EP0957697B1 - Method for manufacturing personalised helmets - Google Patents

Description

The present invention applies to the manufacture of any helmet to be precisely positioned on the wearer's head.

Viewfinder helmets are mainly used by military forces for infantrymen or pilots of airplanes and helicopters. These helmets include on the one hand the helmet proper intended for the passive protection of the helmet wearer and on the other hand a visual integrated into this helmet and intended for the presentation of information in the eyes of said wearer.

In the following text, the bearer designates the person for which the helmet is made, even if, in certain phases of the realization described, this person is bareheaded.

The helmet consists of a resistant rigid protective shell with a perforation and a thicker, more flexible inner shell for comfort and impact protection. It most often includes a system of audio communication, possibly a respiratory system, and further supports the visual if it is a helmet with integrated visual.

The visual is an optical display device which has a video image of external reality or a synthetic image on a "combiner", that is to say on a semi-reflecting screen which allows the simultaneous vision of the real world and the image presented. The image is produced by an image generator, for example a cathode ray tube, a liquid crystal display or a matrix of light emitting diodes. Relay optics placed between the image generator and the combiner collimates the image to transform it into a virtual image. In some achievements, the "combiner" is made by the visor of the helmet herself.

FIG. 1 represents such a helmet, with its rigid shell 10, its internal shockproof cap 12. The display 14 includes an imager (here a tube projection cathode) 16, a projection visor 18 constituting the "combiner" mentioned above, and between the imager and the visor, the relay optics 20.

A correct vision of the image by the wearer of the helmet is not assured that if the eye is placed at a very precise position in relation to optical paths defined by the visual, therefore at a very precise position by relation to all the elements making up the visual, elements which themselves must be positioned very precisely with respect to other.

The difficulty lies in this rigorous positioning of the visual compared to the helmet wearer's eye.

The relative positioning tolerance is for example 1 millimeter and 1 degree between the optical system, the optical paths it defines, and the wearer's eye.

A simple solution is to make a helmet with a visual mechanically adjustable relative to the shell so as to adjust the position of the visual to that of the wearer's eye. Figure 2 shows such a helmet with adjustment means 22 with four degrees of freedom according to three translations and a site rotation.

However, such an adjustment device is complex, it increases the mass and size of the head equipment, it induces fragility in use and a loss of characteristics and reliability in the time. In addition, if the helmet wearer makes the adjustments himself, he can adjust them. do it wrong.

Another solution is to postpone the adjustment of the helmet to the level of its internal cap.

The visual is then rigidly fixed to the shell and a cap internal custom jointly performs the adaptation of the helmet to the morphology of the wearer and the correct positioning of the visual in relation to the wearer's eye.

The helmet is then completely adapted to the morphology of the carrier and the display is correctly placed for this carrier only. The difficulty lies in the realization of this personalized internal cap, this achievement should lead to the visual being always correct placed, without additional mechanical adjustment system.

This personalization can be done in practice by making a personalized lining that the wearer places inside a helmet standard. The lining can be produced by direct molding, on the head of the wearer by injecting polyurethane foam between the wearer's head and a shape which is the inner shape of the helmet's shockproof cap, everything keeping the head and said shape in exact relative position such that the is correctly positioned in relation to the wearer's eyes. After polymerization of the foam and release from the mold, a filling is obtained which will be placed inside the helmet.

But this process is delicate to implement because of the thrust caused by the foam on the wearer's head especially. This push leads to too large displacements (from around 5 millimeters while the tolerance is set at +/- 1 millimeter) between the eyes and the visual. It is difficult to compensate for this defect with a prior offset, because the offset depends in fact on the morphology and the bodybuilding specific to each carrier.

In addition, the exothermic thrust and chemical reaction of the foam injected depends on its density, that is to say on the ratio between the amount of material injected and the actual volume between the head and the inner shape of the shockproof cap, this volume being very difficult to measure in practice. This also leads to uncertainty about the final positioning accuracy obtained.

• douleurs pendant l'opération du fait des systèmes d'immobilisation utilisés (l'utilisateur doit mordre une planche de positionnement pour maintenir sa tête en place), maux de tête éventuels dus au produit utilisé et à la réaction exothermique,
• impossibilité de réalisation si la morphologie de l'utilisateur sort d'une gamme de morphologies prédéfinies, ou bien nécessité d'augmenter systématiquement la quantité de mousse à injecter et le volume global du casque pour tenir compte de morphologies plus variées,
• encombrement important de l'installation, nécessité de deux ou trois opérateurs expérimentés, et durée importante (plusieurs heures) de l'opération.

