Patent Publication Number: US-10312618-B2

Title: Connector terminal and manufacturing method thereof

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is the U.S. National Stage entry of International Application Number PCT/JP2016/080668 filed under the Patent Cooperation Treaty having a filing date of Oct. 17, 2016, which claims priority to Japanese Patent Application Number 2015-206055 having a filing date of Oct. 20, 2015, which are incorporated herein by reference. 
     TECHNICAL FIELD 
     The present invention relates to a connector terminal and a manufacturing method thereof, and more particularly to a slide type connector terminal used for a card edge connector and the like and a manufacturing method thereof. 
     BACKGROUND ART 
     A known card edge connector for connection with card edge terminals (board side terminals) is provided with a plurality of connector terminals each consisting of a housing having a rectangular cross section and defining an outer profile of the connector terminal so as to guide a sliding movement of the connector terminal relative to the corresponding card edge terminal, and a spring piece connected to the housing and provided with a contact portion configured to establish an electric connection with a conductive portion of the corresponding card edge terminal by contacting the same. (See Patent Document 1, for example.) 
     PRIOR ART DOCUMENT(S) 
     Patent Document(s) 
     Patent Document 1: JP2014-3007A 
     SUMMARY OF THE INVENTION 
     Task to be Accomplished by the Invention 
     In a free state of the aforementioned connector terminals or when the connector terminals are not connected to the card edge terminals, the contact portion of each connector terminal protrudes out of the housing. Therefore, at the time of assembly or the like, the spring piece could be deformed if the contact portion hits an object. A deformation of the spring piece could be a cause of a poor conduction between the connector terminal and the card edge terminal. 
     When a rubber seal member is placed in the connector for waterproofing, each connector terminal is required to be passed through a through hole formed in the seal member for passing the lead wire so that the contact portion inevitably contacts the inner circumferential surface of the through hole as the connector terminal is pushed through the through hole. Therefore, a release agent or a lubricating agent consisting of silicone oil which may be deposited on the inner circumferential surface of the through hole may be transferred onto the surface of the contact portion. A foreign matter such as a release agent and a lubricating agent deposited on the contact portion may cause a conduction failure between the connector terminal and the card edge terminal. 
     A primary object of the present invention is to prevent deformation of a spring piece of a connector terminal provided with a contact portion from deforming during assembly work, and deposition of foreign matter on the surface of the contact portion that could cause a conduction failure so that a favorable electric conduction may be ensured in a reliable manner. 
     Means for Accomplishing the Task 
     To achieve such an object, the present invention provides a connector terminal ( 10 ) configured to be electrically connected to an object terminal ( 90 ) by making a sliding engagement with a planar surface ( 92 ) including the object terminal, the connector terminal comprising: a housing ( 14 ) configured to slide over the object terminal ( 90 ); and a spring piece ( 34 ) connected to the housing ( 14 ), the spring piece ( 34 ) including a pressing portion ( 46 ) which is configured to be located outside of the housing ( 14 ) in a free state of the spring piece ( 34 ), and to move into the housing ( 14 ) owing to an elastic deformation of the spring piece ( 34 ) when the pressing portion ( 46 ) is pressed by the planar surface ( 92 ), and a contact portion ( 48 ) which is configured to be located inside of the housing ( 14 ) in the free state of the spring piece ( 34 ), and to move out of the housing ( 14 ) and make an electric contact with the object terminal ( 90 ) as the pressing portion ( 46 ) moves into the housing ( 14 ). 
     Because the contact portion ( 48 ) is located inside of the housing ( 14 ) in the free state of the spring piece, deformation of the spring piece ( 34 ) owing to an external force applied to the contact portion ( 48 ) can be avoided, and foreign matter is prevented from adhering to the contact portion ( 48 ). Therefore, failure in electric conduction can be avoided, and a reliable electric connection can be achieved. 
     The object terminal may comprise a board side terminal ( 90 ) formed in a printed circuit board ( 94 ) and having a conductive surface ( 92 ) serving as the planar surface. 
     Preferably, the housing ( 14 ) comprises a support portion ( 54 ) supporting a portion located between the pressing portion ( 46 ) and the contact portion ( 48 ) of the spring peace ( 34 ) as a fulcrum, the pressing portion ( 46 ) serving as an effort point, and the contact portion ( 48 ) serving as a load point. 
     Thereby, a lever having a fulcrum at a point located between the pressing portion ( 46 ) and the contact portion ( 48 ), an effort point at the pressing portion ( 46 ) and a load point at the contact portion ( 48 ) is formed so that when the pressing portion ( 46 ) is pressed, the contact portion ( 48 ) moves out of the housing ( 14 ) and comes into electric contact with the object terminal ( 90 ) under a lever action in a highly repeatable manner. 
