Link mechanism, link device, and stretching machine

A link device used in a stretching machine configured to stretch a film, the link device comprising:

• rails;
• and
• a plurality of link mechanisms coupled to constitute an endless chain and configured to move along the rails,
• wherein each of the link mechanisms includes:
• a base member;
• an outer rail holder provided on one end side of the base member in a longitudinal direction and including a plurality of guide rollers moving along a first rail;
• an inner rail holder provided on the other end side of the base member in the longitudinal direction and including a plurality of guide rollers moving along a second rail provided on an inner side of the first rail;
• a link plate having one end in a longitudinal direction rotatably coupled to the outer rail holder and the other end in the longitudinal direction rotatably coupled to another link mechanism;
• and
• a clip provided on the one end side of the base member in the longitudinal direction where the outer rail holder is provided and configured to grip the film,
• wherein the plurality of guide rollers in the outer rail holder include a guide roller moving on an outer side of the first rail and a guide roller moving on the inner side of the first rail,
• wherein the outer rail holder includes a roller holding portion configured to rotatably hold the guide rollers, and
• wherein the outer rail holder includes a roller cover composed of a first cover member that is removably attached to the roller holding portion and covers the guide roller moving on the outer side of the first rail, and a second cover member that is removably attached to the roller holding portion and covers the guide roller moving on the inner side of the first rail.

A stretching machine configured to stretch a film, the stretching machine comprising:

• a pair of link devices configured to convey and stretch the film,
• wherein each of the link devices includes rails and a plurality of link mechanisms coupled to constitute an endless chain and configured to move along the rails,
• wherein each of the link mechanisms includes:
• a base member;
• an outer rail holder provided on one end side of the base member in a longitudinal direction and including a plurality of guide rollers moving along a first rail;
• an inner rail holder provided on the other end side of the base member in the longitudinal direction and including a plurality of guide rollers moving along a second rail provided on an inner side of the first rail;
• a link plate having one end in a longitudinal direction rotatably coupled to the outer rail holder and the other end in the longitudinal direction rotatably coupled to another link mechanism;
• and
• a clip provided on the one end side of the base member in the longitudinal direction where the outer rail holder is provided and configured to grip the film,
• wherein the plurality of guide rollers in the outer rail holder include a guide roller moving on an outer side of the first rail and a guide roller moving on the inner side of the first rail,
• wherein the outer rail holder includes a roller holding portion configured to rotatably hold the guide rollers, and
• wherein the outer rail holder includes a roller cover composed of a first cover member that is removably attached to the roller holding portion and covers the guide roller moving on the outer side of the first rail, and a second cover member that is removably attached to the roller holding portion and covers the guide roller moving on the inner side of the first rail.