Female terminal fitting and a method of forming it

Abstract

A female terminal fitting (1) has a rectangular tubular connecting portion (5) for connection with a male tab (4). First and second contacts (9C, 18) are provided respectively on first and second opposed walls (23, 17) of the connecting portion (5). The contacts (9C, 18) resiliently contact and hold the male tab (4). The first contact (9C) is provided at the leading end of a resilient contact piece (9). An engaging edge (25) projects from one side of a base (9A) of the resilient contact piece (9) and is fit into a locking hole (26) formed in a sidewall (15) to position the base (9A) of the resilient contact piece (9) and prevent it from being raised.

Description

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a female terminal fitting and to a method of forming or producing it.

[0003] 2. Description of the Related Art

[0004] A female terminal fitting is disclosed in International Publication No. WO 98/29924 and also is identified by the numeral 100 in FIG. 11 herein. The female terminal fitting 100 has a front end and a tube-shaped connecting portion 101 is provided at the front end of the female terminal fitting 100. A resilient contact piece 102 is provided inside the connecting portion 101 for resilient contact with an unillustrated mating male tab. The resilient contact piece 102 has a base at the upper side of the connecting portion 101 and extends back from the base. The resilient contact piece 101 then is curved arcuately down and again extends forward from a rear bottom of the connecting portion 101. However, the resilient contact piece 102 intercepts rays of light propagating in the inner space of the connecting portion 101 along forward and backward directions. As a result, infrared rays cannot measure the space between the resilient contact piece 102 and a contact portion 103 at the upper side. Hence, an improved female terminal fitting with a resilient contact piece has been developed. The improved terminal fitting has a resilient contact piece with a base at the rear side of the bottom surface of a connecting portion and a leading end that extends forward from the base.

[0005] Connectors and female terminal fittings have been miniaturized in recent years. Accordingly, the thickness of a metal plate before bending and a tolerance of precision errors in the bending process have been reduced to make the terminal fittings smaller. Small terminal fittings experience problems that terminal fittings of conventional size do not have. For example, the base of the resilient contact piece of the above-described female terminal fitting may be raised slightly by the resilience of the plate when folded at a specified position on the bottom surface. Although such a raised state may cause no problem for a female terminal fitting of conventional size, it may cause the smaller female terminal fitting to deviate from standard technical requirements.

[0006] The present invention was developed in view of the above problem and an object thereof is to provide a female terminal fitting in which a base portion of a resilient contact piece can be prevented from being raised even if the female terminal fitting is made smaller.

SUMMARY OF THE INVENTION

[0007] The invention relates to a female terminal fitting with a connecting portion connectable with a male tab of a mating male terminal fitting. Two contacts are provided on opposed walls of the connecting portion and are adapted to contact and tightly hold the male tab. One of the contacts is on a resilient contact piece configured for resilient contact with the male tab. A lock is substantially between a base of the resilient contact piece and the wall that has the contact to lock the base at a specified position. Accordingly, the resilient contact piece cannot be raised, and the female terminal fitting fulfills standard technical requirements even if the terminal fitting is small.

[0008] The connecting portion is substantially tubular, and hence can be inspected by light passing through the connecting portion.

[0009] The resilient contact piece preferably extends from the wall that faces the wall that has the other contact portion.

[0010] The connecting portion can be formed into the shape of a tube, for example, a rectangular tube or a cylindrical tube.

[0011] The base of the resilient contact piece may be provided at either the front side or the rear side in the connecting portion. Thus, the resilient contact piece may extend backward from the front side of the connecting portion or forward from the rear side of the connecting portion.

[0012] The locking construction may take any construction that positions the base of the resilient contact piece. Specifically, a cut may be made in a portion of the wall of the connecting portion, and the cut portion may be folded to bring the inner surface thereof into contact with the upper surface of the base. Alternatively a side edge of the base may partially serve as an engaging edge, and a locking hole may be formed in the wall for receiving the engaging edge.

[0013] Accordingly, the locking construction between the base and the wall positions the base of the resilient contact piece and prevents the base of the resilient contact piece from being raised. Thus, the female terminal fitting can fulfill standard technical requirements even if the terminal fitting is made small.

[0014] The locking construction preferably comprises an engaging edge that projects from a side edge of the base and a locking hole formed in the wall for receiving the engaging edge. Accordingly, the engaging edge that projects from the base fits into the locking hole in the wall during the bending of the female terminal fitting, thereby positioning the base of the resilient contact piece. Therefore, less labor is required as compared, for example, to a case where a cut is made in the wall and the cut portion is bent to bring the inner surface thereof into contact with the upper surface of the base.

[0015] The locking hole preferably is on a border of the wall adjacent to a lateral wall that is bent at an angle with respect to the wall portion.

[0016] Most preferably, the resilient contact piece projects in towards a mating side of the female terminal fitting with the male tab from its base.

