PURPOSE: To reduce the force exerted on the other follower on the opposite side by securing the exertion of merely small force of the follower an one side to a guide rail.

CONSTITUTION: Two side faces fitting brackets 10.1 and 10.2 each having a roller 28.1 or 28.2 are fitted to a base plate 33. The base plate 33 is fixed to the cage attaching metal of a skip or the attaching frame. Three rollers are brought into contact with a guide rail 40 known even as a silk that guide. The force exerted on the guide rail 40 by the roller 28.2 is added to the force exerted on the roller 28.1. In this way, by securing the exertion of merely small force of the roller 28.2 to the guide rail 40, the force exerted on the roller 28.1 can be reduced.