each other to form the elongated hollow case;
a reinforcing plate attached to an inner surface of
each of the metal shells; and
a filler moulded into the hollow case.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other objects, features and advantages of
the present invention will become apparent from the
following detailed description of preferred embodiments
taken in conjunction with the accompanying drawings, in
which:
Fig. 1 shows an exploded perspective view, with a
filler of concrete removed for the sake of clarity, of a
structural member having a reinforcing plate in accordance
with a preferred embodiment of the present invention;
Fig. 2 exemplifies a perspective view for explaining
stresses applied to the structural member of Fig. 1;
Figs. 3A to 3E are perspective views for illustrating
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various variations of the reinforcing plate and for showing
directions of the applied stresses;
Fig. 4 presents a sectional view taken along I-I line
in Fig. 3D;
Fig. 5 demonstrates a perspective view of the
reinforcing plate with cut-out portions only;
Fig. 6 indicates an exploded perspective view, with a
filler of concrete removed for the sake of clarity, of a
structural member incorporating therein a connecting means
with a reinforcing plate and a thin metal shell in
accordance with a second preferred embodiment of the present
invention;
Fig. 7 provides a sectional view showing how the
structural member shown in Fig. 6 is assembled;
Fig. 8 depicts a view similar to that of Fig. 6 with a
connecting means slightly different from that shown in Fig.
6;
Fig. 9 represents a sectional view showing how the
structural member shown in Fig. 8 is assembled;
Fig. 10 offers an exploded perspective view of another
reinforcing end piece of Fig. 1;
Fig. 11 describes a sectional view showing the details
of the structural member of Fig. 10;
Fig. 12 illustrates a partially cut out perspective
view of the structural member, with concrete moulded into
the hollow shell of Fig. 10, employing the reinforcing end
piece of Fig. 10;
Fig. 13 sets forth a sectional view taken along line
II-II of Fig. 12;
Fig. 14 displays an exploded perspective view showing
a further embodiment of the reinforcing end piece of Fig. 1;
Fig. 15 gives an exploded perspective view showing a
still another embodiment of the reinforcing end piece of
Fig. 1; and
Fig. 16 employs an exploded perspective, with a filler
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of concrete removed for the sake of clarity, of a circular
structural member having a circular reinforcing plate in
accordance with a third preferred embodiment of the present
invention.
MODES OF CARRYING OUT THE INVENTION
Referring to Fig. 1, there is shown a structural member
100 in accordance with a preferred embodiment of the present
invention. As shown, the structural member 100 comprises an
elongated hollow case 110 having a pair of thin shells 112,
a pair of reinforcing end pieces 120 inserted into both ends
of the case 110, and a pair of reinforcing plates 130
attached to an inner wall of each of the elongated shells
112, respectively. The case 110 is filled with a filler 140
(Fig. 2), e.g., concrete mortar.
In the structural member in accordance with an
embodiment of the invention, the thin shell 112 may be made
of metal such as stainless steel, aluminum, copper or their
respective alloys . Each side end of the metal shells 112
along its entire length is provided with an inwardly bent
flange 114 to allow the hollow case 110 to be formed by
facing the flanges 114. As a result of the flanges facing
each other in forming the case, ribs are formed in the case
along its entire length, the ribs further increasing the
contact areas between the filler 140 and the case 110. The
ribs will function as the anchors for the filler 140.
The reinforcing end pieces 120 are provided with a
through-hole 122 through which the filler 140 is injected
into the case 110, a stepped portion 124 formed around an
upper portion thereof for preventing the reinforcing end
pieces 120 from being excessively inserted into the case 110
and a pair of slit portions 126 formed at both sides
thereof, respectively, to thereby allow the ribs of the case
110 to be slid therealong, allowing the reinforcing end
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pieces 120 to be tightly engaged with the case 110.
The reinforcing plate 130 is made of a metal, layers of
fibrous material selected from the group consisting of
carbon fiber, aramid fiber and glass fiber, or a combination
thereof, i.e., a combination of the metal and fiber layers.
The reinforcing plate 130 is attached to the inner wall of
the metal shell 112 by means of an adhesive such as epoxy
resin, soldering or spot welding to improve the tensile
strength of the structural member 100. Further, the
reinforcing plate 130 may be further provided with a pair of
projections 132 formed by inwardly bending each side end
thereof along its entire length in order to increase the
contact area between the reinforcing plate 130 and the
filler 140. The projections 132 function as the anchor for
the filler 140.
When a load W is applied, as shown in Fig. 2, on the
inventive structural member, the structural member is
subjected to three types of stresses; a compressive stress
on upper portion of the structural member as indicated by
arrows A, a tensile stress on a lower portion thereof as
indicated by arrows B and a shear stress on a side portion
thereof as indicated by arrows C. The strength of the
structural member is associated with its ability to
withstand, i.e., absorb or relieve, the stresses applied
thereon.
The reinforcing plate 130 attached on the inner walls
of the case 110 absorbs or relieves the tensile stress built
in the structural member as shown in Fig. 3A. The projection
132 on each end of the reinforcing plate 130 along its
length enhances the tensile and the shear strengths of the
structural member 100 by functioning as the additional
anchoring means for the filler as shown in Fig. 3B.
Unlike the reinforcing plate 130 of Fig. 3B provided
with the projections 132 on both side ends thereof along
their entire length, the reinforcing plate 130 may be
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provided with at least one cut-out portion 131 and an
appropriate number of projections 133 formed on a side of
the cut-out portions 131 of the reinforcing plate 130 as
shown in Figs. 3C to 3E.
