Bolt Loosening Patents: Who Leads, Where the Gaps Are 2026
- Filing has cooled sharply. 2021 to 2024 filings fell 83%, from 6 to 1, on the most recent years that can be treated as complete.
- No single assignee dominates. The leader holds 4 records out of 38 in scope, and the top 5 combined account for 42.1% — concentrated, but not locked up.
- Testing and measurement outweigh the fastener itself. G01M testing-machine claims (26.3% of records) and G01L force-measurement claims (13.2%) together rival F16B fastener claims (28.9%).
Filing growth compares 2021 (6 records) with 2024 (1) — a three-year span. 2024 is the most recent year we treat as complete: publication lags filing by roughly 18 months, so 2025 onwards are still filling in and any growth rate that ends there would understate the field. Top-5 share is the combined record count of the five largest assignees divided by all 38 records in scope (CR5), not by the ranked leaders only.
What this landscape covers
This dataset tracks patent activity at the intersection of bolt loosening detection and thread locking mechanisms — spanning mechanical anti-loosening designs, adhesive and wedge-lock retention methods, and the test rigs built to quantify clamp force retention under vibration. Records range from 2015 through the 2026 cut-off, with 38 records in scope across the assignee ranking.
The field sits across two distinct claim types: physical locking hardware (thread inserts, wedge washers, adhesive coatings) and the diagnostic machines and algorithms used to measure or predict loosening under transverse vibration. That split matters for freedom-to-operate work, because a filing in one branch rarely blocks the other.
Filing trend and technology composition
Two views of the same 38-record dataset: filing activity by year, and where those records sit across IPC subclasses.
Filing trend, 2017–2026
Filings peaked at 7 in 2018. The 2021-to-2024 span, the most recent period treatable as complete, shows a decline of 83% (6 to 1). Publication lags filing by roughly 18 months, so 2025 and 2026 figures will fill in and should not yet be read as a continued fall.
Technology composition by IPC subclass
F16B (fasteners) leads at 28.9% of the 38 records, closely trailed by G01M (testing machines) at 26.3% and G01L (force measurement) at 13.2%. F01D (turbines), B05D (coatings), G06F (digital processing) and the two agricultural subclasses (A01C, A01D) each cover a smaller slice, pointing to bolt-loosening concerns migrating into adjacent equipment domains rather than staying purely mechanical.
Shares are the percentage of the 38 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Bolt Loosening and Thread Locking with Eureka
This page is one run against one query. Ask Eureka your own question about bolt loosening and thread locking and every answer comes back with the patent numbers behind it.
Try EurekaMost-cited records in this dataset
Multi-bolt loosening test machine for flange with tension, bending and torsion compound loading
Filed by Dalian University of Technology and published 2020-03-12, this record describes a test machine that applies combined tension, bending and torsion loads to multi-bolt flange connections — extending earlier two-load test rigs to a full three-load compound loading capability.Abstract condensed from the original filing.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US4325985A | Thread lock | 67 |
| 2 | US4428982A | Thread lock | 64 |
| 3 | US20200080914A1 | Multi-bolt loosening test machine for flange with tension, bending and torsion compound loading | 23 |
| 4 | US20200080905A1 | Multi-bolt loosening test machine for flange with tension and bending compound loading | 14 |
| 5 | CN114266280A | 一种基于改进卷积神经网络的螺栓松动状态识别方法 | 8 |
| 6 | US20180140066A1 | Article organization and storage device | 8 |
| 7 | US20240184940A1 | Digital twin data model driven high-performance virtual simulation method and system | 6 |
| 8 | WO2019071843A1 | 螺栓松动下纤维增强复合盘鼓薄壁构件旋转振动试验台 | 6 |
| 9 | US10278466B2 | Article organization and storage device | 6 |
| 10 | CN117330270A | 一种车辆螺栓松动寿命评估方法及系统 | 5 |
Citation counts reflect influence within the searched corpus and favour older filings; they are not a measure of current commercial importance.
Patent titles are shown in the language they were filed in, not translated, so that each record stays verifiable against the original filing — a translated title will not match in Eureka or in any national register. Each row carries its publication number; clicking a row searches Eureka by that number.
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Three patterns stand out once the filing trend, assignee spread and technology composition are read together.
Filing activity has pulled back from its 2018 peak
The field peaked at 7 filings in 2018 and has since thinned out, with the 2021-to-2024 window — the most recent complete span — down 83%, from 6 filings to 1. That is a genuine pullback in new filing activity, not a data artefact, though 2025-2026 figures are still filling in under the usual publication lag.
The top of the ranking is concentrated but not cornered
The leading assignee holds 4 records; the top 5 combined account for 42.1% of the 38 records in scope, and the top 10 combined reach 68.4%. That leaves a long tail of single- and double-filing entrants holding roughly a third of the field.
Test-rig and measurement claims rival the fastener claims themselves
F16B fastener hardware leads at 28.9% of records, but G01M testing machines (26.3%) and G01L force measurement (13.2%) together cover a comparable share — signalling that a large part of the claim space is about proving loosening happens, not just preventing it.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to bolt loosening and thread locking, with the prior art for and against each one.
Who is filing, and where the gaps sit
The ranked list covers 27 companies across the 38 records in scope. Filing is led by a handful of university and industrial research groups, with a long tail of single-record entrants including individual inventors.
