Note: Descriptions are shown in the official language in which they were submitted.
:113~;~3~
1 BACKGROUND OF THE INVENTION
Field of the Art
The present invention relates to a gasket of elastic
material, such as rubber or similar for use in forming a seal
between respective sealing surfaces of two members to be joined,
the gasket for installation purposes being attached to the
sealing surface of one of the members, and the sealing surfaces
of the members ~eing moved substantially parallel to each other
for squeezing the gasket therebetween.
In connection with the assembly of concrete basins and
other pipe-shaped products which are to be sealed by a gasket
of elastomeric material, it is necessary to cover the gasket or
one of the sealing surfaces with a lubricant for reducing the
friction ~etween the gasket and the joint member. This is of
special importance in the cases where limited forces are avail-
a~le for compression or where tolerances in the joint members
may easily lead to the occurrence of breakage therein due to
too high gasket pressure. However, the friction between rubber
and e.g. concrete is so high that such an installation neverthe-
20 ~ less involves large difficulties.
Prior Art Statement
There are previously known several gasket constructions
which can facilitate the installation, said gaskets offering a
satisfactory sealing. In U.S. Patent 4-,170,365
instructions are given for a gasket cross-section including a
core which is constructed from closely arranged lamellae which
during the installation are angularly shifted for thereby reducing
the height of the gasket, the elasticity of the rubber urging
to revert the lamellae to their vriginal position fQr thereby
effecting the necessary packing pressure. In connection with
113!~?;~
1 fairly smooth sealing surfaces such a known gasket functions
satisfactorily. If the sealing surfaces have, to the contrary,
a very rough surface, it i5 very difficult to have the sealing
surfaces slide along the ru~ber gasket.
Further, there are known structures seeking to eliminate
the sliding between concrete and rubber, and for example in US-
PS 3 510 140 there is suggested a gasket in which portions of
the gasket profile during the installation is folded, a lu~ricant
~eing provided ~etween the folded portions. During installation
the sliding will take place between the rubber surfaces of the
gasket rather than between rubber and concrete. Such a known
gasket structure functions fairly satisfactorily, but it suffers
for the disadvantage that the lubricant must be applied immedi-
ately prior to the installation, the lubricant otherwise being
apt to easily disappear during storage as well as being easily
contaminated on site.
In additon, although such a known gasket offers a
relatively easy installation of the members to be joined, it
suffers from the disadvantage that the finished installed members
may easily ~e separated since the gasket hardly offers any
resistance when the joint members are influenced by forces seaking
to urge them apart.
In SE-PS 78 00282-1 there is disclosed embodiments of
sealing rings comprising a substantially triangular main portion
and a relatively thin portion which from a point of connection
extends across a conical sliding surface on the triangular main
portion. Such a triangular main portion having a conical sliding
surface is unfavoura~le in connection with joints which are to
adopt large pressures, since only a minor portion of the core of
the gasket will ~e utilized for sealing purposes in its final
~1 3~
1 mounted position. Further, the patent specification only dis-
closes embodiments in which a covering portion extends from the
triangular core portion and together therewith define a pocket
open in the longitudinal direction, a fact which includes that
a predisposed lubricant will easily disappear due to evaporation
or washing off if the gasket is not transported and stored with
a special packaging.
SUMMARY OF THE INVENTION
The object of the present invention is to give instruc-
tions for a gasket which does not suffer from the a~ove-mentioned
disadvantages. More particularly, the invention provides a
gasket having such a structure that the applied lubricant is not
subjected to contamination, the lubricant not being able to dis-
appear by evaporation or otherwise.
The object is achieved in a gasket of the type stated
in the preamble, which according to the present invention is
characterized in that the gasket in combination comprises a
major portion or core adapted so as to be deformed during the
installation movement, the elasticity of the core material seeking
to revert the core to its original position for there~y effecting
a packing pressure, and a relatively thin gasket portion which
defines a closed jacket outside the very core, and the inner
surface of which is provided with a lubricant for during the
installation whilst sliding along the core, serving as a friction
reducing sliding jacket between the core and the sealing surface
which is displaced relative to the core.
