PlainPatent

CPC technology class · E21

E21D - Shafts

Shafts; tunnels; galleries; large underground chambers. 962 US utility patents granted 2015–2025, with the leading assignees and year-by-year filing trajectory.

962
US patents granted
E21
Parent CPC class
20
Active assignees
+52%
5-yr velocity

The verdict

Shafts ranks #465 of 670 CPC technology areas - 962 US patents granted since 2015, with filing up 52% over five years.

#465
of 670 CPC technology areas
962
US patents granted, 2015–2025
Joy Global Undergroun…
leading assignee (48)
+52%
filing velocity, last 5 yrs
Top assignee: Joy Global Underground Mining Llc (48 patents)

CPC subclass E21D - SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS - covers 962 US utility patents granted between 2015 and 2025 according to USPTO PatentsView records, within the broader CPC class E21 (EARTH OR ROCK DRILLING; MINING). See our CPC classification guide for how the system works.

The competitive landscape in E21D is shaped by 20 distinct companies actively filing in this space. Joy Global Underground Mining Llc leads with 48 patents, followed by China University Of Mining And Technology at 45 grants and Sandvik Intellectual Property AB at 27.

Filing activity in E21D is up 52% over the past five years versus 2015-2019, a sharp acceleration suggesting an emerging or fast-moving technology area. All counts come directly from USPTO PatentsView and reflect US granted utility patents only.

Is E21D innovation accelerating?

US utility-patent grants per year in E21D, 2015–2025 - recent five years are up 52% versus 2015–2019.

406080100 20152016201720182019202020212022202320242025 76

Who leads E21D?

The 12 most active assignees in SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS - wider bars mean more grants

patents

What this shows Joy Global Undergroun… is the most active filer in E21D, holding 48 of the 962 patents in this class. Concentration at the top signals how contestable this technology area is for new entrants.

Source USPTO PatentsView, granted utility patents As of 2015–2025 grant years
View data table
Top patent holders in CPC subclass E21D
Rank Company Patents in E21D
#1 Joy Global Underground Mining Llc 48
#2 China University Of Mining And Technology 45
#3 Sandvik Intellectual Property AB 27
#4 Sandvik Mining And Construction Oy 24
#5 Herrenknecht Aktiengesellschaft 23
#6 FCI Holdings Delaware, Inc. 21
#7 Shandong University 17
#8 Caterpillar Global Mining Europe Gmbh 16
#9 Shandong University OF Science AND Technology 14
#10 Joy MM Delaware, Inc. 12
#11 China University Of Mining And Technology-beijing 10
#12 J.h. Fletcher & Co. 9
#13 NCM Innovations (pty) Ltd 8
#14 1311854 Ontario Limited 8
#15 J-LOK Co. 8
#16 Bouygues Travaux Publics 8
#17 Hitachi Zosen Corporation 7
#18 Epiroc ROCK Drills Aktiebolag 7
#19 Hypersciences, Inc. 7
#20 Arcbyt, Inc. 7

About This Class

CPC subclass E21D belongs to class E21.

962 patents were granted in this class between 2015 and 2025.

20 companies actively patent in this space.

Classification System

Cooperative Patent Classification (CPC) is a hierarchical patent classification system used by the USPTO and EPO.

← All Technology Classes Technology Rankings →

Footprint here vs. claim strategy

Each dot is a leading E21D assignee, placed by how many patents it holds in this class (horizontal) against its company-wide average claims per patent (vertical) - a read on whether the class is led by broad-but-shallow filers or focused deep-claim players.

Top 14 E21D assignees by class footprint. Bubble size = patents in E21D. Source: USPTO PatentsView (claim depth is company-wide across all classes).

Top 14 E21D assignees by class footprint. Bubble size = patents in E21D. Source: USPTO PatentsView (claim depth is company-wide across all classes). Scatter plot of 14 data points (bubble-sized by third dimension). 510152025 01020304050 Patents in E21D Avg claims / patent (company-wide) Joy Global Undergroun…China University of M…Sandvik Intellectual…Sandvik Mining and Co…Herrenknecht Aktienge…Fci Holdings DelawareShandong UniversityCaterpillar Global Mi…Shandong University O…Joy Mm DelawareChina University of M…J H Fletcher &Ncm Innovations (Pty)1311854 Ontario
Top 14 E21D assignees by class footprint. Bubble size = patents in E21D. Source: USPTO PatentsView (claim depth is company-wide across all classes).

Frequently Asked Questions

What is CPC class E21D?
CPC subclass E21D covers SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS. It belongs to CPC class E21 (EARTH OR ROCK DRILLING; MINING), with 962 US utility patents granted since 2015.
How many patents have been filed in E21D?
962 US utility patents were granted in CPC subclass E21D between 2015 and 2025, based on USPTO PatentsView data.
Which company holds the most patents in E21D?
Joy Global Underground Mining Llc leads E21D with 48 patents, making it the most active assignee in this technology area.
How is patent data for E21D collected?
Patent data comes from USPTO PatentsView, a public research dataset maintained by the United States Patent and Trademark Office. It covers all US granted utility patents and assigns CPC codes based on the technology described in each patent.
What is the difference between CPC class and subclass?
A CPC class (e.g., E21) is a broad technology category. Subclasses like E21D provide finer granularity within that category. PlainPatent organizes data at the subclass level (4-character codes) for the most useful view of technology domains.

Read our methodology - how this data is sourced, computed, and verified.

Data sourced from USPTO PatentsView - official U.S. government patent data. See our methodology for computation details. Retrieved and formatted by PlainPatent Editorial

Every figure on PlainPatent is rendered directly from USPTO source data, no number is typed in by an editor. This page draws directly on USPTO source data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.