Patent Application
20070114332
Not Applicable
Not Applicable
Not Applicable
This invention relates to the opening sequence of a deploying parachute, specifically to attenuate the opening shock forces, the snatch force and the canopy opening force.
A parachute system normally consists of a suspended weight (referred to as the jumper), a harness (attaches the parachute to the jumper), a container (holds the packed parachute during freefall), a canopy (flexible material to slow the decent of the jumper) and suspension lines (attaches the canopy to the harness via Risers and Connector Links). The Risers (normally four, two pair (Left and Right, and Front and Rear)) are attached to the harness. At the end of each Riser there is normally a Connector Link (metal, oval ring or equivalent). The suspension lines are attached, in groups, to the Connector Links that are attached to the Risers which is attached to the harness. The canopy is normally contained in a bag to make packing easier and to help attenuate the opening shock during canopy deployment. A pilot chute is normally attached to the bag/canopy and is used to extract the bag/canopy from the container. With ram air parachutes a Slider is normally used. It normally consists of a rectangular piece of material with four grommets in the corners. The four line groups from the canopy are routed through the grommets. The slider is pushed up to the bottom of the canopy during packing. During deployment the Slider “slides” down the lines to the Connector Links. This slows and provides an orderly canopy deployment.
Two main opening shock forces are Snatch Force and Canopy Opening Shock. The Snatch Force is when the suspension lines are fully extended and the canopy is accelerated to the speed of the jumper. This is very sudden, sharp and over very quickly (less than a second). Next, the canopy will began to spread from its packed position to its fully inflated condition. With proper attenuation (i.e. bag, slider and proper design) and packing technique the Canopy Opening Shock will be spread over a short duration (several seconds). The Canopy Opening Shock may be less than the Snatch Force but of longer duration.
Older style parachutes (Round canopies) used material with a porosity that allowed air to penetrate it. They also had suspension lines that would stretch when a load was applied. When packed in a deployment device (sleeve or bag, etc.), generally the opening shock was not too great (there were exceptions however). Now almost all parachutes (except some military, emergency and special use) are of the Ram-Air type. The normal parachute material now is of Low or Zero-Porosity with non-stretchable suspension lines. The parachute is aerodynamically like an airfoil (airplane wing) and needs to maintain the airfoil shape. Many times the opening shock is high. The original Slider (non-patented) was developed in the 1970's. Normally it is a rectangular material with four grommets or rings in the corners. The suspension lines feed through 4 grommets or rings. The Slider is pressed against the canopy during packing to restrict the canopy initially and allow it to open in a controlled manner. Sometimes a Pocket would be sewed on the leading edge of the slider to further control the opening. The Slider is used on almost all Ram-Air canopies today. There have been patents issued on variations of the basic slider. Tandem parachutes (passenger attached to a tandem master with an extra large canopy) use a drogue parachute to slow the passenger/tandem master during freefall to the speed of a single jumper in freefall. Some older style “round” parachutes used a center line to pull down the apex of the canopy to increase the size of the canopy. Normally the “round” parachutes used a small opening or vent at the apex to increase stability. A small Pilot Chute is put in the wind stream and pulls the main canopy for deployment.
The opening shock is dependent on the difference in the velocity of the jumper and canopy upon line stretch (snatch force) and canopy deployment. Opening shock may be perceived differently by different jumpers. All would agree that opening the canopy shortly after exiting the aircraft (before reaching terminal velocity) will have less opening shock than when opening the same canopy at terminal velocity (maximum speed of a freefalling jumper). A larger jumpsuit, reduction in jumper weight, lighter canopy, smaller pilot chute or slower opening speed and proper packing procedure will assist to lessen the opening shock.
There is a multitude of prior art pertaining to parachutes, pilot chutes, drogue chutes and Slider variations. The pilot chutes and drogue chutes are used to extract the main chute or stabilize the load prior to the main chute deploying.
The Softer is unique in that it is used during deployment to slow the jumper prior to the opening sequence. It is attached to the connector links, not the bag or container.
Accordingly, several objects and advantages of my invention are:
The Softer is contained in the container then deploys automatically with the bag/canopy. It slows the jumper during the opening sequence thereby lessening the opening shock on the jumper for better and more enjoyable canopy deployments. The Softer is unique in that it is used during deployment to slow the load during the opening sequence and is attached to the connector links, not the bag or container.
10 Side of Softer material (2 needed)
12 Seam (attaching material (10))
13 Vent
15 Binding Tape for edge reinforcement
17 Attachment Loops to attach the Softer to riser connector links (2 needed)
40 Attachment Lines to attach the Softer or Quick Release Assembly to the riser connector links (2 needed)
51 Dee Ring (2 needed)
52 Retaining Pin (2 needed)
53 Small Rubber Band (2 needed)
54 Quick Release Tab with lanyard (2 needed)
A preferred embodiment of the present invention (Softer) is illustrated in
As shown in
When inflated, the Softer acts as a small drogue chute to slow the jumper's velocity permitting softer openings. The Softer is attached to one set (Left and Right) of the Connector Links or equivalent. The Front and Rear sets of Connector Links are together during initial deployment.
To permit a quicker and more positive presentation to the wind stream, the apex of the Softer is attached to the canopy deployment bag. One method is to attach a small rubber band on one of the bag line stow loops for apex stowage. This permits an easy attachment to hold the Softer during initial canopy deployment. It pulls the Softer into the wind stream. The apex has a vent (13) to make the Softer more stable and not collapse during deployment.
Various materials can be used for the Softer but generally Zero-Porosity parachute material is preferred. It is strong, thin (less bulk) and lightweight (less weight) and provides a lot of drag when deployed. While various shapes of the Softer (
Instead of the Quick Release Assembly (
Accordingly, the reader will see that, according to the invention, it is simple to attach to the connector links and pack. It has no affect on the freefall portion the jump. It deploys automatically with canopy deployment and can be collapsed or removed upon complete canopy deployment. It provides additional drag during the critical snatch force and canopy deployment phase. This will reduce the opening shock on the jumper for a safer and softer opening.
While the above description contains many specifications, these should not be construed as limitations on the scope of the invention, but as exemplification's of the presently preferred embodiments thereof. Many other ramifications and variations are possible within the teachings of the invention. For example, there should be some means to deflate or remove the Softer after deployment. Shown on this application is the preferred method. Various other means and methods would also work to accomplish the same objectives. A pressure release opening (vent—13) near the apex may be incorporated also.
Thus the scope of the invention should be determined by the appended claims and their legal equivalents, and not by the examples given.
