IT202100015236A1 - IMPROVED TYPE SMOKE AND HEAT EVACUATOR - Google Patents

Description

IMPROVED TYPE SMOKE AND HEAT EVACUATOR.

DESCRIPTION

The invention relates to a smoke and heat evacuator suitable for installation in buildings to evacuate smoke and heat from the premises in the event of a fire.

A smoke and heat evacuator that follows for simplicity? descriptive we will simply indicate with the word ?evacuator?, it essentially comprises a lid delimited on the perimeter by a frame and made of metallic or non-metallic material which, by means of hinges ? connected to a counterframe that delimits a base around the perimeter.

The base, also preferably made of metal, delimits the perimeter of a through opening made in the structure of a building and communicating with the external environment. The installation of evacuators in buildings? required by current safety standards which also prescribe that in the event of fire, the lid opens automatically and within a predetermined time.

According to the prior art, the lid ? normally placed in the closed position with the frame facing the base counterframe and ? mechanically connected to handling means which include one or more? connecting rods and a gas actuator which, in the event of a fire, is fed with pressurized carbon dioxide (CO<2>) to open the lid almost immediately. instant.

In particular? Carbon dioxide? contained in a can having the delivery mouth connected to the supply line of the pneumatic actuator and sealed by a breakable membrane.

When special sensors installed in the environment detect the presence of smoke or an increase in temperature beyond a pre-set threshold, a special actuator pierces the membrane so that the carbon dioxide flows from the can to the gas actuator causing the lid to open.

According to an embodiment of the prior art, the perforation of the membrane is produced by an actuator actuated by an explosive microcharge which is triggered by the Joule effect by a remotely powered electrical resistance.

According to another embodiment also belonging to the prior art, the perforation of the membrane is produced by an actuator which is actuated by preloaded elastic means when these are released by the breakage of a thermosensitive phial.

Both of the known embodiments cited have for? some recognized drawbacks which are briefly listed below.

As regards the embodiment which provides for the use of an explosive microcharge, it has the drawback that in some cases the opening of the lid of the evacuator could occur completely accidentally.

In fact, the electrical device that triggers the explosive microcharge? very sensitive to atmospheric discharges, to induced currents and to radiofrequency disturbances present in the environment and in some circumstances this could cause the ignition of the explosive microcharge and therefore the undesired opening of the vent cover.

Another drawback? constituted by the fact that to carry out the periodic verification of the efficiency of the opening system of the cover of each evacuator ? necessary to detonate an explosive microcharge or intentionally destroy a heat-sensitive vial.

because the cost of the maintenance technician who carries out the intervention must be added to the cost of the explosive micro-charges and the heat-sensitive vials which are sacrificed, it is understood that every periodic check of efficiency is economically burdensome especially if in the building? installed a large number of evacuators.

An additional drawback? due to the fact that after each periodic efficiency check, the operators are forced to reach each evacuator, usually installed on the roof of the building and therefore in an awkward position to reach, to replace the explosive micro-charges or the heat-sensitive ampoules.

Not the least drawback? also constituted by the fact every time that the? user has need? to deliberately open the lid he must carry out the manual intervention or proceed with an automatic activation which involves the destruction of an explosive microcharge or of a thermosensitive phial with the relative CO2 or nitrogen cylinders.

In the case of opening systems that use heat-sensitive vials, to avoid having to detonate the explosive microcharge at each intentional opening of the evacuator cover, suitable electromechanical solenoid means have been devised which are installed in each evacuator and which allow the operator to reset it after opening the lid of the evacuator.

Devices of this type have high costs for the construction of the plant to which must in any case be added the cost for the intervention of the maintainer.

Notwithstanding the limitations and drawbacks that have been listed, all the opening systems of the evacuators mentioned? said present for? the advantage of having a great reliability? of operation that guarantees almost? complete opening of the cover of the skylights in case of fire.

