Operators shall control window units in groups as recommended by window
manufacturer for the particular window arrangement shown, unless
specifically indicated otherwise. Use mechanical operators of one of the
following types:
a.
On-Sill Operators: Centrally located, manually controlled
mechanisms for adjusting ventilators, assembled of bronze
telescoping shafts with machine cut threads. Conceal, except for
linkage members, by appropriate covers. Provide one operator,
secured to sill, for each window. Finish operators exposed to
view to match hardware finish. Finish covers to match window
casings.
b.
Geared Lever-Arm Operator: Power unit shall consist of
machine-cut gears and machined thrust bearings housed in dustproof
oil-tight case, with provision for lubrication. Provide torsion
shaft of standard black iron pipe not less than 25 mm one inch
inside diameter. Rigidly clamp steel or malleable iron operating
arms to shaft and connect to ventilator by push bar and hinge
bracket. Support operating mechanism on brackets securely
attached to building structure or mullions. No single line shall
extend more than 9 meters 30 feet from either or both sides of
power unit.
c.
Geared Rack-and-Pinion Operator: Unit shall consist of
machine-cut gears and machined thrust bearings housed in dustproof
oil-tight case, with provision for lubrication. Provide torsion
shaft of standard black iron pipe not less than 25 mm one inch
inside diameter. Rack shall be of steel, cut to a pitch that will
mesh accurately with the cut teeth on a steel or cast iron pinion.
Fasten pinion securely to torsion shaft. Rack shall have hinged
bracket for attaching to ventilator. Hold rack in mesh with
pinion by steel yoke with bearing rollers of solid brass or
cadmium plated steel. Support operating mechanism on steel
brackets securely attached to building structure or mullions. No
single line shall extend more than 15 meters 50 feet from either
or both sides of power unit.
2.11.3.1
Operating Arms and Racks
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NOTE: Delete when not applicable.
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Provide each ventilator not more than 900 mm 36 inches wide with single
operating arm or rack attached at center of rail. Provide each ventilator
more than 900 mm 36 inches wide with two operating arms or racks attached
to side rails or near ends of horizontal rail of ventilator.
2.11.3.2
Chain Control
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NOTE: Delete when not applicable.
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Provide power unit with hand chain, operating over chain wheel with chain
guard. Drill and secure wheel to worm shaft by key. Terminate chain
approximately 600 mm 2 feet above floor. Where building construction makes
it impracticable to hang chain vertically from power unit, furnish single
SECTION 08510
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