Abstract:
The present invention relates to a dashboard indicator module comprising, in a casing, a rotary motor, an output shaft, mechanical reduction device associated with the motor, at least one electrical supply coil, electrical connection tabs linked to the coils leaving the casing and electrical contact elements, characterized in that the electrical contact elements can be fitted on the connection tabs in order to produce solderless connectors on the printed circuit or even removed from the connection tabs in order to allow the connection tabs of the motor to be soldered directly to the printed circuit.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a National Stage entry of International Application No. PCT/FR2008/000646, filed May 7, 2008, which claims priority to French application Ser. No. 07/54937 filed May 9, 2007 and French application Ser. No. 07/06930 filed Oct. 3, 2007, the disclosure of the prior applications, specification, claims, and drawings of which are incorporated herewith by reference. 
     BACKGROUND 
     1. Field 
     The present invention relates to the field of motor vehicle dashboard indicators and more particularly relates to a module consisting of a motor and electrical connection means—so-called connectors or contacts—intended to be fixed on a printed circuit that includes all the electronic components required for the operation of the motor. 
     2. Background 
     Generally, dashboard pointers (tachometer, gauge) for motor vehicles are actuated by so-called step by step electromagnetic motors. Such motors are for example disclosed in patent FR 2742940 or patent FR 2859323. Such motors are fixed behind the dashboard on a printed circuit on which the electrical supply tracks and all the electronic components intended to operate the motor are fixed. The printed circuit is fixed in the dashboard instrument and the motor is fixed to the printed circuit. The electric connection of the motor is generally carried out through the soldering of electric connection tabs integral with the motor together with the printed circuit tracks. Soldering the connectors to the printed circuit and positioning the motor connection tabs in such connectors can also be considered. Patent FR 2885739 of the applicant discloses a method of this type. 
     Nevertheless, all the prior art methods have some disadvantages. First, both the connectors and the casing containing the motor must be positioned on the printed circuit. Thus, the connectors must be positioned on the printed circuit and then the casing must be positioned on the printed circuit with the casing connected to the connectors. In addition, prior art techniques do not allow the easy removal and reutilization of the motor on another printed circuit with the same electric connection means in a simple and efficient way. 
     Solutions already exist in the prior art showing motors with deformable connection tabs. Upon the positioning of the motor on the printed circuit, such particular connection tabs come in contact with electric contact surface areas on the printed surface and thus are deformed in order to provide the electric contact. Thus, the motor is not soldered onto the circuit. 
     However, such solutions require a modification to the original motor solution that contains very special connection tabs. This modification requires a different product in parallel with the original apparatus having straight connection tabs affixed to the motor and requiring solders on the printed circuit. Depending on the application or the targeted client, the production tools are doubled with this modification and manufacturing the assembly of two motors is expensive. 
     SUMMARY 
     The invention of the present disclosure intends to remedy this problem with the described electric motor module that can be used with connection tabs being soldered on the printed circuit or with solderless connectors using contacts added onto the connection tabs, depending on the type of connection requested by a client. 
     More particularly, one object of the present invention is to provide a dashboard indicator module including, in a casing, a rotary motor, an output shaft, mechanical reduction means associated with the motor, at least one electric supply coil, and electric connection tabs associated with the coils leaving said casing and electric contact elements, where the contact elements can be fitted on the connection tabs in order to provide solderless connections to the printed circuits or can be removed from the connection tabs in order to allow the connection tabs of the motor to be directly soldered to the printed circuit. 
     Another object of the invention is to provide electrical contact elements composed of a first part in mechanical and electrical connection with said tabs and a second free part intended to come in mechanical and electrical contact with a voltage-supplied surface of a printed circuit that supports said module and is used for supplying said motor with voltage. 
     Another object of the present invention consists in providing is to provide a module including a motor and electric contacts integral with the motor that does not require soldering the motor to a printed circuit—or any soldering at the printed circuit level. This provides for easy removal of the motor positioned on the printed circuit. 
