Abstract: A shutter rolling mechanism comprises at least two rolling means adapted to roll a shutter around them the rolling means are disposed with their rolling axes parallel and coinciding with each other within an installation space. A driving means is attached to at least one of the rolling means, and a shutter is attached at one end to one of the two rolling means and is disposed so as to roll over one of the rolling means and then over the other rolling means when in stowing action, and to be rolled from the rolling means when in deploying action. The driving means is adapted to drive the rolling means to wind the shutter over the rolling means in one rotational direction and to deploy the shutter in a second rotational direction.

Abstract: An extruder includes a container having a main bore for receiving billets, a die and a piston. The container is formed with at least one gas release vent opening into the main bore at a position intermediate between the extruding end of the bore and a midpoint of the bore's length. Each gas release vent has a valve for allowing selective release of trapped gas. This structure allows venting of gases in such a manner as to allow sequential loading of billets without removal of scrap between them.