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The field of research considered in this work is that of mechanisms generating inverse curves. We were motivated to approach this field, proposing variants of mechanisms based on Artobolevsky’s inversor, in blocking conditions, due to the lack of recent applications related to inversor mechanisms that draw curves other than straight lines. Based on Crawford’s inversor, Artobolevsky’s inversor is structurally and kinematically analysed in what follows. Hence, we carried out the kinematic analysis and simulation of four inversor mechanisms derived from Artobolevsky’s inversor, which draw different initial curves (a circle, a straight line, an ellipse and an Archimedes’ spiral) were performed. Inverse curves were generated under limited operating conditions due to geometrical dimensions and kinematic parameters. Given the researchers’ increasing interest in the development of applications related to inversor mechanisms (in fields such as: robotics, machine tools, visual arts and symbolic languages), as well as expanding databases of planar and spatial mechanisms, it is suggested that there is a need to create new mechanisms similar to those studied in this paper and to analyse their mode of operation.

Z namenom ugotovitve trdnostne analize oziroma časovnega poteka deformacijsko napetostnega stanja mehanizma instalacijskega odklopnika je v magistrskem delu predstavljena izdelava poenostavljenega geometrijskega-numeričnega modela mehanizma inštalacijskega odklopnika. Geometrijsko-numerični model mehanizma instalacijskega odklopnika je izdelan na osnovi metode končnih elementov iz geometrijskega modela enopolnega instalacijskega odklopnika tipa C z nazivnim tokom 25 A. Geometrijsko–numerični model omogoča simulacijo realnega časovnega poteka sestavnih delov mehanizma. S pomočjo modela se lahko oceni časovni potek deformacijsko-napetostnega stanja mehanizma in trenje med posameznimi deli. Določi se kritične dele mehanizma glede zagotavljanja funkcije delovanja in zdržljivosti ter možnosti optimiranja geometrije in materialov sestavnih delov mehanizma. S pomočjo posnetkov visokohitrostne kamere realnega časovnega poteka gibanja posameznih delov mehanizma instalacijskega odklopnika je bila izvedena tudi validacija delovanja geometrijsko-numeričnega modela mehanizma inštalacijskega odklopnika. Rezultati numerične simulacije časovnega poteka deformacijsko napetostnega stanja mehanizma instalacijskega odklopnika kažejo, da je izklopni mehanizem inštalacijskega odklopnika zasnovan tako, da omogoča dovolj hitro delovanje ne da bi prišlo do porušitve katerega izmed delov mehanizma. In order to determine the strength analysis or the time course of the deformation-stress state of the installation circuit breaker, the master's thesis presents the production of a simplified geometric-numerical model of the installation circuit breaker mechanism. The geometric-numerical model of the mechanism of the circuit breaker is made on the basis of the finite element method from the geometric model of a single-pole circuit-breaker of type C with a nominal current of 25 A. The geometric-numerical model enables simulation of the real time course of the components of the mechanism. Using the model, the time course of the deformation-stress state of the mechanism and the friction between the individual parts can be estimated. Critical parts of the mechanism will be determined in order to ensure its function and durability and the possibility of optimizing the geometry and materials of the components of the mechanism. With the help of high-speed camera recordings of real time course of motion of individual parts of the mechanism of the circuit breaker, the validation of the geometric-numerical model of the mechanism of the circuit breaker mechanism was also validated. The results of the numerical simulation of the time course of the deformation-stress state of the circuit breaker mechanism show that the shut-off mechanism of the circuit breaker is designed in such a way as to enable fast enough operation without breaking any of the parts of the mechanism.

