Rika Electronics International, Inc.

Stephen A Boyle

John C Bergeron

A double-ended, coaxial contact assembly has a center probe rod ( ) mounted in the bore of a dielectric center spacer bushing ( ) and mounts a probe contact assembly on each end of the center probe rod. The center probe rod is received in a ground sleeve ( ) with the probe contact assemblies maintained in coaxial relationship with the ground sleeve by a dielectric outer spacer bushing ( ). In certain embodiments a movable ground plunger ( ) is slidably received in each end of the ground sleeves and biased outwardly by respective ground plunger coil springs ( ). In one such embodiment the center spacer bushing ( &prime;) is provided with an axially extending sleeve disposed between the respective probe contact assembly and the ground sleeve.

Contact apparatus particularly useful with test equipment

A coaxial contact assembly (,) is shown in which the outer cylindrical barrel (,) is adapted to be fixedly mounted in a support and with a ground plunger (,) telescopically and slidably received therein and with an interface ductor member (,) in turn telescopically and slidably received within the bore of the ground plunger. The interface member is fixedly attached to and in electrical engagement with the braid layer of a coaxial cable (,) and is formed with a plurality of elongated, longitudinally extending fingers (,) which extend radially outwardly a selected amount so that when received in the bore of the ground plunger they are biased into intimate electrical engagement therewith. An inverse electrical connection between the ductor member and the ground plunger is shown with fingers (,) of ground plunger (,) biased into electrical engagement with a solid tubular inductor member (,). A dielectric spacer member (,) is mounted on the signal sleeve (,) and prevents electrical shorting between the interface ductor member (,) and the inner contact plunger (,). The inner, or signal, plunger (,) is maintained in coaxial relationship with the ground sleeve by means of a dielectric spacer member (,) mounted on the inner plunger (,). A coil spring (,) is disposed around the interface member for biasing the ground sleeve outwardly.

Electrical contact system

An electrical contact assembly (10) for use, for example, in interfacing between a circuit board or the like to be tested and test apparatus has first and second contact plungers (14,16) which are slidably mounted in an outer barrel (12) with respective contact projections (14c,16c) extending out opposite ends of the barrel. The first contact plunger (14) is hollow and slidably receives therein an elongated longitudinally extending portion (16a) of the second contact plunger (16), the contact plungers being biased apart by a coil spring (18) mounted between respective spring seats (14e,16g) of the contact plungers. Alternate embodiments (10',10') include a plurality of longitudinally extending fingers (14h,16h) formed in one of the plungers which form an interference fit with the other plunger. In another embodiment (10'') the first and second contact plungers (14',16') are interlocked together by means of a decreased diameter portion (14k) in the bore of the first contact plunger and a cooperating enlarged diameter portion (16m) at the distal end of the elongated portion (16a).

Electrical contact assembly for interconnecting test apparatus and the

A coaxial contact assembly (10,10', 10') has a cylindrical ground plunger (30) which is fixedly attached to the ground conductor (1b) of a coaxial cable (1,1') through a ground sleeve (28) and mounted in a test head support (4) for sliding movement therein. An inner contact plunger barrel (18) is fixedly attached to the signal conductor (1a) of the coaxial cable either through a signal sleeve (16) for a replaceable inner contact assembly, or directly for a dedicated unit. An inner contact plunger (20) received in the plunger barrel has a contact portion (20c) biased outwardly to extend a selected amount beyond the ground plunger (30) in a given direction by a first spring member (24) while a second spring (36) biases the ground plunger outwardly in the given direction to a preset location. The spring force of the second spring is greater than that of the first spring so that initially plunger (20) will move inwardly independently of the ground plunger upon engagement with a test site until coplanarity occurs after which both the inner and outer contact portions will move together. Contact assemblies may be joined together through a flexible cable to form a double-ended configuration which can accommodate offset as well as in-line mounting. The ground plunger (30) and inner contact plunger barrel (18) are maintained in spaced coaxial relation by use of spaced members (32,34) in one embodiment and a single member having spaced apart portions (32',34') joined by a reduced diameter web (33) in a modified embodiment.

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Attleboro, MA, United States of America

Stephen A Boyle