Patent ID: 7585193

Claim:
Plug-and-socket connector with screw-type connection, having an insulating part, arranged to accommodate at least one contact insert, the contact insert having a substantially cylindrical shape, comprising a contact portion for electrical/mechanical connection to an oppositely shaped contact piece of a matched plug-and-socket connector at a first end of the contact insert, and comprising an insertion opening for at least one connecting stranded conductor at a second end of the contact insert, there opening in the insertion opening a screw hole which is oriented substantially transversely relative to the central longitudinal axis thereof and comprises an internal thread, and the insulating part having a screw channel which is substantially in alignment with the screw hole of the insertion opening when a contact insert is accommodated in the insulating part, the screw channel having at least one step, wherein the inside width of the screw channel reduces from a first, greater dimension (R 1 ) towards a second, lesser dimension (R 2 ) in the direction towards the screw hole of the insertion opening, and the screw channel having one or more strips which are oriented substantially coaxially relative to its central longitudinal axis of the and which are so dimensioned that a clamping screw to be inserted in the screw channel for the purpose of fastening the connecting stranded conductor or solid wire in the insertion opening of the contact insert is subjected to a first, lesser resistance at the strip/strips of the first inside width, and is subjected to a second, greater resistance at the strip/strips of the second inside width.