Electrical terminal

Abstract: An electrical female terminal (10) of one-piece construction comprises a contact portion (12) at one end and an attachment portion (14) at an opposite end for attaching the terminal (10) to an electric cable (15). The contact portion (12) includes a split socket (16) and a pair of integrally attached, longitudinal contact arms (26) disposed inside the split socket (16). The longitudinal contact arms (26) have rearward abutting plates (28) that have flanges (30) that engage the inside surface of the socket (16) to provide a solid anchor for the longitudinal contact arms (26) to extend forwardly in cantilevered fashion. The longitudinal contact arms (26) have diverging medial portions (32) and converging forward portions (35) that provide deflectable contact fingers (35) for engaging opposite sides of a pin terminal when inserted into the socket (16).

Description: This invention relates to a female electrical terminal, for example an electrical terminal which in use is attached to an electric cable for use in a sealed electrical connector of a "plug through" type. US-A-4,946,402 discloses a "plug through" type sealed electrical connector having an elastomeric seal mounted on the cable end of a connector body before installation of the electrical female terminals which are attached to the ends of electric cables. These electrical female terminals are inserted into terminal cavities of the connector body through aligned holes in the elastomeric seal, that is, the electrical female terminals are "plugged through" the seal. The holes are adapted to fit tightly around the electric cables when the electrical female terminals are installed so as to seal the cable end of the electrical connector. It is known to provide electrical female terminals of two-piece construction for these "plug through" arrangements, which comprise a main terminal member and a protective cap or hood. In these known terminals, the main terminal member has spring contact fingers at one end and crimp means at the other end to attach the main terminal member to the end of an electric cable. The protective cap or hood surrounds the spring contact fingers to protect the fingers and provide a round, protrusion-free contact end which facilitates insertion of the electrical female terminals through tight holes in the elastomeric seal. This two-piece terminal is expensive to manufacture because of poor material utilization and slow manufacturing processes. Two strips of stock are required and the assembly speed is generally limited to two hundred parts per minute. Quality control and inspection are also difficult because contact plating is not accessible. US-A-3,538,491 discloses an electrical pin receptacle of one piece construction which comprises a spring contact assembly disposed inside a barrel member. The spring contact assembly and the barrel member are integrally attached to each other by an extension reversely bent upon itself. This design reduces construction costs because of its one-piece construction. However, the pin receptacle is not suitable for a sealed electrical connector of the "plug through" type described above because the pin receptacle does not have any provision for attaching the pin receptacle to an electric cable. Moreover, the pin receptacle does not have a round, protrusion-free contact end that would facilitate the pin receptacle being pushed through a tight hole in an elastomeric seal easily. This is due primarily to the presence of a flared mouth and cooperating ears which provide a stop to limit movement of the pin receptacle within a hole of a printed circuit board or carrier member. US-A-4,715,833 discloses an electrical socket member having a split socket section provided with three equally spaced, inwardly directed ribs. The ribs firmly engage the outer surface of a pin member when this is inserted into the split socket section. The electrical socket member is also of one-piece construction. However, it has several drawbacks. For instance, the ribs are non-compliant contacts and consequently the socket member has high engagement force characteristics, tight tolerance requirements, high contact stress and little tolerance for misalignment of the pin terminal. Moreover the socket member has a pin receiving receptacle which includes a conical support section having a 180° opening which provides resilience for the split socket section to receive a pin terminal. This opening exposes sharp edges that make the socket member unsuitable for use in a sealed electrical connector of the "plug through" type. In addition, non-compliant contacts in the form of inwardly directed ribs require a guide section which is difficult to form. This limits the choice of materials for the socket member and also reduces the suitability of the socket member for a sealed electrical connector of the "plug through" type. Furthermore, the pin receiving receptacle of the socket member has a split socket section structurally supported on an enlarged tubular section limiting the use of the socket member to large diameter electric cables in a "plug through" seal arrangement. The present invention seeks to provide an improved female electrical terminal. According to an aspect of the present invention, there is provided a female electrical terminal of one-piece construction as specified in claim 1. The invention may provide an electrical terminal of one-piece construction which can be attached to an electric cable for use in a sealed electrical connector of the "plug through" type. Preferably, the terminal includes compliant contacts which have an increased dimensional tolerance to achieve a desired contact force range, low contact stress to avoid problems of stress relaxation and considerable tolerance for misalignment of the mating pin terminal. Advantageously, the compliant contacts are protected inside a round, protrusion-free cylindrically shaped socket which facilitates the terminal being pushed through a tight hole of a seal without damaging the seal. Preferably, the socket is cylindrically shaped and includes a guide which is easy to form. In an embodiment, the socket does not have any enlargements or sharp edges which would inhibit use of the terminal in a sealed electrical connector of the "plug through" type. Advantageously, the contacts are formed from preplated stock having a band of plating exposed to facilitate quality control and inspection. An embodiment of the present invention is described below, by way of illustration only, with reference to the accompanying drawings, in which: Figure 1 is a plan view of a flat blank for making an embodiment of electrical female terminal of one piece construction; Figure 2 is a side elevational view of an electrical female terminal formed from the flat blank of Figure 1; Figure 3 is an end elevational view in partial cross-section of the electrical female terminal of Figure 2; Figure 4 is a cross-sectional view of the electrical female terminal of Figure 2 taken along line 4-4 of Figure 3; Figure 5 is a cross-sectional view of the electrical female terminal of Figure 2 taken along line 5-5 of Figure 3; and Figure 6 is a perspective view of the electrical female terminal of Figure 2, in partial cross-section to show internal detail. For the purposes of this description, the term "rearward" when used in connection with the electrical female terminal refers to a position adjacent or towards the cable end of the terminal, while the term "forward" refers to a position adjacent or towards the end 24 of the terminal which receives a male terminal. Referring to Figure 1, a flat metal blank for making an electrical female terminal comprises a forward contact portion A which includes a generally rectangular part B which in use is rolled to form a split and cylindrically shaped socket. The forward contact portion A also includes two strips C attached to opposite longitudinal edges of the rectangular part B by short narrow tabs D located near a rearward, cable end of rectangular part B. The strips C are bent to form two longitudinal contact arms inside the socket formed when the rectangular part B is rolled. The blank also includes a rearward winged part E which in use is formed into crimp wings for securing the terminal to an electric cable. The blank is made of a suitably conductive material, preferably a soft copper alloy. If desired, the blank portions B′ of rectangular part B and blank portions C′ of strips C may be readily plated before the blank is formed with a highly electrically conductive material such as gold. As the plating is exposed after the forming process, quality control and inspection of the plating is facilitated. Referring to Figures 2 to 6, an electrical female terminal 10 of one-piece construction is made from the flat blank shown in Figure 1 and comprises a contact portion 12 at one end thereof and an attachment portion 14 at the opposite end thereof to secure the terminal to an electric cable 15, best shown in Figure 2. The contact portion 12 includes a split and cylindrically shaped socket 16 attached to crimp wings 18 of the attachment portion 14 by an intermediate split and cylindrically shaped neck 20 of reduced diameter. The socket 16 has a pair of longitudinal edges 21 that form the longitudinal split 22 when the socket 16 is rolled into a cylinder from the generally rectangular part A of the flat blank shown in Figure 1. The socket 16 also has an annular and inwardly curled lip 24 at its front end which forms an entrance for plugging a mating terminal pin (not shown) into the socket 16. The contact portion 12 further includes a pair of longitudinal contact arms 26 formed from the strips C and disposed inside the socket 16. The contact arms 26 are integrally attached to respective longitudinal edges 21 of the socket 16 by short support tabs 27. The support tabs 27 are located near the rearward, cable end of the socket 16 and are formed by bending the short, narrow blank tabs inwardly as the socket 16 is being formed. The longitudinal contact arms 26 are generally diamond shaped, as best shown in Figure 4, and comprise rearward, cable end, plates 28 attached to respective inwardly bent support tabs 27. The rearward plates 28 are juxtaposed and preferably abut each other. Each rearward plate 28 has a perpendicular, semi-circular flange 30 at its rearward, cable end which engages the inside surface of the socket 16 rearwardly of the support tabs 27. This tab, plate and flange arrangement provides a solid anchor for the longitudinal contact arms 26 extending forwardly in cantilevered fashion. The longitudinal contact arms 26 also include medial diverging portions 32 of arcuate cross-section partially formed out of the rearward, cable end, plates 28. These medial diverging portions 32 preferably engage the inside surface of the socket 16 forwardly of the support tabs 28, best shown in Figures 4 and 6. This provides further support for deflectable contact fingers 34 provided by forward converging portions of the longitudinal contact arms 26, which are also of arcuate cross-section. These deflectable contact fingers 34 biasingly engage opposite sides of a mating pin terminal (not shown) when inserted into the socket 16 through the entrance formed by the inwardly curled lip 24. The tips of the deflectable contact fingers 34 are flared outwardly to guide the pin terminal into the space between the deflectable contact fingers 34. The electrical female terminal 10 can provide a relatively inexpensive terminal of one-piece construction having compliant contacts in a configuration suited for use in a sealed electrical connector of the "plug through" type. The inwardly facing surfaces 35 of the contact fingers 34 may also be readily plated with gold or other highly electrically conductive material.

