JPS5910902B2 - Elastomeric cushion devices for products and objects - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for protecting products or objects;
More particularly, the invention relates to a cushion device having a flexible chamber filled with a gaseous medium and protecting objects or products from damage.

Traditionally, packaging materials have been made by heat-sealing air-containing chambers between sheets of plastic to provide cushioning protection to the product during handling and shipping.

The chamber is separate, usually cylindrical or spherical, and contains air at atmospheric pressure. The sheet is usually non-elastomeric and consists of a laminate of several film layers, one or more of which is a barrier material (e.g. PVDC saran) and one or more other layers which are heat sealable. be. Thin, single layer (non-laminated) elastomeric films have been found to be impractical as cushioning materials due to their relatively high gas diffusivities for many gases. A gas-filled chamber flattens out in a very short time if a pressure difference exists between the gas in the chamber and the surrounding atmosphere. For example, if the chamber is formed by elastically expanding a film, the chamber will lose approximately 50% of its original volume within one to four weeks from the time of manufacture and become essentially flat in approximately six months. Laminated films can be heat sealed only at the edges and have relatively poor physical properties in all but the most expensive films. Barrier films with low diffusivities for many gases are used to prevent air from being squeezed out of the chamber when external loads are applied over long periods of time or when the material is exposed to high temperatures. In current products, the chamber is preformed and then partially inflated, thereby forming a somewhat wrinkled, non-pressurized chamber that allows the gas contained therein to expand and contract, causing the cushion product to overheat. Enables transportation by aircraft without swelling or rupturing. One type of known cushion device is disclosed in US Pat. No. 3,589,037. Because thin, laminated barrier-type materials are used in current cushion devices, the pressure in each chamber is approximately 3
Above ~4 psig, the cushion material will burst.
Laminated barrier materials are difficult to heat seal, so the welds that join the sheets together are weak and degrade with age or temperature. Therefore, conventional cushion devices are limited in the steady state loads they can support. For example, a load of 150 pounds per square foot is often specified as a maximum. Furthermore, conventional cushioning devices are very limited in the dynamic loads (shock loads) they can withstand without rupture or loss of air. As a result, the use of cushioning devices is typically limited to protecting only lightweight products such as instruments, electronic components, and the like. Attempts have been made to use conventional cushioning devices in fields other than the packaging field, such as elastic, shock-absorbing shoe insoles, cushioning materials as a substitute for foam butts in shoes, padding for athletic equipment, etc. .

However, these attempts were unsuccessful due to the fundamental problems of brittle materials, weak welds, and large volume changes caused by changes in altitude. It is an object of the present invention to be made from high strength, fatigue resistant elastomeric materials, have high structural strength and the ability to withstand high steady state loads as well as large impact loads, and withstand extreme cyclic loads combined with severe deflection. An object of the present invention is to provide an improved permanently inflated cushion device that has very good resistance to repeated applications.

Another object of the invention is to have a plurality of separation chambers inflated with gas so that changes in atmospheric pressure and temperature can increase the gas pressure in the chambers and cause small changes in their volume. without rupturing each chamber or cell,
An object of the present invention is to provide an elastomeric friction device that is highly durable, reliable, and has a long service life. In general terms, the cushion device of the present invention includes a pair of elastomeric, permeable sheets sealed at a desired distance to form a communicating or separating chamber, the chamber being filled with a gas or gas mixture at atmospheric pressure. or partially or completely filled or inflated to a predetermined pressure, which may be greater than atmospheric pressure.

The selected gas or gas mixture has a very low diffusivity through the permeable sheet to the outside of the chamber, and the ambient air has a relatively high diffusivity through the sheet to the inside of the chamber, so that the partial pressure of the air inside the chamber and the gas or The total pressure in the chamber, resulting from the sum of the partial pressures of the gas mixture, increases. The pressure of the gas or gas mixture initially placed in the chamber decreases at a very slow rate due to diffusion of such gas or gas mixture through the elastomer sheet, but the ambient air is more easily forced through the sheet. and diffuse into the chamber, resulting in a total pressure within the chamber greater than the initial expansion pressure of the gas or gas mixture. Although this total pressure within the chamber may decrease over time, it is still higher than the initial expansion pressure of the gas for an extended period of time and does not lose pressure very slowly over the following time, during which time the cushion device or still perform the shock absorption function. Cushion devices have applications outside of the cushion field.

