FIELD OF THE INVENTION

The present invention concerns a containing or closing valve, suitable to be associated with formworks used in making concrete articles, in particular, but not only, for lining tunnels or similar constructions.

The invention is applicable not only to metal formworks, but also those made of wood or its derivatives, multilayer formworks and mixed metal-wood formworks.

The invention also concerns formworks equipped with said valve.

BACKGROUND OF THE INVENTION

In the production of concrete articles, it is known to use formworks for containing the cast material which confer upon it the desired geometry.

It is known that formworks apparatuses that can have sizes that range from a few tens of centimeters up to and beyond about ten meters, and that they can be made of wood or metal or again of both wood and metal.

It is also known that formworks, especially the bigger ones, for example used to make infrastructures such as tunnels, bridges or roads, can comprise a metal support structure for a terminal containing wall, also known in the field as "shell".

The shell is the terminal part of the formworks, intended to come into contact with the concrete cast, and is configured to define in practice the geometric characteristics and sizes of the article to be made. The shell is also configured to support the stresses caused by the fresh concrete during casting.

The shell can be made either of metal, for example with a suitably shaped metal sheet, or of wood or materials deriving from wood, for example a wood- metal mix, or of other materials for example polymers or composite materials with a polymer matrix.

In some known solutions, formworks can include mobile parts, which can be activated manually or automatically, or they can be mobile in their entirety, for example moved by electro-hydraulic drives.

The metal structure can have internal articulations with removable constraints, to be disassembled and removed from a casting position after the cast has been completed and the article has reached a sufficient level of maturity.

Furthermore, the metal structure can then be positioned in a new casting position and reassembled.

So that the cast can be made through the shell, suitable reclosable apertures can be made on it, for example windows or casting unions. The apertures are kept open during casting to allow the concrete to flow, and are closed when casting is terminated, to prevent the reflux of the still fluid concrete.

Some known solutions provide that the reclosable apertures are associated, or can be associated, with a concrete distribution plant, positioned on board the form works.

It is also known that in making tunnels the concrete is cast in interstices made between the formworks and the walls of the excavations. In particular, in these cases casts are made in succession, from the bottom upward, in overlapping horizontal layers. For reasons of structural stability, alternate lateral casts are made on the two transversely opposite sides of the excavation, and finally joined with a filling at the top. The lateral casts are normally made through windows made in the shell, called hatches, while the filling at the top is made through suitable casting tubes, called casting unions, attached radially to the shell, from which the concrete is injected under pressure into the interstice.

For each casting union, naturally, an aperture is required, normally circular, on the shell of the formwork, which at the end of casting must necessarily be closed.

In order to close the aperture, it is currently known to use a suitable sliding shutter valve, of the guillotine type, having a length mating with the size of the casting union. The valve is normally provided with a hole, of a size consistent with that of the aperture in the shell, which during casting is positioned in correspondence with the casting union.

At the end of casting, the sliding shutter allows to "guillotine" the column of fresh concrete, closing the aperture.

One disadvantage of this type of valve is that an interspace or gap is generated between the shutter and the external surface of the shell; once the interspace has filled with concrete and the concrete sets, the interspace produces a protuberance which can also be dangerous, but especially is anti-esthetic on the visible surface of the article made.

The protuberance can also create problems in the disassembly of the formworks.

This disadvantage connected to this type of closing valve becomes even more serious with a higher number of apertures made in the shell, and therefore the more casting unions and the more valves there are in the formwork. The plurality of apertures, unions and valves, which are more in number than those actually used, satisfies the common need to give flexibility and variability to the casting. However, sources of possible danger or blockage due to the presence of protuberances can occur even when the casting unions are not actually used for casting.

Another disadvantage connected to using known valves for formworks is that the protuberances must necessarily be removed, in a subsequent dismantling step, which causes an increase in the times and costs of making the articles.

Some solutions are known in the state of the art concerning valve systems used for casting concrete and associated with formwork structures in the construction of tunnels.

