Abstract:
A control panel designed to be placed in a vertical plane, the control panel comprising the layered assembly of a flat base, of an elastomer sheet mounted against the base, the sheet being provided with openings and optionally with domes, and of a decorative fascia. The control panel is in addition provided with a means for protection against liquids made in one piece with the sheet, the protection means comprising elements projecting from the main surface of the sheet, the said elements being so arranged that when the control panel is in the substantially vertical plane and the liquid penetrates between the sheet and the decorative fascia, the liquid is guided along a determined course and re-emerges from the panel having avoided critical zones leading in particular to detectors.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit under 35 U.S.C. §371 of published PCT Patent Application Number PCT/EP 2012/053526, filed Mar. 1, 2012 and claims priority to French Patent Application 1152285 filed Mar. 21, 2011, and published as WO2012/126706 on Sep. 27, 2012, the entire contents of which is hereby incorporated by reference herein. 
     
    
     TECHNICAL FIELD OF INVENTION 
       [0002]    The invention relates to the liquid-proofing of a control panel suitable for use in motor vehicles and grouping together pushbuttons and knobs for the control of, for example, an audio system or of an air-conditioning system. 
       BACKGROUND OF INVENTION 
       [0003]    All vehicles and many other systems are today fitted with control panels that group together the interfaces necessary for the user to control functions as various as the audio system, the air-conditioning, the telephone, or navigation. 
         [0004]    In motor vehicles, these control panels are installed in the central console in a virtually vertical plane and are thus accessible to and manipulable by both the driver and the front-seat passenger. The controls are various and suited to the controlled function. In particular, pushbuttons, rotary knobs, and touch screens are provided. From a structural point of view, the control panels are a stack of distinct layers forming a unit. They are generally constructed from a base attached to a printed circuit covered with an elastomer sheet against which is placed a decorative fascia provided with the various interfaces. The printed circuit comprises electrical circuit-breakers switched (i.e.—opened and closed) by the actuation of the pushbuttons. After the fashion of computer keyboards, the elastomer sheet, often formed of silicone, protects the printed circuit from dusts and other external elements. It is in addition provided with deformable domes placed at the locations of the pushbuttons so that a dome applies a slight return force to a button opposed to the depression, the force causing the button to return to its initial position after having been depressed. In addition, the sheet is indented or provided with openings or other cut-outs that allow the passage of electroluminescent diodes as well as mechanical elements of a knob or of a button from the decorative fascia to the printed circuit. For reasons of modularity linked to the selection of vehicle options, the elastomer sheet can be formed of a plurality of partial sheets juxtaposed on the printed circuit. 
         [0005]    Water is one of the most undesirable external elements. Whether the cause of this is rain on a convertible, morning dew, the vigorous washing of the inside of the car, or the cause is an accidentally spilled drink, it is imperative that each control panel is provided with protections ensuring that the printed circuit is sheltered and does not risk being reached by a liquid. The elastomer sheet provides this liquid-proofing function in particular by means of a peripheral barrier slightly compressed against the inside face of the decorative fascia. However, due to the ageing and the differential expansion of the materials, the plurality of the sheets, the various shapes or the multiple cut-outs make this liquid-proofing function difficult to form reliably. Taking all these constraints into account it is important to propose an effective system for protection against liquids that can be adapted to various decorative fascia configurations. 
       SUMMARY OF THE INVENTION 
       [0006]    The present invention resolves the problem mentioned above by proposing the arrangement in accordance with claim  1  of a sheet that does not seek to necessarily prevent the entry of water into the control panel but provides for the evacuation of the liquid along safe paths thus protecting critical zones. 
         [0007]    The invention proposes a control panel, particularly for a motor vehicle, and intended to be placed substantially in a vertical plane, the panel comprising the layered assembly of a flat base, of an elastomer sheet, and of a decorative fascia. The flat base also comprises detectors that can, for example, be electrical contacts and circuit-breakers or optical forks. The base can in particular be a printed circuit. The elastomer sheet, which can be formed of silicone, is mounted against the base. The sheet is provided with openings. The decorative fascia has its inside face facing the main surface of the sheet. The decorative fascia is also provided with control buttons such as pushbuttons or rotary knobs. 
