EP2654140A1

EP2654140A1 - Seam closure of a receptacle contact

Info

Publication number: EP2654140A1
Application number: EP12164251.6A
Authority: EP
Inventors: John Marsh
Original assignee: Tyco Electronics UK Ltd
Current assignee: Tyco Electronics UK Ltd
Priority date: 2012-04-16
Filing date: 2012-04-16
Publication date: 2013-10-23
Anticipated expiration: 2032-04-16
Also published as: WO2013156367A1; EP2654140B1

Abstract

A receptacle contact for an electrical connector, comprising a seam 150 along the corner radii of the receptacle and which is defined by the junction of a first contacting edge 350 of a first sidewall 140 of the receptacle contact with a second contacting edge 360 of a second sidewall 135 of the receptacle. Each contacting edge is provided with interlocking features 378, 380 adapted to interlock with each other at each side of the seam 150 to fasten the first and second sidewalls together. This allows to either eliminate a box weld as the dovetail features on each side of the seam provides robust retention in each X, Y and Z planes, or if a seam weld is used, to provide increased resistance against ultrasonic cable splice stresses by having the seam weld located on the more rigid corner geometry.

Description

TECHNICAL FIELD OF THE INVENTION

The present invention relates to electrical connectors or terminals having a receptacle contact or terminal, and, more specifically, to receptacle contacts made from a stamped sheet which is folded into the overall shape of the receptacle contact and closed at a seam that joins two adjacent sides of the receptacle and a method of fabricating the same.

BACKGROUND OF THE INVENTION

Female electrical terminals having a receptacle contact or terminal are widely used in electronic and electrical applications, namely, in the automotive industry, for providing the connection to male electrical connectors of electrical equipment, such as circuit boards.
Various types and designs of receptacle contacts are commercially available.
In general, the receptacle contact is provided at the anterior part of the female electrical terminal that faces the mating male terminal, and has a box configuration with an inner hollow or cavity into which the male terminal is fitted. A common type of receptacle contact, also known as spring box contact, comprises one or more resilient contact arms in the inner side of the receptacle box for contacting the fitted male terminal. Such resilient arms, also known as spring arms, are deflected towards the inner wall of the receptacle contact by the fitted blade terminal, thereby producing a suitable pressure onto the blade terminal that helps to maintain the blade terminal in place and ensures a good electrical contact with the receptacle box.
The receptacle contact body is commonly made from a stamped blank or sheet material with a specific profile and which is bent by several bending operations into its overall shape. The contacting edges of the bent stamped blank define a seam that is conventionally closed with either a weld or an interlocking dovetail feature.
Welding is a simple method for fixing the seam of the box structure but has the disadvantage that a step of welding must be provided in addition to the bending process. Further, it has been shown that the vibrations caused by splice welding a cable to which the electrical terminal is connected may damage the seam welds on terminal spring boxes, thereby causing terminal function problems.
Alternative seam closure techniques that do not make use of a welding process have been proposed.
For instance, document DE 19741346 A1 describes a method for closing a spring box structure using only an interlocking dovetail at the box corner and which is prevented from opening by a locking angle on the edge of the dovetail feature. The dovetail feature is brought into contact with the mating face by being deflected outwards during an additional stamping operation after the box structure has been folded. However, although this method does not require a welding process, it has the limitations that the seam rigidity is not improved. Further, the technique requires a substantially square box corner and an additional stamping operation to activate the edge locking after box folding. It is also only possible to achieve a small locking angle on the edge of the dovetail feature plus the dovetail could potentially deflect inwards under stress both creating a low potential resistance to opening.
Another method for closing a cover for attachment to the exterior of an electrical terminal fitting without a weld process is described in document EP 0 837 529 B1 . The cover is formed by bending a stainless steel stamping into an angular tubular shape. A right side plate of the cover is formed so as to protrude above an upper plate. The protruding portion serves as a stabilizer and is provided with a pair of fitting grooves formed by cutting away into the protruding portion thereof. When the stamping is bent to the angular tubular shape, inserting members formed on the anterior and posterior ends of the upper plate are fitted into the corresponding fitting grooves to improve the stability of the cover.
A method for fastening co-planar edges without using a welding process is described in United States Patent No. 7,793,402 . This method is intended for fastening a docking casket for printed circuit boards while eliminating the use of a spot or fillet weld and a resulting burn mark in order to eliminate touch-up to coat the welded area. In the known method, a dovetailed feature provided on one of the edges to be fastened is inserted in an interlocking dovetail feature provided on the other edge, and the mating edges of the interlocked features are swagged for producing swag contact points and thereby, improving the strength of the interlocking mechanism. However, although this method provides a fastening of two edges without the use of a weld, a step for the additional process of swagging is required.
Further, since the known method requires the use of a punch of a certain shape, the punch needs to be precisely oriented with respect to the mating edges of the dovetail features.
Therefore, there is a need for receptacle contacts with a closure design and a method of producing same, that provides closed seams of improved strength, namely against ultrasonic vibrations, and which does not require or at least minimizes the use of welding processes.

