US3239843A - Flying helmets - Google Patents

Description

March 15, 1966 M. J. o. LOBELLE 3,239,843

FLYING HELMETS Filed March 12, 1962 '7 Sheets-Sheet 1 lnuenlor JTV Attorney;

March 15, 1966 M. J. o. LOBELLE 3,239,343

FLYING HELMETS Filed March 12, 1962 7 Sheets-Sheet 2 [nvenfor March 15, 1966 M. J. o. LOBELLE 3,239,843

FLYING HELMETS Filed March 12, 1962 '7 Sheets-Sheet 5 u r in Jim Attorney 5 March 15, 1966 M. J. o. LOBELLE 3,239,343

FLYING HELMETS Filed March 12, 1962 7 Sheets-Sheet 5 LJIYIiKIIILZ'TIiiKl' W March 15, 1966 M. J. o. LOBELLE FLYING HELMETS 7 Sheets-Sheet 6 Filed March 12, 1962 Inventor March 15, 1966 M. J. o. LOBELLE FLYING HELMETS 7 Sheets-Sheet 7 Filed March 12, 1962 lnuenlor United States Patent 3,239,843 FLYING HELMETS Marcel Jules Odilon Lobelle, Slough, England, assignor to MJL. Aviation Company Limited, Slough, England, a British company Filed Mar. 12, 1962, Ser. No. 178,344 Claims priority, application Great Britain, Mar. 14, 1961, 9,316/ 61 9 Claims. (Ci. 2--6) This invention relates to flying helmets for use in conjunction with fully-pressurized suits. Such equipment allows the wearer to continue normal flight even after sudden cockpit decompression, for example after breakage of the canopy at high altitude.

Such helmets have a rigid shell which extends over the face and the top of the head of the wearer and is formed with an opening in front of the wearers eyes. When the helmet has to be pressurised this opening must be closed and sealed and for this purpose a transparent visor is provided. Previous visors have been mounted on side arms pivoted at the sides of the helmet so that they can move between the closed position and an open position above the opening.

According to the present invention the visor is substantially lune-shaped and is mounted at each side on pivots within the shell so that it can move between an open position in which it is stored within the shell above the opening, and a closed position in which its lower edge is in sealing contact with a part formed within the shell below the opening, and the helmet also includes a hood of flexible pressure-tight material which is sealed along the upper edge of the visor, round the pivots, and to the shell so that when the visor is open the hood is folded behind it and when the visor is closed the hood is open and constitutes a pressure-tight connection between the upper edge of the visor and the shell.

In previous constructions the visors have been mounted on side arms pivoted outside the shell, and in order to seal off the opening they have had to move down and back, but since the upper and lower edges of the visor of the present helmet extend round within the sides of the helmet almost to the pivot points of the helmet, sealing can be accomplished simply by a downward rotation thus allowing the visor operating mechanism to be made much simpler and more reliable. This, together with the seal formed by the hood and the simple reliable seal now able to be provided for the lower edge of the visor, make the whole process of pressurisation much more efiicient.

Preferably the hood is also susbtantially lune-shaped with the points of the lune cut off at each side so that each side of the hood is concave, and each arc is defined by an enlarged rim seated in a groove formed in a member at least partly surrounding the respective pivot so that when the visor is closed the rim cooperates with the groove to form a pressure-tight seal. Conveniently this cooperation is obtained by forming the groove narrower at one end so that when the visor is closed the rim is forced along the groove towards the narrow end and is compressed to form a seal although alternatively the rim and the groove could be so shaped that they form a labyrinth seal to stop the air escaping.

Preferably the sides of the visor are fixed to side plates which are pivoted at corresponding points on each side of the helmet, and the visor is biased to a closed position by a tension spring fixed at one end to an extension of one of the side plates on the opposite side of the pivot to the visor, passing round the back of the helmet within the shell, and fixed at its other end to a similar extension of the other side plate. The helmet may be retained in the open position by a lever bearing on the side plate and the lever may be arranged so that it can be moved out of contact with the side plate to allow the visor to close either manually or under the control of means responsive to either sudden drops or sudden increases of external pressure.

