Abstract:
The invention concerns a control panel for a motor vehicle system comprising a housing supporting at least a double control unit formed by two rotating knobs arranged projecting relative to the housing and respectively coupled with two shafts, which are capable of being connected to the system elements. One of the shafts bears a coaxial worm screw for driving in rotation a toothed wheel about an axis orthogonal to the shaft axis, said toothed wheel capable of being functionally coupled with a first member of the system, while the other shaft is parallel to the first shaft and is capable of being functionally coupled with a second member of the system. The invention is particularly applicable to heating-ventilating and/or air conditioning systems.

Description:
BACKGROUND OF THE INVENTION 
     The invention relates to a control panel for a motor vehicle system, such as, for example, a heating, ventilating and/or air conditioning system for the passenger space of the vehicle. 
     It more particularly relates to a control panel of the type comprising a housing supporting at least one double control unit formed by two coaxial rotating knobs disposed projecting relative to the housing and respectively coupled with two shafts, which are capable of being connected to the elements of the system. 
     Control panels of this type are already known, in particular from the publication FR 2 756 067 by the Applicant, or also from publications FR 2 631 719, FR 2 693 408 and U.S. Pat. No. 5,093,764. 
     BRIEF SUMMARY OF THE INVENTION 
     One of the objects of the invention is to reduce the spatial requirement of a control panel of the above-mentioned type so as to be able to integrate it more easily in a dashboard of a motor vehicle. 
     Another object of the invention is to obtain a control panel which has a narrow facade to form a control panel of the extra-flat type. 
     For this purpose the invention proposes a control panel of the type defined in the introduction, in which one of the shafts, or first shaft, bears a coaxial worm screw capable of driving in rotation a toothed wheel around an axis orthogonal to the axis of the shaft, the said toothed wheel being capable of being functionally coupled with a first element of the system, and in which the other shaft, or second shaft, is parallel to the first shaft and is cable of being functionally coupled to a second element of the system. 
     The joint use of a worm screw and of a toothed wheel contributes towards reducing the spatial requirement of the control panel, given that this screw and this wheel can occupy a confined space which is relatively flat. 
     By the expression “toothed wheel” is understood both a complete toothed wheel as well as a toothed sector. 
     Other optional complementary or alternative characteristics of the invention are given below: 
     the one of the first shaft and of the second shaft is coaxial with the control knobs. 
     The second shaft is coaxial with the control knobs and is directly driven by one of the knobs, called “second knob”, whereas the first shaft is indirectly driven by the other knob, called “first knob”. 
     The first knob is fixed in rotation with an annular gear which meshes with a toothed pinion fixed in rotation with the worm screw. 
     The toothed wheel is fixed in rotation with a control lever. 
     The control lever is connected to a control cable, which is connected to the first element of the system. 
     The axis of the toothed wheel is substantially perpendicular to a bottom wall of the housing. 
     The second shaft has a free end which is directly connected to the second element of the system. 
     The second shaft has a free end which is indirectly connected to the second element of the system. 
     The second element of the system is a rotary switch. 
     The panel comprises a double control unit and at least one cursor control disposed projecting relative to the housing. 
     The panel comprises a double control unit and two cursor controls disposed on either side of the double control unit. 
     The panel comprises two double control units having parallel axes. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the following description, given only by way of example, reference is made to the attached drawings, in which: 
     FIG. 1 is a perspective view of a control panel according to a first embodiment of the invention; 
     FIG. 2 is a bottom view of the control panel of FIG. 1; 
     FIG. 3 is an exploded view of the control panel of FIGS. 1 and 2, and 
     FIG. 4 is a bottom view of a control panel according to a second embodiment of the invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Reference is firstly made to FIG. 1 which shows a control panel  10  according to the invention that is intended to form part of a system for heating-ventilating and/or air conditioning the passenger compartment of a motor vehicle. 
     This panel comprises a housing  12  essentially comprising a bottom wall  14  forming a plate with a general rectangular shape and a facade  16  intended to be embedded in the dashboard (not represented) of the vehicle. 
     The control panel  10  comprises a double control unit  18  disposed substantially in the central portion of the facade  16  and comprising two coaxial rotary knobs, i.e. a first knob  20 , also called “outer knob”, and a second knob  22 , also called “inner knob”. These two knobs are disposed projecting relative to the facade  16  of the control panel. In the example, knob  20  serves to regulate the temperature of the air sent into the passenger compartment, whereas knob  22  serves to regulate the speed of the pulsing device (not represented) serving to pulse air into the passenger compartment. 
     As can be seen better on FIG. 3, knob  22  is connected to a shaft  24 , also called “second shaft”, which successively passes through a disk  26  bearing marks and a drum  28  connected with an annular gear  30  bearing internal toothing. The drum  28  is guided by a cylindrical bearing surface  32  forming an integral part of the housing  12 . The shaft  24  has a free end  34  which is provided to be directly coupled to a switch  36  which forms an element of the system and serves to regulate the rotational speed of the pulsing device (not represented) which the system has. For this purpose, the end  34  of the shaft  24  is capable of being received in a muff  38  which the switch  36  has. 
     The knob  20  (FIGS. 1 and 3) comprises an index  40  enabling its adjustment on the drum  28 . Thus, the annular gear  30  may be driven in rotation in one direction or in the other direction by the knob  20 . 
