A keyswitch includes a base having a pillar, a cap having a rib and movable relative to the base, a sleeve rotatably sleeving the pillar and having first and second top surfaces and convex and concave portions, an elastic member abutting against the sleeve and the base, and a resilient arm abutting against a first or second position on the convex portion with rotation of the sleeve. When the resilient arm abuts against the first position, the rib abuts against the first top surface to prepress the elastic member for generating a first preload. When the cap is pressed for moving the sleeve downward, the resilient arm moves from the first or second position to the concave portion. When the resilient arm abuts against the second position, the rib abuts against the second top surface to prepress the elastic member for generating a second preload larger than the first preload.

A first support member and a second support member are provided in a rotation support device and a worm gear is rotated in a state that the second support member is inserted in the first support member, whereby the worm gear is prevented from being shaken through the first support member and the second support member and heat transmission to a housing due to rotation of the worm gear to damage the housing is prevented.

An energy accumulator (15) for or in an on-load tap changer (10) comprises a motor (11) with an output shaft (12) and a load diverter switch (13) with an input shaft (14), comprising an elastic storage element (17); a transmission coupled to the storage element (17) and having an input hub (201) that can be rotationally fixed to the output shaft (12); an output hub (231) that can be rotationally fixed to the input shaft (14); and a variable transmission (20, 21) interposed between the input hub (201) and the storage element (17).

A manual charging apparatus for a vacuum interrupter, including a motor for charging a closing spring mounted on a vacuum interrupter; a charging shaft configured to rotate by a rotational force of the motor; and a manual charging handle coupled to one end of the charging shaft and configured to manually rotate the manual charging handle, wherein the manual charging handle includes an insertion part formed in an cylindrical shape and inserted into one end of the charging shaft; an extension part vertically bent from the insertion part and extended to increase a revolution torque; and a handle part vertically bent from the extension part and configured to apply a manual operation force, and wherein the insertion part includes a rotation restriction means configured to restrict a rotation in one direction.

The invention relates to a spring controller for high- or medium-voltage electric switchgear, the controller having a free-wheel coupling device between a crank handle or a motor and the drive shaft (1) for driving a switch contact of the switchgear and respectively providing coupling while the spring(s) (11) is/are being loaded and decoupling while the spring(s) is/are being released. The free-wheel mechanical device is incorporated in a toothed wheel (2) of the controller and includes at least one pawl (7, 70) meshing or not meshing with an inner set of teeth (4) of the toothed wheel (2).