The utility model discloses a fast positioning's index plate belongs to index plate technical field, including work board, the upper end center position of work board is provided with index plate main part, and the inside center position of work board is provided with the protective cover switch mechanism, the utility model discloses a protective cover switch mechanism has been set up, can effectively protect index plate main part from the
pollution of dust, sundries etc, when not using, and the protective cover main part is lifted through the protective cover switch mechanism, and index plate main part is completely covered and sealed, and the sealing
washer further enhances the protection effect, avoids the problem that the index plate precision is reduced and the service life is shortened because of external factors, simultaneously, and the protective cover switch mechanism adopts the design of bidirectional screw rod and adjusting
assembly, makes the lifting operation of protective cover main part simple, stable and accurate, and the user is convenient to the protection or use of index plate main part quickly, and the maintenance convenience and service life of index plate have been improved greatly.