Abstract: A spring-loaded operating mechanism for a high-voltage circuit-breaker comprises, between a motor and a trigger shaft, a freewheel-type coupling device which comprises first and second friction members (5, 6) coaxially mounted on a secondary shaft (1). The first friction member (5) is screwed onto the secondary shaft (1) and the second friction member can freewheel about the secondary shaft (1) while being disposed between the first member and an axial abutment (8). The two members (5, 6) are substantially in abutment one against the other along the secondary shaft (1), and the first member is screwed or is unscrewed along the secondary shaft depending on whether it is rotated by the shaft or by the second member. The device does not require any greasing; it operates without maintenance. In addition, the forces exerted by one friction member on the other are low, thereby improving the reliability of the operating mechanism.

Abstract: A spring-loaded operating mechanism for a high-voltage circuit-breaker comprises, between a motor and a trigger shaft, a freewheel-type coupling device which comprises first and second friction members (5, 6) coaxially mounted on a secondary shaft (1). The first friction member (5) is screwed onto the secondary shaft (1) and the second friction member can freewheel about the secondary shaft (1) while being disposed between the first member and an axial abutment (8). The two members (5, 6) are substantially in abutment one against the other along the secondary shaft (1), and the first member is screwed or is unscrewed along the secondary shaft depending on whether it is rotated by the shaft or by the second member. The device does not require any greasing; it operates without maintenance. In addition, the forces exerted by one friction member on the other are low, thereby improving the reliability of the operating mechanism.