Konceptstudie kring snabb-fästen för skärutrustning till en motorsåg

Sammanfattning: This report describes a thesis project together with Husqvarna Group at the Advanced Development Handheld department. The aim of the project was to develop a prototype for a more efficient rapid bar exchange for one of Husqvarnas chainsaws. The reason for this is that the current design for changing the bar and chain is time consuming. The project faces several challenges in meeting necessary requirements for usability, structural strength, safety, manufacturing, design and functionality. The prototype was specifically designed to be compatible with Husqvarna´s top handle battery chainsaw, the T540 iXP. The first step in the project was to gather information about the problem and the components that relates to the problem. This was done by a feasibility study where knowledgeable personnel from different departments at Husqvarna was interviewed. The feasibility study conducted in a requirement specification. Early in the project it was clear that the problem had three subproblems:  1. Mount the bar to the clutch cover. 2. Mount the chain spur in the clutch cover. 3. Mount the module to the chainsaw. The next step in the process was to develop several potential solutions based on the various subproblems through simple schematic sketches. The concepts were evaluated using the previously defined requirements and with the assistance of knowledgeable personnel at Husqvarna.To solve the first problem, a solution was chosen where the bar is attached to the clutch cover using magnets. The second problem was solved through a solution involving a ball bearing. The concept that advanced for the concept selection in the third subproblem was a solution with a dog clutch mechanism.The selected concept was further developed to eventually produce a prototype. The final prototype included a dog clutch with angled “dogs” to facilitate easy module assembly. To attach the chain spur to the clutch cover, two ball bearing were implemented, which were press fitted into both the clutch cover and chain spur. Additionally, to attach the bar to the clutch cover, two magnets were incorporated into the front part of the clutch cover. The conclusions that can be drawn at the end of the project is that the final prototype is 2.96 times faster than the current solution. Additionally, the prototype provides Husqvarna with a solid foundation for further developing a rapid bar exchange.