Reciprocating Compressor Gear Patents: Leaders & White Space 2026
- Filing has cooled since 2019. The peak year was 2019 at 44 filings, and the 2022 midpoint of 33 sits below that, with the trend flat to declining into the most recent years.
- F04B dominates the claim space. 661 of 1,037 records sit in positive-displacement pump subclass F04B, meaning most crank and drive train claims are anchored to pump architecture rather than engine or refrigeration contexts.
- Filing is fragmented, not consolidated. Recent-year momentum across the named assignees shows zero new filings in the latest year for every one of the top co-filing pairs, pointing to a long tail rather than an active leader.
Filing growth compares 2021 (24 records) with 2024 (27) — 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 1,037 records in scope (CR5), not by the ranked leaders only.
What this landscape covers
This landscape tracks patent families where crank mechanism, drive train design or motion conversion mechanism claims intersect with reciprocating or piston compressor bodies. The search spans 2015 through the 2026-07-31 data cut-off, capturing 1,037 published records across eight IPC subclasses, from positive-displacement pumps (F04B) through to rotary-piston machines (F01C).
Because publication typically lags filing by around 18 months, the most recent one to two years in any trend line will understate actual filing activity. The picture below should be read with that lag in mind, particularly when judging whether 2025 and 2026 represent a real slowdown or simply incomplete data.
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Filing trends and technology composition
Two views of the same 1,037-family dataset: how filing volume has moved year over year, and how those filings distribute across the IPC subclasses that touch crank and drive train mechanisms.
A peak in 2019, then a plateau
Filings rose from 7 in 2017 to a peak of 44 in 2019, then settled to a midpoint of 33 in 2022. The trajectory since is flat to declining rather than growing, which for a mechanical subsystem this mature is consistent with claim space that is already well-populated rather than newly opening.
Pump architecture carries most of the claim weight
F04B (positive-displacement pumps) accounts for 661 of 1,037 records, more than six times the next largest subclass. F16J (pistons, seals & gaskets) and F02B (internal-combustion engines) trail well behind, and the smaller subclasses — F04C, F25B, F01B, F01C — each sit in the 53-67 record range, suggesting adjacent mechanism types are documented but nowhere near as densely claimed.
Shares are the percentage of the 1,037 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Reciprocating Compressor Gear and Transmission with Eureka
This page is one run against one query. Ask Eureka your own question about reciprocating compressor gear and transmission and every answer comes back with the patent numbers behind it.
Try EurekaThe most-cited prior art in this space
US20050260080A1 — Reciprocating compressor (Hitachi, Ltd., 2005-11-24)
A reciprocating compressor with a low-pressure stage compression part and two high-pressure stage compression parts, each with a plunger and cylinder, arranged coaxially opposite each other on both sides of a shared crank mechanism. The low-pressure stage piston and cylinder sit in the middle, giving a multi-stage layout driven from a single crank.The arrangement of two opposed high-pressure stages straddling a single crank, with the low-pressure stage placed between them, is the specific structural detail most likely to matter to anyone designing a multi-stage crank-driven layout.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US5342176A | Method and apparatus for measuring piston position in a free piston compressor | 319 |
| 2 | US20050120715A1 | Heat energy recapture and recycle and its new applications | 296 |
| 3 | US6827351B2 | Scrapper device for a reciprocating compressor piston rod | 272 |
| 4 | US6866950B2 | Methods and apparatuses for gas separation by pressure swing adsorption with partial gas product feed to fuel… | 159 |
| 5 | US6276901B1 | Combination sight glass and sump oil level sensor for a hermetic compressor | 152 |
| 6 | US5496153A | Method and apparatus for measuring piston position in a free piston compressor | 126 |
| 7 | US20080155985A1 | Heat Energy Recapture And Recycle And Its New Applications | 108 |
| 8 | US5772410A | Linear compressor with compact motor | 101 |
| 9 | US20020127442A1 | Methods and apparatuses for gas separation by pressure swing adsorption with partial gas product feed to fuel… | 85 |
| 10 | US6216462B1 | High efficiency, air bottoming engine | 75 |
Citation counts are drawn from within this searched corpus and favour older filings that have had more time to accumulate citations — treat them as a measure of influence on later filers, not as a signal of current commercial relevance.
Each row carries its publication number; clicking a row searches Eureka by that number.
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Browse MCP servers →What the numbers say about where this field stands
Three read-outs from the dataset that matter more for filing strategy than the raw counts alone.
Growth has plateaued since the 2019 peak
The subject matter grew steadily through the late 2010s, peaked at 44 filings in 2019, and has not returned to that level since — the 2022 midpoint of 33 sits below peak, and later years trend flat or down even allowing for publication lag.
Pump-body claims dominate the mechanism space
Nearly two-thirds of all records sit in F04B, positive-displacement pumps. Engine-context filings (F02B, 100 records) and bearing/coupling filings (F16C, 67 records) are present but comparatively thin, which narrows where a freedom-to-operate search needs to focus first.
