GB2264647A

GB2264647A - Fastening inner mask inside hood

Info

Publication number: GB2264647A
Application number: GB9302741A
Authority: GB
Inventors: Bengt Oesterback; Stefan Sandbacka
Original assignee: Kemira Oyj
Current assignee: Kemira Oyj
Priority date: 1992-03-06
Filing date: 1993-02-11
Publication date: 1993-09-08
Anticipated expiration: 2013-02-11
Also published as: FI921002A0; FI96279C; DE4304891A1; FI921002A; GB2264647B; SE508688C2; SE9300707D0; SE9300707L; FI96279B; GB9302741D0; DE4304891C2

Description

1 2264647 Respiratory protective device with a hood and a filter attached

to the hood This invention relates to a respiratory protective device comprising a hood made of flexible material, a filter secured to the front of the hood, connecting the inside and outside of the hood, an inner mask connected to the filter and extending to the inside of the hood, and a set of strings (5) for pressing the inner mask gas-tight around the mouth and the nose of the wearer, wherein the set of strings is secured to the part of the inner mask extending inside the hood and arranged to run essentially entirely inside the hood.

Respiratory protective devices are known in the art which consist of a gas-tight hood which resists heat and/or chemicals and has a gas filter attached to a suitable place. The hood is so dimensioned that it fits heads of various sizes and persons of various ages in such a way that the lower edge of the hood can be tightened against the neck of the wearer as well. When the hood is not transparent, it is generally provided with a window which must be of a material just as heat and chemical resistant as the rest of the hood material. The filter is hermetically attached to the hood and fitted in such a way that it sits in front of the wearer's nose and mouth, whereby at least the inhaling is carried out through the filtering unit. This is best done with the aid of an inner mask connected to the filter and extending inside the hood and which is pressed gastight against the surface of the wearer's face surrounding the mouth and the nose.

When a hood is used as a respiratory protective device, provided with an inner mask in this way, a set of strings is always required to press the inner mask gas-tight around the mouth and the nose. The sets of strings up to now have been running outside the hood, whereby they have been subjected to the same severe conditions, for instance heat and corrosive materials, against which the respiratory protective device is meant to protect its wearer.

2 Thus a respiratory protective device is already known wherein the set of tightening strings of the inner mask, going behind the head runs outside the hood and is attached to the hoop ring between 'the filter and the hood. This kind of a solution requires that the set of strings must be refractory and/or chemical resistant, whereby it generally is not sufficiently flexible and soft.

Consequently, the purpose of the present invention is to provide a respiratory protective device consisting of a hood, filter and an inner mask, the inner mask of which can be pressed around the wearer's mouth and nose without a set of strings running outside the hood. A further purpose of the invention is to provide a respiratory protective device of said type which can be fitted is over the wearer's head essentially without making the impractical and unsafe steps where the inner mask is pressed around the wearer's mouth and nose by fitting and tightening its set of strings by hand.

Claims

The above objects are now achieved by a new respiratory protective device

solution which is mainly characterized by what is said in the characterizing part of Claim 1. Thus it has been realized that said set of strings operates and is protected as well when it comprises flexible strings and is further secured to the inner surface of the hood.

The hood of the respiratory protective device according to the invention is so dimensioned that it fits well heads of various sizes and persons of various ages. Its material can be of any flexible material depending on the environment which the hood is supposed to protect its wearer against. Generally, the hood is made of gas-tight, heat resistant, and flexible material, whereby it is preferred to use, as the hood material in high temperatures, a piece of refractory fabric which may be coated with reflecting material. If the hood material is not transparent, the hood can comprise a window in the front thereof.

In order to provide a gas-tight seam between the hood opening 3 and the wearer's neck, the hood is preferably provided with a tight collar solution. In order for the shape of the hood to follow the wearer's head in the best possible manner, the inner surfaces of the hood can be provided with separate flexible strings to provide and maintain the proper shape of the hood.

The filter used together with the hood can be any suitable filter which protects one against the environment. The filter can be a detachable one, but disposable respiratory protective devices are often used for safety purposes at present, comprising a filter which is permanently attached to the hood.

The respiratory protective device according to the invention further consists of an inner mask extending inside the hood and connected to the filter. The inner mask resembles a half mask the flexible material of which is pressed, in a gas-tight manner, against the skin surface area of the wearer, surrounding the mouth and the nose. Thus inhaling only occurs through the filter and exhaling is preferably effected through an exhale valve.

As already mentioned, in order to press the inner mask around the wearer's mouth and nose, a set of strings is required which is essentially entirely inside the hood in the solution according to the invention. The most common string solution is generally one in which the string or the set of strings runs from the inner mask along one cheek of the wearer, goes around the back of the head and/or the top of the head and further along the other cheek of the wearer and back to the inner mask.

When the string in the solution of the present invention is essentially entirely inside the hood, it can be difficult to fit in place if the set of strings is not attached to the inner surface of the hood. Thus the string or the set of strings is preferably attached to the middle of the back portion of the hood, i.e., the portion which covers the wearer's back of the head and/or the top of the head.

