The present invention relates to the manufacturing of cementitious articles, in particular of cementitious mortar based composite panels with light translucency properties. In particular, the present invention relates to a new method for making a cementitious mortar based composite panel. The present invention also relates to a composite panel comprising such a structure and to a monolithic structure made of translucent material which can be used in the aforesaid method.
The use of cementitious articles with light translucency properties is known. As known, a possible manufacturing process of such cementitious articles (e.g. described in patent application WO03097954) includes the use of optical fibers inside the articles which are then finished off into blocks or panels. However, such a technology has proven to be rather ineffective because the translucency effect, i.e. the transmission of light from one side of the panel to the other, is conditioned by the light intensity incident on the block and of its incidence angle. It has been seen that beyond a given value of such an angle, the translucency effect gradually decreases, this constituting an obvious limitation of such a technique. Other drawbacks related to this technology are found, for example, in the difficult positioning of the optical fibers in the block and the need for complicated steps of cutting and polishing to finish off the article. This obviously implies waste of material, particularly if large parts are required.
It is know that the limitations and problems related to the foregoing solution are overcome in part by using cementitious mortar based composite panels comprising portions of light translucent material, which are of the “through” type, i.e. extend through the entire thickness of the panel. With this regard, patent application EP 2376718 describes some embodiments of such composite materials in which the light translucent elements are made of polymethyl methacrylate (PMMA). In order to obtain such panels, the PMMA elements are positioned inside a formwork and arranged according to parallel lines by exploiting appropriate spacers which keep the elements reciprocally spaced apart from one another. The formwork is then filled with cementitious material to bury the PMMA elements without the opposite faces thereof coming into contact with the mortar. The cementitious mortar is thus hardened and the panel is extracted from the formwork.
With respect to the use of optical fibers, the PMMA elements are more effective because the translucency effect is reached in all cases, also in presence of unfavorable light angles. Furthermore, from the manufacturing point of view, the manufacturing of PMMA elements substantially does not cause any processing waste, i.e. waste of material. However, it has been observed that the methods for making panels with PMMA elements currently have huge drawbacks which require a solution in order to make this technology easily useable.
With this regard, again with reference to the solution described in EP 2376718, the PMMA elements appear as longitudinal elements characterized by portions having a height equal to the thickness (through portions) of the panel and connected to lower height portions according to a substantially “chain-like” development. It has been seen that there are two critical aspects in the cost formation of each “chain-like” element, the first of which is the cost of the material, and more specifically of the PMMA rectangle from which the “chain” is obtained. The second aspect relates to the cost of the cutting process used to configure such elements. Furthermore, the PMMA elements are made “to size”, i.e. as a function of the required size of the panels. This is a further criticality in terms of manufacturing costs.
A further drawback of “optical” nature has arisen in the use of the panels made with “chain-like” elements caused by the joint regions between the “through portions” and the lower height portion of the elements themselves. Indeed, such regions appear “dark”, or in all cases opaque, to an observer observing the panel according to a direction of observation different from that perpendicular to the panel itself. It is seen that this optical phenomenon is, in many cases, a deterrent to purchasing and in general to using the panels in general.
It has equally been found that the current production of panels is based on a substantially hand-crafted procedure, requiring a manual positioning of the single PMMA element (chains) in the formwork. Such a positioning requires care and diligence by the operators. At the same time, the pouring operations of the cementitious mortar in the formworks require particular care to limit possible misalignment of the PMMA elements as much as possible. Indeed, it has been found that in the manufacturing process described above, panels are often obtained in which the chains are arranged “irregularly” because parallelism is poor and straightness lacks. This firstly compromises the good appearance results of the panels themselves and thus the final quality of the product.
Thus, the need for manufacturing methods alternative to the current ones clearly arises to reduce manufacturing time and end costs, in particular, according to the conditions indicated above. At the same time, the need arises to have higher quality panels, the inner structure of which does not determine drawbacks of optical nature as that described above.
It is the main task of the present invention to provide a new method for making a cementitious mortar based composite panel with light translucency properties which allows to overcome the drawbacks of the prior art. In the scope of this task, it is a first object to provide a method which allows to simplify in considerable manner the steps of assembly which precede the pouring of the cementitious mortar. It is a further object of the present invention to make the manufacturing of panels more cost-effective avoiding processing and material waste as much as possible. A further object of the present invention is to provide high quality panels the inner structure of which does not originate drawbacks of optical nature. A not last object of the present invention is to provide a method which is reliable and easy to implement at competitive costs.
This task and these objects are reached by means of a manufacturing method as indicated in claim 1. Such a method is thus based on the use of a monolithic structure made of light translucent plastic material, which is preferably obtained by means of a plastic injection molding process. Such a structure comprises a base and elements which are developed therefrom according to a predetermined arrangement. The positioning of the monolithic structure within a formwork is advantageously obtained by means of a single operation at the end of which the plastic material elements assume the predetermined position for the pouring. With respect to the traditional methods, this translates into a considerable reduction of manufacturing costs.
