ELECTRICAL CONTACT TERMINAL AND METHOD TO MANUFACTURE THE SAME

Abstract

An electrical contact terminal formed of sheet metal, an electrical connector comprising the terminal, and a method to manufacture the terminal is presented. The terminal includes a longitudinally extending cavity for receiving an electrical contact pin therein and a contact beam having a contact face arranged at least partially inside the cavity. The contact beam is configured to be deflected by the electrical contact pin to apply a contact force to the contact pin when the electrical contact pin is received in the cavity. The terminal further includes a flat support wall oriented substantially parallel to the insertion direction of the electrical contact pin. An aperture is formed proximate to an edge of the support wall to form a support spring element in the support wall. The support spring element is configured to engage with the contact beam when the same is deflected, thereby increasing contact force.

Claims

1. An electrical contact terminal, comprising: a longitudinally extending cavity for receiving an electrical contact pin therein; a contact beam, having a contact face arranged at least partially inside the cavity, wherein the contact beam is configured to be deflected by the electrical contact pin to apply a contact force to the electrical contact pin when the electrical contact pin is received in the cavity, and a flat support wall oriented substantially parallel to an insertion direction of the electrical contact pin into the cavity, wherein an aperture is formed proximate to an edge of the flat support wall to form a support spring element in the flat support wall and wherein the support spring element is configured to engage with the contact beam when the support spring element is deflected, thereby increasing the contact force.

2. The electrical contact terminal according to claim 1, wherein the contact beam is configured to be deflected by the electrical contact pin in a deflection plane and wherein the flat support wall is oriented parallel to the deflection plane.

3. The electrical contact terminal according to claim 1, wherein the aperture comprises an essentially closed rim to form the support spring element and wherein the support spring element is a single support spring arm configured to engage with the contact beam, thereby increasing the contact force.

4. The electrical contact terminal according to claim 1, wherein the aperture comprises an open rim to form a spring element and wherein the support spring element comprises a primary support spring arm and a secondary support spring arm, wherein the primary support spring arm and/or the secondary support spring arm are configured to engage with the contact beam, thereby increasing the contact force.

5. The electrical contact terminal according to claim 4, wherein the primary support spring arm and the secondary support spring arm have different lengths and wherein the primary support spring arm, arranged farther form a pin insertion opening of the electrical contact terminal, is longer than the secondary support spring arm, arranged closer to the pin insertion opening of the electrical contact terminal.

6. The electrical contact terminal according to claim 4, wherein the primary support spring arm and the secondary support spring arm have different lengths, and wherein one support spring arm is at least twice as long as the other support spring arm.

7. The electrical contact terminal according to claim 4, wherein the primary support spring arm and the secondary support spring arm are arranged such that the primary support spring arm is configured to first engage with a corresponding contact beam and the secondary support spring arm is configured to engage subsequently with the corresponding contact beam during insertion of the electrical contact pin into the cavity.

8. The electrical contact terminal according to claim 1, wherein the aperture has a substantially elliptical shape.

9. The electrical contact terminal according to claim 1, wherein the contact beam comprises an engaging face, wherein the support spring element is configured to engage with the engaging face of the contact beam to increase the contact force, and wherein the engaging face is preferably arranged opposite to the contact face of the contact beam.

10. The electrical contact terminal according to claim 1, wherein the support spring element and the contact beam extend along the insertion direction of the electrical contact pin into the cavity and wherein the support spring element is arranged symmetrical to the contact beam.

11. The electrical contact terminal according to claim 1, wherein the geometrical shape of the support spring element is designed to provide the contact force of at least 1 N.

12. The electrical contact terminal according to claim 1, wherein the electrical contact terminal has a width of at most 1.8 mm and a height of at most 2.3 mm.

13. The electrical contact terminal according to claim 1, wherein the electrical contact terminal is formed from a metal sheet having a thickness of at most 0.2 mm and wherein the electrical contact terminal is preferably integrally formed as one part.

