Title of Invention

A SYNTHETIC RESIN CORRUGATED PIPE

Abstract (57) Abstract; The presant invention relates to a synthetic resin corrugated pipe comprising a pipe wall having one of an annularly and a helically shaped convex concave surface said convex-concave surface having a plurality of convex portion having a quadrangular cross-sectional shape and a plurality of concave portion having a circular cross-sectional shape. PRICE: THIRTY RUPEES
Full Text



The present invention generally relates to a synthetic resin corrugated pipe which is suitable for indoor/outdoor use and for either above ground or underground use. More specifically, the invention relates to a pipe used for protecting electric wiring, optical fiber cables, electric power cabling and" similar linear structures. Further, the invention relates to multi-pipe lines that include parallel, bundled pipes. Description of the Related Art
A first conventional synthetic resin corrugated pipe contains a pipe wall having an annular- or helical-shaped convex-concave surface. Such a shape improves the strength of the pipe and keeps the pipe from being flattened. The above synthetic resin corrugated pipe is ■used to protect electric wires, to feed water, and the like. In one configuration, a bundle of pipes is provided as a "C.C. BOX"/ which is a multipurpose duct that houses underground electric wires, optical fiber cables, electric power cables, or the like.

Another conventional synthetic resin corrugated

pipe has a pipe wall with a convex-concave surface in which
the concave portions and convex portions are both circular.
Alternatively, a rectangular ■ pipe with a convex-concavo
surface includes a rectangular concave portion and a
rectangular convex portions.
It is difficult to maintain a bundle of circular
pipes parallel because the positional stability of the
circular pipes is poor, especially when such circular pipes
are bundled in parallel, to form a multi-pipe line used
underground because dirt and sand enter between the
circular pipes and disturb the linear alignment of the
.individual circular pipes. Accordingly a cable or wire may
"zigzag" when inserted into the pipe. This problem
increases wiring resistance and makes it difficult to
Conventional rectangular pipes have flat sides
which fit against one another and prevent dirt and sand
from entering between the individual pipes of a multi-pipe
bundle. However, when a wire or cable is inserted into the
rectangular pipe, the wire or cable typically moves toward
a corner portion of the pipe, particularly in a curved portion of the rectangular pipe. Accordingly, the

rectangular pipe has a high wiring resistance and it is
difficult to insert multiple cables therein. Therefore, a rectangular pipe is generally hot used to carry or protect

cables or lines.
SUMMARY OF THE INVENTION
An object of the present inventi'bn is to over coir,= the aforementioned problems of conventional circular or rectangular pipes.
Another object of the present invention is to provide a synthetic resin corrugated pipe having a special structure designed to solve the problems of the conven¬tional pipe.
A third object of the present invention is to
produce a pipe as easily as the conventional pipe, but
., without increased cost and the pipe is designed to have the
same strength against being flattened by pressure as the
conventional pipe, even though the pipe is formed only from
synthetic resin.
More specifically, the synthetic resin corrugated pipe according to the present invention is configured so

that the pipe wall is shaped to have an annular or helical
convex-concave surface. Each convex portion of the convex-
concave surface has a quadrangular cross-sectional shape.
Each concave portion of the convex-concave surface is
shaped to have a circular cross-sectional shape.
Since each of the convex portions has a
Quadrangular shape, the pipe can be laid flat stably and
positioned easily. The flat surface of the pipe prevents


the pipe from being displaced after positioning thereof. The ribs of the circular concave portions project into -the pipe and support the cable and allow the cable to ho inserted into the pipe with minimum resistance.

The present invention further includes a
structure in which a quadrangular fitting pipe portion has
an internal size and shape substantially equal to the
external size and shape of the convex portions which allows
the pipes to be joined easily. The fitting pipe portion is
formed integrally on one end of the pipe and an insertion
connection portion is formed on the other end of the pipe.
.The fitting pipe portion and the insertion connection
portion are fitted together to join the pipes. The
insertion connection portion has a special concave portion
with a size and shape corresponding to those of the convex
portions. The fitting portion and the insertion portion may
be cylindrical.
Furthermore, when multiple pipes are arranged in

a parallel, bundled to form a multi-pipe line, the parallel
alignment of the individual pipes is easily maintained
because of 'the flat surfaces of the convex portions. The
foregoing structure prevents a large amount of dirt, sand
and other contaminants from entering between the individual

-

pipes. Thus, the pipe according to the present invention is highly suitable for underground piping.