However, the current state of the art in the sector sees the majority of manufacturers oriented towards the replacement of gas actuators fed by CO<2 > or pressurized nitrogen, with linear electric actuators where each actuator includes an extendable stem which is set in motion by kinematic mechanisms associated with an electric motor.

The use of linear electric actuators in place of gas actuators powered by CO2 or nitrogen provides that the electric motors that operate the actuators are powered in low voltage with batteries connected in buffer to the electric power line.

AND? understandable that the manufacturers of evacuators are oriented towards using linear electric actuators of the type mentioned considering that their use in place of gas actuators powered by pressurized CO2 allows a more? simple execution of the evacuators and also a simplification of the plant which only requires the execution of an electric power line for the electric motors which move the stems of the actuators.

In the known embodiments of evacuators which use linear electric actuators, the? of the stem? connected directly to the cover frame and this entails the drawback that the manufacturer must use actuators with a greater stroke of the rod and therefore with rods of increasing length and increasing cost as the size of the cover increases measured according to the thrust direction of the actuator .

Furthermore, the need having to use actuators with rods of increasing lengths involves for the manufacturer the?impossibility? to standardize the electric actuators to be used by limiting their number.

The present invention intends to overcome all the aforementioned drawbacks by providing an evacuator which uses a single linear electric actuator having the stem of a single length and stroke regardless of the size of the lid measured according to the thrust direction of the actuator.

The purpose ? achieved with the construction of the improved smoke and heat evacuator according to the main claim to which reference will be made reference.

Other characteristics of the invention are disclosed in the dependent claims.

Advantageously, the evacuator with electric actuator of the invention allows the use of linear electric actuators having stems of shorter length and therefore lower cost than linear electric actuators which are applied to evacuators of the prior art of equal dimensions. Still advantageously, the invention makes it possible to standardize the system for moving the lid of the evacuators by using for all the lid sizes a single electric actuator having a stem of a single length and stroke.

This also entails the further advantage of being able to unify the types and sizes of the carpentry elements which connect the electric actuator and the lid opening and closing lever mechanisms and to the other elements which make up the evacuator.

The purposes and advantages listed above will be better highlighted during the description of a preferred embodiment of the invention which is given hereinafter by way of example but not as a limitation, with reference to the attached drawings where:

- in fig. 1 shows the smoke and heat evacuator of the invention in an axonometric view and in the open position;

- in figures 1a and 1b two enlarged details of fig. 1;

- in fig. 2 shows a front view of the evacuator of fig. 1 placed in the closed position;

- in fig. 3 shows a side view of the evacuator of fig. 1 placed in the closed position;

- in fig. 3a shows an enlarged detail of fig. 3;

- in fig. 4 shows the evacuator of fig. 3 in slightly open position;

- figures 5 to 9 show the evacuator of the invention in different open positions;

- in fig. 10 shows a front isometric view of the evacuator of the invention in the partially open position; - in figures 10a and 10b two enlarged details of fig.

10.

The smoke and heat vent of the invention ? represented in overall view in figures 1 to 10 where ? indicated as a whole with 1.

Furthermore, figures 1a, 1b, 3a, 10a, 10b show enlarged details of the evacuator represented in the overall views of figures 1 to 10.

With particular reference to figure 1, it can be observed that the smoke and heat evacuator 1, which hereinafter for simplicity? descriptive we will indicate only with the term ?evacuator?, comprises a base 2 delimited by a counter frame 3 and arranged peripherally to a through opening 4 made in the structure of a building and a lid 5 delimited by a frame 6 associated with the counter frame 3 of the base 2 by hinges 7.

The through opening 4 connects one or more? rooms of the building with the external environment and in the event of fire, the hinges 7 allow the lid 5 to be opened by rotation to allow the evacuation of smoke and heat.

