Formwork, carousel-type plant and process for manufacturing prestressed reinforced concrete poles

Abstract

Formwork (1) for producing prestressed elongated reinforced concrete items, such as concrete poles intended for use in the agricultural field, comprising: - a support structure with: i) two parallel longitudinal beams (10, 10'); ii) a first reaction box (11), fixed or mobile, orthogonal to said beams; iii) a mobile second reaction box (12), slidingly constrained to the beams (10, 10'), movable between a rest position and a tension position; and - a plate (13) perimetrically fixed to the support structure and provided with a mould having a plurality of shaped channels (141) having the form of the concrete items to be cast; A carousel-type plant for producing elongated prestressed reinforced concrete items comprises one or more formworks (1) which sequentially travel through a plurality of workstations (20), where the different production steps are performed. The plant allows a rationalisation of the production factors, a reduction of energy costs, as well as an improvement of the production flexibility and product quality.

Description

[0001] TITLE: FORMWORK, CAROUSEL-TYPE PLANT AND PROCESS FOR MANUFACTURING PRESTRESSED REINFORCED CONCRETE POLES

[0002] TECHNICAL FIELD

[0003] The present invention relates to plants and processes intended for manufacturing pre-stressed reinforced concrete poles, particularly for use in the agricultural field.

[0004] BACKGROUND ART

[0005] In the agricultural field, poles are widely used not only to support plants, such as wine rows in a vineyard, but also to support systems serving agricultural works such as irrigation systems or protection systems against atmospheric threats.

[0006] In particular, cement or concrete poles intended for these types of applications are widely used for the advantages they have compared to metal (or plastic or wooden) poles.

[0007] First of all, concrete poles have excellent mechanical and chemical resistance that are not affected by climatic conditions to which they are exposed. In addition, given the same mechanical resistance, they can be made with thinner shapes thus reducing the visual impact.

[0008] Furthermore, they are not subject to corrosion and therefore do not require maintenance that would also be an issue due to the risk of polluting the soil and harming the plants.

[0009] A further advantage is intrinsically related to the use of concrete, a widely available material and much less subject to price fluctuations than ferrous metals. Last but not least, concrete poles have a lower cost than the others especially those made of metal.

[0010] It should be noted that the term “concrete poles” actually identifies products that have different compositions and structures depending on the use. For example, in applications that require a low level of mechanical resistance, the use of vibrated concrete poles is appropriate, while in heavy-duty applications, intended to withstand high stresses and loads, pre-stressed reinforced concrete poles must be used. The present invention is specially aimed at poles made of cement or pre-stressed reinforced concrete intended for heavy-duty applications e.g. tensile structures to support agrivoltaic systems or protection systems of crops against atmospheric threats or harmful insects.

[0011] From a production point of view, pre-stressed reinforced concrete poles are made by means of a process that in brief involves the following steps: firstly, a cement mixture is poured into a long mold divided into a number of channels placed side by side; then in each channel an armature is positioned and tensioned; the mold is heated to harden the mixture poured in the various channels; the tension is released in order to remove poles from the molds; finally, poles are finished and cut to size.

[0012] Currently these products are made using a manufacturing plant, schematically depicted in Figure 1 , which includes means to implement the following steps:

[0013] 1. Molds cleaning;

[0014] 2. Spreading of the mold-release fluid on the mold channels;

[0015] 3. Reinforcement strands positioning and attaching on the mold heads;

[0016] 4. Tensioning of the metal reinforcement strands;

[0017] 5. Preparation of the cement mixture in a concrete mixing plant;

[0018] 6. Pouring of the mixture on the channels and starting vibration of the mold;

[0019] 7. Chamfering of the edges of the pole;

[0020] 8. Heating of the mold to mature the mixture;

[0021] 9. Tension release of the reinforcement strands;

[0022] 10. Removal of the manufactured item from the mold;

[0023] 11. Cutting of the manufactured item to obtain a plurality of poles;

[0024] 12. Packaging of the finished poles.

[0025] In this type of system, “reactive formworks” or “self-reacting formworks” are used, i.e. formworks which integrate tensioning and relaxation heads. Due to this structure, reactive formworks have a particularly robust structure designed to withstand the heavy tension exerted by the strands and hence to prevent any deformation.

[0026] In the known art, reactive formworks are exclusively used as fixed equipment, in association with tensioning / de-tensioning machines, generally consisting of two large cylinders placed laterally to each production line.

[0027] The known process has a number of limitations and drawbacks that are reported in the following.

[0028] A first group of limitations is related to the mold, in jargon called "line", which has a very long length (between 50 m 100 m and over) and is made up of a plurality of "channels" (generally from 20 to 30) i.e. steel shapes placed side by side that impart the intended shape to the pole. The long length of the mold, due to the need of reducing production costs, makes the current process very rigid and poorly adaptable to the changing needs of the market.

[0029] Obviously, the long length of the mold makes the planning step of the production batches critic. In fact, at the same time production planning must maximize the plant yield, and hence the use of all the mold channels, as well as minimize the warehouse stock that represent a logistic issue considering the weight and volume of the products.

[0030] A further limitation of the known production process is that each production line has its own dedicated machinery and equipment needed to perform the manufacturing steps of the concrete poles. In particular, each line has its own equipment for tensioning or de-tensioning the reinforcements, a system for heating the lanes, its own machine for cutting, chamfering and smoothing the concrete poles.

[0031] Clearly the proliferation of production means determines an increase of energy costs as well as management costs due to the need to calibrate, clean and maintain a plurality of machines. Finally, a further significant issue of the current manufacturing process of pre-stressed reinforced concrete poles concerns the step where the solidified items are removed from the molds. Considerable stresses are involved in this stage that are not only energy-intensive but may damage the poles.

[0032] To complete the background art assessment, it is worth noting that “carousel” plants are known in the production of concrete items (reinforced and non-reinforced).

[0033] In these plants, a formwork moves between different stations where a number of works is carried out. In summary they include the preparation of the formwork, the pouring of the cement mixture, the unloading of the finished product. By its nature, a plant with a “carousel” configuration shares equipment and machines within the production cycle and in theory could represent a solution to the problems outlined above.

[0034] As a matter of fact, such known carousel plants are exclusively oriented to the production of concrete panels having a reinforcement made up of iron rods, which are not tensioned and are inserted in the mold before the cement mixture is poured. In this application, the formwork includes a single “tray” mold that can be partitioned thanks to magnetic separators to guarantee production flexibility i.e. panels of different sizes to be produced with the same mold.

[0035] For the purposes of assessing novelty and inventive step of the present invention, it is essential to observe that the formwork used in known carousel plants is not self-reacting. For these reasons, they are completely unsuitable for manufacturing pre-stressed reinforced concrete poles. In fact, pre-stressed reinforced concrete poles require self-reacting formworks to first tension (when the mixture is poured), and then de-tension (when the mixture has hardened) reinforcements which are made up of metal strands and not iron rods.

[0036] Attempts to modify the production process or the machinery involved in the various stations have proved unsuccessful, and there are no useful technical teachings available from the patent literature either.

[0037] In conclusion, at the moment it is not available a convincing and definitive solution to the issues described above Therefore, there is a need to improve the production processes and plants dedicated to manufacturing pre-stressed reinforced concrete poles, in particular for use in the agricultural field.

[0038] GENERAL DESCRIPTION OF THE INVENTION

[0039] Object / scope of the invention

[0040] In view of the above, the present invention intends to overcome the existing disadvantages and drawbacks of the prior art by providing an improved process for manufacturing prestressed reinforced concrete poles as well as an innovative plant that implements said process. Specifically, the main purpose of this invention is to develop a production process and an industrial plant for the production of pre-stressed reinforced concrete poles that implements said process according to the principles of so-called “lean management”.

