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Madison, CT, United States of America

Stonehart Associates Inc.

USPTO Granted Patents = 21

Forward Citations = 478

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13 inventors (with patents filed for the assignee):

Paul Stonehart (10 out of 12 patents)

Masahiro Watanabe (9 out of 26 patents)

Kazunori Tsurumi (8 out of 23 patents)

4. Toshihide Nakamura (5 out of 8 patents)

5. Nobuo Yamamoto (5 out of 5 patents)

6. Koichi Sakairi (3 out of 15 patents)

7. Noriaki Hara (3 out of 8 patents)

8. Tomoyuki Tada (2 out of 10 patents)

9. Yumi Yamamoto (2 out of 2 patents)

10. Haruko Sugimoto (2 out of 2 patents)

11. Takeshi Tozawa (1 out of 3 patents)

12. Masahhiro Watanabe (1 out of 1 patent)

13. Nobuhito Toshima (1 out of 1 patent)

21 patents: Sort by Forward Citations

1. 5922487 - Anode electrocatalyst for fuel cell and process of preparing same (1999-07-13),

2. 5871552 - Process of preparing electrode for solid polymer electrolyte fuel cell (1999-02-16),

3. 5843519 - Process for forming a catalyst layer on an electrode by spray-drying (1998-12-01),

4. 5800938 - Sandwich-type solid polymer electrolyte fuel cell (1998-09-01),

5. 5728485 - Electrode for polymer electrolyte electrochemical cell and process of (1998-03-17),

6. 5607785 - Polymer electrolyte electrochemical cell and process of preparing same (1997-03-04),

7. 5593934 - Platinum alloy catalyst (1997-01-14),

8. 5539002 - Ion exchange resins with decreased resistance to ionic conductivity (1996-07-23),

9. 5523181 - Polymer solid-electrolyte composition and electrochemical cell using the (1996-06-04),

10. 5480851 - Process of preparing catalyst supporting highly dispersed metal particles (1996-01-02),

11. 5472799 - Solid polymer electrolyte fuel cell (1995-12-05),

12. 5453332 - Electrode structure for fuel cell (1995-09-26),

13. 5374598 - Process of preparing metal supported catalyst having high surface area (1994-12-20),

14. 5350727 - Process of preparing catalyst supporting highly dispersed platinum (1994-09-27),

15. 5294232 - Process of preparing solid polymer electrolyte type fuel cell (1994-03-15),

Company Overview

Stonehart Associates Inc., based in Madison, CT, specializes in advanced engineering solutions and consulting services. The company focuses on developing innovative technologies across various sectors, including aerospace, defense, and industrial applications. With a commitment to enhancing operational efficiency and product performance, Stonehart leverages its expertise to address complex challenges in engineering design and project management, contributing to the advancement of technology in its fields of operation.

Profile summary synthesized from public USPTO records and patent filings.

Company Badge

USPTO Data Jan 1 1976 - Oct 13 2026

21 Patents

#2 in Madison, CT

#383 in Connecticut

#15,695 in US

#29,961 in the World

Madison, CT, United States of America

Stonehart Associates Inc.

Forward Citations = 478

13 inventors:

Paul Stonehart (10 out of 12 patents)

Masahiro Watanabe (9 out of 26 patents)

Kazunori Tsurumi (8 out of 23 patents)

4. Toshihide Nakamura (5 out of 8 patents)

5. Nobuo Yamamoto (5 out of 5 patents)

IDiyas Innovation Intelligence. (2026). Company Patent Portfolio: Stonehart Associates Inc.. Retrieved from https://idiyas.com/company/stonehart-associates

Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile

Data Sources: USPTO Patent Grant XML, Patent Center, EPO & CIPO • Normalized by IDiyas Innovation Graph. Methodology & provenance architecturePlease report any incorrect information to [email protected]

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