JP 3 078987 B2 describes a valve system that uses a small pipe for casting, which is therefore not suitable for compact concretes that require the pipe to be positioned substantially perpendicular to the surface of the shuttering. This document provides a closing system that requires the pipe to slide with respect to the shuttering, which means that it is impossible to use concrete distribution systems of the automatic or semi-automatic type. Moreover, the closing system is bulkier than the thickness of the shutter, which creates problems in assembly, management, transport and other.

US 2.089.149 A describes a closing solution in which it is not possible to ensure the perfect seal of the concrete flow, since the closing is obtained by inserting cylindrical pins, not a guillotine shutter. Furthermore, the cleaning system is obtained with a cylindrical element that is separate from the sliding shutter, and this entails an increase in the volume and bulk, and also an increased difficulty in maneuvering and positioning.

JP 2003 056295 A also describes a delivery system that uses an inclined pipe, hence suitable for fluid, not compact concretes. The closing system in this case too has considerable volume and bulk. Furthermore, since it does not provide a guillotine shutter for closing, the pipe must remain connected until the device is completely closed.

JP 2001 090488 A describes an inclined pipe for delivering concrete, used for injecting concrete during mechanized excavation operations. The system cannot be used, or can only be used with great difficulty, on formworks that have a sliding shutter valve. The closing system provided in this document creates a considerable gap on the surface of the finished concrete that would make it totally unsuitable for use on a formwork.

US 2008/1 10330 also describes a casting system comprising an inclined pipe. Moreover, the position of the pipe itself prevents use of automatic or semiautomatic distribution systems. In this solution too, the delivery pipe must remain connected until the device is completely closed.

In the light of the above, purpose of the present invention is to obtain a valve for formworks that is able to close the aperture, after the concrete has been cast, made in the shell of a formwork, to prevent the reflux of the concrete, and which at the same time allows to obtain a planar visible surface, without irregularities, of the article in correspondence with and around the aperture.

The Applicant has devised, tested and embodied the present invention to overcome the problems connected to the state of the art and to obtain these and other purposes and advantages.

SUMMARY OF THE INVENTION

The present invention is set forth and characterized in the independent claims, while the dependent claims describe other characteristics of the invention or variants to the main inventive idea.

In accordance with the above purpose, a closing valve for formworks according to the present invention comprises at least a guillotine type shutter inside which an independent closing member of the sliding type is provided which, when activated, closes a through aperture present in the containing wall or shell of the formworks, without leaving a gap that can fill with fresh concrete, causing the disadvantages described above.

In one form of embodiment, the independent closing member is the axially sliding type. In one form of embodiment, the closing member is housed inside the shutter, and has an inactive position, when the shutter is in operating position where the concrete passes through the through aperture, and automatically moves to the operating position to close the gap in the shell when the shutter moves to the inactive position after completing the introduction of the concrete outside the form work.

Thanks to this configuration, the solution of the present invention does not require complex additional movements, nor does it entail additional bulk apart from that required by the shutter itself.

The reduction in bulk allows to use the valve according to the invention on very limited surfaces of the formwork.

Furthermore, since the invention separates function of closing the cast flow, obtained by moving the shutter, and the function of cleaning the final segment by closing the gap in the shell, obtained with the closing element contained in the shutter, it is possible to anticipate the disconnection of the concrete feed pipe and thus accelerate the distribution of the concrete.

According to a first solution, the closing member is mechanically connected to the shutter by threading and has a suitable abutment inside the shutter that acts as an axial end-of-travel.

According to a variant, the closing member is associated or can be associated with a corresponding actuator, for example a hydraulic or pneumatic jack, which supplies the axial movement.

Mechanical safety means can be provided to clamp the closing member in position, once it has been activated and disposed, in the operating position, associated with the through aperture in the shell of the formwork.

At the end of the casting operations, immediately after the sliding of the shutter, the closing member is moved to its abutment point, which corresponds to closing the aperture made in the shell.

