DCT

3:10-cv-00310

Precision Concrete Cutting Inc v. Rifley

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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 3:10-cv-00310, N.D. Cal., 03/15/2010
  • Venue Allegations: Plaintiff alleges venue is proper because Defendants have solicited business and caused injury in the district, and a substantial part of the alleged infringement occurred there.
  • Core Dispute: Plaintiff alleges that Defendants’ concrete saw-cutting services infringe four patents related to methods and apparatuses for removing trip hazards from concrete sidewalks.
  • Technical Context: The technology addresses the removal of trip hazards on sidewalks, often to comply with ADA standards, by using a specialized saw apparatus to create a smooth, angled chamfer on the edge of a raised concrete slab.
  • Key Procedural History: The asserted patents are part of a single family, all claiming priority to the same 2002 application. U.S. Patent No. 7,402,095 was the subject of an ex parte reexamination, resulting in an amended independent claim 1. The complaint alleges that in 2009, Defendants told a mutual customer that Plaintiff’s patents were “worthless” and had been “successfully challenged.”

Case Timeline

Date Event
2002-01-01 Plaintiff begins using "Trip Hazard Removal Specialist" service mark
2002-05-24 Earliest Priority Date for all four Patents-in-Suit
2004-12-07 U.S. Patent No. 6,827,074 Issues
2006-12-05 U.S. Patent No. 7,143,760 Issues
2007-04-10 U.S. Patent No. 7,201,644 Issues
2008-01-01 Approximate start of Defendants' alleged infringement
2008-07-22 U.S. Patent No. 7,402,095 Issues
2009-01-01 Defendants allegedly misrepresent patents to City of San Diego
2010-03-15 Amended Complaint Filed
2011-05-24 Reexamination Certificate for U.S. Patent No. 7,402,095 Issues

II. Technology and Patent(s)-in-Suit Analysis

U.S. Patent No. 7,402,095 - "Method for Removing Trip Hazards in Concrete Sidewalks," issued July 22, 2008.

The Invention Explained

  • Problem Addressed: The patent identifies the problem of uneven sidewalk slabs caused by tree roots or soil settling, which create trip hazards that must be remedied to comply with legislation like the Americans with Disabilities Act (ADA) (’095 Patent, col. 1:5-14, 52-58). Traditional remediation methods like replacing slabs or using macadam for ramps are described as expensive, slow, or unsightly (’095 Patent, col. 1:59-col. 2:10).
  • The Patented Solution: The invention is a method for removing these hazards by making a series of angled, planar cuts with a specialized concrete saw blade mounted on a right-angle grinder (’095 Patent, Abstract). A key feature of the method is that an initial cut creates a "cantilevered ledge" of concrete, which is then deliberately fractured and removed with a tool before subsequent cuts are made to complete a smooth chamfer (’095 Patent, col. 8:1-12). This process is designed to be more efficient than grinding away all the excess material (’095 Patent, col. 2:1-10).
  • Technical Importance: This method purports to offer a faster, less expensive, and more aesthetically pleasing solution for sidewalk repair and ADA compliance compared to prior techniques (Compl. ¶12-13).

Key Claims at a Glance

The complaint alleges infringement of "one or more claims" but does not specify which ones (Compl. ¶26). Independent claim 1, as amended by the Reexamination Certificate US 7,402,095 C1, includes the following essential steps:

  • making a generally planar cut... with a generally circular, generally laminar concrete saw blade that is secured to a hub attached to a rotatably powered output shaft of a handheld right-angle grinder motor...
  • ...creating a cantilevered ledge above the generally planar cut...
  • striking the cantilevered ledge with a tool in order to fracture and remove at least a portion of the cantilevered ledge from the slab whenever an edge of the cantilevered ledge is proximate the hub...
  • ...and continuing the generally planar cut until the cantilevered ledge is severed from the slab.

U.S. Patent No. 7,143,760 - "Method for Removing Trip Hazards in Concrete Sidewalks," issued December 5, 2006.

The Invention Explained

  • Problem Addressed: The patent addresses the same problem as the ’095 Patent: the need for an efficient and effective way to remove trip hazards from uneven concrete sidewalks to meet public access standards (’760 Patent, col. 1:12-25).
  • The Patented Solution: The ’760 patent discloses a method using a specific type of apparatus: a right-angle grinder coupled with a saw blade via a mounting hub that has "no blade attachment hardware projecting below a lower major surface of the blade" (’760 Patent, Abstract; col. 4:9-12). The claimed method involves making a planar cut to create a cantilevered ledge, fracturing that ledge if it is not severed by the cutting action, and continuing with subsequent cuts until the hazard is removed (’760 Patent, col. 3:11-41).
  • Technical Importance: The non-projecting hardware is critical, as it allows the blade to make flush cuts without the hub or screw heads snagging on the concrete surface, enabling the specific multi-pass cutting method (Compl. ¶12; ’760 Patent, col. 5:10-16).

