Miniature Electrical Receptacle Contacts

Abstract

A miniature electrical receptacle contact (8) integrally formed from a single piece of conductive material configured for plugging connection in a linear axial plugging direction with a complementary pin contact having a diameter of less than 2 mm, the receptacle contact including a plugging end section (14) including a contact insertion cavity (18), a rim (26) positioned at an entry end of the receptacle contact and extending completely around the contact insertion cavity, and a contact beam (16) formed from the plugging end section (14) in a cantilevered manner by a slot (20) having an axial portion (34) and a transverse portion (36). The contact beam (16) is attached to the rim (26) proximal to an entry face of the receptacle contact and extends distally from the rim to a free end formed by the transverse portion (36) of the slot (20).

Description

[Technical Field]

[0001] The present invention relates to miniature electrical receptacle contacts for mating with complementary pin contacts, the receptacle contacts being machined from solid electrical conductors. The present invention particularly relates to miniature electrical contacts in which the receptacle contacts have pin-receiving cavity diameters of less than 2 mm to about 0.1 mm. [Background technology]

[0002] It is known to provide miniature receptacle contacts machined from solid metal bodies for high current density applications. In high current density applications, or when reliability and safety are key requirements, contacts machined from a solid piece of material formed as an integral contact are preferred over contacts that include stamped and formed components assembled to the contact body. This is because contacts machined from a solid piece of material offer lower resistance to current flow between the contact section and the cable section of the contact compared to assembled terminals having stamped and formed contact sections. Figures 1a and 1b show a conventional receptacle contact machined from a solid piece of conductive material, such as a copper-based alloy, pluggably coupled to a pin contact. The receptacle contact 8' extends between a wire end section 10' and a bayonet end section 14'. The bayonet end section 14' includes a contact beam 16' with a contact section 30' at the free end of the beam adjacent to the entrance section 22' of the receptacle contact. The receptacle contact 8' has a contact insertion cavity 18' for pluggably receiving the pin contact 6. To fabricate the receptacle contact 8', the contact cavity is first bored with a milling or drilling tool, and then a slot 20' is cut, forming a beam 16' having a transverse portion 36' and an axial portion 34'. The transverse portion 36' is cut proximal to the entry face 24' of the receptacle contact 16', and the beam is fixed axially distal from the entry face 24'. Because the diameter of the bore must be slightly larger than the diameter D3 of the pin contact to be inserted therein, a forming operation is required to plastically deform the end of the contact beam 16' inward so that it protrudes inward into the pin-receiving cavity.

[0003] However, forming operations require relatively complex manufacturing operations, especially for small contacts, where the pin contact diameter ranges from 0.1 to 2 mm and the receptacle body outer diameter is typically less than 3 to 4 mm. These complex operations include registering the receptacle contact's position after the cutting operation on the forming machine and applying a precise amount of plastic deformation, which is difficult to control because it is sensitive to variations in material properties and manufacturing tolerances. The variability of the contact beam's elastic properties after the forming process means that a larger safety margin is required in applications involving high current densities and strict safety specifications. Summary of the Invention [Problem to be solved by the invention]

[0004] SUMMARY OF THE INVENTION In view of the above, it is an object of the present invention to provide a miniature electrical receptacle contact that can handle high current densities in a reliable manner.

[0005] It would be advantageous to provide a miniature electrical receptacle contact that is economical to manufacture.

[0006] It would be advantageous to provide a robust miniature electrical receptacle contact.

[0007] It would be advantageous to provide a miniature receptacle contact that generates a low mating insertion force when complementary male contacts are made. [Means for solving the problem]

[0008] The object of the present invention has been achieved by providing a system as claimed in claim 1. The dependent claims set out various advantageous features of embodiments of the invention.

[0009] Disclosed herein is a miniature electrical receptacle contact integrally formed from a single piece of conductive material configured for plugging connection in a linear axial plugging direction with a complementary pin contact having a diameter of less than 2 mm, the receptacle contact including a plugging end section including a contact insertion cavity, a rim located at an entry end of the receptacle contact and extending completely around the contact insertion cavity, and a contact beam formed from the plugging end section in a cantilevered manner by a slot having an axial portion and a transverse portion, the contact beam attached to the rim proximal to an entry face of the receptacle contact and extending distally from the rim to a free end formed by the transverse portion of the slot.

