| 摘要 |
The machine comprises a fixed head and a mobile head rigidly joined to an inertial body, between which the test piece is placed and attached by its ends, surrounded by a temp. conditioning chamber. - A pendulum formed from the test piece, the inertial body and the mobile head provides the torsional oscillations or vibrations whose period or frequency of vibration is measured by a fixed photo-electric device illuminated by a fixed light source, the light path passing through a diaphragm in the inertial body and another fixed diaphragm. - The instrument registers an alternating current superposed on a continuous current and can measure the damping of the plastic material, by the use of suitably shaped diaphragms, e.g. bounded by arcs of circles centred on the axis of oscillation and radii. - The test piece may be disengaged when required. - The instrument can be used not only to measure the modulus of torsion but also the damping of a plastic without being effected by the change in zero point which occurs.
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