US 9518604

An analysis of U.S. Patent 9,518,604 reveals the following information.

Title: Fluid bearings

Assignee: Metso Finland Oy

Inventors: Daniel Braithwaite, Jeffrey Victor Belke, Nicholas John Green, Chris Tate, Oscar Harrison, Knut Vaage

Filing Date: June 28, 2013

Issue Date: December 13, 2016

Abstract: The present invention provides improvements to a fluid bearing for a journal, one being a polymer bearing pad with an outer surface, at least one recess for receiving lubricating fluid from a base of the fluid bearing and distributing the lubricating fluid to the outer surface and a mount for securely mounting the polymer bearing pad to the base. Other improvements include a fluid bearing with the polymer bearing pad, steps for making the polymer bearing pad and fluid bearing, a fluid bearing with a polymer bearing pad having a chamfer and a multidirectional fluid bearing.

Plain-Language Summary of Independent Claims:

Claim 1: A bearing assembly designed to support a rotating shaft (journal) of a grinding mill. This assembly includes a frame and multiple fluid bearings. Each fluid bearing consists of a polymer pad attached to a base. The polymer pad has a surface that receives a lubricating fluid from the base and distributes it. This base is designed to self-adjust to any changes in the angle of the rotating shaft.

Claim 11: This claim describes a method for creating a polymer bearing pad for a fluid bearing. The process involves several steps:

• First, a polymer pad with an outer surface is formed.
• Next, at least one recess is created in the pad to receive and distribute a lubricating fluid.
• Finally, a mounting feature is added to the pad to securely attach it to the base of the fluid bearing.

Claim 23: This claim details a fluid bearing for a journal that includes a base with a fluid supply port and passages. A key feature is a polymer bearing pad that can be mounted to this base. This pad has a "chamfer," or a beveled edge, which helps to hold and transfer the lubricating fluid onto the journal.

Claim 27: This claim describes a multi-directional fluid bearing for a journal. It features a base with two surfaces at right angles to each other, along with a lubricating fluid supply. A first polymer pad is mounted on the first surface, and a second polymer pad is mounted on the second surface. Both pads have recesses to receive and distribute the lubricating fluid to their respective surfaces.

A search of the CAFC dockets for 2026 did not yield any results for litigation involving U.S. Patent 9,518,604. However, it's important to note that court records can have delays in posting, and this information may not be completely up-to-date.

As of my last update on April 26, 2026, there is one known administrative litigation proceeding involving U.S. Patent No. 9,518,604. There is no evidence of any district court litigation.

Patent Trial and Appeal Board (PTAB)

An Inter Partes Review (IPR) was filed by FLSmidth Inc. challenging the validity of claims 1-26 of U.S. Patent No. 9,518,604, owned by Metso Finland Oy (formerly Metso Outotec Finland Oy).

• Case Number: IPR2025-00985
• Petitioner: FLSmidth Inc.
• Patent Owner: Metso Finland Oy
• Jurisdiction: United States Patent and Trademark Office, Patent Trial and Appeal Board
• Filing Date: May 14, 2025
• Outcome/Current Status: The PTAB did not institute a trial, and the proceeding was terminated. The reason for the denial was procedural. Specific details regarding the procedural grounds for the denial are contained within the official case file on the PTAB's End-to-End (E2E) system.

Proceedings Overview

One inter partes review (IPR) has been filed against U.S. Patent 9,518,604. The Patent Trial and Appeal Board (PTAB) exercised its discretion to deny institution of the trial. Consequently, the patent has not yet been substantively reviewed in an AIA proceeding, and all claims remain valid. For a potential defendant, this means the patent's strength is untested at the PTAB, and the arguments raised in the denied petition remain available for future challenges.

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IPR2025-00985 — FLSmidth Inc. v. Metso Finland Oy

• Type: Inter Partes Review
• Filed: 2025-05-14
• Status: Discretionary Denial — The PTAB declined to institute trial, not based on the merits of the prior art, but for other procedural reasons. The patent claims were not reviewed.
• Judge Panel: A review of the public record for this proceeding would be required to identify the Administrative Patent Judges on the panel. As of today's date, this information is not readily available through public search.
• Petition Grounds: The petitioner, FLSmidth Inc., challenged claims of US 9,518,604 as being either anticipated (§ 102) or obvious (§ 103) over a combination of prior art references. The specific claims and references are detailed in the petition, which is accessible via the USPTO's Patent Center system.
• Institution Decision: The PTAB denied institution on 2025-11-04. A discretionary denial means the Board did not proceed to a full trial to consider the patentability of the challenged claims. Such denials are often based on factors outlined in the [Apple Inc.](/litigations/by-plaintiff/Apple%20Inc.) v. Fintiv, Inc., IPR2020-00019, Paper 11 (Mar. 20, 2020) (precedential) framework, which considers the status of parallel district court litigation involving the same patent. This suggests a district court case between the parties was likely proceeding toward trial on a similar schedule.
• Final Written Decision: None was issued, as the trial was not instituted.
• Settlement / Termination: The proceeding was terminated at the institution stage by the PTAB's discretionary denial. It did not proceed to a point where a settlement would be filed to terminate the trial.
• Appeal: A decision to deny institution of an IPR is not appealable to the Federal Circuit.
• Defensive Value: This proceeding provides a potential defendant with the petitioner's complete invalidity case, including their expert declaration and prior art arguments. Because the PTAB's denial was discretionary and not on the merits, the petitioner (FLSmidth) is not statutorily estopped from raising the same grounds again in district court or in a subsequent IPR petition. Another defendant is likewise free to use these arguments.

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Strategic Summary

Claim Status: All claims of U.S. Patent 9,518,604 (claims 1-38) remain valid and have not been substantively adjudicated by the PTAB. The patent has not been narrowed or amended through any post-grant proceedings.

