GB1584269A

GB1584269A - Ejector seats

Info

Publication number: GB1584269A
Application number: GB13925/77A
Authority: GB
Original assignee: UK Secretary of State for Defence
Current assignee: UK Secretary of State for Defence
Priority date: 1977-04-01
Filing date: 1977-04-01
Publication date: 1981-02-11
Also published as: SE7803657L; DE2813893A1; FR2385586A1

Description

(54) IMPROVEMENTS IN OR RELATING TO EJECTOR SEATS (71) 1, SECRETARY OF STATE FOR DEFENCE, LONDON, do hereby declare this invention, for which I pray that a patent be granted to me and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention relates to ejector seats for ejecting personnel from cockpits of vehicles and craft particularly aircraft. It is concerned with means for restraining the arms of such personnel during an ejection sequence so as to prevent injury thereto which might otherwise arise upon their sudden exposure to air at a high relative velocity.

In co-pending UK Patent Application 48260/75 there is described an arm restraint apparatus for restraining the arms of ejecting personnel, the apparatus comprising two nets attached and normally stowed one each side of an ejector seat and means for deploying the nets at commencement of the ejection, the deploying means including net casting means operable to cast a side of the nets laterally outwards, whereby in the course of an ejection sequence the nets encompass the user's elbows and are then drawn in toward the seat to restrain the user's arms and prevent them from being deleteriously affected by external air blast.

The present invention is an improvement in or modification of that described in copending UK Patent Application 48260/75 (Serial No. 1 570 283).

According to the present invention an ejector seat has arm restraint apparatus for restraining an arm of ejecting personnel and comprising a net attached to a side of the ejector seat and detachably held in an outspread configuration substantially laterally outwards from the seat, and net deployment means operable to detach the net from its outspread configuration and draw it around an elbow and arm of a user.

When used in a cockpit, the outspread configuration of the net may be obtained by detachable attachment, at least of a part of the net remote from the seat, to the cockpit side or rear walls. Alternatively the detachable attachment may be to other structure in the cockpit or to outriders on the seat itself, a possibility in the latter case being that outriders may be used in stabilising the seat in free flight.

The net deployment means preferably includes a line, which might be a cord or tape attached to a part of the net remote from the seat and so associated with the seat and line drawing means as in use to detach the net from the said detachable attachment and draw the said remote part of the net forward and toward the seat, whereby when used with a person in the seat an arm of the person will be caught by the net and restrained against his body and/or the seat.

The line may be associated with the seat, perhaps via fair-leads attached to the seat, preferably well forward on a side thereof and at about lap or knee level. The line may be stowed under a protective cover from which it can readily be extracted on operation of the deployment means. The protective cover may comprise flexible plastics or a rubber tube with a longitudinal slit therealong or fabric flaps closed by touch and close fasteners, or frangible adhesive tape.

A typical route for the line includes the side of the seat and lower hem of the net. The line may be attached to the lower hem of the net with frangible adhesive tape. Alternatively a possibly safer line stowage route for the avoldance of entrapment of the user's fingers may be directly outwards from the front of the seat and along the cockpit wall.

In the context of the present patent specification the word "net" indicates function rather than construction of the arm restraint means. Nevertheless a reticulated fabric is preferred to any other fabric for lightness and relative insensitivity to blast.

The net may be substantially triangular in shape, with one side attached to the back of the seat and the opposite apex constituting the part of the net remote from that attached to the seat and which is detachably attached so that the net is held in the said outspread configuration. The side attached to the seat preferably extends from a headrest region of the seat down to the seat por tion thereof so that each net can provide protection and restraint for a user's shoulders as well as the whole arm. The net may be concave, that is shaped like a hammock or sling. Alternatively a bag effect can be obtained by providing that operation of the deployment means bunches up part of the net remote from that attached to the seat.

Where a reticulated fabric is used, the net may have a mesh size, at least in a region thereof remote from that attached to seat, small enough not to permit the user's fingers to pass therethrough and entangle in the net. In the region of attachment to the seat the net may have a larger mesh, but this should not be so large as to permit the intrusion therethrough by, or entrapment thereby of, a user's elbow.