SUMMARY OF THE INVENTION

The present invention aims at overcoming the disadvantages and shortcomings of the prior art techniques and an object thereof is to provide a receptacle contact with a seam closure and a method of making thereof, that provides a seam closure with improved resistance against stresses in the receptacle contact such as those caused by ultrasonic vibrations.
This object is solved by the present according to the independent claims. Advantageous embodiments of the invention are defined by the dependent claims.
According to the present invention, it is provided a receptacle contact for an electrical connector, comprising: a seam along a corner radii of the receptacle contact and which is defined by the junction of a first contacting edge of a first sidewall of the receptacle contact with a second contacting edge of a second sidewall of the receptacle contact; first interlocking means provided in the first contacting edge; and second interlocking means provided in the second contacting edge wherein the first and the second interlocking means are adapted to interlock with each other at each side of the seam to fasten the first and second sidewalls.
In a further development of the invention, the receptacle contact further comprises a third interlocking means and fourth interlocking means provided on the first and second contacting edges, respectively, that are adapted to interlock with each other at each side of the seam.
In a further development, the first and second interlocking means each comprise a protruding element and a receiving element, respectively, wherein the protruding element of the first interlocking means has a shape adapted to interlock with the receiving element of the second interlocking means, and the protruding element of the second interlocking means has a shape adapted to interlock with the receiving element of the first interlocking means.
The protruding elements of the first and second interlocking means may lie in the planes of the second and the first sidewalls, respectively, when interlocked with the respective receiving elements.
The protruding element of the first interlocking means may be provided as a flat tongue that protrudes away from the first contacting edge, said tongue being enlarged into a dovetail feature at an anterior side of the protruding element, opposed to the contacting edge.
The receiving element of the first interlocking means may be provided as a groove cut in the first sidewall and which recesses away from the first contacting edge, the receiving element having a complementary shape that substantially matches the shape of the corresponding protruding element of the second interlocking means.
In a further development of the invention, the first and second sidewalls are neither co-planar nor overlapping sidewalls when fastened to each other.
In a further development of the invention, the first and second sidewalls are substantially orthogonal to each other when fastened to each other.
According to a further development of the invention, the receptacle contact is made from a foldable stamped blank, and the first and second sidewalls are formed by bending two sides of the stamped blank so as to bring the first and second contacting edges into contact with each other.
The third interlocking means may have a protruding element and a receiving element with shapes that are defined by the profile of the first contacting edge as a mirrored image of the first interlocking means.
According to an embodiment of the invention, the receptacle contact is a spring box terminal.
In a further development of the invention, the receptacle contact has an opening on a rear side adapted to receive an anterior member of a female electrical terminal and an opposed opening on a front side adapted to receive a male electrical connector so as to establish an electrical connection between the female electrical terminal and the male electrical terminal.
The present invention also provides a method of making a receptacle contact from a foldable stamped blank, the method comprising; providing an upper face plate in the stamped blank with a free edge along a longitudinal direction (X) that defines a first contacting edge of a first sidewall, the free edge of the upper face plate having a profile that defines a first interlocking means in the first contacting edge; providing a lower face plate in the stamped blank with a free edge along the longitudinal direction (X) that defines a second contacting edge of a second sidewall, the free edge of the lower face plate having a profile that defines a second interlocking means in the second contacting edge; bending the stamped blank in a direction transverse to the longitudinal direction (X) of the first and second contacting edges so as to bring the first and second contacting edges into contact with each other, wherein the junction of the first and second contacting edges defines a seam along a corner radii of the receptacle contact; and interlocking the first and second interlocking means with each other so as to fasten the first and second sidewalls; wherein the first and the second interlocking means are adapted to interlock with each other at each side of the seam.
In a further development of the invention, the profiles of the first and the second interlocking means each define protruding elements and receiving elements in the first and second contacting edges, respectively, wherein the protruding element and the receiving element of the first interlocking means are adapted to be interlocked with the receiving element and the protruding element of the second interlocking means, respectively, each protruding element having a flat tongue that extends from the respective contacting edge and having a dovetail feature at an anterior end; the method further comprising: inserting the flat tongue of the first interlocking means in the corresponding receiving element of the second interlocking means by a given depth such that the dovetail feature protrudes from the receiving element in the second sidewall; and bending the dovetail feature towards the second sidewall so as to fit the dovetail feature in the receiving element of the second interlocking means.
According to a further development of the invention, the method further comprises: inserting the flat tongue of the protruding element of the second interlocking means in the corresponding receiving element of the first interlocking means by a given depth such that the dovetail feature of the protruding element protrudes from the receiving element in the first sidewall; and bending the dovetail feature towards the first sidewall so as to fit the dovetail feature in the receiving element of the first interlocking means.
Hence, according to the present invention, the seam closure of the receptacle contact is located along a corner radius of the receptacle contact.
Further, the contacting edges defining the seam have a profile with interlocking dovetail type features that are defined on both flat adjacent walls at each side of the seam. As the dovetail features on each side of the seam provides robust retention in each X, Y and Z planes, this allows either eliminating a seam weld or, if a seam weld is used, providing increased resistance against ultrasonic stresses by having the seam weld located on the more rigid corner geometry.
The accompanying drawings are incorporated into and form a part of the specification for the purpose of explaining the principles of the invention. The drawings are not to be construed as limiting the invention to only the illustrated and described examples of how the invention can be made and used.

