Cold-headed and roll-formed pick type cutter body with carbide insert
AssigneesSS Indus., Kennametal Inc.
InventorsPaul E. Ewing, B. Randall Grubb
Life of this patent
Estimating the term…
Abstract
A pick type bit is disclosed with an improved socket for a carbide insert. The cutter body of the bit is cold-headed from a steel blank to provide a cylindrical shank and a conical head with a socket in the forward end. The cylindrical shank is roll-formed to provide a retaining groove and an intermediate section is roll-formed to provide an extraction groove between the head and the shank. The cold-heading includes an initial step of squaring-up the forward end of the blank by cold-heading it into cylindrical shape with a flat forward end and then punching the socket. This provides a socket of densified work-hardened steel. The bit is completed by brazing the base of a carbide insert in mating relation with the socket in the head.
Claims7
The method of making a bit comprising a cutter body and a carbide insert having a cylindrical base and a cutting tip with an annular beveled seating flange between the base and the tip, said cutter body being of the type comprising a unitary steel body including a cylindrical shank for supporting said bit and a conical head with a socket in the end thereof adapted to receive said insert, said method comprising the steps of:
- cold-heading a cylindrical steel blank to provide an intermediate blank with a cylindrical shank and a conical head with a socket in the forward end of the head, said cold-heading including the steps of squaring-up the forward end of said blank by cold-heading thereof into cylindrical shape with a flat forward end, preforming said blank with a conical recess on the forward end thereof by a forming die working against the forward end of said blank, and punching a cylindrical hole into the central portion of said conical recess leaving an annular beveled seating surface surrounding said hole,
- reducing said cylindrical shank by roll-forming to provide a neck defining a first annular groove in the shank,
- reducing said cylindrical shank by roll-forming to provide a neck defining a second annular groove between the head and said first annular groove,
- and brazing the base and seating flange of said carbide insert to the socket.
A cutting bit comprising a cutter body and a carbide insert,
- said cutter body comprising a unitary steel body including a cylindrical shank for supporting the bit and a conical head on said shank with a socket in the end thereof adapted to receive a carbide insert said socket comprising a cylindrical hole surrounded by a annular beveled seating surface, said steel body also including a cylindrical section between said shank and said head,
- said unitary steel body being cold-headed to form said conical head with said socket in the end thereof and to form said cylindrical shank and cylindrical section, whereby said steel body comprises work-hardened steel,
- said shank being roll-formed after being cold-headed to form an annular retaining groove in said shank,
- said cylindrical section being roll-formed after being cold-headed to form an annular extraction groove in said section,
- said socket being formed of densified, work-hardened steel as a result of said cold-forming and adapted to receive said carbide insert,
- said carbide insert having a cylindrical base and a cutting tip with an annular beveled flange between the base and the tip, said cylindrical base being disposed in said hole with said flange disposed opposite said seating surface, and a brazed joint between said base and said socket and between said flange and said socket.
Dependencies are inferred from the claim text.