Fleet Maintenance - 19

cause damage and subsequent premature failure
to motors. "This is where fleets can run into a lot
of problems," Griessner says.
There are certain precautionary measures fleets
can take, Griessner adds. "Separators, for example,
don't allow batteries to drain as much. You can also
put battery state-of-charge gauges on the liftgate
controls. If the charge is too low, the driver is alerted and knows he or she has no choice but to start
the tractor to get the liftgate operating. But, even
with measures such as these, low-voltage situations
continue to be a problem for the fleet industry."
Terry Eyink is an engineer with Thieman
Liftgates, another manufacturer of hydraulic
liftgates. He says electrical connections and
grounds are always critical to get signals from the
12V positive source to the switches and valves.
They are also critical for current to flow properly
from the battery source through the DC loads on
the liftgate, to grounding points, and back to the
battery's negative post. "Breaks or weak connections anywhere in that loop will not allow current
to flow properly," Eyink points out.
So, what can a fleet do?
"A loose terminal can cause problems," Walker
says. "Corroded connections can cause problems.
A wire rubbing against a sharp edge can wear
through and short out, also causing problems.
It's a good practice to run through the electrical
connections every three to six months. Hit them
with a wrench and make sure everything is tight.
Visually inspect for balls of corrosion. Make sure
the grounds are good. These are all basic maintenance items that can make a big difference with
the uptime of the liftgate."
Voltage testing is another important step fleets
can take. However, Eyink says technicians often
make one critical mistake. "Technicians often
check voltages when there is no electrical load
on the system," he explains. "Many electrical
problems can only be easily located when there
is an electrical load because current multipled by
resistance - resistance caused by weak connections - results in voltage drops."
According to Eyink, a technician could ask someone for assistance by hitting a switch to activate the
liftgate. While safely positioned away from the path
of the moving liftgate, the technician can check to
see if the voltage stays up in the necessary 10.5V
to 11V range, or if it drops down to around 3V or
4V. "Many solenoids and valve coils won't even
function if voltages drop below 9.5V," Eyink adds.

» The LRST 40EST from Thieman Liftgates
is a stowaway liftgate model featuring a
self-leveling and adjustable platform.
Photo courtesy of Thieman Liftgates

what he calls a five-step liftgate selection process.
1. Type and size of vehicle. The chassis a fleet
uses, along with bed height and associated
overhangs, limits which liftgates are practical.
"For instance, if the bed height is really low, it
is hard to use a "tuck-away" liftgate because
there isn't any room to fold it out," Griessner
explains. This liftgate style features a foldable
platform that collapses and stores under the
back of the trailer.
2. Type and handling of load. Is the cargo palletized? What are the dimensions and weight? What
type of pallet jack will the driver be using? Is the
driver loading bread carts that are high and may
tip over easily, requiring a liftgate with a platform
that remains perfectly level? Those are the types
of questions fleets should be asking.
3. Capacity. "It sounds like an easy thing, but there
is a lot to keep in mind," Griessner says. "It's a
good idea to spec for the worst-case scenario,
even if it's a one-off load." For instance, if the
driver will ever be unloading pallets of water
with a 700- or 800-lb electric pallet jack or even
200-lb manual jack, that is a lot of weight. And
don't forget about that driver, whom, Griessner
says, should be estimated to weigh 250 lbs.
"Things like driver weight and pallet jack
weight are often forgotten in this equation,"
Griessner says. "Whatever number you arrive at,
» A column lift, such as Maxon's BMR, is
heavy duty, making it the liftgate of choice
in industries such as food and beverage
where heavy cargo loads are the norm.
Photo courtesy of Maxon Lift

make sure you have a liftgate with that capacity.
If a fleet has a liftgate without the necessary
capacity, it will often run into efficiency issues
because the liftgate becomes slow or can't lift at
all. There are also safety issues because an overburdened lift will break down sooner or later."
4. Type of liftgate. Fleets should think about how
often they will need to use the liftgate. "This
depends very much on the specific application
and how many stops a driver will make in a
given day," Griessner says.
5. Bed height. Just like with capacity, fleets should
specify for the worst-case scenario, which is a
fully laden truck or trailer, and whatever the
minimum bed height is a driver can work with.
For instance, one of Maxon's premium Tuk-AWay brand liftgates needs at least 46" laden bed
height or it cannot be stored away.
Anthony Liftgates' Walker says fleets should
also pay attention to a dedicated ground cable.
"Over the years, fleets would often charge trailer
liftgates through a single power cable running
back to the dedicated batteries on the trailer,"
Walker says. "They would often ground back
through the fifth wheel, but that can cause problems because it isn't a good connection. The same
thing can happen on a straight truck. The ground
should always be as direct as possible to get the
best pull of electricity."
Eyink says the most common missteps fleets
make when specifying liftgates relate to cargo
weight, bed height, and if cargo door access without using the liftgate is required. Other frequent
missteps tie to battery charge.
"Fleets don't always consider drive time
between stops, the number of liftgate cycles per
stop, or idle time to shutoff," Eyink says. "These
things help ensure they will have enough power
to run their liftgate correctly. Considering this
will help to determine if optional charging kits are
necessary, along with which one is right for them."
According to Griessner, fleets need to spend
time thinking about the recharging issue when
specifying a liftgate. "Fleets need to understand
how much is demanded of the liftgate-then they
can specify it correctly," Griessner says. "With an
energy usage profile, liftgate manufacturers can
recommend alternative charging solutions such
 Continued Page 20

Specifying a liftgate

Electrical issues are common for all types of liftgates. Fleets should keep that in mind when drivers report liftgate performance issues. There are
also some key items fleets should keep in mind
when specifying a liftgate in the first place.
For starters, Thieman Liftgates' Eyink says fleets
need to identify the required cargo capacity, along
with the types of cargo they'll be unloading and
how they'll go about unloading it. "A fleet may
choose one style if it is unloading milk crates from
the side of a refrigerated trailer, but would want a
completely different style of lift if unloading pallets
from the back of a box truck," Eyink explains.
Maxon's Griessner says factors like capacity and
cargo handling are important to evaluate as part of

May 2019 | VehicleServicePros.com

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Fleet Maintenance

Table of Contents for the Digital Edition of Fleet Maintenance