     Preferably, in the connector terminal of the present invention, the support portion ( 54 ) comprises a sloping surface ( 58 ) rising toward the pressing portion ( 46 ) of the spring piece ( 34 ), and the spring piece ( 34 ) is pivotally supported by the housing ( 14 ) at an intermediate portion ( 50 ) of the spring piece ( 34 ) serving as a fulcrum and located between the pressing portion ( 46 ) and the contact portion ( 48 ), and slidably engaged by the sloping surface ( 58 ). 
     Thereby, as the contact portion ( 48 ) moves out of the housing ( 14 ), the contact point between the intermediate portion ( 50 ) and the sloping surface ( 58 ) moves in an outward direction from the housing ( 14 ) so that the pressure applied by the contact portion ( 48 ) onto the planar surface ( 92 ) progressively increases, and a high contact pressure can be achieved between the contact portion ( 48 ) and the planar surface ( 92 ). 
     Preferably, in the connector terminal of the present invention, the housing ( 14 ) comprises a rectangular bottom piece ( 16 ) and a pair of side vertical pieces ( 18 ,  20 ) extending along either side edge of the bottom piece ( 16 ), and the support portion comprises an opening ( 54 ) provided in each side vertical piece, and the intermediate portion of the spring piece comprises an extension ( 50 ) extending laterally from the spring piece and engaged by the opening ( 54 ). 
     Thereby, the spring piece ( 36 ) can be pivotally supported in a highly simple manner without requiring a pivot shaft or the like. 
     Preferably, in the connector terminal of the present invention, the pressing portion ( 46 ) is configured to serve as an additional contact point for electric contact with the object terminal ( 90 ) when the pressing portion ( 46 ) is pressed by the planar surface ( 92 ). 
     Thereby, the pressing portion ( 46 ), in addition to the contact portion ( 48 ), also contributes to an electric connection with the object terminal ( 60 ) so that the reliability of electric connection can be enhanced. 
     Preferably, in the connector terminal of the present invention, the housing ( 14 ) comprises a slot ( 22 ) defined by a rectangular bottom piece ( 16 ) and a pair of side vertical pieces ( 18 ,  20 ) extending along either side edge of the bottom piece ( 16 ), the contact portion ( 48 ) being configured to be received in the slot ( 22 ) in the free state of the spring piece. 
     Thereby, because the contact portion ( 48 ) is received in the slot ( 22 ) in the free state of the spring piece, the contact portion ( 48 ) is prevented from being deformed owing to an inadvertent application of an external force to the contact portion ( 48 ), and foreign matter is prevented from being deposited on the contact portion ( 48 ). 
     Preferably, in the connector terminal of the present invention, the spring piece ( 34 ) comprises a base end portion ( 36 ) fixedly attached to the housing ( 14 ), and extends from the base end portion ( 36 ) toward the pressing portion ( 46 ) in a sliding direction in relation to the object terminal ( 90 ), and is folded back so as to extend from the pressing portion ( 46 ) to the contact portion ( 48 ) in an opposite sliding direction in relation to the object terminal ( 90 ). 
     Thereby, a hairpin shaped portion ( 44 ) is produced by the spring piece ( 34 ) so that the movement of the contact portion ( 48 ) out of and into the housing ( 14 ) in response to the pressing and releasing of the pressing portion ( 46 ) can be achieved in a highly repeatable manner under the elastic deformation of the hairpin shaped portion ( 44 ). 
     Preferably, in the connector terminal of the present invention, the housing ( 14 ) and the spring piece ( 36 ) are formed as a single integral member. 
     Thereby, the number of component parts can be reduced, and the need for an assembly work can be eliminated. 
     The present invention also provides a method of manufacturing the connector terminal ( 10 ) defined above, wherein the method comprises: a blanking step of blanking a sheet material into a blank (W) having a developed flat shape containing an entirety of the connector terminal ( 10 ); and a bending step of bending the blank (W) into the connector terminal. 
     Thereby, the connector terminal ( 10 ) can be produced both efficiently and economically by performing the blanking step for obtaining the blank (W), and the bending step for bending the blank (W). 
     The present invention also provides a connector terminal ( 10 ) configured to be electrically connected to a board side terminal ( 90 ) having a conductive surface ( 92 ), the connector terminal ( 10 ) comprising: a spring piece ( 34 ) provided with a contact portion ( 48 ) configured to resiliently contact the conductive surface ( 92 ) of the board side terminal ( 90 ) when the connector terminal ( 10 ) is at a connection completion position where connection of the connector terminal ( 10 ) with the board side terminal ( 90 ) is completed; and a housing ( 14 ) configured to support the spring piece ( 34 ) and to guide a sliding movement of the connector terminal ( 10 ) along the conductive surface ( 92 ) of the board side terminal ( 90 ) toward the connection completion position, wherein the spring piece ( 34 ) further includes a pressing portion ( 46 ) that, in a free state where no external force is applied to the pressing portion ( 46 ), is positioned to intrude into a path of movement taken by the conductive surface ( 92 ) of the board side terminal ( 90 ) when the connector terminal ( 10 ) slides along the conductive surface ( 92 ) toward the connection completion position, wherein, in the free state of the pressing portion ( 46 ), the contact portion ( 48 ) is positioned such that the contact portion ( 48 ) does interfere with the path of movement of the conductive surface ( 92 ) of the board side terminal ( 90 ), and wherein the spring piece ( 34 ) is configured in such a manner that when, during the sliding movement of the connector terminal ( 10 ) relative to the board side terminal ( 90 ) toward the connection completion position, the pressing portion ( 46 ) is pressed by the conductive surface ( 92 ), the contact portion ( 48 ) is moved toward the conductive surface ( 92 ) to make a resilient contact with the conductive surface ( 92 ). 