     Another object of the present invention is to provide a module including a motor, electrical contacts, and mechanical rivets that are independent of the printed circuit and that can adapt to different types of printed circuits. 
     Thus, the printed circuit intended to receive the indicated module described herein provides electrical or mechanical fastening means, the electrical components required for steering the motor, and holes to enable the passage of the electrical and mechanical contacts of the module. 
     In addition, the motor provides electrical connection tabs in the form of axes or pins and electrical contacts that are mechanically fixed or countersunk on such tabs. Soldering the electrical contacts with the tabs can also be considered. 
     The shape of the electrical contacts can be any shape (e.g. a spiral shape), and may include a first part ensuring the electric contact of an element with the motor connection tab and a second part oriented toward the printed circuit to link the electrical connection area of the printed circuit to the motor connection tab. The shape of this contact must also allow for the deformation thereof upon the positioning of the motor on the printed circuit. 
     The mechanical retention of the motor on the printed circuit can be provided by deformable rivets or by any other method known by those of ordinary skill in the art. 
     Further, upon the mechanical fastening of the motor, the electrical contact elements may deform and thus act as a spring. When in this compressed position, a force is applied onto the printed circuit and onto the motor casing. Because the rivets may provide for mechanical retention of the motor on the printed circuit, this force applied by the spring may provide reliable electric contact. 
     Thus, described herein is a motor module and a reliable and independent electrical contact that can adapt to various printed contacts and can be positioned on and/or removed from the printed circuit at any time. 
     In a non-limiting aspect, the motor can provide cavities close to the electrical connection tabs that allow the positioning of the lower face of the motor casing onto the printed circuit. The module can also include pads on which the motor may rest. With either solution, the motor may be fixed in a stable way to the printed circuit and may be unaffected by possible vibrations during motor operation. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
       Understanding the invention may be aided by reference to the appended drawings, in which: 
         FIG. 1  shows a cross-sectional view of a prior art module; 
         FIG. 2  shows an exemplary module according to the invention, formed of a motor in its casing and electrical contacts associated with the motor connection tabs; 
         FIG. 3  shows a printed circuit intended to receive the module shown in  FIG. 2 ; 
         FIG. 4  shows an exemplary electrical contact used in the module of the invention in a non-deformed condition; 
         FIG. 5  shows an exemplary electrical contact used in the module of the invention according to  FIG. 3  in a deformed condition; 
         FIG. 6  shows a top view of the module where the contact shown in  FIGS. 4 and 5  is fixed on an electrical connection tab of the motor; 
         FIG. 7  shows another exemplary electrical contact used in the module of the invention in a non-deformed condition; 
         FIG. 8  shows another exemplary electrical contact used in the module of the invention according to  FIG. 7  in a deformed condition; 
         FIG. 9  shows another exemplary electrical contact used in the module of the invention; 
         FIG. 10  is a cross-sectional view of a module according to the invention including contacts as shown in  FIGS. 4 ,  5  and  6  close to a printed circuit; 
         FIG. 11  is a cross-sectional view of a module according to the invention including contacts as shown in  FIGS. 4 ,  5  and  6  in contact with a printed circuit; 
         FIG. 12  is a cross-sectional view of a module according to the invention including contacts as shown in  FIGS. 7 and 8 , close to a printed circuit; 
         FIG. 13  is a cross-sectional view of a module according to the invention including contacts as shown in  FIGS. 7 and 8  in contact with a printed circuit; 
         FIG. 14  is a cross-sectional view of a module according to the invention including contacts as shown in  FIG. 9  close to a printed circuit; 
         FIG. 15  is a cross-sectional view of a module according to the invention including contacts as shown in  FIG. 9  in contact with a printed circuit; 
         FIG. 16  is a printed circuit intended to receive a module according to the invention including contacts as shown in  FIG. 9 ; 
         FIGS. 17   a  and  17   b  show another exemplary electrical contact used in the module of the invention; 
         FIG. 18  is a cross-sectional view of a module according to the invention including contacts as shown in  FIGS. 17   a  and  17   b  close to a printed circuit; and 
         FIG. 19  is a cross-sectional view of a module according to the invention including contacts as shown in  FIGS. 17   a  and  17   b  in contact with a printed circuit. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  shows a prior art embodiment that includes a motor (e.g. an electromagnetic motor) in a casing  7   b  and electrical connection tabs  14  associated with the motor coils, having a nonlinear J-shape. This motor is intended to be fixed on a printed circuit and connection tabs  14  are intended to be deformable to provide electrical contact with the printed circuit. However, this embodiment requires apparatuses that are much different from those disclosed herein. Specifically, the prior art provides apparatuses that include straight connection tabs that must either be soldered or nonlinear tabs that are not soldered. Thus, according to the prior art, these two solutions must be produced and utilized independently. 