Hereby is achieved a gasket which in advance has been
provided with a lubricant, said lubricant being sufficiently
covered to avoid the collection of dust and dirt on the sliding
surfaces of the gasket. Further the closed sliding jacket will
113~3;~:
1 involve a complete sealing off of the gasket portions provided
with a lubricant, thus avoiding evaporation or washing away of
the lubricant and a pollution of the environment thereby.
The thin sliding jacket may embrace a larger or lesser
portion of the core of the gasket, but it must be so dimensioned
that the total installation movement between the inner and the
outer sealing surface is transferred via the sliding jacket. If
the total inner surface of the sliding jacket as well as the
portion of the core embraced by the jacket is provided with a
lubricant, the installation friction may be very low.
A further development according to the invention is to
the effect that the closed jacket at the one end of the core is
provided with one or more intermediate portions disposed between
the core and the remaining jacket, and/or between remaining
jacket portions.
Such a jacket is especially favourable in those cases
in which a long relative movement ~etween the members to be joined
will occur during the installation. In connection with suitable
em~odiments of the intermediate portions the sliding length of
the jacket can be increased considerably.
Suitably portions of the sliding jacket may be imple-
mented as folds, foldings or similar, which during the install-
ation of the mem~ers to be joined, are pulled ahead continuously
in the direction of the installation.
However, it i5 to ~e understood that an intermediate
jacket portion can also be arranged in an inclined relation to
th~ core or a portion thereof. In that case the core will also
~e provided with a sloped surface, but this surface will not
define a sliding surface, but in contrary a braking surface, the
intermediate portion during installation being adapted to roll
1~3~
1 off the core. However, the remaining portion of the jacket
will during installation define a friction reducing means be-
tween the core and the sealing surface which is moved relative
to the gasket core.
To achieve a braking effect between an intermediate
jacket portion and the core the respective abutting surfaces can
be provided with furrows engaging each other.
The intermediate jacket portion may have the same
thickness as the remaining sliding jacket, but in many cases when
the gasket is in its final installed position, it is desira~le
to have a higher gasket compression pressure than the compression
pressure which the gasket should offer during the displacement
of the members to be joined, and especially at the start of the
installation. In such cases the intermediate jacket portion and
the passage from the core to the sliding jacket may be designed
wit~ a larger thickness than the remaining sliding jacket,
preferably a thickness which increases towards the attachment
point of the core portion.
During the last part of the assembly of the pipes or
t~e joint members the thicker portion will be pulled in between
the core portion and the opposite sealing surface, so that the
active sealing volume of the gasket will increase.
An embodiment of an intermediate jacket portion may be
to the effect that it together with the adjoining core portion
define a drop-shaped track. When the members to be joined are
~rought in position and the sliding jacket is displaced to its
final position, the drop-shaped track will form a concave gasket
end surface aiding in a further sealing effect between the joint
members when a fluidum pressure influences the said end surfaces.
It is to be understood that the sliding jacket may be
1139;~
1 attacked to the core either by being formed integrally with the
jacket for example by extrusion or moulding, or by other suit-
able attachment methods. For Example, the jacket may at one
attachment point be formed integrally with the core, whereas at
a second attachment point it may be glued or welded to the core.
Possibly the jacket may be attached to the core by a snap lock
formed for example by opposite dovetail slot and dovetail means,
etc.
The gasket according to the invention may easily be
manufactured by extruding long strings to be cut in suitable
lengths and thereafter possibly welded or vulcanized at the ends
thereof from forming suitably sized rings. Possibly the gasket
may be moulded in forms. The method of manufacturing the gasket
depends on the structure of the gasket as well as the shape of
the outer sliding jacket.
