Lifting machinery is divided into four categories, namely light and small lifting equipment, bridge cranes, cantilever cranes, and stacking cranes. The most used of these four types is the bridge crane. In fact, there are many types of bridge cranes. There are corresponding bridge cranes for different industries and different applications. Next, I will share with you. Classification of bridge cranes:
1. hook bridge
It occupies a large number in lifting machinery and has a wide range of uses. It is composed of a bridge (carriage), a trolley, a bridge operating mechanism, a bridge metal structure and electrical control equipment. Generally speaking, the crane with a lifting weight of less than 10 tons (t) adopts a set of lifting mechanisms, that is, one hook; for those over 15 tons, two sets of main and auxiliary lifting mechanisms are used, that is, two hooks. The hook with the larger lifting capacity is the main hook, and the hook with the smaller lifting capacity is the auxiliary hook. The main hook has a large lifting capacity, but the lifting speed is slow. The auxiliary hook has a small lifting weight, but the lifting speed is fast, which can improve the efficiency of light-load lifting. The lifting capacity of the main hook and auxiliary hook is generally expressed as the main hook/auxiliary hook, usually expressed in numbers, such as 20/5, that is, the main hook lifting capacity is 20 tons, and the auxiliary hook lifting capacity is 5 tons. The main and auxiliary hooks are sometimes called large and small hooks, and the ratio of their lifting weights is generally 1/6 to 1/4. Its lifting weight series is stipulated in ministerial standards as 3 to 250 tons.
2. grab bridge
It only has one more grab than the hook bridge type. The difference between them is the difference in the fetching device. The hook bridge-type retrieval device is a hook, and the grab bridge-type retrieval device is a grab. Due to the different retrieval devices, their functions are also different. The hook bridge type mainly lifts the whole bundled objects, while the grab bridge type mainly lifts the loose materials that are not easy to be bundled. The grab bridge type is also a special crane, and there are two types of four-rope grabs and electric grabs. This kind of lifting weight series is stipulated in the ministerial standard as 3 to 20 tons.
3. Electromagnetic bridge
The basic structure of the electromagnetic bridge type (also known as the lifting electromagnet) is basically the same as that of the hook bridge type. Magnetically conductive metal materials, such as steel plates, section steel and scrap steel, etc., especially scattered magnetically conductive metal materials. The lifting capacity of this crane is 5, 10, 15, 20, 30 tons.
4. Hook, grab, electromagnetic bridge type
It is a multi-purpose lifting equipment with the same structure as the hook bridge except for the picking device. Because it has three kinds of fetching devices: hook, electric grab, and electro-magnetic disk, it can use any one of them according to different working properties. This should be used for production sites where materials change frequently. The electric disk uses direct current, and the electric grab uses alternating current, so the power supply should be changed through a switch when in use. There are two kinds of lifting weights of 5 and 10 tons.
5. Dual-purpose bridge
It has two types, one is hook bridge type and grab bucket, and the other is bridge type electromagnetic and grab bucket. Its characteristic is that a trolley is provided with two sets of independent lifting mechanisms. One set is for hook and one set is for grab bucket, or one set is for lifting electromagnet and one set is for grab bucket. Although two sets of hoisting mechanisms cannot be used at the same time, it is not necessary to remove the other one when using one of the fetching devices like the hook, grab, and electromagnetic bridge. In this way, it can be arbitrarily selected according to the needs of the work, so it has higher production efficiency than the three-purpose.
6. Double trolley bridge
It has two lifting trolleys with the same lifting capacity, which can work alone or in combination. The two trolleys of some double trolleys (such as 2³50 tons, 2³75 tons) are equipped with a variable-speed hoisting mechanism, so high-speed operation can be used for light loads, and low-speed operation can be used for heavy loads; when lifting heavier objects , two trolleys can be hoisted at the same time. Since this kind of crane has two trolleys, and one or two trolleys are used according to different working conditions, it is most suitable for lifting long workpieces when using two trolleys. This kind of effective working range is wide, and its lifting weight is 2x 2.5, 2³5, 2³10, 2³20, 2³30 tons
The above is the classification of bridge cranes shared for everyone. Welcome to exchange knowledge about lifting equipment!