Cold forcing method and apparatus for producing a terminal

Claim 2

A cold forging method for producing a terminal comprising the steps of: feeding a cylindrical blank material into a swaging die and swaging said cylindrical blank material with a first punch to form a first intermediate product having an enlarged head portion with a shallow recess therein and a center projection disposed respectively above and below a middle portion which has the original outer diameter of the blank material; feeding the first intermediate product into a pre-pressing die and deeply driving a second punch into the center of said recess in said enlarged head to extrude the material backward increasing its axial length thereby to form a second intermediate product having a deep center hole which substantially corresponds in diameter with the outer diameter of said second punch; and feeding the second intermediate product into a forming die so that the head projects from said forming die and striking said head with a third punch comprising a center, a tubular and an outer punch, said center punch being inserted into the center hole of the second intermediate product to maintain the inner peripheral shape thereof, said tubular punch striking the upper surface of the head to form, in cooperation with an inner periphery of the outer punch, a flange between the outer punch and a corresponding contact surface of the forming die and a plurality of detent projections on the bottom surface of the flange.

Claim 3

A cold forging apparatus for producing a terminal which comprises; a swaging press machine including a swaging die having a first die hole comprised of a first portion of substantially the same diameter as the diameter of a cylindrical blank material, a second portion of enlarged diameter formed above said first portion and connected therewith through a first tapered portion and a third portion of reduced diameter into which a first ejector is inserted and formed below and connected with said first portion; a first punch substantially corresponding in diameter with said second portion and having a small projection centrally provided thereunder, said first punch being adapted for swaging said cylindrical material in said swaging die to form an enlarged head portion having a shallow recess and a center projection respectively above and below a midde portion having the original outer diameter of the blank material; a pre-pressing forging machine including a pre-pressing die having a second die hole comprised of a first section of substantially the same diameter as the diameter of said middle portion and an axial length slightly longer than that of said middle portion, a second section of an enlarged diameter substantially corresponding with the outer diameter of said enlarged head portion formed above and connected with said first sectiOn through a second tapered portion and a third section of reduced diameter substantially corresponding with the diameter of said third portion and into which a second ejector is inserted, said third section being formed below and connected with said second section; a second punch substantially corresponding in diameter with the shallow recess and longer than said recess in axial length, said second punch being adapted for striking the first intermediate product and being driven deeply into said recess in the enlarged head to extrude the material backward increasing its axial length thereby to form a deep center hole; a final forging press machine including a forming die having a third die hole comprising a first part which is substantially equal in axial length to the length from the bottom of the intended middle portion of a finished product to the lower end of the intended flange and in diameter to the original outer diameter, a flange-forming second part of an enlarged diameter which is formed above said first part and opens to the upper surface of the forming die, a plurality of tapered grooves formed equiangularly in the bottom of said flange-forming second part, a third part of a reduced diameter substantially corresponding with the diameter of the third portion and the third section and into which a third ejector having a conic projection thereon is inserted, said third part being formed below and connected with said first part; a third punch consisting of a center punch of a diameter corresponding with that of the second punch, a tubular punch slidably fitted around said center punch and biased by a spring and an outer punch encircling said tubular punch and having an inner diameter corresponding with the outer diameter of an intended head of the finished product, said center punch being adapted to be inserted into the center hole of the second intermediate product to sustain the inner peripheral shape thereof, said tubular punch striking an upper surface of the head to form a flange between the outer punch and a corresponding contact face of the forming die, a plurality of detent projections on the bottom surface of the flange and a conical bore in the bottom of the center projection thereby to finish a determined shape of a terminal.

Claim 4

A cold forging apparatus for producing a terminal which comprises; a swaging press machine including a swaging die having a first die hole comprised of a first portion of substantially the same diameter as the diameter of a cylindrical blank material, a second portion of enlarged diameter formed above said first portion and connected therewith through a first tapered portion and a third portion of reduced diameter into which a first ejector is inserted and formed below and connected with said first portion; a first punch substantially corresponding in diameter with said second portion and having a small projection centrally provided thereunder, said first punch being adapted for swaging said cylindrical material in said swaging die to form an enlarged head portion having a shallow recess and a center projection respectively above and below a midde portion having the original outer diameter of the blank material; a pre-pressing forging machine including a pre-pressing die having a second die hole comprised of a first section of substantially the same diameter as the diameter of said middle portion and an axial length slightly longer than that of said middle portion, a second section of an enlarged diameter substantially corresponding with the outer diameter of said enlarged head portion formed above and connected with said first sectiOn through a second tapered portion and a third section of reduced diameter substantially corresponding with the diameter of said third portion and into which a second ejector is inserted, said third section being formed below and connected with said second section; a second punch substantially corresponding in diameter with the shallow recess and longer than said recess in axial length, said second punch being adapted for striking the first intermediate product and being driven deeply into said recess in the enlarged head to extrude the material backward increasing its axial length thereby to form a deep center hole; a final forging press machine including a forming die having a third die hole comprising a first part which is substantially equal in axial length to the length from the bottom of the intended middle portion of a finished product to the lower end of the intended flange and in diameter to the original outer diameter, a flange-forming second part of an enlarged diameter which is formed above said first part and opens to the upper surface of the forming die, a plurality of tapered grooves formed equiangularly in the bottom of said flange-forming second part, a third part of a reduced diameter substantially corresponding with the diameter of the third portion and the third section and into which a third ejector having a conic projection thereon is inserted, said third part being formed below and connected with said first part; a third punch consisting of a center punch of a diameter corresponding with that of the second punch, a tubular punch slidably fitted around said center punch and biased by a spring and an outer punch encircling said tubular punch and having an inner diameter corresponding with the outer diameter of an intended head of the finished product, said center punch being adapted to be inserted into the center hole of the second intermediate product to sustain the inner peripheral shape thereof, said tubular punch striking an upper surface of the head to form a flange between the outer punch and a corresponding contact face of the forming die, a plurality of detent projections on the bottom surface of the flange and a conical bore in the bottom of the center projection thereby to finish a determined shape of a terminal.