Abstract:
A blade type terminal fitting ( 7 ) has blades ( 14 A,  14 B) which cut through wire insulation ( 16 ) to contact a wire core ( 17 ). To prevent widening of the blades ( 14 A,  14 B) as the wire is pressed in, a jig ( 18 ) includes pressing members ( 20 ) to prevent outward movement of the blades ( 14 A,  14 B). A more secure electrical connection is obtained.

Description:
TECHNICAL FIELD 
     The present invention relates to an electrical connector, and to a pressure contact method for attaching an electric wire thereto. 
     BACKGROUND TO THE INVENTION 
     FIGS. 5 and 6 of this specification show a connector which permits the electrical connection of a terminal fitting  41  and an electric wire  42 . The electric wire  42  is inserted from above by means of a jig  44  into the terminal fitting  41  which is installed within a connector housing  40 . The terminal fitting  41  employed in this type of connector has pressure contact blades  43  facing inwards from both sides of the central portion, the insulated electric wire  42  being pressed onto the blades  43  from above. When this pressing-in occurs, the core of the electric wire  42  and a portion of the pressure contact blades  43  come into contact since the blades  43  cut into the insulated covering. 
     However, when the electric wire  42  is pressed into the terminal fitting  41  from above, the pressure contact blades  43  are pushed in an outward direction (the directions shown by F in the diagram). As a result the pressure contact blades  43  change shape so as to widen, preventing an effective pressure contact state from being achieved. 
     The present invention has been developed after taking the above problem into consideration, and aims to provide a connector and a pressure contact method for attaching an electric wire to a terminal fitting in which the widening of the terminal fitting is controlled at the time when the electric wire is pressed in. 
     SUMMARY OF THE INVENTION 
     According to the invention there is provided an electrical connector comprising a housing having a cavity therein, and an electrical terminal within said cavity, the terminal having blade members defining a slot to receive an electrical wire by pressure contact wherein said terminal is adapted for direct engagement with an assembly jig in the vicinity of said blade members whereby as said jig pushes a wire into said slot, said blade members are held against mutual outward movement tending to widen said slot. 
     Such a connector has the advantage that the wire receiving slot is not widened on entry of the wire. Accordingly, the electrical connection is improved, and the terminal may be made of a thinner metal gauge. 
     Preferably the blade members protrude from the housing so as to permit direct engagement with an assembly jig. The side walls of a connector housing may be cut away to facilitate this protrusion. 
     In a preferred embodiment, the assembly jig includes depending limbs to both engage the blade members, and to push a wire into the slot. Where multiple terminals are provided, one limb may support blade members of adjacent terminals. These support limbs are preferably spring loaded and having a form locking engagement with the connector housing. 
     The invention also provides a method of inserting a wire into a slot of a blade connector, the method comprising the steps of placing a wire over the slot, engaging the terminal in the vicinity of the blade members so as to prevent widening of the slot and pushing a wire into said slot. 
    
    
     BRIEF DESCRIPTION OF DRAWINGS 
     Other features of the invention will be apparent from the following description of a preferred embodiment shown by way of example in the accompanying drawings in which: 
     FIG. 1 is a diagonal view of a present embodiment showing a terminal fitting fitted to a connector housing. 
     FIG. 2 is a cross-sectional view through a pressure contact mould. 
     FIG. 3 is a partial cross-sectional view of the terminal fitting before an electric wire is pressed in. 
     FIG. 4 is a partial cross-sectional view of the terminal fitting after the electric wire is pressed in. 
     FIG. 5 is a partial cross-sectional view of a prior art example showing a terminal fitting before an electric wire is pressed in. 
     FIG. 6 is a partial cross-sectional view of the prior art example showing the terminal fitting after the electric wire is pressed in. 
    
    
     DESCRIPTION OF PREFERRED EMBODIMENT 
     An embodiment of the present invention is explained with the aid of FIGS. 1 to  4 . A connector  1  shown in FIG. 1 comprises a connector housing  2 , a terminal fitting  7  and a cover (not shown) which is attached to the connector housing  2  from above. 
