Method for driving a wheeled carriage

• US 7,007,765 B2
• Filed: 04/28/2004
• Issued: 03/07/2006
• Est. Priority Date: 01/21/2000
• Status: Expired due to Term

• Current Assignee: Stryker Corporation
• Original Assignee: Stryker Corporation
• Inventors: Mulder, Craig, Reed, Dennis, Waters, Keith, Friedman, Mark, Nichols, Steve
• Primary Examiner(s): Morris, Lesley D.
• Assistant Examiner(s): Luby, Matthew
• Application Number:
  US10/833,552
• Publication Number:
  US 20040200646A1
• Time in Patent Office: 678 Days
• Field of Search: 180 651- 656, 180/15, 180/16, 180/19.1, 180/19.3, 560/0
• US Class Current: 180/19.3
• CPC Class Codes: A61G 1/0225 other configuration, e.g. odd number of wheels
• CPC Class Codes: A61G 1/0237 having at least one swivelling wheel, e.g. castors
• CPC Class Codes: A61G 1/0268 having deployable or retractable wheels
• CPC Class Codes: A61G 1/0287 having brakes, e.g. slowing down and/or holding details of brake actuators on castors B60B33/0078; brakes on hand carts B62B5/04; brakes in general F16D49/00 - F16D65/853
• CPC Class Codes: A61G 7/08 Apparatus for transporting beds
• CPC Class Codes: B60L 2200/24 Personal mobility vehicles
• CPC Class Codes: B60L 2250/16 by display
• CPC Class Codes: B60L 2270/145 Structure borne vibrations
• CPC Class Codes: B60L 3/00 Electric devices on electrically-propelled vehicles for safety purposes; Monitoring operating variables, e.g. speed, deceleration or energy consumption methods or circuit arrangements for monitoring or controlling batteries or fuel cells B60L58/00
• CPC Class Codes: B60L 3/0092 with use of redundant elements for safety purposes
• CPC Class Codes: B60L 50/20 using propulsion power generated by humans or animals
• CPC Class Codes: B60L 58/12 responding to state of charge [SoC]
• CPC Class Codes: B60L 7/24 with additional mechanical or electromagnetic braking
• CPC Class Codes: B62D 51/04 the driver walking
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

A powered wheeled carriage includes a patient support and a wheeled base. An auxiliary wheel mechanism includes an auxiliary wheel spring support for biasing an auxiliary wheel into contact with a floor. Operating a control apparatus moves the auxiliary wheel away from the floor. A drive handle pivots about a single axis to control a drive motor that powers the auxiliary wheel. The drive handle controls driving of the wheeled carriage in forward and rearward directions. A decision/drive circuit ramps the speed of the wheeled carriage for a few second after start-up to prevent a jerking motion. A display/control panel displays the condition of the carriage brake and the condition of the auxiliary wheel to assist an operator.

Claims

1. 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.

2. The method for driving a wheeled carriage of claim 1, wherein as the measured time value increases, the power signal based on the drive signal increases, even when a drive value of the drive signal remains constant, to provide a ramping effect for the velocity of the carriage during the predetermined time period.

3. The method for driving a wheeled carriage of claim 1, wherein the step of calculating a power signal comprises multiplying the drive signal by a ramp multiplier, the ramp multiplier increasing as a function of the measured time value during the predetermined time period after start of the drive signal to provide a ramping effect on the velocity of the carriage during the predetermined time period.

4. The method for driving a wheeled carriage of claim 3, wherein the ramp multiplier becomes a constant value when the time value equals the predetermined time period.

5. The method for driving a power assisted wheeled carriage of claim 1, wherein the drive motor comprises a DC electric motor, and the step of applying the power signal comprises providing pulse width modulation signals to the DC electric motor.

6. The method for driving a power assisted wheeled carriage of claim 1, wherein the drive signal has a first range of values for driving the auxiliary wheel in a first direction and a second range of values for driving the auxiliary wheel in a second opposing direction.

