content
- Introduction
- 1. The relevance of the theme developed.
- 2. Goals and objectives.
- 3. Rationale for the development of a magnetic brake.
- 4. Theoretical studies of the braking process.
- Conclusion
- References
Introduction
Diagram of the forces acting on the trolley.
Transportation of people is one of the critical processes for underground transport.
Physiological studies show that mobile foot in the mine workings in terms of energy equivalent to the energy cost in performing the work of moderate severity. Daylight in mine workings at a distance of 2 km of equal value in the working face of 30 minutes.
Pedestrian movement has a significant impact on the performance of the miners and in fact is a kind of work, requiring certain functions of the body as stress and production work.
Quality of the organization of transportation of people also has a significant impact on the level of occupational injuries [1].
"Safety Rules for coal and shale mines"
Requires mandatory carriage of people in the horizontal mine workings, if the distance to the bridge of more than 1 km, and inclined workings, if the difference is between the end points generation is more than 25 m [2].
To transport people in the mines used passenger trolley gruzolyudskie conveyors, monorail, passenger ropeways.
By means of transportation of people have been under high demands on safety and comfort of transportation of people ergonomic, aesthetic.
Of the above means of transport most people have long-term use passenger trucks.
Produced currently Krasnoluchskaya engineering plant passenger trolley for transporting people in inclined workings were established over 30 years ago and has since been subjected to a substantial upgrade not , although have some major drawbacks , the main of which is the need to use only certain way to lay the track . This is due to the design of the parachute equipment trolleys , interacting with elements of the track . Reduced requirements for a method of laying railway tracks in the workings for transporting people into the car can be achieved through the use of new principles of device parachutes , one of which is used as trapping devices permanent bodies parachute materials.
1. The relevance of the theme developed.
Currently in mines used a large number of trolleys for transportation of people inclined developments. These trolleys are designed to work with angles from 6 ° to 80 °. Braking devices do not always meet all safety requirements. As in trolleys in the sectional trains as shock absorbers use rope shock absorbers, which are characterized by rapid deterioration and unstable work.
Existing deficiencies in the operation, repair (restoration and working condition) parachute system installed on trolleys, such as the VLN and trains PSPN type does not satisfy all the conditions of safety and comfort when transporting people inclined developments led to the creation of new designs parachute system [3].
The disadvantages of these trolleys can be ignored if applied magnetic brakes (parachute device), in particular magnetic friction.
2. Goals and objectives.
The aim of this work is to develop a mine trolley for sectional inclined workings with an inclination of 30 ° to 6 ° with magnetic friction device [4].
To achieve this goal it is necessary to solve the following problems:
1) to develop the concept of section sectioned mine train with magnetic friction parachute device;
2) to carry out theoretical studies to determine the main force and kinematic parameters of the braking shaft human trolley with magnetic friction parachute device;
3) develop a design trolley (train PSPN) for transportation of people inclined developments.
3. Rationale for the development of a magnetic brake.
Abroad special trolleys for transportation of people inclined developments equipped with parachutes in the form of hard stops or safety hooks, trolleys and some of these stops are used only for the development of recovery time.
Safety devices of this type when braking deceleration caused by too much and create a danger of tipping trucks.
Trolleys , parachutes equipped with friction as the source of braking weight trolleys have limited scope and are not without serious drawbacks as the braking performance is dependent on the coefficient of friction between the working surfaces of the parachutes and rail tracks , which in turn varies for various reasons widely. The same shortcomings inherent friction parachutes constant pulling force on the brake pads ( with spring -hydraulic ) . Trolleys for inclined openings abroad typically manufactured with an open side of the seat with respect to the direction of movement to reduce the overall dimensions. This seating arrangement creates an unstable situation of people under braking and ensures safe carriage.
Widely used centrifugal speed regulators to ensure the inclusion of parachutes when speeding above normal. Centrifugal regulators apply the simplest parachutes (Thrust fork), and with more advanced (parachutes friction). Enabling parachutes centrifugal regulator has the advantage that its action does not depend on the degree of tension of the hoisting rope, which is especially important in case of accidents with hoisting winch brakes when spring drive on the trolley can not produce inclusion parachutes [5].
With a single drive device incorporating a parachute from a centrifugal regulator, catcher always work in heavy-duty, as if the rope will break when moving trolley up parachutes are included only after the truck starts to roll down and reaches a speed above normal.
