Shock reduction technique and its application by applying center of percussion

Abstract

Various impact and vibration isolation devices have been widely used to protect anti-vibration devices. These devices are mainly composed of the spring, the damper, and the actuator. This paper proposes another new simpler method to insulate the impact disturbance by using center of percussion (COP). The experimental apparatus according to the principle of COP was prepared to investigate the effectiveness of the impact force isolation. The experimental apparatus is composed of the horizontal one link arm, the pendulum typed hammer to hit the side surface of the one link arm, the force sensor to detect the impact force that acts on the rotating shaft of the one link arm, and the torsion spring. Although the torsion spring is not always necessary in the principle of COP, it plays a role to put back the initial position of the one link arm. For this reason, it is considered that the actual application to the impact isolation needs the torsion spring. The influence of the torsion spring, and the relationship between the hammering point and the impact force on the rotating shaft were investigated. As a result, it was confirmed that the transmission of the impact force was the lowest at the hammering point under the condition of COP. Moreover, numerical simulation of the experimental apparatus was conducted for the theoretical validation. It was confirmed that the simulation results agreed with the experiments. Finally, a low impact pushcart was prototyped as a practical application of the proposed method. Experiments passing over a bump of the pushcart indicated the effective reduction of the impact force by COP.

Keywords

• center of percussion
• shock reduction
• vibration isolation
• hammering test
• impact test
• rigid pendulum