Protective Gear With Hydraulic Liner

Abstract

Protective gear such as head gear for use in sports, industry, and the military, etc. includes a one-piece molded protective outer shell such as a helmet shell with a hydraulic energy absorbing liner which has an array of interconnected compressible vinyl walled compartments arranged around a central crown compartment with shock and energy dissipating fluid in the interconnected compartments. Each of the compartments is provided with a porous insert or surge mitigator of open-celled foam, which throttles fluid flow within the compartments as the compartments are compressed and deformed upon impact, thus to absorb or dissipate energy. The porous inserts also prevent sloshing of fluid and retain some fluid in the compartments at all times, preventing complete collapse of one or more compartments during impact. In preferred embodiments, the fluid includes hydraulic liquid.

Description

BACKGROUND OF THE INVENTION

Various types of impact absorbing safety head gear have been developed in which hydraulic fluid filled compartments are employed to dissipate the energy of an impact. Simpson U.S. Pat. No. 3,039,109, Cade et al., U.S. Pat. No. 3,600,714, and Morgan U.S. Pat. No. 3,609,764 are illustrative of safety helmets which employ innerconnected cells or compartments arranged around the interior of the helmet with a contained hydraulic fluid. Upon impact, the fluid in the liners of these helmets is squeezed from a deformed or compressed compartment into an adjacent compartment. Relatively small diameter innerconnecting passageways between the compartments obstruct fluid flow between the compartments and cause a drop in pressure of the fluid as it is squeezed through the passageways, resulting in performance of work and absorption of energy.

The fluid cell liners typified by the foregoing patents have certain disadvantages which include the danger of complete loss of fluid from one or more compartments caused by a rupture of one cell or compartment and the resulting complete collapse of the compartment. The bottoming or complete collapse of a cell can result in loss of protection in the zone of the collapsed cell and consequent risk of injury to the wearer of the head gear.

Other problems inhering in prior art head gear with hydraulic fluid liners include noticeable and distracting fluid noises caused by sloshing of the fluid in the cells, unequal distribution of fluid in the cells caused by gravity migration of fluid, excessive head gear weight caused by complete filling of the cells with liquid, etc.

SUMMARY OF INVENTION

The difficulties and problems associated with prior art helmets having a hydraulic fluid energy absorbing system with a plurality of interconnected cells are avoided in the present invention by the use of surge mitigators in the form of reticulated foam or like inserts which materially fill the space enclosed within the interconnected liquid containing cells or compartments and provide internally within each insert a multiplicity of liquid passages and liquid obstructions. Hence each compartment has a self-contained hydraulic energy absorbing system which functions both independently of the like systems in adjacent cells and in cooperation with the like systems in adjacent cells. The surge mitigators throttle fluid flow within a cell and between cells and prevent rapid, and complete hydraulic fluid evacuation from any of the compartments as a result of impact. The foam inserts also act as pumps to restore hydraulic fluid to a cell after compressive force thereon has been released.

In a preferred embodiment, reticulated open-celled polyurethane foam inserts provide a throttling action to hydraulic fluid flow within the compartments. This throttling action causes a fluid pressure drop and consequent substantial energy absorption within the individual compartments as well as absorption of energy as the fluid is squeezed through the small passageways interconnecting the compartments. Inasmuch as the preferred arrangement includes surge mitigators in each of the fluid compartments, and the surge mitigators substantially occupy the included space within the undeformed fluid compartments, the porous inserts in adjacent compartments obstruct flow of fluid through the passageways into the adjacent compartments.

In addition, the porous inserts or surge mitigators damp liquid flow noise of sloshing within the compartments during use and retain sufficient liquid in a compartment even when the compartments are substantially deformed to prevent complete collapse or bottoming of a compartment and thus loss of energy absorbing capability which can occur in prior art hydraulic liners.

Further objects, advantages and features of the invention will become apparent from the following disclosure.

DRAWINGS

FIG. 1 is an exploded view of a football helmet shell with an intermediate sizing liner and a multi-compartment hydraulic liner or suspension with surge mitigators in the liner compartments, in accordance with the invention.

FIG. 2 is a developed plan view of the hydraulic liner shown in FIG. 1.

FIG. 3 is an enlarged fragmentary sectional view of an assembly of the parts shown in FIG. 1.

FIG. 4 is an enlarged fragmentary perspective view of a portion of the hydraulic liner shown in FIGS. 1, 2 and 3 showing the hydraulic fluid inlet valve.

FIG. 5 is an enlarged sectional view along line 5--5 of FIG. 2.

FIG. 6 is a perspective view of a surge mitigator.

Although the disclosure hereof is detailed and exact to enable those skilled in the art to practice the invention, the physical embodiments herein disclosed merely exemplify the invention which may be embodied in other specific structure. The scope of the invention is defined in the claims appended hereto.