A helmet according to the invention will now be described in more detail by way of example with references to the accompanying drawings in which:

FIGURE 1 is a side elevation of the helmet with the visor open;

FIGURE 2 is a front elevation of the helmet with the visor closed;

FIGURE 3 is a section on the line III-III of FIG- URE 2;

FIGURE 4 is a plan view of the helmet with the visor closed;

FIGURE 5 is a lateral cross-section through the visor;

FIGURE 6 is a fragmentary side elevation showing a part of FIGURE 1 on a larger scale but with the visor closed;

FIGURE 7 is a section on the line VII-VII of FIG- URE 6;

FIGURE 8 is a cross-section taken through one of the pivots on the line VIII-VIII of FIGURE 6 with the visor closed;

FIGURE 9 is a cross-section through the other of the pivots with the visor open;

FIGURE 10 is a schematic side elevation of part of the control mechanism for the visor;

FIGURE 11 is a plan view corresponding to FIGURE 10;

FIGURE 12 is a section on the line XII-XII of FIG- URE 10; and

FIGURE 13 is a section on the line XIII-XIII of FIGURE 2.

As shown in the figures the helmet is formed with a rigid shell 1, made of resin-bonded glass fibre and this covers the wearers head except for a front opening 2 extending roughly from the wearers forehead to his chin. A further part 3 of the shell is built up within the main outline and extends across the wearers mouth. This part has an oxygen mask 4 fixed to it as described in copending application Serial No. 178,812, filed March 12, 1962, now Patent No. 3,167,069. The helmet is worn with a fully pressurised suit the neck of which is shown at 5 and it is connected to the suit by a lock shown generally as 6 which prevents relative vertical movement of the helmet and the suit and yet allows relative rotation of the two.

The helmet is designed for use with a fully pressurised suit having a partial pressure bladder which surrounds the wears abdomen within the suit. In an emergency it is essential for the wearers abdomen and head to be pressurised immediately and the rest of the body can withstand the pressure drop for a slightly longer period. The helmet is further connected by a pipe 6' leading out of the helmet to the partial pressure bladder and 1. these are both connected to a supply of compressed air within the aircraft. On pressurisation the bladder and helmet are pressurised first and no compressed air is fed into the main body of the suit. However, the partial pressure bladder extends only a short way up the wearers breast bone and does not surround the body right up to the neck. When the helmet is pressurised therefore the pressurising air would have the effect of starting to pressurise the whole suit by leaking down past the neck of the wearer. To prevent this happening an inflatable tube (not shown) is sewn inside the neck of the suit closely surrounding the wearers neck and is also connected to the helmet and the bladder so that as pressurisation is commenced the tube inflates and forms a seal round the wearers neck so stopping leakage from the helmet. When the helmet is pressurised there will be a tendency for the helmet to rise up stretching the fabric round the neck of the suit. This can be prevented by apparatus responsive to pressure in the helmet for holding the neck of the suit down against this upward force and such apparatus is preferably as described and claimed in co-pending application Serial No. 178,940, filed March 12, 1962, now Patent No. 3,157,885. Cords 8 leading to this apparatus are passed through fair leads 9 connected to the part of the lock 6 which is fixed to the fabric of the suit.

In order to pressurise the helmet the opening 2 must, of course, be closed and this is effected by means of a visor 10 which is normally stored within the shell above the opening but is pivoted at both sides of the helmet so that it can be moved downwardly to the position shown for example, in FIGURES 2 and 3 to close the opening. The visor is formed of two transparent sheets 11 and 12 separated from each other so that a layer of air 13 is trapped between them to prevent mist forming and thus obscuring the wearers vision. A system of wires may be enclosed in this space so that it can be electronically heated. Along the lower edge of the visor the sheets 11 and 12 are sealed one on each side of a plate 14 and the edges of these sheets as shown in FIGURE 3 project slightly beyond this plate. The plate 14 is actually part of a continuous plate which extends round the full periphery of the two sheets and has the sheets sealed to the inside and outside surface of it respectively along its whole length. The part 3 of the shell is built up within the main outline of the shell so as to leave a ledge 15 extending round the bottom of the opening and being continued within the shell almost back to the wearers cars. A flexible O-section sealing ring 16 is fixed along the edge of the visor between the parts of the sheets projecting beyond plate 14 and when the visor is in the closed position this ring is trapped against the ledge 15 thus forming a pressure-tight seal so that air cannot leak from the helmet to the outside atmosphere.

