GB1339433A - Impulse torque decay test insbrument - Google Patents

Abstract

1339433 Measuring stress relaxation: measuring stress electrically B F GOODRICH CO 27 Nov 1970 [28 Nov 1969] 56570/70 Headings G1N and G1S An apparatus for testing stress relaxation comprises a pair of dies 14, 37 between which a sample may be confined under pressure, driving means 31, 33, 35, 36, for applying impulsively a predetermined degree of rotation to one of the dies 37 and torque sensing means 45 operatively connected to the movable die and to a recorder 50 providing a time base for registering the stress relaxation of a sample confined between the dies. Pressure is applied to the sample by means of a piston and cylinder 17, 18 moving a platform 25 towards and away from the static die 14. Platform 25 carries the moving die, the driving mechanism and a load cell 45. Die 37 is rotated by piston and cylinder 31 acting through piston rod 33 and lever 35. The stroke of the piston and hence the degree of rotation applied to the sample is determined by the position of nut 41 on threaded piston rod 33 co-operating with a bracket 38. The rotation, of between 1 degrees and 4 degrees, is applied to a sample within 10 milliseconds and maintained until the stress measured by the load cell decays to a preselected standard amount for comparison with other samples.