Patent ID: 9744404
Date: 2017-08-29
CPC Classifications: A63B

Claim:
1. A lat pulldown fitness device, comprising: a base, wherein a seat portion, a footrest portion, and a support frame are disposed on the base, with the footrest portion disposed between the seat portion and the support frame; a magnetorheological fluid (MRF) resistance provider disposed on the base and provided in form of a magnetorheological fluid (MRF) damper including a magnetic field generating portion, a magnetically permeable external roller, and a shaft, with the shaft coupled to the magnetic field generating portion and received in the magnetically permeable external roller, wherein two ends of the shaft stick out of the magnetically permeable external roller, and one of the two ends connects to a spindle of a motor, wherein the magnetically permeable external roller rotates relative to the shaft and the magnetic field generating portion, wherein a magnetorheological fluid (MRF) is filled between the magnetically permeable external roller and the magnetic field generating portion, wherein the magnetic field generating portion generates a magnetic field under which the MRF generates an anti-shear stress between the magnetically permeable external roller and the magnetic field generating portion rotating relative to the magnetically permeable external roller; a gear train disposed on the base and including a chain, a large gear, and a small gear, with the small gear coupled to the magnetically permeable external roller, wherein the chain connects the large gear and the small gear; a plurality of pulleys disposed on the support frame; a cable assembly disposed on the base and including a reel and a cable, with the reel coupled to the large gear, wherein a portion of the cable winds around the reel and another portion of the cable straddles the pulleys; a pulldown bar disposed at an end of the cable and hanging above the seat portion; and a controller electrically connected to the MRF resistance provider and the motor, wherein the controller controls a strength of a magnetic field generated from the magnetic field generating portion and controllably drives the motor, so as to control a weight provided by the MRF resistance provider and the motor to pull the cable downward.