Typical castor chair appratus(Principle and Test Apparatus )
Principle :
1.A textile floor covering is submitted for a prescribed number of cycles to the the action of three castors which produce an eccentric turning motion.
2.At the end of each test :
The change in appearance in accordance with en 1471 is assessed after 5000 cycles and 25000 cycles (Test A).
The change in colour by means of grey scales is assessed after 750 cycles (Test B).
The extent of deterioration of the specimen is assessed after 10000 or 25000 cycles (Test C).
1. Circular, rotating testing platform, of diameter(800±5)mm on wirch the specimen support plate is mounted. The rotation speed of the testing platform shall be 19r/min and the direction of rotation shall reverse at (180±20)s intervals. The stop time between reversals be (5±1)s.
2. Castor assembly,comprising a vertical shaft set in a bearing and a plate,R,on which the castors are mounted. This castor assembly is offset at a distance of 198 mm from the centre of the testing platform.
3. The three castors 5.3 are arranged concentrically at 120°intervals around the centre of the plate and at a distance of 130 mm from the centre of the plate. They are free to rotate so that they follow the rotation of the castor assembly. The rotation speed of the castor assembly shall be (50±1) r/min.
The castor assembly when loaded has a mass of (90±1) kg this is divided equally over three castors.
The distance under load between the castor assembly plate R and the load drive C (castor plate clearance ) shall be more than 3 mm at the point of measurement.