Sales of the mechanical drive range of Dodge motorised torque arms (MTAs), supplied by Southern African bearings and power-transmission products distributor Bearings International, have steadily increased over the past two years, as the product has been tried and tested in the local market, says the company's bearings manager Ross Trevelyan.

The MTA range was initially available in sizes 2, 4 and 6 and, as of September 1, has been complemented with sizes 3, 5, 7 and 8, which has provided customers with a full range of MTAs, ranging from 1.5 kW to 75 kW, based on output speed and a service factor of 1.4.

“The MTA is used across several industries where a shaft-mounted reducer is required. However, it is used most frequently in the quarrying and aggregates industries,” he says.

Trevelyan states that the Dodge range includes the traditional torque arm branded series – the Dodge Torque-Arm II shaft-mounted reducers which are belt driven, and the motorised MTA unit.

“Both units offer the exclusive metric bore, twin-tapered bushing that provides a sturdy, concentric grip of the driven shaft on both sides of the reducer. “This eliminates the excessive wobble and fretting corrosion normally associated with single-bushed shaft-mounted reducers,” he points out.

Trevelyan adds that Dodge’s bushings are made of ductile iron for shock resistance and are fully split to completely grip the driven shaft.

“As the bushing screws are tightened, the bushing is drawn inward, wedging itself firmly against the shaft. “To remove the unit, operators simply have to remove the mounting screws and insert them into the threaded holes in the bushing flange and turn them against the backing plate. They act as jacking screws and withdraw the bushing, allowing for the reducer to be removed, with no pullers required.”

Another key feature of the MTA is that the units enable any brand of IEC B5 flange motor to be used with the reducers.

Trevelyan adds that the units are a heavy-duty solution and are equipped with taper roller bearings that comply with the American Gear Manufacturers Association standards. The taper roller bearings provide the units with an average minimum bearing life span of 25 000 hours.