METHOD AND APPARATUS FOR MANUFACTURING CHAIN STUD

PURPOSE:To manufacture chain studs by a press machine at high productivity, by holding a round steel bar of specified size between two sectional die plates with its both ends projecting by specified length and pressing and striking the both ends in plural stages under cold conditions. CONSTITUTION:A round steel bar, 5-30mm. in diameter and 10-60mm. in length is dropped on sectional dies 22, 22', and held by a grasping device through an air cylinder 41. The air cylinder 41' is moved backward by retreating the rear die 22 by raising a blade 3, and the grasping device is moved down by one step. The tip of the blade 3 is inserted into a gap between a bearing stand 25 and a slider plate 24 by lowering a slide 1, and the round steel bar is held by dies 22, 22'. Descent of the slide 1 advances sliding bodies 11, 11' to the center inside by pushing pieces 4, 4', and both ends of the round bar is press and formed by indentation dies 20, 20'. Then, the dlide 1 is raised and the round steel bar is moved down by one step. Press forming is performed successively in the same way, and an objective product is formed.