The disclosure provides headgear systems. More particularly, the disclosure provides headgear systems having an air-bubble cushioning liner to improve shock absorption performance.
Traumatic brain injury (TBI) is a major cause of death and disability in the United States. According to the Centers for Disease Control, the number of TBI-related emergency department visits, hospitalizations, and deaths increased by 53% over the past ten years. For example, in 2014, an average of 155 people in the United States died each day from injuries that include a TBI. Those who survive a TBI can face effects that last a few days, or possibly the rest of their lives. Effects of TBI can include, but are not limited to, impairments related to thinking or memory, movement, sensation (e.g., vision or hearing), or emotional functioning (e.g., personality changes, depression). These issues affect not only individuals but also families and communities, and can have lasting negative effects.
Approximately 7.3% of traumatic brain injury cases identified by the Ontario Trauma Registry were work-related. Many epidemiological studies suggest that the work-related traumatic brain injury (WrTBI) is thought to be one of the most serious occupational injuries that occurs among construction workers. WrTBIs may result in extensive medical care, multiple days away from work, permanent disability, or death.
The industrial helmet is accepted as the most common and effective personal protective equipment to reduce the WrTBIs. Industrial or construction helmets are categorized as either Type I or Type II, according to international standards. The Type I construction helmet is the most commonly adopted helmet model used on construction sites. A Type I helmet is designed for top impact protection only, and does not provide protection for lateral impacts. A representative Type I helmet typically includes a hard shell, which is typically molded using polyethylene or polycarbonate plastics, and a strap suspension system. The strap suspension system usually plays a major role in shock absorption and impact force redistribution. The suspension system in a basic Type I helmet may usually include a synthetic woven webbing and bands of molded nylon or vinyl. In an advanced high-performance Type I helmet, there may be an additional polymer shock absorption liner between the belt suspension and shell. Since the suspension system may play a role in absorbing impact shocks in a helmet, the research and development efforts of such helmets has been primarily focused on the improvement of the strap suspension system. The suspension system of construction helmets may have different designs and may use different shock absorbing materials.
There exists a need for industrial or construction headgear system, such as helmets, with improved shock absorption performance to improve the headgear design, thereby improving workers' safety.
The present disclosure provides headgear protection systems for preventing or reducing work-related traumatic brain injury and/or risk. More particularly, the disclosure provides headgear systems having an air-bubble cushioning liner to improve shock absorption performance.
In one aspect, the disclosure provides a protective headgear assembly that includes: a protective body having an inner surface and an outer surface; a shock suspension system affixed to the inner surface of the protective body having an upper surface and a lower surface, wherein the upper surface is proximate to the inner surface of the protective body; an air-bubble cushioning liner; and a strap affixed to the shock suspension system.
In some embodiments, the air-bubble cushioning layer is affixed to the lower surface of the shock suspension system.
In some embodiments, the air-bubble cushioning layer is affixed to and coextensive with the lower surface of the shock suspension system.
In some embodiments, the air-bubble cushioning layer is substantially coextensive with the lower surface of the shock suspension system.
In some embodiments, the air-bubble cushioning layer comprises one or more layers of air-bubble wrap.
In some embodiments, the air-bubble cushioning layer comprises an upper layer of air-bubble wrap and a lower layer of air-bubble wrap oriented so that a bubble-side of the upper layer faces a bubble-side of the lower layer.
In some embodiments, the first layer is adhered to the second layer.
In some embodiments, the air-bubble cushioning liner has a thickness of 5 mm.
In some embodiments, the one or more layers of air-bubble wrap have a thickness selected from the group consisting of ⅛ inch, 3/16 inch, 5/16 inch, and ½ inch.
In some embodiments, the protective body is a helmet.
In some embodiments, the helmet is a Type 1 industrial helmet model.
In some embodiments, the air-bubble cushioning layer is affixed to the inner surface of the shock suspension system with an adhesive.
In some embodiments, the adhesive is Dycem 50-1560Y.
In some embodiments, the upper layer is adhered to the lower surface of the shock suspension system and the lower layer is proximate to a user's head.
In some embodiments, the air-bubble cushioning liner is made from a material selected from the group consisting of low-density polyethylene (LDPE) film, high-density polyethylene (HDPE) film, polypropylene (PP) film, and combinations thereof.
In some embodiments, the air-bubble cushioning liner is dome-shaped and an upper dome surface is adhered to the inner surface of the shock suspension system.
In some embodiments, the air-bubble cushioning liner is sized to fit a user's head.
