Patent Publication Number: US-8523619-B2

Title: Terminal fitting

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to a terminal fitting. 
     2. Description of the Related Art 
     U.S. Pat. No. 7,156,704 discloses a terminal fitting with a box-shaped main portion capable of receiving a tab of a mating terminal fitting. A resiliently deformable resilient contact piece is arranged in the main portion and can be connected to the tab inserted into the main portion. The main portion includes a base that faces the resilient contact piece in a resilient deforming direction of the resilient contact piece. The base has substantially the same thickness in a length direction except at a through hole formed in a front end portion thereof. The resilient contact piece is cantilevered obliquely up toward the front from the rear end thereof and is bent to form a substantially U-shaped support that is in contact with the upper surface of the base. The tab inserted into the main portion, contacts the resilient contact piece and causes the resilient contact piece to deform resiliently toward the base with the support as a supporting point. 
     The support and the base of the above-described terminal fitting are juxtaposed in a height direction which is the resilient deforming direction of the resilient contact piece, and the thicknesses of both portions are added to the height of the main portion. Accordingly, it is difficult to reduce the height of the main portion. On the other hand, the height of the main portion can be reduced if the height of the resilient contact piece is reduced. However, this may lead to a situation where there is an insufficient deformation space for the resilient contact piece. 
     The invention was developed in view of the above situation and an object thereof is to enable a miniaturization of a terminal fitting while ensuring a deformation space for a resilient contact piece. 
     SUMMARY OF THE INVENTION 
     The invention relates to a terminal fitting made of an electrically conductive plate material. The terminal fitting has a substantially box-shaped tubular main portion that can receive a tab of a mating terminal fitting. A resiliently deformable resilient contact is arranged in the main portion and can be connected to the tab inserted into the main portion. The resilient contact has a support that functions as a support for resilient deformation. The main portion includes a base facing the resilient contact piece in a deforming direction of the resilient contact. A recess is formed within the thickness range of the base and the support is in contact with the bottom surface of the recess. As a result, a dimension of the main portion is reduced by the depth of the recess while a deformation space for the resilient contact is ensured. Therefore, the terminal fitting can be miniaturized while maintaining a deformation space for the resilient contact. 
     The support preferably is in contact with the bottom surface of the recess while being pre-loaded. Thus, a contact state of the support and the base is maintained firmly. 
     The resilient contact piece preferably includes a straight portion extending substantially straight from a back end of the main portion to the support along the base. Thus, the resilient contact can be formed easily without needing to bend this part. 
     The resilient contact piece preferably comprises a straight portion extending substantially horizontally forward from the main portion, a support connected to the front end of the straight portion and a resilient main body extending obliquely in toward the front from the support and inclined somewhat down toward the front at its front end portion. 
     The recess preferably extends from a position substantially corresponding to an intermediate portion of the resilient main body to a position substantially corresponding to a rear end of the straight portion in forward and backward directions and in a range substantially over an entire width of a base of the main portion in the width direction. 
     The base of the main portion preferably is formed with a through hole or recess at a position substantially facing a free end of the resilient main body. 
     A retraction groove preferably is formed in an inner surface of the base and communicates with the through hole. Thus, the front end of the resilient main body can enter the retraction groove when the resilient contact piece is deformed excessively. 
     The depth of the retraction groove preferably increases gradually toward the through hole. 
     The resilient main body and the straight portion preferably are separated from the bottom surface of the recess. 
     A depth of the recess preferably is substantially equal to a projecting distance of the support. 
     The main portion preferably comprises a ceiling with a first ceiling plate connected to one side of the main portion and a second ceiling plate connected to another side of the main portion. 
     The first ceiling plate may comprise a front first ceiling plate located toward a front end and a rear first ceiling plate located toward a rear end. The second ceiling plate comprises a front second ceiling plate located toward a front end and a rear second ceiling plate located toward a rear end. The front second ceiling plate preferably is bent to project in, thereby forming a receiving portion. 
