2.3.1
Structure
The entire live load carrying surface of the ramp and rear attachment shall
be not less than 6 mm 1/4 inch thick, 350 MPa 55 ksi minimum yield
strength, low alloy, nonskid steel tread plate. Provide minimum 16 mm 5/8
inch vertical projections on the live load carrying surface. Bevel the lip
or ramp extension. Design load carrying surfaces to permit free movement
of powered hand or platform trucks, low lift pallet trucks, and fork lift
trucks. Fabricate lip hinge of not less than 6 mm 1/4 inch wall seamless
steel tubing.
2.3.2
Toe Guards or Skirts
Provide sides or edges, except front and rear edges, of the ramps which
rise above the surrounding loading dock with sheet carbon steel skirts or
toe guards of minimum 1.8 mm 14 U.S.S. gage nominal thickness. Toe guards
or skirts shall be smooth faced and mounted flush with the edges of the
ramp surface. Ensure sufficient depth of toe guards or skirts to protect
the full operating range of dock travel. Ensure the construction capable
of resisting a minimum lateral force of 4.5 kg 10 pounds with a maximum
deflection of 13 mm 1/2 inch.
2.4
ELECTRO-HYDRAULIC SYSTEM
Provide a separate and complete system for each dock leveler. Include an
electric motor, motor drive, hydraulic pump, hydraulic ram, pressure relief
valve, fluid reservoir, strainer, filter, hydraulic control-valve
cylinders, hose, piping, fittings, and hydraulic fluid. Incorporate a
means for filling and draining hydraulic fluid. Design cylinders, pump,
and control valves to withstand not less than 150 percent of the design
operating pressure. Provide hydraulic hose, fittings, pipe, and tubing
with working pressures based upon a minimum 4 to 1 safety factor of
bursting pressure.
2.5
ELECTRICAL REQUIREMENTS
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NOTE: Standard available ratings for 3 phase motors
are 230 or 460 volts. If motors are used with 208
volt distribution systems, a booster transformer
must be provided.
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NFPA 70, NEMA ICS 2, NEMA ICS 6 and NEMA MG 1. Provide [230] [or] [460]
volt electrical characteristics, three phase, 60 Hz alternating current
power supply. Provide all electrical equipment on the loading ramp.
Provide interconnecting wiring for components of packaged equipment as an
integral part of the equipment. Include motor, switches, junction box,
conduit, wiring cables, panel enclosed control station, motor controller,
heater coils, timer, transformer, terminal blocks, and fuses. Provide NEMA
ICS 6, Type 4, electrical enclosures. Color code all wiring.
2.5.1
Motor
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NOTE: Only electrohydraulic and air powered loading
dock levelers are equipped with electric motor which
activate the power system to raise and operate
leveler.
SECTION 11161
Page 12
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