Heavy Duty Circular Hydraulic Wedge Grips-TJ135

The series of hydraulic testing systems have been developed to meet the challenging demands of a varied range of both static and dynamic testing requirements. It provides complete testing solutions to satisfy the needs of advanced materials and component testing, and is ideally suited for fatigue testing and fracture mechanics. The compact design of the frame makes it ideal for installation within any laboratory environment, generally without the need for strengthened floors or raised ceiling heights.

Hydraulic wedge grips are suitable for static tensile and compression tests, as well as for fatigue tests under pulsating and alternating loading.

  • Connection is to the existing pressurized oil supply when used with. For use with static materials testing machines a small hydraulic power pack is required.
  • Extremely convenient operation – open-sided design allows easy specimen changing.
  • Interchangeable jaws are available to suit varying specimen (round and flat) dimensions.
  • Adjustable gripping pressure allows ‘soft’ specimens such as wood and plastics to be tested also.
  • Radial jaw-guide prevents undue axial stresses in the specimen. Also optionally available for superimposed torsion loading.

Principle of Operation:

Each grip functions independently of the other, an external hydraulic supply providing pressure to both open and close the grips.

When gripping pressure is applied, the relative vertical position of the specimen/jaw faces remains unchanged to prevent specimen load generation during the gripping process.

Once the grip faces contact the specimen the hydraulic pressure produces a vertical force on the grip head. The grip force will remain constant as the design automatically compensates for specimen thickness changes.


The 250kN hydraulic wedge action grips hold a test specimen between a stationary load frame member and a force producing actuator or crosshead.

You can use the grips for either static or dynamic materials testing applications. Interchangeable wedge-shaped grip jaw faces are available to accommodate either flat or round specimens.

As long as there is hydraulic pressure to the grips, the grips maintain a constant gripping force on a specimen regardless of the test forces acting on the specimen.



  • Excellent Repeatability _These grips clamp onto your specimen in the same position, test after test, to minimize the bending strains that can invalidate your test results.
  • Tension & Fatigue Capability: You can use the 647’s for both tensile and fatigue tests.
  • Adjustable Pressure: Hydraulic pressure can be adjusted, allowing these grips to be used for testing a variety of materials.
  • Multiple Wedge Selection: A wide variety of wedges are available to meet your requirements.
  • Easy Specimen Insertion: Side loading lets you quickly and easily insert specimens.
  • Free of backlash through zero loading due to hydraulic operated wedges, with a parallel gripping force application on the specimen.
  • Appropriate for torsion tests combined with axial load (optional).
  • Small design for a user friendly handling and combined use with optical extensometers.
  • Easy installation on the material testing machine by means of a mounting flange and adapters.• Installation possibility in static and dynamic material testing machines due to fitted connection systems and hydraulic power packs.
  • Scaling possibility through interchangeable inserts for flat and round specimens with various dimensions.