TECHNICAL FIELD OF INVENTION
[0001] The present invention relates to the production technic of concrete blocks, or voussoirs,
which are used, in particular, in the construction of road or railway tunnels, hydraulic
tunnels and the like.
[0002] Concrete blocks are put in reciprocal contact and have to be provided with elastic
gaskets which ensure a perfect sealing of their relative surfaces against any possible
seepage by external agents, in particular water.
STATE OF THE ART
[0003] The main technical problem to face in carrying out concrete blocks, which is scope
of the invention, is represented in that the elastic gaskets are subjected not only
to compression but also to sliding, so that they could get out from their seats accomplished
in the concrete blocks, and consequently they do not ensure the necessary sealing
and cause dangerous leakages. Moreover, the ejection of the gasket from its seat prevents
the right reciprocal coupling of the blocks. Particularly, said risk occurs in relation
to the keystone when the gasket is not securely arranged.
[0004] To solve said problem, special glues are used which are spread on the surfaces of
the concrete block seats in order to make the relevant gaskets adhering. This operation
is particularly delicate and is very challenging because the layer of glue has to
be as uniform and homogeneous as possible. However, said result is rarely achieved,
even if the task is entrusted to specialized personnel that work by skill, thoroughness
and accuracy.
[0005] Further, concrete blocks are normally provided with irregular surfaces, with relieves
and cavities having dimension higher than 1 mm, and are undoubtedly covered in dust.
Then, in order to ensure a good adhesion of the glue, it is also necessary to provide
with a previous cleaning of the surfaces, so that working becomes complicated and
relevant cost and time increase. Cavities and relieves must be carefully repaired
by using suitable products and in any case the restored blocks may be glued only after
a complete cure of the products used for the repair.
[0006] A different solution was proposed in the patent application
WO 99/54593.
[0007] The device disclosed in said patent application requires that the gaskets have to
be positioned in their seat within the formwork during the casting of concrete blocks
by using vacuum equipment which operates through holes passing through the formworks
to vacuum seal the gaskets.
[0008] Therefore, the gasket remains fastened to the concrete without the need to use glue.
Gaskets show a profile conjugate with that of their relevant seats into the concrete
blocks, so that the mutual fastening is ensured.
[0009] Such a solution, however, requires installation and use of auxiliary means not much
suitable in a building site. Moreover, it is necessary to modify substantially the
production of the formworks, by making them worse with the requested holes, by creating
cavities and connections with a complex system of conduits to the vacuum apparatus.
[0010] A further drawback of the above solution disclosed in the mentioned patent application
is represented in that the gaskets show profiles which are different in linear parts
and in corner parts, respectively. For said reasons, this type of gaskets, which are
named fastened contrary to those named glued, are used only as an experiment, up to
now.
[0011] The patent application
WO 01/53657 discloses a system for producing concrete blocks to be used for construction of tunnels;
said blocks are provided with sealing elements in elastomeric material, which remain
mechanically fastened into concrete after their extraction from the formwork.
[0012] To satisfy the two opposing conditions of a secure fastening into the concrete block
and of an easy extraction from the formwork, the sealing elements have a particular
section (Fig. 3), comprising two feet having inclined and asymmetric profiles, merged
into the concrete, and sides with a profile having a double opposite inclination,
so that they may couple with a corresponding profile of the formwork. This solution,
just thanks to the particular profile, may produce undesired detachments of the gasket
from the formwork during the complicated steps for the prearrangement to the concrete
casting, due to possible crashes against other components of the block which are simultaneously
introduced with the same gasket.
SUMMARY OF THE INVENTION
[0013] The present invention relates to a sealing device for sealing concrete blocks, which
makes use of a gasket of fastened type.
[0014] The invention relates further to a manufacturing method for the sealing device and
to its implementation.
[0015] A first object of the present invention is to carry out a sealing device of the mentioned
kind which ensures maintaining the gasket correctly positioned into its seat during
the manufacturing steps of the concrete block, without the need to use auxiliary means,
like vacuum apparatuses or similar.
[0016] Another object of the invention is to carry out a gasket having a profile which allows
the detachment from the formwork without jeopardizing the gasket positioning with
reference to the concrete block and without producing strains in the gasket itself.
[0017] Again, an object of the invention is to carry out a gasket easy to be replaced in
case of breaking, and allowing the recovery and reclaim of the concrete block.
[0018] A further object of the invention is to carry out a gasket having a profile regular
and uniform along its whole development.
[0019] Moreover, the gasket is formed in such a way to be easily and intuitively fastened
into the formwork and to be able to avoid seepages of cement mortar on its surfaces
intended to watertight, so that the gasket integrates into the formwork without problem.
[0020] These and other objects are achieved by the device according to the invention, whose
technical features are defined in the claims at the end of the present description.
[0021] Features and advantages of the invention will be apparent from the following description,
given by way of example not limiting, with reference to the enclosed drawings, wherein:
Figure 1 shows in section a device according to the invention;
Figure 2 shows in section a manufacturing system for the device according to the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0022] Figures 1 and 2 show in section the sealing device for sealing concrete block (10)
according to the invention and the relevant manufacturing system and setting up the
same.
[0023] The device comprises a sealing profile in elastomeric material, which shows a body
(11) having an essentially parallelepiped shape and provided with internal cavities
(12). Said cavities cooperate to make elastic and deformable the body (11), so that
it performs its function and allows and facilitates its fastening in a formwork (16),
which is used to manufacture the concrete block (10), and to ensure the perfect sealing
of the sealing profile after its setting up in the concrete block.
