Shaft lock device with coil spring inserted in rotational shaft of hinge mechanism and portable information processing apparatus with shaft lock device.

摘要

A shaft lock device includes a cylindrical rotational shaft (26), and first and second members (28, 24). The first member (28) supports one end of the rotational shaft so that the shaft (26) is rotatable around the axis thereof, and the second member (24) is fixed to the other end portion of the shaft and rotatable integral with the shaft (26). A coil spring (38), coiled in a predetermined direction and having a coil diameter greater than the inner diameter of the shaft, is arranged in the shaft along the axial direction while the outer surface of the spring is pressed against the inner circumferential surface of the shaft (26b). When the second member (24) is rotated in the direction opposite the coiling direction, the spring (38) is urged to expand in its radial direction, thereby retaining the shaft (26) from rotating. When the second member (24) is rotated in the coiling direction, the spring (38) is urged to contract in its radial direction, thereby allowing the shaft (26) to rotate.