Description
Class E21D : SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
Subclass 1/02: Sinking shafts by hand
E21D 1/02
Sub-Class
Stats
- 0 US PATENTS IN FORCE
- 0 US APPLICATIONS PENDING
- 0 Total Patent Owners
- 0 TOTAL INVENTORS
Recent Patents
Not Available
Recent Publications
Not Available
Top Owners in This Subclass
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Patents Issued To Date - By Filing Year
Average Time to Issuance
- 0 Months (last 2 years Issuances)
- 0 Months (last 5 years Issuances)