Abstract:
A protective helmet includes an outer layer and an inner layer interconnected by multiple connectors under tension along their longitudinal axis. The connectors absorb energy from an impact force by resisting further tension along their longitudinal axis and allow the outer layer and inner layer to move relative to each other. In protecting the head of a user, the helmet reduces the amount of impact force experienced, reduces the change in momentum or position of the head and neck, reduces head and neck loads and reduces the amount of linear and rotational acceleration. The helmet can be used in numerous applications and environments, including for participants in sports, including football, baseball, lacrosse, racing, skiing, for commercial activities, including construction, and for military personnel, including pilots and soldiers.

Description:
TECHNICAL FIELD OF THE INVENTION 
     The present invention generally relates to protective helmets and more particularly to helmets that can absorb, at least in part, an impact force. 
     BACKGROUND OF THE INVENTION 
     Protective helmets have been worn to protect a user from head injuries. Protective helmets have been used for many endeavors, including for participants in sports (e.g., football, baseball, lacrosse, racing, skiing), for commercial activities (e.g., construction) and for military personnel (e.g., pilots, soldiers). Prior art helmets have generally comprised a single layer which is rigidly secured to the head of a user. 
     U.S. Pat. No. 4,287,613, entitled “Headgear With Energy Absorbing and Sizing Means” disclosed a headgear of the type used by football players. The headgear included a web suspension means comprising looped straps held together by a cord that threads through the looped straps and is knotted. The web suspension means performed a sizing function and maintained the top of the wearer&#39;s head out of contact with the upper wall of the helmet shell. The ends of the straps were connected to an encircling band that was fastened at selected locations to the helmet shell. 
     U.S. Pat. No. 5,035,009, entitled “Protective Helmet and Liner” disclosed a protective helmet having a sheet of sound deadening material between impact force absorbing pad structures disposed on the interior of the protective helmet. 
     Recent advances in helmets include U.S. Pat. No. 6,826,509, entitled “System And Method For Measuring The Linear And Rotational Acceleration Of A Body Part.” The &#39;509 patent discloses a system using accelerometers to collect, record and process head acceleration data. See FIG. 7 of the &#39;509 patent. See also the related U.S. Pat. No. 7,526,389. 
     U.S. Pat. No. 7,954,177 entitled “Sports Helmet” disclosed a sports helmet having ear flaps and jaw flaps. 
     SUMMARY OF THE INVENTION 
     The present invention is a protective helmet for protecting the head of a user. The protective helmet includes an outer layer and an inner layer. The outer layer is connected to the inner layer by multiple connectors that are under tension along their longitudinal axis. The connectors absorb energy from the force of an impact by resisting further tension along their longitudinal axis and allow the outer layer and inner layer to move relative to each other. The helmet affords a reduction in the amount of force from an impact that is transferred to the head of a user. The helmet also affords a reduction in the amount of force transferred from the helmet to another object, such as another helmet. The protective helmet also affords a reduction in the change in momentum or position of the head of a user that would otherwise occur. The protective helmet also affords a reduction in the amount of rotational force transferred to the head of a user that would otherwise occur. The helmet can be used in numerous applications and environments, including for participants in sports (e.g. football, baseball, lacrosse, racing, skiing), for commercial activities (e.g. construction) and for military personnel (e.g. pilots, soldiers). 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a more complete understanding of the invention and for further advantages thereof, reference is now made to the following Description of the Preferred Embodiments taken in conjunction with the accompanying Drawings in which: 
         FIG. 1  is a cross-sectional view of a protective helmet according to the present invention. 
         FIGS. 2A-2B  depicts the relative orientations of the layers of the protective helmet of the present invention before, during and after an impact with an object. 
         FIG. 3  is a cross-sectional view of a protective helmet according to the present invention as used for a football helmet showing the face guard connected to the outer layer and a chin strap connected to the inner layer, this embodiment can afford a reduction in the change in momentum or position of the head of a user that would otherwise occur. 
         FIG. 4  is a cross-sectional view of a protective helmet according to the present invention depicting additional components and features. 
