Patent Publication Number: US-2010107292-A1

Title: Headset Including a System for Securing the Visor by Microfibres

Description:
PRIORITY CLAIM 
     This application claims priority to French Patent Application Number 08 05768, entitled Headset Including a System for Securing the Visor by Microfibres, filed on Oct. 17, 2008. 
     FIELD OF THE INVENTION 
     The field of the invention relates to headsets comprising at least one supporting shell and a visor. 
     BACKGROUND OF THE INVENTION 
     A headset for aircraft pilots, notably of fighter aeroplanes, is generally multifunction and is equipped with visors. Such a headset comprises a rigid supporting shell which generally surrounds the top, the back and the side portions of the wearer&#39;s skull. The headset generally includes visors through which the wearer of the headset can see his environment; these visors are more often than not retractable towards the top of the skull and provide protection for the face against various attacks (wind, dust, light or violent lighting, etc.). For night flights, a night vision system can also be inserted in front of the eyes of the wearer. 
     The problem that arises for visored headsets is securing the visor in any position. In practice, because of their weight and the severe usage stresses on board military aircraft, particularly the vibrations and temperature variations, the visors are difficult to secure. The distance between the centre of gravity of the visor and its centre of gravity is also a cause that can tend to cause the visor to drop. 
     The solutions that currently exist as represented by  FIG. 1  are securing systems based on the friction of metal or plastic parts  12  associated with a torque generally positioned level with the hinges of the visor. This system is difficult to adjust and varies with temperature. It also has the drawback of sliding under vibration. 
     Another securing system involves providing notches  11 , plastic clips or ball springs, but imposes defined positions. This system is also fairly hard to manoeuvre, so it may hamper the pilot in his mission. 
     SUMMARY OF THE INVENTION 
     The aim of the invention is to propose a system for securing the visor, and more generally any removable element positioned on the supporting shell, making it possible to improve the resistance in piloting operation. 
     More specifically, the invention is a headset comprising at least a supporting shell and a moving visor that can be displaced between two extreme positions, characterized in that it includes a system for securing the visor in any position between the two extreme positions by friction between the visor and the supporting shell, the friction being provided by at least one microfibre felt element. 
     The microfibre felt elements have a surface area that is big enough to produce a friction force between the supporting shell and the headset visor making it possible to secure the visor in any position. The friction resistance is sufficient for the visor to be secured in its position regardless of the severe military flight operation conditions. 
     Depending on the positions on the headset where the pilot wants the visor to be best secured, the headset advantageously includes one or more microfibre felt elements. The microfibre felt elements can be present on the supporting shell on the outside of the headset and/or on the visor on the inside. 
     The use of friction surface by microfibre felt makes it possible advantageously to produce a continuous friction force between the supporting shell and the visor over the entire displacement of the visor. The pilot can thus secure the visor in any position by an immediate manipulation. 
     The use of microfibre felt also makes it possible to locate the friction force on the centre of gravity of the visor, generally corresponding to the upright of the visor. The friction force needed to secure the visor in its position then becomes weaker and makes it possible to secure the visor more effectively. This makes it possible to avoid the noises caused by mechanisms that have too much vibration play. 
     Advantageously, the securing system comprises at least two microfibre felt elements, a first element fixed to the supporting headset and a second element fixed to the visor. 
     Advantageously, when the two felt elements are in friction, the orientation of the microfibres of the first felt element is not parallel to the orientation of the microfibres of the second felt element. 
     Thus, in one embodiment, the microfibres of the felt elements are oriented so that the friction force is greater in a first direction of displacement of the visor than in a second direction of displacement of said visor. 
     Advantageously, the kinematics of the visor on the headset are variable to vary the friction force on displacement of the visor from one extreme position to another extreme position. This way, it is possible to design the securing system for the visor to be very strongly secured in the usual positions of the visor, that is, when it is lowered into the working position and when it is raised into the position of non-use. Generally, the intermediate positions between these two positions are not used and the microfibre system makes it possible to provide little friction force opposition in this area of displacement of the visor. 
