Most people have heard of cranes but not too many people are familiar with derricks. Both are used to lift and move heavy items, and while they’re similar, they’re also different.
An Overview of Cranes and Derricks
So what’s a good definition of both a crane and a derrick in order to differentiate between the two? A crane is a machine that’s used for lifting/lowering a load, and moving it vertically or horizontally. With a crane, the hoisting mechanism is an integral part of the machine. Cranes can be fixed or mobile, and driven manually or by power. A derrick, on the other hand, is defined as an apparatus that has a mast (or equivalent member) held at the head by guys or braces. It can be with or without a boom, and it’s used with a hoisting mechanism and operating ropes.
Cranes and derricks are both used to lift and move loads, oftentimes to considerable height(s). The differences between them, though, are how they are constructed and how they function.
Most people know what cranes look like, since they see them at construction sites in many cities. Cranes have hoisting mechanisms and pulleys or sheaves. Mobile cranes are mounted on wheels or tracks and can be moved fairly easily and quickly. They can transport material by adjusting the length of their boom. Fixed cranes are temporarily or permanently installed in one fixed location for quite some time– say, for instance, for the construction of a skyscraper in a city.
If you know what cranes generally look like, how might you identify a derrick? Look for a vertical stationary mast that extends from the base, as well as a moveable boom that’s equipped with cables and/or pulleys/sheaves that are connected to the base of the mast.
Cranes are more popular than derricks. When you want to rent a crane for use in New England, contact Astro Crane at 978-429-8666.