A modest lead, not a monopoly
The top-ranked assignee holds 4 of the 38 records in scope — enough to lead the field, but far short of dominating it. Recent-year momentum data shows even the most active assignees recorded zero filings in the latest year, consistent with the broader slowdown.
A flat mid-field behind the leader
Fifth place and tenth place both sit at 2 records apiece, meaning the ranking flattens quickly after the leader. That flat middle is where the top-10 concentration figure (68.4% of all 38 records) is built from — a broad group of similarly sized filers rather than a steep drop-off.
Collaboration is limited and clustered
Only 5 co-assignee pairs appear across the dataset, and the strongest repeated pairing involves the same individual inventor appearing alongside three different co-inventors — suggesting small, informal filing teams rather than large joint-venture programmes.
| Assignee | Recent year | YoY |
|---|---|---|
| Siemens Energy Global GmbH & Co. KG | 0 | — |
| Dalian University of Technology | 0 | — |
| Lyu Guigang | 0 | — |
| Beijing University of Technology | 0 | — |
| OAKLAND CORP | 0 | — |
| Southwest Jiaotong University | 0 | -100% |
| Northeastern University (China) | 0 | — |
| TAMBE ABHISHEK BALIRAM | 0 | — |
Where to take this analysis
The landscape points to a field with occupied core claims and thinner coverage at the edges. The next steps depend on whether the goal is freedom-to-operate or new filing.
Map claim boundaries around the top-cited test-rig patents
US4325985A, US4428982A and the Dalian University of Technology flange test-machine filings carry the highest citation counts in this dataset. Any new test-rig or measurement filing should be checked against these claims before development proceeds.
Explore citation networks in EurekaEvaluate the under-claimed adhesive and ML branches
B05D coating overlap and G06F digital-processing overlap each cover a small share of records, suggesting room for a first-mover claim in adhesive locking formulations or ML-based loosening classification.
Run a white space search in EurekaTrack the post-2024 filing recovery
Because publication lags filing by roughly 18 months, 2025 and 2026 records are still incomplete. A follow-up pull in a year will clarify whether the 2021-2024 decline continues or reverses.
Set a filing alert in EurekaCommon questions about this landscape
This dataset contains 38 published records in scope, spanning 2015 through the 2026 data cut-off. That figure reflects a specific search string combining bolt-loosening and thread-locking terms with vibration-test and clamp-force-retention terms, so it is a defined slice of the field rather than every fastener-related patent ever filed. Because publication lags filing by roughly 18 months, the true count for 2025 and 2026 will rise as more records publish.
Filing peaked at 7 records in 2018 and has declined since; the most recent complete span, 2021 to 2024, shows an 83% drop from 6 filings to 1. That is a real pullback in new filing activity over that window. Figures for 2025 and 2026 are still incomplete due to publication lag, so it is too early to call the current trajectory a continued decline versus a floor.
The ranking covers 27 companies across the 38 records in scope, led by an assignee holding 4 records. The top 5 combined account for 42.1% of all records and the top 10 combined reach 68.4%, meaning the field is moderately concentrated but not dominated by a single filer. University research groups and individual inventors both appear among the more active names, alongside a long tail of single-filing entrants.
Mechanical thread locking claims fall largely under F16B (fasteners), which covers 28.9% of the 38 records and includes wedge-lock washers and thread inserts. Adhesive locking methods sit under B05D (coating processes), a much smaller slice at 7.9% of records. That gap suggests adhesive locking formulations are comparatively under-claimed relative to mechanical hardware.
G01M (testing machines) covers 26.3% of the 38 records and G01L (force measurement) another 13.2%, together rivalling the 28.9% share held by F16B fastener claims directly. This reflects that proving loosening occurs under transverse vibration, and measuring clamp force retention reliably, is itself a substantial engineering problem — one that test-rig developers like Dalian University of Technology have patented extensively, as shown by their high-citation multi-bolt test-machine filings.
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Disclaimer. This page is generated from Patsnap Eureka data drawn from a limited snapshot of global patent and scientific-literature records, and is provided for general information and reference only.
Patent data carries inherent limitations: recent filings (typically the most recent 18–24 months) are under-counted due to standard publication lag; counts may be reported at either a patent-family or a patent-record basis and are not always directly comparable; classification, applicant-name, and citation data may contain errors, duplicates, or omissions; and the underlying search query defines and constrains the scope shown. As a result, the analysis may be incomplete or inaccurate and may not reflect the full technology landscape.
Nothing on this page constitutes an exhaustive prior-art, novelty, freedom-to-operate, or validity search, nor does it constitute legal, financial, investment, or professional advice, and it should not be relied upon as such. Any patent, commercial, or strategic decision should be verified independently and reviewed with qualified patent, legal, and domain professionals. Patsnap makes no warranties, express or implied, as to the accuracy, completeness, or fitness for any particular purpose of the information presented.
Machine translation. Assignee and organisation names originally recorded in Chinese, Japanese or Korean have been rendered into English by an AI translation step so that the tables stay readable. These renderings are best-effort and may not match a company’s registered English name; the original name is what the underlying patent record carries, and it is what any Eureka query launched from this page uses.