Original scientific paper The paper presents the issues with the dynamic analysis of mine elevators used with underground exploitation of raw materials. Dynamic occurrences are particularly emphasized with those elevators due to the fact that they are facilities with extreme heights (up to 2000 m) and lifting speeds (up to 20 m/s) using the steel ropes. It shows the forming path of a competent dynamic model for the analysis of such elevators. Basic parameters (stiffness and damping) are of variable magnitude during the lifting, so their values are defined through a combination of theoretical analysis and performed experiments at RTB mine elevators at the town of Bor (Serbia). Keywords: damping; dynamic model; experimental analysis; mine elevators; stiffness Teorijsko-eksperimentalna analiza dinamičkih karakteristika rudničkih liftovaIzvorni znanstveni članak U radu je prezentirana problematika dinamičke analize rudničkih liftova koji se koriste pri podzemnoj eksploataciji sirovina. Kod ovih postrojenja posebno su izražene dinamičke pojave, jer se radi o postrojenjima s ekstremnim visinama (do 2000 m) i brzinama dizanja (do 20 m/s) pomoću čeličnih užadi. Prikazan je postupak formiranja mjerodavnog dinamičkog modela za analizu ovakvih postrojenja. Osnovni parametri (krutost i prigušenje) su, u toku dizanja, promjenjive veličine i njihove vrijednosti su određene kombiniranjem teorijske analize i realiziranih eksperimenata na rudničkom liftu u RTB u Boru (Srbija).

Spur gears have a wide application in the machine-building industry. Machining process primarily selected for these gears is hobbing method with modular hobs, or with Fellows cutters. Other methods which can be applied are profiling using the pull broaches, while the finishing can be done by gear shaving or grinding by the Maag, Niles or Reishauer methods. Moreover, in small (or unit) production, they may be formed using disc-or finger-type modular cutters. The article presents a method for cutting spur gears using a disc-type mill with a variable cutting plate profile. The influence of the number of blades of the presented milling cutter on the accuracy of the worked tooth profile was investigated.

Abstract. This article gives a detailed description of the development of an experimental sensor beam support with an integrated load cell, in this paper also named a smart support. The smart support is designed as a part of a beam bending experimental apparatus. For small universities, the financial effort needed to equip experimental mechanics labs is considered unjustified for the purpose of undergraduate mechanics classes. Thus the majority of experiments conducted in mechanics and similar classes are done during lectures as 5-minute presentations using available, inexpensive and simple apparatus. Such apparatus was produced in faculty workshops, by students as a part of undergraduate theses or projects with sponsoring companies. This article describes a process of building experiment apparatus through the student undergraduate theses and cooperation with local companies. It also shows the current state of beam bending apparatus at University North and the process of creating the initial design of a smart support. Some properties of two typical versions of load cells containing strain gauges were investigated using numerical simulations. According to load cell shapes, two different design solutions of smart support were proposed. The final chapter describes future plans to create data acquisition and ideas for developing further experimental modules or devices for various other experiments.