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Flavell Evan R: Proportioned resistance exercise servo system. Owen Wickersham & Erickson, November 19, 1974: US3848467 (98 worldwide citation)

A proportional resistance exercise servo device. User interfacng means is connected to a drive shaft so that the user applies force to said drive shaft and vice versa. The device applies braking force to the drive shaft as it is rotated in a first direction by user-exerted force on the interfacing m ...


2
Flavell Evan R: Proportioned resistance exercise servo system. Owen Wickersham & Erickson, March 4, 1975: US3869121 (87 worldwide citation)

A proportional resistance exercise servo device. User interfacing means is connected to a drive shaft so that the user applies force to said drive shaft and vice versa. The device applies braking force to the drive shaft as it is rotated in a first direction by user-exerted force on the interfacing ...