According to the invention, if the formworks comprise casting unions cooperating with the through apertures to transport the concrete, at least most of the casting unions are associated with a closing valve. In this case, during the assembly of the formworks, the closing member is already positioned to close the gap and consequently no protuberances are created on the surface of the article, which retains a planar surface even in correspondence with and around the apertures.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other characteristics of the present invention will become apparent from the following description of some forms of embodiment, given as a non- restrictive example with reference to the attached drawings wherein:

- fig. 1 is a front view of a formwork having valves made according to the present invention;

- fig. 2 is an enlarged section of a valve in fig. 1, in a first operating condition; - fig. 3 is an enlarged section of a valve in fig. 1, in a second operating condition.

DETAILED DESCRIPTION OF SOME FORMS OF EMBODIMENT

With reference to the attached drawings, a closing valve according to the present invention is used to prevent the reflux of concrete in casts and is indicated in its entirety by the reference number 10.

The closing valve 10 can be used in cooperation with formworks to make concrete articles, such as the one shown schematically in fig. 1 and indicated in its entirety by the reference number 1 10.

The formwork 1 10 can be used to obtain concrete articles, whether prefabricated or cast on site.

The formwork 1 10 can also be used to obtain large-scale infrastructures such as for example bridges, underpasses, or tunnels.

However, this does not preclude the closing valve 10 and the formwork 1 10 from being applied to smaller sized concrete articles, or having different uses. With reference to fig. 1, some forms of embodiment of formworks 1 10 provide a plurality of closing valves 10, to obtain a plurality of successive concrete casts, as is normally made, for example, in the construction of tunnels.

The formwork 1 10 can include a support structure 1 11, for example metal, configured to support a containing wall or shell 1 12, shaped to reproduce the internal surface of the article to be made.

In particular, the shell has an external surface 113 which in use is located in contact with the concrete 1 18 at least until the latter has reached a level of maturation sufficient to support itself. The shell 1 12 can advantageously be made of metal sheet, or can be wood or mixed wood-metal material, or again polymer material or a composite with a polymer matrix.

The support structure 1 1 1 can include a movement unit 1 14, for example the rail type, able to move the formwork 1 10 in a desired direction, for example in the axial direction of an excavation 1 15 to be reinforced and lined internally.

The formwork 110 can be positioned by means of the movement unit 114 inside the excavation 115, so that between the shell 1 12 and the peripheral wall 1 16 of the excavation 1 15 an interstice 1 17 is created, intended to be filled with concrete 118 by casting.

The shell 1 12 can be provided with one or more through apertures 119 that put the inside of the formwork 1 10 into communication with the interstice 117 and allow the concrete 1 18 to flow toward it, during said casting.

For each through aperture 1 19 a union 120 or casting union may be provided, which defines a channel 121 with the function of conveying the concrete 118 arriving from a concrete distribution unit 122 toward the through aperture 1 19.

In preferential forms of embodiment, each channel 121 has an amplitude equal to or slightly less than the corresponding through aperture 1 19.

Fig. 1 shows, merely by way of example, a concrete distribution unit 122 located on the support structure 1 1 1 and comprising a distribution member 123 and a pipe 124 to feed the concrete 1 18 on each occasion toward a through aperture 119.

In correspondence with each through aperture 1 19, the formwork 1 10 has a closing valve 10, for example the known type with guillotine-type sliding.

The closing valve 10 is interposed between the union 120 and the corresponding through aperture 1 19 and its function is to close the latter when casting is terminated, that is, when the concrete 118 has finished flowing. This is intended to prevent any reflux of the concrete 1 18 toward the inside of the formwork 110 when it is still in its fluid state. This requirement is particularly felt when the concrete 1 18 is cast under pressure toward a zone above the formwork 1 10, as happens for example when making vaults or the upper parts of tunnels or underpasses.

