Linear actuation drive mechanism for power-assisted chairs

摘要

A chair including a power-assisted linear actuation drive mechanism having a cam guide which is linearly movable upon rotation of a shaft for selectively actuating a lift and tilt linkage mechanism, and for causing forward lifting and tilting movement of the chair when a motor of the mechanism is operated in a first direction. Rotation of a shaft in a second opposite direction acts to lower the chair to a normal seating position. Continued rotation in the second direction causes a first cam block pivotably mounted to the cam guide to engage a first follower assembly for causing extension of a leg rest assembly and for causing a rearward tilt of the chair frame. Further rotation in the second direction causes a second cam block pivotably mounted to the cam guide to engage a second follower assembly for causing reclining movement of the chair and for causing an additional rearward tilt of the chair frame. 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.