FIELD: machine building.
SUBSTANCE: invention relates to drive systems, which include drive and fastening element, namely to fastening element, to nozzle-bit and to punch. Invention is aimed at minimization of voltage at joint of bit contact surfaces and recess, reducing risk of coating damage and premature fatigue destruction of bit. In the fastener head there is an external drive profile or an internal driving recess, wherein said outer drive profile or internal drive recess are formed from lobes with walls between them. Each lobe is made with drive surfaces intended for torque transmission, and each of said drive surfaces in cross section is made in form of evolvent of polygon, which contains serially arranged circular arcs, each of which has its own constant radius different from the rest. Said arcs are convex relative to the central axis of the fastening element.
EFFECT: drive system with complete contact of surfaces is proposed.
24 cl, 53 dwg
