Prior art — US Patent 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:

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.

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.

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.

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.

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.

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.

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.

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.