The purpose of a car jack is lifting the car and maintaining it at a certain height during different repairs. This paper focuses on the design of car jack, which belongs to the basic equipment of cars. Cars jacks are used mainly for changing tires and small repairs of a car. The aim of this paper was to create a parametric CAD model of a car jack and carry out numerical structural analysis of the car jack using the created parametric CAD model. The development of the parametric CAD model and structural analysis was performed using the CATIA V5 system. This paper describes the modern way of creating more complex mechanisms, which support quick modification of its parameters, and thus the entire design. The whole model of the car jack was parametrized. The stresses obtained by finite element method (FEM) analysis were confirmed with the analytical calculation in characteristic parts of the design, with some exceptions. At the end of the paper, an analysis of the obtained results was performed, on the basis of which specified conclusions were made.

Integrated intelligent CAD systems (IICAD) can be developed for different purposes. The objective of this article is to emphasize the advantages of the use of IICAD systems in comparison with the classic systems. The article shows a structure of one such developed system, namely the IICADv system. This system is used for automatization of activities undertaken during the realization of certain phases of the process of designing of shafts, especially the synthesis phase. The development of a module for computation of the shaft and integration of the entire system was performed in the C# programming language, while shaping of the shaft was performed in the CATIA system. The interlinking was performed thanks to previously modelled basic 3D models. In such way, utilizing the advanced IICADv system, the computation and shaping of the shaft is done almost instantly. The results of the use of the IICADv systems are generated final 3D models of the shaft, ready for use by numerous other applications.

This article presents architecture of integrated intelligent computer-aided design system for designing mechanical power-transmitting mechanisms (IICADkmps). The system has been developed in C# program environment with the aim of automatising the design process. This article presents a modern, automated approach to design. Developed kmps modules for calculation of geometrical and design characteristics of mechanical power-transmitting mechanisms are described. Three-dimensional geometrical parameter modelling of mechanical power-transmitting mechanisms was performed in the computer-aided design/computer-aided manufacturing/computer-aided engineering system CATIA V5. The connection between kmps calculation modules and CATIA V5 modelling system was established through initial three-dimensional models – templates. The outputs from the developed IICADkmps system generated final three-dimensional virtual models of mechanical power-transmitting mechanisms. Testing of the developed IICADkmps system was performed on friction, belt, cogged (spur and bevel gears) and chain transmitting mechanisms. Also, connection of the developed IICADkmps system with a device for rapid prototyping and computer numerical control machines was made for the purpose of additional testing and verification of practical use. Physical prototypes of designed characteristic elements of mechanical power-transmitting mechanisms were manufactured. The selected test three-dimensional virtual prototypes, obtained as an output from the developed IICADkmps system, were manufactured on the device for rapid prototyping (three-dimensional colour printer Spectrum Z510) and computer numerical control machines. Finally, at the end of the article, conclusions and suggested possible directions of further research, based on theoretical and practical research results, are presented.

Research activities in the field of modern Biomedical engineering show a more intense trend towards the use of sophisticated engineering measurement tools in order to optimize existing medical devices. External fixators are such an example of the above mentioned. Critical design parameters are being optimized by the use of existing engineering research methodology. One of the most important parameter for external fixators that have to be tracked are the interfragmentary displacements between the proximal and distal bone segment. This is usually achieved by the use of a finite element method. Another way is the use of displacement sensors or transducers. To verify these numerical results and to gain additional real life footage of interfragmentary displacements during testing, the use of a high speed camera has been taken into consideration. This paper compares previously acquired numerical data for a specific external fixator design parallel to the same setup whilst being recorded with a high speed camera. Results indicate good superposition with previously obtained data.

This paper presents the results of an experimental method for determining the efficiency of worm gears. Research into worm gears is primarily aimed at increasing the load carrying capacity, prolongation of life cycle and/or achieving higher efficiency, which can result in a reduction in exploitation costs. A larger share of sliding movement with respect to sliding-rolling movement of gearing contributes to the quiet operation but, on the other hand, causes a significant power loss. Very often, the load limit is not put by the load carrying capacity of gearing but by the ability to carry away the heat caused by friction. In order to design a worm gearbox that would be closer to the optimal solution from the temperature point of view (the heat), it is necessary to determine the operation losses. Besides the geometry of gearing, which influences the efficiency by forming conditions required for the creation of hydrodynamic lubrication, the applied lubricant also plays a significant role. In the research presented in this paper, mineral and synthetic oils were used for the combination of materials CuSn12/16MnCr5 used for gears operating at variable output load and two different rotational speeds.

In this paper simulation model which enables quick analysis of elastic rotor natural frequency modes is developed using Matlab. This simulation model enables users to get dependency diagram of natural frequency in relation to diameter and length of the rotor,density of the material or modulus of elasticity. Testing of the model is done using numerical analysis in SolidWorks software.

In mechanical technique, transmission means appliance which is used as intermediary mechanism between driving machine (e.g. of engine) and working (consumed) machine. The role of transmission is transmitting of mechanical energy from main shaft of driving machine to main shaft of working machine. The selection of transmission is limited by the price of complete appliance, by working environment, by dimensions of the appliance, technical regulations, etc. In mechanical engineering, so as in technique generally, mechanical transmissions are broadly used. Mechanical transmissions are mechanisms which are used for mechanical energy transmitting with the change of angle speed and appropriate change of forces and rotary torques. According to the type of transmitting, mechanical transmissions could be divided into: transmissions gear (sprocket pair), belt transmissions (belt pulleys and belt), friction transmissions (friction wheels) and chain transmissions (chain pulleys and chain). (Repcic & Muminovic, 2007)