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Title:
IMPROVED FRICTION SEISMIC ISOLATOR OF THE MOBILE PENDULUM TYPE
Document Type and Number:
WIPO Patent Application WO/2021/181254
Kind Code:
A1
Abstract:
An improved friction seismic isolator (1) of the mobile pendulum type comprising a lower plate (2) which is arranged close to a foundation structure; an upper plate (3) which is arranged above the lower plate (2) along a longitudinal axis (Y) and contributes to supporting an elevation structure to dissipate the kinetic energy transmitted to the elevation structure by a natural phenomenon or by a human- caused event and provided with a high release of total energy, a mobile dissipation pendulum (4) arranged in simple support against the lower plate (2) and the upper plate (3) between which it is interposed in such a way as to swing freely on an inner surface (2a, 3a) of the lower plate (2) and the upper plate (3) according to one or more random side directions, orthogonal to the longitudinal axis (Y), alternately between an equilibrium position, taken in absence of the natural phenomenon or the human-caused event, in which the mobile dissipation pendulum (4), the lower plate (2) and the upper plate (3) are substantially coaxial to each other, and a plurality of instability positions, taken while the natural phenomenon or the human-caused event is in progress, in which the mobile dissipation pendulum (4), the lower plate (2) and the upper plate (3) are offset from each other, to dissipate the kinetic energy of the natural phenomenon or the human-caused event, transmitted to the elevation structure. In particular, the mobile pendulum (4) has, at least one of the two side faces (4a, 4b) axially opposite each other along the aforesaid longitudinal axis (Y), a plurality of surface recesses (5) facing towards the outside, inside which sliding inserts (6) made of high-friction coefficient plastic material are housed.

Inventors:
COLATO GIANPAOLO (IT)
Application Number:
PCT/IB2021/051931
Publication Date:
September 16, 2021
Filing Date:
March 09, 2021
Export Citation:
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Assignee:
FIP MEC S R L (IT)
International Classes:
E04H9/02; E01D19/04
Attorney, Agent or Firm:
CONTADIN, Giorgio et al. (IT)
Download PDF:
Claims:
CLAIMS

1 . Improved friction seismic isolator (1 ) of the mobile pendulum type comprising: a lower plate (2) suitable to be arranged close to a foundation structure; an upper plate (3) arranged above said lower plate (2) along a longitudinal axis (Y) and suitable at least to contribute to support an elevation structure in order to dissipate the kinetic energy transmitted to said elevation structure by a natural phenomenon or by a human-caused event and provided with a high release of total energy; at least one mobile dissipation pendulum (4) arranged in simple support against said lower plate (2) and said upper plate (3) between which it’s interposed in such a way as to swing freely on an inner surface (2a, 3a) of said lower plate (2) and said upper plate (3) according to one or more random side directions, orthogonal to said longitudinal axis (Y), alternately between an equilibrium position, taken in absence of said natural phenomenon or said human-caused event, in which said mobile dissipation pendulum (4), said lower plate (2) and said upper plate (3) are substantially coaxial each other, and a plurality of instability positions, taken while said natural phenomenon or said human-caused event is in progress, in which said mobile dissipation pendulum (4), said lower plate (2) and said upper plate (3) are offset each other, to dissipate said kinetic energy of said natural phenomenon or said human-caused event, transmitted to said elevation structure, characterized in that said mobile pendulum (4) presents, in correspondence of at least one of the two side faces (4a, 4b) axially opposite each other along said longitudinal axis (Y), a plurality of surface recesses (5) facing towards the outside, inside two or more of which sliding inserts (6) made of high friction coefficient plastic material are housed.

2. Isolator (1 ) according to claim 1 ), characterized in that said surface recesses (5) are uniformly distributed on at least one of said side faces (4a, 4b) of said mobile pendulum (4).

3. Isolator (1 ) according to claim 1 ) or 2), characterized in that each of said surface recesses (5) presents a circular profile with which the profile of each of said sliding inserts (6) matches. 4. Isolator (1) according to any of the previous claims, characterized in that said sliding inserts (6) protrude from at least one of said side faces (4a, 4b) of said mobile pendulum (4).

