CA2180184A1 - Laminated material to protect against soft x-rays - Google Patents

Abstract

The present invention relates to a laminate material for use as protection against the soft x-ray component of electromagnetic radiation particularly in arc welding.
The preferred laminate material comprises an outer layer of flame resistant material, an intermediate layer of radiation shielding material selected from the group consisting of one or more layers of aluminum foil, aluminum sheeting or a fibrous mat or weave of aluminum wire and an inner layer of flame resistant material.

Description

TITLE: T,AMTNATF: MATERIAL FOR PROTECTION
AGAINST SOFT X-RAYS

Field of the Invention This invention relates to occupational health and safety, and in particular to a laminate for the protection of personnel from the chronic and acute health hazards of Soft X-rays. It also relates to the protection of hearing within a welding helmet, and to the protection of personnel from extreme heat.

Description of the Prior Art Hitherto, it has been preferred for welding wear fabric to consist of heavy leather g I ~:. covering inner garments of some flame resistant fabric (FRF) such as cotton. However, this protection is limited to arc light from the ultraviolet region.

~Iowever, in the arc welding environment an electric current flows from metal surface to another in order to generate the heat required for fusion. The physica~ act

2 1 8~ 1 84 of striking a metal surface with a flow of electrons liberates electrons from the outer shell of the metal creating a form of radiation called Soft X-rays. Soft X-rays are a form of radiation between ultraviolet and X-ray radiation which have greater ability to penetrate matter than ultraviolet but less energy than X-rays. Soft X-rays can be defined as having wavelengths greater than 0.1 Any ,~- but less that 10 An~:,Lr ~ - . The essential characteristic of Soft X-rays is they have a wavelength which is comparable to the distance between electron shells and atomic nuclei.

In the arc welding environment, electric current flows to force electrons against an exposed metal surface. The result is a scattering of both electrons and photons in the immediate vicinity. Electrons flowing outside a contained electric current are frequently called beta particles. Since both electrons and photons are neither particle nor wave, and' each is in itself a logical cull~LL~ ion ~ iqn~d for man to understand the microscopic world in a macroscopic context, the term Soft X-ray radiation will be used to delineate all forms of energy, particulate and wave; electron, beta particle and with a wavelength between 0.1 An~, - and 10 Ang~ ~L ~ - .

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3- 21~0~84 Mathematically, Soft X-ray radiation should be produced by a lOO volt arc. The gain in kinetic energy as the electron accelerates equals the loss of potential energy. 2 1/2mv = eV

v= 2eV/m = (2) (1.6xlO**-19C) (lOOV)/(9.lxlO**-31)kg v= 5 . 9x10**6 m/s 6.6 xlO J.s =h/mv =

(9.1 x 10 kg) (5.9xlOm/s) = 1.2 x lO m These equations show that an electron accelerated across an arc with a voltage of lOOv does so with wavelengths that can approach 1. 2 An~LL in length, which is well within the Soft x-ray region of the ele. LL gnDtiC
ff~e~;~L ~I~U. While these equations describe the electrons within the arc and not the reflected beta particles or the emitted photons, the equ;~tions d l_Lc~te a substantial risk of occupational hazard from the welding arc to both personnel health and weld quality as it relates to manual dexterity during the welding process.

However, despite widespread concern of some unknown health hazard in the arc welding environment,review of the popular literature regarding welding processes has found no consideration of Soft ~-ray radiation and a 21~3184 review of U.S. Patent 5,210,878, u.S. Patent 4,117,554, U.S. Patent 4,445,232, U.S. Patent 5,222,257, U.S.
Patent 5,323,815 and U.S. Patent 5,172,426 has found no measures taken to effectively shield against Soft X-ray radiation .

Arc welding consists of numerous different processes which utilize different ~ h1nDs. Flux Core Arc Welding ( FCAW), Tungsten Inert Gas (TIG) welding Metal Inert Gas (MIG) welding pose a greater risk than Stick Metal Arc welding(SMAW). Welding in the vertical up position poses a greater t:XpO~>ULe: to the chest than other positions. Radiation risk is also determined by voltage and <l~e of the current source. ~igh voltage currents will create radiations of smaller wavelengths while raising amperages will increase the amount of radiation without altering the nature of the radiation.
It is also possible th~t other electrical devices and other ele~;LI gnDtic envi~ L~ expose people to Soft X-rays. Potential hazards include computer monitors, televisions and other cathode ~ay tubes, electric lighting and radio transmission equipment.

