TREA

Helmut Letzel

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  • Cologne, DE
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Patents Grantslast 30 patents

  • Information Patent Grant

    Monitoring device
    • Patent number 6,539,760
    • Issue date Apr 1, 2003
    • K. A. Schmersal GmbH & Co.
    • Helmut Letzel
    • E05 - LOCKS KEYS WINDOW OR DOOR FITTINGS SAFES
  • Information Patent Grant

    Apparatus for monitoring and controlling access to a restricted area
    • Patent number 6,283,514
    • Issue date Sep 4, 2001
    • K. A. Schmersal GmbH & Co.
    • Helmut Letzel
    • E05 - LOCKS KEYS WINDOW OR DOOR FITTINGS SAFES
  • Information Patent Grant

    Safety switch device
    • Patent number 5,896,783
    • Issue date Apr 27, 1999
    • K. A. Schmersal GmbH & Co.
    • Helmut Letzel
    • H01 - BASIC ELECTRIC ELEMENTS