Daniel C Norton

US Patent:

49340727, Jun 19, 1990

Filed:

Apr 14, 1989

Appl. No.:

7/339198

Inventors:

Raymond M. Fredericksen - Okemos MI
Daniel T. Barry - Ann Arbor MI
Daniel E. Norton - Clackamas OR

Assignee:

Wolverine World Wide, Inc. - Rockford MI

International Classification:

A43B 1318
A43B 1900

US Classification:

36 29

Abstract:

A special sealed heel bladder defining a space divided into a rear heel chamber positioned in the main heel strike area and a front heel chamber. The rear heel chamber comprises about 60 percent of the total volume. The front heel chamber comprises about 40 percent of the total volume. These chambers are divided by a diagonal interior wall at an angle of 35 degrees to a transverse line or plane and having controlled flow orifice means which regulates rate of flow of a viscous liquid from the rear heel chamber to the front heel chamber upon heel strike. The chambers are filled with a mixture of viscous liquid and a gas, typically air. The volume of viscous liquid is greater than the volume of the front heel chamber and preferably is about 80 to 90 percent of the total volume. The front heel chamber has flexible resilient walls allowing limited expansion capacity caused by temporary resilient bulging of the walls, creating a return biasing force by the walls on the liquid because of a greater pressure momentarily created in the front heel chamber by flow thereinto of a greater amount of liquid than the at-rest volume of the front heel chamber. This resilient biasing force causes effective return flow of liquid back to the rear heel chamber when pressure is released from the rear heel chamber during foot roll and toeoff by the runner.