Other disadvantages of this process also exist:

• pain during the operation due to the immobilization systems used (the user must bite a positioning board to keep his head in place), possible headaches due to the product used and to the exothermic reaction,
• impossibility of realization if the morphology of the user leaves a range of predefined morphologies, or else need to systematically increase the amount of foam to be injected and the overall volume of the helmet to take into account more varied morphologies,
• significant size of the installation, need for two or three experienced operators, and significant duration (several hours) of the operation.

The invention aims to produce a custom helmet in a way simpler and avoiding the disadvantages of the processes as much as possible of the prior art.

For this, the invention provides a method of manufacturing a helmet including a personalized internal cap ensuring positioning of the helmet on the wearer's head characterized by a reading prior to the shape of the wearer's head by a measuring device without contact, which prior reading is followed by an implementation of said cap at from this statement.

The presence of the carrier is then only necessary for the statement prior; it is not necessary for the realization of the internal cap. The constraints for the wearer are much less and the problems encountered due to the direct injection of foam on the wearer's head disappear.

The prior reading is preferably done by a process of optical measurement, in particular by a laser beam scanner which revolves around from the user's head by reading the distances between this scanner and head points to get as digital data the shape of the head.

Since the user's eye position is very important, such a statement is preferably supplemented by a precise measurement the position of the wearer's eyes in order to constitute the statement of form digitized. This measurement of the position of the eyes is preferably done by optical means.

From the shape report, we can machine or define by molding the inner surface of the inner shell of the helmet to achieve the customization, that is to say that we machine or mold either the internal shell itself be a custom trim that fits into a cap internal standard to complete it.

• la figure 1, déjà décrite, est un schéma général de casque de pilote avec viseur;
• la figure 2, également déjà décrite, représente une réalisation de casque de la technique antérieure;
• la figure 3, également déjà décrite, représente un casque avec une garniture personnalisée en situation d'utilisation ;
• la figure 4, représente un dispositif de relevé de la forme de la tête fournissant un relevé numérique par rotation d'un appareil de mesure autour de la tête;
• la figure 5, représente un moule de garniture personnalisée avec ses parties standard et son moule interne personnalisé.

The invention will be better understood on reading the detailed description which follows and which is made with reference to the following figures in which:

• Figure 1, already described, is a general diagram of pilot helmet with sight;
• Figure 2, also already described, shows an embodiment of helmet of the prior art;
• Figure 3, also already described, shows a helmet with a personalized lining in use;
• FIG. 4 represents a device for reading the shape of the head providing a digital reading by rotation of a measuring device around the head;
• Figure 5 shows a custom trim mold with its standard parts and its custom internal mold.

The preferred implementation of the invention will now be described. In this implementation, a personalized packing is made to insert between the head and the standard shockproof cap (not personalized) of the helmet. But we will understand that we could also directly realize a customized shockproof cap.

FIG. 3 represents a helmet on the head of its wearer 36 with its shell 30 and its standard internal cap 31, in which is placed, using positioning pins 32 and 33, a gasket composed of a foam 34 with fiocage 35 on the side of the wearer's head. With such a helmet, personalization is limited to that of the lining.

FIG. 4 represents the preferred implementation of the invention. In this implementation, the statement of the shape of the wearer's head is a contactless digital reading, such as a digital reading two-dimensional obtained by a 3D scanner digitizing profiles formed by a plane laser beam.

Such a statement of the shape of a head may consist of a scanning of laser-illuminated meridians captured by a camera in a rotary scanning head 52 rotating around an axis vertical 53 of a fixed platform 55.

To facilitate the digitization of the shape of the head by such scanner, the wearer wears for example a thin elastic cap intended for flatten the hair on the skull as the helmet would and presenting a color and surface condition suitable for the scanner.

The wearer is then placed in a chair whose back is tilted representative of the aircraft seat. The wearer stands in a natural posture of the head by fixing his gaze horizontally while looking at his image in the semi-reflecting mirror 54 placed in front of him. The stationary position of the head is maintained by a bite plate, a chin rest or ergonomic neck brace adjustable according to the six degrees of freedom and connected to the chair.

The chair is movable relative to the fixed platform 55, it is moved in the horizontal plane to match the top of the subject's skull with mechanical axis of rotation 53 of the scanner, then adjusted in height in order to optimize the shape survey and reduce the areas shade.

The complete scanning of the head can be carried out in one scanner revolution in 15 seconds.

The average resolution of this scan is close to 0.5 millimeter and the accuracy of about 0.1 millimeter.

The session ends with measurements of spatial coordinates of the eyes and possible anatomical points, by sightings of different glasses.

To allow rigorous positioning of the helmet visual relative to the wearer's eye, the device of FIG. 4 measures the position from the center of each eye of the wearer relative to the fixed platform 55.

