Variable speed patient transfer apparatus

1. A patient transfer apparatus comprising:

a frame;

a track assembly including a track coupled to the frame and movable relative to the frame for traversing stairs in an ascending direction and in a descending direction opposite the ascending direction;

a brake configured to selectively apply a braking force imparted on the track based on movement of the track in the ascending direction or descending direction, wherein the brake includes a motor operably coupled to the track to drive the track to apply the braking force;

an operator interface operatively attached to the frame and arranged for user engagement, the operator interface including:

a direction selector operable by the user to select between forward movement of the track for ascending stairs and backward movement of the track for descending stairs, and

a speed selector operable by the user to select between a plurality of speed settings for the motor including a slow speed, a fast speed, and one or more intermediate speeds between the slow speed and the fast speed; and

a controller coupled to the motor and to the operator interface configured to operate the motor by adjusting an output of the motor in a selected direction and at a selected one of the plurality of speed settings based on user engagement with the operator interface, the controller being configured to operate the motor:

in a first direction to drive the track with movement for descending stairs in response to user engagement with the operator interface,

in a second direction, opposite to the first direction, to drive the track with movement for ascending stairs in response to user engagement with the operator interface,

in the second direction to impart the braking force on the track to stop the patient transfer apparatus from moving in the descending direction along stairs in response to an absence of user engagement with the operator interface, and

when the patient transfer apparatus is traversing the stairs and when slip is occurring between the track and the stairs, to decrease or halt the slip.

2. The patient transfer apparatus of claim 1 , wherein the brake is configured to apply the braking force upon movement of the track in the descending direction.

3. The patient transfer apparatus of claim 1 , wherein the brake is configured to not apply the braking force upon movement of the track in the ascending direction.

4. The patient transfer apparatus of claim 1 , wherein the track assembly further includes an axle and a pulley being concentric with the axle and configured to support the track.

5. The patient transfer apparatus of claim 1 , further comprising a seat, wherein the controller is configured to adjust the output of the motor based on a weight or load on the seat.

6. The patient transfer apparatus of claim 1 , wherein the controller is configured to adjust the output of the motor to a target output that is based on a difference between a target speed of the patient transfer apparatus and an actual speed of the patient transfer apparatus.

7. The patient transfer apparatus of claim 1 , wherein the target speed of the patient transfer apparatus is:

a first speed during operation of the speed selector in the slow speed setting,

a second speed setting during operation of the speed selector in one of the intermediate speed settings, and

a third speed setting during operation of the speed selector in the fast speed setting.

8. The patient transfer apparatus of claim 1 , wherein the frame includes:

a pair of rear vertical members, and

a U-shaped top handle supported for translating movement relative to the pair of rear vertical members.

9. The patient transfer apparatus of claim 8 , wherein the operator interface is operatively attached to the U-shaped top handle and is spaced laterally between the pair of rear vertical members.

10. The patient transfer apparatus of claim 9 , wherein the frame includes a rear horizontal member extending laterally between the pair of rear vertical members; and

wherein the U-shaped top handle is spaced vertically above the rear horizontal member.

11. The patient transfer apparatus of claim 10 , further comprising a pair of rear handles each operatively attached to a respective one of the pair of rear vertical members and spaced vertically below the rear horizontal member.

12. The patient transfer apparatus of claim 1 , wherein the controller is further operable to determine occurrence of the slip based upon:

monitoring a current to the motor;

comparing the current to the motor to a current threshold; and

determining occurrence of the slip based upon the current to the motor being below the current threshold.

13. The patient transfer apparatus of claim 1 , wherein the controller is further operable to determine occurrence of the slip based upon:

monitoring a speed of the apparatus;

monitoring a speed of the track;

comparing the speed of the apparatus to the speed of the track; and

determining occurrence of the slip based a difference of the speed of the apparatus and a speed of the track exceeding a threshold.

14. The patient transfer apparatus of claim 1 , wherein the controller being configured to operate the motor to decrease or halt the slip includes controlling the motor to a predetermined slipping speed.

15. The patient transfer apparatus of claim 1 , wherein the controller being configured to operate the motor to decrease or halt the slip includes controlling the motor to stop.