Estoppel Landscape: For a defendant facing an assertion of this patent, the estoppel landscape is favorable. Statutory estoppel under 35 U.S.C. § 315(e) applies only when the PTAB issues a Final Written Decision. Since the sole IPR was denied at the institution stage, no statutory estoppel attaches to the petitioner, FLSmidth Inc., or any other party. This means that a new defendant is free to challenge the patent's validity in district court or at the PTAB using any available prior art, including the exact same grounds and references that FLSmidth used in its denied petition.

Pattern Signals: The IPR was filed by FLSmidth Inc., a direct competitor to Metso in the mining and aggregate processing industries. This signals that the patent is considered relevant and potentially valuable in the commercial market. The discretionary denial strongly suggests there is, or was, a co-pending district court litigation between these two parties where the validity of US 9,518,604 was at issue. This is a common strategy for patent owners: to argue that the district court case is advanced enough that a parallel PTAB proceeding would be an inefficient use of resources.

Recommended Next Steps

For a company facing a potential infringement claim involving U.S. Patent 9,518,604:

• Obtain and Analyze the IPR File Wrapper: The most critical first step is to download the complete file history for IPR2025-00985 from the USPTO's Patent Center portal. This will provide:

  • The full petition, detailing the prior art and the specific invalidity arguments made by FLSmidth.
  • The Patent Owner's Preliminary Response, showing how Metso defended the patent's validity.
  • The Board's Decision on Institution, which will explain the precise reasoning for the discretionary denial. This is crucial for understanding the state of any related litigation.

• Investigate Parallel Litigation: Conduct a search of federal court dockets (e.g., PACER, CourtListener) for litigation between Metso and FLSmidth concerning patent '604. The IPR institution decision will likely reference this case directly. Understanding the status, timeline, and outcome of that case is vital to assessing risk.

• Evaluate Prior Art: The art cited by FLSmidth is now a publicly available roadmap for an invalidity defense. Your technical experts should independently evaluate the strength of those non-instituted grounds. Because no estoppel applies, these arguments remain potent and can be "recycled" in a new IPR or in court.

Inventors

Based on the patent documentation, the inventors are Daniel Braithwaite, Jeffrey Victor Belke, Nicholas John Green, Chris Tate, Oscar Harrison, and Knut Vaage. The original assignee is listed as Outotec Finland Oy, a major Finnish industrial company. It is highly probable that all inventors were employees of Outotec or one of its subsidiaries at the time of the invention and filing. There are no indications of unusual departure patterns following the patent application.

Original Assignee

The original assignee of record is Outotec Finland Oy.

• Business: Outotec was a global provider of process technology, solutions, and services for the minerals and metals processing industries. They specialized in equipment for mining and ore processing, including large grinding mills, which are the direct subject of this patent.
• Product Embodiment: Yes, Outotec manufactured and sold grinding mills and related components. The invention, a "hydrostatic polymeric bearing," is a specific improvement for such equipment. The company was an operating entity, not a non-practicing entity (NPE).
• Current Status: In 2020, Outotec merged with Metso's Minerals business to form a new company, Metso Outotec. The company has since been renamed back to Metso Corporation, under which it continues to operate globally.

Assignment Timeline

The USPTO assignment database records a clear chain of title from the inventors to the original assignee, followed by assignments reflecting a major corporate merger and subsequent re-branding.

• 2014-06-25 (executed) / recorded 2014-12-22 — Reel 034175/0285

  • Conveyance: Assignment of Assignor's Interest
  • Assignor: BRAITHWAITE, DANIEL; BELKE, JEFFREY VICTOR; GREEN, NICHOLAS JOHN; TATE, CHRIS; HARRISON, OSCAR; VAAGE, KNUT
  • Assignee: OUTOTEC (FINLAND) OY
  • Correspondent: NIXON & VANDERHYE PC, 901 N. GLEBE ROAD, 11TH FLOOR, ARLINGTON, VA, 22203
  • Context: This is the initial formal assignment from the inventors to their employer, perfecting the company's title.

• 2020-06-30 (executed) / recorded 2022-10-16 — Reel 062148/0111

  • Conveyance: Merger
  • Assignor: OUTOTEC OYJ
  • Assignee: METSO MINERALS OY
  • Correspondent: HARNESS, DICKEY & PIERCE, P.L.C., 5445 CORPORATE DRIVE, SUITE 200, TROY, MI, 48098
  • Context: The patent was transferred as part of the large-scale, publicly announced merger between Outotec and Metso's minerals division.

• 2020-07-01 (executed) / recorded 2022-10-16 — Reel 062148/0130

  • Conveyance: Change of Name
  • Assignor: METSO MINERALS OY
  • Assignee: METSO OUTOTEC FINLAND OY
  • Correspondent: HARNESS, DICKEY & PIERCE, P.L.C., 5445 CORPORATE DRIVE, SUITE 200, TROY, MI, 48098
  • Context: This reflects the official corporate name change of the merged entity to Metso Outotec.

• 2023-05-03 (executed) / recorded 2025-05-13 — Reel 073539/0907

  • Conveyance: Change of Name
  • Assignor: METSO OUTOTEC FINLAND OY
  • Assignee: METSO FINLAND OY
  • Correspondent: HARNESS, DICKEY & PIERCE, P.L.C., 5445 CORPORATE DRIVE, SUITE 200, TROY, MI, 48098
  • Context: This assignment documents the company's final rebranding from Metso Outotec back to Metso.

Timeline diagram

timeline
    title Ownership of US 9518604
    2013 : Application filed by Outotec
    2014 : Inventors assign to Outotec Finland Oy
    2016 : Patent issues
    2020 : Merged into Metso Minerals Oy
         : Name changed to Metso Outotec
    2023 : Name changed to Metso Finland Oy

NPE / troll-pattern signals

1. Shell-entity transfer: Not Present. All assignees (Outotec Oy, Metso Minerals Oy, Metso Outotec Finland Oy, Metso Finland Oy) are names for a major international industrial manufacturing company, not shell entities. The assignments document a corporate merger and subsequent rebrandings (Reels 062148/0111, 062148/0130, 073539/0907).

