bent and the limit switch 22 is turned off when the limit switch 22 is off the operation of the inverter 24 is stopped to increase the speed of the motor 2 when the flexible lever 20 passes beyond the point p2 the shuttle 14 is running within the shed c and the shed c is maintained at full open position this motion corresponds to the section between the point p2 on left side and the point p3 in fig6 a and corresponds to the section between the angles 90 and 180 degrees in fig6 b when the shuttle box 10 moves to the position where the flexible lever 20 is in contact with the point p3 of the extension bar 18 the moving direction of the shuttle box 10 is changed and the shuttle box 10 starts to move foreward while the shuttle box 10 is moving between the first position in which the flexible lever 20 is in contact with the point p3 and the second position in which the flexible lever 20 is in contact with the point p2 the limit switch 22 is off and the rotating speed of the motor 2 is high in this period the shuttle 14 is still located within the shed c and the shed c is maintained at full open position this motion corresponds to the section between the point p3 and the point p2 on right side of fig6 a and corresponds to the section between the angles 180 and 270 degrees in fig6 b when the.