Accordingly, the present invention provides a synthetic resin corrugated pipe comprising a pipe wall having one of an annularly- and a helically-shaped convex-concave surface, said convex-concave surface ha^dng a plurality of convex portions ha\ing a quadrangular cross-sectional shape and a plurality of concave portions having a circular cross-sectional shape.
The foregoing and other objects, aspects and advantages will be better understood from the following detailed description of preferred embodiment of the invention with reference to the accompanying drawings in which:
Figure 1 is a perspective view of a pipe showing a first embodiment of the present invention.
Figure 2 is a longitudinal sectional view of a convex portion of the pipe according to the present invention.
Figure 3 is a longitudinal sectional view of a concave portion of the pipe according to the present invention.
Figure 4 is a transverse sectional view of a connection portion of the
pipe according to the present invention.
Figure 5 is a transverse sectional view showing a modified example of
the embodiment of the connection portion of the pipe shown in Figure 4.
Figure 6 is a partially cut-away front view of a pipe according to a
second embodiment of the present invention,
' Figure 7 is a partially cut-away find view of a connection portion of
; the pipe according to the second embodiment of the present invention.

Figure 8 is a partially cut-away front view of a pipe according to a third embodiments of the present invention.
Figure 9 is a partially cut-away front view of a connection portion of the pipe according to the present invention.
Figure 10 is a partially cut-away front view of a pipe according to a modified example of the embodiment show’s in Figure 8,
Figure 11 is a partially cut-away front view of a connection portion of this pipe according to the present .invention.
Figure 12 is a partially cut-away front view of a pipe according to a fourth embodiment of the present invention.
Figure 13 is a partially cut-away front view of




invention.
Figure 14 is a perspective view of a pipe according to a fifth embodiment of the present invention.

Figure 15 is a perspective view illustrating a



bundling of pipes according to the present invention.
Figure 16 is a side view of a connection portion of a bundled pipe line according to the present invention.
Figure 1? is a longitudinal sectional view of a

connection portion of a bundled pipe line according to the
present invention.
Figure 18 is a longitudinal sectional view of thij
same portion of pipe according to the present invention as
shown in Figure 15.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION
Hereinbelow and referring to the attached drawings, preferred embodiments of the present invention will be described. For clarity and ease of understanding, like elements have the same reference numerals throughout the drawings.
Referring to Figures 1-3, a pipe P according to
a first embodiment of the present invention has a pipe wall
1 which has an annular, convex-concave corrugated surface.

The convex portions 2 of the convex-concave corrugated
surface each have an internal and external square cross-
sectional shape with rounded (i.e., arc-shaped) corner
portions. Concave portions 3 of the convex-concave
corrugated surface each have an internal and external circular cross-sectional shape.
The concave portions 2 and convex portions 3 are
alternately disposed along the axis of the pipe. However,
the convex-concave corrugated surface of the pipe wall 1 is
not limited to such an annular convex-concave corrugated
surface, but also may be provided as a helical convex-


ft.

concave corrugated surface or other similar shape. Moreover, the cross-sectional shape of each of the convex portions 2 described herein is not limited to a square shape, but may be a rectangular shape elongated trans¬versely or longitudinally.
As knave by the ordinarily skilled artisan taking the present application as a whole, the pipes P having the aforementioned structure can be formed by many methods, including extruding melted resin into a known caterpillar-type, pipe-forming consecutive mold from a resin extruder to form a tube. Generally, high-pressure air is blown into -the tube or air is sucked from the mold simultaneously, whereby the melted tube is pressed against the mold to continuously form the pipes P. The synthetic resin material for forming the pipe wall 1 of the pipe P of the present invention can include, polyethylene, polyvinyl chloride, polypropylene and/or any other suitable synthetic resin material. The pipe P is preferably formed solely from synthetic resin.
Figures 4 and 5 respectively show first and second joints for connecting the pipes P. In the connection joints shovm in Figure 4, square ring-shaped pickings 12 each have a circular cavity of a size substantially equal to that of the concave portion 3 and a square external circumference,' size and shape analogous to

