PlainPatent

CPC technology class · B28

B28D - Working Stone Or Stone-like Materials

Working stone or stone-like materials. 1,321 US utility patents granted 2015–2025, with the leading assignees and year-by-year grant trajectory.

1,321
US patents granted
#2/3
in B28
25.7%
B28 class share
-13%
5-yr velocity

The verdict

According to USPTO PatentsView, Working Stone Or Stone-like Materials ranks #421 of 670 CPC technology areas - 1,321 US patents granted since 2015, with recorded grant volume down 13% over five years.

#421
of 670 CPC technology areas
1,321
US patents granted, 2015–2025
Disco
leading assignee (150)
-13%
grant velocity, last 5 yrs

How B28D's grant cadence moved

Between 2020–2024, B28D recorded 548 grants versus 633 in 2015–2019 (-13% equal-window velocity). Across complete years, output peaked in 2019 at 148 grants and bottomed in 2022 at 98 (+51% peak-over-trough). Lead assignee Disco Corporation holds 11.4% of the class ; the top three share 19.5%.

Leaderboard read

B28D concentration, lead at 11.4%

Disco Corporation leads this historical grant record at 11.4% of B28D - foreign corporation assignees hold 80% of class grants (579 of 722). Figures describe granted US utility patents in this CPC subclass, not current investment or legal strength.

Leader's share
11.4%

150 of 1,321 grants

Top three share
19.5%

of the class's recorded grants

Lead over #2
93

more grants than Hilti Aktiengesellschaft

Where B28D sits inside B28

Among 3 subclasses in B28 (Working Cement, Clay, OR Stone), B28D ranks #2 and holds 25.7% of the parent class's 5,141 recorded grants. Sibling chips below are the other subclasses in the same parent class, not the nationwide volume/lead-share peers further down.

B28B 3,309 B28C 511

Rising assignees active in B28D

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. #1 Wolfspeed, Inc. 80x 2 → 159 company-wide · 5 in B28D
  2. #2 Fastbrick IP PTY Ltd 1.33x 12 → 16 company-wide · 10 in B28D
  3. #3 Saint-gobain Abrasives, Inc. 1.23x 35 → 43 company-wide · 14 in B28D
  4. #4 Saint-gobain Abrasifs 1.23x 35 → 43 company-wide · 13 in B28D
  5. #5 JPL Global, LLC 1.20x 5 → 6 company-wide · 5 in B28D

B28D grants by year, peak 2019 (148)

US utility-patent grants per year in B28D, 2015–2025 - recent five years are down 13% versus 2015–2019.

80100120140160 20152016201720182019202020212022202320242025 85

Who leads B28D?

The 12 most active assignees in Working Stone OR Stone-like Materials - wider bars mean more grants

patents

What this shows Disco is the most active filer in B28D, holding 150 of the 1,321 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 B28D
Rank Company Patents in B28D
#1 Disco Corporation 150
#2 Hilti Aktiengesellschaft 57
#3 Husqvarna AB 51
#4 Hamamatsu Photonics K.K. 37
#5 Wirtgen GmbH 34
#6 Siltectra GmbH 25
#7 Siltronic AG 20
#8 The Sollami Company 20
#9 Shin-etsu Handotai Co., Ltd. 18
#10 Saint-gobain Abrasives, Inc. 14
#11 Saint-gobain Abrasifs 13
#12 Caterpillar Paving Products Inc. 12
#13 Germans Boada, S.A. 12
#14 Fastbrick IP PTY Ltd 10
#15 Sumco Corporation 8
#16 Kabushiki Kaisha Miyanaga 8
#17 Bando Kiko Co., Ltd 7
#18 Globalwafers Co., Ltd. 6
#19 SK Siltron Co., Ltd. 6
#20 Perfect Trac Opco, LLC 6

Footprint here vs. claim strategy

Each dot is a leading B28D 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 B28D assignees by class footprint. Bubble size = patents in B28D. Source: USPTO PatentsView (claim depth is company-wide across all classes). Scatter plot of 14 data points (bubble-sized by third dimension). 0510152025 050100150200 Patents in B28D Avg claims / patent (company-wide) DiscoHilti Aktiengesellscha…Husqvarna AbHamamatsu Photonics K…WirtgenSiltectraSiltronicThe SollamiShin-etsu HandotaiSaint-gobain AbrasivesSaint-gobain AbrasifsCaterpillar Paving…Germans BoadaFastbrick Ip Pty
Top 14 B28D assignees by class footprint. Bubble size = patents in B28D. Source: USPTO PatentsView (claim depth is company-wide across all classes).

Classes near B28D's 1,321-grant footprint

Nationwide nearest neighbors for B28D (#421 of 670 by volume ; lead share 11.4%) - not the B28 parent-class siblings above.

Nearest by grant volume

B27B 1,327 F21L 1,327 A22C 1,343 B66D 1,354

Nearest by lead-assignee share

A63J 11.4% G01V 11.4% A61C 11.5% B04C 11.1%

Questions about B28D

Which company holds the most patents in B28D?
Disco Corporation leads B28D with 150 patents (11.4% of the subclass). By PatentsView assignee type, foreign corporations account for 80% of class grants.
Which B28D assignees grew fastest recently?
Among assignees with ≥5 grants in B28D, Wolfspeed, Inc. shows the highest company-wide grant multiple (80x: 2 grants in 2019–2021 → 159 in 2022–2024) while holding 5 patents in this subclass. Growth is company-wide, not class-only.
How does B28D compare inside parent class B28?
Inside B28 (Working Cement, Clay, OR Stone), B28D ranks #2 of 3 subclasses by grant volume and holds 25.7% of the parent class total. The largest sibling is B28B (3,309 grants).

What to do with this data

B28D in context - here's where to go next.

Figures reflect USPTO PatentsView grant data through 2026-05-15; pending applications not yet granted are not counted.

Methodology - B28D figures are USPTO PatentsView granted-utility totals for this subclass (1,321 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.