U.S. patent application number 09/760729 was filed with the patent office on 2001-07-19 for coupling structure for tube.
Invention is credited to Kikumori, Yasuhiro, Koizumi, Yoshiyuki.
Application Number | 20010008342 09/760729 |
Document ID | / |
Family ID | 18537438 |
Filed Date | 2001-07-19 |
United States Patent
Application |
20010008342 |
Kind Code |
A1 |
Kikumori, Yasuhiro ; et
al. |
July 19, 2001 |
Coupling structure for tube
Abstract
An engaging member 15 is integrally or separably attached to the
tip end of a second tube member 2 which is attached to the side
wall 30 of a hand hole. A come-out preventing member 24 is adapted
to be attached to the tip end of a first tube member 1 which is
coupled to the second tube member 2. When the come-out preventing
member 24 is pushed on the engaging member 15 side, both the
engaging member 15 and the come-out preventing member 24 are placed
in an engagement state mutually so that the first tube member 1 and
the second tube member 2 are coupled without being drawn.
Inventors: |
Kikumori, Yasuhiro; (Osaka,
JP) ; Koizumi, Yoshiyuki; (Osaka, JP) |
Correspondence
Address: |
MCGINN & GIBB, PLLC
8321 OLD COURTHOUSE ROAD, SUITE 200
VIENNA,
VA
22182-3817
US
|
Family ID: |
18537438 |
Appl. No.: |
09/760729 |
Filed: |
January 17, 2001 |
Current U.S.
Class: |
285/319 |
Current CPC
Class: |
Y10S 285/921 20130101;
F16L 25/0036 20130101; F16L 25/0045 20130101; Y10S 285/903
20130101 |
Class at
Publication: |
285/319 |
International
Class: |
F16L 039/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 18, 2000 |
JP |
P. 2000-009265 |
Claims
What is claimed is:
1. A coupling structure for a tube having first and second tube
members which are coupled to each other comprising: a come-out
preventing member adapted to be held at an outer periphery of said
first tube member in a state being restricted in its movement in a
longitudinal direction of said first tube member at a tip end
portion on a coupling side of said first tube member; and an
engaging member adapted to protruded from an end portion on a
coupling side of said second tube member, wherein said come-out
preventing member and said engaging member are respectively
provided with engaging portions which act to engage said come-out
preventing member and said engaging member to each other to prevent
said first and second tube members from being separated from each
other in a state where said come-out preventing member is coupled
with said engaging member, and wherein at least one of said
engaging portions has elasticity with respect to a radial direction
of said tube member or elastically supported so that said engaging
portions are placed in an engaged state to each other due to the
elasticity of said at least one of said engaging portions when said
come-out preventing member is pushed into said engaging member.
2. The coupling structure for a tube according to claim 1, wherein
said engaging member is threadedly engaged with said second tube
member so as to be separatable from said second tube member in a
state where said engaging member and said come-out preventing
member are engaged to each other.
3. The coupling structure for a tube according to claim 1, further
comprising: a packing adapted to be housed in a packing housing
portion of said second tube member in a state where said packing is
fitted on an outer periphery of said tip end portion on said
coupling side of said first tube member, wherein said come-out
preventing member is attached to an inner side from said packing in
said longitudinal direction of said first tube member.
4. The coupling structure for a tube according to claim 3, wherein
the tip end of said come-out preventing member is brought in
contact with an end surface of said packing, to thereby support
said packing from a rear portion side thereof along a pushing
direction when said packing is pushed within said packing housing
portion of said second tube member.
5. The coupling structure for a tube according to any one of claims
1 to 4, wherein said first tube member is a spiral corrugated tube
having a spiral-shaped projection on the outer periphery thereof,
wherein said spiral corrugated tube is arranged in amanner that
said come-out preventing member meshes with said spiral-shaped
projection to restrict the movement of said come-out preventing
member in the longitudinal direction of said tube member.
6. The coupling structure for a tube according to any one of claims
1 to 4, wherein said engaging member is threadedly engaged with and
attached to said end portion on said coupling side of said second
tube member when said engaging member is coupled with come-out
preventing member, and wherein said engaging member can be
separated from said end portion on said coupling side by releasing
the threadedly engaged state.