14. The electrical contact terminal according to claim 1, wherein the electrical contact terminal comprises a further contact portion being integrally formed with an inner wall of the cavity which further contact portion protrudes into the cavity and is configured to contact an opposite side of the electrical contact pin as contacted by the contact beam, when the electrical contact pin is received in the cavity.

15. An electrical connector assembly, comprising: a connector housing, and an electrical contact terminal according to claim 1.

16. A method to manufacture an electrical contact terminal, comprising the steps of: cutting a preform from a metal sheet, wherein the cutting is performed with a stamping tool, wherein the preform comprises a preform of a contact beam, a preform of a flat support wall, and a preform of a terminal body, wherein an aperture is formed proximate to an edge of the flat support wall to build a support spring element and wherein the preforms are preferably integrally formed, and bending the preforms to form: a longitudinally extending cavity for receiving an electrical contact pin therein; the contact beam having a contact face arranged at least partially inside the cavity, wherein the contact beam is configured to be deflected by the electrical contact pin to apply a contact force to the electrical contact pin when the electrical contact pin is received in the cavity, and a support side wall oriented substantially parallel to an insertion direction of the electrical contact pin into the cavity, wherein the support spring element is configured to engage with the contact beam when the support spring element is deflected, thereby increasing the contact force.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

[0052] The present invention will now be described, by way of example with reference to the accompanying drawings, in which:

[0053] FIG. 1 illustrates a schematic cut view of an electrical contact terminal, according to the prior art;

[0054] FIG. 2A illustrates a schematic perspective view of an electrical contact terminal according to one embodiment;

[0055] FIG. 2B illustrates a schematic cut view of an electrical contact terminal according to one embodiment;

[0056] FIG. 2C illustrates a schematic partially cut view of an electrical contact terminal according to one embodiment;

[0057] FIG. 3 illustrates a schematic cut view of an electrical contact terminal according to another embodiment; and

[0058] FIG. 4 illustrates a schematic insertion force/insertion path diagram of the electrical contact terminal of FIGS. 2A-2C.

DETAILED DESCRIPTION OF THE INVENTION

[0059] In particular, FIG. 1 shows an electrical contact terminal 100 according to the prior art. In these known electrical contact terminals 100, an electrical contact pin 110 can be inserted into the electrical contact terminal 100 along an insertion direction A, indicated by arrow A. Upon insertion, the electrical contact pin 110 will come into contact with the contact beam 120. The contact beam 120 comprises a spring portion 122 and a contact face 124. The contact face 124 contacts the electrical contact pin 110 to establish an electrical contact and to apply a contact force F.sub.N onto the electrical contact pin 110. Upon insertion of the electrical contact pin 110, the spring portion 122 of the contact beam 120 is deflected. In order to increase the contact force that is achievable, a support beam 142 is provided. The support beam 142 is a portion of the electrical contact terminal and e.g. integrally formed therewith. The support beam 142 comprises an engaging face 144 for engaging with the electrical contact beam 120. When the contact beam 120 is deflected, it engages with the engaging face 144 of the support beam 142, resulting in an increased contact force on the electrical contact pin 110. As can be seen from FIG. 1, the contact beam 120 as well as the support beam 142 are arranged in a stacked manner, wherein their thickness corresponds to the sheet thickness of the electrical contact terminal 100. Thus, the achievable contact force F.sub.N is limited by the maximum sheet thickness. Further, due to the design of the support beam 142, so terminals tend to be very stiff and therefore vary in the achievable contact force depending on the dimensional tolerances of the inserted electrical contact pin 110.

[0060] FIGS. 2A-2C show an embodiment of an electrical contact terminal 200 that is provided with a support spring element 240, comprising an aperture 252 having an open rim. In the respective figures, same reference signs are used for same parts.

[0061] FIG. 2A shows a schematic perspective view of an electrical contact terminal 200. The terminal has a width w of approximately 1 mm to 1.8 mm and a height h of approximately 1.5 mm to 2.3 mm. The sheet thickness d is preferably in the range of at most 0.2 mm to at most 0.15 mm. The electrical contact terminal 200 is preferably formed from an integrally formed pre-form being cut from a metal sheet. The cutting is preferably performed with a stamping tool. After cutting, the pre-form is bent to the shape shown in FIG. 2A building an electrical contact terminal 200.

