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Wire rope spooling technology is the technology to prevent wire rope getting snagged when spooled, especially in multiple layers on a drum.
| | This article needs additional citations for verification .(March 2013) |
Wire rope spooling technology is the technology to prevent wire rope getting snagged when spooled, especially in multiple layers on a drum.
Ever since the development of wire rope, comprising multiple wire strands, spooling the wire has presented technical challenges. When wrapped in multiple layers, the upper layers have a tendency to crush the lower layers, while the lower layers have a tendency to pinch upper layers. The rubbing of rope against rope also has a tendency to cause wear. These problems were addressed by Frank L. LeBus Sr., a supplier of drilling equipment to the oilfields of Texas, USA, who in 1938, patented the use of a groove bar on hoisting drums to guide the spooling of rope. Grooved shape steel segments were simply welded or screwed to existing plain steel drums. [1] Ever since then, drum groovings have been widely used to guide the spooling of wire rope onto and off winch drums. Introducing a continuous helical groove onto the drum, like the thread of a screw, provides a way to guide the rope when spooling onto or off a drum. However this has been shown to work effectively only when the rope is wrapped in a single layer. When the rope is wrapped in multiple layers, problems remain. Frank LeBus introduced a grooving pattern that put the groove parallel to the flanges of the drum, except for a single slanted section across the drum face to act as crossover point, moving the rope along by the width of the groove with every revolution.
While the Lebus family business continues to produce this equipment today, their patents have expired. The Lebus name, however, is a registered trademark owned by the Lebus family business so the term "Lebus Drum" specifically refers to products of Lebus International.
The multilayer wire rope spooling system has undergone continuous refinement over the years and adapted for any application where long lengths of steel wire ropes must be wrapped in multiple layers quickly and smoothly. Examples include:
With the parallel groove system, rope wear is considerably reduced in multilayer spooling.
When the first layer has filled the drum, the second layer then travels back across the drum with each wrap of rope sitting precisely along the groove of two wraps of the first layer. With parallel grooving it is possible to calculate the exact forces that the rope imposes on the drum because the spooling is controlled.
Cross winding is reduced to approximately 20% of the circumference of the drum, and 80% remains parallel to the flanges in the inner layer rope groove. This parallel grooving evenly distributes the load between the individual layers and has been shown to increase substantially – by more than 500%, tests have shown – the life of the wire rope. The system has been used to mount ropes up.
In offshore applications, huge lengths of rope are often housed on drums. The anchor winches on Saipem's Semac 1 pipe laying barge, for example, each hold 2,800 metres of 76mm (3 inch) diameter wire rope in 14 layers. Saipem's Castorone, the world's largest pipe laying vessel uses a wire rope that is 3,850m long and 152mm in diameter. It weighs 420t. The rope is pulled by capstan and stored on a massive Rema traction winches that feature the parallel grooving system, with an approximately back tension of 40t on the capstan.
To maximise the benefits of the parallel grooving system, certain operating conditions are required. These include:
Every system should be tailored to the application for which it is used. The groove pattern is engineered to suit the rope's length, diameter and construction type.
In any multi-layer spooling application it is important that when the rope is first installed on the drum, it is done so under tension to avoid any slack on inner layers that can be crushed or nicked against the groove walls by outer layers.
The fleet angle is defined as the largest angle of the rope between the first sheave and the drum flange, relative to the centre line of the drum. With all type of drums, the rope is subject to a fleet angle which impacts on its behaviour and affects lifespan. Fleet angle should be between 0.25° and 1.25°, depending on the rope construction. The fleet angle can be varied by moving the first sheave closer to or further away from the drum. If the sheave is too close to the drum, the fleet angle will be greater than 1.25°; if it is too far away, the fleet angle will be less than 0.25°.
Sometimes it is not possible to achieve the optimum fleet angle. Where there is no space to rig a sheave the requisite distance from the drum, two additional spooling devices are available. One is a fleet angle compensator, which is driven automatically by the rope tension. The other is a level winder that is mechanically driven. Both offer a solution to guide the cable along the drum between flanges, but each has its advantages and disadvantages.
The fleet angle compensator (FAC) is driven by the movement of the wire rope as it goes through the crossover sections of the drum. As the rope winds or unwinds, the FAC shaft automatically oscillates slowly, allowing its sheave to slide back and forth across the shaft to maintain an optimum fleet angle and guide the rope smoothly onto the drum.
Level winders can be hydraulically or electrically driven and computer controlled, or they can be simple mechanical devices. A mechanical level winder comprises a main shaft (the lead screw) with helical screw grooving along which the rope feeder travels. The rope feeder housing includes two vertical roller bars and one horizontal roller, or alternatively a wire rope sheave. The lateral movement of the housing is generated by a chain drive sprocket ratio between drum and lead screw, as shown in the image. The automatic level winder fitted is designed and engineered to be compatible with the grooving on the drum. Alternatively, a sheave can be integrated and installed within the housing frame. In this case, the system can be set up anywhere around the drum. Oceanographic installations that spool rope up to 46 layers have demonstrated that level winders give synchronized and controlled spooling in the harshest, most testing conditions.
