Patent ID: 8387435

Claim:
An elbow material production device, the elbow material formed by bending to a predetermined angle a metal hollow thick walled member of a given length having a hollow passage of an approximately circular section along an axial direction of the member with ends of the member being open and a periphery of the member being approximately circular or having at least one pair of parallel surfaces, the device comprising: a toggle type link mechanism including a first guide member with a first guide groove, a center pin, a pair of guide plates and a second guide member with a second guide groove, the first guide groove movably guiding the center pin in a first direction perpendicular to an axial direction of the center pin, one end of each of the guide plates being pivotally connected to the center pin, and the second guide groove movably guiding another end of each of the guide plates in a second direction perpendicular to the axial direction of the center pin; two half dies forming a first side die arrangement, the two half dies contacting approximately half of a surface region in the longitudinal direction of the hollow thick walled member to be deformed; first side die arrangement holding members, one for fixedly holding each of the half dies of the first side die arrangement, respectively, one of the holding members being fixedly connected to a lateral surface of each of the guide plates, respectively; a second side die arrangement having a first contact surface and a second contact surface, the first contact surface contacting another portion of the surface of the hollow thick walled member when the member is bent to a predetermined angle, and the second contact surface having a central portion which contacts an outer surface portion of the center pin so as to press the center pin in the first direction; a second side die arrangement holding member for fixedly holding the second side die arrangement; a first mechanism which moves the second side die arrangement holding member in the first direction; and a second mechanism which moves the center pin in the first direction along the first guide groove through contacting the one end portion of the guide plates pivotally connected to the center pin.