Patents Assigned to Robinson Foundry, Inc.
  • Valve stem
    Patent number: 4941644
    Abstract: A valve stem formed by evaporative pattern (or lost foam) casting a hollow or solid rod member inside of the elongated outer member. Since the stem is thereby cast to near net shape, little machining is required to finish it. The elongated member can have on its outer surface coarse square threads, a thrust ring, a flattened transition and a retaining nut threaded end. The rod member can advantageously be made of a material that is stronger and less expensive than that of the copper base alloy of the elongated member.
    Type: Grant
    Filed: January 9, 1990
    Date of Patent: July 17, 1990
    Assignee: Robinson Foundry, Inc.
    Inventor: Richard H. Robinson
  • Valve stem construction
    Patent number: 4916789
    Abstract: A valve stem formed by evaporative pattern (or lost foam) casting a hollow or solid rod member inside of the elongated outer member. Since the stem is thereby cast to near net shape, little machining is required to finish it. The elongated member can have on its outer surface coarse square threads, a thrust ring, a flattened transition and a retaining nut threaded end. The rod member can advantageously be made of a material that is stronger and less expensive than that of the copper base alloy of the elongated member.
    Type: Grant
    Filed: April 13, 1989
    Date of Patent: April 17, 1990
    Assignee: Robinson Foundry, Inc.
    Inventor: Joseph H. Robinson