Forward Citations = 9

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8 inventors (with patents filed for the assignee):

Hiromichi Yamashita (1 out of 9 patents)

Toshio Akesaka (1 out of 36 patents)

Hiroji Tanaka (1 out of 1 patent)

4. Nobuharu Hayashi (1 out of 1 patent)

5. Kazuto Hamada (1 out of 2 patents)

6. Kenji Takagi (1 out of 1 patent)

7. Hideaki Mutsuro (1 out of 1 patent)

8. Yoshiharu Watari (1 out of 1 patent)

3 patents: Sort by Forward Citations

1. 5190407 - Rectangular shield excavating machine (1993-03-02),

2. 5150744 - Mooring apparatus (1992-09-29),

3. 4451175 - Method for improving soft ground by sand drain method and cylindrical (1984-05-29),

Company Badge

USPTO Data Jan 1 1976 - Oct 20 2026

3 Patents

#3,548 in Tokyo

#8,932 in Japan

Tokyo, Japan

Penta-Ocean Construction Co., Ltd.

Forward Citations = 9

8 inventors:

Hiromichi Yamashita (1 out of 9 patents)

Toshio Akesaka (1 out of 36 patents)

Hiroji Tanaka (1 out of 1 patent)

4. Nobuharu Hayashi (1 out of 1 patent)

5. Kazuto Hamada (1 out of 2 patents)

IDiyas Innovation Intelligence. (2026). Company Patent Portfolio: Penta-Ocean Construction Co., Ltd.. Retrieved from https://idiyas.com/company/penta-ocean-construction-company

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]