twin-path® slings in action - Hanes Supply, Inc

Winch linesYOUR SLING AND RIGGING SPECIALISTcleanInGSometimes utilities have adopted the very good practice of carryingat all times, a spare (clean and dry) winch line enclosed in aplastic bag, enabling crews in the field to quickly replace a damaged,soiled or wet winch line. Samson winch lines can bewashed in a mild detergent and warm water, rinsed and air-dried.The polyester fibers themselves actually absorb only a negligibleamount of water, but water trapped between the fibers should besqueezed out (by placing the line under tension) and air-dried.sHock loaDInGShock loading of any line – synthetic, manila, or wire – producesa drastically different set of physical properties and results ascompared with normal loading. Shock loading, most simply described,is a "jerking" or "snatching" or a line. Or, a very suddenchange in tension – from a state of relaxation or low load to oneof high load. This results in accelerated wearing.A typical shock load on a winch line occurs when an object is liftedvertically with a sudden jerk, or when this load is suddenlydropped. A 5,000 pound load, under these conditions, may then"weigh" 30,000 pounds – and break a winch line rated in thisstrength range.A 4" sudden drop – as off a platform – can actually double theload. Similarly, an over-wrap "falling off" the winch drum can resultin a 50% shock load.Assume that you have seven identical ropes – each with a 30,000lb. breaking strength – and you work these ropes daily – eachrope lifting a different load, as below – for example, in a winch lineapplication:WoRkInG no. of lIftsbReakInG WoRkInG loaD befoRestRenGtH loaD factoR faIlURe*1. 30,000 lbs. 5,000 lbs. 6/1 1,0002. 30,000 lbs. 6,000 lbs. 5/1 7503. 30,000 lbs. 7,500 lbs. 4/1 5004. 30,000 lbs. 10,000 lbs. 3/1 3005. 30,000 lbs. 15,000 lbs. 2/1 1006. 30,000 lbs. 20,000 lbs. 1.5/1 257. 30,000 lbs. 28,000 lbs. 1.1/1 5*Relative values onlyThis illustration clearly shows the higher the Working Load Factorthe greater the Service Life, and the lower the replacement factor.Thus, a Working Load Factor also related directly as an "EconomyFactor."Your may turn this around and look at it another way: If you're alwayslifting the same weight; then, the stronger the rope (andhigher the Working Load Factor) – the longer the rope will last.in order to prolong the life of the line and reduce premature downgrading. If there is reason to believe that a line has been shockloaded above its recommended working load, it should be logged;and if a number of these occur, the line should be rotated andinspected.VIsUal InsPectIonThe load-bearing capacity of Double Braided Ropes are dividedequally between the inner core and the outer cover – thus, despitedamage to the outer cover strands, you have an intact innercore capable of supporting approximately 50% of the appliedload... an important reserve safety factor. Spectron II has 100% ofits load bearing capacity accomplished by the core.DIscaRD PoIntContinued use and normal wear in the line gradually diminishesthe ultimate bearing strength and lowers the factor of safety. Indetermining the proper discard time of Braided Winch Lines, thefollowing guides are suggested:a. If as many as 1/2 of the cover strands are cut at a givenpoint, this damaged section should be cut out. If within 10 feetof the eye, put in a new eye splice. If over 10 feet, rejoin therope with a Standard End-for-End Splice. The rope can then beput back into normal operation. A few damaged strands spacedout along the rope at intervals is no real cause for immediateconcern, but should be watched and periodically examined.b. If the individual cover strands have been worn down afterextended use to within 50% of their original bulk over anextended area of the line, then the line should be discarded (orassigned to a less critical task). This can best be determined byan examination and comparison of the bulk of an individualstrand which is exposed and subject to wear with the samestrand where it crosses under other strands and is protected(and therefore is full size).c. Another guide for determining discard time is when the ropehas a residual strength of 50% of its original new rope strength.This can be determined through laboratory tensile strengthbreak tests. This can be done by Hanes Supply. If utilities wishto perform their own tests, they should contact Hanes Supplyto coordinate testing procedure, methods and apparatus. HanesSupply has instructions on technical procedures for testingbraided synthetic ropes.tRaInInGA Preventative Maintenance and Safety Program in the use ofwinch lines is strongly recommended. Hanes Supply will assist inthis.Samson winch lines, used and cared for properly, will render yearsof efficient, economical, and trouble-free service.Winch line replacements, either in cut lengths or 600 ft. spoolsare available through Hanes Supply.fatIGUeSynthetic fibers have a "memory." They function similar to metal(wire) in that they remember and retain the effects of being overloadedand shock loaded. This is an important reason to stresswinch line procedures which reduce danger of shock loading,HEADQUARTERS: 55 James E. Casey Drive • Buffalo, NY 14206 PHONE: 716.826.2636 FAX: 716.826.4412 www.hanessupply.com79