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 grant trajectory.
- 962
- US patents granted
- #3/4
- in E21
- 2.3%
- E21 class share
- +29%
- 5-yr velocity
The verdict
According to USPTO PatentsView, Shafts ranks #465 of 670 CPC technology areas - 962 US patents granted since 2015, with recorded grant volume up 29% over five years.
- #465
- of 670 CPC technology areas
- 962
- US patents granted, 2015–2025
- Joy Global Underground…
- leading assignee (48)
- +29%
- grant velocity, last 5 yrs
How E21D's grant cadence moved
Between 2020–2024, E21D recorded 434 grants versus 336 in 2015–2019 (+29% equal-window velocity). Across complete years, output peaked in 2019 at 96 grants and bottomed in 2017 at 47 (+104% peak-over-trough). Lead assignee Joy Global Underground Mining LLC holds 5.0% of the class ; the top three share 12.5%.
Leaderboard read
E21D concentration, lead at 5.0%
Joy Global Underground Mining LLC leads this historical grant record at 5.0% of E21D - foreign corporation assignees hold 66% of class grants (365 of 554). Figures describe granted US utility patents in this CPC subclass, not current investment or legal strength.
- Leader's share
- 5.0%
- Top three share
- 12.5%
- Lead over #2
- 3
48 of 962 grants
of the class's recorded grants
more grants than China University of Mining and Technology
Where E21D sits inside E21
Among 4 subclasses in E21 (Earth OR Rock DRILLING; Mining), E21D ranks #3 and holds 2.3% of the parent class's 42,682 recorded grants. Sibling chips below are the other subclasses in the same parent class, not the nationwide volume/lead-share peers further down.
Rising assignees active in E21D
Company-wide grant multiples (2022–2024 vs 2019–2021) among assignees with ≥5 patents in this subclass. Growth is company-wide; class patent counts are subclass-specific.
- #1 Sandvik Mining and Construction Tools AB 15x 0 → 15 company-wide · 6 in E21D
- #2 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences 6.25x 4 → 25 company-wide · 6 in E21D
- #3 Innovative Mining Products (PTY) Ltd 4.00x 0 → 4 company-wide · 6 in E21D
- #4 ArcByt, Inc. 3.50x 2 → 7 company-wide · 7 in E21D
- #5 Shandong University 2.92x 52 → 152 company-wide · 17 in E21D
E21D grants by year, peak 2019 (96)
US utility-patent grants per year in E21D, 2015–2025 - recent five years are up 29% versus 2015–2019.
Who leads E21D?
The 12 most active assignees in SHAFTS; TUNNELS; GALLERIES; Large Underground Chambers - wider bars mean more grants
- Joy Global Underground…
Joy Global Underground Mining LLC
48 patents
- China University of…
China University of Mining and Technology
45 patents
- Sandvik Intellectual…
Sandvik Intellectual Property AB
27 patents
- Sandvik Mining and…
Sandvik Mining and Construction Oy
24 patents
- Herrenknecht…
Herrenknecht Aktiengesellschaft
23 patents
- Fci Holdings Delaware
FCI Holdings Delaware, Inc.
21 patents
- Shandong University 17
Shandong University
17 patents
- Caterpillar Global… 16
Caterpillar Global Mining Europe GmbH
16 patents
- Shandong University… 14
Shandong University OF Science AND Technology
14 patents
- Joy Mm Delaware 12
Joy MM Delaware, Inc.
12 patents
- China University of… 10
China University of Mining and Technology-Beijing
10 patents
- J H Fletcher & 9
J.H. Fletcher & Co.
9 patents
What this shows Joy Global Underground… 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.
View data table
| 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 |
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.
Classes near E21D's 962-grant footprint
Nationwide nearest neighbors for E21D (#465 of 670 by volume ; lead share 5.0%) - not the E21 parent-class siblings above.
Questions about E21D
Which company holds the most patents in E21D?
Which E21D assignees grew fastest recently?
How does E21D compare inside parent class E21?
What to do with this data
E21D in context - here's where to go next.
- Joy Global Underground Mining LLC leads E21D with 48 grants in this class. See full portfolio
- E21D ranks #465 of 670 by grant volume among all tracked CPC technology areas. See the ranking
- Inside parent class E21, the largest sibling subclass is E21B with 39,943 grants. Explore E21B
Figures reflect USPTO PatentsView grant data through 2026-05-15; pending applications not yet granted are not counted.
Methodology - E21D figures are USPTO PatentsView granted-utility totals for this subclass (962 grants in the tracked window).
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.