What is Crane: Definition and 137 Discussions

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 to move them horizontally. It is mainly used for lifting heavy things and transporting them to other places. The device uses one or more simple machines to create mechanical advantage and thus move loads beyond the normal capability of a human. Cranes are commonly employed in the transport industry for the loading and unloading of freight, in the construction industry for the movement of materials, and in the manufacturing industry for the assembling of heavy equipment.
The first known crane machine was the shadouf, a water-lifting device that was invented in ancient Mesopotamia (modern Iraq) and then appeared in ancient Egyptian technology. Construction cranes later appeared in ancient Greece, where they were powered by men or animals (such as donkeys), and used for the construction of buildings. Larger cranes were later developed in the Roman Empire, employing the use of human treadwheels, permitting the lifting of heavier weights. In the High Middle Ages, harbour cranes were introduced to load and unload ships and assist with their construction — some were built into stone towers for extra strength and stability. The earliest cranes were constructed from wood, but cast iron, iron and steel took over with the coming of the Industrial Revolution.
For many centuries, power was supplied by the physical exertion of men or animals, although hoists in watermills and windmills could be driven by the harnessed natural power. The first mechanical power was provided by steam engines, the earliest steam crane being introduced in the 18th or 19th century, with many remaining in use well into the late 20th century. Modern cranes usually use internal combustion engines or electric motors and hydraulic systems to provide a much greater lifting capability than was previously possible, although manual cranes are still utilized where the provision of power would be uneconomic.
Cranes exist in an enormous variety of forms, each tailored to a specific use. Sizes range from the smallest jib cranes, used inside workshops, to the tallest tower cranes, used for constructing high buildings. Mini-cranes are also used for constructing high buildings, in order to facilitate constructions by reaching tight spaces. Finally, we can find larger floating cranes, generally used to build oil rigs and salvage sunken ships.
Some lifting machines do not strictly fit the above definition of a crane, but are generally known as cranes, such as stacker cranes and loader cranes.

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  1. A

    Waste Container Handling Crane -- Why are we getting this lift offset?

    I am dealing with a waste container handling crane. Waste container is 12000kg. It is lifted by a grapple by twist locks at each corner. Height of lift is 14m. The contents of the container leads to an offset c of g which cannot be avoided. The containers are to be stacked 6 high. The crane...
  2. Gixer1127

    Lifting a 30m 35te Spud Leg: Crane Weight Calculation

    Hey folks. A quick question. Not homework, very much work related. I've been asked to plan a lifting operation to lift a 30 metre long by 35te (metric tonne) spud leg from horizontal to vertical. The spud leg is essentially a cylinder approximately 2 meters in diameter. It is held at one end on...
  3. salamikorv

    Given force, need to determine what bearing to use for a crane

    Hey! I want to determine what bearings to use for this manual crane and the only thing i know is that it should be able to lift a wieght of 1000kg at max and that the winch should pull 1.24 m of cable/min. Im looking to find the force P to then determine C, and i think P is only the radial force...
  4. B

    Big Robot- Lattice boom crane - calculating maximum stress

    Hello brilliant engineers. How to calculate the bending stress of a lattice boom crane design? It’s clear how to calculate a single chord in a lattice box, at least as a cantilevered tube. However, when placed in a box lattice what is the proper approach? I’m constructing this crane in...
  5. MichaelTam

    How many walls can this battery-powered crane lift before recharging?

    A new, innovative type of crane is battery powered. Its battery has a total energy capacity U , expressed in Joule. Determine how many walls, N of mass m , the crane can lift before the battery has 20% left and needs to be recharged. The walls need to be lifted from /h_1/ to /h_2/ a new...
  6. T

    Sanity check please -- Load cable swinging outward on a rotating crane

    So I know Fcp=-m*w^2*r So from the equation -m*w^2*r=m*g*tan(theta) r = r1+r2 so to rewrite -m*(w^2)*(r1+r2)=m*g*tan(theta) So r1+r2=(m*g*tan(theta))/-m*(w^2) r1=((m*g*tan(theta))/-m*(w^2)) - r2 Am I doing this nearly correct?
  7. T

    Forces acting on a moving crane

    Can someone please help me understand where I am going wrong. I've checked my answer many times and do not understand what I am missing
  8. stphnls

    Crane Lifting a Car -- Find the Work Done

    W= Fd W= 3NX1.20m W= 3.6 J is the work done by the crane W=Fd W=0.6Nx1.20m W=0.72 J is the work done by the car I have no idea how to solve the c, I am thinking at first that the work done by the crane and the car are zero because cos 90 is zero and there are perpendicular to each other. I...
  9. DaveC426913

    Boom Angle of Crane: Is High Extension Necessary?

