Patent ID: 6900651

Claim:
An electroconductive contact unit assembly comprising an electroconductive contact unit in the form of a coil spring for resiliently contacting an object to be contacted, the contact unit being coaxially received in a through hole formed in an insulating support member, characterized by that: the through hole having a first diameter in an intermediate portion positioned between first and second axial ends and a reduced diameter portion adjacent at least one of the axial ends; the contact unit in the form of a coil spring comprising a coil spring portion having a coarsely wound portion positioned in the intermediate portion of the through hole and at least one electrode pin portion comprising a closely wound portion at one end of the coil spring portion, the closely wound portion having a tapered or stepped shape so as to be prevented from coming off by the reduced diameter portion; only the closely wound portion of the contact unit being surface processed so as to include a first layer of electroconductive material that covers an outer surface defined by a plurality of turns of the closely wound portion of the coil spring in a continuous manner.