5. Isolator (1 ) according to any of the previous claims, characterized in that each of said sliding inserts (6) presents a thickness in the range 2÷10 mm.

6. Isolator (1 ) according to claim 5), characterized in that said thickness of each of said sliding inserts (6) presents a value in the range 4÷8 mm.

7. Isolator (1) according to claim 5) or 6), characterized in that said thickness of each of said sliding inserts (6) is equal to 7 mm.

8. Isolator (1 ) according to any of the previous claims, characterized in that each of said sliding inserts (6) presents an outer surface (6a), facing said inner surface (2a, 3a) of said lower plate (2) and/or said upper plate (3), with a convexity-shaped profile that combines with the concavity of the profile of said inner surface (2a, 3a) of said lower plate (2) and/or said upper plate (3).

9. Isolator (1) according to any of the previous claims, characterized in that said plastic material of said sliding inserts (6) is a thermoplastic resin or a thermosetting resin.

10. Isolator (1) according to claim 9), characterized in that said thermoplastic resin is any of the plastic materials selected from the group consisting of polytetrafluoroethylene (PTFE), ultra-high-molecular-weight polyethylene (UHMWPE), polyoxymethylene (POM), polyamides (PA) and/or their combinations in variable proportions, while said thermosetting resin is any of the plastic materials selected from the group consisting of phenolic resin, amide resin, epoxy resin, polyurethane resin, unsaturated polyester resin, silicone resin, alkyl resin and/or their combinations in variable proportions.

11. Isolator (1 ) according to any of the previous claims, characterized in that the friction coefficient of said plastic material of said sliding inserts (6) is different for at least two of said sliding inserts (6).

12. Isolator (1) according to any of the previous claims, characterized in that said plastic material with which said sliding inserts (6) are made is different for at least two of said sliding inserts (6). 13. Isolator (1 ) according to any of the previous claims, characterized in that the central body (7) of said mobile pendulum (4) is made of metallic material.

14. Isolator (1) according to any of the previous claims, characterized in that said inner surface (2a, 3a) of said lower plate (2) and/or of said upper plate (3) is covered with a mirror-polished laminar cap (8) made of metallic material and having roughness, normally expressed in Rz, less than 1 .

15. Isolator (1) according to claim 14), characterized in that said laminar cap (8) is simply inserted into an annular seat made in the inner perimetrical edge (2b, 3b) of said lower plate (2) and/or said upper plate (3).

Description:
IMPROVED FRICTION SEISMIC ISOLATOR OF THE MOBILE PENDULUM TYPE

The present invention relates to the field of civil constructions and, more in detail, relates to an improved friction seismic isolator of the sliding pendulum type (single or double), used for the protection of buildings.

It is known that in the field of civil engineering and architecture, the expression "seismic isolators" indicates support devices, used to isolate either structurally or physically the load-bearing structure of the buildings from the disruptive and often devastating effects of an abrupt and sudden natural event, such as an earthquake. A particular type of dissipative seismic isolators (or supports) of known type, to which the present invention specifically refers, is called "mobile pendulum" in the basic variant, and "double mobile pendulum" in the more articulated variant; these seismic isolators are also known in the industry by the acronym FPS, which stands for "Friction Pendulum System".

Such seismic isolators are intended to be applied between the foundations (or foundation structure) of a civil structure (e.g. such as a building or bridge) and the civil structure (or elevated structure or superstructure) itself, to protect it from a seismic shock or impact human-caused event. One of the seismic isolators performing this function is the dissipative support device described in patent US4,644,714 A; as customary practice for components of this type, it comprises a lower support (or anchor plate) and an upper support (or striker plate), integral respectively to the foundation structure (substructure) and the elevated structure (superstructure). Both said supports comprise a respective concave sliding surface, one facing the other, along a linear, generally vertical axis in the rest or equilibrium condition of the device, and are separated from each other by a sliding and dissipation shoe (or lens or pad) generally made of metallic material (e.g. such as carbon-filled steel) which, when necessary, swings freely in the gap created between the two plates (hence the term "pendulum" to identify the isolator at issue).