         FIG. 5  is a cross-sectional view of a protective helmet according to the present invention depicting an adjustor to adjust the connectors. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The following detailed description of the preferred embodiments should be read in view of the FIGS. in which the same reference numerals are used to refer to the same or corresponding components of the novel protective helmet of the invention. 
     As shown in  FIG. 1 , the novel protective helmet  100 , includes an outer layer  102 , an inner layer  104  and multiple intermediate connectors  106 . The multiple intermediate connectors  106  connect inner layer  104  to outer layer  102 . Connectors  106  preferably connect outer layer  102  to inner layer  104  such that each connector  106  is under tension along its longitudinal axis. The protective helmet  100  can further include other connectors  106  that are not under such tension. Each of inner layer  104  and outer layer  102  may, in certain embodiments, be referred to individually as a shell. 
     As shown in  FIGS. 2A-2B , the multiple intermediate connectors  106  are deformable so as to allow relative movement between inner layer  104  and outer layer  102 . Protective helmet  100  in a state of rest may exist as shown in  FIG. 2A  prior to encountering a force  108 . 
     As shown in  FIGS. 2A-2B , force  108  is an external force that is less than the amount of force needed to move the head of a user that is in a relatively fixed position. This amount of force may be considered a “low impact” external force. Force  108 , however, could also be an internal force exerted by the head of a user. In the case of a low impact external force  108 , upon the exertion of the external force  108 , the front portion  110  of outer layer  102  is impacted. As a result, the force  108  is transferred to outer layer  102  and deforms at least some of the connectors  106 . The distance between the front portion  110  of outer layer  102  and the front portion  112  of inner layer  104  may be reduced as shown in  FIG. 2B . To absorb the force  108 , the connectors  106  connecting the rear portion  114  of inner layer  104  and the rear portion  116  of outer layer  102  are stretched generally along their longitudinal axis. By resisting further tension along their longitudinal axis, these connectors  106  serve to absorb the force  108 . In addition, the connectors  106  connecting the front portion  110  and the front portion  112  may be compressed. Thus, the connectors  106  absorb forces and/or resist deformation. Preferably, connectors  106  are also elastic in that, after an impact, they seek to regain their shape and/or orientation to their original position prior to the exertion of a force  108 . Preferably, this reversal occurs quickly. After an impact, inner layer  104  and outer layer  102  return to their original relative orientation as shown in  FIG. 2A . 
     In one preferred embodiment, all of the connectors  106  are under tension such that they are further stretched as a result of an impact occurring on the opposite side of the helmet  100 . The connectors  106  therefore do not serve to absorb forces through compression along their longitudinal axis; rather, they resist further tension or stretching generally along their longitudinal axis. Thus, connectors  106  absorb energy from an impact force  108  by resisting further tension along their longitudinal axis, generally on the opposite side of the protective helmet  100  than the side of impact. Thus, the connectors  106  allow the outer layer  102  and the inner layer  104  to move relative to each other so as to reduce the amount of force from an impact that is transferred to the head of a user and/or the amount of force from the head of a user that is transferred to the environment surrounding protective helmet  100 . 
     An “equal” force  108  is an amount of force needed to equal the resistance-to-change in the position of the head of a user in a fixed position or to counter the momentum of the head of a user in motion. A “high impact” force  108  is an amount of force needed to change the position of the head of a user in a fixed position or to exceed the momentum of the head of a user in motion. 
     Protective helmet  100  reduces the amount of movement of the head and neck of a user that would otherwise occur. Protective helmet  100  can reduce the amount of a force  108  that is transferred to the head and neck of a user. Protective helmet  100  can afford a reduction in the amount of force transferred from the helmet to another object, such as another helmet. The multiple connectors  106  absorb energy from an impact with force  108  caused by another object and allow outer layer  102  to move relative to inner layer  104  so as to reduce the amount of force from said impact that is transferred to the head and neck of a user. In addition, the movement of outer layer  102  relative to inner layer  104  reduces the amount of movement, including rotational movement, of the head and neck of a user that would otherwise occur from an impact. Likewise, the force of the head of a user in motion that is transferred to another object is reduced by the relative movement of inner layer  104  to outer layer  102 . 
