Connecting tubular body for handhole or manhole, block body for the tubular body, and handhole or handhole structure

A synthetic resin tubular body is fitted into the pipe connecting hole of a handhole when used. The cut edge face at one open end side of the tubular body having square walls in cross section and circular walls in cross section which are alternately disposed in its axial direction is the boundary portion between a side wall portion forming the square wall in cross section and a peripheral wall portion forming the square wall in cross section, and is cut in the boundary portion on the side apart from the open end side or in the proximity thereof. The length of the tubular body is set greater than the wall thickness of the handhole. In addition to the tubular body, a block body for the tubular body is formed with square and circular recessed portions conforming to the outer peripheral face of the open end side portion of the tubular body. Further, a handhole is such that the cut edge face of the tubular body and the inner wall surface of the handhole are arranged substantially on the same plane, and the other end side portion of the tubular body being projected outside the handhole, and besides the tubular body or the block body is watertightly fixed by a curing filler such as cement mortar or gelation resin filled in the pipe connecting hole.

BACKGROUND OF THE INVENTION 
The present invention relates to a handhole, a manhole or the like for use 
as an electric wire junction when an underground conduit line is formed 
for an electric wire, and to a tubular body to be connected to such a 
handhole or a manhole. 
Conventionally, in order to form an electric wire conduit line by coupling 
a tubular body to an electric wire junction such as a handhole, a manhole 
or the like of the sort mentioned above (hereinafter generally referred to 
as a handhole), it has been arranged that a tapered tubular member called 
a bell mouth separately formed is inserted in and coupled to the opening 
of the tubular body so as to use the bell mouth as a member forming the 
end of the opening of the tubular body. 
The operation of passing the electric wire through the tubular body has 
been impossible to perform smoothly unless the bell mouth is inserted in 
and coupled to the opening of the tubular body because the electric wire 
is brought into contact with the peripheral edge portion of the opening of 
the tubular body with the result that the resistance increases. Therefore, 
it has been necessary to prepare the bell mouth separately from the 
tubular body used to form the conduit line and transport the bell mouth to 
the jobsite. Moreover, the operation of coupling the bell mouth to the 
opening of the tubular body is necessitated in order that the bell mouth 
is not easily slipped off the opening thereof. 
SUMMARY OF THE INVENTION 
An object of the present invention is to solve the problems developed from 
means for forming a conduit line using such a conventional bell mouth as 
described above, and to provide a tubular body which doesn't need to use a 
bell mouth, a handhole coupled with tubular bodies in its opening by using 
such a tubular body, and a block body capable of readily forming conduit 
lines with a predetermined distance for the handhole. 
A tubular body according to the present invention is fitted into the pipe 
connecting hole of a handhole when used, wherein the cut edge face on one 
open end side of a synthetic resin tubular body having square (in this 
specification, the term "square" includes also the meaning of 
"rectangular") walls in cross section and circular walls in cross section 
which are alternately disposed in its axial direction is the boundary 
portion between a side wall portion forming the square wall in cross 
section and a peripheral wall portion forming the square wall in cross 
section, and is cut in the boundary portion on the side apart from the 
open end side or in the proximity thereof, and wherein the length of the 
tubular body is set greater than the wall thickness of the handhole. 
A block body for the tubular body has fitting recessed portions formed of 
alternately and axially disposed square and circular recessed portions 22 
and 23 conforming to the outer peripheral face of the open end side 
portion of the tubular body, and the block body is constituted by two unit 
block bodies split in the circumferential direction of the recessed 
portions. 
A handhole comprises a connecting tubular body constructed such that the 
cut edge face on one open end side of a synthetic resin tubular body 
having square walls in cross section and circular walls in cross section 
which are alternately disposed in its axial direction is the boundary 
portion between a side wall portion forming the square wall in cross 
section and a peripheral wall portion forming the square wall in cross 
section, the tubular body being cut in the boundary portion on the side 
apart from the open end side or in the proximity thereof; the cut edge 
face and the inner wall surface of the handhole are arranged substantially 
on the same plane, the other end side portion of the tubular body being 
projected outside the handhole; and the outer peripheral face of the tube 
wall continuous to the cut edge face is watertightly fixed in the pipe 
connecting hole of the handhole, the pipe connecting hole being filled up 
with a curing filler such as cement mortar or gelation resin. 
In order to practice the invention thus constituted, that is, the invention 
in the form of the aforesaid tubular body, for example, the cut edge face 
of a tubular body and one side face of a block body are arranged 
substantially on the same plane, and the other end side portion of the 
tubular body is projected outward from the other side face of the block 
body, so that the block body is fixed to the tubular body. In this case, 
the block body may be integrally secured to the tubular body, or two 
split-type block bodies separately formed may be used for putting the 
tubular body therebetween. Moreover, the block body may be so structured 
as to form a plurality of parallel coupling holes for use in coupling 
together a plurality of parallel tubular bodies. 