BRIEF DESCRIPTION OF THE FIGURES

Further features and advantages will become apparent from the following and more particular description of the invention as illustrated in the accompanying drawings, in which:

Fig. 1 is a perspective view of a receptacle contact for use in an electrical connector according to an embodiment of the present invention, when viewed from a front side and showing a top face and a left sidewall of the receptacle contact;
Fig. 2 is a perspective view of the receptacle shown in Fig. 1 when viewed from the front side and showing the top face and a right sidewall of the receptacle contact;
Fig. 3 shows a perspective view of the receptacle shown in Fig. 1, when viewed from a rear side of the receptacle contact, opposed to the front side, and showing the top face and the right sidewall of the receptacle contact;
Fig. 4 is a multi-view of the receptacle contact shown in Figs. 1 to 3 showing: a top view (image on the centre), a side view of the left sidewall (image on the left of the top view) and a side view of the right sidewall (image on the right of the top view) of the receptacle contact;
Fig. 5 is a multi-view of the receptacle shown in Figs. 1 to 3 showing (from the left to the right of Fig. 5): a side view of the left sidewall, a front view, and a section view when viewed from the right side of the receptacle contact;
Fig. 6 shows a bottom view of the receptacle contact shown in Figs. 1 to 3;
Fig. 7 is a perspective view of a stamped blank from which the receptacle contact of Figs. 1 to 3 is formed and showing an inner side of the stamped blank over which spring contact arms are bended;
Fig. 8 is a multi-view of the stamped blank of Fig. 7 showing (from left to right and from top to bottom of Fig. 7): a side view when viewed from the front side, a top view of the inner side of the stamped blank with the bended spring contact arms, a side view when viewed from the rear side, and a side view when viewed from a contacting edge of the stamped blank;
Fig. 9 is a perspective view of the receptacle shown in Figs. 1 to 3 fitted to a conventional female electrical terminal.