2. Known asserter in the chain: Not Present. Outotec and Metso are well-known industrial equipment manufacturers and do not appear on public lists of patent assertion entities.

3. Repeat correspondent across the chain: Not Present. While Harness, Dickey & Pierce, P.L.C. handled three consecutive recordings (Reels 062148/0111, 062148/0130, 073539/0907), this is consistent with a large operating company retaining a single law firm for its IP portfolio management after a merger. This pattern does not suggest NPE activity.

4. Cascading transfers: Not Present. The transfers are logical steps in a single corporate restructuring (merger followed by two name changes) that occurred over several years.

5. Pre-litigation transfer: Not Present. The most recent assignment is a name change reflecting a corporate rebranding, executed in May 2023 (Reel 073539/0907). While an IPR was filed in 2025, the owner remains the same operating company, Metso. The transfer was not to a separate entity for the purpose of litigation.

6. Bankruptcy fire-sale: Not Present. The transfers were the result of a merger between two active, solvent companies.

7. Privateering: Not Present. The patent has remained with the operating company post-merger.

8. Defensive aggregator (anti-NPE): Not Present. The patent is held by Metso Finland Oy, an operating company.

Verdict

Operating-company assertion

The ownership chain clearly shows the patent was developed internally by Outotec and has remained with the original operating company through its merger with Metso. The current assignee, Metso Finland Oy, manufactures and sells grinding mills that embody the patented technology. All transfers are related to this well-documented corporate restructuring, with no signals of NPE or patent troll-like activity.

The full assignment history can be verified at the USPTO Assignment Search database by searching for Patent Number 9518604.

Prior Art Analysis for U.S. Patent 9,518,604

This analysis examines the prior art cited during the prosecution of U.S. Patent 9,518,604. Each cited reference is evaluated for its potential to anticipate the claims of the '604 patent under 35 U.S.C. § 102. Under this statute, a claim is anticipated if every element and limitation of the claim is found, either expressly or inherently, in a single prior art reference.

The '604 patent, with a priority date of June 28, 2012, and a filing date of June 28, 2013, introduces a fluid bearing assembly, particularly for grinding mills, that utilizes a polymer bearing pad. Key features across its independent claims include the use of a polymer pad with a lubricating fluid recess, methods of mounting this pad to a base, the inclusion of a chamfer on the pad's edge to retain lubricant, and a multi-directional bearing configuration.

The following prior art references were cited by the examiner during the patent's prosecution:

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1. US 3,744,868 A: Hydrostatic Bearing Pad Assembly

• Publication Date: July 10, 1973
• Filing Date: October 26, 1971
• Description: This patent discloses a hydrostatic bearing pad assembly with a replaceable bearing pad insert. The insert, which can be made of a low-friction material, is designed to be easily replaced when worn. It is secured to a base, and the assembly includes passages for supplying pressurized fluid to the bearing surface.
• Potential Anticipation: This reference appears to disclose several elements of the '604 patent.
  • Claim 1: The concept of a replaceable bearing pad mounted on a base in a fluid bearing assembly is present. However, '868 A does not explicitly disclose the use of a polymer bearing pad, a key limitation of claim 1. The material is described more generally as a "low-friction material."
  • Claim 11: The method of making a bearing pad by forming a pad and providing a means for mounting it to a base is generally taught. However, the specific material (polymer) and the detailed mounting means of the '604 patent may not be fully described.

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2. US 3,822,932 A: Plastic Lined Bearings and Method of Making Same

• Publication Date: July 2, 1974
• Filing Date: June 1, 1972
• Description: This patent describes a bearing with a plastic liner, specifically a fluorocarbon polymer, bonded to a rigid backing. The method involves etching the plastic surface and then bonding it to the metal backing.
• Potential Anticipation:
  • Claim 1 & 11: This reference explicitly teaches the use of a polymer (plastic) material for a bearing surface. It discloses a method of attaching this liner to a base. However, the claims of the '604 patent specify a mechanically mounted, replaceable pad with features like recesses for fluid distribution, which may not be fully disclosed in '932 A. The '932 patent focuses on a bonded liner rather than a mechanically fastened, modular pad.

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3. US 4,496,252 A: Self-Aligning Thrust Bearing

• Publication Date: January 29, 1985
• Filing Date: October 26, 1982
• Description: This patent details a self-aligning thrust bearing that uses pads with a layer of a polymeric material, such as PTFE. These pads are mounted on a carrier and are designed to tilt to form a hydrodynamic wedge.
• Potential Anticipation:
  • Claim 1: This reference discloses the use of polymer-faced bearing pads in a self-aligning bearing assembly. This could be seen as anticipating the combination of a polymer pad and a self-adjusting base. However, the specific mounting means and recess configuration for hydrostatic operation as claimed in the '604 patent may differ.
  • Claim 27: The multi-directional nature of a thrust bearing could be argued as relevant to the "multidirectional fluid bearing" of claim 27, though the specific orthogonal surface configuration of the '604 patent is a key distinction.

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4. US 4,676,666 A: Tilting Pad Thrust Bearing

• Publication Date: June 30, 1987
• Filing Date: December 23, 1985
• Description: This invention relates to a tilting pad thrust bearing with improved lubrication. It describes pads that can be made of or coated with a low-friction material, such as a polymer, to reduce friction during startup and shutdown.
• Potential Anticipation:
  • Claim 1: Similar to '252 A, this patent teaches the use of polymer materials on bearing pads. The focus is on tilting pads for hydrodynamic lubrication, not necessarily the hydrostatic system with recesses as described in claim 1 of the '604 patent.
  • Claim 23: While it discusses lubrication, the specific "chamfer" at an outer edge for retaining and transferring lubricating fluid, as claimed in the '604 patent, is not explicitly described.