Claims: A female electrical terminal of one-piece construction comprising a contact portion (12) at a first end of the terminal; an attachment portion (14) at a second end of the terminal for use in attaching the terminal to an electric cable (15); the contact portion including a split socket (16) which comprises first and second adjacent edges (21) extending in an axial direction of the socket and defining said split and an entrance (24) at an end of the socket remote from the attachment portion for enabling a mating terminal pin to be inserted into the split socket, first and second contact arms (26) disposed in the split socket extending in the axial direction of the socket and attached respectively to the first and second edges of the split socket by support tabs (27) located remote from the entrance, the contact arms extending from the support tabs towards the entrance in a cantilevered manner and including medial portions (32) diverging in a direction towards the entrance and converging portions (35) providing deflectable contact fingers (34) adjacent the entrance and adapted to engage a terminal pin. A female electrical terminal according to claim 1, comprising anchor means (27,28,30) anchoring an end of the contact arms (26) remote from the entrance (24). A female electrical terminal according to claim 2, wherein the anchor means comprises first and second abutting plates (28) remote from the entrance (24), each plate being connected to a support tab (27) and including a substantially semi-circular flange (30) disposed between the support tabs and the attachment portion (14) and which abuts an internal surface of the socket. A female electrical terminal according to claim 1, 2 or 3, wherein the contact portion (12) is connected to the attachment portion by an intermediate neck (20) of reduced diameter. A female electrical terminal according to any preceding claim, wherein the medial portions (32) abut an internal surface of the split socket. A female electrical terminal according to any preceding claim, wherein in a direction substantially perpendicular to the axial direction of the split socket, the contact fingers are substantially arcuate in cross-section. A female electrical terminal according to any preceding claim, wherein the entrance includes a curled annular lip (24). A female electrical terminal according to any preceding claim, wherein opposing surfaces of the contact fingers (34) are plated with a highly electrically conductive material.

Inventors: WYMELENBERG MARK JOHN VANDEN, WYMELENBERG, MARK JOHN VANDEN
Applicants: GEN MOTORS CORP, GENERAL MOTORS CORPORATION
Application year: 1993
Main classification: H01R13
IPC codes: H01R13