Calculator keyboard mfr. - where conducting contacts e.g. of silicone rubber are positioned in heated mould and non-conducting silicone rubber is injected

摘要

An injection moulding is produced in different rubber materials, in partic. a switching contact sheet with conducting and non-conducting materials for the keyboard of calculators. Separately made parts of one material are placed at suitable points in an injection mould cavity and are hot bonded to a second material which is injected into the cavity. Good bonds are obtd. with no manual operations required in its prodn.