What Are The Types Of Bridge Cranes?

What Are The Types Of Bridge Cranes?
 

Bridge crane is a kind of bridge type crane whose bridge frame runs on elevated track, also known as overhead crane. The bridge frame of the bridge crane runs longitudinally along the rails laid on the elevated sides on both sides, and the hoisting trolley runs horizontally along the rails laid on the bridge frame, forming a rectangular working range, which can make full use of the space under the bridge frame for hoisting and transporting materials. Hindered by ground equipment.
 

Ordinary bridge cranes are generally composed of a lifting trolley, a bridge running mechanism, and a bridge metal structure. The lifting trolley is composed of three parts: the lifting mechanism, the trolley running mechanism and the trolley frame.
 

 

The lifting mechanism includes a motor, a brake, a reducer, a drum and a pulley block. The motor drives the reel to rotate through the reducer, so that the wire rope is wound on the reel or lowered from the reel to lift the heavy object. The trolley frame is a frame for supporting and installing components such as the lifting mechanism and the trolley running mechanism, and is usually a welded structure.
 

The crane operating mechanism generally only uses four driving and driven wheels. If the lifting capacity is large, the method of adding wheels is often used to reduce the wheel pressure. When there are more than four wheels, a hinged balance frame device must be used to distribute the load of the crane evenly on each wheel.
 

The metal structure of the bridge is composed of main girders and end girders, which are divided into two types: single main girder bridge and double girder bridge. The single girder bridge consists of a single main girder and end girders located on both sides of the span, and the double girder bridge consists of two main girders and end girders.
 

 

The main girder is rigidly connected with the end girder, and the two ends of the end girder are equipped with wheels to support the bridge running on the elevated. Rails are welded on the main girder for the trolley to run. There are many structural types of the main girder of the bridge, and the typical ones are box structure, four-truss structure and vierendeel truss structure.
 

The box-shaped structure can be divided into several types such as regular-track box-shaped double beams, partial-track box-shaped double-girders, and partial-track box-shaped single main girders. The box-shaped double girder on the right track is a basic form widely used. The main girder is composed of upper and lower flange plates and vertical webs on both sides. The trolley rail is arranged on the center line of the upper flange plate. Its structure is simple. It is easy to manufacture and is suitable for mass production, but it has a large dead weight.
 

The driving mode of the crane operating mechanism can be divided into two categories: one is centralized drive, that is, one motor is used to drive the long transmission shaft to drive the driving wheels on both sides; the other is separate drive, that is, the driving wheels on both sides use one Electric motor drive. Medium and small bridge cranes mostly use the "three-in-one" drive mode that combines brakes, reducers and motors. Ordinary bridge cranes with large lifting capacity are easy to install and adjust. The drive device often uses a universal coupling. .
 

The section of partial rail box-shaped double girder and partial rail box-shaped single main girder is composed of upper and lower flange plates and main and auxiliary webs of unequal thickness. The trolley rail is arranged above the main web.

 

 

The slab can be omitted, and the off-track box-shaped single main girder is replaced by a wide-flange box-shaped main girder for two main girders. The self-weight is small, but the manufacturing is more complicated.
 

The four-truss structure is composed of four planar trusses to form a closed space structure. The surface of the upper horizontal truss is generally covered with a walking platform, which has light weight and high rigidity. Less strong and less produced.
 

The vierendeel truss structure is similar to the partial rail box-shaped main girder, which is composed of four steel plates to form a closed structure. Except the main web is a solid-web I-shaped beam, the remaining three steel plates are cut into many windows according to the design requirements to form a non-slanting rod. The vierendeel truss is equipped with walking platforms on the surface of the upper and lower horizontal trusses, and the crane operating mechanism and electrical equipment are installed inside the bridge frame. It has light weight and high overall rigidity. This is a type that is widely used in China.
 

Bridge cranes are widely used in indoor and outdoor warehouses, factories, docks and open storage yards. Bridge cranes can be divided into three types: ordinary bridge cranes, simple beam bridge cranes and special bridge cranes for metallurgy.
 

Ordinary bridge cranes are mainly driven by electricity, and are generally operated in the driver's cab, and there are also remote controls. The lifting capacity can reach 500 tons, and the span can reach 60 meters.
 

Simple girder bridge crane is also called girder crane. Its structure is similar to ordinary bridge crane, and its lifting capacity, span and working speed are small. The main girder of the bridge frame is a simple cross-section beam composed of I-beam or other section steel and plate steel. A chain hoist or electric hoist is used with a simple trolley as a lifting trolley. The trolley generally runs on the lower flange of the I-beam. The bridge frame can run along the track on the elevated or the track suspended under the elevated. This kind of crane is called a suspension beam crane.
 

Metallurgical bridge cranes can participate in specific process operations in the steel production process. Its basic structure is similar to ordinary bridge cranes, but special working mechanisms or devices are also installed on the lifting trolley.

 

 

The working characteristics of this kind of crane are frequent use, harsh conditions and high working level. There are five main types.
 

Foundry cranes: used for lifting molten iron into mixing furnaces, steelmaking furnaces, and lifting molten steel into continuous ingot casting equipment or ingot molds. The main trolley lifts the barrel, and the auxiliary trolley performs auxiliary work such as turning over the barrel. In order to expand the use range of the auxiliary hook and better serve the steelmaking process, the main and auxiliary hooks are respectively arranged in the main and auxiliary hooks with independent trolley operating mechanisms. on the auxiliary trolley, and run along their respective tracks. The commonly used structural forms are four-beam four-rail type and four-beam six-rail type.
 

 

Clamp crane: Use clamps to vertically lift the high-temperature steel ingot into the deep pit soaking furnace, or take it out and put it on the ingot truck.
 

 

Stripping Crane: It is used to force the steel ingot out of the steel ingot mold. There is a special stripping device on the trolley, and the stripping method depends on the shape of the ingot mould: some stripping cranes press the steel ingot with a neck bar, and lift the ingot mold with tongs; some use tongs to press the ingot mold, Small tongs lift the ingot.

 

Feeding crane: used to add charge to the open hearth. The lower end of the column of the main trolley is equipped with a pick rod, which is used to stir the material box and send it into the furnace. The main column can rotate around the vertical axis, and the pick rod can swing up and down and rotate. The auxiliary trolley is used for auxiliary operations such as furnace repair.
 

Forging crane: used to forge large workpieces in cooperation with hydraulic presses. A special turner is hung on the hook of the main trolley to support and turn over the workpiece; the auxiliary trolley is used to lift the workpiece.