In an aspect, the disclosure provides a method of making a protective headgear assembly, including the steps of: providing a protective body having an inner surface and an outer surface; affixing a shock suspension system to the inner surface of the protective body, the shock suspension system having an upper surface and a lower surface; and adhering an air-cushioning liner onto the lower surface of the suspension system.
In some embodiments, the air-cushioning liner comprises an upper layer of air-bubble wrap and a lower layer of air-bubble wrap oriented so that a bubble-side of the upper layer faces a bubble-side of the lower layer.
The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate various example methods, and other example embodiments of various aspects of the invention. It will be appreciated that the illustrated element boundaries (e.g., boxes, groups of boxes, or other shapes) in the figures represent one example of the boundaries. One of ordinary skill in the art will appreciate that in some examples one element may be designed as multiple elements or that multiple elements may be designed as one element. Furthermore, elements may not be drawn to scale.
Approximately 7.3% of traumatic brain injury cases identified by the Ontario Trauma Registry were 24 work-related (Kim et al., (2016) Int J Environ Res Public Health 13:11). A study of an Abu Dhabi (United Arab Emirates) hospital records between 2005 and 2009 indicated that 56 (about 10%) of a total of 581 TBI cases were related to occupational activities (Salem et al., Traumatic brain injuries from work accidents: a retrospective study, Occup. Med. (Lond.) 63 (5) (2013) 358-360.). Another study of hospital records in northern Italy from 1996 to 2000 showed that approximately 15% of TBI incidents occurred in workplaces (Baldo et al., Epidemiological aspect of traumatic brain injury in northeast Italy, Eur. J. Epidemiol. 18 (11) (2003) 1059-1063.). A surveyance of the insurance records in Taiwan for 2009 showed that 11% of occupational injuries requiring hospitalization involved TBI (Lin et al., Psychological outcome of injured workers at 3 months after occupational injury requiring hospitalization in Taiwan, J. Occup. Health 54 (4) (2012) 289-298.). Construction is the leading industry for serious work-related traumatic brain injuries (WrTBI) due to the high incidence of falls and head struck-by incidents (Hino, Y., Fundamental study on relationship between human injury probability due to fall and the fall height, Work 41 (Suppl 1) (2012) 3339-3342; Liu et al., Work-related mild-moderate traumatic brain injury and the construction industry, Work 39 (3) (2011) 283-290; Lombardi et al., Work-related falls from ladders—a follow-back study of US emergency department cases, Scand. J. Work Environ. Health 37 (2011) 525-532.). Many epidemiological studies suggest that WrTBIs are one of the most serious occupational injuries among construction workers, resulting in extensive medical care, multiple days away from work, and permanent disability, or death (Hino et al., 2012; Liu et al., 2011; Lombardi et al. 2011; Thurman et al., Traumatic brain injury in the United States: A public health perspective, J. Head Trauma Rehabil. 14 (6) (1999) 602-615; Tiesman et al., The epidemiology of fatal occupational traumatic brain injury in the U.S, Am. J. Prev. Med. 41 (1) (2011) 61-67; Konda et al., Fatal traumatic brain injuries in the construction industry, 2003-2010, Am. J. Ind. Med. 59 (3) (2016) 212-220.). Approximately 15.6% of WrTBI incidents resulted from struck-by objects on the head (Liu et al. 2011; Kim et al., Traumatic brain injury occurring at work, Neuro Rehabil. 21 (4) (2006) 269-278; Coleman, V., Occupational head injury accidents in Great Britain, J. Occup. Acid. 8 (1986) 161-172.). It is generally accepted that the industrial helmet is the most used and effective personal protective equipment available to reduce WrTBI (Kim et al. 2016; Tiesman et al. 2011). OSHA (Occupational Safety and Health Administration) regulations require workers to wear a helmet to reduce risk of head injury from falling objects (OSHA, 1926.100/1910.135: Safety and Health Regulations for Construction, Personal Protective and Life Saving Equipment. Occupational Safety and Health Administration, Washington, D.C.).
