A load moving device consists of a base member which supports the load to be moved and slides over a surface over which the load is to be moved. A lubricant such as grease is introduced between the base member and the surface and in order to prevent a trail of grease being left when the load is moved...http://www.google.de/patents/US4227197?utm_source=gb-gplus-sharePatent US4227197 - Load moving devices
