PURPOSE: To make a sufficient vertical displacement under a static load for supporting at a low natural frequency to improve stability by providing arms with one end coupled to a supporting member for receiving restoring force and by providing a lever with one end coupled to a load carrying platform and the other end coupled to the other end of the arm wherein elastic restoring moment functions between the arm and the lever when the lever is swung at the joint.

CONSTITUTION: A plurality of arms 15 are provided wherein one end is freely swingably coupled to a supporting member 10 extending longitudinally under a load carrying platform 27 and when the arms 15 extend laterally toward both sides to swing respectively, they are subjected to elastic restoring moment by an elastic member 17. On both sides under the load carrying platform 27, levers 30 are provided wherein one end is at least swingably coupled for extending approximately upward or downward while the other end is swingable coupled to the other end of the arm 15, and when the lever 30 is swung at the joint, elastic restoring moment functions between them by an elastic member 22.