US 3157885 A
Abstract available in
Claims available in
Description (OCR text may contain errors)
Nov. 24, 1964 M. J. o. LOBELLE AUTOMATICALLY PRESSURIZED FLYING SUIT Filed March 12, 1962 2 Sheets-Sheet 1 United States Patent 3,157,885 AUTGMATICALLY PRESSURHZED FLYING SUET Marcel Jules Odiion Lobelle, Slough, England, assignor to M. L. Aviation Company Limited, Siough, England, a British company Filed Mar. 12, 1962, Ser. No. 178,940 Claims priority, application Great Britain, Mar. 14, 1961, 9,312/61 Qlaims. (Cl. 2-2.1)
This invention relates to flying helmets, particularly those of the fully-pressurised type as disclosed in our copending application Serial No. 178,844, filed March 12, 1962. Such helmets when used in conjunction with fullypressurised suits allow the wearer to continue normal flight even after sudden cockpit decompression, for example, after breakage of the canopy at high altitude.
Such helmets must be fitted to the suit by a pressuretight connection and when this is done there is a tendency on increase in internal suit and helmet pressure for the helmet to rise on the wearers head by stretching the fabric of the suit around the neck. This is of course uncomfortable and provision has been made for fixing the helmet to the back and front of the suit by cords which include an adjustable strap so that the wearer can adjust the position of the helmet on change of pressure. Sudden decompression of the cockpit however automatically initiates immediate full pressurisation of the helmet, with the result that the helmet will rise very rapidly and probably injure the wearer, since he has no time to make the necessary manual adjustment.
According to the present invention apparatus for preventing such relative vertical movement includes two relatively movable members of which when in use the first is fixed to the suit and the second is connected to the helmet, and means responsive to the pressure in the helmet for maintaining the relative positions of the two members so that for any pressure within the helmet the helmet does not rise relative to the suit.
With such an arrangement even on emergency pressurisation of the helmet the tendency of the increased pressure to force the helmet upwards will be offset by the tendency of the second member to pull the helmet downwards, and consequently the helmet will not move.
Preferably the first and second members are a cylinder and a piston respectively, the pressure within the cylinde-r being controlled by the pressure in the helmet. Alternatively a bellows arrangement could be used.
The pressure in the cylinder is conveniently obtained from a source of air at a pfessure much greater than the pressure within the helmet and the pressure in the helmet controls a valve for regulating the supply of this high pressure air to the cylinder, and an exhaust valve for the cylinder.
The use of higher pressure air means that the dimensions of the cylinder and piston can be much smaller than if the pressure from the helmet was used directly, and consequently the apparatus may take the form of a small box sewn to the front of the pressure suit.
A particular example of apparatus in accordance with the invention will now be described in more detail with reference to the accompanying drawings in which:
FIGURE 1 is a schematic perspective view of part of the front of a flying suit and helmet;
FIGURE 2 is a schematic perspective view of the rear of the suit and the helmet; and
FIGURE 3 is a diagrammatic sectional view through the suit and helmet.
As will be seen from the first two figures the pilot Wears a helmet 1 and a suit 2 both of which can be pressurised if the cabin pressure in his aircraft falls below a certain value. To enable the helmet to be pressurised it is pro- 3,157,885 Patented Nov. 24, 1964 vided with a closing visor 3 which when in the closed position is sealed against a ledge 4 to make a pressuretight connection. As usual the helmet is provided with an oxygen mask 5. Formed round the lower part of the helmet is a flange 6 and this cooperates with a corresponding flange 7 forming a rigid ring at the top part of the neck of the suit. When flying the helmet is locked to the suit by means of these two flanges.
Fixed to the flange 7 are two eyelets 8 and 9 through which passes a cord 10. The free ends of this cord are clamped at 11 to a panel 12 which is sewn into the back of the pressure suit. The cord passes round a pulley 13 which is mounted to rotate in a sheave 14 connected to a strap 15 the length of which is adjustable.
The opposite end of the strap 15 is fixed to a piston 16 which is mounted to work in a cylinder 17 and is biased away from the top of this cylinder by a compression spring 18. The .piston and cylinder are enclosed in a box 19 which is stitched to the front of the suit and is also held in position by a pair of straps 20. The con tents of this box 19are shown schematically in FIGURE 3 and are indicated generally by the arrow 21.
FIGURE 3 also shows a schematic section through the helmet and the suit and it will be seen from this that the suit includes an inner bladder 22. This is sealed oil from the main body of the pressure suit and is connected to the interior of the helmet by a pipe indicated at 23. It is also connected by a further pipe indicated at 24 to a hollow expandable ring 25 surrounding the mans neck and stitched within the neck portion of the suit. When emergency pressurisation is necessary it is essential that the wearers head and abdomen be immediately protected while the rest of his body is able to withstand the drop in external pressure for a somewhat greater length of time. It is for this reason that the bladder 22 is provided and on emergency this bladder and the helmet together with the ring 25 are all pressurised at the same time before the pressurising air is fed into the main body of the suit. The ring 25 when inflated is elfective to seal off the interior of the helmet from the interior of the main part of the suit so that the high pressure air is unable to leak into the main part of the suit from the helmet. Suits with the second bladder are well known in the art and the bladders are commonly known as partial pressure bladders.