It has already been stated that it is necessary for the helmet to be pressurised almost immediate in the case of emergency and that the main air supply for this is obtained from a cylinder within the aircraft. The build up of pressure can be increased, however, if the pressure of the oxygen fed to the mask is increased and some of this oxygen is allowed to leak out into the space within the helmet. The supply of oxygen to the mask is by way of a pipe which is enclosed in a coupling hose 7 and leads from this by way of a pipe 17 within the helmet to an intake regulating valve which is not shown in detail in the drawings. The oxygen mask is formed with a central orifice 1S communicating with a channel 19 through the part 3 of the rigid shell. The channel may be closed by a plate 20 hinged above it at 21 to the part 3 and having a spring tongue 22 for engaging a corresponding recess in the part 3 below the channel. This forms a door which can be swung open into the position shown in FIGURE 1 and through which the wearer may feed himself when not using the oxygen supply. The door is positioned to lie within the visor when closed as shown in FIGURE 3, and indeed when the visor closes it hits the door if it is open and automatically forces it into the closed position. The plate 20 incorporates a flap value and for this has a boss 23 projecting from it towards the wearers mouth, this plate having an inturned flange 24- round its inner edge. The plate 25 is free to slide within the boss 23 and is normally seated against the flange by means of a leaf spring 26 bearing at one end on the plate 25 and at the other end on the plate 20. The spring is such that under normal conditions, when the pressure within the oxygen mask is slightly greater than that outside the mask is sealed off from the outside atmosphere so that there is no oxygen leakage. In an emergency, however, when the cabin pressure falls rapidly and the pressure Within the oxygen mask is increased as has been described the plate 25 will be forced away from the flange 24 thus allowing oxygen to leak past it and flow into the space within the helmet. This flow from the mask thus supplements the flow from the main compressed air source.

A partition 27 is formed with the shell of the helmet and extends about half way down the back of the helmet and below the position of the wearers ears at each side as shown in FIGURE 1. This partition thus forms a compartment 28 round the top of the helmet and it will be seen that the visor when in its open position is stored within this compartment. The inner surface of the partition carries a pad 29 which is resiliently biased away from the partition by a series of springs such as 30. The helmet can thus fit snugly on top of the wearers head and since a separate compartment is defined for the visor no discomfort is caused to the wearer by movement of the visor. The partition is substantially lune-shaped and its rear edge 31 turns outwardly from the centre of the helmet. At U-shaped member 32 is fixed to the outer surface of the compartment and to the inner surface of the shell to position the partition the required distance within the shell and also to support it in position. The compartment is also supported in the region of the pivots at both sides of the helmet.

At its upper edge the two sheets 11 and 12 forming the visor are spaced by an upper part 33 of the continuous plate 14 but the edges of the sheets do not project beyond this part of the plate as they do along the bottom of the visor. The part 33 is formed with a series of tapped holes along its length and these holes receive bolts such as 34 which pass through an inwardly turned portion 35 of a hood 36 made of pressure-tight material. The front edge of the hood is sealed along the whole length of the upper edge of the visor and when the visor is in the open position as shown in FIGURE 3 the hood extends back within the compartment to its rear edge 37 along which it is sealed to the inside of the shell 1 by a sealing plate 38. The hood is also substantially luneshaped and the sealing plate 38 extends substantially round half a great circle of the shell ending at each end at a point 39 in the region of the wearers car. When the visor is in the open position the hood is folded behind it in the manner of a pram hood within the compartment as shown in FIGURE 5 and in broken lines in FIGURE 3. When the visor is closed the hood opens out and thus forms a pressure-tight seal between the upper edge of the visor and the inside of the shell.

As previously mentioned the two sheets 11 and 12 of the visor are sealed along their edges on opposite sides of the plate 14. At each side of the visor the two sheets are rounded off as shown at 40 while at these sides the plate 14 is formed with a V-shaped extension 41 which thus projects below the two sheets. This extension 41 at the right-hand side of the helmet is held between two plates, an inner one 42 and an outer one 43 by a series of bolts such as 44. At the left-hand side of the helmet a similar extension 45 of the plate 14 is held between inner plate 46 and an outer plate 47 by a similar series of bolts. The two inner plates 42 and 46 will be termed side plates throughout the remainder of the specification and claims. The side plate 42 is pivoted about a shaft 48 passing through the right-hand side of the rigid shell of the helmet while the side plate 4-6 is pivoted about a shaft 49 passing through the left-hand side of the shell the two shafts 48 and i9 being concentric. Although the outer plates 43 and 47 in each case stops short of the shaft it nevertheless projects beyond the lower edge of the respective extension 41 or 45 of the plate 14. On the right-hand side of the helmet the shell I has bolted to it by bolts 50 a part having an inwardly extending boss 51 having a bore 52 through which pass parts mounted to rotate about the shaft 48 which will be described in more detail later. Over part of its circumference the boss is formed with a shoulder 53 and a part 54 of the sealing ring 16 is held in the rectangle which is formed between the side plate 42, the extension of the outer plate 43, the lower edge of the projection 41 from the plate 14, the shoulder 53 and a part 55 of the outer surface of the boss. An identical arrangement is provided at the left-hand side of the helmet and the corresponding parts on the left-hand side of the helmet are denoted by primed corresponding reference numerals. Dealing specifically with the right-hand side of the helmet although the left-hand side is identical in this respect, and referring to FIGURE 5 it will be seen that the sealing ring at 54 is looped away from the boss 51 when the visor is open. It will be seen from FIGURE 5 that the bottom part of the extension 41 does not extend the full way round the pivot so that the sealing ring at 54 is only in contact with this over a part of its length. The looped part of the ring is put in contact with the extension and is fixed to the side 56 of the hood and it will be seen from FIGURE 5 where at 54 the sealing ring abuts the hood that although the hood is substantially lune-shaped the points of the lune are cut off so that the edges of the hood are arcuate and are concave. Since the sealing ring is fixed along the arcuate edge of the hood it thus defines a sealing rim.