In turn, the sliding and dissipation shoe includes two convex outer surfaces opposite each other, in contact and mating with the concave sliding surfaces of the upper and lower support plates of the seismic isolator, to form a spherical articulation.

In the case of a simple mobile pendulum, the seismic isolator incorporates a single sliding and dissipation shoe, in contact with both the lower anchor plate and the upper striker plate, while in the case of a double mobile pendulum, the seismic isolator incorporates two sliding shoes coupled to each other, one in contact with the lower anchor plate and the other in contact with the upper striker plate.

In the presence of an earthquake, the sliding and dissipation shoe is thus free to slide with pendulum motion relative to the lower support (or anchor plate), protecting the superimposed structure from the potentially devastating, and in any case highly dangerous and risky effects of the earthquake.

The sliding and dissipation shoe arranged simply resting on the lower and upper plates between which it is interposed, thus swings freely on the concave surface of the lower support plate and the upper support plate according to one or more random (but generally radial) side directions, orthogonal to the linear axis, alternately between a position of rest or equilibrium, assumed in the absence of the aforesaid natural phenomenon or human-caused event, in which the sliding and dissipation shoe, the anchor plate and the striker plate are substantially coaxial to each other, and a plurality of consecutive positions of structural instability, assumed while the natural phenomenon or human-caused event is occurring, in which the sliding and dissipation shoe, the lower support plate and the upper striker plate are variably offset from each other, to dissipate the kinetic energy of the natural phenomenon or human-caused event, transmitted to the elevated structure.

At the convex external surface (the one in contact with the concave surface of both the lower support plate and the upper support plate), the central body of the sliding and dissipation shoe comprises a plastic sliding material, applied in the form of a layer or laminar film, having the function of promoting the relative sliding of the two surfaces.

In this way, the seismic isolation device is subject to the always quite high variability (sometimes up to 50%) of the friction characteristics of the laminar layer made of plastic material used, because such a layer is normally presented as a sheet, molded starting, as a state of the materials, from pre-mixed powders of various plastic components and providing, as a material, a base resin mixed with some plastic additives which increase its resistance and with others which promote its lubrication.

Examples of similar seismic isolators of the known sliding pendulum (single or double) type are known in patent documents WO2014/173622 A1 and WO2019/054302 A1 .

This means that the mechanical properties (e.g. tensile strength, elongation) are similar on average between one molded sheet and another, but the friction properties are not always kept constant especially under high load.

This situation often involves not only different slabs (from each of which the various sheets are obtained which, when applied to the central body of the sliding and dissipation shoe, constitute the laminar layer) but also the same slab, disadvantageously differentiating the behavior between sheets obtained from the center and from the edges of the slab itself.

Such discrepancies relative to design can be recognized or detected only during the experimental testing phase of the products at issue (seismic isolators) and thus once they are completed and theoretically ready for marketing when it is obviously too late relative to both the manufacturer's production needs and the purchaser's application needs (in this regard, it will suffice to mention the delivery time parameter, compliance with which is often fundamental or crucial in the presence of public building works assigned through a tender).

Currently, faced with such a situation, the manufacturers can only modify the dimensions of the individual laminar sliding layers of the shoe on a case by case basis and then proceed by reworking the metal components which act as supports (central body of the shoe), before the laminar layer - in the form of a sheet - is permanently coupled to them, with all the obvious disadvantages that this implies. On the contrary, where the application conditions expressly foresee a seismic isolator of the pendulum type provided with a friction coefficient either different or variable from zone to zone of the elevated structure, the present art known in the sector makes it possible to satisfy such a need only partially by providing as many seismic isolators (and as many respective mobile pendulums) as there are plastic material sliding laminar layers (in the form of sheets), different from one another for friction coefficients, of which they can be provided.

