1. Field of the Invention
This invention relates to parachutes.
2. Prior Art
Parachutes having vents are known. These parachutes have shroud lines extending upward from a harness to the periphery of a canopy made of a fabric, with radial lines extending up the canopy to a vent band secured to the canopy and extending around the periphery of the vent. To carry the load which is transmitted from the harness upward through the shroud and radial lines, the parachute is provided with a plurality of vent lines. The ends of each of the vent lines are secured to the vent band on opposite sides of the vent opening so that each vent line lies on a diameter of the vent opening.
The ends of the vent lines are evenly spaced around the periphery of the vent opening. The conventional parachute is made by starting at one point on the vent band and sewing the vent lines, one at a time, to the vent band. This sewing operation progresses around the vent band in a clockwise (or counterclockwise) direction for 180 degrees, at which time the operation is completed.
A major disadvantage of this structure is that, while the ends of the first and last vent lines sewed lie next to each other on the vent band, the centers of these lines, where all of the vent lines cross at the center of the vent opening, are separated by all of the other vent lines. The first vent line sewed to the vent line will lie at the bottom of this stack and the last will lie at the top of the stack. Under a load, these adjacent (on the vent band) vent lines extend from the vent band at an angle to each other such that the tension forces applied to the vent band by these vent lines under a heavy load tends to tear the vent band.