U.S. patent number 3,713,640 [Application Number 05/058,462] was granted by the patent office on 1973-01-30 for energy absorbing and sizing means for helmets.
This patent grant is currently assigned to Riddell, Inc.. Invention is credited to Gerard E. Margan.
United States Patent |
3,713,640 |
Margan |
January 30, 1973 |
ENERGY ABSORBING AND SIZING MEANS FOR HELMETS
Abstract
A system for absorbing energy to avoid the detrimental effects
of impacts in protective equipment such as helmets comprising a
plurality of first chambers located on the inside surface of the
helmet for positioning adjacent the head of the wearer. A
substantially non-compressible fluid is included within these first
chambers, and conduits connect the first chambers with
corresponding second chambers. Upon impact, fluid is displaced to
the second chambers, and, due to the design of the chambers, the
displaced fluid is returned to the first chambers when the force of
the impact is removed. Sizing means useful with the energy
absorbing means or in other applications are located on the
interior of the helmet surface. The sizing means include expandable
compartments, and valves are associated with these compartments
whereby a user of the helmet can place the helmet on his head after
which air is introduced into the compartments until a proper fit is
achieved. Energy absorbing pads are preferably located within the
compartments to serve as additional safeguards under high impact
conditions.
Inventors: |
Margan; Gerard E. (Lake Forest,
IL) |
Assignee: |
Riddell, Inc. (Des Plaines,
IL)
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Family
ID: |
22016947 |
Appl.
No.: |
05/058,462 |
Filed: |
July 27, 1970 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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808800 |
Mar 20, 1969 |
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457016 |
May 19, 1965 |
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664748 |
Aug 31, 1967 |
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Current U.S.
Class: |
267/117;
2/413 |
Current CPC
Class: |
F16F
13/06 (20130101); A42B 3/122 (20130101) |
Current International
Class: |
A42B
3/04 (20060101); A42B 3/12 (20060101); F16F
13/06 (20060101); F16F 13/04 (20060101); F16f
009/10 () |
Field of
Search: |
;269/117 ;206/46 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Marbert; James B.
Parent Case Text
This is a division of my copending application Ser. No. 808,800,
filed on Mar. 20, 1969, which application was a
continuation-in-part of application Ser. No. 457,016, filed on May
19, 1965, and now abandoned, and application Ser. No. 664,748,
filed on Aug. 31, 1967 and also now abandoned.
Claims
That which is claimed is:
1. An assembly comprising a plurality of interconnected fluid
containing compartments mounted on a common backing, valve means
communicating with said compartments for introducing and removing
fluid to thereby permit changing of the size of the compartments,
and energy absorbing means associated with said compartments, said
energy absorbing means comprising a plurality of first flexible
chambers, a plurality of second flexible chambers, passage means
connecting said first chambers to said second chambers, a
substantially non-compressible fluid within said first chambers,
and means normally retaining said second chambers in a compressed
state whereby at least a major portion of said fluid will normally
be retained in said first chambers and whereby the force of an
impact applied to said first chambers operates to transfer fluid
through said passage means into said second chambers with said
fluid moving back to the first chambers when the force is removed,
and wherein combinations of first and second chambers are located
on said backing between adjacent compartments.
2. An assembly in accordance with claim 1 wherein said sizing means
and energy absorbing means are formed from two opposing sheets of
heat sealable material, one of said sheets providing said common
backing, said sheets being heat sealed together around the
peripheral edges of said compartments and around the peripheral
edges of said first and second chambers, the passage means between
said first and second chambers being formed by leaving a narrow
unheat-sealed area between said chambers, and wherein additional
passage means are provided for interconnecting said compartments by
leaving narrow unheat-sealed areas extending between the respective
compartments.