DETAILED DESCRIPTION OF THE INVENTION

Advantageous embodiments of a receptacle contact with a closure design according to the invention will now be described in further detail with reference to the accompanying drawings.
Figure 1 is a perspective view of a receptacle contact according to an embodiment of the present invention for use in an electrical connector.
The receptacle contact 100 has a box structure with an inner, hollowed core 110 that extends in a longitudinal direction X between an opening provided on a rear side 120 of the receptacle contact 100 for receiving an anterior member 210 of an electrical connector, such as a female electrical terminal 200 (see Fig. 9), and an opening in a front side 125, opposed to the rear side 120, and through which it is inserted a blade of a male terminal (not shown). The receptacle contact 100 is preferably made from a metallic sheet in order to electrically couple the male terminal to the female electrical terminal 200.
In the illustrated embodiment, the receptacle contact 100 has a substantially rectangular cross-section defined by a base face 130 and a top face 135, which are disposed parallel to each other, and by a left sidewall 140 and a right sidewall 145, which are arranged substantially orthogonal to the base and top faces 130, 135. The rectangular cross-section is suitable for use with blade terminals. However, the closure design of the present invention may also be applied to receptacle structures for fitting other types of terminals, such as pin terminals, and having a different overall shape, such as a polygonal or a circular cross-section.
As will be described later, the receptacle contact 100 is made from a stamped blank 300 that is folded along certain bending edges in several bending operations into the overall shape of the receptacle contact 100. The final shape of the folded stamped blank 300 is fixed by fastening the free edges of two adjacent sidewalls of the receptacle contact 100, a first sidewall and a second sidewall, that are brought into contact with each other in the bending process. The junction of these adjacent sidewalls, which in the illustrated embodiment correspond to the top face 135 and the left sidewall 140 of the receptacle contact 100, define a seam 150 that is located along the closing corner radii of the receptacle contact 100 and that extends along a closing edge of the receptacle contact 100 in the longitudinal direction X. The location of the seam 150 along the corner radii of the receptacle box 100, more specifically at the midpoint of the corner radii, allows increasing the rigidity of the seam 150 along its entire length, in contrast to closure designs in which a seam is provided on a sidewall of the box.
In the present embodiment, the top face 135 and the left sidewall 140 are substantially orthogonal, therefore, defining a box corner radii of substantially 90º, and are fastened to each other by interlocking features provided along the seam 150 as will be described later. These interlocking features prevent any relative displacement of the fastened walls in the three X, Y and Z orthogonal directions.
The external surface of the receptacle contact 100 may be provided with additional features for fixing and/or orienting the receptacle contact 100 with respect to a plastic housing of the mated male terminal (not shown). As shown in Fig. 1, the box receptacle is provided with a locking latch 160 in the top face 135 of the receptacle contact 100. When the receptacle contact 100 is inserted in the housing, the locking latch 160 is pressed against the receptacle contact 100 and then re-opens to a locking position when the receptacle contact 100 is completely fitted so as to prevent its accidental removal. The locking latch 160 may be provided as a cut-way tab that is bended away from the top face 135. A similar locking latch 160 may also be provided on the base face 130 of the receptacle contact 100 (see Fig. 6).
One or more orienting ribs 162, 164 may be provided in the top face 135 and/or in the base face 130 for orientating the receptacle contact 100 in the housing of the male connector.
Crimping tabs 166 to 168 may also be provided in the lateral sidewalls 140, 145 of the receptacle contact 100, at an intermediate distance between the front side 125 and rear side 120, for providing an additional fixation of the receptacle contact 100 to the female electrical terminal 200 (see Fig. 9).
As shown in Figs. 1 - 3, two pairs of resilient contact elements 170 and 175 may be provided on the inner side 110 of the base face 130 and the top face 135, respectively, of the receptacle contact 100 for griping the blade of the male electrical connector (not shown) and establishing a good electrical contact therewith.
Referring to the section view of the receptacle contact 100 shown in Fig. 5, the resilient contact elements 170 and 175 may be formed in a conventional fashion as contact arms protruding from the base and top faces 130, 135 of the receptacle contact 100 and which are reversibly bended on a bending section 178 at the front side of the receptacle contact 100 so as to extend inwards over the inner side 110 of the respective base and top faces 130, 135. The bending section 178 and the shape of the resilient contact arms 170, 175 are selected so as to produce a suitable spring force against the fitted blade of the male terminal when the resilient contact arms 170, 175 are deflected towards the respective inner walls of the receptacle contact 100.
The length and shape of the resilient contact arms 170, 175 as well as their separation from the inner sides of the base face 130 and the top face 135, respectively, of the receptacle contact 100 may be selected so as to allow the anterior member 210 of the female electrical terminal 200 to be contacted by the resilient contact arms 170, 175 (see Fig. 9).
Preferably, the resilient contact arms 170, 175 are provided on both top and base faces 135, 130 of the receptacle contact 100. However, other configurations may be envisaged in which the resilient contact elements are provided in any of the inner walls of the receptacle contact 100. The number, shape and length of the resilient contact elements are also not limited to the illustrated example. Namely, the receptacle contact 100 may comprise a single resilient contact element or more than those illustrated in Figs. 1 - 3.
As mentioned above, the receptacle contact 100 may be made from a foldable, stamped blank that is folded by a sequence of folding operations into its final overall shape.
Fig. 7 is a perspective view of a stamped blank 300 from which the receptacle contact of Figs. 1 to 3 is formed and showing the side of the stamped blank that faces the inner side 110 of receptacle contact walls.
The stamped blank 300 is made from a metal sheet, preferably, stainless steel or a copper alloy, having a cut profile that defines the receptacle shape as well as the interlocking features for fastening the seam 150.
Fig. 8 shows multi-views of the stamped blank shown in Fig. 7. From the left to the right, and from the top to the bottom, Fig. 8 shows a side view of the stamped blank 300 when viewed from the front side 125 of the receptacle contact 100, a top view showing the walls of the receptacle contact 100 from its inner side 110, a side view of the stamped blanked 300 when viewed from the rear side 120 of the receptacle contact 100, and a side view of the stamped blank 300 when viewed from a contacting edge of the seam 150.
Referring to the top view in Fig. 8, and starting from the upper side of the drawing downwards, the stamped blank 300 has an upper face plate 310, which defines the left sidewall 140 of the receptacle contact 100 with respect to its front side 125, an intermediate face plate 320 defining the base face 130 of the receptacle contact 100, another intermediate face plate 330 that defines the right sidewall 145 of the receptacle contact 100, and a lower face plate 340 that defines the top face 135 of the receptacle contact 100.
The free edge 350 of the upper face plate 310 and the free edge 360 of the lower face plate 340 along the longitudinal direction (X) define contacting edges that are brought into contact with each other during the folding process of the stamped blank 300. The contacting edges 350 and 360 have a straight profile along a certain length in the longitudinal direction X that defines a straight seam 150 along the closing corner of the receptacle contact 100, which is interrupted by cut interlocking features as will be described below.