The protective gear of the invention can be employed in all types of protective gear and especially head gear for sports, industry, military, etc. For exemplification, the invention is illustrated as embodied in a football helmet 10 which includes a one-piece molded helmet shell 12 (FIG. 1) made of an impact resistant plastic such as Cycolac, a sizing liner 16 and a hydraulic liner or suspension 50 provided with hydraulic fluid compartments containing foam inserts or surge mitigators 89. When properly fitted with sizing liners 16, all portions of the inside surface of the helmet are desirably at the same approximate distance from the skull to dispense shock loads.

The sizing liner 16 is desirably made of a firm but resilient plastic foam such as Ensolite to provide additional protection. Sizing liners of various thicknesses are utilized to achieve proper fitting of the helmet for each user. The helmet shell can also be constructed in various standard head sizes. The sizing liners 16 have four radially projecting segments 18, 20, 22 and 24 (FIG. 1) which diverge or increase in area radially outwardly from a central hub portion 26. When assembled in the helmet shell 12, the adjacent edges of the segments 21, 23 abut to thus provide substantially complete coverage of the inside surface area of the helmet and the area of the helmet covering the wearer's head. The sizing liner 16 is detachably secured to the inside surface of the helmet with front and rear soft vinyl snubbers 28 and 30 (FIG. 3) which have a hooked or U-shaped terminal extremity 32 which receives the margin 27 of the liner 16 and securely engages the lower margin 34 of the helmet. Tabs 31 on vinyl snubbers 28, 30 are glued or otherwise attached to the liner 16. Mating tape tabs such as Velcro tabs 33 can also be employed to connect with complementary tabs adhered to the inside surface of the helmet shell 12.

The liner 16 is also provided with a plurality of tape tabs 42 arranged around the radially extending segments 18, 20, 22, 24 for detachable engagement with mating tape tabs 44 on the hydraulic liner when the hydraulic liner 50 is assembled in the helmet shell 12. Tape tabs 42, 44 are desirably formed of complementary Velcro fastener elements.

The exemplified hydraulic liner or suspension 50 of the invention includes an assembly of four radially extending multi-compartment segments 60, 62, 64 and 66 (FIG. 2) with each of the segments including three compartments 68, 70 and 72. The multi-compartment segments diverge or increase in area radially outwardly from a central or crown compartment 73 and are complementary to the shape of the segments 18, 20, 22, 24 of the sizing liner. The segment 62 which spans the inside of the rear 75 of the helmet shell 12 is desirably larger in size than the other segments, thus to cover the larger rear helmet area. The individual compartments in each segment are arranged around central openings 76 and are interconnected by fluid passages 78. The compartments 72 adjacent the central or crown compartment 73 are interconnected with the central compartment 73 by fluid passages 82.

The compartments in the liner 50 are desirably vacuum formed from one sheet of tough vinyl plastic 71 laminated to a flat backing sheet 81 of like tough vinyl plastic (FIG. 5) by heat sealed seams 79 around the compartments and passageways 78. The crown compartment 73 is provided with a vinyl valve assembly 83 (FIG. 4) for introduction of a hydraulic fluid. The valve assembly 83 is heat sealed to the wall 84 of the compartment 83 and includes a valve member or plug 85 having an annular groove 86 which snaps into the internal shoulder 87 in the fill tube 99 to seal the crown compartment 73 when the valve plug and tube 99 are pressed together. This valve is self-closing under pressure from within compartment 73. A pull tab 91 facilitates separation of the plug 85 from the shoulder 87 to open the valve. The wall 84 which carries the valve 83 is located against the sizing liner 16 when the liner 16 and the liner 50 are assembled in the helmet to prevent accidental opening of the valve without disassembly of the liners. When the valve 83 is closed, the entire valve assembly except for the tab 91 are recessed beneath the surface 84.

A hydraulic fluid with a low freezing temperature such as a mixture of Propylene Glycol and water is contained in the compartments. The viscosity of this fluid is not substantially different from that of water. In a practical embodiment when sixteen fluid ounces of liquid are utilized in the suspension, this quantity consists of eight fluid ounces each of water and Propylene Glycol, the same being completely miscible.

In accordance with the invention, each of the hydraulic fluid compartments in the hydraulic liner 50 is provided with hydraulic fluid surge mitigating and hydraulic fluid and energy absorbing means for retaining the hydraulic fluid and for impeding and throttling hydraulic fluid flow within the compartments and between compartments, thus to dissipate energy caused by an impact on the helmet and deformation or compression of one or more compartments. In the disclosed construction, the hydraulic fluid surge mitigating means comprises reticulated open-celled foam inserts 89 which as shown in FIGS. 2 and 6 have a configuration complementary to the configuration of the cell and substantially completely occupy the volume of the interiors of the compartments. The open-celled reticulated polyurethane foam described in Volz U.S. Pat. No. 3,171,820 and marketed as Scott Industrial Foam has been successfully utilized. This foam is available in various specified porosities or pores per linear inch. Other desirable characteristics of this foam include flexibility, compressibility, light weight and high fluid permeability with uniform porosity. An insert porosity of 80 pores per linear inch has provided the desired regulated flow characteristics.

