One to explain the concept
1,
Rated load G: refers to the crane during normal working hours, the
allowable maximum weight (including separable spreader weight), the unit
in tons (t) represents.
2, the load state Q: It is a reflection of the crane load times change and load change program parameters. Usually nominal load spectral coefficients Kp to represent. Kp
by the actual lifting load Pi and maximum lifting load Pmax and lifting
loads ni and the total number of operating cycles N ratio to represent,
the formula is:
Nominal size of the load spectrum in turn divided into several Kp Q 1-Q 4 special light weight four levels (see table below).
|
Load state
|
The number of nominal load spectrum
K F
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Explanation
|
|
Q1 - Light
|
0.125
|
Few lifting rated load, generally slight lifting loads
|
|
Q2 - in
|
0.25
|
Sometimes lifting the rated load, general lifting moderate loads
|
|
Q3 - Heavy
|
0.5
|
Frequent lifting rated load, general lifting heavier loads
|
|
Q4 - especially heavy
|
1.0
|
Frequent lifting rated load
|
3, the use of class: it reflects the life cycle of crane design frequency of use. The total number of cycles N represents the work, from small to big in turn divided into U 0-U 9 ten levels (see table below)
|
Utilization level
|
The total operating cycles
N
|
Note
|
|
U 0
|
1.6 × 10 4
|
Do not often use
|
|
U 1
|
3.2 × 10 4
|
|
|
U 2
|
6.3 × 10 4
|
|
|
U 3
|
1.25 × 10 5
|
|
|
U 4
|
2.5 × 10 5
|
Often lightly to use
|
|
U 5
|
5 × 10 5
|
Frequently used medium
|
|
U 6
|
1 × 10 6
|
Used infrequently busy
|
|
U 7
|
2 × 10 6
|
Heavy use
|
|
U 8
|
4 × 10 6
|
|
|
U 9
|
> 4 × 10 6
|
4, the working class A: It reflects the state of the load and use the crane busy two aspects of the job characteristics. Working-level division level by the use of a crane load state Q U and decisions. They are divided into A 1 ~ A 8 eight levels (see table below).
Crane working level, which is the metal structure of the working-level, determined by the hoisting mechanism is divided into A 1-A 8 grade and China if the type of work required crane control, largely equivalent: A 1-A 4 - Light; A 5-A 6 - medium; A 7 - heavy, A 8 - especially heavy.
|
Load state
|
The number of nominal load spectrum
KF
|
Utilization level
|
|
U0 U1 U2 U3 U4 U5 U6 U7 U8 U9
|
||
|
Q1 - Light
|
0.125
|
A1 A2 A3 A4 A5 A6 A7 A8
|
|
Q2 - in
|
0.25
|
A1 A2 A3 A4 A5 A6 A7 A8
|
|
Q3 - Heavy
|
0.5
|
A1 A2 A3 A4 A5 A6 A7 A8
|
|
Q4 - especially heavy
|
1.0
|
A2 A3 A4 A5 A6 A7 A8
|
Second, a correct understanding of the difference between them
Light-load state Q 1-Q 4 is especially heavy lifting crane in terms of full load level changes,
although able to work at full load, but the full extent is different, if
frequent load; plenty often full; some occasional full. Therefore,
in the design and manufacture of the safety factor used is different,
materials and structures, there are strict distinction, and the price
changes as well.
Working
class is a comprehensive reflection of the crane busy at work extent
and timing aspects of the full extent of lifting properties. It
can be seen working level is low, it may be particularly heavy cranes,
and working-level is high, there may be light crane, can not be
considered high-level work is a special heavy-duty, low-level work is
light.
In
addition, the level of the crane working level, from the weight does
not depend on the size of the load and the load from the weight depends
on the frequency of changing and busy engineering changes.
Third, strict "three simultaneous", the correct selection of cranes
"Labor
Law" and "Production Safety Law" on labor safety and sanitation
facilities have a strict requirement that new construction, renovation,
expansion project labor safety and sanitation facilities with the main
project must be designed, constructed and put into production and use. As
an authorized technician only grasp of the relevant national standards
and expertise in order to better grasp the "three simultaneous"
authority.
From the "working-level crane division" can be seen in the table, there are four levels of loading conditions. Busy with eight levels, many types of cranes. Then, choose which one of the most appropriate? We adopted the following two examples illustrate the use of this table.
Example 1. Installation and maintenance of a power plant with a 500-ton crane, you should choose what type of crane.
According
to the crane working conditions, ie, the operating frequency is low,
lifting work is generally at full load condition, you should select the
operating level A 1 ~ A 3-type crane would be more appropriate to meet the requirements in terms of performance, but also on the price comparison economy.
If you choose to work according to their starting weight class A 7 ~ A 8-type cranes, the larger waste of money.
Example 2. A foreign trade company warehouse frequently used 5 t crane, you should choose what type of crane.
According
to the crane working conditions, ie, higher operating frequency,
lifting load is generally moderate load condition, you should select the
working level in the A 6 ~ A 7-type crane is more appropriate, although the price is higher, but the work can be completed frequently.
If you choose from the weight according to A 1 ~ A 3-type cranes, although it can be used, but there may often fails, life is short, you can not complete the daily busy work.
These
two examples illustrate the "three simultaneous" approval, the security
must be aware of the crane mechanic working conditions, the crane can
be a reasonable choice, to ensure the safest and most economical price
state, to achieve optimal results.