The seam closure design according to the present invention will now be described with reference to Fig. 8. As shown in the top view of Fig. 8, the contacting edges 350 and 360 of the upper and lower face plates 310 and 340 of the stamped blank 300 are each provided with interlocking features defined by cutting the contacting edge profile and which are adapted to be interlocked with matching interlocking features provided at corresponding positions in the opposed contacting edge for closing the seam 150. In the illustrated embodiment, the upper and lower face plates 310 and 340 correspond to the first and second sidewalls of the receptacle contact 100, respectively, which are to be fastened together.
Referring to Fig. 8, first interlocking means 370 are provided in the contacting edge 350 of the upper face plate 310 at a given distance from the transversal edge 355 at the receptacle front side 125. The first interlocking means 370 comprises a protruding element 372 that is immediately followed by an adjacent, receiving element 374. The protruding element 372 is provided as a flat protrusion that extends away from the contacting edge 350 in the plane of the upper face plate 310 along a direction (Y) transverse to the longitudinal direction (X). The protruding element 372 is to be inserted in a receiving element 382 provided at a corresponding position in the contacting edge 360 of the lower face plate 340 and having a complementary, shape that matches the shape of the protruding element 372. As shown in Fig. 8, the protruding element 372 in the upper contacting edge 350 has a flat lobe 376 with rounded edges that is connected to the contacting edge 350 by a neck or tongue 378 of substantially parallel edges. The width of the tongue 378 in the longitudinal direction (X) is smaller than the diameter of the rounded lobe 376, one of the tongue edges being recessed with respect to the lobe 376 for defining an interlocking dovetail feature that blocks relative displacements in the Y direction.
The shape of the receiving element 374 of the first interlocking means 370 is adapted to fit a protruding element 384 provided at a corresponding position in the contacting edge 360 of the lower face plate 340. As shown in Fig. 8, the receiving element 374 of the first interlocking means 370 is a recession or groove that is cut in the upper face plate 310 and which recesses in the transverse direction (Y) away from the straight profile of the contacting edge 350, and therefore, from the corner formed by the upper and lower contacting edges 350 and 360 when joined together.
In order to improve the interlocking effect, the protruding element 372 and the receiving element 374 of the first interlocking means 370 may be defined side by side along the longitudinal direction (X), one of the parallel edges of the protruding element tongue 378 being an extension of a parallel edge of the receiving element 374. However, an alternative configuration is also envisaged, in which the receiving element 374 and the protruding element 372 are separated by a non-zero distance along the longitudinal direction X.
In the present embodiment, the shape of the receiving element 374 of the first interlocking means 370 substantially follows the shape obtained by a mirror reflection of the protruding element 372 in a plane along the Y direction, followed by a mirror reflection in a plane along the X direction.
The receiving element 382 and protruding element 384 provided at corresponding positions in the contacting edge 360 of the lower face plate 340 form a second interlocking means 380 of the lower face plate 340 and are defined with substantially a complementary shape that matches the shape of the protruding element 372 and receiving element 374 of the first interlocking means 370, respectively.
In addition, a third interlocking means 390 may be provided on the contacting edge 350 of the upper face plate 310, close to the transversal edge 365 at the rear side 120 of the receptacle contact 100 for interlocking with a matching, fourth interlocking means 395 provided at a corresponding position in the contacting edge 360 of the lower face plate 340. Preferably, the third interlocking means 390 is defined with an edge profile that is essentially a mirrored image of the first interlocking means 370 in a plane along the transverse direction (Y). Thus, similarly to the first interlocking means 370, the third interlocking means 390 comprises a protruding element 392 and a receiving element 394, which are to be interlocked with a matching receiving element 396 and a protruding element 398 of the fourth interlocking means 395, respectively.
The bending process of the stamped blank 300 will now be described with reference to Fig. 8, in which the bending edges are indicated by dashed lines. After the resilient contact arms 170, 175 have been reversely bent over the inner side of the respective base and top faces 130 and 135 in the stamped blank 300, the upper face plate 310 and the intermediate face plate 330 are bent upwards with respect to the inner side of the base plate 320 so as to form upright left and right sidewalls 140 and 145, respectively, that are substantially orthogonal to the base 130 of the receptacle contact 100. The lower face plate 340 is then bent with respect to the right sidewall 145 by approximately 90º so as to form the top face 135 of the receptacle contact 100.
In this bending step, the free contacting edges 350, 360 of the upper and lower face plates 310 and 340 are brought into contact with each other. The interlocking means on the respective contacting edges are then interlocked, thereby fastening the left sidewall 140 and the top face 135 of the receptacle contact 100. As shown in Figs. 1 to 3, the upper and lower face places 310 and 340 do not overlap each other after the bending process, but only contact with each other along the seam 150.
The following interlocking process is then performed for fastening the contacting edges 350 and 360. When the contacting edge 350 of the upper face plate 310 (left sidewall 140) and the contacting edge 360 of the lower face plate 340 (top face 135 of the receptacle contact 100) are brought into contact, the flat protruding element 384 of the interlocking means 380 in the top face 135, which are initially in the same plane, is partially inserted through the corresponding receiving element 374 of the interlocking means 370 provided in the upper face plate 310 (left sidewall 140) of the receptacle contact 100 by exerting a light pressure in the Z direction (see Fig. 1), which is transverse to the plane of the top face 135.
This causes the protruding element 384 to be inserted in the receiving element 374 over a depth that corresponds essentially to the thickness of the protruding element 384, which is the thickness of the stamped blank 300, and without bending the protruding element 384. At this stage, part of the tongue 386 and the lobe 388 of the protruding element 384 protrude away from the left sidewall 140 in a direction parallel to the top face 135 of the receptacle contact 100. These protruding parts are then bended towards the left sidewall 140 by substantially 90º so as to be fitted in the matching receiving elements 374 in the left sidewall 140 with respect to the left sidewall 140.
Therefore, the protruding element 384 of the second interlocking means 380 is interlocked with the receiving element 374 in the plane of the left sidewall 140, at the other side of the seam 150, thereby blocking a relative displacement of the top face 135 in the Z and X directions.
The protruding element 372 of the first interlocking means 370 provided in the left sidewall 140 is then fitted in the corresponding receiving element 382 of the second interlocking means 380 provided on the top face 135 of the receptacle contact 100 in a similar way as described above for the protruding element 384. The protruding element 372 of the first interlocking means 370 becomes then locked in the top face 135 of the receptacle contact 100 that is on the other side of the closed seam 150, thereby blocking displacements of the left sidewall 140 in the Y and X directions.
