Patent Publication Number: US-9847609-B2

Title: Electrical assembly with leaktight connection

Description:
The present invention relates to an electrical assembly comprising a removable part and a base part intended to be fixed together in a separable manner. 
     The establishment of a leaktight electrical connection, meeting standard IP67 in particular, is usually effected by connecting a male part to a female part, leaktightness being ensured by the presence of one or more gasket seals. In the absence of connection, the leaktight fixing of a stopper on the idle part is necessary. 
     Another known solution consists in circumventing the necessity for the stopper through the presence of a manually actuatable switch, to turn off the idle part. The establishment of the electrical connection is done in these two solutions in two steps, and poor manipulation may give rise to discomfort, or indeed a risk for the operator. 
     Devices comprising an apparatus and a battery support cooperating with the apparatus by leaktight connection of complementary contacts are known from the publications U.S. Pat. No. 5,822,808 and JP 8 145 678. 
     A leaktight battery support intended to cooperate with an apparatus with electrical connection via leaktight contacts is known from application US 2002/0018343, the battery support comprising a switch cutting the electrical power supply when the support is not assembled with the apparatus, actuatable by a magnetic force. 
     A need exists to simplify the establishment of a leaktight and reliable electrical connection by assembly of two removable parts, while limiting the operator risks related to possible poor manipulation, as well as the risks of corrosion of the contact surfaces in case of exposure to a damp or liquid environment with these surfaces under live voltage. 
     SUMMARY 
     The invention is aimed at meeting this need and its subject is, according to one of its aspects, an electrical assembly, comprising:
         a base part; and   a removable part configured to be fixed in a removable manner on the base part,       

     the base part comprising:
         a flexible membrane delimiting, at least in part, a leaktight internal volume,   at least one movable electrically conducting element, carried by the membrane, and extending, at least in part, in the internal volume, and   at least one internal electrical contact disposed in the internal volume under the movable conducting element,       

     the movable conducting element contacting, during a deformation of the membrane related to the assembly of the removable part on the base part, the internal electrical contact for the establishment of an electrical connection between them, and being distant from the internal electrical contact in the absence of fixing of the removable part on the base part. 
     Contact between the movable conducting element and the internal electrical contact, during assembly, allows the flow of an electrical current. 
     Before assembly, there is no electrical connection and no external element of the base part is under voltage. After assembly, there is creation of an electrical connection which allows the flow of an electric current and which is made safe since it is protected by the assembly. At no time is the user exposed to a risk of contact with an element that may generate an electric discharge. 
     The expression “in a removable manner” is understood to mean that the removable part can be assembled and disassembled from the base part at will, joining being effected for example by interlocking, in particular with friction, snap-fastening, screwing, interlinking of bayonet type, intervention of at least one third party element, cooperation of shapes, magnetic assembly or yet otherwise. 
     The expression “leaktight internal volume” is understood to mean that the assembly comprises a cavity delimited by surfaces that do not allow the penetration of water from outside the base part. 
     The invention finds most particularly to apply when the internal electrical contact is linked to an electrical device such as an electrical generator, in particular low-voltage, for example less than or equal to 24V, or an electrical receiver. 
     Contact between the movable conducting element and the internal electrical contact is, preferably, accompanied by an elastic deformation, for example of a support carrying the internal electrical contact and/or an elastic deformation of this internal electrical contact. This makes it possible to obtain good contact pressure, even in the presence of manufacturing tolerances. 
     The internal electrical contact can consist of a helical or leaf spring, in particular flexible leaf folded back on itself. 
     Preferably, the movable conducting element and the internal electrical contact can, in the absence of deformation of the membrane, be a distance apart of at least 0.3 mm, for example between 0.5 and 2 mm, thereby reducing the risk of accidental contact and of electrostatic discharge. 
     The flexible membrane deforms elastically and it is preferably made of elastomer or metal, in particular polyurethane, rubber or silicone. 
