Over the past decade, infrastructure engineers have been cautioning
municipalities and governing bodies across the U.S. about the deteriorating
condition of the country’s bridges and dams. The average age of the 609,380
bridges in the U.S. is now nearly 42 years old. These warnings have proven to
be justified with bridge failures such as the Minneapolis I-35W
Mississippi River bridge collapse in 2007.
In response to the looming crisis, extensive bridge inspection programs were
conducted nationwide with findings that, in some cases, caused immediate
bridge closures. Moveable bridges, including bascule lift, vertical lift and swing
bridges are susceptible to degradation due to the wear on their mechanical
systems from repeated open/close operations over time. Many of these bridge
drive systems are at the end of their useful lives.
Since 1887, Nuttall Gear has been known as innovators in the field of gear
engineering and leaders of setting gearing standards. For more than 60 years,
moveable structure engineers, bridge and dam mechanical OEM’s and bridge
authorities/owners around the country have come to rely on Nuttall Gear for
highly engineered, long-lasting gearbox solutions. Recognized industry-wide,
as a leader in the bridge market, Nuttall Gear engineers have presented
papers at Heavy Moveable Structures Biennial Symposiums.
EVERY BRIDGE GEARBOX IS UNIQUE
Nuttall Gear’s extensive application expertise combined
with their exceptional engineering capability is critical
to their success. Every bridge gearbox is unique so
understanding the requirement differences associated
with each bridge type drive system allows Nuttall Gear
to meet customer expectations faster and more cost
effectively than others.
Nuttall Gear engineers work very closely with customers
to meet all the various bridge challenges including
vertical lift bridges that require dual matching drivetrains,
the need to accommodate the heavy weight typically
encountered on most rail swing bridges, and the load sharing
gearbox requirements on larger, dual-span
bascule bridges to ensure a level lift of both spans.
STRUCTURED FOR PERFORMANCE
Nuttall Gear has refined their internal processes to allow
for highly efficient bridge drive design and manufacturing.
Advanced technologies are utilized throughout all
operations including through hardening or carburizing of
the gearing as well as hobbing, grinding, machining…
all performed in-house to save time and costs while
controlling quality and craftsmanship. Nuttall Gear’s
commitment to the bridge industry is company-wide
from quality documentation through selective use and
application of required paint and coatings.
TESTING CAN SIGNIFICANTLY INCREASE THE COST OF
PRODUCING A GEARBOX BY 15-20%.
While substantial investments have been made in
manufacturing areas, the most recent focus has been on
expanding comprehensive, cost-effective and convenient
in-house testing capabilities to meet often demanding
moveable bridge drive customer load test requirements.
Most moveable bridge drives are quite large and need
to be tested to very high torque loads. The bridges
also have differential style gearboxes that require load
equalizing on each output shaft.
Nuttall Gear technicians utilize the latest testing
techniques and technology including laser alignment
of all drivetrain components, twin dynamometers, and
massive, custom-built test stands which allow two
15,000 lb. gearboxes to be mounted and tested back-to-back
on inclines up to 75 degrees.
Customers enjoy significant benefits by utilizing the
innovative in-house testing capability including:
- Complete control of the test schedule
- Elimination of transportation costs to an outside
test facility (which can be significant for a 15,000 lb.
- Initial run and diagnostic challenges can be quickly
overcome by technicians without having to remove the
gearbox from the test floor, saving considerable setup
- Nuttall Gear can be significantly more cost-effective vs.
competitors that outsource testing at an off-site facility.
Through a focus on continuous improvement, innovation
and a dedicated team, Nuttall Gear provides the highest
quality gear drive solutions with the lowest cost of
ownership to the bridge and dam market.