Terminal fitting and a connector

A connector (10) has a housing (12) with insertion holes (15) and terminal fittings (20) to be pressed into the insertion holes (15). Each terminal fitting (20) has a press-in portion (23) to be pressed into the insertion hole (15) while pushing material of the housing (12) outward. An accommodating portion (24) is continuous with the press-in portion (23) and has slanted surfaces (24A) narrowing the press-in portion (23) toward the rear side with respect to the inserting direction. Thus, material pushed out by the press-in portion (23) returns after the passage of the press-in portion (23) and engages the accommodat9ing portion (24). The width between the rear ends of the slanted surfaces (24A) of the accommodating portion (24) is equal to or smaller than the width of the insertion hole (15).

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a terminal fitting, to a connector provided therewith and to a method of assembling such connector.

2. Description of the Related Art

Japanese Utility Model Publication No. S61-60486 andFIG. 8herein disclose a known connector that can be mounted on a printed circuit board. With reference toFIG. 8, the connector has a housing1made of a synthetic resin. The housing1has opposite front and rear ends, and a receptacle is formed at the front end for receiving a mating connector. Through holes extend through the housing1from the receptacle to the rear end of the housing1. Terminal fittings2extend through the through holes so that front ends of the terminal fittings2extend into the receptacle. Rear ends of the terminal fittings2project from the rear of the housing1and towards the circuit board.

The terminal fittings2have press-in portions that are larger than the through holes. The press-in portions typically were used to press the terminal fittings2from the front and through the through holes of the housing1.

Terminal fittings2recently have been pressed forward from the rear of the housing1to simplify production processes and to use the same automated facilities for several different connectors. However, terminal fittings pressed from the rear of the housing, may not exhibit a sufficient terminal holding force during connection of the male and female housings against a pressure acting in the withdrawing direction of the terminal fittings.

A larger press-in portion has been considered to increase the terminal forcing force. However, the larger press-in force leads to a larger compressive stress on the housing, and might cause a crack in the housing.

The present invention was developed in view of the above problem and an object thereof is to prevent the withdrawal of terminal fittings.

SUMMARY OF THE INVENTION

The invention relates to a terminal fitting to be pressed into an insertion hole of a housing of a connector. The terminal fitting includes an inserting portion with a press-in portion to be pressed into the insertion hole. The press-in portion is dimensioned to generate outward deformation of material defining the insertion hole. The inserting portion also has an accommodating portion substantially continuous with the press-in portion. The accommodating portion has at least one slanted surface that narrows the press-in portion toward its rear side with respect to an inserting direction. Thus, the material deformed by the press-in portion can at least partly return after the press-in portion has passed to engage the accommodating portion. Thus, the returned material engages the accommodating portion to prevent the withdrawal of the terminal fitting even if a pressure acts on the terminal fitting in withdrawing direction.

The width of each terminal fitting at the rear end of the accommodating portion preferably is equal to or smaller than the width of the insertion hole.

The slanted surface of the accommodating portion preferably extends substantially up to the entrance of the insertion hole. A slanted surface that terminated at an intermediate position of the insertion hole would be steeper and a larger clearance would exist between the returned material and the slanted surface. Thus, the returned material would not catch the accommodating portion sufficiently to resist pressure on the terminal fitting in the withdrawing direction. However, the slanted surface of the accommodating portion preferably extends substantially up to the entrance of the insertion hole, and is sloped moderately. Therefore, the accommodating portion is caught sufficiently by the returned material to prevent the withdrawal of the terminal fitting when a pressure acts on the terminal fitting in withdrawing direction.

The terminal fitting may have two slanted surfaces that narrow the press-in portion toward its rear side with respect to inserting direction.

The terminal fitting preferably has a bulge for contacting a stepping surface of the housing to restrict insertion of the terminal fitting to a proper depth in the insertion hole. The bulge preferably is formed with at least one biting projection for biting in the stepping surface to deform the material near the accommodating portion towards the accommodating portion.

The invention also relates to a connector with a housing and at least one insertion hole that penetrates the housing. The above-described terminal fittings is pressed into the insertion hole from an insertion side of the housing.

The housing preferably comprises a receptacle for receiving a mating connector, and the insertion hole penetrates a back wall of the housing.

Preferably, the slanted surface of each accommodating portion extends up the entrance of the insertion hole.

The housing preferably has a stepping surface for extending the entrance of each insertion hole.

