Overload protection device and high-speed dental handpiece comprising same

A high-speed dental handpiece, comprising:

• a dental handpiece body having a driving air tube;
• a side tube being in fluid communication with said dental handpiece body and having one end attached to said driving air tube and an opposite end;
• and
• an overload protection device connected to said opposite end of said side tube,
• wherein said overload protection device comprises:
• a valve body, having a first end, a second end opposite said first end, an inner wall, and an outer surface so as to form an air chamber, an air intake passage between said first end and said air chamber, and a communication location between said air chamber and said air intake passage, said opposite end of said side tube being connected to said air intake passage,
• wherein said valve body is comprised of a plurality of air discharging holes in said communication location;
• a piston, having an outer piston surface and being movably positioned within said communication location of said valve body;
• an elastic member, being positioned within said air chamber between said piston and said second end;
• and
• a valve plug being arranged at said second end of said valve body,
• wherein the said elastic member is arranged between the said piston and the said valve plug, and
• wherein said piston has a closed position within said communication location so as to cover said air discharging holes from within said valve body and an opened position between said communication location and said valve plug so as to uncover said air discharging holes, said piston being actuated between said closed position and said opened position according to said elastic member.