Advantageously the deployed net extends from the back of the seat to as far forward thereof as possible. Insofar as this distance is larger than that between the back of the seat and the as stowed anchorage of an outer part of the net, a lower or both a lower and an upper, or all three sides of the net may be pre-tensioned with elastic cords so as to prevent the net from flopping about while in the stowed configuration.

Motivation for the deployment means is likely to be provided in one of or a combination of two ways.

One way employs a distinct restraint means deployment motor, which may also be used for deploying leg restraint means.

The other way employs ejection of the seat.

In the said one way, deployment motors may be mounted on the side of or beneath the seat to reel in the line, and much if not all of the deployment of the net can be accomplished before the seat begins to leave the cockpit. The motors may be so mounted that fairleads are not required, although these will probably be used in practise to control the feed of line to the motors.

In the said other way the line may pass via a snubber block, and thence to the floor of the cockpit, there being also release means for releasing the connection thereby formed by the line between the snubber clock and the cockpit floor. The release means may be Provided in a frangible anchorage to the floor of the cockpit, in the line being frangible at a point which will in the deployed configuration of the net be downstream of the snubber, or in cutter means provided to cut the lines down-stream of the snubbers.

In an alternative route the line may pass around a pulley attached to a cockpit datum and thence to an anchorage on the seat. In this alternative the pulley or seat anchorages or the line may be frangible.

Detachable attachment of the net in an outspread configuration may be obtained using press studs or touch and close fasteners, for example Velcro (registered trademark) fasteners. Advantageously it includes a slide or like means which enable the part of the net remote from the seat to be drawn forwards a certain amount following detachment, before being drawn toward the seat.

Where the arm restraint apparatus is arranged for deployment by the said one way, slide means associated with the detachable attachment may have a substantially horizontal forward alignment, possibly curving upward at the forward end if seat ejection is to have commenced before nets deployment is complete. Where the apparatus is arranged for deployment by the said other way, such slide means may be in a substantially vertical alignment, any horizontal component, or element if the slide is curved, being only such as will be required by virtue of the trajectory of the seat (which generally has a rearward component).

It is sometimes the case with aircraft having a two man crew that one can commence the ejection sequence of the other. It may then be advantageous to employ a different arm restraint apparatus as between the two situations. In a navigator's "command ejection" situation cord/suit arm restraint apparatus such as those described in UK Patent Specifications 1008476 or 1481791 may be preferred. Indeed net apparatus of the type described in co-pending K Patent Application 48260/75 (Serial No. 1570283) may be preferred in one of the above situations, or the said one way of deploying the apparatus of the present invention may be preferred in one situation and the said other in the other. Moreover different arm restraint means may be employed as between one user's two arms, although it will be preferred that if possible both arms be restrained similarly.

If a facility of seat and height adjustment requires adjustment to the line or anchorages of arm restraint apparatus according to the present invention, this may be accomplished using inertia devices, preferably those of the type which lock the cord upon sensing a given line acceleration as distinct from vehicle acceleration.

As with the net apparatus described in co-pending UK Patent Application 48260/75 (Serial No. 1570283) the present net apparatus can readily be arranged to permit the user sufficient freedom to operate emergency oxygen supplies, manual seat/man release, or to adjust his person.

The arm restraint apparatus of the present invention may include restraint release means, preferably automatic with manual override. These may comprise means for jettisoning the net, for releasing shoulder end and/or forward anchorages, and/or manual loosening means. Where snubbers are employed a snubber override may be fitted thereon to provide manual loosening or release of either net.

Two embodiments of the present invention will now be described by way of example with reference to the drawings accompanying the Provisional Specification, of which: Figure 1 is a side view of an ejector seat according to the first embodiment with an arm restraint net in a stowed configuration, Figure 2 is a front view of the seat illustrated in Figure 1, Figure 3 is a side view of the seat illustrated in Figure 1 but with the arm restraint net deployed, Figure 4 is a side view of an ejector seat according to the second embodiment with an arm restraint net in a stowed configuration, and Figure 5 is a side view of a seat as in Figure 4 but with the net in a deployed configuration.

