Ankle foot orthosis (AFO) stiffness affects ankle range of motion but can also provide energy storage and return to improve mobility. To perform multiple activities during the day, a person may want to change their AFO stiffness to meet their activity’s demand. Carrying multiple AFO and changing the AFO is inconvenient and could discourage users from engaging in multiple activities. This thesis developed a new quick-release mechanism (QRM) that allows users to easily change posterior strut elements to change AFO stiffness. The QRM attaches to the AFO and requires no tools to operate. The new QRM includes a quick-release key, weight-bearing pin, receptacle anchor, and immobilization pin. A prototype was modelled with SolidWorks and simulated with SolidWorks Simulation. The QRM was designed to have no mechanical failure during intense activities such as downhill walking and running. Unlike a solid screw connection, the QRM needed an additional part to eliminate unsecured motion related to clearance between the quick release key and receptacle anchor. Mechanical test results and measurement data demonstrated no deformation on each part after mechanical testing. User testing revealed that, although the quick release mechanism can be locked or unlocked rapidly, the person’s posture when operating can facilitate strut swapping. A learning effect occurred by repeated practice. The Quick Release AFO (QRAFO) prototype verified the manufacturing feasibility of the QRAFO design. Overall, the novel quick release AFO improved strut swapping time without sacrificing device strength.

The most basic property of a muscle is its ability to contract and produce force when stimulated. A muscle is mainly composed of cells consisting of myofibrils with its basic unit called as a sarcomere. A sarcomere is composed of actin and myosin responsible for the muscle contraction. The Hill-type muscle model is the most commonly used model to simulate the behavior of a muscle. A muscle can produce its maximum force at isometric conditions. The level of force produced in the muscle is determined by the the frequency of the signals from the CNS. The force production is also a function of force-muscle current velocity and force-muscle current length relations. A muscle contains two types of sensors / i.e. muscle spindle and golgi tendon organ, which give rise to the feedback control of the muscle length and muscle contraction velocity. In this study a 1-D model of a muscle is formed step by step in Simulink. In the models the muscle mechanics has been investigated and the results are compared with the previous works.

This report revolves around a project for Boliden which is a thesis work for a master in engineering within industrial design engineering. This project had a primary focus of developing a new mount for fire extinguishers that will be suspended on vehicles in Boliden's mines. The foundation of the project was an accident in Boliden's mine Aitik where a fire extinguisher exploded due to damages caused by the vehicle mount in combination with vibrations. The objective of the project is to identify the main problem with the vehicle mounts used today in Boliden's mines and solve it. The process used in this project is a fairly standard process that is separated into four phases; Context immersion, Ideation, Conceptual design and Final design. The last two stages focused on prototyping and testing to finalize the design, whereas the beginning of the process was trying to get a grasp of the problem. This included understanding the unique environment of the mines as well as getting to the bottom of the problem with the vehicle mount. Interviews and observations were conducted during a visit to Boliden's mine, Renström, in Skellefteå to investigate the problem. The conclusions from the Context immersion was that the main problem with the vehicle mounts was that they were not adapted for the mining conditions at all. A large number of vibrations and a lack of vibration damping for the mount was the leading cause for the damages on the fire extinguisher. This caused the vehicle mount to fail and in the process also damage the fire extinguisher. The solution to this problem turned out to be a more robust product using a stronger material with higher damping to suspend the fire extinguisher. This made the vehicle mount cope with the vibrations in a better way. A quick release mechanism was also implemented that assists with the vibration durability as well as make the fire extinguisher easy and fast to release. The fast release, as well as the ease of use, makes the vehicle mount adapted for emergencies as well.  The durability and the use of the new vehicle mount were reassured by a vibration analysis made in NX 12, as well as a short usability test. / Den här rapporten behandlar ett projekt för Boliden vilket också är ett examensarbete inom civilingenjör teknisk design med inriktning mot produktutveckling. Projektet har fokuserats på att utveckla en ny fordonshållare för brandsläckare som kommer användas på fordon i Bolidens gruvor. Grunden för projektet var en olycka i Bolidens gruva Aitik där en brandsläckare exploderade då den hade blivit skadad av fordonshållaren samt vibrationer. Syftet med projektet är att identifiera den underliggande problemen som finns med fordonhållarna samt ta fram en bättre lösning. Processen som användes i det här projektet är baserad på en normal designprocess som består av fyra faser. De sista två faserna i processen fokuserade på att prototypa och testa för att färdigställa designen, medan början av processen försökte problemet förstås. Det innebar att gruvmiljön som är unik var tvungen att utforskas samt att gå till botten med problemet med hållarna. För att göra detta gjordes främst ett besök till Renströms gruvan i Skellefteå där intervjuer och observationer utfördes. I slutet av Kontextfasen fastställdes det att huvudproblemet var att hållaren inte var tillräckligt anpassad för gruvmiljön. Den stora mängden vibrationer från miljön i kombination med en brist av vibrations dämpning för hållaren var orsaken till att skador uppstår på brandsläckare. Lösningen på problemet var en ny hållare som var mer robust samt att materialet som används för att hålla brandsläckaren var starkare samt hade högre dämpningsgrad. Ett snabblås lösning var också implementerad som också bidrar till ökad vibrationstålighet, den gör också att brandsläckaren går snabbt och enkelt att ta loss i nödsituationer. Hållbarheten samt användbarheten säkerhetsställs genom en vibrationsanalys utförd i NX 12 samt ett kort användartest.