For this purpose, the evacuator 1 ? provided with rotation means 10 of the cover 5 which can be seen particularly in figure 2 and in the subsequent figures from 3 to 10 and which comprise a linear electric actuator 11, which for simplicity? below we will simply indicate with the term ?actuator 11? having a drive unit 11a which sets a rod 12 in linear motion inside a cylinder 13.

The rotation means 10 also comprise an articulation unit 14 operatively connected to the actuator 11 and comprising at least one first rod 15 visible particularly in figures 3 to 9 which connects the head 16 of the stem 12 of the actuator 11 to the counterframe iella 3 of the base 2 and at least one second rod 17 which connects the cylinder 13 to the counterframe 3 of the base 2.

Preferably, but not necessarily, to ensure good stability? during movement, the embodiment of the articulation unit 14 described provides for the presence of two first rods 15 side by side and parallel to each other and two second rods 17 also side by side and parallel to each other.

According to the invention, the articulation unit 14 also comprises at least one connecting rod 18 which connects the head 16 of the stem 12 to the frame 6 of the lid 5.

To ensure good stability during movement there are two connecting rods 18 side by side and parallel to each other.

In particular, it can be observed that each connecting rod 18 has the first end? 18a pivoted to the head 16 of the stem 12 of the actuator 11 and the second end? 18b pivoted to the crossbar 22 of the lid 5 which ? included and ? fixed between two mutually opposite sides 6a, 6b of the frame 6 which peripherally delimits the lid 5.

As far as the first rods 15 and the second rods 17 are concerned, it can be observed that each first rod 15 has the first end? 15a pivoted to the head 16 of the rod 12 of the actuator 11 while each second rod 17 has the first end? 17a pivoted to cylinder 13.

Furthermore, the second end? 15b of each first rod 15 and the second end? 17b of each second rod 17 are both connected to the counter chassis 3 being pivoted to a support bracket 19 which belongs to the cross member 20 of the counter chassis 3 which ? understood and fixed at the ends? of two mutually opposite sides 3a, 3b of the counterframe 3 of the base 2.

It is also observed that the second extremity? 15b of each first rod 15 and the second end? 17b of each second rod 17 are pivoted in separate points of the support bracket 19.

In particular the second end? 17b of each second rod 17 ? disposed within the area delimited perimetrically by the base 2 and located below the plane X defined by the upper surface 3c of the subframe 3 and the second extremity? 15b of each first auction 15 ? arranged above the aforementioned plane X defined by the upper surface 3c of the counterframe 3.

Furthermore, the second end? 15b of each first rod 15 and the second end? 17b of each second rod 17 are aligned according to a direction Z inclined with respect to a vertical direction and incident on the plane X defined by the upper surface 3c of the subframe 3.

Finally, it can be observed that the articulation unit 14 also comprises at least a third rod 21, in the embodiment described two third rods 21 side by side and parallel to each other, each of which connects a first rod 15 and a second rod 17 to each other corresponding and in each third rod 21 are identified a first end? 21a pivoted in an intermediate area of the first rod 15 and a second end? 21b pivoted in an intermediate area of the second rod 17.

In this way the actuator 11 and the articulation group 14 are kinematically connected to each other and when the actuator 11 is operated, they cooperate with each other to rotate the lid 5 as it will be? shown below by referring to the figures.

The evacuator 1 also comprises hooking means 30 which are configured so as to lock the cover 5 to the counterframe 3 when the linear electric actuator 11 is ? in rest state and the frame 6 which delimits the lid 5 ? arranged facing and in contact with the counterframe 3 of the base 2 as can be seen in figure 3.

Furthermore, the hooking means 30 are configured to also be able to open the lid 5 after releasing the counterframe 3 which takes place automatically when the actuator 11 is operated, how will it be? below more described in detail.

It can be observed that the coupling means 30 comprise a rotating rod 31 also visible in the detailed figure 1b, associated with the lid 5 by means of support means, not indicated in the figures and supported by the frame 6, to which one or more elements are fixed. hooking bolts 33 which therefore rotate rigidly with the revolving rod 31 when this is rotated along its longitudinal axis.

