Electromechanical Optimization of an Eccentric Hedge Trimmer Mechanism with Respect to Cutting Force

Hedge trimmers commonly employ eccentric cam mechanisms to convert rotary motion into reciprocating blade motion. While this solution offers compactness and manufacturability, the eccentric's geometric design strongly influences blade kinematics, cutting force characteristics, vibration levels, and electrical power consumption. This paper presents a geometry-driven optimization framework for an eccentric hedge-trimmer mechanism, based on a coupled electromechanical model of the drive system. The blade's motion, velocity, and acceleration over time depend on both its eccentric shape and its rotation speed. A simplified cutting force model is introduced, linking blade kinematics to cutting resistance, while electrical power consumption and current demand are calculated through the motor model. The results show that properly calibrated geometric parameters for the eccentric mechanism increase system energy efficiency and mechanical loading capabilities using existing system elements. The proposed approach supplies practical design guidelines for developing energy-efficient, low-vibration hedge trimmers and demonstrates the usefulness of electromechanical modelling for geometry-based optimization in handheld power tools.