Stretching apparatus and parts replacement method of stretching apparatus

A parts replacement method of a stretching apparatus comprising steps of:

• (a) preparing a stretching apparatus including:
• a pair of link devices configured to be able to carry and stretch a film and each composed of a plurality of links coupled to form an endless chain;
• a heat treatment unit configured to cover a central portion of the pair of link devices and perform a heat treatment to the film;
• a first link drive mechanism arranged outside the heat treatment unit and on an inlet side of the film and configured to drive the plurality of links;
• a second link drive mechanism arranged outside the heat treatment unit and on an outlet side of the film and configured to drive the plurality of links;
• and
• a link adjustment mechanism arranged outside the heat treatment unit and on the outlet side of the film and configured to reduce a pitch of the plurality of links;
• (b) binding a take-out link group composed of some links included in the plurality of links in a link replacement region located on an outlet side of the film of each of the pair of link devices and carrying out the take-out link group from the link replacement region of the pair of link devices;
• (c) after the (b), arranging a replacement link group in a bound state composed of the same number of links as the take-out link group, on the pair of rails in the link replacement region;
• (d) after the (c), driving the plurality of links such that the replacement link group is advanced to a side of the heat treatment unit and a new take-out link group is pressed into the link replacement region;
• and
• (e) replacing all of the links provided in the pair of link devices by repeatedly performing the step (b), the step (c), and the step (d).