| 摘要 |
An exemplary securing means has an electromagnet which has a core, a coil and a yoke which can be moved away from the core and which closes the magnetic circuit of the electromagnet. This securing means is provided with an electrical or electronic switching device which responds to a magnetic field for monitoring of the magnetic field in the magnetic circuit. This switching device taps the core or the yoke at two sites which are spaced apart from one another in the lengthwise direction of the magnetic flux. Thus, the switching device reacts distinctly to the gap width between the core and the yoke. For example, a reed switch drops out at a gap width of 0.02 mm, but is clearly activated when the magnetic circuit is closed.
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