[0062] The electrical contact terminal 200 comprises a pin-receiving cavity 232 that is restricted by a bottom wall 266 and an opposite top wall 268. Laterally, the pin-receiving cavity 232 is restricted by a first side wall 262 and a second side wall 264. The second side wall 264 extends over the top wall 268 and is connected via a support top wall 268 with the flat support wall 250. The top wall 268 is connected with a contact beam 220 as best shown in FIGS. 2B and 2C.

[0063] In the flat support wall 250, an aperture 252 is formed in proximity to an edge of the flat support wall 250, which edge has a convex curved shape. Thus, a support spring element 240 is formed. Since the aperture 252 comprises an open rim, the support spring element 240 is divided by gap 254 into two support spring arms 242, 246. The support spring arm 242, which is a primary support spring arm 242, is longer than the support spring arm 246, which is a secondary support spring arm 246.

[0064] The electrical contact terminal 200 allows providing increased contact forces, while the terminal body 230, respectively the electrical contact terminal 200, is less stiff and stress-optimized, so that tolerances of the dimensions of the electrical contact pin 210 that can be inserted into the pin-receiving cavity 232 will not lead to significantly varying contact and pin insertion forces.

[0065] FIG. 2B shows a schematically cut view of the electrical contact terminal 200 of FIG. 2A. FIG. 2B further shows an electrical contact pin 210 that is inserted into the pin-receiving cavity 232 in order to establish an electrical contact between the electrical contact terminal 200 and the electrical contact pin 210. Upon insertion, the electrical contact pin 210 will come into contact with a contact face 224 of a contact beam 220. The contact beam 220 comprises a spring portion 222 that interconnects the top wall 268 with the contact face 224. Due to the spring portion 222, the contact beam 220 is deflectable and can apply a contact force onto the electrical contact pin 210. Parallel to the insertion direction A, a flat support wall 250 is arranged. The flat support wall 250 comprises an aperture 252, being formed in the flat support wall 250 in proximity to an edge of the flat support wall 250, thereby forming a support spring element 240. Since the aperture 252 comprises an open rim, the support spring element 240 is divided via gap 254 into two support spring arms 242, 246, i.e. a primary support spring arm 242 and a secondary support spring arm 246.

[0066] The primary support spring arm 242 is arranged farther from the pin insertion opening of the electrical contact terminal 200 and is longer than the secondary support spring arm 246. Preferably, the primary support spring arm 242 is at least twice as long, even more preferably at least three times as long and even more preferably at least five times as long as the secondary support spring arm 246. Upon insertion of the electrical contact pin 210, the electrical contact pin 210 will in a first insertion phase I, contact the contact beam 220 at the contact face 224 and deflect the contact beam 220. Then, the contact beam 220 engages in a second insertion phase II with the primary support spring arm 242 at a primary support face 244. Preferably, the engagement occurs at an engaging face 226 of the contact beam 220. Due to the engagement, the primary support spring arm 242 is deflected and the contact force onto the electrical contact pin 210 is increased. In a third insertion phase III, the contact beam 220 is further deflected, so as to engage with the secondary support spring arm 246 to further increase the contact force. The secondary support spring arm 246 comprises a support face 248 to engage with the engaging face 226 of the contact beam 220. The contact force applied onto the electrical contact pin during the insertion phases I, II and III is discussed in greater detail with reference to FIG. 4.

