GB2178868A

GB2178868A - Optical arm for viewing apparatus mounted fixed on a vehicle

Info

Publication number: GB2178868A
Application number: GB08618165A
Authority: GB
Inventors: Claude Weber
Original assignee: Societe dEtudes et de Realisations Electroniques
Current assignee: Societe dEtudes et de Realisations Electroniques
Priority date: 1985-08-08
Filing date: 1986-07-25
Publication date: 1987-02-18
Also published as: FR2586111A1; GB8618165D0; GB2178868B; IT8621304A0; DE3625684A1; FR2586111B1; KR870002470A; IT8621304A1; KR900005742B1; IT1197022B

Abstract

This optical arm for viewing or aiming apparatus mounted fixed on a vehicle, of the type which is angled and comprises an eye piece carrier and in which the incident beam is returned by a system of parallel mirrors and/or prisms to at least one eye piece carrier, comprises means (5, 6, 10, 16, 19) adapted to enable the eye piece carrier (7) to be displaced only horizontally and vertically in a single plane perpendicular to the trajectory of the incident optical beam ofthe apparatus, to the exclusion of all displacement parallel to this trajectory (11). <IMAGE>

Description

SPECIFICATION Optical arm for sighting equipment mounted on a vehicle This invention relates in a general mannerto observation apparatus or aiming apparatus, mounted on military vehicles, and it is more particularly con- cerned with an optical arm intended for use with such apparatus.

Helicopters or land vehicles (armour-plated or otherwise) provided with systems of fixed arms for non-guided projectiles comprise such optical apparatus,which is fixedly mounted on the fuselage orthe cockpit ofthe helicopter, or on the body ofthe vehicle, inside which is situated the observer who uses the apparatus by means of at least one optical armex- tending into the interior of the vehicle.

However, optical observation or aiming apparatus which is fixed to the vehicle is subject to accelerations, decelerations, vibrations or other movements ofthevehicle, of a chance character, whereasthe observer sitting in the vehicle reacts in a different mannerto theforces to which his body is subject as a result of such movements, across his seat and other possible points ofsupport, such as elbow-rests, footrests etc.

In such operating conditions, the movements ofthe head of the observer generally occur at different times to those of the optical arm and its eyepieces and, even ifthe aiming apparatus is provided with a gyroscopic stabilising system, this results in disturb ance ofthe observation and the aiming, due to partial obstruction produced by the differential movements ofthe eyepieces and the observer's eyes and to fati gue and to disturbances of vision dueto impacts and vibrations transmitted by the front support on the eypepiece hoods.

Attempts have been made to remedythesedisadvantages by mounting the observation apparatus on the vehicle by means of a suspension arrangement intended to filter out the disturbing movements in orderto reduce them.

However, such a suspension arrangement has the major disadvantage of separating the aiming axis of the vehicle and its system of arms, which then prevents its use in all cases in which it is necessaryto know precisely the position ofthe sighting line ofthe observation apparatus in relation to the vehicle.

It would be advantageous to provide an optical arm arrangementforsuch an aiming or observation apparatus which overcomes these disadvantages by preventingthetransmission offorces, vibrations and shockstotheobserverthroughthe intermediary of the front support and hoods of the eyepieces.

The invention provides an optical arm forobservation oraiming apparatus mounted on avehicle,ofthe type comprising an eyepiece carrier and angle bends, in which the incident beam is directed by a system of parallel mirrors and/or prism to at least one eyepiece of such eyepiece carrier, further comprising articulation means arranged to allow such eyepiece carrier to moveonlyverticallyand horizontally in a single plane perpendicularto the path of the incident optical beam of the apparatus.

According to anotherfeature of the invention, such articulation means comprise a first angled portion of the arm connected bya first bearing to the viewing apparatus and buy a second bearing to a second por tion ofthe arm, which is likewise angled and itself connected by a third bearing to the eyepiece carrier, the bearings all being arranged in planes parallel to each other and perpendiculartotheviewing axis.

According to one embodiment, the first portion of the arm, connected to the apparatus, has two angle bends in the same sense and the second portion of the arm, connected both to the first portion and to the eyepiece carrier, has two angle bends in the opposite sense.

According to an alternative arrangement, the first portion of the arm, connected to the apparatus, has two angle bends of opposite sense and the second portion ofthe arm, connected both to the first portion and tothe eyepiece carrier, has two angle bends in the same sense.

According to anotherfeature of the invention, the eyepiece carrier comprises removable means for holding the head of the observer stationary with respectto the eyepiece carrier, in contact therewith.

Preferably, the means for holding the head ofthe observer comprise self-securing strips fixed on the sides ofthe eyepiece carrier and co-operating with complementarystripsfixed on the sides of the observer's helmet.

In an advantageous manner, the second part ofthe arm is held in an intermediate position in relation to the first by means of a return spring.

Certain embodiments ofthe invention will hereinafter be described by way of example only and with reference to the accompanying drawings in which: Figure lisa diagrammatic view of an optical arm according to the invention in an intermediate or nor mal operating position, as it appearstothe observer: Figure2 is a side elevation, the arm being entirely extended downwardly in order to show more clearly its arrangement and the path of the optical beam; Figure3is a view corresponding to that of Figure 2 of an alternative arrangement; Figure 4is a partial view from above, showing the observer's helmet immobilised with respect to the eyepiece carrier.

Referring to the drawing, reference 1 designates the upperwall of the cockpit of a helicopter, on which an aiming apparatus 2 is fixedly mounted, as viewed from the position of the observer, that is to say from the back towards the front.

The aiming apparatus 2 comprises a housing having a frontwindow 3 and an optical porthole 4 located inside the helicopter.

