3855856

Information

• Patent Grant
• 3855856

• References
• Source

• Patent Number

  3,855,856

• Date Filed

  Not available

• Date Issued

  Tuesday, December 24, 1974
  50 years ago

• CPC

  • E21B33/1208 - characterised by the construction of the sealing or packing means
  • E21B33/1277 - characterised by the construction or fixation of the sleeve
  • E21B47/0915 - using impression packers

• US Classifications

  • 073 - Measuring and testing