       FIG. 2  shows a module  1  according to the present disclosure. It is composed of a clamped plastic casing  7  containing an electromagnetic motor, and a set of reducer gears moving in rotation on an axis  6 , and a hollow axis intended to receive a pointer. Such pointer may be used for providing, on the dashboard of a motor vehicle, information regarding the motor vehicle&#39;s speed level or regarding any other parameter. This casing  7  may include two deformable rivets  5  which are used for the mechanical behavior of the casing  7  on the printed circuit  8  intended to receive it. It also includes resting pads  4  on which the module  1  may rest and straight electrical connection tabs  3 . Such connection tabs  3  are the electrical connections of the motor coils inside the casing  7 . In addition, two pairs of tabs  3  may be utilized for a two-coil, two phase motor. Electrical contacts may be mechanically countersunk or soldered on such tabs. Furthermore, module  1  be positioned on a printed circuit  8  ( FIG. 3 ). Additionally, where the contacts  2  of the tabs  3  are removed, module  1  can be connected to the printed circuit  8  by directly soldering the tabs  3  to the printed circuit  8 . 
     As  FIG. 3  illustrates, in addition to the electronic elements required for driving the motor, printed circuit  8  may contain a first series of holes  9  intended to receive the deformable mechanical rivets  5  ( FIG. 2 ). Once such rivets  5  are positioned through the holes  9 , they may become deformed to provide solid retention of the module  1  on the printed circuit  8 . This circuit  8  also shows a second series of holes  10  intended to receive the electrical connection tabs  3 , which may pass through the holes  10  without any physical contact. Contact surface areas  11 , which receive the contacts  2  of the module  1 , may be positioned close to such holes  10 . When positioning the module  1  on the printed circuit  8 , the rivets  5  provide the mechanical retention, the resting plots  4  provide the stability, and the deformable contacts  2  provide the electrical contact between the connection tabs  3  and the contact surface area  11  through a spring effect. Without the contacts  2 , the tabs  3  of the module  1  may be directly soldered on the contact surface areas  11 . 
       FIG. 4  illustrates a first embodiment of a contact element  2  in an uncompressed and non-deformed condition. In this first embodiment, the contact  2  takes the shape of a conical and helicoidal spring and includes two significant parts. The first part  12  is intended to the connection tab  3 , either through mechanical countersinking or soldering. The second part  13  is intended to provide electrical contact with the contact surface area  11  of the printed circuit  8 . 
     During the positioning of the module  1  on the printed circuit  8 , this contact element  2  becomes deformed and thus provides reliable electrical contact between the printed circuit  8  and the motor of the module  2  through spring forces exerted by the deformed or compressed contact element. 
       FIG. 5  shows the contact element  2  according to  FIG. 4  but in a deformed condition after placing module  2  on the printed circuit  8 . In such a deformed condition, second part  13  may be in contact with the contact surface area  11  of the printed circuit  8  and the windings of the contact  2  may be closer to each other, such as in a joint winding configuration. 