As a consequence, the combination of the first and second interlocking means 370 and 380 allows fastening adjacent walls of the receptacle contact 100 along the seam 150 with a closure design that prevents a relative displacement of the fastened walls in all three orthogonal directions X, Y, and Z and without the need of a welding process.
Similarly to the interlocking process described above, the third and fourth interlocking means 390 and 395 provided at the upper and lower contacting edges 350 and 360, respectively, are also interlocked at each side of the seam 150.
As shown in Fig. 1, the contacting edges 350 and 360 may be slightly bended so as to form a rounded corner. The seam 150 is then located at the midpoint of the corner radii.
As will be immediately realized by those skilled in the art, the exact sequence of bending and/or interlocking steps for arriving at the folded, interlocked shape of the receptacle contact 100 may be different from the sequence described above. Namely, the interlocking features 372, 384, 392, 396 may be bended prior to bending the faces of the stamped blank 300.
In the illustrated embodiment, the first to fourth interlocking means have protruding elements and receiving elements with a similar shape. However, interlocking dovetail features of other shapes may be envisaged. In particular, since the first and third interlocking means defined on the same contacting edge are independent from each other, they may be provided with interlocking dovetails features of different shapes as long as corresponding mating interlocking means are provided on the other contacting edge.
Furthermore, the number of interlocking means provided along the contacting edges is not limited to the illustrated embodiment, and additional interlocking means similar to the first and/or second interlocking means described above may be provided along the longitudinal length of the receptacle contact 100 in order to reinforce the strength of the seam closure, particularly, in the case of receptacle contacts of a considerable longitudinal length.
Figure 9 shows the receptacle contact of Figs. 1 - 3 fitted to the anterior member 210 of a conventional female electrical terminal 200, which is to be mated with a pin or blade contact of a male electrical terminal (not shown).
The dimensions of the receptacle contact 100 are selected so as to substantially match the dimensions of the anterior member 210 and/or of the blade of the mating male terminal.
Namely, the length of the receptacle contact 100 in the longitudinal direction X, transverse to the rear side 120 and the front side 125, depends on the length of the anterior member 210 to be covered. In the illustrated example, the receptacle contact 100 partially covers the anterior member 210.
The anterior member 210 of the female electrical terminal 200 is formed by two parallel blades 240 and 250 that extend from the body of the female electrical terminal 200 and between which the blade of the mating male terminal is to be mated. Crimping sections 220, 225 are provided on a posterior part of the terminal body for crimping an end of an electrical wire or cable (not shown). A conventional carrier strip 230 is provided at the posterior end of the terminal body for facilitating the termination of the female electrical terminal 200 and which can be removed once the female electrical terminal 200 is terminated. However, as immediately recognized by a person skilled in the art, the receptacle contact of the present invention may be modified in order to fit to other types of female electrical terminals.
By providing the seam closure of the receptacle contact along a corner radii of the receptacle contact 100, and interlocking dovetail type features on both sides of the seam 150, at each of the adjacent sidewalls, a robust retention of the fastened sidewalls is provided in all three orthogonal directions X, Y and Z, which allows for eliminating a welding step of a seam, or, if a seam weld is used, to improve the resistance of the seam weld against ultrasonic vibrations.
Further technical advantages of the closure technique of the present invention are as follows.
First, the receptacle seam closure is resistant to cable ultrasonic splice weld vibrations. In particular, the robust profiled dovetail retention in the three directions X, Y and Z makes possible to eliminate seam welding. Furthermore, there is a potential to keep the weld by locating the seam in lower stress area.
Secondly, the seam location at the mid point of the box corner radii allows increasing the rigidity of the seam 150 along its entire length, in contrast to closure designs in which the seam 150 is provided on one of the box faces.
Thirdly, the presence of the dovetail features on both adjacent flat surfaces of the receptacle contact 100 enables any size of the box corner radii, as opposed to the technique of DE 19741346 A1 in which the dovetail locking design is only possible on a substantially square corner.
Further, in contrast to DE 19741346 A1 , which requires a small locking angle to be formed on the dovetail edge, which limits potential resistance to opening, the interlocking dovetail features 372, 374, 382, 384 of the present invention are profiled shapes on the box faces, thereby enabling a robust dovetail form.
Further, since the interlocking dovetail features of the present invention are interlinked during the folding operation, it is not required to provide additional fastening steps such as welding or swaging for improving the interlocking strength. For instance, the technique of DE 19741346 A1 requires an additional stamping operation to open the dovetail and engage the locking edge with the mating face.
Furthermore, the interlocking mechanism of the present invention requires a significant force for causing catastrophic rupture of the interlocked features. In contrast thereto, in the technique of DE 19741346 A1 the dovetail feature can be potentially deflected inwards under comparatively much lower forces.
Although the above embodiments were described with reference to a receptacle contact that is to be fitted in the anterior part of an electrical contact, and most particularly to a spring box receptacle, the principles of the closure design of the present invention may be conveniently applied to other receptacle structures than those illustrated in Figs 1 to 3.
For instance, the rear and front sides of the receptacle contact may have a different relative orientation than illustrated in the present drawings. Further, although the surface area of the top and base faces 135, 130 of the receptacle contact 100 shown in Figs. 1 to 3 is larger than the surface area of the left and right sidewalls 140,145, the principles of the present invention may be applied to receptacle contacts having other relative dimensions. Namely, the surface of the top and base faces may be smaller or substantially the same as the surface of the left and right sidewalls. In addition, the closure design of the present invention may be applied to electrical connectors having a receptacle contact that is an integral part of the connector body.
The closure design of the present invention can also be applied for receptacle boxes intended for other applications, such as protection covers, in which at least two adjacent walls are fastened by a seam located along the corner radii of the receptacle.
The closure design of the present invention may also be applied in receptacle contacts or boxes having closing seams in more than one receptacle corner. In particular, although the closing seam 150 was described above as being located along the edge defined by the junction of the top face 135 with the left sidewall 140 of the receptacle contact 100, other configurations of the receptacle contact and of the corresponding stamped blank may be envisaged in which one or more closing seams are provided at the edges defined by the top face with the right sidewall and/or at the edges defined by the base face and the left and/or right sidewalls of the receptacle contact.
Finally, the description of the receptacle contact 100 in terms of top/base faces and left/right sidewalls was done for simplicity purposes only, and should not be construed as being limitative in terms of the orientation of the receptacle contact 100 itself, namely, with respect to the electrical terminals with which the receptacle contact is to be mated.