According to a further aspect, the monolithic structure is modular to the advantage of higher versatility in terms of the possibility of obtaining panels of different sizes. Indeed, multiple monolithic structures may be used during the step of assembly which precedes the pouring the modular according to the desired size of the panel, the combination of which monolithic structures facilitates the positioning of all the translucent material elements needed to make the panel in the formwork. This solution allows to further reduce manufacturing costs. Furthermore, the positioning of such modular structures does not require qualified, specialized personnel and is also suitable for possible process automation.
Further features and advantages will be apparent from the following detailed description of the manufacturing method of the cementitious article according to the present invention illustrated by way of non-limitative example by means of the accompanying drawings:
The same reference numbers and letters in the figures refer to the same elements or components.
The present invention thus relates to a method for making a cementitious mortar based composite panel comprising a plurality of elements 55, 55′, 55″ made of light translucent material which allows the light transmission through the panel 1 from one first flat side 1′ to a second flat side 1″ of the panel itself.
The method according to the present invention includes making a monolithic structure 3 of light translucent material adapted to be incorporated, following the pouring of cementitious mortar and subsequent hardening thereof, in a cementitious article. The latter will be then finished/squared off so as to define the panel 1, and in particular its flat sides 1,1′ indicated above. For the purposes of the present invention, the expression “monolithic structure” means a structure made in one piece by means of a plastic injection molding process of light translucent material, such as, for example the PMMA typically used for this type of applications.
As specified in greater detail below, the structure 3 in addition to being “monolithic” is preferably modular to allow the combination with other monolithic structures 3′,33,33′,66,66′,99,99′, which are functionality and constructively equivalent, as will be described in greater detail with regards to FIGS. from 9 to 11. Such a modular combination allows to make panels of different size without needing to change the size of the monolithic structure of translucent material for this purpose. In other words, varying the size of the panel implies varying the number of monolithic structures used, but not varying the size of the structures themselves, which may be advantageously made in series.
The plan view in
Again with reference to
According to a preferred arrangement, shown in the figures, the elements 12 of each row are arranged in longitudinally offset position with respect to the elements 12′,12″ of the adjacent rows. In particular, each element of a first row of elements (indicated by reference numeral 12) faces a corresponding separation space defined between two elements of a second row of elements (indicated by reference numeral 12′) on a first side and a corresponding separation space defined between two elements of a third row of elements (indicated by reference numeral 12″) on a second side. Consequently, the elements 12′ of the second row and the elements 12″ of the third row are symmetric with respect to the first row of elements 12′.
It is understood that the foregoing offset arrangement is to be understood as preferred and is thus not binding. Consequently, the elements 12, 12′, 12″ of the structure 3 could have a different arrangement. Similarly, the cross-section of the elements 12,12′,12″ could also be different from the rectangular shape indicated above as preferred embodiment.
As mentioned above, in order to increase the versatility of the method for making the panels, the monolithic structure 3 is modular by virtue of the presence of reference means for the modular coupling of the structure itself with a second equivalent structure. With reference to FIGS. from 2, 3, 4 and 6, the base 10 of the structure 3 preferably defines a perimeter comprising a first crosswise peripheral portion 21 and a second crosswise peripheral portion 22, which also extend according to the crosswise direction 202. Such crosswise portions 21, 22 each define a “reference toothing” comprising recesses 31,31′ alternating with protrusions 33,33′. More specifically, the first crosswise peripheral portion 21 defines a first reference toothing, while the second crosswise peripheral portion 22 defines a second reference toothing. For example,
With reference to the exploded view in
In the embodiment shown in
With reference to
If the elements 12, 12′,12″ are arranged in “offset” rows as shown in the figures, the grid 60 may advantageously have rhomboid shaped meshes 61 each of which indeed surrounds at least one element 12,12′,12″ of the structure 3. In a possible embodiment (not shown), the width of the meshes 61 of the grid could be such to surround an assembly of elements 12, 12′, 12″ of the structure 3.
According to a preferred embodiment, the grid 60 is arranged at a predetermined height from the base 10 of the structure 3 preferably by using suspension means which keep the grid 60 suspended with respect to the base 10′ of the structure 3 while pouring the cementitious mortar. In this manner, the grid 60 will be incorporated in an intermediate portion 1′,1″ of the panel which will be obtained at the end of the method of manufacturing. FIGS. from 12 to 15 show a possible embodiment of such suspension means which appear in the form of suspension rings 99 (preferably but not exclusively made of deformable plastic material, e.g. rubber) which surround one or more elements 12, 12′, 12″ of the structure 3 at a predetermined height. With this regard, if the rings 99 surround one single element (
The suspension means described above as other possible functionally equivalent, may be positioned so that the grid 60 remains raised with respect to the base 10 by a predetermined value, e.g. ⅓ or ⅔ of the height 84 of the elements 12′,12′,12″. It is however in the scope of the present invention the possibility of arranging the grid 60 at a different height, in all cases sufficient to guarantee that the grid 60 and the suspension means remain distanced from the base 10 in order to prevent them from remaining visible at the end of the manufacturing of the panel.