     The rear second ceiling plate preferably comprises a coupling connected to another side portion and an extending portion connected to the rear edge of a ceiling plate. The coupling preferably is arranged before the rear first ceiling plate. The coupling preferably is formed with at least one projection right before the rear first ceiling plate. 
     These and other objects, features and advantages of the invention will become more apparent upon reading the following detailed description of preferred embodiments and accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an enlarged section of an essential part showing a state where a terminal fitting according to the invention is connected to a mating terminal fitting. 
         FIG. 2  is an enlarged section of an essential part showing a state before connection to the mating terminal fitting. 
         FIG. 3  is a front view of the terminal fitting. 
         FIG. 4  is a plan view of the terminal fitting. 
         FIG. 5  is a side view of the terminal fitting. 
         FIG. 6  is a section along A-A of  FIG. 5 . 
         FIG. 7  is a development view of the terminal fitting. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A terminal fitting  10  according to the invention is identified by the numeral  10  in  FIGS. 1 to 7 . The terminal fitting  10  is formed integrally or unitarily by applying a bending, folding and/or embossing process and the like to an electrically conductive metal plate material punched or cut out into a development shape shown in  FIG. 7 . The terminal fitting  10  is connectable to a mating terminal fitting  60 . 
     As shown in  FIGS. 4 and 5 , the terminal fitting  10  includes a rectangular tubular main portion  11 , a resiliently deformable contact piece  12  arranged in the main portion  11 , and a wire connection portion  13  located behind and continuous with the main portion  11 . The wire connection portion  13  includes a wire barrel  14  to be crimped, bent or folded into connection with a core exposed at an end of an unillustrated wire and an insulation barrel  15  to be crimped, bent or folded into connection with an insulation coating near the end portion the wire. The wire barrel  14  comprises two wire barrel pieces  16  to wrap around the core from substantially opposite sides in a width direction. The wire barrel pieces  16  are arranged at the same position in forward and backward directions. The insulation barrel  15  comprises two insulation barrel pieces  17  to wrap around the insulation coating from opposite sides in the width direction. The insulation barrel pieces  17  are displaced from each other in forward and backward directions. 
     As shown in  FIG. 3 , the main portion  11  comprises a base  18 , two sides  19  projecting up from opposite widthwise sides of the base  18  and a ceiling  20  substantially facing the base  18 . The base  18  extends substantially horizontally over the entire length of the terminal fitting  10  and is shared by the wire connection portion  13 . 
     A closing portion  21  is formed at the front of the main portion  11  by bending a front end of the base  18  and a tab insertion opening  22  is formed above the closing portion  21  at the front of the main portion  11 . A tab  61  can be inserted into the main portion  11  from the front through the tab insertion opening  22  and along an inserting direction ID. Cutouts  23  are formed at the front edges of the sides  19  and at the opposite sides of the terminal insertion opening  22  in the width direction. 
     As shown in  FIG. 7 , the ceiling  20  comprises a first ceiling plate  24  connected to a first side  19 A and a second ceiling plate  25  connected to the second side  19 B. The first ceiling plate  24  comprises a front first ceiling plate  26  located toward a front end and a rear first ceiling plate  27  located toward a rear end. The second ceiling plate  25  comprises a front second ceiling plate  28  located toward a front end and a rear second ceiling plate  29  located toward a rear end. 
     As shown in  FIG. 2 , the front and rear first ceiling plates  26 ,  27  are placed respectively on the upper surfaces of the front and rear second ceiling plates  28 ,  29 . A slit  30  of a specified dimension is formed between the rear edge of the front second ceiling plate  28  and the front edge of the rear second ceiling plate  29 , as shown in  FIG. 4 . 
     The front first ceiling plate  26  is shorter than the front second ceiling plate  28  in forward and backward directions. The front edge of the front first ceiling plate  26  is located behind the front edge of the front second ceiling plate  28 , and the rear edge of the front first ceiling plate  26  is located before the rear edge of the front second ceiling plate  28 . 