7. The coupling structure for a tube according to claim 5, wherein
said engaging member is threadedly engaged with and attached to
said end portion on said coupling side of said second tube member
when said engaging member is coupled with come-out preventing
member, and wherein said engaging member can be separated from said
end portion on said coupling side by releasing the threadedly
engaged state.
8. The coupling structure for a tube according to any one of claims
1 to 4, wherein said first tube member is a cable protection tube
for an electric wire cable and is buried within ground, and said
second tube member is a conduit opening member which is buried in a
side wall of a hand hole made of concrete and serves to introduce
said cable passed through said first tube member within said hand
hole.
9. The coupling structure for a tube according to claim 5, wherein
said First tube member is a cable protection tube for an electric
wire cable and is buried within ground, and said second tube member
is a conduit opening member which is buried in a side wall of a
hand hole made of concrete and serves to introduce said cable
passed through said first tube member within said hand hole.
10. The coupling structure for a tube according to claim 6, wherein
said first tube member is a cable protection tube for an electric
wire cable and is buried within ground, and said second tube member
is a conduit opening member which is buried in a side wall of a
hand hole made of concrete and serves to introduce said cable
passed through said first tube member within said hand hole.
11. The coupling structure for a tube according to claim 7, wherein
said first tube member is a cable protection tube for an electric
wire cable and is buried within ground, and said second tube member
is a conduit opening member which is buried in a side wall of a
hand hole made of concrete and serves to introduce said cable
passed through said first tube member within said hand hole.
12. The coupling structure for a tube according to claim 2, wherein
said engaging member is threadedly engaged with said second tube
member so as to be separatable from said second tube member by
rotating said engaging member relative to said second tube member
in a state where said engaging member and said come-out preventing
member are engaged to each other.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to a coupling structure for a
tube which is used, for example, at the time of burying a cable
such as a wire cable in the ground, for attaching a protection tube
used for protecting the cable to a hand hole made of concrete, and
also includes a coupling structure for a tube used for coupling
various types of tubes.
[0002] Conventionally, as a means for attaching a cable protection
tube made of composite resin to a hand hole, there is provided such
an arrangement shown in FIG. 13 that a through hole 52 is provided
at the side wall 51 of the hand hole made of concrete which is
provided in advance, then the tip end of a protection tube 53 is
inserted into the through hole 52, and mortar 54 is filled into a
space between the protection tube 53 and the through hole 52 to
thereby fix the protection tube. A reference numeral 55 depicts a
bellmouth attached to the tip end of the protection tube 53.
[0003] However, this method requires troublesome procedures such as
the hole making procedure at a construction site, the filling
procedure of mortar etc. Further, the next procedure can not be
started until the mortar thus filled is hardened. In this manner,
this method has a defect that the troublesome procedure and much
time is required.
[0004] As a means for solving such a problem, Japanese Patent
Examined Publication No. Sho. 60-14568 discloses such an
arrangement that, at the time of providing a hand hole, a conduit
opening member provided separately from a protection tube at the
outer periphery thereof is buried in advance such that the end
portion thereof protrudes on the outer side of the hand hole, and
the protruded end portion is coupled with the end portion of the
protection tube by using another joint tube. In this case, as each
of the protection tube and the conduit opening member, a spiral
corrugated tube with the same diameter having a spiral projection
portion on the outer periphery thereof is employed. The joint tube
engages with the protection tube and the conduit opening member so
as to extend both of them by using the spiral projection portions
thereof.
[0005] However, the method of the aforesaid publication also
requires a procedure of screwing the joint tube into the protection
tube and the conduit opening member. In this case, it is required
to hold the protection tube and the conduit opening member so as to
be arranged in a straight line during the screwing procedure. In
particular, since the protection tube is very long and has been
wound in a roll shape before installation, the protection tube
likely holds its rolled shape, it is difficult to hold the
protection tube and the conduit opening member in a straight
shape.
[0006] Further, since the protection tube and the conduit opening
member are coupled simply by means of the joint tube, there is a
disadvantage that water in the ground likely enters into the gap
therebetween.