In the particular embodiment that is described and as can be seen in figures 1 and 10, the hooking bolts 33 are three in number and two of them are arranged at the ends? to the revolving rod 31 while one? instead arranged in an intermediate position to the rotating rod 31 itself and can be observed in figure 1b.

In another embodiment, the hooking bolts 33 could be in any number and arranged in any position along the revolving rod 31.

There are also coupling bolts 34 belonging to the counterframe 3 of the base 2 which are configured to cooperate with the coupling bolts 33.

In the end ? there is a tie rod 35 which connects the rod 31 to an operating lever 36 associated with the lid 5 and visible in figure 1a, which? configured to operate the tie rod 35 and release the hooking bolts 33 from the hooking bolts 34 when the thrust of the head 16 of the stem 12 of the actuator 11 acts on the operating lever 36 and causes it to rotate as shown in figure 4.

In fact, as can be clearly seen in fig. 1a, the operating lever 36 ? rotatably associated with the lid 5 through a rotation pin 39a which constrains it to a fixed support 42 fixed to the cross member 22 of the lid 5 itself.

Furthermore, the operating lever 36 ? provided with an abutment surface 40 for contact with the head 16 of the stem 12 of the actuator 11 as can be seen in particular in figure 4.

It can also be observed, particularly in the figures from 3 to 9 and in the detail figure 1b, that the tie rod 35 has the first end 35a fixed to a projecting coupling 37 belonging to the rotating rod 31 and the second end? 35b fixed to the operating lever 36 by means of a fork 38 and a through pin 39.

The extremities? of the tie rod 35 can be connected to the revolving rod 31 and to the operating lever 36 also by means different from those described.

When the cover 5 ? in the closed position as can be seen in figure 3, if the head 16 of the stem 12 of the actuator 11 contrasts with the abutment plane 40 of the operating lever 36, the thrust produced by the actuator 11 generates, with respect to the rotation pin 39a, a torque which causes the operating lever 36 to rotate around the rotation pin 39a and puts the tie rod 35 into traction.

The traction of the tie rod 35 in turn causes the rotation of the rod 31 around its own longitudinal axis and of the hooking bolts 33 connected to it which release the respective counterbolts 34 allowing the incipient opening of the lid 5 as can be seen in figure 4 .

Also associated with the revolving rod 31 are elastic means 41 visible in particular in figure 1b which are configured to make the rotation of the revolving rod 31 elastic so that the hooking bolts 33 spontaneously snap the hooking bolts 34 when the lever maneuver 36 ? free from contact with the head 16 of the stem 12 of the actuator 11 and the frame 6 of the cover 5 is lowered and faces the counterframe 3 of the base 2 in the position shown in figure 3.

Preferably, but not necessarily, the elastic means 41 comprise a cylindrical spring 41a wound externally to the rotating rod 31 and having one end? fixed to the same revolving rod 31 and the end? opposite arranged in contact with the crosspiece 22 of the cover 5.

In particular, it can be observed in figures 1, 1a, 1b and 10 that the elastic means 41, the tie rod 35 and the operating lever 36 are associated with the cover 5, being arranged and connected to the crosspiece 22 comprised between two mutually opposite sides 6a, 6b of the frame 6 which peripherally delimits the lid 5.

Operatively, with reference to figure 3 which represents the lateral section of the evacuator 1 with the cover 5 arranged in the closed position, it can be observed that the head 16 of the stem 12 of the actuator 11? distanced from the abutment plane 40 of the operating lever 36 and the hooking bolts 33 are hooked to the respective hooking bolts 34 as can be seen in figure 3a and are kept in the hooked position by the elastic torsion which the cylindrical spring 41a exerts on the revolving rod 31.

In this configuration the cover 5 ? and remains permanently closed. If the actuator 11 is actuated, when the head 16 of its stem 12 comes into contact with the abutment plane 40 of the operating lever 36, this rotates around the rotation pin 39a and sets the tie rod 35 in traction.