the circumference, size and shape of the convex portions 2, but larger than the external size and shape of the convex portions 2.
When joining first and second pipes P, the ring-shaped packings 12 are fitted onto the end portions of the first and second pipes P and then the first and second pipes P are pressed into a rectangular pipe-shaped joint 10 from opposite sides. The pipe-shaped joint 10 has recesses for accommodating the packings 12. Another ring-like packing 11 is interposed between the end surfaces of the first and second pipes P to seal the pipesIn the connection joint shown in Figure 5, square
ring-shaped packings 13 each have a channel-shaped cross-
section. To form the joint, the packings 13 are fitted
onto the convex portions 2 located near the end portions of
first and second pipes P. The first and second pipes P are
pressed into a rectangular pipe-like joint 10. Other ring-
IH shaped packings 11 are interposed between opposite sides fan intermediate re-entrant groove 10a of the joint 10. The re-entrant groove 10a is a groove which presses the '«^ packings 11 against the ends of the pipes P. Further, motion stop pins 14 are fitted onto the outer circumference •X) of the joint for securing the joint and ensuring the pipes


are reliably coupled together.
A second embodiment is shown in Figures 6 and 7.

A difference between the first and second embodiments is that the second embodiment has a -quadrangular-section fitting pipe-shaped portion 4 which has an internal sizu and shape substantially equal to those of a convex portion 2. Further, a re-entrant groove 4a is continuously and integrally formed on one end side h (e.g., the right end side in Figure 6) of a pipe P. An insertion connection portion 5 has a special concave portion 3a continuously and integrally formed on a second end side c. (e.g., a left side in Figure 6) of the pipe P.
To connect pipes P, as shown in Figure 7, a
■■ rectangular-section 0-ring 15 is fitted into the special
concave portion 3a. The outer circumferential portion of
the 0~ring 15 projects over the convex portions 2. To form
the joint, the pipe section c. is pressed into the
rectangular fitting pipe-like portion 4 so that the outward
projecting portion of the 0-ring 15 fits into the
re-entrant groove 4a.
Although the embodiment shown in Figure 5 has an
and a special concave portion 3B., the insertion connection portion 5 is not always needed. That is, as a modified
insertion connection portion 5 vjhich has a concave portion
quadrangular fitting pipe-like portion 4 formed on one end side b^ of the pipe.

To connect pipes with such a configuration, the pipe should be cut, such as along line a_. Then, the cut end portion of the pipe body portion a_ can be connected to the portion 4 in the same manner as shown in Figure 7, or the cut end portions can be connected using the joint 10 illustrated in Figures 4 and 5. The structure illustrated in Figures 6 and 7 is advantageous since the pipe body portion can be cut into a desired length at an arbitrary point and easily joined to the next section of pipe.



A third embodiment of the present invention is illustrated in Figures 8 and 9 and differs from the second ■. embodiment by the fitting pipe-like portion 4 formed on one end side b_ (the right side in Figure 8) being cylindrical and a semicircular re-entrant groove 4a being formed along the inner surface of the portion 4. The male side connection portion 5 on a second end c. (e.g., left side in Figure 8) is shaped like a cylinder and a semicircular re-entrant groove 5a is formed in the outer circumferential surface of the portion 5. A circular-section 0-ring 15 is fitted into the groove 5a. The inner circumferential surface of the re-entrant groove 5a has a diameter
substantially equal to that of the inner circumferential
surface of the concave portion 3.
To connect pipes P having the configuration shown in Figures 8 and 9, the circular section 0-ring 15, is

fitted into the re-entrant groove 5a in the cylindrical insertion connection portion 5 of a first pipe P. The outer circumferential portion of the 0-ring projects over the outer circumferential surface. The cylindrical insertion connection portion 5 is pressed into the cylindrical fitting pipe-like portion 4 in a second pipe P and the outward projecting portion of the 0-ring 15 fits into the re-entrant groove 4a, to thereby connect the pipes,
Figures 10 and 11 show a modified example of the third embodiment of the present invention, in which the ■ diameter of the outer circumference of the cylindrical-section fitting pipe-shaped portion 4 on the right end side
h_ is substantially equal to that of the outer surface of
the quadrangular convex portion 2. The diameter of the
inner circumference of the cylindrical-section, insertion
connection portion 5 located on the left end side c_ is
shaped so as to be inserted in the fitting pipe-like



The outer circumferential surface of the fitting pipe-like" portion 4 is shaped so as not to project over the

outer circumference of the pipe body portion a_. This structure allows a plurality of pipes to be aligned, without increasing the size of the connection portion between the pipes and is especially useful when a multi-pipe line is formed. If the inner surface of the insertion connection portion 5 is shaped in the same manner as illustrated in Figures 10 and 11, a cable can be inserted with minimum resistance and effort. As easily understood by the ordinarily skilled artisan within the purview of the present application, the above feature can be applied to the structure of the connection portion in any of the other ■embodiments described herein.
-■4