Industrial helmets (also referred to as construction helmets) are categorized as Type I or Type II according to the ANSI Z89.1 standard. A Type I helmet is designed for top impact protection only, whereas a Type II helmet is also designed for protection from lateral impacts. Industrial helmets widely used in construction and manufacturing industries are mostly categorized as Type I. All Type I helmets have to pass the top impact test (i.e., Type I impact test), in which an impactor drops freely from a certain height or at a certain impact velocity onto a fixed helmet; the maximal peak transmitted impact force shall be smaller than a certain limit for the helmet to pass the test. There are three most frequently used international test standards for industrial helmets: ANSI Z89.1 (ANSI, ANSI/ISEA Z89.1: American National Standard for Industrial Head Protection, American National Standards Institute, Washington, D.C.), EN397 (BS, EN 397:2012+A1: Industrial Safety Helmets, British Standards Institution, London, UK), and EN14052 (BS, EN 14052: 2012+A1: High Performance Industrial Helmets, British Standards Institution, London, UK). The ANSI Z89.1 standard is mainly used in North America, whereas EN397:2012+A1 and EN14052:2012+A1 are European standards. In ANSI Z89.1 standard, the impactor has a mass of 3.6 kg, freely drops, and impacts the helmet's crown at a velocity of 5.5 m/s. To pass the test, the maximal transmitted force must be less than 4.45 kN. The impact test required by European standard EN397 specifies an impactor (mass 5.0 kg) that freely drops from a height of 1.0 m and impacts onto the helmet; the maximal acceptable peak transmitted force is 5.0 kN. European standard EN14052 is for high-performance industrial helmets. It requires the helmet to be tested not only with top and lateral impacts, but also with off-crown impacts, in which the impactor strikes onto the helmet at angles of 15°, 30°, 45°, and 60°.
Prior art Type I helmets consist of a hard shell and a suspension system. The helmet shell is typically molded using polyethylene or polycarbonate plastics. According to ANSI Z89.1, the use of chin strap is optional in Type I helmets. The suspension system plays a major role in shock absorption and impact force redistribution. Although the suspension systems of Type I industrial helmets produced by different manufacturers utilized different materials, their structural designs are similar. The suspension system in a typical Type I helmet consists of a synthetic woven fabric strips and bands of molded nylon or vinyl. The suspension molded bands are attached to the shell via a 4-point or a 6-point ratchet. In addition to a strip-type suspension, Type II helmets have a pad liner, mostly made of foam materials. There is an advanced high-performance helmet (Kask safety helmet; KASK Inc, Chiuduno, Italy) on the market, which has an additional polymer shock absorption pad liner between the strip-type suspension and shell. High performance industrial helmets will pass EN14052 tests, which are more stringent than the Type I and Type II tests in ANSI Z89.1. Since the suspension system plays an essential role in absorbing impact shocks in a helmet, the research and development efforts of helmets have mainly been focused on the improvement of the suspension system (Corrales et al., Validation of a football helmet finite element model and quantification of impact energy distribution, Ann. Biomed. Eng. 48 (2019) 121-132. Decker et al., Development and multi-scale validation of a finite element football helmet model, Ann. Biomed. Eng. 48 (2020) 258-270.). Prior art industrial helmet designs have not considered implementing air-bubble cushions because these types of cushions are generally used for protection in scenarios that involve relatively small impacts, which are not consistent with the needs of an industrial helmet.
Compared to other conventional shock absorption materials, such as rubbers and polymers, air-bubble cushions have the advantages of being light weight, low cost, and unique mechanical performance attributes. Air-bubble cushions have been widely used in scenarios where humans interact with the equipment or environment, for example, shoes, shock-absorption gloves, seat cushions, and air bed mattresses. Air cushioned soles have been used in shoes to improve shock absorption performance and comfort for decades (Falsetti et al., Hematological variations after endurance running with hard- and soft-soled running shoes, Phys. Sportsmed. 11 (8) (1983) 118-127.). In air-cushioned gloves, finger segments are cushioned by separated air-bubbles to absorb the vibrations transmitted to the hand (Hewitt et al., Anti-vibration gloves? Ann. Occup. Hyg. 59 (2) (2015) 127-141.). The vibration absorption performances of air-cushioned gloves were found to be dependent on the vibration frequencies and grip forces (Welcome et al., Tool-specific performance of vibration-reducing gloves for attenuating fingers-transmitted vibration, Occup. Ergon. 13 (1) (2016) 23-44.). The dependence of the contact stiffness of an air-cushioned glove on the air pressure and bubble sheet materials have been analyzed theoretically (Wu et al., An analysis of contact stiffness between a finger and an object when wearing an air-cushioned glove: the effects of the air pressure, Med. Eng. Phys. 34 (3) (2012) 386-393.). Air-bubble buffers have been used in hip protectors to protect the elderly from hip fractures (Song et al., Study on buffer characteristics of air cushion used as hip protector, J. Appl. Biomater. Funct. Mater. 16 (1 Suppl) (2018) 32-36; Boroujeni, S., Inflatable Hip Protectors, M. Sc. Thesis, Simon Fraser University, Vancouver, B.C., Canada, 2012.). Air cushion seats have been applied to improve the interface contact pressure distributions on the human body (Lee et al., Effects of different seat cushions on interface pressure distribution: a pilot study, J. Phys. Ther. Sci. 28 (1) (2016) 227-230.). Air-bubble cushions have been used in football helmets to provide an additional layer of padding while increasing comfort and the fit of the helmet (L. Schwartz 2011 Types of Padding in Football Helmets, SportRec). In all these scenarios, the air-bubble cushions have been used to reduce contact stress or to absorb small impact force in the contact interface between the human and equipment.
