Classifications

• • A—HUMAN NECESSITIES
  • A42—HEADWEAR
  • A42C—MANUFACTURING OR TRIMMING HEAD COVERINGS, e.g. HATS
  • A42C2/00—Manufacturing helmets by processes not otherwise provided for
  • A42C2/007—Manufacturing custom-sized helmets

Definitions

• the present invention applies to the manufacture of any helmet that must be precisely positioned on the wearer's head
• Helmets with a viewfinder are essentially used by the military for infantrymen or pilots of airplanes and helicopters
• helmets include on the one hand the helmet proper intended for the passive protection of the wearer of the helmet and on the other hand a visual integrated into this helmet and intended for the presentation of information to the eyes of said wearer
• the wearer designates the person for whom the helmet is made, even if, in certain phases of the described production, this person is bareheaded
• the helmet consists of a rigid protective shell resistant to puncture and a thick inner shell, more flexible, for comfort and protection against shocks II usually includes an audio communication system, possibly a respiratory system , and moreover supports the visual if it is a helmet with integrated visual
• the visual is an optical display device which presents a video image of external reality or a synthetic image on a "combiner", that is to say on a semi-reflecting screen which allows simultaneous vision of the real world and of the image presented
• the image is produced by an image generator, for example a cathode ray tube, a liquid crystal screen or a matrix of light-emitting diodes
• a relay optics placed between the image generator and the combiner ensures collimation of the image to transform it into a virtual image
• the "combiner" is produced by the visor of the helmet itself
• FIG. 1 represents such a helmet, with its rigid shell 10, its internal shockproof cap 12
• the display 14 comprises an imager (HERE a cathode ray tube for projection) 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 only ensured if the eye is placed at a very precise position relative to the optical paths defined by the visual, therefore at a very precise position by in relation to all the elements making up the visual, elements which themselves must be positioned very precisely with respect to each other.
• the difficulty lies in this rigorous positioning of the visual relative to the eye of the helmet wearer.
• the relative positioning tolerance is for example 1 millimeter and 1 degree between the optical system, the optical paths which it defines, and the eye of the wearer.
• FIG. 2 represents such a helmet with adjustment means 22 with four degrees of freedom according to three translations and a rotation in elevation.
• Another solution is to postpone the adjustment of the helmet to its internal cap.
• the visual is then rigidly fixed to the shell and a personalized internal cap jointly adapts the helmet to the morphology of the wearer and the correct positioning of the visual relative to the wearer's eye.
• the helmet is then completely adapted to the morphology of the wearer and the visual is correctly placed for this wearer only.
• the difficulty lies in the production of this personalized internal cap, this production having to result in the visual being always correctly placed, without an accessory mechanical adjustment system.
• This personalization can be done in practice by making a personalized lining that the wearer has inside a standard helmet. The filling can be produced,.
• the thrust and the exothermic chemical reaction of the injected foam depend on its density, that is to say on the ratio between the quantity of material injected and the actual volume comprised between the head and the internal 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.
• the invention aims to produce a personalized helmet in a simpler manner and avoiding as much as possible the drawbacks of the methods of the prior art.
• the invention provides a method of manufacturing a helmet comprising a personalized internal cap ensuring the positioning of the helmet on the wearer's head, characterized by a prior reading of the shape of the wearer's head by a measurement device without contact, which prior reading is followed by an implementation of said cap from this reading.
• the preliminary reading is preferably done by an optical measurement process, in particular by a laser beam scanner which rotates around the head of the user by recording the distances between this scanner and points of the head to obtain in the form of data. digital head shape.
• - Figure 2 shows an embodiment of the helmet of the prior art
• - Figure 3 shows a helmet with a personalized lining in use
• - Figure 4 shows 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.
• a personalized lining is made to be inserted between the head and the standard (non-personalized) shockproof cap of the helmet. But we will understand that we could also directly make a personalized 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 lining composed of a foam 34 with flocking 35 on the side of the wearer's head.
• FIG. 4 represents the preferred implementation of the invention.
• the statement of the shape of the head of the wearer is a contactless digital reading, such as for example, a two-dimensional digital reading obtained by a 3D scanner digitizing profiles formed by a plane laser beam.