This device is configured as a competition floor mat and can be used as a life preserver,
It can be shaped to function as a handle grip for a vibrating tool and as a shipping pallet placed between two rigid members. Other devices according to the invention are those that are subject to intermittent loading, such as permanently expanded cushions for use in place of permanently expanded foam padding in pillows and furniture.

When a person sits or sleeps on such a device, some of the air within the chamber diffuses outward from the chamber;
When the load is removed, air diffuses back into the chamber, automatically re-inflating the chamber and positioning it to properly receive the next load cycle. Other uses of the cushion device are discussed later in the specification. The invention has other advantages and objects that become more apparent from a consideration of some embodiments of its principles.

These forms are illustrated and described herein and in the accompanying drawings. It should be understood, however, that these forms are intended to be illustrative of the general principles of the invention and are not to be taken in a limiting sense. 1st, 2nd
In the form of the invention shown in the figures, two parts of the elastomeric material are
A segment of the cushioning device 10 is shown formed from two sheets 11, 12 with circular welds 13 to form separate spherical chambers 14 (e.g. formed by high frequency heat sealing techniques), the chambers being Elastomeric sheet material that is partially or fully expanded with a gas that has a low diffusion rate through the material.

The spherical chamber shown in FIG. 2 is obtained by providing a thin sheet of elastomeric material and inflating it to a relatively high pressure. In the one shown in FIG. 3, a thicker, higher modulus sheet is used which, when inflated to substantially the same pressure as the chamber shown in FIG. 2, forms an ellipsoidal shaped chamber 14a. If these chambers were inflated to a pressure lower than that used for the FIG. 2 chamber, ellipsoidal shaped chambers would also be formed in the case of the FIG. 2 sheet. As shown in FIGS. 4 and 5, two sheets of elastomeric material 11a, 12a are welded at circular locations 13a that space the chambers from each other and surround each chamber.

In one method of making the product of Figures 4 and 5, the top sheet 11a is first vacuum formed to form a dome-ended cylindrical chamber 14b before welding. While the vacuum is still applied, the top and bottom sheets are shaped in a circular pattern 13a.
Welded at A desired gas is then introduced into the chamber to form the cylindrical chamber 14b shown in FIG.
In the cushion device shown in FIGS. 6 and 7, the upper sheet 11b and the lower sheet 12b are arranged in a square pattern 1.
3b to form an ellipsoidal chamber 14c.

This square pattern in the weld area has a smaller overall weld area than the circular pattern of FIGS. 1 and 2, providing a more complete and uniform air bearing surface. In the cushion devices shown in Figures 8, 9 and 10, the weld areas 13c are provided in a rectangular pattern (Figure 8).

When pressurized, each chamber 14d becomes elongated (Figure 9) and has a circular cross section (Figure 10). Elastomeric materials that can be used to form cushion devices should have certain properties.

The first property is excellent heat sealability by various means, particularly the use of induction heat sealing techniques. This results in a high-strength, complete weld area that secures the sheets to each other, with high,
It is capable of withstanding steady-state stresses as well as long-term cyclic stress fluctuations and stress reversals that occur under severe dynamic loading conditions. The second property concerns appropriate physical properties such as tensile strength, modulus of elasticity, cleave, etc. The third property is a very low permeability to selected inflation gases/steams (hereinafter sometimes referred to as "supergases") and a fairly high permeability to air (N2O2). Another important factor in cushioning devices is the group of special gases/steams used to expand the sheet or film.

These gases/vapors are of a class that exhibits very low diffusivity in special elastomeric materials because they have very large molecules and very low solubility coefficients. The gas is inert, non-polar, and has a uniform/symmetrical, spherical, ellipsoidal (oblate or prolate) molecular shape or symmetrical branched molecular shape. These gases are non-toxic and
Non-flammable and non-corrosive to metals. They are excellent dielectric gases and liquids, have high levels of electron attachment and capture ability, and exhibit significantly reduced diffusivity in all polymers, elastomers and plastics (solid films). When special gases are used to inflate chambers made from these special elastomeric materials, the cushion device can maintain the initial inflation pressure for a very long time;
Almost no pressure loss occurs.

