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Steel Rolling Doors-CG300

The pre-engineered curtain roller is made from one or more heavy gauge steel pipes suitably flanged to form a continuos barrel strong enough to support the curtain with an ample factor of safety. A low-stress torsion spring counterbalance of proper capacity to balance the curtain in all positions is built into the roller. Main bearings for the curtain roller are flange-type heavy duty ball bearings that make operation smooth and friction-free. These bearings are lifetime lubricated and sealed. The curtain hangers have an involute shape that allows the curtain to wind smoothly without lumping or distortion. When hand chain or power operators are used the drive end of the curtain roller is coupled to the operator by means of a sprocket and roller chain drive - hand crank operators are usually direct coupled.

ROLLING DOORS As manufactured by The City Gates Mfg. Corp., College Point, N.Y. shall be of service type and operated by means of either manual push-up, endless chain or motor.


WORK EXCLUDED Preparation of openings, structural supports, access panels, trim, field painting. On motor operated doors, exclude wire, wiring or disconnect switches.


CURTAINS to be composed of interlocking slats of (galvanized steel) (aluminum) (stainless steel) , designed to withstand a wind load of 20 Ibs. per sq. ft. Wind locks to be applied where required by opening span or heavier wind load. Galvanized steel slats to be from hot dipped copper bearing strip, with 1.25 oz./sq. ft. zinc coating, and phosphate coated for paint adhesion. Strip to conform to ASTM standards. For doors up to 14'-0 wide slats to be #22 Gauge; from 14'-0 to 18'-6 wide slats to be #20 Gauge; over 18'-6 wide, slats to be #18 Gauge. Alternate slats to be fitted with malleable iron end locks. Bottom of curtain to have reinforcing angles of (steel) (aluminum) (stainless steel)


COUNTERBALANCE ASSEMBLY to consist of helical torsion springs with a 25% safely factor, mounted on shaped cast anchors, supported by a continuous solid torsion rod. This mechanism to be permanently lubricated and enclosed within a steel pipe shaft , Deflection of shaft not to exceed .03" per lin. ft. The spring tension adjusting wheel is to be readily accessible from outside the bracket plate.

BRACKETS to be not less than 1/4" thick steel plate, to contain self aligning ball bearings for suspension of the counter balance assembly. Brackets to be mounted to the structural wall angle to form a self supporting member, and form an enclosure to the hood. Brackets to be reinforced with welded steel bands for support of hoods. Gears to be of high grade iron, cast from machine cut patterns.

GUIDES To be composed of structural (steel) (aluminum) (stainless steel) angles, minimum 3/16" thick, of sufficient depth to retain curtain under normal wind load. For doors requiring wind locks, guides to be provided with wind lock bars. Guides to be assembled with 3/8" diameter bolts spaced not over 3'-0" on centers.


HOODS to be not less than #24 gauge (hot galvanized phosphate treated steel) (aluminum) (stainless steel), formed to fit brackets, and reinforced top and bottom with stiffening returns, with intermediate hood supports where required by door width.

LOCKING provision for padlocks to be (slide bolts on push up doors) (chain holder on chain doors) (locking disc on crank doors) (self-locking gearing on motor operators).


FINISH on steel to be one shop coat of rust inhibiting metal primer, except on galvanized surfaces. On aluminum, finish to be mill. On stainless steel, finish to be 2B mill.

Product Line

Rolling Steel Solid Door

Commercial Coiling Grills

UL Classified Fire Rated Products

Doors for Special Applications

Spare Parts For Doors