[0017] The invention also relates to a method for forming a female terminal fitting. The method comprises providing a conductive plate, and stamping and bending the conductive plate to form a connecting portion with opposed facing walls. Two contacts are provided on the facing walls of the connecting portion. One of the contacts is provided on a resilient contact piece for resilient contact with the male tab. The walls are bent so that a lock is positioned substantially between a base of the resilient contact piece and the wall that has the contact locks the base at a specified position.

[0018] According to a preferred embodiment of the invention, the connecting portion is formed to be substantially tube-shaped.

[0019] Preferably, the resilient contact piece is formed to extend from the wall substantially facing the wall that has the other contact portion.

[0020] The locking construction preferably comprises an engaging edge that projects from a side edge of the base and a locking hole in the wall wherein the engaging edge is fitted into the locking hole when bending the walls. The locking hole preferably is formed on a border of the wall adjacent to a lateral wall that is bent at an angle with respect to the wall.

[0021] A cut preferably is made in a portion of the wall of the connecting portion for forming the lock. The cut is folded to bring the inner surface thereof into contact with the upper surface of the base, and a side edge of the base partially projects to serve as the engaging edge. The locking hole for receiving the engaging edge is provided in the wall.

[0022] The resilient contact piece preferably is formed to project in towards a mating side of the female terminal fitting with the male tab from its base.

[0023] These and other objects, features and advantages of the present invention will become more apparent upon reading of the following detailed description of preferred embodiments and accompanying drawings. It should be understood that even though embodiments are separately described, single features thereof may be combined to additional embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

[0024] FIG. 1 is a perspective view of a female terminal fitting according to one embodiment of the present invention.

[0025] FIG. 2 is a development of the female terminal fitting.

[0026] FIG. 3 is a side view of the female terminal fitting.

[0027] FIG. 4 is a front view of the female terminal fitting.

[0028] The female terminal fittings 1 are formed from electrically conductive plates 10 that are disposed at specified intervals on a strip 27, as shown in FIG. 2. The plates 10 are formed into the female terminal fittings 1 by stamping, cutting, bending, embossing and/or folding by a press.

[0029] The plate 10 is bent along specified bending lines 28 indicated by dotted line in the lower plate 10 in FIG. 2 in a specified procedure. However, the actual plate 10 looks like the plate 10 shown at the upper side of FIG. 2 without the bending lines 28. After formation, each female terminal fitting 1 is separated from the strip 27, e.g. when being connected with the respective wire 2. Moreover, the female terminal fittings 1 may be supplied on or from a reel.

[0030] The resilient contact piece 9 of the plate 10 is formed substantially straight. An engaging edge 25 projects laterally from the base 9A of the resilient contact piece 9. The engaging edge 25 is fitted into a locking hole 26 while the female terminal fitting 1 is bent. The side hole 26 extends continuously from the sidewall 15 at one side into the bottom wall 23.

[0031] A stabilizer 11 projects at an upper rear corner of the connecting portion 5. The stabilizer 11 fits into a groove (not shown) in the upper wall of a terminal accommodating chamber 21 to restrict movement of the female terminal fitting 1 along vertical or lateral directions and to stabilize the position of the female terminal fitting 1 in the terminal accommodating chamber 21.

[0032] A window 16 is cut or stamped substantially in the middle of the upper wall 12, and an engaging portion 14 projects at the front edge of the window 16 to engage a resin lock 13 in a connector 3.

[0033] The plates 10 are bent along the specified bending lines 28 while being passed through a bending apparatus (not shown) to produce the female terminal fittings 1 with the rectangular tubular connecting portion 5. In this process, the engaging edge 25 is fit into the locking hole 26 to position the base 9A of the resilient contact piece 9.

[0034] The female terminal fittings 1 formed in this way are separated from the strip 27, and a wire 2 with an insulation coating stripped off at one end is placed into the rear side of each female terminal fitting 1 from above. The wire 2 and the female terminal fitting 1 then are connected with each other by crimping, bending or folding the barrels 7, 8.

[0035] The leading end of the female terminal fitting 1 is inserted through a terminal insertion opening 20 of the connector 3 and into the terminal accommodating chamber 21. Sufficient pushing urges the female terminal fitting 1 to a proper mount position. Thus, the lock 13 engages the engaging portion 14 to prevent removal the female terminal fitting 1 from the terminal accommodating chamber 21. Thereafter, a retainer 22 is fit into the coupling portion 6 of the female terminal fitting 1 for doubly locking the female terminal fitting 1. The male tab 4 then can be inserted into the female terminal fitting 1. Consequently, the male tab 4 contacts the contact portions 9C, 18 and is held tightly, as shown in FIG. 10.

[0036] The engaging edge 25 engages the locking hole 26 between the base 9A and the sidewall 15 to position the base 9A of the resilient contact piece 9. Thus, the base 9A of the resilient contact piece 9 will not be raised. Thus, even if the female terminal fitting 1 is made smaller, standard technical requirements can be fulfilled.

