DEFINING AND GEOMETRICAL MODELING OF A NEW FUNCTIONAL CHARACTERISTIC FOR BUCKET EXCAVATORS

Abstract

The purpose of this paper-work is the definition and mathematical modelling of the surface described by the contact area between bucket and arm, during operation. The metric characteristics of the coupling area result from the kinematics of excavator’s actuation mechanisms, however the surface described by the contact area becomes a functional feature by pairing the stress torsor of each point. The need to introduce this new functional feature is a direct consequence of the need to develop accessory coupling mechanisms on the machine arm. In the case of a coupling force generated through vacuum enclosures, the coupling area definition in the specified meaning, becomes essential for the adoption of this coupling mode, which is innovative in relation to the currently used mechanical or hydraulic couplings. Further, the authors deal with the geometric modelling of the contact surface between bucket and arm. This first step is necessary in the whole concept based on the kinematic study of the motion produced by actuating the three cylinders moving the excavator's arm. The shape and size of the contact zone are the result of modelling.