TECHNICAL FIELD

[0001] The present invention relates to parachute systems and the like, and more particularly, relates to a method and apparatus for severing a connection.

BACKGROUND INFORMATION

[0002] Parachute rigs typically contain a main parachute or canopy connected to a harness using a riser webbing. The riser webbing typically includes a plurality of high strength lines, typically nylon, spectra, polypropylene, or the like. These lines must be strong enough to withstand the forces generated during a parachute drop, yet lightweight, flexible, and compact. [0003] In the event of a main parachute malfunction, the riser webbing attaching the parachute to the harness container must be severed to release the main parachute and allow a clean deployment of the secondary parachute. Traditionally, this has been accomplished using a quick release mechanical device.

[0004] Extremely heavy cargo loads (such as pallet loads or the like) typically employ a drogue parachute. The drogue parachute basically consists of a small, easily deployed parachute that is connected to the cargo load via a length of webbing which sits on a track of rollers. The drogue parachute is released while the load is still within the cargo drop area of the airplane and the drag or force

generated by drogue parachute pulls the cargo out of the airplane.

[0005] During flight, automatic clamps in the roller system secure the cargo pallet and prevent it from moving. In the event of a malfunction where the cargo pallet is stuck in the airplane but the drogue parachute is deployed, it is imperative that the drogue parachute be immediately released as forces generated by the drogue bridal can be over 60,000 pounds and can cause the airplane to crash. Because of the tremendous forces generated by the drogue bridal, mechanical advantage quick release devices are not practical. Traditionally, explosive bolts or explosive webbing cutters have been used to sever the drogue parachute from the cargo pallet. Unfortunately, these devices are very expensive and are also subject to restrictions in transportation and handling.

[0006] Accordingly, there exists a need to replace such pyrotechnic cutters with a non-explosive, non-restricted, reusable device. There also exists a need for a highly reliable, low cost device and method for severing webbing under a load that can vary from low to extremely high tensions.

[0007] It is important to note that the present invention is not intended to be limited to a system or method which must satisfy one or more of any stated objects or features of the invention. It is also important to note that the present invention is not limited to the preferred, exemplary, or primary embodiment (s) described herein. Modifications and substitutions by one of ordinary skill in the art are

considered to be within the scope of the present invention, which is not to be limited except by the following claims.

SUMMARY

[0008] According to one embodiment, the present invention features a parachute system. The parachute system includes webbing adapted to connect a parachute to a payload and at least one heater disposed about the webbing. The heater heats a portion of the webbing sufficiently enough to cause the webbing to sever when under tension. The heater may include a nichrome wire, an etched foil heater, or a resistance heater. The heater may be laminated to the webbing, molded to the webbing, laminated to the webbing, or secured to the webbing with adhesive, tape, or stitching. The webbing may include a plurality of strands. [0009] According to another embodiment, the present invention features a disconnection apparatus. The disconnection apparatus includes a heater for heating a portion of a parachute webbing such that the portion separates when under tension. The heater may be secured to the webbing via lamination, stitching, taping, adhering, and molding. Additionally, the heater may be selected from the group consisting of a nichrome wire, an etched foil heater, and a resistance heater.

[0010] According to yet another embodiment, the present invention features a method of severing a webbing of a parachute. The method includes the acts of providing a webbing connecting a parachute to a harness, exerting a tension through the parachute webbing, and heating a portion

of the parachute webbing thereby reducing the strength of the webbing such that the tension causes the parachute webbing to separate.

BRIEF DESCRIPTION OF THE DRAWINGS [0011] These and other features and advantages of the present invention will be better understood by reading the following detailed description, taken together with the drawings wherein: [0012] FIG. 1 is a plan view of one embodiment of the present invention;

[0013] FIG. 2 is a plan view of one embodiment of a high- weight parachute release mechanism;

[0014] FIG. 3 is an exploded view of the high-weight parachute release mechanism shown in FIG. 2; [0015] FIG. 4 is a plan view of one embodiment of a low- weight parachute release mechanism;

[0016] FIG. 5 is an exploded view of the low-weight parachute release mechanism shown in FIG. 4; [0017] FIG. 6 is a plan view of one embodiment of a composite release mechanism;

