An extension drive mechanism for intramedullary extension nails

An extension drive mechanism which enables intramedullary nails used in orthopedic surgery in bone extension nail systems to extend and shorten in the application area and enables the bone to extend or shorten in a controlled manner, the extension drive mechanism comprising:

• a direction control part which has direction control pins on its bottom surface, has rotational movement;
• a bearing housing which is located on the bottom surface of the direction control part and has internal movement surfaces on its internal surface;
• needle bearings which are located within each of the internal movement surfaces in the bearing housing in the form of at least pairs and whose axes are changed by moving by means of the direction control pins;
• bearing springs which are located between the needle bearings and enable the needle bearings to remain separate by pushing each other from the side surface;
• a drive shaft which is located between the needle bearings from the lower end of the bearing housing and rotates clockwise or counterclockwise by the needle bearings;
• and
• a gear motor which is engaged with the upper end of the direction control part and enables the direction control part to be driven in the selected rotational direction for rotating the drive shaft.