     The female connector housing  2  is formed in a unified manner from synthetic resin in a schematically rectangular parallelepiped shape. The female terminal fitting  7  is attached to the female connector housing  2  which fits with a male connector housing (not shown). That is, the connector housing  2  is formed in such a way that the anterior portion is larger than the posterior portion, and that it has a hood member  6  which can be fitted with the corresponding male connector housing. The posterior end is open from above and its interior is divided into three cavities  5  by walls  9 . Each cavity  5  houses a terminal fitting  7 . The anterior ends of these terminal fittings  7  are not shown, but they are inserted into the hood member  6  as far as the anterior end thereof so as to be able to make contact with the terminal fittings housed within a corresponding connector housing. Cut-out portions  8  are formed on that section of the walls  9  where pressure contact blades  14 A and  14 B (to be described later) of the terminal fitting  7  are located, a portion of a pressure contact member  14  protruding beyond the cut-away walls  9 . Further, the posterior ends of the walls  9  have relatively wide jig grooves  10  formed at the location of a barrel member  13  of the terminal fitting  7 . When the terminal fitting  7  (to be explained below) is fixed into the cavity  5 , the jig groove  10  is the only portion where a space occurs between the terminal fitting  7  and the cavity  5 . 
     As described above, when the terminal fitting  7  is housed within the connector housing  2 , the connector housing  2  can be fitted with a removable cover to close off each cavity  5 . 
     The terminal fitting  7  is formed from an electrically conductive metal plate which is bent by means of a press process. The anterior portion of the terminal fitting  7  has a contact member (not shown) which makes contact with a corresponding terminal fitting (also not shown), and the posterior portion has a barrel member  13  for making pressure contact with a wire  15 . The barrel member  13  comprises a pair of left and right protrusions mutually displaced in the anterior-posterior direction, the upper edge of these protrusions being bent slight toward the interior. After the terminal fitting  7  has been placed in the cavity  5 , when an electric wire (not shown) is to be crimped within the barrel member  13 , a crimping device (not shown) known as a crimper is inserted from above between the jig groove  10  and the barrel member  13 , the bending of the aforementioned left and right protrusions facilitating this insertion. 
     The central portion of the terminal fitting  7  is provided with a pressure contact member  14  which serves to effect pressure contact between the terminal fitting  7  and the electric wire  15 . This pressure contact member  14  has a pair of left and right pressure contact blades  14 A and  14 B in the anterior-posterior direction on both sides of the terminal fitting  7 . These pressure contact blades  14 A and  14 B are formed by being cut out from both side faces of the pressure contact member  14 . Further, the pressure contact blades  14 A and  14 B form a pair separated by a specified distance and face one another, the facing edges having sharp blades and forming a slot  4 . When the electric wire  15  presses down on the slot  4 , the blades cut into the insulation  16  as far as the core wire  17 , thus bringing the core wire  17  into contact with the pressure contact blades  14 A and  14 B (see FIGS.  3  and  4 ). 
     In order to press in the electric wire  15  from above, the present embodiment employs a pressure contact mould  18  (see FIG. 2) which can be raised and lowered. The pressure contact mould  18  has three horizontal columns formed in a parallel manner so as to correspond to the cavities  5 . This allows the pressure contact operation to be performed simultaneously on the electric wires  15  with respect to each terminal fitting  7 . Three pressing protrusions  19  are formed on the lower face of the pressure contact mould  18  which push the electric wire  15  in the direction of the terminal fitting  7 . Each pressing protrusion  19  is formed so as to be slightly longer than at least the space in the anterior-posterior direction between the pressure contact blades  14 A and  14 B of the terminal fitting  7 . When the pressure contact mould  18  is lowered, the pressing protrusions  19  press the electric wire  15  into the corresponding slots  4  of the terminal fitting  7 . Moreover, the pressing protrusions  19  have a cut-away portion  23  in that position where the pressing protrusions  19  would otherwise make contact against the pressure contact blades  14 A and  14 B as a result of the pressure contact mould  18  being lowered. Consequently, at the time of the pressing operation, an impact is avoided between the pressing protrusions  19  and the pressure contact blades  14 A and  14 B, and the pressing protrusions  19  can push the electric wire  15  deeply into the pressure contact blades  14 A and  14 B. 