[0067] FIG. 2C shows a partially cut view of an electrical contact terminal 200, wherein a further contact portion 270 is provided integrally formed with the bottom wall 266 of the electrical contact terminal 200. The reference signs used in FIG. 2C correspond to the reference signs used in FIGS. 2A and 2B. The further contact portion 270 comprises a contact face 275 that will contact an electrical contact pin 210 at a position opposite to the position, where the contact face 224 of the electrical contact pin 210 contacts the electrical contact pin 210 upon insertion. With providing a further contact portion 270, the contact force can be further increased. Further, the engaging face 226 for engaging the contact beam 220 with the primary and secondary support spring arms 242, 246 is arranged opposite to the contact face 224. Thus, the contact force that is applied onto the electrical contact pin 210 can be transferred directly to the support spring arms 242, 246 and further to the flat support wall 250.

[0068] FIG. 3 shows a schematic cut view of a further embodiment of an electrical contact terminal 300. The design and shape of the electrical contact terminal 300 corresponds in particular to the design and shape of the electrical contact terminal 200 described with respect to FIGS. 2A-2C. However, the embodiment shown in FIG. 3 distinguishes from the embodiment shown in FIGS. 2A-2C in that the aperture 352 formed in the flat support side wall 350 comprises a closed rim. In detail:

[0069] The electrical contact terminal 300 comprises a pin insertion cavity 332 that is configured to receive an electrical contact pin 310 in the pin insertion direction A. Upon insertion, the electrical contact pin 310 will contact a contact beam 320 at a contact face 324. The contact beam 320 comprises a spring portion 322 to apply a contact force F.sub.N onto the electrical contact pin 310. The spring portion 322 interconnects the contact face 324 with a top wall 368 of the pin insertion cavity 332. The top wall 368 lays opposite to a bottom wall 366. Further, a flat support side wall 350 is provided that is arranged substantially parallel to the pin insertion direction A.

[0070] Further, an aperture 352, having a closed rim, is formed in proximity to an edge of the flat support side wall 350 to form a support spring element 340. The support spring element 340 comprises a single support spring arm 342 that is connected with the support spring wall 350 at two points and functions similarly to a leaf spring. The support spring arm 342 is provided with a support face 344 that engages with an engaging face 326 of the contact beam 320, when the contact beam 320 is deflected. Thus, the contact force applied via the contact beam 320 onto the electrical contact pin 310 can be increased. In will be understood that in the embodiments shown in FIGS. 2A-3, the contact beams 220, 320 can engage with the respective support spring elements 240, 340, respectively the support spring arms 242, 246, 342, even before inserting the electrical contact pin 210, 310 into the cavity, i.e. before the contact beams 220, 320 are deflected.

[0071] FIG. 4 shows a schematic contact force/insertion path diagram of an electrical contact terminal, such as electrical contact terminal 200. The insertion path x corresponds to the insertion depth of an electrical contact pin 210 into an electrical contact terminal 200, as shown in FIGS. 2A to 2C. The contact force F.sub.N corresponds to the normal force applied via the contact beam 220 and/or the support spring arm(s) 242, 246 onto the electrical contact pin 210. In a first insertion phase I, the electrical contact pin 210 contacts the contact beam 220, wherein the contact beam 220 is not yet in contact with a support spring arm 242, 246. With increasing insertion depth, the contact force F.sub.N applied onto the electrical contact pin 210 increases, but would not exceed beyond the contact force level that is achieved at the end of pin insertion phase I.

[0072] At the end of pin insertion phase I, the deflected contact beam 220 engages with the primary support spring arm 242. Due to the engagement, the contact beam 220 and the primary support spring arm 242 are deflected, so that the contact force rises further to a certain level, achieved at the end of insertion phase II. At the end of insertion phase II, the deflected contact beam 220 engages with the secondary support spring arm 246. Thus, the contact force can be further increased. After a certain insertion depth, the contact force remains constant. Thus, the contact force can be gradually increased over the insertion phases I, II, III in order to provide a desired high contact force.

[0073] While this invention has been described in terms of the preferred embodiments thereof, it is not intended to be so limited, but rather only to the extent set forth in the claims that follow. Moreover, the use of the terms first, second, primary secondary, etc. does not denote any order of importance, but rather the terms first, second, etc. are used to distinguish one element from another. Furthermore, the use of the terms a, an, etc. do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced items.