Stryker Corporation
Patient support apparatus with actuator feedback

Abstract:

A patient support apparatus--such as a bed, chair, cot, stretcher, or the like--includes a frame, support surface, movable component, an actuator, and a controller. The actuator includes a motor, an encoder, a spindle, an extendable arm, multiple power switches, and a position switch. The controller estimates a position of the extendable arm based on motor encoder signals and updates the position estimate when the arm triggers the position switch. The power switches cut power to the motor without intervention by the controller when the extendable arm triggers either of the power switches. In some embodiments, the motor is a brushless DC motor. In still other embodiments, multiple position switches are adapted to be open in different ranges of position, and the controller determines which range the extendable arm is located in based on the state of the position switches.