Bridge crane Q = 16t.

Contents

Introduction

1 Description of bridge crane

2. Calculation of lifting mechanism

2.1 Selection of kinematic diagram of lifting mechanism

2.2 Selection of polyspast scheme and determination of maximum

tension of rope

2.3 Calculation and selection of steel ropes

2.4 Hook Selection

2.5 Calculation of hook thrust bearing

2.6 Calculation of suspension elements

2.7 Calculation of units

2.7.1 Calculation of geometric parameters of blocks

2.7.2 Calculation of unit bearings

2.8 Drum calculation

2.8.1 Calculation of main drum parameters

2.8.2 Drum strength calculation

2.8.3 Calculation of rope attachment unit to drum

2.8.4 Calculation of drum axis

2.8.5 Calculation of drum axle bearings

2.9 Engine selection

2.9.1 Determination of maximum static power

2.9.2 Selection of engine series

2.9.3 Selection of engine type

2.10 Gearbox and transmission selection

2.11 Calculation of drum shell connection

2.12 Selection of couplings

2.13 Brake selection

2.13.1 Selection of brake type

2.13.2 Determination of design braking torque

3. Mechanism of crane trolley movement

3.1 Determination of static loads on running wheels

2.2 Selection of wheels

3.3 Determination of crane trolley movement resistances

3.4 Selection of couplings

3.5 Loads in movement mechanisms during start-up and braking

3.6 Gearbox selection

4. Crane movement mechanism

4.1 Determination of static loads on running wheels

4.2 Selection of wheels

4.3 Determination of crane movement resistance

4.4 Selection of couplings

4.5 Loads in movement mechanisms during start-up and braking

4.6 Gearbox selection

Conclusion

List of used literature

Introduction

Modern high-performance lifting machines have high speeds and high carrying capacity, appeared in the aftermath of the constant improvement of machines in subordination for a long time. Back in ancient times, construction work was carried out related to the lifting and movement of large weights, for example, the construction of Egyptian pyramids (the Cheops pyramid 146.6 m high was built in the XXVIII century BC and composed of limestone blocks weighing up to 30 tons).

The first means of mechanization were levers, rollers they inclined planes, which can be considered prototypes of modern boom cranes, used to lift water in 30 centuries BC.

In the 7th century BC, blocks appeared, and in the 2nd century BC, gates with worm and manual gears.

In the Middle Ages, the development of lifting and transport equipment stopped. In the XI-XII centuries, in connection with the development of trade, navigation and the mining and metallurgical industry, the rapid development of lifting machines began. The first prototypes of modern cranes with manual drive and drive using topchak wheels appeared. At first, these cranes were made of wood, and only the axes and hooks were made of steel.

In the 20s of the XIX century, a steam engine was created, and in 1860 the first crane with a steam engine. In the 80s of the same century, cranes with an electric engine began to be used.

In the XVIII century, at the metallurgical plants of the Urals, Altai and Transbaikalia, a variety of lifting and transportation equipment was used for loading blast furnaces, rolling back cars, etc .

The beginning of domestic craning dates back to 1900, when cranes were first built at the Bryansk, Starokramatorsky and Putilov plants. In 1913, the annual production of cranes at the Bryansk and Starokramatorsky plants was 70 pieces.

In recent years, specialized design organizations, together with machine-building plants, have created a number of new high-performance, economical and user-friendly machines for mechanization of lifting, transportation and loading and unloading operations.

Electric and forklift trucks, various unloading machines for piece and bulk cargoes, as well as various stacking and other lifting means and elevators were created, which made it possible to carry out complex mechanization at many enterprises of ferrous and non-ferrous metallurgy, engineering, coal, chemical industry and other sectors of the national economy.

New structures of bridge electric cranes with a lifting capacity of 550 tons were also created, which significantly improved the technical and economic

indicators due to change of steel structures of cranes and application of progressive profiles of metal rolled stock.