The fitting portion 4 illustrated in Figures 10
and 11 has a flat pipe-shape having an inner circum¬
frenetically surface in which no re-entrant groove 4a is
formed. Depending upon the specific application,
re-entrant grooves 4a and 5a need not always be provided in two fitting surfaces. In some applications, a re-entrant
groove 4a need be formed only in either one of the two
fitting surfaces. Alternatively, a groove need not be
formed in either surface. Further, the sealing means is not limited to the 0-ring 15, but can include other similar
integrally vita the inner surface of the fitting portion 4. Figures 12 and 13 show the structure of a fourth

embodiment of the invention, in which the pipe P is cut into a desired length as a concave 'portion 3 to thereby form a structure in which connection is made without a joint. A difference between the fourth embodiment and the previous embodiments is that the fourth embodiment has a cylindrical fitting pipe-like portion 4 with a re-entrant groove 4a which is continuously formed on one end portion b^ and each concave portion 3 in the pipe body portion a. has a cylindrical shape c_ and a re-entrant groove 5a in its outer circumferential surface.
In the fourth embodiment, the cylinder c_ of the
■ concave portion 3 can be used advantageously as an
insertion connection portion for connection to the fitting
pipe-like portion 4. An arbitrary length portion can be
cut if the length is too large to connect the pipe P for
the specific application. The connection method for this
erabodiment is the same as that of the third embodiment and,
for brevity, the description thereof will be omitted.
Figure 14 illustrates a fifth embodiment having
a pipe structure suitable for close arrangement of a large
number of pipes, such as a multi-pipe line B shown in
Figure 15. The pipe P is configured so that suitably sized
projections 6 are formed on the outer circumferential
■ surfaces of two sides 2a (e.g., front side and lower side
in Figure 14) of the convex portions 2 in the pipe P. The


size of the projections is advantageously selected by the designer depending on the desired ease of connection (e.g., in which case shorter connections would be employed) and the desired rigidity (e.g., in which case longer connections would be employed) of the pipeline. Cavities 7 which receive the projections 6 are formed on upper side and back side 2b in Figure 14. Alternatively, in Figure4, the surfaces where projections 6 and cavities 7 are
formed may be selected to be a combination of the front and
back surfaces or any other logical combination of the upper
and lower surfaces, respectively
The number of cavities 7 and projections 6 will vary depending upon the specific application. When two (or an even number 01) projections 6 or cavities 7 are formed on any one surface as shown in Figure 14, one of the two structures aria be formed as a projection 6 and the other may be formed as a cavity 7. In short, as shown in Figure
15, projections and cavities are formed suitably so as to
be fitted together when pipes P are arranged in a bundle.
Depending upon the designer's requirements and
constraints, projections 6 and cavities 7 need not be
formed on all sides of a convex portion 2. For example,
projections 6 and cavities 7 may be formed simply on the
front and back surfaces, or upper and lower surfaces of the
convex portion 2, or formed- alternately on the convex

portions 2.
To connect the bundled multi-pipe lines B, a rectangular packing 25 is pressed against an end surface oi a multi-pipe line B, as shown in Figures 16 to 18. The rectangular packing 25 has a corresponding number of holes suitably sized to insert the concave portions 3 of the pipes therein to. An annular packing 26 is fitted onto the outer circumferential surface of a convex portion 2 (or a concave portion 3) at a predetermined distance from the end surface of the multi-pipe line B. The end portions of the pipes are pressed into a pipe-like portion 22 of a ..rectangular pipe-like joint 20.
An adhesive hardening liquid 27 is advantageously injected into a space between the two packings 25 and 26 through a small hole 23 formed in the pipe-like portion 22 of the joint, so that the space is filled with the adhesive hardening liquid 27. Such adhesive hardening liquids are well-known and commonly available to ordinarily skilled artisans. The multi-pipe lines B formed as described above
are positioned flat against each other.
The flat portions of two rectangular pipe-like
flanges 21 opposing each other are tightened and connected
by using fasteners through the holes 24 formed in the
flanges 21. Although description is omitted herein, it ^■■'

will be understood by the ordinarily skilled artisan that multi-pipe lines may be connected by any of a variety of other suitable means.
The hardness of a synthetic resin material for forming the pipe used in the present invention may be selected according to a number of considerations such as the size of the pipe to be produced, the area where the pipe will be used, and the like. For an underground pipe, a material having a relatively high hardness and high water resistance is preferably selected, so as to prevent pressure flattening, and taking into account the external . pressure acting on the pipe wall 1.
Although preferred embodiments of the present invention have been described above, it will be understood by the ordinarily skilled artisan that the present invention is not limited to the structure shown in the foregoing embodiments and that changes may be made suitably without departing from the range of embodiments shown so
long as the objects of the present invention are achieved.
Thus, the invention can be practiced with modification
, within the spirit and scope of the appended claims.
As described above, according to the present