The medical effects of Soft X-rays are largely undetDrmi necl, While the medical practice of chemotherapy 21 ~18~
~ --s--has provided a wealth of knowledge regarding the effect of X-ray radiation upon biological tissue, the study of the effect of Soft X-rays upon biological tissue is less advanced. Also, welding personnel suffer from symptoms of premature aging which mimic non-lethal and chronic doses of radiation injury such as chronic hair loss, rP~ldPnin~ of the skin, increased thickness of the horny layer of the skin and lung cancer. The similarity of many of these symptoms to that of smoke inhalation may have caused mi~rl;i~gno5i5. Soft X-rays pose a potential health hazard in the welding environment.

If we assume that Soft X-ray radiation has biological effects comparable to X-ray radiation then the areas of the body most vulnerable to Soft X-rays would be those which divide rapidly such a~i the skin, blood forming organs, lungs, gonads and in~estines. Radiation injury is not limited to the killing of radiosensitive cells however. The initial injury leads to secon~ry di~uLl,an~ es and reparative processes, often through systemic - -ni Fm~ which modify the primary injury.
Radiation injury often simulates other injuries and is neither unique or specific.

Soft X-ray radiation may reduce the quality of manual 21 ~01 ~4 welding. While large amounts of gamma radiation are required to kill adult nerve cells, transitory neurological effects can result from relatively small doses. An intensive exposure to the brain of 50 Gy, or 50 joules / kilogram, of gamma radiation will i n, S?ra~itate the nervous system and can lead to death in minutes. It is possible then that Soft X-ray radiation in the welding environment could lead to transitory neurological dist~lrh~n~Ps which reduce weld quality without leading to identif iable acute or chronic health hazards. Reduced weld quality leads to increased product cost, product failure, environmental spills need for extensive testing.

The Process of manual arc welding exposes certain areas of the body more than others due to- their closer proximity to the welding arc ~ The hand, head and chest area typically receive the greatest exposure to Soft X-rays. The chest and throat area are perhaps the most highly risked area since they are both exposed and vulnerable. Also, people below'the age of thirty are increasingly vulnerable.

One means of avoiding arc light radiation is the use of oxyfuel welding processes which combine oxygen with a C 7 218~184 fuel to create a high flame temperature. Since the only radiation created is black~ody radiation, radiation emitted from hot objects to the surrounding ai ~-re, r~o Soft X-ray radiation is emitted. However, tr~ - ldoll-heat in the form of infrared radiation limits the usefulness of the technique due to discomfort of personnel and distortion of work. E~--r i~- limitations have limited the use of oxyfuel welding to small runs of thin sheet.

Complete protection against any form of matter penetrating radiation is i - - - i hle. It is only possible to form a shield which removes a higher percentage of the radiation. Matter can interfere with radiation by reflection, absorption and diffraction. Any radiation not affected by these three pL~,cesses travels through the matter and is said to be~transmitted. once it has been estimated what th~ n~c5 rémoves 509s of the radiation, this thi~-kn~cc can be multiplied until the radiation emitted is reduced to a reasonable level. A
secondary material of difreren~ composition is often incorporated to alter the nature of the emitted radiation .

All elements transmit narrow bands of ele~;LL ~ tic -C~ ~ 21801~4 radiation which are detr-nminPd the element's atomic structure. The wavelengths of these are detPrmi nr-~ by the electrons in the elements electron shells, with a band created by each electron. The i nnF~ electron shell, the K-shell, has two electrons which create an emission band each. These two ~m1c~jrn bands are called K-line emissions. The electrons of the second shell, called the L shell, create L-line emissions. M-line and N-line emissions also exist. K-line ~ qi ~nc are the most intense and are from five to ten times greater than L-line emissions. While these emission spectra are generally considered to consist of photon tr~n-~i cci ~n only, it is not known by the inventor at the time of this application whether electrons are transmitted through matter according to similaF emission spectra.

When the element is heated to a sufficient tr - c.Lu~, the elements radiate pLotons at these same narrow bands in a process called hl i~l~khody radiation. The t-mL ~I.u~ ~s involved in arc welding generate enough heat to generate bl~ckhody rad;ation in the ultraviolet region but not in the Soft X-ray region.

