| 摘要 |
PURPOSE:To preclude the advance of a screw more than a given stroke and prevent breakage of the tip of the screw by a method wherein a stopper is provided between a pusher plate, advancing the screw, and a front plate, fixing a heating cylinder. CONSTITUTION:When a servomotor, operating in conjunction with a timing gear 11, is driven to rotate a ball screw 7, the pusher plate 6 is advanced, therefore, the screw 2 is pushed forward by the pusher plate 6 through a screw sleeve 13 and injection is effected. Since the stroke of the screw 2 is controlled by a controller, the servomotor is stopped when the screw has been advanced to a predetermined position. In case the screw 2 is pushed by mistake to a position exceeding the predetermined advancing position of the screw 2, the stopper 21 abuts against a barrel nut 18 or the like and precludes the further advancement of the pusher plate 6, therefore, the top end of the screw 2 may be prevented from colliding against by cylinder 1. |