[0010] In an advantageous embodiment, the contact insertion cavity is milled or drilled and includes an entrance section having a diameter D1 and a contact section having a diameter D2 smaller than the entrance section diameter D1, the entrance section being connected to the contact section via a tapered or chamfered portion, the intersection between the chamfered portion and the contact portion forming the contact point between the contact beam and the complementary pin contact.

[0011] In an advantageous embodiment, the slots are manufactured by subtractive manufacturing techniques.

[0012] In an advantageous embodiment, the slot is machined with a cutting tool.

[0013] In an advantageous embodiment, the axial length L2 of the contact beam from the rim to the contact point is in the range of 1.5 to 4 times the diameter D2 of the contact section.

[0014] In an advantageous embodiment, the rim has an axial length L1, the axial direction being in the direction of the axis of the contact insertion cavity, the axial length L1 being in the range of 0.5 to 1.5 times the diameter D2 of the contact section.

[0015] In an advantageous embodiment, the contact insertion cavity has an overall length L3 that is greater than the combined length of the transverse portion of the slot, the contact beam and the rim, and the contact insertion cavity extends into the central body portion of the receptacle contact.

[0016] In one embodiment, the maximum outer diameter D4 of the receptacle contacts is less than 4 mm.

[0017] In one embodiment, the maximum outer diameter D4 of the receptacle contacts is less than 3 mm.

[0018] In one embodiment, the diameter D2 of the contact section is less than 1.5 mm.

[0019] In one embodiment, the diameter D2 of the contact section is less than 1 mm.

[0020] Also disclosed herein is an electrical receptacle contact combined with an electrical pin contact, the pin contact having a contact portion with a diameter D3 that is larger than the diameter D2 of the contact section and smaller than the diameter D1 of the inlet section.

[0021] In an advantageous embodiment, the contact cavity length L3 is more than twice, preferably more than three times, the beam length to the contact point L2.

[0022] Also disclosed herein is an electrical connector including an insulating housing having a contact-receiving cavity therein, and a plurality of electrical receptacle contacts according to any one of the preceding claims housed within the contact-receiving cavity.

[0023] In one embodiment, the plurality of receptacle contacts has a contact density of greater than 8 contacts per square centimeter when viewed in cross section perpendicular to the insertion direction.

[0024] Further objects and advantageous features of the present invention will become apparent from the appended claims, detailed description and accompanying drawings. [Brief explanation of the drawings]

[0025] [Figure 1a] A perspective view of a prior art small receptacle contact machined from a single piece of conductive material that is connectable to be inserted into a pin contact. [Figure 1b] A side partial cross-sectional view of the prior art contact structure of FIG. 1a. [Figure 2a] A perspective view of a small receptacle contact according to an embodiment of the present invention. [Figure 2b] A side partial cross-sectional view of the receptacle contact of FIG. 2a. [Figure 2c] A detailed portion of the contact section of the receptacle contact of FIG. 2b. [Figure 3a] A perspective view of an electrical connector structure including a male connector and a female connector that are connectable by insertion, wherein the female connector includes an electrical receptacle contact according to an embodiment of the present invention. [Figure 3b] A cross-sectional side view of the connector structure of FIG. 3a is shown. [Figure 4a] Shows the insertion of a male pin contact into a receptacle contact according to an embodiment of the present invention, with the contact section shown in cross-section. [Figure 4b] Shows the insertion of a male pin contact into a receptacle contact according to an embodiment of the present invention, with the contact section shown in cross-section. [Figure 4c] Shows the insertion of a male pin contact into a receptacle contact according to an embodiment of the present invention, with the contact section shown in cross-section. [Figure 4d] A perspective view of a pin contact fitted to a receptacle contact according to an embodiment of the present invention is shown.

MODE FOR CARRYING OUT THE INVENTION

[0026] Next, referring to FIGS. 2a to 4d, an embodiment of a receptacle contact according to an embodiment of the present invention will be described.

[0027] Referring initially to Figures 3a and 3b, an electrical connector structure includes a female connector 1 and a male connector 2 pluggably connected to each other. The female connector 1 includes a housing 3 and a plurality of electrical receptacle contacts 8 mounted in contact-receiving cavities 4 within the housing 3. The diameter or size of the connector structure depends on the number of contacts and the voltage and current requirements, thereby making it generally desirable in many applications to have a connector that is compact without reducing required reliability or performance requirements. High density and high reliability and safety requirements are found, for example, in medical applications and various other sensing and information transmission applications, such as aviation. The miniature contacts of the present invention typically have an outer diameter of less than 3 mm, often less than 2 mm, for example, in the range of 0.5 to 2.5 mm. The resistance to electrical current of the miniature contacts of the present invention is typically less than 0.005 ohms, thereby allowing for higher current densities to be carried compared to conventional contacts of comparable size having fabricated, stamped, and formed contact portions.