Key Claims at a Glance

The complaint alleges infringement of "one or more claims" (Compl. ¶34). Independent claim 1 includes the following essential elements:

  • providing a generally circular, rotatable concrete saw blade that is coupled to a right-angle grinder motor with a blade-mounting hub having no blade attachment hardware projecting below a lower major surface of the blade;
  • making a planar cut at a desired angle... creating a cantilevered ledge above the planar cut;
  • fracturing and removing at least a portion of the cantilevered ledge... whenever an edge of the cantilevered ledge is proximate the hub; and
  • continuing the planar cut until the cantilevered ledge is severed from the slab.

U.S. Patent No. 7,201,644 - "Apparatus for Removing Trip Hazards in Concrete Sidewalks"

  • Patent Identification: U.S. Patent No. 7,201,644, "Apparatus for Removing Trip Hazards in Concrete Sidewalks," issued April 10, 2007 (Compl. ¶39).
  • Technology Synopsis: This patent claims the cutting apparatus itself, not the method of use. The invention is an apparatus combining a hub and blade for a right-angle grinder, where the blade is attached with countersinking screws so that the screw heads are flush with the blade’s lower surface. This design is what enables the flat, unimpeded cutting action central to the methods claimed in the companion patents (’644 Patent, Abstract).
  • Asserted Claims: "one or more claims"; independent claims are 1, 9, and 14 (Compl. ¶42).
  • Accused Features: The complaint alleges Defendants' services utilize products covered by the patent, implying they use a cutting apparatus with a functionally similar flush-mount blade design (Compl. ¶¶16, 42).

U.S. Patent No. 6,827,074 - "Method and Apparatus for Removing Trip Hazards in Concrete Sidewalks"

  • Patent Identification: U.S. Patent No. 6,827,074, "Method and Apparatus for Removing Trip Hazards in Concrete Sidewalks," issued December 7, 2004 (Compl. ¶47).
  • Technology Synopsis: As the earliest patent in the family, the ’074 patent broadly discloses both the method and apparatus for removing sidewalk trip hazards. It describes the combination of a right-angle grinder, a specialized hub, and a diamond-grit blade attached with flush-mounted screws, and the method of using this apparatus to make progressive chamfer cuts.
  • Asserted Claims: "one or more claims"; independent claims are 1, 6, and 11 (Compl. ¶50).
  • Accused Features: The complaint alleges Defendants' services imitate the patented methods and use a covered apparatus, suggesting their overall process and equipment fall within the scope of the claims (Compl. ¶¶16, 50).

III. The Accused Instrumentality

  • Product Identification: The accused instrumentality is the "concrete 'sawing' or 'saw-cutting'" service offered by Defendants (Compl. ¶16).
  • Functionality and Market Context: The complaint alleges that Defendants began to "imitate Precision's patented methods" and market a competing service (Compl. ¶16). It is alleged that Defendants represent to customers, such as the City of San Diego, that they can "perform the exact same concrete saw cutting service as Precision" (Compl. ¶24). These services are allegedly offered through Defendants' website, which is also accused of using Plaintiff's trademarks to attract customers (Compl. ¶17).
  • No probative visual evidence provided in complaint.

IV. Analysis of Infringement Allegations

The complaint does not specify which claims are asserted or provide detailed infringement contentions. The analysis below is based on the general allegation that Defendants "imitate Precision's patented methods" (Compl. ¶16) and perform the "exact same... service" (Compl. ¶24), mapped to the elements of a representative independent claim for each patent.

'095 Patent Infringement Allegations

Claim Element (from Independent Claim 1, as amended) Alleged Infringing Functionality Complaint Citation Patent Citation
making a generally planar cut... with a... concrete saw blade that is secured to a hub attached to a rotatably powered output shaft of a handheld right-angle grinder motor... Defendants perform a "concrete saw cutting service" that allegedly imitates Plaintiff's patented methods. ¶16, ¶24, ¶26 col. 7:38-50
...creating a cantilevered ledge above the generally planar cut... The allegedly imitated method involves making cuts that would necessarily create an overhanging ledge of concrete. ¶16, ¶24, ¶26 col. 8:1-3
striking the cantilevered ledge with a tool in order to fracture and remove... the cantilevered ledge... whenever an edge of the... ledge is proximate the hub... The allegedly imitated method includes removing the overhanging concrete before it interferes with the cutting hub. ¶16, ¶24, ¶26 col. 8:9-12
...and continuing the generally planar cut until the cantilevered ledge is severed from the slab. The allegedly imitated method involves a multi-pass process to complete the removal of the trip hazard. ¶16, ¶24, ¶26 col. 8:13-20

