Mekaniskt brytjärn : Ett verktyg som ska underlätta vid manuell trädfällning

• Main Author: Tunåker, Peter
• Format: Others
• Language: Swedish
• Published: Umeå universitet, Institutionen för tillämpad fysik och elektronik 2015
• Subjects: Mechanics; Mechanically enhanced prying bar; Mechanisms; Mekanik; Mekaniskt brytjärn; Mekanismer
• Online Access: http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-109301

The purpose of the work resulting in this report is to develop a mechanically enhanced breaking bar, or prying bar, for bringing down trees. There was already a prototype to study, which was assembled by welded steel components. A specification of demands took form after continuous technical discussions with the inventor, assignee and mentors. When an analysis of this device and its function was made, the work continued with calculations to establish the foundation to design a mechanical model. Geometrical relationships were established to design the sub-components of the breaking bar and its functions. Simulations regarding material strength and mechanical function were made by the use of different modules in the CAD-software Solid Works and led to a simplified version of the breaking bar. The new simplified version was accepted by the inventor and the drawings for the new tool could now be made. During the time of this work the inventor has prepared his patent request and therefore this work has been classified and considered under secrecy for the inner circle persons containing the Kogertek-employees. The breaking bar which was produced with its powerful gear ratio is amplifying the force from the handle by a factor 25 and lifts 50 mm in the felling cut of the tree. In theory the tool would weigh approximately 1800 grams and can be used to bring down a tree with a diameter of at most 40 cm. Drawings for the constituent components were sent to a workshop to be manufactured and a mechanical breaking bar was assembled and tested.