Hitherto, welding personnel have had intense and sometimes injurious quantities of heat applied to 218~184 their hands. u.S. patent 4,445,232 protects against heat through the use of PVC foam, however, the use of fibrous refractory material may yield greater heat protection with less loss of flexibility. Fibers of alumina mats have been made without the addition of binders. These mats are made of alumina, otherwise known as aluminum oxide and are highly effective as heat shields and thermal barriers since the surface area of these fibers is between 100 and 150 square meters per gram. These fibrous mats of alumina are soft and flexible, having a silky texture. Aluminum oxide provides no unique protection against radiation in the Soft X-ray region.

r Hitherto, hearing protection has not been designed to provide variable protection. Instead, conventional protection of the ear canal has been designed to be on or of f, so that the in'sulation that protects during long periods of machine operation, etc. must be removed, clumsily adjusted or overcome through the raising of the voice during periods of co~versation. The use of the conventional welding helmets also renders conventional hearing protection muffs inap~ iate since they do not fit within the helmet. Plugs fit within the helmet but raise the risk of ear ~nfectlon.

-lo 2 1 8~1 8~
Prior attempts to protect people from soft X-ray radiation have relied upon thick pieces of stationary and heavy material such as concrete block or lead plate. No known attempt has been made to produce garments whihc shield from soft X-rays. Leather garments have been used with the stated purpose of shielding from ultraviolet radiation.

Prior attempts to protect hearing have relied upon ear muffs, which can not fit within a welding helmet, or ear plugs, which can raise the risk of ear infection. None of the prior hearing protection is designed to be variable .

Prior attempts to insulate personnel from heat have been bulky and cumbersome for garments which require a high degree of mobility and manual dexterity from the wearer.

SUMMARY OF THE INVENTION

It is an object of this invention to provide a laminate which gives i _.,v~d protection to personnel from the chronic and acute effects of Soft X-rays within arc light radiation in the welding environment, yet wh~ch is --~t _ ~ 2~8~1~4 light enough in weight and flexible enough to be worn.

It is an objective of this invention to provide garments which will provide protection against Soft x-rays.

It is also an obj ect of this invention to provide a method of variable hearing protection which can be worn comfortably within a conventional welding helmet.

It is also an object of this invention to create a laminate to provide greater insulation against heat in a manner which can be comfortably worn.

It is an object of this invention to provide.for the attenuation of soft x-rays while permitting the passage of visible light.

r It is an object of this invention to protect the ears from the chafing effect of Velcro pads.

Accordingly, the present inven~ion providQs f or a laminate material for use as protection against the soft xray: , l. of ele~ nt~1 ir. radiation. ~he laminate material comprises an outer layer of preferably flame resistant material, an int~ -';Ate layer of ~ 21 ~0184 radiation shielding material and an inner layer of preferably flame resistant material. While all matter provides some protection against radiation, including Soft X-rays, aluminum is generally the most efficient due to its high density of reactive electrons. Aluminum is so reactive on the microscopic scale that when in a solid it forms a thin oxide layer on its external surface to render the obj ect essentially inert on the macroscopic scale. Yet the reactive electrons in the interior of the metal are still able to interfere with radiation. This rh~nl -n~n makes particular sense when we consider radiation from beta particles, which are essentially electrons travelling freely without a nucleus. Because electrons repel each other; we would expect the abundance of freely charged electrons within aluminum solids to exert more stopping power than other matter. As shown above, the arc welding environment is theoretically known to~ generate beta particles with wavelengths in the pe~ L-ting Soft X-ray of the ele. ~L~ _ tic ~e~;~Lulu. It is not yet clear that any photons from the Soft X-ray region are directly generated by the arc welding process since blackbody radiation will be confined to the ultraviolet region and above. Photons may be indirectly created when electrons collide, although they will have wavelengths greater 2 ~ 4 ~ -B-than that of the beta particles. However, any photons generated by the arc welding environment also receive increased interference from the higher electron density of aluminum via the Compton effect or the photoelectric effect. Aluminum is manufactured foils, sheets and wires all of which can provide interference of Soft X-ray radiation.