     The movable conducting element can be made of metal, in particular bronze, aluminium or stainless steel or of conducting plastic, for example filled with carbon or with graphite. 
     The assembly preferably meets standard IP67 and/or ATEX directives 1999/92/CE (use in zones 0, 1, 20 and 21 in particular) and/or ATEX directives 94/9/EC (class 1 and class 2). The mode of protection of the assembly is preferably enhanced safety “e”. 
     Preferably, the movable conducting element passes through the membrane. The movable conducting element being fixed in a leaktight manner on the membrane, it can delimit in part with the flexible membrane the leaktight internal volume. 
     When the movable conducting element is a through element, the removable part can comprise an external connection element designed to cooperate electrically with this movable conducting element when the removable part is fixed on the base part. This electrical contact can be effected by simple bearing, without keying. The internal electrical contact can be linked to a first electrical device, in particular to at least one of an electrical generator and of an electrical receiver, and the external connection element is linked, at least when the removable part is fixed on the base part, to a second electrical device, in particular to the other of the electrical generator and of the electrical receiver. 
     Preferably, the electrical contact between the external connection element and the movable conducting element is effected, during the assembly of the removable part on the base part, before the electrical contact between the movable conducting element and the internal electrical contact. 
     Preferably, at least one of the removable part and of the base part comprises a relief, preferably a protruding relief, which bears, in a leaktight manner, on the other of the removable part and of the base part. This relief can have the shape of a protruding annulus which can be moulded with the membrane or come to bear on top. As a variant, the removable part and the base part can each exhibit a relief, at least one of which is moulded with the membrane. 
     The removable part can come to bear on the membrane exclusively through the relief. The relief allows in particular, during assembly, the removable part to bear on the flexible membrane of the base part so as to deform it and allow electrical connection between the movable conducting element and the internal electrical contact. 
     The membrane make it possible to obtain a leaktight electrical connection at the level of the bearing between the removable part and base part without the use of add-on gasket seals. 
     The membrane can then play a dual function, of establishing a leaktight connection on the one hand and of support of the movable conducting element or elements on the other hand. 
     The membrane can, during its deformation, form, at its periphery, a bead delimiting a cup. 
     Preferably, the leaktightness of the contact defined by the aforementioned relief is achieved before the contact between the movable conducting element and the internal electrical contact. 
     The external connection element can be linked electrically in a permanent or non-permanent manner to the second electrical device. 
     When the connection is not permanent, the external connection element can be designed to move and to contact, when the removable part is fixed on the base part, an additional electrical contact for the establishment of an electrical connection between them, this additional contact being linked in a permanent manner to the second electrical device. 
     In particular, the removable part can be of similar construction to the base part, and comprise in particular:
         a flexible membrane delimiting, at least in part, a leaktight internal volume,   at least one movable electrically conducting element, carried by the membrane, and passing through the membrane, and   at least one internal electrical contact disposed in the internal volume under the movable conducting element.       

     The movable conducting element contacts, during a deformation of the membrane related to the assembly of the removable part on the base part, the internal electrical contact for the establishment of an electrical connection between them, and is distant from the internal electrical contact in the absence of fixing of the removable part on the base part. 
     The flexible membrane of the removable part can, by deforming, form, at its periphery, a bead delimiting a cup. 
     Preferably, during assembly of the removable part on the base part, the membranes of the base part and of the removable part each deform to form a bead, the beads of the base part and of the removable part coming into contact with one another so as to delimit an intermediate volume, in particular a leaktight intermediate volume, in which contact is established between the movable conducting element of the base part and the movable conducting element of the removable part. 
     The base part can comprise at least two distinct movable conducting elements and at least two distinct electrical contacts, each movable conducting element contacting, when the removable part and the base part are assembled, a respective internal electrical contact for the establishment of an electrical connection between them. 
     The internal electrical contacts are for example linked to the two terminals of an electrical generator. 
     The two movable conducting elements can be through elements, the removable part comprising at least two distinct external connection elements intended to each come into contact with one of the movable conducting elements when the removable part is fixed on the base part. 
