Breakage preventing device for tilting table indexing device

A breakage preventing device for a tilting table indexing device,

• wherein the tilting table indexing device includes
• a rotary member having a table and a rotary shaft, the rotary shaft extending in an extending direction of the table and being integral with the table, and
• a frame having a pair of supporting devices and a pedestal, the supporting devices supporting both sides of the rotary shaft and mounted on the pedestal,
• wherein at least one of the supporting devices has built therein a direct-drive motor and a holding mechanism, the direct-drive motor driving the rotary shaft for indexing an angle of the rotary shaft, the holding mechanism holding the angle of the rotary shaft, and
• wherein during an indexing operation of the table, the rotary shaft is rotated by the direct-drive motor to a desirable angle within a predetermined normal rotation angle range to tilt the table, and the tilt angle of the tilted table is held by activation of the holding mechanism,
• wherein the breakage preventing device comprises an elastically displaceable member and an engaging portion, the elastically displaceable member provided at one of the rotary member and the frame and having a pressure receiving surface, the engaging portion provided at the other of the rotary member and the frame, the pressure receiving surface and the engaging portion provided so as to contact each other when at least the rotary shaft rotates beyond the normal rotation angle range, and
• wherein when the rotary shaft rotates beyond the normal rotation angle range because of free rotation of the rotary member in an emergency, the pressure receiving surface of the elastically displaceable member contacts the engaging portion provided at the other of the rotary member and the frame, is elastically displaced, and absorbs the kinetic energy of the rotary member to stop the rotary member during the free rotation before a danger angle range while the pressure receiving surface of the elastically displaceable member is elastically displaced.