Patient transport apparatus with controllable auxiliary wheel assembly
First Claim
1. A patient transport apparatus for transporting a patient over a surface, said patient transport apparatus comprising:
- a base;
support wheels coupled to said base and swivelable about swivel axes;
an auxiliary wheel assembly coupled to said base and comprising an auxiliary wheel configured to move between a stowed position spaced from the surface and deployed positions in contact with the surface, said auxiliary wheel assembly further comprising an actuator operably coupled to said auxiliary wheel to move said auxiliary wheel between said stowed position and said deployed positions;
a sensing system; and
a controller coupled to said sensing system to acquire a measurement associated with a current load applied to said auxiliary wheel, said controller configured to generate a control signal based on comparing said measurement to a predetermined value associated with a desired load, and to apply said control signal to said actuator thereby adjusting said current load relative to said desired load; and
wherein said controller is configured to acquire measurements associated with current loads applied to said auxiliary wheel over time and to generate said control signal based on minimizing deviation between said measurements and said predetermined value.
1 Assignment
0 Petitions
Accused Products
Abstract
A patient transport apparatus transports a patient over a surface. The patient transport apparatus comprises a base and support wheels coupled to the base. An auxiliary wheel assembly is coupled to the base to influence motion of the patient transport apparatus over the surface to assist caregivers. The auxiliary wheel assembly comprises auxiliary wheels and an actuator operably coupled to the auxiliary wheels. A controller adjusts the actuator based on input from a sensing system so that frictional forces acting between the auxiliary wheels and the surface are sufficient for steering and maneuvering of the patient transport apparatus, without sacrificing stability of the patient transport apparatus.
53 Citations
19 Claims
-
1. A patient transport apparatus for transporting a patient over a surface, said patient transport apparatus comprising:
-
a base; support wheels coupled to said base and swivelable about swivel axes; an auxiliary wheel assembly coupled to said base and comprising an auxiliary wheel configured to move between a stowed position spaced from the surface and deployed positions in contact with the surface, said auxiliary wheel assembly further comprising an actuator operably coupled to said auxiliary wheel to move said auxiliary wheel between said stowed position and said deployed positions; a sensing system; and a controller coupled to said sensing system to acquire a measurement associated with a current load applied to said auxiliary wheel, said controller configured to generate a control signal based on comparing said measurement to a predetermined value associated with a desired load, and to apply said control signal to said actuator thereby adjusting said current load relative to said desired load; and wherein said controller is configured to acquire measurements associated with current loads applied to said auxiliary wheel over time and to generate said control signal based on minimizing deviation between said measurements and said predetermined value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
-
-
19. A patient transport apparatus for transporting a patient over a surface, said patient transport apparatus comprising:
-
a base; support wheels coupled to said base and swivelable about swivel axes; an auxiliary wheel assembly coupled to said base and comprising an auxiliary wheel configured to move between a stowed position spaced from the surface and deployed positions in contact with the surface, said auxiliary wheel assembly further comprising an actuator operably coupled to said auxiliary wheel to move said auxiliary wheel between said stowed position and said deployed positions; a sensing system, said sensing system comprising a speed sensor to measure a rotational speed of said auxiliary wheel, and a second speed sensor to measure a rotational speed of one of said support wheels; and a controller coupled to said sensing system to acquire a measurement associated with a current load applied to said auxiliary wheel, said controller configured to generate a control signal based on comparing said measurement to a predetermined value associated with a desired load, and to apply said control signal to said actuator thereby adjusting said current load relative to said desired load; and wherein said controller is configured to compare said rotational speed of said auxiliary wheel to said rotational speed of said one of said support wheels to determine if said auxiliary wheel is slipping on the surface.
-
Specification