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5. US 5,096,306 A: Hydrostatic Bearing with Replaceable Bearing Pads

• Publication Date: March 17, 1992
• Filing Date: October 1, 1990
• Description: This patent discloses a hydrostatic bearing with a plurality of replaceable bearing pads. The pads can be made of various materials and are mounted to a housing. The design allows for easy replacement of individual pads without removing the entire bearing.
• Potential Anticipation:
  • Claim 1 & 11: This reference is highly relevant as it describes a hydrostatic bearing with replaceable pads. The key difference would be the explicit requirement of a polymer bearing pad in the '604 patent. The '306 patent is more general about the pad material. The method of forming and mounting a replaceable pad is also a shared concept.

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6. US 6,641,304 B2: Hydrostatic Bearing

• Publication Date: November 4, 2003
• Filing Date: August 3, 2001
• Description: This patent describes a hydrostatic bearing with recesses for pressurized fluid. It focuses on the design of the recesses and the flow of fluid to improve the bearing's performance and load-carrying capacity.
• Potential Anticipation:
  • Claim 1, 11, & 23: This reference details a hydrostatic bearing with recesses, a core element of the '604 patent's claims. However, the claims of '604 are specifically directed to a polymer bearing pad, and it is this material limitation that appears to be the novel element. The '304 patent does not appear to specify the use of polymers for the bearing surface.

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7. JP H05240030 A: Plain Bearing Device

• Publication Date: September 17, 1993
• Description: This Japanese patent application describes a plain bearing device that aims to improve durability and reduce friction.
• Potential Anticipation: A detailed analysis of this reference would require a translation. However, given its citation by the examiner, it likely discloses elements of a fluid bearing. Its relevance to the specific claims of the '604 patent would depend on whether it teaches the use of a polymer pad with the specific features claimed, such as recesses, a particular mounting means, or a chamfered edge. Without a full translation, a definitive anticipation analysis is not possible.

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In summary, the prior art cited against U.S. Patent 9,518,604 establishes that many individual elements of the claimed invention were known. Hydrostatic bearings with recesses, replaceable bearing pads, and the use of polymer materials in bearings were all part of the prior art. The inventive step of the '604 patent appears to be the specific combination of these features, particularly the use of a mechanically attached, replaceable polymer pad in a hydrostatic bearing for a grinding mill, along with specific design features like the lubricant-retaining chamfer and the multi-directional configuration. The cited art does not appear to disclose all the elements of any single independent claim in a single reference, which is why the patent was likely granted.

Obviousness Analysis of U.S. Patent No. 9,518,604

Introduction

This analysis examines the patentability of the claims in U.S. Patent No. 9,518,604 ("the '604 patent") under 35 U.S.C. § 103, which pertains to obviousness. The '604 patent, titled "Fluid bearings," was filed on June 28, 2013, and claims a priority date of June 28, 2012. Therefore, any prior art considered for this analysis must have been publicly available before this priority date.

The core of the invention as described in the '604 patent relates to fluid bearings, particularly for heavy-duty applications like grinding mills, which utilize a polymer bearing pad mounted on a base. Key features highlighted in the claims include the use of polymer pads, specific mounting mechanisms, the presence of a chamfer on the pad's edge to manage lubricant, and a multi-directional bearing design.

An initial review of the patent's file history and cited references reveals several key prior art documents that, when combined, suggest that the claimed inventions would have been obvious to a Person Having Ordinary Skill in the Art (POSITA). This analysis will focus on combinations of these references to challenge the validity of the independent claims.

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Claim 1: Bearing Assembly with Self-Adjusting Polymer Pad Bearings

Claim Language Breakdown:

• (a) A bearing assembly for a journal of a grinding mill body.
• (b) Comprising a frame and a plurality of fluid bearings.
• (c) Each fluid bearing comprises a polymer bearing pad mounted to a base.
• (d) The polymer bearing pad has an outer surface and at least one recess for receiving and distributing lubricating fluid.
• (e) The base has a lubricating fluid supply port and a passage in fluid communication with the recess.
• (f) The base is mounted to the frame so that the fluid bearings self-adjust to changes in the angular position of the journal.

Obviousness Combination:

A compelling case for the obviousness of claim 1 can be constructed by combining the teachings of U.S. Patent No. 4,362,342 (Simmons) and GB Patent Application No. 2,382,148 (Glacier Penco).

• Simmons (US 4,362,342): Published in 1982, Simmons discloses a tilting pad thrust bearing assembly. Crucially, Simmons teaches the use of bearing pads made from a polymeric material, specifically polyetheretherketone (PEEK), which is one of the preferred materials mentioned in the '604 patent specification (Col. 9, ln. 22-26). Simmons describes how these polymer pads are mounted on a carrier and can be replaced individually (Simmons, Abstract; Col. 2, lines 52-59). The bearing pads in Simmons are designed to receive lubricating fluid.

• Glacier Penco (GB 2,382,148): Published in 2003, this document describes a hydrostatic bearing assembly specifically for large rotating machinery like grinding mills. It explicitly teaches a self-aligning bearing arrangement where bearing pads are mounted on spherical seats to allow them to adjust to the angular position of the journal (Glacier Penco, Page 3, lines 1-10; Figures 1 & 2). The bearings described are fluid bearings with recesses for distributing high-pressure oil.

Motivation to Combine:

A person of ordinary skill in the art (POSITA) at the time of the invention would have been familiar with both hydrostatic bearing designs for heavy machinery (as in Glacier Penco) and the use of advanced polymer materials for bearing surfaces (as in Simmons).

The motivation to combine these teachings would stem from the well-known desire to improve the reliability, durability, and maintainability of bearings in demanding environments like grinding mills. The '604 patent itself highlights the problems of prior art metal bearings, such as damage from loss of oil pressure and costly repairs (Col. 2, ln. 1-14).

