Pivot shaft assembly for a foldable device

A pivot shaft assembly for a foldable device, comprising:

• a pivot base including a base seat, a through hole which extends through said base seat in a first direction, and an engaging portion which is disposed on said base seat adjacent to said through hole;
• a shaft member extending along a central axis through said through hole, said shaft member including a fixed tubular piece which extends through said through hole and which has a fixed tubular wall surrounding the central axis, said fixed tubular piece being pivotably connected with said base seat about a rotating axis which is transverse to the central axis and the first direction, said fixed tubular piece having a radial hole which extends radially relative to the central axis through said fixed tubular wall, said shaft member being rotatable relative to said base seat between a ready position, where said shaft member extends parallel to the first direction, and said radial hole faces said engaging portion, and a swung position, where said shaft member is inclined relative to the first direction by an inclined angle, and said radial hole is remote from said engaging portion;
• and
• a locking member including a locking portion which is movably disposed in said radial hole such that said locking portion is movable radially and outwardly of said fixed tubular wall through said radial hole to engage with said engaging portion when the shaft member is in the ready position, to position said pivot shaft assembly in a locked state so as to prevent rotation of said shaft member relative to said base seat, and such that said locking portion is movable radially and inwardly of said fixed tubular wall through said radial hole to disengage from said engaging portion to make said pivot shaft assembly be in a released state so as to permit rotation of said shaft member relative to said base seat.