Patent Publication Number: US-2013228730-A1

Title: Safety Wall

Description:
The present invention relates to a safety wall intended to be positioned in front of at least one obstacle to absorb a collision impact with said obstacle at least in part, the said safety wall comprising a first element having an intake arranged to be connected to a source of pressurised air, the said first element being arranged so that it can be inflated with air to a first predetermined pressure and having a collision zone, the said first element also being connected to a second element arranged so that it can be inflated with air to a second predetermined pressure. 
     Said safety wall is known for example from document FR2930452 describing an envelope comprising at least one inflatable element. The safety wall described in this document is intended to delimit sports or playground areas. Several envelopes comprising at last one inflatable element can be placed side by side to form a safety wall of greater or lesser length, the different envelopes being attached by means of hook and loop fastening strips for example or a zip fastening system. 
     Document FR2928667 discloses a deformable safety barrier comprising a flexible structure having at least one housing in which an inflatable bag is inserted. This safety barrier is intended to be placed between a roadway and a vertical support to soften the impact when a vehicle accidentally comes off the roadway. With said safety barrier, the absorbing of the impact is dependent on the set, predetermined pressure at which the inflatable bags are inflated, a pressure that is too high not being indicated since it would harden the safety barrier and would lead to a  trampoline  effect in the event of impact, and a pressure that is too low would insufficiently absorb the impact. 
     Unfortunately, said safety walls are composed of elements inflated to a set, predetermined pressure once the safety wall is in place. If a vehicle collides with said safety walls, the absorption of the impact therefore depends on the predetermined pressure within the inflatable elements, irrespective of the magnitude of the collision force. Said safety walls are therefore not adapted for absorbing all impacts, this absorption being limited by the set, predetermined pressure of the inflatable elements. 
     It is the objective of the invention to overcome the disadvantages of the prior art by providing an inflatable safety wall which allows specific absorption of impacts, the pressure within the inflatable elements varying in accordance with the magnitude of the collision force applied to the safety wall. 
     Therefore, to solve these problems, provision is made according to the invention for a safety wall such as first indicated above characterized in that the said first element communicates with the said second element via at least one decompression valve allowing transfer of the air contained in the said first element towards the said second element over and above a predetermined pressure threshold in the said first element, the said second element further having at least one evacuation valve to evacuate the air externally, the valve being arranged to allow transfer of the air contained in the said second element towards a surrounding medium over and above a predetermined pressure threshold in the said second element. 
     Said safety wall allows the specific absorption of impacts according to the magnitude of the collision force since the pressure within the said inflatable elements is able to vary, the pressurised air in the said first inflatable element having a collision zone being capable of passing over to the second inflatable element above a predetermined pressure threshold in the said first inflatable element via at least one decompression valve, the said second element also having at least one evacuation valve evacuating air externally and arranged to allow transfer of the air contained in the said second element towards a surrounding medium when the pressure in the said second element exceeds a predetermined threshold. 
     Said safety wall therefore allows the initial pressure of the inflatable elements to vary in accordance with the collision force applied to the safety wall. Advantageously, this variation in pressure allows optimal absorption of the impact caused by a collision, the pressure of the inflatable elements adapting to the magnitude of the collision force. Therefore, the disadvantages encountered with inflatable safety walls described in the prior art such as the  trampoline  effect (pressure in the inflatable elements that is too high) are overcome with the present invention. 
     According to one embodiment of the safety wall of the invention, the said safety wall further comprises a third element connected to the said second element, the said second and third elements communicating together via at least one decompression valve allowing transfer of the air contained in said third element towards the said second element over and above a predetermined pressure threshold in the said third element. The presence of a third inflatable element reinforces the efficacy of the said safety wall, this third element contributing towards specific absorption of the collision force. Subsequent to a first partial absorption of the said collision force by the said first and second elements, the said third element is effectively able to further absorb part of the residual shockwave. 
     According to another embodiment of the safety wall according to the invention, the said third element is divided longitudinally into a first and a second compartment. 
     According to another embodiment of the safety wall according to the invention, the said first element is divided longitudinally into a first and a second compartment. 
     According to another embodiment of the safety wall of the invention, the said second element is divided longitudinally into a first and a second compartment. 
     The dividing of the different elements forming the said safety wall allows the collision force to be distributed across a plurality of compartments, which contributes towards optimal distribution of the said collision force which is hence better absorbed. 
     Advantageously, the said first and second compartments communicate together via at least one decompression valve. This communication between the said first and second compartments formed from an inflatable element of the said safety wall ensures optimal absorption of the said collision force, the pressurised air in the said first compartment being able to pass over to the said second compartment when the pressure in the said first compartment exceeds a predetermined threshold. 
     Preferably, the said safety wall of the invention comprises several air intakes each connected to a component (inflatable element or compartment formed from an inflatable element) of the said safety wall. The different components of the said safety wall are pressurised at an initial pressure which is to be permanently maintained before a collision force is applied against the said safety wall. For this purpose, several pressurised air intakes are provided, and each is connected to a component of the said safety wall, the pressurised air fed to these different components being supplied by one or more compressors. 
     Preferably, the said safety wall of the invention comprises fixing elements to hold the safety wall in place. The said safety wall indeed needs to be maintained in position in front of the obstacle so that the said safety wall does not move under the effect of the said collision force and is able absorb the said collision force with efficacy. 
     Preferably, the said fixing elements are securing straps and/or rings through which ring bolts are passed. 
     Advantageously, the said collision zone comprises rigidifying strips. Said rigidifying strips allow the safety wall to be held in an adequate position to ensure optimal absorption of the said collision force. These rigidifying strips may also contribute towards optimal distribution of the said collision force over the entire said collision zone of said safety wall. 
     Preferably, at least one of said elements of the said safety wall is surmounted by an advertising banner. 
     Advantageously, the said safety wall of the invention is formed by a succession of safety walls placed side by side or superimposed. 
     Other forms of the safety wall according to the invention are indicated in the appended claims. 
     The invention also concerns the use of a safety wall to absorb a collision impact. 
     Other forms of use of a safety wall according to the invention are indicated in the appended claims. 
    
