Mechanical - Wedge Grips

Instron mechanical wedge action grips may be used in static or dynamic materials testing applications, interchangeable wedge-shape grip faces accommodating either flat or round specimens.

The grip is designed to allow test specimens to be securely gripped without introducing axial pre-loading to the specimen. This is achieved by using jaw faces that move in a horizontal direction only, relative to the specimen.

Application Range

  • Type of loading: Static or dynamic, reverse stress. 
  • Specimen material: Metallics, plastics, composites. 
  • Specimen geometries: Round section (not buttonhead) or flat specimens with or without shoulder tab.

Principle Of Operation

Each grip is mechanically operated, gripping force being applied via movement of the grip body relative to the wedge shaped jaw faces. This movement is induced by the tightening of four socket cap screws on the underside of the grip head.

Each jaw face is located in the grip body by two extension springs, which allow the jaw faces to release the specimen after testing. 

The grip body wedge area is fitted with jaw guides, to ensure that the jaw faces remain square to each other and to the specimen.