7. A method for driving a power assisted 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, castered wheels mounted at each opposing corner at each opposing end of said wheeled base, 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 in one of a first direction and a second opposing direction, said auxiliary wheel being located at a position toward a central section inwardly with respect to said castered wheels of said carriage, and a battery for supplying power to said drive motor, the method comprising the steps of, when said carriage is in a rest position:

sensing that a power cable is not connected to an external AC power supply;

sensing that a brake of the wheeled carriage is in a released position;

sensing that the charge of the battery exceeds a minimum charge value;

sensing that the auxiliary wheel is in engagement with the floor;

the method further comprising when

     1) the power cable is not connected to the external AC power supply,

     2) the brake is in the released position,

     3) the charge of the battery exceeds the minimum charge value, and

     4) the auxiliary wheel is in engagement with the floor, the steps of;

(a) sensing a drive signal for driving said at least one auxiliary wheel in a first direction;

(b) calculating a power signal based on 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 drive signal is no longer sensed.

8. The method for driving a power assisted wheeled carriage of claim 7, wherein the step of calculating a power signal comprises calculating the power signal based on the drive signal and a time value since start of the drive signal so that the step of calculating the power signal is not based only on the drive signal until after the time value equals a predetermined time period.

9. The method for driving a power assisted wheeled carriage of claim 8, wherein as the time value increases, the power signal based on the drive signal increases even while a drive value of the drive signal remains constant to provide a ramping effect for the velocity of the carriage during the predetermined time period.

10. The method for driving a power assisted wheeled carriage of claim 8, wherein the step of calculating a power signal comprises multiplying the power signal based on the drive signal by a ramp multiplier, the ramp multiplier increasing as the time value increases after start of the drive signal to provide a ramping effect on the velocity of the carriage during the predetermined time period.

11. The method for driving a power assisted wheeled carriage of claim 10, wherein the ramp multiplier becomes a constant value when the time value equals the predetermined time period.

12. The method for driving a power assisted wheeled carriage of claim 7, wherein the drive motor comprises a DC electric motor, and the step of applying the power signal comprises providing pulse width modulation signals to the DC electric motor.

13. The method for driving a power assisted wheeled carriage of claim 7, wherein the drive signal has a first range of values for driving the auxiliary wheel in the first direction and a second range of values for driving the auxiliary wheel in the second opposing direction.

14. A method for driving a power assisted 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, castered wheels mounted at each opposing corner at each opposing end of said wheeled base, 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 in one of a first direction and a second opposing direction, said auxiliary wheel being located at a position toward a central section inwardly with respect to said castered wheels of said carriage, and a battery for supplying power to said drive motor, the method comprising the steps of, when said carriage is in a rest position and an on/off switch enables driving of said auxiliary wheel:

sensing that a brake of the wheeled carriage is in a released position;

sensing that the auxiliary wheel is in engagement with the floor;

the method further comprising when

     1) the brake is in the released position, and

     2) the auxiliary wheel is in engagement with the floor,

the step of sensing a drive signal from a drive member controlled by an operator for driving said at least one auxiliary wheel and providing a power signal to said drive member to drive said auxiliary wheel in one of the first direction and the second opposing direction.

15. The method for driving a power assisted wheeled carriage of claim 14, wherein an operator controls the drive member so that the drive signal has a first range of values for driving the auxiliary wheel in the first direction and a second range of values for driving the auxiliary wheel in the second opposing direction.

16. The method for driving a power assisted wheeled carriage of claim 14, including the step of sensing that a power cable is not connected to an external AC power supply to enable the step of sensing a drive signal to drive said auxiliary wheel.

17. The method for driving a power assisted wheeled carriage of claim 14, including the step of sensing that the charge of the battery exceeds a minimum charge value to enable the step of sensing a drive signal to drive said auxiliary wheel.