When the visor is open and the hood is folded behind it as shown in FIGURE 5 the sealing ring as stated is looped away from the boss. When the visor is closed, however, the hood is pulled out behind it so that the sealing ring is pulled in an anticlockwise direction as seen in FIGURE 5 into and along the groove defined by the surface 55 and shoulder 53 of the boss 51. The shoulder 53 is shaped so as to form a spiral part of the groove round the pivot the wider end of the spiral part so formed being towards the right-hand end of the sealing ring as seen in FIGURE 5 and the narrower end of this spiral part being towards the left-hand side. It will be seen therefore that as the sealing ring at 54- is pulled in the anticlockwise direction as shown in FIGURE 5 it is forced into a narrower part of the groove and so is compressed to form a seal so that the high pressure air within the visor cannot leak out of the helmet round the pivot.

The right-hand side pivot illustrated in FIGURE 9 shows it with the visor in the up position and it will be seen that the part 54 of the sealing ring is not deformed whereas the view of the left-hand pivot in FIGURE 8 shows the visor in the down position and the deformation of the part 54 of the sealing ring appears quite clearly from this figure. The ends 54 and 5d of each of the sealing rings are fixed on opposite sides of the helmet to opposite ends of the plate 38 which it will be remembered seals the back of the hood against the inside of the shell. Thus when the visor is closed there is no path by way of which air may leak out of the helmet.

In order to give rapid closure of the visor when re quired it should be biased into a closed position and to effect this the side plates have an extension 57 and 57 respectively on the opposite side of the pivot to the visor. Once again a similar arrangement is provided on both sides of the helmet and the arrangement on the righthand side only will be described corresponding parts on the left-hand side being shown by primed corresponding numerals. Note however that since the visor is shown in the down position in FIGURE 8 many of the parts which will appear when in the up position as shown in FIGURE 9 will not be seen in this figure. Projecting from the extension 57 is a lug 58 formed with a hole 59 in which is fixed the end of a tension spring 60. The tension spring extends completely round the back of the helmet within the back portion of the compartment formed by the U-shaped plate 32 and it is fixed at its other end to a corresponding hole in a lug on the extension of the other side plate 46. This spring thus acts to bias the visor into its closed position.

The visor is normally prevented from closing by a locking mechanism which is provided only at the righthand side of the helmet. This mechanism includes a lever 61 pivoted at 62 and carrying at one end a roller 63. This roller is positioned adjacent the inside surface of the extension 57 and a part 64 of the extension bears on the end of the lever 61 behind the roller. In the position in which it is shown in FIGURE 10 the lever thus prevents the visor from downward movement. Provision is made for either manual or automatic closing of the visor and for manual closing there is provided an operating bar 65 extending round the outside of the shell of the helmet and pivoted concentrically with the visor about shafts 43 and 49. On the left hand side of the helmet the operating bar is merely fixed to a collar 66 which surrounds a cylinder 67 within the boss 51' and is free to rotate about this cylinder. On the right-hand side of the helmet the operating bar is fixed to a similar cylinder 68 which passes through the boss 51 and carries at its other end a plate 6% projecting below the pivot adjacent to the extension 57 of the side plate 42. One end of the plate 69 has a curved surface 70 which bears against the roller 63 on the end of the lever. When the operating bar is moved downwardly from its upper position as shown in FIGURE 1 the plate 65 is pivoted in an anti-clockwise direction as shown in FIGURE 10 and the curved surface 70 has a camming effect on the roller 63 thus pivoting the lever 61 in an anti-clockwise direction and removing the end of the lever from engagement with the part 64- of the extension 57. When this happens the restraint is removed from the visor which is then free to close under the action of the springs.