The traction applied to the tie rod 35 overcomes the elastic force of the cylindrical spring 41a and rotates the revolving rod 31 which causes the coupling bolts 33 to separate from the respective counterbolts 34 and the incipient opening of the lid 5.

From this moment the lid 5, no longer? hooked to the subframe 3, pu? be opened by the movement of the stem 12 of the actuator 11 passing through all the configurations shown in figures 4 to 8 and up to the maximum opening configuration corresponding to an angle of about 158? represented in figure 9.

AND? It is important to note that when the rod 12 is withdrawn from the cylinder 13, the actuator 11 increases its length and the articulation unit 14 imposes a clockwise rotation on the actuator 11 which leads it to progressively assume all the different positions shown in the figures from 3 at 9.

During these movements, the head 16 of the stem 12 of the actuator 11 compresses the connecting rod 18 axially, which being rigid and non-deformable and forming with the crosspiece 22 of the cover 5 a

corner ? always less than a flat angle, starting from the configuration shown in figure 3, ? forced to rotate rigidly counterclockwise by moving its second extremity? 18b upwards up to the configuration represented in figure 7 in which the lid 5 is? open in a substantially orthogonal position to the base 2.

In this way its second extremity? 18b, being connected to the crosspiece 22, applies a thrust to the lid 5 which lifts it by rotation around the hinges 7.

In addition to the operational description given above, for the correct explanation of the invention and to illustrate the achievement of the aims of the invention, reference is made to figures 5 to 9 which illustrate the elongations of the stem 12 of the actuator 11 for different lid opening angles 5.

In particular, figures 5 to 9 compare, for some opening angles of the lid 5 equal to each other, the elongations C of the stem 12 in the case of the invention in which its head 16 is? connected to the crosspiece 22 through the connecting rod 18, with the elongations C? which would occur if the actuator rod, schematically represented with the large discontinuous line, had the head 16? connected directly to the crosspiece 22 as happens in the evacuators of the prior art.

Basically in figures from 5 to 9 a comparison is made between the values of the elongations C and C? respectively in the case of the invention in which the head 16 of the stem 12 ? connected to the crosspiece 22 through the connecting rod 18 and the known art, represented with a thick discontinuous line, in which the head 16 of the rod ? directly connected to the crosspiece 22.

Passing from the configuration shown in figure 5 which corresponds to an opening angle of the lid 5 of approximately 45? in which the stretches C and C? of the stems are substantially equal to each other, at the configuration of figure 6 and up to the final configuration of maximum opening of about 158?, it can be observed that the elongations C? continue to increase significantly with respect to C elongations.

This shows that if the head 16? of the actuator stem were connected directly to the crosspiece 22 of the cover 5, it would be necessary to use an actuator with a longer stem and therefore of greater dimensions and more? expensive compared to what is used in the evacuator 1 of the invention.

For? ? it is also of fundamental importance to take into consideration the presence of the third rod 21 which connects the first rod 15 and the second rod 17 to each other.

In fact, it can be observed in the figures that the lengthening of the stem 12 of the actuator 11 causes the clockwise rotation of the first rod 15 and of the second rod 17 since they? the third rod 21 which connects them makes them both rotate clockwise with respect to the respective second ends? 15b and second end? 17b.

In this way the rotation of the second rod 17 causes the progressive lifting of the actuator 11 which in the absence of the third rod 21 would not instead be raised with respect to the initial position of figure 3 when the cover 5 is? closed.

Therefore, in order to reach the openings shown in figures 4 to 9, it would be necessary to use an actuator having an extremely smaller stem. long and therefore much more? cumbersome and above all much more? expensive compared to what you can instead? use in the evacuator 1 of the invention due to the presence of the third rod 21. Therefore, in the evacuator 1 of the invention the connecting rod 18 and the third rod 21 interact operatively during the stroke of the rod 12 of the actuator 11 and create a synergy which allows , compared to the known art and on equal terms? of opening angles of the covers, to significantly reduce the stroke of the rod of the actuator being used.

