| JP2000230538 | HINGE MECHANISM AND HEAD MOUNT DISPLAY DEVICE |
| JP2003027321 | DEVICE FOR MOUNTING PROTECTIVE GEAR FOR HELMET |
| JP11323649 | COMPOSITE HELMET |
Adrian, Dampney
Ian
Trevor
Adrian, Dampney
Ian
Trevor
| 1. | A thermal imaging system for connection to a fireman's helmet, comprising a generally Ushaped module adapted to fit beneath the lower edge of the helmet, and having first and second side portions, arranged so that in use the side portions are positioned on either side of the wearer's head, a rear portion joining the two side portions together and arranged so that in use the rear portion is positioned at the back of the wearer's head, and an eyepiece portion extending from the front of the second side portion so as to be positioned in use in front of at least one of the wearer's eyes, a thermal imaging camera housed in the first side portion of the module, an image projection system housed in the second side portion of the module and arranged to present a visual image to the wearer's eye, the image projection system being connected electrically to the thermal imaging camera through connection means housed in the rear portion of the module. |
| 2. | A thermal imaging system as claimed in Claim 1, in which the module is adapted for releasable connection to the helmet. |
| 3. | A thermal imaging system as claimed in Claim 1 or Claim 2, in which the eyepiece is positioned, in use, in front of only one of the wearer's eyes, the imaging system presenting a visible image to that eye, the other eye remaining unobstructed. |
| 4. | A thermal imaging system as claimed in any preceding claim, and for connection to a fireman's helmet of the kind having a relatively broad rim extending around the bottom of the helmet, in which the module is adapted to fit beneath the rim of the helmet. |
This invention relates to a thermal imaging system for connection to a fireman's helmet. More particularly, but not exclusively, the invention relates to a thermal imaging system for connection to a fireman's helmet of the kind having a relatively broad rim extending around the bottom of the helmet.
It is desirable to provide a thermal imaging system which can be carried on a fireman's helmet. Such systems proposed hitherto have the thermal imaging system mounted on the top of the helmet, or have components of the system mounted at the sides of the helmet. Because the components of the thermal imaging system are relatively heavy, this can cause the helmet to become unbalanced, increasing the discomfort of wearing the helmet, particularly for long periods, and can also impair the impact resistance of the helmet.
It is an object of this invention to provide an improved thermal imaging system for connection to a fireman's helmet.
This invention consists in a thermal imaging system for connection to a fireman's helmet, comprising a generally U-shaped module adapted to fit beneath the lower edge of the helmet, and having first and second side portions, arranged so that in use the side portions are positioned on either side of the wearer's head, a rear portion joining the two side portions together and arranged so that in use the rear portion is positioned at the back of the wearer's head, and an eyepiece portion extending from the front of the second side portion so as to be positioned in use in front of at least one of the wearer's eyes, a thermal imaging camera housed in the first side portion of the module, an image projection system housed in the second side portion of the module and arranged to present a visual image to the wearer's eye, the image projection system being connected electrically to the thermal imaging camera through connection means housed in the rear portion of the module.
Preferably, the module is adapted for releasable connection to the helmet.
The thermal imaging system of this invention is particularly suitable for connection to a fireman's helmet of the kind having a relatively broad rim extending around the lower part of the helmet, the module being adapted to fit beneath the rim of the helmet. However, it is envisaged that the invention may be applicable to other forms of helmet.
Since the module is attached to the helmet beneath its lower edge, the weight of the thermal imaging system is positioned as low as possible, improving the balance of the helmet and alleviating the discomfort of the wearer. The shape of the module, and its position, minimises the extent to which the addition of a thermal imaging system to the helmet hampers movement of the wearer. In particular, the invention avoids the problem of thermal imaging components mounted on the top of the helmet, which can make it more difficult for the fireman to move around, particularly when visibility is poor, without the components mounted on the helmet striking obstructions. The overall width of the module can be relatively great, so long as it is less than normal shoulder width, without greatly hampering the fireman in moving in confined spaces. Since fitting the module to a helmet does not require modification of the shell of the helmet, there is no risk of adversely affecting the required characteristics of the helmet shell, for example in meeting impact resistance requirements.
