Although referred to as a Jib Crane, it essentially acts as a structure to hold a manual or electric chain hoist. It’s vital to select a type of jib crane and chain hoist that’s tailored to your operation and intended use. While it’s possible to procure a jib crane and chain hoist from different suppliers, it’s recommended to select a reliable vendor who can provide a comprehensive lifting solution ensuring a technically accurate, fit-for-purpose, and safety-focused solution.
Types of Jib Cranes
Rotational Jib Cranes
Equipped with Chain Hoists A rotational jib crane includes a horizontal track (the jib arm) that extends from a vertical king post situated in bearings. The king post and bearings enable the jib arm to rotate, with the lifting chain hoist typically mounted onto a push travel trolley gliding along the jib arm.
The dual-action of rotational arm and trolley movement allows the chain hoist to be positioned to lift and transport a load to nearly any point within the rotational arc, facilitating load movement in all three dimensions.
Wall-anchored Jib Cranes
These jib cranes have their king post’s bearings anchored to an existing structure like a building, column, or wall. When attached to a wall, the jib crane’s rotational ability is restricted to 180°, while column-mounted units can achieve up to 270° rotation depending on the installation specifics.
During consultations with Granada Cranes technical experts, we will suggest the most suitable jib crane setup for your operational needs, furnish drawings that detail the load impacts on the structure (wall/column) and compute a ‘maximum moment’ force, derived from the cumulative weight of the load and lifting appliance at the jib’s extremity, while also considering the dynamic effects of lifting and lowering loads. These drawings must be validated by a structural engineer, with approval conveyed to Granada Cranes before the installation of a wall-anchored jib crane.
Stand-alone Jib Cranes
A stand-alone jib crane comes with its uniquely designed column and is anchored to the ground upon installation. Substantial floor foundations are necessary to counteract the overturning moment. Its tubular column facilitates a complete 360° rotation, yet it’s crucial to note that when utilised with an electric chain hoist, the power supply must be routed through slip rings, unless stops are integrated to inhibit full rotation.
Low-capacity, short-radius jib cranes can be directly anchored to the floor, provided the floor specification is precisely known, suitable, and in good condition. For larger radius and load capacity jib cranes, casting directly into the floor is a cost-effective mounting option, although relocating it later becomes a less appealing choice. A more favorable installation alternative is a bolted connection requiring a base plate and fixings which necessitate more space around the column base or the employment of chemical anchors.
Under-Supported and Above-Supported Jib Cranes
These types of jib cranes are delineated based on how the cantilevered arm is supported.
An above-supported jib has a tension member extending from the top of the king post to a point around two-thirds down the jib arm. This design yields a lighter structure allowing the chain hoist to get as close as possible to the supporting structure, maximising effective travel. It also enables the utilisation of special track sections in lieu of a rolled beam. The drawback is that more headroom is required for a given lift height. Conversely, an under-supported jib positions the cantilever support below the runway beam, minimising required headroom but necessitating a heavier rolled beam and reducing the maximum effective travel.
In a majority of applications, the jib will rotate, and a push travel trolley will be employed. Extra care is advised, especially if the jib is mounted high, as pushing on the load can cause it to swing away from the vertical center line of the jib. The farther the distance between the load and the jib arm, the more pronounced the swing will be. A more controlled movement alternative would be a powered travel trolley, with options available that furnish powered rotational capabilities for the stand-alone 360° style of jib crane.