         [0008]    The base, the sheet, and the fascia are so arranged that the actuation of a control button is detected by a detector, for example detecting the switching of an electrical circuit-breaker. 
         [0009]    The control panel is advantageously provided with a means for protection against liquids. This means is preferably made in one piece with the elastomer sheet and comprises elements projecting from the main surface of the sheet. The elements are so arranged that when the control panel is in the substantially vertical plane and a liquid penetrates between the sheet and the inside face of the decorative fascia, the liquid is guided along a determined course and re-emerges from the panel having avoided the critical zones leading in particular to the detectors. 
         [0010]    The protection means comprises a plurality of linear elements with a slope relative to the vertical plane. Thus, in the vertical plane, the liquid flows from one element to the other, from the top of the panel toward the bottom of the panel, and emerges at an outlet situated at the bottom of the panel. 
         [0011]    Certain elements of the protection means project sufficiently from the main surface of the sheet for their tops to be in contact with the inside surface of the decorative fascia. They thus form liquid-tight barriers protecting the critical zones. 
         [0012]    Certain elements of the detection means project from the main surface of the sheet so that their tops are at a distance from the inside surface of the decorative fascia. They thus form guides that the liquid follows through capillarity to converge towards an outlet. 
         [0013]    Certain elements of the protection means are formed recessed into the thickness of the sheet itself. They thus form channels with a slope relative to the vertical plane such that the liquid follows by capillarity to converge towards an outlet. 
         [0014]    In addition, a zone of the main surface of the sheet can be perfectly smooth, of mirror polished type for example. This mirror zone encourages the flow of the liquid and prevents its stagnation. Thus, the mirror zone cooperates with the other elements of the protection means so as to evacuate or direct the liquid towards an outlet. 
         [0015]    Also, a zone of the main surface of the sheet can be grained. This zone slows the flow of the liquid and thus prevents drops from arriving too quickly at elements of the protection means and possibly passing over the elements in a cascade effect. The grained zone thus cooperates with the other elements of the protection means so as to controllably evacuate the liquid towards an outlet. 
         [0016]    In addition, the elastomer sheet can comprise a first partial sheet provided with a first part of the protection means and a second partial sheet provided with a second part of the protection means. The partial sheets are juxtaposed. The first and the second part of the protection means cooperate to evacuate the liquid penetrating the panel towards an outlet. The juxtaposed partial sheets join along a dividing line forming a slightly recessed channel relative to the main surfaces of the partial sheets. The channel has a slope relative to the vertical plane and cooperates with the elements of the protection means so as to evacuate or direct the liquid towards an outlet. 
         [0017]    The protection means can in addition comprise linear elements projecting from the inside face of the decorative fascia. These elements of the inside face cooperate with the elements of the sheet so as to evacuate or direct the liquid towards an outlet. 
         [0018]    The elastomer sheet can in addition be provided with deformable domes projecting from its main surface and so arranged that the actuation of a control button causes the elastic deformation of a dome thus generating a return force opposed to the actuation of the control button. After having been released, the button returns to its initial position. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0019]    An embodiment of the invention is now described by means of the following figures. 
