Respiratory masks

Nov. 26, 1957

Filed Feb. 14, 1955

J. E. GABB ET AL 'RESPIRATORY MASKS

2,814,293

Sheets-Sheet 1

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Inventors

Attorney

Nov. 26, 1957 J. E. GABB ETAL

RESPIRATORY MASKS

Filed Feb. 14, 1955

2,814,293

Sheets-Sheet 2

<img file="US2814293A_D0002.tif" />

Inventors

Attorney

Nov. 26, 1957 j. e. gabb etal 2,814,293

RESPIRATORY MASKS Filed Feb. 14, 1955 4 Sheets-Sheet 3

<img file="US2814293A_D0003.tif" />

Nov. 26, 1957

2,814,293

J. E. GABB ET AL

RESPIRATORY MASKS

Filed Feb. 14, 1955

Sheets-Sheet 4

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<img file="US2814293A_D0005.tif" />

Inventors (d.

Attorney

United States Patent Office p_atented

2,814,293

RESPIRATORY MASKS

John Escott Gabb, Eastleigh, and Avon Spurgin Lucking, Feltham, England, assignors to The British Overseas Airways Corporation, Brentford, England

Application February 14,1955, Serial No. 487,894

Claims priority, application Great Britain February 16, 1954

Claims. (Cl. 128—146)

This invention relates to respiratory masks and particularly to the way in which the masks can be attached to a harness upon the head of the wearer, so that they are held firmly against the face without any danger of leakage round the edges of the mask.

Particularly in oxygen masks for airscrews, provision has to be made for a microphone, and the harness also carries head-phone ear-pieces. The wearer should be able to fit and remove the mask easily and quickly, and he should still be able to speak into either a mask microphone or a secondary microphone even when the mask is hot in position on his face. In usual arrangements the mask dangles from one side of the helmet or harness and has to be pulled into position by the hand if the microphone in the mask is to be used. This is inconvenient, since the pilot or other occupant of an aircraft may, at any particular moment, have both hands occupied. Also, existing forms of flexible flying helmet form an unsatisfactory structure to which to attach a pressure breathing mask.

J The present invention enables the mask to be held perfectly firmly by a head harness if desired instead of a flying helmet. This greatly increases the comfort of the wearer, particularly when flying in hot climates, by reducing the tendency of the head to sweat, and disturbance to the hair, and also reduces the risk of scalp infection which occurs when a helmet is worn for a long time, particularly in bad conditions. The mask may be clamped into position on the face quickly, and when the mask is not in use, it hangs on the chest immediately beneath the wearer’s chin, so that there is no unbalanced weight on the head and the mask is ready to be fitted at any moment.

For flying at great heights above, say 35,000 feet, it is necessary for a more complicated form of oxygen mask known as a pressure breathing mask to be provided and this must be held very firmly to the face of the wearer. However, below these heights, it is not necessary for such a strong pressure to be exerted and we have, therefore, evolved an arrangement by which the mask can be held to the wearer’s face with alternative pressures which can easily be selected, so that below extreme heights, only the lighter pressure can be used with consequently greater comfort to the wearer.

According to the invention, the face-piece of a respiratory mask is connected to a head harness by a pair of links on each side. One link is hinged to the face-piece and is pivoted at its other end to the other link which is hinged to the head harness. The arrangement is such that when the mask is worn the two links at each side project forwards from these hinges, and the axes joining the pivots in each of the two links are nearly parallel, a stop being provided to arrest the breaking of the toggle so formed on one side of the parallel, dead centre, positiori of the axes. The links may be hinged together by a short connecting member in which the links are journalled. When the wearer wishes to remove the mask, he pushes this member upwards past the dead-centre posi2 tion breaking the toggle so that the mask drops from his faces and rests on his chest hanging from both ear-pieces by the two links. In this way, in any emergency, the mask may be placed in position and secured to the wear5 er’s face in two seconds.

To provide for two different pressures the relative positions of the pivotal axes of the links in the short connecting member may be varied either by adjusting the angle of the member or by providing a movable journal 10 for one of the links in the member.

Two examples of masks according to the invention, are shown in the accompanying drawings in which:

Figure 1 is a side view of a mask providing one pressure for medium altitude flying in position on the wearer;

Figure 2 is a perspective view of the mask shown in Figure 1;

Figure 3 is a similar view to Figure 1 of a high altitude mask having two alternative pressures;

Figure 4 is a perspective view of the mask shown in 20 Figure 3;

Figure 5 is a perspective view, and

Figure 6 is a plan view of an alternative arrangement for changing over the pressures in the mask of Figures 3 and 4.