     At least one of the removable part and of the base part can be linked to an electrical source or an electrical receiver and the other of the removable part and of the base part be linked to the other of the electrical source and of the receiver. The assembly of the removable part and the base part then makes it possible to electrically power the electrical receiver with the electrical source. 
     In a variant, the base part comprises at least two internal electrical contacts, the movable conducting element contacting, during the fixing of the removable part on the base part, the two internal electrical contacts so as to define between them a closed electrical circuit. The assembly then plays the role of switch. 
     The base part can comprise an external connector element linked electrically in series with the internal electrical contacts when the electrical circuit is closed. The electrical connection is effected during the contact of the movable conducting element with the internal electrical contacts. 
     The subject of the invention is further a treatment apparatus comprising a hand piece defining the base part of an assembly according to the invention and an accessory defining the removable part. The accessory is, when fixed to the hand piece, powered electrically from an electrical source internal to the hand piece, via the said assembly. 
     The subject of the invention is also a base part of an electrical assembly according to the invention, such as defined hereinabove, the movable conducting element being a through element. 
     The subject of the invention is further a base part of an electrical assembly according to the invention, such as defined hereinabove, the internal electrical contact exhibiting an inherent elasticity, consisting in particular of a leaf folded back on itself. 
    
    
     
       The invention may be better understood on reading the following detailed description of non-limiting illustrative examples thereof and on examining the appended drawing, in which: 
         FIGS. 1 and 2  are schematic sections through an assembly according to the invention, respectively before and after assembly of the movable part on the base part, 
         FIGS. 3 and 4  are schematic sections through a variant of assembly according to the invention, respectively before and after assembly of the movable part on the base part, 
         FIGS. 5 and 7  are schematic sections through variants of assembly according to the invention, before assembly of the movable part on the base part, 
         FIG. 6  corresponds to  FIG. 5  after assembly of the movable part on the base part, 
         FIGS. 8 and 9  are schematic sections through a variant of assembly according to the invention, respectively before and after assembly of the movable part on the base part, 
         FIG. 10  is an exploded view of the variant of  FIGS. 8 and 9 , 
         FIGS. 11 to 13  are schematic sections through different variants of the movable conducting element according to the invention, and 
         FIGS. 14 and 15  represent parts of an exemplary assembly according to the invention, relating to a skin treatment apparatus. 
     
    
    
     Represented in  FIG. 1  is an electrical assembly  1  comprising a base part  20  and a removable part  10  configured to be fixed in a removable manner on the base part  20 . 
     The base part  20  comprises a support  21  exhibiting an opening  81 , closed by a flexible membrane  22  defining at least in part, with the remainder of the base part  20 , a leaktight internal volume  24 . An internal electrical contact  28  is present under the membrane  22 . The latter carries a movable conducting element  25 , which emerges at least in part into the leaktight internal volume  24 . 
     As illustrated in  FIG. 1 , when the removable part  10  and the base part  20  are not assembled, the movable conducting element  25  and the internal electrical contact  28  are a distance d apart. 
     As illustrated in  FIG. 2 , when the removable part  10  comes into contact, in particular through a relief  19 , with the base part, it exerts a pressure on the membrane  22  which deforms. This deformation causes the movable conducting element  25  to touch the internal electrical contact  28 . 
     An intermediate volume  38 , being delimited by the relief  19 , is defined between the membrane  22  and the removable part  10 . 
     The intermediate volume  38  is, preferably, leaktight, the bearing of the relief  19  on the membrane  22  being of closed contour. 
     The membrane  22  can be made of elastomer or of metal, in particular of polyurethane, rubber or silicone. 
     The membrane  22  can be overmoulded in a leaktight manner on the support  21 . As illustrated in  FIG. 1 , the flexible membrane  22  can exhibit at its periphery a rim  26  bearing on the edge of the opening  81  of the support  21 , which aids in particular the membrane  22  to remain in the opening of the support  21  when the removable part  10  exerts a pressure on the membrane  22 . 
