Helicopter Main Gearbox Patents: Who Leads, Where the Gaps Are 2026
- 88.9% concentration. The top five assignees account for 24 of the 27 records in scope, with a leader at 13 filings and a fifth-place holder at just 2.
- Filing has gone quiet. The tracked trend shows a 2021-to-2024 change of -100%, with 2024 the most recent year that can be read as complete.
- Gearing dominates the claim space. F16H gearing and transmission classes cover 59.3% of the 27 records, well ahead of any other IPC subclass in scope.
Filing growth compares 2021 (3 records) with 2024 (0) — 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 27 records in scope (CR5), not by the ranked leaders only.
A narrow, well-defended field
Helicopter main gearbox and drive train patenting sits in a small, technically dense corner of rotorcraft engineering. The 27 records in scope span loss-of-lubrication survivability, planetary load sharing, spiral bevel gear design and chip detection — problems that recur across every twin- and single-engine platform because a main gearbox failure is a total loss-of-drive event. The claim space is not large by volume, but it is old and heavily cross-referenced: the most-cited record in this set, a gearbox prognosis and diagnostics patent, carries 788 citations, an order of magnitude above anything else in the corpus.
Coverage runs from 2015 through the 2026 cut-off, with the bulk of activity concentrated in a handful of years around a 2018 peak of 13 records. Publication lags filing by roughly 18 months, so any apparent falloff in the most recent one to two years understates real filing activity rather than reflecting an actual stop.
Let an AI agent run this analysis on your own technology
Pick a task. Every answer cites the patents behind it.
Filing trend and technology composition
Two views of the same 27 records: when filings happened, and which IPC subclasses carry the claims.
Filing trend, 2015-2026
Filings peaked at 13 records in 2018 and had fallen to 0 in the tracked 2021-to-2024 comparison, a -100% change over that span. Because publication lags filing by about 18 months, the years closest to the 2026 cut-off should be read as still filling in rather than as a genuine drop to zero.
IPC subclass composition
F16H gearing and transmissions leads at 59.3% of the 27 records, with B64C aeroplanes and helicopters close behind at 55.6% and B64D aircraft equipment at 37.0%. F16C shafts and couplings, G01H vibration measurement and H02K electric motors each appear in a small minority of records, since a single filing can carry several IPC classes these shares add up to more than 100%.
Shares are the percentage of the 27 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Helicopter Main Gearbox and Drive Train with Eureka
This page is one run against one query. Ask Eureka your own question about helicopter main gearbox and drive train and every answer comes back with the patent numbers behind it.
Try EurekaThe most-cited prior art in this field
Aircraft gearbox lubrication system with multiple lubrication subsystems
The filing describes an aircraft gearbox with a housing divided by a barrier into two compartments, each holding drive system components or gears, served by first and second lubrication subsystems that are at least partly independent of one another. The split-subsystem architecture targets survivability after a partial lubrication failure rather than preventing failure outright.Filed by Textron Innovations Inc., published 2020-04-09.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US5210704A | System for prognosis and diagnostics of failure and wearout monitoring and for prediction of life expectancy … | 788 |
| 2 | US4479619A | Helicopter transmission systems | 72 |
| 3 | US3977812A | Compound helicopter drive means | 61 |
| 4 | US20040038768A1 | Pivoting power transmission unit with load transfer via the casing | 27 |
| 5 | US20030168863A1 | Pivoting transmission unit with a device to take up play along the pivot axis | 14 |
| 6 | EP0091744A1 | Helicopter transmission systems | 14 |
| 7 | US20200109776A1 | Hybrid pressurized and non-pressurized lubrication system for aircraft gearbox | 8 |
| 8 | US6915983B2 | Pivoting power transmission unit with load transfer via the casing | 8 |
| 9 | US11313455B2 | Aircraft gearbox lubrication system with multiple lubrication subsystems | 7 |
| 10 | US6830215B2 | Pivoting transmission unit with a device to take up play along the pivot axis | 6 |
Citation counts favour older filings simply because they have had longer to accumulate citations inside a searched corpus; treat them as a signal of influence on later work, not as evidence that a technique is still current.
Each row carries its publication number; clicking a row searches Eureka by that number.
Put your own technology through the same analysis
Eureka on the web
When you want the answer in the next five minutes.
The agent works the prompt against patents and technical literature, citing every source.
Run your analysis now →MCP server & REST API
When it has to run inside your own pipeline.
Patent search, landscape analysis and assignee resolution as MCP tools. Drop them into any agent framework, or call REST directly.
Browse MCP servers →What the numbers mean for a filing decision
Three figures worth acting on before drafting claims in this space.
The field is effectively closed at the top
Five assignees hold 24 of the 27 records in scope. A new entrant is not filing into open ground; it is filing around a small set of incumbents whose claims were laid down years ago and have since accumulated substantial citation weight.
