FIELD: electrical engineering. SUBSTANCE: operating mechanism has closing shaft free to rotate about its axis, large gear mounted on mentioned shaft, small gear engageable with large one for tensioning closing spring, and device preventing wedging of large and small gears upon releasing the shaft. Mentioned device is distinguished by profiles of teeth on large and small gears. Large gear has first tooth-to-tooth gap followed by first deflecting tooth designed for backward deflection along tooth axis to oppose tension of compression spring. This tooth is followed by second gap whose length is not less than two pitches of tooth engagement and slightly smaller than integer number of pitches. Second gap is followed by second deflecting tooth also designed for backward deflection along tooth axis to oppose tension of compression spring. Each deflecting tooth and first non- deflecting one that follows last deflecting tooth have side surfaces radially meeting by outer surfaces on common edge and inclined surface in their upper areas abutting against edge. EFFECT: provision for eliminating maladjustment of operating mechanism. 9 cl, 18 dwg