Domestic parachutes also do not meet safety requirements. So , rope shock absorbers , which are assessed in the VLN type trolleys and trains sectional PSPN , although allow you to check the work of the parachute ( as they are reusable ), but they have several disadvantages . One of the bottom is the instability of his work : as the rope is made up of strands , each braking will be different from another different position relative to each other straight under braking breadcrumbs carriage . Also, the braking force depends on the state of lubrication of wires of the rope , which are different depending on when the rope is lubricated . Also disadvantage of this type of shock absorbers is their rapid wear . In addition , these types of parachute devices characterized by high labor intensity after removing the effects of emergencies and large dynamic loads during braking.
To eliminate these disadvantages and the idea of creating magnetic braking device, which can be either magnetic friction or electromagnetic friction [6].
Magnetic friction parachute devices include blocks collected on the basis of the permanent magnets and electromagnetic - electromagnets with auxiliary or external source of power. During braking units interact directly with the rail head due to magnetic forces of attraction.
4. Theoretical studies of the braking process.
Process of inhibition of human mine train with magnetic friction parachute device can be divided into five stages [7].
Stage 1. Starts with the breaking of the rope when the speed limiter is triggered or when manually switching parachute and ends with the activation of launchers springs magnetic friction parachute device.
Pic. 1 Diagram of the forces acting on the trolley, I step on.
Stage 2. Begins from the moment the drive springs parachute device and ends the moment the complete operation of the drive springs.
Pic. 2 Diagram of the forces acting on the trolley, II step on.
Stage 3. Starts with the complete operation of the starting and ending point of the springs start contact fist mounted on the chain loop, with the brake springs.
Pic. 3 Diagram of the forces acting on the trolley, III step on.
Stage 4. Starts with the initial contact fist installed on the whole circuit with the brake springs and ends with the moment when the brake blocks, left on a rail stop sliding on the surface of the rail head.
Pic. 4 Diagram of the forces acting on the trolley, IV step on.
Stage 5. Begins from the moment when released brake units cease to slide on rails and ends with the complete train stop.
Pic. 5 Diagram of the forces acting on the trolley, V step on.
Conclusion
Braking devices do not always meet all safety requirements. As in trolleys in the sectional trains as shock absorbers use rope shock absorbers, which are characterized by rapid deterioration and unstable work.
The aim of this work is to develop a mine trolley for sectional inclined workings with an inclination of 30 ° to 6 ° with magnetic friction device.
To achieve this goal it is necessary to solve the following problems:
- develop the concept of section sectioned mine train with magnetic friction parachute device;
- carry out theoretical studies to determine the main force and kinematic parameters of the braking shaft human trolley with magnetic friction parachute device;
- develop a design trolley (train PSPN) for transportation of people inclined developments.
The results of the theoretical research, for which performance requires the development program will establish the kinematic and force parameters of the braking device on which will be developed design magnetic friction brake.
References
- Статья: Шавлак В.Ф., боровлев С.В. «Шахтный и карьерный транспорт».
- Потапов М.Г., Спиваковский А.О. «Расчет и контруирование магнитных и электромагнитных приспособлений». М., Машиностроение 1986. 480 с.
- Севостьянов А.С., Герд Р.П «Шахтные вагонетки для перезки людей по горизонтальным и наклонным выработкам». М., Углетехиздат, 1986. 372 с.
- Гірничі машини для підземного видобування вугілля: Навч. посіб. для вузів/ П.А. Горбатов, Г.В. Петрушкін, М.М. Лисенко, С.В. Павленко, В.В. Косарев; Під заг. ред. П.А. Горбатова.– 2–ге вид. перероб. І доп. – Донецьк: Норд Комп'ютер, 2006. – 669с.:іл.
- Обладнання очисних вибоїв вугільних шахт/ Укл. В.П. Кондрахін, М.І. Стаднік, Г.В. Петрушкін, М.М. Лисенко. – Донецьк: ДонНТУ, 2008. – 90с.
- Выбор средств механизации очистных работ и определение рационального режима работы выемочного комбайна: (Учеб. Пособие по самостоятельной работе студентов специальности 090301 «Разработка месторождений полезных ископаемых» /Сост.: В.П. Кондрахин, Г.В, Петрушкин, Н.М.Лысенко. – Донецк: ДонНТУ, 2003.– 28 с.
- Методика оценки и классификация показателей разрушаемости угольных пластов основных бассейнов СССР. Часть II. Классификация показателей разрушаемости угольных пластов. – Москва: институт горного дела А.А.Скочинского, 1978 – 10с.