Substantially, at present, to obtain different friction coefficients for a given type of seismic isolators to be installed in a given application, it is necessary to design and produce as many different mobile pendulums and, as a consequence, as many different seismic isolators, to the disadvantage of logistic management (e.g. related to storage, transport and handling thereof) but above all to the disadvantage of application because the elevated structure is supported by seismic isolators which in every respective position introduce a fixed, constant friction coefficient, albeit different from that of the isolator of the adjacent position, and thus in some way variable in a more punctual manner and more localized in a given position.

Therefore, starting from the awareness of the aforementioned drawbacks of the background art, the present invention proposes to effectively and completely remedy them.

In particular, main purpose of the invention is to provide an improved friction seismic isolator of the so-called sliding pendulum type which allows the manufacturer to modify, or rather correct, the friction provided by a seismic isolation device during manufacturing in a simpler and more timely manner than in the background art.

In other words, it is primary purpose of the present invention to devise an improved friction seismic isolator of the so-called mobile pendulum type which makes it possible to satisfy certain and well-defined design choices, in terms of friction provided, in a more efficient manner than seismic isolators of known type.

It is a second purpose of the present invention to provide an improved friction seismic isolator of the so-called sliding pendulum type in which the mobile pendulum itself displays, comparing the multiple specimens in which it is produced, a uniform, common, constant, substantially equivalent or at least broadly comparable friction coefficient, and is thus capable of satisfying the design specifications even more effectively than the background art.

Within the scope of the aforementioned purposes, it is the task of the present invention to disclose an improved friction seismic isolator of the so-called sliding pendulum type which makes it possible to respect the customers’ needs - not least that of delivery time - in a significantly better manner than that offered by known seismic isolators.

It is a further purpose of the present invention to create an improved friction seismic isolator of the so-called sliding pendulum type which makes it possible to vary its friction coefficient in a more punctual and more localized manner than what can be obtained with seismic isolators of known type.

It is a last but not least purpose of the invention to provide a seismic isolator with improved friction and of the so-called sliding pendulum type, which makes it possible to satisfy a greater number of application requirements in a better and more effective manner, especially in terms of obtainable friction coefficient, while at the same time fulfilling the other above-mentioned objects it sets out to achieve. Said purpose are achieved by means of an improved friction seismic isolator of the sliding pendulum type as in claim 1 appended hereto, as hereinafter referred for the sake of brevity of exposition.

Further detail construction features of the improved friction seismic isolator and sliding pendulum type of the invention are contained in the related dependent claims.

The aforesaid claims, as hereinafter specifically and concretely defined, are an integral part of the present description.

Advantageously, the seismic isolator with improved friction and of the so-called sliding pendulum type of the invention allows the manufacturer, during production, to modify, or rather correct, according to needs the friction provided by a seismic isolation device in a simpler and more timely manner than in the background art. This by virtue of the fact that, from the design and initial production phase of the isolator of the invention, the movable pendulum is already conceived, generally at both side faces axially opposite each other along said longitudinal axis, with a plurality of superficial recess facing or facing outwards, within each of which sliding inserts made of plastic material having a high-friction coefficient are partially but stably housed.

Therefore, according to the technical teachings proposed by the invention, the manufacturer prepares, already in the design phase, a seismic isolator in which the mobile pendulum has the surface recesses already in correspondence of at least one of the two side faces, and subsequently applies the sliding inserts in some or all such surface recess, according to the customer’s needs; the result is an ability to ensure the uniformity of the friction properties of the various seismic isolators which are usually supplied and installed to dissipate, if necessary, the total energy transmitted, for example by an earthquake, to an elevated structure to which the seismic isolators are coupled more efficiently and more rapidly than in the background art, thus avoiding the typical problems not only of production but also of purchase management which can be found in the background art and mentioned above.

Indeed, by exploiting the invention, the manufacturer can select in advance the sliding inserts which substantially display the same friction coefficient, regardless of whether they are made of the same plastic material or not, and apply them subsequently in the respective surface recess of the mobile pendulum.

Equally advantageously, by allowing the manufacturer (contrary to the background art) to attribute the dissipative required properties simply, immediately and directly during the first production, the improved friction seismic isolator of the so-called sliding pendulum type of the present invention succeeds in satisfying the design choices more efficiently than the seismic isolators of known type.

