Moving heavy loads is challenging and often unsafe for personnel in workshops, warehouses or light industries. If the full overhead crane is not feasible, a gantry crane is an effective alternative. This article describes what a gantry is, where it is used and some considerations prior to purchasing for business use.
What is a Gantry?
A gantry is a freestanding structure composed of legs and a beam. A hoist or chain block is mounted on the beam to enable movement of a load vertically and horizontally. Unlike an overhead crane, a gantry does not rely on the building structure for support and is, therefore, ideal for use in buildings where roof and walls cannot carry additional loads.
Common Types
Portable gantries are generally lightweight, movable to where they are required and can be adjusted to serve a variety of functions. Some can also be collapsed for easy transport and storage. Fixed gantries are not movable and are designed for a permanent position.
When selecting a design, it is prudent to compare a range of lifting gantry systems to appreciate the differences in capacity, height and span.
Where Gantries Help Most
Gantries can be found in many types of engineering workshops, vehicle service bays, fabrication shops, plant rooms, and warehouses. Common applications include moving machine components, loading components onto/into vehicles, and positioning heavy tooling. Gantries eliminate or reduce manual handling, which is a key contributor to work related musculoskeletal injuries. Gantries can increase the productivity of a workforce by reducing the time it takes to perform a repetitive task.
Gantries are also suitable for businesses which have a flexible or changing workspace. A unit can easily be moved from one workbench to another or from a workbench to a loading bay.
Determining the Right Capacity
When determining the capacity of a gantry crane, the maximum load plus the weight of the hoist and any rigging must be considered. Choose a capacity which comfortably exceeds this load. The capacity of a crane can be reduced if the span of the crane is increased. It is important to consider the centre of the load in relation to the span of the crane as this too can reduce capacity.
The height of the load must be considered as well. A gantry crane must also pass through doorways and aisles.
Floor Conditions
The floor on which a gantry crane stands must be firm and level. If the floor is not level this can cause the gantry frame to tilt. If the floor is not firm, this too can cause wheels to jam. When a heavy load is lifted, locking castors or stabilisers must be used as well as braking the wheels.
SAFETY AND COMPLIANCE
In the UK, lifting gantries must meet the requirements of the Lifting Operations and Lifting Equipment Regulations. This means the hoist must be suitable, correctly identified and thoroughly examined at regular intervals (typically annually) by a competent person. The same requirement applies to lifting machinery. The hoist, slings and accessories also require examination.
Operators must be trained to understand the safe working load and the consequences of exceeding this limit. Gantries must not be used to drag loads sideways and must not be loaded in a manner which causes the load to swing. Keep the area beneath the load clear.
TIPS FOR MAINTENANCE
Inspect the gantry before each use to ensure bolts are not loose and that components have not been damaged. Also check hoist chains and ensure moving parts are not restricted and are lubricated. Store the gantry indoors to prevent corrosion. Record all examinations to show compliance if required.
THE BOTTOM LINE
For the safe movement of heavy items, permanent overhead structures are often unnecessary. However, choosing the right gantry to meet the capacity, span and height requirements means that the gantry will provide safe and reliable service for many years and improve the working environment by saving time and effort and improving the safety of employees.