Note: Descriptions are shown in the official language in which they were submitted.
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PIPE JOINT FOR PREVENTING SEPARATION
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The present invention relates to pipe joints
chiefly for pipes of relatively small diameters, and more
particularly to a separation preventing pipe joint having
means provided outside a socket for preventing a spigot
from slipping off the socket.
Pipe joints for water supply pipelirles, etc.
include those wherein a pressing ring is pressed against
an annular packing provided between a packing seat on the
lQ inner periphery of the open end of a socket and the outer
periphery of a spigot to seal off the connection be~ween
the socket and the spigot. With joints of this type, the
spigot is likely to slip off the joint, for example when
the pipeline is installed in a soft ground or is subjected
to earthquake or when the joint is used for connecting
pipes at an angle. Accordingly there is the need to
provide some means for preventing the slipping off.
U.S~ patent 4,092,036 issued May 30, 1978 to
Toshiyuki Sato, et al discloses a separation preventing
pipe joint of the type wherein an annular packing is
provided between the outer periphery of a spigot and a
packing sea~ formed on the inner periphery of the end of
a socket. The joint comprises a pressing ring bolted
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-to a,n ou-ter f]an~e a-t the ~ocket end, ~urroundin~ -the
spi~o-t ou-l,er periphery ou-t~i-3e the socke-t and havin~ one
end pres~ed a.~,~ains-l. the packin~; a plura.lit;y o-~ wed~es
providec] be-tween -I;he pre~in~ r:in~ and the spi~ot outer
periphery and slli-ta,bl;y arra~ed c:Lrcumferentiall,y -thereo~,
ea.ch o~'-the wed~es havin~ en~a~ing ed~es on i-t~ lnner
~ur:~ace; and tap 'bolt~ extendin.~ -throu~h the pre~in~
rin~ a,t csllitable por-ti.ons along it~ circum:Ference for
pressin~ the wed~es Erom ou-tside a~ain~t the spl~o-t oul,er
periphery~ Since the means f'or preventin~.the spi~ot from
~lippint~ ofY, namely separa.-tion preventin~ mean~, is
di.~posed outsi.cle th.e ~ocket, -the pipe ~joint is easier -to
assemble and prevents separa.tion more ef-fec-ti.vel,y 'by -the
a.ction of -the wed~es than those in which the separa-tion
preventin~ means is provided within the socket. 'However,
because the wed~e~ a.re separate and independent of one
another, the di~closed aoint i~ s-till c~nbersome -to
assemble and manu.fac-ture. ~'urther because the spi~o-t
outer periphery remains par-tially ou-t of con-tact wi-th
the wed~e~ and also because all the tap bolts are n.o-t
uni~orm in ~astening force, the spi~ot ou-ter periphery
i5 ~ub~ec-ted to uneven pressure. Especially when the tap
bol-ts are ti~htened up stron~ly to prevent separation
e-ffectively, more unevsn pressure will resul-t. I~ the
pipe i~ lined with cement, crack~ will then develop in
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-I;he l.ining. In -the case -where the spi~oti is to slip off,
-the wedges exert ~rea,ter ~ressure on the spi~ot ou-ter
peripher~. ~hus -l,he inevi.-table uneven distri.bution of
nressin~ forces even-tual.ly leEId3 -to -the likellhood tha,t
-the linl.n~ w~l.l separate o:F'f' ]oca:l,ly.
In vi.ew of -these problems, -the ob~ject o-f -the
p-resen-t inven-t:lon i.s to provide a ~epara,-ti.on preventin~
pipe ~oi.nt wh.ich ha.s mearl.s ~rovi.ded outslde a ~ocke-t :f'or
prevent-i.ng a. spi~o-t -~rom sl,ipping, o~-F the socket.and which
is ea.s;y to assemble and ca,pab].e of reliabl.y preventing
separa.tion without en-tai].in~ ob~ecti.ons such a.e crackin~
or separa-tion of the cement lining on the inner periphery
of the spi~ot.
rrO fulfill -this obaect, the present invention
provides a pipe aoint *or preventin~ separation wherein
an annular packing is provided between a paclrin~ seat
formed on -the inner periphery of a. socket and the outer
periphery of a spigot. The pipe ~oint comprises a. holdin~
member connectable -to an annular outer flange formed at
-the end of the socke-t and surroundin~ the spi~ot outer
periphery ou-tside the socket, the holding member bein~
annular or bein~ adapted to form an annular sha.pe, the
holdin~ member being provided on its inner periphery with
a tapered surface h.avi.ng an increasing diameter toward
the 30cket; a ~topper in the form of a rin~ divided at
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one ~or-t-lon and provided wi.-th an ou-ter peripheral tapered
sur~ace having an increa.sing diameter toward the socket
a.nd with en~agin.~ edge mea.ns in a plurality o~ circum~er-
en-tia.l rows on its i.nner periphery, the stopper being
in-terposed be-tween -the inner periphera]. tapered sur~ace
o~ the ho]ding member and the spigo-t outer periphery; and
tap 'bol-ts extending throu~h -the holding member at sui.table
por-tions a].ong i-ts circum:ference -~or pressing the stopper
~rom outside against -the s~igo-t outer peripher.y7 each o-P
-the tap bolts having a :~orward end face parallel -to -the
outer periphera]. tapered sur~ace o-~ the stopper.
