Aircrew headgear ejection means

An apparatus for ejecting an aircrewmans helmet-mounted electro-optical equipment from an aircraft cockpit comprising an arm having a first end pivotally mounted at a position behind an aircrewmans ejection seat, a second end of the arm having on it a line reel-in apparatus and a flexible line depending therefrom, the flexible line attachable to helmet mounted electro-optical equipment, a guide and damper connecting the arm to the ejection seat, upon operation of the ejection seat the electro-optical equipment being detached from the helmet, the ejection seat rising in the cockpit and causing rotation of the arm about the pivot point, the line reel-in apparatus locking to prevent the line extending and the electro-optical equipemnt being ejected from the cockpit into the airstream by rotation of the arm prior to the ejection seat leaving the cockpit.

The present invention relates to aircrew headgear. It is particularly 
concerned with equipment such as optical equipment mounted on a protective 
helmet and the detachment thereof from the helmet upon operation of an 
ejection seat. 
When optical equipment, for example, is mounted on aircrew protective 
headgear, it is usually to the fore thereof. If it were to remain attached 
to the protective helmet during ejection of the aircrew from an aircraft 
loads are likely to be imposed upon the aircrewman which could be 
unacceptable or at worst fatal. However it is also important for the 
equipment not to be jettisoned so freely that a risk arises of injury to 
the aircrewman or any colleague and that their vital equipment is not 
damaged. 
The present invention provides means for controlled jettisoning of the 
equipment from the cockpit whilst restraining the equipment after 
detachment from the headgear so as to minimise the risk of injury or 
damage to essential personal equipment. 
By means of the present invention, any helmet-mounted equipment can be 
automatically and rapidly removed by the operation of the ejection seat 
and this invention accordingly consists of apparatus for ejection of 
aircrew helmet-mounted equipment from an aircraft cockpit, comprising an 
ejector arm engageable wih an airman's ejection seat and having a first 
end pivotally mountable behind the seat, and a flexible linkage for 
attching the helmet-mounted equipment to the second end of the ejector 
arm, so that in operation of the ejection seat, the arm is rotated about 
its pivot by upward movement of the ejection seat so that the equipment is 
detached from the airman's helmet and ejected from the cockpit by the 
rotating arm. 
According to a second aspect of the present invention the ejector arm is 
mounted in the cokpit and offset to the centre line of the aircrewmans 
seat. 
Advantageously the ejector arm is offset to one side of the seat and 
arranged to cross the head of the seat so that upon rotation of the arm, 
an arc is described which provides a trajectory which will jettison the 
equipment to one side of the aircraft, so that its path is not coincident 
with that of the escaping crew member. 
According to a further aspect of the present invention the ejector arm is 
provided at its free end with an inertia reel-in device adapted to receive 
the line connecting the helmet-mounted equipment when the line is not 
under tension and to lock and prevent the line feeding out under 
conditions of high loading. 
The inertia reel-in device may be conveniently provided to prevent the line 
connecting the ejector arm to the optical equipment from becoming 
excessively long with a consequent risk of entanglement and yet still 
allow the aircrewman a considerable amount of freedom of helmet movement. 
According to a further aspect of the present invention the second end of 
the ejector arm is provided with a telescopic portion located coaxially 
with the end of the ejector arm, the telescopic portion being connectable 
at its free end to an inertia reel-in assembly, and the telescopic portion 
being extendable on ejection. 
The telescopic portion of the ejector arm is advantageous in that the arm 
in its shorter length does not unduly restrict movement of the aircrewman 
and when extended on ejection it will take the jettisoned equipment clear 
of the aircrewman in a forward direction prior to its ejection from the 
cockpit. 
According to a further aspect of the present invention there is provided an 
ejector arm having a hinge point along its length, to facilitate access to 
the cockpit for the entering or exiting crewman. 
The hinge is arranged to hinge upwardly or sideways but in such manner that 
in the event of an emergency evacuation the arm would remain straight.

