Hoist – A mechanical unit that is used for lifting and lowering a load via a hook or lifting attachment. Hoist Chain – The load bearing chain in a hoist. Hoist Motion – The motion of a crane which raises and lowers a load. Holding Brake – A brake that automatically prevents movement when there is no power.
How does a crane lift heavy loads?
Cranes combine simple machines to lift extremely heavy objects. In balance-style cranes, the crane’s beam is balanced at a point, called the fulcrum. This allows it to lift heavy objects with a relatively small force. In this way, the crane’s beam acts as a simple lever.
What are the parts of a crane called?
Here are the different parts of a crane.
- Hook. Though all parts of a crane are essential to its ability to lift and move heavy loads, none of it would be possible without the hook. …
- Hoist. The hoist is the part that creates lift in a rigging system. …
- Boom. …
- Jib. …
- Counterweights and Outriggers.
What changes the lifting capacity of a crane?
High wind speeds. High wind speeds affect the capacity of a mobile crane by increasing the side loading on the boom and the load radius and by decreasing the tipping (both forward and backward) capacity. In addition, performing lifts in windy conditions makes it more difficult to handle the load.
What part of the crane is an inclined spar?
Boom (equipment other than tower crane) means an inclined spar, strut, or other long structural member which supports the upper hoisting tackle on a crane or derrick. Typically, the length and vertical angle of the boom can be varied to achieve increased height or height and reach when lifting loads.
How many tons can a crane lift?
Typical lifting capacities are between 12 and 20 metric tons, with the record held by the K10000, made by the Danish firm Krøll Cranes. It can lift up to 120 metric tons at the maximum radius of 100 meters.
Is a crane a movable pulley?
A movable pulley is a pulley that is free to move up and down, and is attached to a ceiling or other object by two lengths of the same rope. Examples of movable pulleys include construction cranes, modern elevators, and some types of weight lifting machines at the gym.
What are the three functions of a crane?
The main purpose of a crane is to lift extremely heavy amounts of weight. A typical crane is equipped with a hoist rope, wire ropes or chains and sheaves.
Modern day cranes are used for:
- Construction Materials.
- Railroad Tracks.
- Shipping Materials/Equipment.
- Scrap Metal.
- Mobile Homes.
5 нояб. 2015 г.
How many types of crane boom are there?
However, a 45-ton truck-mounted telescopic boom crane is ready when it arrives on site and can execute many lifts that same day. Mobile cranes can be further classified by boom type and carrier type. Booms are either conventional lattice truss boom or telescopic boom.
What is the hook on a crane called?
Load Block – The assembly of hook or shackle, swivel, bearing, sheaves, sprockets, pins, and frame suspended by the hoisting rope or load chain. This shall include any appurtenances reeved in the hoisting rope or load chain. … This hoist component is sometimes called load wheel, load sheave, pocket wheel, or chain wheel.
How is Crane SWL calculated?
SWL or WLL are calculated by dividing MBL by a safety factor (SF). An example of this would be a chain that has a MBL of 2000 lbf (8.89 kN) would have a SWL or WLL of 400 lbf (1.78 kN) if a safety factor of 5 (5:1, 5 to 1, or 1/5) is used.
How much can a 40 ton crane lift?
Mobile Lifting Power & Distance
Hydraulic truck cranes vary in lifting power. It’s easy to tell how much a particular hydraulic truck crane can lift just by the name of it: A 40-ton crane can lift 40 tons (80,000 lb or 36,287 kg).
How much can a 50 ton crane lift?
Crawler Crane Information
It has a 50 ton (45.4 t) max lift capacity, 160 ft.
What is the most dangerous factor among crane accidents?
OSHA’s analysis of crane accidents identified the major causes of crane accidents as:
- boom or crane contact with energized power lines (nearly 45% of the cases)
- under the hook lifting device.
- overturned cranes.
- dropped loads.
- boom collapse.
- crushing by the counter weight.
- outrigger use, falls and rigging failures.
What is the major cause of crane accidents?
The main four causes of crane accidents are contact with power lines, overturns, falls, and mechanical failure.
Who can operate a crane?
Operators of most cranes above 2,000 lb. capacity when used in construction will need to be either certified by an accredited crane operator testing organization, such as the National Commission for the Certification of Crane Operators (NCCCO), or qualified through an audited employer program [§ 1926.1427(a)].