Fixed position, fixed frequency pendular-type vibration absorber with frequency linearization

Claim 1

A fixed frequency vibration absorber adapted to be fixedly attached to a vibration prone system to cooperate with the principal vibration excitation source which primarily generates vibrations in a given direction so as to control system vibrations and comprising: base means, two mass means of selected equal mass, pendular connecting means, having a pendular arm of length "a", connecting said mass means in opposed positions to said base means for support from and allochiral pendular motion in said given direction. spring means operatively connected between said mass means in selectively preloaded condition to exert a force "Fnr"on said mass means to establish the desired natural frequency thereof, and to also cause said mass means to move in coincident, allochiral pendular motion so that motion of said mass means produces additive forces in said given direction to absorb the vibration force established by said principal source, and so that all other forces so produced mutually cancel, said spring means also being of selected spring rate "Ks" to compensate for the spring rate reduction caused by pendular motion of the pendular connecting means and thereby provide an essentially linear spring rate acting on said mass means for angles of pendular motion "θ" of at least ±45°, so that the natural frequency of the vibration absorber is substantially constant throughout this range of operation, and wherein "Ks" is selected according to the equation: ##EQU3##