Various forms of businesses having a need for a tractor equipped with a three-point hitch and for a backhoe also have a need for a crane. However, many of these businesses, while requiring frequent use of the tractor and/or backhoe, require only infrequent use of a crane. Accordingly, many businesses of this type do not incur the expense of purchasing and maintaining a crane, but rather rent a crane when the use thereof is needed.
While such business conduct may be looked upon as representing a considerable savings, more than very infrequent rental of a crane can amount to considerable expense over a period of time. Accordingly, a need exists for structure whereby a tractor equipped with a three-point hitch, or a backhoe, may be transformed, through the utilization of a crane attachment, into a mobile crane, the crane attachment representing only a small fraction of the expense of a self-propelled crane and an even less proportion of the expense of maintaining a self-propelled crane.
Various forms of self-propelled vehicles have been heretofore provided with crane attachments, but most of these are not well suited for heavy-duty crane use. Examples of various forms of crane attachment equipped self-propelled vehicles are disclosed in U.S. Pat. Nos. 1,423,724, 2,903,142, 2,914,203, 3,276,603, 3,373,885 and 3,527,362.