           [0020]      FIG. 1  is an overall view of the inside of a convertible in which a control panel in accordance with the invention is integrated in the vertical part in the central console; 
           [0021]      FIG. 2  is a frontal view of the control panel of  FIG. 1  onto which a liquid is falling; 
           [0022]      FIG. 3  is an exploded view of the assembly of a printed circuit, of an elastomer sheet and of a decorative fascia that are the main components of the control panel of  FIGS. 1 and 2 ; 
           [0023]      FIG. 4  is a frontal view of the main surface of the elastomer sheet of the control panel of  FIGS. 1 to 3 ; 
           [0024]      FIG. 5  is a catalogue view showing different elements that can be used on a sheet to ensure the liquid-tightness of a control panel. These different elements are individually enlarged in  FIGS. 5A ,  5 B,  5 C,  5 D,  5 E,  5 F and  5 G, 
           [0025]      FIG. 6  is a view of the sheet of  FIG. 4  in which the route of the flow of liquid is indicated by arrows; and 
           [0026]      FIG. 7  is a plan view of a second elastomer sheet made in accordance with the invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0027]      FIG. 1  shows a control panel  10 , the object of the present invention, in a motor vehicle environment. Other environments, such as the train, the aircraft, the motorbike or any home automation apparatus having a control panel can also benefit from the advantages of the present invention. In  FIGS. 1 and 2  the control panel is shown installed between the front seats of a convertible, substantially in a vertical plane PZ of the central console, which plane contains the vertical axis Z. The decorative fascia  12 , the visible and accessible part of the control panel  10 , groups together the interfaces for control of the air-conditioning, of the audio system, or of navigation, for example. These functions are mainly controlled by means of pushbuttons  14  and rotary knobs  16 . Other control means, such as touch screens or toggle switches are contemplated. The natural vertical orientation from bottom to top, along the axis Z indicated in the figures will be used in this description. 
         [0028]      FIG. 2  shows an example of a decorative fascia  12  provided with pushbuttons  14  and with three rotary knobs  16 . As shown diagrammatically by the drops of water  20  above the control panel  10 , the panel can be subject to bad weather, or even to any form of projection of liquid  20 . 
         [0029]      FIG. 3  presents certain components of the control panel  10  in an exploded view. A printed circuit (PCB)  22  is covered with an elastomer sheet  24 , generally of silicone, on which is placed the decorative fascia  12 . 
         [0030]    The printed circuit  22  is provided with detectors that can be electrical circuit-breakers or optical forks. It is also provided with electronic components as well as the set of tracks providing their electrical interconnection and with electroluminescent diodes (LED) used for the back-lighting of certain parts of the fascia  12 . 
         [0031]    The decorative fascia  12  is the visible component of the panel  10 . It includes an inside face  26  facing the elastomer sheet  24  and an outside face from which emerge the manipulable pushbuttons  14  and rotary knobs  16  actuation of which switches the circuit-breakers of the printed circuit  22 . 
         [0032]    The elastomer sheet  24  placed between the printed circuit  22  and the inside face  26  of the decorative fascia  12  covers the printed circuit  22 . It is provided with openings necessary for the passage of spindles and other mechanical parts forming in particular rotary knobs  16  or other detectors such as optical forks. The sheet  24  is also provided with openings at the locations of the LED or other light sources used for the back-lighting of screens as well as with elastically deformable domes  30  placed at the locations of the circuit-breakers and of the pushbuttons  14 . Under each dome, a chip of electrically conductive material ensures the switching of the circuit breaker on depression of a dome. Due to the elasticity of the domes a button  14  returns by itself and automatically to its original position, after having been pushed. 
         [0033]    When the panel  10  is assembled, the inside face  26  of the decorative fascia  12  is at an interface distance from the main face  32  of the sheet  24 . 
         [0034]      FIG. 4  shows in detail the elastomer sheet  24  made in accordance with the invention. The sheet  24  is presented from the view of its main face  32  that is facing the inside face  26  of the decorative fascia  12 . The sheet  24  is approximately rectangular. In the lower half of the sheet  24  are seen three horizontally aligned circular openings  36 . They correspond to the passages of three rotary knobs  16  that can in particular allow regulation of the air-conditioning: direction, force, and temperature of the air-flow. In addition a square opening  38  and another circular one  40  of smaller sizes than the three preceding ones are respectively formed at the center and at the top left of the sheet  24 . Lastly, none of the four upper, lower, right, and left edges is perfectly rectilinear and each presents cut-outs and notches. In particular, two lateral rectangular cut-outs  42  are formed symmetrically in the right edge and in the left edge and a lower cut-out  44  that is also rectangular and is formed at the center of the lower edge. 
