Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
  • H01R13/00—Details of coupling devices of the kinds covered by groups H01R12/70 or H01R24/00 - H01R33/00
  • H01R13/02—Contact members
  • H01R13/22—Contacts for co-operating by abutting
  • H01R13/24—Contacts for co-operating by abutting resilient; resiliently-mounted
  • H01R13/2407—Contacts for co-operating by abutting resilient; resiliently-mounted characterized by the resilient means
  • H01R13/2421—Contacts for co-operating by abutting resilient; resiliently-mounted characterized by the resilient means using coil springs

Definitions

• This invention generally relates to the art of electrical connectors and, particularly, to a electrical terminal for use in electrical connectors, testing probes or the like.
• FIG. 1 shows a conductive electrical terminal, generally designated 20, which can be used in electrical connectors or testing probes, according to the prior art.
• the terminal is an assembly which includes a housing 22, a contact member 24 and a coil spring 26.
• the contact member has a reduced-diameter front end 24a and an enlarged rear end 24b.
• the housing has a bore 22a within which the enlarged rear end of the contact member is slidably disposed.
• the housing also has an open front end 22b and a closed rear end 22c.
• Coil spring 26 is sandwiched and "loaded” between closed rear end 22c of the housing and rear end 24b of the contact member to bias the contact member forwardly as shown in FIG. 1.
• coil spring 26 and contact member 24 are assembled into housing 22 through the front open end of the housing.
• the front end of the housing is reformed by coining, crimping, riveting or other process to form a reduced-diameter hole through which the reduced-diameter front end 24a of contact member 24 protrudes.
• the reduced-diameter front end of the housing thereby, forms a stop to define the forward limit position of the contact member and also to provide a bearing hole through which front end 24a of the contact member is reciprocally slidable.
• the surface area between the housing and the contact member at the reduced-diameter open front end of the housing is the thickness of the metal material of the housing.
• closed rear end 22c of housing 22 may be fixed to a circuit trace on a printed circuit board by surface soldering techniques or by securing the rear end of the housing in a hole in the circuit board.
• the front end of contact member 24 may be used for engaging an appropriate contact of a complementary connecting device, or the front end of the contact member may be used in a testing probe apparatus, both applications providing a terminal for transmitting signals to the circuit board.
• Various problems are encountered with prior art terminals as described above in relation to FIG. 1. In particular, the length of the bearing surfaces between housing 22 and the front end portion 24a of contact member 24 is quite small.
• the length or area of the bearing surfaces is defined by the wall thickness of the housing at open front end 22b thereof. Since the housing typically is stamped and formed of sheet metal material, this thickness is only the thickness of the sheet metal. This very thin thickness does not provide good support for contact member 24, and the contact member can move sideways under side direction forces, resulting in loosening the contact member and even deforming the housing.
• the aperture dimensions of open front end 22b of the housing is difficult to control with the coining, crimping or riveting processes. The aperture often is too big or too small. When the aperture is too big, the contact member again can loosen. When the aperture is too small, resistance occurs to prevent the contact member from easily flexing inwardly against the biasing forces of coil spring 26.
• the present invention is directed to solving these various problems.
• the terminal includes a contact member having a front end portion of a given diameter and an enlarged rear end portion of a diameter at least slightly larger than the given diameter.
• a metal housing has a through hole for slidably receiving the rear end portion of the contact member.
• the through hole defines a longitudinal axis and includes an open rear end through which the contact member can be inserted into the housing.
• the through hole has an open front end through which the front end portion of the contact member extends and is exposed exteriorly of the housing for engaging a complementary contact device.
• the open front end of the through hole is of a reduced diameter to define a stop for abutting the enlarged rear end portion of the contact member to define a forward limit position of the contact member.
• the open front end of the through hole is drawn to define an axially extending neck portion of a controlled diameter for slidably receiving the front end portion of the contact member.
• a biasing member is disposed in the through hole behind the contact member to resihently bias the contact member forwardly.
• the biasing member comprises a spring.
• a base cap is provided for closing the rear end of the through hole in the metal housing to hold the biasing member and the contact member therein.
• the base cap is fabricated of sheet metal material and is crimped about the housing at the open rear end thereof.
• the housing includes an outwardly flared flange about which the base cap is crimped.
• the base cap includes a closure plug inserted into the open rear end of the through hole.
• the housing is fabricated of sheet metal material and is crimped about the closure plug at the open rear end of the hole.
