| 摘要 |
PURPOSE: To obtain a damper which can be used in a device for stabilizing intervertebra by composing a stop which resists the motion of a piston that exceeds a predetermined quantity of displacement of a piston by a resistance means. CONSTITUTION: When a compressive force acts against ball joints 11 and 31, a piston 3 begins to move from a rest position in contact with a cover 2 to a bottom of a cylinder 1. An elastic member 4 which receives resistance from a strong wall of the cylinder 1 by this motion begins to deform, and the elastic member 4 resists the motion of the piston 3, and the resistance increases progressively. When the volume of a chamber 12 becomes equal to the volume of the elastic body 4 in a state in which the volume of the chamber 12 has already been compressed, resistance that is exerted on the motion of the piston 3 by the elastic member 4 increases in an exponential functional manner, and in a critical point, the piston 3 forms a stop that hinders further motion. In this way, the piston 3 stops. |