REFERENCE NUMERAL LIST

Reference Numeral	Description
100	Receptacle contact
110	hollowed core, inner side of receptacle contact
120	rear side
125	front side
130	base face
135	top face
140	left sidewall
145	right sidewall
150	Seam
160	locking latch
162, 164	orienting ribs
166 to 168	crimping tabs
170, 175	resilient contact arms
178	bending section
200	female electrical terminal
210	anterior member
220, 225	crimping sections
230	carrier strip
240, 245	parallel blades
300	stamped blank
310	upper face plate, left sidewall
320	intermediate face plate, base face
330	intermediate face plate, right sidewall
340	lower face plate, top face
350	free edge of upper face plate
355	transversal edge of stamped blank at front side
360	free edge of lower face plate
365	transversal edge of stamped blank at rear side
370	first interlocking means
372	protruding element of first interlocking means
374	receiving element of first interlocking means
376	lobe of protruding element
378	tongue of protruding element
380	second interlocking means
382	receiving element of second interlocking means
384	protruding element of second interlocking means
386	tongue of protruding element 384
388	lobe of protruding element 384
390	third interlocking means
392	protruding element of third interlocking means
394	receiving element of third interlocking means
395	fourth interlocking means
396	protruding element of fourth interlocking means
398	receiving element of fourth interlocking means

Claims

A receptacle contact for an electrical connector, comprising:
a seam (150) along a corner radii of the receptacle contact and which is defined by the junction of a first contacting edge (350) of a first sidewall (140, 310) of the receptacle contact with a second contacting edge (360) of a second sidewall (135, 340) of the receptacle contact;

first interlocking means (370) provided in the first contacting edge (350); and

second interlocking means (380) provided in the second contacting edge (360);

wherein the first and the second interlocking means (370, 380) are adapted to interlock with each other at each side of the seam (150) to fasten the first and second sidewalls.
A receptacle contact according to claim 1, further comprising:
third interlocking means (390) and fourth interlocking means (395) provided on the first and second contacting edges, respectively;