Like all elements aluminum has a characteristic emission spectrum in the Soft X-ray region of the ele. ~L -tic spectrum. Aluminum transmits radiation at 8 . 3392 A, 8.3367 A, 7.981 A and 169.8 A. The first three bands are at the higher wavelength region of the Soft X-ray spectrum while the last lies within the ultraviolet region. The wavelengths of the emission bands tend to decrease into the more dangerously penetrating regions of the Soft x-ray spectrum as the atomic number of the element increases. Absprption of the emission bands can be effectively attained by the use of cloth and leather, because they are essentially made from the element carbon which has a single ~ inn band at 44 A.
Absorption of these bands is provided by the inner layer of the laminate. In the particular case of the welding environment, these emission bands will also be absorbed by coveralls and street clothes which are worn beneath ~ -T4- 21 8~1 ~4 protective welding wear.

This invention has been developed and tested by the inventor and found to give subjective evaluations of increased weld quality with reduced symptoms acute radiation injury. Such acute symptoms include lack of concentration, eye strain, s ~ Ar tremors during welding, irritability, fatigue and ;nfl: tion of the throat. Elowever, further field testing will raise ethical dilemma.

This invention provides lightweight protection from soft x-rays in garment form through the incorporation of a laminate with a central metallic aluminum la~yer. The high electron density of aluminum gives it extraordinary ability to interfere with soft x-rays, particularly when the radiaition is in the form of beta particles.

This invention provides for the simultaneous transmission of visible light and the protection from soft x-rays by using a thick la,yer of material which is transparent to visible light.

This invention provides for protection of hearing by L-:ssing deformable foam rubber ear muffs again~t 2180~84 ~ --~5--the head by a prosthetic device which adjusts around the neck in collar form.

This invention provides for the insulation from extreme heat using a laminate with a central layer of heat shielding and th~rr-l ly insulating refractory fibers held between two lay~rs of impe ious fabric r 2~0~84 DESCRIPTION OF THE DRAWINGS

Referring to the drawings, Figure l shows a perspective drawing of the laminated material with the bottom left hand corner ~ mi n;lted for convenient viewing.

Figure 2 shows a section view of the laminated material.

Figure 3 shows a plain view of the head and shoulders of the user while wearing the cap and neck cover, the veil and W protecting safety goggles.

Figure 4 shows a plain view of the user from head to toe while wearing the cap and neck cover, W protecting safety goggles, the chest pad, the armlets, the gloves, coveralls and work boots.

Figure 5 shows a plain view of the user from head to toe while wearing the ~ of Figure 4 plus the welding mask with acrylic viso~; plus the ~ront and back apron.

Figure 6 shows a plain view of Figure 5 ~rom the side view.

-17- 2180t84 .
Figure 7 shows a plain view of the front apron.

Figure 8 shows a plain view of the back apron.

Figure 9 shows a plain view of the chest pad.

Figure 10 shows a plain view of the users head while wearing the cap and neck cover with hearing protection muffs in place.

Figure 11 shows a plain view of the user' s head while wearing hearing protection taken from the side view.

Figure 12 shows a plain view of the pattern for the cap portion of the cap and neck cover.

Figure 13 shows a plairl view of the neck cover.

Figure 14 shows a plain view of the back of the glove.

Figure 15 shows a plain view of the front of the glove.

Figure 16 shows a plain view of the armlet for the dominant arm.

-1~ 21~0~84 .
Figure 17 shows a plain view of the veil.

Figure 18 shows a plain view of the welding helmet with acrylic visor and dark lens but no he;~lh~nrl assembly taken from the side view.

Figure 19 shows a plain view of the hearing protection muff .

Figure 20 shows a plain view of the hearing protection muff taken from the side.

Figure 21 shows a plain view of the hearing protection muff as it is, ~ ssed against the ear by the force of the collar flap.

Figure 22 shows a plaip view of the relat;~n~h;r between the ear and the hearing protection muf f when the chin is thrust f orward .

Figure 23 shows a plain view of the relationship between the ear and the hearing protection muf f when the head is in the normal posture position.

-lg- 2 1 8~ 1 84 Figure 24 is a perspective of the acrylic visor inside of the welding mask while the laminate of the welding mask has been cut away to expose the laminate structure.

Figure 25 is a perspective of the ear chafing protector with the upper right hand corner folded to reveal the Velcro pad on the reverse side.

Figure 26 is a section view taken from Figure 15 showing the laminate construction of portions of the glove, namely the back of the hand and the front of the wrist .

