Abstract: A machine for preparing and introducing closure sliders inside annular hollow members for producing spring safety catches for necklaces and the like, consisting of two operative unitsets, each comprising a table rotatably mounted about a vertical axis and actuated by means for rotating the table intermittently through angles of 90.degree. and carrying four radially reciprocating pliers units spaced apart from each other of 90.degree.

Abstract: A process for obtaining a nacre effect on surfaces of gold, silver or alloys thereof, consisting in:Heating the metal having the highest purity degree up to a temperature higher than its melting point;Pouring of the molten material into a mold at a temperature compatible with the resistance of the mold;Allowing the material to cool into the mold;Performing a surface treatment on the article surfaces or portions thereof, where the nacre effect has to appear;Dipping the obtained article into an electrolytic bath including organic and/or inorganic salts, using a very low current density; andCarefully washing the obtained article.

Abstract: Apparatus for inserting helical springs into annular safety catches including a revolving table, four pliers units positioned on the periphery of the table, a first station for feeding catches, a second station where a helical spring is inserted in a catch, a third station where the ends of the catch are brought into coplanar position, and a fourth station with a sensing head where the end product is checked with provision to separate out faulty products.