Development and performance evaluation of an electric hammer using self-synchronization phenomena

Abstract

In the construction site, an electric hammer, a type of hand held vibrating tool, is used to crush concrete, asphalt and so on. The frequent user of this tool is at high risk for developing the hand-arm vibration syndrome because of excessive exposure to hand-arm vibrations. In order to prevent the disease, it is required to keep the vibration of the tool’s gripes as low as possible. The purpose of the present study is the development of a very low-vibrational electric hammer using self-synchronization phenomena in order to address the problem of the hand-arm vibration syndrome. In previous research, we developed a prototype with synchronous vibration generating mechanism for electric hammer, and performed performance evaluation by sand compaction test. As a result, we succeeded in generating a motion state for the purpose of simultaneously achieving excitation of the striking part and vibration suppression of the holding part. However, there were problems such as lack of impact forces and that the target exercise state did not occur depending on the condition. Therefore, in this study, we tried to change system parameters and DC motor for the purpose of improvement of crushing capacity and stable operation.