DESCRIPTION OF THE ~ ;~su EMBODIMENT

The laminate of the present invention as shown in Figure 1 and Figure 2 is primarily comprised of three layers.
The exact composition ,of the laminate will very from garment to garment. The outer layer 2 will vary between heavy leather, 3.5 oz per square foot, and/or fire resistant fabric(FRF). Weight and economy are the factors detPl~n;n;n~ the outer layer for each garment.
The outer layer shields against sparks and flames while diffracting radiation reflected ~rom the inner metal layer. The leather and the FRF may be joined by a ~lexible adhesive such as poly vinyl acetate(PVA) 5. The inner radiation shielding metal layer 1 will vary ~ler~n~in~ upon the extent of the radiation hazard, the allowable weight det~rmi n~ by the distance of the ~abric from the body's centre of gravity and the fleYibility requirements of the laminate. Possible forms of the metal are metal sheets, foils and fibrous mats.
The metals will be adhered to each other and to fabric or leather by both an adhesive such as contact cement 6, and by stitching. The adhesive must be non-flammable when dry. The inner layer 3 will be made of flame resistant fabric (FRF~ such as denim cotton. When leather and metal thickness are not prohibitive, the three layers will also be joined by unbreakable thread such as upholstery thread 4 . The edges o~ heavy sheet and mat may be bordered by heavy stitching to keep them in place .

The inner radiation chi~ldinq layer will preferably be made from aluminum. While all matter provides some radiation chi-~lrlinq, aluminum iS the preferred metal of choice for general protection due to its high electron density. Aluminum is so reactive on the microscopic scale that as a pure, metal solid it is practically inert on the macroscopic scale. ~etallic aluminum 2 1 ~01 84 --2:
reacts very quickly with oxygen 50 that a layer of oxide protects atoms on the interior of the metal from chemical reaction while allowing them to retain their unbound electrons. When radiation penetrates the aluminum in the form of beta particles, photons or waves, these unbound electrons are able to have stopping power above that of the bound electrons in other metals.
Aluminum also has a low number on the periodic table which gives it a high number of electrons when compared to its atomic weight. The availability and ductility of aluminum also make it the best choice for general protection against Soft X-ray radiation. It is possible that the K-line and L-line discontinuities of aluminum at approximately 8 and 170 An~ L : may coincide with spectral peaks in the emission curves of arc light environments or other ele~iLL tic environments.
While ele.;~L.Iuc.y.letic enviro~ments with such emission curves are unknown at this time, their discovery may necessitate the use of alternative metals, a flexible f ibrous carbon material or very heavy leather either to supplement or replace aluminum. Alternate metals are not advised since their K-line emission spectra lie in the higher energy low wavelength frequencies.

Figure 3, Figure 4, Figure 5 and Figure 6 show app~rel 2~8~8~
made from the laminate material o~ Figures 1 and 2 to be worn by welders. The chest pad 9, the armlets 12 and the gloves 11 are worn over the coveralls 23 which are worn over street clothes and over the work boots 21.
Spats may also be worn to cover the work boots, although these are not shown. The cap and neck cover 10 is worn over the head and it attaches to the veil 13. Safety goggles 19 are worn . Elearing muf f protectors 16 and ear chafing protectors 17 are both available for use at the user's discretion. The front apron 7 and the back apron 8 are worn over the chest pad. The welding mask 14, complete with acrylic visor 15 and dark lens 20 attach to the ho~lhs~nr7 assembly 18 to make the welding helmet which is worn over the head while it is wearing the cap and neck cover 10 and the safety goggles 19.

The front apron of Figure 7 is designed to provide general light weight protection against the injurious effects of Soft X-rays. It is comprised of 5 layers of aluminum foil 1 held between two layers of f ire resistant fabric(FRF) 2, 3 by çontact cement 6 and stitching 4. It covers from the ~ho~ or blades to the lower thigh. Lightweight aluminum sheet 26, approximately 28 gauge, supplements the metal foil layer 1 in the region of the front apron which covers from the ~ 2lsals4 bottom of the ribcage to the upper thigh area. This of fers increased protection to the intestinal and gonad region without restricting body movement. The qho~ Dr straps 27 on the front apron is wide to displace the weight to the shoulders in a comfortable manner. A pair of snaps 23 is placed at the rear of the qho~ Dr strap.
These allow the wearer to raise the level of the apron to cover some of the neck, while allowing the shoulder strap to create a hole large enough for the head to pass through when putting the garment on. If a snap becomes detached accidentally, the apron will continue to hang in front of the body. As shown in Figure 8 A back apron with five layers of aluminum foil 1 protects the back of the body from radiation which is scattered b~ welding booth walls. The back apron is essentially similar to the front apron except for tailoring of the qhmll dDr strap and the omission of increased intestinal protection. The back apron attaches to the front apron by four snaps 22, 28 placed along the front on the chmll ~Drs. The back apron is readily removable for use in hot environments. Snaps arç preferable to buttons or studs since they do not permit the passage of sparks or allow small holes through which radiation can pass.
They are also not prone to frayed edges. Side straps 25 attach through grommets 24 in the side of both front and ~ 21~01~4 back aprons to keep the aprons close to the body.

