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Value
Added Cam Tube System
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In
the Australian market, it is widely recognised that Flee want to
reduce periodic maintenance and ultimately eliminate major
maintenance. Throughout the trucking industry, S-cam journal service
life and ease of maintenance have long been among the most
criticised features of conventional trailer S-cam brake designs.
The
increasing market penetration of extended-service brake and hub
systems increased the Flee’ and owner operator’s desire for
systems that extend brake component lives. Maintenance intervals
have been extended on these productsts and the cam supports are
becoming the weal link in the system. In extreme conditions an
unprotected cam and bushing have the potential of wearing out before
the extended-service brake linings.
Nowhere
has the demand for an improved S-cam support system been more
consistently demonstrated than in Australia. In this market, users
are constructing makeshift aftermarket devices. They must be welded
or otherwise retrofitted to existing brake structures. Some of these
crude systems have no seals or minimal seals, others have bronze
bushings or no bushings at all, allowing the cam to float in the
rough tube. These aftermarket designs create weight penalties; on
long trailer axle camshafts the added weight can be as much as 3.6
to 4.6 kg per axle. Cam tubes are not new. For many years, cam tube
like structures have been widely used in the truck and tractor
market as an integral component of a self-contained brake. It has
been well known by maintenance managers that truck and tractor cam
bushings and seals are traditionally more durable than those on
trailers.
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The
Hendrickson Advantage
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Flee
and owner operators have asked for longer life brake components,
reduced maintenance costs and increased uptime for their trailers.
In response, Hendrickson Asia Pacific delivers the first standard
Cam Tube System for trailer brake systems. Hendrickson utilised
design principles found in S-cam support structures that are widely
accepted in the truck and tractor market, developing at no extra
cost, a value-added design improvement to the existing cam support
structure.
Hendrickson
made the Cam Tube System standard equipment on all INTRAAX®
models
(to be phased-in beginning in the spring of 2001). The basic design
principle behind our cam tube keeps contaminants away from the
camshaft, which extends the life of the shaft journals and bushings,
reduces maintenance and protects the trailer. Designed to fit both
standard and HXS® extended service brake assemblies, the
Cam Tube System includes a modular steel cartridge that encloses the
S-cam shaft on each wheel-end assembly. Encased at each end of this
cartridge are the camshaft support bushings and seals. Relocating
the outer camshaft bushing from the spider to the tube optimises the
cam tube structure. This
provides a significant weight reduction of nearly 3 kg per axle from
what is already the industry’s lightest suspension, axle and brake
system.
Industry
studies have shown that bushing life is a function of containment
levels in the areas where the cam journals contact the bushings.
When compared to existing trailer brake designs that have separate
seals surrounding each journal and bushing individually,
Hendrickson’s Cam Tube System reduces contaminant entry points by
50 percent. 
The spring-loaded double lip seals are designed to greatly limit the
potential of contaminant entry by providing two redundant barriers
to entry. Ozone inhibitors in the seal material prevent degradation
by sustaining the life of the rubber. This system holds seven times
more grease than conventional designs. Any debris passing the seals
is effectively diluted, minimising the potential of damage or wear.
While the system provides customers with extended service intervals.
In
case of an accident or physical damage, the modular cartridge
facilitates simplified replacement versus a conventional S-cam
support system. Cam Tube replacement ki are available at major
par distribution centres. However, with line haul applications,
the Cam Tube System has the potential of lasting the life of the
vehicle. Due to i unique design, the Cam Tube System cannot be
retrofitted on previous generations of
Hendrickson trailer suspensions. Hendrickson’s Cam Tube System
alleviates the problems of S-cam bushing and seal maintenance,
allowing customers to recognise all of the benefits possible from
their investment in these systems.
