CPC technology class · F03

F03G - Spring

Spring, weight, inertia or like motors; mechanical-power producing devices or mechanisms, not otherwise provided for or using energy sources not otherwise provided for. 2,252 US utility patents granted 2015–2025, with the leading assignees and year-by-year filing trajectory.

Compiled byPlainPatent Editorial, US Patent Intelligence Editorial Team · May 15, 2026

2,252
US patents granted: F03
Parent CPC class: 20
Active assignees: +30%
5-yr velocity

The verdict

Spring ranks #357 of 670 CPC technology areas - 2,252 US patents granted since 2015, with filing up 30% over five years.

#357
of 670 CPC technology areas: 2,252
US patents granted, 2015–2025: Cambridge Mechatronics
leading assignee (54): +30%
filing velocity, last 5 yrs

Top assignee: Cambridge Mechatronics Limited (54 patents)

CPC subclass F03G - SPRING, WEIGHT, INERTIA OR LIKE MOTORS; MECHANICAL-POWER PRODUCING DEVICES OR MECHANISMS, NOT OTHERWISE PROVIDED FOR OR USING ENERGY SOURCES NOT OTHERWISE PROVIDED FOR - covers 2,252 US utility patents granted between 2015 and 2025 according to USPTO PatentsView records, within the broader CPC class F03 (MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR). See our CPC classification guide for how the system works.

The competitive landscape in F03G is shaped by 20 distinct companies actively filing in this space. Cambridge Mechatronics Limited leads with 54 patents, followed by ICE Thermal Harvesting, Llc at 43 grants and Rondo Energy, Inc. at 41.

Filing activity in F03G is up 30% 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 F03G innovation accelerating?

US utility-patent grants per year in F03G, 2015–2025 - recent five years are up 30% versus 2015–2019.

Cambridge Mechatronics

54
Ice Thermal Harvesting

43
Rondo Energy

41
Tdk Taiwan

38
Hutchinson Technology…

30
Energy Vault

23
Clearmotion

19
Lintec Of America

17
Exergyn

17
The Abell Foundation

15
Saes Getters S P A

11
Ormat

11

What this shows Cambridge Mechatronics is the most active filer in F03G, holding 54 of the 2,252 patents in this class. Concentration at the top signals how contestable this technology area is for new entrants.

View data table

Top patent holders in CPC subclass F03G
Rank	Company	Patents in F03G
#1	Cambridge Mechatronics Limited	54
#2	ICE Thermal Harvesting, Llc	43
#3	Rondo Energy, Inc.	41
#4	TDK Taiwan Corp.	38
#5	Hutchinson Technology Incorporated	30
#6	Energy Vault, Inc.	23
#7	Clearmotion, Inc.	19
#8	Lintec OF America, Inc.	17
#9	Exergyn, Ltd.	17
#10	The Abell Foundation, Inc.	15
#11	SAES Getters S.p.a.	11
#12	Ormat Technologies Inc.	11
#13	Qwtip Llc	11
#14	Aperia Technologies, Inc.	10
#15	Actuator Solutions Gmbh	9
#16	Eavor Technologies Inc.	8
#17	Enhancedgeo Holdings, Llc	7
#18	SMR Patents S.à.r.l.	6
#19	Alfmeier Präzision SE	6
#20	Julius BLUM Gmbh	5

About This Class

CPC subclass F03G belongs to class F03.

2,252 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 F03G 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 F03G assignees by class footprint. Bubble size = patents in F03G. Source: USPTO PatentsView (claim depth is company-wide across all classes).

Frequently Asked Questions

What is CPC class F03G?

CPC subclass F03G covers SPRING, WEIGHT, INERTIA OR LIKE MOTORS; MECHANICAL-POWER PRODUCING DEVICES OR MECHANISMS, NOT OTHERWISE PROVIDED FOR OR USING ENERGY SOURCES NOT OTHERWISE PROVIDED FOR. It belongs to CPC class F03 (MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR), with 2,252 US utility patents granted since 2015.

How many patents have been filed in F03G?

2,252 US utility patents were granted in CPC subclass F03G between 2015 and 2025, based on USPTO PatentsView data.

Which company holds the most patents in F03G?

Cambridge Mechatronics Limited leads F03G with 54 patents, making it the most active assignee in this technology area.

How is patent data for F03G 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., F03) is a broad technology category. Subclasses like F03G 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.