Movement of the piston 16 Within the cylinder 17 is controlled by high pressure air from a capsule 26 which is also housed within the box 19. This source could alternatively be fixed in the aircraft although if it is arranged this way there is a further connection between the pilot and the aircraft to be broken if the pilot has to be ejected. The supply of air from the reservoir 26 is controlled by a slide valve 27 which is able to move to the right as seen in FIGURE 3 to uncover an orifice 23 leading into a chamber 29 which also communicates with a tube 30 leading into the cylinder 17. Movement of the slide valve is controlled by a further piston 31 Working in a cylinder 32 and biased to the left-hand side of this cylinder as seen in FIGURE 3 by a compression spring 33. This piston has a shank 34 the end of which is a tight fit within a smaller diameter extension 35 of the cylinder 32 and from this shank there projects a rod 36 which passes through a sealing gland 37 between the extension 35 and the chamber 29 and is fixed at its other end to the movable member 27 of the slide valve.
The outlet from the cylinder 17 is by way of a pipe 38 into a chamber 39 having an outlet orifice til from which a pipe 41 leads into the main body of the pressure suit. The outlet orifice can be adjusted by movement of a needle 42 and this needle is carried on the end of a shank 43 which passes through a sealing gland 44 between the chamber 39 and a further chamber 45 and ends in a disc 46 which is free to move in an internal bore 47 formed in the sliding member 27. The disc is biased to the right as seen in FIGURE 3 by a compression spring 48 and it will be seen that the mechanical linkage between the valves is such that when the slide valve is fully closed the needle valve controlling the exhaust from the cylinder is fully open.
In an emergency high pressure air is immediately fed to the partial pressure bladder 22 the ring 25 and the helmet and this pressure will acton thepiston 31 to move it along the cylinder 32. It should be noted that although the pressurized air for achieving thi is obtained directly from the partial pressure bladder it is in fact at the same pressure as the air in the helmet so that it is correct to say that the position of the slide valve is controlled by the pressure in the helmet. When the pressure reaches a certain value the helmet as described will tend to rise and stretch the fabric round the neck of the suit. However, at the same time the slide valve will be opened by movement of the piston 31 so that high pressure air will be fed from the reservoir 26 to the cylinder 17. This willproduce a-'-downward force on the piston 16 and the slide valve is set so that for any pressure in the helmet this downward force is equal to the upward force on the helmet due to the increased pressure. Since these forces are balanced there will be no relative movement between the suit and the helmet. As the slide valve is opened the needle valve controlling the exhaust is closed and the linking of'these two parts makes it possible to maintain any required pressure in the cylinder 17 and provides a very sensitive control of this pressure. The exhausted air is not wasted since it is fed into the main body ofthe pressure suit thus helping to pressurise the remainder of the pilots body.
On restoration of normal cockpit conditions decompression of the suit will occur and the piston 31 will then be returned to its normal position under the action of the spring 33 so closing the slide valve and opening the needle valve. Thus as the upward pressure on the helmet decreases the downward pressure on the piston 16 decreases so that once against relative vertical movement between the helmet and the suit is prevented. It will be seen that this system maintains the helmet and the suit in their relative positions whatever maybe the pressure and although an over-riding manual control'is provided in the form of the adjustable strap this is usually only used when the suit is first put on.
It is, of course, possible to supply a number of different valve systems which will have the same eifect as the system illustrated and indeed a number of modifications can be made such as the provision of a bellows'in place of the piston and cylinder 16 and 17 as already mentioned.
1. In combination with a pressurized flying suit including helmet and body portions, apparatus for preventing relative vertical movement between said helmet and body portions, comprising: a cylinder having an inlet and an outlet, said cylinder forming a first one of two relatively movable members; a piston mounted for movement within said cylinder and forming a second one of said members, one of said members being fixed to said suit and the other of said members having a connection to said helmet; a source of air at a pressure greater than the pressure within said helmet; a first valve connected between said source and said cylinder inlet and responsive to said helmet pressure for regulating supply of said air from said source to said cylinder; a second valve also responsive to helmet pressure and connected to said outlet of said cylinder for regulating the rate of exhaust of air from said cylinder, said response of said valves being such that said members maintain their relative positions whatever the value of said helmet pressure so that said helmet does not rise relative to said suit.
2. Apparatus in accordance with claim 1 and including a mechanical linkage between said first and second valves, said linkage being such that as said helmet pressure increases, the air supply to said cylinder is increased, and the rate of exhaust of air from said cylinder is decreased.
3. Apparatus in accordance with claim 1 wherein said connection comprises a cord fixed to the hack of said suit, connected intermediate its length to said helmet,
and adjustably connected to said other of said members by an adjustable strap, and wherein a box fixed to the front of said suit houses said members.
4. Apparatus in accordance with claim 3 including a pulley mounted on said adjustable strap and wherein said helmet includes a pair of eyelets, one connected to each side thereof and wherein said cord is fixed at both ends References Cited by the Examiner UNITED STATES PATENTS 2,973,521 3/61 McGowan 22.1 3,042,926 7/62 Shepard 22.l
FOREIGN PATENTS 836,925 6/60 Great Britain.
JORDAN FRANKLIN, Primary Examiner.
THOMAS HICKEY, Examiner.