Two-blocking occurs when the operator extends the boom on a crane without letting out sufficient slack in the cable. As a result, the stabilizing weight, called the headache ball, will be popped off by the extending boom.
What is double blocking Crane?
A spotter should be available to direct the crane operator where there is the potential for double-blocking. Note: Double-blocking (sometimes known as two-blocking) happens when the hook block or headache ball makes contact with the head sheave(s) preventing further winding up of the hoist.
What does the term two blocking mean?
Filters. Of or pertaining to being prevented from proceeding. From nautical terminology for a ship’s rigging or crane rigging in which two blocks are locked together, stopping the line.
What is a crane load block?
A Load Block is the assembly of hook, swivel, bearing, sheaves, pins and frame and is suspended by hoisting ropes or load chains. It is used to lift and move objects up to a specific lifting capacity.
What are the parts of a crane called?
The Various Functions of Mobile Crane Parts
- The Driving Components. In any mobile crane, one of the common components will be the driving system used to make it mobile. …
- The Operator’s Cabin. The operator’s cabin houses all of the crane’s controls. …
- The Boom. …
- Hoist and Hook. …
- Hydraulic Pump. …
- Outriggers and Counterweights.
6 февр. 2020 г.
What is the hook on a crane called?
A lifting hook is a device for grabbing and lifting loads by means of a device such as a hoist or crane. A lifting hook is usually equipped with a safety latch to prevent the disengagement of the lifting wire rope sling, chain or rope to which the load is attached.
What is limit switch in Crane?
Limit switches are electromechanical devices that regulate everything from household appliances to industrial machinery. For an overhead crane, they provide solid, established points of reference for maintaining efficiency, reliability and safety standards.
What is the purpose of anti two block?
Assure that proper fall protection is utilized by employees working in the basket. Anti two-blocking devices are electrical sensing devices. They are installed on the crane to prevent the “headache ball” from hitting the sheave. If such contact causes the line to break, the man basket can tip or fall.
What is the end of a crane called?
JIB CRANE – A crane design whereby the bridge girder (commonly called the boom) is fixed at one end, allowing the opposite end to cantilever. The fixed end generally is hinged to allow rotation. LIFT – Maximum safe vertical distance through which the hook, magnet, or bucket can move.
What part of the crane is used to lift and lower the load?
Hoist – A mechanical unit that is used for lifting and lowering a load via a hook or lifting attachment.
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)].
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.
What stops the crane from falling over when it lifts something?
Why Don’t Tower Cranes Fall Over? This is mostly down to the concrete base, which is massive and needs to be poured weeks before the crane arrives. The triangulated cross-member structure of the mast gives it more stability and prevents bending. Plus, it’s anchored and bolted to the ground.
What type of materials are lifted by the crane?
Cranes are distinguished from hoists, which can lift objects but that cannot move them sideways. Cranes are also distinguished from conveyors, that lift and move bulk materials, such as grain and coal, in a continuous process.