FIGS. 1 and 2 show an aircrewman seated in an aircraft cockpit with the 
cockpit canopy 10 in the closed position. The aircrewman is wearing a 
protective helmet 11 and oronasal mask 12, and in front of his eyes is a 
piece of helmet-mounted optical equipment 13, detachably connected to the 
helmet by clip assembly 13a. The aircrewman is seated in an ejection seat, 
of which only the head box 14 is shown. An ejector arm 15 is pivotally 
mounted to the airframe at a point behind the ejection seat. The pivot 16 
is mounted so that its axis is inclined with respect to the roll and pitch 
axes of the aircraft. The ejector arm depends from the pivot point and 
passes over the top of the head box 14 of the ejector seat to terminate at 
a positin above the aircrewmans head. The under surface of the ejection 
arm 15 is acted upon by a roller 17 mounted on the head box of the 
ejection seat. The arm is also supported by a damper assembly 18 to hold 
the arm in place and minimize movements caused by vibrations. The arm is 
hinged near its midpoint. The hinge 19 is arranged to allow rotation of 
the arm in either an upward and/or outward direction to permit improved 
access to the cockpit. At its free end the arm has a telescopic segment 
20, located coaxially with the ejection arm 15. The free end of the 
telescopic segment carries an inertia reel-in assembly 21. The optical 
equipment mounting bracket 13a is attached by a line 22 to the inertia 
reel-in assembly 21. If the helmet-mounted equipment is some form of 
electro-optical equipment, electrical and/or optical cables may feed power 
or data to and from the bracket 13a to the reel-in device 21. The ejector 
arm 15 is contoured so as to pass as closely as possible to the cockpit 
canopy 10 thereby enabling the pilot to sit high in the cockpit. 
In routine operation the helmet-mounted equipment 13 will be attached to 
the inertia reel-in device 21 by line 22. The device permits the 
aircrewman to move his head freely whilst the helmet-mounted equipment is 
retained by a line 22 connected to the inertia reel-in device. In the 
event of any particularly strong inertial forces being encountered the 
device will lock and prevent the line paying out any further. Normally the 
telescopic portion of the arm 20 will not be deployed; it is only here 
shown deployed for illustrative purposes. 
To gain access to the cockpit the cockpit canopy 10 must first be opened 
and the outer portion 15a of the ejector arm may then be hinged back and 
upwards to improve access to the aircrewmans seat. Once seated the hinged 
arm may be lowered to its normal position. Any helmet-mounted optical 
equipment may then be attached to the line depending from the inertia 
reel-in device. The aircrewman may then freely move his head with the 
retaining line attached. It has been found to be convenient to provide 
electrical power for any helmet-mounted electrical or electro-optical 
equipment by use of a flexible cable also depending from the inertia 
reel-in device. This is advantageous because it removes the need for 
batteries to be checked or replaced prior to each flight. At the end of 
each flight the helmet mounted-optical equipment may be detached from the 
line, the outer portion of the arm rotated about its hinge 19 to allow the 
aircrewman to exit from the cockpit. 
In an alternative embodiment of the invention shown in FIG. 3 the ejector 
arm 30 is hinged about a pivot 31 where axis is offset from the roll and 
pitch axes of the aircraft as before. The ejector arm 30 extends forwards 
from the pivot 31 past the side of the ejection seat head box 14. The 
ejector arm is supported on a bracket 32 extending from the side of the 
seat. The bracket may be provided with a roller (not shown) on its upper 
surface to enable the arm to be moved more easily by the seat as it 
commences its ejection sequence. The arm extends to a position about level 
with the aircrewmans helmet 11 and is also provided with a telescopically 
extending portion 33 similar to that described in the other embodiment. 
Attached to the free end of the arm remote from the pivot 31 is an inertia 
reel-in assembly 21 containing cable means 22 attachable to helmet-mounted 
optical equipment 13. 
A particular advantage of the arm passing along the side of the ejection 
seat head box 14 is that the arm will not present a significant 
obstruction to normal entry and exit from the cockpit, and as a 
consequence it is not necessary to provide a hinge point along the length 
of the arm. 
In the event that an emergency evacuation of the aircraft is necessary the 
aircrewman will initiate the ejection seat operation. In normal operation 
the sequence commences with the shattering and removal of the canopy 10. 
The path is then clear for the ejection seat to exit from the aircraft 
taking the aircrewman with it. 
In the embodiment of the invention shown in FIG. 3, the modified sequence 
is as follows. At the same time as the canopy is shattered or very shortly 
afterwards the helmet-mounted optical equipment 13 is separated from the 
helmet by use of either an electrical, pneumatic or mechanical separation 
means. The separation means are arranged to project the equipment forward 
and away from the helmet. The telescopic portion 33 is also extended by a 
different pneumatic, electrical or mechanical means (not shown) triggered 
by the ejection seat timing mechanism. These extension means will normally 
be contained in or mounted on the ejector arm 30 and the rapid extension 
of the telescopic portion 33 causes the inertia reel-in assembly to lock, 
so that as the arm is extended it will pull the optical equipment 13 away 
from the aircrewman's helmet. By this time the optical equipment will be 
separatd from the helmet 11, thus it is removed away from the aircrewman 
in a direction not likely to cause injury. Once the telescopic portion 33 
is fully extended the ejection seat will begin to rise out of the cockpit. 
In so doing it will cause the ejector arm 30 to rotate about its pivot 31. 
To facilitate this movement and ensure smooth operation the roller and 
bracket assembly it attached securely to the head box of the ejection 
seat. The support bracket 32 is intended to provide a guide and support 
during routine operaion of the seat but could additionally be fitted with 
a roller or other aid to assist smooth and rapid rotation of the arm. 
In either embodiment, the ejection seat rises and a very rapid rotation of 
the ejector arm 15 about its pivot point will ensue by virtue of the 
mechanical advantage of the system, thereby projecting the optical 
equipment, supported on the end of a line depending from the inertia 
reel-in apparatus, clear of the cockpit and ejecting aircrewman so that 
the aircrewman may eject in safety. Once clear of the cockpit and in the 
airstream the line securing the jettisoned equipment to the inertia 
reel-in device will probably fracture due to the very high loadings and 
the equipment will fall freely away. The offset and pivot angle will 
anyway ensure that the jettisoned equipment follows a different path from 
that of the ejection seat and the particular arrangement of this apparatus 
ensures that the helmet-mounted equipment will be jettisoned before the 
aircrewman ejects from the cockpit.