[0024] The main feature of the device according to the invention is represented in that
the body (11) is provided on each of its two lateral longitudinal surfaces with a
cavity (14) which engages a corresponding rib (15) formed in the formwork (16) in
correspondence to the contact surface between the formwork and the concrete block.
The cavities (14) of the body (11) show, along the contact surface between the formwork
and the concrete block, a slanting side (19) which is pressed against the corresponding
rib (15) so that it ensures the perfect sealing at the manufacturing step of the concrete
block.
[0025] Therefore, the cavities (14) are defined by the slanting side (19) and a tooth (20),
which extends parallel to the contact surface between the formwork and the concrete
block. The tooth (20) is opposite to the side (19) and is less extended than the side
(19). This solution allows to accomplish an one-way snap insertion of the corresponding
rib (15) of the formwork into the cavity (14) of the concrete block, contrary to the
operation of the sealing element according to the patent application
WO 01/53657, previously mentioned, wherein the coupling between the profiles of the sealing element
and of the formwork is of two-way kind.
[0026] Like this, a strong coupling between gasket and formwork is obtained, and it is counterbalanced
by the shape of the feet drowned into the concrete and designed in order to offer
a huge capacity of fastening for the gasket; as a result, detachments of the gasket
from the concrete are avoided during the extraction from the formwork.
[0027] Moreover, it should be noted that the cross section of the body (11) is symmetric
with respect of the central axis, orthogonal to the contact surfaces with the formwork
(16) and the concrete block (10).
[0028] The body (11) extends by at least a fastening foot (13) which is able to be drowned
into the concrete block (10); preferably, the body (11) is provided with two fastening
feet (13) which extend longitudinally to the body itself.
[0029] According to another feature of the invention, the fastening feet (13) of the body
(11) show, inn cross section, a shape having internal surfaces (17) which are slanting
and opposite so as relevant lateral extensions (18) which are orthogonal to the central
axis of the body (11).
[0030] The shape of the gasket, according to the invention, ensures a self-forming of the
seat into the concrete block, so that the gasket can cushion all forces due to the
hydraulic pressure which are applied laterally.
[0031] Further, the gasket according to the invention, having a profile symmetrical with
respect to its central axis, allows to keep a regular and uniform profile along its
whole development, so avoiding the need to vary the shape in the corner parts with
reference to the linear parts. As the gasket is fastened to the concrete, it is able
to bear and overcome better the forces acting in order to eject it from its seat.
[0032] Moreover, the gasket according to the invention, even if it is mechanically fastened
into the seat of the concrete block, can be got out in case of damage and substituted
by a suitable reclaimed gasket, so that the high damage for the removal of the whole
concrete block can be avoided.
[0033] At the end, the invention relates also to a manufacturing and setting up method for
the mentioned device. As represented in Figure 2, the gasket is fastened to the formwork
(16) by a simple mechanical insertion of the body (11) into the corresponding seat
formed in the formwork, and by engaging the cavities (14) of the gasket in the ribs
(15) of the formwork. Later on, the casting of the concrete block (10) is carried
out and the gasket is integrated within the same block, thanks to fastening the feet
(13) of the body (11) into the block (10). Finally, the formwork (16) is disengaged
from the gasket, which remains mechanically fastened to the concrete block (10). The
perfect sealing of the device is ensured both in the mounting step of the gasket to
the formwork and in the casting step of the concrete block, thanks to compression
of the slanting surfaces of the body (11) with respect to the corresponding surfaces
of the formwork and of the concrete block.
[0034] Then, the device according to the invention allows to produce concrete blocks (10)
provided with elastic gasket (11), which are installed by achieving between them connections
very strong and perfectly sealed. Said concrete blocks fulfill all the scopes previously
reported.
1. Sealing device of concrete blocks or voussoirs (10), formed by a profiled member made
of elastomeric material, having a substantially parallelepiped body (11) and provided
with internal cavities (12), said body extending with at least an anchoring foot (13)
able to be drowned into the concrete block, the sealing device being characterized in that the body (11) is provided on each two lateral longitudinal surfaces with a groove
(14) which engages a corresponding rib (15) made into a formwork (16), fitting for
shaping the concrete block, in relation to the contact surface between the formwork
and the concrete block.
2. Sealing device according to claim 1, characterized in that the grooves (14) are provided at level of the contact surface between the formwork
(16) and the concrete block (10), with a slanting side (19) which is pressed against
its corresponding rib (15) so that to ensure a complete sealing during the concrete
block manufacturing.
3. Sealing device according to claim 1, characterized in that the transversal section of the body (11) is symmetrical in respect of the central
axis, orthogonal to the contact surfaces with the formwork (16) and the concrete block
(10).
4. Sealing device according to claim 1, characterized in that the anchoring feet (13) of the body (11) show in transversal section a shape having
internal surfaces (17) which are slanting and opposing each other and have respective
lateral extensions (18) orthogonally oriented with respect to the central axis of
the body (11).
5. Manufacturing method of a sealing device of concrete blocks (10) according the preceding
claims, characterized in that the body (11) of the sealing device is fixed to the formwork (16) by means of a simple
mechanical insertion of the body (11) into its corresponding seat made in the formwork
(16), and by engaging the grooves (14) of the body with the ribs (15) of the formwork,
then the casting of the concrete block (10) is carried out and the sealing device
is integrated into the concrete block, by anchoring the feet (13) of the body (11)
into the concrete block (10), at last the formwork (16) is disengaged from the sealing
device leaving the last one mechanically fixed to the concrete block (10).