What is Crane? Parts of Crane, Functions & Diagram

What is Crane?

As we all know, it is challenging to handle and ship heavy loads during building construction. To solve this problem, the innovation of the crane helps the most. It is a machine that lifts a heavy load at a specific height to reduce human effort and extra time. It can be fixed or mobile, depending on the type of the project. As the name suggests, fixed cranes are mounted in a single place, whereas mobile cranes can move from one place to another. These are mounted on the movable platform that may be either motorized or manual. Mobile cranes come with a telescopic boom and extend as per requirement.

What is Tower Crane?

A Tower crane is a metallic Struss-type structure that rises more than 50 feet in the air to lift a heavy load. These tower cranes help workers on the construction site to lift the steel, concrete, generators, and more on the top of the building. It reduces human effort and reduces time.

Parts of Crane Diagram

Parts of Tower Crane, Functions & Diagram

Crane Parts Names

  • Hook
  • Wire Rope & Shaves
  • Boom
  • Jib
  • Tower/Mast
  • Counterweights
  • Turntable
  • Counter Jib
  • Hoist
  • Tower Peak/Apex
  • Outriggers
  • Wheels & Tracks
  • Cabin

Tower Crane Parts and Functions


The hook is the main lifting point of the crane. All crane structure gives support while lifting a load, but the only hook gets in contact with the lifting load.

On the construction site, if you need to move the load from one location to other, we use the hook to clamp the load and lift it by crane.

As we know, we use a crane to lift heavy loads. So, it is necessary to use high-strength material for the hook. It should be durable and robust to sustain the high load and jerk load.

The design and shape of the hook also matter. If hook design & shape is as per the standard, then there are fewer chances of failure due to high load. So, it is necessary to consider the design factors while designing a hook. Out of all crane parts, hook design is critical and important.

Wire Rope and Sheaves

Wire ropes of the crane are made from steel by combining multiple ropes to make one wire rope. Combining multiple ropes increases the strength of the wire rope. Its size is noted as 6 x 19 strand or 6 x 7 strand.

It is the only medium to connect with the hook. It should have enough strength to sustain the lifting load and jerk load.

The shave is the pulley with grooves in it. It is present at the end of the boom. Wore rope passes through the shave and connects to the hook. The shave increases the load-carrying capacity of the wire rope.

Wire rope is passed through the shave multiple time to increase the weight distribution. The material of the shave plays an important role when selecting it.


Boom is the fixed outreach of the crane. The boom is the long and robust part of the crane that can see it from a long distance. It can be the Struss structure with less weight.

Boom starts from the operator’s cabin and ends at the shave from which wire rope passes. It holds the shave, wire rope, and hook. Boom strength is the main parameter when designing a crane.

From the hook, the load transfers to the boom via wire rope. Due to the long length of the boom, it is necessary to select higher strength material.

There are two types of the boom.

lattice boom- It is made by connecting structural member welding. In short, it is a Struss structure. It increases the strength of the boom and reduces weight.

Hydraulic Boom- It is a hollow structure in which multiple cylindrical shape members are inside with decreasing cross-section. In short, it is a telescopic boom that increases its length as per requirement.

With this outreach, we can cover the area coming under the outreach. But if you need to cover more distance than the boom outreach, how do you do it?


Answering the above question, jib plays an important role in that case. Its function is to extend the outreach of the crane to lift the load.

In the telescopic, we can see the extendable jib to achieve a different outreach per requirement.


It is a central part of the crane to hold the boom, counterweight, cabin, counter jib, and other accessories. It has Struss members welded to make a mast. We can adjust its length as per the requirement.


Crane holds three types of weight.

  • Lifting weight
  • Counterweight
  • Self-weight

A boom has a long length. When the crane lifts the load, it is necessary to balance the load to work the crane properly. So, cranes are using counterweight to balance the lifting load. Without a counterweight, it is not possible to lift the load. Otherwise, the crane gets damaged.

The counterweight is always on the opposite side of the lifting load. As per the lifting load, the counterweight adjust its counter length to balance the load.

These counterweights are removable. As per the site location, we can move them and install them on the crane. Generally, the material of the counterweight is iron.


The function of the turntable is to allow the tower crane to rotate at 360 degrees in the field. It is the assembly of the sleeve ring bearing present on the top side of the tower crane.

Counter Jib

It is a portion of the jib present at the counterweight side of the crane. It is of short length and has a counterweight to balance the crane.


The function of the hoist is to lift the load with the help of the wire rope and hook. It is lifting equipment mounted on the crane, which wounds thousands of meters of wire rope.

So from the various high depth, we can lift the load and transport it to any point of the job site. Without the hoist, the crane is the only structure that is stationary. The hoist gives the ability to lift the load and transport it to any location in the field.

Tower Peak/Apex

Tower Peak/Apex is the extended portion of the mast to support counter jib and jib with the help of the rear peak and front peak. It gives support to the wire rope to pass from the hoist to the front hook assembly to the loft load.


Outriggers are an additional safety to the crane while transporting any material on the site. It extends from the bottom of the crane and shifts the bottom wheels to stabilize the crane.

Outriggers, counterweight, and lifting load help the crane safely transport the heavy load on the site. There is a need for extra safety as so many peoples are working on the site.

Wheels and Tracks

Wheels and track are the two options available for the crane. In the wheel crane, we can move it over the site as per the requirement. It is suitable for bumpy surface conditions. Its speed is higher than the track crane.

Track crane gives higher safety than wheel cranes. For the track crane, we require a smooth surface for easy operation. Due to its high security, it is the first choice in most fields.


Cabin present on the mast where counter jib, mast top, and boom meets. It is for the operator to sit comfortably to operate the crane.

The cabin is made of strong material with all safety precautions and is available to the basic requirement of the person. It has glass on the front to see the site and get better visibility.

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