Location History:
- Hamana, JP (1986)
- Shizuoka, JP (1986)
- Hamamatsu, JP (1994 - 1998)
Company Filing History:
5 out of 1,061 
1 out of 17 Years Active: 1986-1998
Title: Innovations in Marine Propulsion by Yoshitsugu Sumino
Introduction
Yoshitsugu Sumino is a notable inventor based in Hamamatsu, Japan, recognized for his contributions to marine propulsion technology. With a total of six patents to his name, Sumino has developed innovative solutions that enhance the performance and efficiency of watercraft.
Latest Patents
Among his latest patents is a design for a propeller system aimed at improving the performance of outboard drives. This system features a pair of counter-rotating propellers that rotate in opposite directions about a common axis. The rear propeller has a smaller diameter, approximately 92% of the front propeller, and its blade face surface area is about 85% of the front propeller's total area. The design ensures that both propellers have similar camber and pitch, with the rear propeller pitch ranging between 90% and 110% of the front propeller pitch. These parameters significantly enhance the efficiency of the rear propeller, especially when partially exposed, maximizing thrust.
Another significant patent is for a marine propulsion device that improves the handling and responsiveness of watercraft. This device also utilizes counter-rotating propellers, with the front propeller blades designed to have a mean camber line with a constant radius of curvature. This design reduces cavitation and allows the rear propeller to be positioned closer to the front propeller, thereby minimizing steering torque. The blade sizes are carefully calibrated, ensuring that the rear propeller is no more than thirty percent smaller than the front propeller, with pitch differences kept within one to four percent. These configurations enhance the stability and responsiveness of the watercraft during turns.
Career Highlights
Yoshitsugu Sumino has worked with prominent companies in the marine industry, including Sanshin Kogyo Kabushiki Kaisha and Sanshin Industries Co., Ltd. His work has significantly influenced the design and functionality of marine propulsion systems.
Collaborations
Throughout his career, Sumino has collaborated with talented individuals such as Yasushi Iriono and Hiroshi Harada, contributing to the advancement of marine technology.
Conclusion
Yoshitsugu Sumino's innovative patents and career achievements reflect his dedication to improving marine propulsion systems. His work continues to influence the industry, showcasing the importance of innovation in enhancing watercraft performance.