Obviousness

I understand your request to analyze the obviousness of US patent 8,721,511 under 35 U.S.C. § 103, by identifying combinations of prior art references and motivations to combine them.

However, the provided patent text for US8721511, while listing "Prior art keywords" such as "foot," "wall," "frame," "carriage," and "foot bar," does not include a "References Cited" section or any other specific prior art patent numbers or publications that I can use for this analysis. Without a defined set of prior art references, it is not possible to identify combinations of specific prior art documents that would render the claims obvious under 35 U.S.C. § 103.

To perform a thorough obviousness analysis, one would typically need:

1. A primary prior art reference: This reference would ideally teach most of the elements of a given independent claim (e.g., Claim 1, 11, 20, or 28 of US8721511).
2. Secondary prior art references: These references would teach the remaining elements not found in the primary reference.
3. A motivation to combine: An explanation of why a person having ordinary skill in the art (PHOSITA) would have been motivated to combine the teachings of the primary and secondary references to arrive at the claimed invention, with a reasonable expectation of success. This motivation could stem from various factors, such as:
   • The references being in the same field of endeavor (e.g., exercise equipment).
   • The references addressing the same problem.
   • The claimed invention representing a predictable variation of prior art elements.
   • Common sense or general knowledge in the art.
   • Known design incentives or market demands.

Given the absence of specific prior art references in the provided information, I cannot fulfill the request to identify combinations of prior art references and explain the motivation to combine them. If specific prior art references become available, I would be able to proceed with this analysis.