Wire Rope Clips - A temporary eye splice may be put in wire by using wire rope clips. There correct and incorrect ways of using these clips. The U-bolt always goes over the bitter end and the roddle on the standing part. Space the clips at a distance equal to six times the diameter of the wire. After the rope is under strain, tighten the clips again. On operating ropes, tighten the clips every couple hours, and inspect the rope at points where they occur. Look at the clip farthest from the eye, because vibration and whipping are dampened there, and fatigue breaks are likely to happen.
To get maximum strength in the temporary eye splice, use the correct size and number of wire clips. The size is stamped on the roddle between the two holes.
Showing posts with label WIRE. Show all posts
Showing posts with label WIRE. Show all posts
Sunday, November 18, 2007
SPLICING WIRE ROPE
Splicing Wire Rope - Wire rope is usually six-stranded with a hemp core. Work the strands separately, but in some splices, pairs may be worked. This kind work calls for special tools and some degree of skill with lots of practice. If you know somebody who has done these splices have them help the first couple of times. When splicing wire, always insert the marlinspike against the lay, but make sure that you do not shove it through the core. In tucking the strands of a splice, open out the lay of the rope and leave the spike in, holding the strands apart until the tuck has been made.
Liverpool Eye Splice The Liverpool splice is one of the most common and the easiest of the eye splices to put. Never use it in a wire that when loaded, is free to spin, because it will pullout.
To find the distance to which the strands should be unlaid, multiply the diameter of the wire by 36 inches. Find and measure off that distance, and put a seizing on. Another seizing should be put on just below the point where the first tuck is to be made. Next, cut the end seizings, and unlay the strand, and whip the ends of each strand tightly with several turns of sail twine or tape. Cut out the core, form the eye, and put it in a vise, with the unlaid strands on your left. Stretch out the standing part of the wire, and you are ready to go to work.
The first strand of the splice goes under three strands, the second under two, and the third under one. They all enter at the same point but come out at different places.
The next tucks are made by wrapping each strand back around and under the strand it is already under. To avoid kinking the strands on the last tucks, insert the spike and run it up the wire. Follow the spike up with the strand, shove it under the spike, and pull taut. Keeping a strain on the strand, work the spike and strand back around and down together. Hold the strand there and work the spike back up the wire. Follow up with the strand, and take the last tuck. Work that strand back down and hold it there. Pull out the spike, run it back up until the strands of the standing wire bind the working strand in place. Make the second and third tucks with the remaining strands in the same way. A locking tuck may be taken after completing the third round of tucks to decrease the possibility of the splice working out. For this tuck, take every other strand and pass each of these over two strands, and tuck under the next strand. Each of these strands goes over the next working strand as well as the two strands of the standing part and locks the splice in place.
Liverpool Eye Splice The Liverpool splice is one of the most common and the easiest of the eye splices to put. Never use it in a wire that when loaded, is free to spin, because it will pullout.
To find the distance to which the strands should be unlaid, multiply the diameter of the wire by 36 inches. Find and measure off that distance, and put a seizing on. Another seizing should be put on just below the point where the first tuck is to be made. Next, cut the end seizings, and unlay the strand, and whip the ends of each strand tightly with several turns of sail twine or tape. Cut out the core, form the eye, and put it in a vise, with the unlaid strands on your left. Stretch out the standing part of the wire, and you are ready to go to work.
The first strand of the splice goes under three strands, the second under two, and the third under one. They all enter at the same point but come out at different places.
The next tucks are made by wrapping each strand back around and under the strand it is already under. To avoid kinking the strands on the last tucks, insert the spike and run it up the wire. Follow the spike up with the strand, shove it under the spike, and pull taut. Keeping a strain on the strand, work the spike and strand back around and down together. Hold the strand there and work the spike back up the wire. Follow up with the strand, and take the last tuck. Work that strand back down and hold it there. Pull out the spike, run it back up until the strands of the standing wire bind the working strand in place. Make the second and third tucks with the remaining strands in the same way. A locking tuck may be taken after completing the third round of tucks to decrease the possibility of the splice working out. For this tuck, take every other strand and pass each of these over two strands, and tuck under the next strand. Each of these strands goes over the next working strand as well as the two strands of the standing part and locks the splice in place.
Friday, November 16, 2007
HANDLING WIRE ROPE
Long lengths of wire rope usually are mounted on reels. Never attempt to unreel wire rope from a stationary reel. Mount the reel on a pipe or rod supported by two uprights. This method allows the reel to turn as the wire rope is pulled. Unreeling presents no problem, but to spool the wire rope back onto the reel may give you some trouble unless you remember that it tends to roll in the opposite direction from the lay. For example, a right-lay wire rope tends to roll to the left. A rightlay wire rope should be started at the left and worked toward the right when spooling over the top of the reel. When spooling under the reel, start at the right and work toward the left. Left-lay wire rope is handled just the opposite.
If wire rope is being run off one reel to a winch drum or another reel, it should be run from top to top or from bottom to bottom.
