There is provided a method of manufacturing a metal shell formed body by cold forging for a metal shell of a spark plug. In the manufacturing method, a semi-finished formed body is first provided with a second inner step without the formation of an annular front end portion. After the semi-finished formed body is inserted from its front end side into a die, a punch is pushed into the semi-finished formed body from its rear end side. By pushing the punch, an annular front-facing surface of the punch is pushed onto the second inner step so as to press a front end portion of the formed body against an annular front end portion forming part of the die. By such a forming step, the metal shell formed body is obtained in which the annular front end portion is formed by extrusion.

There is provided a method of manufacturing a metal shell formed body by cold forging for a metal shell of a spark plug. In the manufacturing method, a semi-finished formed body is first provided with a second inner step without the formation of an annular front end portion. After the semi-finished formed body is inserted from its front end side into a die, a punch is pushed into the semi-finished formed body from its rear end side. By pushing the punch, an annular front-facing surface of the punch is pushed onto the second inner step so as to press a front end portion of the formed body against an annular front end portion forming part of the die. By such a forming step, the metal shell formed body is obtained in which the annular front end portion is formed by extrusion.

The invention discloses a cold forming method for forming power pins and a power pin formed thereof. The cold forming method for forming power pins comprises the following steps: step 1: cutting blank out; step 2: pre-forming the power pin body by necking; step 3: trimming the pre-formed power pin body, and pre-forming a pin fixing disk; step 4: forming the pin fixing disk and a staggered weld leg of pin. The invention also discloses a power pin formed by the cold forming method, composed of a power pin body, a pin fixing disk and a staggered weld leg of pin which are integrally formed into one piece by the cold forming method. The invention achieves high-speed automatic production and high production efficiency with a simple process, and improves material utilization and strength.

The invention discloses a cold forming method for forming power pins and a power pin formed thereof. The cold forming method for forming power pins comprises the following steps: step 1: cutting blank out; step 2: pre-forming the power pin body by necking; step 3: trimming the pre-formed power pin body, and pre-forming a pin fixing disk; step 4: forming the pin fixing disk and a staggered weld leg of pin. The invention also discloses a power pin formed by the cold forming method, composed of a power pin body, a pin fixing disk and a staggered weld leg of pin which are integrally formed into one piece by the cold forming method. The invention achieves high-speed automatic production and high production efficiency with a simple process, and improves material utilization and strength.

Provided is a method and an apparatus for manufacturing a lance nozzle comprising: a casting step for primarily manufacturing the lance nozzle comprising a plurality of discharge pipes, which discharge a gas supplied through an inlet to an outlet, and a front wall with a plurality of discharge holes, each of which is connected to the outlet of the discharge pipe; and a forging step for forming forging structure by forging a circumference of the discharge holes in a front surface of the front wall positioned on an opposite side to the discharge pipes.

Provided is a method and an apparatus for manufacturing a lance nozzle comprising: a casting step for primarily manufacturing the lance nozzle comprising a plurality of discharge pipes, which discharge a gas supplied through an inlet to an outlet, and a front wall with a plurality of discharge holes, each of which is connected to the outlet of the discharge pipe; and a forging step for forming forging structure by forging a circumference of the discharge holes in a front surface of the front wall positioned on an opposite side to the discharge pipes.

A screw plug for a liquid conduit, particularly an oil pipe or an oil container, comprising a cylindrical shaft that is placed on a top plate and is provided with an external thread. A pocket hole having a polygonal cross section is centrally arranged on the top plate as a receiving member for a tool. The shaft is embodied as a tubular butt that is provided with the external thread. A pocket hole which is arranged coaxial to the pocket hole of the top plate extends from the face of the shaft. In order to produce the screw plug, a blank comprising the cylindrical tubular butt that is connected to the top plate in a molded on manner is made, the inner diameter and outer diameter of the tubular butt being smaller than the final corresponding diameters (e, f) of the screw plug. The tubular butt of the blank is then enlarged by applying pressure to the inner wall surface of the pocket hole thereof. Also disclosed is a tool in which one end of a pressure die is fixed as a mandrel-type tool while a supporting or holding head which is disposed so as to be movable relative thereto and encompass a seat for a blank is associated with the free end thereof.

A screw plug for a liquid conduit, particularly an oil pipe or an oil container, comprising a cylindrical shaft that is placed on a top plate and is provided with an external thread. A pocket hole having a polygonal cross section is centrally arranged on the top plate as a receiving member for a tool. The shaft is embodied as a tubular butt that is provided with the external thread. A pocket hole which is arranged coaxial to the pocket hole of the top plate extends from the face of the shaft. In order to produce the screw plug, a blank comprising the cylindrical tubular butt that is connected to the top plate in a molded on manner is made, the inner diameter and outer diameter of the tubular butt being smaller than the final corresponding diameters (e, f) of the screw plug. The tubular butt of the blank is then enlarged by applying pressure to the inner wall surface of the pocket hole thereof. Also disclosed is a tool in which one end of a pressure die is fixed as a mandrel-type tool while a supporting or holding head which is disposed so as to be movable relative thereto and encompass a seat for a blank is associated with the free end thereof.

A method of manufacturing a metal fitting having a tool engagement portion engageable with a tool. The manufacturing method includes a cold forging process, wherein the cold forging process includes: a step (a) of forming a body portion having a first maximum length and a butt portion being continuous to the body portion and having a second maximum length larger than the first maximum length; and a step (b) of drawing at least a part of the butt portion in the axis direction, thereby forming the tool engagement portion.

A method of manufacturing a metal fitting having a tool engagement portion engageable with a tool. The manufacturing method includes a cold forging process, wherein the cold forging process includes: a step (a) of forming a body portion having a first maximum length and a butt portion being continuous to the body portion and having a second maximum length larger than the first maximum length; and a step (b) of drawing at least a part of the butt portion in the axis direction, thereby forming the tool engagement portion.