According to -the construction described above,
the stopper is in the ~orm o~ a ring divided a-t one portion
~i~e. having circum~erentially opposed ends), so -tha.t -the
aoint is easy to assemble, while the spigot will not be
sub~ec-ted to uneven pressllre even if the tap bol-ts are
tigh-tened up strongly u.nl.ike -the conventional ~joint. ',rhis
eliminates problems, such as separa-tion of the lining.
~urther the uni~orm engagement o~ the engaging edge means
with the spigot outer periphery accomplish.ed by tightenin~
up the tap 'bolts strong],y can be ef~ec-ted more tightly by
the stopper which exerts a wedging action when the spi~ot
is to slip off. Within the limits o~ the strength o-~ the
holding member, therefore, it is almost unlikely tha-t the
spi.got wi].l separate -~rom the socket.
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Accordin~ -to an embodi.men-t of -the invention,
-the packlng sea-t is f'ormed on the inner periphery of' the
socket end, and. the holding member is an annular pressing
ring connec-ted a-t sui-table portions along it~ circumf'erence
-to -the ou-ter Elange a-t 1,he socke-t end by fastening members,
whereby the end. of' the p:ressing ring opposed to -the socket
is pressed against the packing-
According to anoth.er embodiment of`-the invention,
-the pacl{ing sea.t :i.s posi-ti.oned at a dis-tance ~rom -the open
encl f'ace o.~' th.e socket, and -the ho:Lding member comprises
a pl~lrality of circular arc housings connected -together in
-the ~'orm of' a.n annular ring by bo]..-ts and each having a
hook portion engageable wi-th -the outer flange at -the
socket end.
Various f'eatures and advantages of' the present
invention will become apparent from the Eollowing d.escrip-
-tion of embodiments given wi-th ref'erence to -the accompany-
i.ng drawings, in whic.h:
Fig. 1 is a side elevation in longitudinal
section showing a pipe join-t according to a first embodi-
ment o:E the invention;
~ig. 2 i~ a fron-t view showing a stopper;
l'ig. 3 is a view in section taken along -the
line III-III in li`ig. 2;
l~'ig, 4 is a front view showing a modiEication
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Or -the stop-perp
11'i.~. 5 is a view in sec-tion -taken along the
line V-V in 1~'ig. 4;
li'ig, 6 i5 a s.ide eleva-tion in longi-tudinal
section showing a second. embodi.men-t of the inven-tion;
L'\ig. 7 is a view in section taken along the
line VII VII i:n :L;`ig. 6;
~ 'ig. 8 is a view slmi.:l.ar -to -~'ig. 7 and showing
a mod.if.'ication of -the second embocliment as used for
d.iametrically large pipes9 and
Ii'.ig. 9 ls a ~ragmen-tary pla.n view o:E the sa.me~
With reference to :~ig. 1, two pipes 1 are
provided with a cement lin.ing la. One of -the pipes has
a spigo-t 2, which is inser-ted into the socket 3 of the
o-ther pipe for connection. An annular packil~g 4 made of
rubber or the like is interposed between -the outer perlphery
of the spigot 2 and a tapered -pac~ing seat 5 formed on the
inner periphery of the open end of the socket 3. A press-
ing ring 6 for pressing the packing 4 surrounds the spigot
2 outside the socket 3. The pressing ring 6 is fastened,
at portions (e.g. six por-tions) equidistantly spaced apar-t
circumferentially thereof, -to an outer flange 8 at the end
of the socket 3 by fastening members 79 such as bolts, nuts,
etc. The ring 6 has a pressing end 6a projecting toward
the socket 3 ~or pressing the packing 4 into intimate
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contact wi.th -the -two pipes l. T.he -pipe jolnt thus
cons-truc-ted connec-ts the spigot 2 a.nd the socket 3 toge-t.her
water-tightly.