This is called "permanent" expansion. Permanent expansion is the result of a combination of two important factors: (1) the extremely low permeability of the supergas and the phenomenon of "two-pressure self-pressurization." Many tests were carried out over a five-year period. Re,
This confirmed that the diffusion rate of supergas in typical elastomer films is extremely low.

Most of the supergases tested were gases/vapors from the group consisting of: Namely, hexafluoroethane, sulfur hexafluoride, perfluoropropane, perfluorobutane, perfluoropentane, perfluorohexane, perfluoroheptane, octafluorocyclobutane, perfluorocyclobutane, hexafluoropropylene. , tetrafluoromethane, monochloropentafluoroethane, 1,2-dichlorotetrafluoroethane, 1,1,2-trichloro-1,2,2-trifluoroethane, chlorotrifluoroethylene, bromotrifluoromethane, Monochlorotrifluoromethane, monochlorodifluoromethane. Preferred gases/vapors are hexafluoroethane and sulfur hexafluoride. Most of the typical sheets or films tested were from the following group of materials:

Namely, polyurethane, polyester elastomer, fluoroelastomer, chlorinated polyethylene, polyvinyl chloride, chlorosulfonated polyethylene, polyethylene/
Ethylene Vinyl Acetate Copolymer, Neoprene, Butadiene Acrylonitrile Rubber, Butadiene Styrene Rubber, Ethylene Propylene Polymer, Natural Rubber, High Cassinoricone Rubber, Low Density Polyethylene, Adduct Rubber, Sulfide Rubber, Methyl Rubber, Butyl Rubber,
thermoplastic rubber.

Polyurethane is a preferred material. Most tests were conducted at relatively high pressure (20 psig) to accelerate the diffusion rate of the supergas and make the test preservative.

In many tests, after two years of testing, the pressure within the chamber still exceeded the initial inflation pressure. In all tests the pressure drop was very slow. At relatively low expansion pressures, from a few ounces to a few pounds per square inch, this time was extended at least five times (from two years to ten years).

Furthermore, in all tests the pressure was
During the month test, the initial inflation pressure actually increased considerably.
It is this pressure increase phenomenon that is referred to as "self-pressurization."
Self-pressurization is the result of the combination of the lower permeability of the special film or sheet with respect to resistance to the pressure of the supergas and the much higher permeability of the special film or sheet with respect to the passage of air. The air in the atmospheric environment surrounding the expansion chamber is such that the partial pressure of the air inside the chamber is equal to the partial pressure outside the chamber (i.e., 14.7 psia).
) into the chamber. The total pressure in each chamber is the sum of the air partial pressure and the supergas partial pressure. Since supergas does not exit while air is flowing in, a pressure rise of approximately 14.7 psi is possible within the constant volume chamber made from one of the elastomeric materials. FIG. 11 is a graph showing the pressure build-up within a typical elastomeric chamber of a packaging or cushioning device of the present invention, where the chamber was initially pressurized to 1.0 psig with one of the supergases, such as Freon 116. . As shown, pressures range from 1.0 psig to 6.5 p8 after 6 weeks.
It increased to 1g (curve 1). Although the chamber was stretched during the test and its volume increased by approximately 40%, this was only 65
0% pressure increase. If the volume remained constant, the total pressure would have increased to 15.2 psig for this particular supergas, as shown in curve 2.

When the cushion device is used as a packaging material, each pressurized chamber has a low pressure, typically 2.0 ps.
It is inflated to act below ig. Therefore, it is necessary to alleviate the pressure increase caused by self-pressurization. This is done by inflating the chamber with a mixture of air and supergas. As shown by curve 1 in FIG. 12, a mixture of 25% supergas and 75% air in the elastomer chamber causes only a pressure rise of 1.0 to 2.2 degrees. 25-75%, 50-50%
The pressure rise in a constant volume chamber with a 100-0% supergas-air mixture is also shown in FIG.

The pressure rise is further reduced if the pressure chamber is not expanded to its full volume during the initial expansion and is in a wrinkled state immediately after expansion.

