Linear actuation drive mechanism for power-assisted chairs

摘要

The chair of the present disclosure includes a power-assisted linear actuation drive mechanism having a lead screw nut which is linearly movable upon rotation of a power screw for selectively actuating the lift and tilt linkage mechanism for causing forward lifting and tilting movement of the chair when the motor is operated in a first direction. Rotation of the screw shaft in a second opposite direction acts to lower the chair to the normal seating position. Continued rotation in the second direction causes a first cam block pivotably mounted to the lead screw nut to engage a first follower assembly for causing extension of the leg rest assembly. Further rotation in the second direction causes a second cam block pivotably mounted to the lead screw nut to engage a second follower assembly for causing reclining movement of the chair. This sequential operation of the leg rest assembly and the reclining linkage are independent and may be easily disabled to selectively eliminate either of the features.