Common pivot arrangement of portable computer

A common pivot arrangement mounted on a base member of a portable computer, said base member comprising a plurality of first locating holes and a plurality of second locating holes, said common pivot arrangement comprising:

• a hinge unit, said hinge unit comprising a holder base and a hinge, said hinge comprising a fixed member fixedly mounted to said holder base and a rotatable member rotated about a first axis relative to said fixed member, said holder base comprising a plurality of first through holes corresponding to the second locating holes of said base member respectively and a plurality of second through holes;
• and
• a rotary device, said rotary device comprising a mount and a wheel pivotally mounted on said mount and rotated about a second axis relative to said mount, said second axis is perpendicular to said first axis, said mount comprising a plurality of through holes corresponding to the first locating holes of said base member respectively, said wheel comprising a plurality of mounting holes corresponding to the second through holes of said holder base of said hinge unit respectively.