     The front first ceiling plate  26  is hammered or embossed up and out to form a locking projection  31 . The locking projection  31  is inclined up and out toward the back from the front to the rear of the front first ceiling plate  26 . The rear of the locking projection  31  defines a locking edge  32 . A locking lance formed at an inner wall of a cavity of an unillustrated connector housing resiliently engages the locking edge  32  of the locking projection  31  when the terminal fitting  10  is inserted into the cavity, thereby retaining the terminal fitting  10  in the cavity. 
     The front second ceiling plate  28  is hammered, embossed or bent to project down and in to form a receiving portion  49  at a front end of the front second ceiling plate  28 . The receiving portion  49  extends substantially horizontally along the inserting direction ID from this bent position to the rear edge of the front second ceiling plate  28 . A recess  33  is formed on the upper surface of the front second ceiling plate  28  at a position substantially corresponding to the receiving portion  49 . A front end portion of the locking projection  31  is to be inserted into this recess  33 . 
     The rear first ceiling plate  27  is arranged at a rear end portion of the ceiling  20 . The upper surface of the rear first ceiling plate  27  is at substantially the same height position as the upper surface of the front second ceiling plate  28 . 
     The rear second ceiling plate  29  comprises a coupling  34  connected to the upper end of the second side  19 B and an extending portion  35  connected to the rear edge of the coupling  34 . The coupling  34  is arranged before the rear first ceiling plate  27 . The rear edge of the coupling  34  and the front edge of the rear first ceiling plate  27  are in contact with each other. A projection  41  is formed by cutting and bending the coupling  34  at a position right before the rear first ceiling plate  27 . The projection  41  is arranged to substantially face the locking projection  31 . An insertion space for the locking lance is defined between the projection  41  and the locking projection  31 . 
     The extending portion  35  comprises a backward extending portion  36  that extends back from the rear edge of the coupling  34  substantially along the lower surface of the rear second ceiling plate  29 . A vertically or outward extending portion  37  is connected at a substantially right angle to hang down from the rear end of the backward extending portion  36 , and the resilient contact piece  12  extends forward at a substantially right angle from the lower end of the vertical extending portion  37 . The backward extending portion  36  is at the same height as the coupling  34  and the receiving portion  49 . The vertical or outward extending portion  37  has a window hole  38 . As shown in  FIG. 3 , parts of the vertical or outward extending portion  37  located at opposite sides of the window hole  38  in the width direction can be confirmed visually through the tab insertion opening  22  from front. 
     The resilient contact piece  12  is arranged along the base  18  in the main portion  11 . More specifically, the resilient contact piece  12  comprises a straight portion  39  extending substantially horizontally forward from the lower end of the vertical extending portion  37 , a support  40  at the front end of the straight portion  39  and a resilient main body  42  extending obliquely up and in (or intersecting the inserting direction ID) toward the front from the support  40  and then is inclined somewhat down toward the front at its front end. The resilient main body  42  is resiliently deformable vertically in a height direction with the support  40  as a supporting point. 
     A contact  43  is formed near the front end of the resilient main body  42 . The contact  43  is at a highest or most projecting position in the resilient main body  42 . A gap between the contact  43  and the receiving portion  49  is smaller than the thickness of the tab  61  when the resilient contact  12  is in a natural state. Thus, the tab  61  that has been inserted properly into the main portion  11  is sandwiched resiliently between the contact  43  and the receiving portion  49 . 
     The support  40  is bent in a substantially downwardly convex U-shape between the front end of the straight portion  39  and the rear end of the resilient main body  42 . In other words, the support  40  is bent slightly outward from the front end of the straight portion  39 . The support  40  is formed over the entire width of the resilient contact piece  12 . The entire straight portion  39  including its part connected to the support  40  is arranged substantially horizontally. 