[0041] A second important object of the present invention is to implement said process and plant in such a way as to increase flexibility in the production of pre-stressed reinforced concrete poles. In particular, the increase flexibility would allow the production of smaller batches, which can fulfill the diverse and changing needs of the market.

[0042] A third purpose of this invention is to implement said process and plant by increasing the sharing of the machines and equipment required for the production of pre-stressed reinforced concrete poles in such a way that energy costs can be reduced.

[0043] Finally, a final aim of the present invention is to develop a process and construct a plant using known technologies that allow for the production of pre-stressed reinforced concrete poles, preferably intended for the agricultural field.

[0044] Technical solution and inventive concept

[0045] These and still other purposes, which will appear more clearly in the detailed description which follows, are achieved by a novel plant for producing pre-stressed reinforced concrete poles, by the corresponding process implemented in the plant, as well as by a pole produced using said plant and process.

[0046] This carousel-type plant is based on an innovative self-reacting formwork that can be moved between multiple workstations.

[0047] Accordingly, it is an object of the present invention a self-reacting, movable formwork, whose general features are defined in the enclosed claim 1.

[0048] It is a further object of the present invention a "carousel" plant based on said formwork, having the general features of the enclosed claim 7.

[0049] It is still a further object of the present invention a production process for manufacturing concrete poles, whose general features are defined in the enclosed claim 25.

[0050] Finally, it is an object of the present invention a pre-stressed reinforced concrete pole obtained by means of the aforementioned plant and process, as defined in the enclosed claim 28.

[0051] Some advantageous embodiments of said formwork, plant and process are defined in the corresponding dependent claims. The aforesaid claims, to which reference should be made for the sake of brevity, are hereinafter specifically defined and are intended as an integral part of the present specification.

[0052] In summary, the inventive concept underlying the present invention is the optimization by sharing of the production means necessary for the production of pre-stressed reinforced concrete poles. This concept is implemented by novel mobile elements, named “self-reacting formworks” or “reactive formworks” or “reactive pallets”. Within the plant the self-reacting formworks move along a cyclical path and stop at a number of work centers (or stations) that are properly arranged to perform a sequence of processes, which will be explained in detail hereinafter.

[0053] Self-reacting formwork enables a “lean” production method, which, as will be seen below, constitutes a radical innovation compared to the known production process. In fact, as previously explained, all the processes for manufacturing the pole are performed on a single production line (or "track") which is already equipped with all the necessary machinery and equipment. Obviously, this results in significant redundancy of the production means.

[0054] Given the absolute novelty and the high technological content of the process and the related plant, the applicant has coined the term “VLS technology” (or “VLS process”), an acronym for Valente Lean System™ (registered / pending trademark of Valente Sri), to define the invention and especially to denote the superior technical characteristics of the poles obtained using this plant and process.

[0055] In addition to optimize the means of production, which leads to energy savings, the invention allows for a reduction (from 50-100 m to 10-20 m) in the length of the tracks and formwork compared to the traditional process. Accordingly, this feature allows the variety in length of the poles to be harmonized with market needs.

[0056] Brief description of drawings

[0057] The present invention will be more fully understood by reference to the following tables of drawings, in which:

[0058] Figure 1 is a functional diagram of a known process for manufacturing concrete poles intended for the agricultural field using two production lines ("tracks") that do not use machinery and equipment in shared mode;

[0059] Figure 2, with reference to the preferred embodiment of the invention, schematically shows (a) a perspective view and (b) a top view of the movable self-reacting formwork that allows the “carousel” production process to be implemented;

[0060] Figure 3 is a schematic layout of the VLS™ plant for manufacturing pre-stressed reinforced concrete poles according to the invention;

[0061] Figure 4 is a functional diagram of the VLS™ production process for manufacturing prestressed reinforced concrete poles according to the preferred embodiment of the invention, highlighting the steps performed in the carousel; Figure 5 schematically illustrates the mobile tensioning apparatus according to the preferred embodiment of the invention.

[0062] These figures illustrate and demonstrate various features and embodiments of the present invention but are not to be construed as limiting the invention.

[0063] DETAILED DESCRIPTION OF THE INVENTION

[0064] For the sake of fully disclose the invention, a detailed description of a preferred, but not exclusive, embodiment of the various units of the plant and steps of the production process according to the invention is provided hereinafter.

[0065] The self-reacting movable formwork (1).

[0066] It is an object of the present invention a self-reacting movable formwork for use in the production of pre-stressed reinforced concrete poles.

[0067] Said formwork, which is the basis of the “carousel” plant / process according to the invention, is indicated with the reference number (1) in the enclosed Figure 2.

[0068] The self-reacting formwork (1) is essentially made up of a support structure formed by two longitudinal beams (10,10’) parallel to each other and by two transverse beams (12,12), also named “reaction boxes” (or “head boxes”), orthogonally attached to the first ends (101 , 10T) and to the second ends (102,102’) so as to form a rectangular structure which typically has a length of 12 m and a width of 3 m.

[0069] As in the known self-reacting pallets, the reaction boxes (12,12) cooperate with the formwork to put in a tensioned state the reinforcements of the poles according to a procedure that will be described below.

[0070] In the preferred embodiment, the first reaction box (12) is attached to the longitudinal beams (10,10’) so as to form a “U” structure, while the second box (11) is mobile.

[0071] In particular, the second reaction box (11) is slidingly constrained to the longitudinal beams (10,10’) through fixing means that allow the second reaction box (11) to be displaced from a rest position in which the pole reinforcements are relaxed, to a tensioning position in which said reinforcements are tensioned. More details will be provide in hereinafter.

[0072] Furthermore, the second reaction box (11) includes holes in which locking pins (or similar devices) are inserted to block the mobile box (11) on the longitudinal beams (10,10’) and hence to prepare the reinforcements in the expected tensioning state.

[0073] However, in an alternative embodiment (not shown) both reaction boxes (12,12) are slidably constrained to the longitudinal beams (10, 10’) so that each can be moved from the rest position to the tensioning position where they are temporarily blocked by inserting locking pins into the holes obtained in both boxes (12,12).

[0074] In the preferred embodiment, the fixing means that slideably constrain the mobile reaction box (11) to the longitudinal beams (10,10’), allowing translation from the rest position to the tensioning position, and vice versa, consist of a couple of pin-slot couplings consisting of two pins (111 ,121’) protruding from the ends of the mobile reaction box (11), each being constrained to a corresponding longitudinal “C” slot (103,103’) obtained on the internal surface of the longitudinal beams (10,10’).

[0075] In alternative embodiments, means for slidingly constraining the mobile box (11) to the longitudinal beams (10,10’), are pin-slot couplings, guide-shoe, wheel / rail, rack-pinion, bearings or other equivalent means well known to those skilled in the art.

[0076] The self-reacting formwork (1) according to the invention is characterized in that a plate (13) is attached to the support structure along its perimeter at the bottom. The plate (13) is provided with a mold (14) which is divided into a plurality of channels (141), shaped with the form of the poles that are intended to be made.

[0077] In the preferred embodiment, the channels are all the same, although in alternative embodiments they can be different in length or section according to needs.

[0078] The mold can be made from a high-thickness metal sheet suitably shaped and welded to the plate. The mold can also be made in a single piece. Preferably, the channels (141) are all the same and in a number between 8 and 25 per mold (beyond this number the formwork becomes too large and less rigid making its use challenging).

[0079] In addition, the self-reacting formwork (1) according to the invention is also characterized by pockets (122,122) obtained, respectively, on the reaction boxes (12,12). As will be explained in detail hereinafter, the guide masks are inserted and retained in these pockets (122,122). Guide masks are metal plates fixed to the ends of the pole reinforcement and have the function to maintain the strands in the correct position.

