Patent ID: 7090300

Claim:
A low frequency vibration seat, comprising: a cushioning member disposed at a contacting portion with a human body; a vibration control section formed with a spring mechanism, of which spring constant k is set to be 0<k≦20 N/mm in at least a predetermined displacement range to make a low frequency vibration arise in said cushioning member; and a flat-type supporting member, connected to said spring mechanism at the rear end thereof, and supported to a frame member positioned in front of a cushion frame at the front end thereof, and biased backwards by said spring mechanism, and disposed under said cushioning member; wherein the spring mechanism forming said vibration control section is formed by serially connecting a plurality of spring members different in spring constant, and disposed in the rear of the seat cushion; among the spring members forming said spring mechanism, a spring member relatively low in spring constant mainly works until a statically equilibrium state is obtained after a person takes a seat on said cushioning member; and when vibration is inputted, the plurality of spring members connected in series work together, the composite spring constant of the spring members has a lower value than that of said spring member relatively low in spring constant, the composite spring constant has a value in the range of 0<k≦20 N/mm in at least a predetermined displacement range.