     On the lower face of the pressure contact mould  18  and on both sides of each pressing protrusion  19  are a pair of pressing members  20  which constitute a widening prevention member of the present invention, and which protrude further downwards than the pressing protrusions  19 . These pressing members  20  are formed separately from the pressing protrusions  19  and are attached to the lower side of springs  21  located within groove members  22  of the main body of the pressure contact mould  18 , the springs  21  pushing the pressing members  20  downwards. These pressing members  20  are attached in such a way that they can be pressed into the groove members  22 . The pressing members  20  are provided directly above the cut-out portions  8  formed on the corresponding cut-away walls  9 . When the electric wires  15  are pushed downwards by the pressing protrusions  19 , the pressing members  20  come into contact with the outer sides of both side faces of the pressure contact member  14  of the terminal fitting  7 , and the lower edges of the pressing members  20  on the lower side of the pressure contact mould  18  make contact with the upper edges of the cut-away walls  9 . In this manner, the pressing members  20  surround both side faces of the pressure contact member  14  from the outside and thereby control the widening of the side faces of the pressure contact member  14 . 
     When the pressure contact mould  18  is pushed onto the terminal fitting  7 , the pair of pressing members  20  first surround the side faces of the pressure contact member  14  of the terminal fitting  7 . Next, since the pressing members  20  make contact with the cut-away wall  9 , they are pushed in the direction of the groove member  22 . Finally, the pressing protrusion  19  pushes the electric wire  15  in the direction of the pressure contact member  14 . At this juncture, the widening of the terminal fittings  7  is controlled because the pressing members  20  are holding the side walls of the pressure contact member  14  in a fixed position. After the pressing operation of the electric wires  15  is completed, the pressure contact mould  18  is raised and the return of the pressing members  20  to their original position is effected by the springs  21 . 
     The operation and effects of the present embodiment configured in the manner described above are explained. First, before the cover (not shown) is attached to this connector housing  2 , the terminal fitting  7  is fitted within the cavity  5  of the connector housing  2  (FIG.  3 ). After this, the electric wire  15  is positioned in a specified position on top of the terminal fitting  7  and a pressure contact mould  18  is lowered. Next, pressing members  20  surround and fix both side walls of a pressure contact member  14  from the outside. The lower edges of the pressing members  20  make contact with the upper edges of the cut-away walls  9  and the pressing members  20  are pushed into the groove members  22 . Meanwhile, the pressing protrusion  19  pushes the electric wire  15  into the slot  4  of the pressure contact blades  14 A. Then, the pressure contact blades  14 A cut into the covering  16  of the electric wire  15  and the core wire  17  comes into contact with the pressure contact blades  14 A, thus making an electrical connection between the terminal fitting  7  and the electric wire  15 . Subsequently, the barrel member  13  is crimped with respect to the covering  16  of the electric wire  15 , completing the connection of the electric wire  15  and the terminal fitting  7 . 
     In this manner, the connector  1  is completed by attaching a cover (not shown) to the connector housing  2  from above. 
     In the present embodiment, the pressure contact mould  18  is employed to press the electric wire  15  into the slot  4  of the terminal fitting  7  which is attached within the cavity  5  of the connector housing  2 . Here, the pressing-in operation of the electric wire  15  is performed after the pressing members  20  provided on the pressure contact mould  18  join with the cut-out portions  8  outside the side faces of the pressure contact member  14 . As a result, the terminal fitting  7  does not widen when the electric wire  15  is pressed in. Consequently, an effective pressing connecting force can be maintained between the core wire  17  and the terminal fitting  7 . 
     Further, since the pressing members  20  join with the external sides of the pressure contact member  14  at the time of the pressing-in operation of the electric wire  15 , the electric wire  15  can be pressed in and the widening of the terminal fitting  7  can be controlled all in a single operation. 
     The present invention is not limited to the embodiments described above. For example, the possibilities described below also lie within the technical range of the present invention. 
     (1) In the present embodiment, when the electric wire is pressed into the terminal fitting attached within the connector housing, widening is controlled by pressing both side faces of the pressure contact member located in each terminal fitting. In the case where the terminal fittings are provided entirely in a terminal housing chamber located within a connector housing, it may equally be arranged that the connector housing is pressed-in from both side faces. 
     (2) If the cover which is attached to the connector housing also serves as the lower face member of another connector housing as well as a cover, the connector housings can be placed one above the other. In this manner, a plurality of terminal fittings can be joined in a lengthwise direction. In this way a connector can be formed in a simple manner and space can easily be saved. 
     (3) The pressure contact operation between the terminal fitting and the electric wire need not be carried out only within a housing. It may equally be carried out with an individual terminal fitting.