Eccentric Roller Grip is a general-purpose grip for flat samples. These are self-tightening grips primarily designed for the precision testing of elastomeric and other flexible materials exhibiting a large reduction in cross-section area under load. The sample is held between the body and the eccentrically mounted roller as the load increases the gripping action becomes self-tightening due to cam action between the roller and the body.
It has a crosshatched, serrated finish and clamps tightly against a horizontal back plain. The upper grip is counter balanced so that the specimen can be aligned with the load cell to eliminate non-axial forces. They provide excellent testing accuracy, positive non-slip gripping action and are quick and simple-to-use.
There are two models of Roller grips and depending on the type, samples of 25 – 50 mm wide and 5-6mm thick can be accommodated. Thicker samples will fit but the load axis moves to far from the centre of the mounting hole, also the self-tightening action becomes less effective with thicker samples. Electro-less Nickel plated surface finish are used throughout to provide excellent corrosion and scratch protection.
Principle of Operation
The self-tightening grip uses a serrated eccentric roller type clamping action. The one lever, fast action reduces the time required to load specimens. Specimen insertion is extremely easy and the spring pressures of the roller bracket giving a positive non-slip action gripping force. This is sufficient to hold the material until a load is applied. The follow up action of the roller while under test prevents the specimen from creeping out of the grip as the load increases.
- Fast action for rapid specimen insertion to increase testing throughput
- Positive, non-slip gripping action for accurate results.
- Self-aligning upper grip prevents off-axis loads for consistent test data
- Ideal for testing elastomers, flexible plastics and thin films
- Rugged design for minimum maintenance
- Designed for use in ambient and non-ambient testing conditions
- Available in various versions with test loads of 25, 100, 250 and 400 kN.
- 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.
- Specimen material: Tensile testing of sheet materials, polymers and rubbers by stretching a sample to fracture and recording the relationship between force and extension.
- Specimen shapes: Flat specimen with or without shoulder tab ends.
- Type of loading: Tension. Not suitable for through zero/ reverse stress or fatigue testing.