Each closing valve 10 (figs. 2 and 3) includes at least a flow interruption device, or shutter 1 1, mounted sliding in a sliding compartment 12 comprised between the union 120 and the shell 1 12.

The shutter 1 1 is configured to slide in a sliding direction S substantially parallel to the shell 112.

In the case shown by way of example in figs. 2 and 3, the sliding compartment 12 is delimited by two attachment plates, connected to each other, where a first attachment plate 13 is attached for example by welding to the union 120 and a second attachment plate 14 is attached inside the shell 112.

The closing valve 10 can be provided with two limiting blocks 30, protruding laterally from the shutter 11 and having the function of limiting the travel of the latter in the sliding direction S, entering into contact with the first attachment plate 13.

In some forms of embodiment, which can be combined with other forms of embodiment described here, not shown in the attached drawings but easily implemented by a person of skill, the sliding of the shutter 1 1 can be determined by a mechanical drive, which can be manual or guided for example by a screw jack, or the hydraulic or pneumatic type, for example by means of one or more linear actuators provided with thruster cylinders.

Advantageously, a first through hole 13a can be made in the first attachment plate 13, with sizes substantially the same as those of the channel 121, while a second through hole 14a may be present in the second attachment plate 14, having more or less the same sizes as the through aperture 1 19 and positioned above it.

A through cavity 15 and a housing compartment 16, adjacent to the through cavity 15 in the sliding direction S and delimited by a peripheral wall 24, can be made in the shutter 11.

Moreover, the housing compartment 16 can be closed by a closing member 17 inserted inside it.

In some forms of embodiment, the through cavity 15 and the housing compartment 16 have the same transverse amplitude.

In other forms of embodiment, the through cavity 15 has a bigger transverse amplitude than the housing compartment 16.

In some forms of embodiment, the amplitudes of the through cavity 15 and the housing compartment 16 of the shutter 1 1 are the same as or greater than the amplitude of the through aperture 1 19 made in the shell 112.

The shutter 1 1 is configured to assume a first operating condition (fig. 2), in which the through cavity 15 is positioned in correspondence with the through aperture 1 19, substantially aligned with the through aperture 1 19, and a second operating condition (fig. 3) in which the through cavity 15 is misaligned with said through aperture 119 in order to interrupt the flow of concrete; in this position, it is the housing compartment 16, and hence the closing member 17, that is positioned substantially in correspondence with the through aperture 1 19.

In this way, when the shutter 1 1 is in its first operating condition an uninterrupted flow path is created for the concrete 118 from the channel 121 to the interstice 1 17, while in the second operating condition, the closing member 17 is in an active position and closes the through aperture 119 and interrupts said flow path. In the second operating condition, therefore, any reflux of the concrete 1 18 from the interstice 117 toward the inside of the formwork 1 10 is not possible, as will become clear hereafter.

To prevent any such reflux, the closing member 17 may include a mobile element or slider 18, mobile with respect to the containing body 1 1 along an axis of movement X, transverse to the sliding direction S.

The closing member 17 can also include guide means 19 that connect the slider 18 to the containing body 1 1, and are configured to guide the slider 18 along the axis of movement X, in order to activate it.

Advantageous forms of embodiment provide that the axis of movement X is orthogonal to the sliding direction S.

The slider 18 has sizes such that it can be completely contained in the housing compartment 16, and can have a form defined by a central body 20, for example cylindrical or polyhedral, having a first end portion 21 and a second end portion 22.

The first end portion 21 and the second end portion 22 are positioned on opposite sides with respect to the central body 20 along the axis of movement X.

In particular, the first end portion 21 is solid, that is, it has no through holes or cavities, and has sizes mating with those of the through aperture 119.

In use, the first end portion 21 is positioned nearer the shell 1 12 than the second end portion 22, which in turn is nearer the inside of the formwork 110 than the first end portion 21.

In the form of embodiment shown in the attached drawings, the first end portion 21 is an external flange 221, for example discoid, while the second end portion 22 is an internal flange 222, also discoid.