It has already been mentioned that automatic closure of the visor should take place on sudden decrease in pressure and this is preferably efiected by a barometric capsule connected by a linkage to the lever 61. The capsule 71 is housed in a compartment enclosed by a cover 72 fixed to the rigid shell 1. The cover is not airtight so that the capsule is acted on by the pressure outside the helmet. The capsule is carried on a threaded spigot 73 which is screwed into a bushing 74 formed on the end of a support plate 75 which is fixed to the casing 72. At the opposite side to the spigot 73 the capsule carries a shaft 76 termi nating in an enlarged head 77. In the position shown in FIGURES 10 and 11 this head is in contact with the end of a lever '78 pivoted at 79 to the outside of the shell 1. A11 arm 8t) is pivoted at one end 81 to the lever 78 and is pivoted at its other end 82 to a lever 83 having a collar 84 journalled to a shaft 85 which passes through the rigid shell 1. A sealing ring 86 surrounds this shaft so that pressure cannot leak out of the helmet. At its end within the rigid shell the shaft 85 has a square end 87 on which is fitted a collar 88 having two parallel projecting arms 89 and 90. A pin 91 passes between these arms and a lug 92 formed on the end of a lever shown generally as 93 is pivoted on this pin. The lever 93 is formed of two parts which are capable of moving relative to each other to change the length of the lever. One of these parts is a rod 94 on one end of which the lug 92 is formed. The other end 95 of this lever passes through a bore 96 formed in a circular plate 97 forming one end of the second part 98 of the lever and carries at its end a nut 99 which prevents the rod 94 moving completely out of the bore. A compression spring 100 bears at one end on the circular plate 97 and at its other end on an enlarged flange 101 formed round the rod 94. The part 93 of this lever is pivotally connected at 192 to a lever 103 which is pivoted about the same pivot 62 as is the lever 61. The levers 61 and 193 are riveted together at 104 so that they move together. It will be seen that the lever 61 is biased into the position already described in which its end engages the part 64 of the projection 57 by a tension spring 105 fixed at one end to the end 166 of the lever 61 and at its other end to an anchorage 107 fixed on the partition 27.

If the pressure of the air outside the helmet falls suddenly the capsule 71 will expand due to the pressure of the air within it and this will move the head 77 out of contact with the lever 78. The effect of the spring 109 acting through the linkage between the rod 94 and the lever 78 will cause this lever to rotate in a clockwise direction as seen in FIGURE and this will cause the pin 91 to be lifted as seen in this figure so that the nut 99 will contact the plate 97 with the result that the whole of the lever 93 is raised and so the levers 103 and 61 are pivoted in an anti-clockwise direct-ion. This anti-clockwise movement moves the end of the lever 61 out of engagement with the part 64 so that once again all restraint is removed from the visor and its moves to the closed position under the action of the spring 61).

Provision is also made for automatic closing of the visor on a sudden increase of pressure in the region of the wearers face such as may be caused by an explosion within the cabin or ejection from the aircraft. To produce this effect two bladders 108 and 109 are arranged in the region of the wearers temples on opposite sides of the helmet and are joined by a tube 110. A further tube 111 leads into a bellows 112 having a fixed wall formed by part of the shell 1 and a movable wall 113 joined to the fixed wall by a flexible membrane 114 and pivoted at 115. A compression spring 116 acts between the walls of the bellows to keep the movable wall 113 in contact with the end of the part 98 of the lever 93 although this spring is not strong enough to cause an anticlockwise rotation of the lever 103. The bladder 109 has an orifice 117 so that it is in communication with the air just within the helmet and is thus at the same pressure as the wearers head is at. This orifice allows changes of pressure within the bladders and bellows system in accordance with the gradual changes of pressure around the wearers face. If, however, the pressure in this region is suddenly increased the two bladders 108 and 109 will be compressed and the air within them will not be able to leak out at a sufficiently rapid rate through the orifice 117 so that it will be forced along the tube 111 into the bellows 112. The rapid increase in the volume of air within the bellows will thus pivot the movable wall 113 in an upward direction as is seen in FIGURE 10 so that the levers 1113 and 61 are moved anti-clockwise and again the end of the lever 61 is moved out of engagement with the part 64 so that the spring 60 may close the visor.