SUMMARY OF THE INVENTION
[0007] Accordingly, an object of the invention is to provide a tube
coupling structure which can eliminate the aforesaid conventional
drawbacks, can perform simply in a short time a coupling procedure
at the time of coupling tubes like a case of coupling a conduit
opening member buried in a hand hole with a cable protection tube,
and is excellent in watertightness.
[0008] In order to solve the aforesaid problem, the invention is
characterized by including a come-out preventing member which is
held at an outer periphery of a first tube member of a pair of tube
members to be coupled to each other in a state being restricted in
its movement in a longitudinal direction of the first tube member
at a tip end portion on a coupling side of the first tube member,
and an engaging member protruded from an end portion on a coupling
side of a second tube member which is the other of the pair of tube
members, wherein the come-out preventing member and the engaging
member are respectively provided with engaging portions which act
to engage the come-out preventing member and the engaging member to
each other to prevent the first and second tube members from being
separated to each other in a state where the come-out preventing
member is pushed into the engaging member, and wherein at least one
of the engaging portions has elasticity with respect to a radial
direction of the tube member or elastically supported so that the
engaging portions are placed in an engaged state to each other due
to the elasticity of the at least one of the engaging portions when
the comae-out preventing member is pushed into the engaging
member.
[0009] In the aforesaid arrangement, it is preferable to have an
arrangement in which the engaging member is threadedly engaged with
the second tube member so as to be separatable from the second tube
member by rotating the engaging member relative to the second tube
member while the engaging member and the come-out preventing member
are being engaged to each other. With this arrangement, the
coupling state between the first and second tube members can be
easily released by the rotation thereof even after the coupling in
the longitudinal direction.
[0010] In the above-mentioned structure, it is advantageous that a
packing is provided which is housed in a packing housing portion of
the second tube member in a state where the packing is fitted on an
outer periphery of the tip end portion on the coupling side of the
first tube member, and the come-out preventing member is attached
to an inner side from the packing along the longitudinal direction
of the first tube member.
[0011] In this case, it is further advantageous that the come-out
preventing member abuts its tip end against an end surface of the
packing to thereby support the packing from a rear portion side
thereof along a pushing direction when the packing is pushed within
the housing portion.
[0012] Further, it is considered that the first tube member is a
spiral corrugated tube having a spiral-shaped projection on the
outer periphery thereof, and the spiral corrugated tube is arranged
in a manner that the come-out preventing member meshes with the
spiral-shaped projection to restrict movement the come-out
preventing member in the longitudinal direction of the tube
member.
[0013] According to this, there is provided an arrangement that the
engaging member is arranged in a manner that it is meshed with and
attached to the end portion on the coupling side of the second tube
member and separated from the end portion on the coupling side by
releasing the meshed state.
[0014] Further, in the present invention, there may be provided an
arrangement that the fist tube member is a cable protection tube
for an electric wire cable etc. buried within ground, and the
second tube member is a conduit opening member which is buried in a
side wall of a hand hole made of concrete and serves to introduce
the cable passed through the first tube member within the hand
hole.
[0015] In this invention, the tube members include not only members
generally called tubes but also other tubular members such as joint
tubes.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 shows an exploded perspective view of the coupling
portion between a conduit opening member and a cable protection a
tube according to an embodiment of the invention;
[0017] FIG. 2 shows a sectional view showing a state just before
the coupling of the protection tube to the conduit opening member
buried in a hand hole;
[0018] FIG. 3 shows a perspective view showing a state just before
a packing is attached to the tip end of the protection tube;
[0019] FIG. 4 shows a sectional view showing a state where the
protection tube is coupled to the conduit opening member buried in
a hand hole;
[0020] FIG. 5 shows an enlarged diagram of a main portion in FIG.
