PNEUMATIC WEDGE ACTION GRIPS

Pneumatic wedge action grips feature an open front design, which facilitates easy loading of large specimens. This series can accommodate round specimens up to 60 mm (2.36 in) in diameter and flat specimens up to 70 mm (2.75 in) thick. The compact design of these pneumatic wedge grips provides optimum use of the test area when installed on a Instron® floor model testing systems. Specially suited for industrial environments where dust and metal chips may be present, these grips have protective dust covers that fit easily over the faces to shield the moving surfaces. An optional piggyback adapter plate furnishes an efficient method for mounting secondary load strings for lower capacity testing without removing the larger grips. On the 2716-11x and 2716-12x grips, the vee-faces used for round specimens are designed with a reduced area at the center, which compromises their ability to absorb high energy breaks without fracture. This grip uses a split vee-face configuration which allows the break energy to be dissipated without damaging the faces. On the W-5180 and W-5160 grips, the considerable increase in size allows the use of a one-piece design grip face.

Principle of Operation

These grips are operated with a control knob mounted on the grip or with an Instron standard pneumatic control kit. Powered by pneumatic control, the faces are moved by a pneumatic piston, which eliminates a costly hydraulic pump and its control. When under load, the wedge action provides additional clamping pressure to minimize specimen slippage. The 2716-11x and 2716-12x grips use a unique carrier/ face mounting system that allows for easy face insert changes. The carrier is placed on the grips and secured by springs from the grip body and against the driving piston. The faces sit on the carriers, held by a couple of thumb screws. The lubrication of the jaw face carriers is through a standard grease fitting, eliminating the need to remove either the faces or the carriers for greasing. Each face set can accommodate a wide range of specimen types, offering flexibility with a minimum number of face changes. W-5180 and W-5160 grips include a face mounting system with embedded magnets and jaw faces with circular centering disks. This design simplifies jaw face loading and holds the jaws in position when no load is applied.

Application Range

• Type of loading: Tension — not suitable for throughzero/ reverse stress or fatigue testing

• Specimen material: Wires, plastics, metals

• Specimen shapes: Flat, round

Safety Advice

Review safety note on page 234