When the self-pressurizing pressure rise occurs, the chamber volume expands and the supergas pressure drops. The key to this approach is to ensure that the supergas partial pressure reaches the design pressure when the chamber is fully expanded. Ambient air passes through the elastomeric film and enters the chamber, increasing the pressure inside it. That is, the partial pressure of air is added to the partial pressure of supergas to produce a total pressure greater than zero Psig. However, since the chamber is initially in a wrinkled state, the volume of the chamber expands and this expansion continues due to self-pressurization until the final volume of the chamber is reached. When a stable state is reached and the internal pressure is, for example, 1/2 ps
It takes several weeks to become ig. The inward diffusion of ambient air to reach a steady state is referred to as "aging."
After aging, the pressure in the chamber becomes the sum of the atmospheric pressure of the air (14.7 psia) and the partial pressure of the supergas.

It is the partial pressure of the supergas that raises the gauge pressure in the chamber and maintains it above zero. If there is no supergas in the chamber, the chamber will contain 100% air and the device will not function properly. When loaded during use, air is squeezed out of the chamber and the cushion device flattens because no barrier material is used as with other packaging materials. Therefore, it is the supergas that gives the device its permanent expansion properties, and the device must contain a sufficient amount of supergas in the gas mixture to function properly throughout its useful life. Therefore, the pressure within the device must be at least slightly higher than atmospheric pressure, with the specific pressure depending on the design loading conditions. From a manufacturing standpoint, it is desirable to fill the chamber with gas at atmospheric pressure.
This can be done because there is a self-pressurization phenomenon. After manufacturing is complete, self-pressurization automatically increases the pressure to a level above atmospheric pressure during the aging process. As previously mentioned, it is the relatively small amount of supergas within the device that gives the device its permanent expansion properties and allows it to be used under heavy loads for very long periods of time with little pressure loss. be. The cost of the cushion device is reduced by using a minimum amount of supergas and a maximum amount of air. The optimum amount of supergas is cycle dependent. Heavy loads require higher concentrations of supergas. The above can be explained by the fact that when a load is applied, the cushion device compresses somewhat and the pressure of the supergas and air increases enough to support the load.

Since the air pressure is above atmospheric pressure, the air gradually diffuses out of the chamber under load. Supergas does not diffuse out. As long as the load is applied, air continues to slowly diffuse out of the chamber, slowly compressing the chamber and reducing its volume, thereby increasing the pressure of the supergas. The sum of the air partial pressure and the supergas partial pressure is always sufficient to support the load, causing the air pressure to drop and the supergas pressure to rise. If the load is applied continuously for an extended period of time (e.g., 3-4 months at normal load), a final state is reached in which the partial pressure of the air is reduced to a minimum value, i.e., 14.7 psia (atmospheric pressure). At this time the supergas pressure is at its highest value. The diffusion process has stabilized and the gas no longer diffuses. When the load is removed, the self-pressurization phenomenon occurs again and the air diffuses inward, returning the pressure in the chamber to its original unloaded state.

Therefore, the cushion device has self-compensating and self-healing properties. In normal use, the load will not last long enough to approach the final state described above. However, it is preferable that the device continue to function properly even under worst-case conditions, such as "BOttOming-0ut". In order to prevent the chamber from bottoming out, the chamber must contain a sufficient amount of supergas in the unloaded state, so that even in the worst case conditions (when the air volume is reduced to a minimum) the chamber still contains a suitable amount of gas. should be. The self-healing or self-reinflating properties of cushion devices are applicable to intermittent loaded devices such as permanently expanded pillows and cushions used in place of foam padding as upholstery in furniture.

A relatively small amount of supergas is required in the air-supergas mixture within the chamber to support the load. Air diffuses outward while a person is sitting on a cushion or inflatable furniture, but when the load is removed (especially at night)
The air diffuses back into the pillow or cushion and the cushion automatically reinflates and is ready for the next load cycle. Changes in altitude affect elastomeric devices.

At high altitudes, the ambient pressure is low and the difference between the pressure inside the chamber and the pressure outside it is much greater than at sea level. In the case of prior art barrier material shaped products, when the gear pin is installed in an aircraft where the pressure is typically around 5,000 to 8,000 feet altitude, the air chamber can expand significantly and rupture. In the case of the elastomeric product according to the invention, increased pressure does not adversely affect performance due to the excellent physical properties and integrity of the weld.