     The hardness of the membrane  22  is preferably between 5 Shore A and 75 Shore A. 
     The membrane  22  can comprise one or more reliefs, not represented, facilitating its deformation and/or allowing better contact with the removable part  10 . 
     The movable conducting element  25  can consist of any suitable material, in particular metallic or a conducting plastic, for example filled with carbon, preferably with bronze, aluminium, or stainless steel. 
     In the example illustrated, the movable conducting element  25  passes through the membrane  22  in a leaktight manner and delimits in cooperation with the flexible membrane  22  the internal volume  24 . 
     The movable conducting element  25  can project or, preferably, be set back from the flexible membrane  22  by a non-zero distance e. The element  25  can be solid, as illustrated, and its external contact surface plane, concave or convex outwardly. 
     The movable conducting element  25  can, as illustrated in  FIG. 1 , exhibit an annular throat  41  in which the membrane  22  is engaged. The fixing of the membrane  22  in the throat  41  can be effected by overmoulding of the membrane  22  on the movable conducting element  25  or by force-fitting and snap-fastening of the movable conducting element  25  in a hole of the membrane  22 , provided for this effect. 
     The movable conducting element  25  can be produced in diverse forms, and for example, as illustrated in  FIG. 11 , the movable conducting element  25  can be in two parts  25   a  and  25   b  assembled together on either side of the membrane  22 , in particular by screwing, snap-fastening, or riveting. 
     In the variant illustrated in  FIG. 12 , the movable conducting element  25  is in three parts  25   a ,  25   b  and  25   c , two of which  25   a  and  25   b  define the external contact surfaces and the third of which  25   c  ensures electrical connection between the other two parts  25   a  and  25   b.    
     As a variant, as illustrated in  FIG. 13 , the movable conducting element  25  exhibits a widened end  45  bearing on one side of the membrane  22  and an opposite end pushed back on the other side of the membrane  22 . 
     As illustrated in  FIG. 1 , the internal electrical contact  28  can undergo, during the fixing of the removable part  10  on the base part  20 , an elastic deformation, by being pushed back by the movable conducting element  25 . 
     The internal electrical contact  28  can be a flexible leaf spring folded back on itself. This elasticity allows, during the fixing of the removable part  10  on the base part  20 , compensation of the play, in particular related to the manufacturing tolerances, and contact pressure guaranteeing electrical continuity. 
     In the variant illustrated in  FIGS. 5 and 6 , the internal electrical contact  28  is carried by a support  32 . 
     The internal electrical contact  28  is for example in the form of a printed circuit. The support  32  can flex during the contact of the internal connection element  28  and of the movable conducting element  25 . 
     The internal electrical contact  28  is, preferably, linked in a permanent manner to an electrical device  30 , in particular an electrical generator or an electrical receiver. 
     The removable part  10  can comprise an external connection element  15  fixed to a base  11  and intended to cooperate with the movable conducting element  25  during the fixing of the removable part  10  to the base part  20 . 
     The external connection element  15  can be protruding on the removable part  10 , while being for example situated set back with respect to the relief  19 . 
     The external connection element  15  is preferably made of metal or of a conducting plastic, for example filled with carbon, in particular of bronze, aluminium or stainless steel. It can be solid, and its external connection surface plane or outwardly convex, as illustrated. 
     The external connection element  15  is, preferably, linked to an electrical device  35 , in particular an electrical generator if the internal electrical contact  28  is linked to an electrical receiver, or to an electrical receiver if the internal electrical contact  28  is linked to an electrical generator. 
     The external connection element  15  can be linked in a permanent or non-permanent manner to the electrical device  35 . 