The central body 20 can have a peripheral surface 23 on which first guide means 19a can be made, configured to cooperate with second guide means 19b that can be made in the peripheral wall 24 of the housing compartment 16.

In forms of embodiment described with reference to figs. 2 and 3, the first guide means 19a and the second guide means 19b are defined by two threadings coupled to each other.

In other forms of embodiment, the guide means 19 can comprise linear actuators, for example jacks, hydraulic or mechanical, or lever mechanisms and/or cam systems, or sliders, or can include elastic spring-type thrusters.

In the specific case described here, the external flange 221 and the internal flange 222 both have a bigger diameter than that of the central body 20. Therefore, the surfaces protruding from the central body 20 define respectively an end-of- travel shoulder 25 and a closing shoulder 26.

In alternative forms of embodiment, the first end portion 21 and the second end portion 22 can have smaller sizes than the central body 20, and the end-of- travel shoulder 25 and the closing shoulder 26 can therefore be defined by recesses made in the central body 20 itself.

In some forms of embodiment, the shoulders 25 and 26 are transverse or preferably orthogonal to the movement direction X of the slider 18.

Moreover, the first end portion 21 or external flange 221 can be provided with an external surface 27 that is advantageously planar and continuous.

The peripheral wall 24 of the housing compartment 16 may have one or more protrusions that define, on opposite sides with respect to the second guide means 19b, a support surface 28 and an abutment surface 29, both facing toward the housing compartment 16 and transverse, preferably perpendicular, to the axis of movement X.

In the first operating condition of the shutter 11 (fig. 2), the slider 18 is in an inactive position, in which it can be partly or completely inside the housing compartment 16, with the external surface 27 of the external flange 221 facing the second attachment plate 14 and the end-of-travel shoulder 25 in contact with the support surface 28.

In the second operating condition of the shutter 1 1 (fig. 3), the slider 18 is in a closed position, in which it can be at least partly outside the housing compartment 16 and the external flange 221 is located inside the through aperture 1 19, plugging it. Advantageously, the slider 18 is positioned so that the external surface 27 of the external flange 221 is aligned with the external surface 1 13 of the shell 1 12.

In this way, the concrete 1 18 is prevented from passing from the interstice 1 17 toward the inside of the formwork 1 10 through the through aperture 119.

Furthermore, the motion of the slider 18 along the axis of movement X is limited by the fact that, in the closed position, the closing shoulder 26 is in contact with the abutment surface 29.

In some forms of embodiment, mechanical safety devices may also be provided, which clamp the slider 18 in the closed position.

When the guide means 19 are threaded, the motion of the slider 18 in the movement direction X can take place at the same time as it is rotated. This rotation can be conferred on the slider 18 by a movement device 31 which can be for example manual or automatic.

For example, as shown schematically in fig. 3, the movement device 3 1 can be provided with an end 32 mating in shape with a seating 33 made in the slider 18. By inserting the end 32 into the seating 33 and by rotating the movement device 31, it is possible to rotate the slider 18, which rotation allows to translate the latter in the movement direction X.

Other movement devices 31 can be provided, for example automatic and with an electric, electro-hydraulic, pneumatic or hydraulic drive, also in combination with forms of embodiment in which the threaded guide means 19 are replaced by guide means 19 of other types mentioned here.

The shutter 1 1 therefore translates in the direction of sliding S and behaves like a guillotine, cutting the flow of concrete 1 18 toward the interstice 1 17, and the slider 18, moved in the movement direction X, behaves like a closing stopper for the through aperture 119. Advantageously, the alignment of the external surface 27 of the external flange 221 with the external surface 1 13 of the shell 112 allows to obtain an article in which the concrete 1 18 is planar even in correspondence with and inside the through aperture 1 19.

It is clear that modifications and/or additions of parts may be made to the valve for formworks and to the formworks as described heretofore, without departing from the field and scope of the present invention.