3. An assembly in accordance with claim 2 wherein said second
flexible chambers are provided by leaving an unheat-sealed area
between substantially co-extensive portions of the respective
sheets whereby a minimum amount of said non-compressible fluid can
be normally received in the second chambers, and wherein said first
chambers are provided by heat sealing an area of one sheet of
substantially greater size than the attached area of the other
sheet whereby a substantially larger amount of said
non-compressible fluid can be normally maintained in said first
chamber.
4. In a construction adapted to absorb energy when subjected to
impact, the improvement comprising a plurality of first flexible
chambers positioned on the surface of the construction to receive
the effects of said impact, a plurality of second flexible
chambers, passage means connecting said first chambers to said
second chambers, a substantially non-compressible fluid within said
first chambers, said second chambers being formed by substantially
overlying walls secured at their edges whereby the second chambers
are normally maintained in a compressed state of low volume so that
substantially all of said fluid will normally be retained in said
first chambers, the force of an impact being adapted to transfer
fluid through said passage means into said second chambers, and
whereby the fluid transferred is moved back to the first chambers
when said force is removed.
5. In an assembly for use in absorbing energy when subjected to
impact, the improvement comprising a plurality of first flexible
chambers adapted to receive the effects of said impact, a plurality
of second flexible chambers, passage means connecting said first
chambers to said second chambers, a substantially non-compressible
fluid within said first chambers, at least a major portion of said
fluid normally being retained in said first chambers, the force of
the impact operating to transfer fluid through said passage means
into said second chambers, and whereby fluid is moved back to the
first chambers when said force is dissipated, and including a
plurality of sizing means attached in said assembly, and means for
adjusting the size of said sizing means to permit use of the
assembly under varying conditions.
6. In an assembly for use in absorbing energy when subjected to
impact, the improvement comprising a plurality of sizing means,
said sizing means comprising compartments having a compressible
fluid disposed therein, valve means communicating with said
compartments for introducing and removing said fluid to thereby
permit changing of the size of said compartments, and energy
absorbing means having energy absorbing capabilities completely
independent of said compartments and having exposed exterior
surfaces for receiving applied force when impact occurs, said
compartments being located at spaced intervals, and wherein at
least some of said energy absorbing means are located in spaces in
said assembly defined between said compartments.
7. In an assembly for use in absorbing energy when the assembly or
structure associated with the assembly is subjected to impact, the
improvement comprising a plurality of flexible chambers positioned
for receiving effects of said impact, a substantially
non-compressible fluid normally located within said chambers,
passage means extending from said chambers, fluid receiving means
connected to said passage means whereby said chambers and said
fluid receiving means are maintained in communication by said
passage means, means for normally retaining at least a major
portion of said fluid in said chambers in preference to said fluid
receiving means, the force of an impact operating to transfer fluid
through said passage means into said fluid receiving means, and
whereby the fluid transferred is moved back to said chambers when
said force is removed.
8. An assembly in accordance with claim 7 wherein the assembly is
associated with a structure comprising protective apparel, and
including sizing means associated with the structure.
9. An assembly in accordance with claim 6 wherein said fluid
receiving means comprises opposed walls normally located in closely
spaced relationship whereby a relatively small space is defined
between said walls, transfer of fluid into said fluid receiving
means operating to increase the size of said space by forcing said
walls apart, said walls being formed of resilient material whereby
the walls are restored to a closely spaced relationship when said
force is removed.
Description
The invention relates primarily to improved helmet constructions
although application to other types of protective equipment is
contemplated. The construction particularly comprises a mechanism
adapted to be employed for receiving impact forces and for
dissipating the forces to thereby materially reduce the adverse
affects of the impact. In addition, the construction includes a
sizing means which permits adaptation of the same helmet to a
variety of individuals and which cooperates in an ideal fashion
with the energy absorbing means.
A wide variety of helmet structures have been designed for
absorbing energy since there are many circumstances where
individuals are susceptible to impact forces which could result in
serious head injuries. In certain instances, the forces arise when
the head strikes a more or less stationary object such as a wall or
an automobile dashboards. In other instances, the forces arise due
to impact which results when another object moves into contact with
the individual. This may occur in contact sports such as football,
or the impact forces could result when workmen are struck by
falling objects.