     Preferably, during the fixing of the removable part  10  on the base part  20 , the external connection element  15  comes into contact with the movable conducting element  25  and then the relief or reliefs  19  of the base  11  of the removable part  10  come into leaktight contact with the flexible membrane  22  and then deform it in such a way that the movable conducting element  25  comes into contact with the internal electrical contact  28 . The leaktightness of the intermediate volume  38  is ensured through the contact between the relief or reliefs of the base  11  of the removable part  10  and the flexible membrane  22  before contact between the movable conducting element  25  and the internal electrical contact  28  so as to effectively make the assembly safe in relation to the exterior environment. There is therefore an electrical connection between the external connection element  15  and the internal electrical contact  28 , which allows the current to be made to pass from the electrical generator to the electrical receiver in a watertight environment. 
     Conversely, during the separation of the removable part  10  and of the base part  20 , the physical separation of the internal electrical contact  28  and of the movable conducting element  25  is achieved before the separation of the relief or reliefs with the flexible membrane and the separation of the external connection element  15  with the movable conducting element  25 . 
     Thus the electric current flowing from the electrical generator to the electrical receiver can flow only when the assembly is totally leaktight and is therefore never in contact with the exterior environment. Electrostatic discharges can only appear in the internal volume which is leaktight with respect to the exterior medium and cannot generate any risk for the user, in particular of explosion relating to the possible explosive nature of the exterior environment. 
     Preferably, the flexible membrane  22 , under the action of the removable part  10 , deforms to form a cup  23  delimited laterally by a bead  27  formed in particular by the rim  26  bearing on the edge of the opening  81  of the support  21 . 
     Preferably, the dimensions and spaces of the elements of the assembly  1 , in particular the height h of the reliefs  19 , the distance d between the movable conducting element  25  and the internal electrical contact  28 , the distance e by which the movable conducting element  25  projects from or is set back with respect to the flexible membrane  22  and the height k of the internal connection element  15  projecting from the base  11  of the removable part  10 , are such that the contacts between the elements, during assembly of the removable part  10  and the base part  20 , occur in the order stated above. 
     In the variant illustrated in  FIGS. 3 and 4 , the external connection element  15  contacts, during the fixing of the removable part  10  on the base part  20 , an additional electrical contact  18  for the establishment of an electrical connection between them, the additional contact  18  being linked to the electrical device  35 . 
     The removable part  10  can in particular be similar to the base part  20 , the additional electrical contact  18  being an internal electrical contact, the external connection element  15  being a movable conducting element carried by a flexible membrane  12 . 
     The removable part  10  can have the same characteristics as the base part  20  detailed hereinabove. 
     Preferably, the membrane  12  of the removable part  10  has the same characteristics as the flexible membrane  22  of the base part  20 . As a variant, the membrane  12  of the removable part  10  can be different from the flexible membrane  22  of the base part  20 . 
     During the fixing of the removable part  10  on the base part  20 , the movable conducting element  15  of the removable part  10  contacts the movable conducting element  25  of the base part  20 . 
     Bringing the parts  10  and  20  together gives rise to a simultaneous deformation of the two flexible membranes  12  and  22 , which allows contact of the movable conducting elements  15  and  25  with the respective internal electrical contacts  18  and  28 . Preferably, the distance l between the external surface of the movable conducting element  15  (or  25 ) and the external part of the support  11  (or  21 ) is greater than the distance d between the movable conducting elements  15  (or  25 ) and the respective internal electrical contacts  18  (or  28 ). 
     During the deformation of the flexible membranes  12  and  22 , the latter each form a cup  13  and  23  delimited laterally by a bead  17  and  27  formed by the rim  16  and  26 . The beads  17  and  27  come into contact with one another to define between them the intermediate volume  38 . The beads  17  and  27  make it possible, by coming into contact, to ensure the leaktightness of the intermediate volume  38  so that, at the time of electrical contact, the intermediate volume  38  is totally leaktight. 
     As a variant, at least one of the two membranes  12  and  22  comprises a relief, preferably protruding, bearing, during the fixing of the removable part  10  on the base part  20 , on the other of the membranes  12  and  22  to cause the two membranes  12  and  22  to deform simultaneously. 
