3557612

Information

• Patent Grant
• 3557612

• References
• Source

• Patent Number

  3,557,612

• Date Filed

  Not available

• Date Issued

  Tuesday, January 26, 1971
  54 years ago

• CPC

  • G01V1/186 - Hydrophones
  • E21F17/185 - Rock-pressure control devices with or without alarm devices; Alarm devices in case of roof subsidence
  • G01N3/064 - with hydraulic indicating or recording means

• US Classifications

  • 073 - Measuring and testing