Patent No. EP3854990 (titled "Main Drive High-Pressure Sealing System For Shield Machine And Slurry Balance Shield Machine") was filed by China Railway Construction Heavy Industry on Dec 27, 2018. The application was issued on Sep 27, 2023.

Patent oppositions filed by competitors challenge the validity of a granted patent. These oppositions are typically based on claims of prior art, lack of novelty, or non-obviousness. They are a key part of the process for determining a patent's strength and enforceability.
| Company | Opposition Date | Representative |
|---|---|---|
| HERRENKNECHT | Jun 27, 2024 | KLICKOW & WETZEL PARTGMBB |
The dossier documents provide a comprehensive record of the patent's prosecution history - including filings, correspondence, and decisions made by patent offices - and are crucial for understanding the patent's legal journey and any challenges it may have faced during examination.
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