4;
[0021] FIG. 6 shows an enlarged sectional view of a main portion
showing a state where the protection tube is being inserted into
the conduit opening member;
[0022] FIG. 7 shows a sectional view of a main portion showing a
state just after an engaging member is separated and the protection
tube is drawn out of the conduit opening member;
[0023] FIG. 8 shows a sectional view showing a state where the
conduit opening member is cut and separated so as to make coincide
with the thickness of the side wall of the hand hole;
[0024] FIG. 9 shows a sectional view showing a state where the
divided members divided in FIG. 7 are coupled again;
[0025] FIG. 10 shows a sectional view showing a state where the tip
end of the conduit opening member is cut, then a joint member is
coupled to the bellmouth and buried within the side wall;
[0026] FIG. 11 shows a sectional view showing the coupling
structure between a conduit opening member and a protection tube in
a hand hole according to another embodiment of the invention;
[0027] FIG. 12 shows an enlarged diagram showing a main portion in
FIG. 11; and
[0028] FIG. 13 shows a sectional view showing the conventional
coupling structure of a protection tube to a hand hole.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0029] An embodiment described below shows a case where the
invention is implemented in the coupling between a conduit opening
member for a hand hole and a protection tube. In FIG. 1, 1 depicts
the protection tube serving as the first tube-member of the
invention. The protection tube 1 is a corrugated tube made of hard
composite resin having a spiral-shaped projection portion 2 on the
outer periphery thereof. In general, the protection hole is brought
into a construction site in a long rolled state and buried into the
ground.
[0030] 3 depicts a conduit opening member for burying a hand hole
serving as the second tube member of the invention. The main body
portion 4 of the conduit opening member 3 is configured in a manner
that one end portion side thereof is formed as a corrugated tube
having many annular projection portions 5 on the outer periphery
thereof and the other end portion thereof is formed as a spiral
corrugated tube having a spiral projection portion 6 on the outer
periphery thereof. A straight portion 8 with a small diameter is
formed at the tip end of the main body portion on the annular
projection portions 5 side through a tapered step portion 7. A
bellmouth 9 is formed at the tip end of the straight portion. On
the other hand, a large-diameter cylindrical portion 11 is formed
at the tip end of the main body portion on the projection portion 6
side through a step portion 10 which elects almost perpendicularly
from the outer periphery of the main body portion. A male screw 12
is formed on the pouter periphery of the tip end portion of the
large-diameter cylindrical portion 11. As described later, a hollow
portion within the large-diameter cylindrical portion 11 serves as
a packing housing portion 13.
[0031] 15 depicts an engagement member of the invention which is
configured entirely by a large diameter portion 16 and a small
diameter portion 17 to form a step-type short cylindrical shape and
is also formed by hard composite resin like the conduit opening
member 3. A female screw 18 fitting to the male screw 12 is formed
on the innerperipheryof the large diameter portion 16. Further, a
plurality of engagement projections 19, 19 are formed with an
interval along the circumferential direction integrally on the
inner peripheral surface at the end portion of the small diameter
portion 17 on the large-diameter portion side. As described later,
each of the projections 19 is configured almost in a V shape in a
manner that one surface at opposite side to the large diameter
portion 16 is formed as a gentle slanted surface 20.
[0032] 22 depicts a supporting ring serving as a supporting member
of the invention. The supporting ring has an inner diameter which
is slightly larger than the maximum outer diameter of the
protection tube 1 and is formed in a straight shape so as not to
incline to the axial direction in a state that the supporting ring
is fitted on the outer periphery of the protection tube 1. A pair
of supporting pieces 23, 23 opposing to the radial direction are
protrusively provided on and integrally with the one end side of
the supporting ring 22. These supporting rings 22, 22 have a thin
thickness and elasticity, and further are integrally and
continuously provided at the tip ends thereof with come-out
preventing members 24 which are bent in the same direction as the
circumferential direction of the supporting rings 22. The outer
periphery of each of these come-out preventing members 24 is formed
as a slanted surface 25 which becomes lower toward the tip end
surface at the opposite side of the supporting rings 22.
[0033] Further, two projections 26, 26 are provided on the inner
peripheral surface of each of the come-out preventing members 24,
24 along an imaginary spiral passing on the inner peripheral
surface. This imaginary spiral has the same pitch as the spiral
formed on the outer periphery of the protection tube 1. These
come-out preventing members are arranged in a manner that the
come-out preventing members can mesh with the outer side of the
protection tube 1 by fitting the projections 26, 26 in the groove
between the projection portions 2 of the protection tube 1 and
rotating the come-out preventing members. These come-out preventing
members 24, 24 also have a thin thickness and have such elasticity
that they bend inward when applied with force from the outer
periphery side. These supporting rings 22 and the come-out
preventing members 24 are usually formed integrally by hard
composite resin.
