Abstract: A bed frame comprises a lower support structure having a head end and a foot end and a carriage arranged for translational movement on the lower support structure. An upper support structure is mounted on the carriage. The upper support structure includes a seat and an upper body support section pivotally connected thereto. A support arm is pivotally connected between the lower support structure and the upper body support section. An actuator is connected to the lower support structure. A lever arm is connected between the actuator and the carriage. Application of force from the actuator to the lever arm moves the carriage on the lower support structure. The support arm is arranged such that movement of the carriage toward the head end of the lower support structure produces a lifting moment on the upper body support section.