     Because the contact portion ( 48 ) is located within the housing ( 14 ) in the free state, deformation of the spring piece ( 34 ) owing to an external force applied to the contact portion ( 48 ) can be avoided, and foreign matter is prevented from adhering to the contact portion ( 48 ). Therefore, failure in electric conduction can be avoided, and a reliable electric connection can be achieved. 
     The present invention also provides a connector terminal ( 10 ) configured to be electrically connected to a board side terminal ( 90 ) provided with a conductive surface ( 92 ) by making a sliding engagement with the conductive surface ( 92 ), the connector terminal ( 10 ) comprising: a housing ( 14 ) configured to slide over the board side terminal ( 90 ); and a spring piece ( 34 ) supported by the housing ( 14 ) and configured to resiliently contact the conductive surface ( 92 ), the spring piece ( 34 ) including a base end portion ( 36 ) fixedly attached to the housing ( 14 ), an intermediate portion ( 46 ) configured to move into a path of movement of the conductive surface ( 92 ) as the housing ( 14 ) slide over the board side terminal ( 90 ) in a free state of the spring piece ( 34 ), and a free end portion ( 48 ) configured to be positioned out of the path of movement of the conductive surface ( 92 ) as the housing ( 14 ) slide over the board side terminal ( 90 ) in the free state of the spring piece ( 34 ) where no external force is applied, the spring piece ( 34 ) being configured in such a manner that the free end portion ( 48 ) moves into the path of movement of the conductive surface ( 92 ) to serve as a contact portion ( 48 ) for electric contact with the board side terminal ( 90 ) as the intermediate portion ( 46 ) is pressed by the conductive surface ( 92 ) owing to a sliding movement of the connector terminal ( 10 ) relative to the board side terminal ( 90 ). 
     Because the free end portion ( 48 ) is located out of the path of movement of the conductive surface ( 92 ), deformation of the spring piece ( 34 ) owing to an external force applied to the contact portion ( 48 ) can be avoided, and foreign matter is prevented from adhering to the contact portion ( 48 ). Therefore, failure in electric conduction can be avoided, and a reliable electric connection can be achieved. 
     Effect of the Invention 
     According to the connector terminal of the present invention, the spring piece provided with the contact portion is prevented from being deformed during the assembly work or the like, and deposition of foreign matter on the surface of the contact portion that could cause a conduction failure is avoided so that a favorable electric conduction may be ensured in a reliable manner. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a right side view of a connector terminal according to a first embodiment of the present invention; 
         FIG. 2  is a plan view of the connector terminal of the first embodiment of the present invention; 
         FIG. 3  is a sectional view taken along line III-III of  FIG. 2 ; 
         FIG. 4  is a perspective view of the connector terminal of the first embodiment of the present invention; 
         FIG. 5  is a fragmentary sectional perspective view of the connector terminal of the first embodiment of the present invention; 
         FIG. 6  is a fragmentary sectional view of the connector terminal of the first embodiment of the present invention in an initial stage of connection; 
         FIG. 7  is a fragmentary sectional view of the connector terminal of the first embodiment of the present invention in a final stage of connection; 
         FIG. 8  is a perspective view of a waterproof, multiple pole card edge connector using the connector terminals of the first embodiment; 
         FIG. 9  is a sectional view showing an assembling process of the waterproof, multiple pole card edge connector using the connector terminals of the first embodiment; 
         FIG. 10  is a plan view of sheet metal blank used as the material for the connector terminal of the first embodiment; 
         FIG. 11  shows perspective views of various steps in a bending process of the connector terminal of the first embodiment; 
         FIG. 12  is a sectional view showing an important part of a connector terminal according to a second embodiment of the present invention; and 
         FIG. 13  is a sectional view showing an important part of a connector terminal according to a third embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S) 
     A connector terminal according to a first embodiment of the present invention will be described in the following with reference to  FIGS. 1 to 7 . In the following description, directions such as vertical, front, rear, left and right are defined as indicated in the drawings, and the surface of the connector terminal on which the mating terminal makes a sliding contact is referred to as the upper surface, but this is only for convenience of explanation, and does not limit the scope of the present invention. 
