Material handling is a critical part of any manufacturing operation, and choosing the right equipment is important for worker safety and productivity. Material handling equipment can be broken down into two main categories: overhead and on-floor movers. Both systems can be important to the manufacturing process, but each type has its advantages and disadvantages.
On-floor movers generally include industrial hand trucks, forklifts, and fixed conveyor systems, while overhead movers include cranes, hoists, and monorails. First, let’s look at the various types of on-floor movers.
Industrial trucks are cost-effective, unfixed material handling systems that can move materials along several paths in any direction. These systems aren’t just cost-effective to purchase, they are also easier to maintain than larger, fixed systems. However, industrial trucks like forklifts and walkies require a lot more floor space to move and store than overhead systems. In fact, some overhead systems don’t require any floor space at all. The load carrying capabilities of hand trucks are also limited because of weight constraints and the size/shape of materials.
Conveyors, on the other hand, require a lot of floor space. These systems are installed on a fixed path, making them cumbersome and difficult to install. In some facilities, the load limitation and cumbersome nature of conveyors can impede traffic, crowd floor space, and decrease productivity. However, powered conveyor belts and gravity conveyors are perfect for production processes requiring a large volume of material to be moved along a fixed path.
Floor-movers can also pose safety hazards for workers and equipment. For instance, forklifts can turn over when loaded improperly, lifting unbalanced loads, and attempting to lift heavy loads too high. Overturned forklifts can cause significant harm to operators, workers, materials, and equipment. They leave a lot of room for human error, and heavy or unbalanced loads can even fall from a forklift, posing major safety risks for the facility. Conveyors tend to operate at human-height, which can result in worker injury due to clothing or limbs getting caught in the machinery. Some conveyors move materials above head level, especially on flat belts, which can cause materials to fall on workers below.
Overhead Lift Systems
Overhead material handling solutions are a great alternative to on-floor movers like trucks and fixed conveyor systems. They can provide higher productivity and improved safety. Overhead cranes cover a rectangular area, moving a load on three separate axes (two perpendicular and one horizontal). The lifting device is a hoist, which is mounted on a trolley for horizontal movement across a bridge beam connected to one or more horizontal girders supported at either side by end trucks. The end trucks are attached to the girders and move on fixed runways. The horizontal movement of gantry cranes can be manually powered or motorized with air (pneumatic) or electricity. Overhead cranes come in a variety of models, but the most common are bridge cranes and gantry cranes.
Overhead cranes are primarily ideal for use in narrow aisles, crowded facilities with little floor space, or facilities requiring spans in multiple directions. They require far less floor space, which frees movement across the facility and prevents safety issues due to crowding. Freestanding or stand-alone cranes do require floor-mounted support structures, but their footprint is much smaller than the space needed for forklifts and conveyors. Ceiling-mounted systems like overhead bridge cranes and monorails require no floor space at all because they are mounted onto the building’s overhead support structure.
Using overhead cranes can provide multiple safety benefits and improved productivity on the shop floor. These minimize employee labor, provide easy lift solutions for increased efficiency, and reduce injuries caused by improper lifting and falling materials. From small machine shops to giant steel mills, overhead cranes have helped thousands of facilities achieve measured improvements in safety and ergonomics, worker autonomy/personnel reduction, reduced workflow bottlenecks, and increased productivity.