Carrier conveying apparatus and heat treatment installment

A heat treatment installation comprising:

• a carrier I/O port for receiving and taking out a carrier which accommodates a substrate;
• a carrier keeping section for keeping the carrier;
• a carrier set-up section where the carrier is set-up for receiving and taking out the substrate;
• a heat treatment apparatus for heat-treatment the substrate;
• a substrate conveyer mechanism for conveying the substrate between the carrier set-up section and the heat treatment apparatus;
• a carrier conveying apparatus for conveying the carrier between the I/O port, the carrier keeping section and the carrier set-up section, the carrier conveying apparatus including:
• a fixed frame arranged so as to extend in a vertical direction;
• a supporting arm adapted so as to move in the vertical direction along said fixed frame, for conveying a carrier having an object to be processed accommodated therein;
• and
• an elevating mechanism arranged between said fixed frame and said supporting arm, for moving said supporting arm to a predetermined position in the vertical direction and maintaining said supporting arm threat so as not to fall down, said elevating mechanism including:
• a guide member arranged on said fixed frame along a vertical direction;
• a fixed surface arranged in parallel with said guide member, said fixed surface being provided, thereon, with an engagement projection;
• an elevating body guided so as to rise and fall along said guide member, for supporting said supporting arm;
• a braking body pivotally supported by said elevating body in a vertical plane, said braking body being in a position apart from said fixed surface under a normal condition of said braking body and being rotated in a direction approaching said fixed surface from an underside of said elevating body when said elevating body falls, whereby said braking body is engaged with said fixed surface to brake said elevating body, said braking body including:
• a shaft for allowing said braking body to be rotated;
• an engagement member arranged so as to project from said shaft radially outward, said engagement member having a leading end thereof formed for engagement with said engagement projection on said fixed surface;
• and
• a suspension member winding part about which said suspension member is wound, said suspension member winding part being provided on said shaft;
• urging unit for urging said braking body so as to rotate to the direction approaching said fixed surface from the underside of said elevating body;
• a suspension member connected to said braking body, for suspending said elevating body through an intermediary of said braking body, said suspension member, owing to its tensile strength to suspend said elevating body, also rotationally urging said braking body in a direction to separate said braking body from said fixed surface in opposition to rotating force due to said urging unit;
• and
• a stopper for stopping the rotation of said braking body due to the tensile strength of said suspension member;
• whereby, when said suspension member is cut off, said braking body to which urging force due to the tensile strength of said suspension member is not applied any longer is rotated against said fixed surface by said urging unit, so that said elevating body can be braked from falling.