[0034] 27 depicts a packing which is formed by soft rubber in an
annular shape as a whole. The packing is provided on the inner
periphery thereof with spiral groove 28 which fits to the
projection portion 2 of the protection tube 1 and further provided
on the outer periphery thereof with a plurality of annular finny
pieces 29 which are disposed with an interval in the axial
direction.
[0035] A method of coupling to the hand hole by using the
protection tube 1 and the conduit opening member 3 thus configured
will be explained. First, as shown in FIG. 2, at the time of
providing concrete at a hand hole side wall 30, the conduit opening
member 3 is buried in a manner that the opening portion of the
bellmouth 9 thereof almost fits to the inner wall surface of the
side wall 30 and at least the male screw 12 of the large-diameter
cylindrical portion 11 at the opposite side of the bellmouth
exposes from the outer wall surface of the side wall 30. The
engagingmember 15 is attached to the large-diameter cylindrical
portion 11 by meshing the female screw 18 of the engaging member
with the male screw 12. This attachment procedure may be performed
before or after the provision of the concrete.
[0036] The protection tube 1 is coupled to the conduit opening
member after the concrete of the side wall 30 is hardened. First,
as shown in FIG. 3, an integration unit of the ring 22 and the
member 24 is fitted from the supporting ring 22 side on the outer
periphery of the protection tube 1 at the end portion of the
coupling side of the protection tube 1. Further, the projections 26
of the come-out preventing members 24 are fitted into the groove
between the portions 2 of the protection tube 1 and are meshed with
the groove while being rotated, whereby the integration unit is
attached to the protection tube. Thereafter, the packing 27 is
fitted on and attached to the outer periphery of the tip end of the
protection tube 1 such that the spiral groove 28 is fitted to the
projection portion 2. In this case, in order to facilitate the
attachment procedure of the packing, the come-out preventing
members 24 are moved backward toward the inside from the normal
position, then after the attachment of the packing 27 the come-out
preventing members are rotated in a direction opposite to the
screwing direction to be moved to the tip end side of the
protection tube, and as shown in FIG. 2 the tip ends of the members
24 are abutted against the end surface of the packing 27.
[0037] The protection tube 1 to which the come-out preventing
members 24 and the packing 27 are attached in the aforesaid manner
is inserted from the packing 27 side into the end portion of the
small diameter portion 17 side of the engaging member 15 and then
pushed in until the packing 27 enters into the packing housing
portion 13 within the large-diameter cylindrical portion 11 of the
conduit opening member 3, as shown in FIG. 2. on the way of the
pushing procedure, as shown in FIG. 6, the slanted surface 25 on
the outer periphery of the come-out preventing member 24 abuts
against the engagement projection 19 of the engaging member 15.
When the protection tube is further pushed in this state, the
come-out preventing members 24 slide while being bend inward due to
the elasticity of the come-out preventing members 24 in accordance
with the action of the slanted surface 25 thereof. Finally, in the
stage where the packing 27 is pushed within the packing housing
portion 13 in a watertight, the come-out preventing members 24
restore and an engagement portion 21 which is the end surface on
the rear surface side of the come-out preventing member 15 engages
with the inner side of the engagement projection 19, whereby the
come-out preventing member is held so as not to come out.
[0038] The come-out preventing member is engaged only with respect
to the axial direction of the tube and not engaged with respect to
the circumferential direction. Thus, in such an engagement state,
the come-out preventing member 24 and the engaging member 15 are
rotatable mutually, so that the engaging member 15 can be removed
from the conduit opening member 13 by rotating the engaging member
15 to thereby cancel the meshing state between the screws 12 and
18.
[0039] In this manner, in a state where the packing 27 and the
members 24 are attached to the protection tube, the protection tube
1 can be coupled to the conduit opening member by the one-touch
operation by merely pushing the protection tube to the conduit
opening member 3 side.
[0040] In this respect, in order to allow the come-out preventing
member 24 to bend inward as described above, a margin gap $ is
provided between the inner surface side of the engaging member 15
and the external surface side of the protection tube 1. Although
the come-out preventing member 24 likely falls down in the axial
direction due to the presence of the margin gap S, the supporting
ring 22 which inner surface is formed in a straight fashion serves
as a supporting member for preventing the falling-down of the
come-out preventing member.
