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For the Inventor, By the Inventor

Tokyo, Japan

Teikoku Piston Ring Co., Ltd.

USPTO Granted Patents = 70

% Expired Patents = 5.7


Forward Citations = 992

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98 inventors (with patents filed for the assignee):

goldMedal Nobuyuki Yamashita (12 out of 17 patents)

silverMedal Shoji Tanaka (9 out of 9 patents)

bronzeMedal Masao Ishida (8 out of 8 patents)

4.  Kazuhiko Kita (8 out of 28 patents)

5.  Akira Harayama (8 out of 8 patents)

6.  Akihisa Inoue (7 out of 64 patents)

7.  Hitoshi Yamaguchi (7 out of 22 patents)

8.  Tsuyoshi Masumoto (7 out of 49 patents)

9.  Hiroto Fukutome (6 out of 6 patents)

10.  Yoshio Harakawa (6 out of 6 patents)

11.  Yoshio Naruse (5 out of 5 patents)

12.  Akihisa Inoue (5 out of 69 patents)

13.  Giichiro Saito (4 out of 12 patents)

14.  Takatsugu Iwashita (4 out of 4 patents)

15.  Masahiro Oguchi (4 out of 10 patents)


Core Competencies:
Piston Ring
Combined Oil Ring
Cylinder Liner
Sintered Alloy
Hard Coating
Aluminum Alloy
Wear Resistance
Casting Structure
Internal Combustion Engine
Manufacturing Method
Chromium Plating
Sliding Member

70 patents:

1. 8616556 - Combined oil ring (2013-12-31),
2. 8402881 - Insert casting structure (2013-03-26),
3. 8365696 - Piston device for internal combustion engines (2013-02-05),
4. 8037860 - Cylinder liner and engine (2011-10-18),
5. 7963212 - Combination of a piston and a piston ring (2011-06-21),
6. 7882818 - Cylinder liner and engine (2011-02-08),
7. 7717079 - Engine (2010-05-18),
8. 7383805 - Cylinder liner for insert casting and method for manufacturing thereof (2008-06-10),
9. 7077402 - Combined oil ring (2006-07-18),
10. 6951579 - Sintered alloy for valve seats, valve seat and manufacturing method thereof (2005-10-04),
11. 6508473 - Piston ring (2003-01-21),
12. 6454271 - Combined oil ring (2002-09-24),
13. 6372369 - Hard film, sliding member covered with hard film, and manufacturing method thereof (2002-04-16),
14. 6325385 - Piston ring (2001-12-04),
15. 6279913 - Sliding member and manufacturing method thereof (2001-08-28),
Company Overview
Teikoku Piston Ring Co., Ltd., based in Tokyo, specializes in the development and manufacturing of advanced piston ring technologies. The company focuses on core areas such as combined oil rings, cylinder liners, and sintered alloys, emphasizing wear resistance and innovative casting structures. Teikoku's expertise in hard coating and aluminum alloys positions it as a key player in the automotive and industrial sectors, contributing to enhanced engine performance and durability.
Profile summary synthesized from public USPTO records and patent filings.

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USPTO Data Jan 1 1976 - Oct 20 2026

70 Patents

#673 in Tokyo

#1,412 in Japan

#10,649 in the World

Tokyo, JP
Tokyo, Japan

Teikoku Piston Ring Co., Ltd.

Forward Citations = 992

98 inventors:

goldMedal Nobuyuki Yamashita (12 out of 17 patents)

silverMedal Shoji Tanaka (9 out of 9 patents)

bronzeMedal Masao Ishida (8 out of 8 patents)

4.  Kazuhiko Kita (8 out of 28 patents)

5.  Akira Harayama (8 out of 8 patents)

IDiyas Innovation Intelligence. (2026). Company Patent Portfolio: Teikoku Piston Ring Co., Ltd.. Retrieved from https://idiyas.com/company/teikoku-piston-ring-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]
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