More advantageously, the improved friction seismic isolator of the present invention allows to meet customer requirements - for instance and especially in relation to delivery times - better than known seismic isolators.

On the other hand, or consequently, in an equally advantageous way, the improved friction seismic isolator of the invention allows to diversify the friction coefficient by zones of the same mobile pendulum, indeed making it possible to vary such a friction coefficient not only from zone to zone of the elevated structure, as it happens in the prior art, but also in a more localized and punctual manner from zone to zone in the single seismic isolator concerned.

Therefore, by means of the invention, to obtain different friction coefficients for a given type of seismic isolators to be installed in an elevated structure, it is no longer necessary to design and produce as many different mobile pendulums and, consequently, as many different seismic isolators, as in the known art, but it is sufficient to set with accuracy the application of the sliding inserts (or discs) in the surface recess, e.g. leaving one or more of them free.

Substantially, to obviate the drawbacks of the background art, in particular the time-consuming losses and costs associated with the reworking of the mobile pendulum mentioned above, the solution identified by the invention consists in the use of a mobile pendulum of the so-called "multi-coupling" type, i.e. comprising a plurality of sliding couplings (or discs) applied to the central body of the lenticular element (mobile shoe) of the seismic isolator.

In this manner, by means of the invention, in at least one of the side faces of the mobile pendulum, some superficial spaces (or grooves) are available in which it is possible to apply sliding discs made of frictional plastic material not necessarily obtained from the same plate and/or manufactured with the same plastic material; to calibrate the friction, it will be sufficient to insert more or less sliding inserts in the respective surface recess (which, therefore, are not all necessarily occupied by sliding inserts) or, preferably, to use sliding inserts with different friction coefficients (and therefore coming from different sheets of the same plastic material or different plastic materials) applied onto the same convex external face, of contact and sliding, of the mobile pendulum.

Said objects and advantages will be more evident from the description that follows, related to a preferred embodiment of the improved dissipative friction seismic isolator of the mobile pendulum type of the invention, given by way of indicative and non-limiting example, with the help of the attached drawings, in which: figure 1 is a cutaway assonometric view of the improved friction seismic isolator of the mobile pendulum type of the invention, in the equilibrium position;

- figure 2 is a cutaway view of a detail in figure 1 .

The improved dissipative friction dissipation seismic isolator 1 of the mobile pendulum type, object of the present invention, is shown in an operative condition in figure 1 , in which it is indicated as a whole by reference numeral 1 .

As it can be noted, such a dissipative seismic isolator 1 comprises: a lower plate 2 adapted to be arranged close to a foundation structure (also commonly known as a "substructure", not shown); an upper plate 3 arranged above said lower plate 2 along a longitudinal axis Y and adapted at least to contribute to supporting an elevation structure (commonly also known as “superstructure”, not shown) to dissipate the kinetic energy transmitted to the elevation structure itself by a natural phenomenon or by a human-caused event and provided with a high release of total energy; a mobile dissipation pendulum 4 arranged in simple support against the lower plate 2 and the upper plate 3 between which it is interposed in such a way as to swing freely on an inner surface 2a, 3a of the lower plate 2 and the upper plate 3 according to one or more random side directions (generally radial), orthogonal to the longitudinal axis Y, alternately between an equilibrium position, taken in absence of the natural phenomenon or the human-caused event, in which the mobile dissipation pendulum 4, the lower plate 2 and the upper plate 3 are substantially coaxial to each other, and a plurality of instability positions, taken while the natural phenomenon or the human-caused event is in progress, in which the mobile dissipation pendulum 4, the lower plate 2 and the upper plate 3 are offset from each other, to dissipate the kinetic energy of the natural phenomenon or the human-caused event, transmitted to the elevation structure.

According to the invention, the mobile pendulum 4 has, in the described preferred example, at both the two side faces 4a, 4b axially opposite each other along the aforesaid longitudinal axis Y, a plurality of surface recesses 5 facing towards the outside, inside each of which, in this case, sliding inserts (or discs) 6 made of high friction coefficient plastic material are partly housed.