In addition to energy absorbing means, a proper fit is also of
critical importance in helmet constructions. Provision is made for
fitting by providing a head cradle, usually composed of a plurality
of straps, along with some means for adjusting the straps. This is,
however, somewhat unsatisfactory since completely accurate
adjustments are difficult to make, and since the adjustments can
not be made while the helmet is on the head.
Since an improper fit can result in serious injury, it has been
necessary for helmet manufacturers to make available a complete
range of sizes of helmets. This leads to additional costs both from
the standpoint of manufacturing and due to the fact that users of
the helmets must secure large inventories in order to accommodate
different individuals and to permit immediate replacement.
It is a general object of this invention to provide a novel design
for a construction used for protection against impact forces.
It is a more particular object of this invention to provide a
construction which involves the use of liquids or other
substantially non-compressible fluids for the purpose of
dissipating energy which results from impact forces.
It is a still further object of this invention to provide
constructions of the type described which are adapted to be readily
associated with helmets whereby individuals can be protected
against the adverse affects of impact in a highly effective
manner.
It is a still further object of this invention to provide an
improved sizing means for helmets whereby accurate fitting of a
helmet can be accomplished and whereby the need for a large
inventory of different helmet sizes can be minimized or
eliminated.
These and other objects of this invention will appear hereinafter
and for purposes of illustration, but not of limitation, specific
embodiments of this invention are shown in the accompanying
drawings in which:
FIG. 1 is a vertical, sectional view of a helmet construction
provided with energy absorbing and sizing means characterized by
the features of this invention;
FIG. 2 is a vertical, sectional view of the helmet construction
taken about the line 2--2 of FIG. 1;
FIG. 3 is an enlarged fragmentary, sectional view of an energy
absorbing element utilized in the construction;
FIG. 4 is a vertical sectional view taken about the line 4--4 of
FIG. 1;
FIG. 5 is a plan view of an inflating means which can be used with
the construction of the invention;
FIG. 6 is a bottom plan view of the helmet construction;
FIG. 7 is a schematic illustration of the construction as it is
placed on a person's head;
FIG. 8 is a plan view of a sizing means assembly for location at
the crown and sides of the helmet;
FIG. 9 is a plan view of an assembly of energy absorbing and sizing
means for location in the front of the helmet;
FIG. 10 is a plan view of an assembly of energy absorbing and
sizing means for location at the back and neck areas of the
helmet;
FIG. 11 is an enlarged cross-sectional view, taken about the line
11--11 of FIG. 8, illustrating the valve means utilized in the
construction;
FIG. 12 is an enlarged fragmentary, sectional view illustrating a
snap-in stud construction utilized for securing the energy
absorbing and sizing means in the construction;
FIG. 13 is a perspective view of an alternative design of sizing
means;
FIG. 14 is an enlarged fragmentary, sectional view illustrating an
alternative form of valve mounting means;
FIG. 15 is an enlarged fragmentary sectional view illustrating an
alternative form of fastener means for securing energy absorbing
and sizing assemblies;
FIG. 16 is an enlarged fragmentary sectional view illustrating an
additional type of sizing means;
FIG. 17 is a cross-sectional view illustrating an alternative form
of energy absorbing means;
FIG. 18 is a detailed, fragmentary, cross-sectional view
illustrating the operation of the construction of FIG. 17;
FIG. 19 is a cross-sectional view illustrating schematically the
energy absorbing capabilities of the construction; and,
FIG. 20 is a diagrammatic illustration of an additional type of
energy absorbing means.
The helmet construction of this invention includes means adapted to
absorb energy upon being subjected to impact. The invention
provides for the use of first and second chambers which are
flexible in nature in the sense that the interiors of the chambers
are adapted to increase and reduce in size in response to the
application and removal of impact forces.
