The capstan grips incorporate an ingenious double capstan design which provides for fast, easy loading together with a gripping action that results in proper breaks in the full gauge length of the specimen. A split capstan has been arranged so that it can be rotated within a completely separate outer capstan. To load a specimen simply insert an end into the inner split capstan and then rotate this through 360°, and lock in position. This distributes the load over both the inner and outer capstan, thereby minimizing failures at the bite. These grips offer positive relief from the awkward, time consuming capstan loading, and recurring jaw breaks that are usually associated with the testing of seat belts and other high strength belts and tapes.
The snubbing grips and wire drums (spools) are constructed from steel. The grip bodies are designed so that the wire or cable specimen is pulled directly in line with the load cell. By wrapping the specimen around the spools the full load is applied to the spool rather than the specimen like other standard grips.
Each body uses a wire drum (spool) to wrap the specimen around and a clamp to secure the free end of the specimen. The design of wire and cable snubbing grips causes the majority of the tension force to be carried by the spool rather than the clamp, reducing specimen slippage. It also ensures that tension reaches its peak in the free section of the specimen, between the grips.