Consequently, smaller, less bulky and also less expensive actuators can be used, thus achieving the object of the invention.

AND? also important to note that the articulation group 14 ? been sized so that when the lid 5 ? open at an angle of about 45? as can be seen in figure 5, the second rod 17 is arranged in a substantially horizontal direction and the actuator 11 is instead arranged in a substantially vertical direction.

In this configuration, the head 16 of the stem 12 ? disposed in the limit-condition in which it ? in contact with the operating lever 36 and exerts the maximum lifting thrust of the lid 5 directly on the crossbar 22.

Exceeded the? Opening angle of about 45? the head 16 of the stem 12 separates from contact with the operating lever 36 as can be seen for example in figure 6 and the connecting rod 18 transmits to the cross member 22 the lifting thrust of the lid 5 which ? exerted by the elongation of the rod 12 of the actuator 11.

It can also be observed that starting from the geometric and functional configuration of the articulation group 14 which can be observed in figure 6, the angle ? that the connecting rod 18 and the crosspiece 22 form between them during the progressive opening of the lid 5 continues to decrease.

Experimental tests have allowed us to verify that as the amplitude of the angle decreases? the opening of the lid 5 is accelerated up to the continuously position up to the maximum opening position of figure 9.

So you get the advantage of higher speed? of opening of the lid 5 with respect to the prior art.

Finally, it can be observed that the rotation means 10 of the lid 5 which include the articulation group 14 and the actuator 11 which cooperate with each other, in the position in which they are arranged in figures 1 to 10 are capable of moving a lid 5 of any size and can therefore be applied to any evacuator of any size.

Eventually I can it may be necessary to vary the power of the drive unit 11a to adapt it to the weight of the lid 5 to be lifted.

The result is therefore obtained of standardizing the construction of the evacuators 1 by always using the same rotation means 10 of the lid 5 and only modifying the dimensions of the base 2 and of the lid 5 in response to the user's needs.

Clear economic advantages are therefore achieved which derive for the manufacturer from the smaller number of components to be managed in the warehouse and for the user greater availability? of spare parts for maintenance.

Obviously the evacuator 1 of the invention will be? electrically connected to buffer batteries from the mains and sar? managed by a special control unit including sensors for detecting smoke, heat or other non-standard conditions to command the opening of one or more? evacuators 1 of the invention in case of fire or other anomalous conditions.

As regards the cover 5, it will be able to be of any type and shape and can be made of any opaque, translucent or transparent material.

Furthermore, the evacuator 1 of the invention can also perform the functions of a skylight and be commanded to open and close as desired by the user for the ventilation of the rooms.

How long ? Having been written, it is understood that the evacuator 1 of the invention achieves all the intended purposes.

In the execution phase, modifications and variations not described may be made to the evacuator of the invention which, should they fall within the scope of the following claims, will all be considered protected by the present patent.

Claims (12)