     The connector terminal  10  is designed for use in a card edge connector. As shown in  FIGS. 1, 2, and 6 , a mating connector terminal for the connector terminal  10  consists of a board side terminal  90  (card edge terminal) formed on a board surface  96  of a printed circuit board  94  (hereinafter referred to simply as the board  94 ). The board side terminal  90  has a planar conductive surface  92  which is flush with the board surface  96 . 
     The connector terminal  10  consists of a slide type terminal which is electrically connected to the board side terminal  90  by sliding in the fore and aft direction along the board surface  96  of the board  94  and the conductive surface  92  of the board side terminal  90 . 
     As shown in  FIGS. 1, 2, and 4 , the connector terminal  10  includes a cable connecting portion  12  which is electrically connected to a conductor  102  of a cable  100 , a housing  14  located on the front side of the cable connecting portion  12  to guide the sliding movement of the connector terminal  10  with respect to the board side terminal  90 , and a spring piece  34  that is supported by the housing  14  to resiliently contact the conductive surface  92  and the board surface  96 . 
     The housing  14  is provided with a rectangular bottom piece  16  elongated in the sliding direction (fore and aft direction) with respect to the conductive surface  92  of the board side terminal  90 , and a right side vertical piece  18  and a left side vertical piece  20 ,  16 B extending along the left and right side edges of the bottom piece  16 , respectively. Thereby, a slot (channel shaped portion)  22  having an upper open end is formed. The upper edge of the right side vertical piece  18  and the upper edge of the left side vertical piece  20  are connected to each other at front portions, intermediate portions and rear portions thereof by connecting pieces  24 ,  26  and  28 , respectively. The bottom piece  16 , the right side vertical piece  18 , the left side vertical piece  20 , and the connecting piece  24  are provided with front end pieces  16 A,  18 A,  20 A and  24 A bent from the respective front ends thereof toward one another so as to define a square pyramid defining a pointed tip end. 
     The upper end surfaces of the right side vertical piece  18  and the left side vertical piece  20 , and the upper surfaces of the connecting pieces  24  and  26  are flush with one another, and jointly define a slide surface  30  configured to slide over the conductive surface  92 . The connector terminal  10  is disposed with respect to the board  94  such that the slide surface  30  slides over the conductive surface  92  of the board side terminal  90  and the board surface  96  in a parallel relationship. A connector housing or the like that retains the board side terminal  90  may be provided with a slide guide (not shown in the drawings) that guides the connector terminal  10  in such a manner that the slide surface  30  does not contact the board surface  96  as the housing  14  is moved along the board side terminal  90  as shown in  FIGS. 1, 6 and 7 . 
     A part of the left side vertical piece  20  adjoining the front edge of the rear connecting piece  28  is integrally provided with a projecting piece  32  projecting upward beyond the slide surface  30 . 
     As shown in  FIGS. 3 and 5 to 7 , the spring piece  34  includes a base end portion  36  (see  FIG. 11 ) bent from the lower edge of a front end part of the left side vertical piece  20  and laid onto the bottom piece  16  so as to extend in the sliding direction for the conductive surface  92  (in the fore and aft direction), a lower piece  38  extending rearward (a first sliding direction with respect to the board side terminal  90 ) from the base end portion  36  in an obliquely upward direction, and an upper piece  42  bent forward from the rear end of the lower piece  38  via a semi-cylindrical folded-back portion  40  in such a manner that a hairpin shaped portion  44  is formed. Owing to this structure, the housing  14  and the spring piece  34  can be integrally formed by stamp forming a single piece of piece metal, without requiring a plurality of component pieces and the assembling of component pieces. 
     The folded-back portion  40  generally defines a rear end part of the spring piece  34 . An upper end part of the folded-back portion  40  is formed with a pressing portion  46  by stamp forming as an upwardly projecting track shaped projection. The free end or the front end of the upper piece  43  is also formed with contact portion  48  by stamp forming as an upwardly projecting track shaped projection. The contact portion  48  is configured to contact the corresponding board side terminal  90  (see  FIGS. 6 and 7 ). 
     An intermediate part of the upper piece  42  located between the pressing portion  46  and the contact portion  48  is provided with a lateral extension  50  extending outwardly from the side edges of the upper piece  42 . The extension  50  is formed in a semi-cylindrical shape with a convex side thereof facing downward, and is configured to serve as a pivot point or a fulcrum for the spring piece  34  relative to the housing  14 . The right side vertical piece  18  and the left side vertical piece  20  are each formed with an opening  54  (a cutout) having an open upper end. In particular, an upwardly facing surface  58  defining a lower edge of the opening  54  slopes upward toward the rear or toward the folded-back portion  40  of the spring piece  34 . The extension  50  rests upon the upwardly facing surface  58  of the opening  54  of the right side vertical piece  18  and the left side vertical piece  20  so as to be pivotable and slidable in the fore and aft direction. Thus, the openings  54  serve as a fulcrum point that supports an intermediate point of the upper piece  42  located between the contact portion  48  and the pressing portion  46 . Thus, a lever mechanism including an effort point located at the pressing portion  46  and a load point located at the contact portion  48  is formed. This lever mechanism is formed in a highly simple manner without requiring a pivot shaft or the like. In particular, the contact portion  48  is entirely received in the slot  22 , and is positioned below the slide surface  30 . 