These and other features of the invention will become more apparent upon reading of the following detailed description of preferred embodiments. It should be understood that even though embodiments are separately described, single features thereof may be combined to additional embodiments.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A connector in accordance with the invention is identified by the numeral10inFIGS. 1 to 7. The connector10is configured for mounting on a printed circuit board (not shown) or some other electric or electronic device. In the following description, an end of the connector10that mates with an unillustrated mating connector (left side inFIG. 1) is referred to as the front and reference is made toFIG. 1concerning the vertical direction. The terms upper and lower are used herein as a convenient frame of reference, but are not intended to imply are required gravitational orientation.

The connector10includes a housing12that is formed unitarily from a synthetic resin, as shown inFIGS. 1 and 2. The housing12has opposite front and rear ends and a receptacle11extends into the front end.

A back wall13is formed at the rear of the receptacle11, and insertion holes15penetrate the back wall13at upper and lower stages. The insertion holes15extend along forward and backward directions FBD.

Each insertion hole15has a substantially rectangular cross section with four substantially planar surfaces aligned parallel with the center axis of the respective insertion hole15. However, each insertion hole15has a tapered front portion15A of reduced cross section. A substantially rectangular recess16is formed at the front exit end of the insertion hole15and is cross-sectionally larger than the insertion hole15. The recess16collects resin shavings or particles produced by abrasion or scratching as the terminal fitting20is pressed into the insertion hole15, thereby preventing the shavings from coming out. A substantially rectangular introducing hole18is formed at the rear end of the insertion hole15and has a larger cross sectional area than the insertion hole15.

Three out of the four surfaces of each introducing hole18excluding the upper surface are slanted to widen the introducing hole18towards the back. The upper surface of the introducing hole18extends back substantially parallel to the forward and backward directions FBD.

Stepping surfaces17extend out from the rear end 15RE of the insertion hole15to the surfaces of the introducing hole18. The stepping surfaces17extend at substantially right angles to the forward and backward directions FBD.

Forcible connection preventing tabs19project forward from the back wall13substantially in correspondence with each pair of adjacent insertion holes15and between the insertion holes15at the upper stage and those at the lower stage. The forcible connection preventing tabs19guide the connection the connector10with a mating connector (not shown) so that both housings are connected at a substantially proper positional relationship.

The connector10also includes terminal fittings20, each of which is made of a conductive metallic bar material. A terminal connecting portion20B is formed at the front of each terminal fitting20and is configured for connection with a terminal fitting (not shown) of the mating connector. A board connecting portion20C is formed at the rear of each terminal fitting20and is configured for connection with the circuit board, as shown inFIGS. 3 to 7, or with a wire (not shown). The board connecting portion20C is bent down at an angle, preferably substantially by 90°, as shown inFIG. 1, when the terminal fitting20is in mounted in the housing13.

An inserting portion21is formed at intermediate part of each terminal fitting20and is configured to be inserted into the insertion hole15substantially in the inserting direction ID. A bulge22is formed behind the inserting portion21and is configured to be accommodated in the introducing hole18.

The inserting portion21is slightly shorter than the insertion hole15of the housing12. A press-in portion23is formed at substantially a front half of the inserting portion21and is defined by two slanted surfaces23A that diverge towards the back. An accommodating portion24is formed at a substantially rear half of the inserting portion21. The accommodating portion24is continuous with the press-in portion23and is defined by two slanted surfaces24A that converge moderately towards the back.

FIGS. 6 and 7show the terminal fitting20that has been pressed into the housing12. As shown inFIG. 6, the terminal fitting20has a portion20A of substantially constant rectangular cross section that extends from the front end of the terminal fitting20to a position25A slightly behind the recess16. The inserting portion21extends rearward from the position25A and becomes gradually wider towards the back due to the diverging slanted surfaces23A. The inserting portion21reaches a maximum width slightly larger than the width of the insertion hole15near a center25B of the inserting portion21and the rear of the press-in portion23. The inserting portion21then becomes gradually narrower due to the converging slanted surfaces24A of the accommodating portion24. The accommodating portion24is slightly narrower than the insertion hole15at a portion25C at the front end of the bulge22and near the stepping surfaces17. The inclination of the slanted surfaces24A preferably is more moderate than the inclination of the slanted surfaces23A.

Movement of the terminal fitting20into the insertion hole15causes a part of the press-in portion23that is wider than the insertion hole15to push material defining the insertion hole15outward. At least part of the pushed-out material then returns towards the accommodating portion24to be accommodated around the accommodating portion24.

The bulge22is substantially continuous with the rear end of the inserting portion21. Additionally, biting projections26project forward at opposite widthwise sides of the front end of the bulge22and are joined to the accommodating portion24by arcuate recesses. The bulge22contacts the stepping surfaces17of the housing12to restrict the insertion position of the terminal fitting20when the terminal fitting20is pressed to a substantially proper insertion depth. The biting projections26at the front end of the bulge22then bite into the stepping surfaces17deform the material near the accommodating portion24towards the accommodating portion24. The bulge22is accommodated in the introducing hole18so that a rear end surface22B of the bulge22is substantially flush with the rear end surface of the back wall13when the terminal fitting20is pressed to the proper position. A portion20A of substantially rectangular cross section of constant size continues behind the bulge22towards the board connecting portion20C.