If left at high altitude, as occurs in Denver, Colorado, the air within the chamber will quickly diffuse outward and the product will return to its initial expanded state. Correspondingly, as the cushion device descends to low altitude or sea level, ambient air will diffuse into the chamber. Applications for cushioning devices outside of the industrial packaging field are lightweight, durable cushioning members for footwear, such as ski boots and shoe-shaped skates such as shoe skates and roller skates.

The permanently expanded product is shaped to enclose the foot and lower leg and is used as an improved cushioning member to replace foam padding in footwear. Another use for cushion devices is as a permanent inflation tank that fits over the top of the foot. Permanently inflated cushion devices can be used as shoe insoles or liners, overcoming the drawbacks of conventional products and providing better elasticity, shock absorption and greater cold insulation.

Another use for the cushion device of the present invention is in door and window seals, where it can be used in place of prior art extruded rubber or foam plastic strips.

After a period of use, the foam loses its shape and elasticity and ceases to function. The seal according to the present invention is No. 8 to 1.
It is constructed from an elongated, rectangular chamber as shown in Figure 0, cut and pieced to the appropriate width and length for the particular sealing application. The elastomeric device of the present invention can also be used as a permanent expansion liner between the helmet shell and the wearer's head. Shock absorption properties are extremely advantageous in helmets used for activities such as football and motorcycling. If these helmets are designed with a rigid (but lightweight) outer shell used with a permanent expansion liner, extremely severe impact loads of 1500 G or more can be attenuated to 125 G or less. U. S. DepartmentOfTr
Motorcycle helmets were tested according to the anspOrtatiOn procedure. In these tests, a helmet with a simulated head is dropped from a height of approximately 8 feet onto a steel hemispherical anvil. Depar
The tmentOfTranspOrtatiOn standard requires that the maximum impact not exceed 800G for 2 milliseconds. The cushion liner according to the present invention meets this standard and has considerable margin. As far as is known, other helmets do not meet this standard as well as the one according to the invention. Similarly, cushion devices can be constructed and used as pads for athletic equipment, such as shoulder pads, kidney pads, and leg pads for football, and pads for other sports, such as shoulder pads, baseball, etc. can.

[Brief explanation of drawings]

FIG. 1 is a plan view of a portion of a cushion or shock absorbing device according to the present invention. FIG. 2 is a sectional view taken along line 2-2 in FIG. 1. Figure 3 is the second
Figure 2 corresponds to Figure 2 of a cushion device made from a thicker elastomeric material than that shown; FIG. 4 is a plan view of another embodiment of a cushion or shock absorbing device. FIG. 5 is a sectional view taken along line 5-5 in FIG. 4. FIG. 6 is a plan view of yet another embodiment of a cushion or shock absorbing device. FIG. 7 is a sectional view taken along line 7-7 in FIG. 6. FIG. 8 is a plan view of yet another embodiment of a cushion or shock absorbing device. Figure 9 is the 8th
It is a sectional view taken along line 9-9 in the figure. Figure 10 is from 10 in Figure 8.
10 is a sectional view taken along line 10. FIG. 11 is a graph illustrating the self-pressurization of an elastomeric chamber due to back-diffusion of air into the chamber. FIG. 12 is a graph showing the pressure increase due to self-pressurization of the elastomer chamber by different mixtures of air and other gases initially present in the chamber. 10
...Cushion device, 11, 12...
... Elastomer sheet, 13 ... Welding area, 14 ... Chamber.

Claims (1)