[0080] During the production cycle, the self-reacting formwork (1) is heavily stressed and could bend once the reinforcements are tensioned. For these reasons, it is essential that the formwork (1) has high rigidity. For this purpose, the longitudinal beams (10,10’) have a considerable thickness, for example 300 mm, while the plate (13) has a thickness preferably of 10 mm. Furthermore, the plurality of channels (141) contribute to the rigidity of the formwork (1).

[0081] The self-reacting formwork (1) according to the invention is equipped with gripping means which, as will be explained hereinafter, allow a filter machine to grip and tilt the formwork (1) so that the solidified poles can be extracted from the channels (141).

[0082] With reference to the enclosed Figure 2, in the preferred embodiment the gripping means are holes (104,104') obtained on the longitudinal beams (10,10') which constitute gripping points for the tongs of the filter machine.

[0083] In this embodiment, the filter is configured so that it first grips the longitudinal beams (10,10’) laterally, and then rotates the formwork (1) by 180° around the axis parallel to the beams.

[0084] In alternative embodiments, the gripping means may be different, for example, they are pins protruding from the longitudinal beams (10,10’). Furthermore, the gripping points for the filter tongs may be obtained on the reaction boxes (12,12).

[0085] The self-reacting formwork (1) according to the invention is characterized in that it is mechanically associated with a motion system that allows the formwork (1) to travel along a path within the production site.

[0086] In the preferred embodiment, the motion system comprises a plurality of motorized wheels (15) fixed to the floor of the factory so as to form a path. To facilitate sliding along the path, the formwork (1) is guided by floor rails.

[0087] Optionally, the motion system includes not only driving wheels but also a plurality of idle wheels. Alternatively, the motorized wheels (15) fixed to the floor can be replaced by a plurality of motorized roller conveyors arranged to form a path.

[0088] In alternative embodiments, the motorized wheels (15) can also be attached directly to the structure of the formwork (1).

[0089] In further embodiments, the movement system includes a motorized carriage that tows a formwork (1) having a structure equipped with a plurality of idle wheels (15).

[0090] It shall be evident to those skilled in the art how combinations of the motion systems described above are possible.

[0091] Carousel plant to produce pre-stressed reinforced concrete poles (2).

[0092] A further object of this invention is a carousel plant (2) for manufacturing pre-stressed reinforced concrete poles based on the self-reacting formwork (1) previously described.

[0093] In summary, with reference to the enclosed Figures 3 and 4, the plant (2) comprises a plurality of work stations (20) where all the operations needed to manufacture the poles are performed. In the preferred embodiment, described herein by way of illustration and not limitation of the present invention, the carousel plant (2) includes the following nine stations (20): a cleaning and mold-oiling station (21); a reinforcement-preparing station (22); a tensioning station (23); a casting and compaction station (24); a smoothing and rounding station (25); a curing station (26); an extraction station (27); a cutting station (28); a packaging station (29).

[0094] Said plurality of stations (20) are connected by a pathway (P) which defines the entire processing cycle.

[0095] In this preferred embodiment, the self-reacting formwork (1) travels along a pathway (P’) which connects a subset of the stations (20).

[0096] In other words, the self-reacting formwork (1), is cyclically displaced along the pathway (P’), from the cleaning and mold-oiling station (21) to the extraction station (27) in such a way that all the intermediate works intended for the stations (22,23,24,25,26) are performed in a sequence. The production cycle continues outside the carousel with the cutting (28) and packaging (29) stations where poles emerge ready for delivery to the warehouse or to the customer.

[0097] In the preferred embodiment, the stations (21 ,22,23,24,25,26,27) are connected to each other by means of a plurality of motorized wheels (15) attached to the floor of the factory and arranged to form the pathway (P’).

[0098] In this embodiment, the path (P’) is substantially circular and is centered on the maturation station (26) with the extraction station (27) placed near the cleaning and mold-oiling station (21). With this arrangement, the self-reacting formwork (1) that has completed the path (P’) is prepared to begin a new processing cycle.

[0099] Even if a circular arrangement is preferable, the path (P’) can have other arrangments, for example, zig-zag, or star-shaped, depending on the needs.

[0100] With reference to the preferred embodiment, a description of the diverse stations and processes performed therein is provide in the following.

[0101] Cleaning and mold-oiling station (21)

[0102] With reference to the enclosed Figure 2, the self-reacting formwork (1) starts the processing cycle from the extraction station (27) where the poles have been removed from the mold (14). In the station (21) the formwork (1) is cleaned and a release oil is spread on the mold (14) by means of, respectively, a cleaning system (210) and a spraying system (211).

[0103] The cleaning device (210) has been specifically designed for cleaning a formwork (1) divided into channels (141) intended for the production of poles or elongated products alike.

[0104] Actually, in addition to the cement residues typical of any pre-stressed reinforced concrete product, in the manufacturing of poles a longitudinal encrustation, approximately 1 cm wide, is formed on the upper part of each of the two walls of the channels (141) during the rounding and smoothing operations (as will be explained later).

[0105] The cement encrustations must be removed because it makes difficult to remove the poles from the mold (14) in the formwork extraction station (27). Furthermore, if not removed regularly, they grow and harden over time to the point that a grinder is needed to remove the encrustations an operation which should be avoided as the walls of the channels (141) may get damaged.

[0106] Consequently, in the preferred embodiment the cleaning system (210) includes: a first cleaning device (2101) equipped with two lateral brushes for cleaning the two longitudinal beams (10,10’); a second cleaning device (2102) comprising pairs of blades (as many as the channels) appropriately spaced to allow the removal of the cement incrustations; a third cleaning device (2103) equipped with brushes or brooms (as many as the channels) for cleaning the bottom of the channels (141).

[0107] The lateral brushes, the pairs of blades and the brushes or brooms are mounted on a carriage that can be displaced vertically, i.e. perpendicularly to the formwork (1), and along the entire length of the channel (141). It shall be evident to those skilled in the art how an automation of this type can be easily obtained by means of known technology.

[0108] In this way, the cleaning operation of the formwork (1) is carried out entirely in a single pass by first lowering and then moving the diverse cleaning elements along the channels (141).

[0109] The spraying system (211) includes a plurality of spraying devices (2111), as many as the number of channels (141) of the mold (14).

[0110] In the preferred embodiment, the spraying devices (2111) are hydraulic nozzles or atomizers inserted at an appropriate mutual distance in a head body which is fluidically connected, via a manifold and ducts, to a source of compressed air and to a tank containing a pressurized release fluid.

[0111] In turn, the head is fixed to the mobile carriage on which the cleaning devices are mounted.

[0112] With this arrangement, the formwork is cleaned and oiled in a single pass using the same machine. However, in alternative embodiments, these two operations can be carried out at different times on the same machine or even implemented on different machines that are placed in the same station or in different stations depending on the needs.

[0113] In any case, the spraying system (211) is designed to deposit a thin layer of release fluid, generally an oil, over the entire surface of the channels (141) in the most possible uniform way, so that dry and excessively oily spots which can deteriorate the surface of the poles are avoided. These requirements cannot be fulfilled using known spraying systems, which are designed for the production of large pre-stressed concrete slabs and provide for a “cascade” spraying operation, i.e. from top to bottom, wherein the spray nozzles are positioned vertically or perpendicular to the formwork.

[0114] Advantageously, the present inventors have placed the nozzles of the spraying system (211) in a position inclined with respect to the vertical so that a thin stream of release fluid is ejected. The stream has an axis inclined with respect to the vertical, so as to optimally direct the flow of release fluid particles onto the walls. Alternatively, the same effect can be achieved by placing the sprayers in a vertical position and using nozzles configured to eject a stream at a precise angle.