     In a free state where the hairpin shaped portion  44  is not pressed downward, as shown in  FIGS. 2 to 6 , the pressing portion  46  is located outside the housing  14  or more importantly, positioned above the slide surface  30 . During the process of connecting the connector terminal  10  to the board side terminal  90 , the pressing portion  46  is located in the way of the conductive surface  92  as the conductive surface  92  moves along the slide surface  30  with the result that the pressing portion  46  is pressed downward under pressure from the conductive surface  92 . This causes the upper piece  42  to rotate in clockwise direction in  FIG. 7  around the extension  50  and deflect downward while the hairpin shaped portion  44  undergoes a corresponding elastic deformation. As a result, the pressing portion  46  is received into the slot  22 . 
     In the free state where the pressing portion  46  is not pressed downward, the contact portion  48  is entirely received in the slot  22  and is located below the slide surface  30  as shown in  FIGS. 2 to 6  so that the contact portion  48  does not interfere with the path of the movement of the conductive surface  92  during the process of connecting the connector terminal  10  to the board side terminal  90 . When the pressing portion  46  is pressed downward in the process of connecting the connector terminal  10  to the board side terminal  90 , as shown in  FIG. 7 , the upper piece  42  is rotated in the clockwise direction around the extension  50  which provides a fulcrum point while the hairpin shaped portion  44  is elastically deformed so that the contact portion  48  moves upward from the slot  22 , in particular to a position above the slide surface  30 . As a result, the contact portion  48  moves to a position that interferes with the path of movement of the conductive surface  92  so that the contact portion  48  resiliently comes into contact with conductive surface  92  of the board side terminal  90 , and is electrically connected to the board side terminal  90 . 
     In summary, the connector terminal  10  is provided with a spring piece  34  formed with a contact portion  48  that resiliently contacts the conductive surface  92  of the board side terminal  90  when the connector terminal  10  is in the connection completion position where the connection of the connector terminal  10  to the board side terminal  90  is completed, and a housing  14  supporting the spring piece  34  and configured to guide the sliding movement of the connector terminal  10  along the conductive surface  92  of the board side terminal  90  toward the connection completion position. The spring piece  34  is provided with a pressing portion  46  that, in a free state where no external force is applied thereto, intrudes into the path of movement of taken by the conductive surface  92  as the connector terminal  10  slides along the conductive surface  92  of the board side terminal  90  toward the connection completion position. When the pressing portion  46  is in the free state thereof, the contact portion  48  is positioned so as not to interfere with the path of movement of the conductive surface  92  of the board side terminal  90 . When the pressing portion  46  is pressed by the conductive surface  92  as the connector terminal  10  slides along the conductive surface  92  toward the connection completion position, the contact portion  48  is displaced toward the conductive surface  92  to come into a resilient contact with the conductive surface  92 . 
     Next, the mode of operation in connecting the connector terminal  10  to the board side terminal  90  will be described in the following with reference to  FIGS. 6 and 7 . 
       FIG. 6  shows a free state where the pressing portion  46  is not in contact with the board surface  96  of the board  94  or the conductive surface  92  in an initial stage of connection. In this free state, the contact portion  48  is entirely received in the slot  22 , and is located below the slide surface  30  so as not to interfere with the path of movement of the conductive surface  92 . Therefore, deformation of the contact portion  48  due to an external force can be avoided, and deposition of foreign matter on the surface of the contact portion  48  can be minimized. As a result, a faulty contact of the contact portion  48  owing to such causes can be avoided, and a connection can be achieved in a highly reliable manner. 
     As shown in  FIG. 7 , as the connector terminal  10  progressively slides forward along the board  94 , the pressing portion  46  comes into contact with the board surface  96  of the board  94  and the conductive surface  92  with the result that the pressing portion  46  is pressed downward. Thereby, the upper piece  42  rotates in the clockwise direction like a lever having a fulcrum provided by the extension  50  while the hairpin shaped portion  44  undergoes an elastic deformation with the result that the pressing portion  46  is received into the slot  22 . This rotational movement of the upper piece  42  causes the contact portion  48  to move vertically away from the slot  22  or to a position above the slide surface  30 . In other words, the contact portion  48  is brought to a position that interferes with the path of movement of the conductive surface  92 . As a result, the contact portion  48  resiliently contacts the conductive surface  92  of the board side terminal  90 , and an electric connection is established between the connector terminal  10  and the board side terminal  90 . 
