Whiteman Industries v. Allen Engineering

I. Executive Summary and Procedural Information

• Parties & Counsel:
  • Plaintiff: Whiteman Industries, Inc. (Idaho)
  • Defendant: Allen Engineering Corporation (Arkansas)
  • Plaintiff’s Counsel: Dykas & Shaver, LLP
• Case Identification: 1:00-cv-00257, D. Idaho, 05/12/2000
• Venue Allegations: Venue is alleged to be proper based on Defendant transacting business in the District of Idaho or committing acts of infringement within the district.
• Core Dispute: Plaintiff alleges that Defendant’s power trowel devices infringe a patent related to hydraulically controlled steering systems for such machines.
• Technical Context: The technology concerns ride-on power trowels used for finishing large concrete surfaces, specifically focusing on systems that use proportional hydraulic pressure to steer the machine.
• Key Procedural History: The complaint alleges that Plaintiff provided Defendant with notice of infringement prior to filing the lawsuit.

Case Timeline

Date	Event
1997-01-23	U.S. Patent No. 5,816,740 Priority Date (Filing)
1998-10-06	U.S. Patent No. 5,816,740 Issued
2000-05-12	Complaint Filed

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

• Patent Identification: U.S. Patent No. 5,816,740, Hydraulically Controlled Steering for Power Trowel, issued October 6, 1998.

U.S. Patent No. 5,816,740 - Hydraulically Controlled Steering for Power Trowel

The Invention Explained

• Problem Addressed: The patent describes prior art power trowels with mechanical steering linkages as causing significant operator fatigue and lacking the fine control needed for different conditions, such as wet versus hard-curing concrete (’740 Patent, col. 2:30-35, col. 2:58-62). Existing hydraulic systems were described as being of an "on or off" type, resulting in rotors that were either fully tilted or fully flat, which was not acceptable for precise maneuvering (’740 Patent, col. 3:15-24).
• The Patented Solution: The invention proposes a steering system using hydraulic cylinders to tilt the trowel’s rotor assemblies. The key innovation is the use of proportional pressure output control valves, which allow an operator to deliver hydraulic fluid at "variably selectable but constant pressures" (’740 Patent, Abstract). This enables fine, proportional adjustments to the rotor tilt, providing more intuitive and adaptable steering control compared to the abrupt, all-or-nothing control of prior systems (’740 Patent, col. 3:30-45). Figure 4 of the patent, attached as Exhibit A, provides a schematic front view illustrating the interconnection of the rotor assemblies (30, 32) and hydraulic cylinders (44, 46, 48) that implement this solution (Compl., Ex. A).
• Technical Importance: This approach provided a method for precise, low-pressure steering adjustments suitable for high-speed operation on hard concrete, while also allowing for high-force, maximum-tilt maneuvers needed at slow speeds on soft concrete or for repositioning the machine (’740 Patent, col. 7:26-34).

Key Claims at a Glance

The complaint asserts "the claims" of the ’740 patent without specifying which are asserted (Compl., WHEREFORE, ¶ B). The patent contains two independent claims, 1 and 3.

Independent Claim 1:

• A self propelled power trowel, for finishing a concrete surface, which comprises:
• rigid frame means adapted to be disposed over said concrete surface, said rigid frame means having a front and a rear and defining a centerline from front to rear;
• engine means for powering said power trowel attached to the frame means;
• a pair of rotor assemblies for frictionally contacting said concrete surface and supporting said frame means thereabove, tiltably connected to the frame means and operably connected to the engine means;
• at least three dual action hydraulic cylinders, with one interconnected between the frame and each rotor for tilting each rotor toward/away from the centerline, and a third interconnected to one rotor for fore-and-aft tilting;
• a hydraulic pump, operatively connected to the engine and hydraulic cylinders; and
• means for selectively delivering hydraulic fluid from the hydraulic pump to each of the dual action hydraulic cylinders at variably selectable pressure.

Independent Claim 3:

• A self propelled power trowel, for finishing a concrete surface, which comprises:
• rigid frame means, engine means, and a pair of rotor assemblies as in Claim 1;
• at least three pairs of single action hydraulic cylinders, arranged similarly to the dual action cylinders in Claim 1;
• a hydraulic pump, operatively connected to the engine and hydraulic cylinders; and
• means for selectively delivering hydraulic fluid from the hydraulic pump to each of the single action hydraulic cylinders at variably selectable pressure.

III. The Accused Instrumentality

Product Identification

The complaint does not identify any specific accused products by name. It refers generally to "devices which infringe" the ’740 Patent that are made, used, offered for sale, or sold by Defendant Allen Engineering (Compl. ¶7).

