3481172

Information

• Patent Grant
• 3481172

• References
• Source

• Patent Number

  3,481,172

• Date Filed

  Not available

• Date Issued

  Tuesday, December 2, 1969
  55 years ago

• CPC

  • B21F3/06 - internally on a hollow form
  • B21F3/12 - of interconnected helical springs

• US Classifications

  • 072 - Metal deforming