In detail, both the lower plate 2 and the upper plate 3 are made of a metallic material, such as structural steel (or construction steel) carbon steel, preferably type S355 (also identified with the code Fe 510) according to the classification adopted by the UNI EN 10025 - 95 standards (the number to the right of the S indicates the characteristic yield strength, expressed in MPa).

Therefore, substantially, as a function of what has been highlighted above, said surface recess 5 are not less in number than said sliding inserts 6.

More in detail, where present, the sliding inserts 6 are stably and irremovably coupled to the mobile pendulum 4 at the housing recess 5 (in which they are partially inserted) through any one of the stable union means chosen by the group consisting of snap coupling means (for instance of the bayonet or dovetail type), interlocking means, mechanical fastening means (such as for instance screws/nut screws), locking means (nut/bolt/washer), adhesive substances and so on. Preferably but not necessarily, the surface recesses 5 are uniformly distributed on both side faces 4a, 4b of the mobile pendulum 4 in this case.

By way of a preferred, indicative but not limiting example only, each of the surface recesses 5 has a circular profile with which, inevitably, the profile of each of the sliding inserts 6 is combined, which are thus presented under the preferred form of discs.

Based on what has been described above, it can be inferred that the sliding inserts 6 are protruding, in the specific case, from both of the aforementioned side faces 4a, 4b of the mobile pendulum 4, as it can be better derived from the appended figure 2.

Preferably but not mandatorily, each of the sliding inserts 6 has a thickness of a value comprised in the 2-10 mm range.

More particularly, the thickness of each of said sliding inserts 6 has a value in the 4-8 mm range; even more preferably, the thickness of each of said sliding inserts 6 is 7 mm.

Additionally, each of the sliding inserts 6 presents an outer surface 6a, facing the inner surface 2a of the lower plate 2 on one side and the inner surface 3a of the upper plate 3 on the other side, having a profile with convexity which mates with the concavity of the profile of the inner surface 2a, 3a of the lower plate 2 and of the upper plate 3, respectively, according to an advantageous construction practice.

According to the preferred embodiment described herein of the invention, the plastic material of the sliding inserts 6 is a thermoplastic resin or a thermosetting resin.

More particularly, the thermoplastic resin is any of the plastic materials chosen from the group consisting of polytetrafluoroethylene (commonly known by the acronym PTFE), ultra-high molecular weight polyethylene (commonly known by the acronym UHMWPE), polyoxymethylene (commonly known by the acronym POM), polyamides (commonly known by the acronym PA) and/or combinations thereof in varying proportions.

In turn, the thermosetting resin is any of the plastic materials chosen from the group consisting of phenolic resin, amide resin, epoxy resin, polyurethane resin, unsaturated polyester resin, silicone resin, alkyl resin and/or combinations thereof. Preferably but not exclusively, the friction coefficient of the plastic material of the slide inserts 6 is different for at least two of said slide inserts 6.

Furthermore, in this specific and preferred case, the plastic material with which the sliding inserts 6 are made is different for at least two of said sliding inserts 6, an aspect which automatically determines differences (albeit minimal) in the relative friction coefficient; it remains, however, understood that, in other embodiments of the invention, not shown, the different friction coefficient in the various concerned zones of the mobile pendulum can be obtained also by means of sliding inserts made of the same plastic material, e.g. because they come from different sheets of the same plastic material, as already noted above.

Providing a plastic material having a different friction coefficient also for only two of the sliding inserts 6 - even though said plastic material could possibly be the same for the sliding inserts 6 themselves - allows to broaden, relative to the background art, the range of coefficients of friction values which can be obtained by means of the seismic isolator with improved friction and of the sliding pendulum type of the invention.

In other words, by means of the constructive device described above - the difference in the friction coefficient of the plastic material of at least two of the sliding inserts 6 -, the improved friction seismic isolator of the sliding pendulum type of the present invention makes it possible to obtain a more varied and wider range of values of the average friction coefficient than the one that can be obtained with seismic isolators of the sliding pendulum type currently available on the market while maintaining the same functional efficiency.

