The present invention relates to reusable bulk transport containers having four wheels attached thereto forming a dolly for easy movement of the containers by a single person. The containers are further equipped with four legs for supporting the containers upright wherein the four wheels are all spaced...http://www.google.com.hk/patents/US5294137?utm_source=gb-gplus-share專利 US5294137 - Transport container with integral dolly
