A transfer chair has a chair frame, a seat, wheels, and a lift arm which has an articulated path between home and target positions. The articulated path may define a limited clearance height to allow use with, e.g., cars having a small door opening. In one embodiment the seat is split and moves to allow passage of the lift arm as it travels along the articulated path. The lift arm is articulated such that a lifting bridle attached to a distal end of the lift arm is maintained in a constant
angular orientation with respect to the chair frame during movement. The lift arm further has multiple deployment paths for target positions with different heights and distances. A transfer seat for the lift arm includes two flexible webs removably attached to the lifting bridle. The lift arm is constructed using four links which are pivotally connected end-to-end. The links can be folded to a stowed position within the chair frame. An actuation mechanism uses a lead-screw
actuator coupled to one of the links which lifts the remaining links by rotation about its pivotal attachment to the chair frame, and similarly uses another lead-screw
actuator coupled to the next link. The actuation mechanism can be operated by an on-board
motion control computer for controlling the trajectory and velocity of the arm. Sensors provide trajectory information to the on-board computer, and a docking switch can select one of a plurality of target trajectories for deploying the lift arm. A
docking station integrated with the frame mates with a docking feature on the target object and stabilizes the chair while transferring the user. The
docking station may include a receptacle for
electrical connection to a power supply. A more comprehensive
transfer system is provided using a path sensor which tracks a sensible path
proximate the target object, and an
electronic controller responsive to the path sensor which operates the drive wheels to follow the sensible path to a
stowage location. The transfer chair drive wheels may be caregiver-operated using
throttle handlebars.