The utility model relates to a protector of overload protection device top board especially relates to a clamp plate safety shield, its including fixed together preceding lid, go up lid, lid, right cover body and left lid down, preceding lid, go up the lid, lid and right cover body constitute without male offspring the lid and do not have the four directions cover body of left side lid down, the left end face of preceding lid, go up the lid the left end face, down the left end face of lid all be equipped with the flat straight chute who extends right, the right -hand member face of left lid is equipped with corresponding match's the slide one by one with three flat straight chute. Owing to implement above -mentioned technical scheme, this application is through the left lid of pull or propelling movement right left, changes left lid and right cover body's relative pitch to change the length of this application, the rethread magnetic sheet adsorbs this application to be shielded cashier's office in a shop at secondary equipment, can cover one protection or a plurality of clamp plates to guarantee on -the -spot safety, prevent to miss and bump, miscarry and move back, protection pressing plate, electric wire netting safety and service reliability when improving the secondary equipment maintenance.