As best shown in Fig. 4, when the reinforcing plate 130
with cut-out portions 131 and projections 133 is attached to
the metal shell 112 by means of an adhesive 138 such as
epoxy resin, the cut-out portions 131 get filled with the
adhesive 138, the adhesive filling the cut-out portions 131
functioning as an additional means for absorbing the tensile
stress and the shear stress. The number and the location of
cut-out portions 131 and the projections 133 are determined
by the tensile strength desired.
In addition, the reinforcing plate 130 may be simply
provided with a plurality of cut-out portions 134 having any
particular shape, as shown in Fig. 5, the adhesive filling
the cut-out portions 134 serving to absorb the tensile
stress, thereby increasing the tensile strength of the
structural member 100.
Referring now to Figs. 6 and 7, there is shown a
structural member capable of connecting other objects
thereto in accordance with a second preferred embodiment of
the present invention. As shown, the structural member 200
includes an elongated hollow case 210 including at least two
thin metal shells 212, each of the metal shells 212 having
an aperture 216, and a reinforcing plate 230 attached to an
inner surface of each of the metal shells 212 and having an
aperture 234 corresponding to the aperture 216 of the each
of the thin metal shells 212. Other structural members(not
shown) can be connected to the inventive structural member
200 by way of an appropriate connection means 250 through
the apertures 216 and 234. Each side end of the metal shells
212 along its entire length is also provided with an
inwardly bent flange 214 to allow the hollow case 210 to be
formed by forcing the flanges 214 to face each other.
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The connecting means 250 may include, for example, a
threaded bolt 252 having a threaded groove 253 and fastened
through the apertures 216 and 234 , a nut 256 fastened to the
threaded bolt 252, and a bolt 254 fastened to the threaded
groove 253 to be used to connect the structural member to
other objects. An end portion of the threaded bolt
projecting inwardly from the reinforcing plate may further
function as the anchor of the filler 140.
There is shown in Figs. 8 and 9 a structural member
employing another connecting means in which a connecting
member 258 is provided with a threaded groove 259 to be
adapted to fasten the threaded bolt 252 instead of the nut
256 as shown in Figs. 6 and 7.
On the other hand, there is shown in Figs. 10 and 11
another reinforcing end piece which is similar to that of
Fig. 1. As shown, the reinforcing end piece 220 includes not
only the through-hole I22, the stepped portion 124 and the
slit portions 126 of the reinforcing end piece I20 as shown
in Fig. 1, but also includes two pairs of parallel ribs 224
inwardly extended along the respective slit portions 126, a
pair of inserting holes 226, each of the holes being located
at an end of each of the ribs 224, and a coupling member 170
having a cylindrical portion 172 at one end thereof to be
inserted into the inserting hole 226 and a stopper portion
174 at the other end for preventing the coupling member I70
from being completely inserted into the inserting hole 226.
The cylindrical portion 172 and the stopper portion 174 are
provided with a threaded groove 176, respectively. A
cylindrical bolt 262 is threaded into the stopper portion
174 to thereby anchor the filler 140 as shown in Fig. 13 and
a bolt 260 is threaded through a bracket(not shown) mounted
in a base (not shown) into the cylindrical portion 172 to
thereby prevent the threaded groove 176 from being plugged
during the filling of the filler 140 as shown in Fig. 12.
After filling of the filler 140, the bolt 260 is removed and
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the threaded groove 176 can be used in connecting the
structural member to other objects by using a suitable
connecting means.
Referring now to Figs. 14 and 15, there is shown
another modified reinforcing end piece of the present
invention. The reinforcing end piece 320 as shown in Fig. 14
is similar to that of Fig. 1 except that a pair of threaded
holes 326 are integrally provided at side walls of the
reinforcing end piece 120 of Fig. 1, respectively, the side
wall being away from a slit portion 126. The cylindrical
bolt 262 and the bolt 260 of Figs. 10 and 11 are threaded to
the threaded-holes 326.
The reinforcing end piece 420 as shown in Fig. 15 is a
combination of the same shown in Figs. 10 and 11 with the
same shown in Fig. 14 except that a pair of threaded-holes
326, instead of the pair of the inserting holes 226 into
which the coupling member 170 is inserted, are employed.
Fig. 16 illustrates a structural member in accordance
with a third embodiment of the present invention. As
illustrated, this structural member 300 comprises a circular
elongated hollow case 400 including three circular thin
metal shells 430, a circular reinforcing plate 410 attached
to an inner surface of each of the metal shells 430 by using
an adhesive such as epoxy resin, soldering, and spot
welding, and a pair of circular reinforcing end pieces 440
engaged with an end portion of the case 400. Each side end
of the metal shells 430 along its entire length is provided
with an inwardly bent flange 420 to allow the hollow case
400 to be formed by facing the flanges 420. The circular
reinforcing end piece 440 is provided with three slit
portions 442 to allow the bent flanges 420 of each of the
metal shells 430 facing each other to be slid therealong.
As described above, although the structural member of
the present invention is of a rectangular shape or a
circular shape, it is not limited to these shapes and may
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have various configurations, e.g., a pentagonal shape, a
hexagonal shape, etc.
Although the invention has been shown and described
with respect to the preferred embodiments, it will be
understood by those skilled in the art that certain changes
and modifications may be made without departing from the
scope of the invention as defined in the following claims.
