Since the beginning of the last century, many studies have been performed in order to improve our understanding on the milling process. Recently, Mishra and Rajamani (1992) applied the Discrete Element Method (DEM) to solve the milling problem. Since then, this method gained considerable success due to its ability to predict load motion and power draw by tumbling mills as affected by operating conditions. The application of this method at an industrial stage requires a more rigorous validation in order to produce realistic output. Lifter profiles play a key role in the performance of tumbling mills since they influence the motion of mill charge. Since lifters change profiles during their useful life due to wear, the performance of tumbling mills will correspondingly vary as a function of time. There is therefore a need to predict forces and wear on mill lifters in order not only to chose or design an initial lifter profile which optimizes tumbling mills performance over the lifters’ useful life but also to evaluate lifter replacement time and type and also modifications which can be performed on lifters and/or operating mill conditions in order to extend the lifters’ useful life. Despite the importance related to this subject, few works has been done in this field. In this thesis, we firstly assess the ability of the Discrete Element Method to model the tangential and normal forces exerted by the mill charge on lifters. Data from an experimental two-dimensional mill designed in order to record the normal and tangential forces exerted on an instrumented lifter were available. The measured results obtained at different speeds and percentages of filling have been compared to the Discrete Element Method simulated results in the same conditions. A good agreement has been found between the experimental and the simulated results in terms of toe, shoulder positions and amplitude of forces. After this validation of the DEM, we secondly assess the ability of this method to predict the wear of lifters in dry milling conditions. We derived a mathematical wear equation describing the removal of materials from lifters which takes into account all types of wear occurring in dry milling environment. We introduce a new approach to implement this equation in the DEM code in order to produce realistic simulated profiles. Our new method developed has been tested against laboratory and industrial data of evolving lifter profiles due to wear. Good agreement has been found between the simulated and the measured profiles. The variation of the load behaviour as a function of lifter wear in industrial tumbling mills studied was also investigated in this thesis. The objectives were to improve the understanding of the grinding process and quantify the variation of load behaviour as a function of lifter wear. Lifter modifications were also explored in order to extend lifters useful life. An attempt was also made in this thesis to derive, from the description of the load behaviour, equations in order to predict the wear of lifters without using the Discrete Element Method. Equations derived show the difficulty to use this approach. Success in this case was achieved only in a particular case where no significant changes occur in the load behaviour as a function of lifters wear. This finding confirms the DEM as the adequate tool to model forces and wear of tumbling mill lifters. The results obtained are of great economical significance since they can improve the profitability of mineral processing plants. A step forward in the use of the DEM not only to design milling equipments but also to improve the understanding, optimise and quantify the change occurring as a function of lifters wear was achieved.

With an aging population there is a growing need to assist people with disabilities. Particularly crucial is assisting people who cannot stand between positions necessary for everyday living, such as from a wheelchair to the toilet. It is unsafe to transfer people with direct manual techniques, thus a patient handling device is required. To reduce the burden on the healthcare system it is beneficial for disabled people to be cared for in-home. Many in-home caregivers may be physically impaired, thus patient handling devices for this use must require as little effort as possible. This thesis found that existing manual patient handling devices contained significant weaknesses when used for in-home care and there is potential to improve upon them. Expert interviews, computer modelling and physical models were used to develop a novel patient handling device which addresses these identified weaknesses. A reduction in the number of operator tasks, operation time and operation force was achieved. A method of supporting the patient solely by their upper body is required by the novel patient handling device, though an acceptable way of incorporating this has yet to be achieved. Testing of an upper body enclosure support revealed that a person may be supported by their lower thorax without substantial clamping or physical effort from the patient. Such a support has potential to be developed into an acceptable solution. Further development and testing in variable conditions encountered during practical patient handling is required.

Bakalauro baigiamojo darbo pirmojoje dalyje išanalizuoti krovininio 1,3 t galios keltuvo techniniai parametrai, darbo saugos lygis, nustatyta gamybos apimtis. Antroje darbo dalyje aprašyta gaminio paskirtis ir pradiniai duomenys. Atlikta krovininių keltuvų konstrukcijų variantų apţvalga – įvairių tipų krovininių keltuvų konstrukcijų sprendimų palyginimas. Pateiktas projektuojamojo krovininio keltuvo konstrukcijos aprašymas ir pagrindimas. Atlikti gaminio techniniai skaičiavimai (pagrindinių parametrų nustatymas, lyno ir pavaros skaičiavimas, lyno blokų ir tvirtinimo pirštų stiprumo skaičiavimas, lyno balansyrinės pakabos stiprumo skaičiavimas). Trečioje dalyje išanalizuota vienos detalės technologiniai maršrutai, nustatyti apdirbimo operacijoms reikalingi įrengimai. Atliktas uţlaidų, pjovimo rėţimų nustatymas bei techninis normavimas. Ketvirtojoje dalyje pateikiama techniniai ir eksploataciniai reikalavimai naudojant kėlimo įrenginį. Penktojoje dalyje atlikti ekonominiai skaičiavimai, kurių pagalba nustatyta ir pagrysta krovininio 1,3 t galios keltuvo savikaina. / The aim of the study is to design Cargo Lifter of 1,3 Ton Capacity. The first part of the bachelor‟s thesis analyses the main technical parameters of cargo lifter of 1,3 ton capacity, the level of labour safety and determines the scope of production. The second part describes the function of the product have been described, the versions of constructions of freight lifts have been reviewed, different construction solutions of various types of freight lifts have been compared in the second part. Description and justification of the construction of the designed freight lift has been provided, technical calculations of the product (definition of the main parameters, calculations of a rope and gear, calculation of strength of rope units and fastening pins, calculation of strength of a rope balance suspension) have been performed. The third part deals with the analysis of technological routes of a single part, determination of the installations necessary for processing operations as well as identification and technical rating of overlaps and cutting modes. In the fourth section presents the technical and operational requirements for using the lifting device. The fifth part deals with economic calculations on the basis of which the net cost of the freight lift of 1,3 t capacity has been determined and justified.

