Your jobsite is complex and if it is your responsibility to get the right crane for the job, you need to understand all the variables that go into selecting the right crane for the job. There are many factors to consider for your crane rental:
- Site characteristics
- Environmental impact
Whatever your heavy lifting needs are — whether your construction site is in the middle of a dense urban environment, working inside a factory or plant, or even at port — there are cranes to help you safely lift and place in any environment.
This article will break down cranes, their parts and the various types available for your job
What Are Cranes?
A crane is a type of machine — generally equipped with a hoist rope, wire ropes or chains, and sheaves — that can be used both to lift and lower materials and move them horizontally. It’s mainly used for lifting heavy objects and transporting them to other places.
Cranes have a long history, going back to ancient times. In the Middle Ages, for example, crane-like devices were used to build the roofs of European cathedrals. They were transformed by the industrial revolution to resemble their current forms.
Cranes are used in industries like shipbuilding, construction, and manufacturing. They even have applications outside of these industries, as some famous shots in movies were achieved by means of a camera attached to a crane or jib arm.
Cranes are usually powered by internal combustion engines, electric motors, or hydraulic engines, making them far more capable of lifting heavy loads than earlier versions were.
Some cranes are still manual, however, going back to the earliest days of using balance and ergonomics to lift heavy materials much higher and more easily than human effort could alone.
There are different kinds of cranes, but they all have similar components:
- Rotex gear
The base gives the crane stability. The Rotex gear allows for movement of the boom — the long, steel arm of the crane that you typically see moving. The boom can be extended with a jib, a lattice-like steel structure. The jib allows for further extension, if necessary.
Counterweights provide additional stability to help keep the crane stable, both at rest and while lifting.
Within these general parameters, there are many kinds of cranes, and innovations are still being made. The broad categories are:
All Terrain Cranes
All terrain cranes, as the name implies, are sturdy and versatile. They have a lifting capacity of between 100 and 900 tons.
All terrain cranes are suited for a wide range of jobsites including commercial construction sites, power plants, industrial factories, or telecommunications jobs. They often feature impressive load-bearing capacities as well as extension capabilities. They can be transported down all kinds of roads, including public ones, making them an accessible option for most sites.
All terrain cranes have been used in the most remote construction sites for jobs like erecting wind turbines and lifting heavy concrete segments.
Rough Terrain Cranes
Rough terrain cranes are a bit of a catch-all category. Generally, they are a multi-purpose-use crane that is uniquely designed to access and perform work in confined lifting areas, can travel and work on un-improved work sites and is operated and driven from only one cab. Over-sized tires, a short wheelbase, and crab steering all contribute to overall maneuverability.”
They have a lifting capacity of 18 to 165 tons. They are typically mounted on very sturdy, heavy-duty, four-wheel-drive tires and are designed with difficult-to-reach locations in mind. They have enhanced stability and heavy-duty lift capacities.
You can see rough terrain cranes being used in places like:
- Power stations
- Petrochemical plants
- Commercial construction sites
- Large-scale infrastructure projects like bridges
They’re powered by a single engine. Rough terrain cranes are stabilized by outriggers when working. Outriggers are additional beams that extend from the lower works of a crane to increase its stability.
Unlike rough terrain cranes, which are usually mounted on outriggers, crawler cranes can move around your site and perform various lifting tasks on site.
Crawler cranes are large and may need to be constructed themselves by other assist cranes. They have very high lift capacities ranging from 80 to 3,300 tons. Like Rough Terrain cranes, they’re often used in places such as:
- Floating structures
- Mountainous regions
- Anywhere that’s hard to access — even sometimes for piling and drilling
Crawler cranes have been used to construct wind turbines and nuclear power stations as well.
Crawler cranes are very adaptable, and variable boom systems can extend their range of uses. They’re often used in difficult, off-road conditions.
Telescopic crawlers, for example, have even been used to carry out tunneling work on the Swiss Gornergrat railway, involving navigating a very difficult route with gravelly turf, sudden bends in the road, and enormous gradients.
Tower cranes can lift from 100 to 1,000 tons and need to be constructed themselves at the sites where they’re employed. There are many styles of tower cranes, including:
- Hammerhead cranes
- Luffing jib tower cranes, whose jibs can be raised and lowered
- Derrick cranes, which have very small footprints
- Self-erecting tower cranes, which have a smaller lifting capacity like lifting materials to a roof
- Self-supporting tower cranes, anchored with concrete bases — most useful when ground conditions are poor
Tower cranes have a distinctive look. They’re the cranes you see against the skyline, hoisting large concrete blocks and steel to build high towers.
