Instron 300DX, Operating Instructions Manual

Page: 42 / 96

Chapter 3: Operation
42 M47-17027-EN
Operate grip assemblies - G1-style and G7-style
crossheads
Warning
Warning
Caution
Improper alignment of grip jaws and specimen will cause grip jaw damage and lead to grip
pocket deformation. Be sure to read and obey the guidelines outlined on page 43 through
page 44 .
Grip assemblies are provided on frames with either G1-style or G7-style crossheads. Both the tension
and adjustable crossheads are equipped with grip assemblies that are designed to grip specimens for
tensile testing. Frames can be purchased with either manual grip actuation (G1-style crossheads) or
hydraulic grip actuation (G7-style crossheads).
Regardless of which type of grip actuation your frame is equipped with, the basic method of grip operation
is the same. Each crosshead has a grip pocket with sloped sides (see
Figure 10 on page 48 and
Figure 11 on page 53 ). A matching pair of grip jaws fits into each grip pocket. The initial clamping force
on the specimen is applied manually or hydraulically (as per crosshead style - G1 or G7), and then as load
is applied to the specimen, the sloped sides of the grip pockets cause the grip jaws to tighten further on
the specimen.
The grip jaws are purchased separately from the frame so that the appropriate jaw type can be chosen for
your specific application. See
“Grip jaw selection” on page 43 for some tips on selecting the
appropriate grip jaws for your application.
Use of Molykote type GN metal paste (high pressure lubricant) is necessary for proper operation of the
grips. Instron recommends only this brand and type of high pressure lubricant. Use of any other
lubricant risks damage to the grip components. This damage would not be covered under warranty. A
small amount of Molykote type GN metal paste is supplied with the frame, additional quantities can be
purchased from Instron, contact your local Instron Services department as directed on page
20 . Be sure
to apply the lubricant as specified in these instructions.
The following sections provide more details on grip jaw selection, grip jaw installation, and grip use. Refer
to the appropriate section for your frame’s crosshead style.
Always wear appropriate personal protective equipment when preparing, operating and
maintaining this equipment. Personal protective equipment should include, but is not
limited to, eye protection and head protection. Other types of personal protective
equipment may also be needed. You must perform your own risk assessment and take
appropriate measures to protect yourself from harm.
These grips are designed to grip specimens for testing. Therefore, an unavoidable pinching
hazard exists. Make sure to read and understand all installation, removal and operating
instructions before using the grips!