Σκοπός της παρούσας πτυχιακής εργασίας είναι η σχεδιομελέτη διάταξης ανύψωσης οχημάτων με δύο κολώνες και περιστρεφόμενα μπράτσα. Στα πλαίσια της εργασίας θα εκπονηθεί τρισδιάστατη σχεδίαση των εξαρτημάτων και της συναρμολογημένης διάταξης ανυψωτικού με χρήση κατάλληλου λογισμικού τρισδιάστατης σχεδίασης (3D-CAD). Θα παρατεθούν οι απαραίτητοι υπολογισμοί αντοχής για τα βασικά στοιχεία της διάταξης, με αριθμητικά αποτελέσματα. Με χρήση της μεθόδου των πεπερασμένων στοιχείων θα διεξαχθεί η μελέτη της στατικής αντοχής της σχεδιασμένης διάταξης με εύρεση των τάσεων και παραμορφώσεων (staticanalysis) που αναπτύσσονται για τα μέγιστα φορτία λειτουργίας, καθώς και υπολογισμός ιδιοσυχνοτήτων (modalanalysis).
The present Thesis deals with designing and calculating the strength of a two post car lift that will be used in a car workshop, with a lifting capability of 2.5t. The car lift consists of a fixed frame which has two vertical bolts of motion. The drive system consists of one power transmition belt, which transfers the power from AC motor in a bolt. The two Bolts are joined together by a closed kinetic chain with a gear ration 1:1 to rotate with the same speed and bearing nuts. The operation is as follows: The vehicle is placed on the feet and making use of the mechanism mentioned above, the nuts of the drive screws rotate on the bolts converting rotary motion to transport, lifting the car at the desired height. In the first chapter of our thesis we have an introduction on car lifts and especially two post car lifts. In the second chapter we talk about the purpose of this thesis. On the third chapter we make an historical flashback to car lifts, listed the types of deal and their characteristics. The fourth chapter concerns the theory of screws. This chapter describes the types of bolts, the sinuous line, the ranking of threading, the forces deployed in bolts and special reference is made to drive bolts that are used in our thesis. In the sixth chapter we design our construction (each part separately) and then we assembly them on solidworks. On our seventh and final chapter we calculate, using the Finite Element Method, the strength of our construction and we present our results.