[0115] Reinforcement-preparing station (22)

[0116] The self-reacting formwork (1) cleaned and oiled in the previous station (21) is ready for receiving the reinforcement which, in the case of pre-stressed reinforced concrete poles (or other similar elongated structures), consists of a certain number of metal strands (221), typically 4 or 6 depending on the section of the pole.

[0117] The preparation of the strands (221) is an important step because it determines the mechanical resistance of the pole. For this purpose, to correctly position and lay the strands inside the channels (141), guide masks are used. As mentioned before, the masks are metal plates (222) having a geometry corresponding to the section of the pole and through holes (223) obtained on their surfaces.

[0118] In detail, in this station (22) the strands (221) are first cut to size and inserted into the holes (223,223') of two guide masks (222,222'); then the first ends of the strands (221) are blocked with cable lugs (224), or equivalent components, on the first mask (222) while the second mask (222') is made to slide until it reaches the free ends of the strands (221); finally, the strands (221) are blocked on the second guide mask (222') by means of cable lugs (224'), or equivalent components such as bushings or locking pins.

[0119] Once prepared, the reinforcement is positioned in the self-reacting formwork (1) by first inserting the two guide masks (222,222’) into special pockets (122,122) obtained on the opposing reaction boxes (12,12) and then by keeping the mobile reaction box (11) in the rest position.

[0120] From the description provided, it shall be apparent that the system according to the invention introduces a remarkable innovation in the field since the reinforcement are prepared, inserted in the channels (141) and tensioned in separated steps.

[0121] Therefore, it is advantageously possible to cut the strands (221) to size and to block their ends on the guide masks (222,222’) “off-line” since they require a considerable amount of time and manual work. It is even possible to set up a warehouse of ready-to-use reinforcements according to the different types of poles to be produced.

[0122] Tensioning station (23)

[0123] The self-reacting formwork (1) arrives at this station after the reinforcements prepared in the previous station have been inserted into the channels (141) of the mold (14).

[0124] In this station (23) the reinforcement consisting of a series of metal strands (221) is tensioned by at least one mobile tensioning apparatus (231). Said apparatus (231), which is illustrated in the enclosed Figure 5, constitutes a radically new component of the carousel system (2) according to the invention.

[0125] In fact, differently from the known art, the mobile tensioning apparatus (231) is not a piece of equipment exclusively dedicated to a specific production line (or "track") but, consistently with the inventive concept underlying the present invention, it is a shared machine available to the self-reacting formwork (1) which at a given moment arrives at the tensioning station (23).

[0126] More specifically, the mobile tensioning apparatus (231) is a translating machine that performs the following operations: it enters the path (P’) of the carousel; tensions the reinforcements (221) present in the channels (141) of the self-reacting formwork (1); then exits the carousel and finally enters a waiting mode until a new formwork arrives.

[0127] In the preferred embodiment, described herein by way of illustration and not limitation of the present invention, the self-reacting formwork (1) includes a single mobile reaction box (11) and consequently the tensioning station (27) includes a single mobile tensioning apparatus (231) which is obviously positioned on the side of the mobile reaction box (11).

[0128] In this embodiment, the mobile tensioning apparatus (231) includes a tensioning means (2311) attached to a body (2312) mounted on wheels (2313) so that the tensioning means (2311) is able to translate between a working position (235) and two lateral rest positions (234,234') along a track (2314) parallel to the mobile reaction box (11). Furthermore, the tensioning means (2311) includes: coupling means (2315) attached to said body (2312) to temporarily secure the mobile reaction box (11) to the mobile tensioning apparatus (231); two doubleacting hydraulic cylinders (2311) attached to the body (2312) and positioned so that the stems can be brought into contact with the ends of the longitudinal beams (10,10').

[0129] In this way, when the formwork (1) reaches the tensioning station (23), the mobile tensioning apparatus (231) performs the following operations: first it is displaced along the track (2314) from a first rest position (234) to the working position (235); then the coupling means (2315) secure the mobile reaction box (11) to the body (2312) of the mobile tensioning apparatus (231); finally, the stems of the hydraulic cylinders (2311) push the first ends (101 ,101') of the longitudinal beams (10,10') putting the strands (221) under tension.

[0130] Once the correct tensioning state is achieved, according to the mechanical characteristics of the poles to be constructed, the mobile reaction box (11) is locked and held in position by means of special locking pins inserted into the holes provided. This operation is preferably carried out manually by a specialized operator, although it can be automated in a way that is obvious to those skilled in the art.

[0131] The pins are then inserted into holes made in the longitudinal beams (10,10') and placed in positions corresponding to the holes in the mobile reaction box (11). In this way, the insertion of the locking pins securely fix the mobile box (11) to the longitudinal beams (10,10'). Advantageously, each hole is positioned to correspond to the optimal level of tension for a specific type of pole.

[0132] Once the locking pins are inserted, the mobile tensioning apparatus (231) performs the following further operations: the stems of the hydraulic cylinders (2311) are retracted; the body (2312) of the mobile tensioning apparatus (231) is released from the mobile box (11); the mobile tensioning apparatus (231) is displaced from the working position (235) to the second rest position (234') symmetrically opposite to the first, where it awaits the arrival of the next formwork (1).

[0133] It shall be evident that equivalent methods for tensioning the strands (221) are possible.

[0134] In alternative embodiments, the hydraulic cylinders (2311), instead of pushing the ends of the longitudinal beams (10,10'), pull the mobile reaction box (11) and move it from the rest position to the tensioning position. In this case, the tensioning station (23) can include locking / unlocking means to lock and unlock the formwork (1) and prevent it from moving.

[0135] In further embodiments, the self-reacting formwork (1) includes two identical mobile reaction boxes (12,12) and therefore the tensioning station is equipped with two identical mobile tensioning apparatuses (231 ,231').

[0136] By acting in a manner similar to that described, the two mobile tensioning apparatuses (231 ,231') are displaced, respectively, from one of the rest positions (234,234') and (236,236'), to the working positions (235) and (237); then, they are secured to the respective mobile reaction boxes (12,12) and alternatively, or simultaneously, exert a pushing force on the first ends (101 ,101') and on the second ends (102,102') of the longitudinal beams (10,10') in order to tension the strands (221). The desired tensioning state is blocked by introducing the locking pins into the holes obtained in the longitudinal beams (10,10') which in this case are placed both in correspondence with the first ends (101 ,101') and the second ends (102,102').

[0137] At the end of the operation the two mobile tensioning apparatuses (231 ,231') are displaced towards one of the rest positions (234,234') and (236,236'), respectively.

[0138] Casting and vibro-compaction station (24)

[0139] When the self-reacting formwork (1), travelling along the path (P’), reaches this station, a cement mixture, preferably a cement-based concrete is cast into the channels (141) of the mold (14) where the reinforcement has been properly positioned and tensioned therein.

[0140] According to known techniques, the concrete is prepared and stored in a concrete mixing equipment and conveyed via a distribution system to a dosing machine (241), for example of the type comprising a dosing unit fed by a travelling bucket or by a concrete loader slidingly constrained to the frame of the machine (241) so as to allow the dosing unit to translate over the surface of the mold. Preferably, the channels (141) are completely filled with the cement mixture so that the surface is level with the top edge of the mold.

[0141] In this same station, hydraulic vibrators or electric vibrators (242), of a known type, are applied to the self-reacting formwork (1) according to the invention in order to compact the concrete and remove air bubbles.

