Becket – A wedge socket type wire rope end termination. Block – A term applied to a wire rope sheave (pulley) enclosed inside plates and fitted with some attachment such as a hook or shackle. Braided wire rope – a wire rope formed by plaiting component wire ropes.
Thereof, what is Reeving on a crane?
A wire rope reeving system is essentially a rope system in which wire rope travels around drums and sheaves, or pulleys, for the purpose of hoisting or hauling. Wire rope is designed to cope with hostile environments; each individual wire is coated with zinc, or galvanized.
Beside above, what is Becket load? BECKET LOAD: The load in any fall of rope in a multiple fall tackle or purchase. It equals the total load being lifted divided by the number of falls supporting the load.
Likewise, people ask, what is two blocking a crane?
Two-blocking is defined as, ” the condition in which the lower load block (or hook assembly) comes in contact with the upper load block (or boom point sheave assembly), seriously interfering with safe operation of the crane.” When two-blocking occurs, life threatening forces can be applied to the hoist or hook
What is a hoist line?
A hoist is a device used for lifting or lowering a load by means of a drum or lift-wheel around which rope or chain wraps. The most familiar form is an elevator, the car of which is raised and lowered by a hoist mechanism. Most hoists couple to their loads using a lifting hook.
19 Related Question Answers Found
What is load radius of Crane?
The ‘ft. ‘ indicator on the left axis represents the radius, the distance from the center pin to the center of the load. EXAMPLE: You need to lift a load of 15 tons (30,000 pounds) a distance of 25 feet. The distance is measured from the center pin of the crane to the center of the load.
What are the legs on a crane called?
Shear legs, also known as sheers, shears, or sheer legs, are a form of two-legged lifting device. Shear legs may be permanent, formed of a solid A-frame and supports, as commonly seen on land and the floating sheerleg, or temporary, as aboard a vessel lacking a fixed crane or derrick.
What is a live boom crane?
Free Fall Generally Prohibited Some older cranes are designed with a “live boom,” where the rate of lowering the boom can only be controlled by a brake. Failure of the brake can lead to free fall of the boom and a risk of death or serious injury to workers near the crane.
What is a hook block?
“A hook block is an assembly to which the hook of a hoist or crane is attached; it typically consists of a steel enclosure housing a number of sheaves or pulleys that carry the ropes or chains that facilitate the lifting of a load.
What is rigging in Crane terminology?
Rigging is both a noun, the equipment, and verb, the action of designing and installing the equipment, in the preparation to move objects. Rigging is the equipment such as wire rope, turnbuckles, clevis, jacks used with cranes and other lifting equipment in material handling and structure relocation.
What is the hook on a crane called?
HOOK APPROACH – The minimum horizontal distance between the center of the runway rail and the hook. JIB CRANE – A crane design whereby the bridge girder (commonly called the boom) is fixed at one end, allowing the opposite end to cantilever.
What is the purpose of anti two block?
An anti-two-block system is used to prevent or warn the operator of a two-block condition on a crane. Two-blocking is the dangerous condition where the lower hook block is raised until it contacts any part of the boom tip hardware.
What are the 5 principal parts of Category 1 and Category 4 cranes?
Crane Components The principal parts of most Category 1 and Category 4 cranes are: the boom, machinery house, roller path or rotate bearing, supporting structure, and travel system.
How do I stop two blocks?
When two-blocking could occur without movement of the load hoist, clearly mark the cable (so that it can easily be seen by the operator) at a point that will give the operator sufficient time to stop the hoist to prevent two-blocking, and use a spotter when extending the boom.
What is the most common cause of crane related fatalities?
The most common cause of fatalities is workers or bystanders who are struck by an object that falls from the cranes. Other causes include being run over by a crane, falling from a crane, and electrocution.
What is limit switch in Crane?
A crane limit switch, or crane power limit switch, is a safety device designed to prevent the over-travel of a crane hoist. Crane limit switch AFTER. Crane limit switch BEFORE. The limit switch is operated by contact with the crane hook block. When activated, the limit switch interrupts power to the lift motor.
What is a load moment indicator?
OSHA Cranes & Derricks in Construction Definitions. Load Moment (or Rated Capacity) Indicator means a system which aids the equipment operator by sensing (directly or indirectly) the overturning moment on the equipment, i.e., load multiplied by radius.
Which types of limit switches are used in cranes and hoists?
Rotary FG50, 100 Limit Switch Rotary geared type limit switches are suitable for use reversing drives such as hoists, winches, rolling mills and various other mechanisms used such used in steel plants such as coke oven and feeding machinery.
What is a Reeve factor?
Max load = SWL (of sling) x angle factor x reeve factor For example: The SWL of each leg of a two-legged sling is 8 tonnes, the angle between the two sling legs is 60 degrees and they are reeved around a square load. This means a factor of 1.73 for the angle and another factor of 0.5 for the reeve.
How is crane load capacity calculated?
The base formula for the Crane Capacity Index is: * For each main boom length at each radius the “Lifting height*Capacity” is calculated. At one radius the value of “Lifting height*Capacity” varies with different main boom lengths. At each radius the maximum value of “Lifting height*Capacity” is chosen.
How are winches rated?
Winches are rated based on pulling against a static load and with only one layer of wire rope wrapped around the drum. But when a winch is in use and rope is pulled in and layered on the drum, the winch’s pulling power drops. A winch has its greatest pulling power on the first 2 layers of rope.
How do you calculate a winch line pull?
The equation for this is F=T/X, where F is the weight of the load (or line pull), T is the output torque and X is the distance from the center axis of the winch or similar device perpendicular to the point where the rope exits the winch or similar device.
When the number of layers of rope on a drum increases the?
For each layer of wire rope on the hoist drum, the effective diameter of the drum increases by approximately twice the wire rope diameter. For example, if the wire rope diameter is 3/4″, the effective drum diameter will increase by 1 1/2″ for each layer on the drum.
What is a block on a crane?
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.