Design of a Mechanical Locking Hook with a Memory Mechanism for Carrying Robots in Nuclear Power Plant Decommissioning

This paper presents a design of a mechanical locking hook that enables remote slinging and unslinging operations without the use of electrical components to carry robots at decommissioning sites with high radiation levels. The proposed hook employs a memory mechanism that shifts and holds the rotation angle based on the number of relative reciprocations with a component and can switch between locking and unlocking states based on the number of relative reciprocations with a carried object. Additionally, a method of dimensional synthesis for the MLH considering its payload and interferences between its parts, is proposed. This paper describes the fabrication of a small laboratory prototype and a practical version for carrying robots at an actual decommissioning site. Through experimentation, it has been confirmed that the MLH can effectively perform remote slinging and unslinging operations.