Another solution for keeping the set of strings in place on the inner surface of the hood is to arrange guiding links to the 4 inner surface of the hood, through which the strings of the set can run. This solution can be joined to the above-mentioned securing solution of the strings or the solution can be used alone. The use of the guiding links.allows the strings of the set to move through the guiding links, which occurs when the strings are being tightened and when using elastic strings.

When using a symmetric set of strings which is fitted in accordance with the wearer's head, it is ideal to secure the strings of the set to the center line between the uppermost and the most posterior point of the inner surface of the hood and provide the inner surface of the hood with guiding links situated by the cheek bones of the wearer, through which the strings of the set connected to the inner mask can freely move is when they are tightened and when they are flexible.

According to a preferred embodiment of the invention, the set of strings consists of a fixed loop made of a flat string, two essentially equally long flat strings extending from its opposite ends and secured at their ends to the portion of the inner mask extending inside of the hood. Both curves of the loop of a set of strings like this are preferably secured at their middle parts to the middle of the back part of the hood.

Another problem associated with the use of the inner string is the tightening of the set of strings to the suitable length and tightness for each wearer. This difficulty is avoided in the present invention by manufacturing the set of strings or a part of it from flexible strings. The strings are preferably different with respect to their flexibility, and it is especially advantageous if the strings of the set consisting of the loop and two inner mask strings, secured to the inner mask are more flexible than the loop strings.

In the following, the invention is described in more detail with reference to the appended drawings, where:

Fig. 1 represents a partly cut-off side view of the respiratory protective device of an embodiment of the invention, mounted over the head of the wearer, and Fig. 2 represents a schematic view of the inner string of an embodiment of the invention.

The respiratory protective device represented in Fig. 1 is provided with reference number 1. It comprises hood 2 made of flexible material, having filter 3 which connects its inside and outside secured to the front thereof, the filter being in contact with the inner mask 4 extending inside hood 2. The respiratory protective device is provided with set of strings 5 for pressing the inner mask 4 gas-tight around the mouth and the nose of the wearer.

According to the invention the set of strings 5 is secured to part 6 of inner mask 4 extending inside hood 2 and arranged to run entirely inside hood 2.

The parts of the set of strings 5 running over the back and the top of the head appear to press hood 2 against the head in Fig. 1, because hood 2 seems to be touching the head at said spots.

However, this is not the case because the effect is due to the fact that the strings of set 5 extending over the back and the top of the head are secured to hood 2 at the spots indicated in the Figure, the spots being located inside hood 2 on the intersecting line of hood 2 and the symmetry plane of the wearer's head.

Guiding links 7 and 71 are arranged on the inner surface of hood 2 against the cheek bones of the wearer, the strings of set 5 going therethrough.

Set of strings 5 is illustrated in more detail if Fig. 2. It consists of fixed loop 8 and 81 made of a flat string, two essentially equally long and flat pieces of strings 9 and 91 extending from its opposite ends. These two flat pieces of strings 9 and 91 can be secured and tightened at their ends to inner hood 4 and especially to its part 6 extending inside hood 2. The tightening is illustrated in Fig. 1. Fig. 1 further presents visible strings 8, 81 and 9 of the set of strings 5 in Fig. 2, in order to present the mounted set of strings 5.

6 As already mentioned, the set of strings illustrated in the Figures preferably comprises flexible strings, whereby the flexibility of the strings is preferably different. Strings 9 and 91 secured to part 6 of inner mask 4 extending inside hood 2 are preferably more flexible than loop strings 8 and 81, particularly because when the head is turned, the inner mask would press around the mouth and the nose due to cheek strings 9 and 91, using constant force, while loop strings 8 and 81 would maintain an essentially constant grip on the head.

h 7 C L A I M S 1. A respiratory protective device comprising a hood made of flexible material; a filter secured to the front of the hood and connecting the inside and outside of the hood; an inner mask connected to the filter and extending to the inside of the hood; and a set of strings for pressing the inner mask gas-tight around the mouth and the nose of the wearer, wherein the set of strings is secured to the part of the inner mask extending inside the hood and arranged to run substantially entirely inside the hood, and wherein the set of strings comprises flexible strings, and is further secured to the inner surface of the hood.
2. A respiratory protective device according to claim 1, wherein the set of strings is further secured to the middle of the back and/or upper part of the hood.
3. A respiratory protective device according to claim 1 or 2, including guiding links arranged to the inner surface of the hood, through which links the strings of the set of strings run.
4. A respiratory protective device according to claim 1, 2 or 3, wherein the set of strings consists of a fixed loop made of a flat string, and wherein two substantially equal length flat strings extend from the opposite ends of the loop and are secured at their ends to the part of the inner mask extending inside the hood.
5. A respiratory protective device according to claim 2, taken together with claim 4, wherein both curves of the loop of the set of strings are secured to the middle of the back part of the hood in the middle thereof.
6. A respiratory protective device according to any one of the preceding claims, wherein the strings are of different flexibility to one another.
7. A respiratory protective device according to claim 6, when appendant to claim 4 or 5, wherein the strings secured to the inner mask are more flexible than 8 - the loop strings.
8. A respiratory protective device according to any one of the preceding claims, wherein the inner surface of the hood comprises separate flexible strings for providing and maintaining a suitable shape for the hood.
9. A respiratory protective device constructed and arranged substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.