Jib Cranes and Gantry Cranes are good alternatives to an overhead crane where a small area is being covered and light loads are being lifted:
The Jib Crane:
The Jib crane is a type of crane that has a rotating horizontal boom attached to a fixed support. A standard trolley equipped with electric or hand-geared chain hoist normally operates on the lower flange of the jib crane boom.
Jib cranes may be appropriate for servicing machinery located outside of the coverage of an overhead crane, or for assembly lines where jib boom areas can overlap for staged operations.
Jib cranes may be floor mounted or supported by the building frame. Floor mounted jib cranes are generally preferred. Jib cranes which must be supported by the building frame may be mounted directly to the building column or mounted to a supplemental column.
The floor-mounted jib crane requires no top braces or supports of any kind from the building structure. The jib boom will rotate through a full 360 degrees. Under ordinary conditions, these base-mounted jib cranes can be anchored directly to a properly-designed reinforced concrete floor or separate foundations.
The column-mounted jib crane is generally mounted on a building column. The boom rotation is limited to approximately 200 degrees.
The application of a column-mounted jib crane requires that the building column, column base anchorage and bracing be designed to account for the special loads imposed by the jib crane. This will usually increase the building column size.
The Gantry Crane:
Gantry cranes are adapted to applications where overhead runways would be very long and costly to furnish. They are also appropriate where overhead runways would interfere with handling operations, storage space, or service areas.
Single-leg gantry cranes are used in those installations where it is convenient to have one end of the bridge supported on an overhead runway rail and the other end supported on a gantry leg. This design can then utilize adjacent building framing to support the overhead runway rail. This application requires that the building framing, column base anchorage and bracing be designed to account for the special loads imposed by the gantry crane.