         [0035]    In the example of sheet  24  of  FIG. 4 , the circular openings  36 , the lateral cut-outs  42 , the lower cut-out  44  and the small central cut-out  38  are examples of critical zones that must imperatively be protected from the entry of liquid  20 . In  FIG. 4 , these zones are surrounded by a peripheral broken line. The sheet  24  is of substantially uniform thickness and the domes  30  extend from the main surface  32  towards the decorative fascia  12 . 
         [0036]    The sheet  24  shown in the figures and briefly described above is only a non-limiting example of the support of the invention. Sheets  24  can be of any shape, they can be larger or smaller, they can be provided with a different number of openings and indentations of any shape. They can be symmetrical like the example of the figures or non-symmetrical. 
         [0037]    The sheet  24  is provided with a means  50  for protection against liquids  20 . The means  50  comprises barriers  52 , ribs  54 , and channels  56  that cooperate with each other, in the manner similar to a funnel, to conduct or direct the least droplet from its entry at any point on the upper edge  60  towards a lower outlet  62 . The liquid  20  is diverted progressively with its descent so as to avoid the critical zones  36 ,  38 ,  42 ,  44 . 
         [0038]    The barriers  52  and the ribs  54  are linear elements projecting relative to the main surface  32  of the sheet  24  while the channels  56  are linear elements recessed relative to the main surface  32  of the sheet  24 . Observed individually in the vertical plane PZ, in accordance with  FIG. 4 , and more particularly in the enlarged zone, these guiding elements have a slope p along which the liquid  20  naturally flows. 
         [0039]      FIG. 5  and the associated  FIGS. 5A ,  5 B,  5 C,  5 D,  5 E,  5 F, and  5 G show, from a second sheet  24 , a non-limiting catalogue of different elements of the means  50  for protection against liquids  20 . The liquid  20  can be guided by means of barriers  52  ( FIG. 5C ) known as compression barriers. These barriers  52  rise relative to the main surface  32  of the sheet  24  by a height h greater than the interface distance and thus have their tops in contact and slightly compressed against the inside face  26  of the decorative fascia  12  when the panel  10  is assembled. The ribs  54  ( FIG. 5B ,  5 D,  5 E) are less high than the barriers  52  and do not contact the inside face  26  of the decorative fascia  12 . They can in particular be of triangular ( FIG. 5B ), rectangular ( FIG. 5E ), or rounded ( FIG. 5D ) section as required and depending on the configuration of the panel  10 .  FIG. 5  also shows the channels  56  ( FIG. 5A ) formed recessed into the thickness of the sheet  24  itself and having half-round sections, although other sections, square or triangular, are possible. A rib  56  can in addition be associated with a channel  54  so as to form a double protection ( FIG. 5F ). Lastly, in order to very locally protect a location, such as a corridor for an LED, a small rib  58  ( FIG. 5G ) in the form of a roof with two sides is placed over the location to be protected. 
         [0040]    Associated with the barriers  52 , with the ribs  54 ,  58 , and with the channels  56 , the flow of the liquid  20  towards an outlet  62  can be orientated and encouraged by particular surface states in certain zones of the sheet  24 . Thus, in  FIG. 5  and only by way of illustration, are shown two zones  64  the surfaces of which are perfectly smooth, of mirror polished type, and two zones  66  the surfaces of which are grained. The flow is facilitated in the mirror zones  64  and thus the stagnation of the liquid  20  is prevented. In the grained zones  66 , the flow is on the contrary slowed which permits the avoidance of large drops  20  arriving too quickly at the ribs  54 ,  58 , or the channels  56  and passing over which would cause a cascade effect incompatible with the precise guiding of the flow. 