     Because the contact portion  48  resiliently contacts the conductive surface  92  of the board side terminal  90  only after the pressing portion  46  is pressed downward by the board surface  96  and the conductive surface  92 , the contact portion  48  and the conductive surface  92  are brought into contact with each other over only a small part of the entire stroke of the sliding movement of the connector terminal  10  relative to the board  94  so that the wear of the contact portion  48  and the conductive surface  92  can be minimized. Also, the contact portion  48  is prevented from being abraded or otherwise damaged by the edge of the board  94 . Therefore, even after the connector is connected and disconnected by a large number of times, the terminals can continue to operate in a satisfactory manner. 
     The distance along which the contact portion  48  and the conductive surface  92  are in sliding contact with each other can be determined by appropriately selecting the timing of actuating the spring piece  34 . If a wiping effect (removal of oxide film on the connector terminal  10 ) is desired, this sliding distance can be selected in a corresponding manner. 
     Because the movement of the upper piece  42  discussed above is effected by the lever action having a fulcrum positioned at the extension  50 , the path of movement of the contact portion  48  due to the downward movement of the pressing portion  46  is uniquely determined. In other words, the movement of the contact portion  48  into the path of movement of the conductive surface  92  can be effected in a highly repeatable manner owing to the lever action. Therefore, even after the connector is connected and disconnected by a large number of time, it is still ensured that the contact portion  48  is brought into contact with the conductive surface  92  of the board side terminal  90  in a precise manner. 
     Because the upward rotational movement of the upper piece  42  around the fulcrum point provided by the extension  50  is performed under the elastic deformation of the hairpin shaped portion  44  having the fixed base end portion  36 , the contact point between the extension  50  and the upwardly facing surface  58  moves upward and rearward as the upper piece  42  rotates in clockwise direction so that the pressure of the contact portion  48  onto the conductive surface  92  increases, and the contact between the contact portion  48  and the conductive surface  92  becomes firmer during this process. In other words, the electric connection between the connector terminal  10  and the board side terminal is achieved with a high contact pressure. Furthermore, because a relatively large vertical travel of the contact portion  48  can be achieved in spite of a small lever length of the upper piece  42 , the size (length) of the connector terminal  10  can be minimized owing to the reduction in the lever length of the upper piece  42 . 
     When the contact portion  48  resiliently contacts the conductive surface  92 , the pressing portion  46  also resiliently contacts the conductive surface  92  as shown in  FIG. 7  so that the pressing portion  46  also contributes to the electric connection with the board side terminal  90 . This enhances the reliability of the electric connection. 
     When the connector terminal  10  is displaced from the board side terminal  90 , or in other words, when the board  94  is removed from the connector terminal  10 , the pressure of the board surface  96  and the conductive surface  92  on the pressing portion  46  is removed with the result that the elastic deformation of the hairpin shaped portion  44  is relieved, and the free state of the spring piece  34  is restored. As a result, the contact portion  48  entirely descends into the slot  22 , and is positioned under the slide surface  30 . Since the hairpin shaped portion  44  is configured to have a favorable resiliency, the restoring action mentioned above can be achieved in a highly repeatable manner. 
       FIG. 8  shows an example of the card edge multiple pole connector  60  including a plurality of connector terminals  10 . The card edge multiple pole connector  60  is provided with a connector housing  62  housing two rows of connector terminals in a mirror image of each other one above the other, each row containing three connector terminals. The connector terminals  10  of the lower row face upward so that the contact portions  48  are located on an upper end side of the housing  14  while the connector terminals  10  of the upper row face downward so that the contact portions  48  are located on a lower end side of the housing  14 . 
     The board  94  may, for example, be that of an electronic control unit  98 , and is provided with three board side terminals  90  as card edge terminals on the upper and lower surfaces thereof, respectively. By inserting the edge of the board  94  between the upper connector terminals  10  and the lower connector terminals  10  of the card edge multiple pole connector  60 , the upper connector terminals  10  are electrically connected to the board side terminals  90  on the upper surface of the board  94  while the lower connector terminals  10  are electrically connected to the board side terminals  90  on the lower surface of the board  94 . 
     When the card edge multiple pole connector  60  is of a waterproof specification, as shown in  FIGS. 8 and 9 , a rubber seal member  80  is fitted to the connector housing  62  of the card edge multiple pole connector  60  in an air tight manner, and cables  100  each connected to the corresponding connector terminal  10  is passed through an individual insertion hole  82  passed through the rubber seal member  80 . 
     In the assembling process, while the seal member  80  is fitted in a seal mounting opening  64  formed in the connector housing  62 , each connector terminal  10  to which the corresponding cable  100  is connected is inserted into the corresponding insertion hole  82  from the front end side of the housing  14  until the cable  100  is positioned in the insertion hole  82  as in the connector terminal  10  shown in an upper part of  FIG. 9 . 