The gasket according to the invention may be used in
all joints wherein the sealing surfaces are to be displaced su~-
stantially parallel to each other. Aside from having an annular
shape the gasket may also be used in arbitrarily cut lengths,
for example as hatchway gaskets.
In the following the invention will be further described,
reference being had to the drawing, which illustrates various
embodiments of the gasket according to the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. la illustrates a cross-section through a first
embodiment of the gasket according to the invention.
Fig. lb illustrates a cross-section through the gasket
of Fig. la in installed position.
Fig. 2a illustrates a section through a second embodiment
of the gasket according to the invention.
--6--
lt`~!~3~
1 Fig. 2b illustrates a section through the gasket of
Fig. 2a in installed position.
Fig. 3a illustrates a section through a third embodiment
of the gasket according to the invention.
Fig. 3b illustrates the gasket of Fig. 3a in installed
position.
Fig. 4 illustrates a cross-section through another
embodiment of the gasket according to the invention, provided on
the spigot end of a joint member.
Fig. 5 is a section similar to Fig. 4 and illustrates
the gasket with assembled joint members.
Fig. 6 is a cross-section through a variant of the
em~odiment illustrated in Figs. 4 and 5, provided in a slot in
the spigot end of a joint member.
Fig. 7 is a section through a further variant of the
embodiment illustrated in Figs. 4 and 5.
Fig. 8 illustrates a cross-section through a further -
em~odiment of the gasket according to the invention.
Fig. 9 is a cross-section throughstillanother embodiment
of the gasket according to the invention.
DESCRIPT~ION OF PREFERRED EMBODIMENTS
In Fig. la, which is a section through a first embodiment
of t~e gasket according to the invention, 1' designates the very
gasket, and 1 the major portion or core of the gasket, whereas
2 designates a thin gasket portion defining a closed jacket
outside the very core 1. Together with the core 1 the jacket 2
define a hollow cham~er 3, the walls of which are coated with a
lu~ricant, so that the sliding jacket 2 during installation of
the joint members to be sealed by the gasket, may easily slide
along the core 1 and thus facilitate the movement between the
-7-
il3~
1 sealing surfaces of the joint members.
In Fig. lb, 4 designates a segment of a cross-section
throught the spigot end of a first pipe- or ring-shaped joint
member, whereas 5 designates a segment of a section through the
socket end of a second pipe- or ring-shaped joint member to be
put down onto the joint member 4. The spigot end or the joint
member 4, which for example may be a concrete pipe, a basin ring
or similar, is provided with a vertical sealing portion or
sealing surface 6, which at the top merges into a horizontal
abutment surface 7, and which at the bottom via a step 8 merges
into an intermediate portion 9 having a somewhat larger diameter
than the portion 4. Via a curved transition portion 10 the
intermediate portion 9 merges into a su~stantially horizontal
abutment portion 11, which along its peripheral edge joins the
outer wall 12 of the spigot end. In Fig lb, 13 designates the
inner wall of the joint member 4.
The second joint member 5, which for example may be a
concrete pipe having a socket end to ~e fitted onto the spigot
end of the joint member 4, comprises an outer wall 12 and an inner
wall 14. At its lower end the latter merges into a first horizon-
tal abutment portion 15 which via a curved transition portion 16merges into a vertical sliding portion 17, which in turn merges
into a second horizontal abutment portion 18. This, in turn,
merges into the outer edge of the above-mentioned outer wall 12.
The gasket 1' which is illustrated in dismounted
position in Fig. la, is threaded onto the area of the vertical
sealing portion 6 and the step 8 of the spigot end 4. The gasket
core 1 is of a larger thickness t~an the gap to be sealed, i.e.
the gap ~etween the sealing surfaces 6 and 7 on the spigot end
4 and the socket end 5, respectively, so that in mounted position,
113~
1 i.e. with the socket end 5 threaded onto the spigot end 4, the
gasket will be in a compressed position between the sealing
surfaces 6, 17. Because a sliding jacket 2 has been provided on
the outside of the core 1, the mo~ement between the inner and the
outer sealing surface 6 and 7, respectively, will be transferred
via the jacket 2, so that the sliding will take place between the
sliding jacket 2 and the core 1. The total inner surface of the
sliding jacket 2 and the portion of the core 1 which it embraces,
is coated with a cover of lubricant, so that the friction during
installation ~ill be very small.
