Abstract: A method of joining using a supporting electrode 4 having a cooling circuit and a pressure electrode 8 movably arranged above the supporting electrode, using a steel material causing martensitic transformation for one of or both of a first member 20 having an opening portion and a second member 24, engaging the second member with the opening portion of the first member, starting conduction from a power supply to the supporting electrode and the pressure electrode, allowing an insertion portion of the second member to enter the opening portion of the first member by a pressure force of the pressure electrode, causing the second member and an inner wall portion of the opening portion to be subjected to solid-phase diffusion joining, rapidly cooling the both members by thermal conduction of the supporting electrode after the joining, and quenching a joined portion and generating compressive residual stress by the rapid cooling.

Abstract: A method of joining using a supporting electrode 4 having a cooling circuit and a pressure electrode 8 movably arranged above the supporting electrode, using a steel material causing martensitic transformation for one of or both of a first member 20 having an opening portion and a second member 24, engaging the second member with the opening portion of the first member, starting conduction from a power supply to the supporting electrode and the pressure electrode, allowing an insertion portion of the second member to enter the opening portion of the first member by a pressure force of the pressure electrode, causing the second member and an inner wall portion of the opening portion to be subjected to solid-phase diffusion joining, rapidly cooling the both members by thermal conduction of the supporting electrode after the joining, and quenching a joined portion and generating compressive residual stress by the rapid cooling.

Abstract: A forced-insertion welded structure is provided which is formed by welding members making up a metal component and which is easy to manufacture and has low cost, a good finish precision and a high bonding strength. The forced-insertion welded structure comprises: a first member 2 with a hole 13 which has the same geometry as a cross section of a forcibly inserted portion of a second member; and the second member 4 having a constant cross section over its length which is similar in shape to the hole 13; wherein a press-fit interference of the second member 4 relative to the hole 13 of the first member 2 is set to 0.

Abstract: A hinge device for use in a foldable device is provided which allows the cover member to be pivoted clockwise and counterclockwise so that the cover member can be used in a variety of ways and also has an excellent functionality. A cellphone using such a hinge device is also provided. A hinge device connecting a body member 13 and a cover member 12 comprises: open-close hinge units 3, 4 to open and close the cover member 12 and to hold the open cover member 12 at a first open position where a cellphone operation can be performed; and a pivotal hinge unit 4 secured to the body member 13 and activated when the cover member 12 is opened beyond the first open position, the pivotal hinge unit 4 being adapted to pivot the cover member 12 clockwise or counterclockwise and to hold the cover member 12 at a pivotal position 90 or 180 degrees clockwise or counterclockwise from the body member.

Abstract: An object of this invention is to provide a hinge device simple in structure, excellent is cost efficiency, and excellent in durability, and a cellular phone using the hinge device. To attain this object, the hinge device includes a tubular member 5, a catch 3 which includes engagement projected parts 38 each having a convex surface with a specified radius of curvature formed thereon, a energizing means 4, and a disk 2 which includes engagement recessed parts 32 engaged with the engagement projected parts in regions opposed to the engagement projected parts 32 of the catch, respectively, and which is rotatably connected with the catch, each of the engagement recessed parts 32 having concave surfaces with a radius of curvature larger than the radius of curvature of the engagement recessed parts formed thereon.

Abstract: This invention relates to a ferule of an optical connector for connecting optical fibers with each other, and an object of the invention is to provide a ferule of an optical connector that can fix and mold a pipe favorably as well as can be manufactured easily.

Abstract: A forced-insertion welded structure is provided which is formed by welding members making up a metal component and which is easy to manufacture and has low cost, a good finish precision and a high bonding strength. The forced-insertion welded structure comprises: a first member 2 with a hole 13 which has the same geometry as a cross section of a forcibly inserted portion of a second member; and the second member 4 having a constant cross section over its length which is similar in shape to the hole 13; wherein a press-fit interference of the second member 4 relative to the hole 13 of the first member 2 is set to 0.

Abstract: Crown twist forming teeth (14) are formed on the inside circumferential surface of a finishing die (13) with the thickness of each teeth being thinner in the middle part than toward both ends in the axial direction. The finishing die (13) is fitted for axial sliding in the axial direction in the axially central part of a die holder (11) through taper surfaces (12a, 13a) diminishing from its one end to the other. A half-finished work (35, 35′) with its outside circumferential surface having rough-formed twist teeth is brought into screw engagement with the finishing die (13). A first punch (25) for pressing the half-finished work (35, 35′) from one axial end toward the other, and a second punch (26) for pressing the finishing die (13) from one axial end toward the other are provided.

Abstract: In a die forging process, projections (4a) are formed on an inner circumference thereof. The projections (4a) are inserted into holes (46) provided in a disc plate (45). The projections (4a) are crushed by a punch 49 so that the disc plate (45) is securely fixed on an inner circumference of the annular gear 41. The process can eliminate a cutting and an electric welding to shorten a manufacturing time.