     In the variant illustrated in  FIGS. 5 and 6 , the base part  20  comprises at least two distinct movable conducting elements  25 , and at least two distinct internal electrical contacts  28 , each movable conducting element  25  contacting one of the internal electrical contacts  28  for the establishment of electrical contact between them. 
     Preferably, the movable conducting elements  25  are through elements and they each contact an external connection element  15 . 
     The invention is not limited to a particular number of electrical connections. 
     In the variant illustrated in  FIG. 7 , the assembly comprises three movable conducting elements  25 , three internal electrical contacts  28  and three external connection elements  15 . 
     In the variant illustrated in  FIGS. 8 to 10 , the base part  20  comprises two distinct internal electrical contacts  28 , and a movable conducting element  25 , the movable conducting element  25  contacting, when the removable part  10  and the base part  20  are assembled, the two internal electrical contacts  28  so as to define a closed circuit. The movable conducting element  25  makes it possible, after assembly, to cause the current to pass from the first to the second internal electrical contact  28 . The base part  20  plays the role of a switch actuated when the removable part  10  is fixed on the base part  20 , the removable part  10  deforming the flexible membrane  22 . 
     The movable conducting element  25  is, preferably, totally included in the leaktight internal volume  24 . 
     It is seen in  FIGS. 8 and 9  that the parts  10  and  20  can carry male and female connector elements  61 ,  62  which cooperate when the parts  10  and  20  are brought together. 
     The closing or otherwise of the circuit by virtue of the movable conducting element  25  can be used to turn on or otherwise the connector element  61 , the latter being linked, as illustrated, by a track  63  to one of the contacts  28 . 
     Thus, when the circuit is open in the absence of the movable conducting element  25 , the connector element  61  is not linked electrically to the remainder of the circuit, and when the circuit is closed, it becomes so. 
     The assembly according to the invention finds to apply to numerous sectors. 
     By way of example,  FIGS. 14 and 15  illustrate an exemplary application to an apparatus for treating the body or the face, including the hair, comprising a hand piece housing an electrical source, and exhibiting a treatment member such as a brush  90 . 
     An accessory  100  can be fitted onto the hand piece, comprising for example a member making it possible to carry out a different treatment from that of the hand piece. This accessory requires an electrical power supply. 
     The hand piece defines the base part  20  of the electrical assembly according to the invention and exhibits a membrane  22  carrying two movable conducting elements  25 . 
     Two unseen internal electrical contacts are respectively linked to the terminals of an electrical source housed in the hand piece. 
     The accessory defines the removable part  10  and carries two electrical contacts  15  intended to contact respectively the movable conducting elements  25  when the accessory  100  is fixed on the hand piece  90 , for example by snap-fastening or interlocking with friction. 
     Fitting the accessory  100  gives rise to the deformation of the membrane  22  and the establishment of an electrical connection between the elements  25  and the contacts  18 . Thus, the external contacts  15  carried by the accessory  100  can be powered by the electrical source of the hand piece. The membrane  22  ensures the leaktightness of the electrical connection. 
     In the absence of accessory  100 , the movable conducting elements  25  are not powered and the user does not risk being exposed to the voltage of the electrical source even if he accidentally touches the elements  25 . Moreover, should the hand piece be used in water, electrolysis is prevented from taking place between the elements  25 , which could sap the electrical source and oxidize the contacts. 
     The assembly  1  such as described hereinabove can also be used in a medium exhibiting risks of explosions, in particular an ATEX environment. The removable part  10  can then be changed without any particular precaution, since the risk of sparks is confined to the internal space  24 . 
     The invention is not limited to the exemplary embodiments which have just been described, whose characteristics can be combined within variants that are not illustrated. 
     One and the same apparatus can carry a plurality of membranes and of movable conducting elements such as described hereinabove, optionally being able to be linked to the same electrical devices. 
     The expression “comprising a” should be understood as being synonymous with “comprising at least one”, and “is between” is understood as including the limits, unless specified to the contrary.