     Or, in another embodiment, the microfibre felt has a variable surface area to vary the friction force on displacement of the visor from one extreme position to another extreme position. For example, in a first securing position, the microfibre felt element or elements are such that the friction surface area is great. And for the positions in which the visor is displaced and generally not very secured, the friction surface area is small. 
     Advantageously, the headset comprises at least one microfibre felt element fixed only to the visor or, in another embodiment, it comprises at least one microfibre felt element fixed only to the supporting headset. 
     The invention relates also to headsets designed with no specific visor and comprising a microfibre felt element making it possible to produce a friction resistance with a standard moving visor. 
     The invention also relates to visors that include a microfibre felt element making it possible to produce a friction resistance with a standard headset. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be better understood and other benefits will become apparent from reading the following description, given by way of nonlimiting example, and from the appended figures in which: 
         FIG. 1  represents an aircraft pilot&#39;s headset as described in the prior art. 
         FIG. 2  partly represents the headset comprising the rigid shell and the visor on which a microfibre felt is glued. 
         FIG. 3  represents, in the top drawing, a partial diagram of the headset and the forces that interact on a movement of the visor of the headset for a securing system level with the rotation axis of the visor and a securing system on the visor using a microfibre felt. In the bottom drawing, the headset shows the visor positioned in the two extreme positions. 
         FIG. 4  represents the headset with a microfibre felt on the upright of the visor. 
         FIG. 5  shows the headset with two facing microfibre felt elements. 
         FIGS. 6   a  and  6   b  represent a headset with microfibre elements having various forms. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENT 
     The invention is intended particularly for aircraft pilot headsets. The existing solutions, as described in  FIG. 1 , propose visor securing systems  13  based on mechanical means  11  and  12  that are difficult to manipulate, imprecise and not very effective in securing the visor when there are vibrations and changes of temperature. 
     The visored headsets for aircraft pilots generally comprise a rigid supporting headset and a moving visor that can perform a rotary movement about an axis positioned in the middle of the headset. 
     The invention is innovative in light of the existing solutions in that it proposes a solution for securing the visor  3  by microfibre felt elements  4 .  FIG. 2  shows an application mode in which the microfibre felt  4  is fixed to the visor  3 . Preferably, the microfibre felt is glued to the central part of the visor in order for the friction force to be located level with the centre of gravity of the visor. In this way, the friction force does not need to be high. 
     In the existing systems, the securing system generally provides the braking for the visor on the rotation axes of the visor. Given the difference between the centre of gravity of the visor and the braking means, the force needed to secure the visor is great. With the slightest difference in grip, a loss of force can occur and result in play on the visor and consequently a gradual lowering if said visor is in the raised position. This is why, in conditions of vibration or strong temperature changes, these securing systems soon fail. 
       FIG. 3  illustrates the forces interacting for a securing system  23  according to the prior art positioned level with the rotation axis of the visor and for a system of securing by microfibre felt  31  fixed to the visor  3 . The force exerted by the weight of the visor is represented by the arrow P. For the securing system  23 , the torque needed to secure the visor  3  is equal to the distance  22  multiplied by the force f 1 . For the securing system with microfibre felt  31 , the necessary torque is equal to the distance  21  multiplied by the force f 2 . Since the length  21  is greater than the length  22 , the force f 2  provoked by the microfibre felt is weak compared to the force f 1  to exert one and the same visor securing torque. In the case of the securing system  23 , the torque is identical regardless of the position of the visor. 
     The benefit of using microfibre felt elements is that it makes it possible to add securing points at variable positions and preferably for positions in which the visor is generally secured. A headset visor performs a rotary displacement between two extreme positions  6  and  7  and is described in the bottom drawing of  FIG. 3 . A pilot generally seeks to secure his visor in the lowered position  6  or in the raised position  7 . To achieve this aim, the felt elements are positioned so that the friction force is greatest in these two positions. 
     A microfibre felt consists of an adherent face, preferably glue, and a face comprising the microfibres producing the friction. The intensity of the friction force depends on the density, the rigidity and the length of the microfibres. The surface area of the felt element is also used to adjust the friction force. The friction force can also be adjusted by designing the kinematics of the visor so that it is more or less in friction with the felt elements depending on the positions of the visor. 