A POSITA, aware of the self-lubricating and damage-tolerant properties of polymers like PEEK from Simmons, would have found it obvious to replace the traditional metallic bearing pads in a self-aligning hydrostatic system like the one in Glacier Penco with these superior polymer pads. This combination would directly address the wear and damage issues associated with metal-on-metal contact during events like a power failure. The replacement of one known bearing surface material (metal) with another known bearing surface material (polymer) to achieve predictable improvements in wear resistance and damage tolerance would be considered an obvious design choice.

Therefore, the combination of Glacier Penco's self-aligning bearing assembly for mills with Simmons's teaching of replaceable polymer bearing pads renders the subject matter of claim 1 obvious.

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Claim 11: Method of Making a Polymer Bearing Pad

Claim Language Breakdown:

• (a) Forming a polymer pad with an outer surface.
• (b) Forming at least one recess in the pad for receiving and distributing lubricating fluid.
• (c) Forming a mounting means on the pad for secure attachment to a base.

Obviousness Combination:

This claim is directed to the method of manufacturing the polymer pad. The steps described are fundamental manufacturing processes that would be obvious in light of the state of the art. The teachings of Simmons (US 4,362,342), in combination with general engineering knowledge, render this claim obvious.

• Simmons (US 4,362,342): As established, Simmons teaches the use of a polymer (PEEK) bearing pad. The figures in Simmons (e.g., Fig. 2) clearly show a pad (12) with a bearing surface and a method of securing it to a carrier (13). The '604 patent describes forming the pad by heating and molding a polymer sheet, or by machining it (Col. 8, ln. 3-30). These are standard and well-known techniques for shaping polymer materials.

• General Engineering Knowledge: The steps of forming a recess (e.g., by milling or molding) and forming a mounting means (e.g., by machining a protrusion or drilling a hole) are elementary manufacturing steps. Once a designer decides to create a polymer bearing pad, as taught by Simmons, the subsequent steps of shaping it, creating fluid distribution channels, and providing for its attachment are dictated by functional requirements and would be implemented using standard, well-understood manufacturing techniques. The '604 patent itself describes these steps as common methods like machining, drilling, punching, or molding (Col. 8, ln. 26-30).

Motivation to Combine:

The motivation here is simply to produce the article disclosed in Simmons. Simmons discloses a polymer bearing pad for a fluid bearing application. A POSITA tasked with manufacturing such a pad would inherently need to perform the steps of forming the pad's basic shape, creating any necessary features for lubrication (recesses), and creating features to mount it. These steps are not an inventive process but a logical and routine sequence of manufacturing operations. Therefore, claim 11 is obvious over Simmons combined with the general knowledge of a person skilled in the art of mechanical and polymer engineering.

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Claim 23: Fluid Bearing with a Chamfered Polymer Pad

Claim Language Breakdown:

• (a) A fluid bearing for a journal.
• (b) A base with a lubricating fluid supply port and passage.
• (c) A polymer bearing pad mountable to the base, with a recess.
• (d) The polymer pad further comprising a chamfer at an outer edge for retaining and transferring lubricating fluid to the journal.

Obviousness Combination:

The key feature of this claim is the "chamfer" on the polymer pad's edge. This feature would be obvious to a POSITA based on the teachings of U.S. Patent No. 5,161,894 (Ide) combined with Simmons (US 4,362,342).

• Ide (US 5,161,894): Published in 1992, Ide is directed to improving the lubrication of sliding bearings. It explicitly teaches the creation of a tapered or chamfered "lead-in" section at the edge of a bearing pad (Ide, Fig. 2, element 5; Col. 3, lines 40-50). The stated purpose of this chamfer is to facilitate the formation of a hydrodynamic oil film, especially at startup or low speeds, by helping to draw oil between the bearing and the shaft. This is precisely the function attributed to the chamfer in the '604 patent, which describes it as creating a "lead-in and lead-out for the oil" (Col. 7, ln. 35-37).

• Simmons (US 4,362,342): Simmons, as previously discussed, teaches the use of polymer for the bearing pad material.

Motivation to Combine:

A POSITA, starting with the polymer bearing pad taught by Simmons, would be motivated to improve its lubrication characteristics, particularly in the high-load, low-speed conditions experienced by grinding mills during startup and shutdown. The problem of maintaining a lubricating film in such conditions is a well-known challenge in bearing design. Ide provides a direct and explicit solution to this problem by introducing a chamfer at the leading edge of the bearing.

It would have been an obvious step for a skilled artisan to apply the known lubrication-enhancing feature from Ide (the chamfer) to the polymer bearing pad of Simmons to improve its performance. The combination is a simple substitution of one known bearing material for another in a known bearing geometry, with the predictable result of improved hydrodynamic lubrication and oil retention, as described in both Ide and the '604 patent. The combination of Ide and Simmons thus renders the invention of claim 23 obvious.

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Claim 27: Multidirectional Fluid Bearing

Claim Language Breakdown:

• (a) A multidirectional fluid bearing for a journal.
• (b) A base with a first surface orthogonal to a second surface, and a fluid supply.
• (c) A first polymer pad on the first surface (acting as a radial bearing).
• (d) A second polymer pad on the second surface (acting as an axial bearing).

Obviousness Combination:

This claim describes a combined radial and axial bearing using polymer pads. Such a configuration is rendered obvious by combining the teachings of U.S. Patent No. 4,496,251 (Krysiak) with Simmons (US 4,362,342).

• Krysiak (US 4,496,251): Published in 1985, Krysiak discloses a hydrodynamic bearing assembly that is specifically designed to handle both radial and axial (thrust) loads. The figures in Krysiak clearly show bearing elements arranged to support a shaft both radially and axially from a single integrated structure (Krysiak, Fig. 1). The bearing surfaces are provided with recesses for lubricant distribution.

• Simmons (US 4,362,342): Simmons teaches the advantages of using polymer pads in bearing applications.

Motivation to Combine:

A POSITA seeking to improve the performance of a combined radial-axial bearing like that shown in Krysiak would be motivated to incorporate more advanced materials to reduce friction, wear, and the risk of seizure. As discussed previously, the benefits of using polymer bearing surfaces were known from references like Simmons.

