The decisions of this Court require the conclusion that reconstruction of a patented entity, unpatented elements, is limited to such a true reconstruction of the entity as to "in fact make a new article," after the entity, viewed as a whole, has become spent. In order to call the monopoly, conferred by the patent grant, into play for a second time, it must, indeed, be a second creation of the patented entity. …Mere replacement of individual unpatented parts, one at a time, whether of the same part repeatedly or different parts successively, is no more than the lawful right of the owner to repair his property.