In Fig. la which illustrates a first embodiment of the
gasket according to the invention, the sliding jacket 2 embraces
a larger portion of the core 1 of the gasket, said jacket from
a first corner 19 of the core extending therealong to a second
corner 20 disposed approximately diametrically opposite to the
first corner 19. In the unmounted position of the gasket 1',
the sliding jacket 2 protrudes only a minor distance from the
first core corner 19, whereas from the second corner 20 it
protrudes a distance corresponding to the thickness of the core.
~ T~us, the length of the sliding jacket 2 will be large enough to
follow the relative movement between the spigot end 4 and the
socket end S when these are put in position during the instal-
lation procedure. As illustrated in Fig. lb, the sliding jacket
2 have, subsequent to the completion of the installation, slid
along the gasket core 1 in such a manner that it will then be in
contact with the gasket core 1 at the corner 20, whereas at the
second corner 19 it will form a surplus narrow hollow chamer 21.
Besides, the gasket core 1 of the gasket illustrated
in Figs. la and lb. is provided with a series of parallel lamellae
22a-22f, which during installation are angularly shifted so that
1~39;~3Z
1 the thickness of the gasket core 1 is reduced. The intrinsic
stiffness of the material of ~he gasket will, however, induce a
return resiliency of the lameallae 20a-20f, whereby the thickness
of the gasket and thereby the packing pressure will be apt to
ncrease .
It is to be understood that the relation ~etween width
and thickness of the lamellae may be varied within wide limits,
so that the resilient characteristic of the gasket during the
installation and the final packing pressure may ~e varied accor-
dingly.
An advantage of the gasket structure illustrated ih
Figs. la and lb is to the effect that due to the skew angle
which the lamellae 22a-22f take in their installed position, there
is obtained a large locking force between the spigot end 4 and
the socket end 5, because the lamellae have to ~e clenched or
deformed before turning over their neutral position. This force
is much larger than the force necessary for deflecting the
lamellae during installation.
This condition also influences the packing characteristics
of the gasket, since an inner or outer pressure will influence
the surfaces 7, 15 and 11, 18, respectively. If these surfaces
are shifted apart as a result of the pressure, the lamellae
22a-22f will ~e clenched, a fact which involves that the packing
pressure will increase.
In Figs. 2a and 2~ there is illustrated a second
embodiment of the gasket according to the invention, and this
gasket which is generally designated ~y 1", is provided with a
gasket core la having an outer cross-sectional shape corresponding
to the core 1 of Fig. la and having a sliding jacket 2a su~-
stantially corresponding to the jacket 2 of Fig. la. Differently
--10--
~i3~332
1 from the gasket of Figs. la and lb the sliding jacket 2a of Figs.2a and 2b is provided with two ridges 23, 24 on the jacket portion
25 extending from the corner 20a. In the mounted position of
the gasket 1", as this is illustrated in Fig. 2b, the two
ridges 23, 24 define an extra lip tightening against the sealing
surfaces 6 and 17 of the spigot end 4 and the socket end S,
respectively. In this case the core la is provided with a
plurality of circular channels 25' extending in the longitudinal
direction of the jacket and making the gasket easily compressable
during installation. After installation the circular channels
25' take an oval-shaped form, as this appears from Fig. 2b.
Also in the embodiment illustrated in Figs. 2a and 2~ the sliding
jacket 2b will transfer the relative movement between the socket
part 5 and the gasket core la on the spigot end 4, said jacket
in the final mounted position defining a narrow, hollow chamber
21' on the opposite side of the hollow cham~er 3' defined thereby
prior to the installation.