Invention, a pipe has a convex-concave shaped corrugated surface with convex portions having a quadrangular cross-sectional shape and concave 'portions having a circular

cross-sectional shape. The pipe according to the present
invention is advantageously shaped to-prevent the pipe from'
undesirable shifting or movement. Furthermore, the concavo
portions of the inventive pipe allow a wire or cable to be
inserted into the pipe with minimal resistance.
Also, the pipe according to the present invention
is easily formed into multi-pipe lines because the convex
portions are position able flat against one another. Since
such a multi-pipe line has little space between the
individual pipes, the multi-pipe line prevents dirt and
sand from accumulating between individual pipes. This
.feature is particularly useful when pipes are buried
underground, and helps maintain the parallel, bundled
configuration of the pipes and minimize disturbance of the
linear and parallel alignment of the lines within the pipe.
Therefore, the pipe according to the present invention is
highly suitable as an underground pipe, and further is
produced economically and without increased cost.
Additionally, the pipe according to the invention
has the same strength against being flattened by pressure
as the conventional pipe, even though the pipe according to
the present invention is formed only of synthetic resin.


WE CLAIM:
1. A synthetic resin corrugated pipe comprising a pipe wall having one of an annularly- and a helically-shaped convex-concave surface, said convex-concave sur&ce having a plurality of convex portions having a quadrangular cross-sectional shape and a plurality of concave portions having a circular cross-sectional shape.
2. The synthetic resin corrugated pipe according to claim 1, wherein each of said convex portions has a square cross-section shape with arc-shaped comers.
3. The synthetic resin corrugated pipe according to claim 1, wherein said convex portions have a plurality of projections and a plurality of cavities for receiving said projections, formed on outer circumferential surfaces of said convex portions.
4. The synthetic resin corrugated pipe according to claim 1, wherein a first end of smd pipe has a quadrangular fitting portion having an internal dimension substantially similar to that of an external dimension of said convex portions.
5. The synthetic resin corrugated pipe according to claim 4, wherein a
4 second end of said pipe has a male connection portion said male connection
portion including a special concave portion.


6. The synthetic resin corrugated pipe according to claim 1, wherein a
first end of said pipe has a fitting portion having a cylindrical cross-sectional
shape.
7. The synthetic resin corrugated pipe according to claim 6, wherein a
second end of said pipe has a male connection portion having a cylindrical
cross-sectional shape, said male connection portion for being positioned in
said fitting portion.
8. The synthetic resin corrugated pipe according to claim 6, wherein a
diameter of an outer surfece of said cylindrical fitting portion is substantially
equal to a length of a side of said quadrangular convex portion.
9. The synthetic resin corrugated pipe according to claim 7, wherein an inner surface of said male connection portion has a cylindrircal cross-sectional shape and a diameter similar to a diameter of an inner surface of one of said concave portions.
10. A pipeline comprising a synthetic resin corrugated pipe as claimed in any one of the preceding claims.
I

Documents:

233-mas-1996 abstract.jpg

233-mas-1996 abstract.pdf

233-mas-1996 claims.pdf

233-mas-1996 correspondence-others.pdf

233-mas-1996 correspondence-po.pdf

233-mas-1996 description(complete).pdf

233-mas-1996 drawings.pdf

233-mas-1996 form-2.pdf

233-mas-1996 form-26.pdf

233-mas-1996 form-4.pdf

233-mas-1996 form-6.pdf

233-mas-1996 others.pdf

233-mas-1996 petition.pdf


Patent Number 193239
Indian Patent Application Number 233/MAS/1996
PG Journal Number 35/2005
Publication Date 16-Sep-2005
Grant Date 21-Jun-2005
Date of Filing 13-Feb-1996
Name of Patentee SHRI. CHIZUKO KANAO
Applicant Address 9-18 NANPEIDAI 4-CHOME, TAKATSUKI-SHI, OSAKA
Inventors:
# Inventor's Name Inventor's Address
1 SHIRO KANAO 9-18 NANPEIDAI 4-CHOME, TAKATSUKI-SHI, OSAKA
PCT International Classification Number F16L9/00
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 HEI 7-50602 1995-02-14 Japan