Zelimir Ivelic

Približavanjem Hrvatske Europskoj uniji mijenja se sustav normi za ispitivanje kvalitete namjestaja, pa su hrvatske norme temeljene na starom svedskom sustavu zamijenjene europskima. Cilj rada je usporediti metode i rezultate ispitivanja elasticnosti i trajne deformacije ležaja-madraca prema staroj osnovnoj normi HRN D.E2.103: 1985 koja se poziva na normu za određivanje elasticnosti HRN D.E8.228: 1982 i novom hrvatskom normom HRN EN 1957: 2001. Rezultati istraživanja pokazuju da postoje znatne razlike između starog i novog sustava normi za ispitivanje kvalitete ležaja-madraca i da je vrlo tesko usporediti rezultate ispitivanja i elasticnih karakteristika. Istraživanja su pokazala da su trajne deformacije bitno manje pri ispitivanju po novim hrvatskim normama, te da rezultati ispitivanja izdržljivosti prema novoj hrvatskoj normi odgovaraju visokoj kvaliteti QII iz starih hrvatskih normi. Vrijednosti trajne deformacije su prema obje norme najvece kod modela GR-PESV.

U radu je opisana uloga normizacije u podrucju proizvodnje i ispitivanja kvalitete namjestaja te primjena normi za namjestaj u tom podrucju, te povijest europske i svjetske normizacije i razvoj metoda u podrucju ispitivanje kvalitete namjestaja. Prikazani su rezultati tehnickog odbora za namjestaj TO 136 i osnovne razlike u starom i novom sustavu normi. Usklađivanjem svojih laboratorija prema HRN EN ISO/IEC 17025:2000 rezultati ispitivanja, dobiveni u laboratorijima Sumarskog fakulteta bit ce priznati u najcjenjenijim europskim institutima koji su clanovi EURIFI-ja, pa ce na taj nacin biti potpora hrvatskim prerađivacima drva i proizvođacima namjestaja kako bi na sto bolji i prepoznatljiv nacin plasirali svoje proizvode na europsko tržiste.

Chairs are items of furniture that are in direct contact with the human body – sometimes even for many hours a day. This is why the ergonomic aspect is one of the most important factors in the design process of this piece of furniture. Moreover, it is to a greater or lesser degree connected with other features of the final product, such as: aesthetics, strength and rigidity, stability as well as the cost of materials and production. By reaching a good enough compromise between these features a numerical optimisation of a chair can be arrived at. In this paper mathematical descriptions of the above features are proposed with the aim of preparing an optimisation model of a chair. The decision variable box was formed by a set of selected furniture dimensions and the limiting conditions were to be realised indirectly by minimisation or maximisation of a goal function. The analysis of selected features as well as the expected result of the calculation leads to the conclusion that in order to achieve the best chair project from an ergonomic point of view, a polyoptimisation is required in which many features are considered simultaneously.

U radu je opisano stanje europskog i hrvatskog zakonodavstva u podrucju sigurnosti i kvalitete namjestaja. Analizirano je sto je do sada ucinjeno u približavanju hrvatskog zakonodavstva europskom sustavu i kako bi trebao izgledati novi sustav. Prikazani su rezultati tehnickog odbora za namjestaj TO 136 i osnovne razlike u starom i novom sustavu normi. Usklađivanjem svojih laboratorija prema HRN EN ISO/IEC 17025:2000 rezultati ispitivanja, dobiveni u laboratorijima Sumarskog fakulteta bit ce priznati u najcjenjenijim europskim institutima koji su clanovi EURIFI-ja, pa ce na taj nacin biti potpora hrvatskim prerađivacima drva i proizvođacima namjestaja kako bi na sto bolji i prepoznatljiv nacin plasirali svoje proizvode na europsko tržiste.

Construction and quality of the kids’ bedding-mattress has not been optimized yet i.e. adjusted to their users. This is evidenced by the data related to Sudden Infant Death Syndrome (SIDS) which the experts relate to poor construction of babies’ bedding-mattress and the fact that this complex and interdisciplinary area has not been fully elucidated. Majority of kids’ beddings-mattresses are the reduced versions of the beddings-mattresses for adults. This causes the biggest issues because various complications, such as gas poisoning (resulting from chemical processes involving the elements present in the bedding-mattress construction material), occur in the first months of infant’ s life. Levels of the gases blamed to cause cot death are too low to be harmful for adults, which is not the case with babies whose respiratory system is not fully developed. This does not mean that prolonged inhalation of hazardous gases generated from the poor quality bedding-mattress is not hazardous for the adults.

The subject of this paper is a research of child’ s cot quality during fatigue test and influence of dynamic loading on construction of child’ s cot. Research was not carried out before. The aim of an research was to determine the influence of acting force time on displacement of child’ s cot and wood species, and type of construction of children's cots on rigidity and durability during fatigue test. The modified European standard EN 716 was used in the research in such a way that a displacement, normally measured by the standard, was measured here. The research was carried out on three groups of samples consisting of six children’ s cots made of beech, pine and fir. The research results clearly show that the samples made of beech had greatest rigidity, the samples made of pine had middle rigidity while the samples made of fir had lowest rigidity. The research hypothesis that greater duration of loading will produce greater deformations of child’ s cot was not confirmed.