Obviousness

Here is a technical analysis of the obviousness of US patent 6,434,212 under 35 U.S.C. § 103, based on the provided prior art summary.

Obviousness Analysis of US Patent 6,434,212

This analysis evaluates the claims of US Patent 6,434,212 in light of prior art to determine whether the claimed subject matter would have been obvious to a Person Having Ordinary Skill in the Art (PHOSITA) at the time of the invention (priority date October 28, 1998).

A PHOSITA in this field would have a bachelor's degree in electrical or computer engineering, with several years of experience in designing firmware and hardware for portable consumer electronics, and would be familiar with exercise monitoring devices and basic principles of exercise physiology.

I. Analysis of Independent Claim 6 (Found Unpatentable)

Claim 6: A pedometer system with a step counter, a transmitter/receiver pair, and a data processor programmed to calculate distance using a stride length that varies with step rate, where the actual stride length is derived from a range of stride lengths calculated from a range of corresponding stride rates.

Conclusion: Claim 6 is obvious over the combination of US Patent 5,891,042 (Sham) and US Patent 5,976,083 (Livingstone). This conclusion aligns with the Final Written Decision of the PTAB in IPR2017-02012, which was affirmed by the Federal Circuit.

Reasoning:

1. Base Reference (Sham): The Sham patent discloses the fundamental architecture of the claimed system. It teaches a wrist-mounted device with a receiver (for heart rate), a step counter, and a data processor that calculates distance. This establishes the physical framework of the pedometer system recited in claim 6.

2. Missing Element: The critical deficiency in Sham is its method for calculating distance, which uses a single, user-inputted, fixed stride length. Sham does not teach a stride length that varies according to the rate of steps.

3. Secondary Reference (Livingstone): The Livingstone patent explicitly addresses the known problem of inaccuracy in pedometers that use a fixed stride length. Livingstone teaches the precise solution: varying the stride length based on the user's cadence (stride rate). It discloses using a formula or lookup table to correlate different stride rates with different stride lengths to achieve a more accurate distance calculation.

4. Motivation to Combine: A PHOSITA would have been motivated to combine the teachings of Sham and Livingstone for a clear and predictable reason: to improve the performance of the Sham device. The inaccuracy of fixed-stride-length pedometers was a well-known problem in the art. Livingstone provided a known solution to this known problem. Therefore, incorporating Livingstone's cadence-dependent stride length calculation into the hardware system of Sham would have been an obvious and logical step for a skilled artisan seeking to create a more accurate and commercially competitive fitness monitor. The result would be the system of claim 6.

II. Analysis of Independent Claims 2 and 5 (Found Not Unpatentable)

Claim 2: An exercise monitoring device where the processor determines stride length "with reference to a plurality of calibrations that each calculate a stride length as a function of a known stride rate."

Claim 5: An exercise monitoring device where the processor is programmed to "derive the stride length from a range of stride lengths calculated from a range of corresponding stride rates calculated from a plurality of calibration samples."

Conclusion: Claims 2 and 5 are not rendered obvious by the combination of Sham and Livingstone, nor by other combinations of the cited art. This conclusion aligns with the PTAB's decision to uphold these claims in IPR2017-02012.

Reasoning:

The key limitations in these claims are the specific methods of calibration: using a "plurality of calibrations" (Claim 2) or a "plurality of calibration samples" (Claim 5) to derive the stride length.

1. Insufficiency of Sham and Livingstone: While Livingstone teaches the general principle of varying stride length with rate, it does not explicitly teach or suggest the specific method of using multiple, distinct, user-performed calibration runs (e.g., a slow, medium, and fast-paced run over a known distance) to generate a set of personalized data points from which to derive the stride length relationship. A PHOSITA combining Sham and Livingstone would likely implement a system with a generic, pre-programmed curve or lookup table as taught by Livingstone, not necessarily one that guides a user through multiple calibration samples to build a personalized profile.

2. Distinction from Karr and Puma:

   • Karr ('945) teaches measuring each stride directly with ultrasonics, which is a fundamentally different approach from using stride rate as a proxy for stride length derived from calibration.
   • Puma ('394) teaches a calibration process, but it is described as an extensive one requiring 15 or more test runs to build a complex data model. The method claimed in the '212 patent, as described in the specification, involves a simpler process with a few distinct calibration samples. The PTAB was not persuaded that it would have been obvious to modify the extensive Puma method or the generic Livingstone method to arrive at the specific "plurality of calibration samples" approach recited in claims 2 and 5.

Therefore, the specific user-centric, multi-sample calibration process for personalizing the stride-rate-to-stride-length correlation was not taught or suggested by the prior art of record, leaving claims 2 and 5 non-obvious.

III. Analysis of Independent Claim 1

Claim 1: An exercise monitoring device with a strap, step counter, heart rate monitor, and a data processor that calculates distance using a stride length that "varies according to a rate at which steps are counted."

Conclusion: A strong argument exists that claim 1 is obvious over the combination of Sham and Livingstone.

Reasoning:

Claim 1 is broader than claims 2 and 5. It does not include the limiting language requiring a "plurality of calibrations" or "calibration samples." It only requires the core inventive concept of a stride length that varies with the step rate.

1. Combination of Sham and Livingstone: As established in the analysis for claim 6, Sham provides the physical device (strap, step counter, heart rate monitor, processor), and Livingstone provides the functional improvement (varying stride length with rate).
2. Motivation to Combine: The motivation remains the same: to improve the accuracy of the device disclosed in Sham by implementing the known technique from Livingstone. A PHOSITA would have readily combined these teachings to produce the device of claim 1.

While this claim was part of a settled IPR (IPR2017-01058) and thus never adjudicated on the merits by the PTAB, the legal reasoning that successfully invalidated the more specific claim 6 applies with equal or greater force to the broader claim 1.