[0018] FIG. 7 is a plan view of one embodiment of the present invention featuring a laser source heating element; [0019] FIGS. 8 illustrate a severing test of Type 3 webbing under a tension of approximately 800 lbs; and [0020] FIGS. 9 illustrate a severing test of Type 7 webbing under a tension of approximately 5500 lbs.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0021] According to one embodiment, the present invention features a parachute apparatus and severing method 10, FIG. 1, which allows a parachute 11 to be released from a harness 18 nearly instantaneously over a large range of tensions/forces varying from relatively low to extremely large. The present invention releases the parachute 11 without the use of pyrotechnic cutters or mechanical advantage devices. As will be explained in greater detail hereinbelow, the present invention creates a controlled defect into the parachute webbing 14, thereby weakening the webbing 14 to the point were the forces/tensions experienced during its operation cause the webbing 14 to release the parachute 11. [0022] The apparatus and method 10 severs the webbing 14 through the use of a heating element 12 disposed on or about at least a portion of the webbing or line 14 to be severed (collectively referred to hereinafter as "webbing") . The heating element 12 generates heat that is quickly transferred to the webbing 14. High strength webbing 14 traditionally and commonly used in parachuting (as well as other applications) are typically manufactured from nylon, spectra, or polypropylene. The present invention includes the realization that as these materials are heated, the strength of the material is quickly diminished. While not a limitation of the present invention unless specifically stated otherwise, it has been found that these materials begin to melt and loose their strength at fairly low temperatures, for example less than approximately 400 ⁰ F.

[0023] Rather than severing the webbing 14 by mechanically cutting (e.g., using pyrotechnic cutters), the present invention 10 weakens at least a portion of the webbing 14 by heat, radiation, or laser such that it looses its strength and breaks under the forces experienced by the webbing 14. The webbing or severable material 14 preferably has a melting point high enough to such that the severable material 14 will function during normal parachuting operating temperatures, but low enough such that its structural strength is compromised to the point where it will severe under the loads experienced during a parachute drop without excessive heating requirements.

[0024] In the preferred embodiment, the webbing 14 is constructed from nylon, braded Spectra ® Fiber, polypropylene or similar material. Spectra ® Fiber is an ultra high molecular weight polyethylene fiber that melts at a very low temperature ranging from approximately 240 ⁰ F to approximately 280 ⁰ F. It is important to note that this temperature range is for illustrative purposes only, and is not a limitation of the present invention unless explicitly claimed as such. As discussed above, the present invention 10 includes any material 14 having sufficient strength under normal parachute operating temperatures that can also be quickly heated to the point where its structural strength is compromised such that it will severe under the loads experienced during a parachute drop.

[0025] The present invention 10 includes any device or method for heating 12 the webbing 14 such that the webbing 14 looses its strength and is severed. Because the webbing 14 is always under tension, only a small portion of the webbing

14 needs to be weakened in order for the webbing 14 to break. While a large section of the webbing 14 may be heated, heating a small section of the webbing 14 is preferable because it reduces the energy requirements and reduces the time it takes to sever the webbing 14.

[0026] The present invention features may feature a single heating source 12 or multiple heating sources 12 disposed on one or more sections of the webbing 14 connecting a parachute 11 to a parachute harness 18. The heating source 12 is preferably connected to a power source 20 that provides the energy needed to generate the heat. According to one embodiment, the power source 20 may be remotely located relative to the heating source 12. For example, the heating source 20 may be secured to the parachute harness 18 or may be secured to the cargo load 16 or to another part of the parachute equipment. Alternatively, the power source 20 may be disposed proximate the heating source 12 (for example, but not limited to, an integral part of the heating source 12) . [0027] According to one embodiment, the heating source 12 may include a 36 gauge nichrome wire, an etched foil heater (for example, but not limited to, a kapton foil heater) , a resistance heater, or any other device or means known to those skilled in the art which quickly generates heat. Etched circuit board type heaters can be mass-produced and easily laminated to the webbing 14.

[0028] As discussed above, the heating element 12 is preferably disposed proximate the webbing 14 that is to be severed. The number and placement of the heating sources 12 will depend upon the heat transfer requirements, the thickness and strength of the webbing 14, as well as the type

of material used and is within the knowledge of one skilled in the art. It is important that the heating source 12 transfers heat quickly to the webbing 14 such that the strength of the webbing 14 is reduced quickly. [0029] It is also important to note that the heating source 12 need not heat the webbing 14 to the point were the webbing 14 actually melts. The heating source 12 need only transfer enough heat to the webbing 14 to cause a controlled defect in at portion of the webbing 14 such that the strength of the webbing 14 is reduced enough whereby the forces/tensions generated during the deployment of the parachute are sufficient to sever the webbing 14. Alternatively, the heating source 12 can transfer enough heat to physically cause a portion of the webbing 14 to actually melt.

[0030] The present invention may also include a triggering device 21 that transmits/receives an activation signal causing the heating source 12 to activate. The triggering device 21 includes any device known to those skilled in the art and may be wireless.