The gasket 1' has favoura~le sealing properties because
it resides compressed between the two sealing surfaces 6 and 17,
the concave jacket portions 25 between the ridges 23, 24 inducing
increased sealing effect as regards the inner pressure in the
spigot mem~er 4 and the socket member 5. An inner pressure
which is efféctive in the area of the curved end surface brought
a~out ~ the jacket portion 25, will press the ridges firmly
against the sealing surfaces, and the larger the inner pressure
is, the stronger the lip portions or ridges 23, 24 will ~e
pressed against the mentioned sealing surfaces.
In Figs. 3a and 3~ variants of the gasket discussed
in connection with Figs. la and lb are illustrated. In Fig. 3a
where the very gasket is designated ~y 1"', it comprises a core 1
113~3;~3;~
1 having a series of parallel lamellae 22a'-22f', as well as a
sliding jacket 2b having a basic shape corresponding to that
illustrated in Fig. la. In order to increase the locking effect
of the gasket in mounted position, the core lb and the sliding
jacket 2b are provided with saw-toothed furrows 27 and 28,
respectively, which slide past each other in the installation
direction, but effect a locking for the return movement. In Fig.
3b there is illustrated how the saw-toothed furrows 27 and 28
are in engagement with each other in the mounted position of the
gasket 1"'.
- For better filling of the pores and scratchings of the
sealing surfaces the gasket according to the invention may on
the outside ~e provided with longitudinally extending thin ribs
29, which penetrate into the irregularities of the sealing surfaces
6 and 17 of the spigot member 4 and the socket member 5,
respectively. In Fig. 3b the longitudinally extending ribs 29
have ~een deleted for the sake of survey.
In Fig. 4, which is a section through another embodi~ent
of the gasket according to the invention, 30 designates the very
gasket and 31 the main portion or core of the gasket, which may
be manufactured from a compact, but elastic material, as this is
illustrated in Fig. 4, but which, of course, may be manufactured
in different ways, for example with longitudinally extending
channels or slits. Around the main portion or the core 31 there
is provided a gasket portion 32 which compared to the core is a
thin portion and defines a closed jacket outside the very core 31.
Together with the core 31 the gasket portion or jacket 32 define
a hollow chamber 33, the walls of which are covered with a
lubricant, so that the sliding jacket 32 during the installation
o~ the joint members to be sealed by the gasket 30, may easily
1 13~3~
1 slide along a substantially vertical or weakly curved portion
34 of the core 31.
In Fig. 4 there is illustrated a fraction of the spigot
end of a first pipe- or ring-shap~d joint member 35 on which the
gasket 30 is disposed. In Fig. 4 there is further illustrated
a fraction of a section through the socket end of a second pipe-
or ring-shaped joint member 36 which is to be put down on the
joint member 35.
Prior to the assembly of the joint members 35 and 36,
the gasket 30 is threaded onto the spigot end of the joint member
35, the lower end surface 37 of the gasket resting on a step 38
provided on the spigot end of the joint member 35.
The gasket core 31 has a larger thickness than the gap
to be sealed, i.e. the gap between the sealing surfaces 35' , 36'
of the spigot end member 35 and the socket end member 36 respec-
tively, so as to be resting compressed between the sealing surfaces
in assembled position, i.e. with the socket member 36 threaded
onto the spigot member 35. Because of the sliding jacket 32
provided on the outside of the core 31, the movement between the
sealing surfaces of the joint mem~ers will be transferred via the
jacket 32, so that the sliding will take place between the sliding
jacket 32 and the core 31. The total inner surface of the sliding
jacket 32 and the portion of the core 31 embraced thereby, may
then be provided with a coat of lubricant, so that the friction
during installation will be very small.
In Fig. 4, which illustrates a special em~odiment of
the gasket according to the invention, the sliding jacket 32
embraces a larger part of the core 31 of the gasket, said jacket
from a first corner 38 of the core 31 extending therealong and
there~eyond for at the top to join a somewhat stiffer jacket
113g.~3~
1 portion 39 which is in contact with the sealing surface 35' of
the joint member 35. At its lower end the jacket portion 39
merges into an intermediate jacket portion 40, i.e. a portion
located between the core 31 and remaining jacket portions.
