The Swiss franc pushed higher against the dollar on Friday adding to four straight sessions of gains and hitting its highest since early May after the US Federal Reserve said it would extend its bond buying programme. The franc rose 0.2 percent against the dollar compared to the New York close, trading at 0.9218 francs per dollar after hitting a seven month high against the single currency. The franc fell 0.1 percent against the euro, to 1.2082 francs per euro.