[0142] In the preferred embodiment, electric vibrators (242) placed above the formwork (1) are employed. In alternative embodiments, the vibrators (242) are instead placed under the formwork or laterally. Compared to plants for manufacturing concrete poles of the known type, characterized by channels even 100 m long and more, the present invention advantageously allows to significantly limit the travel of the dosing unit to about 12 m only, i.e. to the length of the formwork (1) and thus to save time and energy consumption.

[0143] Smoothing and rounding station (25);

[0144] Once the mold (14) has been filled and the cement mixture, preferably a cement-based concrete, has been compacted, it is necessary to smooth and round the surfaces of the pole (1) while the mixture is still fresh.

[0145] Therefore, the self-reacting formwork (1), travelling along the path (P’), reaches this station (25) where it finds a shaping machine (251) equipped with a template (252) that performs the following operations: the cement surface is first leveled and smoothed, as in known solutions; then the edges of the soft poles within the channels (141) are rounded; finally, a transverse line with a “V” section is imprinted on each pole forming (and for this reason registered as a design by Valente Sri) and an additional company trademark is optionally imprinted.

[0146] In the preferred embodiment, the formwork (1) moves to the smoothing and rounding station (25) while the shaping machine (251) is stationary. In this embodiment, the shaping machine (251) comprises a frame having a template (252) attached thereto. The profile (252) is lowered by means of a suitable actuator almost to contact with the cement mixture (the surface of the cement mixture is level with the top edge of the channel).

[0147] In an alternative embodiment, the formwork (1) stops at the smoothing and rounding station (25) while the shaping machine (251) is mobile. Said machine (251) comprises a carriage that can be moved vertically, i.e. perpendicular to the formwork (1), and along the entire length of the mold (14).

[0148] A template (252) is attached to the carriage, which is first lowered almost to contact with the cement mixture (the surface of the mixture is level with the top edge of the channel) and then translated along the entire length of the mold (14).

[0149] In this embodiment, the finishing operations are carried out with a single pass of the translating carriage over the mold (14) using a single template (252) shaped accordingly.

[0150] Alternatively, these operations are carried out with successive passes and separate equipment, for example, leveling, smoothing, rounding of sharp edges and imprinting of the transverse line in a single pass with a translating template (252), while the branding is imprinted by means of a mold (253).

[0151] In further embodiments, the levelling and smoothing of the fresh concrete surfaces is carried out by means of a vibrating bar or oscillating bar straight edge, as in known types of systems, while the rounding of sharp edges, the imprinting of the transverse line and the branding are performed by means of one or two templates or molds (252,253).

[0152] In any case, the template (252) is made of steel or wear-resistant plastic material. Preferably, it is made of silicone material or a technopolymer whose surfaces can be appropriately treated to reduce the adhesion of the cement mixture. Advantageously, these materials do not damage the formwork (1) and are much less affected by wear than steel.

[0153] In any case, while leveling and smoothing the surfaces is required for aesthetic reasons, rounding the edges of the forming pole is required for functional reasons. In fact, sharp edges and corners can cut the hail protection nets (supported by concrete poles) and also damage the beaters used in the grape harvesting machines.

[0154] Any residues of cement mix detached from the moving template (252) are removed later.

[0155] Once these operations are completed, the self-reacting formwork (1) travelling along the path (P’) reaches the next maturation station (26).

[0156] Curing station (26).

[0157] In this station (26) the self-reacting formwork (1) enters a climatic chamber (261) where it remains for a certain time, in a closed environment, so that the concrete casted in the channels (141) mature and solidified poles are obtained.

[0158] According to known techniques, a control unit sets, monitors, and if necessary adapts the maturation parameters set inside the chamber, so that all the poles reach the same degree of maturation regardless of their position in the mold (14) and in the climatic chamber (261). Clearly, the maturation times depend on the specific cement mixture used and the geometric characteristics of the pole.

[0159] In the preferred embodiment, the station (26) with the climatic chamber (261) is conveniently placed in a central position of the plant (2) near the first station (21) and the last station (27) connected by the path (P’).

[0160] In this embodiment, the climatic chamber (261) is sized to accommodate three self-reacting formworks (1) which are stacked on top of each other by means of a known type of elevator system.

[0161] In other embodiments, the station (26) includes two or more climatic chambers (261). According to needs, each climatic chamber (261) is dedicated to cure formworks (1) intended for manufacturing of poles having specific lengths and cross-sections. Advantageously, this solution provides further flexibility to the system (2) according to the invention.

[0162] Extraction station (27).

[0163] The self-reacting formwork (1) exiting the climatic chamber (261) transports a number of cured, i.e. perfectly solidified, poles still inside the channels (141) of the mold (14). The formwork (1) concludes the path (P’) by entering the extraction station (27) where the cured poles are extracted from the mold (14).

[0164] In the plant (2) according to the invention, this operation is carried out by means of a filter (271), of a known type, which in summary consists of the following unit: a hollow structural section (2711) made of metal which forms a box-like structure designed to receive the self-reacting formwork (1); a lift (2712) slidably connected to the structure (2711) which comprise attachment means (2714), e.g. grippers, arranged in such a way that the holes (104,104') obtained on the longitudinal beams (10,10') are used as gripping points; an electromechanical system equipped with a control for the rotation of the formwork (1) around the longitudinal axis parallel to the beams (10,10'); a movable plate (2715) on which the poles extracted from the channels (141) are placed.

[0165] With this configuration, the elevator (2712) descends along the tubular structure (2711) and is stopped at a position where the coupling means (2714) are coupled with the holes (121 ,121). When the elevator (2712) reaches in this position, the formwork (1) is lifted and, once it has reached a suitable height, it is rotated 180° around the longitudinal axis.

[0166] Contrary to the known technique in which the concrete products (typically slabs) must be held on the formwork by fixing blades to prevent them from falling, in the extraction station (27) of the plant (2) according to the invention, the poles do not fall by gravity since the strands (221) are still tensioned and hold the poles within the channels (141) of the upturned mold (14).

[0167] Consequently, the extraction station (27) according to the invention includes a mobile detensioning apparatus (272), having an identical structure and working according a symmetrical operation mode of the mobile tensioning apparatus (231) which is present in the tensioning station (23).

[0168] In the preferred embodiment of the present invention, the mobile detensioning apparatus (272) is a translating machine distinct from the mobile tensioning apparatus (231).

[0169] In alternative embodiments, the path (P’) is designed so that the mobile tensioning apparatus (231) in the tensioning station (23) operates as a mobile detensioning apparatus (272) in the extraction station (27).

[0170] In any case, the tensioning device (2721) is configured so that, once the locking pins are removed, the mobile reaction box (11) is released and is moved from the tensioning position, corresponding to the arrival condition at station (27) of the formwork (1), to the rest position in which the poles fall by gravity from the channels (141) and are placed on the plate (2715).

[0171] Advantageously, the extraction station (27) and the related process require much less energy and also subjects the poles to a lower stress. In this way, a reduction in breakages and damage to the poles is achieved and a remarkable limitation of the traditional machinery and process is overcome.

[0172] The mobile plate (2715) travels along the path (P’) towards the next cutting station (28) while the self-reacting formwork (1) is returned to the initial cleaning and oiling station (21) of the plant (2) according to the invention.

[0173] Cutting station (28).

[0174] The poles placed on the plate (2715) reach the cutting station (28) still having excess strands

[0175] (221) and the guide masks (222) retained by the cable lugs (224). First, the masks (222) and the cable lugs (224) are removed by cutting the ends of the poles.

[0176] Then they are recuperated by operators who take them back to the reinforcement station (23), after having cleaned them appropriately.

[0177] Subsequently, the poles, or other elongated products, are aligned and automatically cut to size.

