Structural and kinematic analysis of lifting and folding mechanism of mobile shutter
2019
Lucretia, P., National Inst. of Research-Development for Machines and Installations Designed to Agriculture and Food Industry, Bucharest (Romania) | Iulian, S.M., Etudes et Productions Schlumberger, Clamart (France) | Stefan, V. ., National Inst. of Research-Development for Machines and Installations Designed to Agriculture and Food Industry, Bucharest (Romania) | Ungureanu, L.-M., University Politehnica of Bucharest (Romania) | Dudici, L, University Politehnica of Bucharest (Romania)
The use of certain mechanisms in the construction of mobile platforms ensures that the products to be transported are loaded in the transport means without damaging them. This paper presents the structural and kinematic analysis of the lifting and folding mechanism of the mobile shutter of a commercial vehicle for transporting packed or containerised products. The structural analysis allows determining the structural groups (multipolar), which are the basis for realizing the mechanism for lifting and folding the shutter. The kinematic analysis consists in determining the kinematic parameters of all elements of the mechanism, the parameters underlying the kinetostatic calculation of the mechanism (determining the reactions in the kinematic couplings as well as the driving forces in the hydraulic cylinders). In order to highlight the kinematic parameters, the variation diagrams of the angular velocities and accelerations of the component elements were drawn. The kinematic analysis of the mechanism provides useful information regarding the lifting speed of the platform and, implicitly, the loaded material. A high-speed causes damage to the cargo loaded, and a small one causes a long loading time. The mathematical modelling of the mechanism was accomplished using Mathcad software. This mathematical modelling provides manufacturers with theoretical results that can be applied in practice for optimal sizing of the mechanism. The kinematic analysis made by simulation enables proper dimensioning of the elements of the mechanism, so that in the key positions the shutter is at the same level as the platform (in the maximum lifting position), or at the ground level, in the lower position, with the platform lowered for loading. This mechanism was actually used by INMA Bucharest to design and manufacture technological trailers for loading and transporting packed/containerised food products, trailers for transporting furniture, household appliances, and so on.
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