    These boat hauling cranes seem to extend their booms as high as possible. Much higher than necessary for the max height of the boat lifting rig. Does this accomplish something effort or safety-wise? It's not like a simple torque situation - the force applied is gravity - straight down - not...
  10. FEAnalyst

    Bending of a telescopic crane boom

    Hi, how can one analyze the telescopic boom of a workshop crane in terms of bending ? Of course the worst case is when the boom is fully extended. Should we treat it as a beam with sudden change of cross-section (or otherwise - with sudden change of flexural stiffness) ? I know that there are...
  11. Nero

    Project to design and calculate the hydraulics for a deck crane

    Hi, Iam having a really hard time with this university project. The project is to design and calculate the hydraulics for a deck crane. The crane boom must be lifted with one or more cylinders and you want a boom angle from 0 to 80 degrees. Lifting capacity must be 10 ton on 20 m arm at a boom...
  12. H

    Question about a crane and anchor

    The question is number 25. Where is the tension on X greater. I think it would be A because you have the weight of not only box A but also the anchor pulling down on the rope.
  13. T

    Crane Arm Model using beam theory

    Can a Bernoulli or Timoshenko model be reasonable for a crane arm, on ships? Yes, the arm might have a truss element, yes there is a hydraulic force to lift the arm (or cables). But to some extent, can one model the crane arm as one of a simple beam (either Timoshenko or Bernoulli -- and...
  14. kraub

    What is the required piston force for a crane boom with specific dimensions?

    Hello, I have 2 pics about my case, I has designed crane boom and the problem has occurred when i came this point. As you see the pics, i want to find piston force. Could you help me about this ? (Dimensions=mm )
  15. H

    Problem With a Slewing Bearing Crane

    Dear All Masters I have problem with slewing bearing crane. My subcon made a crane that have a very high platform deck form slewing bearing. They said it is fine and the height is not an issue as it is in lower place. I know the higher the load from slewing bearing, the bigger the force or...
  16. M

    Forces acting on the base of a crane

    I am attempting the work out the forces acting on the base of a crane. I am yet to come across forces at the base of a crane and am confused as to how to work out the reactionary/moment forces. Any help would be greatly appreciated.
  17. H

    Calculate Force Compression of Crane with Hoisting Slink

    Actually it is a simple one, but the point of view of the force acting in pic attach of some people are different. http://www.imagebam.com/image/ef24231032403754 http://www.imagebam.com/image/01c8e71032403724 The adding weight of hoisting slink blue and the pulley is neglected. I think the...
  18. Ridzuan

    RTG crane -- hydraulic motor and linkage design to turn these wheels

    Hi all I would like to ask your professional guide in designing a hydraulic system. I attached a file, showing sketch of the RTG crane wheel structure. Here are the conditions: 1. The red-line is the hydraulic cylinder with "X" as the fix point. 2. The hydraulic cylinder will stroke out from...

    Installing an EOT crane in a factory (ceiling clearance issues)

    PROS AND CONS OF INSTALLING AN EOT CRANES IN A LIMITED SPACE FACTORY. Capacity of the crane is 10 TON, SPAN is 27.6 meter, 4x10 Ton Cranes for 125 meter bay. The space limit in the factory is 10.5 meters. There is a 9 meter steel post at the center of the factory (part of a machine). The crane...
  20. F

    Tower Crane Tie Beam and Anchor Design: Maximum Force and Tension Calculation

    Hello everyone http://imgur.com/kc2kV8V can you please take a look in the tie beam and anchor design from the link above as i could not upload the picture directly. https://ufile.io/6v7l1 https://ufile.io/6v7l1 i want to calculate the maximum force that this anchor can resist before failure ...
  21. M

    Spring Simulation: Visualize and Analyze Moving Systems

    How can I simulate this spring system and see how they move and behave? Thank you.
  22. Ridzuan

    Acceleration resistance in crane design

    Hi everybody Does anyone familiar with this equation? Acceleration resistance, = {(load MOI/mech. efficiency) + (motor MOI) x rpm^2} / {3.65 x 10^5 x acceleration time} = {(kgm^2/ƞ) + (kgm^2) x rpm^2} / {3.65 x 10^5 x second} = final value unit is in kilowatt (kW) It used to calculate the...
  23. Ridzuan

    What is the formula for calculating moment of inertia in RTG crane design?

