A positioning mechanism of a bed is disclosed. In one such embodiment, a bed can comprise an undercarriage frame, a patient surface frame, a plurality of lifters, and at least one load cell in communication with the patient surface frame. Such a load cell can be adapted to communicate a signal associated with a force exerted from the patient surface frame. The force exerted from the patient surface frame is perpendicular to the load cell when the patient surface frame is oblique to the undercarriage frame.
