COMPUTER AIDED DESIGN, FABRICATION & INTERFACING OF E.O.T CRANE

COMPUTER AIDED DESIGN, FABRICATION & INTERFACING OF E.O.T CRANE

Abstract:

The project titled “COMPUTERIZED ELECTRIC OVERHEAD TRAVELLING CRANE” is being undertaken to counter difficulties in material handling and load lifting processes. In this paper we discuss the preparation of the program of Hoisting Mechanism in Visual Basic and the steps undertaken to complete the fabrication of the EOT crane and finally interfacing it with computer. The E.O.T crane model which is fabricated comprises of all the three mechanism namely Hoisting, Trolley Traveling and Bridge Traveling. The VB program designed comprises right from large database of material selection to the design suggestions provided at each steps taking into account the optimization. The fabrication involves selection of layout, material for individual components, motors etc and various considerations taken into account for fabrication. This is followed by interfacing the E.O.T. crane model with computer using relay circuit. As the name suggests it consists of Relays, Transistors, Diode, Optoisolators etc. The relay circuit is activated by parallel port LPT1 Data pins using C language.

Introduction:

The E.O.T consists essentially of a girder, or girders, supported at each end on trucks capable of traveling on elevated fixed tracks, and a trolley, equipped with hoisting and other mechanism, capable of traversing from end to end of such girder or girders. Such cranes vary in lifting capacity from about 2 tons to 400 tons, and in span from 20 ft. to 150 ft, or more. For capacities of 10 tons and upwards an independent auxiliary hoist rated at 1/5 to 1/3 that of the main hoist is frequently provided. The computer Aided Design facilitates gives alternative parameters and thus calculates the unknown parameter which speeds up the design process. In the computerization the scope for providing cabins fixed to bridge is eliminated thus reducing the cost and space.

Computer Aided Design of Electric Overhead Traveling Crane employs Visual Basic as the front end. In the design using V.B., the user will have to input, the Load to be lifted, the operating conditions as in nature of duty, service factors, hoisting speed and then the design of rope is done. The Design of rope is on the basis of life criteria and can be checked for strength criteria and vice versa based upon the data available. The diameter of rope is calculated and the thus the diameter of sheave is calculated. During calculation of rope diameter the tackle efficiency, fall system depending on load, lay of rope and thus various parameters are analyzed for selecting the diameter of rope. In the tackle assembly the moving sheave assembly and hook Assembly are calculated. In case of Moving sheave assembly the diameter of moving sheaves

and corresponding dimensions of sheave is calculated. Similarly the selection of bearings, dimensions of shackle plate and check plate are calculated. In case of hook assembly the bed diameter C is decided based on load and then the corresponding dimensions are generated by empirical relations and thus all the dimensions are obtained. Then failure analysis is carried at every part. For example when the tensile failure at the threaded part is carried out in case of failure the dimensions are rectified thus modifying the load and the overall dimensions. Thrust bearing design is followed and the bearing selection is completed. Finally the cross-piece design is carried out taking into account the various deign considerations. The hoisting mechanism is designed by selection of appropriate drive unit and rope drum.

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