     The afforded reduction in the transfer of force is beneficial in reducing head and neck injuries. In addition, the afforded reduction in relative movement and/or the change in momentum of the head of the user is beneficial in reducing head and neck injuries. The reduction of the amount of change in position and/or of momentum of the head of the user afforded by the present novel protective helmet  100  is a significant advantage over prior art helmets. If the head of the user is at rest relative to its surrounding environment, it is considered to have no momentum. Thus, an impact with an object exerting force  108  may change the position of the head of the user. If the head of the user is in motion relative to its surrounding environment (e.g. a football field), then it has momentum. Thus, an impact with an object exerting force  108  may change the momentum of the head of a user. Protective helmet  100  affords a reduction in the amount of change in position of the head of a user at rest that would otherwise occur as a result of an impact with an object exerting a force  108 . Protective helmet  100  affords a reduction in the amount of a change in momentum that the head of a user in motion would otherwise experience as a result of an impact with an object exerting a force  108 . 
     In the event that the outer layer  102  is in a fixed position, such as possibly for a race car driver, protective helmet  100  would still afford a reduction in the amount of force and or change in momentum that would occur in the absence of protective helmet  100  in view of the movement of inner layer  104  relative to outer layer  102  and the response of connectors  106  to a force  108 , whether it be a force external to protective helmet  100  or an internal force caused by the head of a user or a combination thereof. 
     Force  108  is not part of the novel protective helmet  100 . Force  108  could be any object, such as another helmet; or in a commercial environment could be a falling object; or in the case of a military environment could be a bullet or other projectile. 
     Outer layer  102  may absorb some of the impact of a force  108 . Connectors  106  may absorb some of the impact of a force  108 . Inner layer  104  may absorb some of the impact of a force  108 . Preferably, the impact energy of force  108  is absorbed by the protective helmet  100  so that no amount of the force is transferred to the head of a user. A “reduction” in force includes reducing it to zero. 
     Connectors  106  can be any material that absorbs forces, such as rubber or springs. Connectors may be of different lengths and thicknesses. Connectors  106  can vary along their length as to the type of material and/or the amount of retention force or force absorption. Connectors  106  can have different cross-sectional shapes, e.g., circular. The cross-section of the connectors  106  can also vary along the length of the connector  106 . Connectors  106  can be of different lengths. Connectors  106  can be forked or pronged at one or both ends. Connectors  106  can be intertwined. Connectors  106  can be tubular. Connectors  106  can be of different angles of attachment, including different angles at each connecting end relative to the inner layer  104  and to the outer layer  102 . For example, connectors  106  can be connected perpendicular to the surface of outer layer  102  or inner layer  104  or can connect to such layers at an angle. Such angles could be measured relative to a tangent line intersecting the point of a connector  106  at which it is connected to either outer layer  102  or inner layer  104 . 
     In one embodiment, connectors  106  are cylindrical. Connectors  106  can be of solid material or hollow (e.g., the same material used in resistance tubes). Connectors  106  can also be configured to be replaceable. Hollow connectors can include internal connectors  106  that can in turn be solid or hollow. In one embodiment, the inner connector can be under a different amount of tension than the outer surrounding connector. For example: an inner connector can be under less or no tension but can have a higher resistance to deformation; whereas, the outer connector can be under greater tension, but can afford a lesser amount of resistance to deformation; or vice versa. 
     Connectors  106  can also serve different functions, including the use of some connectors  106  to offset the force of gravity on outer surface  102  so as to maintain the optimum relative orientations between outer layer  102  and inner layer  104 . Connectors  106  can also be subdivided into sets of connectors, each set having its own function, shape, orientation and or type of material. In one embodiment, there are three sets of connectors, a first set serving to absorb low impact forces, a second set serving to absorb essentially equal forces and a third set serving to absorb high impact forces. In one embodiment, connectors  106  are disposed in lines parallel to the expected angle of impact on opposite sides of protective helmet  100 , preferably along the same line as the angle of approach of force  108 . 
