Pneumatic Grips

Pneumatic grips are often a preferred means of holding a sample for tensile testing because the gripping pressure can be controlled precisely and because deformation of the specimen does not produce any change in the gripping pressure. Pneumatic action grips are excellent at holding materials and products that 'flow' or 'creep, during a test as the gripping jaw face exhibits a fast follow through action that keeps the side pressure on the test sample constant through the test. Also, because of the fast opening/closing action that is foot-switch operated it is very quick to change sample. This minimises delay in repeat testing.

The grips are operated from an existing compressed air source that has an output regulator capable of maintaining the output pressure at a user set value up to 10Bar maximum pressure. The pressure used determines the constant side pressure applied by the jaw face. Adjustment of the air pressure enables the optimum holding force to be used for a specific sample, thereby minimising sample damage and grip breaks (i.e. the sample breaking where it exits the grip). 

The footswitch can be adjusted to either close or open the pneumatic grips when pressed. It will normally be supplied to OPEN the grips when pressed but the user must check this before touching the grips.

The Pneumatic Grips are supplied with a length of blue coloured pneumatic tube approx. 4 metres long. This is to be cut to length to connect the components together as shown in the diagram. The tube simply pushes into the fitting to make an air tight joint. It can easily be removed by holding the blue outer ring of the fitting inwards and pulling the tube out.

These grips are used in standard methods such as: PSTC 4B, AFERA test method no. 5004.

Materials that can be held and gripped without sample failing at the grip face.

• Pneumatic grips are often a preferred means of holding a sample for tensile testing because the gripping pressure can be controlled precisely, and because deformation of the specimen does not produce any change in the gripping pressure.
• This type of grip clamps the specimen by lever arms that are actuated by compressed-air cylinders built into the grip bodies. A constant force maintained on the specimen compensates for decreases in force resulting from creep of the specimen in the grip.  Another advantage of this design is the ability to optimise gripping force by adjusting the air pressure, which makes it possible to minimise specimen breaks at the grip faces.
• 10Bar maximum operating pressure.
• Compressor not included.

Full installation instructions are provided within the Education Zone of the latest Exponent/Connect software version and on the technical information sheet accompanying this product.

Stable Micro Systems probes and attachments are commonly made from four materials: anodised aluminium (AA6082 T6), stainless steel (316 T), Delrin (acetyl copolymer) and Perspex (polycarbonate).

In general use, probes and attachments made from these materials will be suitable for testing food products and inert non-food materials.

The four materials listed above are not universally resistant to all types of chemicals and as such the compatibility of the probe/attachment material with the product (to be tested) must be established to prevent damage to the probes and attachments. If the compatibility of the product with the probe is unknown to the customer then the chemical information about the product (Material Safety Data Sheet or Product Data Sheet) should be submitted to Stable Micro Systems. Stable Micro Systems will then assess the suitability of the probe/attachment material for use with the product and advise accordingly. If this advice is not sought then Stable Micro Systems will not accept liability for probes/attachments damaged by chemical attack from the product being tested.

All probes and attachments may be cleaned in warm (or hand hot) water using a mild detergent. A soft brush may be used but abrasive cleaning aids should be avoided. Stable Micro Systems products should not be microwaved or cleaned in a dishwasher.

Screw threads should be lightly lubricated after drying using a light lubricant, e.g. petroleum jelly, mineral oil. This will aid the fitting and unscrewing of the item. Each component of a probe or attachment should be wrapped separately when stored, to avoid scratching or chipping. This will safeguard against any unnecessary damage to the accessory.