The surge mitigators or foam inserts 89 internally provide a multiplicity of fluid passages and fluid obstructions which throttle hydraulic fluid flow within the cell to cause a pressure drop resulting in energy absorption or dissipation within compartments. The foam inserts also prevent complete evacuation or loss of hydraulic fluid from a particular compartment and thus prevent bottoming out or complete collapse of the compartment or cell and thus loss of energy absorbing capability which can occur with prior art hydraulic liners. Moreover, the foam inserts prevent sloshing of hydraulic fluid within the compartments and the disturbing noise associated with the sloshing of hydraulic fluid.

The hydraulic fluid retaining characteristics of the foam inserts are such that even if a compartment ruptures, the hydraulic fluid loss from the ruptured compartment is minimal.

In addition to providing for primary absorption or dissipation of energy within the compartments, the passageways 78 and 82 provide obstructions to hydraulic fluid flow between the compartments for a secondary energy absorption stage. The hydraulic fluid surge mitigators in adjacent compartments also obstruct flow between the compartments. For instance, if the compartment 70 (FIG. 5) is compressed and hydraulic fluid is squeezed through the passageway 78 in the direction of arrow 97, the surge mitigator 89 in compartment 68 will obstruct flow at 92 of hydraulic fluid moving through passageway 78.

The preferred foam has a density of about 0.2 lbs./cu. ft. Hence it is very light in weight. The pores are so numerous that the skeletal structure of the strand material of the foam occupies only about 3 percent of the foam volume, thus leaving about 97 percent of void space available for fluid retention. The absorptive capacity of the foam is so great that even if a chamber is ruptured, there will only be a loss of five percent or less of the hydraulic fluid, the balance remaining absorbed in the foam insert.

Utilization of the foam inserts makes it possible to reduce the amount of liquid in the suspension without loss of energy absorptive capability. This reduces the weight of the suspension below what would be required in the absence of the surge mitigators and reduces fatigue and annoyance otherwise experienced by the wearer.

The fluid suspension of the present invention contains air, hydraulic fluid and the foam surge mitigators. In a practical embodiment of the invention, the percentage mixture for a football helmet suspension containing sixteen fluid ounces of hydraulic fluid is as follows:

Hydraulic fluid 65% Air 30% Foam insert (less void space) 5%

In the football helmet suspension above mentioned, measured volumes were as follows:

Total internal volume of hydraulic cell envelopes 724.4 milliliters Total volume of hydraulic fluid within the envelope 473.16 milliliters Total volume of air within the envelope 216.4 milliliters Total volume of foam insert (excluding void space) 34.84 milliliters

Accordingly, the hydraulic fluid is a major component of the ingredients in said embodiment and occupies in excess of one-half of the total available space.

This mixture has proven highly satisfactory but may not be optimum. Variations from the foregoing percentages will also be useful. Reductions of the percentage of hydraulic fluid from the indicated amount will reduce the quantity of hydraulic fluid which can react to impact and move from one pressure zone to another and hence will reduce pro rata the cushioning and energy absorbing capacity of the system. Increase of the percentage of hydraulic fluid from the indicated amount will reduce the void or free space within the suspension and hence will slow the rate of migration of the fluid within any one compartment and from one compartment to another, thus also reducing pro rata the cushioning and energy absorbing capacity of the system. Accordingly, the foregoing mixture percentages are given as an example only, as other mixture percentages will likewise have beneficial results. A universal optimum percentage mix has not been established, as this will vary according to helmet size and the particular use to which the helmet or other gear is to be put. It is believed, however, that the percentage mixture above stated is nearly optimum for a standard football helmet.

Certain aspects of the particular shape and configuration of the hydraulic suspension 50, as illustrated in FIG. 2, are also believed to be advantageous. Each segment 60, 62, 64, 66 has but a single channel 82 connecting it to the control compartment 73. Accordingly, flow of hydraulic fluid out of any such segment and migration of fluid to the control compartment and thence to other segments is restricted.

Gravity will tend to cause the hydraulic fluid to drop to the bottom of the respective compartments. The effects of gravity are counteracted by the absorptive capacity of the surge mitigators 89 which hold the fluid in suspension within the compartments against the force of gravity.

