Trap Doors 300 PSF Hinged Cover - Type J

Type J Trap Doors - 300 PSF Hinged Cover is aluminum or steel construction, single or double leaf design, with 300 PSF reinforcing and engineered lift assistance for controlled cover operation. Cover is 1/4 inch aluminum or steel diamond pattern plate. Channel frame has a 1-1/2 in. drain coupling. Lifting mechanism is compression spring operators for controlled cover opening and checking downward when closing. The lower tube interlocks with a flanged support shoe fastened to a formed 1/4 in. gusset support plate. Cover has a hold-open arm to automatically lock cover in open position. Hinges are heavy forged brass with 3/8 in. diameter minimum Type 316 stainless steel pins. Hardware is zinc plated and chromate sealed. Finish is mill finished aluminum with bituminous coating applied to exterior of frame, or red oxide primed steel. Available in four frame opening dimensions for steel and four for aluminum.