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Gearbox keeps sculpture hammering away for over a decade

Seatlle, WA -- Nov. 5, 2002 -- A huge, 48-ft high "Hammering Man" hollow-fabricated steel sculpture in front of the...


Seatlle, WA — Nov. 5, 2002 — A huge, 48-ft high “Hammering Man” hollow-fabricated steel sculpture in front of the art museum in Seattle, Wash., hammers away continuously at a piece of metal, its giant mechanical arm controlled by a 3-hp motor and a Cone Drive double enveloping worm gearbox.

Designed to represent the worker, the figure hammers four times per minute 15 hours per day, with just one day’s respite per year on Labour Day; and it has been doing this for the past 11 years — over 12 million hammer strokes — without any problems with the gearbox.

Jim Virmala from Cone Drive, who dealt with the original installation in 1991, explains, “The designers wanted a gearbox that would operate in a quiet and smooth manner but would be rugged and durable as well.

“A double enveloping design, where the worm and gear wrap around each other, was a clear favourite due to its high torque capacity and ability to handle heavy loads.”

A gearbox with a ratio of 450:1 was provided with special breathers to cope with the outdoor environment.