Each of the three riflescopes 56, 57 and 58 is placed on a linear rule with digital coding, respectively 59, 60 and 61, these rules allow to measure two coordinates from a point of the carrier to digitize. The system of numerical rules and glasses is beforehand harmonized in position with the scan mark of the scanner using a calibration piece.

The wearer maintains his gaze using the semi-reflecting mirror 54 arranged before him.

A telescope 56 is placed in front of the wearer's face and allows an operator to read the coordinates of the eyes of the wearer at height and in width by adjusting the position of this telescope.

The other two glasses 57 and 58, orthogonal to the bezel 56, are placed on either side of the carrier so that the operator measures the depth dimension on the one hand with the left eye by adjusting the position of the telescopic sight 57, and on the other hand with the right eye by adjusting the telescope 58.

Scanning the wearer's head is then used to make the custom trim defined above, as well as elements internal headphones such as the position of the headphones.

This scan can be used by a machining machine digital to make an internal mold of the filling.

A filling mold realization is presented on the figure 5, it comprises on the one hand a standard base 63 in which a custom internal mold 64, and on the other hand a standard external mold 65, corresponding to the internal shape of the standard shockproof cap of the helmet.

The internal mold has a standard internal face 67 allowing it to be positioned precisely with respect to the base 63 and a face external 66 personalized representing the shape of the wearer's head. The external mold 65 fits on the base so as to obtain a space corresponding to the lining between the external mold 65 and the internal mold 64. The lining is thus produced by injection through the orifice 68 when the two molds 65 and 64 are blocked on the base 63. Centering pins are formed on the lining during this molding operation by the filling of cavities 69 and 70.

The filling can also be made from a block of foam, by machining using a digital machine using the above digitization, then dressing with a term of comfort and finish.

After manufacture, the personalized packing is placed in a standard helmet.

Such a helmet manufacturing method allows the realization of a helmet with integrated visual suitable for the wearer without adding a device mechanical adjustment of the display.

It allows to separate in time and space the two main stages of achievements made up of a statement of form of the head and on the other hand of the realization of the personalized garnish.

The shape record described in the preferred implementation of the invention is clean and not very restrictive for the wearer since there is no thrust exerted on the head, as in the production of lining by direct molding on the wearer's head, immobilization being ensured painlessly with a simple bite board without taking an impression dental.

The necessary statement of head shape is more exactly limited to the statement of the part of the head used to define the lining customized.

The first step requires the wearer's presence limited to a few tens of minutes and, for more comfort, a reading device head shape can be installed, for example, in a truck for allow to carry out the readings in the workplace of the carriers of helmet.

The second step is carried out without the carrier, for example by factory because the helmet adjustment on the wearer's head is defined in the first stage.

Spare fittings can be supplied on request without constraint of presence of the carrier.

Likewise it is possible to integrate options in the realization of the filling without repeating the shape taking, for example, the choice of material of the upholstery, the choice of the finishing fabric, the choice of the type of helmet or even the choice of the position of the visual on site.

Another advantage of the invention is the fact that the statement of form allows to determine in advance the quantity of material to be injected to make the personalized cap.

Claims (11)

1. Method of manufacturing a helmet comprising a personalized internal cap which positions the helmet on the wearer's head, characterized by a prior determination of the shape of the wearer's head by a non-contacting measurement device, which prior determination is followed by production of the said personalized cap on the basis of this determination.
2. Method according to Claim 1, characterized in that the prior determination of the shape of the wearer's head is performed by a 3-D optical scanner.
3. Method according to either of Claims 1 and 2, characterized in that the personalized cap is machined with the aid of a numerical-control machine on the basis of the prior shape determination.
4. Method according to either of Claims 1 and 2, characterized in that the personalized cap comprises a standard cap into which a- personalized lining is inserted.
5. Method according to either of Claims 1 and 2, characterized in that a mould for a personalized cap is produced from the determination.
6. Method according to Claim 4, characterized in that a mould for a personalized lining is produced from the determination.
7. Method according to one of Claims 1 to 6, characterized in that during the prior determination the position of the user's eyes is determined in three dimensions.
8. Method according to Claim 7, characterized in that the position of the eyes is measured by a device determining at least the coordinates of the eyes in terms of height and in terms of width and the depth of each of the eyes.
9. Method according to Claim 7 or 8, characterized in that the position of the eyes is determined by an optical device.
10. Method according to one of Claims 7 to 9, characterized in that the head is immobilized during the determination of the shape and of the position of the eyes.
11. Method according to one of Claims 1 to 10, characterized in that the helmet comprises a built-in display device requiring very precise positioning with respect to the wearer's eyes.

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