The bridge of a top running overhead crane is designed to travel on rails that are mounted onto the runway beams. The beams can be supported by either precisely engineered free-standing columns or by the existing columns of the building.
The bridge of an underhung or under running overhead crane is engineered to travel on the bottom flange of a runway beam. The roof structure of a building typically supports the runway beam in this type of configuration.
This type of overhead bridge crane configuration is made up of a single bridge girder, two end trucks, and a trolley hoist which runs along the bottom flange of the bridge girder between the end trucks.
A double girder overhead bridge crane configuration is made up of two bridge girders, two end trucks, and a trolley hoist assembly. The trolley hoist travels on top of rails that are mounted to the top of the bridge girders.
Another type of hoist and crane configuration similar to the ones listed above is referred to as a Gantry Crane. A gantry crane can be designed with either a Single or Double girder bridge; however the main difference is the gantry girders are attached to legs on both sides of the span. The end trucks at the bottom of the legs allow the crane to travel directly on the ground or on a rails system that can either be load on top of the floor or embedded in the floor. This gantry design eliminates the need for a column or overhead runway system.
There are many applications in which only a trolley hoist assembly is needed; such as a Monorail System. Monorails are generally used in service areas or in applications where the load must follow a predetermined path. The trolley hoist would mount to the bottom flange of the monorail beam just as it would mount to the single girder crane.
Organizations may only require a replacement or upgraded trolley hoist if they currently have an overhead bridge crane solution . The team at Munck Cranes can supply either a new overhead hoist system or a chain hoist, dependent on the application and capacity required. Visit our 2 ton Overhead Crane page to learn more about our capacity crane option.
A Jib crane is another great solution that may fit your specific needs. The jib design is made up of a boom (cantilever) and is mounted to a column. With this design, the trolley hoist assembly can move back and forth across the boom and can be engineered to rotate in a full 360 degrees.