Accordingly, the surge mitigators tend to stabilize the hydraulic fluid in approximately equal amounts in each compartment where it is instantly available for impact and shock absorption, regardless of the altitude of the helmet or position of the wearer. Moreover, the foam inserts act as pumps to restore hydraulic liquid to a cell from which the liquid may have been squeezed, as the foam inserts resiliently expand.

The channels 82, 78 are formed adjacent wall 81 (FIG. 5) of the suspension. Accordingly, when the suspension is oriented in the helmet with wall 81 uppermost, as shown in FIG. 3, the channels 82, 78 will be uppermost, thus trapping hydraulic fluid in sump portions of the compartments therebelow. This arrangement also restricts transfer of liquid from one chamber to another and helps stabilize an even distribution of the liquid throughout the suspension.

While the invention is primarily intended for use with head gear, it is also applicable to other protective gear such as shoulder pads, shin guards, knee pads, etc.

Claims

We claim:

1. Protective gear comprising an outer shall, a hydraulic liner for said shell having an array of interconnected collapsible hydraulic fluid containing compartments, hydraulic fluid in said compartments, the interconnection of one compartment with another allowing displacement of hydraulic fluid from a deformed compartment to other compartments in said array, deformable highly porous hydraulic fluid surge mitigating means having substantial void space in said compartments for throttling hydraulic fluid flow within a compartment and between said interconnected compartments caused by deformation of said compartment and to dissipate and absorb the energy causing the deformation and to retain hydraulic fluid in the deformed compartment regardless of the displacement of some hydraulic fluid to other compartments.

2. Protective gear in accordance with claim 1 wherein said surge mitigating means comprises reticulated inserts providing a multiplicity of hydraulic fluid passages and obstructions to hydraulic fluid flow which causes a pressure drop during movement of hydraulic fluid within the insert.

3. Protective gear in accordance with claim 2 wherein said porous insert is constructed of open-celled foam.

4. Protective gear in accordance with claim 3 wherein said foam is a polyurethane resin.

5. Protective gear in accordance with claim 1 wherein said array includes forward, rear and side arrays of compartments arranged around a crown compartment and means defining hydraulic fluid passages interconnecting each of said compartments in each of said arrays and interconnecting each array with said crown compartment.

6. Protective gear in accordance with claim 1 in which said compartments also contain air.

7. Protective gear in accordance with claim 1 in which the fluid volume occupied by the hydraulic fluid is in excess of one-half of the total available space within said array.

8. Protective gear in accordance with claim 1 wherein said hydraulic fluid surge mitigating means substantially occupies the volume of said compartment.

9. Protective gear in accordance with claim 1 including an intermediate sizing liner between said hydraulic liner and said shell.

10. Protective head gear comprising an outer covering, an energy absorbing liner for said covering including an array of fluid compartments, hydraulic fluid in said compartments, fluid passages interconnecting adjacent compartments to allow displacement of hydraulic fluid from a deformed compartment to other compartments in said array and deformable highly porous means having substantial void space occupying the major portion of the volume of each of said compartments to provide a controlled resistance to movement of hydraulic fluid within said compartment and between said compartments and to retain a quantity of hydraulic fluid in said compartments during use of the head gear nothwithstanding substantial deformation of a compartment due to impact and the tendency of hydraulic fluid to be displaced from said deformed compartment.

11. Protective head gear in accordance with claim 10 in which said fluid compartments also contain air.

12. Protective head gear in accordance with claim 11 in which the air comprises less than one-half and the hydraulic fluid comprises in excess of one-half of the total available space within said compartments.

13. Protective head gear comprising an outer shell shaped to receive a wearer's head, an energy absorbing liner for said shell comprising an array of interconnected deformable compartments, the interconnection of one compartment with another allowing displacement of hydraulic fluid from a deformed compartment to other compartments in said array, hydraulic fluid in said compartments, and deformable highly porous resilient hydraulic fluid surge mitigating means having substantial void space materially filling the space within said compartments, said means providing a plurality of fluid orifices and flow obstructions to cause energy dissipating pressure losses upon movement of the hydraulic fluid through said orifices and around said obstructions as a result of deformation of said compartments, said surge mitigating means retaining hydraulic fluid in a deformed compartment regardless of the displacement of some hydraulic fluid to other compartments.

14. Protective head gear in accordance with claim 10 in which said array includes compartments at opposite sides of the wearer's head, whereby hydraulic fluid displaced from a deformed compartment at one side of the wearer's head will migrate through said fluid passages to a compartment at the other side of the wearer's head.

15. Protective head gear in accordance with claim 13 in which said array includes compartments at opposite sides of the wearer's head, whereby hydraulic fluid displaced from a deformed compartment at one side of the wearer's head will migrate through said fluid passages to a compartment at the other side of the wearer's head.