Features of all pneumatic grips
- The separation of tensile and gripping forces ensures a constant gripping force over the course of the entire test sequence. For specimens prone to shrinkage, the gripping force is uniformly maintained by constant pneumatic pressure.
- The contact force on the specimen is reproducible.
- Gripping-sensitive specimens can be held securely by adjusting the pneumatic pressure, avoiding jaw breaks.
- The primary stress is the tensile load and it can be static or pulsating. Depending on the type of grips, compression and alternating load tests may be performed.
- Depending on the design principle, the gripping area is freely accessible.
- The larger grips can remain in place while small load cells, specimen grips, test fixtures and test devices are attached without having to dismantle the specimen gripsโa great time saver.
- There are a wide range of jaws with respect to material, surface, and area of the clamping surface.
- Pneumatic grips offer a low-cost alternative to hydraulic grips.
Differentiation into three types
There are three types of ZwickRoell pneumatic grips:
- Single-actuator
Single-actuator pneumatic grips can be used for the symmetrical and asymmetrical gripping of specimens (e.g., for shear strength tests). Some of the single-actuator pneumatic grips up to 1 kN have an integral control valveโno additional external pneumatic control unit required. - Double-actuator
Double-actuator pneumatic grips always close symmetrically with respect to the tensile axis. This eliminates the need for thickness adjustment: This is a big advantage, above all, for soft specimens and/or if specimen thickness changes. - For temperature chambers (single- and double-actuator)
These pneumatic grip are single- or double-actuator specimen grips that are specifically designed for use in temperature chambers.