Vol 60 Iss. 1

Leningrad Mining Institute together with “Kizelugol” Combine created an experimental frameless tractor for moving a train of cars on smooth horizontal and inclined rails. The tractor was manufactured in the central mechanical workshops of Kizelugol Combine and in the fall of 1967 it passed successful factory tests.

The modes of realization of the coefficient of adhesion of smooth driving wheels with rails have been studied in detail. It is established that at constant locomotive speed and constant pressure of driving wheels on rails there is a strict dependence between wheel slip and the coefficient of clutch.

Calculations of modern locomotives with smooth driving wheels are made separately for the conditions of operation in traction and braking modes at the highest loads, when slipping or skidding is especially likely. At train resistance or braking forces, adjacent to zero values, the gravity of the locomotive causes a very large reserve of traction forces, and in the study of these modes was not necessary. Obviously, therefore, it was assumed that the zone of elastic sliding passes through the origin of coordinates.

An experimental sample of a friction-driven hoist was created and successfully tested at LGI. The hoist is moved by a special traction device with smooth drive wheels on a vertical rail made of I-beam.

In the creation of efficient and economical vehicles for the mining industry, a significant place is given to traction devices that automatically adjust the pressure of the drive wheels on the rail depending on the realized traction force. One of the main advantages of these mechanisms is that the traction force in the interaction of the wheels with a smooth rail is created independently of the coupling weight of the self-propelled crew.

In LGI the principle scheme (figure) was developed and the working design of the experimental sample of self-propelled stand for Koelgine marble quarry was made.

Experimental studies of traction devices capable of being oriented relative to the input tip of the traction rail during movement are underway at LGI. They are intended to equip locomotives with mixed principle of operation, which are supposed to be used for mechanization of transport works on delivery of people, equipment and materials along horizontal and inclined rail tracks.

In order to ensure the optimal mode of operation under any conditions, traction devices with unstable transmission ratio are equipped with a relay tracking system, which operates on the deviation of the set angle and maintains the calculated value of the transmission ratio. It consists of a control object and an automatic regulator.

The Leningrad Mining Institute and the Telman Fine and Technical Fibers Combine were involved in the realization of the contract of creative work. In fulfillment of the agreement on creative cooperation Telman created suspended monorail tractors with automatic regulation of the drive wheel pressure on the rail depending on the train resistance or the required braking force.

Traction devices with automatic regulation of the pressure of wheels to the rail provide a given mode of adhesion of smooth wheels with rails regardless of the profile of the track and changes in external load, which allows them to be used to move loads in inclined mine workings with any inclination angles.

Traction devices with automatic regulation of the force pressure of traction wheels to the rail depending on the resistance to movement are considered in the works of V. S. Bersenev.

Studies of the application area of traction vehicles with automatic regulation of drive wheel pressure on the rail showed that mechanisms with elastic sliding can be used not only in the creation of vehicles (self-propelled skips and locomotives), but also in the design and construction of new friction drives for rotating parts of large units (cement kilns, mills, scrubbers, reactors, etc.).

At the experimental site of the trust “Chiaturmanganese” a brake bogie for automatic speed control of mine trains on steep downhill slopes was tested, in which for actuation of the mechanical braking system an articulated-lever drive mechanism is used, providing reliable adhesion of the drive rollers with the side surfaces of the rail.

The crank mechanism in a general form is unambiguously defined by three independent parameters, for example, the following...

В результате исследования тяговых устройств разработана новая, наиболее целесообразная конструкция периферического привода для сгу­стителей пульпы.

Plate conveyors in recent years are increasingly common at industrial enterprises in the USSR and abroad (FRG, Belgium, England, etc.) For example, in the mines of the Ruhr Basin they make up more than a third of the total number of underground conveyors (excluding downhole conveyors). In a number of cases, slat conveyors are the only acceptable means of continuous transportation of goods.

The traction devices created in LGI have one or two smooth drive wheels. Their number under the conditions of strength determines the possible traction force at given dimensions of the traction device.

The use of high-strength synthetic and rubber tether belts allowed to significantly increase the length and productivity of belt conveyors. The length of individual belt conveyors abroad reaches 4-5 km, and productivity 20000 t/h. There are projects of conveyors with two head drives with the length of 14 km.

When studying the executive organ of the rowing-rotor loading machine for recording the forces on the oscilloscope was made and applied rheostat sensor mounted on the indicator head of the clock type, which was attached to the dynamometer and recorded the change in the position of its spring.

At interaction of gripping bodies of loading machines with the stack of resistance forces of the latter to the introduction and separation of some volume of material are random, stochastic nature. This makes it difficult to determine the necessary driving forces on the actuator of loading machines. The existing methods of calculations touch upon the issues of interaction with the stack of the bucket actuator of the lower gripper and paired raking tines. The continuous acting actuator of the upper gripper is insufficiently investigated. The questions concerning principal features of this body and its energy parameters are touched upon only in a few works. To some extent, this is due to the uncertain nature of the motion of this organ when interacting with the stack, which makes it difficult to consider its kinematics, and hence the determination of forces in the links, not to mention the dynamics of loading...

Widely used and as the main mechanical means of hydraulic lifting systems hydro-elevators to a large extent exhausted their possibilities. Further constructive and technological improvement slightly changes their significant disadvantages: low efficiency, high energy consumption and low lifting height.

The main indicator of a mine loading machine is its technical productivity, which depends on many factors. These include, first of all, factors characterizing the machine itself and especially its actuator: the principle of impact on the stack, size, shape, number of cycles per unit of time. Substantial influence on productivity have external factors, which include physical and mechanical properties of the loaded material, the characteristics of the stack, the size of the excavation, the organization and type of transport following the machine.

