Abstract:
A contactor carriage fitted so as to move translationally in an electrical switch of a motor vehicle, in a unit providing controls under the steering wheel, in order to establish according to a user command, an electrical contact for one or more predefined positions of the path of the carriage is disclosed. The carriage has at least one electrical contacting emplacement, a first housing for accommodating a high-current contactor element and a second housing for accommodating a low-current contactor element. An electrical contact is established at said emplacement either by placing a high-current contactor element in the associated housing or by placing a low-current contactor element in said housing.

Description:
FIELD OF THE INVENTION 
     The present invention relates to the field of electric switches for motor vehicles and in particular of switches of a control assembly beneath the steering wheel of a motor vehicle. 
     BACKGROUND ART 
     Many electric switch structures have already been proposed. In particular, electric switches are known with a contactor carriage mounted so as to be able to move in translation in order to establish, according to a command of a user, an electric contact for one or more predefined positions of the path of the carriage. 
     These weak-current or strong-current contactor carriages make it possible to establish the electric contact, notably by friction contact facing sets of conductive electric tracks in order to modify switching states. 
     A “weak current” is a current designed to broadcast, collect or exchange information in the form of electric signals. The currents in question are sometimes very weak (a few mA to a few μA). 
     In contrast, a “strong current” is a current capable of providing electric energy notably designed for functions of lighting, heating and driving force (lamps, resistors, motors, etc.). The currents in question are of the order of a few hundred mA to several A. 
     It is understood that the performance required, notably in mechanical and electrical resistance, of weak-current or strong-current contactor carriages is not at all the same. Notably, strong-current contactors must withstand possible electric arcs which may be formed and which may damage the electric contact. 
     However, in the motor vehicle field, certain vehicle options are chosen by the customer at the last moment of assembly of the vehicle. 
     It is then necessary that the switches of the control assembly, and in particular of the controls under the steering wheel, possess a great deal of modularity and can therefore be easily inverted depending on the wishes of the customer. 
     SUMMARY OF THE INVENTION 
     The object of the present invention is therefore to propose an electric switching device of a motor vehicle having a greater degree of modularity. 
     Accordingly, the subject of the invention is a contactor carriage designed to be mounted so as to move in translation in an electric switch of a motor vehicle, preferably in an assembly of controls beneath the steering wheel, in order to establish, according to a command of a user, an electric contact for one or more predefined positions of the path of said carriage, comprising at least one location of electric contact, characterized in that it comprises a first housing designed to receive a strong-current contactor element, and a second housing designed to receive a weak-current contactor element, so that an electric contact is capable of being established at said location either by the installation of a strong-current contactor element, or by the installation of a weak-current contactor element in the associated housing. 
     A further subject of the invention is an electric switch of an assembly of controls beneath the steering wheel of a motor vehicle, characterized in that it comprises a contactor carriage as defined above, and in that it also comprises at least one weak-current or strong-current contactor element in order to establish, according to a command of a user, an electric contact at one or more given positions on the path of said carriage. 
     A further subject of the invention is an elastic weak-current contact strip designed to be installed in a housing of a contactor carriage as defined above, in order to establish, according to a command of a user, an electric contact for one or more predefined positions of the path of said carriage, comprising at least one location of electric contact, so that an electric contact is capable of being established at said location, characterized in that it has the shape of a fork having at least two branches capable of establishing two simultaneous electric contacts and in that each branch has a curved end. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other advantages and features will appear on reading the description of the invention and the appended drawings in which: 
         FIG. 1  is a bottom view of the electric switch according to the invention on a circuit track, 
         FIG. 2  is a schematic side view of the electric switch of  FIG. 1 , 
         FIGS. 3 ,  4 ,  5  and  6  are bottom views in perspective of variant embodiments of the electric switch, 
         FIG. 7  is a bottom view in perspective of a contactor carriage, 
         FIG. 8  is a view in perspective of a weak-current contactor element, 
         FIG. 9  is a view in perspective of a strong-current contactor element. 
     
    
    