Of the main structural trends in lifting and transport engineering, the following should be noted:

Creation of qualitatively new lifting machines and mechanisms, as well as extensive modernization of existing machines and installations to provide mechanization and automation of loading and unloading transport and warehouse operations.

Increasing lifting machines with a significant decrease in their weight due to the use of new kinematic schemes, more advanced calculation methods, new rational metal profiles, new materials - alloyed steels, light alloys.

Increased productivity for various types of equipment due to the application of wide control of the speeds of mechanisms, automatic, semi-automatic and remote control, special gripping and other lifting units, as well as the creation of improved working conditions of crane operators thanks to the use of air cooling and cleaning plants in cabins and other measures.

Modern production of lifting machines is based on the creation of block and unified structures (reduction gears, couplings, brakes), allowing to obtain the highest technical and economic effect in the manufacture and operation of these machines.

Description of bridge crane

The bridge crane consists of a bridge moving along above-ground rail tracks and a freight trolley moving along the bridge.

Among the structures of bridge cranes there are single-beam and double-beam bridge cranes, with a manual and electric drive, with a control cab and controlled from the floor (ground) or control panel.

Single-beam and double-beam cranes can be made support or suspended. The support crane moves along rails laid on metal or reinforced concrete crane beams; suspended - along the lower shelves of I-beams located on the floor by the lower belts of rafters. One-, two- and more span overhead cranes are used.

Depending on the type of load-gripping element, bridge cranes are divided into hook (with one, two or more hooks), magnetic, with a lifting electromagnet and grapple. In addition, there are bridge cranes equipped with special load-grabbing organs (ticks, paws, etc.).

Bridge cranes are made with flexible (on ropes) and rigid suspension of the load. With a rigid suspension of the load, metallurgical cranes are made for servicing the technological process in metallurgical production: cranes for stripping ingots (stripper), well cranes, cranes with legs (pratzenkans), multi-loading and other metallurgical cranes, the working member of which is rigidly connected to the trolley using a shaft and moves along vertical columns. Rigid suspension of cargo is also provided with cranes made on the basis of bridge and goat cranes.

Single-beam bridge cranes (crane-beams) consist of an I-beam, the ends of which are attached to end (transverse) beams equipped with running wheels. As a freight trolley, a manual or electric waist is used, moving along the lower belt of the beam. With large spans, the main beam is reinforced by trusses (vertical, horizontal).

Two-beam bridge cranes in the simplest case consist of two parallel beams attached at the ends to common end (transverse) beams. Freight trolley at double-beam cranes moves along rails laid along upper belts of main beams.

With large spans and loads, the crane bridge is made of lattice trusses or box beams. The bridge crane of the first type consists of two main trusses (vertical) directly receiving the load, two auxiliary (vertical) and four horizontal trusses, two of which are located in the plane of the upper belts of the main trusses and two in the plane of the lower belts. Each half of the bridge, consisting of four trusses, is attached to end two-wall beams. Bridge crane of the second type is made of two span beams of box section connected by end beams (also box section). Span and end beams are welded from sheet steel by manual and automatic welding. Diaphragms are installed inside to give them rigidity and stability. For ease of crane transportation and installation, end beams have one or two joints.

Rails for movement of crane bogie are installed on upper belts of span beams. Running wheels are mounted on end beams.

Bridge cranes are driven by electric motors installed on one of the galleries of the crane bridge. Crane movement mechanisms are provided with central or separate drives.

On bridge cranes, with the exception of single-beam (support and suspended) and double-beam suspended, for safe and convenient maintenance of electrical equipment and mechanisms located outside the cab, galleries and platforms with convenient exits and access to all crane mechanisms and electrical equipment shall be provided.

