Crane Basics (Part 3)

5. Points to note for renovating old factory buildings:

The machine's overall limit dimensions, wheel pressure, service class, lifting and traveling speeds, and lifting height, among other specifications.

 

6. Data that the design institute needs to know ;

1 • Crane rail installation dimensions. 2 · Crane power supply trolley installation dimensions.

3 • Crane wheel load distribution diagram. 4 • Crane weight.

5 • Vehicle weight. 6 • Collision loads of the crane.

7 • The limit dimensions of the hook. 8 - The limit dimensions and overall dimensions of the crane.

9 - Total power of the crane, as well as the motor models and power ratings for each crane mechanism.

 

7. The door opening direction of the driver's cab ;

A1 : Open the door on the left end. A2: Open on the left side. A3: Open from the right end. A4: Open door on the right side.

The driver's cab can easily be designed with a walkway outside the door; in this case, the door should open outward, and a interlock protection device must be installed on the walkway door. If there’s no walkway outside the driver’s cab door, the door should open inward instead, with the interlock mechanism placed at the entrance to the cab. Additionally, whether or not there’s a walkway outside the cab door, a sliding door can also be used as an alternative.

 

8. There are several types of special cranes:

1、 What is an insulated crane, and how is it insulated?

Insulated cranes are primarily used in metallurgical environments such as non-ferrous metal electrolysis plants for aluminum, magnesium, lead, zinc, and other metals. These cranes feature an insulated connection between the hoist hook or other lifting attachments and the trolley. Typically, the crane is equipped with three layers of insulation: between the hook and the pulley, between the lifting mechanism and the trolley frame, and between the trolley carriage and the main trolley itself. The insulation principle relies on using high-quality, thermosetting resin-based industrial-grade rigid circular laminated tubes and rods—insulating materials specifically designed for electrical applications—to ensure reliable insulation throughout these critical connections.

2、 What is an explosion-proof crane; classification levels 。

An explosion-proof crane is a crane designed to operate safely in hazardous, potentially explosive environments such as those containing explosive gases. Explosion-proof cranes are classified based on whether their electrical equipment meets the criteria for either the maximum experimental safety gap or the minimum ignition current ratio of explosive gas mixtures. A/B/C Class III, and according to the explosion-proof type, there are several varieties, including flameproof and increased safety types, among others.

Explosion-proof rating classification:

 

Explosion-proof marking	Temperature Category
	T1	T2	T3	T4
IIA	Propane, ethane, carbon monoxide, acetone, acetic acid, ammonia, and more.	Ethanol, butane, ethylene vinyl acetate, dichloroethane, vinyl chloride, ethyl chlorohydrin, dimethylamine, and more.	Turpentine, naphtha, petroleum—including motor gasoline and fuel oil, among others.	Acetic acid, trimethylamine, and more.
IIB	Propyne, rare gas mixtures like propyne, and more.	Ethylene, ethylene oxide propylene glycol methyl ether, furan, and more.	Dimethyl ether, vinyl sulfide, hydrogen sulfide, and others.	Ethyl methyl ether, diethyl ether, dibutyl ether, tetrachloroethylene, and more
IIC	Hydrogen, water gas.	Acetylene.

IIC Grade acetylene should be specified in the purchase contract.

3、 Anti-corrosion cranes, metallurgical cranes, cranes specifically designed for hydropower stations, and their key features ：

* Anti-corrosion cranes are cranes designed to operate effectively in corrosive environments, such as those with corrosive gases or other highly corrosive media.

Its main feature is the application of anti-corrosion paint—or other methods—onto metal structures and components, effectively isolating them from corrosive gases or liquids to achieve corrosion protection.

* Metallurgical cranes are specially designed lifting equipment suited for the demanding requirements of hot processing applications such as metal smelting. These include open-hearth charging bridge cranes, material bin cranes, mold-handling cranes, lid-lifting cranes, casting cranes, and quenching cranes, among others.

Its main feature is that it operates specifically within the entire metal smelting process, and its operational level is typically high, often reaching A7~A8 Additionally, the working environment features high dust levels and elevated temperatures, necessitating the use of insulation devices and similar equipment.

* Dedicated cranes for hydropower stations include two types: first, the powerhouse bridge crane; and second, the gate hoist and tailrace gate operator located atop the dam.

Factory bridge cranes: Due to the varying rotational speeds of generator prime movers, hydroelectric units require bridge cranes with greater lifting capacity compared to those used in thermal power plants. A key feature of their operation is that the largest-capacity bridge crane is installed only once—after which it is essentially used on a permanent basis. 10 Annual maintenance is carried out sequentially, utilizing the maximum lifting capacity, while daily tasks primarily involve moving small objects—though these are used very infrequently.

Dam-top gantry crane: Due to the varying dam structures, the crane's trolley tracks are available in both straight and curved configurations. The system is required to display the lifting height, with a typical error margin not exceeding 3mm At the same time, consider maintenance of the trash rack by equipping the upstream-side support legs with a slewing crane or installing dual electric hoists on the end-beam side.

 

Nine: How a rail-mounted crane crosses tracks:

Track-crossing hoists primarily achieve track crossing via a track-crossing docking mechanism. This mechanism consists of components such as an electric pushrod, stoppers, and buffers. When no track crossing is required, the stoppers and buffers remain in their vertical positions. However, when track crossing is needed, the electric pushrod within the docking system activates, extending forward to engage with the positioning toggle fork, securely linking the two lifting devices together. At the same time, the stoppers and buffers pivot into a horizontal position, allowing the electric hoist to pass smoothly and successfully completing the track-crossing process.

 

10. How a grab crane works:

This crane features a standard grab bucket designed to lift loose materials. Four steel cables are suspended from both the opening/closing mechanism and its upgraded hook, allowing the open bucket to descend onto the material. First, the opening/closing mechanism is activated; as it closes, the material gets securely trapped inside the bucket. Once the bucket is fully closed, the lifting mechanism immediately engages, simultaneously loading all four steel cables to begin the lifting process. When it’s time to unload, only the opening/closing mechanism is activated, causing the bucket jaws to instantly open and release the material. Alternatively, the crane can also be equipped with a motorized grab bucket—this type includes its own built-in opening/closing system, requiring just the hook for lifting and lowering operations. In this way, the crane can perform the same functions as a conventional grab-bucket model.

 

11. Notes on Placing Orders ：

1 • Model name. 2 • Work level. 3 , Speed of each institution.

4 • Altitude. 5 1. Cantilever effective length. 6 , Lifting capacity.

7 • Manipulative behavior. 8 – Single and double braking. 9 , Usage scenarios.

10 , Crane color. 11 , Span. 12 • Speed control method.

13 • Ambient temperature. 14 • Humidity. 15 , Crane power supply method.

16 , Lifting height ( On-track, off-track ) 17 • Cab type and door opening direction.

18 • Requirements for manufacturers of key components. 19 · Crane rail model.

If you have any other specific questions, please raise them separately—such as the vehicle's method of conducting electricity, for example.

 

12. Characteristics of Overhead Gantry Crane Operation :

* The span is relatively large—typically exceeding 40m. The span typically ranges from 40m / 50m / 60m 。

* The gantry crane structure features one rigid and one flexible support leg.

* The main girders of the loading and unloading bridge are available in box-type and truss designs.

* Work characteristics of the gantry crane: high lifting speed, typically in 50m/mi