Johannesburg-based cranes and hoists manufacturer Condra Cranes has received an order to not only design and manufacture a 70-t double-girder electric overhead travelling crane, but also erect the gantry and, thereafter, deliver, install and commission the crane, Condra MD Marc Kleiner says.
The initial three-dimensional site scan during the tender phase provided Condra with an edge, as it enabled the company to work from plans accurate to 1 mm in 50 000 mm, allowing for the design of a cost-effective gantry.
The manufacturer’s new 70 t crane will be a large machine with comparatively nimble operating speeds. Cross-travel speeds of up to 12.5 m per minute will be possible, with 25 m per minute achieved on the long travel.
The main hoist will have a lifting height of 9 m and the auxiliary hoist a lifting height of 10.73 m, with frequency drives delivering lifting speeds of 1.5 m per minute and 6 m per minute.
“An interesting decision taken during the design phase was to place increased focus on precise positioning. A frequency drive was incorporated in the main hoist to deliver absolute accuracy at very slow speeds. The auxiliary drive, which will do most of the fetching and carrying, will lift at a higher speed of 6 m per minute,” says Kleiner.
The delivery of the crane is scheduled for March, immediately after completion of gantry erection, he adds.
“After commissioning, the manufacturing company’s 21-m-span crane will be used to move and position injection-moulding heads. This order follows the delivery of three similar cranes over several years for various applications to the same customer. The reliability record and low maintenance costs of these machines, as well as rapid service response, had been key to Condra’s success in securing the latest order,” he highlights.
Condra manufactures locally and delivers parts anywhere in the country using an overnight courier.
“Machine uptime through robust design and readily available spare parts is a core philosophy for us. Robustness within the product range is achieved by designing to allow for operation beyond specified limits rather than designing as close as possible to them,” concludes Kleiner.