Coursework on modernization and calculation of a semi-knot crane

Contents

Introduction

1. Classification and justification of selection of the designed semi-goat crane

2. Purpose, description of structure and principle of operation of semi-goat crane

3. Calculation of basic parameters of the designed semi-goat crane

3.1. Calculation of crane movement mechanism

3.2. Calculation of load lifting mechanism

3.3. Calculation of tali movement mechanism

4. Safety precautions during operation of semi-roe crane

Conclusion

List of literature used

Introduction

In the problem of complex mechanization and automation of production processes, elimination of manual loading and unloading operations and elimination of heavy manual labor in the performance of basic and auxiliary technological operations, a significant role is assigned to lifting and transport engineering, which is tasked with the wide implementation in all areas of the national economy.

It is vital to increase the production of progressive means of mechanization of lifting, loading and unloading and warehousing. Modern in-line process and automated lines, inter-mill and intra-farm transport require the use of various types of lifting and transportation machines and mechanisms that ensure the continuity and rhythmicity of production processes. Therefore, lifting and transportation equipment has now become one of the main decisive factors in the efficiency of production.

The correct selection of lifting and transportation equipment affects normal operation and high production productivity. It is impossible to ensure its steady rhythm at the modern intensification stage without coordinated and trouble-free operation of modern means of mechanization of internal and inter-plant transportation of raw materials, semi-finished products and finished products at all stages of processing and storage.

Modern high-performance lifting machines operating at high speeds and having a high load capacity are the result of the gradual development of these machines over a long time. Back in ancient times, 4,000 years BC, ancient Chinese culture knew the use of the simplest lifting devices - levers and polyspasts used to lift water from wells and erect structures.

The pace of development of lifting and transportation machinery, the introduction of progressive machines and equipment and mechanization, the ongoing work to increase the technical level of the equipment produced have significantly increased labor productivity.

Specialized design organizations together with machine-building plants have created a number of high-performance, economical and user-friendly machines and devices for mechanizing loading and unloading operations. Electric and forklift trucks, various loading machines for piece and bulk cargoes, stacking and other lifting devices have been created, allowing for integrated mechanization in many areas of ferrous and non-ferrous metallurgy, machine building, coal, chemical industries, etc. Unique structures of heavy-duty floating cranes have been developed, new structures of general-purpose bridge electric cranes with a lifting capacity of 5 to 50 tons with high technical performance and much more have been created.

The main trends in the development of lifting and transport engineering are:

- creation of qualitatively new types of lifting and transportation machines and mechanisms, as well as extensive modernization of existing machines and installations to ensure mechanization and automation of loading, transportation and storage operations in all areas of the national economy;

- increase of lifting capacity and reliability of machines with simultaneous significant reduction of their metal consumption due to application of new kinematic schemes, more advanced calculation methods, use of rational lightweight profiles of rolled stock, new materials (alloyed steels, light alloys and plastics) as well as progressive technology of mechanical engineering (new methods of heat treatment, application of strengthening coatings, etc.). Note that reliability is a complex concept. It includes not only reliability and durability, but also others.

Also repairability and persistence, i.e. properties that determine the efficiency of using the equipment in the given operating conditions; increase of equipment productivity due to application of wide control of mechanism speeds, automatic and remote control using microprocessor and electronic computer equipment, for control of machine operation, and for calculation and design; creation of special gripping and other lifting units, as well as improvement of working conditions of crane operators thanks to the use of air cooling and cleaning plants in cabins and other measures.

Modern production of lifting and transportation machines is based on the creation of block structures that allow to obtain a high technical and economic effect in the manufacture and operation of these machines.

Classification and justification of selection of the designed semi-goat crane

Lifting machines, depending on the purpose, field of application and function performed, are classified into: lifting mechanisms, cranes, lifts and industrial robots.

The most common lifting machines are cranes - cyclical machines designed to lift and move in the space of the load held by the load-gripping device. They have a very diverse design and purpose.

They are divided according to design characteristic into:

- bridge cranes, which include the bridge cranes themselves, goat and semi-goat cranes, reloading bridges, wall movable and cantilever cranes, bridge cranes - stablers;

- boom type cranes - rotary cranes on the column, having a constant or variable departure; boom cranes with boom fixed on running gear frame or on rotary platform placed directly on running gear frame;

- tower, portal and semi-portal cranes, cable-stayed cranes, etc.

By the type of load-gripping device, cranes are divided into: hook, grab, magnetic, tick-borne, etc.

According to method of undercarriage resting on rail track, cranes may be of support type resting on track from above and of suspended type moving along lower rails of suspended crane track.

By type of drive, cranes are divided into cranes with manual and mechanical (electric, hydraulic, pneumatic) drives.

Crane mechanisms are divided according to operating modes: P - manual; L - light; C - medium; T - heavy; BT is very heavy.

On classes of use of mechanisms there are joint-stock companies, A1, A2÷A6 reflects intensity of use of the mechanism during its operation. According to the load classes of the mechanisms, B1-B4 reflect the relative load of the mechanism in accordance with the range of loads, and they depend on the purpose of the load coefficient .

Depending on combinations of a class of use and a class of loading the group of an operating mode of mechanisms is set: 1K÷8K.

In turn, goat cranes are divided into 3 main groups: general purpose (transshipment), construction and installation and special (for transshipment of containers).

Reloading cranes are made of two types: KKT and KK.

According to the type of lifting device, there are reloading cranes: with electric steel and with a freight trolley.

According to the load capacity, there are: KKT - with electric steel with a load capacity of 3.2 and 5t and KK - with a load trolley with a load capacity of 8; 12.5; 20 and 32t.

Gantry cranes, depending on specific operating conditions, are controlled: from the floor, from the cab and remotely.

Semi-goat crane is:

By design feature: semi-goat type crane, general purpose (reloading).

By type of crane load-gripping device: hook.

According to the method of supporting the undercarriage on the rail track: a support type crane .

By type of drive: crane with mechanical drive.

By type of transshipment cranes: KKT type.

According to the type of lifting device: with electric steel.

By carrying capacity: lifting capacity 5t.

By type of control: from the floor.

By the type of movement mechanism: with a separate drive.

Conclusion

During course design, a semi-goat crane was designed, with a carrying capacity of 5,000 kg, designed for use in the repair and mechanical or assembly workshop.

The crane movement mechanism was calculated, support wheels were selected and calculated, optimal wheel diameters and roller bearings were selected. Engines were selected and power calculated.

For the lifting mechanism, a rope of the LCR type of the structure with a diameter of dK = 15 mm with a breaking force of 174000 N. A drum was calculated. The electric motor was adopted and the main parameters were calculated. It will allow lifting loads weighing 5 tons. The electric steel gearbox was calculated and the actual load lifting speed was determined.

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