Hammerhead cranes, originally a German invention, were used by the British to build warships from 1904 to 1911 and are also a fixture of other naval yards around the world.
Tower cranes work by balance. They have:
- A base, bolted to a large concrete pad supporting the crane
- A mast, or tower, which gives it its height
- A slewing unit, which allows the crane to rotate
- Stay rods and a support frame
On top of the slewing unit are a jib, a horizontal machinery arm, and the operator’s cab. Tower cranes allow cities to be built. Tower crane operators are capable of seeing most of the lifting operations from the cab, although support crew is required at the ground level, both for overseeing the loading of the crane and for issuing signals and guidance to the operator.
Common examples of boom trucks are the phone and gas company trucks you see with folded arms on their roofs, cherry picker style. In the commercial construction business, boom trucks are used to lift and place lighter loads using an industrial hook rather than a bucket or other extension.
In addition to being versatile and reliable, boom trucks are designed to provide important functions that, when combined, are extremely useful for most daily construction sites.
Boom trucks look like cherry pickers because — well, they are. The cherry picker was, in fact, originally invented for fruit picking. Its inventor, Jay M. Eitel, built a maneuverable, telescoping device mounted on a truck chassis with a single-lever control.
The Bell Telephone Company would eventually take his company over and add the device to the tops of its vans, so work could be done on telephone cables from a simple truck base.
Carry decks are small, four-wheeled machines with a rated lift capacity of 4 to 25 tons. These smaller cranes are primarily used in industrial plants. They have excellent turning capacity, with a 360-degree rotating boom at their center.
Carry decks are very versatile and handy in awkward or narrow spaces. They also have applications in bridge building and other general infrastructure construction.
A relatively recent American invention, carry decks can hoist a load in tight spaces. They’re usually equipped with hydraulic controls and are capable of precise operations.
Hydraulic Truck Cranes
Hydraulic truck cranes are, simply, cranes attached to trucks, with lift capacities ranging from 40 to 140 tons. They are similar to All Terrain cranes but with only one steer axl. Truck-mounted cranes are mostly used for:
- Transporting heavy loads, like specialized vehicles (such as boats, yachts, and motor cruisers)
- Cargo handling
- Electric line maintenance
Hydraulic truck cranes, invented in 1947, are street legal and can be operated by one- or two-person crews. They tend to be used for lighter loads and are easy to maintain, on account of having fewer moving parts. Hydraulic truck cranes, like other similar cranes, consist of:
- A two-gear pump — a pump that helps to pressurize the hydraulic system
- Outriggers — retractable beams that increase the crane’s stability in a stationary position
- Counterweights — the large, heavy weights used for stabilizing the crane while handling the load
- Rotex gear — the large gear located underneath the operator’s cab and operated with a joystick-type controller, allowing the controller to move the boom left and right.
The crane sits atop a truck, making it easy to position at a site. The use of hydraulics — meaning the use of pumps and liquids to operate against counterbalances — makes it easy to control as well as accurate. Hydraulic systems also provide constant force and torque, making them more reliable than pneumatic systems.
Hydraulic systems also tend to be quieter — a consideration if you’re working in busy or urban areas.
Renting the Right Crane
A lot goes into finding the right crane to make your site safe and efficient. When it comes to crane rentals, it’s critical to have a knowledgeable guide to help you. Maxim Crane rents cranes from the best manufacturers in the business, from the U.S. to overseas, including:
- Liebherr, winner of the ESTA award, Europe’s most important award in the area of cranes and transport
- Broderson, one of many post-war “Greatest Generation” successes that helped turn America into an economic superpower
- Potain, which has led the world in tower crane and self-erecting crane production since its inception in La Clayette, France, in 1928
- Terex, winner of the People’s Choice Award at the Swedish Steel Prize awards
- Link-Belt, winner of two environmental awards from the Specialized Carriers & Rigging Association for its commitment to continuous improvement in environmental and manufacturing techniques
Maxim Cranes employs one of the largest experienced and qualified safety staffs in the industry. All our staff members have one goal in mind: to complete your job as efficiently and safely as possible. Maxim can help you at every stage of your job, from inception to completion.
Maxim offers multiple levels of pre-planning, including:
- Engineering services
- Project management
- Site safety planning including:
- Pre-lift job walks
- Daily risk assessment meetings
- Job hazard analysis
- Audits performed by all levels of management
If you’re looking to rent a crane, get in touch to talk to one of our many informed sales representatives. We’d love to steer you to the right choice for your needs and budget.