This thesis describes the optimization process for the pitchfork developed by the company Sverigegrepen. The work was done at the department of Applied Mechanics at Uppsala University. The project were handed by Ångström Materials Academy together with Sverigegrepen The work included a major prestudy of plastic construction, plastic materials, plastic injection and strength of materials. By applying the laws of beam theory, a mathematical expression could be provided, explaining the behaviour of the pitchforks teeth. By studying the pitchfork with tools such as 3D- CAD and FEA-simulations, an area where high concentrations of stress were found, an area known to have frequent issues with strength. From this data several concepts were created with an increased strength and a better distribution of stress. The plastic material was evaluated and tested to find the most valuable material characteristics. The provided information was used to isolate different functions in plastic materials, which is crucial for the pitchforks further functionality.

Följande examensarbete handlar om att ta fram konstruktionsförslag för en kopplingsmekanism som möjliggör delning av SverigeGrepens stallgrep. Produkten SverigeGrepen är med sin särskilda utformning och låga vikt ett ergonomiskt mockningsredskap. På grund av dess längd och form tillkommer en avgift för skrymmande paket vilket resulterar i en hög fraktkostnad. En lösning på detta problem är att skaftet delas itu, vilket tillåter produkten att fraktas i ett mindre paket. Vid ankomst hos kund monteras produkten med hjälp av kopplingsmekanismen. Lösningen ska innebära en minimal påverkan på egenskaper jämfört med hur produkten ser ut idag, som vikt och hållfasthet. För att erhålla ett teoretiskt underlag för problemet genomfördes en litteraturstudie. Denna behandlade områden som formsprutning och konstruktionsregler, finita elementmetoden, material, konceptval samt tidigare studier. Studien fortsatte med benchmarking och framställandet av en produktkravspecifikation. Dessa användes som grund för att generera olika koncept, där de mest lovande konstruerades i CAD. Metoder för konceptval applicerades, där slutligen två av koncepten valdes att kombineras inför en vidareutveckling. Resultatet av arbetet är ett konstruktionsförslag för en pluggliknande kopplingsmekanism som monteras på skaftets insida. Denna lösning har en låg vikt, klarar vardaglig belastning och tillåter montering av SverigeGrepens delade skaft. / This thesis aim is to develop a design proposal for a coupling mechanism for SverigeGrepen’s mucking tool which enables a splitting of its shaft and thus subsequently offer the ability to reliably mount them back together. SverigeGrepen is a lightweight product with a special design that makes it an ergonomic mucking tool. Due to the products length and shape a package fee is added in conjunction with its shipping which results in a high delivery cost. A proposal to solve this problem is a splitting of its shaft, which allows the product to be shipped in a smaller package. The product is assembled upon arrival at the customer. The solution should also have a minimal negative impact on SverigeGrepen’s existing product, such as its weight and strength. A literature study was conducted to obtain a theoretical basis. The study treated areas such as injection molding and rules for plastic design, as well as the finite element method, materials, concept selection and previous research. The study continued with market research and the development of a product requirement specification. These were used as a basis for generating product concepts, of which the most promising drafts were designed in CAD. Methods for concept selection were applied, where finally two of the concepts were chosen to be combined for further development. The result is a design proposal for a plug-like coupling mechanism that is mounted on the inside of the products shaft parts. The proposed solution offers a low total weight, endure the stress associated with everyday usage and allows the assembly of SverigeGrepen’s splitted shaft parts.