The
Lemar moving Powerwalk has proven itself to be a welcome addition
to high traffic observation/exhibit areas. Because of its smooth,
quiet, and safe operation there is no hesitation on the part of
the public to use the walk.
The
speed of the moving walk is adjustable for optimal performance in
it's particular application. Its normal operating speed is about
20 feet per minute.
Due
to the powerwalks unique crescent shaped pallets linked to form
an endless surface, it is capable of making bends and turns of up
to 180°. The riding surfaces do not slide over one another.
The edges of one pallet abut the next. The meeting surfaces are
smooth and flush. The gently curved crescents allow for cornering.
A rider can stand so his/her feet span two adjacent pallets and
still go around the bends, with little or no knowledge of a direction
change or ride discomfort.
The
pallets are molded in black polyurethane elastomer on a composite
structural core suspended in a steel mold. The mold. is encapsulated
with viscous, two-part polyurethane to achieve a designed thickness
of three millimeters overall and an accurate profile. This coating
is extremely wear-resistant and time proven.
The
finished pallets, manufactured to ensure complete interchangeability,
are bolted onto the carriages. Any number of carriages can be linked
to provide an endless chain to which the pallets can be bolted to
complete a conveying surface. The carriages are fabricated from
mild steel, machined to the designed pitch and then fitted with
a self-aligning joint. A
pair of lugs are positioned under and centered to one side of the
carriage to connect with the driving chain. An electrogalvanized
coating is applied to the finished carriage fabrication for lasting
protection. At one end in the center of the carriage, a centering
wheel assembly is located to guide the pallet carriage around a
preformed trackway. The wheel is comprised of high density, plastic
tyre molded onto a precision sealed, life ball bearing. The assembly
is secured into place by a 12 mm bolt tapped into the carriage fabrication
and further locked by a set screw.
The
above three dimensional drawing shows the pallets, carriages, the
riding bed rails, as well as the frame.
The
below picture shows the Powerwalk on the right hand side. The individual
pallets are fastened to the carriages with bolts (seen here as three
white circles on the pallets).
Safety
Controls
The
system contains emergency stop buttons (the amount of stop buttons
depends on the layout of the system. The walk is driven by a caterpillar
drive unit whereby an endless chain, with lugs attached, meshes
with and drives against lugs on the underside of each carriage.
The drive chain
is a regular precision transmission chain and is tensioned over
regular chain sprockets. The head shaft of the caterpillar drive
unit has a direct mounted worm driven gearbox, providing the motor
speed reduction and is selected for efficiency, reliability and
low noise characteristics. An electric motor is coupled to the gearbox
and is in conjunction with a variable frequency speed controller.
The motors are four pole and three phase that are totally enclosed
units selected and engineered for the specified conveyor length,
load and application.
A stationary
handrail is also provided for users.
People
are alerted by signage upon reaching the end of the Powerwalk. In
the case of an accidental fall or dropped item at the end of the
Powerwalk the drive motor will immediately shut off allowing the
person to get up or to retrieve their item safely.
Another
safety feature is the toe recess kick plate which forms a skirting
between the moving plates and the stationary walkway preventing
soles, laces, or other items from becoming trapped or ensnared between
the moving walk and stationary walkway.
Earphones
& Controls
Equipped
with earphones the Powerwalk allows visitors a headphone narrated
journey through the exhibit enhancing their experience not only
visually but audibly as well.
Running
along side the moving Powerwalk is a stationary walkway. This
allows visitors to stop moving at points of interest while allowing
others to pass by without hindering observation or obstructing
traffic flow.
The
removable plates constituting the stationary walkway also allows
access to the moving walk and its entire supporting structure,
carriages and drive. The framework is manufactured in three-meter
modules of mild steel sections and pressings. The center guide
rails and bed rails are bolted to the cross ties. The cross ties
are supported and leveled on robust screw-adjustable legs. The
base of the outer line of legs provides the attachment point for
a toe recess kick plate which, in itself, forms a skirting. The
framework is planned and located on the layout plan to support
a static load of 300 kg/m.