A passage means is provided for interconnecting the respective
chambers, and a substantially non-compressible fluid is included in
the first chamber. When an impact force is applied, the fluid is
adapted to be transferred from the first chamber to the second
chamber through the passage means. The work involved in moving the
fluid represents a direct measure of the amount of energy absorbed.
By providing an appropriate design for the energy absorbing means
to fit their location in the helmet, the energy absorption
capabilities will be such that injury or damage can be eliminated
or reduced to a desirable minimum.
The sizing means of this invention generally consist of a plurality
of air compartments situated over the interior surface of the
helmet shell. Valve means accessible from the exterior of the shell
are provided for inflating the compartments whereby the helmet can
be fit while in place on an individual's head. Additional energy
absorbing means are preferably included within the compartments to
provide a back-up in the event of especially high impact or in the
event of failure of the primary energy absorbing means.
In a preferred form of the invention, the combination of the energy
absorbing and sizing means is used together, preferably by placing
these means on a liner which fits within the helmet shell. With
this combination, assembly of the helmet can be accomplished in an
extremely efficient manner. Fastening means for the liner and air
valves are designed to that additional safety features are
provided.
FIGS. 1, 2, 4 and 6 illustrate a helmet 10 provided with the energy
absorbing and sizing means. The energy absorbing means are in the
form of elements 12 including first and second chambers 14 and 16.
The sizing means with associated energy absorbing means include a
first set 18 for engaging the back of the neck, a second set 20
positioned to engage an intermediate area at the back of the head,
a third set 22 extending over the front of the head and a crown and
side set 24.
As shown in FIGS. 8-10, common backing sheets 25 may be provided
for the energy absorbing and sizing means. These backing sheets are
individually attached to the helmet shell which is preferably
formed of a relatively rigid material such as hard plastic, metal,
or the like.
Each of the energy absorbing means carries a non-compressible
fluid, the major portion of which is present in the larger chambers
14. Each chamber 14 communicates with a chamber 16 through
constricted passage 26. Accordingly, when force is applied to the
energy absorbing means, fluid is adapted to be transferred from the
chamber 14 to the chamber 16.
The energy absorbing means 12 are formed of a flexible material
which can be sealed to form fluid-tight chambers, for example by
gluing or heat sealing. Such materials provide the desired
flexibility while also having characteristics which simplify
manufacturing. In the embodiment shown, the energy absorbing means
12 are heat sealed directly to the backing sheet 25. (See FIG. 3).
A heat seal is provided at 28 for purposes of forming the
relatively narrow passage 26 between the chambers (FIGS. 9 and 10).
The size of this passage will determine the amount of force
required to permit transfer of fluid from a first chamber to a
second chamber.
By controlling the extent of heat sealing around the chamber 16,
the size of the chamber can be controlled. This chamber is designed
to normally urge the fluid into the chamber 14. Accordingly, when
an impact force is removed, the energy absorbing elements will
resume their normal configuration. As explained in the
aforementioned copending applications, independent means could be
provided for normally compressing the chamber 16, for example,
resilient bands overlying the chamber 16. It is essential to the
operation of the construction, however, that the fluid be
preferentially included within one chamber for transfer to the
other chamber upon the application of force. Substantially all of
the fluid should, therefore, be in the chamber 14 with only a
minimum amount of fluid, if any, being present in the chamber 16
until a force is applied.
The energy absorbing members 12 are located at strategic points
over the interior wall of the construction. Obviously, the location
of the energy absorbing means should be such that protection will
be provided irrespective of the direction of impact.
The sizing means of this invention each comprise a compartment 32
or a compartment 24' in the case of the crown (FIGS. 8-10). These
compartments are located in spaced apart relationship over the
interior surface of the helmet. The location of the compartments is
selected so that upon inflation of the compartments, the helmet
shell will be evenly spaced apart as much as possible with respect
to the head of the wearer.