Today’s demand on forklift trucks performance and efficiency is high. The productivity is important but also the experience while handling the forklift. The handling has to be simple and genuine to make the driver feel confident and safe. To achieve high performance steering in articulated trucks, a hydraulic power system is often used.Simulation software are a powerful tool in development processes. The program gives the industry a possibility to develop, analyze and evaluate constructions and models more efficient.The purpose of this master thesis is to identify and increase the knowledge about the main challenges in the hydraulic steering system in an articulated forklift. The hydraulic system has been modelled in the simulation software Hopsan and validated against data from measurements performed on the forklift. The different challenges have been identified based on tests and the simulation results. For a deeper understanding of the system a literature study, mainly about the key components, has been done during the master thesis. A number of suggestions for improvement have been developed with focus on increasing the steering performance. The concepts and ideas have been evaluated and tested in the simulation model.The project resulted in a validated simulation model of the articulation and a number of suggested improvements on the hydraulic steering system.

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Under höstterminen 2013 har Stefan Erlandsson och Louise Andersson, designingenjörsstudenter på Högskolan i Skövde, utfört ett produktutvecklingsprojekt i samarbete med entreprenören Lars Willebrand. Målsättningen för projektet var att utveckla ett lyftverktyg som ska komplettera Willebrands produktserie bestående av; travers, svängkran, plåtbyrå och lyftverktyg. Lyftverktyget ska vara anpassat för att användas i kombination med en plåtbyrå, vilket innebär att det kommer användas till att lyfta material från höga och låga höjder. Lyftverktyget måste därmed konstrueras i syfte att underlätta för användaren och undvika arbetsskador som kan uppstå vid dessa lyft. Lyftverktyget ska även kunna anpassas till kunder som endast avser att lyfta skivformade produkter i midjehöjd. Projektet inleds med en förstudie där mycket fokus läggs på ergonomi och användaren. Förstudien har gjorts genom fördjupning i relevant litteratur, kontakt med industriföretag och genom att analysera konkurrerande lyftverktyg. Resultatet från förstudien har sammanfattats till en kravspecifikation som legat till grund för konceptframtagningen. Konceptframtagningen har skett stegvis, där lyftverktygets huvudfunktioner utvecklats var för sig. De funktioner som utvecklats är justering av sugkopparnas position, manövrering och lyft vid hög/låg höjd. Alternativa lösningar har tagits fram och utvärderats för att hitta den lämpligaste lösningen på varje enskild funktion. När de bästa lösningarna hade tagits fram sattes dessa samman till ett slutgiltigt koncept. Det slutgiltiga konceptet har analyserats och detaljutvecklats. För att underlätta tillverkning och tillgodose kundens behov har många av lyftverktygets delar anpassats och ritats om. För att säkerställa att lyftverktyget lever upp till kravspecifikationen har hållfasthetsberäkningar och en antropometrisk analys genomförts. Projektets process och resultat sammanfattades och diskuterades. Slutligen gavs förslag på rekommendationer för fortsatt utveckling av lyftverktyget. / During the second semester of 2013, product design engineering students Stefan Erlandsson and Louise Andersson have been involved in a project in cooperation with entrepreneur Lars Willebrand. The main objective of this project has been to develop a lifting tool for sheet materials. The lifting tool is one of four different products developed by Lars Willebrand. The line of products also includes an overhead crane, a slewing crane and a storage drawer for metal sheets, which are already fully developed and ready for production. The purpose of this lifting tool is to be used along with the storage drawer which means that is has to be optimised for lifting sheet materials from different heights. This means that the lifting tool has to be designed with regards to the users working postures. Human factors such as ergonomics have to be taken into account as well. The initial part of the project is a pre-study with focus on ergonomics and human factors. This pre-study included a study in relevant literature, contact with a manufacturing company and an analysis of the possible competitor’s lifting tools. The results from the pre-study have further been used to define the specification of requirements, which is the foundation for the concept development. The concept development has undergone a number of different phases. All of the lifting tool’s main functions were broken down and developed individually. The functions were as follows; adjustment of the suction cups, lifting from different heights and handling. The most suitable solution for each main function were chosen and assembled into one final concept. The final concept has been analysed and further developed in order to please the employer and the users of the lifting tool. Some details in the design have been changed in order to ease the manufacturing of the lifting tool. To ensure that the final concept matches the specification of requirements, strength calculations and FEM analysis have been made and anthropometrical measurements have been taken into account. The final chapters include a discussion and recommendations for further development of the lifting tool.