[0028] Connectors including multiple miniature contacts according to embodiments of the present invention can have a contact density (viewed in cross section perpendicular to the insertion direction) of, for example, more than 3 contacts per square centimeter, for example, 8 to 16 contacts per square centimeter.

[0029] In applications where a large number of contacts are required, e.g., more than eight contacts, the mating insertion force of the male and female connectors is also an important consideration, such that the insertion force of the individual mating pin and receptacle contacts becomes a significant factor in the overall mating force. As explained in more detail below, the mating force of pin contacts inserted into receptacle contacts according to embodiments of the present invention is lower than the prior art shown in Figures 1a and 1b for comparable performance, i.e., rated current that can flow through contacts of comparable dimensions.

[0030] The electrical receptacle contact 8 includes a wire end section 10 for connection to an external conductor, which in this example is configured to connect to a conductor wire. However, the wire end section 10 may be configured to connect to a circuit board or may have a bayonet-type connection, such as a receptacle or pin contact section, for further connection to a complementary electrical terminal. The electrical receptacle contact 8 extends from the wire end section 10 to a bayonet end section 14 configured for bayonet connection with a complementary pin contact 6. For receptacle contacts having an overall length much longer than the overall diameter of the receptacle contact, the center body section 12 may have a length tailored to the desired overall length of the receptacle contact.

[0031] The receptacle contacts are formed from a single, integral piece of conductive material, preferably metal, such as a copper-based alloy, or other material known per se for machined, single-piece contacts. The contacts are typically fabricated from a rod, from which material is removed in lathe, milling, or cutting operations known per se in the art. Various features may be machined into the body of material to locate and secure the receptacle contacts in cavities formed in insulating material, particularly the insulating housing of an electrical connector. The maximum overall diameter of the receptacle contact 8 is shown as diameter D4; for miniature contacts within the scope of the present invention, D4 is less than 4 mm, typically less than 3.5 mm, and may be in the range of 0.5 to 3 mm, e.g., 0.8 to 2 mm.

[0032] The diameter D3 of the contact portion of the mating pin contact 6 is typically in the range of 30-60% of the maximum overall diameter D4 of the receptacle contact. The receptacle bayonet end section includes a contact beam 16 that is attached to a rim 26 at the entry end of the contact and extends rearwardly toward the central body section 12. A contact insertion cavity 18 for receiving the electrical pin contact 6 extends into the bayonet end section 14 over a contact cavity length L3.

[0033] The contact insertion cavity includes an entry section 22 having a diameter D1 slightly larger than a diameter D3 of a pin contact configured to be inserted into the receptacle contact. The contact insertion cavity further includes a contact section 30 having a diameter D2 smaller than the entry section diameter D1 and slightly smaller than the pin contact diameter D3. A tapered or chamfered portion 28 interconnects the entry section 22 to the contact section 30.

[0034] The contact beam 16 is formed from the body of the contact by a slot 20 having an axial portion 34 extending parallel or substantially parallel to a longitudinal axis A corresponding to the bayonet insertion direction of the pin contact in the receptacle contact, and a transverse portion 36 extending transversely through the tubular wall of the bayonet end section until it meets the transverse portion to form the cantilevered contact beam 16.

[0035] The rim 26 has a length L1 sufficient for the structural integrity of the rim to support the resilient forces applied to the cantilevered contact beam 16 during insertion of the pin contact.

[0036] The location of the chamfer or taper 28 may be configured to define a length L2 from the end of the longitudinal slot where contact with the pin must occur. This defines the effective length of the cantilever beam that is subjected to bending stress when the pin is inserted. The remaining length of the cantilever beam may provide a protective or covering function over the contact insertion cavity 18, which may help prevent the contact from snagging or catching on other objects during handling and manufacturing of the contacts.

[0037] An end section 32 of the contact insertion cavity 18 extends beyond the transverse portion 36 of the slot 20 and into the material of the central body section 12 to receive the tip of the pin contact. The end section 32 can act as a guard against excessive bending forces applied to the mated contact and may center the pin contact relative to the contact insertion cavity.

