According to the US Patent & Trademark Office, the invention relates to a “crane trolley, especially a single-rail trolley with a short overall height, with a travelling mechanism frame having a hoisting mechanism, which can travel by running wheels on a rail, especially a lower flange of an essentially horizontal beam, wherein at least one running wheel can be driven, and a friction roller interacting with the driven running wheel is arranged on the underside of the rail.”
An abstract of the invention, released by the Patent Office, said: “In order to create a crane trolley that guarantees a reliable reduction in the slippage of the driven running wheel with a simple design, a pair of friction rollers is provided, which may be positioned against the underside of the rail by adjusting the spacing from each other via a common pressing mechanism.”
The inventors were issued US Patent Number 7,234,400 on June 26.
The patent has been assigned to Demag Cranes & Components GmbH, Wetter.
The original application was filed on September 21 2004.