The aircraft ejector seat illustrated in Figures 1 to 5 includes a seat member 10 and a headrest 11. The seat member 10 has a seat back 10a, a seat portion 10b, a footrest portion 10c, and an ejection handle 10d, and is adjustable in height with respect to the headrest 11. On a side of the seat portion 10b is located a manual seat/man release control 12. An arm restraint net 13 is anchored to the seat back 10a. The net 13 is substantially triangular. It has for a lower, forward part a mesh size of about 1 cm side and for the upper rearward remainder a mesh size of 5 cms side. As the cockpit wall is not as far from the seat back as the seat front the two free sides 13a, b, of the net comprise tape pretensioned with elastic cords so that the net is unable to flop about unwantedly while in a stowed configuration.

A slider 14 attached to a free apex of the net is used to attach detachably the net to the cockpit of the aircraft. A deployment cord stowage tube 15, comprising a slit tube of plastics material, extends on the side of the seat from the lower anchorage of the net to a fairlead 16 located well forward on the net side. The upper apex of the net 13 is linked via a tapewitha inertia reel 18 near the top of the headrest 11. The inertia reel 18 is of the type which locks on sensing a predetermined tape acceleration with respect thereto, and is arranged to release the tape 17 during operation of the seat/man release.

The seat/man release is arranged to withdraw the net anchorage and fastening entirely and allow the net to fall away from the seat and the user. The upper apex of the net is arranged to lie just outside the reel 18 in the highest seat position. The seat has lap, body and shoulder straps 19a, b, c.

In the first embodiment of the invention, illustrated in Figures 1 to 3 the net deployment means includes a tape 20, a snubber 21 attached to the seat side below the fairlead 16, a pulley bar 22 attached to the floor of the cockpit, and an inertia reel 23 attached to the bottom of the seat. The tape 20 thus extends, in the stowed configuration, from the inertia reel 23, around the pulley bar 22, through the snubber 21 and fairlead 16, and along the interior of the tube 15 and the hem 13a of the net, to the free apex of the net. The tape 20 is attached to the hem 13a with frangible adhesive tape.

The tape 20 is frangible at a position which when the net is deployed will be not more than about 10 cms below the snubber to prevent snagging. The snubber has an override button 21a, operation of which will permit the tape 20 to be pulled back through the snubber.

The inertia reel 23 is similar in operation to the inertia reel 18. The reels 18 and 23 are employed to cater for height adjustment of the seat 10 with respect to the headrest 11.

A runner 26 is attached to a cockpit wall 27, tilted slightly forward from the vertical.

It slidably accommodates the slider 14. Its upper end is open to allow the slider 14 to run out thereof. The length and configuration of the runner 20 are such that at the low adjustment position of the seat 10 the slider will just run out of the runner when the tape 20 is taut.

As a fail-safe measure the connection of the pulley bar 22 to the floor is also frangible.

A description of the mode of operation of the first embodiment now follows. Upon entry to the cockpit an aircrewman will check and if necessary adjust the height of the seat portion 10 and the tapes 20 and 17 will be paid out or reeled in by the inertia reels 18, 23, as required. He attaches his harness using the straps 19, a, b, c.

If he requires to eject he pulls the handle 10d. The motion of the seat brings about tensioning of the tape 20 locking the reels 18 and 23 and breaking the tape 20 out of the tube 15 and the adhesive tape on the hem 13a. During this time the slider 14 has passed some way up the runner 26 bringing the free apex of the net forward with respect to the seat. When the slider 14 runs out of the runner the free apex of the net is pulled by the tape 20 toward the fairlead 16. When the net hems 13a and b are taut the tape 20 breaks below the snubber block.

On automatic seat/man separation facility operation the straps 19a, b, c are freed at their seat end, the tapes 17 and 20 are freed from the reels 18 and 23, and the net anchorage, from the seat. In the event of failure of this facility, the aircrewman can release himself using the control 12 and the override button 21a.

In the second embodiment of the inven tion, illustrated in Figures 4 and 5, the net deployment means includes a tape 30, a motorised reel 31, and a runner 32.

The tape 30 extends from the reel 31 through the fairlead 16 and the tube 15, and along the hem 13a on the net to its free apex. The tape 30 is attached to the hem 13a with a frangible adhesive tape. The reel 31 is associated with the seat/man release means so that operation of the latter frees the tape 30 from the reel.

The runner 32 is attached to the cockpit wall in an horizontal configuration longitudinally of the cockpit. It slidably accommodates the slider 14. Its forward end is open to allow the slider 14 to run out thereof.