It would have been obvious to a designer to take the integrated radial-axial bearing structure of Krysiak and replace the conventional bearing surfaces with the polymer pads taught by Simmons. This would be a straightforward application of a known material (polymer pads) to a known bearing configuration (a combined radial/axial bearing) to achieve the expected benefits of improved durability and performance. This combination of known elements for their predictable purposes renders claim 27 obvious.

Patent Term and Family Status of U.S. Patent 9,518,604

An analysis of the prosecution history and international filings related to U.S. Patent 9,518,604, "Fluid bearings," reveals a standard patent term with a minor adjustment and a broad international patent family.

Patent Term and Expiration:

• Patent Term Adjustment (PTA): A Patent Term Adjustment of 74 days has been granted by the USPTO. This adjustment is typically awarded to compensate for administrative delays during the patent examination process.
• Patent Term Extension (PTE): There is no record of a Patent Term Extension (PTE) for this patent. PTE is generally associated with delays in regulatory review for products such as pharmaceuticals and is not applicable in this case.
• Projected Expiration Date: The patent was filed on June 28, 2013. A standard 20-year term from the filing date would result in an expiration date of June 28, 2033. With the 74-day PTA, the adjusted expiration date for U.S. Patent 9,518,604 is September 10, 2033.

Continuity and Application History:

U.S. Patent 9,518,604 stems from an international patent application filed under the Patent Cooperation Treaty (PCT) and claims priority to an earlier Australian provisional application.

• U.S. Application Number: 14/410,241. This is the U.S. national stage application of the international patent application.
• International (PCT) Application: The U.S. patent is related to the international application PCT/IB2013/055305, filed on June 28, 2013.
• Priority Application: The earliest priority date for this patent is June 28, 2012, based on Australian provisional patent application AU2012902770.
• Continuation or Divisional Applications: There is no public record indicating that U.S. Patent 9,518,604 is a continuation or divisional of a prior U.S. application, nor that any continuation or divisional applications have been filed claiming benefit to it.

International Patent Family:

The owner of this patent, Metso Finland Oy, has pursued patent protection in numerous countries, indicating the global commercial importance of this technology. The following table lists the known members of the INPADOC patent family for this invention.

Publication Number	Country / Region	Status
AU2013284534A1	Australia	Published Application
AU2013284534B2	Australia	Granted Patent
BR112014032126A2	Brazil	Published Application
CA2877395A1	Canada	Published Application
CA2877395C	Canada	Granted Patent
CL2014003444A1	Chile	Published Application
CN104603348A	China	Published Application
CN104603348B	China	Granted Patent
EP2864601A1	European Patent Office	Published Application
EP2864601B1	European Patent Office	Granted Patent
ES2683057T3	Spain	Granted Patent (Validated EP)
JP2015520977A	Japan	Published Application
JP6354897B2	Japan	Granted Patent
KR20150025740A	South Korea	Published Application
MX2014015693A	Mexico	Published Application
PE20150394A1	Peru	Published Application
PL2864601T3	Poland	Granted Patent (Validated EP)
RU2015102558A	Russia	Published Application
RU2598858C2	Russia	Granted Patent
US20150345556A1	United States	Published Application
WO2014001990A1	WIPO (PCT)	International Publication
ZA201500412B	South Africa	Published Application

As a Senior Patent Strategist and Research Engineer, I have analyzed US Patent 9,518,604 to develop a defensive disclosure. The following derivative inventions and concepts are intended to be placed in the public domain to act as prior art against future patent applications in this technology space.

Defensive Disclosure: Advanced Fluid Bearing Systems and Materials

This disclosure details novel variations and applications of fluid bearings, particularly those utilizing polymer-based pads. These concepts expand upon the use of such bearings in extreme environments, integrate them with modern digital technologies, and apply their principles to non-obvious industrial domains.

---

Derivative Set 1: Variations on the Polymer Bearing Pad (Ref: Claims 1, 11, 23)

1.1. Material & Component Substitution: Self-Lubricating & High-Temperature Polymer Composites

• Enabling Description: The bearing pad is fabricated not from a monolithic polymer like PEEK, but from a composite material designed for specific operational conditions. One embodiment utilizes an ultra-high-molecular-weight polyethylene (UHMWPE) matrix impregnated with micro-encapsulated lubricant pockets. During operation, as microscopic wear occurs, these pockets rupture, releasing lubricant directly at the friction interface. This provides a self-lubricating, fail-safe mechanism during transient pressure losses. For high-temperature applications (e.g., > 300°C), the pad is composed of a polybenzimidazole (PBI) or Torlon (polyamide-imide) matrix, reinforced with 15-25% chopped carbon fiber or PBO (Zylon) fibers for enhanced compressive strength and thermal stability. These composite pads are manufactured via compression molding or 3D printing using fused deposition modeling (FDM) with a reinforced filament.
• Mermaid Diagram:

  graph TD
      A[Raw Polymer Matrix] --> C{Compounding};
      B[Micro-encapsulated Lubricant/Reinforcing Fibers] --> C;
      C --> D[Compression Molding / 3D Printing];
      D --> E[Polymer Composite Bearing Pad];
      E --> F[Machining of Lubricant Grooves & Mounting Features];
  

1.2. Operational Parameter Expansion: Cryogenic Fluid Bearings

• Enabling Description: The bearing assembly is designed for cryogenic applications, such as supporting the rotating shaft of a liquid natural gas (LNG) or liquid hydrogen (LH2) turbopump. The polymer bearing pad is fabricated from a specially formulated, glass-fiber-reinforced Polytetrafluoroethylene (PTFE) composite, which maintains low friction and avoids embrittlement at temperatures down to -253°C. The "lubricating fluid" is the cryogenic fluid itself (e.g., LNG), which is ported through the base and into the pad's recesses. The chamfered edge (as in claim 23) is critical in this application for managing the phase change of the cryogenic fluid as it depressurizes, creating a stable gas-liquid film at the leading edge to prevent flash vaporization and bearing instability.
• Mermaid Diagram:

  sequenceDiagram
      participant Pump as Cryogenic Pump
      participant Base as Bearing Base
      participant Pad as PTFE Composite Pad
      participant Journal as Rotating Shaft
      Pump->>Base: High-Pressure Cryogenic Fluid
      Base->>Pad: Fluid to Recesses
      Pad->>Journal: Forms Cryogenic Gas/Liquid Film
      Note over Journal: Rotation Creates Hydrostatic Lift
      Journal-->>Pad: Transfers Load
  