The visor is thus closed when any one of three things happen, these being manual operation by the wearer, sudden decrease in presure or sudden increase in pressure. In all these cases when it is closed, as has been described, it forms a seal with the sealing ring 16 along the ledge .15 formed within the front of the shell. The visor is firmly held against this ring to maintain the seal by the action of its operating spring 60 and it is also held down since the area of a flange 118 at the top of the visor through which the bolts 34 pass is greater than the area of the lower edge of the visor and thus there is a resultant downward force due to the pressure within the helmet. Despite these two downward forces, however, it would still be possible for the visor to open, if say, it received a blow of any sort. It is therefore preferable 8 to lock the visor in its closed position and this is done by means of the lock shown in detail in FIGURE 13. Two of these locks 119 and 120 are provided, one at each side of the helmet but only one of them will be described in detail.

Each lock comprises a hook 121 pivoted at one end 122 to the outside of the rigid shell 1 and having an end which can engage a recess 123 formed in the outer sheet 11 of the visor. The hook is biased by a spring 124 to a position in which it is just clear of the downward rate of the visor. The action of the spring 60 on closure of the visor means that it reaches its closed position before the operating bar 65 reaches its lowest position so that the recess 123 is in position before the operating bar descends and hitting the outer surface of the hook 121 forces it into engagement with the recess to hold the visor firmly locked in its downward position. On movement of the bar 65 upwards the hook springs out of the recess to its normal position.

Since the lock is dependent on the operating bar being in its downward position it is necessary to ensure that the operating bar does descend whether the visor is closed manually or automatically. Referring to FIGURE 10 it will be seen that a linkage is provided between the extension 57 of the side plate 42 and the plate 69 such that on anticlockwise rotation of the side plate, i.e. on closing of the visor, the plate 69 is also rotated anti-clockwise. For this purpose the side plate 42 has a projection 127 which engages a hole 126 in the plate 69. It will thus be seen that as the visor descends the plate 69 is forced to rotate in an anti-clockwise direction with the side plate 42 so the operating bar will descend. It is necessary for movement of the bar to continue after the visor has stopped so it can operate the lock and to achieve this a single coiled wire spring 125 surrounds the part of the plate 69 which encircles the cylinder 68 and is fixed at one end in the hole 59 formed in the lug 58 of the side plate 42. At its other end the spring 125 passes through the hole 126 in the plate 69 so that after the visor has closed the spring 125 will move the plate 69 and thus the operating bar through an extra angle, determined by the width of the hole 126 so that the bar 65 hits the hook 121.

After the visor has closed it will be seen that the spring 165 will return the levers 6'1 and 103 into their original positions as shown in FIGURE 10. All the parts of the linkage between lever 103 and lever 78 also retain their normal positions and the lever 78 is in such a position that the capsule may contract and the head 77 move back to hold the lever 78 in its original position. The whole of the operating mechanism is thus reset while the visor is closed so that when it is opened the end of the lever will again be in contact with the part 64 to hold the visor in the open position. The visor is opened by a manual upward movement of the operating bar 65 and it will be seen that the hole 126 allows a certain amount of lost motion so that the operating bar is moved out of contact with the hook 121 thus opening the lock before upward movement of the visor is commenced. The upward movement of the bar is transmitted to the visor once again by the part 127 projecting into the hole 126.

The visor 10 is made of clear material and when flying in very sunny conditions it is necessary for the wearer .to have a sun visor over his eyes to stop excessive glare. This visor is best shown in FIGURE 3 and is indicated by the reference numeral 128. It is also substantially luneshaped when seen in transverse section and is pivoted at each side of the helment around sleeves 129 and 129 respectively. It is shaped at the front as shown in FIG- URE 2 so that there is no interference with the oxygen mask. The visor is thus free to move about the same axis as the visor so that when the visor is in the closed position the sun visor can also be moved to a lower position within the visor. The position of the sun visor is a lever 130 which is shown in more detail in FIGURES 6 and 8. It will be seen from FIGURE 8 that the lever is journalled at the opposite end of the sleeve 129' to the end on which the sun visor is fixed and that it is positioned outside the shell 1 of the helmet. The lever is able to move between the two positions shown in FIG- URE 6 and the sun visor is in the raised position as shown in FIGURE 2 when the lever is in the position shown in broken lines in FIGURE 6 and is in the lowered position when the lever is in the position shown in full lines in FIGURE 6. The lever 130 has an integral plate 131 substantially segmental in shape. This plate is formed with an arcuate hole 162. Cooperating with this hole is a pin 133, shown in FIGURE 6 only, projecting from the shell of the helmet. It will be seen from FIGURE 6 therefore that the limits of travel of the lever 130 in either direction of rotation are defined so that the sun visor cannot be moved to a position more clockwise of that shown in FIGURE 3 and cannot be lowered to a position beyond which this leading edge 134 is in the position shown in broken lines in FIGURES 2 and 3. It will be noticed that this position is not low enough to foul the oxygen mask and yet is low enough to provide etfecti-ve shielding of the wearers eyes. Along its lower outer edge the sun visor carries a pad 135 which is in contact with the inside of the inner sheet 12 of the visor so that as the sun visor is raised and lowered the inside of the visor is wiped so that any condensation which may have formed is removed.

