Nathan E Siegel

US Patent:

44732260, Sep 25, 1984

Filed:

Jun 29, 1982

Appl. No.:

6/393262

Inventors:

Nathan Siegel - Baltimore MD
Douglas A. Browning - Sykesville MD

Assignee:

Baltimore Therapeutic Equipment Company - Baltimore MD

International Classification:

A63B 2300

US Classification:

272132

Abstract:

An electronic ratchet for allowing the application of mechanical resistance to an output shaft in one direction while ratcheting in the opposite direction, which comprises, in combination: (a) an electromagnetically controlled friction brake coupled to an output shaft; (b) provision for controlling the application of DC voltage across the electromagnet, regardless of the direction of rotation; (c) a switch for selectively applying such voltage to obtain resistance to clockwise, counter clockwise, or both directions of rotation; (d) an incremental shaft encoder coupled to the output shaft for determining the direction of shaft rotation; (e) a decoder for decoding the direction of shaft rotation; and (f) an armature through which the output shaft is inserted, the shaft and armature being held as a single rotating unit by opposing keys on the output shaft and the keyways being characterized by a degree of free play equal to the sensitivity of the shaft encoder, whereby the direction of shaft revolution can be determined and compared to the switch setting during such free play.