Technical Field As indicated by its title, the invention herein has the objective to improve the existing fences and walls that keep the public that goes to watch any sport game match apart from the field where the game takes place and apart from the players, arbitrators, coaches, technical personnel, journalists, etc., that stay inside or around the game field.

Background Art It is currently used in the practice to separate the people that go to the stadiums or gymnasiums to watch the games from the game field itself in some sports where a great crowd gets together, to avoid such people access to the field where the game is taking place. The considerations to this practice are very well known and we can briefly summarize them in: a) The necessity of keeping the match beginning time.

Effectively, if we consider a soccer game that shall be broadcasted a live on the television using a satellite, the transmission schedule must be strictly respected either due to the costs involved, or to the set international commitments of which non-accomplishment may derive the satellite broadcasting interruption due to time expiration prior to the match end, with high costs and in some cases with agreement penalties. b) The necessity of keeping the physical integrity of the players, arbitrators, and other personnel directly involved such as joumalists and technical staff.

In this case no comments are needed facing the continuous news about the aggressions suffered by the players and arbitrators. Such aggressions are performed through strikes, objects thrown from the audience to the field, including other misbehaviors from the public.

c) The necessity that various matches in the same championship, having the same starting time, indeed begin at the same time. This must happen to avoid the possibility of granting advantage to the some team, in the case of one match begins later than the others. When the teams are disputing games in a championship and the results are known beforehand, it may jeopardize ones despite of others, since they can implicate in aprioristic ascension or defeat prior to the end of the matches.

To prevent and avoid such things, it can be used holes or trenches in the ground, walls, fences, barriers, and etc., to create obstacles that shouldn't be trespassed by the watchers.

The perimeter holes around the playing field are not always possible due to space or costs reasons. It is not always that there is room at the stadiums or gymnasiums to dig a trench around the playing field. At the same time, such trenches may disturb or even make it impossible when some specific sports are supposed to take place in the said stadiums or gymnasiums such as athletism, cyclism, runnings, etc., that in general can be practiced around the perimeter of such playing field. In this case, the trenches or ditches would take such area at least partially and would collect al sort of trash and rain water and its cleaning would generate additional costs.

The walls and fences are resources widely applied. We can quote two kinds: the fences made of a metal wire net and the vertical walls made of transparent material.

The fences made of metal wire nets or metallic gauzes attached to posts vertically berried in the ground around the entire perimeter of the playing field have an inconvenient: the watchers may climb the metal wire nets, no matter the height, and invade the playing field. They can also climb it to sit over it for a better view of the game.

The walls made of flat, transparent and resistant panels are also

applied. These walls solve the playing field invasion problem, since the regular height (7 meters) prevent them to be trespassed, but their inconvenient consist in, besides diminishing the air circulation they prevent the fireman, when the occasion demands, to use the water hoses from the middle of the playing field, or the police force to terminate fights through gas launches. On the other hand, their costs are too high and demand an expensive cleaning and maintenance of the surfaces.

Object of the Invention It is the main object of this invention to create a barrier that is not possible to be trespassed by the public, avoiding it to be climbed to its top at the same time that it permits the air circulation ; It is another object of the invention that this perimeter barrier allows the fireman and the police force to use the water hoses, the gas launchers and other effective means through the said barrier ; It is another object of the invention that this barrier is composed of modular sets of easy maintenance and repair, with an approximate length of 2 and 3 meters each one, in a way that if a piece breaks it does not deteriorate all the barrier; and The last object of this invention is that no part of the upper half of the said barrier presents a protrusion, grave, step or any other mean that enables it to be climbed up to its top by the public.

Brief Description of the Invention Improvement in fences and security walls for sport fields in general, comprehending a plurality of posts or solid vertical elements coming from the floor, regularly spaced apart and disposed at least around part of the perimeter of the playing field, separating the public from the said playing field, having between each pair of posts an area of metal wire net or metallic gauzes, characterized by the fact that between each pair of first and second vertical posts is disposed a transversal rod perpendicular to said first and second vertical posts and disposed at an intermediate height between

the floor and the top end, defining inside these first and second vertical posts, the transversal rod and the floor, a frame in which is fixed and held a portion of metal wire net or metallic gauze from its four sides, being said metal wire net or metallic gauze fixed and held between these first and second vertical posts independently from the portions of metal wire net or metallic gauzes disposed and individually fixed and held to third vertical posts immediately adjacent to the first and second vertical posts, being the perpendicular rods disposed between one of the said first and second vertical posts and one third vertical post, substantially at the same height from the floor and independent one from the other in relation to the said post; over each one of the said perpendicular rods is disposed between each pair of first and second vertical posts a panel substantially flat and made of a transparent material which goes from the perpendicular rod to the top ends of said vertical posts, presenting such posts, panels and rods even surfaces without any graves or protrusions; determining the said wall bottom part of metal wire net or metallic gauze a zone of air and/or gas free circulation, and the top part of the wall determining a containing barrier of gases and an induction of ascendant air stream.

Brief Description of the Drawings Based on the said combination, various are the embodiments that can be materialized, but in order to realize the advantages described herein and those the users can aggregate to it, and to easy the comprehension of the constructive and functional characteristics of the present invention, it is described a preferred embodiment in the following pages, clarifying that it is a mere example and in no way infers a restrictive character to the range of protection of the present invention patent. It has only a finality of exemplify and illustrate the basic conception on which it is founded.

Fig. 1 shows a top perspective view of part of the perimeter of a generic playing field, as well as a soccer goal net protected by the barrier wall of the present invention;

Fig. 2 shows a cross section of a schematic tribune zone and of the barrier wall of the invention where it is illustrated the effect of temporary accumulation of gazes and the induced air stream; Fig. 3 shows an enlarged detail of this barrier wall in perspective.

Disclosure of the Invention In the quoted drawings the same references identify the same components and means illustrated therewith.

A first post (1) and a second post (2), between posts (1) and (2) is disposed at an intermediate height to both and parallel to the floor, a rod (3), which can eventually completed by a rod (4) to the floor, defining a frame in which is fixed and held at its inside area a metal wire net or metallic gauze (5), such metal wire net or metallic gauze area (5) is attached to its frame and fixed to itself in an individual way in relation to the adjacent areas (5), it means that the net is not continuous and covers only the area inside each frame defined this way. This allows a quick change in a damaged modular unit, without having to disassemble the adjacent parts, nor affect their nets.

Over each rod (3) is disposed between each pair of posts (1) and (2) a flat panel (6) made of a transparent material, such as an acrylic, laminated glass or polycarbonate panel.

The posts and the rods present even surfaces that are rounded shape without leaving any graves or protrusions with rounded edges. Fig. 2 shows how is possible to make water and/or gases pass through the zones (5) to the tribune, and a gas cloud such as tear gas is initially retained and concentrated by the wall panels (6), for a short period of time, allowing its dissuasive effect to be incremented. By its time, employing the known principium that all wall having an open area at the bottom side and placed against an horizontal air stream, induces to an ascendant column of circulating air, the arrows (8) symbolize such air stream that, according to the wind direction, dissipate in one sense or the other the said gas cloud from its short stay.

In Fig. 3, it is illustrated as (5") metal wire nets or metallic gauzes of various patterns and compositions to illustrate that the nets can have a wider or narrower stitches in various conformations.

It is evident that this wall barrier can be placed around all the perimeter of the playing field or fencing only part of the same.

In its turn, the transparent panels (6) besides allowing a sharp view to the watchers, prevent from the tribune that object are thrown at the field and at some selective places to affix sponsors advertisements without disturbing the publics view of the field and the players.