'760 Patent Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
providing a... concrete saw blade that is coupled to a right-angle grinder motor with a blade-mounting hub having no blade attachment hardware projecting below a lower major surface of the blade; Defendants allegedly use an apparatus capable of performing the "exact same service," which implies use of a similar flush-mount blade assembly. ¶16, ¶24, ¶34 col. 4:9-12
making a planar cut at a desired angle... creating a cantilevered ledge above the planar cut; Defendants' "saw-cutting" service allegedly includes making angled cuts that create an overhanging concrete ledge. ¶16, ¶24, ¶34 col. 7:10-18
fracturing and removing at least a portion of the cantilevered ledge from the slab whenever an edge of the cantilevered ledge is proximate the hub; and The allegedly imitated method includes removing the ledge to allow the cutting to continue unimpeded. ¶16, ¶24, ¶34 col. 7:19-25
continuing the planar cut until the cantilevered ledge is severed from the slab. The allegedly imitated method involves continuing the cut in one or more passes to form a complete chamfer. ¶16, ¶24, ¶34 col. 7:26-28

Identified Points of Contention:

  • Evidentiary Questions: The complaint's allegations are conclusory. A primary point of contention will be factual: what evidence will show that Defendants' actual service practices every step of the asserted method claims? The case will depend heavily on what discovery reveals about the specific tools and techniques used by Defendants.
  • Technical Questions: A key technical question is whether the equipment used by Defendants meets the structural limitations of the apparatus claims (e.g., in the ’644 and ’074 patents) and the preamble of the ’760 method claim, specifically the requirement for a blade with no projecting hardware on its lower surface.
  • Scope Questions: For the ’095 patent, infringement hinges on whether Defendants' method includes "striking the cantilevered ledge with a tool." For the ’760 patent, a question is whether incidental breakage of the ledge by the saw blade itself meets the "fracturing and removing" step, or if a more deliberate, separate action is required.

V. Key Claim Terms for Construction

The Term: "cantilevered ledge" (asserted in '095 and '760 patents)

  • Context and Importance: This term is fundamental to the claimed invention, as the two-step process of creating and then fracturing this ledge is what distinguishes the method from simple grinding. The definition of what constitutes a "ledge" will be critical to determining if Defendants' process infringes.
  • Intrinsic Evidence for a Broader Interpretation: The specification describes the process as creating an "overhanging ledge" (’074 Patent, FIG. 27), which could support a broad interpretation covering any piece of concrete left overhanging a cut.
  • Intrinsic Evidence for a Narrower Interpretation: The patent figures consistently depict a distinct, shelf-like structure created by a clean, planar cut (’074 Patent, FIG. 26, element 2601). This may support a narrower construction requiring a specific geometry rather than any amorphous piece of broken concrete.

The Term: "striking the cantilevered ledge with a tool" ('095 patent, amended claim 1)

  • Context and Importance: This language was added during reexamination and is thus presumptively significant for distinguishing the invention from the prior art. Practitioners may focus on this term because infringement of the ’095 patent will depend entirely on whether Defendants' process includes this specific, active step.
  • Intrinsic Evidence for a Broader Interpretation: The complaint does not provide sufficient detail for analysis of evidence supporting a broader interpretation.
  • Intrinsic Evidence for a Narrower Interpretation: The specification describes this step as "fractur[ing]" the ledge by "hitting it with a hammer or other similar instrument" (’074 Patent, col. 8:9-12). This explicit disclosure of using a separate instrument like a hammer strongly supports a narrow construction that requires an action distinct from the cutting operation itself.

VI. Other Allegations

  • Indirect Infringement: The complaint focuses on allegations of direct infringement by Defendants and their agents (Compl. ¶¶26, 34, 42, 50). It does not plead specific facts to support claims of induced or contributory infringement.
  • Willful Infringement: The complaint alleges that Defendants' infringement was willful based on knowledge of the patents-in-suit (Compl. ¶¶29, 37, 45, 53). This allegation may be supported by the specific factual claim that in 2009, Defendants contacted the City of San Diego and represented that "Precision's patents were worthless and had been successfully challenged 'up north'" (Compl. ¶20). This allegation, if proven, suggests pre-suit knowledge of the patents and potential objective recklessness.

VII. Analyst’s Conclusion: Key Questions for the Case

  • A central issue will be one of evidentiary proof: As the complaint relies on notice pleading, the case will likely turn on whether discovery produces evidence that Defendants' concrete cutting service, as actually performed, contains every element of the asserted claims, especially the specific sequence of creating and then separately fracturing a "cantilevered ledge."
  • A key question will be one of claim scope and amendment: How will the court construe the phrase "striking the cantilevered ledge with a tool," which was added to the ’095 patent during reexamination? The resolution of this issue—specifically, whether it requires a separate tool like a hammer or could be met by other means—may be dispositive for infringement of that patent.
  • A third major question will concern willfulness: The allegation that Defendants actively disparaged the patents to a customer (Compl. ¶20) raises a significant question of fact regarding pre-suit knowledge and intent. The determination of what Defendants knew, when they knew it, and what steps they took in light of that knowledge will be critical to the claim for enhanced damages.