Civil Engineering Reference
In-Depth Information
The rope tensile force S
A
on the first sheave has an important influence on the
minimum weight force of the hook block. This rope tensile force depends on the
arrangement of the drum and the sheaves. In the simplest case—the drum is situated
vertically below the first sheave—the rope tensile force S
A
is then equal to the weight
force of the rope piece between the drum and the first sheave. Thereby, as mentioned
before, it is presupposed that all the stationary sheaves are located at the same height.
Example 3.16 Lowering an empty hook block
The data of the crane are the same as for Example 3.16 with, in addition, at the
first stationary sheave for the weight force of the vertical rope piece with a length
h = 20 m above the drum, the rope tensile force is S
A
= W gh= 177 N.
According to (
3.122
), the minimum weight force of the empty hook block is
7
:
07
15
2
þ
0
:
416
177
20
þ
1
:
33
0
:
416
8
þ
2
2
8
1
2
Q
H90
¼ 8
177
þ
8
þ
2
¼ 1
;
416
þ
1
;
417 ¼ 2
;
833 N
:
The minimum weight of the hook block is then 289 kg.
For very low temperatures with an appropriate lubricant, the force loss by
friction may be doubled. Then the minimum mass force is
Q
H90cold
¼ 1
;
416
þ
2
;
834 ¼ 4
;
250 N
:
and the minimum weight of the hook block is 433 kg.
The necessary minimum weight can be calculated with the help of the Excel-
program ''WIRKUNG2.XLS''.
References
Aberkrom, P.: Seilzugkräfte in Treibscheibenaufzügen. Lift-Report 15(2), S15-S20 (1989)
Andorfer, K.: Die Zugkraftverteilung in schwingend beanspruchten geraden Drahtseilen. Diss
Techn. Universität Graz (1983)
Apel, G.: Beitrag zur Optimierung sicherheitsrelevanter Eigenschaften korrosionsgeschützer,
hochfester Stahldrahtseil. Diss. Universität, Wuppertal (1981)
Arnold, H., Hackenberg, W.: Seilatlas für Zugseile UndStreck-Enförderanlagen. Verlag Glückauf
GmbH, Essen (1971)
Babel, H.: Metallische und nichtmetallische futterwerkstoffe für aufzugtreibscheiben. Diss. TH
Karlsruhe (1980)
Bahke, E.: 150 Jahre Lebensdaueruntersuchung von Seildraht und Drahtseil. In: Int: Kolloquium
150 Jahre Drahtseil. Techn. Akademie Esslingen, 13-14 Sept 1984
Bechtloff,
G.:
Die
Beanspruchung
des
Drahtseilquerschnittes
unter
ebener
Querpressung.
Drahtwelt 55(2), S80-S87 (1969); 3, S147-S158 and 4, S196-S203
Bechtloff, G., Szelagowski, P.: Höhere Lebensdauer von Drahtseilen durh verbesserte Seilrollen.
Fördern und Heben 17(6), S337-S342 (1967)
Beck, W., Briem, U.: Correlation between the estimated and actual (service life of running ropes.
WIRE 45(6), 333-335 (1995)
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