Removing fixtures with spiral washers, Removing fixtures with spiral washers 34 – MTS Series 247 Actuators User Manual
Page 34
Series 247 Actuators
34
Spiral Washers
Installation
Removing Fixtures with Spiral Washers
The procedure requires two spanner wrenches and assumes you are familiar with
all operating aspects of your system.
Note
Sometimes you might have multiple fixtures in the force train that have
different force ratings. When removing the fixtures pretensioned with
spiral washers, remove the fixtures with the lowest force rating first. Then
remove any other fixtures from the lowest to the highest force rating.
1. Ensure that system hydraulic pressure has been reduced to zero before
proceeding. To do this, turn off the hydraulic power unit and exercise the
actuator until it stops moving.
2. Install a dummy specimen or a suitable fixture in the force train such that it
can withstand a tensile load 10 to 20% greater than the maximum load to be
applied during testing.
3. Select force control at the system controller.
4. Apply system hydraulic pressure according to applicable system procedures.
Do not exceed the maximum HPS output pressure or apply a force greater
than the capacity of any component in the force train.
Exceeding the tensile load capacity of any element in the force train can
cause equipment damage and/or personal injury.
It is necessary to temporarily exceed the tensile load capacity to achieve the
requirements of
in this procedure. This is accomplished by increasing the
output pressure of the HPS. Contact MTS Systems Corporation.
Note
Be sure all components in the force train can accommodate the required
tensile load.
5. Apply a static tensile load 10 to 20% higher than the maximum load to be
applied during testing.
6. Use the spanner wrenches to rotate the spiral washers to reduce their
combined thickness to a minimum.
7. Reduce tensile load to zero and remove hydraulic pressure. Ensure that all
residual pressure (including accumulator pressure) has bled off.
8. Remove all force train components (such as load cell, swivel rod end, grips,
or fixtures) attached to the actuator.