An improved, self-propelled fork lift having a variable wheelbase, a tilting and leveraged platform, and a translating fork carriage, all under hydraulic control, to permit load positioning for maximum stability, minimum turning radius, and good tractive force despite a relatively low ratio of vehicle...http://www.google.com.hk/patents/US5582501?utm_source=gb-gplus-share專利 US5582501 - Fork lift and method for operating and transporting same
