Patent ID: 7007765

Claim:
A method for driving a wheeled carriage used for supporting and transporting a person in a substantially horizontal position, the carriage including a patient support having a length, opposing ends of the length comprising a head end and a foot end of said patient support, a wheeled base having a length and supporting said patient support and enabling movement of said patient support, an auxiliary wheel mechanism secured to said wheeled base and for positioning at least one auxiliary wheel into a first position contacting a floor below the wheeled carriage and into a second raised position out of engagement with the floor, a drive motor assembly including a drive motor for driving said auxiliary wheel, the method comprising the steps of, when said carriage is in a rest position and the auxiliary wheel contacts the floor: (a) sensing a drive signal input by an operator for driving said at least one auxiliary wheel in a first direction; (b) calculating a power signal based on the drive signal and a time value measured during a predetermined time period following start of the drive signal; (c) applying the power signal to the drive motor to drive the auxiliary wheel; and (d) repeating steps (a)–(d) until the time value measured equals the predetermined time period, the step of calculating the power signal then being based only on the drive signal.