As illustrated in Fig. 4 the intermediate portion 40
is via an attachment point 41 attached to the core 31 at that
side which is opposite to the joint member 35, so that the
intermediate portion during installation of the two members 35
and 36, respectively, is turned about the attachment point 41
for thereby forming an extension of the jacket 32 in the direction
of the installation.
This extension of the sliding jacket is particularly
favourable in those cases where joint members which must be
moved a long distance relative to each other during the assembly
operation, are used. The intermediate portion of the sliding
jacket will then be able to increase the movement of the sliding
jacket in the direction of the installation, a distance corre-
sponding approximately to twice the thickness of the gasket core,
but this increase is of course depending on how the intermediate
portion is designed and the shape of the core in other respects.
Possibly, the intermediate portion or portions may be
designed with an undulated, folded or corrugated form which is
stretched or extended during the installation movement. How-
ever, it is to be observed that the intermediate portions should
not give the very gasket a shape which may be unstable when being
put in position on one of the joint members, i.e. it is to be
aimed for attaining a displacement of the sliding jacket which
gives a continuous pulling thereof in the direction of the
installation.
The intermediate portion 40 defines together with the
top portion 42 of the core 31 an approximately drop-shaped track
13.3~ 2
1 43, When the members 35, 36 which are to be joined, have ~een
brought in position as this is illustrated in Fig. 5 and the
sliding jacket 32 has been displaced to its final position, this
track will form a concave gasket end surface 44 aiding in a
further sealing effect between the joint members when a fluidum
pressure influences said surface.
To increase the locking effect of the gasket in the
assem~led position thereof the portion 34 of the core 31 as well
as the jacket por~ion 39 are provided with saw-toothed furrows
45 and 46, respectively, which slide over each other in the
direction of the installation, but have a locking effect in the
opposite direction. In Fig. 5 it is illustrated how the saw-
toothed furrows 45 and 46 will come into engagement with each
other in the assembled position of the gasket 30.
To improve the filling of pores and scratchings in the
sealing surfaces the gasket according to the invention may on
the outside be provided with longitudinal thin ribs penetrating
into the cavities of the sealing surfaces of the spigot member
35 and the socket member 36, respectively. In Figs, 4 and 5
such longitudinal outside ribs are deleted for the sake of survey.
In Fig. 6 there is illustrated a variant of the gasket
discussed in connection with Figs. 4 and 5, the gasket 30a in
Fig. 6 differ}ng from the gasket according to Figs. 4 and 5 by an
intermediate jacket portion 40a which together with the gasket
core 31aare adapted to fit into a slot 47 provided in the spigot
mem~er 35a. Due to the slot 47 in the member 35a this is given
a larger end diameter, and the socket end mem~er 36a will there-
fore enter the spigot end mem~er 35 with lesser play. However,
the manner in which the sliding jacket 32a is displaced during
the installation, will ~e similar to that of the gasket discussed
~13~?3i:
1 in connection with Figs. 4 and 5.
The intermediate portion 40a of Fig. 6 is given an
approximate zig-zag shape, but still defines together with the
top surface 42a of the core 31a a drop-shaped track 43a which in
final assembled position of the gasket 30a, defines a concave
gasket end surface similar to the surface 44 illustrated in Fig.
5.
In Fig. 7 there is illustrated a further variant of the
gasket discussed in connection with Figs. 4 and 5, the gasket 30b
of Fig. 7 being provided with a sliding jacket 32b which joins
the lower end surface of the gasket core 31b by a locking
mechanism generally designated by 48. The locking mechanism 48
comprises on the one hand a dovetail-shaped slot 4~ provided in
the lower end surface 37b of th core 31~, and on the other
hand a rib 50 provided on the sliding jacket and ~eing adapted to
fit snugly into the dovetail-slot 49.