     DETAILED DESCRIPTION 
     In these figures, identical elements bear the same reference numbers. 
       FIGS. 1 and 2  illustrate a portion of an electric switch  1  of a motor vehicle, such as that of an assembly of controls beneath the steering wheel of a motor vehicle. 
     The switch  1  comprises a contactor carriage  3  mounted so as to be able to move in translation, for example with the aid of a slide  5 , on a set of conductive electric tracks  7  of a printed circuit board  9  (see  FIG. 2 ). 
     The movement in translation of the contactor carriage  3  establishes, according to a command of a user, an electric contact for one or more predefined positions of the path of the carriage  3 . 
     At least one weak-current contactor element  11  or strong-current contactor element  12  is installed in a housing  15 ,  17 , of the carriage  3 . 
     It is therefore possible to provide a switch  1  having a strong-current contactor element  11  and a weak-current contactor element  12  ( FIG. 3 ). 
     Alternatively, it is possible to provide a switch  1  comprising a single weak-current contactor element  11  ( FIG. 4 ), or two weak-current elements  11  ( FIGS. 1 and 5 ). 
     It is also possible to provide a switch  1  comprising one or two strong-current contactor elements  12  ( FIG. 6 ). 
     The electric contact modifying the switching states is established in at least one electric contact location  13 , by friction contact of the contactor elements  11  or  12  facing the electric tracks  7 . 
     A more detailed description will now be given of the contactor carriage  3  ( FIG. 7 ), and then of the strong-current contactor element  12  ( FIG. 9 ) and weak-current contactor element  11  ( FIG. 8 ). 
     The contactor carriage  3  comprises a first housing  15  designed to receive a strong-current contactor element  12 , and a second housing  17  designed to receive a weak-current contactor element  11 , so that an electric contact is capable of being established in the location either by the installation of a strong-current contactor element  12 , or by the installation of a weak-current contactor element  11  in the associated housing  15 ,  17 . 
     It is therefore possible to have the choice either of a weak-current contactor element  11  or a strong-current contactor element  12  for the establishment of the electric contact necessary to apply the desired switching in the location  13  of the electric circuit  7 . 
     In addition, provision is made for the carriage  3  to comprise a first snap-fitting means  19  ( FIG. 7 ) designed to interact with a second complementary snap-fitting means  21  supported by the contactor element  11 , in order to attach the contactor element  11 ,  12  removably to the carriage  3 . 
     Therefore, it is possible to modify the strong-current contactor element  12  with a weak-current contactor element  11  and vice versa even though the assembly has already been carried out, also adding flexibility of production to the switch  1 . 
     The first snap-fitting means  19  advantageously comprises a protuberance or a hole. In the embodiment illustrated in  FIG. 7 , the first snap-fitting means  19  comprises a coupling protuberance. 
     The first housing  15  is defined, for example, by at least two slots  23  designed to interact with a corresponding strong-current contactor element  12 . 
     Advantageously, the strong-current contactor element  12  comprises a contactor bridge  25  ( FIG. 9 ). 
     Preferably, the contactor bridge  25  comprises two excrescences  26  capable of establishing two simultaneous electric contacts in the locations  13  ( FIG. 9 ). 
     The two simultaneous contacts make it possible to double the switching function, thereby making it possible to enhance the switching safety of the switch  1 . 
     The first snap-fitting means  21  of the strong-current contactor element  12  is advantageously formed by two complementary protuberances supported by the flanges of the bridge  25 , on the outer faces. 
       FIG. 3  shows that the strong-current contactor element  12  comprises an elastic return spring  27  of the contactor bridge  25  placed between the arch of the bridge  25  and the carriage  3 . 
     Therefore, the bridge  25  is constantly elastically pressed against tracks of the circuit  7 . 
     Returning to  FIG. 7 , it can be seen that the second housing  17  is defined by at least one slot  29  designed to interact with a corresponding weak-current contactor element  11 , such as an elastic contact strip, so that an electric contact is capable of being established in the location  13 . 
     Advantageously, provision is made to place the slots  23  of the first housing  15  parallel with the plane defined by the slot  29  of the second housing  17 , in order to gain compactness. 
     More precisely, and as can be seen in  FIG. 8 , the elastic strip  11  advantageously has a first end that can move pivotingly in the form of a fork designed to establish an electric contact. 
     The second end is designed to be housed in the slot  29  to keep the contactor element  11  in the carriage  3 . 
     The two ends join together forming an angle substantially greater than a right angle, obtained for example by folding the strip  11 . 
     Therefore, the end designed to establish an electric contact is elastically pushed against the tracks of the electric circuit. 
     Advantageously, the first end in the shape of a fork has at least two branches  31  capable of establishing two simultaneous electric contacts. 
     As in the embodiment described of the strong-current contactor element  12 , the two simultaneous electric contacts are provided in the weak-current contactor element  11  for safety of switching. 
     Preferably, each branch  31  comprises at least two contactor arms  33  and each branch  31  or contactor arm  33  has a curved end  35 . 
     The spacing between the two branches  31  depends on the spacing between the electric tracks  7  of the control device. 
     Therefore, in  FIG. 1 , the spacing between the two branches  31  is not the same for the two weak-current contactor elements  11 . It corresponds to the particular arrangement of the conductive tracks  7  of the bottom electric circuit. 
     Alternatively, the spacing is the same between the two branches  31  of two distinct elastic strips  11  mounted in the switch  1 , which makes production easier ( FIG. 5 ). 
     The first snap-fitting means  21  of the contactor element  11  is advantageously formed by at least one, and preferably two, elastic hooks capable of interacting with the coupling protuberance  19  of the carriage  3 . 
     For ease of production, the hooks are cut directly from the elastic strip  11 . 
     In an advantageous manner, provision is made, in a contactor carriage  3  comprising two contactor elements  11 ,  12 , for the first housings  15  designed for the strong-current contactor elements  12  to be situated on the edges of the carriage  3  relative to the second housings  17  designed for the weak-current contactor elements  11 , situated in the center. 
     Specifically, it is easier to arrange an elastic strip  11  housed in the second housing  17  and of which the fork is extended to the location  13 , passing over the first housing  15  than to do the reverse. 
     Therefore, a modulatable electric switching device  1  is obtained comprising a contactor carriage  3  comprising a first housing  15  designed to receive a strong-current contactor element  12 , and a second housing  17  designed to receive a weak-current contactor element  11 , so that an electric contact can be established in the location  13  either by installing a strong-current contactor element  12 , or by installing a weak-current contactor element  11  in the associated housing  15 ,  17 , making it possible to provide at will a weak-current electric contact or a strong-current electric contact, without having to completely modify the switch, and therefore the control lever containing said switch under the steering wheel.