     In addition, when the contact  2  is provided on the connection tab  3 , these elements may be arranged under the module as shown in  FIG. 6 . In this exemplary arrangement, connection tab  3  may be in physical contact with the contact element  2  at the level of the first part  12  previously described. 
       FIG. 7  shows a contact element  2  in a second embodiment that displays elastic properties and includes two distinct parts  12  and  13  intended to come into contact with the connection tab  3  of the motor and with the electrical contact surface area  11  of the printed circuit  8 , respectively. In  FIG. 7 , the contact element  2  may be in a non-deformed condition.  FIG. 8  shows a contact element  2  in a deformed condition, such as after assembling the module on the printed circuit  8 . 
       FIG. 9  shows a contact element  2  in a third embodiment with two characteristic parts  12  and  13 . In addition,  FIGS. 10 and 15  show cross-sectional views of the module close to, or in contact with, the printed circuit. 
     In  FIGS. 10 ,  12  and  14 , the module is close to the printed circuit  8  prior to being fitted thereto. The contact  2  is positioned to be integral with the connection tab  3 , which may begin protruding through the hole  10  of the printed circuit  8 . 
     In  FIGS. 11 ,  13  and  15 , the module is fitted on the printed circuit  8 . The rest pads  4  may be in contact with the printed circuit  8  and the contact elements  2  may be in a deformed condition, providing electrical power to the motor through contact elements  2 . Furthermore, when removing the contacts  2  from the tabs  3 , the tabs  3  may be directly soldered to the printed circuit  8 . 
       FIG. 16  shows the printed circuit  8  intended to receive the contact element  2  in the third embodiment shown in  FIGS. 9 ,  14  and  15 . 
     In addition, the elements of the printed circuit of  FIG. 3  can receive the contact elements in the first and second embodiments. The relative position of the holes  10  for the passage of the tabs  3  and complex surface areas  11  is one difference between the printed circuits of  FIGS. 3 and 16 . On the printed circuit of  FIG. 3 , the holes  10  are in the middle of the contact surface area  11  in relation to the configuration of the contact elements  2  in the first and second embodiments, whereas the printed circuit  8  of  FIG. 16  shows holes  10  which are at the side of the contact surface area  11  in the third embodiment. 
       FIGS. 17   a  and  17   b  show another example of an electric contact  2  in a tubular form for easy soldering on the printed circuit  8 . A first part  12  is intended to come in contact with the connection tab  3  through a spring effect. A second part  13  provides the electronic contact with the printed circuit  8  in the form of wings, the number of such wings varying and having various forms as can be seen in  FIGS. 17   a  and  17   b.    
       FIG. 18  shows this contact  2  fitted on an electric connection tab  3  in a cross-sectional view showing the contact  2  close to the printed circuit  8 . 
       FIG. 19  shows the contact  2  mounted on the electrical connection tab  3  and positioned on the printed circuit  8 . The geometry of contact  2  is such that it rests, through wings  13 , on casing  7  on the upper part of the wings  13 , and on the electrical contact area  11  of the lower part thereof. 
     An advantage of this contact  2  is that it can provide the electrical contact either through the contact of the wings  13  on the electrical contact areas  11  of the printed circuit  8  or through the connection of the contact body  2  inside the hole  10 , which may be metalized. Therefore, contact  2  is appropriate for both printed circuits  8  with single faces and/or double faces. 
     Another advantage of this contact  2  of  FIGS. 17   a  and  17   b  is that it is circular, which ensures that any effects caused by micro-vibrations in operation are mainly distributed in an axial direction and not a radial direction, thus making it possible for the contact  2  to perform reliably over time without causing oxidation. 
     The illustrations shown in this document are strictly exemplary and in no way represent limiting embodiments. Furthermore, one may modify the shape of the contact elements  2  or any other element mentioned in this document without departing from the scope of the invention.