• FIG. 1 is an axial section through the prior art electrical terminal descried in the Background, above;
• FIG. 2 is an exploded perspective view of an electrical terminal according to a first embodiment of the invention;
• FIG. 3 is a perspective view of the terminal of FIG. 2, in assembled condition;
• FIG. 4 is an axial section through the housing and base cap of the terminal of the first embodiment;
• FIGS. 5-7 are views similar to that of FIGS. 2-4, but of a second embodiment of the invention.
• a first embodiment of a conductive terminal according to the invention is generally designated 30.
• the terminal includes a metal housing 32, a contact member 34, a spring 36, and a base cap 38.
• the contact member and the spring are inserted into a through hole 40 (Fig. 4) in housing 32 in the direction of arrow "A" (Fig. 2).
• Base cap 38 then is used to close the rear end of the through hole as described hereinafter.
• the through hole of the housing defines a longitudinal axis 32 (Fig. 2) running lengthwise of the terminal.
• Contact member 34 includes a front end portion 34a of a reduced or given diameter and an enlarged rear end portion 34b of a diameter slightly larger than the diameter of the front end portion.
• the enlarged rear end portion 34b of the contact member is slidably received within through hole 40 of the housing for reciprocation along axis 42.
• Spring 36 is an elongated coil spring which is sandwiched, under compression, between end cap 38 and the enlarged rear end portion 34b of the contact member, as seen clearly in FIG. 4. The coil spring biases the contact member forwardly to the contacting position shown in FIGS. 3 and 4.
• Metal housing 32 may be rolled and fonned of sheet metal material generally in the form of a circular tube and includes an open rear end 32a through which contact member 34 and coil spring 36 can be inserted into through hole 40 of the housing.
• the through hole has an open front end 32b through which the front end portion 34a of the contact member extends and is exposed exteriorly of the housing for engaging a complementary contact device or for acting as a testing probe.
• the bottom of housing 32 has an outwardly flared peripheral flange 32c.
• Base cap 38 may be formed of sheet metal material and includes a disk-shaped closure portion 38a for closing open rear end 32a of the housing.
• the base cap is generally cup-shaped and includes an upstanding peripheral side wall 38b which is circular and which is crimped about the outwardly flared peripheral flange 32c of the housing, as clearly seen in FIG. 4. Once crimped to the housing, base cap 38 holds coil spring 36 and contact member 34 in their assembled condition within through hole 40 of the housing, as seen in FIG. 4.
• the invention contemplates that metal housing 32 be formed with a collar or sleeve at open front end 32b of the housing to define a neck 50 which surrounds front end portion 34a of contact member 34.
• the neck has a length or height as indicated by the arrows at "h".
• the inside surface of neck 50 provides a substantial bearing surface area for engaging and stabilizing front end portion 34a of the contact member.
• FIGS. 5-7 show a second embodiment of the invention which differs from the first embodiment in the configuration of an end cap 38 A. Like reference numerals have been applied to housing 32, contact member 34 and coil spring 36 corresponding to the components described above in relation to the first embodiment of FIGS. 2-4. In order to avoid unduly burdening this specification, the above descriptions of the like components will not be repeated.
• base cap 38A of the second embodiment includes a closure plug 52 which is inserted into the rear open end of through hole 40 of housing 32.
• the closure plug is circular in cross-section, and a peripheral groove 54 is formed at a base of the plug.
• the rear end of housing 32 is crimped into groove 54, as at 56.
• a peripheral notch 58 is formed about the housing above closure plug 52.
• FIGS. 2-7 also includes the neck 50 formed at the open front end 32b of the housing for embracing front end portion 34a of contact member 34.
• the neck in both embodiments of FIGS. 2-7 are shown with a given length or height "h" as described above, it should be understood that the length or height of the neck can be varied or considerably lengthened from that shown in the drawings. This is done quite simply in the fabrication of housing 32 prior to assembling the contact member therewithin. These provisions for adjusting the bearing surface of the housing about the front end portion of the contact member would be impossible with the prior art.
• the invention may be embodied in other specific forms without departing from the spirit or central characteristics thereof. The present examples and embodiments, therefore, are to be considered in all respects as illustrative and not restrictive, and the invention is not to be limited to the details given herein.

Landscapes

• Connector Housings Or Holding Contact Members (AREA)
• Coupling Device And Connection With Printed Circuit (AREA)

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Publications (1)

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Cited By (1)

Families Citing this family (5)

Citations (2)

• 2003
  • 2003-08-12 CN CNU032081243U patent/CN2648626Y/zh not_active Expired - Fee Related
• 2004
  • 2004-08-12 JP JP2006523378A patent/JP2007502520A/ja active Pending
  • 2004-08-12 WO PCT/US2004/026204 patent/WO2005018058A1/en active Application Filing

Patent Citations (2)

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