Electrically Operated General Ward Bed
Page 3 - 1
Operation and Maintenance Manual
(154588 REV 1)
3
Chapter 3
Theory of Operation
Electrical System
HI/LO
A dual actuator system operates the HI/LO function. The actuators extend at
the same time to raise the bed. The actuators retract at the same time to lower
the bed.
Backrest
A single actuator extends to raise and retracts to lower the backrest. This
actuator is also fitted with a cable-operated quick release system. The actuator
is free-wheeling. If an obstruction is present, the actuator will free-wheel to
avoid damage.
Knee-Break
A single actuator extends to raise and retracts to lower the knee-break. This
actuator is fitted with internal limit switches to stop the actuator at the fully
extended and fully retracted positions. The actuator is free-wheeling. If an
obstruction is present, the actuator will free-wheel to avoid damage.
Trendelenburg
The actuators used for the HI/LO function also operate the Trendelenburg
system.
When the bed is tilted, one actuator extends while the other retracts. These
actuators are fitted with internal limit switches. These internal limit switches
allow the bed to self-level at the lowest position and at the highest position.
The self-level function is designed so that the bed can be lowered while in
Trendelenburg or Reverse Trendelenburg positions without the risk of
interference between the bed parts.