An articulated optical arm isfixed by one endtothe optical porthole 4 and comprises firstand second tubular parts 5 and 6 articulatedtogetherand carries at its opposite end an eyepiece carrier 7.

According to the example shown in Figure 2, the first part5 ofthe arm has two right-angle bends 8,9 in the same sense at the ends of an intermediate rectilinear part,theangle bend 8 being fixed to the aiming apparatus2 by means of a bearing 10 located ina plane perpendicular to the path of the exit light beam 11 ofthe aiming apparatus.

The exit light beam 11 ofthe aiming apparatus is reflected bya mirror 12 mounted at45in the angle bend 8 and then by a roof prism 13 mounted in the angle bend 9 such that the light beam 11' leaves it parallel to the part 1 1.

Thesecondportion6oftheoptical arm hastwo right-angle bends 14,15 in the opposite sense at the ends of an intermediate rectilinear part.

The angle bend 14 is articulated to the angle bend 9 by means of a bearing 16 disposed in a planeperpen- dicularto the path 11' of the optical beam having the angle bend 9 ofthe portion 5.

Two oblique parallel mirrors 17,18 reflect the optical beam, following a path 11" parallel to the beam 11', to the eyepiece carrier 7, which is itself articulated to the angle bend 15 by means of a bearing 19 disposed in a plane perpendicularto the path ofthe optical beam 11", which is itself parallel to the path of the exit light beam 11 ofthe aiming apparatus.

Itwill be understood that as a result of this mount- ins the bearings 10, and 19 are parallel to each otherandthatthe portions 5,6 ofthe arm andthe eyepiece carrier may each turn with respecttothe others and with respect to the aiming apparatus 2 around the path ofthe exit light beam 11, but without being ableto shift parallel tothis path.

It will also be understood that the eyepiece carrier7 can thus be freely displaced horizontally and vertically in a plane perpendiculartothe exit beam 11(11', 11".

The eyepiece carrier7 is provided, in known manner,with a frontsupport20 around the eyepiece or eyepieces.

According to the invention, at each side ofthe eyepiece carrier 7, means are provided for connecting itto the observer's head.

According to the example shown in the drawing, these means comprise two self-securing flexible bands or ribbons 21 ("Velcro" Reg. Trade Mark) fixed to the eyepiece carrier 7 and co-operating with complementary bands 22 fixed on the observer's helmet.

Alternatively, use can also be made of an elastic band fixed by its ends to the eyepiece carrier and extendablearoundthehelmetordirectlyaroundtheobser ver's head.

In the embodiment of figure 3, the portions 25,26 of the optical arm are reversed with respect to the example of Figure 2, that is the portion 26 having two right-angle bends of opposite sense is articulated to the optical porthole 4 ofthe aiming apparatus, whilst the portion 25 has two right-angle bends of the same sense and is articulated to the eyepiece support, the remainder of the arrangement being identical.

The lower part 6 or 25 of the optical arm is conveniently suspended in an intermediate position by a spring 27 connected between the two parts ofthe arm.

The bearings 10,16,19 are preferably ball bearings damped to suppress all axial movements, in order that the eyepiece carrier7 may not be displaced para Ileltotheexitoptical beam 11.

The damping means comprise exerting an axial force on one ofthe two races of each bearing.

When the aiming apparatus 2 fixed to the vehicle is subjected to disturbing movements along the axes X-Y (Figure 1) and the head ofthe observer is subjected to different relative movements, the eyepiece carrier, which is disconnected from such movements through the relative pivoting ofthe portions ofthe arm and the eyepiece carrier, is held opposite the eye ofthe observer, who can thus see a vertical image.

Alternatively, the self-securing ribbons may be fixed on the front support and on the visor of the observer's helmet.

Claims

1. An optical armforobservation oraimingapparatus mounted on a vehicle, ofthetype comprising an eyepiece carrier and angle bends and in which the incident beam is directed by a system of parallel mirrors and/or prisms to at least one eyepiece of such eyepiece carrier, further comprising articuiation means arranged to allow such eyepiece carrier to be displaced only horizontally and vertically in a single plane perpendicular to the path of the incident optical beam ofthe apparatus.

2. An optical arm according to claim 1, wherein the said articulation means comprise a first angled portion ofthe arm connected by a first bearing to the viewing apparatus and by a second bearing to a second portion ofthe arm, also angled and itself connected by a third bearing to the eyepiece carrier, the said bearings being all disposed in planes parallel to each other and perpendiculartothe path ofthe optical beam.

3. An optical arm according to claim 2, wherein the said first portion of the arm, connected to the apparatus has two angle bends inthesamesense, and the said second portion ofthe arm connected by one part to the first portion and by the other parttothe eyepiece carrier has two angle bends in the opposite sense.

4. An optical arm according to claim 2, wherein the saidfirst portion of the arm, connected to the apparatus has two angle bends in the opposite sense, and the second portion ofthe arm connected by one parttothefirst portion and bythe other parttothe eyepiece carrier hastwo angle bends in thesame sense.

5. An optical arm according to claim 3 or claim 4, wherein the second portion ofthe arm is maintained suspended in an intermediate position in relation to the first portion by means of a spring connected between the said portions.

6. An optical arm according to any preceding claim, wherein the eyepiece carrier comprises detachable means for maintaining the head of the observer stationary in relation to the eyepiece carrier in contact therewith.

7. An optical arm according to claimS, wherein the said detachable means comprise self adhesive ribbons fixed on the sides of the eyepiece carrier and co-operating with complementary ribbons fixed on the sides of the observer's helmet.

8. An optical arm substantially as hereinbefore described with reference to the accompanying drawings.