Patent ID: 11883334
Assignee: STRYKER CORPORATION
Field: Medical technology (Instruments)
Classification: CPC A | IPC A

Claim 8:
9. A patient transport apparatus comprising:
a support structure arranged for movement along a floor surface;
a support wheel coupled to the support structure, with the support wheel being swivelable about a swivel axis; and
an auxiliary wheel system including:
a support frame coupled to the support structure;
an auxiliary wheel assembly coupled to the support frame and positionable between a deployed position engaging the floor surface and a stowed position spaced from the floor surface, the auxiliary wheel assembly including:
an auxiliary wheel configured to influence motion of the patient transport apparatus over a floor surface,

a motor assembly coupled to the auxiliary wheel and having a motor assembly housing and a motor positioned within the motor assembly housing and coupled to the auxiliary wheel for providing motive power to the auxiliary wheel,
a crank shaft rotatably coupled to the support frame, and
a wheel support frame extending radially outwardly from the crank shaft and coupled to the auxiliary wheel such that a rotation of the crank shaft causes a vertical movement of the auxiliary wheel; and

an actuator assembly coupled to the support frame and to the auxiliary wheel assembly, the actuator assembly including:
a spring cartridge assembly configured rotate the crank shaft to bias the auxiliary wheel towards the deployed position; and
a lift actuator operable to move the spring cartridge assembly to rotate the crank shaft and wheel support frame to move the auxiliary wheel to the deployed position and to the stowed position.