For this purpose, the crane bridge made of lattice trusses or box beams is equipped with two galleries (platforms). One of the galleries is designed to accommodate and maintain the crane movement mechanism, the second - to install and maintain trolley wires supplying power to the trolley. Both galleries are made along the entire path of the freight trolley: from one end beam to the other. On cranes in which the current supply to the crane trolley is carried out with a flexible cable, instead of a gallery, two platforms are usually arranged with an entrance to them from the end beams. The length of each platform for the convenience of servicing the bogie running wheels must be more than the base of the bogie.

Common elements of bridge crane structure

The structure of the bridge crane has a number of common mandatory elements, including: bridge bearing structure; winch lifting mechanism (winch, hoist, telfer, rack with drive and control lever) with one or two drums; gripping and hanging device (hook, grab, bracket, clamps).

The entire mechanism drives an electric drive, so it is usually called a bridge electric or crane-beam electric crane.

The most important characteristics of the device include its applications, type of drive, type of load-gripping mechanism, design features, operation mode, etc. Naturally, the price of a bridge crane will also depend on its complexity, size, multifunctionality and carrying capacity.

Design Features

The design features of each type of bridge cranes depend on the purpose of the beam crane and its operational requirements. The crane can have a mechanism that will move the entire platform on the trolley in a horizontal plane, and an auxiliary lifting mechanism (for example, an additional winch), as well as an emergency brake and buffer stops.

Scope of Application

Depending on the place of use and location, as well as the nature of the production tasks performed, the bridge crane can be construction, workshop, transport and deck.

For example, a shop crane beam is used for loading and unloading mechanization of large workshops, warehouses and industrial premises, covers the entire span of the workshop, serves its entire area and can move goods in any direction. Such a crane-beam consists usually of a bridge with a lifting mechanism and a moving trolley. The bridge moves along the upper crane rails of crane beams, and the trolley - along the lower rail mounted along the workshop. They can be equipped with a manual drive (if there is a small cargo flow in the shop or warehouse), but more often electric motors are used to lift and move the cargo, which are powered by current-conducting trolleys (busbar) and controlled by controllers from the cab on the bridge or bogie frame. Such crane beams serve a large cargo flow, have a carrying capacity of up to 5 tons, can be equipped with electric steel.

Type of cargo grip

All bridge electric cranes (beam crane) are equipped with load-gripping mechanisms of various types, shape and purpose - hooks, magnets, buckets, grapples, etc. According to the type of lifting and gripping mechanism, the crane is divided into hook, grab, foundry, magnetic and special.

Hook mechanism is equipped with 1-2 hooks for reloading piece weights. Bulk and liquid cargoes are transported in vessels or buckets.

Grapher - the mechanism is equipped with a bucket (grapher) instead of a hook. The ladle is opened with the help of drums mounted on the truck of the loader, and is designed for the movement of bulk loads and building materials.

Magnetic - equipped with a hook with an electromagnet on a controlled device, which is designed to transport products made of iron, cast iron and steel, as well as steel scrap and metal chips.

Magnetic grabber - has a magnet and ladle, which is very convenient and versatile.

Muld and Muldomagnetic - equipped with a special box for moving ground metal to melting furnaces (and an additional magnet for loading and transporting iron scrap).

Crane beam with paws (pratzenkran) - equipped with a grip in the form of paws, which are compressed, capture piece small loads - for example, steel rolled or rails. The mechanism uses a magnet that is turned on when the load is picked up.

If the crane is equipped with a cargo hook designed to perform bulk loading and unloading operations, then such a crane is referred to as general purpose bridge cranes.

Depending on the design of the bridge, bridge cranes are divided into single-beam and two-beam. Single-beam bridge consists of main beam connected to two end beams. Double-beam bridge has two main beams connected to two end beams.

According to the method of resting on the crane track, bridge cranes of the support and suspension type are distinguished. The support type bridge cranes include cranes supported by running wheels on a crane rail fixed on a crane beam installed on the columns of the workshop, racks. Bridge cranes of the underhand type with running wheels rest on the lower shelves of two-T beams suspended from the ceiling structures of the workshop.