MTS Series 685 Hydraulic Grip Supply - Manual (Page 38)

Series 685 Grip Supply Product Information 38
How to Remove a Specimen from Grips
Operation
Because of the large variety of load frame, grip, and controller equipment in
use, it is impossible to give explicit instructions for this process.
Pliers or tong-like tools, such as those used for installing or removing
cartridge-type electrical fuses, are often used for holding small specimens in
proper position within the grips to lessen the possibility of having fingers
pinched or crushed during the gripping process.
Gripping a specimen typically involves manually placing the specimen
within the upper grip and then, with the specimen correctly in place,
applying hydraulic gripping pressure to the upper grip. Then, the actuator
must be positioned to grip the lower portion of the specimen before
hydraulic gripping pressure is applied.
A. Perform any operations necessary to correctly position one end of the
specimen within the upper grip.
B. When the specimen is properly positioned within the upper grip, rotate
the upper grip control clockwise to the grip position.
C. Perform any operations necessary to correctly position one end of the
specimen within the lower grip.
D. When the specimen is properly positioned within the lower grip, rotate
the lower grip control clockwise to the grip position.
Note While applying test loads to specimens mounted in the grips, leave the
grip controls in the grip position and leave the hydraulic grip supply
turned on.
How to Remove a Specimen from Grips
To remove a specimen from the grips:
Do not put anything in a crush zone when turning on hydraulic power.
Heavy specimens or specimen fragments falling from the grips can injure
you or damage test equipment.
Take adequate precautions to support heavy specimens while releasing them
from the grips.
1. If needed, provide adequate support for the specimen, and turn the upper
grip control to the release position.
2. If the specimen is broken, remove the upper portion.
3. Determine whether it is necessary to reposition the crosshead or actuator to
provide adequate clearance for removal of the lower part of the specimen.
Reposition the crosshead or actuator, as needed.
4. If needed, provide adequate support for the specimen, and rotate the lower
grip control to the release position.
WARNING