The chest pad as shown in Figure g drapes over the shoulders. The front piece 33, which holds the protective breastplate 29, attaches to the back piece 34 in the dorsal regions of the chest cavity using snaps 30. The front piece is stitched to the back piece along the shoulders. The outer layer 2 is heavy leather and FRF to provide the radiation and f ire protection of the prior art. A metal breastplate an eighth of an inch thick covers the rib cage to protect this exposed and vulnerable area from Soft X-rays. The chest pad extends below the ribcage with a covering of heavy leather 2 and five layers of aluminum foil l to protect the intestinal and gonad regions without impairing comfort or ease of movement. Personnel with lower back problems may consider some sort of girdlin~g belt to provide prosthetic 6upport of llhe heavy breastplate 29. The breastplate is held in place upon the chest pad by an appropriately sized cloth of denim 3 and upholstery thread 4 . Snaps at the deltoid ,and pectoral region 31 of the ~ho~ r joint receive the armlet snaps as l/2" wide velcro strips encircle the chest pad's two armlet openings 3 2 .

21 ~01 ~4 The cap 35 and neck cover 36 laminate in Figure lo, Figure 11, Figure 12 and Figure 13 is designed for flexibility. The radiation shielding metal layer 1 is comprised of f ive layers of aluminum foil . This protection is PnhAncPd on the inner collar flap by a plainly woven mat of one eighth inch diameter aluminum wire 42. The neckcover snaps together at the front by three snaps 3 9, 4 o to prevent spark entrance and ensure radiation protection. The ear area of the neck cover is covered by a four inch by four inch Velcro square 41 to support the ear protection detailed in drawing 10. The degree of ear protection provided is primarily set hy a Velcro strap 43 on the collar of the neck cover. The neck cover covers to the temple region to prevent the blocking of peripheral vision. The male half of snaps 52 are placed at the temple of the cap to accept the female portion of the veil snap 52 while avoiding the hPA~7hAn~
of the welding helmet.~ The cap portion utilizes 35 a pattern similar to that of a standard welding cap. An elasticized band 44 sown to the inner surface of the cap portion ensures that the cap will cling snugly to the head of the welding personnel.

As detailed in Figure 14 and Figure 15 the laminate for the gloves is cut in a pattern similar to standard -welding gloves. The radiation shielding metal layer 1 is comprised of a plainly woven mat of aluminum wire a 6ixteenth of an inch in diameter and is confined to the back of the hand 45 and the front section of the wrist ~6 only, since these are the portions of the hand which are exposed to radiation during welding and since maximum flexibility is required for the inside of the palm and fingers. To protect against the intense heat flux which the back of the hand 45 and front of the wrist receive, a heat shielding laminate is attached to these areas as shown in Figure 26. The flexibility and heat shielding abilities of the aluminum oxide fi~er 69 are utilized by containing the fibers within two layers of 1. 0 oz per square foot glove leather 70 . ~he two layers of leather are held close to each other by stitching with upholstery thread to ~ ~ss the naturally fluffy aluminum oxide fibers. To prevent the escape of irritating aluminum oxide fibers, each layer of 1. 0 oz . leather is adhered to another layer of 1. 0 oz. glove leather by a flexible adhesive such as PVA and the laminate is sewn to the inner surface of the inner layer 3.The inner surface of the fingers and of the palm consist of heavy leather only, 3.5 oz per square foot, to maintain the flexibility of the prior art.

