Method and apparatus for testing and/or adjusting vibration absorber for suspended cables
AssigneeSlater Steel Industries Limited
InventorsOlaf Nigol, Herbert J. Houston
Life of this patent
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Abstract
A pendulum type vibration absorber tester/adjuster, which enables vibration absorbers to be set to a desired damping in the factory. The test/adjustment is effected by mathematically determining the pendulum weight and arm length, setting the pendulum into motion and recording the motion on a chart recorder, and adjusting the damping of the absorber until a predetermined decrement is obtained.
Claims12
A method for testing and/or adjusting a vibration absorber to be used to absorb vibration from a suspended cable, comprising the steps of:
- determining the desired damping of said absorber, the desired oscillation frequency at which the test is to be conducted, and the tension and mass per unit length of the cable from which vibration is to be absorbed;
- selecting a logarithmic decrement value to be utilized for test purposes;
- providing a pendulum to be used as a mechanical analog of the suspended cable-vibration absorber system;
- adjusting the weight and radius of gyration of said pendulum to cause said pendulum to oscillate at said frequency and with said logarithmic decrement when said damping factor has said desired value;
- coupling said vibration absorber to said pendulum to damp the oscillation thereof;
- setting said adjusted pendulum into oscillation;
- and
- displaying information responsive to the sensed amplitude and indicative of the logarithmic decrement of said oscillation.
Apparatus for testing and/or adjusting a vibration absorber to be used to absorb vibration from a suspended cable, comprising:
- a pendulum;
- means for adjusting the weight and radius of gyration of said pendulum;
- means for coupling said vibration absorber to said pendulum so as to damp any oscillation of said pendulum;
- means for sensing the amplitude of oscillation of said pendulum;
- and
- display means coupled to said sensing means for displaying information indicative of the logarithmic decrement of said oscillation.
A method for adjusting a vibration absorber to be used to absorb vibration from a suspended cable, comprising the steps of:
- providing a pendulum having a radius of gyration and weight sufficient to cause the pendulum to oscillate at a desired test frequency with a selected logarithmic decrement when coupled to a vibration absorber having a desired damping factor;
- coupling said vibration absorber to said pendulum to damp any oscillation thereof;
- setting the pendulum into oscillation;
- and
- adjusting the damping factor of said vibration absorber to cause the logarithmic decrement of said oscillation to be substantially equal to said selected logarithmic decrement.
Dependencies are inferred from the claim text.