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Pneumatic Grips

Pneumatic grips are particularly useful when a variety of materials, especially those sensitive to clamping forces, must be gripped with minimum amount of changeover. The gripping force is generated by pneumatic actuators acting on the jaws directly or via a lever system.

Pneumatic Grips

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 grips—a 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 valve—no 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.