~he presslng ring 6 has on its inner periphery
a -tapered surface 9 having an increasing di~meter toward
the socket 3 an~ def.ining a circumf'erentially con-tinuous
annul.ar recess 10 -to :~`orm a s-tepped portion between the
pressing end 6a and -the other end of` the ri.ng 6. .L~`itted
l.n t,he recess lO around -the outer periphery o~ the spigot
2 is a stopper 11 whioh is an integral ring divided at one
por-tion as shown in ~'igs. 2 and 4. '~he stopper 11 has an
outer peripheral su-rface 12 -tapered in conformi-ty with
-the tapered surface 9 ancL is provided on its inner
periphery wi-th a pl-ura]ity of engaging ed.ges 13 each
extending in the form o~ a ridge. The engaging edge 13
extends continuously circumferentially of thestopper as
seen in l~ig. 3. Alterna-tively engaging edges may be f`ormed
discretly circumferentially of the s-topper ll at a specified.
spacing as shown in Fig. 5. In either case~ it is
desirable -to form the engaging edges 13 in two rows at
axially opposite ends of -the stopper ll to prevent the
spigot from slipping of~ effec-tively. Between -the portions
of the pres~ing ring 6 fastened by the fastening members
79 tap bolts 14 are screwed in and extend through the ring
6 approximately perpendicular to the tapered surface 12 of
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-the s-topper 11. When tigh-tened up, the -tap bol-ts 14
press -t.he stopper 11 from outside against the spigo-t 2.
rl~he ta-p bol-t 14 has a .f`orward end face parallel to the
tapered s-urface 12 of the s-topper 11.
If`-the spigo-t 2 a~ts -to slip off :t'rom -the socl~et
3 to whlch it is connected by -the joint of'-the above
cons-truction, -the s-topper 11 pressed against the ou-ter
periphery o:~ the spigot 2 i.s moved by -the actlon of the
spigo-t 2 away from t.he socket 3 a1ong the forward end f'aces
o O:e the -tap bolts 14 and th.e tapered inner peripheral
surface o:f' the pressing ring 6. Consequently the .stopper,
acting like a wedge, is f'orcibly cons-tricted diametrically,
with -the result tha.t the engaging edges 13 on its inner
periphery are pressed agains-t the outer periphery of the
spigot 2 under increased pressure to bite into the periphery,
whereby the spigo-t 2 is prevented from slipping off, It
may appear that the tap bolts 14, when tightened up, will
separate the tapered surface 12 of` the stopper 11 from the
tapered surface 9 of` the pressing ring 6, but an effec-tive
pressure can be obtained actually merel~ by causing the
ends of` the bolts 14 to project sligh-tly from the tapered
surface 9, so -tha-t the taperes surfaces 9 and 12 can be
consid.ered to be substantially f'lush with each other.
~'urther at the locations where the tap bolts 14 are not
in pressing contact with the stopper 11, contact is assured
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between -the taperes surfaces 9 and 12. Thus the stopper
11. produces a wedging effect oveY -the entire periphery
thereof'.
~ specially beca-use the s-topper 11 is an lnte-
gral ring which is divided at one port.ion, the pressure
-to be exerted by the sto~pper 11 when the -tap bolts 14 are
tightened up .is subs-tantially uniform over the entire
circum~'eren-tial :Length of` the stopper, wh.ile i~ the spi.go-t
acts to slip of`f as above, -the s-topper 11 is diame-trically
constric-ted in i.-ts entire-ty and pressed against the spigo-t
as i.f constrictlng -the spigo-t. Accordingly -the pressure
and therefore the engaging action, namely s-topper action,
by the biting o~` the edges 13 exer-ted on the spigot are
approximately uniform over the en.-tire periphery of -the
spigot. This enables the stopper 11 to prevent separa-tion
very e~:fectively without the likelihood involved in the
convenlional join-t -that the spigot will be subjected -to
uneven pressure, ~or example, due to uneven fastening force.
I'hus -the present joint achieves an outstanding separation
preventing e~fect. Additionally because the stopper 11 in
-the ~orm of a divided bu-t integral ring will not exert a
high pressure local.ly on the spigot 2, the cemen-t lining
la is free of cracking or separation.
The stopper 11 which is a divided but integral
ring has another advantage that it is easy to ins-tall and
and make.
~ `igs. 6 and 7 show a second embodiment of the
inven-tion~ in which. the same parts as included in the first
embodiment are referred to by -the same corresponding
reference numerals. Such parts wlll not be described.
As shown in ~`ig. 6, this embodiment has a pack.i.ng
seat 5 positioned at a d.istance from the end face of` the
socket 3 and an annular projecliion 15 for hold.:ing an annular
packing 4 in position. A Ktopper ll is provided with a
holding member comprising two semicircular housings 6'
each having a connec-ting :f'lange 16 a-t each end and connected
together in an annular f'orm by bolts 17 and nuts 18. ~he
housing 6' has a hook portion 6a' which is engaged wi-th
the outer flange 8 of' the socket 3, whereby the housing
can be installed in place. The housing 6' is partly cut
out as at 19 where the housing interferes with tap bolts
14.
When the joint is used for pipes 1 of large
diame-ter, an increased number of tap bolts 14 are used as
seen in ~igS 4 8 and 9. Additional bolts 17l and nuts 18'
are employed for f`astening the connecting flanges 16
together tightly to prevent separation of the housings 6'
when the spigot 2 acts to slip of'f.
~he second embodiment prevents separation on the
same princip:Le as the first embodiment.
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