_~7~ 3 0 ~ ~ 4 As detailed in Figure 16, the layer of metal foil in the armlets consists of approximately ten layers aluminum foil . This heavy foil provides a stif fness which permits movement of the joint while providing a r7;7mrPninq action to reduce fine q~~-71 ;7r tremors and spasms which ~7Ccn-~ny and deteriorate delicate welding procedures.
This metal foil layer is reduced to one layer of foil in the elbow region 50 of the dominant arm. The dominant arm is the right arm for right handers and the left arm for left handers. This reduction in the foil 7-hinknF,cc increases flexibility in this ergonomically critical elbow area. The armlets are attached to the chest pads by a ring of velcro straps 49 and snaps 47,48 at the deltoid and pectoral portions of the shoulder joint. A Velcro strip ensures a close fit of the sleeve to prevent spark entrance.

,.
The veil, as shown in ~igure 17, attaches to the cap portion by a snap at each temple region 52. The outer and inner layer of ~abric as well as the radiation shielding metal layer are all thin for comfort and flexibility. The veil's purpose is to protect against small amounts of radiation which penetrate or scatter behind the denser protection of the mask. The veil drops below eye level to permit vision while extending ~ 21801~4 below the chin to protect the face. It is rec~ -nSad that the veil not be used when the visor region of the helmet is cold to prevent condensation of the breath upon the visor.

The welding mask, as shown in Figure 18, is similar in the shape of its design to conventional welding helmets with a h~ Ahl?n-l assembly hole 53 which is identical in size and position to the welding helmets of the prior art. This will permit the utilization of accessory hardware from the helmets of the prior art such as the hf~;-rlh;~n~ assembly 18 and the dark lens assembly 20. It utilizes a standard dark lens with clear covering lenses and it requires W protecting safety goggles :to be worn n~ rnaath. The mask however is made from an eighth of an inch die cast aluminum 67 covered on both sides by fiberglass 66, 68. This protects against soft X-rays and against dangerous reflections of W from polished aluminum surfaces. The inside of the helmet is painted black to absorb stray light. The visor region of the helmet is protected from soft X-rays by a one inch thick piece of clear acrylic plastic 54. This acrylic lens is held in place behind the helmet by a acrylic filter holder which is shown in Figure 24. It is similar to that of the other lenses for ease of cleaning and 2~ ~0 ~ ~4 .. ~ ~
replacement but is adhered to the new mask by either adhesive or screws.

The ear pieces, as shown in Figure 19 and Figure 20 are each comprised of two quarter inch thick pieces of foam rubber 57, 58 surrounded by two layers of FRF 59, 60. To the inner layer of FRF is sown a Velcro pad 61 to match the Velcro pad on the neck cover in Drawing 4. The noise insulation layer is made from two quarter inch thick layers of foam rubber 57, 58 which is commonly used for packing material. Both layers are a oval of two by three inches, the layer closer to the ear 58 has a one inch diameter circular hole in the centre. The two foam layers are held together by adhesive.

The hearing muffs 16 are easily removable during periods of conversation. As shown in Figure 25 drawing 11, five inch sguare pads of soft cloth 62 with velcro 63 attached to one side are provided to cover the neck cover's velcro pads and prevent chafing of the ears when the hearing muffs are not in pl,ace. As shown in Figure 21, Figure 22 and Figure 23 when the muffs are in place, the amount of hearing insulation is adjusted by both a primary and a s~C~n~l~ry means. The amount of hearing protection i9 prim~rily ~djusted by tte ve~r-r'~

~3~- 21 801 8~
positioning of the muffs upon the neckcover's Velcro pad 41 and by the positioning of the two inch wide Velcro strap on the neck cover 43. By varying the positioning of the neck covers Velcro strap, the neck cover offers varying pressure against the ear muffs to vary the noise insulation. The amount of hearing protection is secondarily varied by the ergonomic position of the head. Thrusting the chin forward of the neck will slide the ears slightly from under the muffs, to decrease hearing protection when in conversation or when listening to a delicate welding operation. Due to the variations in human anatomy and the eventual stretch of fabric under tension, it is the responsibility of the welding personnel and his tailor to ensure proper adjustment of both ear muff location and neck collar adjustment to ensure both adequate and variable hearing protection .

The ear chafing protectors 17 of Figure 25 are soft pieces of cloth with Velcro attached to one side of them which matches the hearing muff ,Velcro pads of the neck collar. When the hearing muffs are not in place it is n~c~C5~ry to install the ear chafing protectors to prevent chafing of the ears since the neck collar will otherwise compress the Velcro pads against the ears.

-~1- 2l8ol~4 It will be appreciated that the above description is related to the preferred ~ r~nt by way of example only. Many variations on the invention will be obvious to those in the f ield, and such obvious variations are within the scope o~ the invention as described and cl ~ d, wh-tll~r or n~t expresGI~ d~cri~ed.

