Skip lift

Contents

Introduction

Classification and justification of the design machine selection

Purpose, description of design and principle of operation of skip lift

Calculation of basic parameters

Safety precautions during machine operation

Conclusion

List of used literature

Application

Introduction

The process of any production is inextricably connected with the movement of a huge amount of cargo, from the supply of raw materials to the delivery of finished products. In the implementation of cargo flows at enterprises and the complex mechanization of labor processes, the main role is played by systems of lifting and transportation machines and equipment. For 1 ton of manufactured products in various industries it is required 10... 100 tons of raw materials, which are transported and stored by various complexes of lifting and transportation equipment. In flow and automated lines, the role of lifting and transportation machines has increased qualitatively, and they have become an organic part of technological equipment, and their impact on the technical and economic indicators of the enterprise has become very significant.

Lifting and transportation equipment developed in accordance with the needs of society and has a centuries-old history. Back in ancient times, people created simple devices for lifting and moving goods, primarily from the needs of agriculture (irrigation of drylands in many countries), construction and trade, where the transportation of a large number of cargoes was required.

Modern machines include the following basic principles: standardization, unification and block design. Technical and economic analysis establishes the most optimal types of machines and their parameters, determines the number of standard sizes of parts and assemblies, which allows to increase the quality of machines and the efficiency of their operation and repair.

In modern conditions of in-line and automated production, the importance of lifting and transportation machines has changed qualitatively. They went beyond their original purpose - auxiliary equipment for the mechanization of labor-intensive production processes - and are links in the process chain, ensuring the continuity of production, the main regulator of in-line production, the organic part of the technological processes that determine the rhythm and productivity of the main equipment of enterprises. PTM are the basis of complex mechanization and automation of production processes. Highly productive work of the whole enterprise depends on the right choice of the most rational machines.

The structures of lifting and transportation machines are constantly improving, and therefore new tasks arise in the calculation, design, research and selection of optimal parameters of machines that ensure high technical and economic performance and quality of machines.

Safety precautions during machine operation

The actuators of all mechanisms must have automatic brakes, and for each actuator of the lifting mechanisms it is mandatory to have two brakes - the main and the additional, acting independently of each other. The main brake must be installed either on the rib of the lifting mechanism drum or on the gear shaft. The additional brake can be installed anywhere in the kinematic chain of the lifting mechanism. The additional brake shall be operated with a deceleration in relation to the main brake. Each of the lifting mechanism brakes in case of operational load shall be calculated with a braking margin factor of at least 1.5. Lifting mechanisms shall have two independent limit switches. One of the limit switches shall interrupt the power supply circuit of the drive motor.

This switch shall be activated after the cargo suspension has passed the first switch in case of failure. The possible travel of the cargo suspension after the operation of the second switch is determined in accordance with the requirements of the rules for the construction and safe operation of lifting machines approved by the Gosgortekhnadzor of Russia. In case of actuation of the second limit switch, the load lifting mechanism shall be de-energized until the cause of failure of the first limit switch is determined.

Electric towers with remote control and a driven load-gripping device must have an alarm that registers the position of complete closure of the load-gripping element and the actuation of the blocking, which prevents its unauthorized opening.

In the case of multiple drives of the same mechanism, the short circuit or overload of one of the motors shall disconnect all motors of this drive from the power supply network.

The load-grabbing elements or devices shall be so designed that they securely fix and move the load and shall have locks preventing the spontaneous release of the load and/or preventing its release as a result of personnel error.

For load-gripping devices with steel ropes, the strength reserves for all ropes shall exceed the strength reserves corresponding to the rules for the construction and safe operation of lifting machines approved by the Gosgortekhnadzor of Russia.

Damaged removable load grippers identified during inspection shall be decommissioned.

Conclusion

During course design, a skip lift was designed, with a carrying capacity of 2 tons, designed for use in the repair and mechanical workshop.

For the lifting mechanism, the engine of the AIR160S4 GOST2833089 series was chosen, with a power of 15 kW and a shaft speed of 1500 min1, which will allow, when working together with the 2TsU315N50221UZ reduction gear, to lift loads weighing up to 2 tons. A cargo drum made of 55L steel was chosen with a compression strength of ο= 161.8 MP. A single-layer winding drum with a long threaded part of 522 mm and a number of working turns 29, two of which are spare.

According to the rupture force, a 6x19 LCR-type rope (1 + 6 + 6 + 6) + o.s. groups 1770 MPa as per GOST 268880 with diameter dk = 15 mm with breaking force Sp = 125500 N.