In Figures 1 and 2, the mask comprises a rubber facepiece 1 moulded to the face of the wearer and provided with an attachment 2 for an oxygen pipe, and a microphone controlled by a switch 3. The breathing valves and internal arrangements of the mask form no part of 30 the invention and are not illustrated. The rubber facepiece 1 has a series of integrally moulded lugs 4 (in Figure 2) through which pass straps 5 by which attachment pieces 6 are secured to the face-piece. Two compression links are formed by the arms of a U-shaped ³⁹ rod 7 which is pivoted at each end to one of the attachment pieces 6 at 8, and the center of which passes through one of two parallel holes in a metal sleeve 9. The distance between the arms of the U-shaped rod 7 decreases from the points 10 to the attachment points 8 so that 40 at the points 10, the U-shaped rod 7 is wider than a Ushaped rod which passes through the second hole in the sleeve 9 and forms the tension link 11 on each side. Each end of this rod is threaded into an adjustable turnbuckle 12 at the other end of which is an eye 13 en⁴⁹ gageable in a spring catch 14 on an attachment plate 15 which is rotatable on the moulded housing 18 of the ear-piece 16. After the turn-buckles 12 have been adjusted, they can be locked by means of lock nuts 17. The ear-pad ring 16 is anatomically designed to give the ⁹⁹ greatest possible comfort with the maximum exclusion of external noise.

The tension links 11 are longer than the compression links 7, and the parts 7, 9 and 11 form on each side of the mask a toggle linkage capable of holding the face ⁹⁹ piece 1 firmly against the face of the wearer. In the working position, the two links 7 and 11 at each side project forwards from the hinged connections 8 and 13 respectively and the axes joining the pivots of the links are nearly parallel as shown in Figures 1 and 3, the rela⁶⁰ tively wide parts 10 of the U-shaped rod that forms the links 7 acting as a stop to prevent further downward movement of the links 11 relatively to the links 7 after they have passed through the parallel or dead-centre position. The linkage is finally tightened by rocking the ⁶⁹ sleeve 9 anti-clockwise from the position shown in Figures 1 and 3 so as to increase the compression of the link 7. When the wearer wishes to remove the mask he first pushes the front edge of the member 9 upwards past the dead-centre position and into the position shown in 70 Figures 1 and 3 thus loosening the main toggle. The front ends of the links 7 and 11 can then easily be lifted . so as to break the main toggle and allow the mask to

2,814,283 ³ drop from his face and rest on his chest hanging from both ear-pieces by the two links 11.

The moulded housing 18 of each ear-piece has an earphone 19. A bearing 20 for an; arm 21 at the end of which is a microphone capsule :22 may be attached .to the housing of either ear-piece. The arm: 21; is curved so that.when it is pulled forward, the capsule is.supp.orted immediately in front of the face of the wearer and thus provides a microphone when the mask is not imposition on the wearer’s face. The bearing 20 can be adjusted on the housing 18 by slackening a lock nut 23 and sliding to and fro the plate 24 on which the bearing 20 is mounted. The ear-pieces are supported on a pair of padded flexible steel headbands 25 connected at each ;end by a cross-piece 26 from which two knurled wires 27 pass through vertical bores in the housing 18. The housing and ear-pieces can thus be adjusted up and down in relation to the headbands. The two attachment plates 15 are connected by an adjustable counter-pressure band 28 which, as shown , in Figure 1, passes round the back of the head of the wearer and takes the pull of the linkage connecting the harness to the face-piece. The microphone and headphone leads 29 run to the housing 18 in the left hand ear-piece and from there a lead 30 runs to a plug . 31 which can be connected alternately to a plug 32 on a lead 33 running to the microphone in the facepiece 1 or to a plug 34 on a lead 35 running to the microphone capsule 22. Flexible leads 36 run through the padded covering of the headbands 25 to the right hand ear-piece.

In Figures 3 and 4, the tension link 40 is similar to the tension link 11 in Figures 1 and 2, but is journalled in a short connecting member 41 formed with a finger piece 42. The short compression links 43 are pivoted directly at 44 to a fretted plastic support 45 for the moulded rubber face-piece 46. The short compression links do not extend outwards beneath the tension links 40 as in the previous example, but are provided with small hooks 47 which prevent the tension links 40 dropping appreciably below the compression links 43. The short connecting member 41 is movable through a dead centre position in which its hinged connection to the compression links is disposed directly behind its hinged connection to the tension links to either of two limiting positions which give different degrees of pressure between the face piece and the wearer’s face. In the position shown in Figures 3 and 4, the maximum pressure is exerted. When less pressure is required, the finger piece 42 is raised until the tension links 40 bear upon stop lugs 48 on the compression links 43, in which position the centre of the tension link is more nearly above the centre of the compression link so that less pressure is exerted.

In Figures 5 and 6, the sleeve and finger pieces 41, 42 are replaced by two members 50, 51 which can be moved towards and away from each other to alter the pressure. The member 51 carries a pair of pillars 52, 53 which slide in bores 54 in the member 50 and thus maintain the two members in alignment. A shaft 55 is journalled in both these members and is parallel to the pillars 52, 53. This shaft has a helical groove 56 in which a pin 57 in the member 50 engages so that, as the shaft is rotated by means of a hand lever 58, this pin is moved along the groove, thus moving the member 50 towards and away from the member 51. In the position shown, the maximum pressure is exerted on the face-piece.