Air-bubble cushions have also been widely used in the packaging industry (W. Soroka, Fundamentals of Packaging Technology, IoPP, Naperville, Ill., USA, 2002.). An air-bubble wrap sheet—a common packing material in industries—consists of two low-density polyethylene (LDPE) films, with one bubble-shaped film being bonded to a flat film to form air-bubbles. The pressure of the initial inflation air may be varied in accordance with the sheet material properties and requirements of the package contents to be protected. Air-bubble wrapping sheets are commercially available in different thicknesses, bubble sizes, and bubble densities. For example, the air-bubble size can be as small as 3/16″ (6 mm), to as large as 1″ (25 mm) in diameter. The most commonly used air-bubble wrapping sheet has an air-bubble diameter of 10 mm (K. Yam, Encyclopedia of Packaging Technology, John Wiley and Sons, USA, 2009.). Compared to other packing materials, air-bubble wrapping sheet has the advantages of excellent shock absorption characteristics, light weight, insensitive to climate conditions (e.g., temperature and humidity), and high flexibility (Yam 2009). Malasri et al. (Plastic tote distribution, Int. J. Adv. Packag. Technol. 1 (1) (2013) 40-52.) showed that the impact acceleration in the contents packed with 3/16″ (5 mm) and 5/16″ (8 mm) bubble wrapping is about 34% less than that packed with viscoelastic foam wrapping. Despite widespread adoption of air-bubble cushions in ergonomic designs and in commercial packaging as shock absorption materials, they have never been used in industrial helmets. Moreover, no prior art applications have assessed whether air-bubble cushions would also be effective in absorbing large impact forces, such as those observed with the industrial helmets.
The present disclosure is based, at least in part, on the discovery that air-bubble cushions are able to effectively absorb and dissipate large impact forces such as those encountered in industrial work environments, and that inserting one or more layers of air-bubble cushioning in between a user's head and the shock suspension system of a helmet (e.g., a construction helmet) dramatically improves the impact absorption/dissipation characteristics of the helmet. The helmets disclosed herein can be used to improve the shock absorption performance of Type I industrial helmets. Advantageously, the helmets disclosed herein have markedly improved impact absorption/dissipation abilities relative to prior art Type I industrial helmets. Additionally, the helmets disclosed herein are lightweight and inexpensive to manufacture. Furthermore, the present disclosure provides an additional modular layer of protection (e.g., an air-bubble cushioning liner) that can be retrofitted onto presently available industrial helmets. A further advantage of the present disclosure is that inserting one or more layers of air-bubble cushioning in between a user's head and the shock suspension system of a helmet dramatically increases the endurance of a helmet under multiple impacts, thereby significantly increasing the safety of the helmet users, and increasing the lifespan of the helmet.
The experimental set-ups 110 and 120 (see e.g.,
Before data collection from the experimental set-ups depicted in
ΔE=mgh−½mv2 (1)
where m (3.6 kg) and g (9.8 m/s2) are the impactor mass and gravitational acceleration, respectively. The relative energy loss, δ, is estimated by compare ΔE to the potential energy:
The raw time-history data of the transmitted force and acceleration were processed using a MATLAB program to find the maximal peaks. The relationships of the peak transmitted forces and peak acceleration to the drop height 104 were analyzed. In order to evaluate the contribution of the air-bubble cushioning liner 124 to the helmet shock absorption performance, an impact force reduction coefficient is defined:
where Fmax, no-air and Fmax, air are the mean peak forces for Group I test (unmodified helmets) and Group II test (helmets with added air-bubble cushioning liner), respectively.
If the data collected from the Group I test are independent of those collected from the Group II test, the standard deviation of the impact force reduction coefficient, Sη, is estimated by the Taylor approximation. K. M. Wolter, Taylor Series Methods, Introduction to Variance Estimation, Springer, New York, 1985:
where smax, no-air and Smax, air are the standard deviations of the Group I test and Group II test, respectively.
