FLEXIBLE SHAFT COUPLING

A flexible shaft coupling comprises a first and a second hub (1, 11) each having an outwardly extending flange (4, 14) at one end of their cylindrical part (2, 12) and being connectable to a transmission shaft, the first hub (1) having a plurality of spring holes (6) perforated through and along the circumference of its flange (4) thereof; a holder (21) fixed to the flange (14) of the second hub (11) so as to contain the flange (4) of the first hub (1), with the cylindrical part (2) of the first hub (1) passing therethrough the holder (21), with a space large enough to accommodate shaft misalignments left between the flange (4) of the first hub (1) and each of the second hub (11) and holder (21); barrel-shaped coil springs (35) passing through the spring holes (6) provided in the flange (4) of the first hub (1), the barrel-shaped coil springs (35) being compressed between the flange (14) of the second hub (11) and the holder (21) so as to deflect on transmission of torque and bring the adjoining coils thereof into contact with each other, with the largest-diameter portion (36) of the barrel-shaped coil springs (35) being tight-fitted in the spring holes (6) in the first hub (1) and the smallest-diameter portions thereof being tight-fitted over pins (31) supported between the flange (14) of the second hub (11) and the holder (21).