Functionality and Market Context

The complaint does not provide any description of the accused devices' specific functionality, features, or market position. Based on the patent-in-suit, the accused devices are presumably ride-on power trowels for finishing concrete.

IV. Analysis of Infringement Allegations

The complaint makes general allegations that Defendant's devices infringe the ’740 Patent but does not provide specific factual allegations mapping the features of any accused device to the limitations of the asserted claims (Compl. ¶¶ 7-9). The complaint does not contain or reference a claim chart, and its allegations are limited to reciting the statutory language for infringement. As a result, a detailed element-by-element analysis of the infringement allegations is not possible based on the provided complaint.

No probative visual evidence provided in complaint.

V. Key Claim Terms for Construction

The complaint does not provide sufficient detail to identify specific infringement disputes that would turn on claim construction. However, based on the patent's description, the following terms from the independent claims and their dependent claims may be central to the case.

• The Term: "means for selectively delivering hydraulic fluid... at variably selectable pressure" (Claim 1); "proportional pressure output control valves" (Claim 2).

  • Context and Importance: This "means-plus-function" limitation, and the structure disclosed to perform it ("proportional pressure output control valves"), is the core of the invention. The patent distinguishes itself from prior art "on or off" systems (’740 Patent, col. 3:15-20). The scope of this term will likely determine whether the accused devices, which may use different valve technologies, fall within the claims. Practitioners may focus on this term because the definition of "proportional" and "variably selectable" is critical to differentiating the invention from prior art.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The specification suggests that the invention is not limited to a specific embodiment, stating that while the preferred embodiment uses certain components, the invention "may be variously embodied to practice within the scope of the following claims" (’740 Patent, col. 7:42-45).
    • Evidence for a Narrower Interpretation: The specification repeatedly links the invention to "proportional pressure output control valves" and discloses specific pressure ranges, such as 5 to 200 pounds for control and 225 to 275 pounds from the pump, which could be argued to limit the scope of the claims (’740 Patent, col. 4:42-54). The abstract also explicitly names "proportional pressure output control valves" as the mechanism.

• The Term: "dual action hydraulic cylinders" (Claim 1) vs. "single action hydraulic cylinders" (Claim 3).

  • Context and Importance: The patent includes independent claims covering both dual-action and single-action cylinder configurations. The specification notes that "the same results may be achieved utilizing paired single action cylinders" instead of dual-action ones (’740 Patent, col. 5:53-55). The specific type of cylinder used in the accused devices will determine which independent claim (1 or 3) is relevant.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The patent itself treats the two cylinder types as largely interchangeable for achieving the inventive result, suggesting a focus on the overall control system rather than the specific cylinder mechanics (’740 Patent, col. 5:53-55).
    • Evidence for a Narrower Interpretation: The claims explicitly distinguish between the two types, creating separate and distinct scopes of protection. An accused device would need to meet the specific cylinder type recited in the asserted claim.

VI. Other Allegations

• Indirect Infringement: The complaint alleges contributory infringement under 35 U.S.C. § 271(c), stating Defendant sells an apparatus or components thereof knowing them to be especially made or adapted for infringement and not a staple article of commerce (Compl. ¶8). It also alleges induced infringement under 35 U.S.C. § 271(b), though the complaint mistakenly cites § 271(f)(1) (Compl. ¶9). No specific facts, such as instructing users via manuals, are alleged.
• Willful Infringement: The complaint alleges that Defendant "has been, and continues to wilfully and wantonly infringe" (Compl. ¶10). The basis for this allegation appears to be pre-suit knowledge, as the complaint states Plaintiff notified Defendant of the infringement "prior to the commencement of this civil action" (Compl. ¶11).

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

Given the limited detail in the complaint, the initial phase of this case will likely focus on establishing the basic facts of the dispute before moving to technical arguments. The central questions are:

1. An evidentiary and pleading question: Which specific products of Allen Engineering Corporation are accused of infringement? The complaint's failure to identify any accused instrumentality will need to be resolved before any substantive analysis of infringement can occur.

2. A technical and definitional question: Assuming an accused product is identified, does its hydraulic control system operate by providing "variably selectable pressure" through "proportional... valves" as described and claimed in the ’740 Patent, or does it use a fundamentally different, non-infringing control mechanism (e.g., a non-proportional, "on-off," or flow-control system)?

3. A claim scope question: What is the scope of the "means for... delivering hydraulic fluid" limitation in the asserted claims? The resolution will depend on whether its scope is limited to the specific "proportional pressure output control valves" disclosed in the specification or can be construed more broadly to cover other valve systems.