[Claims] 1. A cushion device in which a gas is sealed in chambers provided independently in a laminated elastomer sheet material, wherein the sheet material has low permeability to the sealed gas and the surrounding area surrounding each chamber is low. It is composed of a plain material that is highly permeable to the air, and the filled gas is inert,
Using a non-polar, large molecular gas, the pressure of the filled gas ensures a minimum volume in each chamber, and air can flow in and out of the chamber by expanding and contracting the chamber caused by external factors. An elastomeric cushion device for products and objects characterized by: 2 The gas is hexafluoroethane, sulfur hexafluoride, perfluoropropane, perfluorobutane, perfluoropentane, perfluorohexane, perfluoroheptane, octafluorocyclobutane, perfluorocyclobutane, hexafluorocyclobutane, Fluoropropylene, tetrafluoromethane, monochloropentafluoroethane, 1/2
- dichlorotetrafluoroethane, 1,1,2-trichloro-1,2,2trifluoroethane, chlorotrifluoroethylene, bromotrifluoromethane, and monochlorotrifluoromethane; Elastomeric cushion devices for products and objects according to scope 1. 3. The elastomer sheet material is polyurethane, polyester elastobutyl rubber, fluoroelastomer, chlorinated polyethylene, polyvinyl chloride, chlorosulfonated polyethylene, polyethylene/ethylene vinyl acetate copolymer, neoprene, butadiene acrylonitrile rubber, butadiene styrene rubber, ethylene propylene polymer natural The elastomeric cushioning device for products and objects of claim 1 selected from the group of materials consisting of rubber, high strength silicone rubber, low density polyethylene, adduct rubber, sulfide rubber, methyl rubber, and thermoplastic rubber. 4 The elastomer sheet material is polyurethane, polyester elastomer, butyl rubber, fluoroelastomer,
Chlorinated polyethylene, polyvinyl chloride, chlorosulfonated polyethylene, polyethylene/ethylene vinyl acetate copolymer, neoprene, butadiene acrylonitrile rubber, butadiene styrene rubber, ethylene propylene polymer, natural rubber, high strength silicone, rubber, low density polyethylene, adduct rubber, sulfide Elastomeric cushioning device for products and objects according to claim 1, selected from the group of materials consisting of rubber, methyl rubber and thermoplastic rubber. 5. The elastomeric cushioning device for articles and objects of claim 1, wherein said chamber is spherical. 6. Claim 1, wherein the chamber is ellipsoidal.
Elastomeric Cushion Devices for Products and Objects Listed in Section. 7. The elastomeric cushioning device for articles and objects of claim 1, wherein said chamber is generally cylindrical. 8. The elastomeric cushioning device for articles and objects of claim 1, wherein each said chamber has a substantially square section. 9. The elastomeric cushioning device for articles and objects of claim 1, wherein each chamber has a rectangular portion. 10. The elastomeric cushion device for products and objects according to claim 1, wherein each of the chambers has a rectangular portion, and the chambers are arranged in a grid-like arrangement with shifted positions. 11. The elastomeric cushion device for products and objects according to claim 1, wherein the elastomeric sheet material is an ether polyurethane. 12. The elastomeric cushioning device for articles and objects of claim 1, wherein said chamber is partially collapsed when inflated to said initial value with said gas. 13. The elastomeric cushioning device for articles and objects of claim 7, wherein said chamber is partially collapsed when inflated to said initial value with said gas. 14. An elastomeric cushioning device for articles and objects according to claim 1, wherein the laminated elastomeric sheet material is sealed to each other at spaced apart circular welded areas to form a spherical chamber upon expansion of the chamber. . 15. The elastomeric cushion for articles and objects of claim 1, wherein said elastomeric sheet material is sealed to each other at spaced apart circular welded areas to form an ellipsoidal shaped chamber upon expansion of said chamber. device. 16. The elastomer for articles and objects of claim 1, wherein said elastomeric sheet material is sealed to one another at spaced apart circular welded areas to form a generally cylindrical chamber upon expansion of said chamber. cushion device. 17. The elastomeric sheet material is sealed to each other at spaced apart weld areas to form generally dome-shaped chambers, each chamber having a substantially square portion in the weld area. Elastomeric cushion devices for products and objects. 18. The elastomeric sheet material is sealed to each other at spaced apart welded areas to form generally arcuate chambers, each chamber having a substantially rectangular portion in the welded area. Elastomeric cushion devices for products and objects. 19. The elastomeric cushioning device for articles and objects of claim 14, wherein said chamber is partially collapsed when inflated to said initial value with said gas. 20. The elastomeric cushioning device for articles and objects of claim 15, wherein said chamber is partially collapsed when inflated with said gas to said initial value. 21. The elastomeric cushioning device for articles and objects of claim 16, wherein said chamber is partially collapsed when inflated with said gas to said initial value. 22. Elastomeric cushioning device for articles and objects according to claim 1, wherein the pressurized gas expanding to a predetermined initial value is diluted with air to form an initial chamber expansion mixture having a pressure above atmospheric pressure. . 23. The elastomeric cushion for articles and objects of claim 1, wherein the ambient air diffuses into the chamber through the sealing member and increases the pressure within the chamber above the initial value. device.