[0031] The present invention also features a release mechanism 10, FIGS. 2 and 3, which is particularly suited for use as a high-tension release 60. The high-tension release 60 includes either a single strand 62 looped around itself or a plurality of strands 62 made from the severable material 14. The strand 62 is preferably disposed around a first and a second bushing 66, 68 using fasteners 70. The bushings 66, 68 may be connected to parachute lines such as drogue parachute lines, main parachute lines, or the like.

[0032] The strand 62 preferably forms a central region 72 wherein the two sides of the strand 62 are in close proximity to each other. At least one resistive heating element 12 is preferably disposed within the central region 72. By placing the heating element 12 in the central region 72, the heating element 12 is able to quickly create the controlled defect in both sides of the strand 62. In the preferred embodiment, the strand 62 preferably includes a plurality of layers 74, preferably having a heating element 12 substantially disposed or sandwiched between each layer 74.

[0033] According to another embodiment, the present invention features a release mechanism 10, FIGS. 4 and 5, which is particularly suited for use as a low-tension release 80. According to this embodiment, the low-tension release 80 preferably features a strand 62 of the severable material 14 that forms a first and a second loop 82, 84 for connecting to parachute lines such as drogue parachute lines, main parachute lines, or the like. The ends 86 of the strand 62 are preferably secured to the main body region 88 using any method known to those skilled in the art including, but not limited to, stitching, adhering, or fastening.

[0034] At least one resistive heating element 12 is secured to the main body region 88. In the preferred embodiment, the resistive heating element 12 is secured to the main body region 88 in an area between the ends 86 where there is only a single layer of the strand 62. This facilitates creating the controlled defect in the strand 62 since a minimum amount of the severable material/webbing 14 must be weakened. The resistive heating element 12 may be secured to the strand 62 in any manner known to those skilled in the art, but preferably

includes a fastener 90 that is secured to one end 86 of the strand 62. Optionally, a cover 92 may be provided to protect the resistive heating element 12 and to aid in creating the controlled defect. [0035] According to yet another embodiment, the release mechanism 10, FIG. 6, features a wound composite release 100, preferably having a first and a second end loop 101, 103 which may include bushing 105, 107. The wound composite release 100 preferably includes one or more resistive heating elements 12 disposed about a composite fabric body 102 made from a severable material 14 that does not require any sewing. Examples of the composite fabric body 102 include, but are not limited to, wound continuous filament, wound webbing, and laminated fabrics. Resin (such as, but not limited to, CA, urethane, and epoxy) is preferably used to hold the fibers or webbing from unraveling or separating. Testing has shown that the sheer strength of a resin lapped joint on Spectra ® to be between about 1200-2800 pounds/sq. inch, depending on the resin used. This is significantly higher than sewing. [0036] While the present invention has been described above wherein the heating element 12 is a resistive heating element, the present invention also features any other method known to those skilled in the art for heating the severable material 14. For example, the heating element 12, FIG 7, may feature one or more laser sources 12 secured to the severable material 14. The laser source 12 preferably includes a housing 13 and optics 15 to focus and direct the laser energy 17 towards the severable material 14 to create the controlled defect. The laser source 12 is preferably connected to a power source 20.

[0037] Tests of the present invention have shown that the webbing 14 up to approximately .080" can be severed almost instantaneously. For example, FIGS. 8 illustrate a test of Type 3 webbing employing the present invention wherein the webbing was placed under a tension of approximately 800 lbs. Upon activation, the webbing completely severed within 58 milliseconds. FIGS. 9 illustrate another test of Type 7 webbing employing the present invention wherein the webbing was placed under a tension of approximately 5500 lbs. Upon activation, the webbing completely severed within 32 milliseconds. Tests have also been successfully performed using the present invention with Type 8 and Type 28 webbing

14 at tensions up to approximately 8000 pounds.

[0038] While the present invention has been described with respect to a parachute system, this is not a limitation of the present invention and has been done to satisfy the best mode requirement. Those skilled in the art will readily recognize that the present invention is applicable in many other areas of technology. [0039] As mentioned above, the present invention is not intended to be limited to a system or method which must satisfy one or more of any stated or implied object or feature of the invention and should not be limited to the preferred, exemplary, or primary embodiment (s) described herein. The foregoing description of a preferred embodiment of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. Obvious modifications or variations are possible in light of the above teachings. The embodiment was chosen

and described to provide the best illustration of the principles of the invention and its practical application to thereby enable one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as is suited to the particular use contemplated. All such modifications and variations are within the scope of the invention as determined by the claims when interpreted in accordance with breadth to which they are fairly, legally and equitably entitled.