Abstract: An induction heating system includes induction heating apparatuses, each including a high-frequency current transformer, a low-frequency current transformer and a heating coil, a high-frequency input switch connected to the high-frequency current transformer, a low-frequency input switch connected to the low-frequency current transformer, a first power source to output a high-frequency electric power and a low frequency electric power, a second power source, a first power source output switch connectable to the first power source, a second power source output switch connectable to the second power source, and a switch controller. Each induction heating apparatus includes a heater controller to send a signal to the switching controller to turn on one of the first power source output switch and the second power source output switch, to turn off the other, and to switch on or off each of the high-frequency input switch and the low-frequency input switch.

Abstract: An induction heating system includes induction heating apparatuses, each including a high-frequency current transformer, a low-frequency current transformer and a heating coil, a high-frequency input switch connected to the high-frequency current transformer, a low-frequency input switch connected to the low-frequency current transformer, a first power source to output a high-frequency electric power and a low frequency electric power, a second power source, a first power source output switch connectable to the first power source, a second power source output switch connectable to the second power source, and a switch controller. Each induction heating apparatus includes a heater controller to send a signal to the switching controller to turn on one of the first power source output switch and the second power source output switch, to turn off the other, and to switch on or off each of the high-frequency input switch and the low-frequency input switch.

Abstract: An induction heating system includes induction heating apparatuses, each including a high-frequency current transformer, a low-frequency current transformer and a heating coil, a high-frequency input switch connected to the high-frequency current transformer, a low-frequency input switch connected to the low-frequency current transformer, a first power source to output a high-frequency electric power and a low frequency electric power, a second power source, a first power source output switch connectable to the first power source, a second power source output switch connectable to the second power source, and a switch controller. Each induction heating apparatus includes a heater controller to send a signal to the switching controller to turn on one of the first power source output switch and the second power source output switch, to turn off the other, and to switch on or off each of the high-frequency input switch and the low-frequency input switch.

Abstract: Internally threaded device 10 includes a main body 11 having an internal thread portion 13 and a ring-like seat portion 12 disposed between the main body 11 and a member to be fastened 30. The main body 11 has a convex portion 15 and the ring-like seat portion 12 has a concave portion 16, the convex portion 15 and the concave portion 16 have a spherical zone with a center on an axis line. The radius of the spherical shape is set to allow the convex portion 15 and the concave portion 16 to slide earlier than the internal thread portion 13 when a load is applied between the main part 11 and the member 30 in a direction crossing the axial line L. Externally threaded device 40 and washer device 50 in similar structures prevent loosening of the engaged portion easily.

Abstract: Internally threaded device 10 includes a main body 11 having an internal thread portion 13 and a ring-like seat portion 12 disposed between the main body 11 and a member to be fastened 30. The main body 11 has a convex portion 15 and the ring-like seat portion 12 has a concave portion 16, the convex portion 15 and the concave portion 16 have a spherical zone with a center on an axis line. The radius of the spherical shape is set to allow the convex portion 15 and the concave portion 16 to slide earlier than the internal thread portion 13 when a load is applied between the main part 11 and the member 30 in a direction crossing the axial line L. Externally threaded device 40 and washer device 50 in similar structures prevent loosening of the engaged portion easily.

Abstract: Provided are: a welded structural member whose spot-welded part has both strength and ductility, and whose rupture strength proven by a rupture test such as a cross tensile test is high; and a method for welding such a structural member. The welded part 3 of the welded structural member 1 made of the above steel plates bonded by overlapping their faces and forming the welded part 3 by spot welding includes: a molten and solidified part 4; and a heat-affected zone 5 surrounding the molten and solidified part 4. The hardness on the welded surface increases to harder than the hardness of the steel plates 2 (base material) along a direction from a region outside the heat-affected zone 5 toward the heat-affected zone 5.

Abstract: An induction heating system includes induction heating apparatuses, each including a high-frequency current transformer, a low-frequency current transformer and a heating coil, a high-frequency input switch connected to the high-frequency current transformer, a low-frequency input switch connected to the low-frequency current transformer, a first power source to output a high-frequency electric power and a low frequency electric power, a second power source, a first power source output switch connectable to the first power source, a second power source output switch connectable to the second power source, and a switch controller. Each induction heating apparatus includes a heater controller to send a signal to the switching controller to turn on one of the first power source output switch and the second power source output switch, to turn off the other, and to switch on or off each of the high-frequency input switch and the low-frequency input switch.

Abstract: A hardening apparatus (10), comprising a heating zone (20) induction heating coiled members (12) to a hardening temperature and cooling zone (30) rapidly cooling the coiled members (12) induction heated to the hardening temperature. A carrying route (22) for carrying the coiled members (12) in the direction of arrow A (carrying direction) while the coiled members are rotating and an induction heating coil (24) for induction heating the coiled members (12) being carried on the carrying route (22) while the coiled members are rotating are disposed in the heating zone (20). The large number of coiled members (12) are placed on the carrying route (22) at specified intervals so that the longitudinal direction thereof crosses the carrying direction and carried continuously.

Abstract: A hardening apparatus (10), comprising a heating zone (20) induction heating coiled members (12) to a hardening temperature and cooling zone (30) rapidly cooling the coiled members (12) induction heated to the hardening temperature. A carrying route (22) for carrying the coiled members (12) in the direction of arrow A (carrying direction) while the coiled members are rotating and an induction heating coil (24) for induction heating the coiled members (12) being carried on the carrying route (22) while the coiled members are rotating are disposed in the heating zone (20). The large number of coiled members (12) are placed on the carrying route (22) at specified intervals so that the longitudinal direction thereof crosses the carrying direction and carried continuously.

Abstract: In a method of producing hollow rack bars from steel tubes for use in steering equipment for automobiles and so on, a part of the length of the steel tube to be processed and its adjacent parts is held in split dies that encircle a whole circumference of the tube except for the dies having a hole coinciding with the part of the tube to be processed. Then, a punch is inserted into the hole in a closed state of the dies for flattening a part of the tube, and then mandrels are pushed into the tube for ironing from the inside to form a rack pattern, when a rack forming die is inserted into the hole and held in contact with the flattened part of the tube.

Abstract: In production of hollowed rack bars from steel tubes for use in steering equipment for automobiles and so on, a part of length of the steel tube to be processed and its adjacent parts is held in split dies encircling a whole circumference of the tube except for the dies having a hole coinciding with the part of the tube to be processed. Then, a punch is inserted into the hole at a state of the dies closed for flattening the part of the tube, and then mandrels are pushed into an inside of the tube for ironing from the inside to form a rack pattern, at a state of a rack forming die being inserted into the hole and held in contact with the flattened part of the tube.