    Hi guys... appreciate if somebody can help me on the design calculation of the RTG crane... I am stuck to understand the following formulas, used by MITSUBISHI to calculate as follow: 1. Moment of inertia for hoisting = [Lifting weight (kg) x Lifting velocity^2 (m/min)^2] / [π^2 x motor rpm^2]...
  24. WherE mE weeD

    Conservation of energy: Crane raising a mass

    Homework Statement Mechanical crane raises 225kg at a rate of 0.031m/s^2. from a rest to a speed of 0.5m/s over a distance of 4m. Frictional resistance is 112N. m1=225kg a1=0.031m/s^2 u1=0m/s v1=0.5m/s s=4m Fr=112N A. Work input from the motor B. Tension in the lifting cable C. Max power...
  25. Adrian379

    What is the Work Involved in Lifting and Moving a Box with a Crane?

    1. The problem statement, all variables and given/known G=8400N h=35m d=10m g=10m/s^2 A crane elevate a box with G=8400N at h=35. After this, the box is moved horizontal on distance 10m. No friction. Work = ? ps. Sorry for bad English. Homework Equations I think that W=W1 ( work on elevating...
  26. V

    I Solve Boom Crane Position with Lagrangian Equation | Wind Loading Included

    Hi, I am trying to model the position of the suspended mass at the end on a boom crane. This is basically a spherical pendulum, however further complicated by the fact that the mass can be hoisted up and down and also the pivot is connected to an arm (boom) which can be rotated up and down and...
  27. M

    Finding a Second Hand Vector Motor for Warehouse Crane

    The crane that we use in our warehouse is not operational the repair tech said the vector motor is defective. Any recommendation as to where we can find a second hand vector motor?

    How to use partial factors

    Hi everyone my name naresh. I'm doing post graduation, currently working on my project. I've completed all the calculations for it, but i have a small doubut. I've designed a mobile truck loader for which I've taken partial factors 1.35 and 1.5 for dead load and live load respectively. but BS EN...
  29. E

    Conservation of Energy of Mass on Crane

    Homework Statement A mass is suspended from a crane by a cable of length L. The crane and the mass is moving at constant speed V. The crane stops and the mass on the cable swings out. What is the angle that the mass swings? If the angle is 50 degrees and L=6m, what is the initial speed of the...
  30. R

    Moment about a point of a crane

    Homework Statement The towline exerts a force of P = 5.8 kN at the end of the 8-m-long crane boom. If θ = 30∘ determine the placement x of the hook at B so that this force creates a maximum moment about point O. Homework EquationsThe Attempt at a Solution M(max)= 8(5800) = 4.64kN*m My...
  31. R

    Tower Crane Forces: Find the Mass of Counterweight

    Homework Statement Hello, this problem is cracking my mind for days, and I haven't solved it yet :( Crane dimensions: See image Mass of the crane: 10Tons Mass center: G Maximum Load: 4Tons Counterweight: P Weight of the counterweight: ? "A" says: when you have a maximum load (4Tons) at the...
  32. M

    FEA Results Interpretation for a Pin Support

    Greetings to all, I am doing FEA analysis of a jib crane. I am using Autodesk Inventor. The results show that the max Von Mises stress in the support pin is 773 MPa. This value exceeds the yield strength of the Carbon Steel. Does this mean that the Pin will fail under load ?
  33. T

    Removing a crane cylinder, force calculation

    Hi I'm working on a project out in the North Sea on an oil rig, we need to remove a hydraulic cylinder from a crane, I have attached a drawing the red cylinder B needs to be removed. To do this we will move the crane boom to the position shown by the orange lines and rest the end down on the...
  34. S

    Troubleshooting Overhead Crane Gearbox Issues

    I have an overhead crane and we are having some issues with the gearboxes that drive the bridge. The total crane weight is 44250lbs and has a 4 ton capacity. The wheels are 13.5 inches in diameter and have a wheel load of 16500lbs. The gearbox is driven by a 2HP electric motor at 1750rpm...
  35. Le_Anthony

    Work Done by Crane: Calculating Force & Acceleration

    Homework Statement Had a question on a test went something like this; A crane lifts a 425 kg bar 85m above the ground. The crane is lifting it upwards with an acceleration of 1.8 m/s^2. How much work is done by the crane? Homework Equations W=Fd The Attempt at a Solution Solution 1( the one i...
  36. Iqbal94

    Question about a dynamic equation of a crane model

    Hi guys, I have a question on the fundamental dynamic equation as I am not sure if my equation is correct. I am doing an analysis on a portal crane to find its application factor, somehow I couldn't get the desired value for the velocity of each masses as I couldn't find the tension of the...
  37. V

    Finding the WORK done by a crane in lifting a load

    Homework Statement A crane lifts its 500N load to the top of the building from A to B. Distances are shown on the diagram. Calculate how much work is done by the crane Known variables: AB= displacement= 50m AC=horizontal distance=30m BC=vertical distance=40m 2. Homework Equations Work...
  38. N

    Statics: Crane Boom - Why Different Results?

