I.S.807-1963 Code of Practice for Design, Manufacture, 

Erection and Testing (Structural Portion) of Cranes and Hoists.

I.S. 3177-1965 Code of Practice for Design of overhead 

Traveling Cranes and Gantry cranes other than Steel Mill Cranes

I.S. 4137 Code of Practice for Design of Steel Mill Duty Cranes.

All cranes are basically fabricated out of standard rolled Steel sections and 

plates by using adequate size to suit the requirement. 

The entire structure can be divided into three main parts. I.T. Main Bridge, 

End carriages and Crab. In case of Gantry Cranes the Bridge Girders are fixed on 

the top of four gantry Legs which are connected to two under carriages. 

The salient features of above three parts are as under.

The main bridge Girders are fabricated from high quality steel plates 

forming a rectangular box section. To achieve 

the desired stiffness diaphragms are fitted at regular distance as per I.S. requirement.

 The girders are provided with the required camber so that 

the Girder deflection in full load condition will remain well within its allowable limit of 1/900. 

Internal surface of the box girder is free from corrosion as 

the box is welded and there is not contact with outside atmosphere. Maintenance

 - It is easy to carry out maintenance of the crane and clean it. Safety - 

The heavy box type structural construction of Double Girder Crane ensures safety and gives

 feeling of security to the worker while handling heavy loads and

 it also reduces chances of damage in transit.

The crab is a heart of entire Crane which carries Hoisting unit. Hence it is designed and manufactured with utmost care. 

The crab is manufactured from 

M.S. Plates and rolled steel sections. which is also provided with cross 

traverse wheel running on "L" type bearing housing assembly similar to that of 

L.T. wheel assembly. For heavy duty application, entire crab is fabricated out of M.S. Plate. 

The crab is carrying hoisting and cross Traverse unit 

with necessary brake assembly. Salient features of these are as under.

All the gear boxes which are used in Hoisting, L.T. and C.T. are horizontal shaft helical 

gear type with robust and sturdy M.S. fabricated housing. 

The entire gear assembly is running on anti friction bearing. 

The pinions which are used in the gearbox are integral and solid one piece pinion. 

The gear box housings are duly stress relived after the fabrication. 

the gearbox bearing sizes are machined on horizontal boring machine to ensure proper accuracy.

 All gears and pinions are duly hardened to with-stand the heavy loads for 

the life span depending upon the class of application. Provision is kept for 

the filling the lubricating oil with level indicator.

Rope drum is fabricated out of M.S. plate or made out of seamless pipe. 

The drum is accurately machined and grooved to accommodate the desired size of rope.

 The length of the drum is selected in such a way that the entire rope can be wound in one layer. As per I.S. requirement, 

when hook is at the lowest position,

 lead of the rope will have minimum tow fill turns on the drum.

 Similarly one spare groove for each lead shall be left when hook is in highest position.

For long travel arrangements following methods are used :

Center Drive Arrangement

In this system of long travel arrangement, long travel motion is availed through centrally located helical Gearbox. 

The power is transmitted through L.T. Shaft running on pedestal bearing and connected with the Gearbox, 

floating shaft and Universal joint assembly. The floating shaft is connected to the L.T. wheel and gear box by means of 

flexible geared coupling. The motor and gear box are connected by means of universal joint.

In this arrangement L.T. Drive system is provided at each end carriage by individual driving system. Both the drive comprises 

of a motor, gearbox, floating shaft and Universal joint assembly. The floating shaft is connected to the L.T. wheel and gear box