Time Lock, Fluid-controlled Patents (Class 70/DIG50)
  • Tumbler lock alarm construction
    Patent number: 4114412
    Abstract: The invention provides a tamper-proof pin tumbler lock construction cooperative with an alarm means and protective against unauthorized picking or core drilling activities on the lock while securing normal key opening and closing procecures therefor. The construction energizes an alarm if the unauthorized activities exceed a predetermined time limit required for normal key opening and closing procedures.
    Type: Grant
    Filed: February 24, 1977
    Date of Patent: September 19, 1978
    Inventor: Willi Braatz