Pneumatic feeding and returning device

The invention discloses a pneumatic feeding and returning device. The pneumatic feeding and returning device comprises a bottom plate, second air cylinders, a first air cylinder, a supporting block, fixing blocks, clamping plates and connecting blocks; a machining groove is formed in one side of the outer wall of the upper end of the bottom plate, a supporting rod is installed on the outer wall of the side, away from the machining groove, of the bottom plate, the first air cylinder is installed on one side of the outer wall of the upper end of the supporting rod, the supporting block is installed on the outer wall of one end of the first air cylinder, and movable holes are symmetrically formed in one side of the upper end of the inner wall of the supporting block; and the fixing blocks are installed on the two sides of the outer wall of the lower end of the supporting block, and embedding grooves are formed in the outer walls of the opposite sides of the two fixing blocks. According to the pneumatic feeding a