Safety Harness System Patent Issued to Yoshikawa Kogyo Co. Ltd.

Strategic Insights -

A newly issued patent by Yoshikawa Kogyo Co. Ltd. has presented a novel technique for determining whether a safety harness hook is used correctly, without complicating the configurations of the hook and the safety rope. The patent, titled "System for confirming hooking state of safety harness," was filed on March 29, 2021, and published online on October 14, 2025. The inventors, Harano, Shinya and Sawada, Kikuzo, have designed a system that detects whether the hook is attached to the hook holder of the safety harness, rather than detecting whether the hook is hooked to the main rope or the like.

Key Takeaways:

  • The patented system determines whether the hook of the safety harness is used correctly by detecting whether the hook is attached to the hook holder, rather than detecting whether the hook is hooked to the main rope or the like.
  • The system comprises a control device with AC induced magnetic field-transmitting means to transmit an AC induced magnetic field, a magnet mounted to the hook, and a tag installed adjacent to the hook holder with a magnetic sensor and AC induced magnetic field-receiving means.
  • The warning system will issue a warning when the AC induced magnetic field-receiving means receives the AC induced magnetic field, and the magnetic sensor detects the magnetism, indicating that the hook is attached to the hook holder and the safety harness is within the detection range of the AC induced magnetic field.
  • The system is designed to simplify the configurations of the hook and safety rope, eliminating the need for a coil and electric signal cable, making it a more practical solution for fall-prevention.
  • The inventors' solution aims to prevent fall accidents by ensuring that workers wear safety harnesses correctly, reducing the risk of accidents and injuries.
  • The system's functionality can be integrated with existing safety equipment, enhancing the overall safety of workplaces, particularly in construction sites.

Statistics:

  • The patent was filed on March 29, 2021.
  • The patent was published online on October 14, 2025.
  • The system uses a control device with AC induced magnetic field-transmitting means to transmit an AC induced magnetic field.
  • The magnet mounted to the hook is paired with a tag installed adjacent to the hook holder, containing a magnetic sensor and AC induced magnetic field-receiving means.
  • The system's warning functionality detects whether the hook is attached to the hook holder and the safety harness is within the detection range of the AC induced magnetic field.

Sources:

  • Harano, Shinya. "System for confirming hooking state of safety harness." U.S. Patent Number 12440711, filed March 29, 2021, and published online on October 14, 2025.
  • VerticalNews. "Yoshikawa Kogyo Co. Ltd. Awarded Patent for System for Confirming Hooking State of Safety Harness." October 14, 2025.