     It is possible to implement different solutions to produce a friction force between the supporting shell and the visor. In practice, it is possible to fix the microfibre felt only to the headset, only to the visor or to both at a time, facing. 
       FIG. 4  represents a partial diagram of the headset. In this solution, the felt  41  is fixed to the upright of the visor  3  at the top central level on the face oriented towards the rigid shell  2  of the headset. Thus, the microfibres of the felt  41  exert a friction force on the shell  2  of the headset when the visor is in motion between the two extreme displacement positions. In this simple friction configuration, regardless of the position of the visor  3  relative to the rigid shell, the friction force is the same. The felt is positioned on the top upright of the visor in order for it also to be in contact when the visor is in the bottom position  6 . 
       FIG. 5  represents a partial diagram of the headset comprising two microfibre felt elements, one  42  positioned on the shell of the headset  2  and the other  41  positioned on the visor. Obviously, the microfibre felt elements of the shell of the headset are positioned on the outer face of the shell. This way of implementing the securing of the visor produces a double friction when the felts are facing one another. The interaction of the microfibres  41  and  42  exerts a better securing force than simple friction on a smooth surface. For the friction force to be constant regardless of the position of the visor, it is necessary for the entire surface of the shell of the headset between the extreme positions of the visor to be covered with microfibre. Preferably, this surface, on displacements  44  and  43  of the visor, has a width identical to the width of the microfibre felt  41  fixed to the visor. 
     The securing system is not limited to two microfibre elements. If the wearer of the headset does not require a strong securing force only in particular positions of the visor, a number of microfibre elements are fixed to the shell of the headset  2 . For example, if the wearer wants only a strong securing in the bottom position  6 , to avoid vibration of the visor  3 , and a strong securing in the raised position  7 , to avoid vibrations and the lowering of the visor, the securing system is designed so as to include a first microfibre felt element at the top level of the shell of the headset, to secure the visor in the top position, a second element on the front of the headset, to secure the visor in the bottom position, and a third element on the upright of the visor. Preferably, for a securing system with felts positioned facing one another, the microfibres are of short length, commonly called short-pile velvet. 
     In this type of configuration, the direction of the microfibres relative to the friction surface can be different depending on the felt elements, notably between the felt elements positioned on the visor and those positioned on the shell of the headset. For example, the fibres have a direction that is not perpendicular relative to the friction surface for the felt elements positioned on the headset. This arrangement makes it possible to have a weak friction in one direction of displacement of the visor and a strong friction in the opposite direction. This possibility is particularly useful to favour the raising of the visor and exert a strong securing force in the lowering movement of the visor. 
     To vary the friction force between the visor  3  and the shell  2 , one solution is to vary the friction surface area on the displacement of the visor.  FIGS. 6   a  and  6   b  represent, by way of nonlimiting example, two exemplary felt forms.  FIG. 6   a  shows a felt element  43  of trapezoidal form and  FIG. 6   b  represents a felt element  45  with a wide rounded end and a less wide rectangular end, the felt having a form resembling a vertical section of a light bulb. In these two modes, the felt element  41  fixed to the visor  3  has an identical form. Preferably, the friction surface is wider on the top level of the shell in order to cancel out the force exerted by the weight of the visor. 
     The securing system comprising microfibre felt meets the objectives sought. In practice, the friction force exerted between the supporting headset and the visor can be modulated according to the area of application and according to the wearer of the headset. This securing system also makes it possible to exert a continuous and constant force allowing the wearer of the headset the possibility of securing the visor in any position. Depending on the type of microfibre felt used and depending on the orientation of the microfibres, the friction force can also be modulated allowing for a passing direction and a strongly braked direction for the visor. This securing system is also lighter and less obvious than the securing systems offered in the prior art. For the aeronautical field, in which the headsets incorporate numerous electronic elements, this type of securing is very advantageous. 
     The invention can also be applied to headsets that include a plurality of visors, notably those that include a tinted visor to protect from the sun and a clear visor for projecting information. The invention applies to visored headsets generally and relates to the field of aeronautics and the field of automobiles or any other field for which an individual requires protection of the skull.