Short lengths of wire rope may be made up in coils and stopped off tightly for stowage. When uncoiling wire rope, stand the coil on edge and roll it along the deck, uncoiling as you go, as in.
If a wire rope becomes kinked, never try to get the kink out by putting a strain on either part. As soon as a kink is noticed, uncross the ends pushing them apart. This method reverses the process that started the kink. Turn the bent portion over and place it on your knee or some firm object and push downward until the kink straightens out somewhat. Then lay it on a flat surface and pound it smooth with a wooden mallet.
Once a new coil of wire is unwound properly. it can be coiled down for running, the same as line Because of the general toughness and springiness cf the wire, a bight frequently may back up against yet: and try to flop the other way. When it does, don't fight the wire by trying to force down that bight,it will only spring up again.Throw that bight in a back turn and it will lie down.
If wire rope is being run off one reel to a winch drum or another reel, it should be run from top to top or from bottom to bottom.
Short lengths of wire rope may be made up in coils and stopped off tightly for stowage. When uncoiling wire rope, stand the coil on edge and roll it along the deck, uncoiling as you go, as in.
If a wire rope becomes kinked, never try to get the kink out by putting a strain on either part. As soon as a kink is noticed, uncross the ends pushing them apart. This method reverses the process that started the kink. Turn the bent portion over and place it on your knee or some firm object and push downward until the kink straightens out somewhat. Then lay it on a flat surface and pound it smooth with a wooden mallet.
Once a new coil of wire is unwound properly. it can be coiled down for running, the same as line Because of the general toughness and springiness cf the wire, a bight frequently may back up against yet: and try to flop the other way. When it does, don't fight the wire by trying to force down that bight,it will only spring up again.Throw that bight in a back turn and it will lie down.
CARE OF WIRE ROPE
Right laid wire should be taken right-handed around catheads and capstans to avoid kinking. A hard strain on a wire with a kink in it is even more disastrous than a strain on a kinked line. Kinks in wire must be avoided.
Wire that has been subjected to long usage wears like any other metal. The outer parts of the strands begin to flatten out, and as a result the diameter of the wire decreases. Individual strands of wire begin to wear through, and fishhooks appear here and there. A wire with an overstrain also shows a great many fishhooks, besides a marked decrease in diameter where the strain occurred. A wire containing fishhooks should never be used in boat falls, cargo whips, or other weight-carrying device for handling cargo, where so much depends on the strength of the wire.
Wire rope should be inspected frequently, checking for fishhooks, kinks, and worn out corroded spots. Worn spots show up as shiny flattened surfaces. To watch the wear you must know (1) the original diameter of the wire rope; (2) the present diameter of the wire rope at the worn area; and (3) the diameter of a single wire in one of the strands of the wire rope. The actual diameter is found by measuring with a micrometer or vernier caliper. Now, subtract the measured diameter of the wire rope from the original diameter. If the difference is half the diameter of the single wire, the safe working load of the wire rope is materially reduced. If the differences is equal to or greater than the diameter of the single wire, replace the rope. Even if no worn spots are apparent, wire rope should be measured occasionally to determine the overall wear. Take three or four measurements at intervals of several feet and find the mean. The same rule applies here as with worn spots: Replace the rope if the outer wires are worn to one half their original diameter.
Rusting and corrosion of the wires and deterioration of the fiber core sharply decrease the strength of a rope. It is impossible to estimate accurately the loss in strength from these effects.
Wire rope should not be stored in places where acid is or has been kept. The slightest trace of acid coming in contact with wire rope will damage it at that particular spot. Many times wire rope that has given away at one point has been found to be damaged by acid.
Prior to storage, wire rope should always be cleaned and lubricated. If the lubricant film is applied properly and the wire is stored in a dry place, corrosion is virtually eliminated.
The importance of lubricating wire rope is because wire is really a mechanical device with many moving parts. Each time a rope bends or straightens, the wires in the strands and the strands in the rope must slide upon each other, so a film of lubricant is needed on each moving part. Another important reason for lubrication is to prevent corrosion of the wires and deterioration of the hemp core.
Used wire ropes should be cleaned before they are lubricated. They may be cleaned with wire brushes, compressed air, or by superheated steam. The object is to remove all foreign material and old lubricant from the valleys between the strands and from the spaces between the outer wires. Lubricant may be applied with a brush and worked in well. Another method is to pass the wire rope through a trough or box containing the lubricant.
Commercial lubricants may be obtained. The best is a semiplastic compound, applied hot in a thinned condition. It penetrates while hot, then cools to a plastic filler, preventing the entrance of water. If a heavy strain was put on a wire rope with a kink in it, the rope can no longer be trusted. Cut out the kinked part and splice the ends together.
