Non-adjustable linear drive for articulated furniture

A linear drive for an articulated furniture piece such as articulated chairs and beds, comprising:

• a housing, a rotary motor in the housing having an output shaft, gearing in the housing connected to be driven by the output shaft, a rotary screw projecting from the housing and driven by the gearing, a linearly reciprocable drive member connected to be driven by the rotary screw, control means for the motor including means for causing rotation of the motor in opposite directions and means for limiting rotation of the motor in both directions to a predetermined number of revolutions so the linearly reciprocable drive member has a predetermined retracted position and a predetermined extended position, and means for preventing inadvertent reorientation in the retracted and extended positions of the linearly reciprocable drive member from present positions including means to rotationally lock the drive member with respect to the housing in all positions of the drive member, said control means for limiting rotation of the motor in both directions including rotary cam means and limit switch means, said rotary cam means being driven by the motor and said limit switch means being positioned to be engaged by the rotary cam means, said linearly reciprocable drive member including a drive nut engaging the rotary screw and a round drive tube fixed thereto, a stationary guide sleeve fixed to the housing that slidably receives the round tube, said means for preventing inadvertent reorientation in the retracted and extended positions of the linearly reciprocable drive member including a slot in one of the round tube and guide sleeve and a projection on the other extending into the slot to prevent rotation between the round tube and the guide sleeve.

An articulated chair or bed, comprising:

• a frame, an articulated member movably mounted on the frame, a linear drive mounted on the frame for moving the articulated member relative to the frame including a housing, a rotary motor in the housing having an output shaft, gearing in the housing connected to be driven by the output shaft, a rotary screw projecting from the housing and driven by the gearing, a linearly reciprocable drive member connected to be driven by the rotary screw, control means for the motor including means for causing rotation of the motor in opposite directions and means for limiting rotation of the motor in both directions to a predetermined number of revolutions so the linearly reciprocable drive member has a predetermined retracted position and a predetermined extended position, and means for preventing inadvertent reorientation in the retracted and extended positions of the linearly reciprocable drive member from present positions including means to rotationally lock the drive member with respect to the housing in all positions of the drive member, including control means for limiting rotation of the motor in both directions including rotary cam means and limit switch means, said rotary cam means being driven by the motor and said limit switch means being positioned to be engaged by the rotary cam means, said linearly reciprocable drive member including a drive nut engaging the drive screw and a round drive tube fixed thereto, a stationary guide sleeve fixed to the housing that slidably receives the round tube, said means for preventing inadvertent reorientation in the retracted and extended positions of the linearly reciprocable drive member including a slot in one of the round tube and guide sleeve and a projection on the other extending into the slot to prevent rotation between the round tube and the guide sleeve.