[0037] The engaging edge 25 that projects from the base 9A is fit into the locking hole 26 in the side wall 15 when the female terminal fitting 1 is bent, and positions the base 9A of the resilient contact piece 9 in a longitudinal direction. Therefore, less labor is required as compared to, for example, a lock formed cutting a portion of the sidewall 15 and bending the cut portion to bring the inner surface thereof into contact with the upper surface of the base 9A.

[0038] The connecting portion 5 is a tube with open front and rear ends. Thus, rays of light can be passed through the inner space of the connecting portion 5 to test the space between the contact portions 18, 9C.

Claims

1. A female terminal fitting (1), comprising: a connecting portion (5) connectable with a male tab (4) of a mating male terminal fitting, and first and second contacts (9C, 18) provided at first and second substantially facing walls (23, 17) of the connecting portion (5) for contacting and tightly holding the male tab (4), wherein: the first contact (9C) is on a resilient contact piece (9) for resiliently contacting the male tab (4), and a locking construction (25; 26) is positioned between a base (9A) of the resilient contact piece (9) and the first wall (23) to lock the base (9A) at a specified position.

2. The female terminal fitting of claim 1, wherein the connecting portion (5) is substantially tube-shaped.

3. The female terminal fitting of claim 1, wherein the resilient contact piece (9) extends from the first wall (23).

4. The female terminal fitting of claim 1, wherein the locking construction (25; 26) comprises an engaging edge (25) projecting from a side edge of the base (9A) and a locking hole (26) formed in the first wall (23) for receiving the engaging edge (25).

5. The female terminal fitting of claim 4, wherein the locking hole (26) is formed on a border portion of the first wall (23) adjacent to a lateral wall (15) that is bent substantially normal to the first wall portion (23).

6. The female terminal fitting of claim 5, wherein the resilient contact piece (9) projects in towards a mating side of the female terminal fitting (1) with the male tab (4) from its base (9A).

7. A female terminal fitting (1), comprising: a substantially tubular connecting portion (5) having opposite first and second ends, a locking hole (26) formed transversely in the connecting portion (5) in proximity to the first end; and a resilient contact piece (9) in the tubular connecting portion (5), the resilient contact piece (9) having a base (9A) in proximity to the first end of the connecting portion (5) and a leading end (9B) in proximity to the second end of the connecting portion (5), an engaging edge (25) extending transversely from the base (9A) and engaged in the locking hole (26) for locking the base (9A) at a specified position in the connecting portion (5).

8. The female terminal fitting (1) of claim 7, wherein the connecting portion (5) defines a substantially rectangular tube with opposed substantially parallel first and second walls (23, 17) and opposed substantially parallel third and fourth walls (15, 15).

9. The female terminal fitting (1) of claim 8, wherein the locking hole (26) is formed in the fourth wall (15) and wherein a side of the base (9A) opposite the engaging edge (25) is unitary with the third wall (15), at least a portion of the base (9A) being in substantially face-to-face contact with the first wall (23).

10. A method for forming a female terminal fitting (1), comprising the following steps: providing a conductive plate (10), and stamping and bending the conductive plate (10) to form a connecting portion (5) having first and second substantially facing walls (23, 17), wherein first and second contacts (9C, 18) are provided at the pair of substantially facing walls (17, 23) of the connecting portion (5), the first contact (9C) being provided at a resilient contact piece (9) to be brought resiliently into contact with a male tab (4), and wherein when the walls (17, 23) are bent a locking construction (25; 26) positioned substantially between a base (9A) of the resilient contact piece (9) and the first wall (23) provided with the contact (9) becomes effective to lock the base (9A) at a specified position.

11. The method of claim 10, wherein the connecting portion (5) is substantially tubular.

12. The method of claim 11, wherein the resilient contact piece (9) is formed to extend from the first wall (23) substantially facing the second wall portion (17).

13. The method of claims 12, wherein the locking construction (25; 26) comprises an engaging edge (25) projecting from a side edge of the base (9A) and a locking hole (26) formed in the first wall (23) wherein the engaging edge (25) is fitted into the locking hole (26) when bending the walls (17, 23).

14. The method of claim 13, wherein the locking hole (26) is formed on a border of the first wall (23) adjacent to a lateral wall (15) bent substantially normal to the first wall (23).

15. The method of claim 14, wherein for forming the locking construction (25; 26), the method comprises: cutting a portion of the first wall (23) of the connecting portion (5) to form a cut portion; and folding the inner surface thereof into contact with the upper surface of the base (9A), a side edge of the base (9A) partially projects to serve as the engaging edge (25), whereas the locking hole (26) for receiving the engaging edge (26) is provided in the first wall portion (23).

16. The method of claim 15, wherein the resilient contact piece (9) is formed to project inwardly from the base (9A) towards a side of the female terminal fitting (1) that mates with the male tab (4).