Filing activity concentrates in three jurisdictions
The United States, the European Patent Office and Japan account for the bulk of receiving-office activity, with WIPO/PCT, Austria and Germany forming a second tier. This spread suggests the technology is filed where compressor manufacturing and OEM supply chains are concentrated, not filed opportunistically across many small markets.
Collaboration is limited and mostly zero-momentum now
Only 10 co-assignee pairs appear across the dataset, and the strongest pairs — including recurring rail-research and steel-industry partnerships — show zero filings in the most recent year. Recent-year momentum across every listed assignee reads as zero, consistent with a field where activity has dispersed rather than consolidated around active partnerships.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to reciprocating compressor gear and transmission, with the prior art for and against each one.
Who is filing, and where the gaps sit
The assignee list is a long tail rather than a concentrated leaderboard, and the recent-year momentum figures show that tail has gone quiet across the board.
No assignee is currently active by this measure
Every named assignee in the recent-momentum data — including Kobe Steel, Continental Reifen Deutschland, and Nuovo Pignone — shows zero filings in the latest year. That is consistent with a field where most substantive crank-mechanism claims were staked out earlier in the window and few new entrants are pushing fresh filings through.
Partnerships are narrow and historical
The strongest co-assignee relationships, each with 4 shared filings, link a steelmaker to a rail-research body rather than linking compressor OEMs to each other. That pattern suggests cross-industry material or component research rather than joint compressor product development.
European filing runs deeper than the top-three suggests
Beyond the US, EPO and Japan totals, Austria and Germany each carry 57 records — a meaningful secondary concentration that points to specific European compressor manufacturers filing directly in national offices alongside EPO routes.
| Assignee | Recent year | YoY |
|---|---|---|
| Kobe Steel, Ltd. | 0 | — |
| Continental Reifen Deutschland GmbH | 0 | — |
| Houdon Thomassen Compressors B.V. | 0 | — |
| Mario Dorin Workshop S.p.A. | 0 | — |
| Nuovo Pignone S.p.A. | 0 | — |
| Nuovo Pignone Holding S.p.A. | 0 | — |
| Matsushita Electric Industrial Co., Ltd. (Japan) | 0 | — |
| Nuovo Pignone Tecnologie S.r.l. | 0 | -100% |
Where to take this analysis
The dataset points to a mature, fragmented field with specific structural claims worth checking before committing engineering time to a new crank or drive train design.
Run a freedom-to-operate check on F04B
With 661 of 1,037 records in this subclass, any new crank or drive train mechanism aimed at a compressor pump body should be checked against F04B prior art first, before ranging into the smaller subclasses.
Explore F04B prior art in EurekaMap the opposed-stage layout claim
The Hitachi filing's coaxial opposed high-pressure stage arrangement around a shared crank is a specific structural detail worth tracing forward and backward through citations before designing a similar multi-stage layout.
Trace citation lineage in EurekaWatch the under-claimed branches
Seal wear compensation and refrigeration-duty motion conversion sit in visibly thinner subclasses than the F04B core — a reasonable place to look for claim room rather than contested ground.
Search white space in EurekaCommon questions on this landscape
This dataset identifies 1,037 published patent families filed between 2015 and mid-2026 where crank mechanism, drive train design or motion conversion mechanism claims intersect with reciprocating or piston compressor bodies. The true figure is somewhat higher because publication typically lags filing by around 18 months, so the most recent one to two years are undercounted. Most of these records sit within the F04B positive-displacement pump subclass rather than being spread evenly across compressor-adjacent technology.
Filing peaked at 44 records in 2019 and has not returned to that level since, with the 2022 midpoint sitting at 33. The trend from there is flat to declining, though the very latest years should be read cautiously given publication lag. Overall this reads as a mature field where core mechanism claims were staked out earlier in the period rather than one experiencing fresh growth.
The assignee base is a long tail rather than a concentrated set of leaders — no single company holds a dominant share of the 1,037 families. Firms named in the co-assignee and momentum data include Kobe Steel, Continental Reifen Deutschland, Houdon Thomassen Compressors, Nuovo Pignone and Nuovo Pignone Tecnologie, but every one of them shows zero filings in the most recent year on record. That pattern points to dispersed historical activity rather than an active current leader.
The clearest under-claimed branches sit in subclasses well below the F04B core, including F01B, F01C, F04C and F25B, each in the 53-67 record range against F04B's 661. Within those, specific structural details such as plunger-to-cylinder seal wear compensation, multi-stage crank load balancing, and refrigeration-duty motion conversion mechanisms appear thinly claimed. A first claim in these areas should target a specific structural configuration rather than a broad functional description, since the broad ground is already occupied.
This Hitachi filing from 2005 claims a specific multi-stage layout: a low-pressure compression stage positioned between two high-pressure stages, each with its own plunger and cylinder, arranged coaxially opposite each other on both sides of a single shared crank mechanism. Anyone designing a compressor with that specific opposed, coaxial multi-stage arrangement around one crank should check this filing and its citation lineage closely. It does not block single-stage designs, non-coaxial layouts, or designs using separate crank mechanisms per stage.
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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.