Wheeled carriage having auxiliary wheel spaced from center of gravity of wheeled base and cam apparatus controlling deployment of auxiliary wheel

摘要

A wheeled carriage for supporting a patient in a substantially horizontal position, the wheeled carriage has thereon a patient support having head and foot ends and a wheeled base supported by castered wheels. An auxiliary wheel and a wheel support structure therefor suspendedly mount the auxiliary wheel at its axis to the wheeled base at a distance L in a horizontal direction from the center of gravity of the wheeled carriage along the length of the wheeled base when the auxiliary wheel is engaged with the floor surface. A moment Mmass is defined by the distance L multiplied by a force Fmass, the force Fmass being defined by the mass of the carriage or carriage and patient at the center of gravity. The moment Mmass is greater at all times than a moment Mforce to prevent teetering of the wheeled carriage, where moment Mforce is defined by multiplying the height H by a force Fmax. The force Fmax is the force required to move the wheeled carriage. The height H is defined by the vertical distance between the axis of the auxiliary wheel and the relative height of the gripping location where the force Fmax is applied.