Fifth wheel assembly for bed

A wheeled carriage for supporting a patient in a substantially horizontal position, comprising:

• a patient support having a length, opposing ends of the length comprising a:
• head end and a foot end of said patient support, said patient support having a pair of lateral sides intermediate the head and foot ends;
• a wheeled base having a length and supporting said patient support and enabling movement of said patient support, said wheeled base including at least four floor surface engaging and castered wheels spaced from one another;
• an auxiliary wheel assembly secured to said wheeled base and including a rotatable support shaft with an axis and a stop element mounted to said rotatable support shaft, said auxiliary wheel assembly further including:
• an auxiliary wheel support bracket having a first end rotatably secured to said support shaft to enable rotation about the axis of said support shaft, said auxiliary wheel support bracket having a stop thereon;
• an auxiliary wheel support spring for continually urging said auxiliary wheel support bracket in a first direction about the axis of said support shaft and said stop into engagement with said stop element;
• at least one auxiliary wheel rotatably secured to a second end of said auxiliary wheel support bracket;
• a shaft spring secured at an end of said rotatable support shaft for continually urging said rotatable support shaft to a position whereat said auxiliary wheel is spaced from a floor surface;
• and
• a deployment apparatus for rotating said rotatable support shaft and said stop element in said first direction about its axis against said shaft spring to move said auxiliary wheel between a stowed position spaced from the floor surface and a deployed position engaging the floor surface;
• whereby in the deployed position, when said auxiliary wheel contacts the floor surface, said auxiliary wheel and said auxiliary wheel support bracket pivot about the axis of said support shaft so that said stop and stop element separate and each of said castered wheels and said at least one auxiliary wheel maintain contact with the floor surface.