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Delroyd Hoist Worm Gear Drives for Steel Mill Charging Crane
Charging crane hoist drive gear boxes were failing prematurely at a large steel mill
in Northeastern U.S. The failures were causing unfavorable outages and expensive
periods of downtime.
Due to their desire and reputation to solve problems, Delroyd was called in to help
analyze the situation and develop a solution. A meeting was held at the mill with
various parties including an outside service group, mill engineers, maintenance
managers and Delroyd engineers. All aspects of the ongoing issues were reviewed
and an on-site inspection of a failed gearbox was performed.
Based on their findings, Delroyd engineering developed new worm gear sets utilizing
aluminum bronze gears and redesigned the bearing mountings to enhance strength
and durability. A carburize hardened, ground and polished alloy steel worm develops a
smooth, work-hardened surface on the aluminum bronze gear. Extra-heavy side plates
were used to connect the worm and gear shaft bearing supports, assuring proper
meshing of the gear under all conditions of load. A more rigid fabricated steel housing
design was utilized to reduce bending moment stresses. A redesigned, more efficient
lubrication system was also incorporated.
The Delroyd design changes resulted in extending the gearbox life by over five years.
The charging crane gearbox success prompted the mill to utilize Delroyd’s expertise by
providing gearboxes for their gantry cranes as well.
enclosed worm gear
reducers and worm gear
- Aluminum bronze gear
material for enhanced
- Carburize hardened,
ground and polished alloy
- Fabricated steel housings
and mountings for strength
- Redesigned lubrication