Table 2 presents the mean peak transmitted forces (F max in kN) for Group I (unmodified Type 1 helmets 112) and Group II (unmodified Type 1 helmets 122) for different impact numbers and different drop heights 104. The values shown are means of four replication tests. The impact tests were stopped once the measured peak force values reached 20 kN. The highlighted force values are higher than the force limit of 4.45 kN, which is the maximum allowable value to pass the ANSI consensus standard ANSI Z89.1. The data presented in Table 2 are illustrated in the exemplary graphs of
ANSI consensus standard ANSI Z89.1 standard requires a top impact dropping with an impactor of 3.6 kg at a velocity of 5.5 m/s, which is approximately equivalent to a drop height of 1.73 m at perfect the data gathered in
It was also observed that the helmets 112, 122 show a narrow scattering (low standard deviation value) in the peak transmitted force data when the shock absorption performance is in the stable range (i.e., h<1.73 m) (
Overall it was deduced that adding an air-bubble cushioning liner 124 to the unmodified Type 1 helmet 112 may substantially increase shock absorption performance for large impacts. The current data gathered in
References to “one embodiment”, “an embodiment”, “one example”, and “an example” indicate that the embodiment(s) or example(s) so described may include a particular feature, structure, characteristic, property, element, or limitation, but that not every embodiment or example necessarily includes that particular feature, structure, characteristic, property, element or limitation. Furthermore, repeated use of the phrase “in one embodiment” does not necessarily refer to the same embodiment, though it may.
To the extent that the term “includes” or “including” is employed in the detailed description or the claims, it is intended to be inclusive in a manner similar to the term “comprising” as that term is interpreted when employed as a transitional word in a claim.
Throughout this specification and the claims that follow, unless the context requires otherwise, the words ‘comprise’ and ‘include’ and variations such as ‘comprising’ and ‘including’ will be understood to be terms of inclusion and not exclusion. For example, when such terms are used to refer to a stated integer or group of integers, such terms do not imply the exclusion of any other integer or group of integers.
To the extent that the term “or” is employed in the detailed description or claims (e.g., A or B) it is intended to mean “A or B or both”. When the applicants intend to indicate “only A or B but not both” then the term “only A or B but not both” will be employed. Thus, use of the term “or” herein is the inclusive, and not the exclusive use. See, Bryan A. Garner, A Dictionary of Modern Legal Usage 724 (2d. Ed. 1995).
Ranges can be expressed herein as from “about” one particular value and/or to “about” another particular value. When such a range is expressed, another aspect includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent “about,” it is understood that the particular value forms another aspect. It is further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint. It is also understood that there are a number of values disclosed herein, and that each value is also herein disclosed as “about” that particular value in addition to the value itself. It is also understood that throughout the application, data are provided in a number of different formats and that this data represent endpoints and starting points and ranges for any combination of the data points. For example, if a particular data point “10” and a particular data point “15” are disclosed, it is understood that greater than, greater than or equal to, less than, less than or equal to, and equal to 10 and 15 are considered disclosed as well as between 10 and 15. It is also understood that each unit between two particular units are also disclosed. For example, if 10 and 15 are disclosed, then 11, 12, 13, and 14 are also disclosed. In this regard, ranges provided herein are understood to be shorthand for all of the values within the range. For example, a range of 1 to 50 is understood to include any number, combination of numbers, or sub-range from the group consisting 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, or 50 as well as all intervening decimal values between the aforementioned integers such as, for example, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, and 1.9. With respect to sub-ranges, “nested sub-ranges” that extend from either end point of the range are specifically contemplated. For example, a nested sub-range of an exemplary range of 1 to 50 may comprise 1 to 10, 1 to 20, 1 to 30, and 1 to 40 in one direction, or 50 to 40, 50 to 30, 50 to 20, and 50 to 10 in the other direction.
While example systems, methods, and other embodiments have been illustrated by describing examples, and while the examples have been described in considerable detail, it is not the intention of the applicants to restrict or in any way limit the scope of the appended claims to such detail. It is, of course, not possible to describe every conceivable combination of components or methodologies for purposes of describing the systems, methods, and other embodiments described herein. Therefore, the invention is not limited to the specific details, the representative apparatus, and illustrative examples shown and described. Thus, this application is intended to embrace alterations, modifications, and variations that fall within the scope of the appended claims.
This application claims the benefit of U.S. Provisional Application No. 62/966,456, filed Jan. 27, 2020; the entire contents of which are hereby incorporated by this reference.
Number | Date | Country | |
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62966456 | Jan 2020 | US |