Upon entry to the cockpit an aircrewman will carry out the procedures described above with respect to the first embodiment.

The elastic pretensioning of the hems 13a, b, is arranged to cater for variation in their lengths due to height adjustment.

When the ejection handle l0d is pulled operation of the motorised reels 31 commences and the tape 30 breaks out of the tube 15 and the adhesive tape. While it is substantially normal to the runner 32 the slider 14 does not move, but once taut from the slider 14 to the fairlead 16 the tape pulls the slider forward and out of the runner.

The free apex of the net is then pulled toward the fairlead 16 and the inertia reel 18 locks. Thus deployment of the net is arranged to be substantially complete before the seat begins to leave the aircraft.

Upon operation of the seat/man separation facility the tapes 17 and 30 and the net anchorage are freed from the reels 18, 31 and the seat respectively.

It will be appreciated that the net and leg restraint apparatuses described above and illustrated in the drawings are substantially similar on both sides of the seat. They need not be, however, and in circumstances where the disposition of equipment on the seat and in the cockpit demands it, one side may have a net in accordance with the present invention and the other one according to the invention described in UK Patent Specification 48260/75 (Serial No.

1 570 283) or a net which has no means to cast it outwards or even some other arm restraint apparatus.

The above embodiments are described, of course, by way of example only, and undoubtedly the embodiments of the invention will occur to those skilled in the art. For example it may be desirable in certain cockpit configurations for the net at least on one side of the seat to be reeled in from the headrest anchorage rather than the seat anchorage and, in such cases the net may be permanently attached to both the seat portion side and back rest and the deployment of the net arranged to gather up a free side thereof.

WHAT I CLAIM IS: 1. An ejector seat having an arm restraint apparatus for restraining an arm of ejecting personnel, the apparatus comprising a net attached to a side of the ejector seat and detachably held in an outspread configuration substantially laterally outwards from the seat, and net deployment means operable to detach the net from its outspread configuration and draw it around an elbow and arm of a user.

2. An ejector seat as claimed in claim 1 and wherein the outspread configuration is obtained by detachable attachment, at least of a part of the net remote from the seat, to the cockpit side or rear walls.

3. An ejector seat as claimed in claim 1 and wherein the outspread configuration is obtained in detachable attachment of at least a part of the net remote from the seat to outriders on the seat.

4. An ejector seat as claimed in any one of claims 1 to 3 and wherein the net deployment means includes a line attached to a part of the net remote from the seat and so associated with the seat and line drawing means as in use to detach the net from the said detachable attachment and draw the said remote part of the net forward and toward the seat, whereby when used with a person in the seat an arm of the person will be caught by the net and restrained against his body and/or the seat.

5. An ejector seat as claimed in claim 4 and having a protective cover for stowing the line.

6. An ejector seat as claimed in claim 5 and wherein the protective cover comprises a slit rubber tube.

7. An ejector seat as claimed in any one of the preceding claims and wherein the deployment means includes a seat mounted deployment motor.

8. An ejector seat as claimed in any one of claims 1 to 6 and wherein net deployment is motivated by the ejection of the seat.

9. An ejector seat as claimed in claim 8 and wherein the line passes via a snubber block, and thence to the floor of the cockpit, there being also release means for releasing the connection thereby formed by the line between the snubber block and the cockpit floor.

10. An ejector seat as claimed in claim 9 and wherein the release means is provided in a frangible anchorage to the floor of the cockpit.

11. An ejector seat as claimed in claim 9 and wherein the release means is provided in the line being frangible at a point which will in the deployed configuration of the net be down-stream of the snubber.