[0178] In the cutting station (28) according to the invention, both cutting operations are performed with a conventional automatic machine (281) which, unlike the prior art solutions, is advantageously shared between all the formworks (1). It is evident that concentrating the cutting operations in a single station (in known solutions each “track” is equipped with a dedicated cutting machine) leads to numerous advantages.

[0179] First of all, costs due to the redundancy of resources and the need to keep them properly maintained are avoided. In particular, a reduction in energy cost is achieved.

[0180] Second, energy consumption is also reduced due to the fact that the cutting machine (281) must travel a shorter distance (at most 20 m compared to 120 m as in known types of systems). Finally, a greater control over the cutting operation and thus a reduction of cutting waste are achieved.

[0181] Packaging station (29).

[0182] The carousel system (2) according to the invention finally includes a packaging station (29) equipped with a palletizing machine (291) which, using technologies and methods known in the field, organizes the cut-to-size poles into a bundle and packages them using straps and plastic film, or other material.

[0183] However, compared to station od the known type, in the packaging step, the bundle of poles is palletized by incorporating strips in the lower part of the bundle that allow the insertion and removal of the forks of the forklifts used in the loading and unloading operations. It shall be apparent to those skilled in the art that the plant and related production process described above, which has been named “Valente Lean System™", constitute a radically innovative state-of-the-art innovation in the production of elongated pre-stressed concrete products, particularly poles intended for the agricultural field.

[0184] Process for the production of pre-stressed reinforced concrete poles.

[0185] It is an object of the present invention a process for the production of pre-stressed reinforced concrete poles, implemented by the previously described carousel plant (2). With reference to Figure 4, this process includes the following steps: a) obtain a self-reacting formwork (1) according to the invention; b) subject said formwork (1) to cleaning using a cleaning system (211) comprising: a first cleaning device (2101) equipped with two lateral brushes for cleaning the two longitudinal beams (10,10'); a second cleaning device (2102) comprising pairs of blades, as many as the channels (141), suitably spaced to allow the removal of the cement residues; a third cleaning device (2103) equipped with brushes or brooms, as many as there are channels (141), for cleaning the bottom of the channels (141); c) subject said formwork (1) to oiling by applying a mold-release fluid to the surfaces of the channels (141) of the mold (14) using a spraying system (211) comprising a plurality of spraying devices (2111), as many as the number of channels (141), wherein said spraying devices (2111) project a jet of mold-release fluid having the axis inclined with respect to the vertical; d) for each of said channels (141), cut one or more metal strands (221) to size, insert them into the holes (223,223') of two guide masks (222,222') blocking the ends exiting from said holes (223,223') with cable lugs (224), or equivalent means, to obtain a prepared reinforcement; e) position each of said prepared armatures in the channels (141) by inserting the two guide masks (222,222') into suitable pockets (122,122) obtained on the opposing reaction boxes (11 ,12), and by keeping the mobile reaction box (11) in rest position; f) translate a mobile tensioning apparatus (231) from a first rest position (234) to a working position (235) in the pathway (P’), wherein at least one tensioning means (2311) of said tensioning apparatus (231) tension the reinforcements (221) inserted in the channels (141) by moving the mobile reaction box (11) from a rest position to a tensioning position; g) apply blocking means to stably constrain the mobile box (11) to the longitudinal beams (10,10') of said formwork (1) in a position corresponding to a predetermined state of tension of the reinforcement (221) based on the mechanical features of the poles to be built; h) translate the mobile tensioning apparatus (231) from the working position (235) to a second rest position (234') equal to or different from said first rest position (234); i) cast a cement mixture using a dosing machine (241) into each of the channels (141) of the formwork (1) having the reinforcement prepared in step d) positioned therein; j) subject said formwork (1) to compaction using hydraulic or electric vibrators (242) to eliminate air bubbles and to compact the cement mixture casted into the channels (141) of the mold (14); k) perform one or more of the following finishing operations: level or smooth the cement surface in each channel (141); round the edges of the poles being formed in each of the channels (141); impress a transversal line on each pole in formation; imprint the company brand; l) introduce the self-reacting formwork (1) inside a climatic chamber (261) and, once closed; set, monitor and if needed adapt the temperature, the degree of humidity, the air flow inside the climatic chamber (261) and the maturation time so that all the poles reach the same degree of maturation regardless of their position in the mold (14) and in the climatic chamber (261); at the end of curing, extract the self-reacting formwork (1); m) rotate the self-reacting formwork (1) by 180° using a filter (271) and keep the reinforcement (221) in a state of tension, to obtain a rotated formwork; n) remove the blocking means applied in step g) from the formwork (1); o) translate a mobile detensioning apparatus (271) from a first rest position (274) to a working position (275) in the pathway (P’), and move the mobile reaction box (11) of said rotated formwork from a tensioning position to a rest position, wherein in said working position (275) the tension of the reinforcements (221) inserted into the channels (141) is released by means of a tensioning means (2711) of said detensioning apparatus (271); p) let the poles fall by gravity from the channels (141) of the mold (14) onto a plate (2715); q) translate the mobile detensioning apparatus (271) from the working position (275) to a second rest position (274') equal to or different from said first rest position (274); r) subject the self-reacting formwork (1) to the previous step from b) to q); s) perform one or more cutting operations to remove the reinforcements (221) protruding from the poles, separate the masks (222) and the cable lugs (224), and to cut the poles to size; t) optionally, package one or more poles cut to size to form a package, incorporating strips in the lower part of the package to facilitate loading and unloading operations.

[0186] It shall be evident to those skilled in the art that in the case where the system (2) according to the invention includes two mobile tensioning apparatuses (231 ,231') the steps f), g), h), n), o) and q) listed above must be accordingly modified in a trivial manner on the basis of the disclosure provided.

[0187] CONCLUSIONS

[0188] It has been found that the invention described hereinabove fully achieves the intended aim and objects.

[0189] Although the description and examples provided contain many details, they should not be interpreted as limiting the invention, but simply as illustrative illustrations of some embodiments of the present invention. Indeed, numerous variations are possible. For example, the way the system stations are placed along the path or the order of the process steps, as well as the way of the different stations and the corresponding processing steps are aggregated may be different from the disclosure provided.

[0190] Therefore, any modifications of the present invention that fall within the scope of the following claims are considered to be part of the present invention.

[0191] Where the characteristics and techniques mentioned in any claim are followed by reference signs, these reference marks have been applied solely for the purpose of increasing the intelligibility of the claims and consequently these reference marks have no limiting effect on the interpretation of each element identified by way of example from these reference signs.

