Collet lock for a mold assembly

In combination with a mold having two mold parts movable between an open position spaced from each other and a closed position sealingly contacting each other, a mold locking mechanism for securely clamping said mold parts in said closed position, comprising:

• an elongate tie rod extending between said mold parts and supported on said one mold part by first mounting means, said tie rod having first locking means thereon at a location spaced from said one mold part;
• second locking means provided on the other of said mold parts and cooperable with said first locking means on said tie rod for preventing lengthwise movement of said tie rod relative to said other mold part, said second locking means including a plurality of locking members disposed at angularly spaced locations about the axis of said tie rod and supported for movement toward and away from said tie rod axis between retracted and locking positions, said tie and being received between said locking members when said mold parts are in said closed position, and each said locking member, when said mold parts are in said closed position and said locking members are in said locking position, being engaged with said first locking means on said tie rod;
• means for effecting movement of said locking members between said retracted and locking positions;
• and
• selectively actuable means for resisting movement of said locking members away from said locking position,
• said second locking means including a collet having a sleeve which surrounds said tie rod axis and is fixed against movement relative to said other mold part in a direction parallel to said tie rod axis, said tie rod being received within said sleeve when said mold parts are in said closed position, said sleeve having therein a plurality of peripherally spaced slots extending substantially axially from one end thereof and defining a plurality of axially extending arms which are resiliently flexible in directions substantially perpendicular to said tie rod axis, each said arm having a said locking member thereon adjacent said one end of said sleeve and on the side thereof facing said tie rod axis.