The sizing compartments can be manufactured by locating a flexible
material on backing sheet 25 and then sealing off the compartment,
for example, by heat sealing or gluing. In the embodiment
illustrated, the material is heat sealed to the backing sheet
around all edges of each compartment with the exception of small
passages 36 which interconnect the respective compartments. This
arrangement is best illustrated in FIGS. 9 and 10.
A valve 38 may be associated with each compartment or set of
compartments. Referring to the sets 18, 20 and 22 in FIGS. 9 and
10, it will be noted that a valve is associated with the
intermediate compartment, and due to the interconnecting passages
36, all of the compartments 32 can be filled with air
simultaneously. In the case of any set, a single valve can be
employed; however, two or more valves could be positioned at
intervals particularly where greater numbers of compartments are
included in a set.
In FIG. 8, the set 24 consists of a compartment 24' of circular
configuration with a valve 38 communicating with the interior of
this sizing means. This compartment 24' is situated in the crown of
the helmet for engaging the top of the wearer's head. A bellows
type body may alternatively be used for the compartment or for
others of the sizing means.
A second valve means 38 associated with this assembly communicates
with a bubble 41 which, in turn, is connected through the passages
41 to the side compartments 32. As will be explained, these side
compartments are provided with a separate valve so that they can be
inflated separately from the chamber 24' during the fitting
operation.
The backing sheets 25 for each of the configurations shown in FIGS.
8-10 are provided with tabs 43. These tabs define openings 45 for
alignment with corresponding openings in securing bands 47. These
securing bands comprise relatively stiff plastic pieces which are
secured to the helmet wall by means of snap-in studs 49 shown in
FIG. 12. The studs 49 include an enlarged bifurcated end 49' which,
when pressed into reduced diameter openings in the helmet shell,
will hold the bands in a secure position. As best shown in FIG. 1,
the openings in the helmet shell define a counter sunk portion 49"
so that the enlarged end 49' will lock into place.
The sets of energy absorbing and sizing means can be riveted or
otherwise attached to the bands and the bands are then secured to
the helmet shell by means of the snap-in studs 49. The valves 38
are attached to the sizing chamber assemblies prior to attachment
of these assemblies to the bands, and the valves are then adapted
to be snapped into place relative to the helmet shell.
A preferred construction for the valves 38 is shown in FIG. 11. The
valves comprise a beaded inner end 140 whereby a resilient band 142
can be held in place around the valve body. The valve is slit at
144, and a central bore 146 is formed adjacent this slit. Outwardly
extending shoulders 148 are provided so that the valves can be
snapped into openings 150 defined by the helmet shell (FIG. 1).
The slit 144 is provided in the valve for entry of the needle 152
of the inflating means 154 shown in FIG. 5. The inflating device of
FIG. 5 is merely illustrative of a suitable manually held
construction; however, other conventional means can obviously be
employed for this purpose. The inflating means should, however,
include a needle portion which can be inserted in the bore 146 of
the valve and forced through the slit in opposition to the
resilient action of the band 142. The sizing means can then be
inflated in a desired degree while the helmet is on the wearer's
head, and when the needle is pulled out, the band 142 will provide
automatic sealing.
The use of studs 49 and valves 38 is particularly desirable for
athletic helmets. The snap-in characteristics permit secure
attachment of these members without having any protruding portions
so that a smooth exterior can be provided to minimize the
possibility of injuries.
A strip 53 of leather (FIG. 7) may be provided over the
compartments 32 located at the front of the helmet for positioning
against the forehead. This strip of material serves as a sweatband,
and it is preferably adhesively applied to permit easy removal and
replacement.
Although sequence variations are contemplated, particularly where
the design of the individual sets varies, fitting a helmet on the
head of an individual, may commence with the compartment 24' of the
crown area 90 (FIG. 7) being inflated first to provide a
comfortable position of the helmet, for example from the standpoint
of vision. The sets 22 and 20 of compartments 32 in the areas 92
and 94 can then be inflated (preferably in that order) to provide
substantially uniform spacing between the helmet wall and the front
and back of the head. The set 18 is then inflated to engage the
neck properly.