Claims

CLAIMSWhat is claimed:1) Self-reacting formwork (1) for use in a plant intended to produce pre-stressed elongated reinforced concrete items, said formwork (1) comprising a support structure consisting of two longitudinal beams (10.10') parallel to each other; a first reaction box (11), fixed or mobile, which is orthogonally fixed to said beams (10,10') or slidingly-constrained thereto in a orthogonal manner, wherein said box (11), if mobile, is provided with first means allowing its translation from a rest position, in which the reinforcements of said elongated structures are relaxed, to a tension position in which said reinforcements are tensioned, and vice versa a second mobile reaction box (12) slidingly-constrained in a orthogonal manner to said beams (10,10'), wherein said box (12) is provided with second means allowing its translation from a rest position, in which the reinforcements of said elongated articles are relaxed, to a tension position in which said reinforcements are tensioned, and vice versa, said self-reacting formwork (1) being characterized in that it comprises a plate (13) perimetrically fixed to the support structure and provided with a mould which is subdivided into a plurality of shaped channels (141) having the form of said elongated items, said self-reacting formwork (1) being further characterized in that it is mechanically associated with a handling system configured to move said formwork (1) along a pathway (P’) within a production site.2) Self-reacting formwork (1) according to claim 1 wherein the handling system comprises:a plurality of motorized wheels or roller tracks (15) fixed to the floor of the plant to form a pathway (P’); or floor rails arranged along said pathway (P’) to slide the formwork (1); or a plurality of idle wheels arranged along said pathway (P’) to slide the formwork (1).3) Self-reacting formwork (1) according to claim 1 or 2 wherein the handling system comprises: a plurality of motorized wheels (15) fixed directly to the structure of said formwork (1); one or more motorized roller tracks arranged along said track (P’); a motorized wagon pulling a formwork (1) having a structure equipped with a plurality of idle wheels (15).4) Self-reacting formwork (1) according to one or more of the preceding claims wherein the reaction boxes (12,12) have pockets (122,122) in which metal plates, i.e. guide masks (222) to proper position the reinforcements, can be inserted and temporarily retained.5) Self-reacting formwork (1) according to one or more of the preceding claims wherein: the first reaction box (11) is fixed orthogonally to the first ends (101 ,101') of said beams (10,10'); the second mobile reaction box (12) is slidingly-constrained in a orthogonal manner to the second ends (102,102') of said beams (10,10') by couplings means of the type: pin / spline, pin / slot, guide / sliding shoe, wheel / rail, rack / pinion or bearings.6) Self-reacting formwork (1) according to claim 5 wherein said means for slidingly constraining the mobile reaction box (11) are a double pin-slot coupling consisting of two pins (111 ,121') protruding from the ends of said mobile box (11), each beingconstrained to a corresponding longitudinal slot (103,103') obtained on the longitudinal beams (10,10').7) Plant (1) of the carousel type for producing elongated pre-stressed reinforced concrete items, said plant comprising: a plurality of workstations (20) connected by a pathway (P); and one or more self-reacting formworks (1) according to one or more of claims 1 to 6, said plant being characterized in that said formwork (1) reaches a subset of said plurality of stations (20), travelling along a section (P’) of the pathway (P), wherein said subset includes at least the following stations (20): a cleaning and mold-oiling station (21) of said self-reacting formwork (1); optionally, a reinforcement-preparing station (22); a tensioning station (23) of said self-reacting formwork (1); a casting and compaction station (24) of a cement mixture; a smoothing and rounding station (25) of said elongated items in formation; a curing station (26) of said manufactured items; an extraction station (27) of solidified manufactured items, wherein said stations are separated or are at least partially integrated with each other.8) Plant (1) according to claim 7 further comprising the following stations: a cutting station (28) of said solidified manufactured articles; a packaging station (29) of said solidified manufactured articles.9) Plant (1) according to claim 7 wherein said cleaning and mold-oiling station (21) includes means configured to perform formwork (1) cleaning and mold oiling (14) operations by means of, respectively, a cleaning system (210) and a spraying system (211), wherein said cleaning system (210) includes: a first cleaning device (2101) for cleaning the two longitudinal beams (10,10');a second cleaning device (2102) for removing the cementitious residues on the walls of the channels (141) at the end of the operations performed in the smoothing and rounding workstation (25); a third cleaning device (2103) for cleaning the bottom of the channels (141), and wherein said spraying system (211) includes: one or more spraying devices (2111) for applying a mold-release fluid to the walls (141) of the channels (14) to facilitate removing of said elongated items from the channels (14) in the extraction station (27).10) Plant (1) according to claim 9 wherein: the first cleaning device (2101) is provided with two side brushes for cleaning the two longitudinal beams (10,10'); the second cleaning device (2102) comprises pairs of blades, as many as the number of channels (141), suitably spaced to allow the removal of cementitious residues; the third cleaning device (2103) comprises brushes or brooms, as many as the number of channels (141), for cleaning the bottom of the channels (141); the spraying devices (2111) are nozzles or atomizers, as many as the number of channels (141), to eject a jet of mold-release fluid having axis inclined with respect to the vertical, wherein said side brushes, pairs of blades, brushes or brooms and said spraying devices are mounted on a carriage which can be moved vertically, i.e. perpendicularly to the mold (1), and along the entire length of the mold (14).11) Plant (1) according to claim 7 wherein the tensioning station (23) includes a mobile tensioning apparatus (231) configured to translate a tensioning means (2311) between at least one lateral rest position (234) and a working position (235) in which said means(2311) tension the reinforcements (221) inserted in said channels (141) by moving the first mobile reaction box (11) from a rest position to a tensioning position, wherein said rest and tensioning positions correspond, respectively, to the condition of arrival of the formwork (1) at the tensioning station (23) and of departure therefrom.12) Plant (1) according to claim 11 wherein the mobile tensioning apparatus (231) includes a tensioning means (2311) fastened to the body (2312) of said apparatus (231), said tensioning means (2311) comprising: coupling means (2315) for temporarily securing the mobile box (11) to the mobile tensioning apparatus (231); two double-acting hydraulic cylinders (2311) fixed to the body (2312) and positioned so that the stems can be brought into contact with the ends of the longitudinal beams (10,10'); coupling means fixed to said body (2312) for temporarily secure / release the mobile reaction box (11) to the mobile tensioning apparatus (231); two hydraulic cylinders (2312) fixed to said body (2312) and having stems configured to push the first ends (101 ,101') of the longitudinal beams (10,10'); locking means for stably constraining the mobile box (11) to the longitudinal beams (10,10') in a position corresponding to a predetermined state of tension of said reinforcement (221), said body (2312) which is mounted on wheels that can be moved along a track to allow translation of the mobile box (11) between said lateral rest position (234) and said working position (235).13) Plant (1) according to claim 7 and 11 wherein the tensioning station (23) includes an additional mobile tensioning apparatus (23T) configured to translate a tensioning means (2311) between at least one lateral rest position (236) and a working position(237) wherein said means (2311) tension the reinforcements (221) inserted in said channels (141) by moving the first mobile reaction box (11) from a rest position to a tensioning position, wherein said additional mobile tensioning apparatus (23T) includes: tensioning means (2311) fixed to the body (2312) of said tensioning apparatus (231); coupling means fixed to said body (2312) to secure / release the second mobile box (12); two hydraulic cylinders (2312) fixed to said tensioning means (2311) and having stems configured to push the second ends (102,102') of the longitudinal beams (10,10'); locking means to stably fasten the second mobile box (12) to the longitudinal beams (10,10') in a position corresponding to a predetermined state of tension of said reinforcement (221), said body (2312) which is mounted on wheels that can be moved along a track to allow translation parallel to the mobile box (11) between said lateral rest position (236) and said working position (237).14) Plant (1) according to claim 7 wherein said casting and compaction station (24) includes: a dosing machine (241) configured to receive a cement mixture from a concrete mixing equipment and to cast said mixture into the channels (141) of the mold (14) where the reinforcements have been positioned and tensioned; one or more hydraulic or electric vibrators (241) applied above or below the selfreacting formwork (1), or on the sides thereof, said vibrators (241) which are configured to remove air bubbles and to compact the cement mixture.15) Plant (1) according to claim 7 wherein said smoothing and rounding station (25) includes a fixed shaping machine (251) which operates on a movable formwork (1), said shaping machine (251) comprising a frame to which a template (252) is constrained, said template which, via a suitable actuator, can be lowered towards the cement mixture, so