1) Smoke and heat evacuator (1) comprising: - a base (2) delimited by a counterframe (3) and arranged peripherally to a through opening (4) made in the structure of a building, said through opening (4) being configured to connect the inside of one or more ? rooms of said building with the external environment; - a lid (5) delimited by a frame (6) associated with the counterframe (3) of said base (2) by means of hinges (7) which allow rotation of said lid (5) to open and close said through opening (4) ; - rotation means (10) of said lid (5) which comprise: - a linear electric actuator (11) comprising a motor drive unit (11a) which sets in linear motion a rod (12) slidably associated in a cylinder (13); - an articulation unit (14) operatively connected to said electric actuator (11) and comprising at least a first rod (15) which connects the head (16) of said rod (12) to said counterframe (3) and at least a second rod (17) which connects said cylinder (13) to said counterframe (3), characterized in that said articulation unit (14) also comprises at least one connecting rod (18) which connects said head (16) of said stem (12) to said frame (6). 2) Smoke and heat evacuator (1) according to claim 1, characterized in that said articulation unit (14) also comprises at least one third rod (21) which connects said first rod (15) and said second rod (17), in said third rod (21) are identified a first end? (21a) pivoted in an intermediate area of said first rod (15) and a second end? (21b) pivoted in an intermediate area of said second rod (17). 3) Smoke and heat evacuator according to any one of the preceding claims, characterized in that said connecting rod (18) comprises a first end? (18a) pivoted to said head (16) of said stem (12) and a second end? (18b) pivoted to a cross member (22) fixed between two opposite sides (6a, 6b) of said frame (6). 4) Smoke and heat evacuator (1) according to any one of the preceding claims, characterized in that said first rod (15) has the first end? (15a) pivoted to said head (16) of said stem (12) and said second rod (17) has the first end? (17a) pivoted to said cylinder (13), the second end? (15b) of said first rod (15) and the second end? (17b) of said second rod (17) are both connected to said counterframe (3) being both hinged to a support bracket (19) which belongs to a crosspiece (20) fixed between two opposite sides (3a, 3b) of said counterframe (3). 5) Smoke and heat evacuator (1) according to claim 4, characterized in that said second end? (15b) of said first rod (15) and said second end? (17b) of said second rigid rod (17) are pivoted in distinct points of said support bracket (19). 6) Smoke and heat evacuator (1) according to claim 5, characterized in that said second end? (17b) of said second rigid rod (17) ? arranged within the area delimited perimetrically by said base (5) and below the plane (X) defined by the upper surface (3c) of said counterframe (3) and said second extremity? (15b) of said first rigid rod (15) ? arranged above said plane (X) defined by said upper surface (3c) of said counterframe (3). 7) Smoke and heat evacuator (1) according to claim 6, characterized in that said second end? (15b) of said first rod (15) and said second end? (17b) of said second rod (17) are trained according to a direction (Z) inclined with respect to a vertical direction and incident to said plane (X) defined by said upper surface (3c) of said counterframe (3). 8) Smoke and heat evacuator (1) according to any one of the preceding claims, characterized in that it comprises hooking means (30) which are configured so as to block said frame (6) which delimits said cover (5) to said counterframe (3) which delimits said base (2) when said frame (6) ? arranged facing and close to said counterframe (3). 9) Smoke and heat evacuator (1) according to claim 8, characterized in that said hooking means (30) comprise: - a rod (31) associated with said cover (5) and having the ends? rotatably connected to support means (32) supported by said frame (6) of said cover (5); - one or more hooking bolts (33) fixed to said rod (31); - one or more coupling bolts (34) belonging to said counterframe (3) of said base (2) and configured to cooperate with said coupling bolts (33); - a tie rod (35) which connects said rod (31) to an operating lever (36) associated with said lid (5), said operating lever (36) being configured to operate said tie rod (35) and release said coupling bolts (33) from said coupling bolts (34) when the thrust produced by said head (16) of said rod (12) belongs said linear electric actuator (11) rotates said operating lever (36). 10) Smoke and heat evacuator (1) according to claim 9, characterized in that said tie rod (35) has the first end? (35a) fixed to a projecting hook (36) belonging to said rod (31) and the second end? (35b) fixed to said operating lever (36) by means of a fork (38) and a through pin (39). 11) Smoke and heat evacuator (1) according to claim 9 or 10, characterized in that said operating lever (36) ? rotatably associated with said lid (5) via a rotation pin (39a) and ? provided with an abutment surface (40) for contact with the head (16) of said stem (12) of said linear electric actuator (11). 12) Smoke and heat evacuator (1) according to any one of claims 9 to 11, characterized in that it comprises elastic means (41) associated with said rod (31) and configured to make the rotation of said rod (31) elastic ).