Project Case

Working system of weihua crane (relationship between load state, lifting weight and working level of crane)

(For crane selection and quotation, please email to info@hnwhcrane.net, thanks.)

Years of crane manufacturing and crane safety management work make us weihua crane found that some workers in the lifting equipment "three at the same time" review confused the crane load state, lifting weight and working level is one thing, that is, the higher the working level, the higher the load state;The lower the working level, the lower the load state;Or the crane rated load is bigger, the work level is higher;The lower the rated load of crane, the lower the working level.The main reason for this error is that the concept of working level, load state and load capacity of the crane is not clear.In the "three at the same time" when the audit often caused errors.First, the "big belt and small belt" has wasted funds; second, the "small belt and big belt" has buried the hidden danger of accidents.In order to attract people's attention, master the relationship between them, and facilitate our application in production practice, the following three parts are discussed:

I. expound relevant concepts

1. Rated load G

Refers to the maximum allowable lifting momentum (including the weight of separable spars) of a crane in normal operation, expressed in tons (t).

2. Load state Q

It is a parameter reflecting the change of crane load and the change of load action times.It is usually expressed as the nominal load spectral coefficient Kp.Kp is expressed by the ratio of the actual lifting load Pi to the maximum lifting load Pmax and the number of lifting loads ni to the total number of working cycles N, and the formula is:

According to the nominal load spectrum system Kp size is divided into four levels of Q1 light - Q4 heavy.

3. Utilization level

It reflects the frequency of crane design life cycle.Denoted by the total number of working cycles N, it is successively divided into 10 levels of u0-u9 from small to large

U0-u3 cranes are not often used

U4 cranes are often used sparingly

U5 cranes are often used in moderate conditions

U6 cranes are often used busily

U7-u9 cranes are in heavy use

4. Work level A

It reflects the working characteristics of crane in load condition and utilization busy degree.

The division of working level is determined by the utilization grade U and load state Q of the crane.They are divided into eight levels, A1 ~ A8.

The working level of the crane, that is, the working level of the metal structure, according to the lifting mechanism, divided into a1-a8, if compared with the crane work type stipulated in China, roughly equivalent: a1-a4-light;A5 - A6 -;A7- heavy, A8- extra heavy.

Second, correctly recognize the differences between them

Load state Q1 light -Q4 heavy refers to the crane in the lifting weight full load degree change, although can work in full load, but the degree of full load is not the same, such as some frequent full load;Some are often fully loaded;Some are occasionally full.The safety coefficient that USES when designing manufacturing so is different, with makings and structural respect have strict divisional, and price change is bigger also.

Working level is a comprehensive reflection of the crane in the working time of the busy degree and lifting weight of the full load of the characteristics.It can be seen that when the working level is low, it may be an extra-heavy crane, while when the working level is high, it may be a light crane. It cannot be considered that the working level is high and the working level is low and light.

In addition, the level of crane work, does not depend on the size of the lifting weight, but depends on the lifting weight load and load frequency changes and engineering busy degree changes.

Three, strict "three at the same time", the correct choice of crane

"Labor law" and "safe production law" have strict regulation to establishment of safe and wholesome labor, namely the establishment of safe and wholesome labor that builds, rebuild, expand a project must be designed with main body project at the same time, at the same time construction, put into production and use at the same time.As the author of Ann mechanic only master the relevant national standards and professional knowledge, in order to better grasp the "three at the same time" the right to review.

It can be seen from the table of "classification of crane working level" that the load state has four grades.Busy degree has 8 grades, crane type is more.So which is the best choice?Let's illustrate the use of this table with two examples.

For crane selection and quotation, please email to info@hnwhcrane.net, thanks.