     The base portion  18  of the main portion  11  has a through hole or recess  44  at a position substantially facing the free front end of the resilient main body  42 . When the resilient contact piece  12  is deformed resiliently down due to contact with the tab  61 , the front end of the resilient main body  42  enters the through hole or recess  44 . 
     A retraction groove  45  is formed in the upper surface of the base  18  adjacent the through hole  44  and has a gradually increasing depth toward the through hole  44 . The front end portion of the resilient main body  42  can enter the retraction groove  45  when the resilient contact piece  12  is deformed excessively. 
     A recess  46  is formed on the upper surface of the base  18  at a position facing the support  40 . The recess  46  is formed within the thickness range of the base  18 . More specifically, the recess  46  is rectangular in plan view and is formed in a range from a position substantially corresponding to an intermediate position behind the contact  43  of the resilient main body  42  to a position substantially corresponding to a rear end of the straight portion  39  in forward and backward directions and in a range over substantially over the entire width of the base  18  in the width direction, excluding chamfers  47  (see  FIG. 6 ) at both sides  19 . 
     The depth of the recess  46  is substantially equal to a projecting distance of the support  40 . The support  40  is constantly in contact with the bottom surface of the recess  46  while being pre-loaded or biased. In this case, the support  40  is substantially in line contact with the bottom surface of the recess  46  along the width direction. 
     The resilient main body  42  and the straight portion  39  are separated from the bottom surface of the recess  46 . The lower surface of the straight portion  39  and the bottom surface of the recess  46  are substantially parallel to each other. The straight portion  39  is in contact with the base  18  only at the rear end thereof. Further, the base  18  of the main portion  11  has a substantially constant thickness in forward and backward directions except at the recess  46 , the through hole  44  and the retraction groove  45 . 
     The tab  61  is inserted along the inserting direction through the tab insertion opening  22  and into the main portion  11  as shown in  FIG. 2 . Thus, the tab  61  contacts the resilient contact piece  12  and deforms the resilient contact piece  12  out and down about the support  40  and in a deforming direction DD that intersects the inserting direction ID. The front end of the resilient main body  42  escapes into the through hole  44  when the tab  61  is inserted properly into the main portion  11 , as shown in  FIG. 1 , thereby avoiding interference between the resilient contact piece  12  and the base  18 . Further, a part of the resilient main body  42  near the support  40  slightly enters the recess  46  as the resilient main body  42  inclines. Thus, the two terminal fittings  10 ,  60  are connected electrically by resiliently sandwiching the tab  61  between the contact  43  and the receiving portion  49 . 
     The recess  46  is formed on the upper or inner surface of the base  18  and the support  40  is in contact with the bottom surface of the recess  46 . Thus, the height of the contact  43  from the upper surface of the base  18  can be lowered by the depth of the recess  46  as compared with the case where the recess  46  is not present on the upper surface of the base  18 . Thus, the height of the main portion  11  can be smaller than the conventional main portion. As a result, miniaturization of the terminal fitting  10  can be realized while a deformation space for the resilient contact piece  12  is ensured. 
     Further, the support  40  is in contact with the bottom surface of the recess  46  while being pre-loaded. Thus, a contact state of the support  40  and the base  18  is firmly maintained. 
     Furthermore, the resilient contact piece  12  includes the straight portion  39  extending substantially straight from the rear end of the main portion  11  to the support  40  along the base  18 . Thus, the straight portion  39  can be formed easily without bending this part. The straight portion  39  can be formed since the support  40  is accommodated in the recess  46  and not bent in a direction to be separated upward from the base  18  unlike the conventional supporting portion. 
     The invention is not limited to the above described and illustrated embodiment. For example, the following embodiments also are included in the scope of the invention. 
     The resilient contact piece may come into contact with the base portion to prevent an excessive resilient deformation thereof. 
     The formation range and shape of the recess are not limited to those of the illustrated embodiment. 
     A locking hole may penetrate the ceiling for receiving the locking lance.