When the aforesaid handhole is practiced, the tubular body 1 is constructed 
such that the cut edge face on one open end side of the synthetic resin 
tubular body having square walls in cross section and circular walls in 
cross section which are alternately disposed in its axial direction is the 
boundary portion between a side wall portion forming the square wall in 
cross section and a peripheral wall portion forming the square wall in 
cross section, and the boundary portion on the side apart from the open 
end side is cut. Further, the tubular body is fixed to the block body such 
that the cut edge face of the tubular body and one side face of the block 
body are arranged substantially on the same plane, and the other end side 
portion of the tubular body is projected outward from the other side face 
of the block body. Moreover, the cut edge face and the inner wall surface 
of the handhole are arranged substantially on the same plane, and the 
other end side portion of the tubular body is projected outside the 
handhole. The outer peripheral face of the block body is watertightly 
fixed in the pipe connecting hole of the handhole, the pipe connecting 
hole being filled up with a curing filler such as cement mortar or 
gelation resin.

DETAILED DESCRIPTION OF THE INVENTION 
The preferred embodiments of the present invention will be described in 
detail with reference to the drawings. FIGS. 1-6 illustrate a first 
embodiment of a tubular body of the present invention. FIG. 1 is a 
perspective view showing the overall configuration of the tubular body; 
FIG. 2 is a front view of the tubular body; FIGS. 3-4 show the edge faces 
thereof; FIG. 5 is a sectional view of the tubular body in FIG. 2; and 
FIG. 6 shows the tubular body in working mode. 
The tubular body 1 shown in FIGS. 1-5 is, as shown in FIG. 6, a synthetic 
resin tubular body to be fitted into the pipe connecting hole "h" of a 
handhole H or a manhole serving as an electric wire or a telephone line 
junction. The tubular body 1 has square walls 2 which are substantially 
square in cross section and circular walls 3 which are substantially round 
in cross section, both walls being alternately disposed in the axial 
direction of the tubular body. The cut edge face "b" on one open end "a" 
side (left-hand side in FIGS. 1-2) of the synthetic resin tubular body 1 
is the boundary portion between a side wall portion 4 forming the square 
wall 2 in cross section and a peripheral wall portion 2a forming the 
square wall 2 in cross section, and so structured as to be cut in the 
boundary portion 5 on the side apart from the open end "a" side. Further, 
the length of the tubular body 1 is, as shown in FIG. 6, set about three 
times as great as the wall thickness "t" of the handhole H. The cut part 
in this case may be a part tightly along the boundary portion 5 apart from 
the open end "a" side or where the cutting is carried out in a part from 
the part along the boundary portion up to the substantially intermediate 
portion in the axis direction of the tube in the peripheral wall portion 
2a of the square wall. 
In order to use such tubular body 1 as an electric wire conduit line, it is 
connected to the handhole H. One of the means of use is, as shown in FIG. 
6, to arrange the cut edge face "b" on the open end "a" side of the 
tubular body 1 and the inner wall surface "f" of the handhole H 
substantially on the same plane, and the other end side portion "c" of the 
tubular body 1 is projected outside the handhole H so as to dispose a 
portion on the open end "a" side continuous to the cut edge face "b" in 
the pipe connecting hole "h" of the handhole H. The gap between the outer 
peripheral face of the tubular body 1 and the inner peripheral face of the 
pipe connecting hole "h" of the handhole H is filled up with a curing 
filler M such as cement mortar and when the curing filler M is hardened, 
the tubular body 1 is watertightly secured to the handhole H. 
More specifically, as shown by an imaginary line of FIG. 6, another conduit 
line 1A is laid on the outer end side of the tubular body 1 in the 
direction in which the tubular body 1 is extended, and both conduit lines 
are coupled together by means of a connector 1B. In this way, a series of 
conduit lines is formed up to the next handhole. 
Figures to be subsequently described refer to other embodiments. Referring 
to FIG. 7, two tubular bodies 1, 1 are laterally disposed in parallel. The 
cut edge faces b, b of the respective two tubular bodies 1, 1, which are 
respectively structured as previously noted, and one side face 10f of the 
synthetic resin block body 10 which is substantially rectangular are 
arranged substantially on the same plane. The other end side portions c, c 
of the respective tubular bodies 1, 1 are projected outward from the other 
side face 10g of the block body 10, so that the block body 10 and the 
tubular bodies 1, 1 are combined together into one body. Although the 
tubular body 1 in this case is formed from two of them combined together, 
it may be formed from one or more than two of them. 
It is not necessarily essential to combine the tubular body 1 and the block 
body 10 together into one body but may also acceptable to employ, for 
example, a vertically split type block body 10 comprising unit block 
bodies 10a, 10b as shown in FIG. 8. In other words, the block body 10 has 
fitting recessed portions 21 resulting from alternately and axially 
disposing square recessed portion 22 and circular recessed portion 23, 
which conform to the outer peripheral face of the open end "a" side 
portion of the tubular body 1 to be coupled, between the opposite faces 
10c of the split block bodies 10a, 10b. Two rows of fitting recessed 
portions 21 are formed in parallel in this embodiment. With this block 
body 10, the tubular bodies 1, 1 are fitted in between the two split unit 
block bodies 10a, 10b. In this case, an adhesive may be used if the block 
body 10 and the tubular body 1 have to be tightly secured together. 
