Chapter 3: Hoisting and Material Handling Equipment — The Use of Cranes and Material Handling Tools
Hoisting and moving heavy materials from one point to another around a job site requires the use of specialized machinery. In some cases, a crew may need to suspend the materials when building large-scale projects such as industrial buildings, dams or skyscrapers. The invention of cranes made material handling on a large scale easier for work crews.
Hard-to-reach locations where trucks and other construction vehicles cannot traverse may need steel, heavy equipment and supplies. Engineers developed these pieces of heavy equipment to provide stability, distribute weight and offer safety when handling heavy loads at shorter distances. Crews often affix these simple machines to a platform, either mobile or static, to offer a mechanical advantage over other types of man-powered, pulley-based or motor-driven hoisting methods. Cranes represent essential components to construction, and crews primarily use them for the heaviest of lifting tasks.
By employing hoisting and other material handling machines at your work site, you can avoid the costly loading, hauling and unloading of materials from multiple pieces of heavy equipment. Hoisting equipment can also include jacks, winches and chain hoists.
What Are Hoists and When Do Crews Use Them?
Hoists lift and lower by use of a chain, cable, wire or rope. In this sense, cranes are also a type of hoist because they employ wires, cables or ropes for moving objects from one place to another. For small applications, hoists in conjunction with pulleys can be operated by hand.
When elbow grease and muscle isn’t enough because of the weight of the object being hoisted, electric, pneumatic or hydraulic-driven hoists may be used. Electric hoists are easy to operate and offer more flexibility, while chain hoists are used for simple lift and lower operations.
Materials aren’t the only vital pieces of a construction project that may need hoisting. Workers may need to be hoisted through the use of temporary elevator systems, or lifts, during the construction of larger-scale building projects.
It is important to safely secure workers, making them capable of getting to hard-to-reach or elevated areas on a project. Workers can use boom lifts, or boom hoists, to access hard-to-reach places. They are common in construction but also in maintenance operations such as working on utility poles.
How Forklifts and Conveyors Fit In
On the smaller scale, forklifts and conveyor systems also provide similar functions in terms of handling materials. Conveyor systems operate as a means to transport large quantities of a material such as waste, supplies or equipment over a relatively short distance. Forklifts move small loads over short distances and provide flexibility and maneuverability that conveyors do not.
Here’s a look at some of the most common hoisting and material handling devices, including different types of cranes and conveyor systems you may see on a job site.
1. Mobile Cranes: Easy to Relocate on Short-Term Projects
Mobile cranes provide easy relocation at different areas of a job site. Wheels or tracks house most mobile cranes, and they offer adequate weight distribution and maneuverability over rough terrain. However, the design of mobile cranes also presents some safety issues:
- They are not capable of lifting loads as heavy as some other types of cranes
- They can be prone to overloading because of a lack of safety features
Mobile cranes, however, are the best choice for short-term projects and maximum mobility throughout a varying job site. Their mobility gives them an advantage and can save on the costs of setting up and relocating a more static crane.
2. Derrick Cranes: Lifting up to 200 Tons
These unique cranes feature a mast, a boom and a wheel-driven rotation. When constructing very large, high structures such as multiple-level apartment complexes, hospitals or other industrial buildings, derrick cranes may be employed. As common with most industrial construction equipment, to operate a derrick crane, you need to be certified based on OSHA’s rules.
These cranes do offer the ability to lift up to 200 tons and have full 360-degree rotation features. They operate under diesel power and electric power. For longer-term projects, derrick cranes are more common than mobile cranes, which are employed on a short-term basis.
3. Tower Cranes: A Bigger Version of the Derrick Crane
Tower cranes are similar to derrick cranes, but they’re mounted on a large steel tower for maximum height and stability. Crews employ them for the construction of skyscrapers and large high-rise buildings. Unlike mobile cranes, tower cranes get deployed for large, long-term projects and are considered some of the safest cranes in use.
Like the derrick crane, they offer incredible capacity for heavy loads and rotation from a single bull-wheel base. A tower crane’s load capability depends on the height, reach, lifting power and counterweights — and the placement of the load in relation to the jib.
4. Conveyors: Moving Materials From One Place to Another
While they may get overlooked because of their simplicity, conveyors fulfill essential functions for heavy equipment utilized at building sites. They offer incredible versatility in transporting large quantities or heavy materials from one area to another.
They can convey material in a variety of directions, either vertically, horizontally or on an incline, using a consecutive chain belt to push materials through quickly. In most mining operations, and for the movement of concrete, crews employ conveyors. Advantages to their use include:
- Saving time
- Increasing overall output
- Running continuously
Belt conveyors operate using a rubber belt that runs over a series of drums or pulleys. These types of conveyors handle all kinds of materials, both wet and dry, and can convey thousands of tons of material per hour over long distances. They are also lightweight and have speed control functions to increase or decrease output.
For more grain-sized materials, crews may use screw conveyor systems instead. Screw conveyors cost less, but do not handle the large quantities belt conveyors docost less. They operate by a motor that drives a screw or helix over a bearing from one end. Material enters one side and pushes through the conveyor before being carried to the other end by the rotation of the screw.
You may also see a bucket conveyor, another common type. Through a series of buckets moving vertically or on an incline, material rises from a lower level to a higher level. Also referred to as bucket elevators, these machines are very common in the coal industry to transport coal from one point to another.
5. Forklifts: Moving Heavy Materials Back and Forth
Forklifts might not come to mind when you think of a piece of heavy equipment for construction work, but these little workhorses offer versatility and maneuverability in lifting and moving heavy materials or supplies from one place to another. Depending on the application, forklifts have different load capacities, mostly between one and five tons. However, some may be designed for larger load capacities.