Arm is used in teaching

The utility model provides an arm is used in teaching, include revolving stage, forearm and with forearm articulated postbrachium, the postbrachium is formed by the assembly of acrylic transparent board, it includes first fixed plate, the second fixed plate, the first arm board, second arm board and pull rod, be equipped with the rotary drum between the one end of the first arm board and second arm board, it fixes the outside at the first arm board to be equipped with the 5th motor, the one end of the output shaft follow rotary drum of the 5th motor stretches into in the rotary drum, the intermediate position of rotary drum is equipped with the breach groove, pull rod one end is articulated with the one end of curved bar, the other end of curved bar stretch into in the rotary drum through the breach groove and with the output shaft of the 5th motor, a second fixing plate, be equipped with first articulated shaft between the other end of the first arm board and second arm board, the forearm is articulated with