     Connectors  106  can serve to reduce the amount of multiple forces  108 , including an external force  108  that impacts outer layer  102  and an internal force  108  caused by the head of a user. In this case, the amount of the external force  108  that is transferred to the head of a user is reduced and the amount of impact force  108  of the head of a user with protective helmet  100  is reduced. In addition to reducing the amount of transferred forces of impact, protective helmet  100  can reduce the amount and/or the speed of relative change in position of the head of a user of protective helmet  100 . 
     Protective helmet  100  serves also to reduce the amount of rotational force exerted by a force  108 . Rotational forces can cause head and neck injuries. Thus, the reduction in the amount of rotational force transferred to the head of a user as a result of protective helmet  100  is a significant advantage over prior art helmets. 
     Upon impact of an impact force  108  with the outer layer  102  of protective helmet  100 , connectors  106  can exert a force on inner layer  104  along the same line of impact but on the opposite side of the impact. The afforded displacement of impact allows for the reduction in the amount of force  108  transferred to the head of a user and/or allows for a reduction in the change of momentum of the head of a user. The afforded displacement of impact also allows for a decrease in the amount of acceleration or deceleration that the head of a user would otherwise experience. 
     In one preferred embodiment, the connectors  106  are arranged so as to afford the maximum reduction in the force of impact from any given angle. In this embodiment, the connectors  106  substantially surround the head of a user. In other words, to the extent that the inner layer  104  can be referenced as somewhat spherical, the connectors  106  would be connected to inner layer  104  along preferably greater than at least 180 degrees based upon any plane cross section taken through the center of the sphere defined by the inner layer  104 . Preferably, connectors  106  are displaced in at least one complete hemisphere of the general sphere of the head of a user. Such sphere being divided into two equal hemispheres by any plane passing through its center. 
     In one preferred embodiment, the connectors  106  are disposed generally symmetrically. For example, the connectors  106  are generally symmetric along a plane of symmetry crossing through the center of the sphere generally formed by the protective helmet  100 . In one preferred embodiment, this plane of symmetry is vertical and passes from the front portion  110  of the outer layer  102  through the center of the sphere to the rear portion  116  of the outer layer  102  of protective helmet  100 . 
     Preferably, connectors  106  are the only connections between inner layer  104  and outer layer  102 . In the event that there are other members connecting inner layer  104  to outer layer  102 , such additional members are preferably configured so as to not reduce the energy absorption otherwise afforded by connectors  106 . 
     As shown in  FIG. 2A , when the force  108  exerted as shown in  FIG. 2B  is removed, the outer layer  102  and the inner layer  104  return to their orientation as shown in  FIG. 2A . Likewise, connectors  106  preferably return to their original length and orientation. The connectors  106  preferably allow for repeated cycles of force absorption and recovery. 
     Preferably, the outer layer  102  is designed so as to ensure that all external forces impact outer layer  102  prior to engaging inner layer  104 . 
     Preferably, connectors  106  are connected directly between inner layer  104  and outer layer  102 . In certain embodiments, it is preferred that the angle of contact of the connectors to the inner layer  104  and outer layer  102  be approximately 90 degrees. 
     Preferably for environments involving heat, outer layer  102  can include multiple openings  118  to allow air circulation, as shown in  FIG. 4 . Likewise, inner layer  104  can include multiple openings  120 . 
     As shown in  FIG. 3 , protective helmet  100 , when used in certain application (e.g., as a football helmet), can include a face guard  122  and/or a chin strap  124 . Face guard  122  is preferably secured to outer layer  102 . Chin strap  124  is preferably connected to inner layer  104 . In this embodiment, the head of a user is fixed relative to the inner layer  104  not only by means of the shape of the inner layer  104  but also by use of the chin strap  124 . The outer layer  102  and the optional face guard  122  are allowed to move relative to inner layer  104 , including as a result of an impact from a force  108  and/or an internal force caused by the head of a user. 
