| 摘要 |
The invention relates to a contactless proximity switch having a magnetic field dependent switch, with two control members that can be brought into contact with one another and which is used to detect the relative approach or retreat of a body with respect to the switch. It is provided with a permanent magnet for generating a magnetic field for activating the switch. According to Fig. 1, the permanent magnet 14 is disposed in a fixed position with respect to the switch 11. The permanent magnet 14 and the switch 11 are housed in a common case which is disposed on a work cylinder 1. The piston 22, 23, of the work cylinder 1, is used as the body that serves to operate the switch 11 and consists at least in part of a ferromagnetic material. The piston is composed of a double chambered sleeve 22 and a disc 23 of soft iron acting as a support for the double chambered sleeve 22. The switch 11 is joined in a magnetically conductive manner to the permanent magnet 14. When the piston passes in front of the switch 11 and the permanent magnet 14, the magnetic flux in the switch 11 is intensified, thereby bringing the control members 9, 12 of the switch 11 in contact with one another.
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