Wire
rope will develop 100% efficiency, that is, break at or above minimum acceptance
strength (not less than 2 1/2% below normal breaking strength) under controlled
laboratory conditions.Once fittings such as sleeves, clips, sockets, etc. are
attached and/or the wire rope passes over a curved surface such as sheaves,
pins, etc. its strength is decreased. In the case of wire rope passing over
a curved surface this decrease in strength depends on the severity of the bend.
In the case of wire rope fittings, the decrease in wire rope strength will
depend on the type of fitting used. The wire rope efficiency usually ranges
from 70% - 100%. Note, that hand spliced wire rope, while not using any fittings,
has less efficiency than properly flemished and swaged wire rope. There are
other factors, depending on the application of wire rope, that can cause a
decrease in nominal wire rope strength. They must be considered when choosing
a design factor. Refer to the Wire Rope Users Manual and/or other qualified
sources for details.
Elastic Properties of Wire Rope
Wire rope is an elastic member; it stretches or elongates under load. This elongation can be permanent or recoverable. The extent of elongation will depend on the wire rope used and the design factor chosen. While it may be acceptable for many wire rope uses to neglect its elastic properties, they are of critical importance for some uses. When in doubt about the importance of wire rope elongation consult professional help. Pre-stretching wire rope will only remove some of the constructional stretch and will not totally eliminate elongation under load.
Winding Wire Rope on Drums
Installation of wire rope on a plain or grooved drum requires a great deal of care. Make certain the wire rope is properly attached to the drum. Keep adequate tension on the wire rope as it is wound onto the drum.Guide each wrap as close to the preceding wrap as possible, or follow the groove in case of a grooved drum. No blanket recommendations can be given concerning direction of winding, desirable drum diameter, fleet angle, etc. Consult the Wire Rope Users Manual for this and other important technical information.
Wire Rope Slings
Refer to ASME standard B30.9 and OSHA standard 1910.184 for design factors and other important information. Other standards and information may apply.
Reel Capacity
It is virtually impossible to calculate the precise length of wire rope that can be spooled on a reel or drum. The formula below provides a sufficiently close approximation based on uniform rope winding on the reel.
Elastic Properties of Wire Rope
Wire rope is an elastic member; it stretches or elongates under load. This elongation can be permanent or recoverable. The extent of elongation will depend on the wire rope used and the design factor chosen. While it may be acceptable for many wire rope uses to neglect its elastic properties, they are of critical importance for some uses. When in doubt about the importance of wire rope elongation consult professional help. Pre-stretching wire rope will only remove some of the constructional stretch and will not totally eliminate elongation under load.
Winding Wire Rope on Drums
Installation of wire rope on a plain or grooved drum requires a great deal of care. Make certain the wire rope is properly attached to the drum. Keep adequate tension on the wire rope as it is wound onto the drum.Guide each wrap as close to the preceding wrap as possible, or follow the groove in case of a grooved drum. No blanket recommendations can be given concerning direction of winding, desirable drum diameter, fleet angle, etc. Consult the Wire Rope Users Manual for this and other important technical information.
Wire Rope Slings
Refer to ASME standard B30.9 and OSHA standard 1910.184 for design factors and other important information. Other standards and information may apply.
Reel Capacity
It is virtually impossible to calculate the precise length of wire rope that can be spooled on a reel or drum. The formula below provides a sufficiently close approximation based on uniform rope winding on the reel.
| L = length of wire rope in feet A = depth of rope space on reel in inches B = width of drum between flanges in inches D = barrel diameter in inches K = constant for given wire rope diameter (per table below) H = diameter in reel flange in inches X = clearance |
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