| 摘要 |
PURPOSE:To accurately and easily align the center of a plunger and of a pot with each other by a structure wherein the outer diameter of the plunger over almost whole length of the portion onto which the pot is fitted is made nearly equal to the inner diameter of the pot and, in addition, reliefs are formed onto the outer periphery of said portion. CONSTITUTION:Firstly, a top force 2 and a bottom force 2 are fixed under the state that the centers of a pot 8 and of a plunger 9 are aligned preliminarily with each other. The plunger 9 and a rod 10 are kept in a properly abutted state against each other by means of flange parts 12 and 13, both of which are pressed with each other by a compression spring 14. When the rod 10 is lowered, the plunger 9 fits into the pot 8. The aligning of the centers of the plunger 9 and of the pot 8 is performed by ensuring proper clearance between the plunger 9 and the pot 8 through the slippage of the positions of axis centers of the plunger 9 and of the pot 8 by the amount of adjustment necessary for center alignment. The slippage of the axis centers is realized by the sliding between the flange parts 12 and 13. Because the whole length of the fitting portion 16 of the plunger 9 fits to the pot 8, the axis center of the plunger 9 aligns with that of the pot 8. Because reliefs 17 are formed onto the outer periphery of the plunger 9, its sliding resistance against the pot 8 is reduced. |
