Low Headroom Bridge Crane Parametric Cad System

In this paper, with the task of research and development for overhead travelling crane parametric CAD system, with reference to present parametric CAD system, the technological developing clue of the project is provided according to characteristics of overhead travelling crane series, i.e. by means of classifying a engineering drawing into varieties of basic graphic elements and exerting parametric design on every element, the parametric design of the whole engineering drawing will be realized. The project takes AutoCAD launched by Autodesk Corporation as holding software, and develops secondly the applied software for the products. In order to determine the general frame of the software system, the method of modularization is adopted. In the system developed, the database form of intricate relative report is set up. A treatment mechanism is launched. It comprises 4 blocks, i.e. arithmetic formulary analyzer, intricate relationship analyzer, parameter reading analyzer and drawer, in which arithmetic formulary analysis and calculation of results are realized. It can also demand and analyze the intricate relative report of database, and refine data necessary from different reports, and perform drafting function. In the project, the second development is made from ActiveX Automation supported by AutoCAD. In Visual Basic applied program, visiting and controlling of objects in AutoCAD is carried out. At present, the function developed is only concerned about end carriage constructed drafting of overhead travelling crane. In practidal application, the parametric drafting of end carriage structure is realized with method mentioned above.