Workpiece replacing apparatus and machine tool

A workpiece replacing apparatus to deliver a workpiece into an intra-machine space enclosed inside a housing of a machine tool from an extra-machine space outside the housing of the machine tool and to deliver the workpiece machined by the machine tool to the extra-machine space from the intra-machine space, the workpiece replacing apparatus comprising:

• a secured cover comprising a portion of the housing and secured to a securing member of the machine tool, the secured cover defining a partition between the intra-machine space and the extra-machine space, the secured cover having a wall with an inner wall surface facing the intra-machine space and with an outer wall surface facing the extra-machine space, the wall being provided with a cover opening bridging the inner wall surface and the outer wall surface;
• an arm device to deliver the workpiece between the intra-machine space and the extra-machine space through the cover opening;
• and
• a movable cover comprising another portion of the housing and integral with the arm device or in engagement with the arm device, the movable cover being turnable relative to the secured cover about an axis extending parallel to either one of:
• (i) a portion of the inner wall surface adjoining the cover opening, and (ii) a portion of the outer wall surface adjoining the cover opening, such that the movable cover is operable in conjunction with operation of the arm device, the movable cover being configured to close the cover opening with the arm device located in the extra-machine space,
• wherein said movable cover includes a curved plate comprising an arc centered on said axis and disposed centrally in a turning region where the movable cover turns, the curved plate having a curvature defined around a turning center of the movable cover, and said movable cover includes an extended plate extending radially outward from a circumferential end of the curved plate.