Ditch jack OMA 541

Contents

Introduction

1 Jack Design Analysis

1.1 Classification of jacks

1.2 Characteristics and analysis of jack structures

2 Device , operation principle and technical characteristics

 OMA jack

2.1 Jack arrangement and operation principle

2.2 Technical characteristics of jack

3 Verification calculations

3.1 Calculation of hydraulic cylinder

3.2 Calculation of force created by handle on pump piston

3.3 Calculation of hydraulic cylinder pin for cut

4 Measures for technical operation of OMA jack

4.1 Main faults and methods of their rectification

4.2 Development of disassembly - assembly process

4.3 Stem Recovery Process

Conclusion

Bibliographic list

Introduction

The car is one of the most striking symbols of our current and tomorrow life. Millions of people work in the automotive industry, and if you add to them other millions whose work is related to the repair and maintenance of cars, it seems that very few human activities involve as many people.

The development of the maintenance system in the country, accompanied by the intensive growth of the fleet of personal cars, led to the need to introduce progressive forms and methods of organization and technology for servicing and repairing cars, the creation of new modern equipment and special tools.

Lifts are increasingly used in maintenance stations as basic equipment in the organization of various work stations of the main production areas.

One of the main advantages of lifts is that they allow you to more optimally organize the technological process of maintenance and repair of cars. In addition, the vast majority of lifts make it relatively easy to change their place of installation, which is very important under modern continuously changing production conditions.

Currently, a large number of lifts of various designs and applications are produced worldwide. Suffice it to say that in Germany alone, elevators are produced by 24 companies, in England, 16 with some of these firms producing 10 or more types and their modifications.

Jack Design Analysis

Jacks Classification

Jacks are designed to lift loads to a small height or to create the necessary compressive and tensile forces in mechanical devices, in prestressed building structures or for other technical purposes. There are a large number of different jack designs.

Jacks can be subdivided:

according to the principle of action: mechanical, hydraulic, pneumatic;

by type of working member drive: with manual, foot, pneumatic and electric drive;

in the field of application: road and garage;

according to the kinematic scheme of the transmission mechanism: lever, rod, rack, screw, parallelogram;

by gear type: gear, worm, chain, etc.

1.2 Characteristics and analysis of jack structures

The widespread use of jacks in ATP and STOA is due to two main reasons:

The first - jacks ensure secondary maintenance and maintenance of loaded car at emergency return from the line, when it is not advisable to perform loading and unloading operations.

The second is the possibility of carrying out separate maintenance and maintenance work on the open site of ATP or STOA at occupied stationary posts, as well as during a small amount of work.

Mechanical jacks (lever, rod, rack, screw and parallelogram) use a kinematic pair of screw-nut.

Many modifications have a lever kinematic scheme. However, in almost all jacks of this type, a parallelogram is used. Disadvantage of this design is non-uniformity of applied load and at certain moments of load lifting extreme loads occur in the drive.

Mechanical jacks are mainly used in car repairs in road conditions.

Hydraulic jacks - the most widely used nowadays, can have a manual or foot, pneumatic or electric drive. Hydraulic jacks, unlike other design types, are characterized by large dimensions and weight, but are much more lifting, have high reliability and safety.

According to the kinematic scheme, hydraulic jacks are divided into lever, stem, telescopic. Hydraulic jacks with a lever kinematic scheme, despite the drawback mentioned above, have an important advantage - a minimum pick-up height in a free position, which allows them to be applied to almost all types of car (with different ground clearance). An example of such a design is the domestic jack of the P304 model, which has a lever mechanism in the form of a hinged parallelogram that forms a lifting boom. The rod of the hydraulic cylinder and boom carry a grip to rest against the car.

The modern level of production allows the production of telescopic jacks with reliable gland seals (P308, P-310), which gradually displace the lever ones.

Hydraulic jacks with pneumatic drive can use multipliers consisting of two cylinders rigidly connected to each other (P 315). Axle with rollers, which serve for movement of jacks, is fixed on side of multiplier. The principle of operation of jacks consists in the following: compressed air is supplied through the control valve to the pneumatic cylinder of the multiplier, the piston of which moves, while the piston of the working hydraulic cylinder rigidly connected to it pumps liquid to the power hydraulic cylinder of the jack, and the latter lifts the load. The use of a multiplier greatly facilitates the control of the jack.

In addition to the above-mentioned domestic hydraulic jacks, hydraulic jacks of AFIT (Hungary) company with a carrying capacity of 750-2000 kg have been widely used in our country.

In these jacks, lifting is carried out using a lever mechanism with another drive. Jacks move using 4 wheels (rear self-aligning). In order to reduce the lifting time, the jacks are equipped with a mechanical fast approach device.

Pneumatic jacks, due to their constructive simplicity and ease of use, are becoming increasingly common abroad and in our country, they are produced by various companies in the USA, England, Germany, France. The advantages of pneumatic jacks are as follows: the compressed air used in them is available in almost all car farms; these devices are reliable for use in the conditions of raised the fire and взрывоопасное™; pneumatic jacks with lifting capacity 1... 2.5 tons have a weight of about 20 kg, i.e. have a low metal consumption.

The disadvantages of jacks of this type include the relatively low load capacity and the possibility of vibration of a raised car due to the fact that the working body is air, therefore, for safety of operation, pneumatic jacks are equipped with stops to block the rods.

Conclusion

As a result of the course project, an automobile scissor hydraulic jack was designed.

The general section described: classification, purpose and technical characteristics of the car jack; device and operating principle of the designed jack.

The design section made a power calculation of the jack, where the length of the hydraulic cylinder Lz = 323 mm, the diameter of the hydraulic cylinder D = 40 mm, the diameter of the rod d = 20 mm, the wall thickness of the hydraulic cylinder S = 2 mm, the thickness of the flat bottom S = 3 mm were calculated. The pin of the hydraulic cylinder was also calculated.

The process section covers installation and preparation of the jack for operation; general maintenance information. The diagram of hydraulic cylinder disassembly and recovery of jack hydraulic cylinder rod is given.