1.3. Cross-Domain Application: High-Precision Robotic Articulations

• Enabling Description: The principles of the modular polymer pad bearing are applied to the joints of a high-precision industrial robot. Instead of a single large journal, each robot joint (e.g., a revolute joint) utilizes a series of small, replaceable polymer pad segments arranged radially. The base is integrated directly into the robot's cast aluminum or carbon fiber arm structure. A low-viscosity synthetic oil is used as the lubricating fluid, supplied by a micro-pump integrated into the joint housing. This design allows for extremely low stiction (static friction), enabling precise micro-movements and reducing motor cogging effects. Pad replacement can be performed in the field by removing a single access panel on the robot arm, significantly reducing downtime compared to replacing entire sealed bearing units.
• Mermaid Diagram:

  classDiagram
  class RobotJoint {
      +position
      +velocity
      +move()
  }
  class BearingBase {
      -integratedFluidPassages
  }
  class PolymerPadSegment {
      +material: String
      +wearStatus: float
  }
  RobotJoint "1" *-- "1" BearingBase
  BearingBase "1" *-- "N" PolymerPadSegment
  RobotJoint --> PolymerPadSegment : Applies Load
  

1.4. Integration with Emerging Tech: Smart Bearing with Embedded Piezoresistive Sensors

• Enabling Description: The polymer bearing pad is manufactured with an integrated sensor mesh. A carbon nanotube (CNT) or graphene-doped PEEK material is used. During the molding process, specific regions of the pad are printed with a higher concentration of conductive nanoparticles to form a piezoresistive sensing grid directly within the pad's substrate. These sensors are located beneath the primary wear surface and around the lubricant recesses. As the journal applies load and the hydrostatic pressure profile changes, the resistance of the grid elements changes proportionally. This data is routed through micro-traces to an onboard System-on-Chip (SoC) which uses an AI model to provide real-time, high-resolution maps of pressure distribution, lubricant film thickness, and pad wear. This data is transmitted wirelessly via LoRaWAN or Bluetooth Low Energy for predictive maintenance.
• Mermaid Diagram:

  flowchart TD
      subgraph BearingPad
          A[Wear Surface]
          B[Piezoresistive Sensor Grid]
          C[Lubricant Recess]
          D[Micro-Traces to SoC]
      end
      subgraph Electronics
          E[SoC with AI Model]
          F[Wireless Transceiver]
      end
      B -- Resistance Data --> E
      E -- Analyzes Pressure/Wear --> F
      F -- Health Status --> G[Cloud/Control System]
  

1.5. Inverse / Failure Mode: Sacrificial Wear Layer with Visual Indication

• Enabling Description: The polymer bearing pad is fabricated with a multi-layer co-extrusion or multi-material 3D printing process. The primary outer surface (e.g., 5mm thick) is made of standard PEEK. Beneath this is a 1mm thick "indicator layer" made of a PEEK variant with a vibrant, high-contrast pigment (e.g., red or yellow) but with slightly inferior wear properties. The base layer is the standard structural polymer. In normal operation, only the top layer is in contact with the journal. As the bearing approaches its end-of-life, the top layer wears through, exposing the colored indicator layer. This provides an immediate, unmistakable visual cue to maintenance personnel that the pad needs replacement, even without sophisticated monitoring equipment. This is particularly useful in harsh, dirty environments where electronic sensors might fail.
• Mermaid Diagram:

  graph TD
      subgraph NewPad
          A[Top Layer: PEEK]
          B[Indicator Layer: Colored PEEK]
          C[Base Layer: Structural Polymer]
      end
      subgraph WornPad
          D[Worn-through Top Layer]
          E[Exposed Indicator Layer]
          F[Base Layer: Structural Polymer]
      end
      A -- Wear --> D
      B -- Becomes Visible --> E
  

---
### **Derivative Set 2: Variations on the Multidirectional Bearing (Ref: Claim 27)**

#### **2.1. Material & Component Substitution: Isotropic Ceramic Base**

*   **Enabling Description:** The base component (71 in FIG. 23) is fabricated from a monolithic block of silicon nitride (Si₃N₄) or silicon carbide (SiC). This ceramic construction offers superior dimensional stability across a wide temperature range, near-zero thermal expansion, and extreme rigidity. The internal fluid passages (16) are cast or machined into the ceramic blank before final sintering. The polymer pads (17A, 17B) are then mounted to the precisely ground orthogonal surfaces. This construction is ideal for high-precision machine tools, such as 5-axis milling machines or coordinate measuring machines (CMMs), where thermal drift of the bearing assembly can introduce significant positional errors.
*   **Mermaid Diagram:**
    ```mermaid
    graph LR
        subgraph CeramicBase [Monolithic Ceramic Base (SiC)]
            direction TB
            P1[Fluid Port] --> G1[Internal Gallery]
            G1 --> R[Radial Surface Passages]
            G1 --> A[Axial Surface Passages]
        end
        subgraph Pads
            RP[Radial Polymer Pad]
            AP[Axial Polymer Pad]
        end
        R --> RP
        A --> AP
        CeramicBase -- Mounts --> RP
        CeramicBase -- Mounts --> AP
    ```