         [0041]    The sheet of  FIG. 4  is rectangular and symmetrically divided into six zones themselves virtually rectangular. Three upper zones: left HG, central HC and right HD, are situated just above three lower zones: left BG, central BC and right BD. The dividing lines between these zones are formed by compression barriers  52  extending in a straight line. In addition vertical barriers  52  extending from side to side of the central zone BC define two outlet corridors  68 . The upper zones HG, HC, HD all have a slight opening in the barrier  52  forming their lower dividing line and, at this position, each barrier  52  adopts a slight slope p so as to create a funnel discharging into the outlet corridors  68 . Similarly, the barrier  52  situated between the upper HC and lower BC central zones is in the form of a chevron and guides the liquid  20  from the upper central zone HC towards the outlet corridors  68 . The sheet  24  being thus partitioned, a liquid  20  that has entered one of the three upper zones HG, HC, HD, leaves naturally through the outlet corridors  68 . The critical zones  36 ,  38 ,  42 ,  44 , identified above, are protected. In addition barriers  52 , ribs  54 , and channels  56  are placed in the three upper zones HG, HC, HD. Each of these elements has a slope p that orientates the liquid  20  from its entry towards the outlet corridors  68 . Due to these additional elements the liquid  20  does not accumulate at the bottom of the upper zones HG, HC, HD, but quickly converges towards an outlet  62 . 
         [0042]      FIG. 6  indicates with arrows F various flow paths taken by a liquid  20  having entered at the top of the panel  10  and having been led by the barriers  52 , the ribs  54 ,  58  and the channels  56  towards the outlet  62  situated below. 
         [0043]    In an alternative construction and in order to satisfy the numerous requirements of different options with which vehicles may be provided, the sheet  24  can be formed by juxtaposition of a plurality of partial sheets. For example, partial sheets can be prepared to accord with different air-conditioning control systems and other partial sheets formed to accord with different audio systems. The partial sheets corresponding to the customer&#39;s choice will then be selected and juxtaposed at assembly. 
         [0044]    Thus, in  FIG. 4  the lower zones BG, BC, BD can form part of a first partial sheet  24   a,  while the three upper zones HG, HC, HD can form three other distinct partial sheets  24   b,    24   c,    24   d.  Each partial sheet  24   a - 24   d  is provided with a part  50   a - 50   d  of the protection means  50 . The four partial sheets  24   a - 24   d  are then juxtaposed contiguously to cover the printed circuit  22  and thus the parts  50   a - 50   d  of the protection means  50  are completed to together evacuate the liquid  20 . The dividing line between two partial sheets  24   a,    24   b  forms a channel  56  with a slope p and is one of the elements of the protection means  50 . 
         [0045]    Another sheet  24  made in accordance with a similar principle to the first sheet is shown in  FIG. 7 . The barriers  52 , the ribs  54  and the channels  56  of this other sheet, also rectangular, form a left funnel  70 , a central passage  72  and a right funnel  74 . The left funnel  70  in its upper part comprises two banks of ribs  54 , each bank forming a breakwater. Under the ribs  54 , four domes  30  are placed in a rectangle at the center of which a rectangular critical zone intended for the passage of an LED is protected by a rib  58  forming a roof with two sides. The upper part of this left funnel  70  leads to an outlet corridor  68  that is also rectilinear and provided with ribs  54  guiding the liquid towards the corridor center  68 . 
         [0046]    The right funnel  74  comprises an upper part, of smaller dimensions than those of the left funnel  70 , and a rectilinear outlet corridor  68  having no ribs. At the center of its upper part, this straight funnel  74  comprises another LED passage also protected by a rib  58  forming a roof with two sides. 
         [0047]    Between the left  70  and right  74  funnels is a central passage  72  in which two new LED passages are also each protected by a rib  58  forming a roof with two sides. The central passage  72  is also defined in its lower part by a barrier  52  with a double slope leading towards the right outlet duct  68  via an opening formed in one of the barriers  52  defining this outlet duct  68 . 
         [0048]    In the preferred embodiment described above, the elastomer sheet  24  is molded and the means  50  for protection against liquids is integrated in it. In complementary manner, ribs can be provided projecting from the inside face  26  formed in one piece with the decorative fascia  12 . On assembly of the control panel  10 , ribs  54  of the sheet  24  enter into contact and then cooperate with ribs of the inside face  26 , thus together forming liquid-tight barriers impassable by a liquid  20 .