It will be noticed that hand wheels 136 and 136' are provided one at each side of the helmet and that these are mounted directly on the ends of the pivot pins 48 and 49. These hand Wheels carry a plate 137 having a toothed edge 136 which cooperates with a gear 139. The gear is journalled at one end to a shaft 140 which passes through the outer shell and armies at its inner end a capstan 141. A sealing ring 142 surrounds the shaft where it passes through the shell so as to prevent leakage of the air from within the helmet. Corresponding parts on the left-hand side of the helmet are again shown by primed reference numerals. A cord 143 is wound on the capstan 141 and a similar cord 144 on capstan 141'. These cords are connected so that on rotation of the hand Wheel 136 the oxygen mask and ear-buns 145 are pulled inwards towards the centre of the helmet to a close fit against the wearers face. The cord 144 is similarly connected to bring a pad for bearing against the back of the wearers head and two pads for bearing against the wearers temples neither of which are shown in detail in the drawings, into position against the wearers head. This assembly is described and claimed in more detail in co-pending application No. 9,315 61 and since it forms no part of the present invention will not be described in any more detail.

It will be seen from FIGURE 9 that the pin 48 forms a common axis about which a number of members are able to rotate. These are the wheel 136 which is journaled on to it directly, the sun visor 128 which is journalled on to it by means of sleeve 129, the operating bar 65 journal-led on to it by means of sleeve 68 and the side plate 42 of the visor 10. The outermost of these sleeves, 68 is, as has already been explained surrounded by the part 51 of the rigid shell 1. To prevent leakage of high pressure air from within the helmet a sealing ring 146 is held between the part 51 and the sleeve 68 and a further sealing ring 147 is held between the sleeve 68 and the sleeve 129. It is understood that similar sealing rings 146' and 147 are provided between corresponding parts of the body at the left-hand side of the helmet.

It will be noticed in FIGURE 3 that the compartment 28 ends at a position approximately half way down the back of the rigid shell. In order to keep the inner outline of the helmet smooth, padding 148 is fixed Within the rigid shell and a thinner extension of this padding 149 extends within the compartment and terminates in an enlarged portion 150 surrounding the front edge of the compartment. Within the back part of the padding there is a chamber 151 in which is mounted the earphone (not shown) of the wearers radio. The chamber leads by an acoustic tube 152% the ear-bun and a similar acoustic tube leads to the ear-bun on the other side of the helmet.

I claim:

1. A flying helmet for use with a pressurised fiying suit, said helmet comprising: a rigid shell for fitting over a waerers head, said shell being formed with an open front part; a substantially lune-shaped visor; means pivotally mounting said visor within said helmet so that it can move between an open position where it is stored within said shell and -a closed posit-ion where it covers said open front part; sealing means carried by the lower edge of said visor; a sealing ledge supported within and by said shell below said open front part and arranged so that said sealing means on the lower edge of said visor makes sealing contact with said sealing ledge when said visor is in said closed position; a hood of flexible foldable pressure-tight material, means including a deformable seal sealing said hood to the upper edge of said visor, around said means pivotally mounting said visor, and to the inside of said shell in such .a Way that when said visor is in said open position said hood is folded behind it within said shell and when said visor is in said closed position said hood is opened and consttutes a pressure-tight connection between said upper edge of said visor and said hood.

2. A flying helmet as claimed in claim 1, wherein said hood is shaped substantially as a lune with the points cut off at each end in such a way that said ends of said lune are concave, said hood including a sealing rim at each end defining the concave ends, and wherein said means pivotally mounting said visor includes at each side a member at least partly surrounding said means, said member being formed with a groove in which is seated said sealing rim, said rim and groove cooperating to form a pressure-tight sea 3. A flying helmet as claimed in claim 2, wherein the groove in said member narrows toward one end, and said sealing rim extends along the side of said visor from the point where said hood joins said visor whereby when said visor is closed said rim is forced along the groove towards the narrow end and is thus compressed to form said pressure-tight seal.