     Face guard  122  can be a clear, transparent material. Face guard  122  can afford a reduction in the amount of light (e.g., serve as a sun visor). Face guard  122  can be formed of a unitary, solid material or may include one or more openings or bars. 
     Contrary to the present invention, prior art football helmets undesirably use a chin strap connected to the outermost rigid layer that fixes the position of the head of the user to the relative position of the outermost rigid layer. One advantage of this embodiment of the present invention is afforded by the ability to connect a chin strap  124  to inner layer  104  to allow for movement of inner layer  104  relative to outer layer  102 . In this embodiment, protective helmet  100  can be secured to the head of a user, but the outer layer  102  is not directly secured to the head of a user and thus can move relative to inner layer  104  in response to an impact force  108 . 
     Outer layer  102  can be formed of a single shell of rigid or flexible material or can have multiple layers or zones of the same or different material. Outer layer  102  can be made of clear, transparent material. 
     Outer layer  102  can be made of a high force resistance material, including materials used in protective vests, including layers of very strong fiber (e.g., Kevlar) used to slow and deform a projectile, such as a bullet. The ability to deform a projectile affords the ability to spread its impact force over a larger portion of the outer layer  102 . Protective helmet  100  can absorb the energy from the deformed projectile, bringing it to a complete stop or at least reducing its speed before it can completely penetrate the outer layer  102 . The connectors  106  can reduce or eliminate the amount of force transferred to the head of a user. Inner layer  104  can also be made of such high force resistance material. 
     Inner layer  104  can be formed of a single shell of rigid or flexible material or can have multiple layers or zones of the same or different material. Inner layer  104  can include a rigid outer surface secured to the connectors  106  and a soft inner surface conforming to the head of a user. The inner surface of inner layer  104  may also include additional sizing layers, members or elements so as, to afford a customized fit for a given user. 
     As shown in  FIG. 4 , outer layer  102  can include a padding member  126  on an inner surface  128 . Padding member  126  can be in the form of a layer, matrix of material or a multitude of individual members. 
     As shown in  FIG. 4 , inner layer  104  can include a padding member  130  on an outer surface  132 . Padding member  130  can be in the form of a layer, matrix of material or a multitude of individual members. 
     The distances between outer surface  132  of inner layer  104  and inner surface of outer layer  102  can be the same for the entire protective helmet  100 . These distances can also be different for different regions of the helmet, including but not limited to, the front portions, rear portions, top portion and side portions. 
     The distances between the outer layer  102  and  104  and or the connectors  106 , (including number, size, shape, location, amount of tension and type of material) can be altered for specific applications. For example, for construction environments, it may be preferable to have a greater distance between the outer layer  102  and inner layer  104  at the top region of protective helmet  100 , which such distance is greater than would otherwise be desirable for other applications; and further to have stronger connectors  106  along the sides of the protective helmet  100 . Moreover, even within a general application, such for football helmets, the distances between the outer layer  102  and  104  and or the connectors  106  (including number, size, shape, location, amount of tension and type of material) can be altered for specific players or positions. 
     Padding members  126  and  130  can both be included. Padding members  126  and  130  can be oriented to contact to each other at a state of rest and/or to contact each other only under some impact force. Padding members  126  and  130  can be oriented to not contact at a state of rest and/or to not contact even under some impact force. 
     Preferably for certain environments, the inner layer  104  and the outer layer  102  are designed so as to afford an airflow to reduce what would otherwise be an undesirably high internal temperature of the protective helmet  100 . Protective helmet  100  can include a cooling member  134 , as shown in  FIG. 4 . 
     Preferably for certain environments, the inner layer  104  and the outer layer  102  are designed so as to afford a higher temperature than would otherwise be an undesirably low internal temperature of the protective helmet  100 . Protective helmet  100  can include a heating member  136 . 
     Preferably, protective helmet  100  can include a communication device  138 . Communication device  108  can include one directional, bi-directional or multi-directional communications, including voice and visual communication. Communication device  138  could afford communication between a user of protective helmet  100  to any other person, such as another player, a coach or a commander. 