It is to be understood that the sliding jacket may be
attached to the core in other manners than that illustrated in
the embodiment in Fig. 7. Of course, the sliding jacket may be
formed integrally with the core, but it may also either at the
one or both ends be attached to the core by gluing or welding
or similar. It is further to be understood that such agencies
for attaching the jacket to the core can also be used in connection
with other embodiments of the gasket according to the invention.
In Fig. 8 there is illustrated a further embodiment of
the gasket according to the invention, in which the very gasket
30 c comprises a su~stantially rectangular core 31c, comprising
a plurality of parallel slits or narrow slots 51. The inter-
mediate jacket portion 40c is here provided as a substantially
transversalLy extending top piece extending from the one top
-16-
11~
1 corner 52 of the core 31c and in the area of the second top
corner of the core merging into the remaining jacket 32c.
However, it is to be understood that the intermediate
jacket portion may have an inclination relative to the gasket
core or a portion thereof. Such an embodiment of a gasket
according to the invention is illustrated in Fig. 9, in which
the very gasket is designated by 30d, the core by 31d, and the
sliding jacket generally designated by 32d. The core 31d is
here provided with a plurality of slits 52, as well as a sub-
stantially vertical sliding portion 53 and an inclined furrowed
braking portion 54.
The sliding jacket 32d extends from a lower corner 55
of the core 31d along the sliding portion 53 of the core and
further along the inclined core portion 54 and ~eyond this,
whereafter it via a folding portion 55 is folded back between
the inclined braking portion 54 of the core and remaining portions
of the very jacket to join the core at the upper edge of the
sliding portion 53.
In the area in which the sliding jacket 32d extends
along the inclined braking surface 54 of the core 31d, the jacket
is similarly to the braking surface 54 provided with furrows
56 which engage opposite furrows 57 of the braking surface 54.
Thus, the intermediate portion 40d of the sliding jacket 32d
will during installation not slide along the furrowed braking
surface 54, ~ut roll off from the top of the surface 54, whereas
the remaining portion of the sliding jacket 32d slides along the
- substantially vertical sliding surface 53 of the core 31d.
Such a gasket having an inclined core portion, is
especially applicable in connection with ioint members which
aside from having an axiaL sealing surface, have an inclined
113~
1 sealing surface which merges into the axial sealing surface and
in assembled position of the joint members are adapted to be in
contact with the inclined core portion. The furrowed surface of
the inclined core portion 54 will in assembled position of the
joint members penetrate into the cavities of the inclined seal-
ing surface of a first joint member which is threaded onto the
joint member holding the gasket, whereas the intermediate portion
40d wîth its furrows 56 will penetrate into the cavities of the
axial sealing surface of the first joint member. The inter-
mediate jacket portion or portions discussed above may have the
same thickness as the rest of the sliding jacket, but in many
cases when the gasket is in its final assembled position, it may
be desired to have a higher gasket compression pressure than the
compression pressure provided by the gasket during the assembly
of the two mem~ers to be joined, and then especially at the
start of the assembly. In such cases an intermediate jacket
portion and the passage from the core to the sliding jacket may
be provided with a larger thickness than the rest of the sliding
jacket, preferably increasing towards the core portion attachment
point.
During the latter part of the assembly of the pipes
this thicker portion will ~e pulled in between the core portion
and the opposite sealing surface, so that the active sealing
volume of the gasket increases.
It is to be understood that the gasket according to the
invention may be used not only in connection with concrete pipes
and basins, but also for joint members of other material, for
example plastics, steel, iron, etc. It is further to be under-
stood that the gasket not necessarily has to form closed loops,
but can be used in arbitrarily cut lengths, for example assealing means in hatches etc.
-18-
1135~33~
1 It is further to be understood that the gasket does
not have to be mounted on the spigot end of the joint members
to be put together, but can also be mounted in a slot in a
joint socket.
-19-