Grooving systems for multilayer spooling can be carved onto steel shells that are mounted onto old drums, by either bolting or welding, as an outer sleeve. Called split sleeves, they can be retrofitted onto old drums or mounted on new drums to allow a future change of application.
A pulley is a wheel on an axle or shaft enabling a taut cable or belt passing over the wheel to move and change direction, or transfer power between itself and a shaft. A sheave or pulley wheel is a pulley using an axle supported by a frame or shell (block) to guide a cable or exert force.
A wire is a flexible, round, bar of metal.
A fishing reel is a hand-cranked reel used in angling to wind and stow fishing line, typically mounted onto a fishing rod, but may also be used on compound bows or crossbows to retrieve tethered arrows when bowfishing.
A winch is a mechanical device that is used to pull in or let out or otherwise adjust the tension of a rope or wire rope.
A block and tackle or only tackle is a system of two or more pulleys with a rope or cable threaded between them, usually used to lift heavy loads.
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A mandrel, mandril, or arbor is a tapered tool against which material can be forged, pressed, stretched or shaped, or a flanged or tapered or threaded bar that grips a workpiece to be machined in a lathe. A flanged mandrel is a parallel bar of a specific diameter with an integral flange towards one end, and threaded at the opposite end. Work is gripped between the flange and a nut on the thread. A tapered mandrel has a taper of approximately 0.005 inches per foot and is designed to hold work by being driven into an accurate hole on the work, gripping the work by friction. A threaded mandrel may have a male or female thread, and work which has an opposing thread is screwed onto the mandrel.
A belt is a loop of flexible material used to link two or more rotating shafts mechanically, most often parallel. Belts may be used as a source of motion, to transmit power efficiently or to track relative movement. Belts are looped over pulleys and may have a twist between the pulleys, and the shafts need not be parallel.
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A fly system, or theatrical rigging system, is a system of ropes, pulleys, counterweights and related devices within a theater that enables a stage crew to fly (hoist) quickly, quietly and safely components such as curtains, lights, scenery, stage effects and, sometimes, people. Systems are typically designed to fly components between clear view of the audience and out of view, into the large space, the fly loft, above the stage.
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R/V Roger Revelle is a Thomas G. Thompson-class oceanographic research ship operated by Scripps Institution of Oceanography under charter agreement with Office of Naval Research as part of the University-National Oceanographic Laboratory System (UNOLS) fleet. The ship is named after Roger Randall Dougan Revelle, who was essential to the incorporation of Scripps into the University of California San Diego.
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A fitting or adapter is used in pipe systems to connect sections of pipe or tube, adapt to different sizes or shapes, and for other purposes such as regulating fluid flow. These fittings are used in plumbing to manipulate the conveyance of fluids such as water for potatory, irrigational, sanitary, and refrigerative purposes, gas, petroleum, liquid waste, or any other liquid or gaseous substances required in domestic or commercial environments, within a system of pipes or tubes, connected by various methods, as dictated by the material of which these are made, the material being conveyed, and the particular environmental context in which they will be used, such as soldering, mortaring, caulking, Plastic welding, welding, friction fittings, threaded fittings, and compression fittings.
A winding machine or winder is a machine for wrapping string, twine, cord, thread, yarn, rope, wire, ribbon, tape, etc. onto a spool, bobbin, reel, etc.
A tripod head is the part of a tripod system that attaches the supported device to the tripod legs, and allows the orientation of the device to be manipulated or locked down. Modular or stand-alone tripod heads can be used on a wide range of tripods, allowing the user to choose which type of head best suits their needs. Integrated heads are built directly onto the tripod legs, reducing the cost of the tripod system.
Rigging is both a noun, the equipment, and verb, the action of designing and installing the equipment, in the preparation to move objects. A team of riggers design and install the lifting or rolling equipment needed to raise, roll, slide or lift objects such as heavy machinery, structural components, building materials, or large-scale fixtures with a crane, hoist or block and tackle.
A hydraulic jigger is a hydraulically-powered mechanical winch.
In electrical engineering, coil winding is the manufacture of electromagnetic coils. Coils are used as components of circuits, and to provide the magnetic field of motors, transformers, and generators, and in the manufacture of loudspeakers and microphones. The shape and dimensions of a winding are designed to fulfill the particular purpose. Parameters such as inductance, Q factor, insulation strength, and strength of the desired magnetic field greatly influence the design of coil windings. Coil winding can be structured into several groups regarding the type and geometry of the wound coil. Mass production of electromagnetic coils relies on automated machinery.