International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

Overhead cranes are used in production halls, industrial buildings, transshipment yards, automobile factories, as well as in agricultural warehouses. The end carriage is an essential part of any overhead crane. Special attention is focused on the end carriage beam, which is a fundamental component of the end carriage in terms of load and strength. The introductory part of the paper aims to introduce the crane issues, particularly with respect to bridge cranes. The paper attends to the design of the end carriage beam for a single girder bridge crane with a 500 kg load carrying capacity including a strength analysis of the proposed beam. On the basis of the input load data of the end carriage beam and dimensions of area on which the main girder is placed on the end carriage beam, the minimum section modulus in bending was determined through the Allowable Stress Method as a critical parameter for the selection of the end carriage beam. The calculated value of the minimum section modulus in bending is 1416.18 mm3, based on which the U4O beam profile of S235 JR material was selected. One of the objectives is to create a 3D CAD model of the proposed end carriage beam and subsequently perform FEM analysis of the beam using Ansys engineering simulation software. The purpose of the analysis is to determine the maximum bending stress and maximum deflection of the end carriage beam. The results of the FEA analysis demonstrate that the proposed beam is satisfactory in terms of allowable stress and deflection. Moreover, the beam designed in this manner along with the numerical simulation results provides a precondition of its possible future production.

Forests tractors are inseparable part of a forest economy. Forests tractors serve for logging of logs in forests. Current forests tractors are usually equipped by hydraulic arms, which allow to expand the utility of a tractor. A tractor with a hydraulic arm is able to handle with wood logs without a need additional forest machine, which helps to reduce costs. On the other hand, it is necessary to analyse tractors abilities, which has such an additional equipment. This article is focused on assessment of stability of a forest tractor, which is equipped by such a hydraulic arm. It is a newly designed forest tractor which smaller dimensions, which is intended to be used in conditions with requirements for lower contact pressure and better manoeuvrability. As the hydraulic arm changes the centre of gravity of an entire tractor, mainly with the load, safe operation of the tractor needs to know limit conditions of stability under the maximal load and in the given slope inclination.

The paper is a continuation of research dealing with the structural design of the manipulator of the bulk material rotary valve based on the specifications of a food company. This issue is currently immensely topical for reasons such as increasing safety, speed, or efficiency of work. In the previous publication, the authors focused on determining the position of the center of gravity of the rotary valve due to the fact that this essential data is not provided by its manufacturer. Accordingly, the present work attends to the design of the steel structure of the trolley and the path along which the trolley in conjunction with rotary valve will move. The structural design is analyzed in the paper by means of analytical functional and dimensional calculations. On the basis of the parameters of the calculated centers of gravity of the individual components of the structure, the reactions from the track on which trolley travels to the weight transmitted by the prismatic wheels of the trolley were determined. The loads were calculated in transverse and longitudinal directions. In addition, reactions from the individual wheels were determined for the case, when the rotor valve is in a position with the rotor retracted (operating position). The achieved results demonstrate that the least favorable case for the stresses on the track travel of trolley occurs in the case with the rotor retracted. Furthermore, the calculation of the loads acting on the track beam in the most unfavorable position of the trolley was performed. Moreover, the resistive forces acting on the trolley were analyzed. The results indicate that the use of this mechanism will be feasible in operation.