The side compartments 32 of the set 24 are then inflated last to
complete fitting of the helmet, again without disturbing the
position established by the initial inflation. It will be
appreciated that the order of inflation described represents a
convenient and efficient arrangement but that other inflating
sequences are clearly available.
Each of the compartments preferably includes an energy absorbing
element in its interior. These elements comprise a first layer 50
formed of standard resilient material, such as expanded vinyl, used
for the padding of athletic equipment. The other layer 51 is
preferably a crushable material capable of absorbing energy, for
example, expanded polystyrene beads sold under the trademark
Ethafoam.
FIGS. 17 and 18 illustrate an alternative design for the energy
absorbing means 12 comprising a single housing 86 defining a first
chamber 88 and a second chamber 90. The passages 92 and 94
interconnect the respective chambers. A first flap valve 97 permits
fluid in the chamber 88 to pass into the chamber 90 while the flap
valve 98 provides for reverse movement.
A suitable resilient means may be associated with the arrangement
of FIG. 17 for compressing the housing 86 in the area of the
chamber 90 as suggested by the dotted lines. These compressing
means will, therefore, resist entry of fluid in the chamber 90
while operating to urge return of the fluid through the passage
94.
The arrangement shown in FIGS. 17 and 18 differs from the energy
absorbing means 12 primarily because of the ability of the flap
valve 97 to provide for substantial changes in the size of the
passage communicating the first and second chambers. Thus, in the
case of the passage 26, only a relatively small increase in the
diameter of the passage will occur even when high impact takes
place. This increase in diameter occurs because of the resilient
character of the material forming the absorbing means 12.
It will be appreciated that the features of the absorbing means 12
and 86 could be combined whereby a single passage means, having
expansion characteristics, will be provided. For example, the
passage means 100 shown in FIG. 20 comprises a conically shaped
tubular member having a side wall of varying thickness. The opening
101 interconnects the chambers 102 and 104 thereby providing a
normally open passage for movement of fluids back and forth between
the chambers. The material forming the passage is flexible so that
the opening 101, being in the thin wall area, will expand by an
amount depending on the size of the impact force. This is
particularly important in the case of high impact, since otherwise
the resistance of the chamber 102 might approach the resistance of
a solid.
FIG. 19 schematically illustrates the manner in which the various
elements within the construction cooperate. The sizing means 32
absorb the energy resulting from impacts of lower magnitude. In the
case of a football helmet, these sizing means may absorb all the
energy as much as 60 percent of the time.
When greater forces are encountered, the absorbing means 12 come
into play; these absorbing means will probably be used about 30
percent of the time when utilized in football helmets. The
resilient padding 50 can then be used only for the remaining 10
percent of impact forces. As shown in FIG. 19, this resilient
padding may extend closely adjacent the inner surface of the sizing
chamber, in which case, its effect will be utilized for lesser
impact stages. Alternatively, the padding 50 may be of much lesser
extent, and it will then be utilized in later stages of impact. In
any event, even relatively severe impacts encountered during a
football game can be readily accommodated by the three systems
referred to.
The crushable material 51 is provided only for extremely severe
circumstances, circumstances which might be severe enough to cause
bursting of the compartments 32 and absorbing means 12. The
crushable material will give under these severe circumstances and
therefore may not be usable thereafter; however, since other damage
has occurred; sizing means and absorbing means would have to be
replaced in any event.
It will be understood that the energy absorbing means comprising
the units 12 are considered to have utility apart from the sizing
means, and the sizing means likewise have separate utility.
Although the respective means cooperate in an ideal fashion as
described, the utilization of other complementary arrangements with
either of these means is contemplated.