     Communication device  138  can be connected to a display  140 . Display  140  can display any information or image, whether stored or communicated in real time. 
     The materials used for protective helmet  100  may differ depending upon the specific application. For example, protective helmet  100  as used for firefighters may require the use of more heat resistant materials that may in turn be heavier and or more costly than would be desirable for other applications. 
     In certain applications, the protective helmet  100  can include one or more motion sensors or accelerometers  142 . Preferably, motion sensor  142  is connected to protective helmet  100  to detect movement occurring to or relative to the rear portions and or to the sides of protective helmet  100 . Motion sensor  142  can be connected to display  140  and or communication device  138 . 
     In certain applications, the protective helmet  100  can include a camera  144 . Camera  144  can be connected to display  140  and or communication device  138 . One or more cameras  144  can be mounted on protective helmet  100 . Camera  144  can display a rear view to a user via display  140 . 
     As shown in  FIG. 5 , protective helmet  100  can include one or more adjustors  146 . Adjustor  146  allows for the increase and/or decrease in the amount of tension of one or more connectors  106 . Adjustor  146  may also allow for a change in position of one or more connectors  106 . Adjustor  146  can be formed of a threaded portion  152  having a channel  154  and a moveable portion  156 . Moveable portion  156  can be adjusted so as to move a connector  106  through channel  154 . Preferably, adjustor  146  is flush with the outer surface of outer layer  102 . 
     Motion sensor  142  can be used to detect the speed, size, orientation and/or direction of impact of an incoming force  108 . This information can be communicated to communication device  138  and/or to display  140 . A light, signal or communication can be generated in advance, during and or after an impact so as to indicate an impending, ongoing or recent impact. Such a communication can also indicate whether an undesirable threshold has been exceeded so as to remove a player and/or to inspect protective helmet  100 . Preferably, this information can be communicated to one or more adjustors  146  that can adjust connectors  106  in accordance with the information so as to maximize the amount of protection afforded by protective helmet  100 . This dynamic impact response system has many useful applications, including in military applications. This dynamic impact response system can be installed within protective helmet  100  and can be monitored and/or controlled locally or remotely by a local or remote computer. In addition, the impact information can be stored. The impact information can include the movement of connectors  106 , outer layer  102  and inner layer  104 . By assessing the information gathered, an angle of approach of force  108  may be determined. This angle is useful in detecting the location and source of the force  108 , e.g., for determining the location of a sniper. 
     Protective helmet  100  may also include sensors that monitor the acceleration and/or change in momentum and can communicate same to the dynamic impact response system. In this embodiment, protective helmet  100  responds in real time to an incoming impact force  108  by using sensors that communicate to connectors  106 . A power source, preferably one or more batteries, can be used and secured to protective helmet  100  and operably connected to the various preferred components disclosed herein through one or more electrical circuits as understood by one of skill in the art. 
     As shown in  FIG. 5 , protective helmet  100  may include a right side portion  148  and a left side portion  150 . Right side portion  148  can be disposed over the right side of the head of a user. Left side portion  150  can be disposed over the left side of the head of a user. For certain applications, for example, where protective helmet  100  is used as a batting helmet for baseball, only one of the side portions  148  and  150  may be included. The inner layer  104  may include one or more openings  158  around the ear of the user. 
     In one embodiment, outer layer  102  can envelope most of the head of the user, including the top, sides, front and back of the head of a user; and inner layer  104  can envelope most of the head of the user, including the top, sides, front and back of the head of a user. The portion of inner layer  104  that extends over the face of a user can include multiple connectors  106  to improve the performance of the protective helmet  100  from rear impacts. In this embodiment, the front portions of both the outer layer  102  and the inner layer  104  are transparent. In another embodiment, one or more of the layers envelope less than most of the head of the user. 
     Those of skill in the art understand that various changes and modifications can be made to these preferred embodiments without departing from the invention disclosed and claimed herein. All such changes and modifications are intended to be covered by the following claims: