Description
Class E21D : SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
Subclass 1/04: Sinking shafts mechanically (E21D 1/08 takes precedence) with grabs
E21D 1/04
Sub-Class
Stats
- 0 US PATENTS IN FORCE
- 0 US APPLICATIONS PENDING
- 0 Total Patent Owners
- 0 TOTAL INVENTORS
Recent Patents
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Recent Publications
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Patents Issued To Date - By Filing Year
Average Time to Issuance
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- 0 Months (last 5 years Issuances)