The provision of the sizing means and the energy absorbing means on
a common liner provides many advantages. Assembly is greatly
simplified since accurate placement of the elements on the liner is
easily accomplished. Thus, the assembly can be produced from two
opposing sheets of heat sealable material with the chambers,
compartments, and passages formed in one sheet. Furthermore, the
liner can be easily removed in the event of any defects or failure
of any of the elements on the liner. A replacement liner can be
provided, and there will be no need to discard the helmet shell.
Individual assemblies, for example the set 22, can be used in
combination with other energy absorbing or sizing arrangements
instead of using all the sets together. Finally, the energy
absorbing or sizing means, or an assembly thereof, can be used with
other protective equipment such as shoulder pads, jaw pads, thigh
pads, hip pads, etc.
As shown in FIG. 15, a liner 52 may be provided with strap portions
54 adapted to overlap the peripheral edge of the helmet shell. By
providing openings in these strap portions in alignment with
openings in the helmet shell, the liner can be easily attached and
removed.
One suitable means for securing the liner 52 to the helmet shell
comprises a fastener 56 formed of a tough resilient material. The
fastener includes an enlarged head 58, a reduced diameter shank 60,
and an enlarged end 62. A narrow strip 64 is formed as an extension
of the enlarged end. When the holes in the liner strap and shell
are in alignment, the fastener can be forced through, and then
locked in place when the enlarged end passes the last hole. The
strip 64 can be grasped with the fingers to assist in forcing the
fastener through the holes. By utilizing a resilient material for
the fastener 56, there is a minimum danger of injury if the head
should strike a fastener end.
In the arrangement shown in FIG. 16, a plate 66 is located over the
interior wall of the helmet shell, and an internally threaded
sleeve 68 is passed through an opening in the liner 52 and through
the helmet shell. A screw 70 is then provided for securing the edge
portion 54.
FIG. 14 illustrates an alternative form of valve construction. The
valve comprises a shank portion 72 which extends through an opening
in the helmet shell. The inner end 74 is maintained in spaced apart
relationship with the helmet shell by means of a grommet 76 formed
of resilient material. In the event an impact force is applied in
the area of this valve, it is possible that the wearer's head will
actually be moved so close to the surface of the helmet shell that
there is a danger of the hard valve material injuring the head.
However, before this can occur, the grommet 76 will give thereby
allowing the shank 72 of the valve to move outwardly of the helmet
shell. The helmet constructions of this invention are, of course,
designed so that the wearer's head would never come into contact
with a valve; however, the arrangement of FIG. 14 is considered
desirable as a means for preventing injury in the event of failure
of other components of the helmet or in the event of highly unusual
impact forces.
There has been described an arrangement which provides an extremely
satisfactory means for the absorbing of energy and for properly
fitting a helmet. The use of liquids or any substantially
non-compressible fluid in the energy absorbing means enables the
absorption of energy even at extremely high levels whereby the
detrimental effects of impacts can be reduced to a minimum.
Relatively common liquids may be utilized, for example, an aqueous
solution containing 20 percent CaC1.sub.2. Vinyl sheets are
suitable for forming the energy absorbing and sizing
compartments.
The provision of air or other gas for the sizing means provides a
highly effective and easily handled fitting technique. The
combination of the energy absorbing means and the sizing means is
itself of critical importance particularly since the design of the
respective means lends itself to joint installation, for example,
on a common backing, and since the highly accurate fitting
cooperates with the energy absorbing means in providing a safe
helmet. This latter feature is of major importance since the
provision of an accurate fit, with the sizing means firmly against
the head even where unusual head contours are involved, is very
important in preventing head injury. Thus, if a player has a
prominent knob or other unusual head characteristic, the sizing
compartments will compensate to avoid any looseness.
It will be understood that various changes and modifications may be
made in the above described constructions which provide the
characteristics of this invention without departing from the spirit
thereof particularly as defined in the following claims.
* * * * *