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| 1.2 VITAL INFORMATION ABOUT ROPES |
1.2.1 Measurement of Wire Rope Diameter
Rope diameter is the diameter of circle surrounding external rope wire and strands
and including all rope intersection. In rope measurement the jaws of the meter must
contact outer two strands (Diagram-6). Two measurements perpendicular to each other
are generally made on two points in the distance of at least 1 m.to each other and
averages of four measurements are required within tolerances. In case of disagreement
on standarts rope diameter should be measured under a certain guy.
Nominal halat Çapı Tolerans
Eksi Artı
3 mm kadar -0
+8%
3 mm ile 5 mm arası -0 +7%
5 mm 8 mm arası -0 +6%
8 mm üstü -0
+5%
Diagram-5. Method of Wire Rope Diameter Measurement
1.2.2. Lay Length Lay Length is the distance in which wire or the wire in the strand
progresses on horizontal axis when they make a complete helical flexion. This value
is given as “lay” or “lay length” which are supplied by multiplying the lay length
by rope diameter. The wire slay in the strand with parallel braiding are same and
wires contact each other linearly. They are in point contact in standart compositions.
1.2.3. Metallic Cross Sectional Area It is the total of nominal sectional areas
of wires in rope. This value is very important in ultimate breaking load calculations.
Thin filler wires are neglected in the calculation of metallic sectional area.
1.2.4. Resistance to Abrasion and Bending Fatigue Resistance to abrasion and bending
fatigue is shown as graphics in Diagram-7. On the middlemost x-point abrasion and
bending fatigue resistance generally is balanced and while moving up and down along
the axis a feature increases and the other decreases and vice versa.
Diagram -6. Flexibility and abrasion resistance tendency according to rope composition
1.2.5. Relations of reel, drum and rope Diameteres of reel and drum and diameters
of grooves and their other features have a substantial impact on the rope life.
Groove cutters may be used in measurements of groove abrasion, groove diameters
and groove length. Manufacturing drum and coils from the appropriate materials is
very important in terms of rope life. If grooves are wider and rope contact angle
is greater than the requisite round is seen in rope. If they are narrower and lesser
than the requisite wires and strands are stuck and wire moves are blocked. In both
cases rope life is decreased. In general, rope-groove contact angle must be between
135-150 degree (Diagram-8,9).
Diagram-7. Reel and Groove cross sections
a. New rope – new groove
b. New rope – worn groove
c. Wore rope – worn groove
Diagram-8. Some reel dimensions and use of Groove cutter
Table:2 Rates of coil and rope diameters
1.2.6 Deflection Angle Deflection angle (Diagram-10) is the angle between the two
lines drawn vertically from y, v center to the drum flange and drum center. There
are two types of deflection angle: Right deflection angle and left deflection angle.
They have considerable impact on winding of rope in use and, accordingly, on rope
life. Deflection angle mustn’t exceed 1.5 degree in smooth drums and 2 degree in
grooved drums in terms of operational efficiency and decreasing of rope life.
Diagram-9. Deflection Angle in the use of rope
1.2.8 Lubrication Lubrication of steel ropes is necessary not only for acquiring
preventive quality against oxidation and other corrosive agents but for ability
of sliding of wires and strands on each other in the correct way. However, this
is not enough to protect ropes for a long time. Therefore, user must lubricate them
again and again in certain periods depending on operational conditions.
In general, rope lubricants must
1. not include alkali and acids,
2. supply enough adhesion strength,
3. not dissolve in actual operational conditions,
4. be in viscosity enough to penetrate into wires and strands,
5. have high film resistance,
6. be resistance against oxidation and water and
7. not include any bacterial agent. Summary information about lubrication types
is given in Table-3.
1.2.9 Unwinding ropes Our ropes are delivered generally in the form of wrapped on
reels or in coils. When rope is put in circuit for use or transferring it is necessary
to comply with the measures in Diagram-11.
Diagram-10. Correct and wrong unwinding examples
Coilings that occur during the rope is unwinding cause undesired and lasting defects
in various types such as “torsion and eyelet” in next processess that preclude use
of rope.
Diagram-11. Defects caused by unwinding the rope in a wrong way
The ropes forming coiling and gam are irreparable. This kind of ropes are left out.
Manufacturers are not to blame for the damages caused by wrong use. In order to
give no way to similar cases transfer machines using a certain guy should be used
for untying processes and cutting processes for certain sizes. As ropes are components
of an operating system they should be subject to storage process rigorously. In
these activities contact between external factors that may effect rope quality and
ropes must be prevented. It should not be forgotten that ropes, as it is well seen
when they are examined at close range, consist of a large number of thin wires.
Therefore they are so sensitive against external factors.
1.2.10 Rotation Resistant Ropes
One should bear in mind that rotation resistant ropes are more sensitive than other
ropes during transferring, edge cutting and use. For this reason;
a. Either edges of the rotation resistant ropes must be bound tightly before cutting
them.
b. Transferring and cut to length line must be performed in transferring machines
appropriate for these activities according to the rules shown at Diagram 10.
c. If possible, rope must be lay down flatly before installing on crane and must
be allowed to rotate on its axis for removing internal strechings –if any. After
that, the rope bound to crane must be operated at least for an hour. Strand or steel
core must be allowed to move by making edges free in order to remove internal strechings,
and then the edges of ropes that have been cut again must be bound to crane by fixing
them properly. If rope is turned down and brings about a stress for any reason during
use above-mentioned edge cutting process should be repeated.
d. Instant loading must be avoided during use. Rope must be avoided passing through
the coils with small diameters and rubbing sharp corners. For this reason, it must
be paid attention to coefficient 42 given for coil diameter in Table-2 and at least
safety coefficient 8.
e. Instant discharge must be avoided while rotation resistant ropes are operating.
f. Edges of rotation resistant ropes must be bound before using and during cutting.
a. Rotation resistant ropes must not be rotated under load by effect of external
powers.
1.2.11 Marking of the Çelik Halt ve Tel San. A.Ş. There are green indentification
tapes inside our ropes read “ÇELİK HALAT VE TEL SAN A.Ş.” (green ropes are used
under 10 mm). Red strand is applied to the lubricated ropes in range of 10-45 mm
diameteres that are produced for Domestic Market. Dry (unlubricated) ropes are out
of this application. Sellers and users must check these markings in order to define
if products are belong to Çelik Halat ve Tel San A.Ş. or not or apply to our Company.
Page 10
Table 3. Lubrication Types
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