• Such a survey of the shape of a head can consist of a digitization of meridians illuminated by the laser and captured by a camera in a rotary scanning head 52 rotating around a vertical axis 53 of a fixed platform 55 .
• the wearer for example wears a thin elastic cap intended to press the hair on the skull as the helmet would do and having a color and a surface condition suitable for the scanner.
• the carrier is then placed in an armchair, the back of which is tilted in a manner representative of the seat of the aircraft.
• the wearer places himself in a natural head posture by fixing his gaze horizontally by 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 an 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 so as to match the top of the subject's skull with the axis of mechanical rotation 53 of the scanner, then adjusted in height in order to optimize the shape and reduce the gray areas.
• the complete scanning of the head can be carried out in one revolution of the scanner in 15 seconds.
• the average resolution of this scanning is close to 0.5 millimeter and the precision of the order of 0.1 millimeter.
• the session ends with the measurements of the spatial coordinates of the eyes and possible anatomical points, by aiming at different glasses.
• the device of FIG. 5 measures the position of 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 ruler with digital coding, respectively 59, 60 and 61, these rulers make it possible to measure two coordinates of a point of the wearer to be digitized
• the system of digital rulers and glasses is previously 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 placed in front of him
• a telescope 56 is arranged in front of the wearer's face and allows an operator to read the coordinates of the wearer's eyes in height and in width by adjusting the position of this telescope.
• the other two glasses 57 and 58, orthogonal to the telescope 56, are placed on either side of the wearer so that the operator measures the depth dimension on the one hand with the left eye by adjusting the position of the telescope of sight 57, and on the other hand of the right eye by adjustment of the telescope 58
• Digitization of the wearer's head is then used to make the custom trim defined above, as well as internal elements of the helmet such as the position of the headphones
• This digitization can be used by a digital age machine to make an internal mold for the lining.
• a standard base 63 in which a personalized internal mold 64 is inserted, and on the other hand a standard external mold 65, corresponding to the interior shape of the helmet's standard shockproof cap.
• the internal mold has a standard internal face 67 making it possible to position it precisely with respect to the base 63 and a personalized external face 66 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 filling the cavities 69 and 70.
• the filling can also be produced 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 trim is placed in a standard helmet.
• Such a helmet manufacturing method allows the realization of a helmet with integrated visual adapted to the wearer without adding a mechanical device for adjusting the visual. It makes it possible to separate in time and in space the two main stages of embodiments consisting on the one hand of the statement of shape of the head and on the other hand of the realization of the personalized lining.
• 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 head even for the wearer, immobilization is ensured painlessly by a simple bite board without taking a dental impression.
• the necessary statement of head shape is more exactly limited to the statement of the part of the head which is used to define the personalized trim.
• the first stage requires the wearer's presence limited to a few tens of minutes and, for more comfort, a head shape measurement device can be installed, for example, in a truck for allow to carry out the measurements in the workplace of helmet wearers.
• the second step is carried out without the wearer, for example in the factory because the adjustment of the helmet on the wearer's head is defined in the first step.
• Another advantage of the invention is the fact that the prior shape survey makes it possible to determine in advance the quantity of material to be injected to produce the personalized cap.

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• Engineering & Computer Science (AREA)
• Manufacturing & Machinery (AREA)
• Helmets And Other Head Coverings (AREA)

Applications Claiming Priority (3)

Publications (2)

Family

ID=9491633

Family Applications (1)

Country Status (6)

Cited By (1)

Families Citing this family (9)

Family Cites Families (7)

• 1996
  • 1996-04-26 FR FR9605309A patent/FR2747895B1/fr not_active Expired - Fee Related
• 1997
  • 1997-04-18 WO PCT/FR1997/000706 patent/WO1997040716A1/fr active IP Right Grant
  • 1997-04-18 EP EP97920788A patent/EP0957697B1/de not_active Expired - Lifetime
  • 1997-04-18 DE DE69707507T patent/DE69707507T2/de not_active Expired - Lifetime
  • 1997-04-18 AU AU27039/97A patent/AU729446B2/en not_active Ceased
  • 1997-04-25 ZA ZA9703631A patent/ZA973631B/xx unknown

Non-Patent Citations (1)

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