LOCAL overhead crane and hoist manufacturer Condra is adept at delivering optimal solutions for their customers. Their engineering expertise, along with the flexibility offered by their in-house design facilities and wide range of standard products, has placed them among the world’s leading crane manufacturers.
Double bogeys on overhead crane save the day
Fitting double bogeys to the end-carriages of an overhead crane for a customer in Johannesburg, represented the key to the puzzle: how to meet customer specifications while still being able to install the completed crane in a factory with no roof access and limited headroom.
Usually, installation of a crane of this type involves lifting the disconnected end-carriages onto the gantry first, then attaching the girders to form the frame of the crane, and finally lowering the crab and hoist into position from above. In this case, however, there was not enough factory headroom to achieve that, even though Condra had designed the crane with a lowered profile to achieve maximum lifting height.
Condra’s solution was to fit both 12m-span steel girders with bogeys at each end, four in all, and develop a different installation sequence. Fitting the girders with bogeys freed up an additional 20mm of headroom through reduced wheel loading and smaller-diameter wheels on the end-carriages.
Integral bogeys also allowed placement of the girders on the factory gantry as the first step. Moving the girders apart, delivered space to allow lifting of the hoist into position between them, instead of lowering it into position from above. Closing up the girders, then linking and fixing their bogeys resulted in a completed crane with two double-bogey end-carriages. The installation was carried out at their customer’s factory.
Solution for hoist with unusually large rope drum
An unusually large rope drum on a hoist nearing completion at Condra’s Germiston factory, has been designed to hold and manage nearly 700m of rope, winding and unwinding it at high speed during very high lifts of 150m within a narrower-than-normal mineshaft.
Careful calculation of rope drum dimensions and winding sequence was the focus of the drum’s design. Drum PCD (pitch-circle-diameter) is 1 600mm and a 4:2 centre-lift reeving arrangement will avoid snagging the mineshaft sides.
The drum will carry 676m of 18mm rope, lifting and lowering loads at 30 m per minute, which is almost ten times faster than lifts in standard overhead crane workshop applications.
These are just some of the many engineering solutions that Condra has assisted their customers with. To learn more visit: www.condra.co.za