[0038] Advantageously, compared to the prior art machined miniature contacts illustrated in Figures 1a and 1b, miniature contacts according to embodiments of the present invention can be manufactured without requiring any deformation or bending operations on the resilient contact arms 16, thus not only simplifying the manufacturing procedure but also enabling more accurate and repeatable insertion contact forces when inserting the pin contact into the receptacle contact. This is because machining the contact insertion cavity 18 by drilling, milling, or drilling can be performed with very high precision and does not rely on plastic deformation of the contact beam. Furthermore, the contact force can be easily varied as a function of application and requirements by simply varying the diameter D2 of the contact cavity section and / or the length L2 of the entrance section 22, thereby displacing the position of the chamfer 28 that determines the contact point.

[0039] The bayonet insertion force is easier to precisely adjust due to more precise tolerances in the location of the contact point and therefore in the elastic beam strength of the contact beam. In the prior art configuration shown in Figures 1a and 1b, when the contact beam pivots, a small displacement component occurs in the direction opposite to the insertion of the pin, whereas in the configuration of the present invention, when the contact beam rotates, the axial displacement component is essentially zero or sightly in the insertion direction.

[0040] Thus, the insertion force falls within a narrower range of variability than prior art solutions, while ensuring a well-defined contact force and therefore well-defined current-carrying performance.

[0041] [List of references used] Electrical Male Connector 1 Electrical pin contact 6 Electrical female connector 2 Housing 3 Contact receiving cavity 4 Electrical Receptacle Contacts 8 Wiring end section 10 Center body section 12 Plug-in end section 14 Contact beam 16 Rim 26 Contact insertion cavity 18 Entrance Section 22 Entrance 24 Chamfer 28 Contact Section 30 Free end section 32 Slot 20 Axial section 34 Transverse section 36 Contact cavity entrance section diameter D1 Contact cavity contact section diameter D2 Pin contact diameter D3 Receptacle contact body diameter D4 Length of the inlet section to the slot L1 Beam length to contact point L2 Contact cavity length L3 Electrical Receptacle Contact 8' (Prior Art) Wiring end section 10 Center body section 12 14' bayonet end section Contact beam 16' Contact insertion cavity 18' Entrance section 22' Entrance surface 24' Rim 26' Contact section 30' Slot 20' Axial section 34' Transverse section 36'

[0042] [Embodiment] (1) A miniature electrical receptacle contact (8) integrally formed from a single piece of conductive material configured for insertion connection in a linear axial insertion direction with a complementary pin contact having a diameter of less than 2 mm, said receptacle contact including a plug end section (14) including a contact insertion cavity (18), a rim (26) positioned at an entry end of said receptacle contact and extending completely around said contact insertion cavity, and a contact beam (16) formed from said plug end section (14) in a cantilevered manner by a slot (20) having an axial portion (34) and a transverse portion (36); 1. A miniature electrical receptacle contact, wherein the contact beam (16) is attached to the rim (26) proximal to an entry face of the receptacle contact and extends distally from the rim to a free end formed by the transverse portion (36) of the slot (20). (2) The receptacle contact of embodiment 1, wherein the contact insertion cavity (18) includes an entrance section (22) milled or drilled and having a diameter D1, and a contact section (30) having a diameter D2 smaller than the diameter D1 of the entrance section, the entrance section being connected to the contact section via a tapered or chamfered portion (28), and the intersection between the chamfered portion and the contact section forms a contact point between the contact beam and the complementary pin contact (6). (3) A receptacle contact according to any one of the preceding claims, wherein the slot is manufactured by subtractive manufacturing techniques. (4) A receptacle contact according to embodiment 3, wherein the slot (20) is machined with a cutting tool. (5) A receptacle contact according to any one of embodiments 1 to 4, wherein the axial length L2 of the contact beam (16) from the rim (26) to the contact point is in the range of 1.5 to 4 times the diameter D2 of the contact section.

[0043] (6) A receptacle contact according to any one of embodiments 1 to 5, wherein the rim has an axial length L1, the axial direction being in the direction of the axis of the contact insertion cavity, and the axial length L1 is in the range of 0.5 to 1.5 times the diameter D2 of the contact section. (7) A receptacle contact as described in any one of embodiments 1 to 6, wherein the contact insertion cavity (18) has a total length L3 that is longer than the sum of the lengths of the transverse portion of the slot, the contact beam, and the rim, and the contact insertion cavity extends within a central body portion of the receptacle contact. (8) A receptacle contact according to any one of embodiments 1 to 7, wherein the maximum outer diameter D4 of the receptacle contact is less than 4 mm. (9) A receptacle contact according to embodiment 8, wherein the maximum outer diameter D4 of the receptacle contact is less than 3 mm. (10) A receptacle contact according to any one of embodiments 1 to 9, wherein the diameter D2 of the contact section is less than 1.5 mm.