Filing has stalled, not accelerated
The tracked three-year window shows filings falling from 3 in 2021 to 0 in 2024, the most recent year that can be treated as complete. That is consistent with a mature, narrow niche rather than an emerging one.
Gearing claims dominate the corpus
F16H covers the majority of records, with B64C airframe integration and B64D aircraft equipment each appearing in over a third of filings. Bearing, shaft and coupling claims under F16C, and vibration-sensing claims under G01H, appear in only a handful of records each.
One diagnostics patent anchors the field
The gearbox prognosis and diagnostics patent carries 788 citations, far ahead of the next most-cited record at 72. Any monitoring or health-management claim in this space is likely to run into this filing during examination.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to helicopter main gearbox and drive train, with the prior art for and against each one.
Who holds the claims
Eight assignees account for the entire ranked set of 27 records, with filing weighted heavily toward the leader and a fast drop-off after fifth place.
A single assignee holds nearly half the corpus
The top-ranked assignee's 13 records is roughly the combined total of the next four ranked entrants, giving it outsized influence over how gearbox lubrication and load-sharing claims have been drafted in this field.
A steep drop after the top four
Filing weight falls sharply once past the top four assignees; fifth place sits at only 2 records, and the long tail below it holds single-digit counts each.
No assignee shows recent-year momentum
Every assignee in the recent-year momentum breakdown shows zero filings in the latest year, consistent with the broader -100% change tracked from 2021 to 2024 rather than any single company pulling back.
| Assignee | Recent year | YoY |
|---|---|---|
| Bell Helicopter Textron Inc. | 0 | — |
| Eurocopter (Airbus Helicopters) | 0 | — |
| HILL GRP TECH LTD | 0 | — |
| Textron Innovations Inc. | 0 | — |
| WESTLAND PLC | 0 | — |
| National Aerospace Industries Corporation | 0 | — |
| TECHNOLOGY INTERNATIONAL INC | 0 | — |
| HUDGINS WAYNE A | 0 | — |
Where to take this analysis
The dataset points to a narrow, concentrated field with specific gaps rather than a broad emerging technology.
Map claims against the top five holders
Before drafting in gearing or lubrication subsystems, check the specific claim scope held by the leading assignees rather than assuming open ground.
Explore assignee claims in EurekaTest under-claimed sub-areas
Torque split monitoring, housing crack detection and rotor brake integration carry far fewer records than core gearing claims and may offer more freedom to operate.
Run a white space search in EurekaWatch for the 2025-2026 lag to fill in
Because publication lags filing by about 18 months, treat any read on the most recent two years as provisional until later data cuts confirm it.
Track filing trends in EurekaCommon questions on this field
The ranked set for this field contains 8 assignees covering all 27 records in scope, and the top five of them combined account for 24 of those 27 records, or 88.9%. The leading assignee alone holds 13 records, more than the next four combined, and filing weight drops sharply after the top few names. This means the field is not a level playing field: a small number of established rotorcraft manufacturers and their affiliated entities hold most of the documented claims.
No, based on the tracked figures filing has not grown recently. The peak year in this dataset was 2018 with 13 records, and the tracked three-year comparison shows filings falling from 3 in 2021 to 0 in 2024, a -100% change over that span. 2024 is the most recent year that can be treated as complete, since publication typically lags filing by about 18 months, so 2025 and 2026 figures are still filling in rather than confirming a continued decline.
This Textron Innovations filing, published 2020-04-09, covers an aircraft gearbox with a housing split by a barrier into two compartments, each holding drive system components or gears served by partially independent lubrication subsystems. The design targets continued operation after a partial loss of lubrication rather than preventing the loss itself. Anyone drafting a compartmentalised or dual-subsystem lubrication architecture for a helicopter gearbox should review this filing's specific claim boundaries before finalising claim language.
Within this dataset, IPC subclasses outside the dominant F16H gearing cluster carry far fewer records: F16C shafts, bearings and couplings appears in only 2 of 27 records, and G01H vibration measurement and H02K electric motors each appear in just 1. Practically, this points toward torque split monitoring, housing crack detection, rotor brake integration and chip detector signal processing as areas with comparatively thin documented claim coverage. That thinness does not guarantee freedom to operate, since coverage can exist outside this specific search string, but it is a reasonable starting point for a deeper prior art search.
US5210704A, covering prognosis and diagnostics for helicopter gearbox failure and wearout prediction, carries 788 citations in this corpus, dramatically ahead of the next most-cited record at 72. High citation counts inside a searched corpus tend to favour older filings simply because they have had more time to accumulate references from later work, so this figure should be read as a measure of foundational influence on gearbox health-monitoring approaches rather than as a sign the technology is still cutting-edge today.
Research Helicopter Main Gearbox and Drive Train in depth with Eureka
Go past this page: query the whole helicopter main gearbox and drive train corpus yourself, in your own scope.
Every answer comes back with patent numbers you can open.
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.