    1. Homework Statement W engine = 500 kg * 9.81 = 4905 N sin t = 3/5 Homework EquationsThe Attempt at a Solution 1. use section AE ΣMa = 0 3/5 * Fcd *2 - 4905 * 3 = 0 F = 12262.5 N 2. use section EB ΣMe = 0 3/5 * Fcd *1 - 4905 * 2 = 0 F = 16350 N why 1 and 2 doesn't result same...
  39. C

    Software design for Truck Crane Loader

    Hi everyone, I am starting the re-design of the PLC software for a preexisting Truck Crane Loader. I will receive the Weight Chart to see what the limits are and I was wondering how to exactly calculate the resulting weight on the Crane. The CRANE is already on place, it has two joints and a...
  40. W

    How much work does a crane and gravity do on a large box?

    Homework Statement [/B]Homework Equations E(p)=mgh W = Fs 3. The Attempt at a Solution The book says the crane does mgh amount of work, while gravity does -mgh. What I don't understand is, for the box to be lifted up, doesn't string tension force have to be bigger than gravity - or else it...
  41. James O'Neill

    Calculating max weight object supports without counterweigh

    In tower cranes counterweights are placed on the counter jib to prevent the crane from falling over. Whereas on mobile cranes the counterweights are placed directly behind the cabin. The crane in itself also acts as some counterweight. My question to you is: How much weight can an object support...
  42. E

    Using Torque to Prevent Cranes from Falling Over

    Hi, I'm looking to find out how torque is used to prevent cranes from falling over. I have to write a report about mechanics in the real world and am trying to decide if this would be a good topic. Is anyone able to explain it to me?
  43. MironeDagains

    Crane pivot force calculation help

    Here's a diagram of what I'm talking about: http://i.imgur.com/irgHuqq.jpg Basically, the only variable altered is the value for x. I tried googling for hours now, have read everything in my book relating to this topic, I still have absolutely no clue how to answer this. I tried studying sites...
  44. S

    What is the Tension in the Tower Crane Cable?

    Homework Statement The beam ABC is1000LBs and its center of mass is given as 6.5ft to right of B. B is a pin joint. A & D are frictionless rollers. Find tension in cable.Homework Equations Call the tension in the cable T. Trig shows us that the left-hand triangle is 45 degrees at ABD and the...
  45. Feodalherren

    What are the forces involved in lifting a 1450-lb load with a hydraulic crane?

    Homework Statement The hydraulic crane is used to lift the 1450-lb load. Determine the force in the hydraulic cylinder AB and the force in links AC and AD when the load is held in the position shown.Homework EquationsThe Attempt at a Solution I don't even know...
  46. X

    Tensions, forces, and moments for an A-Frame crane

    Homework Statement I have to solve for legs AB, CB, and the tension in DB. The weight of the fish net is 200 kg. Homework Equations Sum of moment = 0 Sum of force in x,y,z directions = 0The Attempt at a Solution I have no idea what to do. I've tried using AB and CB as two force members...
  47. D

    MHB Natural frequency of a crane dropping a car

    An electromagnet weighing \(3000\) lb is at rest while holding an automobile of weight \(2000\) lb in a junkyard. The electric current is turned off, and the automobile is dropped. Assuming that the crane and the supporting cable have an equivalent spring constant of \(10000\) lb/in, find the...
  48. N

    Moving retaining pin on 27-ton crane

    I wanted to pose a question here. It's based off a real world situation that I witnessed and was wondering what some people had has opinions (... or good reasoning/math). There is a 27-ton crane which has four outriggers to distribute weight and a rear stabilizer (similar to outrigger in...
  49. R

    Calculating Member Forces of a Crane Lifting a 125kg Motor

    Homework Statement This crane lifts a 125 kg heavey motor. What is the member forces of BF and BD? Use 10 m/s^2 as accleration of gravity. https://dl.dropboxusercontent.com/u/11241083/problemtruss.png Homework Equations F=ma Sum Fx=0 Sum Fy=0 Sum M=0 The Attempt at a...
  50. C

    Can anyone help me check my free body diagram for mobile crane

    Homework Statement https://www.icloud.com/photostream/#AE5oqs3qHTNWQ;B21C49F3-02FB-4EA3-8CE5-D1E2C1FA7C49 Homework Equations The Attempt at a Solution https://www.icloud.com/photostream/#AE5oqs3qHTNWQ;A55D9431-FD6D-4884-9AFC-C4D7C8E39AF1