Poškodbe zadnjih stegenskih mišic (ZSM) predstavljajo velik problem v sodobnem športu, njihova pojavnost in pogostost ponovitve je med najvišjimi v športih kot so nogomet, atletika, ameriški in avstralski nogomet ter ragbi. Eden izmed najučinkovitejših preventivnih ukrepov je ekscentrična vadba in znotraj nje najbolj uporabljena/proučevana nordijska vaja za ZSM (NHE), ki ima veliko pozitivnih in nekaj slabih lastnosti. Dve potencialni slabosti sta univerzalna zahtevnost vaje ter obremenitev v (pre)majhnih dolžinah mišično-tetivnega kompleksa ZSM. Namen te magistrske naloge je bil predstaviti prilagoditve pri NHE, ki bi omogočale individualizacijo in obremenitev ZSM pri daljših dolžinah ZSM. Glavni cilj je bil preveriti lastnosti različic vaje NHE, dobljenih prek spreminjanja naklona opore goleni ter ohranjanja različno velikega upogiba v kolku med izvedbo vaje, na 18-ih preiskovancih. Med meritvami je potekalo elektromiografsko in kinematično merjenje, podatki so bili statistično testirani z analizo variance za ponovljene meritve in parnim dvorepim post-hoc t-testom. Spreminjanje naklona opore goleni (0°, 20°, 40°) je preiskovancem omogočilo nadzorovano doseganje večjih oz. celotnih amplitud giba pri NHE ob enaki obremenitvi z vidika največjega neto kolenskega navora kot pri standardni NHE. Ohranjanje povečanega upogiba v kolčnem sklepu med izvedbo NHE (0°, 25°, 50°, 75°) je preiskovancem omogočilo doseganje večje obremenitve (z vidika največjega neto kolenskega navora), le-ta je bila dosežena ob večjih dolžinah mišično-tetivnega kompleksa ZSM. Rezultati tako kažejo, da je smiselno uporabiti predstavljene prilagoditve NHE v namen optimizacije kondicijskih, rehabilitacijskih in preventivnih vadbenih vsebin posameznika. Hamstring strain injuries are a major problem in modern sports. Their incidence and frequency of recurrence are among the highest in sports such as football, athletics, rugby, American and Australian football. One of the most effective preventive measures is eccentric strengthening, which includes the Nordic hamstring exercise (NHE), which has many positive and some negative characteristics. The two potential disadvantages are the universal difficulty of the exercise and the load in (too) short lengths of the hamstring muscle-tendon complex. The purpose of this master's thesis was to present adjustments of the NHE, which would allow for individualisation and loading of the hamstring at longer lengths. The main objective was to verify the characteristics of the variations of the NHE, obtained by altering the slope of the lower leg support and by maintaining a different hip flexion positions while performing the exercise, on a sample of 18 subjects. Electromyographic and kinematic measurements were performed during exercises and the data were statistically tested with the analysis of the variance for repeated measurements and the paired 2-tailed post-hoc t-test. Changing the slope of the lower leg support (0°, 20°, 40°) of the NHE enabled the subjects to perform in larger or even total amplitudes in controlled manner at the same maximum knee torque as for standard NHE. Increasing in hip flexion (0°, 25°, 50°, 75°) enabled the subjects to achieve greater maximum knee torque, which was achieved at longer lengths of the hamstring. The results show that it is reasonable to use the presented adjustments of the NHE in the context of optimising individual fitted training programs for general physical preparation, injury rehabilitation and prevention.

In gymnastics every exercise finishes with a landing. The quality of landing depends on subjective (e.g. biomechanical) and objective (e.g. mechanical characteristics of landing area) factors. The aim of our research was to determine which biomechanical (temporal, kinematic and dynamic) characteristics of landing best predict the quality of landing. Twelve male gymnasts performed a stretched forward and backward salto also with 1/2, 1/1 and 3/2 turns. Stepwise multiple regression extracted five predictors which explained 51.5% of landing quality variance. All predictors were defining asymmetries between legs (velocities, angles). To avoid asymmetric landings, gymnasts need to develop enough height they need higher angular momentum around the transverse and longitudinal axis and they need to better control angular velocity in the longitudinal axis.