    
     
       Other characteristics, details and advantages of the invention will become apparent from the description given below given as a non-limiting illustration and with reference to the appended drawings. 
         FIG. 1  is an illustration of one embodiment of the safety wall according to the invention. 
         FIG. 2  is another illustration of one embodiment of the safety wall according to the invention. 
         FIG. 3  is an illustration of a safety wall according to the invention showing the rigidifying and fixing elements of the said safety wall. 
     
    
    
     In the Figures, same or similar elements carry the same references. 
       FIG. 1  illustrates a safety wall according to one embodiment of the invention comprising a first inflatable element ( 1 ) and a second inflatable element ( 2 ) both fed with compressed air via intakes ( 3 ) arranged so that they can be connected to a compressor (not illustrated). The first ( 1 ) and second ( 2 ) inflatable elements communicate together via a decompression valve ( 5 ) arranged to allow the passing of the air contained in the said first element ( 1 ) towards the said second element ( 2 ) solely when the air pressure inside said first element ( 1 ) is higher than a threshold value. The said second element also comprises an evacuation valve ( 6 ) evacuating air externally and arranged to allow the output of air from the said second element ( 2 ) towards the outside medium solely when the air pressure inside said second element ( 2 ) is higher than a threshold value. Therefore, when a collision force (F) is applied against the said safety wall on said collision zone ( 4 ) and when the threshold air pressure value is exceeded in said first element ( 1 ), the said decompression valve ( 5 ) opens under the effect of the pressure and allows the passing of air from said first element ( 1 ) towards said second element ( 2 ) whose external evacuation valve ( 6 ) opens when the air pressure inside the said second element ( 2 ) exceeds a threshold value. The collision force (F) is therefore first partly absorbed in the said first element ( 1 ) then in said second element ( 2 ) into which the air initially contained in said first element ( 1 ) has passed, subsequent to application of the said collision force (F) on said collision zone ( 4 ). The external evacuation valve ( 6 ) prevents the pressure inside said second element ( 2 ) from exceeding a threshold value defining the opening of said external evacuation valve ( 6 ). 
       FIG. 2  illustrates a safety wall according to another embodiment of the invention comprising the same elements as those described in  FIG. 1  but further comprising a third inflatable element ( 7 ) fed with compressed air via an intake ( 3 ) arranged so that it can be connected to a compressor (not illustrated), the said third element communicating with the said second element ( 2 ) via a decompression valve ( 8 ) arranged to allow passing of the air contained in the said third element ( 7 ) towards the said second element ( 2 ) solely when the air pressure inside said third element ( 7 ) is higher than a threshold value. Therefore, when a collision force (F) is applied against the said safety wall on said collision zone ( 4 ) and when the threshold air pressure value in the said first element ( 1 ) is exceeded, the said decompression valve ( 5 ) opens under the effect of the pressure and allows the air contained in said first element ( 1 ) to pass into the said second element ( 2 ) whose external evacuation valve ( 6 ) opens when the air pressure inside the said second element ( 2 ) exceeds a threshold value. The collision force (F) is therefore first partly absorbed in said first element ( 1 ) then in said second element ( 2 ) and finally in said third element ( 7 ). The external evacuation valve ( 6 ) prevents the pressure inside the said second element ( 2 ) from exceeding a threshold value defining the opening of the said external evacuation valve ( 6 ). 
       FIG. 3  illustrates a safety wall according to the invention comprising a first inflatable element ( 1 ), a second inflatable element ( 2 ) and a third inflatable element ( 7 ). The first inflatable element ( 1 ), on the collision zone ( 4 ), has rigidifying strips ( 9 ) ensuring the maintaining in position of the safety wall, the said safety wall also be fixed to the ground via attaching elements ( 10 ) themselves fixed to the ground via a ring-bolt ( 11 ). 
     Evidently the present invention is in no way limited to the above-described embodiments and numerous modifications can be made thereto without departing from the scope of the appended claims.