Preferably, the suspension means of the grid are arranged only in some predetermined positions of the structure 3 sufficient to keep the grid 60 raised. In the examples shown in FIGS. from 12 to 15, suspension rings 99 are each arranged in position close to one of the four angles of the structure 3. The number and position of the rings 99 may be advantageously varied according to the extension of the structure 3.
Furthermore, it is included in the present invention the possibility of arranging a plurality of metallic grids 60,60′ in the formwork 200 above all when manufacturing thick panels. This solution allows to increase the strength of the panel itself. With this regard,
This means that if the elements of the structure 3 have an arrangement different from the offset arrangement shown in the figures, then the shape of the grid or grids used may be different from the rhomboid shape shown in the figures. If the elements of the structure 3 are aligned in all directions (i.e. are aligned longitudinally and crosswise) a square or rectangular mesh grid may be used, for example.
In order to facilitate the positioning and the centering of the monolithic structure 3 in the formwork 200, in a preferred embodiment, the method includes arranging reference profiles shaped in manner geometrically corresponding to the peripheral portions 21,22,23,24 of the base 10 of the structure 3 on the bottom of the formwork 200. In the example in
Indeed, the use of reference profiles 51,52,53,54 allows an easy positioning of the structure 3 and its correct positioning during the subsequent pouring. In other words, the reference profiles 51,52,53,54 allow to arrange and keep the monolithic structure 3 in a predetermined position inside the formwork 200 also facilitating in this manner the subsequent steps of finishing off of the cementitious mortar 2 obtained after the pouring and hardening of the cementitious mortar. In all cases, it is understood that the monolithic structure 3 could be arranged in the formwork 200 regardless of the presence of such reference profiles 51,52,53,54.
With this regard,
Following the step of hardening of the cementitious mortar, a cementitious mortar is thus obtained in which the elements 12,12′,12″ of the monolithic structure 3 and the grid 60, if present, arranged between the elements themselves are incorporated. The base 10 of the monolithic structure 3 is substantially arranged on a side of the cementitious article corresponding substantially to the formwork 200. At this point, the method according to the invention includes finishing off the cementitious article by eliminating the base 10 of the structure 3 so that only portions of the elements 12,12′,12″ of the structure itself are incorporated. Such portions correspond to the portions 55,55′,55″ of the panel 1 according to the objects of the method of the present invention.
From the above it is apparent that with respect to traditional methods, the method according to the invention allows a considerable reduction of manufacturing time because the elements 12,12′,12″ made of light translucent materials are all arranged in the formwork 200 in a single operation, which corresponds to the positioning of the monolithic structure 3.
FIGS. from 9 to 11 show further peculiarities of the method according to the invention related to the modularity features which characterize the monolithic structure 3.
As shown in
In the examples shown in FIGS. from 9 to 11, it is apparent that the advantage of using modular structures 3,33,33′,66,66′,99,99′ for creating cementitious mortar based composite panels. According to the desired size of the panel, it will be sufficient to arrange a formwork 200 of corresponding size and one or more monolithic structures (having equivalent shape and size) which will be combined/positioned inside the formwork 200 in extremely rapid manner by exploiting the various reference means (crosswise and longitudinal reference means) defined on the peripheral portions 21,22,23,24 of the structures and possible the reference profiles preventively arranged inside the formwork 200. The fact of using a plurality of monolithic structures 3,33,33′,66,66′,99,99′ which can be obtained by means of the same plastic injection process is a considerable advantage in terms of functional versatility. Substantially, the need to vary the size of the panel for production reasons does not impact on the manufacturing process of the monolithic structures. This implies a considerable reduction of manufacturing costs. As described above, the modularity principle may be advantageously applied also to possibly making and using reference profiles for positioning the monolithic structures inside the formwork.
It is further worth noting that the modularity expressed above is particularly advantageous because it allows to obtain panels with different optical translucency effects. Indeed, monolithic structures 3,33,33′,66,66′,99,99 could be made with translucent materials having different color. The subsequent modular combination of such structures could thus allow to make panels having translucent zones with different colors.
The method according to the invention allows to fully fulfill the predetermined tasks and objects. In particular, the method allows to considerably reduce manufacturing making the desired panels usable at costs extremely lower than the methods currently used for the same purpose. Furthermore, the method according to the invention is very versatile because it allows to easily differentiate panel manufacturing in terms of size.
Number | Date | Country | Kind |
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MI2014A000324 | Mar 2014 | IT | national |
Filing Document | Filing Date | Country | Kind |
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PCT/EP2015/054474 | 3/4/2015 | WO | 00 |