The human body is an inimitable creation; a machine that has unparalleled function and an entirety of parts that gives it the ability to perform incredible feats. In a similar fashion, yet naturally not on an equal platform, is a crane. A multi-faceted apparatus, coupled with intricate components, makes for a machine that is heavily based on straightforward laws of physics. Without each part of the crane, it would be unable to complete necessary tasks, just like the human body. Not a single part can lack in structure or functionality, or else the machine will lose its ability to perform necessary actions. If you find yourself wondering, “exactly what is a jib crane?” – jib cranes are a unique type of crane typically used in shipyard docks or warehouses to move materials.
The normal state of function for the human body is known as homeostasis. When a body is in homeostasis, all variables are in check and all parts are functioning properly. For example, temperature and heart rate should be in normal ranges when the body is in homeostasis. In the same way, the main concern for a crane is stability, or its ability to maintain balance to avoid tipping accidents. For this state to occur, all parts must be working in unison in the proper manner. In physics terms, the sum of all moments, or the arrangement of physical components, needs to equal zero to avoid overturning.
Another fundamental for the functioning of a crane is the mechanical advantage. Comparable to the muscles of the human body, mechanical advantage is the concept that a machine, such as a pulley, can multiply the amount of force being applied to it in order to lift heavy materials. Muscles in the body work together to lift a certain amount of weight over a specific distance. Related to the crane, this mechanical advantage is why one man is capable of moving the same amount of weight that it would take a team to move directly.
A jib crane obtains its name from a certain part of the crane known as the “boom.” Similar to the way in which an arm on the human body functions, the boom is a mechanical arm that is used to transport materials. This part is either mounted to a wall at an upwards perpendicular or an acute angle. In the human body, the glenohumeral joint, where the humerus bone of the arm articulates with the glenoid fossa at the end of the collarbone, is what allows the shoulder to have such a large range of movement. Similarly, the crane attachment permits the boom to move in a limited central arc, have lateral movement, or complete the path of a full circle.
The hoist, another significant component, is a unit that is used to lift or lower a load of materials via a hook or other lifting attachment. Like the deltoid muscle slides over the shoulder joint and attaches to the upper arm, a hoist has a rope or chain that wraps around it, giving it the ability to lift a load. Most cranes use a lifting hook to attach to their transportable loads.
Counterweights are an extremely important component in preventing the crane from tipping. In the same way, the body contains proprioceptors, or sensory nerve receptors, that are described as being the “sixth sense.” Situated at the end of the nerves, their job is to relay information to the brain about the body’s position, primarily helping to stabilize and balance the body. Crane counterweights are located at the exterior of the crane around the cab. These stabilize the crane while it transports loads and act as the crane’s proprioceptors.
Just as the core or abdominal muscles of the body support all movement, posture, and breathing, the mast of a crane is the main structure of support. During installation, the steel sections are connected, creating an even stronger support system.
To understand how all of the components of a crane fit together, you have to understand the way in which pulleys function. In the body, a relatable example is the quadriceps muscle, located in the front section of the upper leg. When the tendon of a muscle slides over a bony surface, it acts as a pulley. The knee functions as a simple pulley when the quadriceps muscle is contracted to extend the leg. In a somewhat similar manner, the simple apparatus of a crane pulley reduces the force of the weight of a load and allows the object to be moved with less force than it would require without the pulley. Additionally, the pulley spreads the weight out among the cables and multiplies the force that is used to move the object. A pulley with zero friction will be performing at its optimal function, just as the patella, or kneecap, will function best as a pulley when there is no arthritis, bone fragments, or other inhibitors in that area.
Jib cranes have many of the same parts as other types of cranes, but the few described above are the primary components. Just like the body has countless facets, so do cranes, which is what makes them complex, capable machines.