     The annular gear  30  (FIGS. 2 and 3) mesh with a toothed pinion  42  fixed on a shaft  44 , called “first shaft”, on which a worm screw  46  is also fixed. The shaft  44  is held in position by a clamp  47  fixed to the base wall  14 . Thus, the first knob  20  and the second knob  22  are capable of driving in rotation respectively a first shaft  44  and a second shaft  24 , which extend parallel to one another. The driving of the shaft is performed with a transmission ratio, whereas the driving of the shaft  24  is direct. 
     The worm screw  46  is capable of cooperating with a toothed sector  48  (FIGS. 2 and 3) which is capable of pivoting around an axis  50  which extends orthogonally to the axis of the shaft  44 . Moreover, this axis  50  extends perpendicularly to the plane of the base wall  14 , with the result that the worm screw  46  and the toothed wheel  48  occupy a relative flat and narrow space and which may be at least partially contained in the thickness of the base wall. 
     The toothed sector  48  is fixed in rotation with a lever  52  comprising a notch  54  capable of receiving a pin  56  provided at one end of a control cable  58  which passes through a sleeve  60  (FIG.  1 ). The other end of the cable is intended to operate a regulating valve (not represented) serving to adjust the temperature of the air sent into the passenger compartment. 
     The control panel of FIGS. 1 to  3  also comprises two cursor controls  62  and  64  disposed on either side of the double control unit  18 . The control  62  comprises an actuating pull  66  passing through a slot  68  of the facade and actuating a lever  70  mounted to rotate around an axis  72  and fixed in rotation with another lever  74 . This lever  74  has a notch  76  capable of receiving a pin  78  provided at the end of a cable  80  passing through a sleeve  82 . The cable  80  is capable of actuating, in the example, an air intake control (not represented) serving to supply the system either by the outer air drawn outside the passenger compartment, or the recirculated air drawn inside the passenger compartment. 
     The control  64  comprises an actuating pull  84  passing through a slot  86  of the facade. This actuating pull operates a lever  88  pivoted around a shaft  90  and integral with another lever  92 . The latter has a notch  94  capable of receiving a pin  96  mounted at the end of a control cable  98  passing through a sleeve  100 . The other end of the cable  98  is capable of being connected to another element of the system, in the example to a control serving to distribute air between different distribution nozzles opening into the passenger compartment. 
     Thus, as can be seen better in FIGS. 1 and 2, all the above-mentioned control elements occupy a small space and enable a control panel of the “extra flat” type to be formed, which can easily be housed in the dashboard of the vehicle. 
     As can be seen more particularly in FIG. 3, the housing of the control panel also comprises two light boxes  102  and  104  which are capable of receiving respective bulbs  106  and  108 , these light boxes being masked by respective screens  110  and  112  bearing different symbols or marks. 
     In the embodiment of FIG. 4, to which reference is now made, the control panel comprises two double control units  18   a  and  18   b  that respectively comprises two coaxial knobs  20   a  and  22   a,  and two coaxial knobs  20   b  and  22   b.  The knob  22   a  directly drives a shaft  24   a  whereas the knob  20   a  drives a worm screw  46   a  around an axis parallel to that of the shaft  24   a.    
     In a corresponding manner, the knob  22   b  directly drives a shaft  24   b,  whereas the knob  20   b  indirectly drives a worm screw  46   b  around an axis parallel to that of the shaft  25   b.  As can be seen in FIG. 4, the respective axes of the shaft  24   a,  of the worm screw  46   a,  of the shaft  24   b  and of the worm screw  46   b  are parallel and situated in the same plane, which corresponds to the general plane of the base plate of the housing. The shaft  24   a  directly drives a switch  36  similar to that previously described. The worm screw  46   a  meshes with a toothed wheel  48   a  locked in rotation with a lever  52   a  which acts on a cable  98  similar to that described in the embodiment of FIG. 1 to  3 . 
     The shaft  24   b  is equipped with a toothed pinion  114  which meshes with a toothed sector  116  fixed in rotation with a lever  118  that actuates a cable  120  passing though a sleeve  122 . 
     The worm screw  46   b  meshes with a toothed sector  48   b  fixed in rotation with a lever  52   b  that actuates a cable  124  passing through a sleeve  126 . 
     It will be understood that the cables  120  and  124  can play the role of cables  80  and  98  of the previous embodiment, the difference being that these cables are operated not by pull mechanisms, but by a coaxial double control unit. 
     The embodiment of FIGS. 1 to  3  consequently uses one double rotary control unit and two pull controls to perform a total of four controls. This embodiment has various advantages, including a limited height requirement and a gain in facade surface. The speed multiplication between the control knob and the endless screw enables a very gentle and pleasant control sensation to be experienced. Moreover, the use of a control unit comprising an endless screw and toothed wheel enables there to be an irreversible control. 
     The embodiment of FIG. 4 enables the use of two double control units to perform a total of four controls. These two double control units are similar to those described in the first embodiment of the invention. Therefore four controls are produced on two parallel axes. The main advantages involve the limited height and width requirement, which enables a gain in facade surface to be achieved. 
     Furthermore, the use of these double knobs and their integration in control panels of the extra-flat type allow important gains with respect to the decoration which is then made at the level of the knobs. 
     It may also be envisaged performing the direct control by a wheel and worm screw system, with a knob at the centre connected to an axle comprising a worm screw meshing with a pinion connected to a lever. 
     Of course, the invention is not limited to the embodiments that were previously described by way of example and it extends to other variants.