that during the translation of the formwork (1) the exposed surface of the elongated items being formed in the channels (141) is levelled and smoothed, the sharp edges of said items are rounded and a transversal line on said surface is obtained.16) Plant (1) according to claim 7 wherein said smoothing and rounding station (25) includes a mobile shaping machine (251) which operates on a fixed formwork (1), said shaping machine (251) comprising a vertically mobile carriage, i.e. perpendicular to the formwork (1), and along the entire length of the mold (14), wherein said shaping machine (251) includes: a template (252), fastened to said carriage, configured so that during the translation along the mold (14), the exposed surface of the elongated items being formed in the channels (141) is levelled and smoothed, the sharp edges of said items are rounded and a transversal line on said surface is obtained; or optionally, a mold (253) configured to imprint the company brand on the exposed surface of the elongated items being formed in the channels (141).17) Plant (1) according to claim 15 or 16 wherein said template (252) is made of a material selected from the group consisting of: steel, technopolymer, silicone, carbon, equivalent wear-resistant materials, or a combination thereof.18) Plant (1) according to claim 7 wherein said maturation station (26) includes: one or more climatic chambers (261) configured to accommodate one or more selfreacting formworks (1) placed side by side or stacked together; anda control unit (262) configured to set, monitor and, if needed, to adapt the maturation parameters, so that all the items reach the same degree of maturation regardless of their location in the mold (14) and in the chamber climate (261).19) Plant (1) according to claim 7 wherein said extraction station (27) includes: a filter (271) configured to secure the self-reacting formwork (1) and to allow 180° rotation thereof around the longitudinal axis parallel to the beams (10,10'); a mobile detensioning apparatus (272) configured to translate a tensioning means (2711) between at least one lateral rest position (274) and a working position (275), in which said means (2711) moves said mobile reaction box (11) from a tensioning position to a rest position, wherein said positions correspond, respectively, to the condition of arrival of the formwork (1) at the extraction station (27) and departure therefrom; optionally, a plate (2715) configured to collect the elongated items that fall by gravity from the channels (141).20) Plant (1) according to claim 19 wherein said filter (271) includes: a box-like structure (2711) in metal tubing inside which the self-reacting formwork (1) arrives; an elevator (2712) slidably attached to said structure (2711) and comprising coupling means (2714) configured to couple with the gripping points (121 ,122) obtained on the transverse axis of the reaction boxes (11 ,12); an electromechanical system configured to rotate the formwork (1) by 180° around the longitudinal axis parallel to the beams (10,10'), once it has been blocked by said coupling means (2714); a plate (2715) on which the elongated items extracted from the channels (141) are placed.21) Plant (1) according to one or more of claims 7 to 20 wherein the pathway (P’) covered by said formwork (1) has a shape selected from the group consisting of: circular, zigzag, star, or a combination thereof.22) Plant (1) according to one or more of claims 7 to 21 characterized in that the pathway (P’) is configured so that the mobile detensioning apparatus (272) of the extraction station (27) is the mobile tensioning apparatus (231) of the tensioning station (23), said mobile tensioning apparatus / detensioning apparatus (231 ,272) being configured to translate between at least one rest position (234,274) to two working positions (235,275) respectively associated with the stations (23,25).23) Plant (1) according to one or more of claims 7 to 22 characterized in that said formwork (1) has a length of less than 25 m, preferably less than 15 m.24) Plant (1) according to one or more of claims 7 to 22 characterized in that said elongated items are poles intended for the agricultural field.25) Process for the production of pre-stressed reinforced concrete poles including the following steps: a) obtain a self-reacting formwork (1) according to one or more of claims 1 to 6; b) subject said formwork (1) to cleaning using a cleaning system (211) comprising: a first cleaning device (2101) equipped with two lateral brushes for cleaning the two longitudinal beams (10,10'); a second cleaning device (2102) comprising pairs of blades, as many as the channels (141), suitably spaced to allow the removal of the cement residues; a third cleaning device (2103) equipped with brushes or brooms, as many as there are channels (141), for cleaning the bottom of the channels (141); c) subject said formwork (1) to oiling by applying a mold-release fluid to the surfaces of the channels (141) of the mold (14) using a spraying system (211) comprising aplurality of spraying devices (2111), as many as the number of channels (141), wherein said spraying devices (2111) project a jet of mold-release fluid having the axis inclined with respect to the vertical; d) for each of said channels (141), cut one or more metal strands (221) to size, insert them into the holes (223,223') of two guide masks (222,222') blocking the ends exiting from said holes (223,223') with cable lugs (224), or equivalent means, to obtain a prepared reinforcement; e) position each of said prepared armatures in the channels (141) by inserting the two guide masks (222,222') into suitable pockets (122,122) obtained on the opposing reaction boxes (11 ,12), and by keeping the mobile reaction box (11) in rest position; f) translate a mobile tensioning apparatus (231) from a first rest position (234) to a working position (235) in the pathway (P), wherein at least one tensioning means (2311) of said tensioning apparatus (231) tension the reinforcements (221) inserted in the channels (141) by moving the mobile reaction box (11) from a rest position to a tensioning position; g) apply blocking means to stably constrain the mobile box (11) to the longitudinal beams (10,10') of said formwork (1) in a position corresponding to a predetermined state of tension of the reinforcement (221) based on the mechanical features of the poles to be built; h) translate the mobile tensioning apparatus (231) from the working position (235) to a second rest position (234') equal to or different from said first rest position (234); i) cast a cement mixture using a dosing machine (241) into each of the channels (141) of the formwork (1) having the reinforcement prepared in step d) positioned therein; j) subject said formwork (1) to compaction using hydraulic or electric vibrators (242) to eliminate air bubbles and to compact the cement mixture casted into the channels(141) of the mold (14); k) perform one or more of the following finishing operations: level or smooth the cement surface in each channel (141); round the edges of the poles being formed in each of the channels (141); impress a transversal line on each pole in formation; imprint the company brand; l) introduce the self-reacting formwork (1) inside a climatic chamber (261) and, once closed; set, monitor and if needed adapt the temperature, the degree of humidity, the air flow inside the climatic chamber (261) and the maturation time so that all the poles reach the same degree of maturation regardless of their position in the mold (14) and in the climatic chamber (261); at the end of curing, extract the self-reacting formwork (1); m) rotate the self-reacting formwork (1) by 180° using a filter (271) and keep the reinforcement (221) in a state of tension, to obtain a rotated formwork; n) remove the blocking means applied in step g) from the formwork (1); o) translate a mobile detensioning apparatus (271) from a first rest position (274) to a working position (275) in the pathway (P), and move the mobile reaction box (11) of said formwork rotated from a tensioning position to a rest position, wherein in said working position (275) the tension of the reinforcements (221) inserted into the channels (141) is released by means of a tensioning means (2711) of said detensioning apparatus (271); p) let the poles fall by gravity from the channels (141) of the mold (14) onto a plate (2715); q) translate the mobile detensioning apparatus (271) from the working position (275) to a second rest position (274') equal to or different from said first rest position (274); r) subject the self-reacting formwork (1) to the previous step from b) to q);s) perform one or more cutting operations to remove the reinforcements (221) protruding from the poles, separate the masks (222) and the cable lugs (224), and to cut the poles to size; t) optionally, package one or more poles cut to size to form a package, incorporating strips in the lower part of the package to facilitate loading and unloading operations.26) Process according to claim 25 wherein the cleaning step b) and / or the oiling step c) are performed by a single pass of cleaning devices and spraying devices integral with a vertically mobile carriage, i.e. perpendicular to the formwork (1), and along the entire length of the channel (141).27) Process according to claim 25 or 26 wherein the finishing step k) is performed in a single pass by translating templates and / or by imprinting molds integral with a carriage which can be moved vertically, or perpendicularly to said formwork (1), and along the entire length of the channel (141).28) Pre-stressed reinforced concrete pole including: a matrix made from the solidification / maturation of a cement mixture; a system of reinforcements incorporated into said matrix, characterized in that it is obtained by the process according to one or more of claims 26, 27 or 28.29) Concrete pole according to claim 29 for use in the agricultural field for the support of tree crops, for the support of crops in rows, in the construction of greenhouses and in the construction of agrivoltaic systems.

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