seen to separate metal and plastic by cold treatment in the management of the details of the composite metal plastic material

摘要

An article is subjected to a treatment which causes one part thereof to become substantially more brittle than the remainder thereof. One manner of accomplishing this is to cool the article to low temperatures. Either during or subsequent to this treatment the article is subjected to an action which effects separation of the embrittled part from the remainder of the article. This may be achieved by impacting the article, by exposing the article to ultrasonic waves or, in the event that the embrittled part or the remainder of the article is composed of a ferrous substance, by exposing the article to a pulsating magnetic field. A preferred application is to composites consisting of a metal and a synthetic resin where cooling of the article embrittles the synthetic resin. One form of an arrangement for carrying out the method includes a hollow, rotatable cylinder having impacting masses such as steel balls accommodated therein. Inwardly extending projections provided inside the cylinder enable articles to be treated to be agitated as the cylinder rotates. As the cylinder rotates, the embrittled part of each article is comminuted by the impacting action of the masses interiorly of the cylinder. The cylinder is provided with perforations which permit a cooling medium such as liquid air or liquid nitrogen to be introduced into the interior of the cylinder. The perforations also permit the particles of the embrittled parts of the articles to escape and are so dimensioned that the remainders of the articles, which are unaffected by the impacting masses, are unable to escape from the interior of the cylinder. Another form of an arrangement for carrying out the method includes a pair of rollers arranged to move a band, which may be the article itself or a conveyor belt, in an endless path. A device for directing a cooling medium such as liquid air or liquid nitrogen onto the band is arranged adjacent a location of the path and downstream of this location there is provided an impacting device and an abutment member arranged on either side of the path so that the article may be impacted.