The terminal connecting portion20B of each terminal fitting20is inserted in the insertion direction ID into the entrance of the insertion hole15formed in the back wall13of the receptacle11from the rear side of the housing12, as shown by an arrow inFIG. 5.

The rear part of the press-in portion23contacts opposite sides of the entrance of the insertion hole15as the terminal fitting20is inserted further into the insertion hole15and pushes the resin material of the housing12transversely out to widen the insertion hole15. The accommodating portion24then enters the insertion hole15as the terminal fitting20is advanced further. The accommodating portion24converges gradually due to the slanted surfaces24A at the opposite widthwise sides. Thus, the material pushed out by the press-in portion23returns after the passage of the press-in portion23to engage around the accommodating portion24. The bulge22behind the accommodating portion24contacts the stepping surfaces17when the terminal fitting20reaches the proper insertion depth to prevent further insertion. As a result, the terminal fitting20is fixed at the proper insertion depth and the biting projections26bite into the stepping surfaces17to deform a part of the material near the accommodating portion24towards the accommodating portion24.

Ends of the terminal fittings20that project back beyond the rear of the back wall13are bent down preferably at substantially right angles by a bending jig (not shown) after the terminal fittings20reach their proper positions. The bent rear portions then are introduced through an alignment plate31to achieve a specified pattern and are connected with the circuit board.

Pressure acts on the terminal fittings20in withdrawing direction when the connector10is connected with a mating connector (not shown). However, the material pushed out by the press-in portions23returns after passage of the press-in portions23to engage around the accommodating portions24. This engagement of the returned material with the accommodating portions24prevents the withdrawal of the terminal fittings20. The pushed-out material would not return sufficiently if the width of the inserting portions21at the portions25C near the stepping surfaces17was larger than the width of the insertion holes15. However, the accommodating portions24at the front ends of the bulges22are narrower than the insertion holes15. Thus, the pushed-out material can return sufficiently.

Slanted surfaces24A of the accommodating portion24would have a steeper inclination if the slanted surfaces24A terminated at an intermediate position along the insertion hole15. This hypothetical design would cause larger clearances between the returned material and the slanted surfaces24A. As a result, this hypothetical accommodating portion24would not be caught sufficiently by the material, and would be less effective at resisting pressure on the terminal fitting20in withdrawing direction. However, the slanted surfaces24A of the accommodating portion24extend substantially to the entrance of the insertion hole15, and are sloped more moderately. Therefore, the accommodating portion24is caught sufficiently by the material to prevent the withdrawal of the terminal fitting20when a pressure acts on the terminal fitting20in withdrawing direction.

Further, the bulge22is formed with the biting projections26for engaging the stepping surfaces17and deforming the material towards the accommodating portion24. Thus, the accommodating portion24can be caught more securely by the shifted material to prevent the backward withdrawal of the terminal fitting20when a pressure acts on the terminal fitting20in withdrawing direction.

The invention is not limited to the above described and illustrated embodiment, and the following embodiments also are embraced by the scope of the invention as defined by the claims. Various other changes can be made without departing from the scope of the invention as defined by the claims.

Although the connector10is a circuit board connector in the foregoing embodiment, the invention may be applied to other connectors such as wire to wire connectors, wire to junction box connectors, etc.

Although the rear end of the accommodating portion24of the terminal fitting20is narrower than the insertion hole15in the foregoing embodiment, it may be substantially the same width as the insertion hole15.

The bulge22of the terminal fitting20has the biting projections26for pulling the material towards the accommodating portion24. However, the terminal fitting20may have no biting projection26or several biting projections26circumferentially and/or longitudinally spaced.

The slanted surfaces24A of the accommodating portion24converge towards the back and extend to the entrance of the insertion hole15in the foregoing embodiment. However, the slanted surfaces21A may not extend to the entrance of the insertion hole15even though the illustrated embodiment shifts the material towards the accommodating portion24more effectively.

The terminal fittings20are inserted while being aligned at the upper and lower stages in the back wall13in the foregoing embodiment. However, the terminal fittings20may be at three or more stages in the back wall13or may be arranged at a different specified pattern.

Although the cross section of the insertion holes15in the back wall13is rectangular in the foregoing embodiment, they may have a circular, elliptical, polygonal or other shape according to the invention.