wherein the third and the fourth interlocking means are adapted to interlock with each other at each side of the seam (150).
A receptacle contact according to claim 1 or claim 2, wherein:
the first and second interlocking means (370, 380) each comprise a protruding element and a receiving element, respectively,

the protruding element (372) of the first interlocking means (370) has a shape adapted to interlock with the receiving element (382) of the second interlocking means (380), and

the protruding element (384) of the second interlocking means (380) has a shape adapted to interlock with the receiving element (374) of the first interlocking means (370).
A receptacle contact according to claim 3, wherein:
the protruding elements of the first and second interlocking means (380) lie in the planes of the second and the first sidewalls, respectively, when interlocked with the respective receiving elements.
A receptacle contact according to any one of claims 3 to 4, wherein:
the protruding element (372) of the first interlocking means (370) is a flat tongue (378) that protrudes away from the first contacting edge (350), said tongue (378) being enlarged into a dovetail feature (376) at an anterior side of the protruding element (372), opposed to the contacting edge (350).
A receptacle contact according to any one of claims 3 to 5, wherein:
the receiving element (374) of the first interlocking means (370) is a groove cut in the first sidewall (140, 310) and which recesses away from the first contacting edge (350), and

the receiving element (374) has a complementary shape that substantially matches the shape of the corresponding protruding element (384) of the second interlocking means (380).
A receptacle contact according to any one of claims 1 to 6, wherein:
the first and second sidewalls are neither co-planar nor overlapping sidewalls when fastened to each other.
A receptacle contact according to any one of claims 1 to 7, wherein:
the first and second sidewalls are substantially orthogonal to each other when fastened to each other.
A receptacle contact according to any one claims 1 to 8, wherein:
the receptacle contact is made from a foldable stamped blank (300), and

the first and second sidewalls are formed by bending two sides of the stamped blank (300) so as to bring the first and second contacting edges (350, 360) into contact with each other.
A receptacle contact according to claim 3, wherein the third interlocking means (390) has a protruding element (392) and a receiving element (394) with shapes that are defined by the profile of the first contacting edge (350) as a mirrored image of the first interlocking means (370).
A receptacle contact according to any one of claims 1 to 10, wherein the receptacle contact is a spring box terminal (100).
A receptacle contact according to any one of claims 1 to 11, wherein the receptacle contact has an opening on a rear side (120) adapted to receive an anterior member (210) of a female electrical terminal (200) and an opposed opening on a front side (125) adapted to receive a male electrical connector so as to establish an electrical connection between the female electrical terminal (200) and the male electrical connector.
A method of making a receptacle contact from a foldable stamped blank, comprising:
providing an upper face plate (310) in the stamped blank (300) with a free edge along a longitudinal direction (X) that defines a first contacting edge (350) of a first sidewall (140, 310), the free edge of the upper face plate (310) having a profile that defines a first interlocking means (370) in the first contacting edge (350);

providing a lower face plate (340) in the stamped blank (300) with a free edge along the longitudinal direction (X) that defines a second contacting edge (360) of a second sidewall (135, 340), the free edge of the lower face plate (340) having a profile that defines a second interlocking means (380) in the second contacting edge (360);

bending the stamped blank (300) in a direction transverse to the longitudinal direction (X) of the first and second contacting edges (350, 360) so as to bring the first and second contacting edges (350, 360) into contact with each other, wherein the junction of the first and second contacting edges (350, 360) defines a seam (150) along a corner radii of the receptacle contact; and

interlocking the first and second interlocking means (370, 380) with each other so as to fasten the first and second sidewalls;

wherein the first and the second interlocking means (370, 380) are adapted to interlock with each other at each side of the seam (150).
A method according to claim 13, wherein the profiles of the first and the second interlocking means (370, 380) each define protruding elements (372, 384) and receiving elements (374, 382) in the first and second contacting edges (350, 360), respectively, wherein the protruding element (372) and the receiving element (382) of the first interlocking means (370) are adapted to be interlocked with the receiving element (382) and the protruding element (384) of the second interlocking means (380), respectively, each protruding element (372, 384) having a flat tongue (378) that extends from the respective contacting edge (350, 360) and having a dovetail feature (376, 388) at an anterior end;
the method further comprising:
inserting the flat tongue (378) of the first interlocking means (370) in the corresponding receiving element (382) of the second interlocking means (380) by a given depth such that the dovetail feature (376) protrudes from the receiving element (383) in the second sidewall (135, 340); and

bending the dovetail feature (376) towards the second sidewall (135, 340) so as to fit the dovetail feature in the receiving element (382) of the second interlocking means (380).
A method according to claim 14, further comprising:
inserting the flat tongue (386) of the protruding element (384) of the second interlocking means (380) in the corresponding receiving element (374) of the first interlocking means (370) by a given depth such that the dovetail feature (388) of the protruding element (384) protrudes from the receiving element (374) in the first sidewall (140, 310); and

bending the dovetail feature (388) towards the first sidewall (140, 310) so as to fit the dovetail feature (388) in the receiving element (374) of the first interlocking means (370).