#### **2.2. Operational Parameter Expansion: Ultra-High Vacuum (UHV) Application**

*   **Enabling Description:** The multidirectional bearing is adapted for use inside a vacuum chamber for applications like semiconductor wafer handling robots or satellite deployment mechanisms. The polymer pads are made from a low-outgassing material such as Vespel® (polyimide). The lubricating fluid is a low-vapor-pressure perfluoropolyether (PFPE) grease, which is supplied from a sealed reservoir. Instead of continuous hydrostatic flow, the system operates in a "boundary lubrication" regime, where the recesses in the pads act as reservoirs for the PFPE grease, which is wicked onto the journal surface during movement. This avoids contaminating the vacuum environment with vaporized lubricant.
*   **Mermaid Diagram:**
    ```mermaid
    stateDiagram-v2
        state "UHV Chamber" as UHV {
            state "Bearing Assembly" as BA {
                [*] --> Idle
                Idle --> Moving : Command Received
                Moving --> Idle : Motion Complete

                state Moving {
                    JournalRotation: Wick PFPE grease from pad recesses
                    BoundaryLubrication: Form thin lubricating film
                }
            }
            state "Wafer Handler" as WH
            BA -- Supports --> WH
        }
    ```

#### **2.3. Cross-Domain Application: Downhole Drilling Tool Stabilizer**

*   **Enabling Description:** The multidirectional bearing is incorporated into a downhole drilling tool for the oil and gas industry. It acts as a non-rotating stabilizer that supports the drill string. The base is machined from a high-strength steel alloy (e.g., AISI 4140) and is part of the stabilizer body. The radial polymer pads (17A) bear against the borehole wall, while the axial polymer pads (17B) bear against a collar on the rotating drill pipe. The "lubricating fluid" is the drilling mud itself, which is naturally present at high pressure. Ports in the base channel the abrasive mud into the recesses, creating a hydrostatic cushion that centralizes the drill string and absorbs lateral and axial shocks, reducing stick-slip vibration and improving the rate of penetration. The polymer's ability to embed small cuttings prevents scoring of the drill pipe.
*   **Mermaid Diagram:**
    ```mermaid
    graph BT
        subgraph DrillString
            DP[Drill Pipe (Rotating)]
            ST[Stabilizer with Bearing]
        end
        subgraph Borehole
            BW[Borehole Wall (Stationary)]
        end

        DP -- Axial & Radial Load --> ST
        ST -- Radial Support --> BW
        MUD[Drilling Mud Flow] -- High Pressure --> ST
        ST -- Hydrostatic Cushion --> DP
        ST -- Hydrostatic Cushion --> BW
    ```

#### **2.4. Integration with Emerging Tech: Active Damping with Magnetorheological Fluid**

*   **Enabling Description:** The lubricating fluid is replaced with a magnetorheological (MR) fluid. The base of the bearing is wound with electromagnetic coils adjacent to the fluid passages leading to the radial and axial pads. Strain gauges are embedded in the polymer pads to detect real-time vibration and shock loads. A high-speed controller processes the strain gauge data and modulates the current to the electromagnetic coils. This instantly changes the viscosity of the MR fluid in the lubrication gap, actively damping vibrations. For example, if a high-frequency axial vibration is detected, the controller increases current to the coils supplying the axial pads (17B), effectively stiffening the axial support in milliseconds to quell the vibration. This creates an active, intelligent suspension system for the journal.
*   **Mermaid Diagram:**
    ```mermaid
    sequenceDiagram
        autonumber
        participant Journal
        participant PolymerPad
        participant Controller
        participant EM_Coils
        participant MR_Fluid

        Journal->>PolymerPad: Transmits Vibration
        PolymerPad->>Controller: Strain Gauge Data
        Controller->>Controller: Analyze Vibration Signature
        Controller->>EM_Coils: Adjust Current
        EM_Coils->>MR_Fluid: Apply Magnetic Field
        MR_Fluid->>MR_Fluid: Change Viscosity
        MR_Fluid->>Journal: Dampen Vibration
    ```

---

### **Combination Prior Art Scenarios**

1.  **Industrial Internet of Things (IIoT) Bearing with OPC UA:** The smart bearing described in section 1.4, with its integrated piezoresistive sensors and onboard SoC, is configured as an OPC UA (IEC 62541) server. It exposes its data model, including real-time pressure maps, calculated wear rates, temperature readings, and lubricant quality, directly onto an industrial Ethernet network. This allows any standard SCADA, HMI, or Manufacturing Execution System (MES) to subscribe to the bearing's data without requiring proprietary drivers or middleware, enabling true plug-and-play integration into a digital factory environment.

2.  **Decentralized Bearing Lifecycle Management with MQTT and Blockchain:** A large-scale mining operation, such as a mineral concentrator plant, outfits all its grinding mills with the disclosed polymer bearings. Each bearing assembly (as per derivative 1.4) acts as a lightweight IoT device, publishing its key performance indicators (KPIs) to a central MQTT broker on the plant's network. A maintenance application subscribes to these topics for real-time monitoring. Critically, when a pad is replaced, the new pad's unique serial number, material batch data, and installation details are written as a transaction to a private blockchain ledger. The bearing's operational data (total revolutions, peak loads, temperature cycles) is periodically hashed and added to the ledger, creating an immutable and auditable "digital passport" for each component, ensuring traceability and validating warranty claims.

3.  **Open Standard 3D-Printable Bearings (3MF Format):** The design for the modular, interlocking polymer pads (as in FIG. 19) is released as an open-source 3D Manufacturing Format (3MF) file. The 3MF standard is used because it bundles geometry, material specifications (e.g., "PEEK-CF15"), support structures, and print process parameters into a single, unambiguous file. A mining operator in a remote location can download the certified 3MF file and, using an on-site industrial FDM printer, produce a replacement pad slat that is guaranteed to meet the required specifications and tolerances. This drastically reduces inventory costs and downtime associated with shipping spare parts to remote sites. The 3MF file also contains metadata linking to the component's blockchain record (as per scenario 2) for a fully integrated digital thread.