Novikov gears due to their inherent increased load capacity are becoming more and more widespread. However, the issues of bearing durability, as well as the strength and stiffness of their shafts have not yet been studied. Therefore, the load of bearings and shafts is either not assessed at all or is assessed very roughly. This situation is explained by a certain specificity of force formation during the interaction of links in Novikov gear and the lack of proper developments due to the unexplored nature of the issue.

The task of structural studies of chamber feeders is to determine the most appropriate forms of parts and units of chambers, as well as the rational design of the feeder as a whole.

A device for large-scale graphic representation of wheel tooth profiles cut with rack and pinion tools using the running-in method has been developed. It uses a special template made of transparent sheet material (plexiglass), in which narrow slits are provided in scale in the shape of the cutting tool contour. On the lower plane of the template there are equally spaced parallel risks perpendicular to the risk coinciding with the middle dividing line of the rail.

When studying the input of material into the pulp conveyor chamber feeders used two possible design schemes: with gravity and hydrodynamic feeding of material. The most expedient design of chamber feeders are feeders with hydrodynamic feeding of material, as they more meet the conditions of operation of hydraulic conveying systems.

A simple graphical method of determining the shape factor of wheel teeth used in calculations of fracture strength of gears is developed. The properties of the tangent to the parabola, which fits into the contour of the tooth, are taken into account in determining the dangerous cross-section of the tooth, usually considered as a cantilever bar.

Gear pneumatic motors belong to volumetric type motors. The working chambers are the hollows, and the pistons are the teeth of the mating rotors. The troughs and teeth have complex shapes and participate in complex planar reciprocal motions, making it difficult to understand the working processes of these engines.

The task of creating a flotation machine that meets modern requirements can be solved only if the rational design of the main components and linking them into a single complex, subordinated to the fulfillment of the required technological and technical and economic performance of the machine.

During bench tests of Novikov gears to identify their load capacity it was possible to experimentally assess their efficiency. For this purpose, an electric motor balanced on support rollers was connected to a test bench with a closed power flow. By its angular deviation in the steady-state mode of operation was determined by the reactive torque of the motor, the power of which at the closed circuit of loading gears is spent only on overcoming the resistance to rotation.

For electronic modeling of working cycles of pneumatic machines a relay switching device (RSD) is developed and used. It serves for changes in switching of the electronic model when solving problems described by different systems of differential equations at separate intervals of variables change.

The choice of optimal parameters of gears with Novikov gearing is a responsible task in mining engineering, especially in the gears of underground machines, to the dimensions of which are strict requirements. Even greater difficulties arise when designing Novikov gears that would satisfy the requirements of high contact and fracture strength of teeth. Reliable information about the experimental application of these gears in mining engineering is still insufficient. Besides, the experimental data refer to separate gears made with different parameters, materials, initial contours. They are obtained under different load conditions. All this complicates orientation in the choice of optimal parameters of Novikov gears in the design of.

On the example of a vibrating loading machine the method of calculation of acting loads in kinematic pairs of the eccentric drive of the vibrating loading chute is developed. In this case the graphical method of kinetostatic study is used, by means of which the values and directions of reaction in the joints are determined.

Modern methods of calculation of pneumatic hammers are based on the assumption that their working processes are equilibrium, and the mass exchange at filling and emptying of the working cavities of the cylinder occurs in accordance with the regularities of the steady flow of compressed air.

Practical needs of approximation of scientific research to production dictate the necessity of studying natural objects in natural (industrial) conditions. This requires reversal of the classical vibration test bench-object scheme, i.e. not the object is installed on the test bench (often it is simply impossible), but the object itself is transformed into a full-scale research test bench by attaching to it a vibration device consisting of a vibration exciter and measuring systems.

Efficiency of pneumatic perforators, durability and reliability of their work are largely determined by lubrication of the rubbing parts. The studies carried out at the Pnevmatika plant have shown that under conditions of high dynamic loads, sliding speeds of contacting surfaces and increased temperatures in the contacts, lubrication significantly affects the parameters of the perforator, especially the torque, as well as the rate and nature of wear of the main rubbing parts.

Mine regulations of many countries contain requirements that single-rope hoists intended for the descent of workers must be equipped with lifting vessel parachutes. Existing parachutes, unfortunately, do not fulfill their main task, which is to fail-safe braking or stopping the falling stand (skip) in the case of breakage or detachment of the rope.

Created in the Leningrad Mining Institute, with the participation of the Research Institute of Polymerization Plastics, Okhta Chemical Plant and Donetsk Machine-Building Plant named after the XV-anniversary of the LKSMU, plastic brand PP-45 has found wide application as a lining of rope-driving pulleys of mine multi-rope hoisting machines.

In the present article with the help of the method of I. G. Bubnov - B. G. Galerkin an establishing (transitional to static) process of deformation of an elastic half-space from the applied to its surface instantaneously and further in time not changing, asymptotically decreasing from the center, axisymmetrically distributed normal load is considered - p.

The main question that .has to be solved in the design of any machine, is the question of the forces arising in the links of the machine during its operation. The cause of force loading in crushing machines is the resistance of the material to crushing. Theories of crushing are designed to answer this basic question or to quantify the energy intensity of crushing.

One of the complex processes in hydro-mines and coal preparation plants is water clarification. Volumes of water reuse in the technological process at hydraulic mines are estimated in thousands of cubic meters per hour and depend on the adopted technology of excavation, transport, lifting and coal preparation.