Frequently, abrasion or reverse or sharp bends cause individual wires to break and bend back. These breaks are known as fishhooks. If several occur at a point near each other, or several wires are broken along the wire rope's length, the safe working load is reduced greatly. When 4 percent of the total number of wires in the wire rope are found to have breaks within the length of one wire rope lay, the rope is unsafe for use. Consider the rope unsafe if three broken wires are found in one strand of 6x7 rope, six broken wires are found in one strand of 6x 19 rope, or nine broken wires are found in one strand of 6x37 rope.
Some common causes of wire rope failure include the following:
1. incorrect size, constuction, or grade.
2. Allowed to drag over obstacles.
3. Improperly lubricated.
4. Operated over sheaves and drums of inadequate size.
5. Overriding or crosswinding on drums.
6. Operating over sheaves and drums out of alignment.
7. Operating over sheaves and drums with improperly fitted grooves or broken flanges.
8. Permitted to jump sheaves.
9. Subjected to moisture or acid fumes.
10 Improperly attached fittings.
11.Permitted to untwist.
12. Subjected to excessive heat.
13. Destroyed by internal wear caused by grit penetrating between the strands and wires.
14. Subjected to severe overload because of inefficient operation.
15. Kinked condition.
Wire that has been subjected to long usage wears like any other metal. The outer parts of the strands begin to flatten out, and as a result the diameter of the wire decreases. Individual strands of wire begin to wear through, and fishhooks appear here and there. A wire with an overstrain also shows a great many fishhooks, besides a marked decrease in diameter where the strain occurred. A wire containing fishhooks should never be used in boat falls, cargo whips, or other weight-carrying device for handling cargo, where so much depends on the strength of the wire.
Wire rope should be inspected frequently, checking for fishhooks, kinks, and worn out corroded spots. Worn spots show up as shiny flattened surfaces. To watch the wear you must know (1) the original diameter of the wire rope; (2) the present diameter of the wire rope at the worn area; and (3) the diameter of a single wire in one of the strands of the wire rope. The actual diameter is found by measuring with a micrometer or vernier caliper. Now, subtract the measured diameter of the wire rope from the original diameter. If the difference is half the diameter of the single wire, the safe working load of the wire rope is materially reduced. If the differences is equal to or greater than the diameter of the single wire, replace the rope. Even if no worn spots are apparent, wire rope should be measured occasionally to determine the overall wear. Take three or four measurements at intervals of several feet and find the mean. The same rule applies here as with worn spots: Replace the rope if the outer wires are worn to one half their original diameter.
Rusting and corrosion of the wires and deterioration of the fiber core sharply decrease the strength of a rope. It is impossible to estimate accurately the loss in strength from these effects.
Wire rope should not be stored in places where acid is or has been kept. The slightest trace of acid coming in contact with wire rope will damage it at that particular spot. Many times wire rope that has given away at one point has been found to be damaged by acid.
Prior to storage, wire rope should always be cleaned and lubricated. If the lubricant film is applied properly and the wire is stored in a dry place, corrosion is virtually eliminated.
The importance of lubricating wire rope is because wire is really a mechanical device with many moving parts. Each time a rope bends or straightens, the wires in the strands and the strands in the rope must slide upon each other, so a film of lubricant is needed on each moving part. Another important reason for lubrication is to prevent corrosion of the wires and deterioration of the hemp core.
Used wire ropes should be cleaned before they are lubricated. They may be cleaned with wire brushes, compressed air, or by superheated steam. The object is to remove all foreign material and old lubricant from the valleys between the strands and from the spaces between the outer wires. Lubricant may be applied with a brush and worked in well. Another method is to pass the wire rope through a trough or box containing the lubricant.
Commercial lubricants may be obtained. The best is a semiplastic compound, applied hot in a thinned condition. It penetrates while hot, then cools to a plastic filler, preventing the entrance of water. If a heavy strain was put on a wire rope with a kink in it, the rope can no longer be trusted. Cut out the kinked part and splice the ends together.
Frequently, abrasion or reverse or sharp bends cause individual wires to break and bend back. These breaks are known as fishhooks. If several occur at a point near each other, or several wires are broken along the wire rope's length, the safe working load is reduced greatly. When 4 percent of the total number of wires in the wire rope are found to have breaks within the length of one wire rope lay, the rope is unsafe for use. Consider the rope unsafe if three broken wires are found in one strand of 6x7 rope, six broken wires are found in one strand of 6x 19 rope, or nine broken wires are found in one strand of 6x37 rope.
Some common causes of wire rope failure include the following:
1. incorrect size, constuction, or grade.
2. Allowed to drag over obstacles.
3. Improperly lubricated.
4. Operated over sheaves and drums of inadequate size.
5. Overriding or crosswinding on drums.
6. Operating over sheaves and drums out of alignment.
7. Operating over sheaves and drums with improperly fitted grooves or broken flanges.
8. Permitted to jump sheaves.
9. Subjected to moisture or acid fumes.
10 Improperly attached fittings.
11.Permitted to untwist.
12. Subjected to excessive heat.
13. Destroyed by internal wear caused by grit penetrating between the strands and wires.
14. Subjected to severe overload because of inefficient operation.
15. Kinked condition.
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