FIGS. 9-11 refer to cases where the tubular body 1 secured or fixed to the 
block body 10 as shown in FIGS. 7, 8 has been coupled to the handhole H; 
namely, FIG. 9 refers to a case where the width of the block body 10 is 
set substantially equal to the wall thickness of the handhole H; FIG. 10 
to a case where the width of the block body 10 is set narrower than the 
wall thickness of the handhole H; and FIG. 11 to a case where the width of 
the block body 10 is set greater than the wall thickness of the handhole 
H. Also in these cases, one side face 10f of the block body 10 made to 
substantially conform to the cut edge face "b" on the one open end "a" 
side of the tubular body 1 is arranged so that the side face 10f is 
positioned on the substantially same surface as the inner wall surface "f" 
of the handhole H, and the outer peripheral face of the block body 10 is 
watertightly fixed in the pipe connecting hole "h" of the handhole H even 
in these cases, the pipe connecting hole "h" being filled up with a curing 
filler M such as cement mortar or gelation resin. 
FIGS. 12-13 show still other embodiment. In each of these embodiments, 
there is shown one block body 10 which is used for laterally arranging and 
coupling three tubular bodies 1, 1, 1. As shown in FIG. 12, a long tubular 
body 1 is disposed in the central position, whereas a shorter tubular body 
1 is disposed on both sides of the long one. When extended conduit lines 
are respectively coupled to these tubular bodies, such a conduit line is 
first coupled to the central tubular body in order to prevent the work of 
coupling another conduit line to any one of the remaining tubular bodies 
from being interfered. As shown in FIG. 13, three tubular bodies 1, 1, 1 
different in length are employed and the longest one is placed in the 
uppermost position with shorter ones being situated downward in order, so 
that when the work of coupling conduit lines is done by an operator from 
below, the previously coupled conduit line is prevented from impeding the 
work of coupling the next conduit line thereunder. 
With respect to the length of the tubular body 1 according to the present 
invention, not only relatively short tubular bodies shown in the drawings 
but also any other longer one may directly be used. As the material of the 
tubular body 1, any other synthetic resin can be used in addition to 
preferably polyolefin resin such as polyethylene and polyvinyl chloride 
excellent in weather resistance. Further, the two unit blocks separated in 
the circumferential direction need not be divided from a place where the 
recessed portion is divided into two equal parts as shown in FIG. 8 but 
may be arranged otherwise as long as the tubular body 1 is clamped. A 
plurality of stages of tubular bodies may also be coupled together by 
stacking them. 
Although a description has been given of representative working embodiments 
according to the present invention, the invention is not limited to the 
exemplary structures but may be modified on condition that the aforesaid 
component requirements and objects thereof are achieved within the range 
of effects enumerated below. 
As is obvious from the description above, the tubular body according to the 
present invention is so structured as to have the square walls in cross 
section and circular walls in cross section alternately disposed, and the 
cut edge face of the tubular body at the side used to be coupled to a pipe 
connecting hole of the handhole is cut in just the boundary portion 
between a side wall of both side wall portions forming the square wall in 
cross section in the axial direction of the tube, which is apart from the 
open end, and a circumferential wall portion forming the square wall, or 
cut in the proximity thereof. Therefore, since the opening itself of the 
tubular body forms a guide body when an electric wire is passed 
therethrough and the circular wall portion in cross section contacts and 
supports the electric wire, the advantage is that the work of fitting the 
electric wire into the tubular body is extremely smoothly carried out with 
the least frictional resistance. Moreover, since no bell mouth is required 
to be formed separately, only the tubular body is required to be conveyed 
at the time of coupling work. Thus the work of fitting the bell mouth to 
the tubular body can be omitted. In addition, the tubular body it self can 
be extremely stably disposed in an excellent posture because of the 
presence of square walls in cross section. 
The block body according to the present invention has the fitting recessed 
portions resulting from alternately and axially disposing the square 
recessed portions and circular recessed portions, which conform to the 
outer peripheral face of the open end side portion of the tubular body, 
and is constituted by two unit block bodies divided in the circumferential 
direction. Thus the advantage is that the tubular body is made usable by 
fitting it into the recessed portion in the required place and that the 
tubular bodies can be positioned with a predetermined distance held among 
them by means of the block body stably in a fixed posture. 
Since the handhole according to the present invention is arranged so that 
the tubular body itself is watertightly secured in the pipe connecting 
hole of the handhole directly or via the block body with the curing filler 
such as cement mortar or gelation resin, there is no fear that a member 
such as the bell mouth falls down from the tubular body or becomes loose. 
Especially, since the electric wire can be directly inserted into and 
through the tubular body, and the tube diameter is free from local 
reduction due to the mounting of the bell mouth at the entrance and exit 
of the wire passageway, the effect of making usable a tubular body having 
an adequate diameter can be expected.