[0041] At the time of the aforesaid pushing operation, the tip end
of the come-out preventing member 24 abuts against the end face on
the rear surface side of the packing 27 to thereby support the
packing 27 form the rear portion side along the pushing direction.
Further, the come-out preventing member 24 is meshed with the
protection tube 1 and so restricted in its position not to move in
the axial direction. Accordingly, the packing 27 is prevented from
moving in the axial direction with respect to the protection tube 1
due to the sliding resistance at the time of the pushing operation
and so the packing can be surely pushed within the packing housing
portion 13.
[0042] As described above, the engaging member 15 is rotatable
after coupling the protection tube 1 to the conduit opening member.
Thus, when the engaging member 15 is rotated in such a direction of
releasing the meshing state with the male screw 12 of the conduit
opening member 3, partially the come-out preventing members 24
rotate together with the engagement member, as shown in FIG. 7, the
engagement member can be drawn to the protection tube 1 side. Then,
the protection tube can be removed by drawing the protection tube 1
from the conduit opening member 3. Accordingly, even when there is
any problem after coupling the protection tube to the conduit
opening member, the coupling state therebetween can be cancelled
easily to restore the original state, so that the maintenance can
be facilitated.
[0043] FIGS. 8 and 9 show a case where the thickness of the hand
hole side wall 30 is small as compared with the length of the
conduit opening member 13. In this case, when the tapered step
portion 7 is cut at the both sides thereof between the straight
portion S and the main body portion 4, the conduit opening member
is divided in two units in a state that the tapered step portion 7
is removed. Then, as shown in FIG. 9, the end portion of the
cut-out side of the straight portion 8 is inserted within the end
portion of the main body portion 4 by a necessary length so as to
adjust the length such that the inserted length of the end portion
of the straight portion fit to the thickness of the side wall 30 to
be buried.
[0044] To be more concrete, the outer diameter D of the straight
portion 8 is slightly smaller than the inner diameter E on the
cut-out side of the main body portion 4, so that the straight
portion 8 can be inserted within the main body portion 4 thus
separated with a little gap therebetween. In such an insertion
state, an adhesive or stick tape 31 is wound in a sealed state so
as to extend between the main body portion 4 and the straight
portion 8 to thereby couple integrally them and these portions thus
integrated are buried within the side wall 30.
[0045] On the other hand, when the thickness of the side wall 30 is
too large as compared with that of the conduit opening member 3, as
shown in FIG. 10, the potion 4 is cut at the boundary between the
portions having the spiral projection portion 6 and the annular
projection portions 5 to thereby cut off the portion side having
the annular projection portion 5. Thereafter, one end of a joint
member 32 formed by a spiral corrugated tube is meshed with the
inner side of the spiral projection portion 6 to extend the entire
length of the conduit opening member so as to coincide with the
length corresponding to the thickness of the side wall 30, then the
spiral corrugated tube portion of another bellmouth 33 is attached
to the tip end of the conduit opening member thus extended and the
conduit opening member is buried. The protection tube 1 may be used
as the joint member 31 by cutting the protection tube in a required
length. In this case, the spiral pitch of the spiral projection
portion 6 is set so as to be same as that of the protection tube 1,
and further the inner diameter of the spiral projection portion is
set to be slightly larger than the inner diameter of the protection
tube 6 or the outer diameter of the spiral projection portion is
set to be slightly smaller than the inner diameter of the
protection tube 1 when the protection portion is fitted on the
outer periphery of the spiral projection portion. The same tape as
the aforesaid tape 31 is wound around the potion between the end
portion of the main body portion 4 and the outer periphery of the
joint member 32 to thereby integrate them and seal the gap
therebetween.
[0046] FIGS. 11 and 12 show another embodiment of the invention,
wherein a conduit opening member 3 is inserted into a through hole
41 which is formed in a side wall 30 of a hand hole in advance or
formed at the construction site and then attached thereto.