12. An ejector seat as claimed in claim 9 and wherein the release means is provided

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. tion, illustrated in Figures 4 and 5, the net deployment means includes a tape 30, a motorised reel 31, and a runner 32. The tape 30 extends from the reel 31 through the fairlead 16 and the tube 15, and along the hem 13a on the net to its free apex. The tape 30 is attached to the hem 13a with a frangible adhesive tape. The reel 31 is associated with the seat/man release means so that operation of the latter frees the tape 30 from the reel. The runner 32 is attached to the cockpit wall in an horizontal configuration longitudinally of the cockpit. It slidably accommodates the slider 14. Its forward end is open to allow the slider 14 to run out thereof. Upon entry to the cockpit an aircrewman will carry out the procedures described above with respect to the first embodiment. The elastic pretensioning of the hems 13a, b, is arranged to cater for variation in their lengths due to height adjustment. When the ejection handle l0d is pulled operation of the motorised reels 31 commences and the tape 30 breaks out of the tube 15 and the adhesive tape. While it is substantially normal to the runner 32 the slider 14 does not move, but once taut from the slider 14 to the fairlead 16 the tape pulls the slider forward and out of the runner. The free apex of the net is then pulled toward the fairlead 16 and the inertia reel 18 locks. Thus deployment of the net is arranged to be substantially complete before the seat begins to leave the aircraft. Upon operation of the seat/man separation facility the tapes 17 and 30 and the net anchorage are freed from the reels 18, 31 and the seat respectively. It will be appreciated that the net and leg restraint apparatuses described above and illustrated in the drawings are substantially similar on both sides of the seat. They need not be, however, and in circumstances where the disposition of equipment on the seat and in the cockpit demands it, one side may have a net in accordance with the present invention and the other one according to the invention described in UK Patent Specification 48260/75 (Serial No.

in cutter means provided to cut the lines down-stream of the snubbers.

13. An ejector seat as claimed in claim 8 and wherein the line passes around a pulley attached to a cockpit datum and thence to an anchorage on the seat, the pulley or seat anchorages or the line down-stream of the snubber being frangible.

14. An ejector seat as claimed in any one of the preceding claims and wherein an arrangement detachably holding the net in an outspread configuration includes a slide/runner combination enabling in use the part of the net remote from the seat to be drawn forward with respect to the seat prior to being drawn toward the seat.

15. An ejector seat as claimed in claim 7 and wherein an arrangment detachably holding the net in an outspread configuration includes a slide/runner combination enabling in use the part of the net remote from the seat to be drawn forward with respect to the seat prior to being drawn toward the seat, the slide/runner combination being aligned substantially horizontally with respect to the seat.

16. An ejector seat as claimed in claim 15 and wherein towards its forward end the slide/runner combination curves upward.

17. An ejector seat as claimed in any one of claims 8 to 13 and wherein an arrangement detachably holding the net in an outspread configuration includes a slide/runner combination enabling in use the part of the net remote from the seat to be drawn forward with respect to the seat prior to being drawn toward the seat, the slide/runner combination being aligned substantially vertically.

18. An ejector seat as claimed in any one of the preceding claims and wherein the net is substantially triangular in shape, with one side attached to the back of the seat and the opposite apex constituting the part of the net remote from that attached to the seat and which is detachably attached so that the net is held in the said outspread configuration.

19. An ejector seat as claimed in claim 18 and wherein the side of the net attached to the seat extends from a headrest region of the seat down to the seat portion thereof so that each net can provide protection and restraint for a user's shoulders as well as the whole arm.

20. An ejector seat as claimed in any one of the preceding claims and wherein the net is concave.

21. An ejector seat as claimed in any one of the preceding claims and wherein the net is reticulated with a mesh size, at least in a region thereof remote from that attached to seat, small enough not to permit the user's fingers to pass therethrough and entangle in the net.

22. An ejector seat as claimed in claim 21 and wherein in the region of attachment to the seat the net has a larger mesh but not so large as to permit the intrusion therethrough by, or entrapment thereby of, a user's elbow.

23. An ejector seat as claimed in any one of the preceding claims and wherein at least one side of the net is pre-tensioned with elastic material.

24. An ejector seat as claimed in any one of the preceding claims and having an inertia device permitting adjustment of seat height with respect to net anchorage.

25. An ejector seat as claimed in any one of the preceding claims and having automatic restraint release means for jettisoning the net, for releasing shoulder end and/or forward anchorages, and/or manual loosening means.

26. An ejector seat as claimed in claim 25 and wherein the restraint release means has a manual override.

27. An ejector seat as claimed in any one of the preceding claims and substantially as hereinbefore described with reference to Figures 1 to 3 of the drawings accompanying the Provisional Specification.

28. An ejector seat as claimed in any one of claims 1 to 26 and substantially as hereinbefore described with reference to Figures 4 and 5 of the drawings accompanying the Provisional Specification.