4. A flying helmet as claimed in claim 1 and including a substantially lune-shaped partition fixed within the top of said shell to form an open-fronted compartment in which said visor is stored when in said open position, and in which said hood is stored.

5. A flying helmet as claimed in claim 1, wherein said means pivotally mounting said visor include at each side of said helmet a side plate to which said visor is fixed; a pin pivotally mounting said side plate, and an extension of said side plate projecting beyond the axis of said pin on the opposite side of the axis .to said visor, and wherein said helmet includes a tension spring fixed .at its first end to said extension from said side plate at one side of said helmet, extending round the back of said helmet within said shell and supported on the inner periphery of said shell, and fixed at its second end to said extension from said side plate at the other side of said helmet, said spring thus biasing said visor to said closed position.

6. A flying helmet as claimed in claim *5 and including: at one side of said helmet only, a lever associated with said side plate at that side of said helmet; and means mounting said lever for movement between a first position in which it bears on said side plate to lock said visor in an open position, and a second position in which it is out of contact with said side plate and allows said visor to close under the action of said spring.

7. A flying helmet as claimed in claim 6 and including: an operating bar, extending around the outside of said shell and movable between an upper position above the opening and a lower position below the opening; a sleeve surrounding said pin at said one side of said helmet; first journal means connecting one end of said operating bar to a first end of said sleeve; a plate adjacent to said extension of said side plate; second journal means connecting said plate to a second end of said sleeve; and a cam surface on said plate, said cam surface being in contact with said lever and being shaped so that when said operating bar is moved downwardly from said upper posit-ion said cam surface moves said lever out of contact with said side plate to allow said visor to close.

8. A flying helmet as claimed in claim 6 and including: a barometric capsule; and a linkage connecting said capsule to said lever, said linkage being such that when the pressure outside said helmet drops to a certain value said lever is moved out of cont-act with said side plate thus allowing the visor to close automatically.

9. A flying helmet as claimed in claim 6 and including: a bladder positioned at the front of said helmet; an expandable bellows having one fiXed and one movable wall; and a tube connecting said bladder to said bellows, said mov- References Cited by the Examiner UNITED STATES PATENTS 3,050,735 8/1962 Newman et al. 26

FOREIGN PATENTS 815,498 6/1959 Great Britain. 815,499 6/1959 Great Britain.

JORDAN FRANKLIN, Primary Examiner.

DAVID J. WILLIAMOWSKY, Examiner.

Claims (1)

1. A FLYING HELMET FOR USE WITH A PRESSURISED FLYING SUIT, SAID HELMET COMPRISING: A RIGID SHELL FOR FITTING OVER A WAERER''S HEAD, SAID SHELL BEING FORMED WITH AN OPEN FRONT PART; A SUBSTANTIALLY LUNE-SHAPED VISOR; MEANS PIVOTALLY MOUNTING SAID VISOR WITHIN SAID HELMET SO THAT IT CAN MOVE BETWEEN AN OPEN POSITION WHERE IT IS STORED WITHIN SAID SHELL AND A CLOSED POSITION WHERE IT COVERS SAID OPEN FRONT PART; SEALING MEANS CARRIED BY THE LOWER EDGE OF SAID VISOR; A SEALING LEDGE SUPPORTED WITHIN AND BY SAID SHELL BELOW SAID OPEN FRONT PART AND ARRANGED SO THAT SAID SEALING MEANS ON THE LOWER EDGE OF SAID VISOR MAKES SEALING CONTACT WITH SAID SEALING LEDGE WHEN SAID VISOR IS IN SAID CLOSED POSITION; A HOOD OF FLEXIBLE FOLDABLE PRESSURE-TIGHT MATERIAL, MEANS INCLUDING A DEFORMABLE SEAL SEALING SAID HOOD TO THE UPPER EDGE OF SAID VISOR, AROUND SAID MEANS PIVOTALLY MOUNTING SAID VISOR, AND TO THE INSIDE OF SAID SHELL IN SUCH A WAY THAT WHEN SAID VISOR IS IN SAID OPEN POSITION AND HOOD IS FOLDED BEHIND IT WITHIN SAID SHELL AND WHEN SAID VISOR IS IN SAID CLOSED POSITION SAID HOOD IS

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