[0047] The conduit opening member 3 is arranged in a manner that
one halt thereof with respect to a step portion 42 formed at the
intermediate portion of the conduit opening member along the
longitudinal direction thereof is formed as a corrugated tube
portion 43 having a plurality of annular projection portions on the
outer periphery thereof and the other half thereof is formed as a
straight tube portion 44. A bellmouth 9 is integrally formed at the
tip end of the corrugated tube portion 43. An annular flange 45 is
formed at a portion on the inner peripheral surface almost
corresponding to the step portion 42 The conduit opening member is
formed as a packing housing portion 13 on the straight tube portion
44 side with respect to the flange 45. A female screw 46 is formed
on the inner periphery of the straight tube portion 44 serving as
the coupling side to the protection tube 1. A male screw 47 formed
on the outer periphery of the tip end portion of an engaging member
15 is meshed with the female screw 46 so that the protection tube
can be detachable from the conduit opening member. In this case,
the outer periphery of the potion 44 is made substantially on the
same surface as that of the engaging member 15. A hill-shaped
engagement projection 19 is formed on the inner periphery of the
tip end portion on the male screw 47 side of the portion 15.
[0048] The configuration of a supporting ring 22 and a come-out
preventing member 24 is basically same as the aforesaid embodiment
and a projection 48 for pushing a sealing member 27 is formed at
the tip end portion of the come-out preventing member 24.
[0049] The conduit opening member 3 is inserted into the through
hole 41 from the inner side of the side wall 30 such that the
straight tube portion 44 side serves as the head. The tip end of
the bellmouth 9 has a diameter larger than the inner diameter of
the through hole 41 and protrudes to the inner side from the inner
wall surface of the side wall 30, Putty 49 is filled in a gap
between the outer periphery of the bellmouth 9 and the through hole
41 to seal the gap portion in a watertight manner. On the other
hand, the tip end of the conduit opening member 3 on the straight
tube portion 44 side protrudes outward from the side wall 30. Putty
49 is also filled in a gap between the through hole 41 and the
outer periphery on the end portion side of the conduit opening
member to seal the gap in the similar manner.
[0050] The method of attaching the come-out preventing members 24
and the sealing member 27 to the protection tube 1 and the method
of performing the coupling and removal between the protection tube
1 and the conduit opening member 3 are same as the aforesaid
embodiment.
[0051] As a still another embodiment, a joint tube for jointing a
pair of protection tubes 1, 1 etc. may be used in place of the
conduit opening member 3. In this case, in FIG. 11, when the joint
tube is formed in such a manner that the right side portion of the
conduit opening member 3 with respect to the step portion 42 is
also formed at the left side in a mirror reversed manner, the
protection tubes 1, 1 respectively having the packing 27 and the
come-out preventing members 24 can be inserted into the joint tube
from the both sides and coupled to each other.
[0052] While there has been described in connection with the
preferred embodiment of the invention, it will be obvious to those
skilled in the art that various changes and modifications may be
made therein without departing from the invention, and it is aimed,
therefore, to cover in the appended claim all such changes and
modifications as fall within the true spirit and scope of the
invention.
[0053] As described above, according to the invention, since the
first tube member can be coupled to the second tube member by
merely performing one-touch operation of pushing the first tube
member to the second tube member in the state where the come-out
preventing member is attached to the tip end of the first tube
member, the invention is advantageous in that the coupling
procedure can-be attained simply in a short time. In particular,
when the second tube member is used as the conduit opening member
to be buried in the side wall of a hand hole and the first tube
member is used as the protection tube for a cable to be buried
within the ground such as an electric wire cable, the coupling
procedure of the protection tube to the hand hole can be simplified
greatly as compared with the conventional coupling structure.
[0054] According to the invention, since the engaging member
engaging the come-out preventing member can be separated from the
second tube member, the first tube member can be removed from the
second tube member by separating the engaging member. Thus, the
invention is advantageous in that the coupling procedure executed
again after the occurrence of failure in the coupled structure or
the maintenance procedure can be performed easily.
[0055] Further, according to the invention, since the packing is
attached to the tip end of the first tube member, the coupling
structure of the invention is excellent in watertightness and
suitable for the coupling member for a tube for a hand hole.
[0056] In addition, according to the invention, since the tip end
of the come-out preventing member abuts against the end surface of
the packing to thereby support the packing so as not to move to the
rear portion side thereof along the pushing direction, there does
not occur such a problem that the packing moves upon the pushing
operation to thereby degrade the watertightness.
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