Claims (30)

CLAIMS:

1. A laminated material for use as protection against the Soft X-ray component of electromagnetic radiation, said material comprising an intermediate radiation shielding material for attenuating a substantial portion of soft X-rays impinging thereon, sandwiched between an outer flame resistant material and an inner flame resistant material.

2. The laminated material of claim 1 wherein the radiation shielding material is selected from the group consisting of one or more layers of metallic foil, metallic sheeting, metallic plate, metallic mat, woven metallic wire, woven metallic ribbon or a weave of aluminum wire.

3. The laminated material of Claim 2 wherein the metal is selected from the group consisting of aluminum, magnesium, zinc, copper, cadmium, thallium, indium, cobalt, nickel, chromium, manganese, antimony, gallium, titanium, tantalum, niobium, thorium, zirconium, beryllium, and boron.

4. The laminated material of Claim 2 wherein the metal is aluminum.

5. The laminated material of claim 2 wherein the outer material is leather.

6. The laminated material of claim 2 wherein the outer material is a combination of leather and a flame resistant fabric.

7. The laminated material of claim 6 wherein the leather and flame resistant fabric are joined by a non-flammable flexible adhesive.

8. The laminated material of claim 7 wherein the adhesive is poly vinyl acetate.

9. The laminated material of Claim 3 wherein the metal is aluminum.

10. The laminated material of claim 3 wherein the outer material is leather.

11. The laminated material of claim 3 wherein the outer material is a combination of leather and a flame resistant fabric.

12. The laminate material of claim 11 wherein the leather and flame resistant fabric are joined by a non-flammable flexible adhesive.

13. The laminate material of claim 12 wherein the adhesive is poly vinyl acetate.

14. The laminated material of claim 2 wherein the radiation shielding material is aluminum and the outer and inner materials are formed of resin bound fibreglass.

15. A welding mask made of the laminate material of claim 14.

16. Apparel selected from the group consisting of aprons, breastplates, head coverings and gloves, made from the laminate of claim 1.

17. Apparel for the protection of welders from soft x-rays, said apparel made from the laminate material of claim 2.

18. A device for the instantaneously variable protection of hearing, said device consisting of a foam rubber object held against the head by fabric which wraps around the head from the back of the neck to the chin.

19. A prosthetic hearing protector as in claim 11 with a device for the protection of the ears from chafing due to hook and loop fastener pads, said device consisting of a piece of soft cloth attached to a hook and loop fastener pad which mates with an aggravating hook and loop fastener pad.

20. A laminate consisting of aluminum oxide fibre or thermodynamically similar refractory material held between two layers of fabric for the purposes of heat insulation.

21. A welding mask according to Claim 15 with a device designed to absorb the soft x-ray component of electromagnetic radiation while allowing the passage of visible light, said device comprising clear acrylic plastic or optically similar material cut to the desired shape.

22. The laminated mterial of Claim 1 wherein the radiation shielding material is inert on the macroscopic scale due to its reactivity upon the microscopic or atomic scale to the extent that the material is a metal capable of formation through the process of electrowinning.

23. The laminated material of Claim 22 the outer material comprises leather.

24. The laminated material of any one of Claims 1-13, 22 or 23 wherein the fire resistant materials are selected from the group consisting of glass fibre, mineral wool, stone wool, rock wool, a refractory fibre, fabrics of synthetic or natural fibres, canvas, cotton fabric, spunbounded polyolefins and leather.

25. A laminate comprising a refracory fibre or weave thereof, said refractory fibre being being chemically comprised of an oxide of a metal which in its solid state is inert on the macroscopic scale due to its reactivity on on the atomic or microscopic scale, said refractory material being held between two layers of impermeable fabric.

26. A laminate according to Claim 25 wherein the refractory material is aluminum oxide.

7. A laminate according to Clain 26 wherein the refractory fibre is adhered to the outer and inner layers by an adhesive.

28. A laminate according to calim 26 wherein the outer and inner layers are selected from the group consisting of leather and fire resistant fabric.

29. A laminate according to claim 26 wherein the inner and outer layers are both comprised of two layers of fabric, 35 the one of said layers being adhered to the innermost layer which is stitched to the refractory fibre and the other innermost layer.

30. A laminate according to Claim 25 wherein the outer and inner layers are stitched together.