ADVANTAGES AND AVAILABILITYThe Ropeblock sheave promotes wire rope longevity and helps prevent block rotation or cabling, adding to a lower total cost of ownership and a higher crane uptime. Ropeblock sheaves are accepted by all major class societies.

The design has proven itself in over twenty years of use and has led to being available in hundreds of different bearing and D/d sizes, ranging from wire rope 10 mm to 76 mm or bigger and a very cost effective solution. WEAR The notably better wear resistance in Ropeblock sheaves in comparison to other materials is primarily explained by the graphite as established before in third party testing. Once the rope and groove are a pair (are run in), the wear almost stops because of its inherit graphite, and shows wear performance equal to (new) hardened sheaves. Rope replacements with the same diameter do not create new wear because of the graphite that came free working the sheave. In the second instance, a special manufacturing technique is used to create a higher than standard hardness in the groove, optimizing the sheave durability. SERVICERopeblock sheaves have a higher than average low temperature performance, allowing service down to even -40°C/-40°F. The improved ductility in the Ropeblock sheave allows better resistance against impact or other unintended blows against objects and the material grain makes it more crack-resistant.

Contact us or our sales representatives for information or availability regarding your application.

ROPEBLOCK B.V.

Ropeblock B.V. is a leading engineering and manufacturing specialist for the lifting and

wire rope industry in many aspects. Our mechanical lifting and hoisting components

are used in practically all sectors involving machinery for lifting, hoisting, and transporting

materials. They are used in critical machinery such as in ports, on ships and offshore

platforms, construction, mining, dredging and in heavy industry, operating success-

fully on all continents, both underwater as well as on today’s highest skyscrapers.

Many of the leading crane and wire rope manufacturers in the world are familiar with

our products and our standard of quality and safety. Exports from the Netherlands

represent 95% of our sales, and our products comply with the very demanding

international regulations and standards.

www.ropeblock.com

Ropeblock sheaves - Engineered for durability

www.ropeblock.com

Ropeblock B.V. PO Box 391 I NL-7570 AJ Oldenzaal I The Netherlands T +31 (0)541 532 300 I F +31 (0)541 536 575 I E sales@ropeblock.com

Copyright©2016Published by Ropeblock B.V. All rights reserved - 0916/VV/SCRA

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wire rope interaction available!

In the past two decades, Ropeblock has put sheaves on

the market that we believed to perform the best in wire

rope interaction and would generate the most Cycle

Bends Over Sheave (CBOS) in its numerous applications.

Use in countless construction, cargo handling, offshore

and industry applications in over these twenty years,

continuously confirmed this belief in the form of our

(OEM) customer feedback.

CYCLE BENDS OVER SHEAVE IN A TWISTED STATEWhen a wire rope is bent over a sheave, the wire rope

is fatigued. Since university studies in 2015, it has been

known that a wire rope is even more fatigued when it

is bent over a sheave in a twisted state. These university

studies show durability reductions in commonly seen

twisted states of wire rope of up to 70% in the most

commonly used rotation resistant ropes.

FLEET ANGLES AND TWIST In nearly all crane applications, fleet

angles (the angle of attack of the wire

rope on to the sheave groove) are the

main reason for the introduction of twist

in the wire rope while you are working

the crane. The type of operation ran is of

great influence on the amount of twist

generated in the system.

BLOCK ROTATION OR CABLING

Wire ropes come with their type designated torque factor.

Under tension, this implies the end of the wire rope wants

to rotate when free (e.g. with a swivel), but cannot when

fixed directly to the crane. The additional twist as a result

of the fleet angles generates extra torsion. When the

accumulated twist in your system is released between

the tip of the crane and the lower block, it may at one

point result in block rotation. The overtime buildup of

twist has then tipped the balance of a stable tackle to

a tackle with cabling.

WIRE ROPE - SHEAVE INTERACTION

A large part of the amount of wire rope twist is determined

by the coefficient of friction between the wire rope and

the sheave. In the older literature, plastic sheaves showed

the highest friction and the most twist. Metal sheaves

would perform better. Ropeblock introduced two decades

ago a metal sheave with dry lubrication in the form of

graphite leaving properties (in a function similar to bronze

bearings with graphite nodes) to lower the coefficient of

friction while it works with the wire rope and promotes

sliding of the wire rope, rather than twisting it.

CONFIRMATION BY COMPARISON TESTING

Because of the recent further study where the twisted

state of a wire rope would reduce longevity significantly,

Ropeblock launched a comparison investigation under

the optimal groove throat angle.

Here, it shows that the Ropeblock sheave performs 40%

better against twist than the same size and geometry plastic

sheave and approx. 25% better against twist compared to

a normal steel sheave of a similar size and geometry.

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