| 摘要 |
The emergency off switch for electrically controllable underground mining machines contains an isolating switch (2) in a housing (1) and an operating plunger (4), which can be displaced longitudinally and can be pressed into its switched-off position in the housing against the force of a main spring (5) from a switched-on position projecting out of the housing. A displaceable locking sleeve (9) is supported on the outside of the housing, and an auxiliary spring (10) is arranged between said locking sleeve (9) and a mushroom-head end (7) of the operating plunger, which auxiliary spring (10) acts in the same direction as the main spring on the operating plunger and, on the other hand, in the opposite direction presses the locking sleeve from an unlocking position into a locking position. In the region of the movement path of the locking sleeve, the housing has locking balls (11), which can be displaced radially, rest on the smooth circumference of the operating plunger when the latter is in the switched-on position and block the locking sleeve on an inclined abutting surface (12) against movement into the locking position. When the operating plunger is pressed into the switched-off position, the locking balls can be displaced so far radially inwards from the locking sleeve, by means of their abutting surface, into an annular groove (13) in the operating plunger that they release the locking sleeve to move by means of the auxiliary spring into the locking position, in which the locking balls rest on a stop surface (14) of the locking sleeve. <IMAGE>
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