Quinton TM55, Service Manual

Page: 44 / 82

4-20 Repair/Replacement and Calibration Cardiac Stress Treadmills Service Manual
Adjusting the Grade Limit Switches
Grade limit switches prevent the treadmill from exceeding the preset
maximum grade. When a roller on the limit switch reaches a trigger in
each rack gear, a lever moves inward, opening the switch and stopping the
grade motor. Two grade limit switches, one on each side of the treadmill,
are mounted on brackets attached to the front of the headframe.
♦
Grade limit switch settings are preset at the factory and normally do not
require adjustment. They should be adjusted if the rack gear is changed.
1. Remove the treadmill hood and power as described in “Removing the
Treadmill Hood” on page 4-3.
2. Loosen, but do not remove, the two Phillips screws that secure each
grade limit switch to its bracket.
3. Pivot the switch on the upper screw towards, then away from, the
rack gear. You should hear a click as the switch opens or closes.
4. Set the switch wheel on a flat part of the rack gear. Pivot the switch
towards the rack gear just until it clicks, then tighten both screws.
5. If required, repeat steps 2-4 for the other grade limit switch.
6. If no other service is required, replace the treadmill hood as described
in step 9 on page 4-3.
7. Restore power and turn on circuit.
8. Operate the treadmill to verify that it reaches the upper and lower
grade limits (25% and 0%).