     When passing the cable  100  through the insertion hole  82 , the housing  14  passes through the insertion hole  82  while pushing out the inner circumferential wall of the insertion hole  82 . In this case, the effective axial length La of the insertion hole  82  is smaller than the distance Lb between the pressing portion  46  and the contact portion  48  as measured in the axial direction. Therefore, in the course of passing the housing  14  through the insertion hole  82 , by the time the pressing portion  46  starts pressing upon the inner circumferential surface of the insertion hole  82 , the contact portion  48  has already passed through and exited the insertion hole  82 . The effective axial length La of the insertion hole  82  in this case is defined as the axial distance between axially outermost seal lands  84  that closely contact the cable  100  at the respective axial ends of the insertion hole  82 . 
     Owing to this arrangement, when the contact portion  48  passes through the insertion hole  82 , the spring piece  34  remains in the free state as is the case with the lower connector terminal  10  shown in  FIG. 9 . When the contact portion  48  is passing through the insertion hole  82 , the contact portion  48  is entirely received within the slot  22  and is located below the slide surface  30  so that the contact portion  48  does not make any sliding contact with the inner circumferential surface of the insertion hole  82 . 
     Thereby, any foreign matter such as a releasing agent and lubricant that may be adhering to the inner circumferential surface of the insertion hole  82  at the time of installing the seal member  80  is prevented from adhering to the surface of the contact portion  48 . In this way, the surface of the contact portion  48  is prevented from being contaminated by impurities so that occurrence of conduction failure due to contamination is avoided, and satisfactory electric connection can be ensured in a reliable manner. 
     If the elastic force of the seal member  80  is not strong enough to drive the spring piece  34 , the dimensional relationship between the effective axial length La and the distance Lb may not be required to be determined as discussed above. 
     When the pressing portion  46  passes through the insertion hole  82 , foreign matter that may have adhered to the pressing portion  46  may be transferred to the conductive surface  92 . However, the region of the conductive surface  92  to which the foreign matter is transferred is limited to the region where the pressing portion  46  makes a sliding contact with the conductive surface  92 , and does not extend to the region where the contact portion  48  makes a sliding contact with the conductive surface  92 . Therefore, occurrence of conduction failure due to contamination is avoided, and satisfactory electric connection can be ensured in a reliable manner. 
     An example of a method of manufacturing the connector terminal  10  will be described in the following with reference to  FIGS. 10 and 11 . 
     The manufacturing method of the connector terminal  10  includes a blanking step of obtaining sheet material blanks W each having a developed flat shape of the entire connector terminal  10  as shown in  FIG. 10 , and a bending step of bending the blank W along bending lines a to m so as to form the connector terminal  10  as shown in  FIG. 11 . 
     The bending step is discussed in more detail with reference to ( 1 ) to ( 7 ) in  FIG. 11 . ( 1 ) to ( 7 ) in  FIG. 11  are intended to show the bending directions, and are not necessarily required to be performed as individual steps. For instance, the bending shown in ( 3 ) may be performed simultaneously as the bending shown in ( 4 ). 
     The pressing portion  46  and the contact portion  48  are formed by embossing at predetermined parts of the blank W as shown in ( 1 ), and the spring piece  34  including the hairpin shaped portion  44  is formed by bending along lines a to d shown in ( 3 ) to achieve the state shown in ( 3 ). 
     The front end pieces  16 A,  18 A,  20 A and  24 A and the projecting piece  32  as well as the spring piece  34  are formed by bending along lines e to j shown in ( 2 ) to put them into the state shown in ( 3 ). 
     The blank W is then bent along line k shown in ( 3 ) to form the right side vertical piece  16 B as shown in ( 4 ). 
     The blank W is bent along line l shown in ( 4 ) to form the left side vertical piece  20  as shown in ( 5 ). 
     The blank W is bent along lines m shown in ( 5 ) to form the connecting pieces  24 ,  26  and  28  as shown in ( 6 ). 
     The blank W is bent along lines n shown in ( 6 ) to form the bottom piece  16  and the right side vertical piece  18 . Thereby, the base end portion  36  is laid onto the bottom piece  16 , and the connector terminal  19  is completed as shown in ( 7 ). 
     As described above, the connector terminal  10  can be manufactured without requiring an assembling step simply by bending a single blank W blanked into a developed shape including the entire connector terminal  10 . Therefore, the connector terminal  10  can be produced both efficiently and economically. 
     A connector terminal according to a second embodiment of the present invention will be described in the following with reference to  FIG. 12 . In  FIG. 12 , parts corresponding to those in  FIG. 3  are denoted with like reference numerals without necessarily repeating the description of such parts. 
     In the second embodiment, the extension  50  used in the first embodiment is omitted, and the upper piece  42  is formed as a cantilever arm that is not pivotally supported by the housing  14 . 
     In a free state where the hairpin shaped portion  44  is not pressed downward, the pressing portion  46  is located outward of the housing  14 , or in other words, above the slide surface  30  as shown in  FIG. 12 . In particular, the pressing portion  46  interferes with the path of motion of the conductive surface  92 . Therefore, when the pressing portion  46  is pressed downward, the pressing portion  46  moves downward owing to the elastic deformation of the hairpin shaped portion  44  or the lower piece  38 , and thereby moves into the slot  22 . 