[0044] (11) A receptacle contact according to embodiment 10, wherein the diameter D2 of the contact section is less than 1 mm. (12) An electrical receptacle contact (8) as described in any one of embodiments 1 to 11, in combination with an electrical pin contact (6), the pin contact having a contact portion with a diameter D3 that is larger than the diameter D2 of the contact section and smaller than the diameter D1 of the inlet section. (13) A receptacle contact according to any one of embodiments 1 to 12, wherein the length L3 of the contact cavity is more than twice, preferably more than three times, the beam length L2 to the contact point. (14) An electrical connector (2) comprising an insulating housing (3) having a contact-receiving cavity (4) therein, and a plurality of electrical receptacle contacts according to any one of claims 1 to 13 housed within the contact-receiving cavity. (15) An electrical connector as described in embodiment 14, wherein the plurality of receptacle contacts have a contact density of greater than 8 contacts per square centimeter when viewed in a cross section perpendicular to the insertion direction.

Claims

1. 1. A miniature electrical receptacle contact (8) integrally formed from a single piece of conductive material configured for plugging connection in a linear axial plugging direction with a complementary pin contact having a diameter of less than 2 mm, said receptacle contact including a plugging end section (14) including a contact insertion cavity (18), a rim (26) positioned at an entry end of said receptacle contact and extending completely around said contact insertion cavity, and a contact beam (16) formed from said plugging end section (14) in a cantilevered manner by a slot (20) having an axial portion (34) and a transverse portion (36); 1. A miniature electrical receptacle contact, wherein the contact beam (16) is attached to the rim (26) proximal to an entry face of the receptacle contact and extends distally from the rim to a free end formed by the transverse portion (36) of the slot (20).

2. 2. The receptacle contact of claim 1, wherein the contact insertion cavity (18) is milled or drilled and includes an entrance section (22) having a diameter D1 and a contact section (30) having a diameter D2 smaller than the entrance section diameter D1, the entrance section being connected to the contact section via a tapered or chamfered portion (28), the intersection between the chamfered portion and the contact portion forming the contact point between the contact beam and the complementary pin contact (6).

3. 10. The receptacle contact of claim 1, wherein the slot is manufactured by subtractive manufacturing techniques.

4. 4. The receptacle contact of claim 3, wherein the slot (20) is machined with a cutting tool.

5. The receptacle contact of claim 1, wherein the axial length L2 of the contact beam (16) from the rim (26) to the contact point is in the range of 1.5 to 4 times the diameter D2 of the contact section.

6. 2. The receptacle contact of claim 1, wherein the rim has an axial length L1, the axial direction being in the direction of an axis of the contact insertion cavity, and the axial length L1 being in the range of 0.5 to 1.5 times the diameter D2 of the contact section.

7. 2. The receptacle contact of claim 1, wherein the contact insertion cavity has an overall length L3 that is greater than the sum of the lengths of the transverse portion of the slot, the contact beam, and the rim, and the contact insertion cavity extends within a central body portion of the receptacle contact.

8. The receptacle contact according to claim 1 , wherein the maximum outer diameter D4 of the receptacle contact is less than 4 mm.

9. The receptacle contact according to claim 8 , wherein the maximum outer diameter D4 of the receptacle contact is less than 3 mm.

10. The receptacle contact of claim 1 , wherein the contact section has a diameter D2 of less than 1.5 mm.

11. The receptacle contact of claim 10, wherein the diameter D2 of the contact section is less than 1 mm.

12. 2. The electrical receptacle contact (8) of claim 1, in combination with an electrical pin contact (6), the pin contact having a contact portion with a diameter D3 that is larger than the diameter D2 of the contact section and smaller than the diameter D1 of the inlet section.

13. 2. The receptacle contact of claim 1, wherein the length L3 of the contact cavity is more than twice, preferably more than three times, the length L2 of the beam to the contact point.

14. 10. An electrical connector (2) comprising: an insulating housing (3) having a contact-receiving cavity (4) therein; and a plurality of electrical receptacle contacts according to claim 1 disposed within said contact-receiving cavity.

15. 15. The electrical connector of claim 14, wherein the plurality of receptacle contacts have a contact density, when viewed in cross section perpendicular to the insertion direction, of greater than eight contacts per square centimeter.

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