Patent ID: 7402108

Claim:
A flexible shaft coupling, comprising: a first hub for connection to a transmission shaft, said first hub having a cylindrical part, an outwardly extending flange at one end of said cylindrical part and a plurality of spring holes each extending in the direction of a coupling axis with the transmission shaft, said spring holes extending through said flange and being circumferentially spaced along the periphery thereof; a second hub for connection to another transmission shaft, said second hub having a cylindrical part and an outwardly extending flange at one end of said cylindrical part; a cover fixed to said flange of said second hub so that said flange of said first hub is accommodated therein, said cylindrical part of said first hub extending into said cover, and said flange of said first hub and each of said flange of said second hub and said cover having a space there between sufficient to accommodate shaft misalignments; spring supporting pins extending in the direction of the coupling axis and supported between said flange of said second hub and said cover; and a plurality of coil spring sets each comprising multiple barrel-shaped coil springs, each of said barrel-shaped coil springs having a center diameter which is larger than a diameter of either of its ends, each of said barrel-shaped coil springs being located in one of said spring holes and supported in the one of said spring holes by a corresponding one of said spring supporting pins so that said barrel-shaped coil springs in each of said coil spring sets have adjoining end faces in contact with or able to exert a force on one another, and in series with each other, a largest-diameter portion of each of said barrel-shaped coil springs being clearance fitted in the one of said spring holes and a smallest-diameter portion of each of said barrel-shaped coil springs being interference fitted over the corresponding one of said spring supporting pins, and said barrel-shaped coil springs being compressed between said cover and said flange of said second hub so that when torque is transmitted between said first hub and said second hub via said barrel-shaped coil springs, said barrel-shaped coil springs deform and adjoining coils of said coil springs come into contact with each other, with friction resulting from the contact causing said coil springs to absorb shocks and reduce torsional vibration.