     In the free state where the pressing portion  46  is not pressed downward, the contact portion  48  is entirely received in the slot  22 , and is located below the slide surface  30  as shown in  FIG. 12 . In other words, the contact portion  48  does not interfere with the path of movement of the conductive surface  92 . Once the pressing portion  46  is pressed downward, the contact portion  48  moves upward from the slot  22 , and is moved to a position located above the slide surface  30 . As a result, the contact portion  48  interferes with the path of movement of the conductive surface  92 , and resiliently comes into contact with the conductive surface  92  of the board side terminal  90 , thereby establishing an electric connection with the board side terminal  90 . 
     Thus, the second embodiment provides functions and advantages similar to those of the first embodiment. 
     A connector terminal according to a third embodiment of the present invention will be described in the following with reference to  FIG. 13 . In  FIG. 13 , parts corresponding to those in  FIG. 3  are denoted with like reference numerals without necessarily repeating the description of such parts. 
     In the third embodiment, the base end portion  36  and the lower piece  38  of the first embodiment are omitted, and the upper piece  42  is pivotally supported by the housing  14  by the extension  50 . The pressing portion  46  and the contact portion  48  serve as two abutting portions provided along the longitudinal direction of the upper piece  42 . The upper piece  42  is configured in such a manner that as the upper piece  42  slides along the board side terminal  90 , and the conductive surface  92  presses onto one of the abutting portions, the other abutting portion is caused to move into the path of movement of the conductive surface  92 . Thereby, the other abutting portion serves as the contact portion for electrically contacting the board side terminal  90 . 
     Thus, as shown in  FIG. 13 , in the initial state where the pressing portion  46  is not pressed downward, the pressing portion  46  is located outside the housing  14  or above the slide surface  30  as shown in  FIG. 13 . When the pressing portion  46  which is in the path of movement of the conductive surface  92  is pressed downward by the conductive surface  92 , the upper piece  42  undergoes a clockwise rotation around a fulcrum provided by the extension  50  so that the pressing portion  46  moves into the slot  22 . 
     In the initial state where the pressing portion  46  is not pressed downward, the contact portion  48  is entirely received within the slot  22 , and is hence located below the slide surface  30  as shown in  FIG. 13 . In other words, the contact portion  48  does not interfere with the path of movement of the conductive surface  92 . Once pressing portion  46  is pressed downward, the contact portion  48  undergoes a clockwise rotation around a fulcrum provided by the extension  50 , and moves to a position above the slot  22  or above the slide surface  30 . As a result, the contact portion  48  moves into the path of movement of the conductive surface  92  of the board side terminal  90 , and resiliently comes into contact with the conductive surface  92 , thereby establishing an electric connection with the board side terminal  90 . 
     Thus, the third embodiment provides functions and advantages similar to those of the first embodiment. In the third embodiment, a biasing means such as a spring may be provided for urging the upper piece  42  in a counter-clockwise direction. In this case, the free state of the biasing means provides the initial state. In the third embodiment, it suffices if a conductive connection is made between the spring piece  34  and the housing  4  at the pivot point between the upper piece  42  and the housing  14 . 
     Although the present invention has been described with reference to preferred embodiments thereof, it is to be understood by those skilled in the art that the present invention is not limited by such embodiments, but various modifications can be made without departing from the spirit of the present invention. For example, the positions of the housing  14  and the spring piece  34  can be interchanged so that the pressing portion  46  is in front of the contact portion  48  (in terms of the direction of inserting the connector terminal  10 ). The spring piece  34  may be bent from the front end of the bottom piece  16  or formed in other ways as long as the spring piece  34  is electrically connected to the housing  14 . 
     GLOSSARY OF TERMS 
     
         
           10  connector terminal 
           12  cable connecting part 
           14  housing 
           16  bottom piece 
           18  right side vertical piece 
           20  left side vertical piece 
           22  slot 
           24  connecting piece 
           26  connecting piece 
           28  connecting piece 
           30  sliding surface 
           32  projecting piece 
           34  spring piece 
           36  base end part 
           38  lower piece 
           40  bent portion 
           42  upper piece 
           44  hairpin shaped portion 
           46  pressing portion (intermediate portion) 
           48  contact portion (free end portion) 
           50  extension (intermediate portion) 
           54  opening (supporting portion) 
           58  upwardly facing surface (sloping surface) 
           60  card edge multiple pole connector 
           62  connector housing 
           64  seal mounting opening 
           80  seal member 
           82  insertion hole 
           90  board side terminal 
           92  conductive surface (planar surface) 
           94  printed circuit board 
           96  board surface (planar surface) 
           98  electronic control unit 
           100  cable 
           102  conductor