The central body 7 of the mobile pendulum 4 is made, as with the base plate 2 and the upper plate 3, of a metallic material, e.g. also structural (or construction) carbon steel, preferably always of class S355 (also identified by the abbreviation Fe 510). In a preferred but not limiting manner, the inner surface 2a, 3a of the lower plate 2 and the upper plate 3 respectively is coated with a laminar cap 8 made of a metallic material, polished to a mirror finish and having a roughness, normally expressed in R z (which provides, in practice, a measure of the maximum irregularity of a surface averaged over five peaks and five valleys), of less than 1 . The laminar cap 8, visible in figure 1 , is made, for example, of stainless steel and is formed from flat metal sheet - normally 2.5 mm thick.

Preferably, but not necessarily, the laminar cap 8 is simply inserted into an annular seat, not visible in the accompanying figures, obtained in the inner perimetrical edge 2b, 3b respectively of the lower plate 2 and the upper plate 3 and assumes a convex conformation with the concavity facing the mobile pendulum 4.

In practice, the laminar cap 8 is not rigidly fixed to the respective steel plate 2, 3 (substantially, it is not screwed, welded, glued or, more generally, rendered immobile) but simply inserted in a sort of annular pocket obtained in the inner perimetrical edge 2b, 3b of the lower anchor plate 2 and the upper striker plate 3, providing for calibrated geometries and spaces, in which it is left free to deform; this avoids the possible problems of buckling (or bending) of the laminar cap 8 during the swinging movement of the pendulum isolator 1 of the invention.

It is understood that other optional embodiments of the improved dissipative friction seismic isolator of the mobile pendulum type of the invention, not shown in the following figures, could provide that only one of either the lower plate and the upper plate is coated with a laminar cap made of a metallic material, polished to a mirror finish.

By virtue of the description just given, it is, thus, understood that the improved friction seismic isolator of the sliding pendulum type, object of the present invention, achieves the objects and reaches the advantages already mentioned. Upon execution, changes could be made to the improved dissipative friction seismic isolator of the mobile pendulum type of the present invention consisting, for example, in a mobile pendulum which, unlike what previously described and illustrated in the accompanying figures, presents surface recesses only at one of the two side faces axially opposite each other along the longitudinal axis of the mobile pendulum. It follows that the improved dissipative friction seismic isolator of the mobile pendulum type of the present invention could include, in further alternative embodiments, sliding inserts on only one of these two side faces of the sliding pendulum, in a number varying from a minimum of two to a maximum of as many as the recesses set on at least one of the two side faces of the sliding pendulum. Furthermore, there may be other embodiments of the invention, not shown in the accompanying drawings, in which the improved dissipative friction seismic isolator of the mobile pendulum type claimed herein comprises a number of intermediate mobile pendulums greater than one, typically two, to constitute a seismic isolator of the double sliding pendulum type, which does not affect the advantage brought by the present invention.

Additionally, in other embodiments of the improved dissipative friction seismic isolator of the mobile pendulum type of the invention, not yet shown, the mobile pendulum may comprise a laminar template coupled, by means of joining means, to at least one of its two side faces axially opposite each other, and having a plurality of surface recess (possibly passing through the thickness of the laminar template) facing or facing outwards, adapted to stably accommodate therein the respective sliding inserts made of high-friction coefficient plastic material; again, in this case, only some (from a minimum of two) or all the surface recesses may be equipped with the respective sliding insert.

Finally, it is apparent that many other changes could be made to the improved friction seismic isolator of the mobile pendulum type concerned, without departing from the principles of novelty inherent in the inventive idea, just as it is apparent that in the practical implementation of the invention, the materials, shapes and sizes of the details shown may be any according to the needs and may be replaced by other technically equivalent elements.

Where the constructive features and techniques mentioned in any successive claims are followed by references signs or numerals, such reference signs were introduced with the sole aim of increasing intelligibility of the claims themselves and consequently, such reference signs have no limiting effect on the interpretation of each element identified by way of example only by such reference signs.