Another problem which can arise with thermal imaging systems proposed hitherto for mounting on a fireman's helmet is that the visible image is presented to both the wearer's eyes through an eyepiece positioned in front of the eyes. This means that the wearer can see only the image presented by the thermal imaging system, and if he wishes to use unaided sight as to remove the helmet or move the eyepiece out of the way, it would be advantageous to provide a thermal imaging system for a fireman's helmet which enabled the fireman to switch easily between viewing the image provided by the system and using unaided sight, for example when moving into or out of a smoke filled environment.
In accordance with another aspect of this invention, a thermal imaging system for connection to a fireman's helmet is provided with an eyepiece positioned, in use, in
front of only one of the wearer's eyes, the imaging system presenting a visible image to that eye, the other eye remaining unobstructed.
The fireman can therefore use one eye to view the thermal image and the other for normal sight. If the thermal imaging system is adjusted so that the wearer has to refocus his eyes slightly when changing from viewing the thermal image to using unaided sight, this will assist the wearer in using the desired image whilst ignoring the other.
Thus, in the thermal imaging system according to the first aspect of the invention, the eyepiece portion can be arranged to extend over only one of the user's eyes. This has the additional advantage of reducing further the weight of the system.
Since the wearer can then use unaided sight with the eyepiece portion in position, the eyepiece portion can be permanently fixed in position on the second side portion of the module. However, there may be circumstances in which it would be desirable to be able to move the eyepiece out of the way. The eyepiece portion may therefore alternatively be movably attached to the side portion of the module. For example, the eyepiece portion may be pivoted to the side portion of the module.
The side portions and rear portion of the module may be formed in one piece. Alternatively, the rear portion may be divided, preferably at its mid-point, to divide the module into two halves. The two halves may be hinged together, for example for pivotal movement about a vertical axis to facilitate fitting the module to the helmet. Alternatively, the two halves may be separable, a suitable releasable connection being provided between the two halves of the rear portion. A plug and socket connection may be provided to provide the necessary electrical connection between the two halves of the module.
A battery to power the thermal imaging system may be housed in the module, or in a separate housing carried by the fireman and connected to the 'module by a flexible cable.
The invention will now be described, by way of example, with reference to the accompanying drawings, in which:
Figure 1 is a perspective view of a thermal imaging system in accordance with the invention,
Figure 2 is a diagrammatic view of the thermal imaging system, showing the positions of the optical components of the system,
Figure 3 is a diagrammatic side elevation of the thermal imaging system, and
Figure 4 is a diagrammatic front elevation of the thermal imaging system.
Referring to the drawings, a thermal imaging system is provided for a fireman's helmet 10 of the kind having a relatively broad rim 12 extending around the bottom of the helmet. The thermal imaging system comprises a rigid module 20 which is generally U-shaped in plan view so as to fit between the rim 12 and embrace the back and sides of the wearer's head. The module has a flat upper face 22 which lies against the underside of the rim 12 of the helmet 10. The module 20 is releasably connected to the helmet 10 by any suitable means, for example by means of plate 24 fixed to the chin strap mountings usually provided at the sides of the helmet and having studs 26 which engage in keyhole mounting apertures 28 formed in the upper wall of the module, and a suitable connector 30 at the rear of the module for connection to the helmet rear mounting.
The module 20 has two side portions 32 and 34 joined by a rear portion 36, and an eyepiece portion 38 extending from the front of the side portion 34 to a position in front of the wearer's left eye.
The side portion 32 of the helmet 10 houses a thermal imaging camera and objective lens system 40. A window 42 transparent to infra-red radiation is provided in the front wall 44 of the side portion 32. The optical axis of the camera and objective lens
system is arranged at an angle to the upper face 22 of the module 20, so that, when the helmet is worn, the optical axis is generally parallel to the normal line of sight of the wearer.
The side portion 34 of the module 20 houses an image projection system 50, connected electrically to the camera 40 by means of leads, such as ribbon wiring 52, extending through the rear portion 36 of the module 20. The image projection system forms a visible image of the scene viewed in infra-red radiation by the camera 40. An arrangement of mirrors 54 in the eyepiece portion 38 of the module presents the visible image to the left eye of the wearer.
The module 20 consists of a hollow moulding of suitable plastics, formed with mounting points for the components of the thermal imaging system. Removable access covers, not shown, are provided in the wall of the module to allow access to the various components. A layer of thermal insulation is provided to protect the components.
The module 20 may incorporate a housing for a battery to power the system. Alternatively, a separate battery housing may be provided for attachment to the fireman's clothing, connected to the module by a flexible cable.
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